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

Abstract

To provide an electrolyte measuring structure capable of reducing influence on a measurement value due to retention of sample liquid, performing accurate measurement, and smoothly performing replacement work for ion selective electrodes.SOLUTION: An electrolyte measuring structure can be connected to another electrolyte measuring structure through a sealing material, and has a body 401 having a flow path 401a penetrating therethrough, a fixing structure 404 having a fixing recess for fixing a sealing material 405 to the body 401, and the sealing material 405. The sealing material 405 is an elastic body in which a sheet region and a protrusion region fixed to the fixing structure are integrally molded. With the sealing material 405 fixed to the fixing structure 404 and not in contact with the other electrolyte measuring structure, an amount of protrusion at a first point which is the most protruding point on the surface of the sheet area is larger than an amount of protrusion at a second point which is the most protruding point on the surface of the protrusion area.SELECTED DRAWING: Figure 4B

Description

[Technical field]

[0001] The present invention relates to an electrolyte measurement structure for measuring an electrolyte concentration in a solution, a flow-type ion selective electrode including the electrolyte measurement structure, and an electrolyte measurement device. [Background technology]

[0002] An ion selective electrode is a device that can quantify the concentration of a target ion in a sample liquid by measuring the potential difference between the electromotive force generated in the detection section electrode when the sample liquid is brought into contact with the detection section and a reference electrode.

[0003] Among ion-selective electrodes, the flow-type ion-selective electrode has a built-in flow path through which the sample liquid flows, and a detection unit is provided in the flow path. Therefore, by changing the sample liquid flowing in the flow path, it is possible to continuously measure the concentration of the target ion.

[0004] In addition, by connecting multiple flow-type ion-selective electrodes each having different target ions to be measured, or by providing multiple detection sections in the flow path within the electrode that target different ions to be measured, it is possible to simultaneously measure the ion concentrations of different ion species.

[0005] Due to these advantages, flow-type ion-selective electrodes are used in clinical testing in the medical field, and are installed as electrolyte concentration measurement units not only in dedicated devices for electrolyte concentration measurement, but also in automatic biochemical analyzers. Note that ion-selective electrodes in electrolyte concentration measurement units are generally consumables, and have a lifespan of, for example, two or three months, so they must be replaced with new ones every time a specified period of time has passed.

[0006] A well-known method for attaching an ion selective electrode to an electrolyte concentration measurement unit is to stack multiple ion selective electrodes and use O-rings at the connection points of each flow path, as disclosed in Patent Document 1.

[0007] 15 is a schematic diagram showing an example of a conventional structure of a flow channel connection part of an ion selective electrode disclosed in Patent Document 1. This ion selective electrode has a flow channel 1502 penetrating a main body 1501 forming a housing, and a connection structure is formed in a convex shape at one end of the flow channel. This connection structure is configured by holding an O-ring 1508, which is a sealing material, in a fixing structure in which a recess 1510 for fixing a sealing material is formed.

[0008] This connection structure can be fitted with a flow channel connector 1507 provided on another ion selective electrode 1591 to connect the flow channels of multiple ion selective electrodes. In FIG. 15, the two connected flow channels are shown as one for convenience. Since the flow channel 1502 and the O-ring 1508 are usually arranged at a certain distance from each other, a gap 1531 is generated between the ion selective electrodes. A part of the sample liquid flowing through the flow channel 1502 flows into this gap 1531 and accumulates there. When multiple specimens are measured in sequence, the accumulated sample liquid is gradually released into the flow channel when the sample liquid for the next measurement flows in.

[0009] In this type of structure, the retained sample liquid may mix with the sample liquid that is the intended measurement target, which may affect the measurement results. That is, if the amount of sample liquid is large, it is unlikely to affect the measurement results, but if the amount of sample liquid is small, it may affect the measurement results and prevent accurate measurement.

[0010] In addition, although the electrolyte concentration measurement unit consumes only a small amount of reagent per sample, the consumption increases during continuous operation, making it necessary to replace the reagent bottles several times a day. Replacing the reagent bottles leads to a decrease in the throughput of sample measurement due to restarting, so users strongly request a reduction in the number of replacement operations. Furthermore, reducing the amount of reagent liquid increases the proportion of residual liquid, which has a greater impact on the measured values.

[0011] To solve these problems, Patent Document 2 discloses a technology that uses a sealing material having protrusions consisting of a flat sheet portion and a convex portion that is fixed to the concave portion of the ion-selective electrode, thereby reducing the gap between the flow path and the sealing material and suppressing residual liquid.

[0012] 16 is a schematic diagram showing an example of a conventional structure of a flow channel connection part of an ion selective electrode disclosed in Patent Document 2. This ion selective electrode has a flow channel 1602 penetrating a main body 1601 forming a housing, and a connection structure is formed in a convex shape at one end of the flow channel. This connection structure is configured by holding a sealant 1608 in a fixing structure in which a recess 1610 for fixing the sealant is formed.

[0013] This connection structure can be fitted with a flow channel connection part 1607 provided on another ion selective electrode 1691 to connect the flow channels of a plurality of ion selective electrodes. In FIG. 16, the two connected flow channels are shown as one unit for convenience. Here, the sealant 1608 is formed with a flat sheet part for sealing and a protrusion that fits into the recess 1610 for fixing. With such a structure, the sealant 1608 seals up to the vicinity of the flow channel, and the volume of the gap 1631 between the flow channel and the sealant can be made very small, effectively reducing the amount of the sample liquid flowing through the flow channel 1602 that remains. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] Japanese Patent Application Publication No. 62-86548 [Patent Document 2] International Publication No. 2015 / 115303 Summary of the Invention [Problem to be solved by the invention]

[0015] However, such an ion selective electrode needs to be replaced with a new one every time a certain period of time elapses, as described above. With this structure, it was found that when the ion selective electrodes are separated from each other during electrode replacement, the sealant 1608 may stick to the ion selective electrode 1691 and fall off.

