JPS62849A - Ion concentration analyzing instrument - Google Patents

Abstract

PURPOSE:To use a reference electrode stably for a long period of time without mainte nance by feeding a liquid to be inspected and calibrating liquid in such a manner that the front ends thereof stop in the position between an ion selective electrode and reference electrode in a flow passage. CONSTITUTION:The calibrating liquid I is first fed into the flow passage 4, then again the same calibrating liquid is fed therein as the calibrating liquid II and thereafter the liquid 31 to be tested is fed into the passage 34. Both the liquid I and the liquid II in such a case are the same calibrating liquid at the point of the time when both liquids are fed into the passage but the liquid I plays the role of the internal liquid in the reference electrode 36 and the liquid II is used as the calibrating liquid for the ion selective electrode 37, by which the reference potential is calibrated. The liquid 31 is then introduced into the passage by the operation of a cock 32 and this time the liquid II plays the role of the internal liquid of the electrode 36 and the boundary point A between the liquid 31 and the liquid II plays the role of a liquid junction part when the front end of the liquid to be tested stops at the point A. The liquid I and the liquid II are further fed into the passage and the analysis is repeated. The reference electrode is thereby stably used for a long period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an ion concentration analyzer that includes an ion-selective electrode and a reference electrode in a flow path for a sample liquid.

More specifically, the present invention relates to an ion concentration analyzer in which a reference electrode can be used stably over a long period of time and without maintenance.

[Technical background of the invention and its problems] Ion-selective electrodes have the feature of being able to selectively quantify the concentration of specific ions in a liquid, and have been used in a wide range of fields such as monitoring specific ions and analyzing water quality. ing.

This is because there is a linear relationship between the potential shown by the ion-selective electrode and the logarithm of the target specific ion concentration, and the target ion concentration can be easily calculated from the measured potential. In recent years, these ion-selective electrodes have come to be used for medical purposes, especially for quantifying various ions such as Na'', K+, and CI- present in blood. Many types of analysis devices are also manufactured.

By the way, in the measurement method using such an ion-selective electrode, when measuring the ion concentration in the sample solution, in addition to the ion-selective electrode, a reference electrode that generates a reference potential is required. . Such a reference electrode is configured to electrically conduct an internal liquid contained therein with the test liquid through its liquid junction.

Figure 3 shows an example of a reference electrode that has been widely used in the past. In Figure 3 1c, 11) is an internal group? S electrode.

(2) is the internal liquid, and (3) is the liquid junction. Internal liquid (2)
Since the liquid is diffused to the outside through the liquid junction (3) and consumed, the internal liquid is added and used from the replenishment port (4) at an appropriate time. The liquid junction (3) of such a conventional deaf reference electrode gradually diffuses the liquid (3) inside the glass fiber or ceramic porous body. Plugs or pinholes are used to maintain gas continuity; however, in the case of test liquids containing a large amount of protein or organic components, such as blood or urine, the liquid junction may be damaged due to the adhesion resistance of the test liquid components. The problem was that it did not function properly due to dirt or blind spots. In order to prevent such accidents such as clogging of the liquid junction, an analyzer having a configuration example as shown in FIG. 4 has been manufactured. In Figure 2, the liquid junction (3) is completely held in place by a three-way cock, etc., and there is no problem of clogging, but a large amount of internal liquid (2) is always pumped with an internal liquid tank (5) Due to (6), there is a waste of having to refill the reference electrode tank (where the internal reference electrode (1) is located) from the refill port (4).Furthermore, the equipment is complicated and large, including the addition of piping and pumps. It also had the disadvantage of being uneconomical.

[Purpose of the invention]

The present invention has been made in order to eliminate the above-mentioned drawbacks, and is aimed at making the reference electrode provided in the flow path of the test liquid stable over a long period of time.
Moreover, it is an object of the present invention to provide an ion concentration analyzer that can be used without maintenance.

[Summary of the invention]

As a result of intensive research to achieve the above object, the present inventors provided an internal reference electrode for the reference electrode in the flow path of the test liquid, and added the calibration solution of the ion-selective electrode as the internal solution to the flow path. The present inventors have discovered that if the calibration solution is used by filling the inside of the calibration solution, the internal solution is inevitably replenished because it is always replaced with a new calibration solution.

That is, the ion concentration analyzer of the present invention includes: a flow path for transporting a test solution and a calibration solution; an ion-selective electrode and a reference electrode arranged so as to form part of the inner wall of the flow path; a mechanism for feeding the nuclear test solution and the calibration solution so that the tips of the solution stop at a position between the ion-selective electrode and the reference electrode in the flow path; It is characterized by being a liquid.

The ion selective electrode according to the present invention is N a", K".

An ion-selective electrode such as Cat+ or CI-, and the reference electrode refers to a saturation power Omel electrode, a silver/silver chloride electrode, or the like.

The calibration solution and internal solution according to the present invention have the same composition, and function as calibration when in contact with the ion-selective electrode, and as an internal solution when in contact with the base 1 electrode. An ion concentration analyzer in which the ion selective electrode and the reference electrode according to the present invention form a part of the flow path for the test liquid, and the calibration liquid is configured to play the role of an internal liquid. It has a configuration as shown in Figure 1. In FIG. 1, a test liquid (31) is introduced into a flow path C, 34) via a cock (32) by a pump (33). This is the calibration solution (3
The same applies to 5). The tips of both the test liquid (31) and the calibration liquid (35) are introduced into the flow path (34) at position A by one suction operation of the pump. For example, the order of introduction of solutions is firstly the calibration solution (I) sent in → the same calibration solution sent again (I[) → in the case of the test solution, the calibration solution CI, ) →
At the time of calibration liquid (I[), both are the same calibration liquid, but the calibration liquid (I) serves as the internal liquid of the reference electrode (36).

