Ion-selective electrodes

Abstract

Provided is an all-solid ion-selective electrode with which it is possible to further stabilize measurement values. An all-solid ion-selective electrode comprising a working electrode and an ion-responsive film is characterized in comprising an ion-electron conversion layer that is positioned between the working electrode and the ion-responsive film and that electrically connects the working electrode and the ion-responsive film. The all-solid ion-selective electrode is furthermore characterized in that the ion-electron conversion layer contains an ion-electron conversion substance and a polymer, or contains a polymer having an ion-electron conversion function.

Description

[Technical Field]

[0001] The present invention relates to an ion-selective electrode. [Background technology]

[0002] As an all-solid-state ion-selective electrode that does not use an internal liquid, as described in Non-Patent Document 1, a layer consisting of only carbon nanotubes that electrically connects a metal working electrode to an ion-responsive membrane is provided on the surface of the working electrode, and an ion-responsive membrane is laminated on the surface of this carbon nanotube layer facing the sample solution. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] “Ion-Selective Electrodes Using Carbon Nanotubes as Ion-to-Rlectron Transducers”, Gaston A. Crespo et al, Anal. Chem., 80, 1316-1322 (2008) [Non-patent document 2] “Solubility parameters for optimal determining solvents for separating PVC from PVC-coated PET fibers”Guido Grause et al., J. Mater. Cycles Waste Manag., 19(2), 612-622(2017) Summary of the Invention [Problem to be solved by the invention]

[0004] However, when this conventional all-solid-state ion-selective electrode was actually used to measure ion concentrations, the inventors noticed that the measured values ​​sometimes drifted. After extensive research into the cause of the drift in the measured values, the present inventors came to the conclusion that the cause may be the presence of carbon nanotubes in the ion-responsive membrane.

[0005] When manufacturing a conventional all-solid-state ion-selective electrode, after forming a carbon nanotube layer, the material of the ion-responsive membrane is suspended in an organic solvent and dripped onto the surface. During this process, the carbon nanotubes constituting the carbon nanotube layer dissolve in the organic solvent contained in the ion-responsive membrane material, and the carbon nanotubes become mixed into the ion-responsive membrane. It was thought that if the carbon nanotubes are mixed into the ion-responsive membrane in this way, the sample solution and the carbon nanotubes mixed into the ion-responsive membrane would react directly, causing drift in the measurement value.

[0006] The present invention has been made in view of the above-mentioned problems, and aims to provide an all-solid-state ion-selective electrode that can suppress the incorporation of ion-electron conversion substances such as carbon nanotubes into the ion-responsive membrane and thereby achieve more stable measurement values. [Means for solving the problem]

[0007] That is, the all-solid-state ion-selective electrode according to the present invention comprises a working electrode and an ion-responsive membrane, and an ion-electron conversion layer disposed between the working electrode and the ion-responsive membrane to electrically connect them, wherein the ion-electron conversion layer contains an ion-electron conversion material and a polymer, or contains a polymer having ion-electron conversion function.

[0008] In such an all-solid-state ion-selective electrode, the ion-electron conversion layer contains a polymer, so the ion-electron conversion substance in the ion-electron conversion layer is protected by the polymer and is less likely to elute, thereby preventing the ion-electron conversion substance from being mixed into the ion-responsive membrane.

[0009] If the entire surface of the ion-electron conversion layer on the sample solution side is covered by the ion-responsive membrane, there is no need to provide a separate sealing member to prevent the ion-electron conversion material in the ion-electron conversion layer from coming into direct contact with the sample solution.

[0010] In a specific embodiment of the present invention, the ion-electron conversion material contains at least one material selected from the group consisting of carbon nanotubes, graphene, and graphite.

[0011] If the polymer has adhesive properties, the ion-electron conversion layer also serves as an adhesive layer, and therefore, an all-solid-state ion-selective electrode can be produced simply by laminating the ion-electron conversion layer on the working electrode and then laminating the ion-responsive membrane on the ion-electron conversion layer.

[0012] When a carbon microstructure such as a carbon nanotube is used as the ion-electron conversion material, the carbon microstructure may adsorb oxygen, which may change the properties of the ion-electron conversion material. Therefore, the polymer should have an oxygen permeability of 0.05 cc / m 2 / day or more 50000cc / m 2 It is preferable that it is less than / day. Furthermore, if the polymer is oxygen impermeable, there is no need to use a polymer with low oxygen permeability for the ion-responsive membrane, which broadens the options for materials for the ion-responsive membrane.

