JP3350812B2 - Ion sensor, ion sensor plate, and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion sensor for various kinds of ions for examining blood and the like, and more particularly to a disposable simple ion sensor plate which is a component thereof, which is used in an interface between an ion sensitive membrane and a silver / silver halide electrode. The present invention relates to a device in which electric resistance is reduced.

[0002]

2. Description of the Related Art Disposable simple inspection ion sensor plates have been developed, and several ion sensor plates have been proposed. The one differential-type multi-ion sensor connects a multi-ion sensor plate to a measurement circuit and measures a number of different ion concentrations at the same time, and the multi-ion sensor plate has, as shown in FIG. Five pairs of a pair of sample liquid measurement electrodes 2a and a reference electrode 2b in which electrolytic silver plating is applied to a copper electrode formed by etching on a glass epoxy substrate 1 are provided as a set, and silver plating is performed on opposite ends of each electrode. Silver chloride layer 4 on top of the layer
a, 4b, a multi-ion sensor plate main body 5 having external electrodes on the ends of the electrodes facing away from each other, and through holes 6a to 6e, 6 communicating with the respective sets of silver chloride layers 4a, 4b. 'a to 6'e, a liquid junction 7 of an elongated hole for bringing the sample liquid and the reference liquid into contact with each other at the tips of two flow paths of the upper cell described later, and the above-mentioned set of electrodes 2a, 2b. A bank 9 made of a polyester film having communicating holes 8a and 8b is joined to the multi-ion sensor plate body 5. The respective through holes 6a to 6e of the embankment body 9,
Various ion-sensitive membrane solutions each containing an ion-sensitive substance of various ions such as a macrocyclic compound called ionophore or an ion-exchange resin are dropped through 6′a to 6′e,
By drying and forming ion-sensitive films on the silver chloride layers 4a and 4b, a total of five different ion-sensitive films are provided. The joined body of the multi-ion sensor plate body 5 and the bank body 9 is inserted into the concave portions 10a and 10b of the lower cell 10 made of a transparent acrylic resin plate, and the upper cell 12 made of a transparent acrylic resin is attached to the lower cell 10 with a double-sided adhesive tape. And the above joined body is mounted. The upper cell 12 is provided on the back surface of the transparent plate with flow passages 13 and 14 formed of concave grooves communicating with the through holes 6a to 6e and 6'a to 6'e, divided into two by partition walls, and one end of each flow passage. Has a sample liquid inlet 1
5. In addition to the provision of the reference liquid inlet 16, air vent grooves 13 a, 14 a formed of narrow concave grooves communicating with the flow passages are provided at the other ends of the respective flow passages in an L-shape, respectively, and symmetrically arranged. The tip is a sample liquid inlet 15 and a reference liquid inlet 16
A terminal insertion hole for communicating with a vertical hole 13b, 14b provided at the tip of the sampler, and for inserting a terminal of a measuring instrument (not shown) corresponding to the exposed end of the external electrode of the sample liquid measurement electrode 2a and the reference electrode 2b. 18a and 18b are provided.

When a multi-ion sensor plate having such a structure is used, a sample liquid and a reference liquid are injected into a sample liquid input section 15 and a reference liquid input section 16 by a syringe or the like, respectively. Liquid is circulated,
While being supplied to the ion-selective electrodes in the through holes 6a to 6e and 6'a to 6'e, the sample liquid and the reference liquid come into contact at the liquid junction 7. In this state, insert the terminal of the measuring instrument into the terminal insertion hole 1
The ionic components of the sample solution are measured by inserting the sample solution into each of the external electrodes 8a and 18b, and the concentrations of a total of five types of ions are measured by one injection of the sample solution and the reference solution.

[0004]

