Ion selective electrode

Abstract

A fully solid-state ion-selective electrode is provided, which enables more stable measurement values. This fully solid-state ion-selective electrode is characterized by having a working electrode and an ion-response membrane, and having an ion-electron conversion layer disposed between the working electrode and the ion-response membrane, electrically connecting them. The ion-electron conversion layer contains an ion-electron conversion material and a polymer, or contains a polymer with ion-electron conversion functionality.

Description

Technical Field

[0001] This 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, an electrode is considered as described in Non-Patent Document 1, in which a layer consisting only of carbon nanotubes electrically connecting the working electrode to an ion-responsive membrane is provided on the surface of a working electrode made of metal, and an ion-responsive membrane is stacked on the sample solution side of the carbon nanotube layer.

[0003] Existing technical documents

[0004] Non-patent literature

[0005] Non-patent literature 1: “Ion-Selective Electrodes Using Carbon Nanotubes as Ion-to-Electron Transducers”, Gaston A. Crespo et al., Anal. Chem., 80, 1316-1322 (2008).

[0006] Non-Patent Literature 2: "Solubility parameters for determining optimal 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

[0007] Technical issues

[0008] However, when the ion concentration was actually measured using this conventional all-solid-state ion-selective electrode, the inventors noticed that the measured values ​​drifted.

[0009] The inventors carefully investigated the reasons for the drift in the measured values ​​and concluded that the cause might be the incorporation of carbon nanotubes into the ion-responsive membrane.

[0010] In the fabrication of conventional all-solid-state ion-selective electrodes, after forming the carbon nanotube layer, the material of the ion-responsive membrane is suspended in an organic solvent and then dropped onto the surface of the carbon nanotube layer. At this time, the carbon nanotubes constituting the carbon nanotube layer dissolve in the organic solvent contained in the ion-responsive membrane material, thus incorporating the carbon nanotubes into the ion-responsive membrane. If carbon nanotubes are thus incorporated into the ion-responsive membrane, it is assumed that the sample solution reacts directly with the carbon nanotubes incorporated into the ion-responsive membrane, thereby causing a drift in the measured value.

[0011] The present invention was made in view of the aforementioned problems, and its object is to provide an all-solid-state ion-selective electrode that can suppress the incorporation of carbon nanotube plasma ion-electron conversion materials into the ion-responsive membrane, thereby making the measured values ​​more stable.

[0012] Technical solution

[0013] That is, the all-solid-state ion-selective electrode of the present invention is characterized by having a working electrode and an ion-response membrane, and having an ion-electron conversion layer disposed between the working electrode and the ion-response 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.

[0014] According to this all-solid-state ion-selective electrode, since the ion-electron conversion layer contains a polymer, the ion-electron conversion material in the ion-electron conversion layer is protected by the polymer and is not easily dissolved. As a result, it is possible to suppress the mixing of ion-electron conversion material into the ion-responsive membrane.

[0015] If the entire surface of the ion-electron conversion layer on the sample solution side is covered by the ion-responsive membrane, then no additional sealing component is required to prevent the ion-electron conversion material in the ion-electron conversion layer from directly contacting the sample solution.

[0016] As a specific embodiment of the present invention, the ion-electron conversion material may include one or more of the group consisting of carbon nanotubes, graphene, and graphite.

[0017] If the polymer is adhesive, the ion-electron conversion layer also functions as an adhesive layer. Therefore, an all-solid-state ion-selective electrode can be fabricated simply by stacking the ion-electron conversion layer on the working electrode and then stacking the ion-responsive film on top of the ion-electron conversion layer.

[0018] When carbon microstructures, such as carbon nanotubes, are used as the ion-electron conversion material, the adsorption of oxygen by these microstructures alters the properties of the ion-electron conversion material. Therefore, it is preferable that the polymer has an oxygen permeability of 0.05 cc / m. 2 / day or more and 50,000cc / m 2 / day or less.

