Pipetting capillary tube and capillary tube micro-sampling device

Abstract

The utility model belongs to the technical field of water quality detection equipment, and discloses a pipetting capillary tube and a capillary tube micro-sampling device. The pipetting capillary tube comprises a first straight tube, a second straight tube and a middle tube, the first straight tube is arranged in the vertical direction, and a liquid taking opening is formed in the bottom end of the first straight tube; the second straight pipe and the first straight pipe are arranged at intervals and are parallel to each other; a liquid outlet is formed in the bottom end of the second straight pipe; the middle pipe comprises an upper bent pipe with a downward opening, the two ends of the upper bent pipe are connected with the top end of the first straight pipe and the top end of the second straight pipe respectively and communicate with each other, and under the action of capillary force, liquid can pass through the liquid taking opening, sequentially passes through the first straight pipe, the middle pipe and the second straight pipe and is discharged from the liquid outlet; the first straight pipe, the second straight pipe and the middle pipe are all capillary pipes. According to the utility model, liquid taking and liquid transferring processes can be realized without external force moving and driving, so that the problem of liquid spilling in the liquid transferring process is avoided, and the problems of environmental pollution in detection and insufficient accuracy of trace liquid transferring during sampling are further solved.

Description

Technical Field

[0001] The utility model relates to the technical field of water quality detection equipment, in particular to a pipetting capillary and a capillary micro-sampling device. Background Art

[0002] In existing water quality testing equipment, micro-sampling of water is required. Micro-liquid drives include capillary force drive, external force (air pressure, electric force, magnetic force) drive, mechanical (pump, microneedle) drive, and microfluidic chip technology drive. Among them, the drive scenarios of capillary force and microfluidic chip technology can accurately control the amount of liquid movement, but there are problems with cleaning. The liquid object to be moved cannot be reused or changed immediately. The same capillary cannot meet the conditions for instantly moving different types of liquids. In addition, after capillary sampling, there may be droplet loss in the pipetting process, causing pollution to the detection environment. It is not enough to meet the actual use requirements of micro-pipetting accuracy in different scenarios. Utility Model Content

[0003] The utility model aims to provide a pipetting capillary and a capillary micro-sampling device, which are used to solve the problems of easy detection environment pollution and insufficient micro-pipetting accuracy during capillary micro-sampling.

[0004] To achieve this purpose, the present invention adopts the following technical solutions:

[0005] The utility model provides a liquid transfer capillary, comprising:

[0006] A first straight tube, the first straight tube is arranged in a vertical direction, and the bottom end of the first straight tube is a liquid intake port;

[0007] a second straight tube, the second straight tube being spaced apart from and parallel to the first straight tube, the bottom end of the second straight tube being a liquid outlet;

[0008] an intermediate tube, the intermediate tube comprising an upper curved tube with a downward opening, the ends of the upper curved tube being connected to the top ends of the first straight tube and the second straight tube, respectively, and being arranged in communication with each other, so that under the action of capillary force, liquid can pass through the liquid inlet and sequentially pass through the first straight tube, the intermediate tube, and the second straight tube to be discharged from the liquid outlet;

[0009] The first straight tube, the second straight tube and the middle tube are all capillary tubes.

[0010] In some embodiments, the intermediate tube includes an upper bend tube and a lower bend tube with an upward opening, the two ends of the lower bend tube are respectively connected to the two upper bend tubes, and the ends of the two upper bend tubes facing away from the lower bend tube are respectively connected to the top of the first straight tube or the second straight tube.

[0011] In some embodiments, the intermediate tube includes an upper bend tube, a lower bend tube and a third straight tube. The third straight tube is arranged between the first straight tube and the second straight tube. The third straight tube and the first straight tube are arranged parallel to each other. The two ends of the third straight tube are respectively connected to an upper bend tube and a lower bend tube.

[0012] In some embodiments, when the intermediate tube includes two or more upper curved tubes, the top ends of the plurality of upper curved tubes decrease in height sequentially from the first straight tube to the first straight tube.

[0013] In some embodiments, the axes of the upper curved tube and the lower curved tube are both semicircular arc shapes.

[0014] In some embodiments, the pipetting capillary is a one-piece structure capillary.

[0015] In some embodiments, the pipetting capillary further includes a cleaning device, which is disposed on the intermediate tube.