When an ion-sensitive film is formed on an Ag / AgX electrode such as such a silver / silver chloride electrode, the potential at the interface between the ion-sensitive film and the AgX layer is stabilized, and to improve the accuracy of the detection value of the ion sensor, AgX in AgX layer = Ag ^{+ +} Cl ^-
It is necessary to stabilize the dissociation equilibrium of the compound, and it has been proposed in a previous application (Japanese Patent Application No. 9-367808) to include a stabilizing substance in the ion-sensitive membrane for the stabilization. However, even when the resistance at the interface with the AgX layer contacted by the ion-sensitive film is high, the current flowing in the measurement circuit and the voltage generated by the electrical resistance at the interface easily affect the output of the multi-ion sensor, This has an adverse effect on the accuracy of the detected value by the output, and thus on the measurement accuracy of the ion concentration converted from the detected value. Ion sensitive membrane and AgX
Methods for lowering the electrical resistance at the interface with the layer include increasing the contact area between the ion-sensitive membrane and the AgX layer;
The electrical resistance of the gX layer may be reduced. To increase the contact area between the ion-sensitive membrane and the AgX layer, A
It is already known to increase the surface area by reducing the particle size of gX, and Japanese Patent Publication No. 7-21482.
The publication discloses that the particle size is 1 μm or less. Further, for example, when an ion-sensitive film containing a polyvinyl chloride resin and its plasticizer is used, a soft ion that follows the fine irregularities of the AgX layer by increasing the plasticizer content in the ion-sensitive film To form a sensitive film and increase its contact area is disclosed in the prior application (Japanese Patent Application No. 9-3678).
No. 10 specification). However, reducing the particle size of AgX and increasing the contact area of the ion-sensitive membrane have limitations on the electrode having a limited area where the in-sensitive membrane is provided. In addition, there has been a demand for a method of incorporating a potential stabilizing substance into the above-mentioned ion-sensitive membrane and modifying the AgX layer itself to reduce its electric resistance.

A first object of the present invention is to provide an ion sensor having a silver / silver halide electrode which can reduce the electric resistance of a silver halide layer, an ion sensor plate, and a method of manufacturing the same. A second object of the present invention is to provide an ion sensor capable of reducing electric resistance at an interface between a silver halide layer of a silver / silver halide electrode and an ion-sensitive film,
An object of the present invention is to provide an ion sensor plate and a method for manufacturing the same. A third object of the present invention is to provide an ion sensor, an ion sensor plate, and a method of manufacturing the same, which have high measurement accuracy of a detected value of ion concentration. A fourth object of the present invention is to provide a method of manufacturing an ion sensor and an ion sensor plate that can easily and quickly increase the silver / halogen atomic ratio of a silver halide layer of a silver / silver halide electrode. A fifth object of the present invention is to reduce the variation in the resistance and the silver / halogen atomic ratio of the silver / silver halide electrode without leaving impurities in the silver halide layer. An object of the present invention is to provide a method for manufacturing an ion sensor and an ion sensor plate which can be enlarged.

[0006]

According to the present invention, in order to solve the above-mentioned problems, (1) the surface provided on a silver layer is formed by a halo.
At least one pair of a sample liquid measurement electrode and a reference electrode having a coating film of an ion-sensitive film sensitive to specific ions on a modified silver halide layer obtained by modifying a silver halide layer formed by genification An ion sensor provided with an ion sensor plate main body, and a measuring circuit connected to the ion sensor plate main body so that a specific ion concentration of a sample liquid can be measured, wherein the modified silver halide layer is the silver layer
Silver ions are reduced after providing the above silver halide layer on top
A layer treated with a reducing unit, provide an ion sensor reforming is to at least 1.2 atomic ratios Ag / X of silver and silver of the silver halide layer of the modified silver halide layer Is what you do. Also, the present invention
(2) the ion sensor of (1), wherein the grain size of silver halide and silver in the modified silver halide layer is at most 1 μm; (3) the surface thereof provided on the silver layer is halogenated;
An ion sensor comprising a pair of a sample liquid measurement electrode and a reference electrode having a coating film of an ion-sensitive film on a modified silver halide layer obtained by modifying a formed silver halide layer, and at least one set provided on a substrate. A plate body, a closed flow path for supplying a sample liquid to the sample liquid measurement electrode, and a closed flow path for supplying a reference liquid to the reference electrode are formed on the substrate surface, and communicate with the respective flow paths. A sample liquid inlet, an upper cell having a reference liquid inlet, and at least a liquid junction provided in the ion sensor plate body and supplied to the respective flow passages, a liquid junction for liquid junction of the reference liquid, The modified silver halide layer is the silver halide layer on the silver layer.
After being provided, is treated by a reducing means for reducing silver ions.
And a layer, the ion sensor plate reformer of the reforming silver halide layer is to at least 1.2 atomic ratios Ag / X of silver and silver of the silver halide layer,
(4) The ion sensor plate of ( 3 ), wherein the grain size of silver halide and silver in the modified silver halide layer is at most 1 μm. ( 5 ). method for producing an ion sensor processing or the by halogen ion solution is to etch the grain boundaries of the silver halide layer under natural light (1) or (2) by, (6), treatment with a reducing means mainly ultraviolet It is another object of the present invention to provide a method for producing an ion sensor plate according to the above (3) or (4) , wherein the grain boundary of the silver halide layer is etched with a halogen ion solution under treatment with light irradiation or natural light.

