JPH09178690A - Ion sensor and method for measuring ion concentration - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ion sensor suitable for disposal which is formed by making an ion sensing polar and a reference polar to be integral and can measure the ion concentration through easy and simple operation. SOLUTION: An ion sensor 1 is provided with, on single supporting substrate, a solid-state ion sensing polar 3 using a solid electrolyte, a reference polar 4 including a water absorbing member, an electrolytic solution accumulating part 8 which is filled with an electrolytic solution 6 by a damageable diaphragm 5, a movable seeping member 7 including a needle-like part made of porous material, and a dispersing member 9 which disperses a dropped liquid to be tested and allows it to be brought into contact with a seeping electrolytic solution through the seeping member. When the ion concentration is subjected to measurement, the member 7 is penetrated into the diaphragm 5 to allow the solution 6 to seep therefrom, and after a liquid to be tested is dropped, it is partly dispersed on the member 9 and brought into contact with the electrolytic solution.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an ion sensor used for measuring the concentration of a specific ion present in a solution in the chemical industry, food industry, medical treatment, environmental measurement, etc., and is particularly suitable for disposable applications. Regarding an ion sensor.

[0002]

2. Description of the Related Art An ion electrode method using an ion selective electrode (hereinafter, also referred to as an ion electrode) is known as a method for measuring a specific ion concentration in a solution. This method is usually performed by immersing a pair of an ion electrode and a reference electrode in a liquid to be measured and measuring the potential difference between the two electrodes using a measuring instrument such as an electrometer. As the ion electrode and the reference electrode usually used here, those having an internal liquid structure in which an electrolyte solution is enclosed are mainly used. This internal liquid structure has excellent measurement accuracy, but has the drawback that it requires maintenance and management and is not suitable for downsizing or integration. Also, some proposals have been made for those using a solid electrolyte as the ion-sensitive member, those gelling the internal liquid, or those having a completely solid electrode without using any internal liquid. It is inferior to the conventional internal liquid structure in terms of storage stability, measurement accuracy, and reproducibility over a period of time.

One of the applications of ion sensors is the analysis of electrolyte components in blood and urine in the medical field.
In this case, the disposable use of the sensor is desirable for hygiene, and high accuracy and storage stability are required. Further, it is required that the ion electrode and the reference electrode are integrated and miniaturized from the viewpoints that the measurement can be performed with a smaller amount of the test liquid and the measurement operation is simple.

In consideration of these points, a solid ion electrode and a reference electrode are arranged side by side on a single substrate, and a standard solution corresponding to the above internal solution is dropped on the reference electrode during measurement. A slide-type solid-state electrode that is adapted to measure is known. For example, in JP-A-58-212648 and JP-A-59-30055, a solid electrode pair composed of a solid electrode having an ion selective layer which selectively responds to a specific ion as an outermost layer is arranged. Disclosed is an ion activity measuring instrument provided with a porous bridge for achieving electrical conduction between both electrodes by permeation after supplying a test solution and a standard solution to electrode pairs, respectively.

[0005]

However, although the above-mentioned ion electrode has satisfactory performance with respect to measurement accuracy,
Since the standard solution must be spotted at the same time as the spotting of the test solution on the predetermined position of the solid electrode pair, the standard solution must be prepared each time the measurement is performed, and it is dedicated from the viewpoint of its operability. It has drawbacks such as consideration of using a pipette or the like. Therefore, the ion electrode is not always a simple measuring means even in the analytical use in the medical field.

The present invention has been made to solve the above drawbacks, and an object of the present invention is to provide an ion sensor in which an ion electrode and a reference electrode are integrated.
An object of the present invention is to provide an ion sensor that can perform highly accurate measurement easily, has excellent storage stability, and is suitable for disposable use.