[0016] This is thought to be because the contact area between the sealant 1608 and the connected ion-selective electrode housing 1691 becomes large, and the sealant and the connected ion-selective electrode housing become more firmly attached during the two or three months of use. If this type of detachment occurs, the replacement work becomes complicated.

[0017] Therefore, the inventors came up with an idea to improve the fixing strength of the fixing structure by making the width of the protrusion of the sealing material larger than the width of the fixing recess in order to securely hold the sealing material on the ion selective electrode, in comparison with the technology of Patent Document 2.

[0018] 17 shows an example of a flow path connection part in which the structure of the sealant is changed so that the sealant is securely held by the ion selective electrode to which it is to be fixed. This ion selective electrode has a flow path 1702 penetrating a main body 1701 forming a housing, and a connecting structure is formed in a convex shape at one end of the flow path. This connecting structure is configured such that a sealant 1708 is held by a fixing structure in which a recess 1710 for fixing the sealant is formed.

[0019] This connection structure can be fitted with a flow path connection portion 1707 provided on another ion selective electrode 1791 to connect the flow paths of a plurality of ion selective electrodes. In FIG. 17, the two connected flow paths are shown as one unit for convenience. Here, the sealant 1708 is formed with a flat sheet portion for sealing and a protrusion that fits into a recess 1710 for fixing. In order to reliably hold the sealant 1708 in the fixed structure, the sealant 1708 has a structure in which the width of the protrusion of the sealant 1708 is made larger than the width of the recess 1710, as compared to the sealant 1608 in FIG. 16.

[0020] However, in this case, when the protrusion of the sealant 1708 is fitted into the recess 1710, the protrusion is crushed, resulting in a raised structure at the top of the protrusion of the sealant 1708 (the peripheral region of the sealant). As a result, the gap 1731 between the sealant and the other ion selective electrodes connected to the flow channel increases, and there is a concern that the problem of residual liquid, which was solved in Patent Document 2, will reoccur and affect the measurement results. [Means for solving the problem]

[0021] In order to solve the above problems, one example of an electrolyte measurement structure of the present invention is an electrolyte measurement structure having a housing and a sealing material, wherein the electrolyte measurement structure is connectable to another electrolyte measurement structure via the sealing material, the housing has a main body having a flow path therethrough, 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, and a fixing recess for removably fixing the sealing material is formed by the first protrusion and the second protrusion. The sealing material has a surface designed to contact the other electrolyte measurement structure and a back surface designed to contact the fixed structure, and is an elastic body in which a sheet area, which is a sheet-shaped area, and a protrusion area, which is a protrusion provided on the outer peripheral side of the sheet area and is sandwiched in the fixing recess, are integrally molded, and the sheet area has a second hole that is arranged at a position corresponding to the first hole when the sealing material is fixed to the fixed structure, and when the sealing material is fixed to the fixed structure and is not in contact with the other electrolyte measurement structure, a first protrusion amount defined as follows is greater than a second protrusion amount: the first protrusion amount is the protrusion amount of a first point that protrudes most on the surface of the sheet area, and the second protrusion amount is the protrusion amount of a second point that protrudes most on the surface of the protrusion area.

[0022] A flow-type ion selective electrode and an electrolyte measuring device according to an embodiment of the present invention include the above-mentioned structure for electrolyte measurement. Effect of the Invention

[0023] According to an embodiment of the present invention, when connecting electrolyte measurement structures to separate them, adhesion between the sealant and the other electrolyte measurement structures can be reduced to prevent the sealant from falling off during electrode replacement, while effectively reducing the gap in which sample liquid accumulates during connection (measurement). This reduces the effect of sample liquid accumulation on the measurement value, allowing accurate measurement and smooth electrode replacement. [Brief description of the drawings]

[0024] [Figure 1A] FIG. 2 is a schematic diagram showing a configuration example of an electrolyte measurement structure. [Figure 1B] FIG. 1B is a cross-sectional view of the electrolyte measurement structure shown in FIG. 1A. [Figure 2A] FIG. 4 is a schematic diagram illustrating an example of a connection of the electrolyte measurement structure. [Figure 2B] FIG. 4 is a schematic diagram illustrating an example of a connection of the electrolyte measurement structure. [Diagram 3] FIG. 1 is a schematic diagram showing an example of the configuration of an ion selective electrode. [Figure 4A] FIG. 13 is a schematic diagram showing another configuration example of the electrolyte measurement structure. [Figure 4B] FIG. 4B is a cross-sectional view of the electrolyte measurement structure shown in FIG. 4A. [Figure 4C] FIG. 4B is an enlarged view of the flow path connection portion of the electrolyte measurement structure shown in FIG. 4A. [Figure 4D] 4B is a cross-sectional view of the sealing member of FIG. 4A when removed from the electrolyte measurement structure. FIG. [Diagram 5] FIG. 13 is an enlarged view of a flow path connection portion of another electrolyte measurement structure. [Figure 6] 13 is a cross-sectional view of the electrolyte measurement structure with another sealing member removed therefrom. FIG. [Figure 7] 13 is a cross-sectional view of the electrolyte measurement structure with still another sealing member removed therefrom. FIG. [Figure 8] FIG. 11 is a diagram showing the results of calculation of the remaining liquid amount by simulation. [Figure 9] FIG. 13 is a diagram showing a result of measurement of the holding strength and adhesion strength of a sealing material. [Figure 10]FIG. 13 is a diagram showing a result of measuring the surface irregularity shape in a state where a sealing material is attached to an ion selective electrode housing. [Figure 11] FIG. 13 is a diagram showing a result of an experiment to confirm deviation in electrolyte concentration measurement. [Figure 12] FIG. 1 is a schematic diagram showing an example of the configuration of an electrolyte measuring device. [Figure 13A] 13A and 13B are schematic diagrams illustrating modified examples of the flow path connection portion. [Figure 13B] 13A and 13B are schematic diagrams illustrating modified examples of the flow path connection portion. [Figure 14] 13A and 13B are schematic diagrams illustrating modified examples of the flow path connection portion. [Figure 15] FIG. 1 is a schematic diagram showing an example of a flow channel connection part of a conventional ion selective electrode. [Figure 16] FIG. 13 is a schematic diagram showing another example of a flow channel connection portion of a conventional ion selective electrode. [Figure 17] FIG. 13 is a schematic diagram showing a modified example of a flow channel connection part of a conventional ion selective electrode. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that hatching in the drawings is provided for the purpose of explanation and does not necessarily represent a cross section. In addition, even in cross-sectional views, hatching of the cross section may be omitted.

