JPS61250548A - Comparing electrode - Google Patents

Abstract

PURPOSE:To enable highly accurate measurement by applying stable reference potential, by almost perfectly setting the potential between a liquid specimen and an internal liquid to earth potential. CONSTITUTION:The comparing electrode cell 1 of an apparatus for chemically measuring the electrolyte in a liquid is constituted of an insulating material and an internal electrode 2 is inserted in an internal liquid flow passage 6 communicated with an internal liquid injection port 4 and the leading end part thereof is contacted with the internal liquid. A common electrode 3 is constituted of platinum and the leading end conductor part thereof is formed into a cylindrical shape so as to cover the whole of the liquid communication part of the confluent point 7 of the internal liquid from the injection port 4 and the liquid specimen from a liquid specimen injection port 5. A common electrode lead wire 8 is arranged to said electrode 3 and an ion electrode 10 is inserted in the liquid specimen flow passage 11 of an electrode cell 9. Then, the potential between the liquid specimen and the internal liquid is perfectly brought to earth potential and the reception of the effect due to a confluent state is eliminated and stable reference potential is imparted to enable highly accurate measurement.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a reference electrode, and in particular to a reference electrode used to maintain a reference potential when electrochemically measuring electrolytes in liquids such as blood and river water. The present invention relates to a reference electrode having a structure suitable for providing a stable reference potential even when the reference potential is present.

[Background of the invention]

FIG. 7 is an explanatory diagram of the structure of a conventional comparison electrode of this type. In FIG. 7, 1 is a comparison electrode cell, 2 is an internal electrode, and 12
is a common electrode, 4 is an internal liquid injection port, 5 is a sample liquid injection port, and the comparison electrode cell 1 has an internal electrode 2 and a common electrode 12.
are arranged, and an ion electrode 1o is arranged in the electrode cell 9. Now, when the internal fluid is poured from the internal injection port 4 and the specimen fluid is poured from the specimen fluid injection port 5, the specimen fluid and the internal fluid merge at the confluence point 7, and the ion electrode 1o and the internal electrode 2
A circuit is constructed between the two and can extract an amount proportional to the ion concentration contained in the body fluid as a voltage, thereby making it possible to measure the ion concentration.

By the way, in this case, a liquid potential is generated due to the confluence of the subject body fluid and the internal fluid at the confluence point 7, so generally the common electrode 12 is installed at the confluence point 7, and the common electrode 12 is connected to the ground potential KL-. 1C-Save.

However, since the flow and the diffusion state change depending on the concentration of the body fluid to be examined, the common electrode 12 having a conventional configuration has a disadvantage in that the interelectrode potential cannot be completely suppressed. Incidentally, as related to the comparison electrode shown in FIG. 7, there is Japanese Utility Model Application Publication No. 59-29759.

[Purpose of the invention]

The present invention has been made in view of the above, and its purpose is to provide a comparison that can provide a stable reference potential without instability of the liquid junction potential at the confluence point of the test liquid and the internal liquid. Our goal is to provide electrodes.

[Summary of the invention]

The present invention is characterized in that the reference electrode cell is made of an insulator, and the common electrode, which turns the inter-liquid potential caused by the confluence of the internal fluid and the sample fluid into an earth potential, has a conductive portion at its tip that is connected to the internal fluid. The main feature is that it is constructed in a large size so as to come into contact with the entire flow junction with the body fluid to be examined.

[Embodiments of the invention]

The present invention will be described below with reference to the embodiments shown in FIGS. 1 and 6 and the embodiments shown in FIG.
This will be explained in detail using FIGS.

FIG. 1 is a structural explanatory diagram showing one embodiment of a comparison electrode of the present invention. In Fig. 1, 1 is a comparison electrode cell made of an insulator, 2 is an internal electrode, 3 is a common electrode, 4 is an internal fluid injection port, and 5 is a sample body fluid injection port, the tip conductor is in contact with the internal fluid. It is maintained in a chemically stable state. The common electrode 3 is constructed using platinum, and its tip conductor portion is connected to the liquid at the confluence point 7 of the internal liquid from the internal liquid inlet 4 and the subject body fluid from the subject body fluid inlet 5. It is configured in a cylindrical shape to cover the entire junction, and is attached so that the tip conductor comes into contact with the liquid junction, and the potential changes due to the state of confluence (diffusion state) of the body fluid to be examined and the internal fluid. I try not to be influenced by it. 8 is a common electrode lead wire. Reference numeral 9 represents an electrode cell, and reference numeral 10 represents an ion electrode inserted into the sample fluid channel 11 of the electrode cell.

