Electrolyte measuring structure, flow-type ion-selective electrode using the same, and electrolyte measuring device

Abstract

Provided is an electrolyte measurement structure that can reduce the influence of sample liquid stagnation on measurement values, perform accurate measurement, and smoothly perform replacement work of an ion-selective electrode. An electrolyte measurement structure has a main body (401) that can be connected to another electrolyte measurement structure via a sealing material and has a through flow path (401a), a fixing structure (404) having a fixing recess that fixes the sealing material (405) to the main body (401), and the sealing material (405), which is an elastic body integrally molded with a tab region and a protrusion region fixed to the fixing structure. In a state where the sealing material (405) is fixed to the fixing structure (404) and in a state where the sealing material (405) is not in contact with the other electrolyte measurement structure, the protrusion amount of a first portion where the surface of the tab region is most protruding is greater than the protrusion amount of a second portion where the surface of the protrusion region is most protruding.

Description

Technical Field

[0001] The present invention relates to an electrolyte measuring structure for determining the concentration of electrolytes in a solution, a flow-type ion-selective electrode having the electrolyte measuring structure, and an electrolyte measuring device. Background Technology

[0002] An ion-selective electrode is a device that quantifies the concentration of the target ion in a sample solution by measuring the electromotive force generated at the electrode of the detection unit when the sample solution comes into contact with the detection unit and the potential difference between the electrode and the reference electrode.

[0003] The flow-type ion-selective electrode in an ion-selective electrode has a built-in flow path for the flowing sample solution, and a detection unit is provided in the flow path. Therefore, by changing the sample solution flowing in the flow path, the concentration of the target ion can be continuously measured.

[0004] In addition, by connecting multiple flow-type ion-selective electrodes with different target ions, or by setting multiple detection units with different ions as target ions in the flow path within the electrode, it is possible to simultaneously measure the ion concentration of different ion types.

[0005] Based on these advantages, flow-type ion-selective electrodes are used in clinical examinations in the medical field, not only in dedicated electrolyte concentration measurement machines but also as electrolyte concentration measurement units in automated biochemical analysis devices. It should be noted that the ion-selective electrodes in electrolyte concentration measurement units are generally consumables with a lifespan of, for example, 2-3 months, and therefore need to be replaced with new ones after the specified period.

[0006] As a method for installing ion-selective electrodes into an electrolyte concentration measuring unit, as disclosed in Patent Document 1, it is known to stack multiple ion-selective electrodes and use O-rings at the connection points of each flow path.

[0007] Figure 15 This is a schematic diagram showing an example of a conventional structure of the flow path connection portion of the ion-selective electrode disclosed in Patent Document 1. The ion-selective electrode has a flow path 1502 that extends through a main body 1501 forming a housing, and a connection structure is formed in a convex shape at one end. This connection structure is constructed by holding an O-ring 1508, which is a sealing material, on a fixing structure having a recess 1510 for fixing the sealing material.

[0008] This connection structure can be fitted with the flow path connection portion 1507 disposed on other ion-selective electrodes 1591 to connect the flow paths of multiple ion-selective electrodes. Figure 15For convenience, the two connected flow paths are represented as a single unit. Since the flow path 1502 and the O-ring 1508 are positioned at a normal distance, a gap 1531 is created between the ion-selective electrodes. A portion of the sample solution flowing in the flow path 1502 flows into this gap 1531 and remains there. When multiple samples are measured sequentially, the retained sample solution is gradually released into the flow path as the sample solution for the next measurement flows.

[0009] In this configuration, the retained sample solution mixes with the sample solution intended for measurement, which can sometimes affect the measurement results. Specifically, the likelihood of affecting the results is low when the amount of sample solution is large, but it can affect the results and hinder accurate measurement when the amount of sample solution is small.

[0010] Furthermore, although the reagent consumption per sample in the electrolyte concentration measurement unit is minimal, continuous operation increases this consumption, requiring reagent bottles to be replaced several times a day. Reagent bottle replacements lead to a decrease in sample measurement throughput due to restarts; therefore, users strongly request that replacement frequency be reduced. It should be noted that reducing the reagent volume results in a higher percentage of residual liquid, thus having a greater impact on the measured values.

[0011] As a technology to solve such a problem, Patent Document 2 discloses the following technology: by using a sealing material with protrusions to reduce the gap between the flow path and the sealing material to suppress liquid residue, the protrusions are composed of a flat sheet portion and a convex portion fixed to a concave portion of an ion-selective electrode.

[0012] Figure 16 This is a schematic diagram showing an example of a conventional structure of the flow path connection portion of the ion-selective electrode disclosed in Patent Document 2. The ion-selective electrode has a flow path 1602 that extends through a main body 1601 forming a housing, and a connection structure is formed in a convex shape at one end thereof. This connection structure is constructed by holding the sealing material 1608 on a fixing structure having a recess 1610 for fixing the sealing material.

[0013] This connection structure can be fitted with the flow path connection portion 1607 disposed on other ion-selective electrodes 1691 to connect the flow paths of multiple ion-selective electrodes. Figure 16 For convenience, the two connected flow paths are represented as a single unit. Here, the sealing material 1608 is formed with a flat sheet for sealing and a protrusion for embedding into the recess 1610 for fixation. With such a structure, sealing the flow path by the sealing material 1608 allows the volume of the gap 1631 between the flow path and the sealing material to be very small, effectively reducing the amount of sample liquid retained in the flow path 1602.