[0019] Furthermore, if the polymer is an oxygen-impermeable polymer, then the polymer used in the ion-responsive membrane does not need to be a polymer with low oxygen permeability, which can expand the range of raw materials that can be selected for the ion-responsive membrane.

[0020] If the polymer is resistant to the solvent used in manufacturing the ion-responsive membrane, the dissolution of the ion-electron conversion layer in the solvent can be suppressed. This results in further suppression of the ion-electron conversion material or polymer with ion-electron conversion functionality from the ion-electron conversion layer.

[0021] As a specific embodiment of the present invention, the polymer can be listed as fluoropolysiloxane.

[0022] Technical effect

[0023] According to the present invention, the measured values ​​of the all-solid-state ion-selective electrode are more stable than ever before. Attached Figure Description

[0024] Figure 1 This is a schematic diagram showing the overall structure of an ion concentration measuring device according to one embodiment of the present invention.

[0025] Figure 2 This is a schematic diagram illustrating a sensor unit according to one embodiment of the present invention.

[0026] Figure 3 This is a schematic diagram showing the cross-section of the ion-selective electrode and the reference electrode in this embodiment.

[0027] Figure 4 The graph shows the sodium ion determination results using the ion-selective electrodes of the embodiments and comparative examples of the present invention.

[0028] Figure 5 This is a schematic diagram of the sensor unit of an ion concentration measuring device according to another embodiment of the present invention.

[0029] Symbol Explanation

[0030] 100: Ion Concentration Measuring Device

[0031] 1: Sensor Unit

[0032] 121: Ion-selective electrode

[0033] 121a: Working pole

[0034] 121b: Ion-responsive membrane

[0035] 121c: Ion-electron conversion layer

[0036] 122: Reference electrode Detailed Implementation

[0037] Hereinafter, an embodiment of the present invention will be described using the accompanying drawings.

[0038] The ion concentration measuring device 100 of this embodiment is, for example, as shown in the example... Figure 1 As shown, the device includes: a sensor unit 1 that contacts a sample solution to detect ions or the like contained in the sample solution; a calculation unit 2 that calculates ion concentration or the like based on the output value output from the sensor unit 1; a display unit 3 that displays the measured values ​​or the like calculated by the calculation unit 2; and a control unit 4 that controls the calculation unit 2 and the display unit 3.

[0039] The aforementioned sensor unit 1 is, for example, as follows: Figure 2 As shown, it includes: a film-like substrate 11 made of liquid crystal polymer, polyvinyl chloride or polyethylene terephthalate, etc., with a length of 3cm, a width of 1cm and a thickness of about 0.5mm, and an electrode portion 12 disposed on the substrate 11.

[0040] In this embodiment, the function of the computing unit 2 is performed by the information processing circuit 5, which is separate from the sensor unit 1.

[0041] The information processing circuit 5 includes: digital circuits consisting of a CPU, memory, communication ports, etc.; analog circuits including buffers and amplifiers; and AD converters, DA converters, etc., which act as intermediaries between these digital and analog circuits. Furthermore, the CPU and / or its peripheral devices cooperate according to a predetermined program stored in the aforementioned memory, thereby enabling the information processing circuit 5 to function as the aforementioned computing unit 2.

[0042] The electrode section 12 described above will now be described in detail.

[0043] The electrode section 12 described above is, for example, Figure 2 As shown, it includes an ion-selective electrode 121 and a reference electrode 122 that are respectively connected to the information processing circuit 5 via printed wiring P formed on the substrate 11.

[0044] In this embodiment, the ion-selective electrode 121 is, for example, a sodium ion-selective electrode for measuring the sodium ion concentration of a sample solution.

[0045] The aforementioned ion-selective electrode 121 is an all-solid-state electrode, such as... Figure 3 As shown in (a), it includes: a flat working electrode 121a disposed on a substrate 11 in a manner that is electrically connected to the printed wiring P, an ion-responsive film 121b formed to cover the working electrode 121a, and an ion-electron conversion layer 121c disposed between the working electrode 121a and the ion-responsive film 121b.

