Composition for all-solid-state ion-selective electrode

Abstract

To provide an all-solid-state ion-selective electrode that has structural strength and exhibits excellent measurement accuracy and potential stability.SOLUTION: The composition for an all-solid-state ion-selective electrode used in an insertion member for the all-solid-state ion-selective electrode contains a water-absorbing resin.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a composition for an all-solid-state ion-selective electrode.

Background Art

[0002] Ion-selective electrodes are used to measure ion concentrations related to various measurement targets such as in water and soil. As ion-selective electrodes, liquid membrane type ion-selective electrodes have been conventionally preferred from the viewpoint of being able to maintain high measurement accuracy. However, it has been difficult to miniaturize them, and the ion-selective response member in contact with the measurement target has a membrane structure that separates the measurement target and the internal solution of the liquid, so it has been physically easily damaged. Therefore, it is difficult to use solid soil as a measurement target.

[0003]

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional all-solid-state ion-selective electrode shown in Patent Document 1, the potential stability and measurement accuracy are still low compared to the liquid membrane type ion-selective electrode.

[0005] The present invention aims to solve the above problems and provides an all-solid-state ion-selective electrode having structural strength and excellent measurement accuracy and potential stability.

Means for Solving the Problems

[0006] ​As a result of intensive studies to solve the above problems, the present inventors have found that a composition containing a water-absorbing resin, particularly a polyvinyl butyral resin, can provide an all-solid-state ion-selective electrode capable of solving the above problems. That is, the present invention includes the following aspects.

[0007] Item 1. An all-solid-state ion-selective electrode composition for an insertion member for an all-solid-state ion-selective electrode, comprising: An all-solid-state ion-selective electrode composition containing a water-absorbing resin.

[0008] Item 2. The all-solid-state ion-selective electrode composition according to Item 1, wherein the water-absorbing resin is a polyvinyl butyral resin.

[0009] Item 3. The all-solid-state ion-selective electrode composition according to Item 1 or 2, further containing an electrolyte containing an ion species to be measured.

[0010] Item 4. The all-solid-state ion-selective electrode composition according to Item 3, wherein the ion species is at least one selected from the group consisting of an alkali metal ion, an alkaline earth metal ion, a heavy metal ion, an ammonium ion, a nitrate ion, a perchlorate ion, and a chloride ion.

[0011] Item 5. An insertion member for an all-solid-state ion-selective electrode containing a water-absorbing resin.

[0012] Item 6. The insertion member for an all-solid-state ion-selective electrode according to Item 5, wherein the water-absorbing resin is a polyvinyl butyral resin.

[0013] Item 7. The insertion member for an all-solid-state ion-selective electrode according to Item 5 or 6, further containing an electrolyte containing an ion species to be measured.

[0014] Item 8. The insertion member for an all-solid-state ion-selective electrode according to item 7, wherein the ion species is at least one selected from the group consisting of alkali metal ions, alkaline earth metal ions, heavy metal ions, ammonium ions, nitrate ions, perchlorate ions, and chloride ions.

[0015] Item 9. An all-solid-state ion-selective electrode comprising the insertion member for an all-solid-state ion-selective electrode according to any one of items 4 to 8.

[0016] Item 10. Further comprising an internal reference electrode and an ion-selective sensing member, The all-solid-state ion-selective electrode according to item 9, wherein the internal reference electrode, the insertion member for an all-solid-state ion-selective electrode, and the ion-selective sensing member are electrically connected in this order.

[0017] Item 11. The all-solid-state ion-selective electrode according to item 10, wherein the ion-selective sensing member contains an electrolyte containing the ion species to be measured, a plasticizer, and a polymer for the ion-selective sensing member.

[0018] Item 12. The all-solid-state ion-selective electrode according to any one of items 9 to 11, wherein the ion species to be measured in the all-solid-state ion-selective electrode is at least one selected from the group consisting of alkali metal ions, alkaline earth metal ions, heavy metal ions, ammonium ions, nitrate ions, perchlorate ions, and chloride ions.

[0019] Item 13. An ion sensor comprising the all-solid-state ion-selective electrode according to any one of items 9 to 12.

[0020] Item 14. The ion sensor according to item 13, further comprising an external reference electrode.

[0021] Item 15. A method for manufacturing the insertion member for an all-solid-state ion-selective electrode according to any one of items 5 to 8, A step of drying the composition for an all-solid-state ion-selective electrode according to any one of items 1 to 4 The manufacturing method comprising this.

Advantages of the Invention

[0022] According to the present invention, it is possible to provide an all-solid-state ion-selective electrode having structural strength and excellent measurement accuracy and potential stability.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Mode for Carrying Out the Invention

[0024] In this specification, when a numerical range is expressed as "A to B", it means A or more and B or less.

[0025] Also, "contain" includes any of "comprise", "consist essentially of", and "consist of".

[0026] 1. Composition for All-Solid-State Ion-Selective Electrode The composition for an all-solid-state ion-selective electrode of the present invention is a composition used for an insertion member for an all-solid-state ion-selective electrode and contains a water-absorbing resin.

[0027] By using a composition adopting such a configuration, an all-solid-state ion-selective electrode having structural strength, measurement accuracy comparable to that of a conventional liquid membrane type ion-selective electrode, and excellent potential stability can be provided. Further, according to the all-solid-state ion-selective electrode using the composition for an all-solid-state ion-selective electrode of the present invention, it becomes possible to accurately measure the ion concentration in a wide measurement range.

[0028] As the water-absorbing resin, there is no particular limitation as long as it can hold a liquid that dissolves ions, for example, water, and is a resin that is hardly soluble in water.

[0029] Specific examples of such water-absorbing resins include polyvinyl butyral resin, polyacrylate resin, polymethacrylate resin, polyurethane resin, and the like. Among them, from the viewpoints of the structural strength of the all-solid-state ion-selective electrode of the present invention, the measurement accuracy of ion concentration, potential stability, etc., polyvinyl butyral resin is preferable. These water-absorbing resins can be used as they are, or can be made into solutions in one or more solvents such as water and alcohol (ethanol, n-propyl alcohol, isopropyl alcohol, etc.). These water-absorbing resins can be used alone or in combination of two or more. In addition, known or commercially available products of these water-absorbing resins can be used.

[0030] Note that a water-soluble polymer (such as polyvinyl alcohol) dissolves when inserted into an aqueous solution and it is difficult to maintain a solid state. In addition, polyvinyl chloride resin used in a conventional insertion member for an all-solid-state ion-selective electrode can hardly hold water, and as a result, it is difficult to accurately measure ion concentration in a wide concentration range. When polyvinyl chloride resin is used here, when drying to form an insertion member, since the polyvinyl chloride resin has poor water retention ability, its conductivity tends to decrease.

[0031] In the composition for an all-solid-state ion-selective electrode of the present invention, the content of the above water-absorbing resin is not particularly limited, but from the viewpoints of the structural strength of the all-solid-state ion-selective electrode of the present invention, the measurement accuracy of ion concentration, potential stability, etc., when the total amount of the composition for an all-solid-state ion-selective electrode is 100% by mass, 3 to 20% by mass is preferable, and 5 to 10% by mass is more preferable.

[0032] The composition for an all-solid-state ion-selective electrode of the present invention can further contain an electrolyte.

[0033] When the composition for an all-solid-state ion-selective electrode of the present invention contains an electrolyte, the electrolyte contained is not particularly limited. However, considering the measurement of the target ion concentration by measuring the equilibrium potential, an electrolyte containing the ion species to be measured in the all-solid-state ion-selective electrode of the present invention is preferred. For example, when the all-solid-state ion-selective electrode of the present invention is a nitrate ion-selective electrode for measuring the nitrate ion concentration, the electrolyte in the composition for the all-solid-state ion-selective electrode of the present invention is preferably an electrolyte containing nitrate ions (particularly silver nitrate). When the all-solid-state ion-selective electrode of the present invention is a potassium ion-selective electrode for measuring the potassium ion concentration, the electrolyte in the composition for the all-solid-state ion-selective electrode of the present invention is preferably an electrolyte containing potassium ions (particularly potassium chloride).

[0034] From the above, the electrolyte preferably contains alkali metal ions (such as potassium ions and sodium ions), alkaline earth metal ions (such as magnesium ions and calcium ions), heavy metal ions (such as lead (II) ions, copper (II) ions, mercury (II) ions, silver (I) ions, cobalt (II) ions, etc.), ammonium ions, nitrate ions, perchlorate ions, chloride ions, etc.

[0035] Specific examples of the above electrolytes include silver nitrate, potassium nitrate, potassium chloride, sodium chloride, magnesium chloride, ammonium chloride, calcium nitrate, silver perchlorate, etc. These electrolytes can be used alone or in combination of two or more. Also, known or commercially available products can be used as these electrolytes.

[0036] In the composition for an all-solid-state ion-selective electrode of the present invention, the content of the above electrolyte is not particularly limited. However, from the viewpoints of the structural strength of the all-solid-state ion-selective electrode of the present invention, the measurement accuracy of the ion concentration, the potential stability, etc., when the total amount of the composition for the all-solid-state ion-selective electrode is 100% by mass, 0.02 to 0.50% by mass is preferred, and 0.05 to 0.20% by mass is more preferred.

[0037] The composition for an all-solid-state ion-selective electrode of the present invention can use one or more solvents such as water, alcohol (ethanol, n-propyl alcohol, isopropyl alcohol, etc.) so that the above-mentioned water-absorbing resin can be impregnated or retained with the solvent. In this case, in the composition for an all-solid-state ion-selective electrode of the present invention, the content of the above-mentioned solvent is not particularly limited. However, from the viewpoints of the structural strength of the all-solid-state ion-selective electrode of the present invention, the measurement accuracy of the ion concentration, the potential stability, etc., when the total amount of the composition for an all-solid-state ion-selective electrode is 100% by mass, 80.0 to 99.9% by mass is preferable, and 85.0 to 99.8% by mass is more preferable.

[0038] By adopting the above-mentioned composition for an all-solid-state ion-selective electrode, it is possible to provide an all-solid-state ion-selective electrode having structural strength, measurement accuracy comparable to that of a conventional liquid membrane type ion-selective electrode, and excellent potential stability. Therefore, it is particularly useful for use in an all-solid-state ion-selective electrode.

[0039] 2. Insertion Member for All-Solid-State Ion-Selective Electrode The insertion member for an all-solid-state ion-selective electrode of the present invention is an insertion member for an all-solid-state ion-selective electrode for use in an all-solid-state ion-selective electrode, and contains a water-absorbing resin.

[0040] As the above-mentioned water-absorbing resin, those described in the above "1. Composition for an all-solid-state ion-selective electrode" can be adopted. Preferred specific examples are the same.

[0041] By adopting a water-absorbing resin for the insertion member for an all-solid-state ion-selective electrode in this way, it is possible to provide an all-solid-state ion-selective electrode having structural strength, measurement accuracy comparable to that of a conventional liquid membrane type ion-selective electrode, and excellent potential stability.

