Solution tank system with end-line valve

Abstract

The present invention provides a solution tank system that has a structure which is simple and which makes it possible to ensure high sealing performance, and that facilitates the connection between an actuator and a pin which forms the valve body of an end-line valve. A solution tank system is characterized by comprising: a first solution tank (3) that contains a first solution and first air, a lid (11) that blocks the opening at the upper end of the first solution tank (3); a first channel (2-1) that enters a bottom portion of the first solution tank (3) from the outside of the first solution tank (3) through the lower surface of the first solution tank (3), that extends vertically upward in the inside of the bottom portion, that terminates after extending so as to be inversely tapered toward the inside of the first solution tank (3), and that contains a second solution; and a first valve (7) that opens and closes the end of the first channel (2-1), wherein the first valve (7) has a pin (13) which has a tapered tip which passes through the lid (11) to enter the first solution tank (3), the first solution can meet the second solution at the end of the first channel (2-1), and when the pin (13) is moved downward, the tip of the pin (13) blocks the end so that the first valve (7) closes, and when the pin (13) is moved upward, the tip of the pin (13) moves away from the end so that the first valve (7) opens.

Description

Solution tank system with an end line valve

[0001] The present invention relates to a solution tank system provided with an end line valve used in a capillary electrophoresis system or the like.

[0002] A capillary electrophoresis apparatus is an automatic apparatus that analyzes a sample by performing electrophoresis inside a capillary. Inside the capillary, various types of components contained in the sample solution are separated according to their mobility according to charge and size. For example, Applied Biosystems TM. SeqStudio TM. Flex Series Genetic Analyzers (hereinafter referred to as the conventional apparatus A) can perform DNA sequencing and DNA fragment analysis as described in Non-Patent Document 1.

[0003] The conventional apparatus A can perform parallel analysis using 8 or 24 capillaries. In this specification, a capillary electrophoresis apparatus equipped mainly with one capillary will be described as an example, but the same description also holds when multiple capillaries are provided. Hereinafter, the conventional apparatus A will be described while referring to Figure 2 and Figure 23 of Non-Patent Document 1.

[0004] In the conventional apparatus A, the anode end of the capillary is connected to the internal flow path of the anode block ((1) Polymer block in Figure 23). The anode block has a built-in pump for pressurizing the polymer solution. The lid of the anode buffer solution tank ((3) Anode buffer container in Figure 23) containing the anode electrode and the anode buffer solution is connected to the anode block.

[0005] The internal channels of the anode block are connected to the internal channels of the lid of the anode buffer solution tank. These channels terminate inside the anode buffer solution tank. The internal channels of the anode block and the internal channels of the lid are filled with polymer solution during electrophoresis, etc. The polymer solution functions as a separation medium in electrophoresis.

[0006] At the end of the flow path from the anode block to the anode buffer solution tank, near the boundary between the polymer solution and the anode buffer solution, a valve is installed to open and close this flow path. In this specification, this type of valve is called an end-line valve because it is located at the end of the flow path. When the pin ((2) Buffer-pin valve in Figure 23) is pushed down to block the end, the end-line valve is closed. Conversely, when the pin is pushed up to open the end, the end-line valve is opened.

[0007] With the endline valve closed, a pump can apply high pressure to the polymer solution inside the anode block. Applying high pressure allows the high-viscosity polymer solution to fill the capillary from the anode end to the cathode end. For example, a high pressure of 35 atmospheres is applied to the polymer solution. When filling with polymer solution is not performed, the endline valve is opened. When the endline valve is opened, the inside of the anode block and the anode end of the capillary are exposed to the atmosphere.

[0008] Conventional device A is equipped with a solenoid actuator to move the pin that forms the valve body of the endline valve up and down. The plunger of the solenoid actuator and the pin that forms the valve body are connected via a connecting lever. In addition, the connecting lever and the pin are connected by an interlocking structure in order to allow the pin to move in both directions up and down while making the lid removable. The lid that supports the pin is fixed to the main body of conventional device A. In contrast, the anode buffer solution tank is supported by the lid.

[0009] The cathode end of the capillary is inserted through the cathode electrode, which is a hollow electrode in the shape of a pipe, and the two are integrated. The spatial position of the cathode end is fixed in a position facing vertically downward. The cathode buffer solution tank containing the cathode buffer solution, the sample solution tank containing the sample solution, the washing water tank containing the washing water, and the waste liquid tank containing the waste liquid are fixed on an automated XYZ stage. By driving the automated XYZ stage, the cathode end can be immersed in the desired solution. The solution in which the cathode end is immersed is always open to the atmosphere.

[0010] By immersing the cathode end of a capillary in a sample solution and applying a voltage between the cathode electrode and the anode electrode, i.e., between both ends of the capillary, components contained in the sample solution can be injected into the capillary from the cathode end. Alternatively, by immersing the cathode end in a cathode buffer solution and applying a voltage between both ends of the capillary, electrophoresis can be performed. In this specification, electrophoresis performed with both ends of the capillary at atmospheric pressure is sometimes referred to as atmospheric pressure electrophoresis.

[0011] Figure 1 of Patent Document 1 describes a capillary electrophoresis apparatus (hereinafter referred to as Conventional Apparatus B) similar to Conventional Apparatus A. Although Conventional Apparatus A and Conventional Apparatus B have some differences in configuration, their basic specifications and performance are equivalent. Figure 7 shows the upper polymer block, anode-side buffer container, and lower polymer block of Conventional Apparatus B, which correspond to the anode block, anode buffer solution tank, and lid of the anode buffer solution tank of Conventional Apparatus A.

[0012] In the conventional apparatus B, the anode end of the capillary 3 is connected to the flow paths 31a to 31e inside the upper polymer block 34, which corresponds to the anode block. A syringe 31 is connected to the upper polymer block 34 as a pump for pressurizing the polymer solution. The anode-side electrode 6b and anode buffer solution 15a are contained in the anode-side buffer container 15.

[0013] The lid of the buffer container 15 on the anode side is formed as a lower polymer block 15c. The lower polymer block 15c is connected to the upper polymer block 34 via a tube that forms a channel 15b. The channel 31e inside the upper polymer block 34 is connected to the channel 15e inside the lower polymer block 15c via the channel 15b inside the tube. During electrophoresis, the channel 15b inside the tube, the channel 31e inside the upper polymer block 34, and the channel 15e inside the lower polymer block 15c are filled with polymer solution.

[0014] The flow path 15e inside the lower polymer block 15c extends toward the tip of the protrusion 15c' of the lower polymer block 15c, then bends vertically upward and terminates inside the anode-side buffer container 15. At the end of the flow path from the upper polymer block 15c to the anode-side buffer container 15, near the boundary between the polymer solution and the anode buffer solution 15a, a pin valve PV, which corresponds to an end-line valve, is installed. When the pin valve PV is pushed down to block the end, the end-line valve becomes closed. Conversely, when the pin valve PV is pushed up to open the end, the end-line valve becomes open.

[0015] U.S. Patent No. 7459068

[0016] SeqStudioTM.Flex Series Genetic Analyzer with Instrument Software v1.1,1 USER GUIDE, Thermo Fisher Scientific Inc., 2023, 24 Jul. <URL: https: / / assets.thermofisher.com / TFS-Assets / LSG / manuals / 100104689_SeqStudioFlex_v1_RUO_UG.pdf>

[0017] Conventional anode buffer solution tanks and their lids have the following common problems. For anode buffer solution tanks and other solution tank systems that transport and fill solutions, it is desirable to solve at least the first problem, and preferably the first to fourth problems.

[0018] <First Challenge> The lids of conventional anode buffer solution tanks have a complex structure due to factors such as the curved shape of the internal flow path. This results in larger lid sizes and higher manufacturing costs. This challenge becomes more apparent when miniaturizing the equipment, reducing equipment costs, or when the anode buffer solution tank and its lid are treated as consumables.

[0019] <Second Challenge> Conventional anode buffer solution tanks are not airtight despite being covered with a lid. Therefore, there is a high risk of the anode buffer solution leaking out of the tank due to vibrations, for example, when transporting the electrophoresis apparatus. In particular, the lid of the anode buffer solution tank has a through hole for inserting a pin that forms a valve body. A gap is provided between the inner wall of the through hole and the side of the pin to allow the pin to move up and down. There is a possibility that the anode buffer solution may leak out through this gap.

[0020] <Third Challenge> Conventional anode buffer solution tanks are not sealed, making it impossible to control the internal pressure to a predetermined level by pressurizing or depressurizing the inside. This challenge becomes more apparent when performing double-ended pressurized electrophoresis. Double-ended pressurized electrophoresis is performed with both ends of the capillary tube under pressure. Double-ended pressurized electrophoresis is performed for purposes such as ensuring stable and highly accurate capillary electrophoresis analysis.

[0021] <Fourth Challenge> The pins that form the valve body of conventional endline valves need to be connected to the plunger of the solenoid actuator via a connecting lever. The connecting lever and the pins need to be connected by an interlocking structure. Such a structure is complex and requires the effort of forming the interlocking structure each time the cover is attached or removed. This challenge becomes more apparent when the cover is attached and removed frequently, or when the connection between the connecting lever and the pins is automated.

[0022] Therefore, the present invention aims to provide a solution tank system that has a simple structure, can ensure high airtightness, and facilitates the connection between the pins forming the valve body of the endline valve and the actuator.

[0023] To solve the above problems, the solution tank system according to the present invention comprises: a first solution tank containing a first solution and a first air; a lid that closes the opening at the upper end of the first solution tank; a first flow path that enters from the outside of the first solution tank into the bottom of the first solution tank from the lower surface of the first solution tank, extends vertically upward through the interior of the bottom, widens in an inverse tapered shape toward the interior of the first solution tank and terminates therein, containing a second solution; and a first valve that opens and closes the end of the first flow path. The first valve has a pin with a tapered tip that penetrates the lid and enters the interior of the first solution tank, the first solution and the second solution can merge at the end of the first flow path, when the pin is moved downward, the tip of the pin closes the end and the first valve closes, and when the pin is moved upward, the tip of the pin separates from the end and the first valve opens.

[0024] According to the present invention, it is possible to provide a solution tank system that has a simple structure, can ensure high airtightness, and facilitates the connection between the pins forming the valve body of the endline valve and the actuator.

[0025]

[0026] The following describes a solution tank system equipped with an endline valve according to an embodiment of the present invention. In the following figures, common components are denoted by the same reference numerals, and redundant explanations are omitted. In some cases, some reference numerals indicating common components may be omitted in the following figures.

[0027] <Solution to the First Problem> The reason why the structure of the lid of conventional anode buffer solution tanks is complex can be summarized as follows (A) to (F): (A) The flow path exists only inside the lid and not inside the anode buffer solution tank. With such a structure, when the anode buffer solution tank is removed from the lid, such as when changing the anode buffer solution, it is easy to reattach the anode buffer solution tank to the lid. (B) The boundary between the polymer solution and the anode buffer solution separated by the end line valve is inside the anode buffer solution tank and near the liquid surface of the anode buffer solution. Therefore, it is possible to keep the stroke of the pin associated with opening and closing the end line valve small, and thus the actuator that moves the pin up and down can be simplified. (C) Because the stroke of the pin can be kept small, the risk of the tip of the pin coming off the end line valve when the pin descends is reduced. (D) Because the stroke of the pin can be kept small, fluctuations in the liquid surface height of the anode buffer solution can be suppressed to a small extent in response to the movement of the pin associated with opening and closing the end line valve. (E) By suppressing fluctuations in the liquid level, the effect on electrophoresis can be reduced. During electrophoresis, it is necessary to move the pin upward and open the end line valve. At this time, the tip of the pin is not in contact with the anode buffer solution, or is only slightly in contact. Therefore, the effect of the pin being immersed in the anode buffer solution on electrophoresis can be reduced. (F) Since the boundary between the polymer solution and the anode buffer solution separated by the end line valve is inside the anode buffer solution tank and near the liquid surface of the anode buffer solution, if air bubbles form near the end line valve, the bubbles are more likely to escape into the air layer due to buoyancy.

[0028] As a means of solving the first problem, at least one of the channels inside the anode block and the channels formed inside the tube connected to the channels inside the anode block is connected from the bottom of the anode buffer solution tank, rather than from the top of the lid as in conventional electrophoresis apparatuses. Furthermore, a straight channel is formed inside the bottom of the anode buffer solution tank, avoiding bends in the channel. This structure allows the end line valve to be positioned near the bottom of the anode buffer solution tank.

[0029] According to this solution to the first problem, the structure of the anode buffer solution tank and its lid is simplified. Therefore, it becomes easier to reduce the size of the anode buffer solution tank and its lid. In addition, the manufacturing cost of the anode buffer solution tank and its lid can be kept low.

[0030] However, such solutions make it difficult to address (A) to (F) above, which may be an obstacle to adoption. Possible solutions to address (A) to (F) above include the following: (A) Connecting the anode block and the anode buffer solution tank via a tube. Also, attaching a detachable connector to the tube to facilitate attachment and detachment of the tube. Alternatively, making the anode buffer solution tank and its lid consumables, eliminating the need for the user to replace the anode buffer solution inside. (B) Since the position of the endline valve moves from near the liquid surface of the anode buffer solution to near the bottom of the anode buffer solution tank, if the design is such that the pin does not touch the anode buffer solution when the endline valve is open, as in the conventional design, the stroke of the pin associated with opening and closing the endline valve will be large. Therefore, the design should ensure that the pin is immersed in the anode buffer solution even when the endline valve is open. More specifically, the design should ensure that the tip of the pin is located near the bottom of the anode buffer solution tank when the endline valve is open. This design reduces the stroke of the pin and simplifies the actuator for moving the pin up and down. (C) The design, with the tip of the pin positioned near the bottom of the anode buffer solution tank when the endline valve is open, reduces the pin stroke and minimizes the risk of the pin tip detaching from the endline valve during descent. (D) The design, with the tip of the pin positioned near the bottom of the anode buffer solution tank when the endline valve is open, reduces the pin stroke and minimizes fluctuations in the liquid level of the anode buffer solution in response to the movement of the pin due to the opening and closing of the endline valve. (E) The pin material is made of a material with low chemical reactivity, such as polyetheretherketone (PEEK) resin. By selecting an appropriate material, the effects of pin immersion in the anode buffer solution are avoided, even when the pin is immersed in the anode buffer solution. Experiments have confirmed that materials with low chemical reactivity have little effect on electrophoretic analysis.(F) Because the position of the end line valve moves from near the liquid surface of the anode buffer solution to near the bottom of the anode buffer solution tank, the distance required for bubbles generated near the end line valve to reach the liquid surface of the anode buffer solution or the air layer increases. However, experiments have confirmed that bubbles generated near the bottom of the anode buffer solution tank can easily escape into the air layer due to buoyancy.

[0031] From the above, it was found that the solution to the first problem described above can address (A) to (F) above, and that (A) to (F) above do not hinder its adoption. Therefore, by adopting such a solution to the first problem, the structure of the anode buffer solution tank and its lid can be simplified while maintaining the advantages of conventional electrophoresis apparatus. Thus, the anode buffer solution tank and its lid can be miniaturized. In addition, the manufacturing cost of the anode buffer solution tank and its lid can be reduced.

[0032] <Means for Solving the Second Problem> As a means for solving the second problem, a sealing member such as an O-ring is interposed between the upper surface of the side wall of the anode buffer solution tank and the lower surface of the lid of the anode buffer solution tank. By compressing the sealing member between the upper surface of the side wall of the anode buffer solution tank and the lower surface of the lid, the gap between the anode buffer solution tank and the lid can be sealed. The sealing member does not necessarily have to be annular; it may be rectangular or annular. It may also be a composite structure with multiple members joined together, such as an oil seal, and may have a lip, nose, etc. To maintain the compressed state of the sealing member such as an O-ring, it is effective to firmly fasten and fix the anode buffer solution tank and its lid with screws or the like.

[0033] Furthermore, as a means of solving the second problem, the gap between the pin and the through-hole through which the pin is inserted, provided in the lid of the anode buffer solution tank, is sealed by the following means: An enlarged portion is provided on the side of the pin below the lid to enlarge the outer diameter of the pin. When the pin moves upward, a sealing member such as an O-ring is compressed between the upper surface of the enlarged portion and the lower surface of the lid, thereby sealing the gap between the through-hole and the pin. Alternatively, an enlarged portion is provided on the side of the pin above the lid to enlarge the outer diameter of the pin. When the pin moves downward, a sealing member such as an O-ring is compressed between the lower surface of the enlarged portion and the upper surface of the lid, thereby sealing the gap between the through-hole and the pin. Alternatively, a sealing member such as an O-ring is attached to the side of the pin located inside the through-hole, so that regardless of the vertical position of the pin, the sealing member such as an O-ring is compressed between the side of the pin and the inner surface of the through-hole, thereby sealing the gap between the through-hole and the pin.

[0034] According to this solution to the second problem, the anode buffer solution tank is properly sealed. The risk of the anode buffer solution leaking out of the tank due to vibrations during transport of the electrophoresis apparatus can be avoided. In particular, even if a through-hole for inserting a pin is provided in the lid of the anode buffer solution tank, leakage of the anode buffer solution through the gap between the through-hole and the pin can be avoided.

[0035] <Means for Solving the Third Problem> As a means for solving the third problem, after sealing the anode buffer solution tank using the means for solving the second problem, a through-hole for piping, different from the through-hole through which the pin is inserted, is provided on the upper surface of the lid of the anode buffer solution tank, and an air tube is connected to this through-hole, with the outer end of the air tube open to the atmosphere. By reducing the inner diameter of the air tube, even if vibration is applied to the electrophoresis apparatus, the possibility of the anode buffer solution inside the anode buffer solution tank leaking out through the air tube is reduced. A valve can also be provided in the middle of the air tube. If there is a possibility of vibration being applied to the electrophoresis apparatus, the anode buffer solution can be prevented from leaking out by closing the valve in the middle. However, while the valve is closed, it is not possible to control the pressure inside the anode buffer solution tank to a predetermined level.

[0036] Alternatively, after sealing the anode buffer solution tank using the solution to the second problem, a through-hole for piping, different from the through-hole through which the pin is inserted, is provided on the upper surface of the lid of the anode buffer solution tank, and an air tube is connected to this through-hole, with the outer end of the air tube connected to an air source that supplies pressure-controlled air. As the air source, an electro-pneumatic regulator that proportionally controls the air pressure can be used. The pressure inside the anode buffer solution tank can be adjusted to a desired pressure by controlling the connection to a space of the desired pressure. The pressure inside the anode buffer solution tank can be increased to a positive pressure by pressurizing it above atmospheric pressure, or decreased to a negative pressure by depressurizing it below atmospheric pressure.

[0037] This solution to the third problem allows for adjusting the pressure inside the sealed anode buffer solution tank to an appropriate level. Because the pressure applied to the anode end of the capillary can be adjusted, it becomes possible to perform double-ended pressurized electrophoresis, where both ends of the capillary are immersed in a pressurized solution.

[0038] <Solution to the fourth problem> As a solution to the fourth problem, an enlargement portion is provided on the side of the pin below the lid of the anode buffer solution tank to enlarge the outer diameter of the pin. In addition, a head portion is provided on the upper side of the pin to enlarge the outer diameter of the pin. Between the lower surface of the head portion and the upper surface of the lid, a spring that is compressed to its natural length is installed concentrically with the pin. The compressed spring, through its restoring force as it expands, moves the pin upward and opens the endline valve. On the other hand, when the head portion is pushed down by the actuator, the pin moves downward and the endline valve closes. After that, when the downward pressure on the head portion is released, the pin moves upward again due to the restoring force of the spring and opens the endline valve. In other words, when moving the pin downward, the actuator is used, but when moving the pin upward, the elasticity of the spring is used and the actuator is not used.

[0039] This solution to the fourth problem simplifies the structure of the lid of the anode buffer solution tank through which the pin is inserted. There is no need to connect the pin and the actuator with a connecting lever or the like, or to connect the connecting lever or the like to the pin with an interlocking structure. Because the connection structure is simplified, the effort of forming the interlocking structure each time the lid is attached or detached can be eliminated. As the actuator that drives the pin, in addition to a solenoid actuator equipped with a plunger, any other actuator, such as an air cylinder, can also be used.

[0040] <Definitions of In-Line Valves and End-Line Valves> Figure 1 shows the main components of a solution tank system. Figure 1 shows the arrangement of in-line valves and end-line valves provided in a solution tank system to explain the definitions of in-line valves and end-line valves. An in-line valve is a valve that opens and closes the middle section of the flow path through which the solution is delivered. An end-line valve is a valve that opens and closes the end section of the flow path through which the solution is delivered. The cross-sectional area of ​​the flow path (the cross-sectional area of ​​the plane perpendicular to the direction of solution flow) is the same before and after the in-line valve. In contrast, the cross-sectional area of ​​the flow path (the cross-sectional area of ​​the plane perpendicular to the direction of solution flow) changes significantly before and after the end-line valve.