[0046] The aforementioned working electrode 121a is, for example, a metal such as silver or platinum.

[0047] The aforementioned ion-responsive membrane 121b is formed by covering the aforementioned ion-electron conversion layer 121c, and contains an ion-responsive material and a polymer (polymer for ion-responsive membranes).

[0048] In this embodiment, as an example, an ion-responsive membrane containing 4-tert-Butylcalix[4]arene-tetraacetic acid tetraethyl ester as the above-mentioned ion-responsive material and polyvinyl chloride (hereinafter also referred to as PVC) as the above-mentioned ion-responsive membrane polymer will be described.

[0049] The aforementioned ion-responsive membrane 121b is formed by coating the aforementioned ion-electron conversion layer 121c with a substance obtained by dissolving the aforementioned ion-responsive material and the aforementioned ion-responsive membrane polymer in a suitable solvent (ion-responsive membrane solvent), and then drying and curing it. In this embodiment, as an example of the aforementioned ion-responsive membrane solvent, tetrahydrofuran, an organic solvent that easily dissolves PVC, which is used as the aforementioned ion-responsive membrane polymer, is used.

[0050] Regarding whether a solvent is one that readily dissolves a polymer, this specification uses, for example, the following mathematical formula 1.

[0051] [Mathematical Expression 1]

[0052]

[0053] (In mathematical formula 1, m1 represents the mass of the test piece before the experiment, m2 represents the mass of the test piece after the experiment, p1 represents the density of the polymer in the test piece, and p2 represents the density of the solvent.)

[0054] The above Q is calculated based on the change in mass of the test piece when 0.2g of the test piece is immersed in 5ml of solvent at 20°C for 30 minutes.

[0055] Regarding whether a polymer is easily soluble, if the value of Q is 2 or higher, it is considered easily soluble; if the value of Q is 10 or higher, it is considered very easily soluble.

[0056] Therefore, as the solvent for the above-mentioned ion-responsive membrane, it is preferable to use a solvent in which the value of Q calculated using a test piece made of PVC is 2 or more, and more preferably a solvent in which the value of Q is 10 or more.

[0057] Regarding PVC, examples of solvents with a Q value of 10 or higher include tetrahydrofuran, cyclohexanone, cyclopentanone, dimethylacetamide (DMA), pyridine, 3-pentanone, 2-pentanone, dimethylformamide (DMF), and methyl ethyl ketone (MEK).

[0058] Regarding PVC, examples of solvents with a Q value of 2 or higher include dichloromethane, 4-methylpentan-2-one, nitrobenzene, 1,4-dioxane, 1,1,2,2-tetrachloroethane, acetone, ethyl acetate, chloroform, etc.

[0059] The aforementioned reference electrode 122 functions as a reference electrode for the aforementioned ion-selective electrode 121, such as... Figure 3 As shown in (b), it includes: a flat comparator 122a disposed on the substrate 11 in a manner that is electrically connected to the printed wiring P, and a salt bridge layer 122b mounted to cover the comparator 122a.

[0060] The aforementioned comparative electrode 122a is preferably a metal that is difficult to be oxidized, and specific examples include silver / silver chloride electrode, silver electrode or carbon electrode.

[0061] The aforementioned salt bridge layer 122b is a layer that electrically connects the aforementioned comparator 122a to the sample solution, and is, for example, a gel-like internal liquid.

[0062] Then, the aforementioned ion-electron conversion layer 121c contains, for example, an ion-electron conversion material and a polymer (polymer for ion-electron conversion layer).

[0063] As the aforementioned ion-electron conversion material, carbon microstructures, for example, can be used.

