JPS6227872Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrochemical cell, and particularly to a flow-through type cell suitable for use in an analyzer using an ion electrode or a gas electrode.

In recent years, electrochemical detectors such as ion selective electrodes and gas electrodes have been increasingly used to analyze electrolytes and gas components in fluids. A flow-through type measurement cell is used in a continuous monitor or an analyzer that continuously measures a large number of samples, which is arranged in a flow path so that the response surface of the electrode is in contact with the sample. Devices of this type find particular application in the fields of clinical chemistry and biochemistry. As a conventional flow-type measurement cell, there is an example (known example 1) in which an electrode is inserted into a flow-type measurement container having one sample introduction tube and four discharge tubes around it. In this example, the sample flows from the center of the surface of the response surface and diffuses to the periphery of the response surface, reaching the four discharge pipes, but the sample forms an irregular vortex flow between the four discharge pipes and is discharged. is not carried out smoothly. Furthermore, the cell capacity is relatively large, and it is difficult to combine a plurality of cells for multi-item measurement.

On the other hand, as a measurement cell that allows the combination of a plurality of electrodes, there is one in which one electrode and one block of measurement cells are pressed together and integrated (Known Example 2). Each cell has a sample flow path that directly communicates with the flow path and electrodes are arranged so that the response surface is in contact with the flow path, but this is not effective in terms of response speed because the sample flows parallel to the response surface. There is also an example (known example 3) that improves this. In this example, a cylindrical measurement cell has a sample inlet/outlet groove and a radial hole near the center, and a measurement chamber is formed at the bottom of the hole into which the electrode is inserted, so that the flow of the sample relative to the response surface is perpendicular. It has been improved to become. In known examples 2 and 3, it is difficult to match the sample inlet and outlet when joining the measurement cells;
Sample seepage may occur on the surface of each measurement cell, or flow stagnation may occur, leading to carryover and measurement errors. In addition, in known examples 1 and 3,
Because the flow path is complex, it is easy to get clogged with solid matter and other debris, and to remove it, each measurement cell or electrode section must be removed, which requires time and effort to maintain the device.

The purpose of the present invention is to provide a flow-through cell for electrochemical analysis that can improve the response speed of sample component measurement using electrochemical measurement electrodes, while also being able to easily remove accumulated substances in the galvanic flow path. It is about providing.

In the present invention, the flow rate of the sample liquid on the surface of the electrode membrane is increased by narrowing the sample flow path near the electrode membrane, thereby improving the response speed. The structure was such that the channel could be widened to discharge the accumulated matter outside the flow cell. That is, in the present invention, an electrically insulating protruding member is provided in the flow path so as to face the exposed membrane surface, and the top of the protrusion member is directed toward the membrane surface to protrude and retreat into the flow path. It is characterized by being provided with a position adjustment mechanism that can be adjusted.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a configuration diagram of a flow-through measuring cell according to an embodiment of the present invention. This measurement cell is equipped with three ion selection electrodes and one reference electrode.
The body 1 of the cell is made of an insulating transparent synthetic resin, and a straight sample flow path 2 with an inner diameter of 1 mm passes through the center thereof, and a pair of through holes 11 intersect with and pass through the flow path 2. -11', 12-12', 13
-13' and 14-14'. Through hole 11,
12, 13, 14 are replaceable ion selective electrodes 3, 4, 5 and a reference electrode 6, and ion sensitive membranes 3',
4', 5' and the porous diaphragm 6' are arranged so as to face the inside of the flow path, and the other through holes 11', 1
2', 13', and 14' have insulating protruding members 15,
16, 17, and 18 are attached. Each protruding member 1
5, 16, 17, and 18 can be moved by adjusting the support member 19 screwed into the measuring cell, and the conical or wedge-shaped tops are connected to the flow path 2.
It can be taken in and out. And the protruding member 15,1
6, 17, 18 are through holes 11', 12', 13',
14', and further O-ring 2
8 and spring 29 to maintain confidentiality. The ion-selective electrodes 3, 4, 5 have synthetic resin electrode bodies 20, 21, 22 which have ion-sensitive membranes 3', 4', 5' adhered to their bottom parts and which hold an internal electrolyte.
and Ag/AgCl electrode 24, lead wire connector 25
Each electrode is fixed to the measurement cell by screwing a fixing member 26. On the other hand, the flow-through reference electrode 6 has a porous diaphragm 6' at the bottom of the electrode body 23.
A reference electrode is inserted in place of the Ag/AgCl electrode.

In this embodiment, the protruding members 15, 16, 1
7 and 18 are protruded into the flow path 2 as shown in FIG. 1, the liquid flow is directed toward the sensitive membrane surface, and
Since the flow velocity on the membrane surface increases, it has the effect of increasing the response speed. Further, when solid matter accumulates near the protruding member, by pulling it down, the flow path becomes a direct pipe, and the solid matter can be easily discharged to the outside. Further, since the measurement cell is transparent, it is effective to see the position of the protruding member in the flow path 2 and the state of dirt.