[0007]

In order to solve the above problems, an ion sensor according to claim 1 of the present invention has a solid ion sensitive electrode using a solid electrolyte and a water absorbing member on the inner electrode. A solid reference electrode, an electrolyte solution reservoir in which an electrolyte solution is enclosed by a partition wall that is at least partially damaged or removable, and a partition wall that is damaged or removed to leach the electrolyte solution from the electrolyte solution reservoir area. The movable leaching member and the diffusing member for diffusing the dropped test liquid and bringing it into contact with the electrolyte solution leached by the leaching member.

Here, a part of the leaching member has a needle-shaped portion, and a part of the partition wall is made of a water resistant film into which the needle-shaped portion can be inserted. It is desirable to be composed of a hydrophilic porous body having Further, the leaching member may be provided with a fixing means for preventing the partition wall from being damaged or removed before use, and the diffusion member is made of a hydrophilic porous body having an open-air hole, The leaching member and the diffusion member are integrally formed, a plurality of ion sensitive electrodes using a solid electrolyte that selectively responds to different ion species are provided, and the solid electrolyte is made of ceramics, respectively. preferable.

Further, the ion concentration measuring method according to claim 9 of the present invention comprises a solid ion sensitive electrode using a solid electrolyte, a solid reference electrode having a water absorbing member on the inner electrode,
An electrolyte solution reservoir in which an electrolyte solution is enclosed by a partition, a movable leaching member for leaching the electrolyte solution from the electrolyte solution reservoir by damaging or removing the partition, and diffusing the dropped test liquid An ion concentration measuring method using an ion sensor comprising a diffusing member for contacting with an electrolyte solution leached by the leaching member,
After the partition wall is broken or removed by the operation of the leaching member to leaching the electrolyte solution, the water-absorbing member is caused to absorb part of the leached electrolyte solution, and the inner electrode is brought into contact with the electrolyte solution. A test liquid is dropped from above, and while contacting with the solid electrolyte by diffusing in the diffusion member, a part thereof is also contacted with the electrolyte solution leached by the leaching member, and the ion sensitive electrode and the reference electrode. It is characterized in that the potential difference generated between the two is measured.

Here, a part of the leaching member has a needle-shaped portion, and a part of the partition wall is made of a water resistant film into which the needle-shaped part can be inserted, and the needle-shaped part is pressed against the partition wall. Alternatively, it is damaged or removed by press-fitting, the electrolyte solution is leached from the electrolyte solution reservoir, and further, the needle-shaped portion is made of a hydrophilic porous body having continuous vents, and the electrolyte solution is Leaching through the continuous vents is particularly preferred. Further, the diffusion member is made of a hydrophilic porous body having continuous vents, the leaching member and the diffusion member are integrally formed, and the ion sensor selectively selects different ion species. It is preferable to provide a plurality of ion sensitive electrodes using a responsive solid electrolyte, to simultaneously measure the ion concentrations of a plurality of ion species, and to use a solid electrolyte made of ceramics.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The ion sensor of the present invention is one in which an ion sensitive electrode and a reference electrode are integrated, and the ion sensitive electrode and the reference electrode before use are solid electrodes and are used at the time of use. The electrolyte solution for ensuring the liquid conduction between the two electrodes can be leached from the separately provided reservoir to improve the storage stability before use and to maintain the measurement accuracy and simplify the operation. It is what That is, the ion sensor of the present invention, a solid ion sensitive electrode, a solid reference electrode having a water absorbing member,
An electrolyte solution reservoir formed by enclosing an electrolyte solution, a movable leaching member for leaching the electrolyte solution, and a diffusing member for bringing the dropped test liquid into contact with the electrolyte solution leached by the leaching member. It is basically composed of

When the above-mentioned ion sensor is manufactured, the ion sensitive electrode and the reference electrode are usually integrally formed on a support having an electrically insulating property. As the support at this time, glass, ceramics sintered body, acrylic resin, AB
Various materials such as S resin, polycarbonate resin, composite of epoxy resin and glass powder can be used, and particularly limited as long as they have excellent electrical insulation properties, processability, water resistance, handleability, etc. However, various shapes according to the usage of the ion sensor, such as a flat plate,
It can be used after being processed into a square rod shape, a cylindrical shape, a needle shape, or the like.

The ion sensitive electrode selectively responds to specific ions and is used as a solid electrode using a solid electrolyte. The solid-state electrode means an electrode of a type that does not require an internal liquid, which is built in a conventional electrode. The solid electrolyte is used as an ion-sensitive member (sensitive film) and may be the outermost layer of the ion-sensitive electrode, or may be covered with an ion-sensitive substance layer containing crown ether, valinomycin or the like. Usually, the ion sensitive electrode is composed of a combination of this solid electrolyte and an internal electrode for taking out its potential. As the internal electrode, a metal electrode is preferable, and for example, a copper clad laminate having an internal electrode portion and a terminal portion following the wiring formed by etching or a substrate having a thin metal conductor layer deposited thereon can be used. Can be used. The sensitive member may directly contact and fix a portion of the surface that does not come into contact with the test liquid to the internal electrode, but if it is fixed by adhesion via a solid or semi-solid conductive bridge material also called an ion bridge. This is preferable because a more stable potential can be taken out.

As the conductive bridge material, a material having both conductivity and adhesiveness is preferably used. For example, as a preferable example, a thermosetting carbon paste obtained by mixing carbon particles with a phenol resin is used,
It is preferable that one surface of the sensitive member made of a solid electrolyte coated with the paste is heated to a constant temperature while being in contact with one end of the conductor wiring (for example, copper) on the surface of the support to bond and cure the paste. Further, by using a salt obtained by adding salts such as sodium chloride and silver chloride to the carbon paste as a conductive bridge material, it is possible to improve the responsiveness and further stabilize the potential.

The solid electrolyte described above is, for example, Nasicon ceramics (Na _{1 + X} Zr ₂ Si _X P _3-X O).
₁₂ , 0 ≦ x ≦ 3), beta-alumina ceramics (M
₂ O.nAl ₂ O ₃ , 5 ≦ n ≦ 11, M is an alkali metal), lanthanum fluoride (LaF ₃ ), silver halide, silver sulfide, copper sulfide and the like can be preferably used. The ion species to be measured are almost determined by the material of the solid electrolyte, but in addition to sodium, ions of alkaline groups such as potassium and lithium, hydrogen ions, oxygen ions, fluorine ions, chlorine ions, carbonate ions, etc. Is mentioned. By providing a plurality of ion sensitive electrodes each having these different solid electrolytes as the outermost layers on a single support, it is possible to configure a multifunctional ion sensor capable of simultaneously measuring different ion species.

Of the above solid electrolytes, ion conductive ceramics such as NASICON and beta-alumina are particularly preferable as the sensitive member of the ion sensor of the present invention.
When these materials are used, it is desirable that the material is a dense sintered body, and the production thereof is performed according to the shape and size of the sensitive member by a known molding method (for example, die press molding method, slip cast molding method, etc.). ) And a firing method can be appropriately used. Since the ceramics sintered body has high mechanical strength and excellent machinability, it is easy to perform grinding and drilling after sintering, but the above processing is required at the stage of the molded body before sintering. It is also possible to sinter after application. In addition, the solid electrolyte membrane may be formed on the support in which the internal electrodes are formed in advance by using a technique such as a thick film method or a sputtering method.

The reference electrode is composed of an inner electrode and a water absorbing member. A concave portion having a certain depth is provided in the reference electrode forming portion of the support to form an internal pole at the bottom thereof, and the water absorbing member is arranged in contact with the upper portion or the internal pole. As the inner electrode, a so-called silver / silver chloride electrode in which a silver chloride layer is formed on the surface of metallic silver is usually particularly preferably used. As the water absorbent member, various water absorbent resins and the like can be used in addition to the hydrophilic porous body such as gauze and non-woven fabric.