[0014] Existing technical documents

[0015] Patent documents

[0016] Patent Document 1: Japanese Patent Application Publication No. 62-86548

[0017] Patent Document 2: International Publication No. 2015 / 115303 Summary of the Invention

[0018] The problem that the invention aims to solve

[0019] However, as described above, such ion-selective electrodes need to be replaced with new ones after each specified period. In this configuration, it is known that when the ion-selective electrodes are separated during electrode replacement, the sealing material 1608 sometimes adheres to the side of the ion-selective electrode 1691 and falls off.

[0020] The reason is believed to be that the contact area between the sealing material 1608 and the ion-selective electrode housing 1691 at the connection destination increases, and the adhesion between the sealing material and the ion-selective electrode housing at the connection destination increases during the approximately 2-3 month period of use. If such detachment occurs, the replacement operation becomes complicated.

[0021] Therefore, the inventors considered, in order to reliably hold the sealing material at the ion-selective electrode, that the width of the protrusion of the sealing material be larger than the width of the recess for fixing, thereby improving the fixing force in the fixing structure.

[0022] Figure 17 This illustrates an example of a flow path connection where the structure of the sealing material is altered to reliably hold the sealing material within the fixed ion-selective electrode. The ion-selective electrode has a flow path 1702 that extends through a main body 1701 forming the housing, and a connecting structure is formed in a convex shape at one end. This connecting structure holds the sealing material 1708 within a fixing structure that has a recess 1710 for fixing the sealing material.

[0023] This connection structure can be fitted with the flow path connection portion 1707 disposed on other ion-selective electrodes 1791 to connect the flow paths of multiple ion-selective electrodes. Figure 17 For convenience, the two connected flow paths are represented as a single unit. Here, the sealing material 1708 is formed with a flat sheet for sealing and a protrusion for embedding into the recess 1710 for fixation. To reliably hold the sealing material 1708 on the fixed structure, relative to... Figure 16 The sealing material 1608 has a structure in which the width of the protrusion of the sealing material 1708 is greater than the width of the recess 1710.

[0024] However, in this case, when the protrusion of the sealing material 1708 is embedded into the recess 1710, the protrusion is crushed, thus creating a raised structure on the upper part (peripheral region of the sealing material) of the protrusion of the sealing material 1708. Therefore, the gap 1731 between the other ion-selective electrodes connected to the flow path and the sealing material increases, and the problem of liquid residue resolved in Patent Document 2 recurs, potentially affecting the measurement results.

[0025] Methods for solving problems

[0026] To address the aforementioned issues, an example of the present invention is an electrolyte measuring structure having a housing and a sealing material. The structure is characterized in that it can be connected to other electrolyte measuring structures via the sealing material. The housing has a main body with a through flow path and a fixing structure for fixing the sealing material to the main body. The fixing structure has a first protrusion with a first hole connected to the flow path and a second protrusion formed on the outer periphery of the first protrusion. A fixing recess is formed by the first and second protrusions for fixing the sealing material in a detachable manner. The sealing material is an elastomer, having a surface designed to contact the other electrolyte measuring structures and a back surface designed to contact the fixing structure. It is integrally formed from a sheet region and a protruding region. The sheet region is a sheet-like region, and the protruding region is provided on the outer peripheral side of the sheet region and is a protrusion held by the fixing recess. When the sealing material is fixed to the fixing structure, the sheet region has a second hole disposed at a position corresponding to the first hole. When the sealing material is fixed to the fixing structure and does not contact the other electrolyte measuring structures, the first protrusion amount, as defined below, is greater than the second protrusion amount. The first protrusion amount is the protrusion amount of the first part that protrudes most on the surface of the sheet region, and the second protrusion amount is the protrusion amount of the second part that protrudes most on the surface of the protruding region.

[0027] Furthermore, the flow-type ion-selective electrode and electrolyte measuring device, which is an example of the present invention, is characterized by including the above-described electrolyte measuring structure.

[0028] Invention Effects

[0029] According to an embodiment of the present invention, when the connected electrolyte measuring structures are separated from each other, adhesion between the sealing material and other electrolyte measuring structures can be reduced, preventing the sealing material from falling off during electrode replacement, and effectively reducing the gap of sample liquid retention during connection (measurement). Therefore, the influence of sample liquid retention on the measured value can be reduced, accurate measurements can be performed, and electrode replacement can be carried out smoothly. Attached Figure Description

[0030] Figure 1A A schematic diagram illustrating a structural example of an electrolyte assay.

[0031] Figure 1B for Figure 1A The diagram shows a cross-sectional view of the structure used for electrolyte determination.

[0032] Figure 2A A schematic diagram illustrating an example of the connection of a structure used for electrolyte determination.

[0033] Figure 2B A schematic diagram illustrating an example of the connection of a structure used for electrolyte determination.

[0034] Figure 3 A schematic diagram illustrating one configuration example of an ion-selective electrode.

[0035] Figure 4A A schematic diagram showing other structural examples for electrolyte determination.

[0036] Figure 4B for Figure 4A The diagram shows a cross-sectional view of the structure used for electrolyte determination.

[0037] Figure 4C To be Figure 4A An enlarged view of the flow path connection of the structure for electrolyte measurement.

[0038] Figure 4D To be Figure 4A A cross-sectional view of the sealing component when it is removed from the electrolyte measurement structure.

[0039] Figure 5 This is an enlarged view of the flow path connection of the structure used for measuring other electrolytes.

[0040] Figure 6 This is a cross-sectional view of the structure used for electrolyte measurement when other sealing components are removed.

[0041] Figure 7 A cross-sectional view showing the removal of other sealing components from the electrolyte measurement structure.

[0042] Figure 8 A graph showing the results of simulation-based calculations of liquid residue.

[0043] Figure 9 A graph showing the results of a measurement of the holding force and adhesion force of a sealing material.

