JPS63201562A - Reference electrode - Google Patents

Abstract

PURPOSE:To stabilize inter-liquid potential with a reference electrode of an open liquid junction system by forming a sample flow passage to a crank shape in a vertical direction and opening an inflow port for a reference electrode liquid on the vertical of the crank part of the sample flow passage. CONSTITUTION:A cell body 1 and the internal liquid sealing type reference electrode 2 consisting of the liquid film are mounted. A sample liquid inlet 3, a sample liquid outlet 4, a reference electrode liquid inlet 5, the sample flow passage 9 having the crank and reference electrode liquid flow passage 19 are provided. The aperture 9 of the flow passage 19 is provided on the vertical of the crank part of the sample flow passage 9. The fall of the reference electrode liquid having a large sp. gr. toward an ion electrode by passing the sample flow passage during measurement is prevented by constituting the electrode in such a manner; in addition, the arrival of the component such as, for example, blood cells, in the sample, at a permeable film 12 and the consequent fluctuation of the inter-liquid potential are prevented as well.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an open flow path type reference electrode, and particularly to a reference electrode in which the potential of the liquid contacting surface of the flow path portion is stable and is suitable for small-volume analytes. 6 [Prior art] As a conventional comparison electrode of this type, H, F 0ssvo
There is a reference electrode of LD (Diss-ETH6480 Note)
en ) lochshule Zurich Juri
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79). There is also one shown in Utility Model Application Publication No. 59-29759.

[Problem that the invention seeks to solve]

However, with the above H-F Osswold reference electrode, a sample is poured from above into a φ0.8m11 sample channel placed vertically in a straight line, and a comparison is made from an obliquely downward direction into the middle of the sample channel, which is narrower than the sample channel. By pouring the electrode liquid, disturbances on the surface in contact with the liquid are minimized.

However, air bubbles may adhere to the joint for guiding the reference electrode solution into the narrow channel, and microbubbles may occasionally flow into the channel, or microscopic contaminants in the reference electrode may block the narrow channel.
There was a drawback that the stability of the mill for a long time could not be obtained.

Furthermore, the device described in Japanese Utility Model Application Publication No. 59-29759 is characterized in that an on-off valve is provided in the reference electrode liquid flow path or the sample flow path to prevent disturbance of the surface in contact with the liquid.

However, if there is a difference in specific gravity between the sample solution and the reference electrode solution, long-term stability on the contact surface cannot be obtained, and
When pressure fluctuations occur in a flow path without an on-off valve, there are drawbacks such as turbulence at the connection surface instantaneously.

Other conventional examples include those constructed as shown in the vertical sectional view of FIG. 4 and the bottom view of FIG. 5.

This is because the difference in specific gravity between the sample liquid and the reference electrode liquid has been improved by making the reference electrode flow path 29 longer, but problems due to air bubbles in the reference electrode liquid, Problems caused by air bubbles in the standard solution supplied from the inlet 27, reference electrode 22. No consideration was given to the lifespan of the ground electrode 21, and there was a problem with the reliability of the device.

The reason for the generation of bubbles is that while the supplied reference electrode solution and standard solution are at room temperature or below, inside the device the temperature rises to 40 to 50 degrees Celsius due to heat dissipation from various electrical components. This is due to changes in temperature, such as when the air in the air becomes supersaturated and forms bubbles as the temperature rises, and due to changes in the diameter of the piping, which causes turbulent flow inside the flow path.
This is due to physical changes in the channel system within the device, such as the generation of bubbles at this time. Furthermore, since the sample channel 28 in the reference electrode cell 20 is bent at a right angle, air bubbles in the reagent provided by the sample population 27 may not be completely removed. Generally, the configuration of the flow path of an ion concentration analyzer is required to be vertical in consideration of air bubbles and the like.

In the case of the comparison electrode cell 20 shown in FIG. 4, the comparison electrode 22.
A ground electrode 21 is inserted into the cell.

In order to increase measurement sensitivity, the electrode surface area is taken as much as possible, and the flow path diameters are different as shown in the figure. Furthermore, the flow path is in the shape of a dead end. For this reason, once fine air bubbles are mixed in, they accumulate in the corner portion (portion A), making accurate measurement impossible.

An object of the present invention is to eliminate the influence of fine bubbles in the reference electrode solution and standard solution supplied into the reference electrode cell.

It is an object of the present invention to provide a reference electrode which can obtain a stable liquid junction potential despite some disturbance of the liquid contacting surface of a liquid junction and is suitable for a small amount of sample.

[Means for solving problems]

The above object is achieved by making the sample channel vertically crank-shaped and opening the reference electrode liquid inlet vertically above the crank part.