It is particularly preferable that the electrolyte solution reservoir is integrally provided in the support body in which the ion sensitive electrode and the reference electrode are formed, and adjacent to the reference electrode. The electrolyte solution reservoir has a space capable of hermetically holding a fixed amount of electrolyte solution, and at least a part of the wall surface surrounding the space is constituted by a partition wall that can be damaged or removed. The partition must be capable of being damaged or removed in order to leach out the electrolyte solution therein during use of the ion sensor. Such a partition must be made of a water-resistant film material and attached to the support with a material and a shape that can be discarded or removed by the action of the leaching member. For example, the partition wall has a thickness of 20 to
It can be manufactured by using a 100 μm polyvinyl chloride film and adhering it to the open end of a polycarbonate frame by a thermal bonding method.

The electrolyte solution filled in the electrolyte solution reservoir is, for example, a saturated aqueous solution of potassium chloride, but may be a solution in which lithium chloride or the like is further dissolved as a stabilizer. Further, when the above-mentioned silver / silver chloride electrode is used as the inner electrode of the reference electrode, it is particularly preferable to dissolve silver chloride in the electrolyte solution in a saturated state because the stability of the reference potential is improved.

The leaching member is movably provided to damage or remove the partition wall, and has a function of leaching a part of the electrolyte solution in the electrolyte solution reservoir after the partition wall is damaged. For example, the leaching member is shaped such that a part such as a push pin has a needle-like portion, and the needle-like portion is arranged at a right angle to the front surface of the partition wall, and this is moved to the partition wall side to insert the needle into the partition wall. It is preferable to have a structure capable of moving a certain distance so that the moving can be performed. The leaching member is not limited to a specific shape as long as it can damage the partition wall, and for example, a plurality of needle-shaped portions as described above are provided, the tip is blade-shaped, or a screw groove is provided. It may be something like a fish.

It is desirable that at least a part of the leaching member, in particular, a hydrophilic porous body having continuous ventilation holes from the portion in contact with the electrolyte solution in the electrolyte solution reservoir to the portion in contact with the water absorbing member and the diffusing member. This is because the electrolyte solution absorbs water into the pore structure due to the capillary force and facilitates permeation into the leaching member.

Furthermore, it is desirable to provide a fixing means for preventing the leaching member from moving and damaging the partition wall before use. For example, in the case of the push-pin-shaped leaching member described above, the head (umbrella-shaped portion) of the leaching member is protruded from the outer surface of the support, and a stopper (stopper) that is detachable between the lower surface of the head and the outer surface of the support Should be provided. Further, by matching the shape of the stopper with the support, the stopper can also serve as a protective cover by covering the dropping hole and the terminal portion.

The diffusing member is for diffusing a part of the test solution dropped from above the ion-sensing electrode and bringing it into contact with the electrolyte solution leached by the leaching member, and one end thereof is the test solution. Is located at the drip part and the other end is arranged to be in contact with the leaching member. In this case, the end of the test solution on the dropping part side does not necessarily have to be in direct contact with the solid electrolyte surface, but when a certain amount of the test solution is dropped, part of the test solution is solid electrolyte. Any shape and arrangement that allows contact with In order to improve the permeation of the electrolyte solution, the diffusing member is preferably made of a hydrophilic porous body having continuous ventilation holes such as gauze and non-woven fabric. The diffusing member may be formed integrally with the leaching member.

Measurement of the ion concentration using the ion sensor constructed as described above is performed as follows. First, after connecting the respective terminal portions derived from the ion-sensing electrode and the reference electrode of the ion sensor to a potentiometer (for example, an electrometer), fixing the leaching member, if any, is provided. The state is released, and the leaching member is moved to damage or remove the partition wall of the reference electrode. For example, in the case of the push pin-shaped leaching member described above, remove the stopper and push in the head of the leaching member,
The needle portion of the leaching member is pierced into the partition. The electrolyte solution is leached while penetrating the porous body from the tip of the needle-shaped portion immersed in the electrolyte solution by penetrating the partition wall, and part of the leached electrolyte solution is a water-absorbing member on the reference electrode. Is also absorbed.

Thereafter, a predetermined amount of the test liquid is dropped from above the ion sensitive electrode (or in the vicinity of the ion sensitive electrode) to bring the solid electrolyte and the test liquid into contact with each other, and a part of them is moved inside the diffusion member. Diffuse and contact with the electrolyte solution,
Electrical conduction between the ion sensitive electrode and the reference electrode is secured, and the potential difference generated between the two electrodes is measured by the potential difference measuring device. The target ion concentration is determined from the obtained potential difference based on a calibration curve showing the relationship between the ion concentration and the potential difference, which has been prepared in advance using a reference solution having a known ion concentration.

[0026]

In the ion sensor of the present invention, both the ion-sensing electrode and the reference electrode are formed as solid electrodes, and the sensing member and the inner electrode are submerged in liquid like the conventional internal liquid type ion electrode and reference electrode. Since it is not stored in the state of being immersed in the electrolyte, even when a solid electrolyte having poor long-term storage stability in a wet state is used as a sensitive member or when the inner electrode of the reference electrode is miniaturized There is no concern about its deterioration over time. Then, when the ion concentration is measured, the water-absorbing member of the reference electrode absorbs the electrolyte solution by the action of the leaching member to bring it into contact with the inner electrode so that the reference electrode can function, and the reference electrode is placed above the ion-sensitive electrode. When the test solution is dropped, the test solution and the electrolyte solution come into contact with each other on the diffusion member in the vicinity of the reference electrode, and electrical conduction is established between the ion sensitive electrode and the reference electrode.

At this time, since the inner electrode of the reference electrode is immersed in the electrolyte solution having a constant concentration by the water absorbing member, a constant reference potential is generated, while the solid electrolyte of the ion-sensing electrode comes into contact with the test liquid. Therefore, an electric potential is generated according to the concentration of the ions to be measured in the test liquid. Therefore, the potential difference corresponding to the ion concentration is measured by measuring the potential difference generated between the two electrodes, and the ion concentration is obtained using a calibration curve that shows the relationship between the concentration and the potential difference created in advance.

[0028]

Embodiments of the present invention will be described below with reference to the drawings. A front view and a vertical sectional view of the ion sensor of the present invention are shown in FIGS. 1 and 2, respectively. The ion sensor 1 is mainly composed of a support substrate 2, an ion sensitive electrode 3, a reference electrode 4, a leaching member 7, an electrolyte solution reservoir 8, a diffusing member 9, a case 25 accommodating them, and a stopper 28. In this embodiment, the ion sensitive electrode is provided with a Na ion sensitive electrode 3a, a K ion sensitive electrode 3b, and a Cl ion sensitive electrode 3c, and is an ion sensor for measuring these three ion species. This ion sensor 1 was manufactured as follows.

First, a copper-clad laminate having one surface of a glass epoxy substrate covered with copper foil is etched to form three ion-sensitive electrode wirings 21a and 21 as shown in FIG.
b and 21c and one reference electrode wiring 21d were formed to obtain the support substrate 2. As shown in FIGS. 4 and 5, the ion sensitive member 30 is provided on one end of the ion sensitive electrode wirings 21a, 21b, 21c with a conductive bridge material 31 interposed therebetween.
Were mounted respectively to form the ion sensitive electrodes 3a, 3b and 3c.

