JP2021162450A - Ion selective electrode, method for manufacturing ion selective electrode, and electrolyte analyzer - Google Patents

Abstract

To stably fix an ion sensitive film based on a difficult-to-attach resin, on a support body having a flow passage for an inspection target liquid.SOLUTION: The ion selective electrode is formed by depositing an elastic member 15 with a through-hole 18 for an opening 21, on a support body 11 having the opening 21 in a flow passage for an inspection target liquid and in a partial region of the flow passage and then depositing an ion sensitive film 16 to block the through-hole 18. The angle between a surface of the ion sensitive film 16 which is in contact with the liquid and a side surface of the through-hole 18 in the elastic member 15 is at least 90 degrees. With the above configurations, an ion selective electrode with an excellent detection performance and an excellent long-term storage stability can be provided.SELECTED DRAWING: Figure 1

Description

The present invention relates to an ion-selective electrode, a method for producing an ion-selective electrode, and an electrolyte analyzer provided with the ion-selective electrode. In particular, among the analyzers used in clinical examination devices, the electrolyte analyzers used for water quality analysis, food analysis, etc. are related.

The ion-selective electrode measures a specific ion concentration in a sample such as blood, body fluid or urine, for example, sodium ion, potassium ion, chloride ion, etc., and is an electrolyte together with a reference electrode (also referred to as a reference electrode). It constitutes an analyzer. These are used as a single device or mounted on a clinical testing device, a water quality analyzer, or the like.

The flow-type ion-selective electrode is described in detail in, for example, Patent Document 1 below. The structure of the ion-selective electrode is generally an electrolyte solution, a housing for encapsulating the electrolyte solution, a support having a flow path for the test solution, and an ion-sensitive film provided between the electrolyte solution and the test solution. It is composed of an electrode rod for measuring the electromotive force induced in the ion-sensitive film.

A support that holds the ion-sensitive film is fixed to the housing, or is integrally molded with the housing. A flow path for flowing the test liquid is formed inside the support, and an opening is formed on a part of the side surface of the flow path of the test liquid. The opening is covered with an ion-sensitive membrane, and the test solution in the flow path and the electrolyte solution in the housing are physically separated from each other, and electrical conduction is obtained through the ion-sensitive membrane. It has become. At this time, the ion concentration in the test solution is measured by measuring the potential difference between the electromotive force generated in the ion-sensitive film and the reference electrode according to the ion concentration in the test solution.

In addition, the housing and support are made of polyvinyl chloride resin or acrylonitrile butadiene styrene (ABS) because of the technical need to stably enclose an electrolyte solution, which is an aqueous solution of sodium chloride, for a long period of time and the ease of production. ) Resin is used.

Conventionally, as an ion-sensitive membrane, a membrane based on a polyvinyl chloride resin has been used for sodium ions and potassium ions. Further, it is disclosed that a polymer substance itself having a quaternary ammonium salt or a polyethylene porous membrane is used as a reinforcing material for the ion-sensitive membrane for chloride ions (see, for example, Patent Document 2 below). ).

Further, the configuration of the electrolyte analyzer using the ion-selective electrode is described in detail in Patent Documents 1 and 2 below. Further, in Patent Document 3 below, in a medical device having a function of emitting an alarm sound, in order to prevent liquid from entering the speaker portion, the front and back surfaces of a circular polyethylene film are made of silicone rubber in a tubular accommodating portion. A structure is disclosed in which a laminated body sandwiched between the ring-shaped packings of the above is inserted, a speaker is inserted, and then the structure is fixed by a fixture from above.

Japanese Unexamined Patent Publication No. 2016-180630 JP-A-2018-4633 (paragraph [0007]) Japanese Unexamined Patent Publication No. 2012-196339

Conventionally, when the support is made of polyvinyl chloride resin and the ion-sensitive film is made of polyvinyl chloride resin as a base material, a method of fixing the two by a method such as adhesive or solvent adhesion has been used. The same applies when the support is made of ABS resin and the ion-sensitive film is adhesive.

However, when the ion-sensitive film is made of a polyethylene porous film as a base material, it is difficult to bond the ion-sensitive film to the support by an adhesive or welding technique because the adhesiveness is originally poor. In addition, when an adhesive is used, liquid leakage may occur due to insufficient adhesive or insufficient curing, and the adhesive may squeeze out to the measurement site of the ion-sensitive film and shield it, or the adhesive component may elute. As a result, there is a problem of causing poor performance of the ion-selective electrode.

