JP2552208B2 - Method of manufacturing chemical sensor and sensor plate - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical sensor for measuring the ion concentration of a sample liquid such as blood and a method for manufacturing a sensor plate of its component.

[0002]

2. Description of the Related Art In order to measure the ion concentration of a sample liquid such as blood, a sample liquid measuring electrode having an ion-sensitive film formed on a substrate and a reference electrode are provided in pairs, and a window portion is provided on the tip side of these electrodes. Is covered with an insulating film so as to form a reference liquid and a sample liquid in these windows, and in an ion conductive state,
There is known a so-called differential ion sensor in which each electrode is connected to a measurement circuit to measure a potential difference based on a concentration difference between a reference liquid and a sample liquid.

In order to manufacture this ion sensor, as proposed in the previous application, for example, a so-called printed wiring board in which a copper foil having a thickness of 35 μm is adhered on a paper polyester insulating substrate is subjected to copper by a photolithographic method or the like. The strips of the strips are separated from each other and arranged in a butt-shaped bear to be etched to form a conductive pattern of a predetermined shape, and the surface of the copper strip of the pattern is mirror-polished as necessary. Then, electrolytic plating is performed using a commercially available bright silver plating bath to form a silver layer of about 10 to 15 μm. Further, it is dipped in a hydrochloric acid solution and subjected to electrolytic chemical treatment to form a silver chloride layer of several μm on the surface of the silver layer.

Next, the surfaces of the pair of silver chloride layers are covered with an insulating film made of a resin such as an epoxy resin, leaving a part of the opposite ends thereof, to form a window. The pair of windows and the space between them are left, and the elongated holes corresponding thereto are formed to further form a bank on the insulating film. Then, an ion-sensitive material solution containing a macrocyclic compound called an ionophore, an ion-exchange resin or the like is dropped into the elongated hole including the window and dried to form an ion-sensitive film on the silver chloride layer of the window. As described above, the method of forming the ion-sensitive film only on the necessary portion of the silver chloride layer is more expensive than the ion-sensitive film formed on the entire surface after forming the above-mentioned silver chloride layer by using an ionophore or the like. There is an advantage that waste is reduced by not using many such materials.

[0005]

However, when the ion-sensitive material solution is dropped and the coating film is formed on the silver chloride layer of the window, the coating film is left to dry at room temperature in the atmosphere. And the solvent volatilizes. Therefore, the volatilization rate of the solvent is too fast, or the volatilization rate of the solvent is not constant in the ambient conditions such as the ambient temperature, resulting in variations in the film thickness of the dry coating film. The output potential of the sensor varies, and if a non-standard product is regarded as a defective product, the yield is reduced.

An object of the present invention is to reduce the variation of the film shape when forming the chemically sensitive film by dropping the chemically sensitive film material solution only on a necessary portion, and to provide a chemical sensor and a sensor plate having less variation of the output. To provide.

[0007]

In order to solve the above-mentioned problems, the present invention provides at least one pair of a sample liquid measuring electrode coated with a chemosensitive film and a reference electrode to provide a specific sample liquid sample. In the method of manufacturing a chemical sensor capable of measuring the concentration, the chemically sensitive film is formed by dropping a solution of the chemically sensitive film material, and the coating film is placed in a solvent atmosphere in which the chemically sensitive film is dissolved or swollen. you left
There is provided a method of manufacturing a chemical sensor.

Further, in a method of manufacturing a sensor plate in which at least one pair of a sample liquid measuring electrode coated with a chemically sensitive film and a reference electrode is provided on a substrate, the chemically sensitive film is made of this chemically sensitive film material. formed by dropping a solution, and is to provide a method of manufacturing a ruse down Sir plates to leave the coating film in a solvent atmosphere for dissolving or swelling the chemical sensitive membrane.

[0009] In this case, it is preferred that the solvent for dissolving or swelling is the same solvent as the chemical sensitive membrane material solution.

[0010]

[Function] When a chemically sensitive film material solution is dropped and left to stand in the atmosphere at room temperature to naturally dry the chemically sensitive film in its dissolving or swelling solvent atmosphere, the film dissolves or swells, so that the film easily flows. The volatilization of the solvent can be controlled slowly so that the surface can be leveled . Uniformity of the film shape is made in this way.