The calibration solution (II) is used as a calibration solution for the ion-selective composition ffl C, 37) to calibrate the reference potential. When the test liquid is introduced by operating the cock (32) and the tip stops at point A, the calibration liquid (II) that was just used will serve as the internal liquid of the reference electrode (36) and will be mixed with the test liquid. The boundary of the calibration solution (point A) serves as a liquid junction, and the calibration solution (I) and calibration solution (II) are sent in for repeated analysis.The ion-selective electrode shown in Figure 8g1 37) may be a flow-through type ion-selective electrode with multiple items rather than a single item.Also, the reference electrode may be installed upstream of the ion-selective electrode, or the calibration solution Alternatively, a KCI saturated solution or the like may be used.

The structure of the liquid junction, which is the boundary between the ion-selective electrode, the reference electrode, and the solution, provided to form a part of the flow path will be described in more detail. An example of this is shown in FIGS. 2(a) and 2(b). In FIG.
is provided. If the solution filled in the flow path (34) is a calibration solution on both the Bglll and C sides, cgtg
The calibration liquid becomes the internal liquid of the reference electrode (36), and the liquid junction (
The ion selective electrode (37) will be calibrated via the point A). Also, the B side is the test liquid.

When the C side is the calibration solution, the ion concentration in the test solution will be measured. In addition, as shown in Figure 2 (b), if the solution on the B side and the solution on the C side are cut off by air bubbles and it is difficult to form a liquid junction (point A), a salt bridge (39 points) is provided in advance. Just leave it there.

If the analyzer has the above configuration and series of operations,
It has the advantage that the liquid junction does not get clogged, and the internal liquid does not consume too much electricity and can also be used as a calibration liquid, so it can be used stably over a long period of time without maintenance.

[Embodiments of the invention]

Embodiments of the present invention will be described in more detail below with reference to FIG.

In the apparatus shown in FIG. 1, first, a calibration liquid (35) is pumped through a cock (32) and a pump (33) into a flow path (
34) and stops at point A. Additionally, the next batch of calibration fluid (35) is introduced into the flow path by the pump. Calibrate at this time. Next, the test liquid (31) is introduced by switching the cock (32) and stopped at point A.

At this time, the ion concentration of the test liquid is measured. By performing the above series of operations, the ion concentration measurement is completed. In addition, a Teflon tube with an inner diameter of 1.3φ was used for the flow path used in this example, and the ion-selective electrode (
28 cm ion-selective electrode (37)
) and the reference electrode (36) was 8 cm. The ion selective electrode (37) contains bis-12- in polyvinyl chloride.
A plastic film type Na + selective electrode (diameter 1φ, coated wire type) containing Crown-4 ether was used. Further, the reference electrode used was one in which a silver chloride layer was formed by electrolytically oxidizing a chain line of 1φ. Also, the calibration solution is KCi −
o, 4mmoJ/, N a Cl m 12mmo
J7. The test solution used was serum diluted 10 times with a Tris-borate buffer solution.

In addition, the amount of sample liquid and calibration liquid sucked by the pump is 580
μ, and the tip of each solution was an ion-selective electrode (37
) and the reference electrode (37), so that it stopped near the middle of the 8 cm long Teflon tube, so that the measurement of each solution was not affected by the diffusion of ions from each other.Ion selective electrode (37) The potential difference between the reference electrode (36) and the reference electrode (36) is amplified, processed by the arithmetic unit (40), and output as an ion concentration.

When 30,000 samples of serum were analyzed using the ion concentration analyzer described above, stable measurements were possible without any clogging of the liquid junction.

Furthermore, since the internal solution is a calibration solution structure and has a composition close to the ion concentration of the test solution, the internal solution of a conventional reference electrode (for example, the ion pair concentration in saturated KC1, NH, C This was caused by the ion species being different from the ion pair concentration and ion species in the test liquid.It became possible to forcefully reduce the liquid junction potential difference, and the measured values became more accurate.

〔Effect of the invention〕

As detailed above, if the ion concentration analyzer of the present invention is used, the reference electrode will not become clogged.

Furthermore, stable ion concentration analysis can be performed over a long period of time without replenishing the internal electrolyte.

[Brief explanation of drawings]

1 and 2 are block diagrams of an ion concentration analyzer used in embodiments of the present invention and an enlarged sectional view of a portion thereof, and FIGS. 3 and 4 are reference electrodes and ion concentration analyzers widely used in the past. FIG. 1 is a configuration diagram showing an example of a device. 1.36... Reference electrode, 2... Internal liquid, 3. A...
・Liquid junction, 4...Internal liquid replenishment port %5...Internal liquid tank, 6°33...Pump, 7. ...Reference electrode tank, 3
DESCRIPTION OF SYMBOLS 1... Test liquid, 32... Cock, 34... Flow path, 35... Calibration liquid, 37... Ion selective electrode %
38...Bubble, 39...Salt bridge. 40...Amplification, arithmetic unit. Figure 2 Figure 3

Claims (1)

[Claims] A flow channel for transporting a test solution and a calibration solution; An ion-selective electrode and a reference electrode arranged so as to form a part of the inner wall of the flow channel; and the test solution that has flowed into the flow channel. and a mechanism for feeding the calibration solution so as to stop it at a position between the ion-selective electrode and the reference electrode in the flow path in which the tip of the calibration solution is disposed; An ion concentration analyzer characterized by: