JPS58193449A - Ion activity meter - Google Patents

Abstract

PURPOSE:To attain a stable characteristic with a very simple method by a meter wherein metal layers laminated on an insulating support is divided longitudinally and transversely by scratched grooves to form a group of electrodes comprising a plurality of independent segments which are electrically insulated from one another. CONSTITUTION:A metal layer 2 formed on an insulating support 1 is divided into two parts 2a and 2b in a paired structure by a groove 11-a scratched in a longitudinal direction. With parts of both side ends of the metal layer 2 being masked in a longitudinal direction, a water-soluble layer 3 comprising salt of the metal and an ion selection layer 5 are formed thereon. Metal layers are exposed at both side ends of the metal layer 2 to constitute electric connection terminals 6. On the ion selection layer 5, a bridge 19 formed of a porous member 8 after being subjected to the insulating treatment is adhered through a water non- permeable supporting layer 7 partially including holes.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an instrument for measuring ion concentration or ion activity (hereinafter referred to only as ion activity). In particular, the present invention comprises a plurality of film-like ion-selective electrodes (hereinafter simply referred to as ion-selective electrodes) for potentiometrically measuring ion concentrations in body fluids such as aqueous fluids, blood, and serum. It relates to something with a structure.

The ion activity measuring device of the present invention has a similar structure to what is generally called a half cell or a PH electrode.

Generally, Na, Ga2, C6θ, HCO in biological fluids
Methods using wet ion-selective electrodes to measure the concentration of inorganic ions such as 30 are widely practiced.

However, the wet method uses a needle-shaped electrode immersed in biological fluid for measurement, and there are some drawbacks to managing the electrode in terms of maintenance, cleaning, conditioning, lifespan, damage, etc. Since it is necessary to fully immerse the sample in the test liquid in the cup each time, a large amount of test liquid is required. Therefore, in view of the drawbacks of the wet method, an ion-selective electrode in which the electrode is made of a dry film is known.
No. 2584 and US Pat. No. 4,053,381. As shown in Figure 1, this electrode film consists of an insulating support 1, a metal layer 2, a water-insoluble salt layer of the same type of metal as the metal of the metal layer, and a water-soluble salt layer having a common anion with the water-insoluble salt. A dried reference electrolyte layer 4 consisting of a hydrophilic binder matrix containing dissolved salts and an ion-selective layer 5f.
It has a four-layer laminated structure with IK lamination. Also, excluding the reference electrolyte layer 4; +11 layer stack structure 1 & film is disclosed in Japanese Patent Application Laid-Open No. 17851/1985, and furthermore, both the water-insoluble salt layer and the reference electrolyte layer are omitted, and ion exchange is performed directly on the metal layer. JP-A-48-82897 discloses an electrode having a two-layer laminated structure provided with an ion selective layer containing a substance. To measure ion activity with these electrode films,
As shown in FIG. 2, two film-like electrodes 10 made of the various laminated structures described above are arranged side by side to form a paired structure, connected by a bridge 19 to be described later, and a potentiometer 20 is connected to this electrode pair. 15 and the standard solution 16 are placed on the electrode film through the bridge 19 in minute amounts (for example, 5AA' to 5
0μl) to create an ion flow between the test solution and the standard solution,
Measures the potential difference that occurs between electrodes. However, with dry type ion-selective electrodes such as ion-selective electrodes, the ion activity is read as the differential potential between the test solution and the standard solution generated between the counter electrodes, so each counter electrode has an electrochemical It is important that the physical properties are the same. However, in general, it is nearly impossible for individually manufactured electrodes to have exactly the same physical properties, and it is best to approximate them as much as possible. The advantage of using a counter electrode is that each electrode can be physically separated, which is advantageous in achieving electrical insulation between the electrodes.However, another problem is that the electrode composition layer (at least a metal If the edges (hereinafter referred to as edges) of the layer (hereinafter referred to as edges) ooze out, this may cause undesirable defects in the measurement of ion activity.

That is, when the above-mentioned electrode film K, test liquid, and standard liquid are each spotted, the deposited droplets are separated by the ion selective layer (or the protective layer described later) of each electrode film. in some cases, it tends to spread over the surface of the protective layer). The liquid that spreads out is the edge of the electrode film.
This flowing liquid shorts out the various constituent layers of the electrode. Therefore, an incorrect potential will occur due to a short circuit, or the potential will become zero due to a short circuit, giving an erroneous potentiometer reading. Therefore, it was essential for the electrode film to prevent such iodine from occurring due to the test liquid or standard liquid.

Based on this recognition, Japanese Patent Application Laid-Open No. 52-142584
In order to expose only the ion-selective layer of the electrode film and prevent water from penetrating into other parts, the electrode film is housed in a frame made of an electrically insulating material that is permeable to the water valve, such as plastic. Anti-shorting measures had to be taken to prevent short circuits between the layers, such as by providing measurement cells or strips of adhesive.

However, these anti-shorting means also require processing for each electrode film, which requires a lot of manpower and is difficult to process, making it difficult to achieve complete anti-shorting. Understood.

Furthermore, as can be seen from what has been described above, these ion-selective electrodes are disposable devices for each test liquid, and therefore, one ion-selective electrode is used each time the test liquid is measured in
The measuring cell must be disconnected from the potentiometer leads 21 and 22 and discarded. Therefore, the leads 21 and 22 of the potentiometer 20 must be connected to the electrodes of the measurement cell for each measurement of each test liquid, and the contact resistance between the lead wires and the electrodes for each measurement is therefore reduced. Measurement errors caused by changes and variations became a problem, and it was time-consuming to reconnect the potentiometer for each measurement.

The inventors of the present invention have been conducting intensive research in order to eliminate the drawbacks of these known techniques, but first they filed a patent application No. 56-0089.
No. 88, No. 18, which has a plurality of dry bridges made of two or more elongated solid electrodes and a porous member each having one common electrical connection terminal at or near one end in the longitudinal direction. We proposed an ion activity measuring device consisting of a group of electrodes.

One embodiment of the invention will be further explained with reference to FIG.
Figure -a is a plan view showing the ion activity measuring instrument according to the invention, which includes a long solid electrode filter 0 for standard solution and a long solid electrode 51 for test solution.
form a pair, one end of each electrode is coated with a metal layer 2,
A common electrical connection terminal portion 34 is formed, and the common terminal portion 34
are connected to the leads 21 and 22 of the potentiometer 20 via probes 32, respectively. The elongated solid electrodes 30 and 31ii are elongated versions of the previously known film-like electrodes mentioned above.

In this case, the length can be arbitrarily set within a range where the electrical resistance of the film electrode does not affect the measured value. A plurality of ladder-like bridges 19 are provided on the pair of elongated solid electrodes 50 and the filter 1 as shown in the figure. In these plurality of bridges 19, sufficient distance should be provided between adjacent bridges to prevent contamination due to seepage of the test solution or standard solution, or each bridge should be separated from the test solution or standard solution. It is desirable to ensure that the standard solution does not spill out.

In the ion activation IT measurement device configured as described above, the potentiometer 20 is still connected to the common terminal portion 34 via the probe 32 without requiring the insulation treatment for each individual electrode pair as described above. Therefore, there is no need to reconnect the potentiometer for each measurement, saving time and providing stable measurement results. However, since the connection is made through a common terminal, the used bridge 19 must be discarded every time one measurement is completed, as shown in FIG. 6D. The next measurement of ion #degree or ion activity is performed by using a new bridge 19 that was adjacent to the truncated bridge 19 and performing the same operation. However, even with such an ion activity measurement device consisting of a Km number bridge, the problem of the above-mentioned variation in physical properties has remained pending since the individually manufactured electrodes are later made into a paired structure.

Therefore, the present inventors have already made individual inventions that do not cause variations in physical properties and also provide electrical insulation between electrodes. In Japanese Patent Application No. 56-108979, it was discovered that by covering the conductive layer with an ion-selective layer, there was no need for special anti-shortening means, and that a single We proposed an ion-selective electrode in which a tJI pole pair is formed from the a pole (Japanese Patent Application No. 57-40598).

According to each of the above-mentioned inventions, after forming the metal layer on the common support and before forming the outermost layer (ion selective layer or protective layer), at least the metal layer is scratched. Thus, a 'turquoise pair having the same physical properties was easily formed, and sufficient electrical insulation was also obtained.

However, in order to further complete the insulation, the above-mentioned water-insoluble metal salt layer and ion selective layer are provided on the metal layer after grooves are formed in the metal layer. That is, as shown in FIG. 4, the exposed portion of the metal layer 2 provided on the insulating film substrate 1, including the edges formed during cutting, is covered with a water-insoluble metal salt layer 5 having high electrical resistance. has been done. Therefore, the metal layer 2 which is physically separated by the grooves 11 to achieve insulation is further enhanced by the water-insoluble metal salt layer. Moreover, as a result of coating the ion selective layer 5 thereon, the metal layer 2 is perfectly protected from unexpected flowing liquid, and there is no possibility of short circuits or the like occurring.

The present inventors have completed the present invention based on the above-mentioned inventions, and have been able to provide a low-cost ion activity measuring instrument that provides stable characteristics using an extremely simple method.

That is, the present invention provides an ion activity measuring device comprising a selective electrode in which at least a metal layer and an ion selective layer are laminated on an electrically insulating support, in which at least the metal layer has grooves scratched vertically and horizontally. This is an ion activity measuring instrument characterized by comprising a plurality of independent electrode groups, each piece of which is electrically insulated. One aspect of the present invention is the ion activity measuring instrument having the above structure, in which a layer made of a water-insoluble salt of the same kind of metal as the metal of the metal layer is laminated between the metal layer and the ion selection layer. In another aspect, a layer made of a water-insoluble salt of the same kind of metal as the metal of the metal layer and a reference electrolyte layer are laminated between the metal layer and the ion selection layer, and the ion activity measuring device having the above structure comprises: It is. A specific example of the present invention is an ion activity measuring instrument having any of the above configurations in which the scratched groove reaches a part of the electrically insulating support, and another specific example is an ion activity measuring instrument in which the scratched groove reaches a part of the electrically insulating support. The ion activity measuring instrument corresponds to any of the above configurations in which the grooves are provided by scratching on the layer immediately before it is formed.

Hereinafter, the present invention will be explained in more detail with reference to the drawings.

Fig. 5 is a diagram showing one embodiment of the present invention, Fig. 5a is a plan view thereof, Fig. 5b is a partial sectional view taken along line AA' in Fig. 5a, and Fig. 5C is a perspective view. show. 1 is an electrically insulating support, 2 is a metal layer provided on the electrically insulating support, and the metal layer 2 is divided into portions 2a and 2b by grooves 11-a scratched in the longitudinal direction, forming a paired structure. The metal layer 2 further forms a plurality of independent electrode pairs by grooves 11-b intersecting in the longitudinal direction. Furthermore, both end faces of the metal layer 2 are partially masked in the longitudinal direction to provide a water-insoluble salt layer 3 and an ion selection layer 5 of the metal. Both end faces of the metal layer 2 are exposed as electrical connection terminal portions 6 . A bridge 19 made of a porous member 8 is placed on the ion selective layer 5 via a water-impermeable support layer 7 having some holes.
are insulated and bonded together. In this embodiment, a configuration example is described in which both ends of the metal layer 2 are masked from the electrode structure layer further laminated on the metal layer, and the metal layer 2 is exposed to form the electrical connection terminal portion 6. It is also possible to have a structure in which the needle-shaped a) tq gas contactor is passed through the outermost layer of the ion selection electrode having the same structure and comes into contact with the metal layer, without providing an electrical connection terminal part.

When measuring ion activity using the ion-selective electrode configured as described above, the glued terminal of the potentiometer 20 is used as a needle-like contact terminal, and the electrical connection terminal portions 6 provided on both end faces of the metal layer are connected to each other. After making contact, the standard solution and the test solution are respectively placed in the holes 17 and 18 provided in the bridge 19 in the same manner as described above, and both solutions spread into the bridge. The ion activity is measured from the potential difference indicated by the potentiometer 20 after the tip of the liquid comes into contact with the tip. When the 16411 measurement is completed, the potentiometer is reconnected to other unused electrodes, and repeated measurements can be carried out in the same manner.

The present invention is composed of a plurality of electrode groups similar to the above-mentioned Japanese Patent Application No. 56-008988, but in the present invention, adjacent electrode pairs are completely insulated by grooves 11-b, and between adjacent bridges. Contamination caused by leakage of the test solution or standard H solution is also prevented, and there is no need to separate used electrodes one by one, and the electrodes located farthest from the common terminal must be used sequentially. There is no restriction on not being able to do so. This invention has the advantage that it is not necessary to reconnect the potentiometer each time a measurement is made since the electrical connection terminal portion is common.
In the present invention, electrodes of arbitrary length are formed in a cassette shape, and the lead terminal of a potentiometer contacts the electrical connection terminal and slides 9, or by using a dial type contact, there is no need to reconnect. Stable measurements are possible.

Further, in the invention, the length of the electrode in the longitudinal direction is limited to a range in which the internal resistance of the electrode does not have an influence, but this problem does not occur in the invention.

In the present invention, the metal layer is insulated by providing the groove, resulting in an electrode pair having the same physical properties. This groove is most commonly created by a scribing operation as described below, so it is usually a V groove as shown in Figure 5.
Takes the shape of a mold. First, by adopting a process in which grooves are formed in the metal layer when it is provided on the support, and then the water-insoluble metal salt layer and the ion selection electrode 1- are formed, unlike conventional ion selection electrodes, grooves are formed in the metal layer. The exposed edge that would be caused by the cutting operation during formation is not formed.

It is sufficient for the insulation between the metal layers 11 to be separated by a single groove, but for more complete insulation, two or more grooves may be used. In addition, there is a slight possibility that the liquid flowing down from the other end by spreading outside the space between the metal layers 11, which has the highest risk of conduction, in the direction opposite to the direction of the ion flow (i.e., outward) and flowing down from the other end may cause a short circuit. The end is adhesive) IJ
This can be dealt with by installing a tsupus, etc.

The method for manufacturing an ion selective electrode according to the present invention is as follows:
It can be made by the same means as disclosed in Japanese Patent Publication No. 40398). That is, a suitable support, for example a glass plate,
A conductive metal thin layer is provided on a ceramic plate, polymer material notebook or film, paper, etc. Conventionally known methods can be applied to form the thin layer. For example, a vapor deposition method, an electroless plating method, etc. are used. After forming a thin metal layer on the support, the metal layer can be reliably electrically insulated and separated by cutting the metal layer vertically and horizontally with a sharp edge such as a knife or scribing needle, as shown in Figure 5. . In one embodiment of the present invention, it is preferable that scratches be performed deep enough to reach the insulating support so that the scratches are not affected by chips of the metal layer or continuous layers stacked on the metal layer. Usually, it is preferable to scratch to a depth of 10 times or more the thickness of the metal layer, for example, the metal layer is scratched to a depth of 500
nm, when the support is 100 μm to 200 μm thick,
The appropriate depth of the scratch on the support is 5 μm to 50 μm. Methods of masking both end surfaces of the metal layer as electrical connection terminals include a known method of applying a resist and masking, and rResaarch Disclosure.
e Method of masking by applying a liquid resist that can be removed with alkali as disclosed in J Magazine 19445 (June 1980 issue), thickness of nickel or chromium as disclosed in Japanese Patent Application Laid-Open No. 56-63537 5nm to 20
A method of masking by depositing a thin film of 1.5 nm to 1i5 nm in palladium thickness.
or 3 nm to 20 nL of indium [
A method of masking by providing a vapor-deposited thin film of I, a liquid resist having film-forming ability and film removability after drying, for example,
Freon mask ■ (liquid resist whose main component is polyvinyl chloride, manufactured by Furuto Sangyo) is used. The metal layer provided with scratch grooves and masked with electrical connection terminals is replaced with a water-insoluble salt of the metal, or a layer of water-insoluble salt of the metal is placed on top of the metal layer and optionally A water-insoluble metal salt is contacted with an electrolyte, ie a solution containing an anion of said metal salt, to form an internal reference electrode. This water-insoluble salt is typically a metal halide of the metal layer, such as AgCj, Hg2CI2, etc., and is treated by a well-known method such as oxidizing the metal layer (and if the oxidizing agent does not contain halaibion). coated or treated with a composition containing ion). The oxidizing agent can be applied to the silver by conventional methods such as roll coating, dipping, lamination or plastic coating. The oxidizing agent can be present in a solution such as an oxidizing agent-containing acid solution (eg, hydrochloric acid).

Useful compensators include KCrOC1, 3 (Fe(3+)
(ON)6], K M n O4, K2Cr20□, N
H4VO3, (N F(4) 2 (Ce (4+)
(N03)a], and Fe(3+)2(OO
C-Coo) 3. The preferred oxidizing agent is KCrO
3CA', 2Cr20□ and K 3 (F e (3
+)(ON>, ). Combinations of oxidizing agents can also be used. CHandbook of C
hemistry and physics J, 50
th Edition The Chemical Ru
bber Company, published in 1969, No. D10
Further details regarding oxidizing agents useful in the present invention are provided on pages 9-114.

The amount of oxidizing agent used is variable depending on the thickness of the silver halide layer produced, but preferably the applied weight is 0.01
~2.05'/m2. The silver halogenide to be formed as a silver halogenide layer includes silver chloride, silver bromide, and silver iodide. It can be produced by folded electrolysis, or by dipping the silver layer as a wire, foil or supported thin layer into molten silver rhodanide. Further, according to Japanese Patent Application Laid-Open No. 52-142584, another aspect is disclosed. That is, useful metal/metal salt (%A g /'A gX ;

A useful silver layer capable of overcoating the silver halide layer as described above was prepared as follows.

Specifically, a layer of a fine-grained silver chloride-gelatin emulsion was coated on a polyethylene terephthalate support by conventional photographic film manufacturing techniques with a coverage of 2.02 g/m'' of silver as silver chloride and 95 Iil of gelatin/m2.

The silver chloride layer was then processed using Kodak Develop.
Developed in a standard black and white developer known as rD-19 for 5 minutes under room temperature sunlight conditions. After this layer was sufficiently washed with water and dried, it was overcoated with a silver chloride emulsion as described above. If necessary, a reference electrolyte layer for potential stabilization can be provided by a conventionally known method on the electrode film halogenated by any of these methods.

Regarding the formation of the reference electrolyte layer, see JP-A-52-1425.
No. 84, U.S. Pat. No. 4,214,968, and Japanese Patent Application Laid-Open No. 57-17852 can be used. The ion selective layer can select specific ions, and this ion selective layer can also be provided by a conventionally known method. For example, an ion carrier dissolved in a solvent is applied to a binder solution and dried. The ion carrier concentration is generally between 0.05y and 109/m2
, the thickness of the ion-selective layer is about 6 μm to about 125 μm, preferably 5 μm to 50 μm.

In the ion-selective electrode of the present invention, both the test liquid and the standard liquid are aqueous liquids, so the ion-selective layer must be water-insoluble. The ion selective layer may be hydrophilic or hydrophobic as long as it is water insoluble, but is preferably hydrophobic.