[0013] If the polymer is resistant to the solvent used in producing the ion-responsive membrane, the ion-electron conversion layer can be prevented from dissolving in the solvent, thereby further preventing the ion-electron conversion material or the polymer having ion-electron conversion function from eluting from the ion-electron conversion layer.

[0014] In a specific embodiment of the present invention, the polymer is a fluoropolysiloxane. [Effects of the Invention]

[0015] According to the present invention, the measured values ​​of an all-solid-state ion selective electrode can be made more stable than ever before. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a schematic diagram showing the entire ion concentration measuring device according to an embodiment of the present invention; [Figure 2] FIG. 1 is a schematic diagram showing a sensor unit according to an embodiment of the present invention. [Figure 3] 1A and 1B are schematic cross-sectional views of an ion-selective electrode and a reference electrode according to an embodiment of the present invention. [Figure 4] 1 is a graph showing the results of sodium ion measurement using ion selective electrodes according to examples and comparative examples of the present invention. [Figure 5] FIG. 10 is a schematic diagram showing a sensor unit of an ion concentration measuring device according to another embodiment of the present invention. [Explanation of symbols]

[0017] 100 Ion concentration measuring device 1. Sensor unit 121 Ion-selective electrodes 121a...Working electrode 121b···Ion-responsive membrane 121c···Ion-electron conversion layer 122...Reference electrode DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1 , the ion concentration measuring device 100 according to this embodiment includes a sensor unit 1 that comes into contact with a sample solution and detects ions and the like contained in the sample solution, a calculation unit 2 that calculates the ion concentration and the like based on the output value output from the sensor unit 1, a display unit 3 that displays the measurement values ​​and the like calculated by the calculation unit 2, and a control unit 4 that controls the calculation unit 2 and the display unit 3.

[0019] The sensor unit 1 includes, for example, as shown in FIG. 2, a film-like substrate 11 approximately 3 cm long, 1 cm wide, and 0.5 mm thick, made of a liquid crystal polymer, polyvinyl chloride, polyethylene terephthalate, or the like, and an electrode portion 12 provided on the substrate 11.

[0020] In this embodiment, the calculation section 2 is performed by an information processing circuit 5 provided separately from the sensor unit 1 . The information processing circuit 5 includes a digital circuit configured with a CPU, memory, communication port, etc., an analog circuit equipped with a buffer and amplifier, etc., and an AD converter, DA converter, etc. that mediate between the digital circuit and the analog circuit. The CPU and its peripheral devices work together in accordance with a predetermined program stored in the memory, causing the information processing circuit 5 to function as the calculation unit 2.

[0021] The electrode section 12 will be described in detail below. The electrode unit 12 includes, for example, an ion-selective electrode 121 and a comparison electrode 122, each of which is connected to the information processing circuit 5 by a printed wiring P formed on the substrate 11, as shown in FIG. 2.

[0022] In this embodiment, the ion selective electrode 121 is, for example, a sodium ion selective electrode that measures the sodium ion concentration of a sample solution. The ion-selective electrode 121 is an all-solid-state type, and as shown in FIG. 3(a), includes a flat working electrode 121a arranged on the substrate 11 so as to be electrically connected to the printed wiring P, an ion-responsive membrane 121b formed so as to cover the working electrode 121a, and an ion-electron conversion layer 121c arranged between the working electrode 121a and the ion-responsive membrane 121b.

[0023] The working electrode 121a is made of a metal such as silver or platinum. The ion-responsive membrane 121b is formed so as to cover the ion-electron conversion layer 121c, and contains an ion-responsive substance and a polymer (polymer for ion-responsive membrane). In this embodiment, as an example, a material containing 4-tert-Butylcalix[4]arene-tetraacetic acid tetraethyl ester as the ion-responsive substance and polyvinyl chloride (hereinafter also referred to as PVC) as the polymer for the ion-responsive membrane will be described.

[0024] The ion-responsive membrane 121b is formed by dissolving the ion-responsive substance and the ion-responsive membrane polymer in an appropriate solvent (ion-responsive membrane solvent), applying the solution to the ion-electron conversion layer 121c, and drying and curing it. In this embodiment, tetrahydrofuran, an organic solvent that easily dissolves PVC used as the ion-responsive membrane polymer, is used as an example of the ion-responsive membrane solvent.