[0041] As shown in Figure 1, in the solution tank system, a channel 2 (hole 4) is formed inside the channel material 1. The internal channel 2 (hole 4) and the inside of the solution tank 3 are connected via an external channel 2 (tube 5). The channel material 1 is a component used for transporting and filling liquids and semi-fluids, and is formed as a resin block or chip, etc. The internal channel 2 is a hole formed by machining, injection molding, bonding of components, etc., and is therefore referred to as a hole. In contrast, the external channel 2 is formed inside a tube, and is therefore sometimes simply referred to as a tube.

[0042] In FIG. 1, the interior of the internal flow path 2 (hole 4), the interior of the external flow path 2 (tube 5), and the interior of the solution tank 3 are filled with the solution 8. An in-line valve 6 is disposed at an intermediate portion located between the ends of the internal flow path 2 (hole 4) and at an intermediate portion located between the ends of the external flow path 2 (tube 5). A valve disposed at such an intermediate portion of the flow path is called an in-line valve. An end-line valve 7 is disposed at the end of the external flow path 2 (tube 5), that is, at the position (boundary) where the external flow path 2 (tube 5) is connected to the solution tank 3. A valve disposed at such an end of the flow path is called an end-line valve.

[0043] <Conventional Capillary Electrophoresis Apparatus> FIG. 2 is a diagram showing the configuration of a conventional capillary electrophoresis apparatus. As shown in FIG. 2, the capillary 101 is attached with the cathode end 102 on the side of the cathode buffer solution tank 109 (right side) and the anode end 103 on the side of the anode block 118 (left side). Both ends of the capillary 101 are arranged to face vertically downward. The capillary 101 is formed, for example, by polyimide coating a quartz glass tube. The capillary 101 has, for example, an outer diameter of 360 μm and an inner diameter of 50 μm.

[0044] The anode end 103 of the capillary 101 is pressure-tightly connected to an acrylic anode block 118 via a connector 117. Pressure-tight connection means a connection that is sealed so that the contents do not leak out even when the pressure of the internal liquid or semi-fluid rises. However, in this specification, a pressure-tight connection may sometimes be simply referred to as a connection.

[0045] Inside the anode block 118, a flow path 137 having an inverted T-shape when viewed from the side is formed. The internal flow path 137 includes a portion that penetrates the anode block 118 in the horizontal direction and a portion that branches from an intermediate portion of this portion and penetrates above the anode block 118. The internal flow path 137 of the anode block 118 is filled with a polymer solution 121 during electrophoresis or the like.

[0046] As the polymer solution 121, for example, POP-7 manufactured by Thermo Fisher Scientific is used. A pressure-resistant syringe 119 and a tube forming an external flow path 122 outside the anode block 118 are pressure-resistant connected to a flow path 137 inside the anode block 118. The polymer solution 121 fills the inside of the pressure-resistant syringe 119 and the external flow path 122 during electrophoresis or the like. The pressure-resistant syringe 119 and the tube forming the external flow path 122 are connected via a connector (not shown).

[0047] The end of the external flow path 122 on the side opposite to the anode block 118 is inserted into the anode buffer solution tank 123 and immersed in the anode buffer solution 125 stored in the anode buffer solution tank 123. An end line valve 128 is installed at the boundary between the external flow path 122 connecting the anode block 118 and the anode buffer solution tank 123 and the inside of the anode buffer solution tank 123.

[0048] Although the structure of the solution tank provided with the end line valve is shown in a simplified manner in FIG. 2, it is shown in detail in FIGS. 3 to 20 and the like. In the following description, the anode buffer solution tank is taken as a main example of the solution tank provided with the end line valve, but it is not limited to the anode buffer solution tank.

[0049] The end line valve 128 includes a pin 127 forming a valve body. The pin 127 is provided so as to be movable up and down. When the pin 127 moves upward, the end line valve 128 is in the "valve open" state. On the other hand, when the pin 127 moves downward, the end line valve 128 is in the "valve closed" state.

[0050] A conventional electrophoresis apparatus includes a solenoid actuator for moving the pin 127 up and down and a connection lever for interlocking the solenoid actuator and the pin 127. The connection lever is a component that engages with a meshing structure capable of pushing down and pulling up the pin 127 in order to move the pin 127 in both the up and down directions. However, these are not shown in FIG. 2 and the like.

[0051] A cylindrical anode electrode 106 is inserted into the anode buffer solution tank 123. The tip of the anode electrode 106 is immersed in the anode buffer solution 125 contained in the anode buffer solution tank 123. The electrophoresis apparatus is equipped with a temperature control device (not shown) to maintain a constant temperature for the capillary 101. For example, when performing DNA sequencing or DNA fragment analysis, it is considered appropriate to maintain the temperature of the capillary 101 at 60°C.

[0052] The cathode end 102 of the capillary 101 is inserted into a hollow, pipe-shaped cathode electrode 105 and integrated with the cathode electrode 105. The cathode buffer solution tank 109, which contains the cathode buffer solution 110, and the sample solution tank 111, which contains the sample solution 112, are fixed on the cathode stage 114. The cathode stage 114 is coupled to an automated XYZ stage (not shown). The automated XYZ stage is itself movable in three axes and moves the cathode stage 114 relative to the cathode end 102.

[0053] Note that other containers, such as multiple sample solution tanks containing different sample solutions, can also be fixed to the cathode stage 114, but these are not shown in Figure 2. Figure 2 shows the cathode end 102, which is integrated with the cathode electrode 105, inserted into the cathode buffer solution tank 109 and immersed in the cathode buffer solution 110.

[0054] The detection position 104 is located at a predetermined distance from the cathode end 102 on the capillary 101. The area of ​​the capillary 101 near the detection position 104 is provided without polyimide coating. At the detection position 104, a laser beam 136 emitted from the laser light source 135 irradiates the inside of the capillary 101. Inside the capillary 101, sample components labeled with a fluorescent dye undergo electrophoresis. At the detection position 104, fluorescence is emitted from the fluorescent dye due to excitation by the laser beam 136. The emitted fluorescence is detected by a fluorescence detector (not shown).

[0055] The anode electrode 106 and cathode electrode 105 are connected to a DC high-voltage power supply 108 via wires 107 and a switch 139. When the switch 139 is turned ON, a high DC voltage is applied between the anode electrode 106 and the cathode electrode 105, creating a potential difference between the anode end 103 and the cathode end 102 of the capillary 101. The formation of this potential difference enables electric field implantation, which injects sample components contained in the sample solution into the capillary 101, and electrophoresis, which separates sample components according to their mobility.

[0056] In conventional electrophoresis apparatuses, the vertical heights of the interface between the cathode buffer solution 110 and air in the cathode buffer solution tank 109 (the liquid surface of the cathode buffer solution 110) and the interface between the anode buffer solution 125 and air in the anode buffer solution tank 123 (the liquid surface of the anode buffer solution 125) are equal. For example, the difference in height between the two liquid surfaces is set to 1 mm or less. These conditions prevent the polymer solution 121 inside the capillary 101 from moving due to the difference in hydrostatic head during electrophoresis.

[0057] Next, we will explain the general analytical procedure using capillary electrophoresis. Capillary electrophoresis is performed by carrying out the following steps in this order: [1] polymer solution filling, [2] preliminary electrophoresis, [3] sample injection, and [4] electrophoresis.

[0058] [1] At the start of polymer solution-filled electrophoresis, the cathode stage 114 is moved by an automatic XYZ stage to insert the cathode end 102 into a waste tank (not shown). Next, the pin 127 is moved downward to close the end line valve 128. In this state, the plunger 120 of the pressure-resistant syringe 119 is mechanically pushed in using a stepping motor to apply pressure to the polymer solution 121 inside the anode block 118.

[0059] The polymer solution 121 inside the anode block 118, the polymer solution 121 in the channel 122 connecting the anode block 118 and the anode buffer solution tank 123, and the polymer solution 121 inside the pressure-resistant syringe 119 form a continuous liquid system. Closing the valve as described above encloses this liquid system in a sealed space, and virtually no air is contained within the sealed space. Furthermore, the anode end 103 is immersed in this liquid system.

[0060] Therefore, the high pressure applied by the plunger 120 is transmitted throughout the entire liquid system, including the anode end 103. On the other hand, the cathode end 102 is immersed in the cathode buffer solution 110 under atmospheric pressure. As a result, a high pressure difference is formed between the anode end 103 and the cathode end 102. This pressure difference causes the polymer solution 121 to fill the inside of the capillary 101 from the anode end 103 to the cathode end 102.

[0061] The pressure applied to this liquid system can be adjusted by controlling the force of the stepping motor that pushes the plunger 120. For example, a high pressure of 35 atmospheres is applied to the liquid system to fill the capillary 101 with polymer solution 121 at high pressure. After filling with polymer solution 121, the pushing of the plunger 120 is stopped, separating the plunger 120 from the mechanism that mechanically pushes the plunger 120, so that no external pressure is applied to the liquid system.

[0062] However, in reality, some pressure may remain due to frictional resistance of the plunger 120, and the pressure applied to the liquid system may not be zero. Therefore, the pin 127 is moved upward to open the end line valve 128, and the anode end 103 and the liquid system are opened to the atmosphere. If the anode buffer solution tank 123 does not have a lid that can be sealed, opening the end line valve 128 will bring the anode side to the same atmospheric pressure as the outside.

[0063] [2] After filling the capillary 101 with polymer solution 121, the cathode stage 114 is moved by an automatic XYZ stage to insert the cathode end 102 into the cathode buffer solution tank 109 and immerse it in the cathode buffer solution 110. In this state, a predetermined voltage is applied between the anode end 103 and the cathode end 102 for a predetermined time to perform preliminary electrophoresis. Preliminary electrophoresis reduces variations in charge, etc., inside the capillary 101.

[0064] [3] Sample injection When injecting a sample into the capillary 101, the cathode stage 114 is moved by the automatic XYZ stage so that the cathode end 102 is inserted into the sample solution tank 111 and immersed in the sample solution 112. In this state, a predetermined voltage is applied between the anode end 103 and the cathode end 102 for a predetermined time to perform electric field injection of the sample. By electric field injection, the components contained in the sample solution 112 are injected into the inside of the capillary 101 from the cathode end 102.

[0065] [4] Electrophoresis When electrophoresis is performed on the sample, the cathode stage 114 is moved by the automatic XYZ stage so that the cathode end 102 is inserted into the cathode buffer solution tank 109 and immersed in the cathode buffer solution 110. In this state, a voltage is applied between the anode end 103 and the cathode end 102 to perform electrophoresis of the sample.

[0066] When repeating analyses using multiple capillary electrophoresis methods, the above steps [1] to [4] are repeated. In Figure 2, the anode buffer solution tank 123 and the cathode buffer solution tank 109 do not have airtight lids to cover them, and the anode buffer solution 125 and cathode buffer solution 110 are exposed to the atmosphere. In this state, where both ends of the capillary 101 are under atmospheric pressure, atmospheric pressure electrophoresis is performed.

[0067] <Conventional Solution Tank System with Endline Valve (0)> Figure 3 shows the configuration of a conventional solution tank system (0) equipped with an endline valve. Figure 3 shows the cross-sectional structure of an anode buffer solution tank and its lid equipped with a conventional endline valve. The left figure of Figure 3 shows the "valve open" state. The center and right figures of Figure 3 show the "valve closed" state. The center figure of Figure 3 is a cross-sectional view of the anode buffer solution tank 3 and its lid 11 viewed from the front. The right figure of Figure 3 is a cross-sectional view of the anode buffer solution tank 3 and its lid 11 viewed from the right.

[0068] A conventional solution tank system (0) equipped with an endline valve includes an anode buffer solution tank 3, its lid 11, an endline valve 7, an external flow path 2-1 of the anode buffer solution tank 3, and an internal flow path 2-2 of the anode buffer solution tank 3. The anode buffer solution tank 3 and its lid 11 are made of transparent acrylic resin, allowing observation of the internal contents. The lid 11 is fixed to the main body of the capillary electrophoresis apparatus. The anode buffer solution tank 3 is supported by the lid 11 fixed to the main body.

[0069] As shown in the left diagram of Figure 3, the lower surface of the lid 11 is provided with an engaging portion that protrudes downward, to which the O-ring 16-1 is attached. The O-ring 16-1 is attached to the engaging portion. When the upper side of the anode buffer solution tank 3 is fitted with the lid 11 facing the lower surface, the O-ring 16-1 is crushed by the inner wall of the anode buffer solution tank 3. When the O-ring 16-1 is compressed, a sliding frictional force is generated against the relative movement of the O-ring 16-1 and the inner wall of the anode buffer solution tank 3. This frictional force supports the anode buffer solution tank 3 so that it does not fall.

[0070] An electrode 17 is pressure-resistant connected to the lid 11 via a ferrule 12. The electrode 17 penetrates the lid 11 from top to bottom and is inserted into the anode buffer solution tank 3. The tip of the electrode 17 is immersed in the anode buffer solution 8-2 contained inside the anode buffer solution tank 3.

[0071] The anode buffer solution tank 3 is connected to the anode block 118 (see Figure 2) via an external channel 2-1 and an internal channel 2-2. The external channel 2-1 is formed inside the tube 5. For the tube 5, for example, a tetrafluoroethylene-ethylene copolymer (ETFE) tube (outer diameter 1 / 16 inch, inner diameter 0.75 mm) from GL Sciences is used. Inside the lid 11, a hole 4 is formed to form the channel 2-2.

[0072] The external channel 2-1 (tube 5) is connected to the upper surface of the lid 11 from above. The external channel 2-1 (tube 5) is pressure-resistant connected to the lid 11 via a ferrule 12. The ferrule 12 is mounted at an angle so that it moves from the outside of the lid 11 towards the center as it goes from top to bottom. The inner end of the external channel 2-1 (tube 5) is connected to the internal channel 2-2 (hole 4). As the ferrule 12, for example, a PEEK Peak Tough Osine from GL Sciences can be used.

[0073] The internal channel 2-2 (hole 4) extends within the lid 11 toward the center of the anode buffer solution tank 3 along the extension of the external channel 2-1 (tube 5), then folds back vertically upward near the center of the anode buffer solution tank 3, and extends slightly upward from the folding point to terminate. The terminal end of the internal channel 2-2 (hole 4) is formed in an inverse taper shape so that the channel widens from bottom to top. This terminal position is the boundary between the internal channel 2-2 (hole 4) and the inside of the anode buffer solution tank 3. An end line valve 7 is formed at this terminal position.

[0074] The external channel 2-1 (tube 5) and the internal channel 2-2 (hole 4) are filled with polymer solution 8-1, which is the separation medium for capillary electrophoresis, during electrophoresis, etc. Meanwhile, the inside of the anode buffer solution tank 3 is filled with anode buffer solution 8-2 and air 10 under atmospheric pressure. As shown in the right diagram of Figure 3, the anode buffer solution 8-2 is prepared in the anode buffer solution tank 3 such that its liquid level 9 (the boundary between the anode buffer solution 8-2 and the air 10) reaches slightly vertically above the end of the internal channel 2-2 (hole 4).

[0075] The polymer solution 8-1 inside channel 2-2 (hole 4) inside the anode buffer solution tank 3 and the anode buffer solution 8-2 contained inside the anode buffer solution tank 3 become one continuous solution at the end of channel 2-2 (hole 4). In reality, diffusion and mixing make the boundary between the two solutions unclear. However, in this specification, for the sake of easier understanding of the configuration, we assume that a boundary exists between the two solutions at the boundary between channel 2-2 (hole 4) and the inside of the anode buffer solution tank 3.

[0076] A pin 13, which forms a valve body, is inserted into the anode buffer solution tank 3. The pin 13 has a head portion 14 with an enlarged outer diameter and a tip portion 15 with a tapered outer diameter. The pin 13 is installed so that the tip portion 15 is pointed vertically downward and passes through the lid 11. The pin 13 is made of, for example, PEEK, and its body is formed in a cylindrical shape. The outer diameter of the head portion 14 is set to be larger than the outer diameter of the body portion of the pin 13. The tip portion 15 is tapered, decreasing in diameter from top to bottom.

[0077] The head unit 14 is connected to a solenoid actuator (not shown) provided on the main body of the capillary electrophoresis apparatus via a connecting lever (not shown). The connecting lever and the head unit 14 are connected to each other by an interlocking structure or the like. The pin 13 must be movable in both the up and down directions. For this reason, the connecting lever and the head unit 14 must be fixed to each other or engaged by an interlocking structure or the like.

[0078] As shown by the arrow in the left diagram of Figure 3, when the head portion 14 is pulled upward, the tip portion 15 is separated from the terminal end of the internal flow path 2-2 (hole 4), resulting in a "valve open" state. At this time, inside the anode buffer solution tank 3, the tip portion 15 is either not immersed in the anode buffer solution 8-2 or is only slightly immersed.

[0079] Of the analytical steps, step [4] electrophoresis is the longest. The electrophoresis step is performed with the endline valve 7 in the "valve open" position. In other words, the conventional solution tank system (0) is structured so that the pin 13 is hardly immersed in the anode buffer solution 8-2 during electrophoresis. This structure minimizes the influence of the pin 13 on the electrophoretic analysis.

[0080] On the other hand, as indicated by the arrows in the center and right diagrams of Figure 3, when the head portion 14 is pushed downwards, the tip portion 15 is immersed in the anode buffer solution 8-2 and inserted into the reverse-tapered terminal end of the internal flow path 2-2 (hole 4). In other words, the tip portion 15 closes the end of the internal flow path 2-2 (hole 4), resulting in a "valve closed" state.

[0081] The inner diameter of the through-hole 20 formed in the lid 11 through which the pin 13 is inserted is made larger than the outer diameter of the main body of the pin 13. Therefore, the conventional solution tank system (0) has a structure in which a gap exists between the through-hole 20 and the pin 13. With this structure, the inside of the anode buffer solution tank 3, that is, the anode buffer solution 8-2 and air 10 contained in the anode buffer solution tank 3 are maintained at atmospheric pressure.

[0082] In conventional solution tank systems (0), the above-mentioned problems <1st problem> to <4th problem> arise mainly due to the structure of the anode buffer solution tank 3, the lid 11, the internal flow path 2-2 (hole 4) of the anode buffer solution tank 3, and the pin 13. Therefore, in the embodiment of the present invention, improvements are made to the structure of the solution tank and its surroundings.

[0083] <Solution tank system (1) equipped with an endline valve according to an embodiment of the present invention> Figure 4 is a diagram showing the configuration of a solution tank system (1) equipped with an endline valve according to an embodiment of the present invention. Figure 4 shows the cross-sectional structure of an anode buffer solution tank and its lid, which is equipped with an endline valve on the bottom side. The left diagram of Figure 4 shows the "valve open" state. The right diagram of Figure 4 shows the "valve closed" state.

[0084] The solution tank system (1) according to this embodiment includes an anode buffer solution tank 3, its lid 11, an end-line valve 7, an external flow channel 2-1 of the anode buffer solution tank 3, an internal flow channel 2-2 of the anode buffer solution tank 3, and so on. The capillary electrophoresis apparatus using the solution tank system (1) according to this embodiment has a configuration in which the solution tank system, which consists of the anode buffer solution tank 123 and the external flow channel 122, etc., in the conventional capillary electrophoresis apparatus shown in Figure 2, is replaced from the conventional structure shown in Figure 3 to the structure shown in Figure 4.

[0085] The anode buffer solution tank 3 is a solution tank that contains the solution, and it contains the solution and air so that a liquid level is formed inside. The lid 11 of the anode buffer solution tank 3 is a lid that closes the opening at the top of the solution tank in which the solution is contained. Inside the anode buffer solution tank 3, electrodes 17 are provided so as to be immersed in the solution contained inside.

[0086] In the solution tank system (1) according to this embodiment, the anode buffer solution tank 3 and its lid 11 are made of transparent acrylic resin so that the internal conditions can be observed. An electrode 17 is pressure-resistant connected to the lid 11 via a ferrule 12. The electrode 17 penetrates the lid 11 from top to bottom and is inserted into the anode buffer solution tank 3. The tip of the electrode 17 is immersed in the anode buffer solution 8-2 contained inside the anode buffer solution tank 3.

[0087] This specification primarily describes a state in which the anode buffer solution 8-2 is contained inside the anode buffer solution tank 3. However, the solution tank system equipped with an endline valve according to this embodiment can be applied to any solution tank. It can also be applied to conditions in which any solution is contained in the solution tank. Similar effects can be obtained even when applied to any solution tank or any solution.

[0088] The anode buffer solution tank 3 is connected to the anode block 118 (see Figure 2) via an internal channel 2-2 and an external channel 2-1. The external channel 2-1 is formed inside the tube 5. For the tube 5, for example, a tube made of tetrafluoroethylene-ethylene copolymer (ETFE) (outer diameter 1 / 16 inch, inner diameter 0.75 mm) can be used.

[0089] In this embodiment, the channel 2-2 inside the anode buffer solution tank 3 formed by the hole 4 is formed inside the bottom of the anode buffer solution tank 3. The channel 2-1 (tube 5) outside the anode buffer solution tank 3 is connected from below to the lower surface of the bottom of the anode buffer solution tank 3.