Next, what about the present invention? The function of the common electrode 3 in the reference electrode at the confluence point 7 of the body fluid to be examined and the internal fluid will be explained using an equal number of circuits and in comparison with the conventional method. Figure 2 is a schematic diagram of the flow path using a conventional comparison electrode, Figure 3 is its equivalent circuit diagram, Figure 4 is a schematic diagram of the flow path using the comparison electrode according to the present invention, and Figure 5 is its equivalent circuit diagram. The equivalent circuit diagrams are shown in Figures 2 and 4.
In the figure, the same parts as in FIGS. 1 and 7 are designated by the same reference numerals. In addition, in FIGS. 3 and 5, EJ is the potential of the confluence point 7, rl is the resistance of the confluence point 7, r2 is the resistance of the ion electrode 10, a8 is the total resistance of the sample body fluid, and Es is the resistance of the ion electrode 10. potential, RC is the resistance of the common electrode 12, gc is the potential of the common electrode 12, E is the potential of the internal electrode 2, R is the resistance of the internal electrode 2, AI, A2. A3 is an amplifier, ECt
, ECz is the potential of the common electrode 3, RCI and RC2 are the resistances of the common electrode 3, and Eo is the output voltage.

The potential EJ at the confluence point 7 of the subject body fluid and internal fluid in FIG. 2 is:
When the concentration of the body fluid to be tested, the flow at the confluence point 7, and the state of diffusion change, the common electrode 12 becomes a rod-shaped circuit such as A + Therefore, the output voltage Eo in FIG. 3 changes, causing measurement errors.

On the other hand, in FIG. 4 according to the present invention, the entire confluence point 7 of the body fluid to be examined and the internal fluid is widely covered by the common electrode 3, so the circuits shown in FIG. As, EJ, RC2, ECz.

The potential EJ of the confluence point 7 caused by the state is relaxed, and the change in the potential E8 of the ion electrode 10 is extracted as the output voltage E0, allowing highly accurate measurement.

In FIG. 1, the tip conductor portion of the common electrode 3 is configured in a cylindrical shape so as to cover the entire confluence point 7, but
As shown in the figure, it may be configured in a large plate shape so as to contact the entire flow point 7 of Otsu 3, and almost the same effect can be obtained.

〔Effect of the invention〕

As explained above, according to the present invention, the potential between the liquids at the confluence of the body fluid to be examined and the internal fluid can be made almost completely to the earth potential, and a stable reference potential can be provided. This has the effect of making it possible to measure accuracy.

[Brief explanation of the drawing]

FIG. 1 is a configuration explanatory diagram showing one embodiment of the comparison electrode of the present invention, and FIG. 2 is a schematic diagram of a flow path using a conventional comparison electrode.
FIG. 3 is an equivalent circuit diagram thereof, FIG. 4 is a schematic flow path diagram using the comparison electrode according to the present invention, FIG. 5 is an equivalent circuit diagram thereof, and FIG. 6 is a diagram showing another embodiment of the present invention. Configuration explanatory diagram, 7th
The figure is an explanatory diagram of the configuration of a conventional comparison electrode. DESCRIPTION OF SYMBOLS 1... Reference electrode cell, 2... Internal electrode, 3... Common electrode, 4... Internal liquid inlet, 5... Subject fluid inlet, 7... Confluence point, 8... ...Common electrode lead wire.

Claims (1)

[Scope of Claims] 1. An internal electrode in contact with an internal liquid in a comparison electrode cell used when electrochemically measuring an electrolyte in a sample body fluid, and a state in which the internal liquid and the sample body fluid join together. In a comparison electrode consisting of a common electrode that transforms the potential between liquids into an earth potential, the comparison electrode cell is made of an insulator, and the common electrode has a conductor at its tip that connects the internal liquid and the sample liquid. A comparison electrode characterized in that it is constructed in a large size so as to come into contact with the entire flow section between the electrode and the electrode. 2. The conductor portion at the tip of the common electrode is configured in a cylindrical shape so as to cover the entire liquid junction portion.
Reference electrode as described in section.