[0025] In this specification, whether a solvent can easily dissolve a certain polymer is defined using, for example, the following equation 1.

[0026]

number

[0027] The Q was calculated from the change in mass of a 0.2 g test piece when the test piece was immersed in 5 ml of a solvent at 20° C. for 30 minutes. Regarding whether a polymer is easily soluble, if the value of Q is 2 or more, it is judged to be easily soluble, and if the value of Q is 10 or more, it is judged to be very easily soluble.

[0028] Therefore, it is preferable to use a solvent for the ion-responsive membrane such that the Q value calculated using a test piece made of PVC is 2 or more, and it is more preferable to use a solvent for the ion-responsive membrane such that the Q value is 10 or more.

[0029] For PVC, examples of solvents that give a Q value of 10 or more include tetrahydrofuran, cyclohexanone, cyclopentanone, dimethylacetamide (DMA), pyridine, 3-pentanone, 2-pentanone, dimethylformamide (DMF), and methyl ethyl ketone (MEK).

[0030] Examples of solvents that give a Q value of 2 or more for PVC include dichloromethane, 4-methylpent-2-one, nitrobenzene, 1,4-dioxane, 1,1,2,2-tetrachloroethane, acetone, ethyl acetate, and chloroform.

[0031] The comparison electrode 122 functions as a reference electrode for the ion-selective electrode 121, and as shown in FIG. 3(b), comprises a flat comparison electrode 122a arranged on the substrate 11 so as to be electrically connected to the printed wiring P, and a salt bridge layer 122b attached so as to cover the comparison electrode 122a.

[0032] The comparison electrode 122a is preferably made of, for example, a metal that is resistant to oxidation, and specific examples include a silver / silver chloride electrode, a silver electrode, and a carbon electrode. The salt bridge layer 122b electrically connects the comparison electrode 122a and the sample solution, and is, for example, a gel-like internal liquid.

[0033] The ion-electron conversion layer 121c contains, for example, an ion-electron conversion material and a polymer (polymer for ion-electron conversion layer). As the ion-electron conversion material, for example, a carbon microstructure can be used.

[0034] The carbon microstructure may include, for example, one or more selected from carbon nanotubes, carbon nanofibers, carbon nanowalls, fullerenes, graphite, graphene, etc. In this embodiment, carbon nanotubes are used as an example of the ion-electron conversion material. The content of the carbon microstructure in the ion-electron conversion layer 121c is preferably 0.001 mass% or more and 12.0 mass% or less, more preferably 0.001 mass% or more and 0.02 mass% or less, and even more preferably 0.003 mass% or more and 0.01 mass% or less.

[0035] The polymer for the ion-electron conversion material is not particularly limited, and may be, for example, a natural resin or a synthetic resin. The natural resin may be any of plant-derived natural resins, animal-derived natural resins, and mineral-derived natural resins.

[0036] The synthetic resin may be one or more selected from the group consisting of polyvinyl chloride (PVC), polystyrene, polyvinyl butyral, polyamide resins, polyimide resins, polyurethane resins, PTFE, silicone resins, polyvinylidene fluoride-hexafluoropropylene copolymers, acrylic resins, epoxy resins, polyolefins, and crude rubber. Examples of the silicone resin include fluoropolysiloxane, polydimethylsiloxane, and polysiloxane. Examples of the acrylic resin include polyacrylate, polymethacrylate, and polybutyl acrylate. Examples of the polyamide resin include polyamide, aliphatic polyamide, and polyphthalamide. Examples of the polyimide resin include aliphatic polyimide and aromatic polyimide. Examples of the polyurethane resin include glycol-based polyurethane and amine-based polyurethane.

[0037] The polymer for the ion-electron conversion layer has an oxygen permeability of 0.05 cc / m 2 so that the ion-electron conversion material in the ion-electron conversion layer 121c does not react with oxygen. 2 / day or more 50000cc / m 2 It is preferable to use a polymer for the ion-electron conversion layer having an oxygen permeability of 0.05 cc / m 2 / day or more 10000cc / m 2 / day or less is more preferable, and 0.05cc / m 2 / day or more 5000cc / m 2 / day or less is even more preferable.

[0038] Furthermore, if the polymer for the ion-electron conversion layer has adhesive properties, the ion-electron conversion layer 121c can be used as an adhesive layer, which is preferable because it eliminates the need for a separate sealing member for pressing and sealing the working electrode 121a, the ion-electron conversion layer 121c, and the ion-responsive membrane 121b from the outside. Examples of such adhesive polymers include fluoropolysiloxane and polyvinyl alcohol.

[0039] From the viewpoint of preventing the carbon microstructures from dissolving into the ion-responsive membrane 121b, it is preferable that the polymer for the ion-electron conversion layer has solvent resistance such that it is difficult to dissolve in the solvent for the ion-responsive membrane after curing. Since an organic solvent may be used as the solvent for the ion-responsive membrane, it is preferable that the polymer for the ion-electron conversion layer has organic solvent resistance.

[0040] For example, when PVC is used as the polymer for the ion-responsive membrane, it is possible to use a solvent such as those listed here that gives a Q value of 2 or more. Therefore, it is preferable to use a polymer for the ion-electron conversion layer that is poorly soluble in the solvents listed here, for example, one with a Q value of less than 2. For example, when THF is used as the solvent for the ion-responsive membrane, it is preferable to use polyvinyl alcohol, which is hardly soluble in this solvent for the ion-responsive membrane, as the polymer for the ion-electron conversion layer.

[0041] In this embodiment, fluoropolysiloxane is used as an example of a polymer for the ion-electron conversion layer that has suitable properties in all of the various aspects described above.

[0042] The content of the polymer in the ion-electron conversion layer 121c is, for example, preferably 90% by mass or more and 99% by mass or less, and more preferably 95% by mass or more and 99% by mass or less.

[0043] The ion selective electrode 121 and the sensor unit 1 according to this embodiment are manufactured as follows. The working electrode 121 a is disposed so as to be electrically connected to a printed wiring P printed on the base material 11 .

[0044] Next, the polymer for the ion-electron conversion layer was dissolved in the solvent for the ion-electron conversion layer, and the carbon microstructures were suspended in the solution to prepare a coating liquid. This coating liquid was applied to cover the entire surface of the working electrode 121a on the sample solution side, and then dried and cured to form the ion-electron conversion layer 121c. At this time, the solvent for the ion-electron conversion layer may be completely evaporated, or a portion of the solvent may remain in the ion-electron conversion layer 121c to the extent that the function of the ion-electron conversion layer 121c is not impaired. Note that the above-mentioned contents of the carbon microstructures and the polymer for the ion-electron conversion layer are the contents in the ion-electron conversion layer 121c after curing.

[0045] After the ion-electron conversion layer 121c is completely hardened, the coating liquid for the ion-responsive membrane as described above is applied to cover the entire surface of the ion-electron conversion layer 121c on the sample solution side, and then dried and hardened to form the ion-responsive membrane 121b.

[0046] In this embodiment, since fluoropolysiloxane is used as the polymer for the ion-electron conversion layer, the ion-electron conversion layer 121c itself has adhesiveness. Therefore, the ion-electron conversion layer 121c acts as an adhesive to fix the working electrode 121a to the base material 11. The ion-responsive membrane 121b is also fixed to the ion-electron conversion layer 121c by the adhesiveness of the ion-electron conversion layer 121c.

[0047] Next, for example, the comparison electrode 122a is disposed so as to be in electrical contact with the printed wiring P printed on the base material 11, and the salt bridge layer 122b is attached to the base material 11 so as to cover the entire comparison electrode 122a. In this embodiment, the salt bridge layer 122b itself has adhesive properties, so that the comparison electrode 122 can be easily constructed by attaching the salt bridge layer 122b in this manner.

[0048] In the ion-selective electrode 121 and sensor unit 1 configured in this manner, the ion-electron conversion layer 121c contains the polymer for the ion-electron conversion layer, so the ion-electron conversion substance in the ion-electron conversion layer 121c is protected by the polymer for the ion-electron conversion layer and is therefore less likely to elute, which makes it possible to prevent the ion-electron conversion substance from being mixed into the ion-responsive membrane 121b.

[0049] Furthermore, because tetrahydrofuran is used as the solvent for the ion-responsive membrane and fluoropolysiloxane is used as the polymer for the ion-electron conversion layer, the fluoropolysiloxane is not easily dissolved even if a coating agent for the ion-responsive membrane containing tetrahydrofuran is applied after the ion-electron conversion layer 121c is cured. As a result, it is possible to further prevent the ion-electron conversion material from eluting from the ion-electron conversion layer 121c and contaminating the ion-responsive membrane 121b.