[0090] The external channel 2-1 (tube 5) is a channel containing the solution and is pressure-resistant connected to the bottom of the anode buffer solution tank 3 via a ferrule 12. The inner end of the external channel 2-1 (tube 5) is connected to the internal channel 2-2 (hole 4) inside the bottom of the anode buffer solution tank 3. It is preferable that the external channel 2-1 (tube 5) is connected to the anode buffer solution tank 3 via a detachable connector or ferrule. For example, a PEEK product can be used as the ferrule 12.

[0091] The external channel 2-1 (tube 5) is a channel that contains the solution and enters the interior of the bottom of the anode buffer solution tank 3 from the outside of the anode buffer solution tank 3, from the bottom surface of the anode buffer solution tank 3. The internal channel 2-2 (hole 4) extends straight vertically upward within the interior of the bottom of the anode buffer solution tank 3, along the extension of the external channel 2-1 (tube 5), and then terminates near the top surface of the bottom of the anode buffer solution tank 3.

[0092] The terminal end of the internal flow path 2-2 (hole 4) widens in an inverse taper shape as it moves from bottom to top. This terminal position marks the boundary between the internal flow path 2-2 (hole 4) and the inside of the anode buffer solution tank 3. An end line valve 7 is formed at this terminal position. The end line valve 7 opens and closes the terminal end of the internal flow path 2-2 (hole 4).

[0093] The external channel 2-1 (tube 5) and the internal channel 2-2 (hole 4) are filled with polymer solution 8-1, which is the separation medium for capillary electrophoresis, during electrophoresis, etc. In this specification, the solutions contained in the external channel 2-1 (tube 5) and the internal channel 2-2 (hole 4) are uniformly polymer solution 8-1. However, the configuration of the solution tank system according to this embodiment can be applied even if the polymer solution is replaced with any other solution. Similar effects can be obtained with any other solution.

[0094] In the structure shown in Figure 4, compared to the conventional structure shown in Figure 3, the internal flow path 2-2 (hole 4) is shorter and straighter, thus simplifying the structure of the anode buffer solution tank 3 and its lid 11. Therefore, these can be easily processed and manufactured at low cost. Furthermore, it is possible to miniaturize the anode buffer solution tank 3. In addition, the internal flow path 2-2 (hole 4) can be easily processed by machining or other methods. Alternatively, the anode buffer solution tank 3 equipped with the internal flow path 2-2 (hole 4) can be injection molded.

[0095] The polymer solution 8-1 inside the channel 2-2 (hole 4) inside the anode buffer solution tank 3 and the anode buffer solution 8-2 contained inside the anode buffer solution tank 3 become one continuous solution at the end of the internal channel 2-2 (hole 4). In reality, the boundary between the two solutions becomes unclear due to diffusion, mixing, etc. However, in the embodiment of the present invention, in order to make the configuration easier to understand, we assume that a boundary between the two solutions exists at the boundary between the internal channel 2-2 (hole 4) and the inside of the anode buffer solution tank 3.

[0096] A pin 13, which forms the valve body, is inserted into the anode buffer solution tank 3. The pin 13 has a head portion 14 with an enlarged outer diameter and a tip portion 15 with a tapered outer diameter. The pin 13 is installed so that the tip portion 15 is pointed vertically downward and penetrates the lid 11, and is positioned so that the tip portion 15 is inside the anode buffer solution tank 3. The pin 13 can be made of, for example, PEEK, and the main body is formed in a cylindrical shape. The outer diameter of the head portion 14 is set to be larger than the outer diameter of the main body of the pin 13. The tip portion 15 is set to be tapered, becoming narrower in diameter from top to bottom.

[0097] The head unit 14 can be coupled to a plunger (not shown) which is driven in one axis direction by a stepping motor (not shown) provided on the main body of the electrophoresis apparatus. The pin 13 can be provided so as to be movable in both vertical and horizontal directions by means of a stepping motor and a link that converts the rotational motion of the stepping motor into linear motion.

[0098] As shown by the arrow in the left diagram of Figure 4, when the head portion 14 is pulled upwards, the tip portion 15 separates from the terminal end of the internal flow path 2-2 (hole 4), and the end line valve 7 enters the "valve open" state. At this time, inside the anode buffer solution tank 3, the tip portion 15 is no longer immersed in the anode buffer solution 8-2.

[0099] Of the analytical steps, step [4] electrophoresis is the step that takes the longest time. The electrophoresis step is performed with the endline valve 7 in the "valve open" position. In other words, in the solution tank system (1) according to this embodiment, the pin 13 is not immersed in the anode buffer solution 8-2 during electrophoresis, similar to the conventional solution tank system (0). This structure makes it possible to avoid the pin 13 having any effect on the electrophoretic analysis.

[0100] On the other hand, as shown by the arrow in the right-hand diagram of Figure 4, when the head portion 14 is pushed downwards, the tip portion 15 closes the terminal end of the internal flow path 2-2 (hole 4), and the end line valve 7 enters the "valve closed" state. At this time, inside the anode buffer solution tank 3, the tip portion 15 is immersed in the anode buffer solution 8-2 and inserted into the terminal portion of the internal flow path 2-2 (hole 4) that widens in an inverse tapered shape. The tip portion 15 then liquid-tightly seals the end of the internal flow path 2-2 (hole 4).

[0101] The inner diameter of the through-hole 20 through which the pin 13 formed in the lid 11 is inserted is made larger than the outer diameter of the main body of the pin 13. Therefore, the solution tank system (1) according to this embodiment has a structure in which a gap exists between the through-hole 20 and the pin 13, similar to the conventional solution tank system (0). With this structure, the inside of the anode buffer solution tank 3, that is, the anode buffer solution 8-2 and air 10 contained in the anode buffer solution tank 3 are maintained at atmospheric pressure, whether the valve is open or closed.

[0102] As is clear from Figure 4, in the solution tank system (1) according to this embodiment, the external flow path 2-1 (tube 5) of the anode buffer solution tank 3 is connected to the bottom side of the anode buffer solution tank 3, and the internal flow path 2-2 (hole 4) of the anode buffer solution tank 3 is provided at the bottom of the anode buffer solution tank 3. The internal flow path 2-2 (hole 4) enters the interior of the bottom wall of the anode buffer solution tank 3 from the outside of the anode buffer solution tank 3 from below, extends vertically upward through the interior of the bottom wall, and widens in an inverse tapered shape toward the interior of the anode buffer solution tank 3 before terminating.

[0103] Therefore, according to the solution tank system (1) of this embodiment, the structure of the anode buffer solution tank and its lid is simplified, making it possible to reduce the size and manufacturing cost, thus solving the above-mentioned <first problem>.

[0104] However, with this structure, the distance (stroke) of the pin 13 moves when switching between "valve open" and "valve closed" becomes large. As a result, the volume change of the portion of the pin 13 immersed in the buffer solution 8-2 becomes large when the endline valve 7 is opened and closed, and the change in the liquid level 9 of the buffer solution 8-2 becomes large. In this state, the difference in liquid level between the anode and cathode sides of the buffer solution becomes large, and there is a risk that the polymer solution 8-1 inside the capillary will move due to gravity during electrophoresis. In addition, because the stroke of the pin 13 is large, when the pin 13 is moved downward, the central axis of the pin 13 tilts with respect to the vertical, and there is a risk that the tip 15 of the pin 13 will reach a position far from the end of the internal flow path 2-2 (hole 4), preventing the "valve from closing". Furthermore, in order to achieve a large stroke of the pin 13, it is necessary to use a costly stepping motor instead of a solenoid actuator. These points can be resolved in the solution tank system (2) and later forms equipped with an endline valve according to the embodiment of the present invention.

[0105] Figure 5 shows a configuration in which the electrode has been removed from a solution tank system (1) equipped with an endline valve according to an embodiment of the present invention. Figure 5 shows a structure in which the electrode 17, the through hole for connecting the electrode 17 to the lid 11, and the ferrule 12 have been removed from the structure of the solution tank system (1) equipped with an endline valve shown in Figure 4. For solution tanks in which electrophoresis is not performed, a simpler structure may be used, as shown in Figure 5. The same effects as in Figure 4 can be obtained with the structure shown in Figure 5.

[0106] <Solution tank system (2) equipped with an endline valve according to an embodiment of the present invention> Figure 6 is a diagram showing the configuration of a solution tank system (2) equipped with an endline valve according to an embodiment of the present invention. Figure 6 shows the cross-sectional structure of an anode buffer solution tank and its lid, which is equipped with an endline valve on the bottom side. The left diagram of Figure 6 shows the "valve open" state. The right diagram of Figure 6 shows the "valve closed" state.

[0107] The solution tank system (2) according to this embodiment includes an anode buffer solution tank 3, its lid 11, an end line valve 7, an external flow path 2-1 of the anode buffer solution tank 3, an internal flow path 2-2 of the anode buffer solution tank 3, and so on. Compared to the solution tank system (1) with an end line valve shown in Figure 4, the solution tank system (2) according to this embodiment changes the position of the pin 13 when the end line valve 7 is in the "valve open" state, without changing the components. Some explanations of parts that are unchanged from Figure 4 are omitted.

[0108] In the left diagram of Figure 4, the end line valve 7 is in the "valve open" position, and the tip 15 is not immersed in the anode buffer solution 8-2. In contrast, in the left diagram of Figure 6, the end line valve 7 is in the "valve open" position, and the tip 15 is immersed in the anode buffer solution 8-2. In the left diagram of Figure 6, the tip 15 is close to the upper surface of the bottom of the anode buffer solution tank 3, i.e., close to the end line valve 7.

[0109] Preferably, the tip portion 15 is designed to descend to at least between the midpoint of the interior of the anode buffer solution tank 3 and the upper surface of the bottom of the anode buffer solution tank 3 when the end line valve 7 is in the "valve open" position. For example, the tip portion 15 can be designed to descend to the same height as the upper surface of the bottom of the anode buffer solution tank 3.

[0110] According to this embodiment of the solution tank system (2), since it has the same structure as the solution tank system (1), the above-mentioned <first problem> can be solved.

[0111] Furthermore, according to the solution tank system (2) of this embodiment, the travel distance (stroke) of the pin 13 is reduced when switching between "valve open" and "valve closed". When the endline valve 7 is opened and closed, the volume change of the portion of the pin 13 immersed in the anode buffer solution 8-2 is reduced, and the change in the height of the liquid level 9 of the anode buffer solution 8-2 is reduced. In this state, the difference in the liquid levels of the two buffer solutions on the anode side and the cathode side becomes smaller, making it difficult for the polymer solution 8-1 inside the capillary to move due to the difference in hydrostatic head during electrophoresis.

[0112] Furthermore, because the stroke of pin 13 is kept small, pin 13 can be moved with a low-cost solenoid actuator, as in the case of Figure 3, instead of a stepping motor, as in the case of Figure 4. Also, because the stroke of pin 13 is kept small, the risk of the tip 15 of pin 13 coming out of the end of the internal flow path 2-2 (hole 4) and failing to "close the valve" when moving pin 13 downwards can be reduced.

[0113] However, since pin 13 is immersed in anode buffer solution 8-2 during electrophoresis, there are concerns about the influence of pin 13 on the electrophoretic analysis. However, when electrophoretic analysis was actually performed according to the structure in Figure 6, it was found that the influence of pin 13 being immersed in anode buffer solution 8-2 on the electrophoretic analysis was small. Therefore, it was found that the structure in Figure 6 is superior to the structure in Figure 4.

[0114] <Solution tank system (3) equipped with an endline valve according to an embodiment of the present invention> Figure 7 is a diagram showing the configuration of a solution tank system (3) equipped with an endline valve according to an embodiment of the present invention. Figure 7 shows the cross-sectional structure of an anode buffer solution tank and its lid, which is equipped with an endline valve on the bottom side. The left diagram of Figure 7 shows the "valve open" state. The right diagram of Figure 7 shows the "valve closed" state.

[0115] The solution tank system (3) according to this embodiment includes an anode buffer solution tank 3, its lid 11, an end line valve 7, an external flow path 2-1 of the anode buffer solution tank 3, an internal flow path 2-2 of the anode buffer solution tank 3, and so on. Compared to the solution tank system (2) with an end line valve shown in Figure 6, the solution tank system (3) according to this embodiment further changes the position of the pin 13 when the end line valve 7 is in the "valve open" state, without changing the components. Some explanations of parts that are unchanged from Figure 6 are omitted.

[0116] In the left diagram of Figure 7, the position of the tip 15 of the end line valve 7 when it is in the "valve open" state is designed to be lower than the position of the tip 15 in the "valve open" state shown in the left diagram of Figure 6. In the left diagram of Figure 7, a portion of the tip 15 of the end line valve 7 when it is in the "valve open" state is inserted inside the inverted tapered terminal end of the internal flow path 2-2 (hole 4).

[0117] According to this embodiment of the solution tank system (3), since it has the same structure as the solution tank system (1), the above-mentioned <first problem> can be solved.

[0118] Furthermore, according to the solution tank system (3) of this embodiment, when moving the pin 13 downward to switch from "valve open" to "valve closed," the risk of the tip 15 of the pin 13 coming off the end of the internal flow path 2-2 (hole 4) and failing to achieve the "valve closed" state can be reduced to almost zero. Even if, in the "valve open" state shown in the left diagram of Figure 7, the central axis of the pin 13 and the central axis of the internal flow path 2-2 (hole 4) are misaligned, the tapered tip 15 is guided by the reverse tapered portion of the internal flow path 2-2 (hole 4), so that the tip 15, which is trying to descend, is corrected to move towards the center of the internal flow path 2-2 (hole 4).

[0119] <Solution tank system (4) equipped with an endline valve according to an embodiment of the present invention> Figure 8 is a diagram showing the configuration of a solution tank system (4) equipped with an endline valve according to an embodiment of the present invention. Figure 8 shows the cross-sectional structure of an anode buffer solution tank and its lid, which is equipped with an endline valve on the bottom side. The left diagram of Figure 8 shows the "valve open" state. The right diagram of Figure 8 shows the "valve closed" state.

[0120] The solution tank system (4) according to this embodiment includes an anode buffer solution tank 3, its lid 11, an end line valve 7, an external flow path 2-1 of the anode buffer solution tank 3, an internal flow path 2-2 of the anode buffer solution tank 3, and so on. Compared to the solution tank system (3) equipped with an end line valve shown in Figure 7, the solution tank system (4) according to this embodiment has some modified components. The explanation of parts that remain unchanged from those in Figure 7 will be partially omitted.

[0121] In Figure 8, an O-ring 16-2 is installed on the inside of the upper end of the side wall of the anode buffer solution tank 3. When the anode buffer solution tank 3 and the lid 11 are joined together, the O-ring 16-2 is compressed between the anode buffer solution tank 3 and the lid 11, sealing the gap between the anode buffer solution tank 3 and the lid 11.

[0122] The pin 13 has a shape with an enlarged diameter portion 22 on the side of its main body. The enlarged diameter portion 22 is provided in a shape that is larger in outer diameter than the main body. An O-ring 16-3 is installed on the upper surface of the enlarged diameter portion 22. The enlarged diameter portion 22 is located below the lid 11. The outer diameter of the enlarged diameter portion 22 is set to be larger than the outer diameter of the main body of the pin 13 and larger than the inner diameter of the through hole 20 of the lid 11. Therefore, the enlarged diameter portion 22 will not come out of the through hole 20. The outer diameter of the O-ring 16-3 is set to be larger than the inner diameter of the through hole 20 and smaller than the outer diameter of the enlarged diameter portion 22.

[0123] When the actuator moves the pin 13 upward (pulling the head portion 14), the O-ring 16-3 is sandwiched between the upper surface of the enlarged diameter portion 22 and the lower surface of the cover 11, and the O-ring 16-3 is compressed. At this time, as shown in the left diagram of Figure 8, the tip portion 15 moves away from the end of the internal flow path 2-2 (hole 4), so the end line valve 7 enters the "valve open" state, and at the same time, the compression of the O-ring 16-3 seals the gap between the pin 13 and the through hole 20.

[0124] Therefore, when the endline valve 7 is in the "valve open" position, the anode buffer solution tank 3 is sealed. By maintaining this state, even if the electrophoresis apparatus is subjected to vibration or the external air pressure changes during transport, the risk of the anode buffer solution 8-2 leaking out of the anode buffer solution tank 3 can be avoided.

[0125] On the other hand, the tip portion 15 tapers, becoming narrower in diameter from top to bottom. As shown in the right diagram of Figure 8, when the actuator moves the pin 13 downward (by pushing the head portion 14), the tip portion 15 is inserted into the end of the internal flow path 2-2 (hole 4), which widens in the reverse taper shape, and the tip portion 15 closes the end of the internal flow path 2-2 (hole 4), resulting in a "valve closed" state. At this time, the upper surface of the enlarged diameter portion 22 and the O-ring 16-3 separate from the lower surface of the lid 11, so the gap between the pin 13 and the through hole 20 is no longer sealed, and the inside of the anode buffer solution tank 3 is opened to the atmosphere.

[0126] The solution tank system (4) according to this embodiment has the same structure as the solution tank system (1), and therefore the above-mentioned <first problem> can be solved. Furthermore, since the anode buffer solution tank 3 is sealed when the end line valve 7 is in the "valve open" state, the above-mentioned <second problem> to <third problem> can be solved.

[0127] <Solution tank system (5) equipped with an endline valve according to an embodiment of the present invention> Figure 9 is a diagram showing the configuration of a solution tank system (5) equipped with an endline valve according to an embodiment of the present invention. Figure 9 shows the cross-sectional structure of an anode buffer solution tank and its lid, which is equipped with an endline valve on the bottom side. The left diagram of Figure 9 shows the "valve open" state. The right diagram of Figure 9 shows the "valve closed" state.

[0128] The solution tank system (5) according to this embodiment includes an anode buffer solution tank 3, its lid 11, an end line valve 7, an external flow path 2-1 of the anode buffer solution tank 3, an internal flow path 2-2 of the anode buffer solution tank 3, and so on. Compared to the solution tank system (3) equipped with an end line valve shown in Figure 7, the solution tank system (5) according to this embodiment has some modified components. The explanation of parts that remain unchanged from Figure 7 is partially omitted.

[0129] In Figure 9, an O-ring 16-2 is installed on the inside of the upper end of the side wall of the anode buffer solution tank 3. When the anode buffer solution tank 3 and the lid 11 are joined together, the O-ring 16-2 is compressed between the anode buffer solution tank 3 and the lid 11, sealing the gap between the anode buffer solution tank 3 and the lid 11.

[0130] The pin 13 is provided with a shape that includes an enlarged diameter portion 22 on the side of the main body that enlarges the outer diameter of the pin 13. An O-ring 16-4 is installed on the lower surface of the enlarged diameter portion 22. The enlarged diameter portion 22 is located above the lid 11. The outer diameter of the enlarged diameter portion 22 is set to be larger than the outer diameter of the main body of the pin 13 and larger than the inner diameter of the through hole 20 of the lid 11. Therefore, the enlarged diameter portion 22 is not inserted into the through hole 20. The outer diameter of the O-ring 16-4 is set to be larger than the inner diameter of the through hole 20 and smaller than the outer diameter of the enlarged diameter portion 22.

[0131] When the actuator moves the pin 13 downward (pushing the head portion 14), the O-ring 16-4 is sandwiched between the lower surface of the enlarged diameter portion 22 and the upper surface of the lid 11, and the O-ring 16-4 is compressed. At this time, as shown in the right diagram of Figure 9, the tip portion 15 closes the end of the internal flow path 2-2 (hole 4), and the end line valve 7 enters the "valve closed" state, and at the same time, the gap between the pin 13 and the through hole 20 is sealed by the O-ring 16-4. In addition, the gap between the anode buffer solution tank 3 and the lid 11 is sealed by the O-ring 16-2.

[0132] Therefore, when the endline valve 7 is in the "valve closed" position, the anode buffer solution tank 3 is sealed. By maintaining this state, even if the electrophoresis apparatus is subjected to vibration or the ambient pressure changes during transport, the risk of the anode buffer solution 8-2 leaking out of the anode buffer solution tank 3 can be avoided.

[0133] On the other hand, when the actuator moves the pin 13 upward (pulls the head portion 14), as shown in the left diagram of Figure 9, the lower surface of the enlarged diameter portion 22 separates from the upper surface of the lid 11, so that the gap between the pin 13 and the through hole 20 is no longer sealed, and the inside of the anode buffer solution tank 3 is opened to the atmosphere. At the same time, the tip portion 15 separates from the terminal end of the internal flow path 2-2 (hole 4), resulting in an "open valve" state.

[0134] The solution tank system (5) according to this embodiment has the same structure as the solution tank system (1), and therefore the above-mentioned <first problem> can be solved. Furthermore, since the anode buffer solution tank 3 is sealed when the end line valve 7 is in the "valve closed" state, the above-mentioned <second problem> to <third problem> can be solved.

[0135] <Solution tank system (6) equipped with an endline valve according to an embodiment of the present invention> Figure 10 is a diagram showing the configuration of a solution tank system (6) equipped with an endline valve according to an embodiment of the present invention. Figure 10 shows the cross-sectional structure of an anode buffer solution tank and its lid, which is equipped with an endline valve on the bottom side. The left diagram of Figure 10 shows the "valve open" state. The right diagram of Figure 10 shows the "valve closed" state.