[0044] Figure 10 This is a figure showing the result of a surface roughness measurement with the sealing material installed on the ion-selective electrode housing.

[0045] Figure 11 A graph showing the result of an experiment confirming the deviation in electrolyte concentration measurement.

[0046] Figure 12 This is a schematic diagram illustrating one configuration example of an electrolyte measuring apparatus.

[0047] Figure 13A A schematic diagram illustrating a modified example of the flow path connection.

[0048] Figure 13B A schematic diagram illustrating a modified example of the flow path connection.

[0049] Figure 14 A schematic diagram illustrating a modified example of the flow path connection.

[0050] Figure 15 This is a schematic diagram showing an example of the flow path connection of a conventional ion-selective electrode.

[0051] Figure 16 This is a schematic diagram showing another example of the flow path connection of a conventional ion-selective electrode.

[0052] Figure 17 This is a schematic diagram showing a modified example of the flow path connection of a conventional ion-selective electrode. Detailed Implementation

[0053] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. It should be noted that the shaded lines in the drawings are for illustrative purposes only and do not necessarily represent cross-sections. Furthermore, in cross-sectional views, the shaded lines of the cross-section are sometimes omitted.

[0054] Figure 1A and Figure 1B This is a schematic diagram illustrating a structural example for electrolyte determination.

[0055] The electrolyte measuring structure 100 shown here is formed as a plastic body 101 having a through flow path 101a and a flow path connecting portion 102 connecting the flow path 101a to flow paths of other electrolyte measuring structures. Figure 1A This is a schematic diagram showing the surface (the surface on the side of the flow path connection 102) viewed from the axial direction of the flow path. Figure 1B It means Figure 1A A schematic diagram of the dashed line A-A' section (the plane parallel to the flow path).

[0056] The flow path connection portion 102 is provided in a convex shape at one end of the flow path 101a, and a concave flow path connection portion 103 is provided at the other end of the flow path 101a in a manner that fits into the flow path connection portion 102. Here, the flow path connection portion 102 is composed of a sealing material and a fixing structure for fixing the sealing material, and these structures will be described in detail later.

[0057] Because of this flow path connection, if a structure with the same structure for electrolyte measurement is prepared, these flow path connections can be connected. (See reference...) Figure 2A and Figure 2B The connection operation is explained. Figure 2A This diagram shows the state of the electrolyte measurement structure before connection. First, two electrolyte measurement structures 100 are prepared, and the flow path connection part 102 of one electrolyte measurement structure 100 is arranged opposite to the flow path connection part 103 of the other electrolyte measurement structure 100.

[0058] Then, bring these electrolyte assay structures 100 close to each other, such as... Figure 2B As shown, the flow path connection 102 and flow path connection 103 are engaged and pressed together. After this operation, the two electrolyte measuring structures 100 are fixed in a prescribed configuration, connecting their respective flow paths 101a. At this time, as described later, the flow path connection 102 and flow path connection 103 are connected via a sealing material, preventing the sample liquid from leaking to the outside when it flows from one flow path 101a to the other. It should be noted that the flow path connection 103 is used in the following... Figure 12 In the case of flow path connection structures 1256 and 1264, sometimes it is not necessary to set them.

[0059] in addition, Figure 3 It means that it was used. Figure 1A and Figure 1B A schematic diagram of one configuration example of an ion-selective electrode for electrolyte determination structure 100 is shown. Figure 3 Therefore with Figure 1B The corresponding cross-sectional view.

[0060] Such as Figure 3 As shown, the ion-selective electrode 300 has a sensing membrane 301, which serves as a detection unit, in contact with the flow path 101a. An internal liquid 302 is filled on the side opposite to the flow path 101a when viewed from the sensing membrane 301, and the electrode 303 is in contact with the internal liquid 302. The electrode 303 is, for example, made of a silver / silver chloride electrode.

[0061] When the sensing membrane 301 is a cation-selective electrode such as sodium or potassium, a cation-selective membrane, such as a crown ether membrane containing an ion carrier, can be used. When the sensing membrane 301 is an anion-selective electrode such as chloride or carbonic acid, in addition to membranes containing ion carriers, anion-selective membranes such as silver halides (e.g., silver chloride, silver bromide) or ion exchange membranes can also be used. Furthermore, when the sensing membrane 301 is used as a reference electrode, porous glass or ceramic materials can be used. While the sensing membrane 301 has been described above, known materials can be used as the membrane material, and it is not limited to these.

[0062] Next, the flow path connection section described above will be explained in detail below.

[0063] Figures 4A to 4D This is a schematic diagram illustrating the structure of an electrolyte measuring device, showing more specifically the structure of the flow path connection. Figure 4C and Figure 4D In particular, an example of the structure of the sealing material is shown.

[0064] Here, Figure 4A This is a schematic diagram showing the surface of the electrolyte measuring structure (the surface on the side of the flow path connection 402) as viewed from the axial direction of the flow path. Figure 4B It means Figure 4A A schematic diagram of the dashed-dot line section A-A' (the plane parallel to the flow path). Additionally, Figure 4C This is a schematic diagram showing the enlarged structure of the flow path connection part 402. Figure 4D It is a schematic diagram showing the cross-sectional shape of the sealing material when it is removed from the structure for electrolyte measurement.

[0065] The electrolyte measuring structure shown here has a plastic main body 401 with a through flow path 401a, a flow path connection portion 402 formed at one end of the flow path 401a, and a flow path connection portion 403 formed at the other end of the flow path 401a. Furthermore, the flow path connection portion 402 is composed of a fixing structure 404 and a sealing material 405. It should be noted that, in order to explain the fixing structure 404 provided on the main body 401, in… Figure 4B as well as Figure 4C For convenience, the boundary between the main body 401 and the fixed structure 404 is shown with a dashed line. However, the main body 401 and the fixed structure 404 can also be formed integrally or separately, and when they are combined, they are also referred to as the housing of the electrolyte measurement structure. In this case, a sealing material 405 is installed on the housing, which becomes the electrolyte measurement structure.

[0066] The main body 401 of the electrolyte determination structure has a through flow path 401a. This flow path 401a is the flow path through which the sample liquid for determination passes, and the main body 401 is formed as a through hole. In addition, the main body 401 may further have alignment protrusions other than the flow path connection portions 402 and 403.

[0067] A flow path connection part 402 is provided at one end of the flow path 401a to connect the flow path 401a to the flow path of other electrolyte measuring structures, and a flow path connection part 403 is further provided at the other end of the flow path 401a to connect the flow path of other electrolyte measuring structures.

[0068] For example, the flow path connection portion 402 is configured as a convex shape at one end of the flow path 401a, which is composed of a fixing structure 404 and a sealing material 405, and the flow path connection portion 403 is configured as a concave shape so that the flow path connection portion 402 fits into the other end of the flow path 401a.

[0069] Here, as Figure 4C As shown, the fixing structure 404 has a first protrusion 404a having a first hole 406 connected to the flow path 401a and a second protrusion 404b formed on the outer periphery of the first protrusion 404a. Furthermore, a fixing recess 404c for detachably fixing the sealing material 405 is formed through the first protrusion 404a and the second protrusion 404b. That is, the protruding portion of the sealing material 405 is clamped and fixed by the side of the first protrusion 404a and the side of the second protrusion 404b. It should be noted that all or part of the hole 406 is connected to the flow path 401a, as long as the sample liquid can pass through.

[0070] The sealing material 405 is formed from a soft material similar to that used in the electrolyte measurement structure, and is a component that can be detached from the housing (fixed structure 404). This sealing material 405 has a surface designed to contact other electrolyte measurement structures (on... Figure 4C , Figure 4D The diagram shows the upper side and the back side designed to contact the fixing structure 404 (first protrusion 404a). Figure 4C , Figure 4D The diagram shown is of the lower side.

[0071] That is, the surface of the sealing material 405 is the surface that contacts the other electrolyte measuring structures when the housing is connected to them. The back surface of the sealing material 405 is the surface that contacts the fixing structure of the electrolyte measuring structure. Therefore, when multiple electrolyte measuring structures are connected, the surface of the sealing material 405 contacts the other electrolyte measuring structures, and the back surface contacts the fixing structure 404 and is pressed, thereby preventing the sample liquid passing through the flow path 401a from leaking to the outside.

[0072] The sealing material 405 is integrally formed from a sheet-like region 405a and a protruding region 405b disposed on the outer peripheral side of the sheet-like region 405a and fixed by a recess 404c.

[0073] The plate region 405a is the portion covering the inner side (flow path 401a side) of the fixing recess 404c of the fixing structure 404. With the sealing material 405 fixed to the fixing structure 404, it has a second hole 407 positioned corresponding to the first hole 406. When the second hole 407 is fixed to the fixing structure 404 at its designated position, all or part of this hole is connected to the first hole 406, as long as the sample liquid can pass through.

[0074] The protruding region 405b is positioned corresponding to the fixing recess 404c of the fixing structure 404, and protrudes from the sheet region 405a on its outer peripheral side surface in a manner clamped by the fixing recess 404c. It should be noted that, preferably, the sealing material 405 is pressed and fixed in the fixing recess 404c as described above. In this case, it is sufficient to make the width of the protruding region 405b of the sealing material 405 larger than the width of the fixing recess 404c. Thus, the protruding region 405b is pressed and fixed by the sides of the first protrusion 404a and the sides of the second protrusion 404b, thereby maintaining a high fixing force.

[0075] When the sealing material 405 is fixed to the fixing structure 404 and is not in contact with other electrolyte measuring structures, the first protrusion amount, as defined below, is greater than the second protrusion amount. Here, the first protrusion amount is the protrusion amount of the first part when the most protruding part on the surface of the sheet region 405a is taken as the first part, and the second protrusion amount is the protrusion amount of the second part when the most protruding part on the surface of the protruding region 405b is taken as the second part.

[0076] These protrusions can also be described as protrusions in the direction of removal and assembly when removing and assembling multiple electrolyte measuring structures, for example, preferably protrusions along the central axis of the first hole 406 of the fixing structure 404.

[0077] More specifically, on the surface of the sealing material 405 that contacts other electrolyte measuring structures, a protruding surface of the fixing structure is formed. Figure 4CWhen the upper surface of the first protrusion 404a is used as the reference surface, the distance in the vertical direction from the reference surface is used as the protrusion amount. Furthermore, the portion of the surface with the largest protrusion amount in the sheet region 405a is designated as the first part, and the portion of the surface with the largest protrusion amount in the protrusion region 405b is designated as the second part. At this time, the sealing material is formed such that the protrusion amount of the first part is greater than that of the second part.

[0078] Figures 4A to 4D The sealing material 405 shown is an example where the first portion is adjacent to the second hole 407 of the sheet region 405a, and the second portion is the entire area of ​​the protruding region 405b (with the same amount of protrusion). In this case, the amount of protrusion of the first portion is greater than that of the second portion. When connected to other electrolyte measuring structures, the first portion is reliably sealed, and the second portion does not contact other electrolyte measuring structures, or even if it does, the pressure is weak.

