JPH04215057A - Planar type ion electrode - Google Patents

Abstract

PURPOSE:To provide a planar type ion electrode which is simple in structure, easy to manufacture, rapid in a response speed during measurement, high in measurement precision, and reduced in size and cost. CONSTITUTION:A planar type ion electrode comprises a hole resistant electrode support base 1, a working electrode 2 formed so that a filmy titanium nitride electrode formed on an electrode support base 1 is covered with an ion selective high molecular film, a comparing electrode 3 formed to make the electrode support base 1 impregnated with internal liquid and silver is formed in a filmy state on the support base in a state to make contact with the internal liquid, and an insulating protection film with which a whole except a sensing part 2a of the working electrode 2, a liquid junction 3a of the comparing electrode 3, and a connection part between the working electrode 2 and the comparing electrode 3 is covered.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode for ion measurement, and more particularly to a planar ion electrode that has a simple structure, is easy to manufacture, and is inexpensive and easy to handle.

0002

2. Description of the Related Art Ion electrodes for measuring ions in a solution are classified into liquid film type electrodes, fixed membrane type electrodes, gas sensitive type electrodes, and the like. Each of these ion electrodes is used in pairs with a reference electrode, which is a glass tube with a liquid junction filled with a saturated potassium chloride solution.
Those immersed in silver chloride electrodes are generally used. In addition, these ion electrodes, except for some fixed membrane electrodes,
It has an internal fluid.

0003

[Problems to be Solved by the Invention] Many conventional ion electrodes contain an internal liquid, and the reference electrode requires a liquid junction with the test liquid, so the problems listed below arise. There is a point.

[0004] The reference electrode has a complicated structure such as a space for storing the internal liquid, an injection port for the internal liquid, and a liquid junction, making it impossible to mass produce, expensive, and difficult to miniaturize. Since the electrode has a built-in internal liquid, the shape of the electrode and the conditions in which it can be used are limited. In addition, they are generally easily damaged and damaged, so careful handling and careful maintenance are required. Furthermore, glass electrodes have a high electrical resistance (100 to 1000 megohms at room temperature), and ion measurement requires a DC amplifier with high input resistance, requiring special consideration and ingenuity in the measurement circuit. Moreover, various substances in the test liquid adhere to the sensitive membrane or gas permeable membrane (porous membrane in the case of a liquid film type electrode) during measurement, resulting in deterioration of measurement accuracy.

[0005] The present invention was made in view of these problems, and aims to provide a small and inexpensive planar ion electrode that is easy to manufacture, has a fast response speed during measurement, and has high measurement accuracy. purpose.

[0006]

[Means and operations for solving the problem] In order to achieve this object, the planar ion electrode of the present invention has the following features:
The structure is as follows.

A planar ion electrode consists of an electrode support substrate, a working electrode formed by covering a thin metal film formed on the electrode support substrate with an ion-selective polymer membrane, and an internal liquid that is connected to the electrode support substrate. and a thin film-like reference electrode formed on a supporting substrate so as to be in contact with this internal liquid, excluding the sensitive part of the working electrode, the liquid junction part of the reference electrode, and the connection part of the working electrode and the reference electrode. It is characterized by comprising an insulating protective film covering the entire surface.

In a planar ion electrode having such a configuration, the working electrode is formed by forming a metal having hydrogen ion selectivity (pH characteristics), such as titanium nitride, into a band-shaped thin film on an insulating support substrate. An ion-selective polymer thin film is coated onto this. The comparison electrode is constructed by forming a metal such as silver/silver chloride into a strip-shaped thin film on a foamable support substrate, and impregnating this support substrate with an internal liquid.

The planar ion electrode with this structure has an extremely simple structure and manufacture, and can be made smaller, lower in price, and mass-produced.There is almost no variation between electrodes in terms of characteristics and shape, and the The price makes it disposable. Furthermore, the structure is simple, the supporting substrate is robust and will not be damaged or damaged, and is easy to handle. Furthermore, since the film-like electrodes are formed on the support substrate, these electrodes can be used by directly inserting them into the connector. Moreover, it not only has a fast response speed during measurement, but also can be manufactured into any shape, giving a great degree of freedom in terms of usage.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a perspective view showing a specific embodiment of a planar ion electrode according to the present invention.

The planar ion electrode is a planar potassium ion electrode in the embodiment, and includes an insulating electrode support substrate 1, a thin film-like working electrode 2 formed on the electrode support substrate 1, and a thin film-like working electrode 2 formed on the electrode support substrate 1. and a comparison electrode 3.