[0016] In some embodiments, the pipetting capillary further includes a suction device, which is disposed on the intermediate tube and configured to suck the liquid at the liquid extraction port into the intermediate tube.

[0017] The present utility model also provides a capillary micro-sampling device, comprising a liquid reservoir, a dripping area, and the pipetting capillary provided in any of the above embodiments, wherein the first straight tube of the pipetting capillary extends from top to bottom into the liquid reservoir, and the height of the liquid in the liquid reservoir satisfies that the liquid can at least reach the highest point of the pipetting capillary under the action of capillary force, and the liquid outlet of the second straight tube of the pipetting capillary is arranged directly opposite the dripping area.

[0018] In some embodiments, the liquid storage tank is provided with a sampling port at the top and a liquid inlet at the side. The first straight tube passes through the sampling port and is sealed with the sampling port. The liquid inlet is used to replenish the liquid in the liquid storage tank.

[0019] Beneficial effects of the utility model:

[0020] The pipetting capillary provided by the utility model, by arranging an intermediate tube between two mutually parallel first straight tubes and second straight tubes, can realize the liquid collection and pipetting process between the first straight tube and the second straight tube arranged at intervals without the need for external force to move and drive, thereby avoiding the problem of liquid spillage, and further solving the problem of detection environmental pollution during sampling; the pipetting capillary of the utility model adopts a capillary tube and uses capillary force to perform micro-liquid collection and pipetting, which can accurately obtain the sampling amount of micro-liquid for detection, and solves the problem of insufficient accuracy of micro-pipetting.

[0021] The capillary micro-sampling device provided by the utility model arranges a pipetting capillary between the liquid storage tank and the dripping area, so that the liquid in the liquid storage tank can be transferred from the liquid storage tank to the dripping area under the action of capillary force, thereby realizing no external force drive, no spillage and trace liquid sampling, solving the problem of liquid pollution in the water quality detection process and improving the sampling accuracy of trace liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic structural diagram of a pipetting capillary provided in Example 1 of the present utility model;

[0023] Figure 2 This is a schematic structural diagram of a pipetting capillary provided in Example 2 of the present utility model;

[0024] Figure 3 This is a schematic structural diagram of a pipetting capillary provided in Example 3 of the present utility model;

[0025] Figure 4 This is a schematic structural diagram of a pipetting capillary provided in a third embodiment of the present invention, in which a cleaning device and a suction device are provided;

[0026] Figure 5 This is a schematic structural diagram of a capillary micro-sampling device provided in Example 4 of the present utility model;

[0027] Figure 6 It is a cross-sectional view of the installation structure of the pipetting capillary and the liquid storage tank in the capillary micro-sampling device provided in the fourth embodiment of the present invention.

[0028] In the picture:

[0029] 1. First straight tube; 11. Liquid collection port; 2. Second straight tube; 21. Liquid outlet; 3. Intermediate tube; 31. Upper curved tube; 32. Lower curved tube; 33. Third straight tube; 4. Cleaning device; 5. Suction device; 6. Liquid storage tank; 61. Sampling port; 62. Liquid inlet; 7. Drip area; 8. Sealing ring. DETAILED DESCRIPTION

[0030] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all of its components.

[0031] In the description of this utility model, unless otherwise specified or limited, the terms "connected," "connect," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0032] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0033] In the description of this embodiment, terms such as "upper," "lower," and "right" are used to refer to positions or locations based on the positions or locations shown in the accompanying drawings. These terms are intended solely to facilitate description and simplify operation, and are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meaning.

[0034] Example 1:

[0035] This embodiment provides a pipetting capillary, including a first straight tube 1, a second straight tube 2 and an intermediate tube 3. The first straight tube 1 is arranged in a vertical direction, and the bottom end of the first straight tube 1 is a liquid intake port 11; the second straight tube 2 is arranged at an interval and parallel to the first straight tube 1, and the bottom end of the second straight tube 2 is a liquid outlet 21; the intermediate tube 3 includes an upper curved tube 31 with an opening facing downward, and the two ends of the upper curved tube 31 are respectively connected to the top of the first straight tube 1 and the top of the second straight tube 2 and are connected. Under the action of capillary force, the liquid can pass through the liquid intake port 11 and pass through the first straight tube 1, the intermediate tube 3 and the second straight tube 2 in sequence to be discharged from the liquid outlet 21; the first straight tube 1, the second straight tube 2 and the intermediate tube 3 are all capillaries.