[0050] The present invention is not limited to the above-described embodiment. For example, in the above embodiment, the ion-responsive membrane contains 4-tert-butylcalix[4]arene-tetraacetic acid as the ion-responsive substance. tetraethyl esterHowever, other ion-responsive substances such as valinomycin or neutral carriers may be used as the ion-responsive substance, and various types of ion-responsive membranes that respond not only to sodium ions but also to other ions such as potassium ions and calcium ions may be used. The ion-responsive membrane is preferably a polymer type that contains a polymer.

[0051] In addition to the above-mentioned PVC, the polymer for the ion-responsive membrane may be, for example, polystyrene, acrylate, methacrylate, polyvinyl butyral, polyamide, polyimide, polyurethane, polytetrafluoroethylene (PTFE), polysiloxane, copolymer of vinylidene fluoride and hexafluoropropylene (PVDH-HFP), etc., but is not limited to these.

[0052] The polymer for the ion-electron conversion layer is not limited to those mentioned above, and it is preferable to change it appropriately according to the type of the solvent for the ion-responsive membrane used when preparing the ion-responsive membrane.

[0053] In the above embodiment, the ion-electron conversion layer functions as an adhesive, and therefore no separate sealing member is provided to fix and seal the working electrode, the ion-electron conversion layer, and the ion response membrane to the substrate. However, in cases where the ion-electron conversion layer does not have adhesive properties, a separate sealing member may be provided to fix and seal the working electrode, the ion-electron conversion layer, and the ion response membrane to the substrate.

[0054] In addition, the ion-electron conversion layer has adhesive properties. There are Even in this case, the sealing member may be provided to further reduce the risk of direct contact between the sample solution and the working electrode or the ion-electron conversion layer, which may cause fluctuations in the measured values.

[0055] The reference electrode is not limited to the one having the salt bridge layer as described above. In this case, a differential ion concentration measuring device can be provided in which the comparison electrode directly contacts the sample solution without a salt bridge layer. In such an ion concentration measuring device, the reference electrode does not have a salt bridge layer, so the sensor unit can be made smaller. In such a differential ion concentration measuring device, the potential of the comparison electrode is not constant but may fluctuate. However, if the ion selective electrode 121 is provided with a sodium ion selective electrode 121Na and a potassium ion selective electrode 121K as shown in FIG. 5, the concentration ratio of sodium ions to potassium ions can be directly determined without determining the concentration of each ion by measuring the potential differences between each of the ion selective electrodes 121Na and 121K and the comparison electrode 122. The concentration ratio of sodium ions to potassium ions measured by this differential ion concentration measuring device can be determined, for example, as follows. First, the sodium ion selective electrode 121Na and the potassium ion selective electrode 121K ion An appropriate amount of sample solution is dropped so that the response membrane and the comparison electrode of the comparison electrode 122 come into contact with the sample solution. Then, the sodium ion selective electrode 121Na Ion Response Membrane and potassium ion selective electrode 121K Ion Response An electromotive force corresponding to the concentration of each ion is generated in the membrane. This electromotive force is detected as a potential difference (voltage) between the working electrode of the sodium ion selective electrode 121Na or the working electrode of the potassium ion selective electrode 121K and the comparison electrode of the comparison electrode 122. Next, the concentration ratio of sodium ions to potassium ions can be determined using these potential differences. A practical method for calculating the concentration ratio of sodium ions to potassium ions in a sample solution is as follows: The potential difference between the sodium ion selective electrode 121Na or the potassium ion selective electrode 121K and the reference electrode 122 in a standard solution in which the concentration ratio of sodium ions to potassium ions is known is determined, and then the potential difference between the sodium ion selective electrode 121Na or the potassium ion selective electrode 121K and the reference electrode 122 in the sample solution is determined. The concentration ratio of sodium ions to potassium ions in the sample can be calculated using the concentration ratio of sodium ions to potassium ions in the standard solution, the potential differences in the standard solution, and the potential differences in the sample.