[0042] In the insertion member for the all-solid-state ion-selective electrode of the present invention, the content of the above water-absorbing resin is not particularly limited. However, from the viewpoints of the structural strength of the all-solid-state ion-selective electrode of the present invention, the measurement accuracy of ion concentration, potential stability, etc., when the total amount of the insertion member for the all-solid-state ion-selective electrode is 100% by mass, 95.0 to 99.8% by mass is preferable, and 98.0 to 99.5% by mass is more preferable.

[0043] The insertion member for the all-solid-state ion-selective electrode of the present invention can further contain an electrolyte.

[0044] As the electrolyte, those described in the above "1. Composition for all-solid-state ion-selective electrode" can be adopted. Preferred specific examples are the same.

[0045] In the insertion member for the all-solid-state ion-selective electrode of the present invention, the content of the above electrolyte is not particularly limited. However, from the viewpoints of the structural strength of the all-solid-state ion-selective electrode of the present invention, the measurement accuracy of ion concentration, potential stability, etc., when the total amount of the insertion member for the all-solid-state ion-selective electrode is 100% by mass, 0.2 to 5.0% by mass is preferable, and 0.5 to 2.0% by mass is more preferable.

[0046] The insertion member for the all-solid-state ion-selective electrode of the present invention is not particularly limited. However, from the viewpoints of the structural strength of the all-solid-state ion-selective electrode of the present invention, the measurement accuracy of ion concentration, potential stability, etc., it can be in the form of a film (insertion film for all-solid-state ion-selective electrode). When the insertion member for the all-solid-state ion-selective electrode of the present invention is in the form of a film, the thickness is not particularly limited. However, from the viewpoints of the measurement accuracy of ion concentration, stability, etc., of the all-solid-state ion-selective electrode of the present invention, 50 to 200 μm is preferable, and 70 to 100 μm is more preferable.

[0047] By adopting the above-described insertion member for an all-solid-state ion-selective electrode, it is possible to accurately measure the ion concentration within a wide concentration range and to provide an all-solid-state ion-selective electrode having excellent stability. Therefore, it is particularly useful for use as an insertion member in an all-solid-state ion-selective electrode. The configurations other than the insertion member in the all-solid-state ion-selective electrode will be described later.

[0048] 3. Manufacturing Method of Insertion Member for All-Solid-State Ion-Selective Electrode The manufacturing method of the insertion member for an all-solid-state ion-selective electrode of the present invention is not particularly limited, but it can be manufactured by a step of drying the composition for an all-solid-state ion-selective electrode (solution containing a water-absorbing resin) of the present invention.

[0049] When the composition for an all-solid-state ion-selective electrode of the present invention contains the above-described electrolyte, for example, it has a configuration in which the electrolyte is dissolved in a solvent impregnated with a water-absorbing resin. By drying the composition for an all-solid-state ion-selective electrode of the present invention, the insertion member for an all-solid-state ion-selective electrode of the present invention in which a high-concentration solution is held in the gaps of the water-absorbing resin can be obtained.

[0050] The drying method is not particularly limited as long as it can form the insertion member for an all-solid-state ion-selective electrode of the present invention. For example, as will be described later, when forming in a film shape on the internal reference electrode, a solution containing a water-absorbing resin can be applied and dried on the internal reference electrode.

[0051] At this time, the coating method and the drying method are not particularly limited and can be carried out according to conventional methods.

[0052] Also, the coating amount of the composition for an all-solid-state ion-selective electrode of the present invention is not particularly limited and can be adjusted to have the above-described thickness.

[0053] 4. All-Solid-State Ion-Selective Electrode The all-solid-state ion-selective electrode of the present invention includes an insertion member for the all-solid-state ion-selective electrode of the present invention, and for other configurations, it can be the same as the conventionally known all-solid-state ion-selective electrode. For example, the all-solid-state ion-selective electrode of the present invention can further include an internal reference electrode and an ion-selective sensing member. Specifically, the all-solid-state ion-selective electrode of the present invention can include an internal reference electrode, an insertion member, and an ion-selective sensing member in this order and can be electrically connected.

[0054] (4-1) Internal reference electrode As the internal reference electrode, those that can be used as the internal reference electrode in the conventionally known all-solid-state ion-selective electrode can be used. Specifically, examples of the internal reference electrode include a silver electrode, a silver / silver chloride electrode, etc. Among them, from the viewpoints of the structural strength of the all-solid-state ion-selective electrode of the present invention, the measurement accuracy of the ion concentration, the potential stability, etc., the use of a silver electrode is preferable. These internal reference electrodes can use known or commercially available products.

[0055] (4-2) Insertion member The insertion member can be the insertion member for the all-solid-state ion-selective electrode of the present invention described above.

[0056] (4-3) Ion-selective sensing member As the ion-selective sensing member, those that can be used as the ion-selective sensing member in the conventionally known all-solid-state ion-selective electrode can be used, and it preferably contains an electrolyte containing the ion species to be measured, a plasticizer, and a polymer for the ion-selective sensing member. Further, when the ion to be measured in the all-solid-state ion-selective electrode of the present invention is a cation, it can further contain an ionophore.