[0079] Therefore, when the electrolyte measuring structures are separated from each other from the connected state, the surface of the sealing material in contact with the housing of other electrolyte measuring structures (especially the surface of the sheet region 405a) separates from the protruding region 405b side, which can suppress the adhesion of the sealing material 405 to other electrolyte measuring structures.

[0080] In the sheet region 405a of the sealing material 405, the aforementioned protrusion amount is such that the average thickness decreases from the second hole 407 side toward the outer periphery of the sheet region 405a, and the aforementioned protrusion amount and thickness are approximately the same. It should be noted that the average thickness in this specification refers to the average thickness in the circumferential direction formed with the second hole of the sealing material 405 as the center and at the same distance.

[0081] At this point, preferably, with the second hole 407 as a reference, the protrusion of the portion of the sheet region 405a farther from the first portion (the peripheral portion) is smaller than the protrusion of the first portion. This reduces the contact area with other electrolyte measuring structures, further suppressing adhesion. Furthermore, it is more preferable that the first portion is located adjacent to the second hole 407; in this case, the contact area with other electrolyte measuring structures can be further reduced, further suppressing adhesion.

[0082] It should be noted that, as Figure 4D As shown, an example is illustrated where the shape of the protruding region 405b (the upper part of the protruding region) located on the outer periphery of the sheet region 405a changes when the sealing material 405 is removed from the electrolyte measuring structure (fixed structure 404). In this specification, the portion whose shape changes (the portion where the shoulder falls off) is referred to as the "peripheral region" of the sealing material 405.

[0083] That is, in Figure 4DIn the peripheral region, within the surface of the sealing material, the average slope (proportion of change in protrusion) of the surface of the sheet region 405a is smaller than that of the surface of the protruding region 405b. That is, the slope of the protruding region 405b is greater than that of the sheet region 405a.

[0084] For example, in the sheet region 405a, when the contact surface with the first protrusion (the back surface of the sheet region 405a) when fixed to the fixing structure is set to a horizontal plane, this tilt can be expressed as an angle of tilt relative to the horizontal plane, preferably 2 to 10 degrees. In addition, the tilt angle of the protrusion region 405b relative to the horizontal plane is preferably 20 to 40 degrees.

[0085] Thus, in Figure 4D In this structure, the peripheral region of the protruding region 405b is lowered, but when fixing it to the electrolyte measuring structure (fixation structure 404), it is preferable to form it by pressing the protruding region 405b with the recess 404c. Therefore, it elastically deforms and bulges under this pressure, as... Figure 4C As shown, the amount of protrusion in protruding region 405b is approximately equal throughout the entire region of protruding region 405b. It should be noted that this is an example, and as explained above, as long as the amount of protrusion in the second part is maintained to be smaller than the amount of protrusion in the first part of plate region 405a, the amount of protrusion in protruding region 405b can vary in any way.

[0086] In addition, in this embodiment, the above-mentioned relationship of average inclination rate may not be satisfied, or either of them may be satisfied. However, if it is satisfied, it is possible to suppress the increase in the amount of protrusion of the surface of the protrusion region 405b (the peripheral region of the sealing material 405) when the sealing material 405 is installed, so it is preferred.

[0087] It should be noted that, in area 405a, it is preferable to start from the first part with the largest protrusion and extend to the connecting part of the protruding area, such as... Figure 4D As shown, its average thickness and average protrusion gradually decrease. At this time, when the electrolyte measuring structures are separated from each other, the separation force on the peripheral side of the sheet region 405a plays an effective role in the separation process. On the other hand, the thickness is thinner and the protrusion is smaller closer to the outer periphery, so separation occurs earlier, further reducing the risk of being carried away by other electrolyte measuring structures.

[0088] Furthermore, in Figure 4C In the middle, the structure becomes a close fit between the piece 312 and the first protrusion 309, but it does not necessarily need to be close fit, such as Figure 5As shown, when the protruding region 405b is fixed to the fixing recess 404c, even if the sheet region 405a is deformed and a space is formed between it and the first protrusion 404a, as long as it is in contact with the part near the flow path 401a, the retention of the sample liquid through the flow path 401a can be effectively suppressed.

[0089] As for the sealing material 405, its average thickness can be adjusted according to the structure used for measuring the electrolyte, and there is no particular limitation. For example, the following cases can be cited: the thickness of the connection between the sheet region 405a and the protruding region 405b is 0.1 to 0.5 mm, the thickness of the part of the sheet region 405a adjacent to the second hole 407 is 0.2 to 0.6 mm (wherein, it is 0.05 mm or more thicker than the thickness of the connection between the sheet region 405a and the protruding region 405b), and the width of the recess for embedding and fixing in the protruding region 405b is 1.0 to 1.2 mm.

[0090] More specifically, the following example illustrates a situation where the thickness of the connection portion (boundary) between the sheet region 405a and the protruding region 405b is 0.4 mm, and the thickness of the portion of the sheet region 405a adjacent to the second hole 407 is 0.5 mm. In this case, in the peripheral region of the protruding region 405b, it is preferable to have a structure formed by removing the shoulder so that its surface does not protrude more than the surface of the sheet region 405a.

[0091] It should be noted that, in Figures 4A to 4D The shapes shown are as follows: the fixed structure 404 is a cylindrical protrusion, and the sealing material 405 is integrally formed into an annular protrusion on the outer peripheral side of the disc-shaped sheet area; however, these shapes are not limited to these. However, from the perspective of sealing performance, ease of manufacture, and operation, the sealing material 405 is preferably formed in the following ways: Figures 4A to 4D The circle shown is used as the basic shape.