[Effect]

The sample channel is shaped like a crank in the vertical direction, and the inlet for the reference electrode solution is opened vertically above the crank part.

This eliminates disturbances on the wetted surface due to differences in the specific gravity of the sample and the reference electrode solution, as well as the influence of the reference electrode solution falling onto the ion concentration detector.
No more erroneous measurements.

〔Example〕

Hereinafter, one embodiment of the present invention will be explained in the vertical cross-sectional view of FIG.
This will be explained with reference to a non-sectional view of the figure.

In the figure, 1 is a reference electrode cell body, 2 is an internal liquid seal liquid film reference electrode, 3 is a sample liquid inlet, 4 is a sample liquid outlet, and 5
8 is the reference electrode solution inlet, 8 is the opening between the sample and the reference electrode solution,
9 is a crank passage section.

The sample flow path and the reference electrode liquid flow path 19 have a structure that minimizes changes in the inner diameter to prevent any air bubbles from accumulating.
The inner diameter is approximately φ1m.

The present invention will be explained in detail with reference to FIG. Sample liquid outlet tube 13
For example, there is a potassium ion monopole 14 having a sample inlet tube 16 below the comparison electrode 2 where the sample inlet tube 16 is disposed. The signal line 15 of the potassium ion monopole 14 is connected to the electrode 2a and the ground llA18.
It is electrically processed by an electric circuit 17 provided between.

Next, the present invention will be explained in detail. When human whole blood now flows through the sample inlet tube 16 to the sample outlet tube 13 to fill the system, the flow stops. Next, the reference electrode solution flows from the reference electrode inlet 5 toward the sample outflow tube 13 . From that point on, a potential difference appears that corresponds to the potassium ion concentration. Generally, when measuring with an ion electrode, a constant potential is required for about 30 seconds.

Now, near the opening 8, the reference electrode solution, generally a potassium chloride aqueous solution with a concentration of 1 molar, is large compared to the whole blood, so the specific gravity is large. For example, the potassium ions fall within 30 seconds and reach the potassium ion monopole 14, causing an error. Additionally, it is possible to extend the sample flow path vertically to the extent that it does not affect the potassium ion monopole 14 within the measurement time, but generally in emergency testing equipment, the amount of sample used is limited to 100 μa. This amount will increase considerably.

Creating a crank shape, which is unrealistic, means that the reference electrode solution will not fall in the horizontal part of the flow path, and even if the solution moves, it will not fall within the measurement time. The capacity inside the crank can be reduced to 13 μQ or less, and there is no need to increase the number of samples used.

The potassium ion concentration in human whole blood is about 5 mmol, and if we can only tolerate an error of about 0.1 mmol, then 1/10,000 of the potassium chloride aqueous solution should not fall, and the specific gravity of the potassium chloride aqueous solution Because the specific gravity of blood cells is high.

If the flow path 19 is inclined downward on the side of the reference electrode solution 5 compared to the horizontal position, blood cells fall from the sample outlet 13 and reach the permeable membrane 12, and a salt bridge is no longer formed. However, if the sample flow path is crank-shaped as in the present invention, the potassium chloride aqueous solution becomes a potassium ion monopole within the measurement time.
4, and even if there is some pressure fluctuation, the blood cells will not reach the permeable membrane.

Note that the opening 8 may be positioned anywhere vertically above or below the crank.

〔Effect of the invention〕

As is clear from the above description, according to the present invention.

A stable liquid junction potential can be obtained despite slight disturbances on the liquid contact surface of the liquid junction due to pressure fluctuations or differences in specific gravity, and the reference electrode liquid does not fall to other electrodes within the measurement time, and It is possible to obtain a reference electrode suitable for small-volume samples in which the liquid junction potential does not fluctuate due to falling blood cells during the measurement time.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a comparison electrode according to an embodiment of the present invention;
FIG. 2 is a bottom view of a comparison electrode according to an embodiment of the present invention, FIG. 3 is an explanatory diagram of an example of use of the embodiment, FIG. 4 is a vertical cross-sectional view of a conventional comparison electrode, and FIG. 5 is a comparison of a conventional comparison electrode. FIG. 3 is a bottom view of the electrode. DESCRIPTION OF SYMBOLS 1... Comparison electrode cell body, 2... Internal liquid doll liquid film comparison electrode, 9... Crank channel section, 5... Comparative electrode liquid population 212] Figure 5, Port 3

Claims (1)

[Claims] 1. Comparison of an open liquid junction type reference electrode, characterized in that the sample flow path is configured vertically in the shape of a crank, and the inlet for the reference electrode liquid is opened vertically above the crank portion of the sample flow path. electrode.