As a method of fixing such a poorly adhesive film on a support, a method realized by a mechanical method using a fixing member is well known. However, there have been problems in ensuring mechanical stability in the state of being impregnated with the electrolyte solution and ensuring long-term reliability such as prevention of leakage of the test solution. Here, the present inventors have found that when there is a liquid pool portion in the vicinity of the measurement portion of the ion-sensitive membrane in which the flow of the test liquid is stagnant, the characteristics of the ion-selective electrode are greatly affected. Based on the above findings, the present inventors have diligently searched and investigated a method for providing a highly reliable ion-selective electrode that does not adversely affect the characteristics of the ion-selective electrode.

In view of the above problems, an object of the present invention is to be able to stably fix an ion-sensitive film based on a poorly adhesive resin on a support having a flow path of a test solution. Another object of the present invention is to provide an ion-selective electrode having excellent detection performance and long-term storage stability even if it is an ion-selective electrode using a poorly adhesive resin as a base material.

In order to achieve the above object, the ion-selective electrode of the present invention has a support having an opening in the flow path of the test solution and a part of the flow path, and a through hole having a shape corresponding to the opening. A laminate composed of an elastic member laminated at a position where the opening and the through hole match, and an ion-sensitive film laminated so as to close the upper part of the through hole, and the ion-sensitive film. It has a pressing member that uses the space formed by the opening and the through hole as a common flow path by being fixed on the support by pressing from the upper part, and has a pressing member with respect to the liquid contact surface of the ion-sensitive membrane. The elastic member is in contact with the side surface of the through hole at an angle (θa) of 90 degrees or more.

Further, the holding member may be locked to the fixing member connected and formed on the support by a locking structure, and the laminated body may be fixed to the support.

Further, the laminated body may be fixed to the support by a method of welding or adhering a part or the whole of the periphery of the holding member to the fixing member connected and formed on the support.

Further, in the common flow path, there may be no liquid storage space for the test liquid between the ion-sensitive membrane and the elastic member.

Further, the electrolyte analyzer of the present invention is characterized in that the above-mentioned ion-selective electrode is mounted.

Further, the method for producing an ion-selective electrode of the present invention is a method for producing an ion-selective electrode in which an ion-sensitive membrane is fixed to a support having an opening in a flow path of a test solution and a part of the flow path. A step of preparing the elastic member having a through hole having a shape corresponding to the opening and having an angle (θb) of a side surface of the through hole with respect to the upper surface of the elastic member of 90 degrees or less. A step of laminating the inside of the support at a position where the opening of the support and the through hole of the elastic member coincide with each other, and inside the support, the upper part of the through hole is formed by the ion-sensitive film. A step of laminating the ion-sensitive film so as to be closed with the above, and a step of pressing the ion-sensitive film from the upper part of the ion-sensitive film with a pressing member and fixing the ion-sensitive film on the support. It is characterized in that the formed space is used as a common flow path.

Further, by locking the fixing members provided on the support and the locking portions provided on the holding members with each other, the elastic member and the ion-sensitive film can be placed inside the support. The laminate may be fixed.

Further, by welding or adhering a part or all of the periphery of the holding member to the fixing member provided on the support, the elastic member and the ion-sensitive film are laminated inside the support. May be fixed.

According to the present invention, an ion-sensitive film based on a poorly adhesive resin can be stably fixed on a support having a flow path of a test solution. Further, even an ion-selective electrode based on a poorly adhesive resin can be provided with an ion-selective electrode having excellent detection performance and long-term storage stability.

FIG. 1 is an exploded view illustrating a method of attaching an ion-sensitive film to a support according to an embodiment of the present invention. FIG. 2 is an explanatory view of the flow path and the shape of the opening inside the support. FIG. 3 is an explanatory view showing the arrangement relationship between the opening of the flow path and the through hole of the elastic member. FIG. 4 is a cross-sectional view for explaining in detail the relationship of the locking structure of the ion-sensitive film inside the support. FIG. 5 is a diagram illustrating a main component of the electrolyte analyzer according to the embodiment. FIG. 6 is a cross-sectional view of a flow path formed by the support, the elastic member, and the ion-sensitive film used in each of Examples 1 to 3. FIG. 7 is a cross-sectional view of a flow path formed by the support, the elastic member, and the ion-sensitive film used in Comparative Examples 1 and 2, respectively. FIG. 8 is a chart showing an example of the measurement result of the potential change after the test solution is added using the ion-selective electrode to which the ion-sensitive membrane is fixed in Examples and Comparative Examples. FIG. 9 is a diagram illustrating various shapes of elastic members used for ion-selective electrodes. FIG. 10 is a cross-sectional view illustrating the fixing structure of the fixing member and the pressing member.

Hereinafter, the ion-selective electrode of the present invention will be described in detail. For the sake of explanation, the same reference numerals are used for the same members. Further, the test solution used in the following description refers to a solution obtained by diluting an object to be analyzed such as blood, body fluid and urine, and refers to an aqueous solution containing an electrolyte such as sodium ion, potassium ion and chloride ion.

(Outline of configuration of ion-selective electrode)
FIG. 1 is an exploded view illustrating a method of attaching an ion-sensitive film to a support according to an embodiment of the present invention. The support 11 is made of ABS resin, polyvinyl chloride resin, or the like. The support 11 may be integrally formed with the side plate 12 that also serves as a housing, or the side plate 12 and the support 11 may be made of different materials and combined by a method such as adhesion. Inside the support 11, a flow path 13 for the test liquid is formed so as to penetrate the side plate 12. In the example of FIG. 1, a frame-shaped fixing member 14 separately formed is connected and formed on the support 11, but these supports 11 and the fixing member 14 may be integrally molded by a method such as injection molding. It is possible.

Inside the fixing member 14, sheet-shaped elastic members 15 formed according to the inner shape of the fixing member 14 are laminated and arranged. The material of the elastic member 15 is a silicone rubber-based resin in addition to commercially available fluororubber-based resins such as vinylidene fluoride-based (FKM), tetrafluoroethylene-propylene-based (FEPM), and tetrafluoroethylene-purple orovinyl ether-based (FFKM). Resin or the like is preferably used from the viewpoint of water resistance and chemical resistance. At the center of the elastic member 15, a through hole 18 having substantially the same shape as the end of the opening 21 provided at the bottom of the support 11 is formed.

The ion-sensitive film 16 is arranged on the elastic member 15. The ion-sensitive film 16 is made by an existing method using a polyolefin-based resin film as a base material. By laminating the ion-sensitive film 16 on the through hole 18 of the elastic member 15, the opening 21 is closed and a flow path in a closed space is formed.

A pressing member 17 having a through frame structure penetrating vertically is inserted into the opening of the fixing member 14. Although the details will be described later, when the pressing member 17 is inserted into the fixing member 14, the locking convex portion 19a formed on the pressing member 17 engages with the locking recess 19b formed on the inner wall of the fixing member 14 to fix the pressing member 17. The inserted state of the pressing member 17 with respect to the member 14 can be fixedly held.

FIG. 2 is an explanatory view of the flow path and the shape of the opening inside the support. 2 (a) is a top view, FIG. 2 (b) is a cross-sectional view of the AA'line of FIG. 2 (a), and FIG. 2 (c) is an enlarged explanatory view of the opening. As shown in FIG. 2B, the flow path 13 has a structure that penetrates the side plate 12, travels inside the support 11, and rises toward the opening 21. As shown in FIG. 2C, the opening 21 has a structure from the entrance of the flow path 13 to the exit of the flow path through a groove formed on the support 11.

FIG. 3 is an explanatory view showing the arrangement relationship between the opening of the flow path and the through hole of the elastic member. As shown in FIGS. 2C and 3, the end 22 of the opening 21 on the support 11 has a shape straddling the inlet and outlet of the flow path 13 and has an oval shape. ing. A through hole 18 of the elastic member 15 is arranged on the opening 21.

FIG. 4 is a cross-sectional view for explaining in detail the relationship of the locking structure of the ion-sensitive film inside the support. FIG. 4 is a cross section of the BB'line of FIGS. 2 and 3, showing a laminated structure of each part inside the support 11 and a locking structure of the ion-sensitive film 16.

An oval opening 21 serving as a flow path 13 for the test liquid is formed in the central portion of the support 11, and a frame-shaped fixing member 14 is fixed to the upper portion of the support 11. .. By inserting a pressing member 17 having a through frame structure (communication portion 17a) penetrating vertically into the frame of the fixing member 14, the laminated body in which the elastic member 15 and the ion-sensitive film 16 are laminated is formed by the pressing member 17. The lower frame portion 17b is configured to be pressed from the upper portion of the ion-sensitive film 16 toward the support 11.

As shown in FIG. 4, in a state where the sheet-shaped elastic member 15 is inserted into the frame of the fixing member 14, the opening 21 of the support 11 and the through hole 18 of the elastic member 15 are at the same position (match). Since it is located at the position), the space covered by the ion-sensitive film 16 is formed as a common flow path 13. In the laminated structure composed of these elastic members 15 and the ion-sensitive film 16, the locking convex portion 19a formed on the pressing member 17 engages with the locking concave portion 19b formed on the inner wall of the fixing member 14. It is pressed and fixed on the support 11 by the acting spring force and the elastic force of the elastic member 15.

In the production of the ion-selective electrode described above, a laminate of the elastic member 15 and the ion-sensitive film 16 is laminated inside the support 11. At this time, by laminating at a position where the opening 21 of the support 11 and the through hole 18 of the elastic member 15 match, the upper portion of the through hole 18 of the elastic member 15 is closed by the ion-sensitive film 16 and the opening is opened. The space formed by the 21 and the through hole 18 can be formed as a flow path of the test solution. After that, by fixing the pressing member 17 having the connecting portion 17a to the support 11, the laminated body of the elastic member 15 and the ion-sensitive film 16 can be fixed inside the support 11. The pressing member 17 can be fixed to the support 11 by a locking structure, welding or adhesion.

An ion-selective electrode is formed by combining an electrode rod and a housing member with a support 11 provided with an ion-sensitive film 16 having the above configuration by a well-known method, and finally encapsulating an internal electrolytic solution. Can be done.

(Configuration of electrolyte analyzer)
FIG. 5 is a diagram illustrating a main component of the electrolyte analyzer according to the embodiment. A plurality of ion-selective electrodes 53 (sodium ion-selective electrode 53-1, potassium ion-selective electrode 53-2, chloride ion-selective electrode 53) provided with each ion-sensitive film (for example, the ion-sensitive film 16). -3), the reference electrode 54 (indicated as Ref in FIG. 5), and the temperature sensor 55 are arranged along the flow path of the test solution 52. The test liquid 52 that has entered the pot 51 is sucked by the electromagnetic pump 56 via the flow path of each electrode.

The electromotive force induced in the ion-sensitive film is measured by an electrode rod (not shown) fixed to the housing member, and is input to the temperature compensation circuit 57 together with the potential of the reference electrode 54 and the information of the temperature sensor 55.

As for the electromotive force of each ion-selective electrode 53 of sodium ion, potassium ion and chloride ion, the potential difference with the potential of the reference electrode 54 as the system ground is measured by the external arithmetic circuit 58 and displayed on the display 59.

As these electrolyte analyzers, a fully automatic electrolyte analyzer EA07 (applicant, manufactured by A & T Corporation) or the like can be commercially used. As the ion-sensitive membrane used as the ion-selective electrode 53 of the present invention, known ones used in various ion-selective electrodes can be used without particular limitation.

Hereinafter, the present invention will be specifically shown with reference to examples, but the present invention is not limited to these examples.

In this embodiment, the ion-selective electrode 53 in which the ion-sensitive membrane for chloride ions is fixed by the present production method is connected to the electrolyte analyzer shown in FIG. 5, and the response speed of the potential difference fluctuation from the injection of the test solution Was measured. At this time, with respect to the ion-selective electrode 53, the shape of the common flow path 13 formed by the opening 21 of the support 11 and the through hole 18 of the elastic member 15 was changed, and the behavior of each potential difference change was measured. ..

(Examples 1 to 3)
FIG. 6 is a cross-sectional view of a flow path formed by the support, the elastic member, and the ion-sensitive film used in each of Examples 1 to 3. ABS resin was used for the support 11, and a commercially available fluororubber sheet was used for the elastic member 15. The shape of the through hole 18 of the elastic member 15 was created by changing the mold shape using a general compression molding technique. The rubber hardness of the elastic member 15 at this time is preferably about 40 to 80, more preferably about 70 because the degree of deformation at the time of pressing is small and the liquid leakage is small.

FIG. 6A shows an example in which the angle (θa) formed by the side surface 62 of the through hole 18 of the elastic member 15 with respect to the liquid contact surface 61 of the ion-sensitive film 16 is 90 degrees. 6 (b) shows that the angle (θa) of the elastic member 15 is the same as that of FIG. 6 (a), but the shape of the side surface 62 of the through hole 18 on the side in contact with the support 11 is curved. (Curved portion 62a) is different. FIG. 6C shows an example in which the angle (θa) is 90 degrees or more by inclining the shape of the side surface 62 of the through hole 18.

(Comparative Examples 1-2)
FIG. 7 is a cross-sectional view of a flow path formed by the support, the elastic member, and the ion-sensitive film used in Comparative Examples 1 and 2, respectively. A comparative example in which the structure of the side surface 62 of the through hole 18 of the elastic member 15 is different from that of Examples 1 to 3 is shown. Both FIGS. 7 (a) and 7 (b) are examples in which the angle (θa) formed by the side surface 62 of the through hole 18 with respect to the wetted surface 61 of the ion-sensitive film 16 is 90 degrees or less. FIG. 7A further has a curved portion 62a whose shape on the side surface 62 of the through hole 18 in contact with the support 11 is curved.

FIG. 8 is a chart showing an example of the measurement result of the potential change after the test solution is added using the ion-selective electrode to which the ion-sensitive membrane is fixed in Examples and Comparative Examples. In the figure, the horizontal axis represents time and the vertical axis represents the potential of the ion-selective electrode. It is shown that after the test solution is added, the potential drops sharply from the initial stable potential state and changes to a predetermined potential according to the ion concentration.

FIG. 8A is a measurement result when the elastic member 15 having the cross-sectional shape shown in Example 1 (FIG. 6A) is used and the angle θa is 90 degrees. FIG. 8B is a measurement result when the elastic member 15 having the cross-sectional shape shown in Comparative Example 1 (FIG. 7A) is used. From the result of FIG. 8A, it can be seen that in Example 1, the time (response time) until reaching the predetermined potential is about 0.5 seconds, and the potential after that is also stable. On the other hand, in the result of Comparative Example 1 shown in FIG. 8B, it takes about 2 seconds. Here, it has also been found that the shape of the side surface 62 of the through hole 18 on the side where the side surface 62 comes into contact with the support 11 does not affect the response time.

Table 1 below shows the measurement results of Examples 1 to 3 and Comparative Examples 1 and 2. From the results in Table 1, the present inventors have found that when θa is 90 degrees or more, the liquid of the test liquid is accumulated in the space formed by the liquid contact surface of the ion-sensitive membrane and the side surface 62 of the through hole 18. It is estimated that the time required for liquid replacement will be longer.

(Examples 4 to 5, Comparative Example 3)
FIG. 9 is a diagram illustrating various shapes of elastic members used for ion-selective electrodes. For each elastic member, a sheet made of a fluororesin having a rubber hardness of about 70 similar to that in Example 1 was used, and a desired shape was formed by compression molding using a mold.

9 (a) and 9 (b) are Examples 4 and 5, and FIG. 9 (c) is Comparative Example 3. In Example 4 shown in FIG. 9A and Example 5 shown in FIG. 9B, the angles (θb) of the side surface 62 of the through hole 18 with respect to the upper surface of the elastic member 15 are 90 degrees and 60 degrees, respectively. Is shown. In Comparative Example 3 of FIG. 9C, the angle θb is about 140 degrees. Using these elastic members 15, an ion-selective electrode was prepared by the same method as described above, connected to an electrolyte analyzer, and the potential change after the test solution was added was measured in the same manner as shown in Table 2 below. show.

From the results in Table 2, it can be seen that the response time is short when the angle (θb) of the side surface 62 of the through hole 18 with respect to the upper surface of the elastic member 15 is 90 degrees or less. In this case as well, the liquid contact surface 61 of the ion-sensitive membrane 16 and the side surface 62 portion of the through hole 18 have an angle of 90 degrees or more on the flow path side, and the liquid does not accumulate, so that the predetermined potential is reached. It can be inferred that the time is short.