[0092] In addition, as other structures, such as Figure 6 As shown, it can also be illustrated that, in the state where the sealing material 405 is removed from the electrolyte measuring structure, the surface of the sealing material 405 is flat and has no slope in the sheet region 405a, while the back surface of the sealing material 405 has a slope. Figure 6 The figure shows the average thickness of region 405a and... Figure 4D Similarly, the sealing material 405 shown also varies, with the back side of the sealing material 405 forming a structure where the sheet region 405a protrudes further towards the fixing structure 404 as it gets closer to the second hole 407. In this... Figure 6 When the sealing material 405 is installed in the housing, its structure is similar to... Figure 4C The electrolyte assay shown has the same structure.

[0093] Furthermore, as described above, the sealing material 405 is made of an elastomer and is formed of a material that is softer than the shell of the electrolyte measuring structure. However, if the sealing material 405 is too soft, the protruding region 405b is not easily fixed by the fixing recess 404c; if it is too hard, the protruding region 405b will not enter the fixing recess 404c. Therefore, as the material of the sealing material 405, a rubber hardness of 60 to 80 is preferred.

[0094] It should be noted that, in the case where the sealing material 405 is formed from an elastomer, in reality, as... Figure 7 As shown, from a manufacturing point of view, it is preferable that its surface is formed with a smooth curvature. It should be noted that, in the case of such a curvature, it is preferable to include the entire area through which the sample liquid passes, and the portion extending axially along the second hole is regarded as the second hole 407. That is, when the inner surface of the second hole 407 of the sealing member is shaped to protrude towards the center of the second hole, this protruding portion is also included and thus constitutes the second hole.

[0095] At this time, since the first part is positioned adjacent to the second hole, the first part that is separated last becomes the smallest and is located at the very center of the sealing material 405. Therefore, while reducing the amount of retained sample liquid and disconnecting the connection of multiple electrolyte measurement structures, it is possible to more significantly suppress the sealing material from adhering to other electrolyte measurement structures.

[0096] In addition, Figure 7 In the middle, the sheet region 405a and the protruding region 405b are bounded by the part that becomes the starting point for forming the protruding region 405b (on the back of the sheet component, the starting point with curvature and variation in preparation for forming the protruding region from the flat surface of the sheet region).

[0097] By adopting the configuration described above, it is possible to reduce the amount of retained sample liquid while preventing the sealing material from being carried away by other electrolyte measuring structures when the connection between multiple electrolyte measuring structures is broken. It should be noted that this carry-away phenomenon is considered to occur, for example, due to the adhesive force of the sealing material, the adhesive force generated by the drying of the sample liquid, or the sample liquid acting as a sealant between the sealing material and other electrolyte measuring structures, acting like a suction cup when the connection is broken. In particular, it is believed that the adhesive force of the sealing material is initially weak due to secondary bonding (physical interactions such as hydrogen bonds and van der Waals forces) resulting from the diffusion and adsorption of the polymer constituting the sealing material at the bonding interface during the initial contact between the sealing material and the electrolyte measuring structure. However, over time, a primary bonding (chemical interaction) develops, thereby developing into a stronger adhesion.

[0098] In this embodiment, to mitigate the phenomenon of being carried away, when disengaging, the protruding area with a small amount of protrusion is first firmly fixed by the recess, thereby increasing the distance between it and other electrolyte measuring structures (due to continuous elastic deformation of the sealing material) before separation. Then, the sheet area gradually separates. Therefore, compared to the prior art patent document 2 where the entire surface of the sealing material separates at once, less force is applied. Furthermore, since separation begins from the outside, allowing external air to enter, the effect of a suction cup is also reduced.

[0099] like Figure 3 As shown, the structure for electrolyte determination described above can form an ion-selective electrode by setting up a sensing membrane, an internal liquid, and an electrode.

[0100] Figure 8 Indicates for Figure 16 The conventional structure of the flow path connection shown is... Figure 4C The structure of the flow path connection portion shown in this embodiment is obtained by calculating the proportion of liquid residue, i.e., the ratio of the gap portion volume to the flow path portion volume, through large deformation analysis based on the finite element method.

[0101] The sealing material was modeled using a nonlinear Neo-Hoken model (Beomkeun Kim et al.: International Journal of Precision Engineering and Manufacturing, 13, pp. 759-764 (2012)), with initial shear modulus set at 3.3 MPa and Poisson's ratio at 0.4999. Since it is a body of revolution, a two-dimensional shaft object model was used for calculations. Analysis was performed using ANSYS Workbench 19.2 (ANSYS).

[0102] In the conventional structure of the flow path connection, the proportion of liquid residue is about 0.9%. In contrast, in the structure of the flow path connection in this embodiment, the proportion of liquid residue can be reduced to about 0.5%.

[0103] Figure 9 Indicates for Figure 16 The conventional structure of the flow path connection shown is... Figure 4C The structure of the flow path connection portion of this embodiment is shown, along with the measurement results of the retaining force and adhesion force of the sealing material.

[0104] The holding force of the sealing material is determined as follows: After embedding the sealing material into the recess of the housing or the fixing recess, apply a fast-curing adhesive to the surface of the sealing material, attach it to the clamp connected to the tensile testing machine, and measure the maximum load that causes the clamp to rise until the sealing material is detached.

[0105] The adhesive force of the sealing material is determined as follows: using the same material as the sealing material, a sheet sample of the same area, and a plate of the same material as the shell, the sample and the plate are brought into contact under pressure for a certain period of time. A fast-curing adhesive is then applied to the upper surface of the sample, which is then attached to a clamp connected to a tensile testing machine. The maximum load that causes the clamp to rise until the sample is detached is measured.