In the present invention, “reducing means” means silver halide AgX (X represents a halogen atom, and the same applies hereinafter).
It is a means to increase the proportion of silver in the layer. Means for reducing silver ions to silver are mentioned. Specifically, for example, in addition to physical reduction means of ultraviolet rays, light rays containing ultraviolet rays (light rays mainly containing ultraviolet rays, natural light, etc.), reducing agents using chemicals, etc. Means for chemical reduction. When ultraviolet rays or light rays containing ultraviolet rays are applied to the silver halide layer, the silver ions of the silver halide are reduced to silver and released, but those which become volatile gas and evaporate are removed. This is preferable in that it can be easily performed. Reducing the silver halide, it is possible to reduce the particle size of the silver halide of the reforming halo gain down and silver layer after reduction treatment by discharging halogen ions to the outside of the silver halide layer, of course In particular, the grain size of the silver produced by the reduction can be made smaller than that of the original silver halide, and the atomic ratio Ag / X between silver and halogen can be made larger. Reforming the silver halide and silver of the particle size of the halo gain emissions of silver layer after reduction 1μ
m (at most 1 μm).
The g / X ratio is at least 1.2 (at least 1.2).
Since the surface area is increased and the reduction reaction is performed over a wide range by reducing the grain size of the silver halide, the silver ion reduction efficiency is good and the Ag / X ratio is easily improved.
The silver halide in the Ag / X layer is modified by dissolving the grain boundaries, so-called etching is performed using a solution containing a halogen ion (a non-aqueous solution such as an alcohol such as an organic chloride capable of supplying a halogen ion described below). object solution performed etching mild and is easy to control the degree of etching conducted at even or) other chloride solutions, silver halide halide ions and AgX ₂ solution ^- to form a complex of silver halide Dissolves from the grain boundaries, the crystals are shaved and the particle size is reduced. It is observed that the underlying silver layer is exposed from between the melted grain boundaries, and this also increases the Ag / X ratio, but the “reducing means” includes this. As described above, by reducing the particle size of silver chloride in the modified silver halogenated layer, the contact area with the ion-sensitive film is increased, and by increasing the ratio of silver in the silver halide layer,
The electron conductivity of a silver halide layer containing silver halide, which is originally an insulator, is improved.

In the present invention, the electrical resistance of the silver halide layer is reduced and the dissociation equilibrium of AgX (AgX
= Ag ⁺ + X ^-) constituents is controlled to be dissolved in the ion-sensitive membrane to the dissociation equilibrium to stabilize (fixed), the potential stabilizing substances to ion-sensitive membrane, to contain the related substances In this case, the potential at the interface between the silver halide layer and the ion-sensitive film is rapidly stabilized, and the variation in the potential is small. The accuracy of the process is good, and the cost in the production process can be reduced. Potential stabilizing substances contained in these ion-sensitive membranes, and related substances, include Ag ⁺ and / or X ⁻ at the concentration of at least Ag ⁺ and X ⁻ at the time of dissociation equilibrium of AgX = Ag ⁺ + X ⁻ ) is contained, X in ion-sensitive membrane at ^- If is contained, if too especially contained more than the concentration at the time of dissociation equilibrium, the silver halide salts of AgX, especially the latter Ag
Becomes X ^1-n _n complex, because it is easy to dissolve in the ion sensitive membrane, previously dissolved AgX to its saturation concentration in the ion-sensitive membrane is not subject to anion interference from the analyte solution and the reference solution to the ion-selective membrane As described above, an anion eliminator (for example, N
a-TPB (sodium tetrakisphenylborate), K-TCPB (potassium tetrakis-p-
When used in combination chlorophenyl borate)) is, Ag ⁺ and X in the ion-sensitive membrane ^- or the AgX ^1-n _n complex is present at a high concentration, these ions or complex cause associated with anionic exclusion agent, Because it becomes an ion pair, the effective concentration of these ions and complexes decreases,
Ionophore, which is an ion-sensitive substance added to the ion-sensitive membrane, is added in advance. This is a different system from the above, but the anion scavenger described above is sufficient to eliminate anions from the sample solution and the reference solution. Above the concentration (at least that concentration), eg at least 1 in the case of Na-TPB
X 10 ^-2 M (mol) (1 x 10 ^-2 M or more) is added. Each of these means can be used in combination.