[0026] 1A and 1B are schematic diagrams for explaining one configuration example of a structure for electrolyte measurement. The electrolyte measurement structure 100 shown here is formed with a plastic body 101 having a flow path 101a penetrating therethrough, and a flow path connecting part 102 that connects the flow path 101a to a flow path of another electrolyte measurement structure. Here, Fig. 1A is a schematic diagram showing a surface viewed from the axial direction of the flow path (the surface on the flow path connecting part 102 side), and Fig. 1B is a schematic diagram showing a dashed line A-A' cross section (a surface parallel to the flow path) of Fig. 1A.

[0027] The flow path connecting part 102 is provided, for example, in a convex shape at one end of the flow path 101a, and a concave flow path connecting part 103 is provided at the other end of the flow path 101a so as to fit into the flow path connecting part 102. Here, the flow path connecting part 102 is composed of a sealant and a fixing structure for fixing the sealant, and these structures will be described in detail later.

[0028] Since the electrolyte measurement structure has such a flow path connection portion, when electrolyte measurement structures of the same structure are prepared, their flow path connection portions can be connected. The connection operation will be described with reference to Fig. 2A and Fig. 2B. Fig. 2A is a diagram showing the state before the electrolyte measurement structures are connected. First, two electrolyte measurement structures 100 are prepared, and the flow path connection portion 102 of one electrolyte measurement structure 100 is arranged opposite to the flow path connection portion 103 of the other electrolyte measurement structure 100.

[0029] Then, these electrolyte measurement structures 100 are brought close to each other, and as shown in FIG. 2B, the flow path connection part 102 is fitted into the flow path connection part 103 and pressed against each other. Then, the two electrolyte measurement structures 100 are fixed in a predetermined arrangement, and the respective flow paths 101a are connected. At this time, as described later, the flow path connection part 102 and the flow path connection part 103 are connected via a seal material, and when the sample liquid for measurement flows from one flow path 101a to the other flow path 101a, the sample liquid can be prevented from leaking to the outside. Note that the flow path connection part 103 may not be provided when used in flow path connection structures 1256 and 1264 in FIG. 12 described later.

[0030] Moreover, Fig. 3 is a schematic diagram showing one configuration example of an ion selective electrode using the electrolyte measurement structure 100 shown in Fig. 1A and Fig. 1B. Fig. 3 is a cross-sectional view corresponding to Fig. 1B.

[0031] 3, in the ion selective electrode 300, a sensitive membrane 301 serving as a detection unit is in contact with the flow path 101a. An internal liquid 302 is filled on the opposite side of the sensitive membrane 301 from the flow path 101a, and an electrode 303 is in contact with the internal liquid 302. The electrode 303 is made of, for example, a silver / silver chloride electrode.

[0032] When the sensitive membrane 301 is used as a cation selective electrode for sodium, potassium, etc., a membrane having selective permeability for cations, such as a membrane containing an ionophore such as crown ether, can be used. When the sensitive membrane 301 is used as an anion selective electrode for chloride, carbonate, etc., a membrane having selective permeability for anions, such as a silver halide such as silver chloride or silver bromide or an ion exchange membrane, in addition to a membrane containing an ionophore, can be used. When the sensitive membrane 301 is used as a reference electrode, porous glass, ceramics, etc. can be used. Although the sensitive membrane 301 has been described above, the material of the membrane can be any known material and is not limited to these.

[0033] Next, the above-described flow path connection portion will be described in detail below. 4A to 4D are schematic diagrams for explaining an electrolyte measurement structure showing the configuration of a flow path connection part in more detail, and in particular, FIG. 4C and FIG. 4D show an example of the configuration of a sealing material in detail.

[0034] Here, Fig. 4A is a schematic diagram showing the surface of the electrolyte measurement structure as viewed from the axial direction of the flow channel (the surface on the side of flow channel connection part 402), and Fig. 4B is a schematic diagram showing the dashed line A-A' cross section (a surface parallel to the flow channel) in Fig. 4A. Fig. 4C is a schematic diagram showing an enlarged view of the structure of flow channel connection part 402, and Fig. 4D is a schematic diagram showing the cross-sectional shape of the sealant when the sealant is removed from the electrolyte measurement structure.

[0035] The electrolyte measurement structure shown here has a plastic body 401 having a through flow path 401a, a flow path connection part 402 formed at one end of the flow path 401a, and a flow path connection part 403 formed at the other end of the flow path 401a. The flow path connection part 402 is composed of a fixing structure 404 and a seal material 405. In order to explain the fixing structure 404 provided on the body 401, the boundary between the body 401 and the fixing structure 404 is shown by a dashed line in Fig. 4B and Fig. 4C for the sake of convenience, but the body 401 and the fixing structure 404 may be formed either integrally or separately, and these are collectively referred to as the housing of the electrolyte measurement structure. In this case, the seal material 405 is attached to the housing to form the electrolyte measurement structure.

[0036] The main body 401 of this electrolyte measurement structure has a flow path 401a penetrating therethrough. This flow path 401a is a flow path for passing a sample liquid for measurement, and is formed as a through hole in the main body 401. Furthermore, the main body 401 may further have a protrusion for alignment other than the flow path connecting parts 402 and 403.

[0037] A flow path connection part 402 is provided at one end of the flow path 401a, which connects the flow path 401a to a flow path of another electrolyte measurement structure, and a flow path connection part 403 is provided at the other end of the flow path 401a, which connects the flow path to a flow path of yet another electrolyte measurement structure.

[0038] The flow path connection portion 402 is provided, for example, at one end of the flow path 401a in a convex shape composed of a fixing structure 404 and a sealing material 405, and the flow path connection portion 403 is provided at the other end of the flow path 401a in a concave shape so that the flow path connection portion 402 fits into it.

[0039] Here, as shown in FIG. 4C, the fixing structure 404 has a first protrusion 404a having a first hole 406 connected to the flow channel 401a, and a second protrusion 404b formed on the outer periphery of the first protrusion 404a. The first protrusion 404a and the second protrusion 404b form a fixing recess 404c for removably fixing the sealant 405. That is, the protruding portion of the sealant 405 is sandwiched and fixed between the side surface of the first protrusion 404a and the side surface of the second protrusion 404b. Note that it is sufficient that the first hole 406 is entirely or partially connected to the flow channel 401a and allows the sample liquid to pass through.

[0040] Sealing material 405 is made of a material, such as an elastic body, that is softer than the housing of the electrolyte measurement structure, and is a member that can be attached and detached from the housing (fixed structure 404). This sealing material 405 has a front surface (the upper surface in the views shown in Figs. 4C and 4D) designed to contact another electrolyte measurement structure, and a back surface (the lower surface in the views shown in Figs. 4C and 4D) designed to contact fixed structure 404 (first protrusion 404a).

[0041] That is, the front surface of the sealant 405 is the surface that comes into contact with another electrolyte measurement structure when the electrolyte measurement structure is connected to the housing. The back surface of the sealant 405 is the surface that comes into contact with the fixing structure of the electrolyte measurement structure. Therefore, when connecting a plurality of electrolyte measurement structures, the front surface of the sealant 405 comes into contact with and is pressed against the other electrolyte measurement structure, and the back surface of the sealant 405 comes into contact with and is pressed against the fixing structure 404, respectively, thereby preventing the sample liquid passing through the flow channel 401a from leaking to the outside.

[0042] The sealing material 405 is formed by integrally molding a sheet-shaped region 405a and a protruding region 405b provided on the outer peripheral side surface of the sheet region 405a and sandwiched between the fixing recesses 404c.

[0043] Seat region 405a is a portion that covers the inside (channel 401a side) of fixing recess 404c of fixing structure 404, and has second hole 407 that is arranged at a position corresponding to first hole 406 when sealing material 405 is fixed to fixing structure 404. The position at which second hole 407 is provided may be such that when fixed to fixing structure 404, all or a part of the hole is connected to first hole 406 and sample liquid can pass through.

[0044] The protruding region 405b is provided at a position corresponding to the fixing recess 404c of the fixing structure 404, and is formed on the outer peripheral side surface of the seat region 405a so as to protrude from the seat region so as to be sandwiched between the fixing recess 404c. It is preferable that the seal material 405 is pressed and fixed in the fixing recess 404c as described above. In this case, the width of the protruding region 405b of the seal material 405 may be formed to be larger than the width of the fixing recess 404c. In this way, the protruding region 405b is pressed and fixed by the side surface of the first protrusion 404a and the side surface of the second protrusion 404b, and a high fixing force can be maintained.

[0045] This sealing material 405 has a first protrusion amount, defined below, greater than a second protrusion amount when it is fixed to the fixed structure 404 and not in contact with other electrolyte measurement structures. Here, the first protrusion amount is the protrusion amount at a first location when the most protruding part on the surface of the sheet region 405a is defined as a first location, and the second protrusion amount is the protrusion amount at a second location when the most protruding part on the surface of the protrusion region 405b is defined as a second location.

[0046] These protrusion amounts can also be referred to as the protrusion amounts in the detachment direction when attaching and detaching multiple electrolyte measurement structures, and for example, it is preferable to set them as protrusion amounts in the direction along the central axis of the first hole 406 of the fixing structure 404.

[0047] More specifically, in the surface (front surface) of sealing material 405 that contacts another electrolyte measurement structure, when the protruding surface of the fixed structure (the surface above first protrusion 404a in FIG. 4C) is taken as the reference surface, the vertical distance from the reference surface is taken as the protrusion amount. Furthermore, the part on the surface of sheet region 405a that protrudes the most is taken as the first location, and the part on the surface of protrusion region 405b that protrudes the most is taken as the second location. At this time, the sealing material is formed so that the protrusion amount at the first location is greater than the protrusion amount at the second location.

[0048] 4A to 4D is an example in which the first portion is a portion adjacent to the second hole 407 in the sheet region 405a, and the second portion is the entire region of the protruding region 405b (with the same protruding amount). In this case, the protruding amount of the first portion is greater than the protruding amount of the second portion, and when connected to another electrolyte measurement structure, the first portion is reliably sealed, and the second portion is not in contact with the other electrolyte measurement structure, or even if it is in contact, the pressure is weak.

[0049] Therefore, when the electrolyte measurement structures are pulled apart from each other from their connected state, the surface of the sealing material (particularly the surface of the sheet region 405a) that comes into contact with the housing of the other electrolyte measurement structure moves away from the protrusion region 405b side, thereby preventing the sealing material 405 and the other electrolyte measurement structure from adhering to each other.

[0050] In the sheet region 405a of the sealing material 405, the relationship of the above-mentioned protrusion amount is formed such that the average thickness decreases from the second hole 407 side toward the outer periphery of the sheet region 405a, and the relationship between the above-mentioned protrusion amount and thickness is approximately the same. Note that the average thickness in this specification means the average value of the thickness in the circumferential direction formed at the same distance from the second hole of the sealing material 405 as the center.

[0051] In this case, it is preferable that the protrusion amount of a portion of sheet region 405a farther from the first portion (a portion on the outer periphery side) is smaller than the protrusion amount of the first portion, with second hole 407 as a reference. In this way, the contact area with other electrolyte measurement structures can be reduced, and adhesion can be further suppressed. It is also preferable that the first portion is provided at a portion adjacent to second hole 407, in which case the contact area with other electrolyte measurement structures can be further reduced, and adhesion can be further suppressed.

[0052] 4D, when the sealing material 405 is removed from the electrolyte measurement structure (fixing structure 404), the shape of the protruding region 405b (upper part of the protruding region) provided on the outer periphery of the seat region 405a changes. In this specification, the part where the shape changes (the part where the shoulder is dropped) is referred to as the "peripheral region" of the sealing material 405.

[0053] 4D, in the surface of the sealing material in this peripheral region, the average gradient (protrusion amount fluctuation rate) of the surface of sheet region 405a is smaller than the average gradient (protrusion amount fluctuation rate) of the surface of protrusion region 405b. That is, the gradient of protrusion region 405b is larger than the gradient of sheet region 405a.

[0054] For example, in the seat area 405a, when the contact surface with the first protrusion when fixed to the fixed structure (the back surface of the seat area 405a) is taken as a horizontal plane, this inclination can be expressed as an inclination angle with respect to the horizontal plane, and is preferably 2 to 10 degrees. Also, the inclination angle of the protrusion area 405b with respect to the horizontal plane is preferably 20 to 40 degrees.

[0055] In this way, in Fig. 4D, the peripheral region of the protruding region 405b is depressed, but when this is fixed to the electrolyte measurement structure (fixing structure 404), the protruding region 405b is preferably formed so as to be pressed by the fixing recess 404c. Therefore, the pressing causes elastic deformation and rises, and as shown in Fig. 4C, the protruding amount in the protruding region 405b becomes approximately equal over the entire region of the protruding region 405b. Note that this is just one example, and the protruding amount of the protruding region 405b may vary in any way as long as the relationship that the protruding amount of the second portion of the sheet region 405a is smaller than the protruding amount of the first portion of the sheet region 405a is maintained, as described above.

[0056] In addition, in this embodiment, the above-mentioned average gradient relationship may or may not be satisfied, but if it is satisfied, it is preferable because this can suppress an increase in the amount of protrusion of the surface of protrusion region 405b (peripheral region of sealing material 405) when sealing material 405 is attached.

[0057] In addition, it is preferable that the average thickness and the average protrusion amount in the sheet region 405a are gradually decreased from the first portion where the protrusion amount is the largest to the connection portion of the protrusion region as shown in FIG. 4D. In this case, when the electrolyte measurement structures are separated from each other, the separating force acts efficiently while the peripheral side of the sheet region 405a is separating. On the other hand, the thickness becomes thinner and the protrusion amount becomes smaller toward the periphery, so that the structures separate quickly and are less likely to be fixed to other electrolyte measurement structures and be taken away.

[0058] Furthermore, in FIG. 4C, the sheet portion 312 and the first protrusion 309 are in close contact with each other, but this is not necessarily required. As shown in FIG. 5, even if the sheet region 405a is deformed when the protrusion region 405b is fixed to the fixing recess 404c, creating a space between the sheet region 405a and the first protrusion 404a, the stagnation of the sample liquid passing through the flow path 401a can be effectively suppressed as long as there is contact near the flow path 401a.

[0059] The average thickness of such sealing material 405 is not limited and can be adjusted according to the electrolyte measurement structure used. For example, the thickness of the connecting portion between sheet region 405a and protrusion region 405b can be 0.1 to 0.5 mm, the thickness of the portion adjacent to second hole 407 of sheet region 405a can be 0.2 to 0.6 mm (however, this must be at least 0.05 mm thicker than the thickness of the connecting portion between sheet region 405a and protrusion region 405b), and the width of the portion fitted into the fixing recess of protrusion region 405b can be 1.0 to 1.2 mm.

[0060] More specifically, the thickness of the connecting portion (boundary) between the seat area 405a and the protruding area 405b may be 0.4 mm, and the thickness of the portion of the seat area 405a adjacent to the second hole 407 may be 0.5 mm. In this case, it is preferable that the peripheral area of ​​the protruding area 405b has a rounded shoulder so that the surface does not protrude beyond the surface of the seat area 405a.

[0061] 4A to 4D, the fixing structure 404 is a cylindrical protrusion, and the sealing material 405 is a shape in which an annular protrusion region is integrally molded on the outer peripheral side surface of a disk-shaped sheet region, but the shapes are not limited to these. However, from the viewpoint of sealing performance and ease of manufacture and handling, it is preferable that the basic shape of the sealing material 405 is a circle as shown in FIGS. 4A to 4D.

[0062] As another example of the structure, as shown in Fig. 6, when sealing material 405 is removed from the electrolyte measurement structure, the surface of sealing material 405 is flat (flat) without any gradient in sheet area 405a, and the back surface of sealing material 405 is formed to have a gradient. Fig. 6 shows a structure in which the average thickness of sheet area 405a varies in the same way as sealing material 405 shown in Fig. 4D, and the back surface of sealing material 405 has a structure in which sheet area 405a protrudes toward fixed structure 404 as it approaches second hole 407. When sealing material 405 of Fig. 6 is attached to a housing, the structure is the same as the electrolyte measurement structure shown in Fig. 4C.

[0063] As described above, the sealant 405 is made of an elastic material, and is made of a material softer than the housing of the electrolyte measurement structure. If the sealant 405 is too soft, the protruding region 405b is not easily fixed in the fixing recess 404c, and if the sealant 405 is too hard, the protruding region 405b does not fit in the fixing recess 404c. Therefore, it is preferable that the material of the sealant 405 has a rubber hardness of 60 to 80.

[0064] When sealing material 405 is made of an elastic body, it is preferable from the viewpoint of manufacturing that the surface is formed with a smooth curvature as shown in Fig. 7. When formed with a curvature in this way, it is preferable to regard the portion that includes the entire region through which the sample liquid passes and extends in the axial direction of the second hole as second hole 407. In other words, when the inner surface of second hole 407 of the sealing member protrudes toward the center of the second hole, the protruding portion is also considered to be the second hole.

[0065] At this time, the first point is positioned adjacent to the second hole, and the first point that is finally separated is the smallest and is located closest to the center of the sealing material 405, thereby reducing the amount of stagnant sample liquid while more significantly preventing the sealing material from adhering to and being carried away by other electrolyte measurement structures when multiple electrolyte measurement structures are disconnected.

[0066] Also, in FIG. 7, the boundary between the sheet area 405a and the protrusion area 405b is the starting point for forming the protrusion area 405b (the starting point on the back surface of the sheet member that changes with a curvature from the flat surface of the sheet area in preparation for forming the protrusion area).

[0067] The above-described configuration can reduce the amount of sample liquid remaining, and suppress the sealant from adhering to and being carried away by other electrolyte measurement structures when multiple electrolyte measurement structures are disconnected. This phenomenon is thought to occur due to, for example, the adhesive force of the sealant, the adhesive force generated by the drying of the test solution, or the test solution acting as a sealant between the sealant and other electrolyte measurement structures, causing the sealant to act like a suction cup when the structures are disconnected. In particular, the adhesive force of the sealant is weak at the initial contact between the sealant and the electrolyte measurement structures due to secondary bonds (physical interactions such as hydrogen bonds and van der Waals forces) caused by the polymers constituting the sealant diffusing and adsorbing to the adhesive interface, but it is thought that the adhesive force develops into a stronger bond over time due to the generation of primary bonds (chemical interactions).

[0068] In this embodiment, in order to reduce the phenomenon of being taken away, when the connection is released, the protruding region with a small protrusion amount is first firmly fixed by the fixing recess, so that the distance between the protruding region and the other electrolyte measurement structure increases before the sheet region and they separate (while the sealing material is elastically deforming), and then the sheet region separates. Therefore, compared to the case in which the surfaces of the sealing material separate all at once as in the conventional technique of Patent Document 2, no large force is applied. Also, since the outside separates first and outside air enters, the suction cup-like effect can be reduced.

[0069] The above-described electrolyte measurement structure can be made into an ion-selective electrode by providing a sensitive membrane, an internal liquid, and electrodes, as shown in FIG.

[0070] FIG. 8 shows the results of calculating the ratio of remaining liquid, i.e., the ratio of the gap partial volume to the flow path partial volume, for the conventional structure of the flow path connection part shown in FIG. 16 and the structure of the flow path connection part of this embodiment shown in FIG. 4C, by large deformation analysis using the finite element method.

[0071] The sealing material model used a nonlinear Neo-Hooken (Beomkeun Kim et.al.: International Journal of Precision Engineering and Manufacturing, 13, pp.759-764 (2012)) model, with the set parameters of an initial shear modulus of elasticity of 3.3 MPa and a Poisson's ratio of 0.4999. As it is a rotating body, calculations were performed using a two-dimensional axisymmetric model. The analysis was performed using ANSYS Workbench 19.2 (manufactured by ANSYS, Inc.).

[0072] In the conventional flow path connecting portion structure, the percentage of residual liquid is about 0.9%, whereas in the flow path connecting portion structure of this embodiment, the percentage of residual liquid can be reduced to about 0.5%.

[0073] FIG. 9 shows the results of measuring the holding strength and adhesion strength of the sealant for the conventional flow path connecting portion structure shown in FIG. 16 and the flow path connecting portion structure of this embodiment shown in FIG. 4C.

[0074] The holding strength of the sealing material was determined by fitting the sealing material into a recess or fixing recess of the housing, applying a fast-curing adhesive to the surface of the sealing material, fixing it to a jig connected to a tensile tester, raising the jig, and measuring the maximum load until the sealing material came off.

[0075] The adhesion strength of the sealing material was determined by using a sheet-like sample of the same material and area as the sealing material, and a plate material of the same material as the casing, bringing the sample and the plate material into pressurized contact for a certain period of time, applying a fast-curing adhesive to the top surface of the sample, fixing it to a jig connected to a tensile testing machine, raising the jig, and measuring the maximum load until the sample came off.

[0076] The vertical axis in Fig. 9 represents the difference between the holding force and the adhesive force, and the value is positive when the holding force is greater than the adhesive force. Compared to the conventional structure of the flow path connection part, in the structure of the flow path connection part of this embodiment, the holding force is much greater than the adhesive force. This shows that it is possible to prevent the seal material from falling off during electrode replacement and to prevent the replacement work from becoming complicated.

[0077] FIG. 10 shows the results of measuring the surface irregularities of the conventional structure of the flow path connection part shown in FIG. 16 and the structure of the flow path connection part of this embodiment shown in FIG. 4C when a sealing material is attached to the ion selective electrode housing.

[0078] The center (0 point) of the horizontal axis in FIG. 10 indicates the center of the flow path. In the conventional structure, the peripheral portion is a protruding shape, but in the structure of this embodiment, it was found that the vicinity of the center of the flow path is the most protruding. With a structure such as that of this embodiment, when the ion selective electrode and the electrolyte measurement structure are connected, the sealing material starts to come into contact near the flow path, so that the sealing material is reliably applied near the flow path. In the portion connected to the flow path, the volume of the gap between the other electrolyte measurement structure and the sealing material can be reduced, so that the amount of the sample liquid flowing through the flow path that remains can be effectively reduced. FIG. 12 is a schematic diagram showing an example of an electrolyte measuring device using the electrolyte measurement structure of FIG.

[0079] A recording and calculation section 1271, a control section 1272, and a display section 1273 are connected to the measurement unit 1251. The measurement unit 1251 has a dilution tank 1270, ion selective electrodes 1261, 1262, 1263, a reference electrode 1255, flow path connecting structures 1254, 1256, 1260, 1264, a potential measuring section 1265, pipes 1252, 1257, 1266, a pump 1258, dispensing nozzles 1267, 1268, 1269, a reference liquid 1253, and a waste liquid tank 1259.

[0080] Here, the electrolyte measuring structures are ion selective electrodes 1261, 1262, 1263 and reference electrode 1255 and flow path connecting structures 1254, 1256, 1260, 1264.

[0081] A specimen such as blood or urine, a diluent, and an internal standard solution are dispensed by a dispensing nozzle into a dilution tank 1270. The solution in the dilution tank 1270 is sucked by a pump 1266.

[0082] The solution sucked from the dilution tank 1270 is introduced into the flow paths of the ion selective electrodes 1263, 1262, and 1261 through a pipe 1266, and is then discharged into a waste liquid tank 1259 through a pipe 1257 and a pump 1258. On the other hand, the reference solution 1253 is introduced into the flow path of the reference electrode 1255 through a pipe 1252, and is then discharged into a waste liquid tank 1259 through a pipe 1257 and a pump 1258. The terminals of the electrodes are connected to a potential measuring unit 1265.

[0083] FIG. 11 shows the results of an electrolyte concentration measurement deviation confirmation experiment conducted using the electrolyte measuring device shown in FIG. 12 for the conventional structure (conventional structure 1) of the flow path connection part shown in FIG. 15, the conventional structure (conventional structure 2) of the flow path connection part shown in FIG. 16, and the structure of the flow path connection part of this embodiment shown in FIG. 4C.

[0084] In the experiment, the deviation of the measured values ​​was evaluated when the concentration of a concentrated potassium solution (80 mmol / L or 100 mmol / L) was measured. Since the concentration measurement reflects the individual difference of the electrode used, and different electrodes had to be used in the measurement of conventional structure 2 and the evaluation of the structure of this embodiment, the deviation of the measured value of the potassium concentration was evaluated when the sealing material of conventional structure 1 was used as the sealing material in each measurement, with the electrode housing being common, and the ratio of the deviation of the measured value of the potassium concentration when the sealing material of the relevant structure was used to this value was taken as the normalized deviation.

[0085] The standardized deviation in the structure of this embodiment is about 0.6, which is smaller than the standardized deviation in the conventional structure 2, which is about 0.8.

[0086] <Modification> 13A and 13B are schematic diagrams showing other configuration examples of the flow path connection part of the electrolyte measurement structure of the present invention.

[0087] 13A shows a schematic diagram of the flow channel connection part in a state where the sealing material is attached to the electrolyte measurement structure. The structure of the range not shown in this figure is the same as the structure described above (FIGS. 4A to 4C).

[0088] In this structure, the average thickness of the seat region 405a at a position adjacent to the second hole 407 is larger than the average thickness at the connection portion of the seat region 405a with the protruding region 405b. Also, in Fig. 13A, in the seat region 405a, the first portion is formed with a width from the second hole in the circumferential direction, and the thickness of the first portion is large. Therefore, when separating a plurality of electrolyte measurement structures, by increasing the thickness of the first portion that is separated last, the elastic restoring force of the sealing material from the start to the end of the separation can support the separation of portions other than the first portion.

[0089] 13B, the surface of the sheet region 405a may have an uneven structure 1301. However, the depth of this uneven structure is set to be shallower than the difference between the average thickness of the sheet region 405a at a position adjacent to the second hole 407 and the average thickness of the connection portion of the sheet region 405a with the protruding region 405b.

[0090] With this structure, when the electrolyte measurement structure is connected, the sealant starts to come into contact with the flow path near the flow path, so that the sealant is formed near the flow path. Since the volume of the gap between the sealant and the other electrolyte measurement structure connected to the flow path can be reduced, the amount of the sample liquid flowing through the flow path that remains can be effectively reduced.