(Other Examples)
In the above embodiment, a method of mechanically fixing the fixing member 14 and the pressing member 17 by a locking structure has been described mainly with reference to FIG. As another application example, it is also useful to fix the fixing member 14 and the pressing member 17 by welding or adhesion. In this case, the fixing member 14 and the pressing member 17 may be mechanically fixed by a locking structure, and the fixing member 14 and the pressing member 17 may be further fixed by welding or adhesion.

FIG. 10 is a cross-sectional view illustrating the fixing structure of the fixing member and the pressing member. The contact surface between the fixing member 14 and the pressing member 17 shown in FIG. 10 can be welded and fixed by an ultrasonic welder or the like. Also in this structure, a connecting portion 17a is provided at the center of the pressing member 17 so that the electrolyte solution of the ion-selective electrode 53 and the ion-sensitive membrane 16 can come into contact with each other.

The advantage of the fixing method shown in FIG. 10 is that the productivity can be improved because the shape is simple without using a complicated structure such as the locking structure (see FIG. 4) described above. Here, it is possible to bond using an adhesive other than welding and fixing, but in the case of bonding, it is necessary to consider contamination of the surface of the ion-sensitive film 16 due to the lengthening of the curing reaction.

The ion-selective electrode, the method for producing an ion-selective electrode, and the electrolyte analyzer of the present invention can stably fix a poorly adhesive ion-sensitive film, and are an electrolyte analyzer and the like that measure various electrolyte concentrations of a test solution. Can be applied to.

11 Support 12 Side plate 13 Flow path 14 Fixing member 15 Elastic member 16 Ion-sensitive film 17 Holding member 17a Connecting part 18 Through hole 19a Locking convex part 19b Locking recess 21 Opening 22 Opening end 51 Pot 52 Inspected Liquid 53 Ion-selective electrode 54 Reference electrode 55 Temperature sensor 56 Electromagnetic pump 57 Temperature compensation circuit 58 Calculation circuit 59 Display 61 Liquid contact surface 62 Side surface of through hole 18 62a Curved part

Claims (8)

A flow path of the test solution, a support having an opening in a part of the flow path, and a support
An elastic member having a through hole having a shape corresponding to the opening and being laminated at a position where the opening and the through hole match.
A laminated body composed of an ion-sensitive film laminated so as to close the upper part of the through hole, and
It has a pressing member that holds the space formed by the opening and the through hole as a common flow path by pressing from the upper part of the ion-sensitive film and fixing it on the support.
An ion-selective electrode characterized in that the angle (θa) formed by the side surface of the through hole of the elastic member with respect to the liquid contact surface of the ion-sensitive film is 90 degrees or more. The ion-selective electrode according to claim 1, wherein the holding member is locked to the fixing member connected and formed on the support by a locking structure, and the laminated body is fixed to the support. .. The first aspect of the present invention is characterized in that the laminated body is fixed to the support by a method of welding or adhering a part or the whole of the periphery of the pressing member to the fixing member connected and formed on the support. The ion-selective electrode according to the description. The ion-selective electrode according to any one of claims 1 to 3, wherein the common flow path has no liquid storage space for the test liquid between the ion-sensitive membrane and the elastic member. .. An electrolyte analyzer comprising the ion-selective electrode according to any one of claims 1 to 4. In a method for manufacturing an ion-selective electrode for fixing an ion-sensitive membrane to a support having an opening in a flow path of a test solution and a part of the flow path.
A step of preparing an elastic member having a through hole having a shape corresponding to the opening and having an angle (θb) of a side surface of the through hole with respect to the upper surface of the elastic member of 90 degrees or less.
A step of laminating the inside of the support at a position where the opening of the support and the through hole of the elastic member match.
A step of laminating the upper part of the through hole so as to be closed by the ion-sensitive film inside the support.
A step of pressing the ion-sensitive film from the upper part of the ion-sensitive film with a pressing member and fixing the ion-sensitive film on the support is included.
A method for producing an ion-selective electrode, which comprises using a space formed by the opening and the through hole as a common flow path. By locking the fixing member provided on the support and the locking portion provided on each of the pressing member to each other, the elastic member and the ion-sensitive film are laminated inside the support. The method for producing an ion-selective electrode according to claim 6, wherein the ion-selective electrode is fixed. By welding or adhering a part or all of the periphery of the holding member to the fixing member provided on the support, the laminated body of the elastic member and the ion-sensitive film is fixed inside the support. The method for producing an ion-selective electrode according to claim 6, wherein the ion-selective electrode is made.

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