In this case, AgX = Ag
⁺ + X ^- is the dissociation equilibrium is immobilized, the AgX layer of the multi-ion sensor plate individual electrode manufactured Ag ^+, X
^The slight variation in the amount of-dissolved in the ion-sensitive membrane and the change in the amount of dissolved due to changes in the surrounding environmental conditions can be neglected, and the potential generated at the interface between the AgX layer and the ion-sensitive membrane is extremely low. Is controlled within a narrow range. In addition, AgX is previously mixed into the ion-sensitive membrane, so that AgX of the AgX layer becomes AgX ^1-n _n
Formation of a complex and dissolution in the ion-sensitive membrane can be avoided, and the dissociation equilibrium of AgX = Ag ⁺ + X ⁻ is fixed. Is gradually dissolved in the ion-sensitive membrane, AgX = A at the interface between the AgX layer and the ion-sensitive membrane.
Not only does the dissociation equilibrium of g ⁺ + X ⁻ not be fixed, but over a very long period, the underlying AgX is dissolved and the Ag layer is exposed, and from the difference in the equilibrium potential of AgX and Ag of the metal,
There is a risk that an error occurs in the generated potential, but in the former case, this can be avoided. In general, a silver halide salt of AgX is used in a solution containing a high concentration of X ^−.
It is known to dissolve as gX ^1-n _n complex. In addition, cations of the above-mentioned associated ion pairs are chelated with ionophores, and Ag ⁺ , X ⁻ , AgX
^1-n _n-called potential determining ion complex, to improve the effective concentration in the ion-sensitive membrane of the complex, AgX = Ag ⁺
+ X ^- can be immobilized to the dissociation equilibrium of. Also, in, for example, since the Na-TPB is known to Na, reacts with ⁺ alkali metal or monovalent metal ions M with the exception of Li results in a poorly soluble precipitate of M-TPB, Ag ⁺ Tomo It is considered that Ag-TPB reacts with Ag-TPB. However, if Na-TPB is contained in the ion-sensitive membrane in the above-mentioned predetermined amount or more, Ag ⁺ generated between lattices of AgX layer and Ag generated by dissolution are obtained.
⁺ Reacts at the interface between the AgX layer and the ion-sensitive membrane to form Ag.
-TPB is formed. As a result, Ag at the interface
X is replaced with Ag-TPB, and the generated potential is A
Although determined by the dissociation equilibrium of g-TPB = Ag ⁺ + TPB ⁻ , the concentration of TPB in the ion-sensitive membrane is controlled to a predetermined concentration or higher, that is, 1 × 10 ⁻² M or higher.
^The dissolution of ⁺ and TPB ^-into the ion-sensitive membrane is controlled,
^{Ag-TPB = Ag + + TPB} - the dissociation equilibrium is immobilized, evolution potential is stabilized. In this case, AgX = A
g + ⁺ X ^- in so cause shake equilibrium is lost, not the problem to be solved in the case of adopting a means of the above.

[0010] Cl ^- as a source of, but specifically include trioctylmethylammonium chloride for example, the general formula R ₄ N ⁺ Cl - ^(R represents an alkyl group,
The same effect can be obtained as long as it is an ammonium salt represented by the following. The same is true, and a phosphonium salt represented by, for example, a general formula R ₄ P ⁺ Cl ⁻ may be used instead of the ammonium salt. X has the same effect as Cl in Br and I in addition to Cl. In the general formula, R ₄ N ⁺ Br ⁻ , R _{4
^{N + I -, R 4 P}} + Br -, R 4 P + I - and the like can be given compounds. The invention relating to the above-mentioned potential stabilization is described in detail in the specification of Japanese Patent Application No. 9-367808, which can be used.