[0106] Figure 9 The vertical axis represents the difference between the holding force and the adhesion force; if the holding force is greater than the adhesion force, it becomes a positive value. Compared to the conventional structure of the flow path connection, in the structure of the flow path connection in this embodiment, the holding force is significantly greater than the adhesion force. This means that the sealing material can be prevented from falling off when replacing the electrode, and the replacement operation can be kept simple.

[0107] Figure 10 Indicates for Figure 16 The conventional structure of the flow path connection shown is... Figure 4C The structure of the flow path connection portion shown in this embodiment is based on the measurement results of the surface irregularity shape with the sealing material installed in the ion-selective electrode housing.

[0108] Figure 10 The center of the horizontal axis (0 point) represents the center of the flow path. In conventional structures, the peripheral portion is a protruding shape, but in the structure of this embodiment, it is known that the protrusion is most prominent near the center of the flow path. With this structure, when the ion-selective electrode is connected to the electrolyte measuring structure, the sealing material begins to contact from near the flow path, thus reliably sealing the area near the flow path. In the portion connected to the flow path, the volume of the gap between the other electrolyte measuring structure and the sealing material can be reduced, thereby effectively reducing the amount of sample liquid retained in the flow path.

[0109] Figure 12 This is a schematic diagram showing an example of an electrolyte measuring apparatus using the structure of Figure 1 for electrolyte measurement.

[0110] The measuring unit 1251 is connected to the recording and calculation unit 1271, the control unit 1272, and the display unit 1273. The measuring unit 1251 includes a dilution tank 1270, ion-selective electrodes 1261, 1262, and 1263, a reference electrode 1255, flow path connection structures 1254, 1256, 1260, and 1264, a potential measuring unit 1265, piping 1252, 1257, and 1266, a pump 1258, dispensing nozzles 1267, 1268, and 1269, a reference solution 1253, and a waste liquid tank 1259.

[0111] Here, the structure for electrolyte determination is ion-selective electrodes 1261, 1262, 1263, a reference electrode 1255, and flow path connection structures 1254, 1256, 1260, 1264.

[0112] Blood, urine, and other samples, diluent, and internal standard solution are dispensed into and discharged from dilution tank 1270 through dispensing nozzles. Pump 1266 is used to evacuate the solution from dilution tank 1270.

[0113] The solution drawn from the dilution tank 1270 is introduced through piping 1266 into the flow path of ion-selective electrodes 1263, 1262, and 1261, and further disposed of in waste tank 1259 via piping 1257 and pump 1258. Conversely, the reference solution 1253 is introduced through piping 1252 into the flow path of reference electrode 1255, and further disposed of in waste tank 1259 via piping 1257 and pump 1258. The terminals of the electrodes are connected to the potential measurement unit 1265.

[0114] Figure 11 Indicates use Figure 12 The electrolyte measuring device shown is for Figure 15 The conventional structure of the flow path connection shown (conventional structure 1) Figure 16 The conventional structure (conventional structure 2) of the flow path connection shown and Figure 4C The results of the electrolyte concentration measurement deviation confirmation experiment were conducted on the structure of the flow path connection part shown in this embodiment.

[0115] In the experiment, the deviation of the measured values ​​when the concentration of concentrated potassium solution (80 mmol / L or 100 mmol / L) was evaluated. Since the concentration measurement reflects individual differences in the electrodes used, and different electrodes had to be used in the evaluation of the structure in this embodiment compared to the measurements of conventional structure 2, the electrode housing was set to be shared in each measurement. The deviation of the measured potassium concentration when the sealing material of conventional structure 1 was used as the sealing material was evaluated, and the ratio of the deviation of the measured potassium concentration when the sealing material of this structure was used to this value was set as the standardized deviation.

[0116] The standardized deviation in the structure of this embodiment is about 0.6, which is a reduction compared to the standardized deviation of about 0.8 in the conventional structure 2.

[0117] <Variation Example>

[0118] Figure 13A and Figure 13B This is a schematic diagram showing other configuration examples of the flow path connection portion of the structure for electrolyte measurement according to the present invention.

[0119] Figure 13AThis is a schematic diagram showing the flow path connection with the sealing material installed on the electrolyte measuring structure. The structure not depicted in this diagram is similar to the structure described above. Figures 4A to 4C )same.

[0120] In this structure, the average thickness of the sheet region 405a adjacent to the second hole 407 is greater than the average thickness of the connection portion between the sheet region 405a and the protruding region 405b. Furthermore, in this… Figure 13A In the plate region 405a, the first portion is formed to have a width extending outward from the second hole, and the thickness of the first portion increases in that region. Therefore, when separating multiple electrolyte measurement structures, by increasing the thickness of the last separated first portion, the elastomeric restoring force of the sealing material from the start to the end of separation can assist in the separation of the portion other than the first portion.

[0121] In addition, such as Figure 13B As shown, the surface of the sheet region 405a may also have an uneven structure 1301. However, the depth of this uneven structure is shallower than the difference between the average thickness of the sheet region 405a at the location adjacent to the second hole 407 and the average thickness of the connection portion of the sheet region 405a with the protruding region 405b.

[0122] With this structure, when connecting the electrolyte measuring structure, the sealing material begins to contact near the flow path, thus sealing the area near the flow path. Since the volume of the gap between the other electrolyte measuring structures connected to the flow path and the sealing material can be reduced, the amount of sample liquid retained in the flow path can be effectively reduced.

[0123] Figure 14 This is a schematic diagram showing another structural example of the flow path connection of the present invention relating to the structure for electrolyte measurement. An enlarged view shows the flow path connection with the sealing material installed in the electrolyte measurement structure. The structure not depicted in this figure is similar to the structure described above. Figures 4A to 4C )same.