The materials constituting the ion selective electrode according to the present invention include:
The same materials used in electrodes known in the art can be used.

First, examples of conductive metals preferably used in the metal layer of the ion-selective electrode of the present invention include silver, platinum, palladium, gold, nickel, copper, aluminum, and indium, which are disclosed in the above-mentioned patent specifications. There is.

When the conductive layer is used as a foil, film, or thin layer on a support, a thickness in the range of about 50 nm to about 50 μm is generally desirable. There are no particular restrictions on the material used as the support, as long as it can support other parts of the electrode and is electrically insulating and electrically inert. It is possible to select and use known materials. Preferred are those constructed from film-forming polymers such as cellulose acetate, polyethylene terephthalate, polycarbonate, and polystyrene. The support generally has a thickness of about 0.05 to 0.5
It is desirable to form it to a thickness of m.

The most typical ion-selective layer consists of an ion carrier, an ion carrier solvent, and a hydrophobic organic binder (or a matrix of hydrophobic organic binders). Ion carriers include palinomycin, cyclic polyether, tetralactone, macroliviactin, enninatine group, monensins, gramicidins, nonactin group, tetraphenylborate,
There are cyclic polyhaptates 9 and the like.

Ion carrier solvents include promophenylnoenyl ether, 3-methoxyphenylphenyl ether, 4
-methoxyphenyl phenyl ether, dimethyl phthalate, dibutyl phthalate, dioctyl phthalate, dioctyl phenyl phosphate, bis(2-ethylhexynol) 7-talate, octyl diphenyl phosphate,
Examples include tritolyl phosphate and dibutyl sepacate.

The hydrophobic binder may be a hydrophobic natural or synthetic polymer capable of forming a thin film, such as cellulose ester,
Examples include polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile, polyurethane, polycarbonate, vinyl chloride, and vinyl acetate copolymer.

Ion carriers, ion carrier solvents, hydrophobic organic binders, and ion selective layers comprising them are described in Japanese Patent Application Laid-Open No. 52-142584 and US Pat. No. 40'53381.
Substances and techniques described in the specifications of No. 4171246, No. 4214968, and "Research Dlsclosurej Magazine Report No. 416113 (September 1977 issue) can be used.

Ion exchangers can also be used as materials for the ion-selective layer. When using an ion exchanger, ion conversion results in measuring the potentiometric response caused by changes in ion activity in the ion-containing solution.

The ion exchanger may be either cationic or anionic. Suitable ion exchangers that can be used in the present invention and the formation of ion-selective layers using them are disclosed in Japanese Patent Application Laid-Open No.
82897 (Japanese Patent Publication No. 52-47717).

In addition, regarding the ion selective layer, the ion to be measured,
K■, 5a (-9, Ca2■, Hco3Of7) m combination K
Although it is essential, the ion selective layer is not recommended when the ion to be measured is Gtθ and the electrode is composed of silver as the metal layer and silver chloride as the water-insoluble metal salt layer. . As an alternative, cellulose ester (
For example, TTF, cellulose acetate butyrate, cellulose acetate propionate, hydrolyzed cellulose acetate butyrate, etc., and mixed esters thereof)
Substances described in JP-A-55-89741 such as JP-A-55-89741;
A layer formed from the latex described in No. 3-72622 or No. 54-1684 may be provided as a protective layer permeable to ions to be tested. In this specification, this analyte ion permeable protective layer is also included in the ion selective layer.

It is also possible to use a bridge made of a conventional three-layer trilaminate; A member with no upper layer can also be used. For example, mixed paper made from synthetic polymer fiber Zelup and vegetable natural fiber pulp, paper made from synthetic polymer fiber Zelup, blended fabric made from synthetic polymer fiber and vegetable natural fiber, and vegetable-based paper. A sheet made from a plain fabric made of natural fibers, a membrane filter made of cellulose ester or regenerated cellulose with an average pore diameter of 2 am or less, a membrane filter containing nitrocellulose and an average pore diameter of 10 μm or less, and a pulp made of vegetable natural fibers and compressed. It's paper. Furthermore, things like nylon thread can also be used effectively.