In the present invention, a polyvinyl chloride resin is used as a material for the ion-sensitive film, and the plasticizer may be contained in the ion-sensitive film in an amount of 40 to 80% by weight. In the case where the resin is contained by weight, the plasticizer in the resin solution for the ion-sensitive membrane is a so-called poor solvent that does not have high solubility in the polyvinyl chloride resin, and therefore, by increasing the use ratio of the resin to the resin, And the dispersion of the ionophore and other additives in the plasticizer can be improved, and the solution is added dropwise to form a coating film. Convection hardly occurs, does not cause `` citrus skin '', the added ionophore and the added salt, and the dispersed state of the added potential stabilizing substance are also well maintained, And its fluidity of the coating film have also been maintained, it is possible to film a more uniform composition. As described above, the dispersion state of the potential stabilizing substance, the ionophore, and the like is also good. When a film having a uniform composition is formed, the state of penetration of the moisture of the sample liquid and the reference liquid is made uniform, and the dispersion of measured values can be reduced. In addition, the ion-sensitive membrane in which the plasticizer is used in an increased amount with respect to the polyvinyl chloride resin has sufficient flexibility, adheres closely to the fine irregularities of the above-mentioned modified silver halide layer, and contacts the ion-sensitive membrane. The area can be increased, the resistance at the interface between the ion-sensitive film and the silver halide layer can be reduced, and the potential stabilizing substances and ionophores contained in the ion-sensitive film are the same as those of the silver halide described above. Control that stabilizes the chemical equilibrium works efficiently, which not only improves initial characteristics, but also quickly stabilizes the potential at the interface between the silver halide layer and the ion-sensitive film, and reduces variations in initial characteristics. In addition, variations in measured values can be reduced. If the initial characteristics are quickly stabilized, the inspection can be performed quickly, and if the variation is small, the yield rate can be improved. In this way, it is possible to provide an ion sensor and an ion sensor plate having not only high reliability but also high productivity. In particular, even if a plasticizer or the like is dissolved in a sample liquid or a reference liquid, the influence thereof is small. It is useful as a one-time use disposable simple ion sensor and ion sensor plate. Examples of the polyvinyl chloride resin include a vinyl chloride resin, a copolymer of vinyl chloride and at least one of vinyl acetate, vinyl alcohol, a carboxyl group-containing monomer, and other vinyl monomers. As the phthalic acid-based plasticizer, aliphatic dibasic acid-based plasticizer, ethers of substituted or unsubstituted phenols and higher alcohols and other plasticizers can be mentioned, and these are used in a ratio where the plasticizer increases. Or other cases. The invention relating to the content of the plasticizer is described in detail in Japanese Patent Application No. 9-368810, which can be used.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, a joined body of a multi-ion sensor plate main body 5 and a bank body 9 shown in FIG. 2 is prepared. FIG. 1 is a cross-sectional view around an electrode on the side for supplying a sample liquid. Is shown. In the figure, 1 is a glass epoxy substrate, 2a is a sample liquid measuring electrode, 4a is a modified silver halide layer, 3 is not shown in FIG. 2, but is formed in a through hole 6a of a silver halide layer such as a silver chloride layer. The multi-ion sensor is covered except for a part of the exposed portion and the outer end (external electrode) of the electrode, and the other electrodes not shown are also covered. An insulating film covering the surface of the plate body 5, 4c is a window, 9 is a bank, 6a is a through hole, and 2d is an ion sensitive film. Here, although not shown in detail, the modified silver halide layer 4a is formed by plating the copper foil of the sample liquid measuring electrode 2a with silver, and then, for example, by means of electrolytic anodic oxidation or the like. Forming a silver halide layer having a diameter, as a reducing means for increasing the ratio of silver to the silver halide layer, for example, ultraviolet light for reducing silver ions, a physical reducing means such as a light ray containing ultraviolet light, or a chloride solution Is formed by using the etching means according to (1). When ultraviolet rays or light rays containing ultraviolet rays are irradiated on the silver halide layer, silver of the silver halide is reduced and released,
As the halogen ion, a chlorine ion which is easily used as a volatile gas and is easily used and usually easy to handle is preferable. The silver ions become silver when reduced, and by excluding the halogen ions, and by dissolving the grain boundaries of the grains by etching, the grain size of the silver halide crystals in the silver halogenated layer is 1 μm or less ( At most 1 μm, the same applies hereinafter), preferably 0.8 μm
m, more preferably 0.7 μm or less, but the particle size of the silver produced by the reduction can be adjusted in this manner. In addition, the atomic ratio A of silver and halogen in the crystals of the silver chloride layer
g / X can be increased, and can be set to 1.2 or more (at least 1.2, the same applies to the following), preferably 1.3 or more, more preferably 1.6 or more. in this way,
As the grain size of the silver halide layer becomes smaller, its surface area increases, and the contact area with the ion-sensitive membrane increases.As the proportion of reduced silver increases, the electron conductivity improves, Resistance can be reduced.

