JPS59102153A - Ion selective electrode and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain an ion selective electrode easy in manufacture, good in water repellent property and high in efficiency by a method wherein an inner solution and an inner electrode are housed in a tubular body provided on the outer surface near the end thereof with an annular projected part and having an ion sensitive film bonded to a small hole at the other end thereof, the body being made of a hard insulating material. CONSTITUTION:A pressure contact rod 10 is vertically fixed at the center of a base plate 9, a spring 12 is wound round the rod and then an outer tube 11 is loosely fitted to the rod. A sensitive film 5 is placed on the upper end face of the outer tube 11, and a body 1 is turned upside down and then loosely fitted to the outer tube 11. A weight 13 formed with a hole of such a diameter as allowing it to be loosely fitted over the outer periphery of the body 1 is loosely fitted until the flange of the body. The spring 12 is compressed thus bringing the film 5 into contact with the inner surface of a film supporting part 3, so that the film 5 is surely bonded thereto with an adhesive previously coated on the film. The center of the film 5 is pushed by the spherical distal end of the pressure contact rod 10 to be slightly projected out. An inner solution and an inner electrode 7 penetrating through the center of a cap 8 are housed within the body 1. By so doing, it becomes possible to obtain an ion selective electrode easy in manufacture, good in water repellent property and high in efficiency.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an electrochemical electrode for quantifying ion concentration in a solution, and particularly relates to an ion electrode with a polymeric ion-sensitive membrane adhered to the internal reference liquid side of the electrode. This relates to selective electrodes.

[Prior art]

Conventional ion-selective charging electrodes of this type are fixed flat so that they are flush with the end surfaces of the two cylindrical ion electrode bodies due to the surface force of the ion-sensitive membrane.
However, due to the difficulties in making such electrodes, uniformity and reproducibility of their performance became a problem. Furthermore, when it is pulled up from the sample liquid, it is difficult to see through the liquid and a considerable amount of the sample liquid adheres to it, so it is necessary to wash and wipe it off each time. Additionally, the process of attaching the ion-sensitive membrane to the flat lower end surface of the tubular body was inefficient and unreliable.

[Purpose of the invention]

The present invention eliminates the drawbacks of the prior art described above and provides an ion selective electrode that is easy to manufacture, has good liquid drainage, and has high performance, and a method for manufacturing the same.

[Summary of the invention]

The first feature of the present invention is that the outer surface near the end has a flange-like annular protrusion, and the other end is made to protrude slightly toward the center, and a small hole is formed in the cross section of the tip. A tubular body made of hard insulating material, and an ion-sensitive membrane bonded inside the tube to seal the small holes in this body.
An ion selective electrode is constituted by an internal liquid housed in a body whose lower end is sealed with this ion exchange membrane and an internal electrode inserted and immersed in the center of the internal liquid.

Furthermore, the second feature resides in a novel manufacturing method for the above-mentioned ion-selective electrode. That is, the body formed as described above is turned upside down with the small hole facing upward, and the ion-sensitive membrane is placed on the upper end of the outer cylinder that fits into the inner surface of the body, and a crimping rod is attached to the lower end of the central hole of the outer cylinder with plywood. were fitted via a spring, and then a weight with a hole that fits on the outside of the body was inserted from above the body and locked to the collar-shaped annular protrusion, and the ion-sensitive membrane was coated with adhesive. After bringing it into contact with the inner surface of the small hole of the body and press-bonding it with the tip of the crimping rod, the outer cylinder, the crimping rod, and the weight 9 are removed.

Generally, in an ion-selective electrode, if there is a part of the ion-sensitive membrane that comes into contact with the sample liquid that does not operate effectively, the response speed of the electrode will be slowed down, but if such an ineffective part is on the internal liquid side of the electrode, does not cause slow response speed. In addition, by placing the effective part of the ion-sensitive membrane slightly protruding into the test liquid, it greatly improves the problem of liquid running out when the ion-selective electrode is taken out, and reduces stagnation in the flow of the test liquid. It was confirmed through experiments that the anti-contamination properties were also improved.

[Embodiments of the invention]

FIG. 1 is a vertical sectional view of an ion selection electrode according to an embodiment of the present invention. The body 1 is a housing for an ion selective electrode and is a tube made of hard vinyl chloride material. An annular membrane support part 3 having an inner hole 2 at the center and a small hole 4 at its lower end.
has been established. The part where the small hole 4 is formed is made thin and slightly protrudes like the tip of a tobiguchi, and an annular flange is formed on the outer periphery of the body 1 near the end surface on the opposite side of the small hole 4. There is.

An ion-sensitive membrane 5 is bonded to the membrane support 4 so as to seal the small hole 4 of the body 1 from the inside. This ion-sensitive membrane 5 is made of, for example, 20% trimethyldodecyl ammonium chloride as an anion-sensitive group, 10% dioctylazibet as a plasticizer, and 70% total polyvinyl vinyl.
It is mixed with the container side and spread to form a membrane. The upper part of this ion-sensitive membrane 5 is in contact with an internal liquid 6, and an internal electrode 7 is inserted into the internal liquid 6 and sealed with a lid 8.

The ion selective electrode constructed in this manner has the following advantages.

(1) Since the ion-sensitive membrane 5 slightly protrudes conically from the lower end of the body 1, when this ion-selective electrode is immersed in the test liquid, air bubbles easily escape from the membrane surface, and the test liquid When I pulled it up from the tank, the amount of test liquid attached was small and it was obvious that the liquid had run out. Therefore, measurement values will not be inaccurate due to air bubbles, and washing operation after use becomes easy.

(2) Since the ion-sensitive membrane 5 protrudes into the test liquid, the contact membrane area is large, and the test liquid easily contacts this surface and moves. Therefore, the response speed of the electrode becomes faster.

(3) The ion-sensitive membrane 5 can be easily and reliably attached to the body 1 by the following manufacturing method, and stable measurements can be performed for a long period of time. This will be explained in detail next.

Conventionally, the ion-sensitive membrane 5 was adhered flatly to the flat end surface of the body 1 using an adhesive or a mounting ring. When the ring was located at the periphery, air bubbles could get caught in this area and become stagnant, reducing sensitivity and responsiveness. Furthermore, the mounting process performed by the manufacturer of the ion-sensitive membrane 5 has the disadvantage of being inefficient because most of the work is done manually.

FIG. 2 is an explanatory diagram of the work of attaching the ion-sensitive membrane to the body of FIG. 1. First, a crimp frame 10 having a hemispherical tip is fixed vertically at the center of the base plate 9, and a spring 12 is wound around the outer cylinder 11. The outer diameter of the body 1 is dimensioned so as to fit loosely with the inner surface of the body 1. Place the base plate 9 on a horizontal surface, make the crimp frame 110 stand upright, place the ion-sensitive membrane 5 having the same outer diameter on the upper end surface of the outer tube 11, then turn the body 1 upside down and gently hold the outer tube. 11, and a heavy shell 13, which has a hole sized to fit on the outside of the body 19 from the upper part, is silently fitted to the flange. Therefore, the spring 12 is compressed by the weight of the heavy shell 13 and brings the ion-sensitive membrane 5 into contact with the inner surface of the membrane support part 3. Tetrohydrofuran, which is an adhesive between the ion-sensitive membrane 5 and the body 1, has been applied to the inside of the membrane support part 3 in advance, so that they are adhered to each other. At the same time, the spherical tip of the crimp frame 10 presses the center of the ion-sensitive membrane 5 to slightly protrude from the small hole 4.

In the above operation, if the weight of the heavy plate 13 is determined appropriately, the adhesion strength of the ion-sensitive membrane 5 to the inner surface of the membrane support part 3 and the protrusion size from the small hole 4 can be made constant. .

That is, it is possible to mass-produce ion selective electrodes with the same performance, and the manufacturing efficiency can be greatly improved.

As described above, the ion-selective electrode of the present example is provided with a membrane support part whose tip of the body made of hard vinyl chloride projects obliquely, a small hole is formed at the tip, and an adhesive or an organic solvent is applied to the inner surface of the membrane support part. The ion-sensitive membrane is coated with adhesive so that the center part of the ion-sensitive membrane slightly protrudes, which improves the contact with the test liquid and improves the response speed.The membrane also drains well when pulled up and is easy to clean. . Further, it has the advantage that it is easy to manufacture and can efficiently provide products with excellent performance.

FIG. 3 is a vertical sectional view of an ion selection electrode according to another embodiment of the present invention, in which the same parts as in FIG. 1 are given the same reference numerals. In this case, a plurality of ion-selective electrodes are attached to one block 15, and the lower surface of the ion-sensitive membrane 5 slightly protrudes into the flowing test liquid flow path 14. Therefore, the contact with the test liquid is good, and the same effect as the embodiment shown in FIG. 1 can be obtained.

〔Effect of the invention〕

The ion-selective electrode of the present invention has eight advantages when the protrusion of the ion-sensitive membrane has good contact with the sample liquid, improving response speed, draining the liquid well, and being easy to manufacture. It will be done.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of an ion-selective electrode according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of the work of attaching an ion-sensitive membrane to the body of FIG. 1, and FIG. 3 is an illustration of another embodiment of the present invention. FIG. 2 is a vertical cross-sectional view of an ion selective electrode according to an example.

Claims (1)

[Claims] 1. A hard insulation having a brim-like annular protrusion on the outer surface near the end, and the other end slightly protruding toward the center and having a small hole formed in the cross section. a tubular body made of wood; an ion-sensitive membrane adhered to the inside of the tube so as to seal the small holes of the body; and an internal liquid contained in the body whose lower end is sealed with the ion exchange membrane An ion selective electrode comprising an internal electrode inserted and immersed in the center of the ion selective electrode. 2. A tubular body made of hard insulating material that has a brim-like annular protrusion on the outer surface near the end, and the other end slightly protrudes toward the center and has a small hole with a tortoise-shaped cross section. Turn it upside down so that the small hole is facing upward, place the ion-sensitive membrane on the upper end of the outer cylinder that fits into the inner surface of the body, and insert a spring into the center hole of the outer cylinder with a fixing rod with plywood attached to the lower end. Then, a heavy cylinder having a hole that fits into the outside of the body is inserted from above the body and locked to the brim-shaped annular protrusion, and the ion-sensitive membrane is attached with adhesive. Fabrication of an ion selective electrode characterized in that the coated inner surface of the small hole of the body is contacted and the tip of the fixing rod is pressed and bonded, and then the outer cylinder, the fixing rod, and the weight are removed. Method. 3. The method of manufacturing an ion selective electrode according to claim 2, wherein the fixing rod is a rod having a gently protruding surface formed at the tip that contacts the ion-sensitive membrane.