[0036] The pipetting capillary provided by the present invention, by setting an intermediate tube 3 between two mutually parallel first straight tubes 1 and second straight tubes 2, can realize the process of taking liquid and pipetting between the spaced first straight tubes 1 and second straight tubes 2 without the need for external force to move and drive, thereby avoiding the problem of liquid spillage, and thus solving the problem of detection environmental pollution during sampling; the pipetting capillary of the present invention uses a capillary and uses capillary force to perform micro-liquid pipetting, which can accurately obtain the sampling amount of micro-liquid for detection, solving the problem of insufficient accuracy of micro-pipetting. It can be understood that the first straight tube 1 and the second straight tube 2 are spaced apart, so that the sampling port 61 and the liquid outlet 21 can be spaced apart, effectively avoiding the problem that the liquid will splash to the liquid outlet 21 during the sampling process, affecting the liquid accuracy of the liquid outlet 21, and avoiding the problem of spillage during liquid pipetting. It should be noted that the liquid level rise height h at the liquid outlet 11 of the first straight tube 1 is affected by factors such as the inner pore diameter r of the capillary, the surface tension of the liquid and the density of the liquid. The specific influencing relationship is as follows:

[0037]

[0038] Where γ is the surface tension coefficient of the liquid, θ is the contact angle, ρ is the liquid density, g is the acceleration due to gravity, and r is the inner diameter of the capillary. Under ideal conditions, the energy E in the pipetting capillary is 毛细作用 The conversion can be obtained by the following formula:

[0039]

[0040] Where m is the mass of the liquid, g is the acceleration due to gravity, h is the max is the highest height in the pipetting capillary, v is the flow rate of the liquid in the pipetting capillary, and h is the height of the liquid in the pipetting capillary.

[0041] It can be understood that according to the capillary phenomenon of the liquid taking port 11, the first straight tube 1 absorbs the liquid, and the liquid moves in the pipetting capillary through the gravity and inertia of the liquid itself until the liquid outlet 21 is used to take the liquid (sampling) and pipette.

[0042] The inner surface of the pipette capillary needs to be smooth and flat to reduce energy loss caused by resistance interference such as friction.

[0043] In this embodiment, the first straight tube 1, second straight tube 2, and intermediate tube 3 in the pipette capillary can be of constant diameter or variable diameter. The inner diameter of the capillary can be adjusted based on the required liquid volume and pipetting speed. The pipette capillary can be made of plastic, metal, or composite materials, resulting in varying internal friction. The inner wall of the pipette capillary can be coated with a smooth antibacterial coating to improve the pipette's service life and sampling accuracy.

[0044] Example 2:

[0045] This embodiment provides a pipetting capillary. Based on the first embodiment, the intermediate tube 3 further includes a lower curved tube 32 with an upward opening. The two ends of the lower curved tube 32 are respectively connected to the ports of the two upper curved tubes 31 facing away from the first straight tube 1 or the second straight tube 2.

[0046] like Figure 2 As shown, the middle tube 3 includes two upper curved tubes 31 and a lower curved tube 32. The two ends of the lower curved tube 32 are respectively connected to an upper curved tube 31. The ends of the two upper curved tubes 31 facing away from the lower curved tube 32 are respectively connected to the first straight tube 1 and the second straight tube 2. The liquid entering from the liquid taking port 11 can reach the top of the first upper curved tube 31 from the first straight tube 1 under the action of capillary force. Under the action of liquid gravity and inertia, the liquid passes through the first upper curved tube 31, the lower curved tube 32, the second upper curved tube 31 and the second straight tube 2, and drips out from the liquid outlet 21, realizing the movement of liquid from the sampling port 61 to the liquid outlet 21. Figure 2 As shown, there is a height difference Δh between the maximum heights of the two upper curved tubes 31. Considering the energy loss caused by friction and wear of the liquid within the capillary tube, the maximum height of the second upper curved tube 31 is lowered to ensure that the liquid can overcome the height difference between the lower curved tube 32 and the upper curved tube 31 to achieve liquid transfer. Of course, in other embodiments, energy loss can also be overcome by setting a difference in the aperture of the upper curved tube 31 and the lower curved tube 32.