[0064] As the aforementioned carbon microstructures, one or more carbon microstructures selected from, for example, carbon nanotubes, carbon nanofibers, carbon nanowalls, fullerenes, graphite, and graphene can be used. In this embodiment, carbon nanotubes are used as an example of the aforementioned ion-electron conversion material.

[0065] The content of the aforementioned carbon microstructures in the aforementioned ion-electron conversion layer 121c is preferably 0.001% by mass or more and 12.0% by mass or less, more preferably 0.001% by mass or more and 0.02% by mass or less, and even more preferably 0.003% by mass or more and 0.01% by mass or less.

[0066] The polymer used for the aforementioned ion-electron conversion material is not particularly limited; for example, it can be a natural resin or a synthetic resin.

[0067] The aforementioned natural resin can be any one of the following: natural resin derived from plants, natural resin derived from animals, or natural resin derived from minerals.

[0068] As the aforementioned synthetic resins, a wide range of synthetic resins can be used, including, for example, polyvinyl chloride (PVC), polystyrene, polyvinyl butyral, polyamide resins, polyimide resins, polyurethane resins, PTFE, silicone resins, polyvinylidene fluoride-hexafluoropropylene copolymer, acrylic resins, epoxy resins, polyolefins, and raw rubber. Examples of silicone resins include, for example, fluorinated polysiloxanes, polydimethylsiloxanes, and polysiloxanes. Examples of acrylic resins include, for example, polyacrylates, polymethacrylates, and polybutyl acrylates. Examples of polyamide resins include, for example, polyamides, aliphatic polyamides, and polyphthalamides. Examples of polyimide resins include, for example, aliphatic polyimides and aromatic polyimides. Examples of polyurethane resins include, for example, glycol-based polyurethanes and amino-based polyurethanes.

[0069] The polymer used for the aforementioned ion-electron conversion layer preferably has an oxygen permeability of 0.05 cc / m. 2 / day or more and 50,000cc / m 2 The polymer used in the ion-electron conversion layer is selected to have a permeability of less than 0.05 cc / m², to prevent the ion-electron conversion material in the ion-electron conversion layer 121c from reacting with oxygen. The oxygen permeability of the polymer used in the ion-electron conversion layer is more preferably 0.05 cc / m². 2 / day or more and 10000cc / m 2 Below / day, further preferably 0.05cc / m 2 / day or more and 5000cc / m 2 / day or less.

[0070] Furthermore, if the polymer used for the ion-electron conversion layer has adhesive properties, the ion-electron conversion layer 121c can be used as an adhesive layer. Therefore, it is not necessary to prepare a separate sealing component to press and seal the working electrode 121a, the ion-electron conversion layer 121c, and the ion-responsive membrane 121b from the outside, which is preferred. Examples of such adhesive polymers include fluoropolysiloxanes or polyvinyl alcohol.

[0071] From the viewpoint of suppressing the dissolution of the aforementioned carbon microstructures in the aforementioned ion-responsive membrane 121b, it is preferable that the polymer for the aforementioned ion-electron conversion layer is a solvent-resistant polymer that is not easily dissolved in the solvent for the aforementioned ion-responsive membrane after curing. Since the solvent for the aforementioned ion-responsive membrane may be an organic solvent, the polymer for the aforementioned ion-electron conversion layer preferably has organic solvent resistance.

[0072] For example, when using PVC as the polymer for the aforementioned ion-responsive membrane, it is advisable to use solvents with a Q value of 2 or higher, as listed herein. Therefore, as the polymer for the aforementioned ion-electron conversion layer, it is preferable to use a polymer that is not easily soluble in the solvents listed herein, for example, a polymer with a Q value of less than 2.

[0073] For example, when using THF as the solvent for the ion-responsive membrane, it is preferable to use polyvinyl alcohol, which is not easily soluble in the solvent for the ion-responsive membrane, as the polymer for the ion-electron conversion layer.

[0074] In this embodiment, fluoropolysiloxane is used as an example of the polymer for the ion-electron conversion layer that has suitable properties among all the various views described above.