[0136] The solution tank system (6) according to this embodiment includes an anode buffer solution tank 3, its lid 11, an end line valve 7, an external flow path 2-1 of the anode buffer solution tank 3, an internal flow path 2-2 of the anode buffer solution tank 3, and so on. Compared to the solution tank system (3) equipped with an end line valve shown in Figure 7, the solution tank system (6) according to this embodiment has some modified components. The explanation of parts that remain unchanged from those in Figure 7 will be partially omitted.

[0137] In Figure 10, an O-ring 16-2 is installed on the inside of the upper end of the side wall of the anode buffer solution tank 3. When the anode buffer solution tank 3 and the lid 11 are joined together, the O-ring 16-2 is compressed between the anode buffer solution tank 3 and the lid 11, sealing the gap between the anode buffer solution tank 3 and the lid 11.

[0138] An O-ring 16-5 is installed on the side of the pin 13 that is located inside the through-hole 20 of the lid 11. The O-ring 16-5 is compressed between the side of the pin 13 and the inner surface of the through-hole 20. Even when the pin 13 moves vertically, that is, whether the end line valve 7 is in the "open" state, the "closed" state, or an intermediate opening state, the compressed state of the O-ring 16-5 is maintained. Maintaining this compressed state ensures that the gap between the pin 13 and the through-hole 20 is always sealed.

[0139] Furthermore, the gap between the anode buffer solution tank 3 and the lid 11 is sealed by the O-ring 16-2. As a result, the anode buffer solution tank 3 is sealed. By maintaining this state, even if the electrophoresis apparatus is subjected to vibration or the external air pressure changes during transport, the risk of the anode buffer solution 8-2 leaking out of the anode buffer solution tank 3 can be avoided.

[0140] On the other hand, the tip portion 15 tapers, becoming narrower in diameter from top to bottom. As shown in the right diagram of Figure 10, when the actuator moves the pin 13 downward (by pushing the head portion 14), the tip portion 15 is inserted into the end of the internal flow path 2-2 (hole 4), which widens in an inverse taper, and the tip portion 15 closes the end of the internal flow path 2-2 (hole 4), resulting in a "valve closed" state. At this time, since the O-ring 16-5 is located inside the through hole 20, the gap between the pin 13 and the through hole 20 remains sealed, and the inside of the anode buffer solution tank 3 is not released to the atmosphere through the through hole 20.

[0141] In contrast, when the actuator moves the pin 13 upward (pulling the head portion 14), as shown in the left diagram of Figure 10, the tip portion 15 moves away from the end of the internal flow path 2-2 (hole 4), resulting in an "open valve" state. However, even in this case, since the O-ring 16-5 is located inside the through-hole 20, the gap between the pin 13 and the through-hole 20 remains sealed, and the inside of the anode buffer solution tank 3 is not released to the atmosphere through the through-hole 20.

[0142] The solution tank system (6) according to this embodiment has the same structure as the solution tank system (1), and therefore solves the above-mentioned <first problem>. Furthermore, since the anode buffer solution tank 3 is sealed regardless of whether the end line valve 7 is in the "valve open," "valve closed," or intermediate state, the above-mentioned <second problem> to <third problem> can be solved.

[0143] <Solution tank system (7) equipped with an endline valve according to an embodiment of the present invention> Figure 11 is a diagram showing the configuration of a solution tank system (7) equipped with an endline valve according to an embodiment of the present invention. Figure 11 shows the cross-sectional structure of an anode buffer solution tank and its lid, which is equipped with an endline valve on the bottom side. The left diagram of Figure 11 shows the "valve open" state. The right diagram of Figure 11 shows the "valve closed" state.

[0144] The solution tank system (7) according to this embodiment includes an anode buffer solution tank 3, its lid 11, an end line valve 7, an external flow path 2-1 of the anode buffer solution tank 3, an internal flow path 2-2 of the anode buffer solution tank 3, and so on. Compared to the solution tank system (4) equipped with an end line valve shown in Figure 8, the solution tank system (7) according to this embodiment has some modified components. The explanation of parts that remain unchanged from Figure 8 is partially omitted.

[0145] In Figure 11, in addition to the configuration shown in Figure 8, external channels 2-3 are pressure-resistant connected to the upper surface of the lid 11 via the ferrule 12. The external channels 2-3 are formed inside the tube 5. For the tube 5, for example, a tube made of tetrafluoroethylene-ethylene copolymer (ETFE) (outer diameter 1 / 16 inch, inner diameter 0.75 mm) can be used.

[0146] The external channel 2-3 (tube 5) connected to the lid 11 is an air-filled channel that enters the inside of the lid 11 from outside the anode buffer solution tank 3. The external channel 2-3 (tube 5) connected to the lid 11 communicates with the inside of the anode buffer solution tank 3 via the internal channel 2-4 formed as a hole 4 inside the lid 11, and terminates inside the anode buffer solution tank 3.

[0147] The external channel 2-3 (tube 5) connected to the lid 11 is connected to air 10 at atmospheric pressure. The external channel 2-3 (tube 5) connected to the lid 11 can supply air 10 at atmospheric pressure into the anode buffer solution tank 3. Therefore, at the terminal end of the external channel 2-3 (tube 5) connected to the lid 11, the air inside the anode buffer solution tank 3 and the air in the external channel 2-3 (tube 5) merge. As a result, the inside of the anode buffer solution tank 3 is constantly maintained at atmospheric pressure.

[0148] When the actuator moves the pin 13 upward (pulls the head portion 14), the O-ring 16-3 is sandwiched between the upper surface of the enlarged diameter portion 22 and the lower surface of the cover 11, and the O-ring 16-3 is compressed. At this time, as shown in the left diagram of Figure 11, the tip portion 15 moves away from the end of the internal flow path 2-2 (hole 4), so that the end line valve 7 is in the "valve open" state, and at the same time, the gap between the pin 13 and the through hole 20 is sealed by the O-ring 16-3.

[0149] Therefore, when the endline valve 7 is in the "valve open" state, the inside of the anode buffer solution tank 3 is connected to atmospheric air 10 via the external flow path 2-3 (tube 5) connected to the lid 11. The inner diameter of the external flow path 2-3 (tube 5) connected to the lid 11 is set to be relatively small. Therefore, in this state, the possibility of the anode buffer solution 8-2 inside the anode buffer solution tank 3 leaking out through the external flow path 2-3 (tube 5) connected to the lid 11 is reduced. In other words, by maintaining this state, even if the electrophoresis apparatus is subjected to vibration or the external air pressure changes when the electrophoresis apparatus is transported, the risk of the anode buffer solution 8-2 leaking out of the anode buffer solution tank 3 can be avoided.

[0150] On the other hand, the tip portion 15 tapers, becoming narrower in diameter from top to bottom. As shown in the right diagram of Figure 11, when the actuator moves the pin 13 downward (by pushing the head portion 14), the tip portion 15 is inserted into the end of the internal flow path 2-2 (hole 4), which widens in the reverse taper shape, and the tip portion 15 closes the end of the internal flow path 2-2 (hole 4), resulting in a "valve closed" state. At this time, the upper surface of the enlarged diameter portion 22 and the O-ring 16-3 separate from the lower surface of the lid 11, so the gap between the pin 13 and the through hole 20 is no longer sealed. The inside of the anode buffer solution tank 3 is maintained at atmospheric pressure even when the end line valve 7 is closed.

[0151] The solution tank system (7) according to this embodiment has the same structure as the solution tank system (1), and therefore the above-mentioned <first problem> can be solved. Furthermore, since the anode buffer solution tank 3 is sealed regardless of whether the endline valve 7 is in the "valve open," "valve closed," or intermediate state, the above-mentioned <second problem> to <third problem> can be solved.

[0152] <Solution tank system (8) equipped with an endline valve according to an embodiment of the present invention> Figure 12 is a diagram showing the configuration of a solution tank system (8) equipped with an endline valve according to an embodiment of the present invention. Figure 12 shows the cross-sectional structure of an anode buffer solution tank and its lid, which is equipped with an endline valve on the bottom side. The left diagram of Figure 12 shows the "valve open" state. The right diagram of Figure 12 shows the "valve closed" state.

[0153] The solution tank system (8) according to this embodiment includes an anode buffer solution tank 3, its lid 11, an end line valve 7, an external flow path 2-1 of the anode buffer solution tank 3, an internal flow path 2-2 of the anode buffer solution tank 3, and so on. Compared to the solution tank system (7) equipped with an end line valve shown in Figure 11, the solution tank system (8) according to this embodiment has some modified components. The explanation of parts that remain unchanged from Figure 11 is partially omitted.

[0154] In Figure 12, in addition to the configuration shown in Figure 11, a valve 23-1 is installed on the external flow path 2-3 (tube 5) connected to the lid 11. When valve 23-1 is opened, the external flow path 2-3 (tube 5) is connected to the outside under atmospheric pressure, allowing atmospheric air 10 to flow into the anode buffer solution tank 3. On the other hand, when valve 23-1 is closed, the external flow path 2-3 (tube 5) is isolated from the outside under atmospheric pressure, allowing the anode buffer solution tank 3 to be sealed.

[0155] Therefore, as shown in the left diagram of Figure 12, opening the endline valve 7 and closing valve 23-1 seals the anode buffer solution tank 3. By maintaining this state, even if the electrophoresis apparatus is subjected to vibration or the ambient pressure changes during transport, the risk of the anode buffer solution 8-2 leaking out of the anode buffer solution tank 3 can be avoided.

[0156] The solution tank system (8) according to this embodiment has the same structure as the solution tank system (1), and therefore solves the above-mentioned <first problem>. Furthermore, when the end line valve 7 is in the "valve open" state, the anode buffer solution tank 3 is sealed by closing the valve 23-1 on the external flow path 2-3 (tube 5), thus solving the above-mentioned <second problem> to <third problem>. Moreover, the sealing and opening of the anode buffer solution tank 3 can be actively switched by operating the valve 23-1.

[0157] <Solution tank system (9) equipped with an endline valve according to an embodiment of the present invention> Figure 13 is a diagram showing the configuration of a solution tank system (9) equipped with an endline valve according to an embodiment of the present invention. Figure 13 shows the cross-sectional structure of an anode buffer solution tank and its lid, which is equipped with an endline valve on the bottom side. The left diagram of Figure 13 shows the "valve open" state. The right diagram of Figure 13 shows the "valve closed" state.

[0158] The solution tank system (9) according to this embodiment includes an anode buffer solution tank 3, its lid 11, an end line valve 7, an external flow path 2-1 of the anode buffer solution tank 3, an internal flow path 2-2 of the anode buffer solution tank 3, and so on. Compared to the solution tank system (7) with an end line valve shown in Figure 11, the solution tank system (9) according to this embodiment has some modified components. The explanation of parts that are unchanged from Figure 11 will be partially omitted.

[0159] In Figure 13, in addition to the configuration shown in Figure 11, the end of the external flow path 2-3 (tube 5) connected to the lid 11, opposite to the lid 11, is connected to an air source (not shown). The air source supplies pressure-controlled air 19. The inside of the anode buffer solution tank 3 can be filled by supplying pressure-controlled air 19. The air source can also supply atmospheric air 10 instead of pressure-controlled air 19. The external flow path 2-3 (tube 5) connected to the lid 11 and the supply path for supplying pressure-controlled air 19 may be equipped with valves to adjust the flow rate of air 19.

[0160] When the actuator moves the pin 13 upward (pulling the head portion 14), the O-ring 16-3 is sandwiched between the upper surface of the enlarged diameter portion 22 and the lower surface of the cover 11, and the O-ring 16-3 is compressed. At this time, as shown in the left diagram of Figure 13, the tip portion 15 moves away from the end of the internal flow path 2-2 (hole 4), so that the end line valve 7 is in the "valve open" state, and at the same time, the gap between the pin 13 and the through hole 20 is sealed by the O-ring 16-3.

[0161] Therefore, when the endline valve 7 is in the "valve open" state, the anode buffer solution tank 3 is sealed. In this state, when pressure-controlled air 19 is supplied to the inside of the anode buffer solution tank 3 through the external flow path 2-3 (tube 5) connected to the lid 11, the inside of the anode buffer solution tank 3 can be replaced with pressure-controlled air 19. In other words, it becomes possible to control the pressure inside the anode buffer solution tank 3. At this time, the pressure of the anode buffer solution 8-2 contained in the anode buffer solution tank 3, and the pressure of the polymer solution 8-1 filled in the internal flow path 2-2 (hole 4) and the external flow path 2-1 (tube 5) become the same as the pressure of the pressure-controlled air 19. Thus, the pressure difference between both ends of the capillary 101 can be controlled.

[0162] The air source connected to the external flow path 2-3 (tube 5) can also supply atmospheric air 10 instead of pressure-controlled air 19. The external flow path 2-3 (tube 5) connected to the lid 11 and the supply path for supplying pressure-controlled air 19 may be equipped with a valve to adjust the flow rate of air 19. By closing this valve, the external flow path 2-3 (tube 5) can be sealed, and the anode buffer solution tank 3 can be completely sealed.

[0163] Sealing the anode buffer solution tank 3 has the following effects in addition to pressure control: It prevents the anode buffer solution 8-2 inside the anode buffer solution tank 3 from leaking out when the electrophoresis apparatus is transported or placed in a harsh environment. It also reduces the risk of the anode buffer solution 8-2 leaking out from the external channel 2-3 (tube 5). Leakage of the anode buffer solution 8-2 can not only contaminate the surroundings but also make subsequent analysis impossible. However, sealing the anode buffer solution tank 3 reduces this risk. Furthermore, sealing the anode buffer solution tank 3 can reduce the risk of discharge occurring from the anode buffer solution tank 3 to the outside when a high voltage is applied to the electrode 17.

[0164] As shown in the left diagram of Figure 13, when the actuator moves the pin 13 downward (by pushing the head portion 14), the tip portion 15 is inserted into the end of the internal flow path 2-2 (hole 4) which widens in an inverse tapered shape, and the tip portion 15 closes the end of the internal flow path 2-2 (hole 4), resulting in a "valve closed" state. At this time, the upper surface of the enlarged diameter portion 22 and the O-ring 16-3 separate from the lower surface of the lid 11, so the gap between the pin 13 and the through hole 20 is no longer sealed. The inside of the anode buffer solution tank 3 is open to the atmosphere and filled with atmospheric pressure air 10. At this time, the valve of the air source can be closed, or the air source can be supplied with atmospheric pressure air 10.

[0165] The solution tank system (9) according to this embodiment has the same structure as the solution tank system (1), and therefore the above-mentioned <first problem> can be solved. Furthermore, since the anode buffer solution tank 3 is sealed when the end line valve 7 is in the "valve open" state, the above-mentioned <second problem> to <third problem> can be solved. In addition, since pressure-controlled air 19 or atmospheric pressure air 10 can be supplied to the anode buffer solution tank 3 from the outside, the pressure difference between both ends of the capillary 101 can be freely controlled.

[0166] <Solution tank system (10) equipped with an endline valve according to an embodiment of the present invention> Figure 14 is a diagram showing the configuration of a solution tank system (10) equipped with an endline valve according to an embodiment of the present invention. Figure 14 shows the cross-sectional structure of an anode buffer solution tank and its lid, which is equipped with an endline valve on the bottom side. The left diagram of Figure 14 shows the "valve open" state. The right diagram of Figure 14 shows the "valve closed" state.

[0167] The solution tank system (10) according to this embodiment includes an anode buffer solution tank 3, its lid 11, an end line valve 7, an external flow path 2-1 of the anode buffer solution tank 3, an internal flow path 2-2 of the anode buffer solution tank 3, and so on. Compared to the solution tank system (9) with an end line valve shown in Figure 13, the solution tank system (10) according to this embodiment has some modified components. The explanation of parts that are unchanged from Figure 13 will be partially omitted.

[0168] In Figure 14, in addition to the configuration shown in Figure 13, the external flow path 2-3 (tube 5) connected to the lid 11 branches in two directions. One branch is connected to an air source (not shown) that supplies pressure-controlled air 19. The other branch is connected to the outside where atmospheric air 10 exists. Furthermore, a valve 23-2 is installed on the external flow path 2-3 (tube 5) connected to the lid 11, between the branching point and the air source. Also, a valve 23-3 is installed between the branching point and the outside where atmospheric air 10 exists.

[0169] When the actuator moves the pin 13 upward (pulls the head portion 14), the O-ring 16-3 is sandwiched between the upper surface of the enlarged diameter portion 22 and the lower surface of the cover 11, and the O-ring 16-3 is compressed. At this time, as shown in the left diagram of Figure 14, the tip portion 15 moves away from the end of the internal flow path 2-2 (hole 4), so that the end line valve 7 is in the "valve open" state, and at the same time, the gap between the pin 13 and the through hole 20 is sealed by the O-ring 16-3.

[0170] In this state, opening valve 23-2 and closing valve 23-3 allows pressure-controlled air 19 to be supplied to the inside of the anode buffer solution tank 3 through the external flow path 2-3 (tube 5) connected to the lid 11. By supplying air 19, the inside of the anode buffer solution tank 3 can be replaced with pressure-controlled air 19. In other words, it becomes possible to control the pressure inside the anode buffer solution tank 3. At this time, the pressure of the anode buffer solution 8-2 contained in the anode buffer solution tank 3, as well as the pressure of the polymer solution 8-1 contained in the internal flow path 2-2 (hole 4) and the external flow path 2-1 (tube 5), will be the same as the pressure of the pressure-controlled air 19. Therefore, the pressure difference between both ends of the capillary 101 can be controlled.

[0171] The air source connected to the external flow path 2-3 (tube 5) can also supply atmospheric air 10 instead of pressure-controlled air 19. Alternatively, valve 23-2 can be closed and valve 23-3 opened to supply atmospheric air 10 into the anode buffer solution tank 3 through the external flow path 2-3 (tube 5). By supplying air 10, the inside of the anode buffer solution tank 3 can be replaced with atmospheric air 10.

[0172] On the other hand, closing both valves 23-2 and 23-3 seals the anode buffer solution tank 3. Sealing the anode buffer solution tank 3 has the following effects: It prevents the anode buffer solution 8-2 inside the anode buffer solution tank 3 from leaking out when the electrophoresis apparatus is transported or placed in a harsh environment. It also reduces the risk of the anode buffer solution 8-2 leaking out from the external channel 2-3 (tube 5). Leakage of the anode buffer solution 8-2 can not only contaminate the surroundings but also make subsequent analysis impossible. However, sealing the anode buffer solution tank 3 reduces this risk. Furthermore, sealing the anode buffer solution tank 3 can reduce the risk of discharge occurring from the anode buffer solution tank 3 to the outside when a high voltage is applied to the electrode 17.

[0173] As shown in the right-hand diagram of Figure 14, when the actuator moves the pin 13 downward (by pushing the head portion 14), the tip portion 15 is inserted into the end of the internal flow path 2-2 (hole 4), which widens in an inverse tapered shape, and the tip portion 15 closes the end of the internal flow path 2-2 (hole 4), resulting in a "valve closed" state. At this time, the upper surface of the enlarged diameter portion 22 and the O-ring 16-3 separate from the lower surface of the lid 11, so the gap between the pin 13 and the through hole 20 is no longer sealed. The inside of the anode buffer solution tank 3 is opened to the atmosphere and filled with atmospheric pressure air 10. At this time, the valve 23-2 is closed and the valve 23-3 is opened, connecting the inside of the anode buffer solution tank 3 to the outside where atmospheric pressure air 10 exists via the external flow path 2-3 (tube 5).

[0174] The solution tank system (10) according to this embodiment has the same structure as the solution tank system (1), and therefore solves the above-mentioned <first problem>. Furthermore, when the end line valve 7 is in the "valve open" state, the anode buffer solution tank 3 is sealed by closing valve 23-3, thus solving the above-mentioned <second problem> to <third problem>. In addition, since pressure-controlled air 19 or atmospheric air 10 can be supplied to the anode buffer solution tank 3 from the outside by operating valves 23-2 and 23-3, the pressure difference between both ends of the capillary 101 can be freely controlled.

[0175] <Solution tank system (11) equipped with an endline valve according to an embodiment of the present invention> Figure 15 is a diagram showing the configuration of a solution tank system (11) equipped with an endline valve according to an embodiment of the present invention. Figure 15 shows the cross-sectional structure of an anode buffer solution tank and its lid, which is equipped with an endline valve on the bottom side. The left diagram of Figure 15 shows the "valve open" state. The right diagram of Figure 15 shows the "valve closed" state.

[0176] The solution tank system (11) according to this embodiment includes an anode buffer solution tank 3, its lid 11, an end line valve 7, an external flow path 2-1 of the anode buffer solution tank 3, an internal flow path 2-2 of the anode buffer solution tank 3, and so on. Compared to the solution tank system (2) with an end line valve shown in Figure 6, the solution tank system (11) according to this embodiment has some modified components. The explanation of parts that are unchanged from Figure 6 is partially omitted.