[0047] Example 3:

[0048] This embodiment is a further improvement on the basis of the second embodiment. On the basis of the second embodiment, the intermediate tube 3 further includes a third straight tube 33. The third straight tube 33 is arranged between the first straight tube 1 and the second straight tube 2. The third straight tube 33 and the first straight tube 1 are arranged parallel to each other. The two ends of the third straight tube 33 are respectively connected to an upper curved tube 31 and a lower curved tube 32.

[0049] like Figure 3 As shown, the pipetting capillary is provided with a first straight tube 1, a first upper curved tube 31, a third straight tube 33, a lower curved tube 32, a second upper curved tube 31 and a second straight tube 2 in sequence along the direction of liquid movement. It can be understood that the third straight tube 33 increases the height difference △h between the two upper curved tubes 31, which is more conducive to the movement of liquid in the capillary.

[0050] It should be noted that when the distance between the liquid taking port 11 and the liquid outlet 21 is large, that is, the liquid needs to move a long distance to achieve liquid taking and pipetting, by setting the third straight tube 33, the number of upper curved tubes 31 can be increased within the range of the height difference △h, thereby increasing the pipetting distance. Figure 3A third straight tube 33 can be added between the middle lower bend tube 32 and the second upper bend tube 31 without exceeding the maximum height, so as to achieve long-distance liquid extraction and pipetting of multiple upper bend tubes 31 with successive heights.

[0051] In some embodiments, when the intermediate tube 3 includes more than two upper curved tubes 31 , the top ends of the plurality of upper curved tubes 31 decrease in height sequentially from one straight tube 1 to another.

[0052] In some embodiments, the axes of the upper curved tube 31 and the lower curved tube 32 are both semicircular arc shapes.

[0053] like Figure 3 As shown, the axes of the upper curved tube 31 and the lower curved tube 32 are configured as semicircular arcs, facilitating transitional connections with the first straight tube 1, the second straight tube 2, and the third straight tube 33, as well as the connection between the upper curved tube 31 and the lower curved tube 32, thereby reducing energy loss and facilitating liquid movement. It should be noted that by adjusting the diameters or arc segments of the multiple upper curved tubes 31 to different values, the difference between the highest points of any two upper curved tubes 31 can be controlled, facilitating liquid movement within the capillary tube.

[0054] In some embodiments, the pipetting capillary is an integrated structure capillary. The integrated structure can reduce the friction of the liquid on the inner wall of the capillary, and the one-step molding process is simple, and the structure has good sealing and consistency.

[0055] In some embodiments, the pipetting capillary further includes a cleaning device 4 , which is disposed on the intermediate tube 3 .

[0056] like Figure 4 As shown, in this embodiment, the cleaning device 4 is arranged on the intermediate tube 3. In this embodiment, the cleaning device 4 is arranged on the first upper curved tube 31. After the liquid is pipetted, the capillary portion of the pipetting capillary can be cleaned by the cleaning device 4. The cleaning device 4 can clean by blowing air or spraying water into the capillary. The airflow or water flow can carry away any liquid that may remain on the inner wall of the capillary. At the same time, the high-temperature gas or liquid sterilizes to achieve deep cleaning. The nozzle of the cleaning device 4 is arranged on the first upper curved tube 31, so that the cleaning gas or cleaning liquid can flow to both sides of the capillary light to clean, which is conducive to improving the cleaning effect and efficiency. The connection between the cleaning device 4 and the upper curved tube 31 (capillary) is provided with a sealing ring 8. The upper curved tube 31 is reserved for mounting holes during processing. The cleaning device 4 is only installed and cleaned after each liquid is pipetted. It can be removed when not in a clean state. The mounting hole can be sealed with a sealing plug. By setting up the cleaning device 4, the same pipetting capillary can be repeatedly moved with different liquids without being contaminated by the previous liquid.

[0057] In some embodiments, the pipetting capillary further includes a suction device 5 , which is disposed on the intermediate tube 3 . The suction device 5 is configured to suck the liquid at the liquid extraction port 11 into the intermediate tube 3 .