The Na ion sensitive electrode 3a has an outer diameter of 2
mm disk-shaped NASICON ceramics with a thickness of 2 mm (N
The a ₃ Zr ₂ Si ₂ sintered PO ₁₂₎ and sensitive members, the K ion sensitive electrode 3b, the NASICON ceramics sintered body surface polyvinyl chloride containing valinomycin membrane (thickness 0.01 mm) The coated material is used as a sensitive member and Cl
For the ion-sensitive electrode 3c, a polyvinyl chloride film containing a tridodecylmethylammonium salt (thickness 0.01 mm)
Was used as the sensitive member. The vinyl chloride film contains a predetermined amount of o-nitrophenyl octyl ether as a plasticizer and potassium tetrakis (parachlorophenyl) borate as an anion removing agent. Also,
As the conductive bridge material 31, a conductive paste (Dotite: made of phenol resin containing carbon particles) is used.
FC-403R, manufactured by Fujikura Kasei Co., Ltd. is prepared, and a certain amount is applied to the surface of each of the sensitive members on the side of the support substrate, and then adhered to a predetermined position of the support substrate 2 to maintain the state. While conducting heat treatment at 150 ° C. for 30 minutes, the conductive paste was thermally cured to bond the ion sensitive member and the support substrate.

The tip portion 1 of the Ag wire having a diameter of 0.1 mm
0 mm in 0.1N hydrochloric acid under anodic polarization 0.4
By electrolyzing at a current density of mA / cm ² for 30 minutes, a silver chloride layer is formed on the surface of the Ag wire to form a silver / silver chloride electrode, and the silver / silver chloride electrode is formed at the other end of the reference electrode wiring 21.
The inner electrode 42 of the reference electrode 4 was soldered to d.

Next, as shown in FIGS. 6 and 7, through-holes 23a, 23b, 23c, 23d and 23e having the same size and position as the ion sensitive electrode, the reference electrode and the electrolyte solution reservoir are formed. A polycarbonate frame 23 having a thickness of 3 mm was adhered to the surface of the support substrate 2 on the electrode formation side with an epoxy adhesive. The through hole 23e serves to configure a recess surrounded by the through hole 23e and the support substrate as the electrolyte solution reservoir 8, and is formed so as to be positioned approximately in the middle between each ion sensitive electrode and the reference electrode. . The other end of each wire is connected to a terminal unit 22a, 22b, 2
It is exposed as 2c and 22d. Gauze was inserted as the water absorbent member 43 into the through hole 23d for the reference electrode. As the electrolyte solution 6 sealed in the electrolyte solution reservoir 8,
An AgCl-saturated KCl saturated aqueous solution was prepared, and this was injected into the through hole 23e.

Next, as shown in FIG. 8 and FIG.
A partition wall 5 made of a vinyl chloride film having a thickness of μm is adhered to the peripheral edge of the opening end of the through hole 23e by a thermal adhesion method to form an electrolyte solution 6
Was sealed to form an electrolyte solution reservoir 8. Then, a water-repellent fluororesin film (not shown) is coated so that only the upper parts of the electrode parts and the electrolyte solution storage part are exposed, and then, as shown in FIGS.
Through holes 23a, 23b, 23c, 23d, 23e
Was formed so as to cover the formation position of the, and the peripheral portion was fixed with an adhesive.

Next, as shown in FIGS. 12 and 13, a through hole having a diameter of 5 mm and a diameter of 1.2 mm are provided at predetermined positions of an acrylic resin case 25 for accommodating the support substrate 2 having the above-mentioned electrodes and the like formed therein. The through holes are provided as a dropping hole 26 for the test liquid and a through hole 27 for the needle-like portion of the leaching member 7, respectively. Then, the support substrate 2 was inserted into the case 25. Further, as shown in FIG. 2 described above, a needle-shaped portion 71 (diameter 1 mm, length 7 mm, porosity 35 made of porous alumina porcelain) is used.
%, The average pore diameter is 1.5 μm), one end of which is pointed and the other end is attached with an umbrella portion 72 having a diameter of 5 mm with an adhesive to form a leaching member 7. This is fitted into the through hole 27, and the case 2
A polyethylene stopper 28 was removably inserted into the gap between the No. 5 and the umbrella portion 72 and was temporarily fixed. The thickness of the stopper 28 is set so that it stops at a position where the tip of the needle-shaped portion 71 does not contact the partition wall 5.