[0177] A spring 18 is mounted between the lower surface of the head portion 14 and the upper surface of the lid 11 in a compressed state, shortened to its natural length, and positioned coaxially with the pin 13. A compressed coil spring can be installed as the spring 18. The outer diameter of the spring 18 is smaller than the outer diameter of the head portion 14 and larger than the inner diameter of the through hole 20. Therefore, the spring 18 is held between the lower surface of the head portion 14 and the upper surface of the lid 11 in a state that allows for elastic extension and compression.

[0178] Therefore, when no external force is applied to the pin 13, the pin 13 is biased upward by the force of the spring 18 and can move upward to a position where the upper surface of the enlarged diameter portion 22 and the lower surface of the lid 11 come into contact. When the pin 13 moves upward, as shown in the left diagram of Figure 15, the tip portion 15 moves away from the end of the internal flow path 2-2 (hole 4), so the end line valve 7 is in the "valve open" state. However, because there is a gap between the pin 13 and the through hole 20, the inside of the anode buffer solution tank 3 remains filled with air 10 at atmospheric pressure.

[0179] As shown in the right diagram of Figure 15, when the pin 13 is moved downward (the head portion 14 is pushed), the tip portion 15 is inserted into the end of the internal flow path 2-2 (hole 4), which widens in an inverse tapered shape, and the tip portion 15 closes the end of the internal flow path 2-2 (hole 4), resulting in a "valve closed" state. In this state, when the force that moved the pin 13 downward is released (the head portion 14 is released), the pin 13 moves upward due to the elastic restoring force of the spring 18 and returns to its original position, resulting in the "valve open" state shown in the left diagram of Figure 15.

[0180] The solution tank system (11) according to this embodiment has the same structure as the solution tank system (1), and therefore the above-mentioned <first problem> can be solved. Furthermore, as will be explained below, the degree of freedom in selecting actuators is improved, and therefore the above-mentioned <fourth problem> can be solved. Accordingly, the solution tank system equipped with an endline valve can be made less expensive.

[0181] In the configuration shown in Figure 6, the actuator needs to move the pin 13 in both up and down directions, so a structure that fixes the actuator to each other or an interlocking structure is required between the actuator and the head portion 14. In contrast, in the configuration shown in Figure 15, the actuator only needs to move the pin 13 downwards, so a structure that fixes the actuator to each other or an interlocking structure is not required between the actuator and the pin 13.

[0182] Forming these structures requires mechanisms and effort. Eliminating these requirements simplifies electrophoresis apparatuses, reducing manufacturing costs and analytical effort. This effect is particularly significant when replacing the solution tank system while maintaining and reusing actuators, and becomes even greater when the replacement frequency is high.

[0183] Instead of a solenoid actuator, any other actuator, such as a stepping motor, may be used to drive the pin 13. For example, using an air cylinder can reduce the cost of the device. As shown in Figure 15, the vertical travel distance (stroke) of the pin 13 is relatively short, so a small air cylinder can be used. Furthermore, the thrust force driving the plunger of the air cylinder is determined only by the cross-sectional area of ​​the cylinder and the pressure of the compressed air used. Therefore, it becomes easy to control the force with which the tip 15 closes the end.

[0184] <Solution tank system (12) equipped with an endline valve according to an embodiment of the present invention> Figure 16 is a diagram showing the configuration of a solution tank system (12) equipped with an endline valve according to an embodiment of the present invention. Figure 16 shows the cross-sectional structure of an anode buffer solution tank and its lid, which is equipped with an endline valve on the bottom side. The left diagram of Figure 16 shows the "valve open" state. The right diagram of Figure 16 shows the "valve closed" state.

[0185] The solution tank system (12) according to this embodiment includes an anode buffer solution tank 3, its lid 11, an end line valve 7, an external flow path 2-1 of the anode buffer solution tank 3, an internal flow path 2-2 of the anode buffer solution tank 3, and so on. Compared to the solution tank system (4) with an end line valve shown in Figure 8, the solution tank system (12) according to this embodiment has some modified components. The explanation of parts that remain unchanged from Figure 8 is partially omitted.

[0186] In the configuration shown in Figure 8, as shown in the right-hand diagram of Figure 8, when the pin 13 is moved downward from the "valve open" state (by pushing the head portion 14), the tip portion 15 is inserted into the end of the internal flow path 2-2 (hole 4), which widens in an inverse tapered shape, and the tip portion 15 closes the end of the internal flow path 2-2 (hole 4), resulting in the "valve closed" state. At this time, the force pushing down the pin 13 is transmitted to the anode buffer solution tank 3, creating a force that separates the anode buffer solution tank 3 from the lid 11.

[0187] Therefore, if the connection between the anode buffer solution tank 3 and the lid 11 is loose, the relative distance between the anode buffer solution tank 3 and the lid 11 will increase, potentially weakening the force with which the tip 15 can seal the end of the internal flow path 2-2 (hole 4), or even making it impossible to seal the end. Furthermore, an increase in the relative distance between the anode buffer solution tank 3 and the lid 11 makes it difficult to achieve a tight seal with the O-ring 16-2. In particular, as in the conventional configuration shown in Figure 3, when the anode buffer solution tank 3 is supported by the sliding friction force of the O-ring 16-1, the relative distance between the anode buffer solution tank 3 and the lid 11 can easily increase when the tip 15 pushes against the bottom surface of the anode buffer solution tank 3.

[0188] Therefore, in Figure 16, in order to strengthen the connection between the anode buffer solution tank 3 and the lid 11 and prevent the relative distance between the anode buffer solution tank 3 and the lid 11 from increasing, the anode buffer solution tank 3 and the lid 11 are fastened and fixed to each other by screws 25. The screws 25 can be driven through the lid 11 from the top surface to the bottom surface and screwed into the screw holes on the upper surface of the side wall of the anode buffer solution tank 3. This makes it possible to stably achieve both the downward movement of the pin 13 to the "valve closed" state and the sealing of the gap between the anode buffer solution tank 3 and the lid 11 by the O-ring 16-2.

[0189] Means other than screws may be used to fix the anode buffer solution tank 3 and the lid 11 to each other. For example, the anode buffer solution tank 3 and the lid 11 may be joined with an interlocking structure so that the relative distance between them does not change. Alternatively, a flange-like portion or the like may be formed on the side wall of the anode buffer solution tank 3, and screw fastening or bolt-nut joining may be performed at that portion.

[0190] The solution tank system (12) according to this embodiment has the same structure as the solution tank system (1), and therefore solves the above-mentioned <first problem>. Furthermore, since the anode buffer solution tank 3 is sealed when the end line valve 7 is in the "valve open" state, the above-mentioned <second problem> to <third problem> can be solved. In addition, since the anode buffer solution tank 3 and the lid 11 are firmly fixed, it is possible to stably achieve the "valve closed" state, prevent a decrease in the airtightness of the anode buffer solution tank 3 when the "valve open" state is achieved, and prevent the anode buffer solution tank 3 from falling out.

[0191] <Solution tank system (13) equipped with an endline valve according to an embodiment of the present invention> Figure 17 is a diagram showing the configuration of a solution tank system (13) equipped with an endline valve according to an embodiment of the present invention. Figure 17 shows the cross-sectional structure of an anode buffer solution tank and its lid, which is equipped with an endline valve on the bottom side. The left diagram of Figure 17 shows the "valve open" state. The right diagram of Figure 17 shows the "valve closed" state.

[0192] The solution tank system (13) according to this embodiment includes an anode buffer solution tank 3, its lid 11, an end line valve 7, an external flow path 2-1 of the anode buffer solution tank 3, an internal flow path 2-2 of the anode buffer solution tank 3, and so on. Compared to the solution tank system (2) with an end line valve shown in Figure 6, the solution tank system (13) according to this embodiment has some modified components. The explanation of parts that remain unchanged from Figure 6 is partially omitted.

[0193] In Figure 17, an auxiliary solution tank 26 is added to the configuration shown in Figure 6. The auxiliary solution tank 26 is a solution tank that contains a solution and either contains air inside, or contains a solution and air such that a liquid level 28 is formed inside. The anode buffer solution tank 3 and the auxiliary solution tank 26 are connected to each other via an external flow path 2-6 (tube 5). One end of the external flow path 2-6 (tube 5) is pressure-resistant connected to the side of the anode buffer solution tank 3 via a ferrule 12.

[0194] A channel 2-5 (hole 4) is formed inside the side wall of the anode buffer solution tank 3. The external channel 2-6 (tube 5) communicates with the inside of the anode buffer solution tank 3 through the internal channel 2-5 (hole 4). The other end of the external channel 2-6 (tube 5) is inserted into the inside of the auxiliary solution tank 26.

[0195] The external channel 2-6 (tube 5) is a channel that contains air or solution. One end of the external channel 2-6 (tube 5) enters the side wall of the anode buffer solution tank 3 from the outside of the anode buffer solution tank 3. The end forming the end face of one end is located inside the anode buffer solution tank 3. The other end of the external channel 2-6 (tube 5) enters the auxiliary solution tank 26 from the outside of the auxiliary solution tank 26. The end forming the end face of the other end is located inside the auxiliary solution tank 26.

[0196] As shown in Figure 17, the height of one end of the external flow path 2-6 (tube 5) is set to be higher than the height of the other end. The height of the ends can be adjusted by the arrangement of the auxiliary solution tank 26 and the external flow path 2-6 (tube 5). In Figure 17, one end of the external flow path 2-6 (tube 5) enters the side wall of the anode buffer solution tank 3 from the side of the anode buffer solution tank 3, but it may also be connected to enter the inside of the lid 11 from above the lid 11.

[0197] A hydrophobic filter 27 is installed at the top of the auxiliary solution tank 26. The hydrophobic filter 27 is a filter that has gas permeability, allowing air to pass through easily, and liquid permeability, making it difficult for liquids such as water to pass through. By installing the hydrophobic filter 27, the inside of the auxiliary solution tank 26 is kept at atmospheric pressure, while preventing the waste liquid 8-3 inside from leaking out of the auxiliary solution tank 26 to the outside. Therefore, the inside of the anode buffer solution tank 3 and the inside of the auxiliary solution tank 26 are kept at atmospheric pressure.

[0198] The liquid level 28 of the waste liquid 8-3 inside the auxiliary solution tank 26 is limited to a lower level compared to the liquid level 9 of the anode buffer solution 8-2 inside the anode buffer solution tank 3. The anode buffer solution 8-2 discharged from the anode buffer solution tank 3 is called waste liquid 8-3.

[0199] If the liquid level 9 of the anode buffer solution is lower than the position where the internal channel 2-5 (hole 4) connects to the inside of the anode buffer solution tank 3, the anode buffer solution 8-2 will not flow through the internal channel 2-5 (hole 4) or the external channel 2-6 (tube 5). Conversely, if the liquid level 9 of the anode buffer solution is higher than the position where the internal channel 2-5 (hole 4) connects to the inside of the anode buffer solution tank 3, the anode buffer solution 8-2 will flow through the internal channel 2-5 (hole 4) or the external channel 2-6 (tube 5) and be discharged into the auxiliary solution tank 26.

[0200] The internal volume of the auxiliary solution tank 26 is made larger than the internal volume of the anode buffer solution tank 3. This configuration prevents the anode buffer solution 8-2 from leaking out of the anode buffer solution tank 3, even if the volume of anode buffer solution 8-2 inside the anode buffer solution tank 3 increases during the analysis or when multiple analyses are repeated. The increased volume inside the anode buffer solution tank 3 can be automatically transferred to the auxiliary solution tank 26.

[0201] According to this embodiment of the solution tank system (13), since it has the same structure as the solution tank system (1), the above-mentioned <first problem> can be solved. Furthermore, because it is equipped with an auxiliary solution tank 26, the height of the liquid level 9 of the anode buffer solution 8-2 can be stably adjusted, and leakage of the anode buffer solution 8-2 can be prevented more reliably.

[0202] <Solution tank system (14) equipped with an endline valve according to an embodiment of the present invention> Figure 18 is a diagram showing the configuration of a solution tank system (14) equipped with an endline valve according to an embodiment of the present invention. Figure 18 shows the cross-sectional structure of an anode buffer solution tank and its lid, which is equipped with an endline valve on the bottom side. The left diagram of Figure 18 shows the "valve open" state. The right diagram of Figure 18 shows the "valve closed" state.

[0203] The solution tank system (14) according to this embodiment includes an anode buffer solution tank 3, its lid 11, an end line valve 7, an external flow path 2-1 of the anode buffer solution tank 3, an internal flow path 2-2 of the anode buffer solution tank 3, and so on. The solution tank system (14) according to this embodiment is an example of combining the above-mentioned multiple components. The solution tank systems (1) to (13) equipped with the above-mentioned end line valve each have different components and achieve the effects of the present invention. The effects of the present invention can be obtained similarly by combining some or all of these components. Explanations of parts that do not change from Figures 4 to 17 are partially omitted.

[0204] In Figure 18, the pin 13 is provided with a shape that has an enlarged diameter portion 22 on the side of the main body that enlarges the outer diameter of the pin 13. An O-ring 16-3 is installed on the upper surface of the enlarged diameter portion 22. Between the lower surface of the head portion 14 and the upper surface of the lid 11, a spring 18 is installed in a compressed state, shortened to its natural length, in a position coaxial with the pin 13.

[0205] Furthermore, the external flow channels 2-3 formed by the tube 5 are pressure-resistantly connected to the upper surface of the lid 11 via the ferrule 12. The external flow channels 2-3 are connected to an air source that supplies pressure-controlled air 19. The anode buffer solution tank 3 and the lid 11 are fastened together by screws 25. In the left diagram of Figure 18, with the end line valve 7 in the "valve open" position, the tip 15 is immersed in the anode buffer solution 8-2, and the tip 15 is close to the upper surface of the bottom of the anode buffer solution tank 3, i.e., the end line valve 7.

[0206] According to this embodiment of the solution tank system (14), since it has the same structure as the solution tank system (1), the above-mentioned <first problem> can be solved. Furthermore, when the end line valve 7 is in the "valve open" state, the O-ring 16-3 is compressed between the upper surface of the enlarged diameter portion 22 and the lower surface of the lid 11, and the anode buffer solution tank 3 is sealed, thus solving the above-mentioned <second problem> to <third problem>. In addition, since the travel distance (stroke) of the pin 13 is reduced, the polymer solution 8-1 inside the capillary is less likely to move due to the difference in water head, and a low-cost solenoid actuator can be used, and the risk of the tip portion 15 coming off the end of the internal flow path 2-2 (hole 4) and failing to "close" when the pin 13 is moved downward from the "valve open" state can be reduced. Furthermore, since air 19 is supplied to the anode buffer solution tank 3 from the outside, the pressure inside the anode buffer solution tank 3 can be controlled, and the pressure difference between both ends of the capillary 101 can be freely controlled. Furthermore, because the elastic force of spring 18 is utilized, the interlocking structure between the pin and actuator is unnecessary, allowing for a lower cost for the solution tank system equipped with an endline valve.

[0207] Figure 19 shows a configuration in which the electrode has been removed from a solution tank system (14) equipped with an endline valve according to an embodiment of the present invention. Figure 19 shows a structure in which the electrode 17, the through hole for connecting the electrode 17 to the lid 11, and the ferrule 12 have been removed from the structure of the solution tank system (14) equipped with an endline valve shown in Figure 18. For solution tanks in which electrophoresis is not performed, a simpler structure may be used, as shown in Figure 19. The same effects as in Figure 18 can be obtained with the structure shown in Figure 19.

[0208] Figure 20 shows a modified configuration of a solution tank system (14) equipped with an endline valve according to an embodiment of the present invention. Figure 20 shows the structure of a modified configuration in which part of the structure of the solution tank system (14) equipped with an endline valve shown in Figure 18 has been changed. The left diagram of Figure 20 shows a structure in which the external flow path 2-1 (tube 5) is connected to the anode buffer solution tank 3 from a horizontal direction. The right diagram of Figure 20 shows a structure in which the external flow path 2-1 (tube 5) is connected to the anode buffer solution tank 3 from an inclined direction.

[0209] In Figure 18, the external flow path 2-1 (tube 5) of the anode buffer solution tank 3 is pressure-resistantly connected to the lower surface of the bottom of the anode buffer solution tank 3 from vertically below via a ferrule 12. However, the method of connecting the external flow path 2-1 (tube 5) is not necessarily limited to this method.

[0210] For example, as shown in the left diagram of Figure 20, the external channel 2-1 (tube 5) may be pressure-resistant connected to the side of the bottom of the anode buffer solution tank 3 from the horizontal direction via the ferrule 12. In this connection method, the internal channel 2-2 (hole 4) at the bottom of the anode buffer solution tank 3 should bend upward midway through its interior and terminate at the point where it reaches the inside of the anode buffer solution tank 3.

[0211] Alternatively, as shown in the right-hand diagram of Figure 20, the external channel 2-1 (tube 5) may be pressure-resistant connected to the bottom surface of the anode buffer solution tank 3 via a ferrule 12, so as to extend diagonally upward from a direction inclined from the vertical. In this connection method, the internal channel 2-2 (hole 4) at the bottom of the anode buffer solution tank 3 may bend upward midway through its interior and terminate at the point where it reaches the interior of the anode buffer solution tank 3.

[0212] However, while the structure shown in Figure 20 is better than the conventional structure shown in Figure 3 compared to the structure shown in Figure 18, the structure of the anode buffer solution tank 3, etc., is somewhat more complex, resulting in slightly higher manufacturing costs. Therefore, the structure shown in Figure 18 is superior to the structure shown in Figure 20.

[0213] Sealing the anode buffer solution tank 3 provides the above-mentioned effects in addition to pressure control. From the viewpoint of reducing leakage of the anode buffer solution 8-2, it is desirable to reduce the inner diameter of the external flow path 2-3 (tube 5) and to close the valve (not shown) provided on the external flow path 2-3 (tube 5). In the conventional structure shown in Figure 3, there is a high possibility that the anode buffer solution 8-2 will leak out of the anode buffer solution tank 3 through the gap between the through hole 20 provided in the lid 11 and the pin 13. Such leakage not only contaminates the surroundings but may also make subsequent analysis impossible. However, sealing the anode buffer solution tank 3 reduces this risk. Furthermore, sealing the anode buffer solution tank 3 can reduce the risk of discharge occurring from the anode buffer solution tank 3 to the outside when a high voltage is applied to the electrode 17. However, since the upper end of the electrode 17 is exposed, separate measures to prevent discharge are necessary for this part.

[0214] In the conventional configuration shown in Figure 3, the solenoid actuator needs to move the pin 13 in both upward and downward directions, requiring a structure that is fixed to the solenoid actuator or a meshing structure between the solenoid actuator and the pin 13. In contrast, in the configurations shown in Figures 18 to 20, the solenoid actuator only needs to move the pin 13 downward, so a structure that is fixed to the solenoid actuator or a meshing structure between the solenoid actuator and the pin 13 is unnecessary.

[0215] Forming these structures requires mechanisms and effort. Eliminating these requirements simplifies the device, reducing manufacturing costs and analytical effort. This effect is particularly significant when replacing the solution tank system while maintaining and reusing actuators, and becomes even greater when the replacement frequency is high.

[0216] Instead of a solenoid actuator, any other actuator, such as a stepping motor, may be used to drive pin 13. For example, using an air cylinder can reduce the cost of the device. As shown in Figures 18 to 20, the vertical travel distance (stroke) of pin 13 is relatively short, so a small air cylinder can be used. Furthermore, the thrust of the plunger of the air cylinder is determined only by the cross-sectional area of ​​the cylinder and the pressure of the compressed air used. Therefore, it becomes possible to easily control the force with which the tip 15 closes the end.

[0217] <Configuration and Analysis Process of a Capillary Electrophoresis Apparatus According to an Embodiment of the Present Invention> Figure 21 is a diagram showing the configuration of a capillary electrophoresis apparatus according to an embodiment of the present invention. As shown in Figure 21, the capillary electrophoresis apparatus according to this embodiment comprises a capillary 101, an anode electrode 106, an anode block 118, a pressure-resistant syringe 119, an anode buffer solution tank 123, a lid 124, a cathode electrode 105, a cathode buffer solution tank 109, a sample solution tank 111, a cathode stage 114, a laser light source 135, and the like.

[0218] The capillary electrophoresis apparatus according to this embodiment may include at least one of the solution tank systems shown in Figures 4 to 20, as the anode buffer solution tank 123. Preferably, the solution tank system includes a configuration in which the anode buffer solution tank 3 is airtightly sealed.

[0219] In the conventional capillary electrophoresis apparatus shown in Figure 2, atmospheric pressure capillary electrophoresis is performed with both ends of the capillary under atmospheric pressure. In contrast, the capillary electrophoresis apparatus according to this embodiment can switch between atmospheric pressure capillary electrophoresis, which is performed with both ends of the capillary under atmospheric pressure, and double-ended pressurized electrophoresis, which is performed with both ends of the capillary under pressure. In double-ended pressurized electrophoresis, electrophoresis is performed while applying a constant pressure, such as 1 atmosphere, to both ends of the capillary.