[0058] For example Figure 4 The suction device 5 is arranged on the first upper curved tube 31 and is arranged near the top of the first straight tube 1. The function of the suction device 5 is to suck the liquid at the liquid intake port 11 of the first main tube into the first straight tube 1, so that the liquid can reach the first upper curved tube 31, which is also the upper curved tube 31 with the highest height, so that the liquid can reach the liquid outlet 21 by relying on its own gravity and inertia during the subsequent movement. Among them, the suction device 5 can adopt a liquid inlet pump or a peristaltic pump. On the basis of capillary action, the suction device 5 can further accurately control and move the liquid, improve the liquid collection accuracy and reduce the liquid collection time. The installation method of the suction device 5 is similar to that of the cleaning device 4, and is detachably connected to the pipetting capillary.

[0059] The pipette capillary provided in the above embodiment can be made of materials such as plastic, metal or composite materials, so that the inner wall of the capillary has different friction forces. The inner wall of the pipette capillary can be provided with a smooth antibacterial coating to improve the service life and liquid collection accuracy of the pipette capillary; after removing the cleaning device 4 and the suction device 5, the entire pipette capillary can be sterilized by high-temperature heating.

[0060] Example 4:

[0061] The present invention provides a capillary micro-sampling device, such as Figure 5 and Figure 6 , including a liquid reservoir 6, a dripping area 7 and a pipetting capillary provided by any of the above embodiments, the first straight tube 1 of the pipetting capillary extends from top to bottom into the liquid reservoir 6, the liquid height in the liquid reservoir 6 satisfies that the liquid can reach at least the highest point of the pipetting capillary under the action of capillary force, and the liquid outlet 21 of the second straight tube 2 of the pipetting capillary is arranged opposite to the dripping area 7.

[0062] The capillary micro-sampling device provided by the present utility model has a simple mechanical structure, precise control and small space occupation. By arranging a pipetting capillary between the liquid reservoir 6 and the dripping area 7, the liquid in the liquid reservoir 6 can be transferred from the liquid reservoir 6 to the dripping area 7 under the action of capillary force, realizing no external force driving, no spillage and trace liquid sampling, solving the problem of liquid pollution environment in the water quality detection process, and improving the sampling accuracy of trace liquid. It should be noted that, in the present embodiment, the dripping area 7 is provided with a trough structure for receiving the sampled liquid. According to the specific water quality detection process, the dripping area 7, as the dripping area after the liquid sample is sampled, can be provided with other detection devices with sample suction or sample storage such as test paper, sample pool or cuvette, or can be other indicator carriers for detecting the components of the sampled liquid. When the dripping area 7 is a test paper, the liquid sample to be detected can be directly dripped on the test paper for water quality detection. By setting up the pipetting capillary, when there is a certain distance between the liquid reservoir 6 and the dripping area 7, a trace amount of liquid transfer can be achieved without spilling the liquid during the transfer process, and the liquid splashed from the liquid reservoir 6 can be prevented from affecting the detection results of the dripping area 7.

[0063] In some embodiments, a sampling port 61 is provided at the top of the liquid storage tank 6 and a liquid inlet 62 is provided on the side. The first straight tube 1 passes through the sampling port 61 and is sealedly connected to the sampling port 61. The liquid inlet 62 is used to replenish the liquid in the liquid storage tank 6.

[0064] like Figure 5 and Figure 6 , the sampling port 61 is provided on the top cover of the liquid reservoir 6. When the top cover seals the top of the liquid reservoir 6, the first straight tube 1 extends into the interior of the liquid reservoir 6 through the sampling port 61. The sampling port 61 is provided as a stepped hole. Two sealing rings 8 are provided between the first straight tube 1 and the sampling port 61. The two sealing rings 8 are respectively provided on the inner walls of two different inner holes of the stepped hole to achieve a sealed connection between the first straight tube 1 and the sampling port 61. In some embodiments, at least one sealing ring 8 is also provided on the first straight tube 1 inside the liquid reservoir 6. The sealing ring 8 is used to prevent the first straight tube 1 from being separated from or pulled out of the sampling port 61 under the action of external force. A liquid inlet 62 is provided on the side wall of the liquid reservoir 6. The liquid inlet 62 is connected to the liquid supply end through a liquid inlet pipe for replenishing liquid to the liquid reservoir 6 to ensure that the liquid level in the liquid reservoir 6 can be replenished in time after the liquid transfer causes the liquid level to drop.