[0091] 14 is a schematic diagram showing yet another configuration example of the present invention for the flow path connection part of the electrolyte measurement structure. An enlarged view of the flow path connection part in a state where a sealant is attached to the electrolyte measurement structure is shown. The structure of the range not shown in this figure is the same as the structure described above (FIGS. 4A to 4C).

[0092] This structure shows an example in which there is a portion where the average thickness decreases from the second hole 407 in the sheet region 405a toward the outer periphery, and then there is a portion along the way where the average thickness increases toward the outer periphery.

[0093] Even in such a case, if the protrusion amount at the first location in the sheet region 405a is greater than the protrusion amount at the second location in the protrusion region 405b, the sealant 405 will start to come into contact with the electrolyte measurement structure near the flow path when it is connected to the electrolyte measurement structure, and will be sealed near the flow path. This example also has the same effect as the above embodiment, and the volume of the gap between the sealant and another electrolyte measurement structure connected to the flow path can be reduced, effectively reducing the amount of retention of a portion of the sample liquid flowing through the flow path.

[0094] As described above, the electrolyte measurement structure can be used to form an ion selective electrode, and when multiple electrolyte measurement structures are connected to form an electrolyte measurement device, it is possible to achieve two advantageous effects: it is possible to prevent the sealing material from falling off when the electrolyte measurement structure is replaced, and it is possible to reduce the amount of sample liquid remaining in the gaps of the flow path connection section, thereby reducing the impact on the measurement results.

[0095] The present invention is not limited to the above-described embodiment, but includes various modified examples. The above-described embodiment has been described in detail to clearly explain the present invention, and is not necessarily limited to those having all of the configurations described. The configuration of one embodiment can be added to, deleted from, or substituted for the configuration of another embodiment. [Explanation of symbols]

[0096] 100: Structure for electrolyte measurement 101, 401: Main unit 101a, 401a: flow path 102, 402: Flow path connection part 103, 403: Flow path connection part 300: Ion selective electrodes 301: Sensitive membrane 302: Internal fluid 303: Electrode 404: Fixed structure 404a: 1st protrusion 404b:Second protrusion 404c: Fixing recess 405: Sealing material 405a: Seat area 405b:Protrusion area 406: First hole 407: 2nd hole 1251: Measurement unit 1252, 1257, 1266: Piping 1253:Reference liquid 1254, 1256, 1260, 1264: Flow path connection structure 1255:Reference electrode 1258: Pump 1259: Waste tank 1261, 1262, 1263: Ion selective electrodes 1265: Electric potential measurement section 1267, 1268, 1269: Dispensing nozzle 1270: Dilution tank 1271: Recording and calculation section 1272: Control unit 1273: Display section

Claims

1. A structure for electrolyte measurement having a housing and a sealing material, the electrolyte measurement structure is connectable to another electrolyte measurement structure via the sealing material, The housing has a main body having a flow path therethrough and a fixing structure that fixes the sealant to the main body, the fixing structure includes a first protrusion having a first hole connected to the flow path, and a second protrusion formed on an outer periphery of the first protrusion, and a fixing recess for detachably fixing the sealing material is formed by the first protrusion and the second protrusion; the sealing material is an elastic body having a front surface designed to contact the other electrolyte measurement structure and a back surface designed to contact the fixing structure, and is integrally formed with a sheet region that is a sheet-like region and a protrusion region that is a protrusion provided on the outer peripheral side surface of the sheet region and sandwiched in the fixing recess, the seat region has a second hole disposed at a position corresponding to the first hole when the sealing material is fixed to the fixing structure; In a state in which the sealing material is fixed to the fixed structure and is not in contact with the other electrolyte measurement structure, a first protrusion amount defined as follows is greater than a second protrusion amount: The first protrusion amount is a protrusion amount of a first portion that protrudes most on the surface of the seat area, The second protrusion amount is the protrusion amount of a second portion that protrudes most on the surface of the protrusion area; a protruding amount of a portion of the seat area farther from the first portion with respect to the second hole as a reference is smaller than a protruding amount of the first portion; A structure for electrolyte measurement.

2. The structure for electrolyte measurement according to claim 1 , The structure for electrolyte measurement, characterized in that the protruding region of the sealing material is sandwiched between each side surface of the first protrusion and the second protrusion that form the fixing recess, and is pressed and fixed.

3. The structure for electrolyte measurement according to claim 1 , The first location is adjacent to the second hole. A structure for electrolyte measurement.

4. The structure for electrolyte measurement according to claim 3, An inner surface of the sealing material forming the second hole protrudes toward the center of the second hole. Electrolyte measurement structure.

5. The structure for electrolyte measurement according to claim 3, A structure for electrolyte measurement, wherein the thickness at the first location is greater than an average thickness at a connection portion of the sheet region with the protrusion region.

6. The structure for electrolyte measurement according to claim 3, When the sealing material is removed from the fixing structure, A structure for electrolyte measurement, characterized in that an average thickness and an average protrusion amount in the sheet region gradually decrease from the first location to the protrusion region.

7. The structure for electrolyte measurement according to claim 3, When the sealing material is removed from the fixing structure, a first gradient defined as follows is smaller than a second gradient when viewed in a cross section passing through a central axis of the second hole: the first gradient being an average gradient of a surface of the seating area; the second gradient being an average gradient of the surface of the protruding region; A structure for electrolyte measurement.

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

9. An electrolyte measurement device comprising the structure for electrolyte measurement according to any one of claims 1 to 7.

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