[0011]

Embodiments of the present invention will now be described with reference to the drawings. First, as shown in FIGS. 1 and 2, a copper foil adhered on a paper polyester substrate 1 is patterned by a photolithographic method, polished to a mirror surface with a diamond slurry of 2 μm, and elongated surfaces are separated from each other and arranged in a butted state. Then, the copper electrodes 1a and 1b having a predetermined shape were formed.

Next, degreasing with a commercially available degreasing agent and cathodic electrolytic degreasing were performed, followed by washing with water. After that, it was immersed in a commercially available bright silver plating solution (JPC Temper resist AGR (2) manufactured by Japan Kojundo Chemical Co., Ltd.) while maintaining the temperature at 30 ° C., and a platinum current titanium mesh was used as an anode, and a cathode current density was 10 A. / Dm ² (ampere per unit decimeter) electrolytically plated for 2 minutes and 30 seconds to a thickness of 10 to 15
The μm silver layers 2a and 2b were formed.

After that, the contact portion connected to the output circuit device is masked so as not to be silver chloride, and then 0.1
In normal hydrochloric acid, the electrode with the silver layer formed is the working electrode, the platinum electrode is the counter electrode, the silver / silver chloride electrode is the reference electrode, and the potentiostat and function generator are used.
After holding the initial potential at 80 mV for 60 seconds, the initial sweep direction was set to the cathode direction, sweeping up to -1500 mV, and folding back to 80 mV at a sweep rate of 50 mV / sec,
Then, from 350mV - sweep between 150mV speed 2
Sweep at 0 mV / sec for 5 cycles to preliminarily form a fine silver chloride layer. Then, the electrode on which this preliminary silver chloride layer was formed in 0.1N hydrochloric acid was used as the anode, and the platinum-plated titanium mesh was used as the cathode, and the anode current density was 0.23 A / d.
Electrolytic conversion treatment was carried out for 2 minutes and 40 seconds with m ² (ampere per unit decimeter) to form silver chloride layers 3a and 3b on opposite ends of the silver layers 2a and 2b. In this way, the standard electrodes consisting of 1a, 2a, 3a and 1b, 2
b, 3b, a sample liquid measuring electrode is formed.

The insulating film 4 is formed by an epoxy resin, leaving a part of the silver chloride layers 3a, 3b near the opposite ends and the exposed silver layers 2a, 2b as a contact portion of the probe. Then, recesses are formed in the insulating film 4, and the bank 7 having the elongated holes 6 corresponding to the former is formed in the insulating film 4, leaving the recesses and the spaces between them, and both end portions of the electrode and the insulating film 4.

In the elongated holes 6, sodium ionophore Bis (12-CROWN-4) and membrane solvent ortho-nitrophenyl octyl ether (o-NPO) are used.
E), a tetrahydrofuran (THF) solution containing a vinyl chloride copolymer as a carrier was dropped, and the solvent was volatilized in the air at room temperature to form a sodium ion sensitive film 8. In this way, the sodium sensor plate component is completed.

Next, a fixed amount of THF is placed in a closed container with a cock, and the inside of the container is kept in a THF saturated atmosphere. The sodium sensor plate component having the ion-sensitive film 8 formed therein is housed therein, and after the sodium-ion-sensitive film is sufficiently dissolved, the cock of the container is opened and the TH is gradually increased.
F was volatilized and the ion sensitive membrane was slowly regenerated over 2 hours.

A photograph of the surface of the sodium ion sensitive film thus obtained is shown in FIG. From this photograph, it can be seen that there is no local unevenness on the surface of the sodium ion sensitive film. Although not shown in the figure, it was confirmed that the film shape was uniform in the elongated hole 6, and that the film shapes were almost the same for other sodium sensor plates of the same lot manufactured by the same method. If the film shape is uniform, the film thickness also becomes uniform in each thickness, and variations are reduced.