As shown in FIGS. 2 and 4, the working electrode 2 includes an electrode support substrate 21, an electrode metal 22 formed in the form of a film on the electrode support substrate 21, and an electrode metal 22 formed on the electrode metal 22. The ion-selective polymer membrane 23 is a thin film. For the electrode support substrate 21, an alumina ceramic thin plate or a heat-resistant polyimide film is used. Further, the electrode metal 22 formed on the electrode support substrate 21 is made of titanium nitride (TiN) in the form of a film. The electrode supporting substrate 21 is covered with an insulating protective film (photosensitive polyimide film) 4 except for the sensitive part 2a and the connecting part 2b. Further, an ion-selective polymer thin film 23 is formed on the sensitive part 2a. Ion selective polymer thin film 2
No. 3 contains bis[(benzo-15-crown-5)-4'-methyl]pimelate as a potassium ion-selective substance in a polyvinyl chloride (PVC) thin film.

Although the detailed manufacturing process of this working electrode 2 will be omitted, mass production is possible. First, the titanium nitride 22 is formed by using a metal mask on an electrode support substrate (not shown) of 50 mm x 50 mm, and by an appropriate means such as ion plating, ion sputtering, or CVD. A band-like film (about 1 μm thick) is formed all at once, and an insulating protective film 4 is coated thereon by photolithography. That is, photosensitive polyimide is spin-coated on the electrode support substrate on which the titanium nitride 22 is formed, exposed to light while covering a glass mask, developed, and rinsed to cover the electrodes except for the sensitive parts 2a and the connecting parts 2b. . Furthermore, it is cut into the size of one working electrode 2 by suitable means. Next, an ion-selective polymer thin film 23 is formed on the sensitive part 2a. That is, bis[(benzo-15-crown-5)-4'
- 10 mg of methyl] bimelate and 20 mg of polyvinyl chloride
An appropriate amount of a solution prepared by dissolving 0 mg of the ester and adding 250 μl of o(ortho)-nitrophenyl octyl ether is dropped onto the sensitive area 2a and dried at 60° C. for 60 minutes.

The comparative electrode 3 is characterized in that the electrode supporting substrate 1 is impregnated with an internal liquid. Figures 3 and 5
As shown, the electrode support substrate 1 is made of a material with excellent insulation, heat resistance, and mechanical strength. In the example, porous ceramics (material is alumina mullite, composition is Al)
2 03 76%, SiO2 23%, porosity 43%)
is adopted. On the electrode support substrate 1, silver (Ag) 31 is formed as a film (film thickness of about 1 μm) as an electrode metal. Furthermore, an insulating protective film 5 is provided on the front and back surfaces of the electrode support substrate 1.
is coated except for the liquid junction part 3a and the connecting part 3b, and the electrode supporting substrate 1 is filled with an internal liquid.

The outline of the method for manufacturing the comparative electrode 3 is as follows. Formation of silver 31, which is an electrode metal, is carried out by, for example, 5
Parallel strips are formed by sputtering on the above-mentioned porous ceramic having a size of 0 mm x 50 mm. Film thickness is approximately 1μ
It is m. Next, by the photolithography method described above, the connecting part 3b, the mounting part 11 of the working electrode 2, and the liquid junction part 3a are
An insulating protective film 5 is coated on the front and back surfaces of the electrode support substrate 1 except for the electrode supporting substrate 1 . The working electrode 2 is attached to the attachment part 11 using an appropriate means such as adhesive. Furthermore, it is cut into the size of one planar type ion electrode by dicing or the like, and the exposed end surfaces 12, 13, and 14 of the electrode support substrate 1 are insulated and molded with epoxy resin 6.

A silver/silver chloride (Ag/AgCl) electrode is formed and an internal liquid is filled in the planar ion electrode thus manufactured. First, the planar ion electrode is 1.
It is immersed in a 0 N (normal) hydrochloric acid (HCl) solution and degassed under negative pressure to flow and fill the electrode support substrate 1 with hydrochloric acid. Next, the platinum (Pt) wire is immersed in the hydrochloric acid, and the comparison electrode 3 is connected between the platinum wire and the comparison electrode 3 at +0.5 V (volts).
A voltage is applied so as to form silver/silver chloride on the surface of the silver 31 on the electrode support substrate 1 side. Furthermore, this hydrochloric acid solution was completely removed and 4.0 M (mol) potassium chloride (KC
l) Fill the electrode support substrate 1 with the solution in the same manner.