[0056] In the above-described embodiment, an example was described in which the ion-electron conversion layer contains an ion-electron conversion material and a polymer for the ion-electron conversion layer, but this is not limited thereto, and the ion-electron conversion layer may be formed, for example, from a conductive polymer having ion-electron conversion function. Specific examples of the conductive polymer include poly(3,4-ethylenedioxythiophene) (PEDOT), poly(p-phenylene sulfide) (PSS), poly(thiophene)s (PT), polyanilines (PANI), polypyrrole (PPY), etc. Any one of these conductive polymers may be used alone, or a suitable mixture of two or more types may be used, such as a mixture of PEDOT and PSS (PEDOT:PSS=1:2). Furthermore, the ion-electron conversion layer may contain the conductive polymer and the ion-electron conversion material. Various modifications and combinations of the embodiments may be made as long as they do not deviate from the spirit of the present invention. [Example]

[0057] In this example, the sodium ion concentration was measured using the sensor unit described in the above embodiment. As a comparative example, the sodium ion concentration was measured using the same sensor unit as in the example except that the ion-electron conversion layer did not contain a polymer, and the results of this example and comparative example were compared.

[0058] The specific experimental method is as follows. The sensor unit was immersed in samples with different sodium ion contents every 180 seconds, and the change in potential over time was measured. The results are shown in Figure 4. The experiment was performed three times in duplicate for each of the example and comparative example.

[0059] In the comparative example shown by the dashed line, it can be seen that the values ​​fluctuate each time the sodium ion concentration of the sample is changed. Furthermore, when comparing the results of two experiments using the same sensor unit, it can be seen that the measured values ​​vary from one run to the next and that reproducibility is poor.

[0060] In contrast, in the example shown by the solid line, the deviation in the measured values ​​is clearly smaller than in the comparative example shown by the dashed line, and the results of the duplicate measurements almost overlap. Furthermore, it can be seen that even if the sample concentration is changed many times, the measured values ​​are almost the same each time for samples of the same concentration.

[0061] From these results, it was found that by incorporating a polymer into the ion-electron conversion layer, drift in the measured values ​​can be suppressed and reproducibility can be improved. [Industrial Applicability]

[0062] It is possible to provide an all-solid-state ion-selective electrode that can provide more stable measurements.

Claims

1. An all-solid-state ion-selective electrode comprising a working electrode and an ion-responsive membrane, an ion-electron conversion layer disposed between the working electrode and the ion-responsive membrane to electrically connect them; the ion-electron conversion layer contains an ion-electron conversion material and a polymer; An all-solid-state ion-selective electrode, wherein the polymer is resistant to the solvent used in producing the ion-responsive membrane.

2. 2. The all-solid-state ion-selective electrode according to claim 1, wherein the entire surface of the ion-electron conversion layer facing the sample solution is covered with the ion-responsive membrane.

3. 3. The all-solid-state ion-selective electrode according to claim 1, wherein the ion-electron conversion material contains one or more materials selected from the group consisting of carbon nanotubes, graphene, and graphite.

4. The oxygen permeability of the polymer is 0.05 cc / m ２ / day or more 50000cc / m ２ 4. The all-solid-state ion-selective electrode according to claim 1, wherein the ion-selective capacity is 1000 kJ / day or less.

5. 5. An all-solid-state ion-selective electrode according to any one of claims 1 to 4, wherein the polymer is a fluoropolysiloxane.

6. An all-solid-state ion-selective electrode according to any one of claims 1 to 5; and a reference electrode.

7. the all-solid-state ion-selective electrodes are sodium ion-selective electrodes and potassium ion-selective electrodes; the reference electrode is used in common with both the sodium ion selective electrode and the potassium ion selective electrode, 7. The ion concentration measuring device according to claim 6, wherein the reference electrode does not include a salt bridge layer.

8. A method for manufacturing an all-solid-state ion-selective electrode including a working electrode and an ion-responsive membrane, comprising: forming an ion-electron conversion layer on the surface of the working electrode, the layer electrically connecting the working electrode and the ion-responsive membrane; the ion-electron conversion layer contains an ion-electron conversion material and a polymer; A method for producing an all-solid-state ion-selective electrode, wherein the polymer is resistant to a solvent used in producing the ion-responsive membrane.

9. forming an ion-responsive membrane on the surface of the ion-electron conversion layer on the sample solution side, 9. The method for producing an all-solid-state ion-selective electrode according to claim 8, wherein the polymer contained in the ion-electron conversion layer is resistant to a solvent used in forming the ion-responsive membrane.

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