[0220] Capillary electrophoresis with pressure at both ends can stabilize electrophoretic analysis by suppressing the generation of air bubbles inside the capillary. Therefore, by modifying the conventional capillary electrophoresis apparatus shown in Figure 2, a capillary electrophoresis apparatus capable of capillary electrophoresis with pressure at both ends, as shown in Figure 21, will be constructed. In the following explanation, some parts that are the same as in Figure 2 will be omitted.

[0221] In the capillary electrophoresis apparatus according to this embodiment, an O-ring 113 is installed on the upper edge of the wall of each of the cathode buffer solution tank 109 and the sample solution tank 111. A fixing block 115 is fixed to the main body of the capillary electrophoresis apparatus. The fixing block 115 is a member having a horizontal lower surface and a flow channel formed inside.

[0222] The cathode end 102, along with the cathode electrode 105, is inserted into the cathode buffer solution tank 109 and immersed in the cathode buffer solution 110 by moving the cathode stage 114 using an automatic XYZ stage. The upward movement of the cathode stage 114 can press the O-ring 113 against the underside of the fixed block 115 and compress it. The compression of the O-ring 113 seals the gap between the fixed block 115 and the cathode buffer solution tank 109. Alternatively, the upward movement of the cathode stage 114 can be stopped before the O-ring 113 is compressed, so that the gap between the fixed block 115 and the cathode buffer solution tank 109 is not sealed.

[0223] The cathode buffer solution tank 109 is connected to an air source 130 that supplies pressure-controlled air via an air tube 129 to which a valve 133 is connected, or via a flow path 116 formed inside the fixed block 115. Alternatively, the cathode buffer solution tank 109 is connected to the outside under atmospheric pressure via an air tube 129 to which a valve 134 is connected, or via a flow path 116 formed inside the fixed block 115.

[0224] In Figure 21, with the gap between the fixed block 115 and the cathode buffer solution tank 109 sealed by the compression of the O-ring 113, if valve 133 is "closed" and valve 134 is "open", the air inside the cathode buffer solution tank 109 will be at atmospheric pressure. Conversely, if valve 133 is "open" and valve 134 is "closed", the air inside the cathode buffer solution tank 109 will be at the pressure of the air supplied by the air source 130.

[0225] The anode buffer solution tank 123 is covered with a lid 124. The anode electrode 106 is inserted into the anode buffer solution tank 123 by passing through the lid 124 from top to bottom. The tip of the anode electrode 106 is immersed in the anode buffer solution 125 contained inside the anode buffer solution tank 123.

[0226] A pressure-resistant syringe 119 and a tube forming a flow path 122 are pressure-resistant connected to the internal flow path 137 of the anode block 118. The end of the external flow path 122 formed by the tube, opposite to the anode block 118, is connected to the bottom of the anode buffer solution tank 123. An end-line valve 128 is installed at the boundary between the external flow path 122 connecting the anode block 118 and the anode buffer solution tank 123 and the inside of the anode buffer solution tank 123.

[0227] The endline valve 128 includes a pin 127 that forms the valve body. The pin 127 is provided to be movable up and down. When the pin 127 moves upward, the endline valve 128 is in the "valve open" state. Conversely, when the pin 127 moves downward, the endline valve 128 is in the "valve closed" state.

[0228] When the endline valve 128 is in the "open" position, the anode buffer solution tank 123 is sealed. On the other hand, when the endline valve 128 is in the "closed" position, the anode buffer solution tank 123 is open to the atmosphere.

[0229] In Figure 21, when the endline valve 128 is in the "open" position, valve 131 is in the "closed" position, and valve 132 is in the "open" position, the air inside the cathode buffer solution tank 109 becomes atmospheric pressure. Conversely, when valve 131 is in the "open" position and valve 132 is in the "closed" position, the air inside the anode buffer solution tank 123 becomes the pressure of the air supplied by the air source 130, with the pressure controlled.

[0230] Figures 22, 23, 24, 25, 26, and 27 illustrate the capillary electrophoresis analysis process using a capillary electrophoresis apparatus according to an embodiment of the present invention. Figure 22 shows the configuration during [1] polymer solution filling. Figure 23 shows the configuration during [2] preliminary electrophoresis. Figure 24 shows the configuration during [3a] electric field injection of the sample. Figure 25 shows the configuration during [3b] pressure injection of the sample. Figure 26 shows the configuration during [4a] atmospheric pressure electrophoresis. Figure 27 shows the configuration during [4b] double-ended pressurized electrophoresis. Note that Figure 21 corresponds to the initial configuration.

[0231] [1] Filling the polymer solution As shown in Figure 22, valve 131 is "closed", valve 132 is "open", valve 133 is "closed", and valve 134 is "open", and both the flow path 116 formed inside the fixed block 115 and the external flow path 126 connected to the lid 124 are opened to the atmosphere. In this state, the cathode stage 114 is moved by the automatic XYZ stage and the cathode end 102 is inserted into the waste liquid tank (not shown). Next, the pin 127 is moved downward to close the end line valve 128. In this state, the plunger 120 of the pressure-resistant syringe 119 is mechanically pushed in by the actuator and high pressure is applied to the polymer solution 140 inside the anode block 118.

[0232] The high-pressure polymer solution 140 inside the anode block 118, the high-pressure polymer solution 140 inside the channel 122 connecting the anode block 118 and the anode buffer solution tank 123, and the high-pressure polymer solution 140 inside the pressure-resistant syringe 119 form a continuous liquid system. This liquid system fills the sealed space, and virtually no air is contained within these sealed spaces. Furthermore, the anode end 103 becomes immersed in this liquid system.

[0233] Therefore, the high pressure applied by the plunger 120 is transmitted throughout the entire liquid system, including the anode end 103. Meanwhile, the cathode end 102 is immersed in the cathode buffer solution 110 under atmospheric pressure. As a result, a high pressure difference is formed between the anode end 103 and the cathode end 102. This pressure difference causes the polymer solution 140 to fill the inside of the capillary 101 from the anode end 103 to the cathode end 102.

[0234] The pressure applied to this liquid system can be adjusted by controlling the force of the actuator that pushes the plunger 120. For example, a high pressure of 35 atmospheres is applied to the liquid system to fill the capillary 101 with polymer solution 140 at high pressure. After filling with polymer solution 140, the pushing of the plunger 120 is stopped, separating the plunger 120 from the mechanism that mechanically pushes the plunger 120, so that no external pressure is applied to the liquid system.

[0235] However, in reality, some pressure may remain due to the frictional force of the plunger 120, and the pressure applied to the liquid system may not be zero. Therefore, the pin 127 is moved upward, and the end line valve 128 is opened, opening the anode end 103 and the liquid system to the atmosphere. Since the anode buffer solution tank 123 is open to the atmosphere, when the end line valve 128 is opened, the anode end 103 becomes at the same atmospheric pressure as the outside.

[0236] [2] As shown in the preliminary electrophoresis diagram 23, after filling the capillary 101 with polymer solution 140, the cathode stage 114 is moved by the automatic XYZ stage to insert the cathode end 102 into the cathode buffer solution tank 109 and immerse it in the cathode buffer solution 110. In this state, the switch 139 is turned ON and a predetermined voltage is applied between the anode end 103 and the cathode end 102 for a predetermined time to perform preliminary electrophoresis.

[0237] [3a] Sample injection (electric field injection) As shown in Figure 24, when an electric field is injected into the capillary 101, the cathode stage 114 is moved by the automatic XYZ stage so that the cathode end 102 is inserted into the sample solution tank 111 and immersed in the sample solution 112. In this state, the switch 139 is turned ON and a predetermined voltage is applied between the anode end 103 and the cathode end 102 of the capillary 101 for a predetermined time to perform electric field injection of the sample. By electric field injection, the sample components contained in the sample solution 112 are injected into the inside of the capillary 101 from the cathode end 102.

[0238] [3b] Sample injection (pressure injection) As shown in Figure 25, when injecting the sample into the capillary 101 under pressure, the cathode stage 114 is moved by the automatic XYZ stage so that the cathode end 102 is inserted into the sample solution tank 111 and immersed in the sample solution 112. Also, the O-ring 113 is pressed against the horizontal lower surface of the fixed block 115 and compressed to seal the gap between the fixed block 115 and the sample solution tank 111. The inside of the anode buffer solution tank 123 is kept at atmospheric pressure. In this state, for a predetermined time, valve 133 is set to "open" and valve 134 is set to "closed" to supply high-pressure air 141 at a pressure higher than the predetermined atmospheric pressure into the sample solution tank 111 by the air source 130 and perform pressure injection of the sample. Due to the pressure injection, the sample solution 112 is injected into the inside of the capillary 101 from the cathode end 102.

[0239] [4a] Electrophoresis (Atmospheric Pressure Electrophoresis) As shown in Figure 26, when performing atmospheric pressure electrophoresis of a sample, the cathode stage 114 is moved by the automatic XYZ stage so that the cathode end 102 is inserted into the cathode buffer solution tank 109 and immersed in the cathode buffer solution 110. In this state, the switch 139 is turned ON and a predetermined voltage is applied between the anode end 103 and the cathode end 102 so that electrophoresis (atmospheric pressure electrophoresis) is performed with both ends of the capillary 101 under atmospheric pressure.

[0240] [4b] Electrophoresis (Both ends pressurized electrophoresis) As shown in Figure 27, when performing both ends pressurized electrophoresis of a sample, the cathode stage 114 is moved by the automatic XYZ stage to insert the cathode end 102 into the cathode buffer solution tank 109 and immerse it in the cathode buffer solution 110. In addition, the O-ring 113 is pressed against the horizontal lower surface of the fixed block 115 and compressed to seal the gap between the fixed block 115 and the cathode buffer solution tank 109. Furthermore, the end line valve 128 is set to the "valve open" position to seal the inside of the anode buffer solution tank 123. In this state, valve 131 is set to "open," valve 132 to "closed," valve 133 to "open," and valve 134 to "closed," and high-pressure air 141, which is common and at a pressure higher than a predetermined atmospheric pressure, is supplied from the air source 130 to the inside of the anode buffer solution tank 123 and the cathode buffer solution tank 109, thereby applying a common pressure. Also, switch 139 is turned ON to apply a predetermined voltage between the anode end 103 and the cathode end 102. Through these operations, electrophoresis (double-ended pressure electrophoresis) is performed with pressure applied to both ends of the capillary 101.

[0241] When repeating the analysis of multiple capillary electrophoresis samples, repeat steps [1] to [4] above. However, for sample injection, perform either [3a] or [3b], and for electrophoresis, perform either [4a] or [4b].

[0242] With the capillary electrophoresis apparatus according to this embodiment, atmospheric pressure capillary electrophoresis and double-ended pressure electrophoresis can be switched between, allowing for selective execution of either atmospheric pressure capillary electrophoresis or double-ended pressure electrophoresis depending on the required analytical conditions and required accuracy.

[0243] <Configuration of an Autosampler-less Capillary Electrophoresis Apparatus> In the conventional capillary electrophoresis apparatus shown in Figure 2, with the cathode end 102 of the capillary 101 fixed, the automatic XYZ stage (or automatic XZ stage) of the cathode stage 114 is moved to immerse the cathode end 102 in the cathode buffer solution 110, the sample solution 112, or any other solution. This type of mechanism is called an autosampler.

[0244] While autosamplers are convenient, they are costly because they require an automated stage using multiple stepping motors. Furthermore, they require a large amount of space when installed in a capillary electrophoresis system. To reduce the cost and size of capillary electrophoresis systems, it is effective to construct an autosampler-less capillary electrophoresis system that does not incorporate an autosampler.

[0245] In the conventional capillary electrophoresis apparatus shown in Figure 2, only the anode end 103 of the capillary 101 is fixed to the anode block 118, while the cathode end 102 is fixed in the air. In contrast, in the autosampler-less capillary electrophoresis apparatus according to this embodiment, the anode end is fixed to the anode block, and the cathode end is fixed to the cathode block. By fixing these components, an autosampler-less capillary electrophoresis apparatus can be constructed.

[0246] Figures 28A, 28B, and 28C are cross-sectional views showing the configuration of an autosampler-less capillary electrophoresis apparatus according to an embodiment of the present invention. In the following figures, the depiction of connecting jigs such as ferrules for fixing or connecting each component to a block or flow path is omitted.

[0247] Figure 28A shows the configuration of an autosampler-less capillary electrophoresis apparatus (1). The capillary 201 is mounted with its cathode end 202 on the side of the cathode block 206 (left side) and its anode end 203 on the side of the anode block 207 (right side). The cathode end 202 is connected to a channel 216 inside the cathode block 206. The anode end 203 is connected to a channel 223 inside the anode block 207. The cathode block 206 and anode block 207 can be made of transparent acrylic resin to allow observation of their interiors.

[0248] The internal channel 216 of the cathode block 206 extends from the inlet 217 and splits into two at the branching point 218. One of the two branches is connected to the cathode buffer solution tank system 212. The cathode buffer solution tank system 212 includes a cathode buffer solution tank, a first cathode electrode 204-1, an end-line valve 219, etc. The first cathode electrode 204-1 is immersed in the cathode buffer solution 221 inside the cathode buffer solution tank. The first cathode electrode 204-1 is an electrode for electrophoresis. The other branch is connected to the waste liquid tank system 213. The waste liquid tank system 213 includes a waste liquid tank, an end-line valve 220, etc.

[0249] Various gases and liquids, such as air, buffer solution, sample solution, and water, can be introduced into the channel 216 inside the cathode block 206 from the inlet 217. The cathode end 202 of the capillary 201 is positioned in the channel 216 between the inlet 217 and the branching point 218. A second cathode electrode 204-2 is positioned in the channel 216 between the position where the cathode end 202 is located and the branching point 218. The second cathode electrode 204-2 is an electrode for electric field injection.

[0250] The channel 216 inside the cathode block 206 is filled with cathode buffer solution 221 during electrophoresis, etc. The inside of the cathode buffer solution tank is filled with cathode buffer solution 221 and air during electrophoresis, etc. The inside of the waste liquid tank is filled with waste liquid 215 containing cathode buffer solution 221 and air after the completion of electrophoresis, etc.

[0251] The cathode buffer solution tank system 212 can be configured in any of the configurations shown in Figures 4 to 20, but the following description will use the configuration shown in Figure 18. However, Figure 28A shows a simplified version of the configuration in Figure 18. Without using the external flow path 2-1 (tube 5) and ferrule 12 in Figure 18, the internal flow path 2-2 (hole 4) in Figure 18 and the internal flow path 216 of the cathode block 206 in Figure 28A are directly connected, and an end line valve 219 is provided at the boundary between them.

[0252] In Figure 28A, the endline valve 219 is in the "valve open" position. Atmospheric air is supplied to the inside of the cathode buffer solution tank from a channel (not shown) corresponding to the external channel 2-3 (tube 5) connected to the lid 11 in Figure 18, so that the inside is maintained at atmospheric pressure.

[0253] The waste liquid tank system 213 can be installed in any of the configurations shown in Figures 4 to 20, but the following description will use the configuration shown in Figure 19. However, Figure 28A shows a simplified version of the configuration in Figure 19. Without using the external flow path 2-1 (tube 5) and ferrule 12 in Figure 19, the internal flow path 2-2 (hole 4) in Figure 19 and the internal flow path 216 of the cathode block 206 in Figure 28A are directly connected, and an end line valve 220 is provided at the boundary between them.

[0254] In Figure 28A, the endline valve 220 is in the "valve closed" state. Atmospheric air is supplied to the inside of the waste liquid tank from a channel (not shown) corresponding to the external channel 2-3 (tube 5) connected to the lid 11 in Figure 19, so that the inside of the solution tank is maintained at atmospheric pressure.

[0255] A cylinder 224, which constitutes a plunger pump, is formed at one end of the flow path 223 inside the anode block 207. The outer end of the cylinder 224 is sealed by a seal portion 227 that functions as a piston. The movement of the seal portion 227 relative to the cylinder 224 is driven by a plunger 228. The anode end 203 of the capillary 201 is located in the middle of the flow path 223 inside the anode block 207.

[0256] During electrophoresis, polymer solution 226 is filled into the internal channels 223 of cylinder 224 and anode block 207. An anode buffer solution tank system 214 is connected to the other end of the internal channel 223 of anode block 207. The anode buffer solution tank system 214 includes an anode buffer solution tank, an anode electrode 205, an end-line valve 225, etc. During electrophoresis, anode buffer solution 222 and air are filled into the anode buffer solution tank. The anode electrode 205 is immersed in the anode buffer solution 222 inside the anode buffer solution tank.

[0257] The anode buffer solution tank system 214 can be configured in any of the configurations shown in Figures 4 to 20, but the following description will use the configuration shown in Figure 18. However, Figure 28A shows a simplified version of the configuration in Figure 18. Without using the external flow path 2-1 (tube 5) and ferrule 12 in Figure 18, the internal flow path 2-2 (hole 4) in Figure 18 and the internal flow path 223 of the anode block 207 in Figure 28A are directly connected, and an end line valve 225 is provided at the boundary between them.

[0258] In Figure 28A, the endline valve 225 is in the "valve open" position. Atmospheric air is supplied to the anode buffer solution tank from a channel (not shown) corresponding to the external channel 2-3 (tube 5) connected to the lid 11 in Figure 18, so that the inside is maintained at atmospheric pressure.

[0259] With the endline valve 225 in the "valve closed" position, the plunger 228 pushes the seal portion 227 into the cylinder 224, applying high pressure to the polymer solution 226 inside the cylinder 224 and the polymer solution 226 inside the flow path 223 inside the anode block 207. This pressure allows the polymer solution 226 to be filled into the capillary 201.

[0260] The cathode buffer solution tank, waste liquid tank, and anode buffer solution tank can all be made of transparent acrylic resin so that their internal components can be observed.

[0261] The first cathode electrode 204-1 and the second cathode electrode 204-2 and the anode electrode 205 are connected to a DC high-voltage power supply 211 via a wire 208. A high voltage is applied between the two electrodes by the DC high-voltage power supply 211 during sample injection and electrophoresis. The first cathode electrode 204-1 and the second cathode electrode 204-2 are grounded, and the anode electrode 205 is subjected to a positive high voltage.

[0262] Switch 209, connected in series with the first cathode electrode 204-1, and switch 210, connected in series with the second cathode electrode 204-2, respectively, switch between connecting and disconnecting the first cathode electrode 204-1 to the DC high voltage power supply 211, or connecting and disconnecting the second cathode electrode 204-2 to the DC high voltage power supply 211.

[0263] Figure 28B shows the configuration of the autosampler-less capillary electrophoresis apparatus (2). Compared to the autosampler-less capillary electrophoresis apparatus (1) in Figure 28A, Figure 28B shows changes in the configuration of the flow path 216 inside the cathode block 206 and the flow paths connected to the cathode buffer solution tank system 212 and the waste liquid tank system 213. However, there is no change in the fact that the flow path 216 inside the cathode block 206 extends from the inlet 217 and branches into two at the branching point 218.

[0264] One end of the two-way connection is connected to the cathode buffer solution tank system 212 via an external channel 230 formed by a tube. The other end of the two-way connection is connected to the waste liquid tank system 213 via an external channel 231 formed by a tube. In addition, the internal channel 223 of the anode block 207 is connected to the anode buffer solution tank system 214 via an external channel 229 formed by a tube.

[0265] According to the configuration in Figure 28B, since each solution tank system is connected by tubing, each solution tank system can be positioned more freely compared to the configuration in Figure 28A. This increases the design flexibility of the autosampler-less capillary electrophoresis apparatus. For example, it becomes easier to adjust the liquid level inside each solution tank by adjusting the head difference, etc.

[0266] In Figure 28B, it is also possible to use the configuration shown in Figure 3 instead of the configurations shown in Figure 18, etc., for the cathode buffer solution tank system 212, the waste liquid tank system 213, and the anode buffer solution tank system 214. In other words, it is also possible to construct an autosampler-less capillary electrophoresis apparatus using a conventional solution tank system. However, in that case, it becomes difficult to reduce the cost and miniaturize the apparatus.

[0267] The autosampler-less capillary electrophoresis apparatus shown in Figures 28A to 28B differs in some structural aspects, resulting in different design flexibility for each component. However, the performance of capillary electrophoresis using each apparatus is essentially the same. Compared to the conventional capillary electrophoresis apparatus shown in Figures 28A to 28B, the autosampler-less capillary electrophoresis apparatus shown in Figure 2 offers advantages in terms of ensuring airtightness of the solution tank and flow path, and in the arrangement of capillaries and electrodes.

[0268] Figure 28C shows the configuration of the autosampler-less capillary electrophoresis apparatus (3). In Figure 28C, some of the configuration of the autosampler-less capillary electrophoresis apparatus (1) in Figure 28A has been changed. Some explanations of parts that are the same as in Figure 28A have been omitted. The configuration of the channel 216 inside the cathode block 206 has been changed, but the fact that the channel 216 extends from the inlet 217 and splits into two at the branching point 218 remains unchanged.

[0269] In Figure 28A, the capillary 201 is connected horizontally to the cathode block 206 and the anode block 207. In contrast, in Figure 28C, the capillary 201 is connected vertically to the cathode block 206 and the anode block 207. Compared to the configuration in Figure 28A, the configuration in Figure 28C allows for a more flexible layout of the capillary, resulting in increased design flexibility.

[0270] Figure 29A shows the structure of the cathode block 206 of the autosampler-less capillary electrophoresis apparatus (3) shown in Figure 28C, and is a cross-sectional view of the cathode block 206 of Figure 28C, viewed from above, with the cross section passing through the inlet 217 and parallel to the horizontal direction.

[0271] The flow path 216 inside the cathode block 206 extends from the inlet 217, passes through the location where the end face of the cathode end 202 of the capillary 201 is located, the location where the end face of the second cathode electrode 204-2 is located, and the location where the cathode buffer solution tank system 212 is connected, and reaches the waste liquid tank system 213.

[0272] In Figure 29A, as in Figure 28C, the end line valve 219 is in the "open" state and the end line valve 220 is in the "closed" state. In Figure 29A, the "open" state is indicated by ○ and the "closed" state by ●. This notation will be used in the same way in subsequent figures.

[0273] <Analysis Process using Autosampler-less Capillary Electrophoresis Apparatus (1)> Figures 30A to 30I illustrate the analysis process using the autosampler-less capillary electrophoresis apparatus (1). Figures 30A to 30I show the analysis process by capillary electrophoresis using the autosampler-less capillary electrophoresis apparatus (1) shown in Figure 28A in chronological order.

[0274] Figure 30A shows the initial state. The flow path 216 inside the cathode block 206 is filled with cathode buffer solution 221. The cylinder 224 and the flow path 223 inside the anode block 207 are filled with polymer solution 226. The end line valve 219 of the cathode buffer solution tank system 212 is "valve open", the end line valve 220 of the waste liquid tank system 213 is "valve closed", and the end line valve 225 of the anode buffer solution tank system 214 is "valve open".

[0275] Figure 30B shows the process of filling the capillary with polymer solution. The end line valve 219 of the cathode buffer solution tank system 212 is "closed", the end line valve 220 of the waste liquid tank system 213 is "open", and the end line valve 225 of the anode buffer solution tank system 214 is "closed". In this state, the plunger 228 is pushed into the inside of the cylinder 224 with a constant load by a single-axis stage (not shown) driven by a stepping motor. This load is applied to the polymer solution 226 inside the cylinder 224 and the polymer solution 226 inside the flow path 223 inside the anode block 207 via the seal portion 227. These polymer solutions 226 become, for example, a high-pressure polymer solution 301 at 35 atmospheres. The end line valve 225 is provided with high pressure resistance to prevent leakage of the high-pressure polymer solution 301. Meanwhile, the cathode buffer solution 221 inside the flow path 216 inside the cathode block 206 is kept at atmospheric pressure. Due to this pressure difference between the two ends, the polymer solution 226 fills the inside of the capillary 201 from the anode end 203 towards the cathode end 202.

[0276] Figure 30C shows the process of performing preliminary electrophoresis. The end line valve 219 of the cathode buffer solution tank system 212 is set to "open", the end line valve 220 of the waste liquid tank system 213 is set to "closed", and the end line valve 225 of the anode buffer solution tank system 214 is set to "open". With this in place, switch 209 is turned ON, the first cathode electrode 204-1 and the anode electrode 205 are connected to the DC high voltage power supply 211, and a high voltage is applied between the two electrodes to perform preliminary electrophoresis.

[0277] Figures 30D to 30F show the process of performing electric field implantation of the sample. As shown in Figure 30D, the end line valve 219 of the cathode buffer solution tank system 212 is "closed", the end line valve 220 of the waste liquid tank system 213 is "open", and the end line valve 225 of the anode buffer solution tank system 214 is "open". In this state, air 302 is introduced into the flow path 216 inside the cathode block 206 from the inlet 217, the cathode buffer solution 221 inside the flow path 216 is discharged into the waste liquid tank, and the inside of the flow path 216 is replaced with air 302. However, since the end line valve 219 is "closed", the flow path 216 between the branching point 218 and the cathode buffer solution tank system 212 is maintained in a state where it is filled with cathode buffer solution 221.

[0278] Next, as shown in Figure 30E, the sample solution 303 is introduced into the flow path 216 inside the cathode block 206 from the inlet 217, so that the sample solution 303 comes into contact with the cathode end 202 and the second cathode electrode 204-2, and the downstream end of the sample solution 303 is located between the second cathode electrode 204-2 and the branching point 218. At this time, some of the air 302 inside the flow path 216 is discharged into the waste liquid tank. Since the end line valve 219 is "valve closed", the flow path 216 between the branching point 218 and the cathode buffer solution tank system 212 is maintained filled with the cathode buffer solution 221.

[0279] Next, as shown in Figure 30F, the end line valve 219 of the cathode buffer solution tank system 212 is set to "closed", the end line valve 220 of the waste liquid tank system 213 is set to "closed", and the end line valve 225 of the anode buffer solution tank system 214 is set to "open". With this setting, switch 210 is turned ON, the second cathode electrode 204-2 and the anode electrode 205 are connected to the DC high voltage power supply 211, and a high voltage is applied between the two electrodes to perform electric field injection of the sample.

[0280] Figures 30G to 30I show the process of performing electrophoresis on the sample. As shown in Figure 30G, the end line valve 219 of the cathode buffer solution tank system 212 is "closed", the end line valve 220 of the waste liquid tank system 213 is "open", and the end line valve 225 of the anode buffer solution tank system 214 is "open". In this state, air 302 is introduced into the flow path 216 inside the cathode block 206 from the inlet 217, and the air 302 and sample solution 303 inside the flow path 216 are discharged into the waste liquid tank, replacing the inside of the flow path 216 with air 302. However, since the end line valve 219 of the cathode buffer solution tank system 212 is "closed", the flow path 216 between the branching point 218 and the cathode buffer solution tank system 212 is maintained in a state where it is filled with cathode buffer solution 221.

[0281] Next, as shown in Figure 30H, cathode buffer solution 221 is introduced into the flow path 216 inside the cathode block 206 from the inlet 217, the air 302 inside the flow path 216 is discharged into the waste liquid tank, and the inside of the flow path 216 is replaced with cathode buffer solution 221. The cathode buffer solution 221 introduced from the inlet 217 is merged with the cathode buffer solution 221 remaining in the flow path 216 between the branching point 218 and the cathode buffer solution tank system 212 without introducing air bubbles.

[0282] Next, as shown in Figure 30I, the end line valve 219 of the cathode buffer solution tank system 212 is set to "open," the end line valve 220 of the waste liquid tank system 213 is set to "closed," and the end line valve 225 of the anode buffer solution tank system 214 is set to "open." With this setup, switch 209 is turned ON, the first cathode electrode 204-1 and the anode electrode 205 are connected to the DC high-voltage power supply 211, and a high voltage is applied between the two electrodes to perform electrophoresis of the sample.

[0283] Electrophoretic analysis using such an autosampler-less capillary electrophoresis apparatus can achieve electrophoretic performance equivalent to that of conventional capillary electrophoresis apparatuses. At the same time, it eliminates the need for the autosampler that is standard in conventional capillary electrophoresis apparatuses, thus enabling cost reduction and miniaturization of the apparatus. The endline valve functions effectively, allowing the cathode buffer solution 221 introduced into the cathode block 206 from the inlet 217 and the cathode buffer solution 221 remaining inside to merge into a single continuous solution without the introduction of air bubbles, thus enabling stable analysis.

[0284] <Analysis process using an autosampler-less capillary electrophoresis apparatus (2)> Figures 31A to 31I illustrate the analysis process using an autosampler-less capillary electrophoresis apparatus (3). Figures 31A to 31I show the analysis process by capillary electrophoresis using the autosampler-less capillary electrophoresis apparatus (3) shown in Figures 28C and 29A in chronological order.

[0285] Figures 31A to 31I show a cross-sectional view of the cathode block 206 from the side on the left, similar to Figure 28C, and a cross-sectional view of the cathode block 206 from above on the right, similar to Figure 29A. The left and right figures show the cathode block 206 in the same state. The anode block 207 is not shown in Figures 31A to 31I.

[0286] In Figures 31A to 31I, as in Figures 30A to 30I, the inside of the cathode buffer solution tank, the waste liquid tank, and the anode buffer solution tank are kept at atmospheric pressure.

[0287] Figure 31A shows the initial state. The flow path 216 inside the cathode block 206 is filled with cathode buffer solution 221. The cylinder 224 and the flow path 223 inside the anode block 207 are filled with polymer solution 226. The end line valve 219 of the cathode buffer solution tank system 212 is "valve open", the end line valve 220 of the waste liquid tank system 213 is "valve closed", and the end line valve 225 of the anode buffer solution tank system 214 is "valve open".

[0288] Figure 31B shows the process of filling the capillary with polymer solution. The end line valve 219 of the cathode buffer solution tank system 212 is "closed", the end line valve 220 of the waste liquid tank system 213 is "open", and the end line valve 225 of the anode buffer solution tank system 214 is "closed". In this state, the plunger 228 is pushed into the inside of the cylinder 224 with a constant load by a single-axis stage driven by a stepping motor. This load is applied to the polymer solution 226 inside the cylinder 224 and the polymer solution 226 inside the flow path 223 via the seal portion 227. The polymer solution 226 becomes, for example, a high-pressure polymer solution 301 at 35 atmospheres. The end line valve 225 is provided with high pressure resistance to prevent leakage of the high-pressure polymer solution 301. On the other hand, the cathode buffer solution 221 inside the flow path 216 inside the cathode block 206 is at atmospheric pressure. Due to this pressure difference between the two ends, the polymer solution 226 fills the inside of the capillary 201 from the anode end 203 toward the cathode end 202.

[0289] Figure 31C shows the process of performing preliminary electrophoresis. The end line valve 219 of the cathode buffer solution tank system 212 is set to "open", the end line valve 220 of the waste liquid tank system 213 is set to "closed", and the end line valve 225 of the anode buffer solution tank system 214 is set to "open". With this in place, switch 209 is turned ON, the first cathode electrode 204-1 and the anode electrode 205 are connected to the DC high voltage power supply 211, and a high voltage is applied between the two electrodes to perform preliminary electrophoresis.

[0290] Figures 31D to 31F show the process of performing electric field implantation of the sample. As shown in Figure 31D, the end line valve 219 of the cathode buffer solution tank system 212 is "closed", the end line valve 220 of the waste liquid tank system 213 is "open", and the end line valve 225 of the anode buffer solution tank system 214 is "open". In this state, air 302 is introduced into the flow path 216 inside the cathode block 206 from the inlet 217, the cathode buffer solution 221 inside the flow path 216 is discharged into the waste liquid tank, and the inside of the flow path 216 is replaced with air 302. However, since the end line valve 219 is "closed", the flow path 216 between the branching point 218 and the cathode buffer solution tank system 212 is maintained in a state where it is filled with cathode buffer solution 221.

[0291] Next, as shown in Figure 31E, the sample solution 303 is introduced into the flow path 216 inside the cathode block 206 from the inlet 217, so that the sample solution 303 comes into contact with the cathode end 202 and the second cathode electrode 204-2, and the downstream end of the sample solution 303 is located between the second cathode electrode 204-2 and the branching point 218. At this time, some of the air 302 inside the flow path 216 is discharged into the waste liquid tank. Since the end line valve 219 is "valve closed", the flow path 216 between the branching point 218 and the cathode buffer solution tank system 212 is maintained to be filled with cathode buffer solution 221.

[0292] Next, as shown in Figure 31F, the end line valve 219 of the cathode buffer solution tank system 212 is set to "closed", the end line valve 220 of the waste liquid tank system 213 is set to "closed", and the end line valve 225 of the anode buffer solution tank system 214 is set to "open". With this setting, switch 210 is turned ON, the second cathode electrode 204-2 and the anode electrode 205 are connected to the DC high voltage power supply 211, and a high voltage is applied between the two electrodes to perform electric field injection of the sample.

[0293] Figures 31G to 31I show the process of performing electrophoresis on a sample. As shown in Figure 31G, the end line valve 219 of the cathode buffer solution tank system 212 is "closed", the end line valve 220 of the waste liquid tank system 213 is "open", and the end line valve 225 of the anode buffer solution tank system 214 is "open". In this state, air 302 is introduced into the flow path 216 inside the cathode block 206 from the inlet 217, and the air 302 and sample solution 303 inside the flow path 216 are discharged into the waste liquid tank, replacing the inside of the flow path 216 with air 302. However, since the end line valve 219 is "closed", the flow path 216 between the branching point 218 and the cathode buffer solution tank system 212 is maintained in a state where it is filled with cathode buffer solution 221.

[0294] Next, as shown in Figure 31H, cathode buffer solution 221 is introduced into the flow path 216 inside the cathode block 206 from the inlet 217, the air 302 inside the flow path 216 is discharged into the waste liquid tank, and the inside of the flow path 216 is replaced with cathode buffer solution 221. The cathode buffer solution 221 introduced from the inlet 217 is merged with the cathode buffer solution 221 remaining in the flow path 216 between the branching point 218 and the cathode buffer solution tank system 212 without introducing air bubbles.

[0295] Next, as shown in Figure 31I, the end line valve 219 of the cathode buffer solution tank system 212 is set to "open," the end line valve 220 of the waste liquid tank system 213 is set to "closed," and the end line valve 225 of the anode buffer solution tank system 214 is set to "open." In this state, switch 209 is turned ON, the first cathode electrode 204-1 and the anode electrode 205 are connected to the DC high voltage power supply 211, and a high voltage is applied between the two electrodes to perform electrophoresis of the sample.

[0296] Electrophoretic analysis using such an autosampler-less capillary electrophoresis apparatus can achieve electrophoretic performance equivalent to that of conventional capillary electrophoresis apparatuses. At the same time, it eliminates the need for the autosampler that is standard in conventional capillary electrophoresis apparatuses, thus enabling cost reduction and miniaturization of the apparatus. The endline valve functions effectively, allowing the cathode buffer solution 221 introduced into the cathode block 206 from the inlet 217 and the cathode buffer solution 221 remaining inside to merge into a single continuous solution without the introduction of air bubbles, thus enabling stable analysis.

[0297] <Configuration of Autosampler-less Multi-Capillary Electrophoresis Apparatus> The autosampler-less capillary electrophoresis apparatuses (1), (2), and (3) using a single capillary, as shown in Figures 28A, 28B, and 28C, can be expanded into an autosampler-less multi-capillary electrophoresis apparatus using multiple capillaries. The number of capillaries is not particularly limited.

[0298] Figure 29B shows the structure of the cathode block of an autosampler-less multi-capillary electrophoresis apparatus according to an embodiment of the present invention. Figure 29B shows an example of a configuration with multiple capillaries, specifically one with three capillaries. Figure 29A is a cross-sectional view of the vicinity of the cathode block 206 of Figure 28C, observed from above. Similarly, Figure 29B is a cross-sectional view of the vicinity of the cathode block 206, observed from above, when Figure 28C is extended to an autosampler-less multi-capillary electrophoresis apparatus with three capillaries.

[0299] Note that a cross-sectional view of an autosampler-less multi-capillary electrophoresis apparatus using multiple capillaries, viewed from the side, will appear the same as Figure 28C because the multiple capillaries overlap. Therefore, Figure 28C will be used as a substitute in the following explanation. The number of capillaries can be expanded from three to any number of two or more.

[0300] As shown in Figure 29B, the cathode ends 202-1, 202-2, and 202-3 of the three capillaries 201-1, 201-2, and 202-3 are connected to three channels 216-1, 216-2, and 216-3 inside the cathode block 206, respectively. Meanwhile, the anode ends 203-1, 203-2, and 203-3 are bundled together and connected to a channel 223 inside the anode block 207 (not shown). The cathode block 206 and anode block 207 can be made of transparent acrylic resin to allow observation of the interior.

[0301] The three channels 216-1, 216-2, and 216-3 inside the cathode block 206 extend parallel to each other from three inlets 217-1, 217-2, and 217-3, respectively, and merge into a single channel 216 at confluence point 232. Thereafter (downstream of confluence point 232), the single channel 216 splits into two at branching point 218, similar to Figure 28C for a single capillary. One of the two branches connects to the cathode buffer solution tank system 212. The other branch connects to the waste liquid tank system 213.

[0302] Various gases and liquids, such as air, buffer solution, sample solution, and water, can be individually and independently introduced into the three channels 216-1, 216-2, and 216-3 inside the cathode block 206 from their respective inlets 217-1, 217-2, and 217-3.

[0303] The cathode end 202-1 of the first capillary 201-1 is positioned in the channel 216-1 between the first inlet 217-1 and the confluence point 232. The second cathode electrode 204-2 is positioned in the channel 216-1 between the position where the first cathode end 202-1 is positioned and the confluence point 232.

[0304] The cathode end 202-2 of the second capillary 201-2 is positioned in the channel 216-2 between the second inlet 217-2 and the confluence point 232. The second cathode electrode 204-2 is positioned in the channel 216-2 between the position where the second cathode end 202-2 is positioned and the confluence point 232.

[0305] The cathode end 202-3 of the third capillary 201-3 is positioned in the channel 216-3 between the third inlet 217-3 and the confluence point 232. The second cathode electrode 204-2 is positioned in the channel 216-3 between the position where the third cathode end 202-3 is positioned and the confluence point 232.

[0306] The three second cathode electrodes 204-2, each connected to one of the three flow paths 216-1, 216-2, and 216-3 inside the cathode block 206, are common electrodes that are electrically connected to each other and used in common.

[0307] The three channels 216-1, 216-2, and 216-3 inside the cathode block 206, and the single integrated channel 216, are filled with cathode buffer solution 221 during electrophoresis, etc. The cathode buffer solution tank is filled with cathode buffer solution 221 and air during electrophoresis, etc. The waste liquid tank is filled with waste liquid 215 containing cathode buffer solution 221 and air after the completion of electrophoresis, etc.

[0308] The cathode buffer solution tank system 212 can be configured in any of the configurations shown in Figures 4 to 20, but the following description will use the configuration shown in Figure 18. However, Figure 28C shows a simplified version of the configuration in Figure 18. Without using the external flow path 2-1 (tube 5) and ferrule 12 in Figure 18, the internal flow path 2-2 (hole 4) of the cathode buffer solution tank system 212 and the internal flow path 216 of the cathode block 206 are directly connected, and an end line valve 219 is provided at the boundary between them.

[0309] In Figure 28C, the endline valve 219 is in the "valve open" position. Atmospheric air is supplied into the cathode buffer solution tank from a channel (not shown) corresponding to the external channel 2-3 (tube 5) connected to the lid 11 in Figure 18, so that the inside of the solution tank is maintained at atmospheric pressure.

[0310] The wastewater tank system 213 can be configured in any of the configurations shown in Figures 4 to 20, but the following description will use the configuration shown in Figure 19. However, Figure 28C shows a simplified version of the configuration in Figure 19. Without using the external flow path 2-1 (tube 5) and ferrule 12 in Figure 19, the internal flow path 2-2 (hole 4) of the wastewater tank system 213 and the internal flow path 216 of the cathode block 206 are directly connected, and an end line valve 220 is provided at the boundary between them.

[0311] In Figure 28C, the endline valve 220 is in the "valve closed" state. Atmospheric air is supplied to the inside of the waste liquid tank from a channel (not shown) corresponding to the external channel 2-3 (tube 5) connected to the lid 11 in Figure 19, so that the inside of the solution tank is maintained at atmospheric pressure.

[0312] A cylinder 224, which constitutes a plunger pump, is formed at one end of the flow path 223 inside the anode block 207. The outer end of the cylinder 224 is sealed by a seal portion 227 that functions as a piston. The movement of the seal portion 227 relative to the cylinder 224 is driven by a plunger 228. In the middle of the flow path 223 inside the anode block 207, the anode ends 203-1, 203-2, and 203-3 of three capillaries 201-1, 201-2, and 202-3 are bundled together and connected.

[0313] The inside of the cylinder 224 and the channel 223 is filled with polymer solution 226 during electrophoresis, etc. The inside of the anode buffer solution tank is filled with anode buffer solution 222 and air during electrophoresis, etc. The other end of the channel 223 inside the anode block 207 is connected to the anode buffer solution tank system 214. The anode buffer solution tank system 214 includes an anode buffer solution tank, an anode electrode 205, an end line valve 225, etc. The anode electrode 205 is immersed in the anode buffer solution inside the anode buffer solution tank.

[0314] The anode buffer solution tank system 214 can be configured in any of the configurations shown in Figures 4 to 20, but the following description will use the configuration shown in Figure 18. However, Figure 28C shows a simplified version of the configuration in Figure 18. Without using the external flow path 2-1 (tube 5) and ferrule 12 in Figure 18, the internal flow path 2-2 (hole 4) of the anode buffer solution tank system 214 and the internal flow path 223 of the anode block 207 are directly connected, and an end line valve 225 is provided at the boundary between them.