[0013] Next, the multi-ion sensor shown in FIG.
Through holes 6a to 6e of the embankment of the joint body of the main body 5 and the embankment 9;
For example, polychlorinated is formed in the through holes 6a and 6'a of 6'a to 6'e.
Vinyl resin, plasticizer, ion sensitive material, if necessary
Addition of an anion eliminator such as Na-TPB, K-KTPB, etc.
Salting and, if necessary, dissociation equilibrium of the above silver halide etc.
Stabilize the electrode between the silver halide layer and the ion-sensitive membrane.
The above-mentioned silver halide that stabilizes the potential generated at the interface
Dissociation equilibrium constituents or substances that dissociate their ions
Stabilizing substance of anion exclusion agent added in excess or excess
Quality or their anion scavengers and other potential stable
Same as ion-sensitive membrane used in combination with at least one
Specified ions containing the same type of excess ionophore
A resin solution for an ion-sensitive membrane, wherein the solution is non-volatile
Plasticizer for the whole part (the whole ion-sensitive membrane after drying)
40-80% by weight, preferably 65-80% by weight, more
Preferably 65-78% by weight, more preferably 70-7%.
5% by weight of a resin solution is added dropwise, dried, and
To form an ion-sensitive electrode and an ion-sensitive electrode
You. Further, the other through holes 6b and 6'b, 6c and 6'c, 6d
And 6'd, 6e and 6'e have different ion sensitivity
The resin solution for film is dropped in the same manner as described above and dried.
The other specific ion-sensitive membranes
Form an on-sensitive electrode. Thus, the potential stabilizer
Quality and its related substances, as described above,
Stabilizes the potential at the interface between the on-sensitive film and the silver halide layer
Can be Also, if a large amount of plasticizer is contained,
Increased the amount of plasticizer used for polyvinyl chloride resin
Ion-sensitive membranes are sufficiently flexible and, as described above,
The surface area can be reduced by reducing the particle size of silver
Increased fine irregularities on the surface of the modified silver halide layer
Following, the contact area increases, and the electrical
Resistance can be reduced.

As a final step, the joined body of the multi-ion sensor plate main body 5 and the bank body 9 is replaced with a concave part 10 of a lower cell 10 made of a transparent acrylic resin plate as in the case of FIG.
a, 10b, and the upper cell 12 made of a transparent acrylic resin is bonded to the lower cell 10 with a double-sided adhesive tape, and the above-mentioned bonded body is mounted. The sample liquid inlet 15 and the reference liquid inlet 16 of the multi-sensor plate having such a structure.
Respectively, a sample solution and a reference solution are injected by a syringe or the like, and the respective solutions are passed through the flow passages 13 and 14, and the respective solutions are supplied to the ion-sensitive electrodes in the through holes 6a to 6e and 6'a to 6'e. And at the same time, they are brought into contact at the liquid junction 7 so that electrical conduction can be achieved. Then, by inserting the terminals of the measuring instrument (not shown) into the terminal insertion holes 18a and 18b and bringing them into contact with the external electrodes of the electrodes, five different ion concentrations in the sample liquid can be measured.

[0015]

Next, embodiments of the present invention will be described. Example 1 For convenience, the electrodes of the multi-ion sensor plate main body 5 shown in FIG. 2 will be described with respect to the electrodes on the side for supplying the sample liquid shown in FIG. The silver-plated electrode was used as an anode and the platinum-plated titanium mesh was used as a cathode in a hydrochloric acid solution at an anode current density of 0.23 A / dm ^{2 for} 2/4.
Anodize by electrolysis for 0 seconds to form a silver chloride layer composed of silver chloride particles having a particle size of about 1 μm (measured by a scanning electron microscope, the same applies hereinafter). UV (intensity 70 mW / cm ² )
Irradiate for 0 second to form the modified silver chloride layer 4a. FIG. 3 shows a scanning electron micrograph after the irradiation with the ultraviolet rays.
The particle size of the modified silver chloride layer after this UV irradiation is 0.2 μm or more.
It was 0.7 μm. Further, the atomic ratio Ag / Cl of silver and chlorine of the modified silver chloride layer after the irradiation of the ultraviolet rays was changed to EDS.
(Energy dispersive element detector), the result was as shown in FIG. FIG. 7 shows the results of measuring the resistance value of the modified silver chloride layer after the irradiation of the ultraviolet rays.
Note that the dotted line is an improvement reference line. The electrode on the side supplying the sample liquid is formed in this manner. The electrode on the side supplying the reference liquid, which is a pair with the electrode, is formed in the same manner, and the other pairs of electrodes are formed in the same manner. Then, as shown in FIG. 2, a joined body in which the multi-ion sensor plate main body 5 and the bank body 9 are joined is prepared. Next, in order to form an ion-sensitive membrane to the electrodes, DOA plasticizers (dioctyl adipate) 2 g to trioctylmethylammonium chloride quaternary amine salts, such as chloride ^- chlorine (Cl sources) 0.8 mg Then, 10 mg of powdered AgCl (potential stabilizing substance) is further added, followed by stirring. A supernatant (250 mg) of the mixed solution was separated, and 72 mg of PVC (copolymer of vinyl chloride: vinyl alcohol: vinyl acetate = 90: 6: 4, manufactured by Denki Kagaku Kogyo KK) and valinomycin (ionophore for potassium ion detection) were collected. ) 14 mg, K-
TCPB (potassium tetrakis (p-chlorophenyl) borate, manufactured by Dojin Chemical Co., Ltd., anion exclusion agent)
24 mg was added, and 250 mg of THF (tetrahydrofuran) as a solvent was further added to obtain a resin solution for an ion-sensitive membrane. The proportion of DOA in the non-volatile components other than THF of the resin solution for an ion-sensitive membrane can be approximated to 75% by weight.
As described with reference to FIGS. 1 and 2 above, this resin solution for an ion-sensitive film is used to form the silver chloride layer 4 through the through holes 6a and 6'a.
a and 4b were applied by dripping and dried naturally to form a potassium ion-sensitive film as an ion-sensitive film 2d. Twenty multi-ion sensor plates having the structure shown in FIGS. 1 and 2 were prepared, and an aqueous solution containing 4 mM KCl was used as a sample solution, and a predetermined reference solution was used as a reference solution, using each of them at the beginning of manufacture. FIG. 8 shows the result of measuring the potential by the above-described measuring method in the case where the voltage was applied and obtaining the standard deviation σ (mV). Note that the dotted line is an improvement reference line. The actual measured value of the potassium ion concentration is obtained by applying the measured value of the potential to the relationship between the potential and the concentration determined in advance. The same applies hereinafter.