Ten ion sensors 1 thus obtained were prepared and evaluated for response time, reproducibility of detected potential, variation among individuals, and ion concentration gradient. To measure the ion concentration, as shown in FIG. 14, first, the stopper 28 of the ion sensor 1 is removed, and the terminal portions 22a, 22b, 22.
c and 22d are electrometers (not shown)
Connected to. Next, the umbrella portion 72 of the leaching member 7 was pushed by a finger to penetrate the needle-shaped portion 71 into the diffusion member 9 and the partition wall 5 was broken, and the tip portion of the needle-shaped portion 71 was immersed in the electrolyte solution 6. Then, 100 μl of the test liquid is dropped into the dropping hole 26, and the potential difference between each of the ion sensitive electrodes 3a, 3b, 3c and the reference electrode 4 is measured at a temperature of 2 using an electrometer.
It was measured at 5 ° C.

As a test solution, Na ion concentration: 140 m
M, K ion concentration: 4 mM, Cl ion concentration: 100 m
A standard serum of M was used. The response time was the time from when the test liquid was dropped on the ion sensor until the detected potential showed a constant value. The reproducibility of the detection potential was obtained by repeating measurement with a solution to be measured having a constant ion concentration five times for one sensor, and using the shift amount from the center value of the detection potential. As the variation between individuals, the difference (maximum-minimum) when 10 sensors were measured under the same condition was used. The ion concentration gradient was calculated from a calibration curve prepared from the detection potential at a concentration of 10 to 1000 mM.

FIG. 15 shows the responsiveness to Na, K and Cl ions. About 30 for Na ion
Within seconds, the potentials of K and Cl ions were stable within about 1 minute. The reproducibility when repeatedly measured is ± 2 mV, the variation between individuals is about 4 mV, and the ion concentration gradient is 55.0 to 58.0 mV / d.
It was ecade. As is clear from these results, the response time of the ion sensor of the present invention is shorter than that of the conventional method, and it is confirmed that reproducibility and variation among individuals are at a practical level. It was Also,
The ion concentration gradient was also comparable to that of the conventional method and was good.

[0038]

As described above, the ion sensor of the present invention has a configuration in which the solid ion sensitive electrode and the reference electrode are integrated as described above, so that the solid electrolyte, which is the sensitive member of the ion sensitive electrode, is in a dry state. It is possible to stably store it in, and it is possible to suppress the change with time of the reference electrode and the internal liquid (electrolyte solution). Further, during use, the reference potential generated by the reference electrode can be stabilized as in the conventional internal liquid type. As a result, the response time (the time until the detected potential stabilizes) is shortened, the reproducibility of the detected potential is improved,
Variations in the detected potential among the individual sensors are reduced, and the ion concentration gradient of the detected potential is the theoretical value of the Nernst law (59.2).
(MV / decade: 25 ° C.), which has the effect of enabling measurement with high measurement accuracy close to that of a simple operation.

[Brief description of the drawings]

FIG. 1 is a front view of an ion sensor of the present invention.

FIG. 2 is a sectional view of the ion sensor of the present invention.

FIG. 3 is a front view of a support substrate on which wiring is formed.

FIG. 4 is a front view showing a state in which a sensitive member and a reference electrode are formed on a support substrate.

5 is a cross-sectional view taken along the line AA of FIG.

FIG. 6 is a front view showing a state in which a frame body is attached.

7 is a sectional view taken along the line BB of FIG.

FIG. 8 is a front view showing a state in which a partition is attached.

9 is a cross-sectional view taken along the line CC of FIG.

FIG. 10 is a front view showing a state in which a diffusion member is attached.

11 is a cross-sectional view taken along the line DD of FIG.

FIG. 12 is a front view showing a state of being inserted into a case.

13 is a cross-sectional view taken along the line EE of FIG.

FIG. 14 is a sectional view for explaining a state when the ion sensor of the present invention is used.

FIG. 15 is a graph showing the responsiveness of the ion sensor of the present invention.