[0315] In Figure 28C, the endline valve 225 is in the "valve open" position. Atmospheric air is supplied into the anode buffer solution tank from a channel (not shown) corresponding to the external channel 2-3 (tube 5) connected to the lid 11 in Figure 18, so that the inside of the anode buffer solution tank is maintained at atmospheric pressure.

[0316] With the end line valve 225 in the "valve closed" position, the plunger 228 pushes the seal portion 227 into the cylinder 224, applying high pressure to the polymer solution 226 inside the cylinder 224 and the polymer solution 226 inside the flow path 223. This pressure allows the polymer solution 226 to be filled into the three capillaries 201-1, 201-2, and 201-3.

[0317] The cathode buffer solution tank, waste liquid tank, and anode buffer solution tank can all be made of transparent acrylic resin so that their internal components can be observed.

[0318] The first cathode electrode 204-1 and the second cathode electrode 204-2 and the anode electrode 205 are connected to a DC high-voltage power supply 211 via a wire 208. A high voltage is applied between the two electrodes by the DC high-voltage power supply 211 during sample injection and electrophoresis. The first cathode electrode 204-1 and the second cathode electrode 204-2 are grounded, and the anode electrode 205 is subjected to a positive high voltage.

[0319] Switch 209, connected in series with the first cathode electrode 204-1, and switch 210, connected in series with the second cathode electrode 204-2, respectively, switch between connecting and disconnecting the first cathode electrode 204-1 to the DC high voltage power supply 211, or connecting and disconnecting the second cathode electrode 204-2 to the DC high voltage power supply 211.

[0320] In Figure 28C, three capillaries 201-1, 201-2, and 201-3 are connected vertically to the cathode block 206 and anode block 207. Each end of each capillary is connected so as to point vertically downward.

[0321] According to the configuration in Figure 28C, compared to the configuration in Figure 28A, it becomes easier to freely arrange long capillaries. Long capillaries can be curved and connected to the cathode block 206 and anode block 207 from above. Therefore, the degree of design freedom for the autosampler-less capillary electrophoresis apparatus is increased.

[0322] The autosampler-less capillary electrophoresis apparatus shown in Figure 28C differs in structure from the configurations shown in Figures 28A to 28B, and the degree of design freedom for each component differs; however, the performance of capillary electrophoresis with each apparatus is essentially the same. The autosampler-less multi-capillary electrophoresis apparatus shown in Figure 28C offers advantages over the conventional capillary electrophoresis apparatus shown in Figure 2, such as ensuring the airtightness of the solution tank and flow channels, and the arrangement of capillaries and electrodes.

[0323] <Analysis Process Using Autosampler-less Multi-Capillary Electrophoresis Apparatus> Figures 32A to 32Q illustrate the analysis process using an autosampler-less multi-capillary electrophoresis apparatus. Figures 32A to 32Q show the analysis process using an autosampler-less multi-capillary electrophoresis apparatus with three capillaries as shown in Figures 28C and 29B, in chronological order.

[0324] Figures 32A to 32Q show only the cross-sectional view of the cathode block 206, as shown in Figure 29B, viewed from above. The anode block 207 is not shown in Figures 32A to 32Q.

[0325] Figure 32A shows the initial state. All channels 216-1, 216-2, 216-3, and 216 inside the cathode block 206 are filled with cathode buffer solution 221. The cylinder 224 and channel 223 inside the anode block 207 are filled with polymer solution 226. The end line valve 219 of the cathode buffer solution tank system 212 is "valve open", the end line valve 220 of the waste liquid tank system 213 is "valve closed", and the end line valve 225 of the anode buffer solution tank system 214 is "valve open".

[0326] Figure 32B shows the process of filling three capillaries with polymer solution. The end line valve 219 of the cathode buffer solution tank system 212 is "closed", the end line valve 220 of the waste liquid tank system 213 is "open", and the end line valve 225 of the anode buffer solution tank system 214 is "closed". In this state, the plunger 228 is pushed into the inside of the cylinder 224 with a constant load by a single-axis stage driven by a stepping motor. This load is applied to the polymer solution 226 inside the cylinder 224 and the polymer solution 226 inside the flow path 223 via the seal portion 227. The polymer solution 226 becomes, for example, a high-pressure polymer solution 301 at 35 atmospheres. The end line valve 225 is provided with high pressure resistance to prevent leakage of the high-pressure polymer solution 301. On the other hand, in the cathode block 206, the cathode buffer solution 221 inside the flow path 216 is at atmospheric pressure. Due to this pressure difference between the two ends, polymer solution 226 fills the inside of each capillary 201-1, 201-2, and 201-3 from the anode ends 203-1, 203-2, and 203-3 toward the cathode ends 202-1, 202-2, and 202-3.

[0327] Figure 32C shows the process of performing preliminary electrophoresis. The end line valve 219 of the cathode buffer solution tank system 212 is set to "open", the end line valve 220 of the waste liquid tank system 213 is set to "closed", and the end line valve 225 of the anode buffer solution tank system 214 is set to "open". With this in place, switch 209 is turned ON, the first cathode electrode 204-1 and the anode electrode 205 are connected to the DC high voltage power supply 211, and a high voltage is applied between the two electrodes to perform preliminary electrophoresis.

[0328] Figures 32D to 32J show the process of performing electric field implantation of three types of samples. As shown in Figure 32D, the end line valve 219 of the cathode buffer solution tank system 212 is "closed", the end line valve 220 of the waste liquid tank system 213 is "open", and the end line valve 225 of the anode buffer solution tank system 214 is "open". In this state, air 302 is introduced from the inlet 217-1 into the first flow path 216-1 inside the cathode block 206, and the cathode buffer solution 221 inside the first flow path 216-1 and the flow path 216 after merging is discharged into the waste liquid tank, replacing the inside of the first flow path 216-1 and the flow path 216 after merging with air 302. However, since the endline valve 219 is "valve closed," the inside of the flow path 216 between the branching point 218 and the cathode buffer solution tank system 212 remains filled with the cathode buffer solution 221.

[0329] Next, as shown in Figure 32E, air 302 is introduced from the inlet 217-2 into the second channel 216-2 inside the cathode block 206, discharging the cathode buffer solution 221 inside the second channel 216-2 and the air 302 inside the channel 216 after the merge into the waste liquid tank, thereby replacing the inside of the second channel 216-2 and the channel 216 after the merge with air 302. However, since the end line valve 219 is "valve closed", the inside of the channel 216 between the branching point 218 and the cathode buffer solution tank system 212 is maintained to be filled with cathode buffer solution 221.

[0330] Next, as shown in Figure 32F, air 302 is introduced from inlet 217-3 into the third channel 216-3 inside the cathode block 206, discharging the cathode buffer solution 221 inside the third channel 216-3 and the air 302 inside the channel 216 after the merge into the waste liquid tank, thereby replacing the inside of the third channel 216-3 and the channel 216 after the merge with air 302. However, since the end line valve 219 is "valve closed", the inside of the channel 216 between the branching point 218 and the cathode buffer solution tank system 212 is maintained to be filled with cathode buffer solution 221.

[0331] Next, as shown in Figure 32G, the first sample solution 303-1 is introduced into the first channel 216-1 inside the cathode block 206 from the inlet 217-1, so that the first sample solution 303-1 (sample 1) comes into contact with the cathode end 202-1 of the first capillary 201-1 and the second cathode electrode 204-2, and the downstream end of the first sample solution 303-1 is positioned between the second cathode electrode 204-2 and the confluence point 232. At this time, some of the air 302 inside the first channel 216-1 and the channel 216 after the confluence is discharged into the waste liquid tank. Since the end line valve 219 is "valve closed", the inside of the channel 216 between the branching point 218 and the cathode buffer solution tank system 212 is maintained to be filled with cathode buffer solution 221.

[0332] Next, as shown in Figure 32H, the second sample solution 303-2 (sample 2) is introduced into the second channel 216-2 inside the cathode block 206 from the inlet 217-2, so that the second sample solution 303-2 comes into contact with the cathode end 202-2 of the second capillary 201-2 and the second cathode electrode 204-2, and the downstream end of the second sample solution 303-2 is positioned between the second cathode electrode 204-2 and the confluence point 232. At this time, some of the air 302 inside the second channel 216-2 and the channel 216 after the confluence is discharged into the waste liquid tank. Since the end line valve 219 is "valve closed", the inside of the channel 216 between the branching point 218 and the cathode buffer solution tank system 212 is maintained to be filled with cathode buffer solution 221.

[0333] Next, as shown in Figure 32I, the third sample solution 303-3 (sample 3) is introduced into the third channel 216-3 inside the cathode block 206 from the inlet 217-3, so that the third sample solution 303-3 comes into contact with the cathode end 202-3 of the third capillary 201-3 and the second cathode electrode 204-2, and the downstream end of the third sample solution 303-3 is positioned between the second cathode electrode 204-2 and the confluence point 232. At this time, some of the air 302 inside the third channel 216-3 and the channel 216 after the confluence is discharged into the waste liquid tank. Since the end line valve 219 is "valve closed", the inside of the channel 216 between the branching point 218 and the cathode buffer solution tank system 212 is maintained to be filled with cathode buffer solution 221.

[0334] Next, as shown in Figure 32J, the end line valve 219 of the cathode buffer solution tank system 212 is set to "closed", the end line valve 220 of the waste liquid tank system 213 is set to "closed", and the end line valve 225 of the anode buffer solution tank system 214 is set to "open". In this state, the switch 210 is turned ON, the second cathode electrode 204-2 and the anode electrode 205 are connected to the DC high voltage power supply 211, and a high voltage is applied between the two electrodes to simultaneously perform electric field injection of the first sample solution 303-1 into the first capillary 201-1, electric field injection of the second sample solution 303-2 into the second capillary 201-2, and electric field injection of the third sample solution 303-3 into the third capillary 201-3.

[0335] Figures 32K to 32Q show the process of performing electrophoresis on the sample. As shown in Figure 32K, the end line valve 219 of the cathode buffer solution tank system 212 is "closed", the end line valve 220 of the waste liquid tank system 21 is "open", and the end line valve 225 of the anode buffer solution tank system 214 is "open". In this state, air 302 is introduced into the first channel 216-1 inside the cathode block 206 from the inlet 217-1, and the air 302 and the first sample solution 303-1 inside the first channel 216-1 and the channel 216 after merging are discharged into the waste liquid tank, replacing the inside of these channels 216-1 and 216 with air 302. However, since the endline valve 219 is "valve closed," the inside of the flow path 216 between the branching point 218 and the cathode buffer solution tank system 212 remains filled with the cathode buffer solution 221.

[0336] Next, as shown in Figure 32L, air 302 is introduced from inlet 217-2 into the second channel 216-2 inside the cathode block 206, and the air 302 and the second sample solution 303-2 inside the second channel 216-2 and the channel 216 after the merge are discharged into the waste liquid tank, replacing the inside of these channels 216-2 and 216 with air 302. However, since the end line valve 219 is "valve closed", the inside of the channel 216 between the branching point 218 and the cathode buffer solution tank system 212 is maintained to be filled with cathode buffer solution 221.

[0337] Next, as shown in Figure 32M, air 302 is introduced from inlet 217-3 into the third channel 16-3 inside the cathode block 206, and the air 302 and the third sample solution 303-3 inside the third channel 216-3 and the channel 216 after the merge are discharged into the waste liquid tank, replacing the inside of these channels 216-3 and 216 with air 302. However, since the end line valve 219 is "valve closed", the inside of the channel 216 between the branching point 218 and the cathode buffer solution tank system 212 is maintained to be filled with cathode buffer solution 221.

[0338] Next, as shown in Figure 32N, cathode buffer solution 221 is introduced from inlet 217-1 into the first channel 16-1 inside the cathode block 206, and the air 302 inside the first channel 216-1 and the channel 216 after merging is discharged into the waste liquid tank, replacing the inside of these channels 216-1 and 216 with cathode buffer solution 221. The cathode buffer solution 221 introduced from inlet 217-1 is merged with the cathode buffer solution 221 remaining inside the channel 216 between the branching point 218 and the cathode buffer solution tank system 212 without introducing air bubbles.

[0339] Next, as shown in Figure 32O, cathode buffer solution 221 is introduced from inlet 217-2 into the second channel 16-2 inside the cathode block 206, and the air 302 inside the second channel 216-2 and the channel 216 after merging is discharged into the waste liquid tank, replacing the inside of these channels 216-2 and 216 with cathode buffer solution 221. The cathode buffer solution 221 introduced from inlet 217-2 is merged with the cathode buffer solution 221 remaining inside the channel 216 between the branching point 218 and the cathode buffer solution tank system 212 without introducing air bubbles.

[0340] Next, as shown in Figure 32P, cathode buffer solution 221 is introduced from inlet 217-3 into the third channel 16-3 inside the cathode block 206, and the air 302 inside the third channel 216-3 and the channel 216 after merging is discharged into the waste liquid tank, replacing the inside of these channels 216-3 and 216 with cathode buffer solution 221. The cathode buffer solution 221 introduced from inlet 217-3 is merged with the cathode buffer solution 221 remaining inside the channel 216 between the branching point 218 and the cathode buffer solution tank system 212 without introducing air bubbles.

[0341] Next, as shown in Figure 32Q, the end line valve 219 of the cathode buffer solution tank system 212 is set to "open," the end line valve 220 of the waste liquid tank system 213 is set to "closed," and the end line valve 225 of the anode buffer solution tank system 214 is set to "open." With this setup, switch 209 is turned ON, the first cathode electrode 204-1 and the anode electrode 205 are connected to the DC high-voltage power supply 211, and a high voltage is applied to both electrode ends to perform electrophoresis of the sample.

[0342] Electrophoretic analysis using such an autosampler-less multi-capillary electrophoresis system can achieve electrophoretic performance equivalent to that of conventional capillary electrophoresis systems. At the same time, it eliminates the need for the autosampler that is standard in conventional capillary electrophoresis systems, thus enabling cost reduction and miniaturization of the system. The endline valve functions effectively, allowing the cathode buffer solution 221 introduced into the cathode block 206 from the inlet 217 and the cathode buffer solution 221 remaining inside to merge into a single continuous solution without the introduction of air bubbles. This enables parallel and stable analysis using multiple capillaries.

[0343] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention. For example, the present invention is not necessarily limited to having all the configurations of the embodiments described above. Some configurations of one embodiment can be replaced with other configurations, some configurations of one embodiment can be added to other forms, and some configurations of one embodiment can be omitted.

[0344] 1 Flow channel material 2 Flow channel 2-1 Flow channel 2-2 Flow channel 2-3 Flow channel 2-4 Flow channel 2-5 Flow channel 2-6 Flow channel 3 Anode buffer solution tank 4 Hole 5 Tube 6 In-line valve 7 End-line valve 8 Solution 8-1 Polymer solution 8-2 Anode buffer solution 8-3 Waste liquid 9 Liquid level 10 Air 11 Lid 12 Ferrule 13 Pin 14 Head section 15 Tip section 16-1 O-ring 16-2 O-ring 16-3 O-ring 16-4 O-ring 16-5 O-ring 17 Electrode 18 Spring 19 Pressure-controlled air 20 Through hole 22 Enlarged diameter section 23-1 Valve 23-2 Valve 23-3 Valve 25 Screw 26 Auxiliary solution tank 27 Hydrophobic filter 28 Liquid level 101 Capillary 102 Cathode end 103 Anode end 104 Detection position 105 Cathode electrode 106 Anode electrode 107 Wire 108 DC high voltage power supply 109 Cathode buffer solution tank 110 Cathode buffer solution 111 Sample solution tank 112 Sample solution 113 O-ring 114 Cathode stage 115 Fixing block 116 Flow path 117 Connector 118 Anode block 119 Pressure-resistant syringe 120 Plunger 121 Polymer solution 122 Flow path 123 Anode buffer solution tank 124 Lid 125 Anode buffer solution 126 Flow path 127 Pin 128 End line valve 129 Air tube 130 Air source 131 Valve 132 Valve 133 Valve 134 Valve 135 Laser light source 136 Laser beam 137 Flow channel 138 Air 139 Switch 140 High-pressure polymer solution 141 High-pressure air 201 Capillary 201-1 Capillary 201-2 Capillary 201-3 Capillary 202 Cathode terminal 202-1 Cathode terminal 202-2 Cathode terminal 202-3 Cathode terminal 203 Anode terminal 203-1 Anode terminal 203-2 Anode terminal 203-3 Anode terminal 204-1 First cathode electrode 204-2 Second cathode electrode 205 Anode electrode 206 Cathode block 207 Anode block 208 Wire 209 Switch 210 Switch 211 DC high-voltage power supply212 Cathode buffer solution tank system 213 Waste liquid tank system 214 Anode buffer solution tank system 215 Waste liquid 216 Flow path 216-1 Flow path 216-2 Flow path 216-3 Flow path 217 Inlet 217-1 Inlet 217-2 Inlet 217-3 Inlet 218 Branch point 219 End line valve 220 End line valve 221 Cathode buffer solution 222 Anode buffer solution 223 Flow path 224 Cylinder 225 End line valve 226 Polymer solution 227 Seal section 228 Plunger 229 Flow path 230 Flow path 231 Flow path 232 Confluence point

Claims

1. A solution tank system comprising: a first solution tank containing a first solution and a first air; a lid that closes the opening at the upper end of the first solution tank; a first flow path that enters from the outside of the first solution tank into the bottom of the first solution tank from the bottom surface of the first solution tank, extends vertically upward through the interior of the bottom, widens in an inverse tapered shape toward the interior of the first solution tank and terminates therein, containing a second solution; and a first valve that opens and closes the end of the first flow path, wherein the first valve has a pin with a tapered tip that penetrates the lid and enters the interior of the first solution tank, the first solution and the second solution can merge at the end of the first flow path, when the pin is moved downward, the tip of the pin closes the end and the first valve closes, and when the pin is moved upward, the tip of the pin separates from the end and the first valve opens.

2. The solution tank system according to claim 1, characterized in that it comprises an electrode immersed in the first solution.

3. The solution tank system according to claim 1, characterized in that the first solution tank and the lid are fixed to each other with screws.

4. A solution tank system according to any one of claims 1 to 3, characterized in that when the first valve is open, the pin is immersed in the first solution.

5. The solution tank system according to claim 4, characterized in that when the first valve is open, the tip of the pin is inserted into the portion of the first flow path that widens in an inverse tapered shape.

6. The solution tank system according to claim 4, characterized in that a sealing member is compressed between the upper surface of the side wall of the first solution tank and the lower surface of the lid, thereby sealing the gap between the upper surface of the side wall of the first solution tank and the lower surface of the lid.

7. A solution tank system according to claim 4 or claim 6, wherein the pin has an enlarged diameter portion between the tip of the pin and the lower surface of the lid, and when the first valve is open, a sealing member is compressed between the upper surface of the enlarged diameter portion and the lower surface of the lid, thereby sealing the gap between the pin inserted through the through hole provided in the lid and the through hole.

8. A solution tank system according to claim 4 or claim 6, wherein the pin has an enlarged diameter portion between the rear end of the pin and the upper surface of the lid, and when the first valve is closed, a sealing member is compressed between the lower surface of the enlarged diameter portion and the upper surface of the lid, thereby sealing the gap between the pin inserted through the through hole provided in the lid and the through hole.

9. A solution tank system according to claim 4 or claim 6, characterized in that when the first valve is open, when the first valve is closed, or when the first valve is at an intermediate opening, a sealing member is compressed between the side surface of the pin inserted through the through hole provided in the lid and the inner wall of the through hole, thereby sealing the gap between the pin and the through hole.

10. A solution tank system according to any one of claims 1 to 3, comprising a second flow path containing second air that enters from outside the first solution tank into the inside of the lid or the inside of the side wall of the first solution tank and terminates inside the first solution tank, wherein the first air and the second air merge at the end of the second flow path.

11. The solution tank system according to claim 10, characterized in that the second air is air under atmospheric pressure.

12. The solution tank system according to claim 10, characterized in that the second air is pressure-controlled air.

13. A solution tank system according to claim 11 or claim 12, characterized in that a second valve for opening and closing the second flow path is provided on the second flow path.

14. The solution tank system according to claim 4, characterized in that the pin has an enlarged diameter portion between the tip of the pin and the lower surface of the lid, the pin has a head portion with an enlarged outer diameter at its rear end, and a compressed spring is installed between the lower surface of the head portion and the upper surface of the lid.

15. A solution tank system according to any one of claims 1 to 3, comprising a second solution tank containing a third solution and a third air outside the first solution tank, the first solution tank and the second solution tank being connected to each other via a third flow path, with one end of the third flow path designated as a first end and the other end of the third flow path designated as a second end, wherein one end of the third flow path enters from outside the first solution tank into the inside of the lid or the inside of the side wall of the first solution tank, and the first end is located inside the first solution tank, the other end of the third flow path enters from outside the second solution tank into the inside of the second solution tank, and the second end is located inside the second solution tank, the height of the first end is higher than the height of the second end, and the height of the liquid level of the first solution is higher than the height of the liquid level of the third solution.

16. The solution tank system according to claim 15, characterized in that the surface of the second solution tank is provided with a filter that is permeable to gas and poorly permeable to liquid.

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