JPS5914761Y2 - Composite electrode for flow-type ion measurement - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a composite electrode for flowing ion measurement.

As shown in FIG. 1, this composite electrode has an inner electrode 1 and an inner liquid 3 inside an outer tube 5 which is usually made of a glass tube and has an enlarged lower end.
A sensitive membrane 7 formed in a capillary shape made of glass or the like having a composition sensitive to ions is enclosed at the enlarged lower end of the outer tube 5.
A detection electrode A is formed integrally with the outer tube 5 through the inner surface of the sensitive membrane 7, and the outer tube 6 is usually made of a glass tube.
The inner electrode 2 and the internal liquid 4 are sealed inside, and the lower end of the outer tube 6 is connected to one end of the sensitive membrane 7 so as to communicate with the inside of the sensitive membrane 7. It consists of a comparison electrode B that is integrally provided with the tube 6 and has a liquid junction 9 formed on the side farthest from the inner pole 2 of the communicating tube 8 in the outer tube 6.
An inlet pipe 10 connected to the other end of the sensitive membrane 7 is provided integrally with the outer tube 5.

The test liquid is used by flowing into the sensitive membrane 7 from the inlet pipe 10 so that the internal liquid 4 consisting of the KC1 solution flowing out from the liquid junction 9 does not flow toward the sensitive membrane 7.

In such a composite electrode for flow-type micro ion measurement,
If air bubbles are mixed into the test liquid, they will not affect the measured value in any way while they are passing through the sensitive membrane 7 of the sensing electrode A, but from the point where they exit the sensitive membrane 7, they will enter the liquid junction. If air bubbles arrive between part 9 and 9, the air bubbles will cause the detection electrode A and comparison electrode B
They are electrically isolated from each other, and measurements cannot be taken until a bubble passes between them.

The purpose of this invention is to provide an improved composite electrode for flow-through type ion measurement that does not interfere with measurement even when air bubbles are mixed in the sample liquid.

In order to achieve this objective, the present invention has set the inner diameter of the communicating tube 8 to be 2 to 3 times the inner diameter of the sensitive membrane 7 from the part in contact with the outer tube 5 to the part penetrating the outer tube 6, as shown in FIG. It is formed to have a large diameter.

Note that the same parts in FIG. 2 as in FIG. 1 are indicated by the same symbols as in FIG.

In this way, the air bubbles that have passed through the sensitive membrane 7 occupy only a part of the pipe cross section in the communication pipe 8, and do not occupy the entire pipe cross section, so that the air bubbles located below the bubbles are The connecting part and the bubble no longer come into contact with each other, and the detection electrode A and the comparison electrode B are electrically isolated by the bubble, so that the electrode device can be replaced without causing a state in which measurement is impossible.

The effect of the present invention is even clearer when looking at FIG.

That is, the inlet tube 1 of the electrode as shown in FIGS. 1 and 2.
When the test liquid was sent from zero using a microtube pump or the like, the ionic activity of the test liquid was continuously measured using the electrode shown in Figure 2 according to the present invention, and the results looked like a straight line A. When the same measurement is performed using the electrode shown in Figure 1, each time a bubble passes between the sensitive membrane and the liquid junction, as shown by the curved line, there is a large increase regardless of the change in the ionic activity of the test liquid. A potential change occurred.

It goes without saying that the sensitive membrane may be a glass membrane selectively sensitive to sodium ions in addition to the PH glass sensitive membrane, or an ion electrode for measuring various ion activities.

[Brief explanation of the drawing]

FIG. 1 is a partially cross-sectional side view of a conventional composite electrode for flow-through ion measurement, FIG. 2 is a partial cross-section side view of the present invention's composite electrode for flow-through ion measurement, and FIG. 3 is a graph showing a comparison of the results of successive measurements of ion activity using each electrode in FIG. 2. FIG. 1.2...Inner pole, 3,4...Inner liquid,
5, 6...Outer tube, 7...Sensitive membrane, 8.
...Communication pipe, 9...Liquid junction, 10...
...Inlet pipe, A...Detection electrode, B...
- Reference electrode.

Claims (1)

[Scope of utility model registration request] An inner electrode and an internal liquid are sealed inside the outer tube, and a sensing electrode is installed integrally with the outer tube by penetrating a sensitive membrane formed in a tubular shape at the enlarged lower end of the outer tube. A liquid is sealed in the outer tube, and a communication tube connected to the lower end of the outer tube so as to communicate with the inside of the tubular sensitive membrane is passed through and integrated with the outer tube. In a composite electrode consisting of a reference electrode and a reference electrode forming a part, the inner diameter of the communicating tube connected to the tubular sensitive membrane so as to communicate with the outer tube of the sensing electrode is penetrated through the outer tube of the comparison electrode from a portion adjacent to the outer tube of the sensing electrode. A composite electrode for flow-through ion measurement characterized by having a diameter larger than the inner diameter of a tubular sensitive membrane.