[Explanation of symbols]

1 Ion Sensor 7 Leaching Member 2 Support Substrate 8 Electrolyte Solution Reservoir 3a, 3b, 3c Ion Sensing Electrode 9 Diffusing Member 4 Reference Electrode 25 Case 5 Partition Wall 28 Stopper 6 Electrolyte Solution

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiko Okuyama 14-18 Takatsuji-cho, Mizuho-ku, Nagoya City Nippon Special Ceramics Co., Ltd. (72) Naoko Horibe 14-18 Takatsuji-cho, Mizuho-ku, Nagoya City Japan Special Ceramics Within the corporation

Claims (15)

[Claims] 1. An electrolyte solution is enclosed by a solid ion-sensing electrode using a solid electrolyte, a solid reference electrode having a water-absorbing member on the inner electrode, and a partition that is at least partially damaged or removable. Electrolyte solution reservoir, movable leaching member for leaching electrolyte solution from the electrolyte solution reservoir by damaging or removing the partition wall, and electrolyte leached by the leaching member by diffusing the dropped test liquid An ion sensor, comprising: a diffusing member for contacting with a solution. 2. The water-repellent film according to claim 1, wherein a part of the leaching member has a needle-shaped portion, and a part of the partition wall is made of a water resistant film into which the needle-shaped portion can be inserted. Ion sensor. 3. The ion sensor according to claim 2, wherein the needle-shaped portion is made of a hydrophilic porous body having continuous ventilation holes. 4. The ion sensor according to claim 1, wherein the leaching member includes fixing means for preventing the partition wall from being damaged or removed before use. 5. The ion sensor according to claim 1, wherein the diffusion member is made of a hydrophilic porous body having continuous ventilation holes. 6. The ion sensor according to claim 1, wherein the leaching member and the diffusing member are integrally formed. 7. The ion sensor according to claim 1, further comprising a plurality of ion sensitive electrodes using a solid electrolyte that selectively responds to different ion species. 8. The ion sensor according to claim 1, wherein the solid electrolyte is made of ceramics. 9. A solid ion-sensing electrode using a solid electrolyte, a solid reference electrode having a water-absorbing member on an inner electrode, an electrolyte solution reservoir in which an electrolyte solution is sealed by a partition wall, and the partition wall. A movable leaching member for leaching the electrolyte solution from the electrolyte solution reservoir after being damaged or removed, and a diffusing member for diffusing the dropped test liquid and bringing it into contact with the electrolyte solution leached by the leaching member. An ion concentration measuring method using an ion sensor comprising:
After the partition wall is broken or removed by the operation of the leaching member to leaching the electrolyte solution, the water-absorbing member is caused to absorb part of the leached electrolyte solution, and the inner electrode is brought into contact with the electrolyte solution. A test liquid is dropped from above, and while contacting with the solid electrolyte by diffusing in the diffusion member, a part thereof is also contacted with the electrolyte solution leached by the leaching member, and the ion sensitive electrode and the reference electrode. An ion concentration measuring method characterized by measuring a potential difference generated between the two. 10. A part of the leaching member has a needle-shaped portion, and a part of the partition wall is made of a water resistant film into which the needle-shaped part can be inserted. The ion concentration measuring method according to claim 9, wherein the electrolyte solution is leached out by damaging or removing it by press-fitting. 11. The ion concentration measuring method according to claim 10, wherein the needle-shaped portion is made of a hydrophilic porous body having continuous ventilation holes, and the electrolyte solution is leached out through the continuous ventilation holes. 12. The ion concentration measuring method according to claim 9, wherein the diffusion member is made of a hydrophilic porous body having continuous ventilation holes. 13. The ion concentration measuring method according to claim 9, wherein the leaching member and the diffusing member are integrally formed. 14. The ion sensor comprises a plurality of ion-sensing electrodes using a solid electrolyte that selectively responds to different ion species, and simultaneously measures the ion concentrations of the plurality of ion species. The ion concentration measuring method according to claim 9. 15. The ion concentration measuring method according to claim 9, wherein the solid electrolyte is made of ceramics.