[0075] The content of the polymer in the ion-electron conversion layer 121c is preferably set to 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.

[0076] The manufacturing method of the ion-selective electrode 121 and the sensor unit 1 described in this embodiment is as follows.

[0077] The working electrode 121a is configured to be electrically connected to the printed wiring P printed on the substrate 11.

[0078] Next, the polymer for the ion-electron conversion layer is dissolved in the solvent for the ion-electron conversion layer to prepare a coating solution in which the carbon microstructures are suspended. The coating solution is applied to cover the entire surface of the sample solution side of the working electrode 121a, and then dried and cured to form the ion-electron conversion layer 121c.

[0079] At this point, the solvent used in the aforementioned ion-electron conversion layer can either completely evaporate or remain partially in the aforementioned ion-electron conversion layer 121c to a degree that does not impair its function. It should be noted that the aforementioned content of the carbon microstructures and / or the polymer used in the aforementioned ion-electron conversion layer refers to the content in the cured ion-electron conversion layer 121c.

[0080] After the ion-electron conversion layer 121c is completely cured, a coating liquid for an ion-responsive membrane is applied to cover the entire surface of the sample solution side of the ion-electron conversion layer 121c, and then dried and cured to form an ion-responsive membrane 121b.

[0081] In this embodiment, since fluoropolysiloxane is used as the polymer for the ion-electron conversion layer, the ion-electron conversion layer 121c itself has adhesive properties. Therefore, the ion-electron conversion layer 121c functions as an adhesive to fix the working electrode 121a to the substrate 11. Furthermore, the ion-responsive membrane 121b is also fixed to the ion-electron conversion layer 121c by the adhesive properties of the ion-electron conversion layer 121c.

[0082] Next, for example, the comparator 122a is configured to make electrical contact with the printed wiring P printed on the substrate 11, and the salt bridge layer 122b is mounted on the substrate 11 to cover the entire comparator 122a. In this embodiment, since the salt bridge layer 122b itself is adhesive, the reference electrode 122 can be easily constructed by mounting the salt bridge layer 122b in this way.

[0083] Based on the ion-selective electrode 121 and sensor unit 1 configured as described above, since the ion-electron conversion layer 121c contains the polymer used for the ion-electron conversion layer, the ion-electron conversion material in the ion-electron conversion layer 121c is protected by the polymer and is not easily dissolved. As a result, it is possible to suppress the mixing of ion-electron conversion material into the ion-responsive membrane 121b.

[0084] Furthermore, since 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 when a coating agent containing tetrahydrofuran is applied to the ion-responsive membrane after the ion-electron conversion layer 121c has been cured. As a result, the ion-electron conversion material can be further suppressed from dissolving from the ion-electron conversion layer 121c and mixing into the ion-responsive membrane 121b.

[0085] The present invention is not limited to the embodiments described above.

[0086] For example, although the above embodiment describes the ion-responsive membrane as an example of a Na+ responsive membrane containing 4-tert-Butylcalix[4]arene-tetraacetic acid tetraethyl ester as the ion-responsive material, other ion-responsive materials such as valacyclovir or a neutral carrier can also be used as the ion-responsive material, and various ion-responsive membranes that respond not only to sodium ions but also to other ions such as potassium ions and / or calcium ions can also be used. The above-described ion-responsive membrane is preferably a polymer-type ion-responsive membrane containing a polymer.

[0087] In addition to PVC, other polymers used for the aforementioned ion-responsive membranes include, but are not limited to, polystyrene, acrylates, methacrylates, polyvinyl butyral, polyamides, polyimides, polyurethanes, polytetrafluoroethylene (PTFE), polysiloxanes, copolymers of vinylidene fluoride and hexafluoropropylene (PVDH-HFP).

