JPS5868659A - Ion selective electrode - Google Patents

Abstract

PURPOSE:To provide an ion selective electrode which has a long life and a high reliability, by a method wherein an internal reference electrode and a conductive material surrounding the electrode are sealed in a cylindrical plastic, and an ion selective film containing a plasticizer, which has its extending part in the conductive material, is formed at the forward end of the cylindrical part. CONSTITUTION:A shielding wall 13 is located at the inside of a cylindrical receptacle made of plastic such as polyvinyl chloride, an internal reference electrode 12 and a conductive material 14 such as KCl surrounding the electrode are sealed therein, and the electrode is connected to the outside through a lead wire 16. In the case of a K<+> selective film, an extending part 17 is formed at the forward end of the cylindrical receptacle and at a peripheral part of a selective film 15, in which valinomycin, serving as a carrier, is secured in plastic togetherwith a plasticizer, i.e., dioctyl adipate, and the extending part is placed in the conductive material to adhere together them. A plasticizer, which gradually diffuses into a measuring liquid, is supplied to the film 15 from the extending part, and this obtains a long life ion selective electrode.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ion-selective electrode for selectively measuring the concentration of specific ions.

Conventionally, ion-selective electrodes have the characteristic of being able to selectively fix the concentration of specific ions in a liquid, and have been used in a wide range of applications, such as monitoring the concentration of specific ions and analyzing water quality. Ta.

For example, in the case of a cation-selective electrode, the difference between the active 11a+ of the cation and the potential E shown by the cation-selective electrode is E-B@+2.303(RT/ZF)loga. ”・
=...-(t), and in the case of an anion-selective electrode, there is a difference between B -E and the potential E shown by the target ion-selective electrode. ”-2,303 (RT/ZF) log a-
This is because a relationship such as (2) in which the logarithm of the oil layer is proportional to the potential is established, and the activity of the target ion can be easily calculated from the measured value of the potential.

In the above equations (1) and (2)), R is a gas constant, T is a feed temperature, a ZFi ion valence, FJ''j7 is an Alade constant, and He is a standard electrode potential of the system.

By using an ion-selective electrode in this way, it is possible to quantify ions over a wide concentration range by simply measuring the first position.Also, by using an ion-selective electrode, the electrode part can be made smaller. This makes it possible to perform measurements with a small amount of sample.Due to the convenience of such ion-selective electrodes, they have recently been used for medical purposes, especially for measuring ions dissolved in blood, such as N.
a+, K+C! There have been many attempts to use it for quantifying ions such as -.

However, when an ion-selective electrode is used for a long time, the ion-selective membrane deteriorates and the membrane needs to be replaced, and it is often necessary to restore the electrode function at the time of replacement. In particular, in an ion-selective electrode having an ion-selective membrane in which a neutral carrier is contained in a plastic such as polyvinyl chloride together with a plasticizer, when this is used for analysis of blood, etc., the above-mentioned The plasticizer was preferentially extracted from the ion-selective membrane, resulting in a short lifespan.

An object of the present invention is to eliminate the drawbacks of the above-described neutral carrier type ion-selective electrode having a neutral carrier as an ion-selective substance.

That is, the present invention provides an internal reference electrode housed in a container, a highly conductive material sealed in the container to surround this electrode, and a plastic material or plastic material forming a part of the wall of the container. The present invention relates to an ion-selective frost-electrode, comprising an ion-selective membrane containing an ion-selective agent and an ion-selective substance, and an extension portion made of the same material as the ion-selective pattern of the lock.

In the ion-selective electrode of the present invention, even if the plasticizer is extracted from the surface of the ion-selective membrane in contact with blood, the plasticizer is supplied from the extension to the ion-selective membrane. As a result, the decrease in the degree of plasticizer inside the ion-selective mold is prevented, and the deterioration of the membrane is suppressed.

Hereinafter, the present invention will be explained by examples.

If you explain potassium ion selective electron & with a drawing,
An internal reference electrode 12 from a chain-silver chloride body housed in a substantially cylindrical container 1.l is supported by a shielding wall 13 that partitions and supports this electrode at the tip of the container. An internal electrolyte KC/
constitutes a part of the wall of the container with a conductive substance 14 consisting of
4. The neutral carrier palinomycin attached to the tip of the container is mixed with the OT plasticizer dioctyl adipate. nine potassium ion-selective membranes fixed in plastic to 15
and the internal reference electrode 12 and a lead wire 16 led out to the outside of the tube.
The ion-selective electrode has a structure in which the ion-selective membrane 15 protrudes inside a container in contact with the conductive substance 14 and is provided with an extension portion 17 made of the same material as the ion-selective membrane. When the potassium ion selective electrode of the present invention having the structure was actually measured,
It exhibited a Nernstian response in the K+ concentration range of 10-'M to 5x10-sM and had a lifespan of 6 months in serum. In contrast, conventional potassium ion selective electrodes have a lifespan of about 1 to 2 months.

As mentioned above, since the electrode of the present invention has a Nagasaki life in blood analysis, using the electrode of the present invention reduces the need for electrode replacement, which conventionally had to be done frequently, and the number of recreational measurements. It also has the advantage of being able to reduce

[Brief explanation of drawings]

The drawing is a cross-sectional view of an ion-selective 'fIL pole according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 11-1 container, 12... Internal reference electrode, 13... Shielding wall, 14... Conductive substance, 15... Ion selective membrane, 16... Lead wire, 17... Extension part .

Claims (1)

[Claims] A conductive material that is housed in a container and is sealed in the container so as to surround the specific internal reference electrode and the t-pole, and a plastic material, a lubricant, and an ion-selective material that constitute a part of the wall of the container. An ion-selective electrode comprising: an ion-selective membrane comprising: an ion-selective membrane comprising: an extension portion made of the same material as the ion-selective membrane at a portion where the ion-selective membrane contacts the conductive substance;