[0124] In this structure, an example is shown where the average thickness decreases from the second hole 407 in the sheet region 405a toward the outer periphery, and the average thickness increases toward the reversed outer periphery in the middle.

[0125] Even under such circumstances, if the protrusion of the first portion in the sheet region 405a is greater than the protrusion of the second portion in the protruding region 405b, the sealing material 405 will initially contact the flow path when connected to the electrolyte measuring structure, thus sealing the flow path area. In this example, the same effect as described in this embodiment can be achieved, reducing the volume of the gap between the other electrolyte measuring structure connected to the flow path and the sealing material, thereby effectively reducing the amount of sample liquid retained in the flow path.

[0126] As can be seen from the above, the electrolyte measurement structure can be used to construct an ion-selective electrode. In addition, when multiple electrolyte measurement structures are connected to form an electrolyte measurement device, it is possible to achieve two beneficial effects: suppressing the shedding of sealing material when replacing the electrolyte measurement structure and reducing the amount of sample liquid retained in the gap of the flow path connection, thereby reducing the impact on the measurement results.

[0127] It should be noted that the present invention is not limited to the above-described embodiments, and includes various modifications. The above embodiments are described in detail for the purpose of easily understanding the present invention, and are not necessarily limited to having all the described configurations. It is possible to add, delete, or substitute configurations of other embodiments to the configuration of one embodiment.

[0128] Symbol Explanation

[0129] 100: Structure for electrolyte determination,

[0130] 101, 401: Main body,

[0131] 101a, 401a: flow path,

[0132] 102, 402: Flow path connection part,

[0133] 103, 403: Flow path connection part,

[0134] 300: Ion-selective electrode.

[0135] 301: Sensing film,

[0136] 302: Internal fluid,

[0137] 303: Electrode,

[0138] 404: Fixed structure,

[0139] 404a: First protrusion,

[0140] 404b: Second protrusion,

[0141] 404c: Fixing recess,

[0142] 405: Sealing material,

[0143] 405a: Area,

[0144] 405b: Protruding area,

[0145] 406: First hole,

[0146] 407: Second hole,

[0147] 1251: Measurement unit,

[0148] 1252, 1257, 1266: piping,

[0149] 1253: Reference solution

[0150] 1254, 1256, 1260, 1264: Flow path connection structure.

[0151] 1255: Reference electrode

[0152] 1258: Pump

[0153] 1259: Waste liquid tank,

[0154] 1261, 1262, 1263: Ion-selective electrodes

[0155] 1265: Potential Measurement Unit

[0156] 1267, 1268, 1269: Dispensing nozzles,

[0157] 1270: Dilution tank

[0158] 1271: Recording and Calculation Department,

[0159] 1272: Control Department

[0160] 1273: Display section.

Claims

1. A structure for electrolyte determination, characterized in that, It has a housing and sealing material. The structure for electrolyte measurement can be connected to other structures for electrolyte measurement via the sealing material. The housing has a main body with a through flow path and a fixing structure for fixing the sealing material to the main body. The fixing structure has a first protrusion having a first hole connected to the flow path and a second protrusion formed on the outer periphery of the first protrusion. Furthermore, a fixing recess is formed by the first and second protrusions for fixing the sealing material in a detachable manner. The sealing material is an elastomer, having a surface designed to contact the other electrolyte measuring structures and a back surface designed to contact the fixing structure. It is integrally formed from a sheet region and a protruding region. The sheet region is a sheet-like area, and the protruding region is located on the outer peripheral side of the sheet region and is a protrusion held by the fixing recess. With the sealing material fixed to the fixing structure, the sheet region has a second hole positioned corresponding to the first hole, and all or part of the second hole is connected to the first hole to allow the sample liquid to pass through. When the sealing material is fixed to the fixed structure and does not contact the other electrolyte measuring structures, the first protrusion amount, as defined below, is larger than the second protrusion amount. The first protrusion amount is the protrusion amount of the first most prominent part on the surface of the sheet area, and the second protrusion amount is the protrusion amount of the second most prominent part on the surface of the protrusion area. The first protrusion amount and the second protrusion amount are the protrusion amounts along the central axis of the first hole when the surface of the first protrusion to contact the back of the sealing material is taken as the reference surface. The first part is the part adjacent to the second hole. When the sealing material is removed from the fixing structure, in the sheet area, from the first part to the protruding area, the average thickness and average protrusion gradually decrease.

2. The structure for electrolyte determination according to claim 1, characterized in that, The protruding area of ​​the sealing material is clamped by the sides of the first and second protrusions forming the fixing recess and is pressed and fixed.

3. The structure for electrolyte determination according to claim 1, wherein, Based on the second hole, the amount of protrusion of the portion of the plate region that is farther from the first portion is smaller than the amount of protrusion of the first portion.

4. The structure for electrolyte determination according to claim 1, wherein, The inner surface of the sealing material forming the second hole protrudes toward the center of the second hole.

5. The structure for electrolyte determination according to claim 1, characterized in that, The thickness of the first portion is greater than the average thickness of the connection portion between the sheet region and the protruding region.

6. The structure for electrolyte determination according to claim 1, characterized in that, With the sealing material detached from the fixing structure, when viewed in cross-section through the central axis of the second hole, the first inclination rate, as defined below, is less than the second inclination rate. The first slope is the average slope of the surface of the sheet region, and the second slope is the average slope of the surface of the protruding region.

7. A flow-type ion-selective electrode comprising the structure for electrolyte determination according to any one of claims 1 to 6.

8. An electrolyte measuring device comprising the electrolyte measuring structure according to any one of claims 1 to 6.

Images