[0057] The electrolyte is not particularly limited, but is preferably a salt of an ion to be measured and a hydrophobic ion serving as its counter ion. The ion to be measured is, as described above, an alkali metal ion (such as potassium ion, sodium ion, etc.), an alkaline earth metal ion (such as magnesium ion, calcium ion, etc.), a heavy metal ion (such as lead (II) ion, copper (II) ion, mercury (II) ion, silver (I) ion, cobalt (II) ion, etc.), ammonium ion, nitrate ion, perchlorate ion, chloride ion, etc. Examples of the hydrophobic ion include tetrahexylammonium ion, tetraheptylammonium ion, tetrakis[3,5-bis(trifluoromethyl)phenylborate] ion, tetraphenylborate ion, etc. For example, tetrabutylammonium nitrate, tetrahexylammonium nitrate, tetraheptylammonium nitrate, tetrabutylammonium nitrate, tetrahexylammonium tetraphenylborate, tetraheptylammonium tetraphenylborate, tetrabutylammonium tetraphenylborate, tetrahexylammonium perchlorate, tetraheptylammonium perchlorate, tetrabutylammonium perchlorate, etc. These electrolytes can be used alone or in combination of two or more. Also, these electrolytes can be known or commercially available products.

[0058] In the ion-selective sensitive member, the content of the above electrolyte is not particularly limited, but from the viewpoints of the structural strength of the all-solid-state ion-selective electrode of the present invention, the measurement accuracy of the ion concentration, the potential stability, etc., with the total amount of the ion-selective sensitive member being 100% by mass, 0.05 to 10.0% by mass is preferable, and 0.1 to 5.0% by mass is more preferable.

[0059] Examples of the plasticizer include bis(1-butylpentyl) decane-1,10-diyl diglutalate (ETH469), 2-nitrophenyl octyl ether (NPOE), 2-nitrophenyl dodecyl ether, 2-nitrophenyl phenyl ether, 4-nitrophenyl phenyl ether, 2-fluoro-2'-nitrodiphenyl ether, dibutyl sebacate, dioctyl sebacate, bis(2-ethylhexyl) sebacate, bis(1-butylpentyl) adipate, dibutyl phthalate, dioctyl phthalate, dioctyl phenyl phosphate, dibenzyl ether, decanol, and the like. These plasticizers can be used alone or in combination of two or more. Further, known or commercially available products can be used as these plasticizers.

[0060] In the ion-selective sensitive member, the content of the above plasticizer is not particularly limited. However, from the viewpoints of the structural strength of the all-solid-state ion-selective electrode of the present invention, the measurement accuracy of the ion concentration, the potential stability, etc., when the total amount of the ion-selective sensitive member is 100% by mass, 0.05 to 10.0% by mass is preferable, and 0.1 to 5.0% by mass is more preferable. In addition, when the plasticizer is a liquid, the content of the plasticizer can also be an excessive amount.

[0061] Specific examples of the polymer for the ion-selective sensitive member include polyvinyl chloride resin, polystyrene resin, polyacrylate resin, polymethacrylate resin, polyurethane resin, polysiloxane resin, and the like. These polymers for the ion-selective sensitive member can be used as they are. These polymers for the ion-selective sensitive member can be used alone or in combination of two or more. Further, known or commercially available products can be used as these polymers for the ion-selective sensitive member.

[0062] In the ion-selective sensitive member, the content of the polymer for the ion-selective sensitive member described above is not particularly limited. However, from the viewpoints of the structural strength of the all-solid-state ion-selective electrode of the present invention, the measurement accuracy of the ion concentration, the potential stability, etc., when the total amount of the ion-selective sensitive member is 100% by mass, 80.0 to 99.9% by mass is preferable, and 90.0 to 99.8% by mass is more preferable. When the polymer for the ion-selective sensitive member is a solution, the content of the polymer for the ion-selective sensitive member can also be an excessive amount.

[0063] In the ion-selective sensitive member, when containing an ionophore, examples of the ionophore include valinomycin, monensin, rhodopsin, nonactin, monactin, ionomycin, gramicidin A, nigericin, CCCP (carbonyl cyanide-m-chlorophenylhydrazone), FCCP (carbonyl cyanide-p-trifluoromethoxyphenylhydrazone), crown ether (bis(12-crown-4)(bis[(12-crown-4)methyl]2-dodecyl-2-methylmalonate), etc.), acyclic nonylphenoxypolyethanol, bis(4-n-octylphenyl)phosphate, and the like. These ionophores can be used alone or in combination of two or more. Also, these ionophores can be known or commercially available products.

[0064] In the ion-selective sensitive member, the content of the ionophore described above is not particularly limited. However, from the viewpoints of the structural strength of the all-solid-state ion-selective electrode of the present invention, the measurement accuracy of the ion concentration, the potential stability, etc., when the total amount of the ion-selective sensitive member is 100% by mass, 0.5 to 5% by mass is preferable, and 1 to 3% by mass is more preferable.

[0065] The ion-selective sensitive member is not particularly limited, but from the viewpoints of the measurement accuracy, stability, etc. of the ion concentration of the all-solid-state ion-selective electrode of the present invention, it can be made into a film shape (ion-selective sensitive film). When the ion-selective sensitive member is in the form of a film, the thickness of the ion-selective sensitive member is not particularly limited, but from the viewpoints of the structural strength of the all-solid-state ion-selective electrode of the present invention, the measurement accuracy of the ion concentration, the potential stability, etc., 50 to 200 μm is preferable, and 70 to 100 μm is more preferable.

[0066] The manufacturing method of the ion-selective sensitive member is not particularly limited. For example, it can be manufactured by a process of drying a solution containing an electrolyte, a plasticizer, a polymer for the ion-selective sensitive member, and an ionophore as required.

[0067] In the solution containing an electrolyte, a plasticizer, a polymer for the ion-selective sensitive member, and an ionophore as required, the solvent constituting the solution is not particularly limited, but a solvent capable of dissolving the electrolyte, the plasticizer, the polymer for the ion-selective sensitive member, and the ionophore as required, which contains the ion species to be measured, is preferable. For example, it can be one or more solvents such as tetrahydrofuran, N-methyl-2-pyrrolidone, and methyl ethyl ketone.