Although various shapes can be used as the protruding member, some examples are shown in FIG. In Fig. 2 a to d, the protruding member 15 (only the shape of the top part is shown)
The inside of the flow path 2 is shown, and the left side is a cross-sectional view in the flow direction, and the right side is a cross-sectional view in the vertical direction of the flow. In the cases of Figure 2 a and b, the surface of the protruding member that the liquid collides with is inclined at an angle of 90° or more with respect to the flow.
Liquids change direction smoothly, and solids do not easily accumulate. In cases c and d, the protruding member 15 faces perpendicular to the flow, and the liquid acts more effectively on the sensitive membrane surface of the electrode, which is advantageous in terms of response speed. Furthermore, d indicates that the protruding member 15 has a curved apex, and when the protruding member is lowered and removed from the flow path 2, the curvature matches the flow path 2 and is effective when removing solid matter. be.

FIG. 3 shows another embodiment of the measuring cell of the present invention, in which a is a sectional view BB' in the flow direction of the liquid, and b is a sectional view AA' in the vertical direction of the flow. This is the first
Adjacent electrodes in the example shown in the figure are installed at an angle of 80° in the circumferential direction of the flow path,
Since the distance between the electrodes increases as the electrodes move toward the connector 25, the response portions at the tips of the electrodes can be brought sufficiently close to each other. Therefore, the flow path becomes shorter, the cell capacity can be reduced, and the effect is further increased.

Next, as a measurement example, the measurement cell in Fig. 3 above to which the protruding member shown in Fig. 2 a above is attached is used to measure the amount of blood in serum.
Na, K, and Cl were measured and the response speed was investigated. The sensitive membrane of the Na ⁺ electrode is a neutral carrier type Na
A sensitive group is dispersed in polyvinyl chloride. The sensitive membrane of the K ⁺ electrode consists of valinomycin dispersed in polyvinyl chloride as a potassium sensitive group. The sensitive membrane of the Cl ^- electrode is a quaternary ammonium salt dispersed in polyvinyl chloride.

Electrodes were made by welding each sensitive membrane to a polyvinyl chloride electrode body using tetrahydrofuran, and the Na ⁺ electrode, Cl ^- electrode, K ⁺ electrode, and reference electrode were attached in this order from the sample inlet of measurement cell 1. A liquid pump (not shown) is connected to the downstream side of this measurement cell 1, and two types of control serum (Pasonorm H
and L) were introduced alternately. FIG. 4 shows a signal in which changes in the potential difference (corresponding to the sample concentration difference) between the K electrode and the reference electrode are plotted against the time axis.
The straight line portion 30 is a signal corresponding to the pasonorm H, and the line portion 31 is a signal corresponding to the pasonorm L.

In Fig. 4, a is a signal measured by a conventional method in which the protruding member is pulled down and there are no protrusions in the flow path, and b is a signal when the top of the protruding member is brought out to the center of the flow path. In c, the protruding member is further raised to the top and brought closer to the sensitive membrane of the electrode. According to this example, there was a tendency that the closer the protruding member was to the sensitive membrane, the faster the response to concentration changes. Similar results were obtained for the Na electrode and the Cl electrode. However, if they are brought too close together, the flow path becomes extremely narrow, which can easily cause problems such as clogging with debris and fluctuations in flow velocity. Considering such a case, it is very effective that the cell is transparent so that the inside can be observed and the position of the protrusion can be varied.

In addition, various electrochemical detectors such as PH electrodes, oxygen electrodes, carbon dioxide electrodes, etc. can be applied to the flow-type measurement cell of the present invention, in addition to ion-selective electrodes. It is also fully applicable to gas samples.

According to the present invention, since the sample flow path can be narrowed during sample measurement, the flow rate of the sample liquid near the electrode membrane surface increases and the response speed is improved. Further, when there is accumulated matter in the sample flow path, the protruding member can be moved back to widen the sample flow path, so that the accumulated matter can be easily discharged to the outside of the cell.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of a measuring cell explaining one embodiment of the present invention, Fig. 2 is a diagram showing the shape of a protruding member applied to the embodiment, and Fig. 3 is a diagram showing another embodiment of the present invention. , FIG. 4 is a measurement example to show the effect based on the present invention. 1...Body of measurement cell, 2...Flow path, 3
~5...Ion selection electrode, 6...Reference electrode, 11
~14...Through hole, 11'-14'...Through hole, 1
5-18... Projection member, 20-23... Electrode body.

Claims (1)

[Claims for Utility Model Registration] 1. An electrode for electrochemical analysis that has a flow path through which a sample liquid passes, and is arranged such that the membrane surface of an electrochemical measurement electrode equipped with a membrane is exposed to the flow path. In the flow-through cell, an electrically insulating protruding member is provided in the flow path so as to face the exposed membrane surface, and the top of the protrusion member is directed toward the membrane surface to protrude and retreat into the flow path. 1. A flow-through cell for electrochemical analysis, characterized in that it is provided with a position adjustment mechanism. 2. A flow-through cell for electrochemical analysis, characterized in that the cell according to Claim 1 of the Utility Model Registration Claim has a cell body made of a transparent material.