A sheet body is further attached on the bank 7 of the sodium sensor plate component to provide an upper bank 9, and windows 9a and 9b corresponding to the recesses and a liquid communication hole 9c are formed. did. This completed the differential sodium ion sensor plate.

In this differential sodium ion sensor plate, the standard solution and the sample solution are dropped on the windows 9a and 9b, respectively, and the electrodes of the exposed silver layer are connected to an output circuit device (not shown). An output value can be obtained according to the difference in the contained ion concentration. A reagent solution having the same concentration (sodium ion concentration [Na ⁺ ] = 140 mM) was dropped onto the windows 9a and 9b of the differential sodium ion sensor plate, and variations in output value (ΔE, ideally ΔE = When 0) was measured, the probability that ΔE <0.5 mV was 90% or more.

Comparative Example 1 A sodium ion sensor plate component was prepared in the same manner as in Example 1 except that the ion-sensitive membrane was not regenerated with THF, and the same was used to prepare a differential sodium ion sensor plate. Was produced. The photograph of the surface of the sodium ion sensor plate parts of the ion-selective membrane shown in FIG. From this photograph, it can be seen that the ion-sensitive film has local unevenness. Moreover, irregularities were also observed in the portions of the elongated holes 6 not shown, and the shape of the ion-sensitive film formed in the elongated holes 6 was not uniform. Also,
The film shapes were different for other sodium ion sensor plates of the same lot manufactured by the same method.
No shape identity was observed. When ΔE was measured for the differential sodium ion sensor plate in the same manner as in Example 1, the probability that ΔE <0.5 mV was 50% or more.

[0021]

Although the same solvent as the material solution for the ion-sensitive film is used in the above, a solvent capable of dissolving the ion-sensitive film or a solvent capable of swelling may be used, and a plurality of solvents may be mixed and used.

Although the above description has been given with respect to the sodium ion sensitive film as an example, the same can be said for chemically sensitive films such as ion sensitive films of other types such as potassium, calcium, magnesium and hydrogen ion sensitive films.

[0024]

According to the present invention, the chemical sensitive film than that dissolved or swollen to to be played is <br/> leave chemical sensitive film in a solvent atmosphere, film within a single chemical sensitive film The shape can be made uniform, and the film shape can be made almost uniform between other chemically sensitive films formed using the same method. The output value of the chemical sensor using this chemically sensitive film Variation can be reduced. As a result, the yield of products can be improved.

[Brief description of drawings]

FIG. 1 is a top view of a differential sodium ion sensor plate according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line II-II of the differential sodium ion sensor plate of the above embodiment.

FIG. 3 is a photograph of the surface of a regenerated ion-sensitive membrane of the differential sodium ion sensor plate of the above example.

FIG. 4 is a photograph of the surface of a regenerated ion-sensitive membrane of a differential sodium ion sensor plate of a comparative example.

[Explanation of symbols]

 1 substrate (1a, 2a, 3a) standard electrode (1b, 2b, 3b) sample liquid measuring electrode 8 sodium ion sensitive membrane

Claims (4)

(57) [Claims] 1. A method for producing a chemical sensor, comprising a pair of at least one pair of a sample liquid measuring electrode coated with a chemically sensitive film and a reference electrode, wherein the concentration of a specific substance in the sample liquid can be measured. the sensitive film is formed by dropwise addition of a solution of the chemical sensitive membrane material, and you leave the coating film in a solvent atmosphere for dissolving or swelling the chemical sensitive membrane
Method of manufacturing a chemical sensor. 2. A solvent for dissolving or swelling a chemical sensitive film material solution same solvent der as Ru請 Motomeko 1 chemical sensor manufacturing method according. 3. A method for manufacturing a sensor plate comprising a substrate, at least one pair of which is provided with a sample liquid measuring electrode coated with a chemically sensitive film and a reference electrode, wherein the chemically sensitive film is made of this chemically sensitive film material. Formed by dropping the solution,
And Rousset down Sir plate manufacturing method to leave the coating film in a solvent atmosphere for dissolving or swelling the chemical sensitive membrane. 4. A solvent for dissolving or swelling a chemical sensitive film material solution and Ru same solvent der 請 Motomeko 3 sensor plate method according.