[0068] In the solution containing an electrolyte, a plasticizer, a polymer for the ion-selective sensitive member, and an ionophore as required, the concentration of the electrolyte, the plasticizer, the polymer for the ion-selective sensitive member, and the ionophore as required, which contains the ion species to be measured, is not particularly limited because the solvent is removed by drying when manufacturing the ion-selective sensitive member. It can be set to a concentration that can dissolve the electrolyte, the plasticizer, the polymer for the ion-selective sensitive member, and the ionophore as required, which contains the ion species to be measured.

[0069] The drying method is not particularly limited as long as it can form an ion-selective sensitive member. For example, when forming an ion-selective sensitive member in a film shape on the above-described insertion member, a solution containing an electrolyte, a plasticizer, a polymer for an ion-selective sensitive member, and an ionophore as needed, which contains the ion species to be measured, is applied on the above-described insertion member and dried.

[0070] At this time, the coating method and the drying method are not particularly limited and can be carried out according to conventional methods.

[0071] In addition, the coating amount of the solution containing an electrolyte, a plasticizer, a polymer for an ion-selective sensitive member, and an ionophore as needed, which contains the ion species to be measured, is not particularly limited and can be adjusted to have the above-described thickness.

[0072] (4-4) All-solid-state ion-selective electrode For the all-solid-state ion-selective electrode of the present invention, as for the configuration other than the above, the configuration of a conventional all-solid-state ion-selective electrode can be adopted.

[0073] In addition, the all-solid-state ion-selective electrode of the present invention as described above does not use an internal solution, is easy to miniaturize, is easy to devise the shape such as printing production of the electrode, and is physically strong, so that direct measurement in soil is possible. Further, the all-solid-state ion-selective electrode of the present invention can accurately measure the ion concentration in a wide concentration range and is also excellent in stability.

[0074] The ion species that can be measured by the all-solid-state ion-selective electrode of the present invention are not particularly limited, and may be alkali metal ions (such as potassium ions, sodium ions, etc.), alkaline earth metal ions (such as magnesium ions, calcium ions, etc.), heavy metal ions (such as lead (II) ions, copper (II) ions, mercury (II) ions, silver (I) ions, cobalt (II) ions, etc.), ammonium ions, nitrate ions, perchlorate ions, chloride ions, etc. That is, the all-solid-state ion-selective electrode of the present invention can be an alkali metal ion-selective electrode (such as a potassium ion-selective electrode, a sodium ion-selective electrode, etc.), an alkaline earth metal ion-selective electrode (such as a magnesium ion-selective electrode, a calcium ion-selective electrode, etc.), a heavy metal ion-selective electrode (such as a lead (II) ion-selective electrode, a copper (II) ion-selective electrode, a mercury (II) ion-selective electrode, a silver (I) ion-selective electrode, a cobalt (II) ion-selective electrode, etc.), an ammonium ion-selective electrode, a nitrate ion-selective electrode, a perchlorate ion-selective electrode, a chloride ion-selective electrode, etc.

[0075] The all-solid-state ion-selective electrode of the present invention as described above can be immersed in a sample solution together with, for example, an external reference electrode or a salt bridge of an external reference electrode, and the potential difference between these two electrodes can be measured, for example, by a potentiometer. When the all-solid-state ion-selective electrode of the present invention is used, since the target ion concentration in the sample solution shows a Nernst response in a wide range (there is a proportional relationship in which the logarithm of the ion concentration and the potential difference change linearly), it is possible to measure the target ion concentration from the result of the measured potential difference. In addition, since the all-solid-state ion-selective electrode of the present invention is also excellent in stability, it is also possible to continuously measure the target ion concentration over a long period of time.

[0076] Specific embodiments to which the all-solid-state ion-selective electrode of the present invention as described above is applied include test pieces for measuring ion concentration. Examples of the measurement sample for measuring ion concentration include biological samples such as blood, urine, saliva, cerebrospinal fluid, sweat, etc., as well as environmental water, soil, etc., and can be used in clinical analyzers, water quality analyzers, soil analyzers, food analyzers, etc.

Example

[0077] Hereinafter, examples and comparative examples will be given to specifically describe the present invention, but the present invention is not limited only to the examples.

[0078] In the following examples, all reagents were used without purification of commercially available reagent-grade products.

[0079] Example 1: All-Solid-State Nitrate Ion-Selective Electrode First, 3.3 mg of silver nitrate was added to 10 g of an aqueous isopropyl alcohol solution of polybutyral resin (PVB resin) (Esrec K manufactured by Sekisui Chemical Co., Ltd.) and stirred well, resulting in turbidity. The obtained turbid solution was applied at 0.35 g to a 3 cm × 3 cm range on a silver plate (3 cm × 5 cm, thickness 1 mm) and dried overnight, and an electrolyte-containing polymer film (PM; thickness 70 to 100 μm) was formed on the silver plate which is the internal reference electrode.

[0080] Next, 15 mg of tetraheptylammonium nitrate (THpANO3), 6 mL of 2-nitrophenyl octyl ether (NPOE), 30 mL of a polyvinyl chloride resin (PVC resin; isopropyl alcohol solution) containing 3 g of PVC resin, and 30 mL of tetrahydrofuran were mixed and stirred well. The obtained solution was applied at 0.15 g on the electrolyte-containing polymer film (PM) prepared as described above and dried overnight, and an ion-selective sensitive film (ISM; thickness 70 to 100 μm) was formed on the electrolyte-containing polymer film (PM).