Example 2 In Example 1, the irradiation condition of the ultraviolet rays was 70 mW / cm.
FIG. 6 shows the result of calculating the Ag / Cl ratio of the modified silver chloride layer in the same manner except that the time was set to ² and 30 seconds, and FIG. 7 shows the result of measuring the resistance value. Except that the silver chloride layer was formed in this manner, 20 multi-ion sensor plates each having a potassium ion-sensitive film were prepared in the same manner as in Example 1, and the potential of these was also measured in the same manner as in Example 1. Is measured, and the standard deviation thereof is shown in FIG.

Example 3 In Example 1, after the silver chloride layer was formed, the silver chloride layer was immersed in a solution containing 10 mM (mmol) of chloride ions (ethanol solution of trioctylmethylammonium chloride) for 5 hours. Etching was performed to slightly dissolve the silver chloride grain boundaries. This operation was performed under natural light to form a modified silver chloride layer, and a scanning electron micrograph of the particle size is shown in FIG. The particle size of the particles of the modified silver chloride layer after this etching treatment was 0.4 μm to 0.8 μm. FIG. 6 shows the result of analyzing the silver / chlorine atomic ratio Ag / Cl ratio of the modified silver chloride layer in the same manner as in Example 1, and the result of measuring the resistance value of the modified silver chloride layer. As shown in FIG. Except for forming the modified silver chloride layer in this manner, 20 multi-ion sensor plates each having a potassium ion-sensitive membrane were prepared in the same manner as in Example 1,
For these, the potential was measured in the same manner as in Example 1, and
FIG. 8 shows the result of calculating the standard deviation.

Comparative Example 1 An electrode was formed in the same manner as in Example 1 except that the irradiation was not performed with ultraviolet rays and the subsequent operation was performed under natural light. FIG. 5 shows a scanning electron micrograph of the particle size of the particles in the silver chloride layer. The particle size was about 1 μm. FIG. 6 shows the result of determining the Ag / Cl ratio of the silver chloride layer, and FIG. 7 shows the result of measuring the resistance value. Except that the electrodes were formed in this manner, 20 multi-ion sensor plates each having a potassium ion-sensitive membrane were prepared in the same manner as in Example 1, and the potentials were measured for these in the same manner as in Example 1. FIG. 8 shows the result of calculating the standard deviation.

From the above results, Example 1 is the best in various measured values, followed by Example 2 and then Example 3. However, Example 3 is also superior to the comparative example. The better the effect of ultraviolet irradiation, the better the result.

In the above invention, the grain size of the grains of the modified silver halide layer is from 0.2 μm to 0.7 or from 0.2 μm to 0.2 μm.
0.8 μm, 0.4 μm to 0.7 μm or 0.4 μm
It may be 0.8 μm, and the Ag / X ratio is 1.2 to 1.6.
Alternatively, it may be 1.3 to 1.6, 1.6 or more (in the presence of a silver halide layer).