[0065] When using this capillary micro-sampling device, the liquid sample to be tested is pumped into the liquid reservoir 6 through the liquid inlet 62. The amount of liquid taken each time is controlled by the different liquid level heights in the liquid reservoir 6 and the inner pore diameter of the pipetting capillary. The liquid sample to be tested enters the pipetting capillary through capillary phenomenon and liquid surface pressure, and rises to the highest point of the first upper bend 31. Then, under the action of gravity, the liquid sample moves to the first lower bend 32; due to the action of gravitational inertia, the liquid sample passes through the second upper bend 31 and is discharged from the liquid outlet 21, dripping into the dripping area 7.

[0066] When the distance between the liquid storage tank 6 and the dripping area 7 is relatively far, the intermediate tube 3 can be extended and a suction device 5 can be added to ensure that the liquid is pipetted to the designated location.

[0067] Obviously, the above-described embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention and are not intended to limit the manner in which the present invention is to be implemented. A person skilled in the art would be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A pipetting capillary tube, characterized in that include: A first straight tube (1), wherein the first straight tube (1) is arranged in a vertical direction, and the bottom end of the first straight tube (1) is a liquid intake port (11); a second straight tube (2), the second straight tube (2) and the first straight tube (1) being spaced apart and parallel to each other, the bottom end of the second straight tube (2) being a liquid outlet (21); An intermediate tube (3), the intermediate tube (3) comprising an upper curved tube (31) with an opening facing downward, the two ends of the upper curved tube (31) being respectively connected to the top end of the first straight tube (1) and the top end of the second straight tube (2) and being arranged in communication, so that under the action of capillary force, liquid can pass through the liquid intake port (11) and sequentially pass through the first straight tube (1), the intermediate tube (3) and the second straight tube (2) and be discharged from the liquid outlet (21); The first straight tube (1), the second straight tube (2) and the intermediate tube (3) are all capillaries.

2. The pipetting capillary according to claim 1, characterized in that The intermediate tube (3) comprises the upper curved tube (31) and the lower curved tube (32) with an opening facing upwards, the two ends of the lower curved tube (32) are respectively connected to the two upper curved tubes (31), and the ends of the two upper curved tubes (31) facing away from the lower curved tube (32) are respectively connected to the top end of the first straight tube (1) or the second straight tube (2).

3. The pipetting capillary according to claim 2, characterized in that The intermediate tube (3) comprises the upper curved tube (31), the lower curved tube (32) and a third straight tube (33). The third straight tube (33) is arranged between the first straight tube (1) and the second straight tube (2). The third straight tube (33) and the first straight tube (1) are arranged parallel to each other. The two ends of the third straight tube (33) are respectively connected to one of the upper curved tubes (31) and one of the lower curved tubes (32).

4. The pipetting capillary according to claim 3, characterized in that When the intermediate tube (3) includes more than two upper curved tubes (31), the top heights of the plurality of upper curved tubes (31) decrease in sequence along the direction from the first straight tube (1) to the first straight tube (1).

5. The pipetting capillary according to claim 2, characterized in that The axes of the upper curved tube (31) and the lower curved tube (32) are both semicircular arc shapes.

6. The pipetting capillary according to claim 1, characterized in that The pipetting capillary is an integrated structure capillary.

7. The pipetting capillary according to claim 1, characterized in that The pipetting capillary further comprises a cleaning device (4), and the cleaning device (4) is arranged on the intermediate tube (3).

8. The pipetting capillary according to claim 1, characterized in that The pipetting capillary further comprises a suction device (5), which is provided on the intermediate tube (3) and is configured to suck the liquid at the liquid extraction port (11) into the intermediate tube (3).

9. A capillary micro-sampling device, characterized in that: The invention comprises a liquid reservoir (6), a dripping area (7) and a pipetting capillary according to any one of claims 1 to 8, wherein the first straight tube (1) of the pipetting capillary extends from top to bottom into the liquid reservoir (6), the height of the liquid in the liquid reservoir (6) satisfies that the liquid can at least reach the highest point of the pipetting capillary under the action of capillary force, and the liquid outlet (21) of the second straight tube (2) of the pipetting capillary is arranged opposite to the dripping area (7).

10. The capillary micro-sampling device according to claim 9, characterized in that: The top of the liquid storage tank (6) is provided with a sampling port (61), and the side is provided with a liquid inlet (62); the first straight tube (1) passes through the sampling port (61) and is sealedly connected to the sampling port (61); the liquid inlet (62) is used to replenish the liquid in the liquid storage tank (6).

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