[0081] The obtained electrode was used as the all-solid-state ion-selective electrode (all-solid-state nitrate ion-selective electrode) of Example 1.

[0082] The composition of the aqueous isopropyl alcohol solution of polybutyral resin (PVB resin) (Esrec K manufactured by Sekisui Chemical Co., Ltd.) used is shown below.

[0083] [Table 1]

[0084] Example 2: All-Solid-State Nitrate Ion-Selective Electrode The total solid ion selective electrode (total solid nitrate ion selective electrode) of Example 2 was obtained in the same manner as in Example 1, except that the amount of silver nitrate added was 18.0 mg.

[0085] Example 3: All-Solid-State Nitrate Ion-Selective Electrode The total solid ion selective electrode (total solid nitrate ion selective electrode) of Example 3 was obtained in the same manner as in Example 1, except that the amount of silver nitrate added was 110.0 mg.

[0086] Test Example 1: Measurement of Nitrate Ion Concentration The total solid ion selective electrodes (total solid nitrate ion selective electrodes) obtained in Examples 1 to 3 were sandwiched between two bottom plates of the cell, and a glass tube containing a sample solution (aqueous sodium nitrate solution) was fixed so that the sample solution came into contact with the total solid ion selective electrode (total solid nitrate ion selective electrode). Next, a salt bridge connected to a silver / silver chloride electrode as an external reference electrode was inserted into the sample solution to fabricate a nitrate ion concentration measuring device. The appearance of the obtained nitrate ion concentration measuring device is shown in FIG. 1.

[0087] In the sample solution, the nitrate ion concentration was changed from 10 -6 mol / L to 10 -1 mol / L (10 -6 mol / L, 10 -5 mol / L, 10 -4 mol / L, 10 -3 mol / L, 10 -2 mol / L or 10 -1 mol / L), and the potential difference E ISE between the total solid ion selective electrodes (total solid nitrate ion selective electrodes) obtained in Examples 1 to 3 and the external reference electrode at each concentration was measured. The results are shown in FIGS. 2 to 4. The slope of the graph is also shown in the figures.

[0088] As can be understood from FIGS. 2 to 4, in the range where the nitrate ion concentration in the sample solution is 10 -5 to 10 -1 mol / L, the measured potential difference changes linearly, and the nitrate ion concentration a NO3-was proportional to the logarithm. The potential difference E of the all-solid-state ion-selective electrode to be measured ISE As shown in FIG. 5, it can be understood that, in calculation, using the Nernst equation, it is proportional to the logarithm of the nitrate ion concentration a NO3- to be measured. Therefore, it is shown that it is in agreement with the theory when the nitrate ion concentration in the sample solution is in the range of 10 -5 to 10 -1 mol / L.

[0089] Test Example 2: Evaluation of Stability (Part 1) The all-solid-state ion-selective electrode (all-solid-state nitrate ion-selective electrode) obtained in Example 2 was immersed in an aqueous sodium nitrate solution of 10 -3 mol / L, and a salt bridge connected to a silver / silver chloride electrode as an external reference electrode was immersed. Periodically, for 12 hours from the immersion, the potential difference E ISE between the all-solid-state ion-selective electrode (all-solid-state nitrate ion-selective electrode) and the external reference electrode was measured in the same manner as in Test Example 1. The results are shown in FIG. 6. From this result, it can be understood that there is no shift in the potential difference and it has high stability.

[0090] Test Example 3: Evaluation of Stability (Part 2) The all-solid-state ion-selective electrode (all-solid-state nitrate ion-selective electrode) obtained in Example 2 was stored in ultrapure water for one week or three weeks. Then, the all-solid-state ion-selective electrode (all-solid-state nitrate ion-selective electrode) before storage or after three weeks of storage was immersed in an aqueous sodium nitrate solution of 10 -3 mol / L, and a salt bridge connected to a silver / silver chloride electrode as an external reference electrode was immersed. The potential difference E ISE between the all-solid-state ion-selective electrode (all-solid-state nitrate ion-selective electrode) and the external reference electrode was measured in the same manner as in Test Example 1. The results are shown in FIG. 7.

[0091] Also, the all-solid-state ion-selective electrode (all-solid-state nitrate ion-selective electrode) before storage, after one week of storage, or after three weeks of storage was immersed in an aqueous sodium nitrate solution, and a salt bridge connected to a silver / silver chloride electrode as an external reference electrode was immersed. In the sample solution, in the same manner as in Test Example 1, the nitrate ion concentration was changed from 10 -6 mol / L to 10 -1up to mol / L (10 -6 mol / L, 10 -5 mol / L, 10 -4 mol / L, 10 -3 mol / L, 10 -2 mol / L or 10 -1 mol / L), the potential difference E ISE between the all-solid-state ion-selective electrode (all-solid-state nitrate ion-selective electrode) and the external reference electrode at each concentration was measured. The results are shown in Fig. 8.

[0092] As a result, the sensitivity was maintained even after 3 weeks, indicating high stability. That is, it can be understood that silver nitrate was retained in the electrolyte-containing polymer film (PM) even after storage for 3 weeks, and the target ion concentration could be measured accurately.

[0093] Example 4: All-Solid-State Potassium Ion-Selective Electrode First, 3.0 mg of potassium chloride was added to 10 g of an aqueous isopropyl alcohol solution of polybutyral resin (Esrec K manufactured by Sekisui Chemical Co., Ltd.) and stirred well, resulting in turbidity. The obtained turbid solution was applied in an amount of 0.35 g to a 3 cm × 3 cm area on a silver plate (3 cm × 5 cm, thickness 1 mm) coated with silver chloride on the surface and dried overnight. An electrolyte-containing polymer film (PM; thickness 70 - 100 μm) was prepared on the silver plate, which serves as the internal reference electrode.