[0021]

According to the present invention, the surface provided on the silver layer is provided.
A of the modified silver halide layer formed by halogenating the surface
Since the g / X ratio is at least 1.2, the electric resistance of the modified silver halide layer can be reduced, and the particle size of the particles of the modified silver halide layer is 1 μm or less, so that the ion-sensitive film contact area between the can be increased, these makes it possible to reduce the electric resistance at the interface between the silver halide layer and the ion-sensitive membrane, the potential at the interface of ions thereby generated by the current flowing through the measuring circuit , The noise due to the variation in the potential at the interface can be reduced, and an ion sensor and an ion sensor plate with high measurement accuracy of the ion concentration detection value can be provided. Also, if a light mainly containing ultraviolet rays or an etching means under natural light is used as the reducing means to increase the Ag / X ratio, the reduction can be performed easily and quickly. since it is not necessary to use, without leaving impurities to form a low resistance and little modification silver halide <br/> layer of the variation.

[Brief description of the drawings]

FIG. 1 is a partial sectional view of a multi-ion sensor plate according to one embodiment of the present invention.

FIG. 2 is an exploded perspective view of a multi-ion sensor plate.

FIG. 3 is an electron micrograph of a modified silver chloride layer of an electrode of the multi-ion sensor plate according to one embodiment of the present invention.

FIG. 4 is an electron micrograph of a modified silver chloride layer of an electrode of a multi-ion sensor plate according to another embodiment of the present invention.

FIG. 5 is an electron micrograph of a modified silver chloride layer of an electrode of a multi-ion sensor plate of a comparative example.

FIG. 6 is a table showing the results of measuring the Ag / Cl ratio of the silver chloride layers of the electrodes of the multi-ion sensor plates of Examples and Comparative Examples of the present invention.

FIG. 7 is a graph showing resistance values of a modified silver chloride layer and a silver chloride layer using the multi-ion sensor plates of Examples and Comparative Examples of the present invention.

FIG. 8 is a graph showing the standard deviation of the measured values of the potentials of the electrodes using the multi-ion sensor plates of Examples and Comparative Examples of the present invention.

[Explanation of symbols]

 2a Sample liquid measurement electrode 2b Reference electrode 2d Ion-sensitive membrane 5 Multi-ion sensor plate main body 7 Liquid junction 13, 14 Flow passage

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Akihiko Mochizuki 6-16-20 Ueno, Taito-ku, Tokyo Taiyo Yuden Co., Ltd. (56) References JP-A-6-288962 (JP, A) JP-A-3 -87644 (JP, A) JP-A-54-133400 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 27/28 331 G01N 27/30 311 G01N 27/333

Claims (6)

(57) [Claims] Claims: 1. A surface provided on a silver layer is halogenated.
Ion having at least one pair of a sample liquid measurement electrode and a reference electrode having a coating film of an ion-sensitive film sensitive to a specific ion on a modified silver halide layer obtained by modifying a formed silver halide layer An ion sensor provided with a sensor plate main body, and a measurement circuit connected to the ion sensor plate main body so that a specific ion concentration of a sample liquid can be measured, wherein the modified silver halide layer is provided on the silver layer.
Reduction means for reducing silver ions after providing a silver halide layer
By a layer that has been treated, modification of the modified silver halide layer is silver and the halogen of said silver halide layer atomic ratio Ag /
An ion sensor wherein X is at least 1.2. 2. The ion sensor according to claim 1, wherein the grain size of silver halide and silver in the modified silver halide layer is at most 1 μm. 3. The surface provided on the silver layer is halogenated.
Ion having at least one pair of a sample liquid measurement electrode and a reference electrode provided on a substrate and having a coating film of an ion-sensitive film formed on a modified silver halide layer obtained by modifying the formed silver halide layer. A sensor plate body, a closed flow path for supplying a sample liquid to the sample liquid measurement electrode, and a closed flow path for supplying a reference liquid to the reference electrode are formed on the substrate surface, and communicate with the respective flow paths. A sample liquid supply section, an upper cell having a reference liquid supply section, and at least a liquid junction provided in the ion sensor plate main body and supplied to the respective flow passages, and a liquid junction section for liquid junction of the reference liquid. The modified silver halide layer is provided on the silver layer and the silver halide layer
After being provided, is treated by a reducing means for reducing silver ions.
And a layer, the ion sensor plate reformer of the reforming silver halide layer is to at least 1.2 atomic ratios Ag / X of silver and silver of the silver halide layer. 4. The ion sensor plate according to claim 3, wherein the grain size of silver halide and silver in the modified silver halide layer is at most 1 μm. Wherein the treatment with a reducing means of the ion sensor according to claim 1 or 2 grain boundaries is to etch the silver halide layer by a halogen ion solution under processing or natural light by mainly comprising light irradiating ultraviolet rays Production method. 6. The ion sensor plate according to claim 3, wherein the treatment by the reducing means is treatment by irradiation with light mainly containing ultraviolet rays or etching of the grain boundaries of the silver halide layer with a halogen ion solution under natural light. Manufacturing method.