[0088] The polymer used in the ion-electron conversion layer is not limited to the polymers described above, and is preferably modified appropriately to match the type of solvent used in the fabrication of the ion-responsive membrane.

[0089] In the above embodiments, since the ion-electron conversion layer functions as an adhesive, no additional sealing member is provided to fix and seal the working electrode, the ion-electron conversion layer, and the ion-response film relative to the substrate. However, if the ion-electron conversion layer does not have adhesive properties, a sealing member may be provided to fix and seal the working electrode, the ion-electron conversion layer, and the ion-response film relative to the substrate.

[0090] Furthermore, even if the aforementioned ion-electron conversion layer is adhesive, the aforementioned sealing component can be provided to further reduce the possibility of deviation in the measured value caused by direct contact between the sample solution and the aforementioned working electrode and the aforementioned ion-electron conversion layer.

[0091] The reference electrode described above is not limited to the electrode with a salt bridge layer as described above.

[0092] In this case, it is possible to configure a differential ion concentration measuring device in which the comparison electrode is in direct contact with the sample solution without being separated by a salt bridge layer. If such an ion concentration measuring device is configured, the sensor unit can be further miniaturized since the reference electrode does not have a salt bridge layer.

[0093] In such a differential ion concentration measuring device, the potential of the aforementioned comparison electrode may not be constant, but rather variable, but if... Figure 5 As shown, if the ion-selective electrode 121 is equipped with a sodium ion-selective electrode 121Na and a potassium ion-selective electrode 121K, then by measuring the potential difference between each of these ion-selective electrodes 121Na, 121K and the reference electrode 122, the concentration ratio of sodium ions to potassium ions can be directly determined without determining the concentration of each ion.

[0094] The concentration ratio of sodium ions to potassium ions obtained based on this differential ion concentration measuring device can be determined, for example, in the following manner.

[0095] First, an appropriate amount of sample solution is dripped into the sample solution by contacting the response membranes of the sodium ion selective electrode 121Na and the potassium ion selective electrode 121K with the comparison electrode of the reference electrode 122.

[0096] Therefore, an electromotive force corresponding to the concentration of each ion is generated in the response membrane of the sodium ion selective electrode 121Na and the potassium ion selective electrode 121K.

[0097] This electromotive force is detected as the 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 reference electrode 122. Then, the concentration ratio of sodium ions to potassium ions can be determined using their potential difference.

[0098] A practical method for calculating the concentration ratio of sodium ions to potassium ions in a sample solution is described below. First, determine the potential differences between the sodium ion selective electrode 121Na or the potassium ion selective electrode 121K and the reference electrode 122 in a standard solution where the sodium ion to potassium ion concentration ratio is known. Then, determine the potential differences between the sodium ion selective electrode 121Na or the potassium ion selective electrode 121K and the reference electrode 122 in the sample solution. Using the sodium ion to potassium ion concentration ratio of the standard solution, the potential differences in the standard solution, and the potential differences in the sample, the concentration ratio of sodium ions to potassium ions in the sample can be calculated.

[0099] In the above embodiments, examples of ion-electron conversion layers containing ion-electron conversion materials and polymers for ion-electron conversion layers have been described, but the embodiments are not limited thereto. For example, the ion-electron conversion layer may also be formed from a conductive polymer having ion-electron conversion function.

[0100] Specific examples of the aforementioned conductive polymers include poly(3,4-ethylenedioxythiophene) (PEDOT), poly(p-phenylene sulfide) (PSS), poly(thiophene)s (PT), polyaniline (PANI), and polypyrrole (PPY). Any of these conductive polymers can be used alone, or multiple types can be appropriately mixed, for example, as in a mixture of PEDOT and PSS (PEDOT:PSS = 1:2).

[0101] Furthermore, the aforementioned ion-electron conversion layer may be an ion-electron conversion layer containing the aforementioned conductive polymer and the aforementioned ion-electron conversion material.

[0102] Various modifications and combinations of implementation methods are permissible as long as they do not violate the spirit of this invention.