[0094] Next, 15 mg of potassium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (KTFPB), 6 mL of 2-nitrophenyloctyl ether (NPOE), 3 g of polyvinyl chloride resin (PVC resin), 30 mL of tetrahydrofuran, and 11 mg of valinomycin (ionophore corresponding to potassium ions) were mixed and stirred well. The obtained solution was applied in an amount of 0.15 g on the electrolyte-containing polymer film (PM) prepared as described above and dried overnight. An ion-selective sensitive membrane (ISM; thickness 70 - 100 μm) was prepared on the electrolyte-containing polymer film (PM).

[0095] The obtained electrode was used as the all-solid-state ion-selective electrode (all-solid-state potassium ion-selective electrode) of Example 4.

[0096] The composition of the isopropyl alcohol aqueous solution of polybutyral resin (PVB resin) (Esrec K manufactured by Sekisui Chemical Co., Ltd.) used was the same as that in Example 1 above.

[0097] Example 5: All-Solid-State Ammonium Ion-Selective Electrode First, 3.0 mg of ammonium chloride was added to 10 g of an isopropyl alcohol aqueous solution of polybutyral resin (PVB resin) (Esrec K manufactured by Sekisui Chemical Co., Ltd.) and stirred well, resulting in turbidity. The obtained turbid solution was applied in an amount of 0.35 g to a 3 cm × 3 cm area on a silver plate (3 cm × 5 cm, thickness 1 mm) coated with silver chloride on the surface and dried overnight. An electrolyte-containing polymer film (PM; thickness 70 to 100 μm) was formed on the silver plate serving as the internal reference electrode.

[0098] Next, 15 mg of ammonium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (NH4TFPB), 6 mL of 2-nitrophenyloctyl ether (NPOE), 3 g of polyvinyl chloride resin (PVC resin), 30 mL of tetrahydrofuran, and 42 mg of nonactin (ionophore corresponding to ammonium ions) were mixed and stirred well. The obtained solution was applied in an amount of 0.15 g onto the electrolyte-containing polymer film (PM) prepared as described above and dried overnight. An ion-selective sensitive film (ISM; thickness 70 to 100 μm) was formed on the electrolyte-containing polymer film (PM).

[0099] The obtained electrode was used as the all-solid-state ion-selective electrode (all-solid-state ammonium ion-selective electrode) of Example 5.

[0100] The composition of the isopropyl alcohol aqueous solution of polybutyral resin (PVB resin) (Esrec K manufactured by Sekisui Chemical Co., Ltd.) used was the same as that in Example 1 above.

[0101] Example 6: All-Solid-State Sodium Ion-Selective Electrode First, 3.0 mg of sodium chloride was added to 10 g of an isopropyl alcohol aqueous solution of polyvinyl butyral resin (PVB resin) (Esrec K manufactured by Sekisui Chemical Co., Ltd.), and when it was stirred well, it became turbid. The obtained turbid solution was applied at 0.35 g to a range of 3 cm × 3 cm on a silver plate (3 cm × 5 cm, thickness 1 mm) coated with silver chloride on its surface, dried overnight, and an electrolyte-containing polymer film (PM; thickness 70 to 100 μm) was formed on the silver plate which is an internal reference electrode.

[0102] Next, 15 mg of sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (NaTFPB), 6 mL of 2-nitrophenyloctyl ether (NPOE), 3 g of polyvinyl chloride resin (PVC resin), 30 mL of tetrahydrofuran, and 96 mg of bis(12-crown-4) (ionophore corresponding to sodium ion; bis[(12-crown-4)methyl] 2-dodecyl-2-methylmalonate) were mixed and stirred well. The obtained solution was applied at 0.15 g on the electrolyte-containing polymer film (PM) prepared as described above, dried overnight, and an ion-selective sensitive film (ISM; thickness 70 to 100 μm) was formed on the electrolyte-containing polymer film (PM).

[0103] The obtained electrode was used as the all-solid ion-selective electrode (all-solid sodium ion-selective electrode) of Example 6.

[0104] Note that the composition of the isopropyl alcohol aqueous solution of the polyvinyl butyral resin (PVB resin) used (Esrec K manufactured by Sekisui Chemical Co., Ltd.) is the same as that of Example 1 above.

[0105] Example 7: All-Solid-State Calcium Ion-Selective Electrode First, 8.0 mg of sodium chloride was added to 10 g of an isopropyl alcohol aqueous solution of polyvinyl butyral resin (PVB resin) (Esrec K manufactured by Sekisui Chemical Co., Ltd.), and when it was stirred well, it became turbid. The obtained turbid solution was applied in an amount of 0.35 g to a range of 3 cm × 3 cm on a silver plate (3 cm × 5 cm, thickness 1 mm) coated with silver chloride on the surface, and dried overnight. An electrolyte-containing polymer film (PM; thickness 70 to 100 μm) was formed on the silver plate which is an internal reference electrode.

[0106] Next, 15 mg of calcium bis[tetrakis{3,5-bis(trifluoromethyl)phenyl}borate] (Ca(TFPB)2), 6 mL of 2-nitrophenyloctyl ether (NPOE), 3 g of polyvinyl chloride resin (PVC resin), 30 mL of tetrahydrofuran, and 35 mg of calcium bis(4-n-octylphenyl)phosphate salt (ionophore corresponding to calcium ions) were mixed and stirred well. The obtained solution was applied in an amount of 0.15 g on the electrolyte-containing polymer film (PM) prepared as described above, and dried overnight. An ion-selective sensitive film (ISM; thickness 70 to 100 μm) was formed on the electrolyte-containing polymer film (PM).