Furthermore, the type and shape of the electrode metal, the working electrode 2
mounting method, type of ion-selective substance, membrane material, silver/silver chloride formation method, internal liquid filling method, epoxy resin 6 as an insulating mold material, etc. are not limited to these and may be changed as appropriate. It is possible.

As shown in FIG. 1, the planar ion electrode manufactured as described above is directly connected to the connecting portions 2b and 3b.
Insert and connect to connector 7 to use. FIG. 6 is an explanatory diagram for evaluating the characteristics of the example planar potassium ion electrode. In the figure, b shows the electrode output characteristics of a conventional commercially available potassium ion electrode, and a shows the characteristics of the planar potassium ion electrode of the example. This result proves that the planar potassium ion electrode of the example can be used as a potassium ion electrode.

FIG. 7 is an exploded perspective view of an example in which the planar potassium ion electrode A of the embodiment is applied to a mini flow cell 8. As shown in FIG. Reference numeral 91 denotes an acrylic plate (supporting member), which is shown upside down in FIG. On the back surface 91a of the acrylic plate 91, a silicone sheet (for example, 0.13 mm thick
The planar potassium ion electrode A of the above embodiment is embedded with SILASTIC sheeting (manufactured by Dow Corning) 92 arranged around the electrode. On the other hand, the mini-flow cell 8 is provided with a sample channel 81, and tube lines 82 and 82a are connected to both ends of the sample channel 81, respectively. This sample channel 8 is located on the top surface 8a of the mini flow cell 8.
1 is exposed, and a contact fitting 84 to which a lead wire 83 is connected is provided. Also, 85 is a pair of close fittings,
The groove portion 86 has a leaf spring 87. That is,
The acrylic plate 91 and the mini-flow cell 8 are attached by a contact tool 85 and brought into close contact by a leaf spring 87. At this time, the planar potassium ion electrode A is in close contact with the top surface 8a of the mini flow cell, and the exposed part of the sample flow path 84 is in contact with the sensitive part 2a of the working electrode 2, the liquid junction part 3a of the reference electrode 3, and the contact metal fitting. 84 are in close contact with the connecting portions 2b and 3b, respectively.

Although FIG. 7 shows an example in which a planar potassium ion electrode is applied to a mini flow cell, the application example is not limited to this and can be modified as appropriate.

[0021]

[Effects of the Invention] As described above, in the present invention, a working electrode is formed by coating an ion-selective polymer membrane on a thin metal film formed on an electrode support substrate, and the electrode support substrate is impregnated with the working electrode. A thin film-like comparison electrode is formed on the supporting substrate so as to be in contact with the internal liquid, and the entire area is covered with an insulating protective film except for the sensitive part of the working electrode, the liquid junction part of the reference electrode, and the connecting part of the working electrode and the reference electrode. Since the structure and manufacturing are extremely simple, miniaturization, low cost, and mass production can be realized, there is almost no variation between electrodes in terms of characteristics and shape, and the low price makes it disposable. becomes possible. Furthermore, the structure is simple, the supporting substrate is robust and will not be damaged or damaged, and is easy to handle. Furthermore, since the film-like electrodes are formed on the support substrate, these electrodes can be used by directly inserting them into the connector. Moreover, it not only has a fast response speed during measurement, but also can be manufactured into any shape and has a high degree of freedom in usage, and has excellent effects that achieve the purpose of the invention.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example planar ion electrode.

FIG. 2 is a cross-sectional view of an exposed sensitive part.

FIG. 3 is a cross-sectional view of a coated electrode part.

FIG. 4 is a longitudinal cross-sectional view of a working electrode.

FIG. 5 is a longitudinal cross-sectional view of a comparison electrode.

FIG. 6 is an explanatory diagram for evaluating the characteristics of the planar potassium ion electrode of the example.

FIG. 7 is an explanatory diagram in which a planar potassium ion electrode is applied to a mini flow cell.

[Explanation of symbols]

1 Insulating electrode support substrate 2 Working electrode 3. Reference electrode 23 Ion selective polymer membrane 2a Sensing part 3a Liquid junction

Claims (1)

[Claims] 1. An electrode supporting substrate, a working electrode formed by coating an ion-selective polymer membrane on a thin metal film formed on the electrode supporting substrate, and impregnating the electrode supporting substrate with an internal liquid; , a thin film-like comparison electrode formed on the support substrate so as to be in contact with this internal liquid, and covering the whole except for the sensitive part of the working electrode, the liquid junction part of the comparison electrode, and the connection part of the working electrode and the comparison electrode. A planar ion electrode consisting of an insulating protective film.