[0103] Example

[0104] In this embodiment, the sensor unit described in the above embodiments is used to determine the sodium ion concentration. Furthermore, as a comparative example, the same sensor unit as in the embodiments is used to determine the sodium ion concentration, except that it does not contain a polymer in the ion-electron conversion layer. The results from these embodiments and comparative examples are compared and studied.

[0105] The specific experimental methods are as follows.

[0106] The sensor unit was immersed in samples with different sodium ion concentrations every 180 seconds, and the potential change over time was measured. The results are presented below. Figure 4 In the examples and comparative examples, experiments were conducted in duplicate, with three experiments performed on each duplicate.

[0107] As can be seen in the comparative example shown by the dashed line, the values ​​deviated whenever the sodium ion concentration of the sample was changed. Furthermore, comparing the results of two experiments using the same sensor unit reveals that the measurements are quite dispersed and have low repeatability.

[0108] In contrast, the results of the example shown by the solid line show a significantly smaller deviation in the measured values ​​compared to the results of the comparative example shown by the dashed line, and the two sets of measured results almost overlap. Furthermore, it is evident that even when the sample concentration is changed multiple times, the measured values ​​are almost identical each time for samples of the same concentration.

[0109] The results show that by including polymers in the ion-electron conversion layer, drift in the measured values ​​can be suppressed, and reproducibility can also be improved.

[0110] Industrial availability

[0111] It can provide an all-solid-state ion-selective electrode that can make the measured values ​​more stable.

Claims

1. An all-solid-state ion-selective electrode, characterized in that, It has a working electrode and an ion-responsive membrane. The all-solid-state ion-selective electrode includes an ion-electron conversion layer disposed between the working electrode and the ion-responsive membrane, electrically connecting them. The ion-electron conversion layer contains ion-electron conversion materials and polymers, or contains polymers with ion-electron conversion functions. The polymer is resistant to the solvents used in manufacturing the ion-responsive membrane.

2. The all-solid-state ion-selective electrode according to claim 1, characterized in that, The entire sample solution side of the ion-electron conversion layer is covered by the ion-responsive membrane.

3. The all-solid-state ion-selective electrode according to claim 1 or 2, characterized in that, The ion-electron conversion material contains one or more of the following groups: carbon nanotubes, graphene, and graphite.

4. The all-solid-state ion-selective electrode according to claim 1 or 2, characterized in that, The polymer has adhesive properties.

5. The all-solid-state ion-selective electrode according to claim 1 or 2, characterized in that, The oxygen permeability of the polymer is 0.05 cc / m 2 / day or more and 50,000cc / m 2 / day or less.

6. The all-solid-state ion-selective electrode according to claim 1 or 2, characterized in that, The polymer is a fluoropolysiloxane.

7. An ion concentration measuring device, characterized in that, have: The all-solid-state ion-selective electrode according to any one of claims 1 to 6; and Reference electrode.

8. The ion concentration measuring device according to claim 7, characterized in that, The all-solid-state ion-selective electrode is a sodium ion-selective electrode and a potassium ion-selective electrode. The reference electrode is used in conjunction with both the sodium ion selective electrode and the potassium ion selective electrode. The reference electrode does not have a salt bridge layer.

9. A method for manufacturing an all-solid-state ion-selective electrode, characterized in that, The all-solid-state ion-selective electrode has a working electrode and an ion-responsive membrane. The manufacturing method includes a step of forming an ion-electron conversion layer on the surface of the working electrode that electrically connects the working electrode to the ion-responsive membrane. The ion-electron conversion layer contains ion-electron conversion materials and polymers, or contains polymers with ion-electron conversion functions. The manufacturing method includes the step of forming an ion-responsive film on the sample solution side of the ion-electron conversion layer. The polymer contained in the ion-electron conversion layer is resistant to the solvents used in forming the ion-responsive membrane.

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