In the ion-selective electrode of the present invention, by simply scratching, continuous metal layers having the same physical properties can be easily formed into a pair of insulated metal layers, and by performing multiple scratches, a pair of metal layers can be formed. A plurality of sets of metal layers can be formed, and a plurality of independent and continuous ion-selective electrode groups can be easily formed by applying oxidation/halogenation treatment and laminating an ion-selective layer or a protective layer. .

Ion-selective electrodes made of such electrode groups have uniform physical properties, are easy to handle, and have advantages such as a simple manufacturing process and low cost. In the above description, scratching was performed immediately after the formation of the metal layer, and the edges caused by the scratching were insulated with the metal halide layer provided on top of the scratching.
In other embodiments, scratching may be performed to separate the metal layer before forming the outermost layer, that is, immediately after laminating the rogenated metal layer or the electrolyte layer. In still another embodiment, the metal layer may be separated by scratching from above the outermost layer after the outermost layer is formed. However, in this case, it is desirable to take measures to prevent so-called external bridging, in which the dropped liquid overflows the surface of the porous member.

The manufacturing of the ion selective electrode of the present invention has been described in which it is made from a long insulating support, but it is formed by cutting each electrode pair from a rectangular support in which long supports are arranged horizontally. You can also. In addition, in the above description, electrodes with a four-layer or three-layer Fi layered structure were described, but
A two-layer laminated electrode consisting of a metal layer and an ion selective layer as disclosed in Japanese Patent No. 97 can also be used.

[Brief explanation of the drawing]

Figure 1 shows an ion-selective electrode with a four-layer stacked structure.
Fig. 2 is an explanatory diagram showing a method for measuring ion activity; Fig. 3 is a plan view of an ion activity measuring instrument previously proposed by the present inventor and explains how to use it. A plan view, FIG. 4 is a cross-sectional view of the ion selective electrode showing the state due to scratches, FIG. 5a is a plan view showing one embodiment of the present invention, and FIG. 5b is a partial cross-sectional view taken along the line AA'. FIG. 5C is a perspective view thereof. DESCRIPTION OF SYMBOLS 1... Electric insulating support body, 2... Metal layer, 6...
Water-insoluble metal salt layer, 4... Electrolyte layer, 5... Ion selection layer, 6... Electrical connection terminal portion, 7... Water-impermeable support layer, 8... Porous member, 10 ...Ion selective electrode, 11...Groove, 15...Test liquid,
16...Standard solution, 17.18...Liquid spotting hole, 19...Bridge, 20...Potentiometer Fig. 1 Fig. 2 Fig. 7 II 3. a Figure 3-b Figure 114

Claims (5)

[Claims] (1) In an ion activity measurement device comprising an ion selective electrode in which at least a metal layer and an ion selective layer are laminated on an electrically insulating support, at least the metal layer is divided by grooves scratched vertically and horizontally, and each An ion activity measuring instrument characterized by comprising a plurality of independent electrode groups whose pieces are electrically insulated. (2) The ion activity measuring device according to claim 1, wherein a layer made of a water-insoluble salt of the same kind of metal as the metal of the metal layer is laminated between the metal layer and the ion selection layer. (3) The ion active device according to claim 1, wherein a layer made of a water-insoluble salt of the same kind of metal as the metal of the metal layer and a reference electrolyte layer are laminated between the metal layer and the ion selection layer. Quantity measuring instruments. (4) The ion activity measuring instrument according to any one of claims 1 to 3, wherein the groove reaches a part of the electrically insulating support. (5) The ion activity measuring instrument according to any one of claims 1 to 6, wherein the grooves are provided by scratching on the outermost layer immediately before the outermost layer is formed.