[0107] The obtained electrode was used as the all-solid-state ion-selective electrode (all-solid-state calcium ion-selective electrode) of Example 7.

[0108] The composition of the isopropyl alcohol aqueous solution of polyvinyl butyral resin (PVB resin) used was the same as that of Example 1 above.

[0109] Test Example 4: Measurement of Concentrations of Various Ions A glass tube containing a sample solution (an aqueous solution containing the ions to be measured) was fixed so that the all-solid-state ion-selective electrode obtained in Examples 4 to 7 (all-solid-state potassium ion-selective electrode, all-solid-state ammonium ion-selective electrode, all-solid-state sodium ion-selective electrode, or all-solid-state calcium ion-selective electrode) was in contact with the sample solution. Next, a salt bridge connected to a silver / silver chloride electrode, which is an external reference electrode, was placed in the sample solution, and an ion concentration measuring device (potassium ion concentration measuring device, ammonium ion concentration measuring device, sodium ion concentration measuring device, or calcium ion concentration measuring device) was manufactured.

[0110] In the sample solution, the concentration of the ion to be measured was changed from 10 -6 mol / L to 10 -1 mol / L (10 -6 mol / L, 10 -5 mol / L, 10 -4 mol / L, 10 -3 mol / L, 10 -2 mol / L, or 10 -1 mol / L), and the potential difference E ISE between the all-solid-state ion-selective electrode obtained in Examples 4 to 7 (all-solid-state potassium ion-selective electrode, all-solid-state ammonium ion-selective electrode, all-solid-state sodium ion-selective electrode, or all-solid-state calcium ion-selective electrode) and the external reference electrode at each concentration was measured. The results are shown in FIG. 9 and Table 2.

[0111]

Table 2

[0112] As can be understood from FIG. 9, in the range where the concentration of the ion to be measured in the sample solution was 10 -5 to 10 -1 mol / L, the measured potential difference changed linearly and was proportional to the logarithm of the concentration of the ion to be measured. Since it can be understood that the potential difference E ISE of the measured all-solid-state ion-selective electrode is, in theory, proportional to the logarithm of the ion concentration to be measured using the Nernst equation, when the concentration of the ion to be measured in the sample solution is 10-5 ~10 -1 In the range of ~10 mol / L, it has been shown to be consistent with the theory.

[0113] Table 2 shows the slope of the graph in Fig. 9 (response characteristic; Sensitivity). Also, Table 2 shows the region where the potential changes almost linearly in Fig. 9 (linear response region; Linear range). As a result, for any ion, since it is proportional to the logarithm of the ion concentration to be measured in a wide concentration range, it can be used as an ion sensor for various ions, and it can be understood that it has a response characteristic comparable to that of nitrate ions.

Claims

1. A composition for an all-solid-state ion-selective electrode used for an insertion member of an all-solid-state ion-selective electrode, containing a water-absorbing resin.

2. The composition for an all-solid-state ion-selective electrode according to claim 1, wherein the water-absorbing resin is a polyvinyl butyral resin.

3. The composition for an all-solid-state ion-selective electrode according to claim 1, further containing an electrolyte containing an ion species to be measured.

4. The composition for an all-solid-state ion-selective electrode according to claim 3, wherein the ion species is at least one selected from the group consisting of alkali metal ions, alkaline earth metal ions, heavy metal ions, ammonium ions, nitrate ions, perchlorate ions, and chloride ions.

5. An insertion member for an all-solid-state ion-selective electrode containing a water-absorbing resin.

6. The insertion member for an all-solid-state ion-selective electrode according to claim 5, wherein the water-absorbing resin is a polyvinyl butyral resin.

7. The insertion member for an all-solid-state ion-selective electrode according to claim 5, further containing an electrolyte containing an ion species to be measured.

8. The insertion member for an all-solid-state ion-selective electrode according to claim 7, wherein the ion species is at least one selected from the group consisting of alkali metal ions, alkaline earth metal ions, heavy metal ions, ammonium ions, nitrate ions, perchlorate ions, and chloride ions.

9. An all-solid-state ion-selective electrode comprising the insertion member for an all-solid-state ion-selective electrode according to any one of claims 4 to 8.

10. Further comprising an internal reference electrode and an ion-selective sensing member, The all-solid-state ion-selective electrode according to claim 9, wherein the internal reference electrode, the insertion member for the all-solid-state ion-selective electrode, and the ion-selective sensitive member are electrically connected in this order.

11. The all-solid-state ion-selective electrode according to claim 10, wherein the ion-selective sensitive member contains an electrolyte containing an ion species to be measured, a plasticizer, and a polymer for the ion-selective sensitive member.

12. The all-solid-state ion-selective electrode according to claim 9, wherein the ion species to be measured in the all-solid-state ion-selective electrode is at least one selected from the group consisting of an alkali metal ion, an alkaline earth metal ion, a heavy metal ion, an ammonium ion, a nitrate ion, a perchlorate ion, and a chloride ion.

13. An ion sensor comprising the all-solid-state ion-selective electrode according to claim 9.

14. The ion sensor according to claim 13, further comprising an external reference electrode.

15. A method for manufacturing an insertion member for an all-solid-state ion-selective electrode according to any one of claims 5 to 8, The step of drying the composition for an all-solid-state ion-selective electrode according to any one of claims 1 to 4 The manufacturing method comprising this.

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