JPS60205360A - Method for measuring trace component contained in liquid to be measured - Google Patents

Abstract

PURPOSE:To measure exactly ion species of trace concn. as well by dispensing an eluate corresponding to the peripheral part of the peak of a trace component and analyzing again the eluate by ion chromatography using a concentrating column. CONSTITUTION:The elutate corresponding to the peripheral part of the peak of an ion species of trac concn. is dispensed and the eluate is again analyzed by ion chromatography. The ion species of trace concn. having a small peak eluting near the ion species of high concn. giving a large peak can be thereby measured exactly. The easy and exact quantitative determination of the oxalate ion, etc. contained in human urine is thus made possible without disturbance by the peak of the main componet. Useful information for the purpose of qualitative determination and identification is also obtainable if the dispensed liquid is analyzed by using another separating column having a different separating mode.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring trace components in a liquid to be measured using ion chromatography.

FIG. 1 is a diagram for explaining a conventional example of such a method. In FIG. 1, tank 1 is
The i1F syneresis in a is pump 2a → first and second connection ports 3a, 3b of sample pulp 5 → separation column 4 →
It flows through the flow path of the inner chamber 5b in the suppressor 5 → the detector 6 → the waste liquid tank 1c. In addition, due to the liquid sending pump 2b, the removed liquid in the tank 1b flows through a flow path from the pump 2b to the outer chamber 5c in the sublet tank 5 to the waste liquid tank 1d. On the other hand, when a predetermined amount (for example, 5° 1 Jt) of the liquid to be measured is taken with a microsyringe and injected from the fourth connection port 3d of the sample pulp 5, the liquid to be measured is transferred from the fourth connecting hole 3d to the fifth connecting hole 3c. →Concentration column 3g
It flows through the flow path of →6th connecting hole 3f →5th connecting port 3e, and the ionic species in the liquid to be measured are captured in the concentration column 3g. In this state, when the sample pulp 5 is turned on, the connection states of the first to sixth connection ports 3a to 3f are switched from the solid line connection state in FIG. 1 to the broken line connection state. Therefore, the ion species in the concentration column 3g are transported by the eluent to the separation column 4, where they are subjected to a predetermined separation.

The eluate from the column 4 is led to the inner chamber 5b of the sublet chamber 5, where it comes into contact with the removal solution in the outer chamber 5C via the ion exchange membrane 5a, and undergoes, for example, cation exchange and changes in conductivity, etc. Pack ground is lowered. The eluate whose pack ground has been lowered in this way is led to the detector 6, where its conductivity is detected, for example, and then discharged to the waste liquid tank 1c. FIG. 2 shows a chromatograph in which the signals detected by the detector 6 in this manner are guided to a recorder (not shown) and drawn. By measuring the height and area of this peak (actually, measuring while changing the range so that all the peaks that are overlapping in Fig. 2 appear at the top on the chromatogram), each The concentration of species (S04, 0204, etc.) is measured.

However, in the above conventional example, the C20. ”
- It is difficult to accurately measure small peaks such as -, and there is a major drawback that it is impossible to accurately quantify ionic species at trace concentrations that elute near high concentration ionic species that give large peaks. .

The present invention has been made in view of these drawbacks, and its purpose is to provide trace component measurement that can accurately measure trace concentration ion species with small peaks that elute near high concentration ion species that give large peaks. K is to provide a method.

A feature of the present invention is that in a method for measuring trace components in a sample liquid using ion chromatography, an eluate corresponding to the area around the peak of the trace component is fractionated, and this eluate is used in a concentration column. The reason is that it was re-analyzed using ion chromatography.

Hereinafter, embodiments of the present invention will be described in detail using the drawings. The steps up to the point where a romatogram as shown in FIG. 2 is created using the apparatus shown in FIG. 1 are completely the same as in the conventional example, and therefore, redundant explanation will be omitted here.

Also, while looking at the chromatogram in FIG. 2, replace the waste liquid tank IC (3) in FIG. 1 with a preparative liquid tank (not shown) as follows. That is, the state pressure in Figure 1 is maintained from the starting point S in the chromatogram in Stripe 2 until just before time A when the peak of C2O4''-, which is a trace concentration ion species, appears, and at the same time, the waste liquid tank 1c is Minute 2- - Replace with the liquid collection tank. Also, from time A to 0204, the state shown in Figure 1 is restored). By replacing the tank in this way, from time A to B, The liquid discharged from the detector 6 is stored in the fractionated liquid tank.This fractionated liquid is injected into the concentration column 3g from the fourth connection port 3d of the injector 3 by using a microsyringe again. By the way, this fractionated liquid passes through the suppressor 5 shown in Fig. 1, and the eluent becomes an extremely weak electrolyte solution, resulting in a large drop in pack grounds such as electrical conductivity. Unlike the case where the sample solution containing the analyte is directly injected into the concentration column 3g, the ionic species are separated and eluted within the concentration column 3g due to the elution power of the eluent (4). transported,
At this point, a predetermined separation occurs. Further, the eluate from the column 4 is led to the inner chamber 5b of the suppressor 5, where it comes into contact with the removal liquid in the outer chamber 5C via the ion exchange membrane 5a to perform, for example, cation exchange.

For this reason, the eluent in the eluate is converted into an extremely weak electrolyte solution, resulting in a significant drop in pack grounds such as electrical conductivity. The eluent whose pack ground has been lowered in this way is led to the detector 6, where its conductivity is detected, for example, and then discharged to the waste liquid tank 1c. Fifth
The figure shows a chromatogram drawn by guiding the signal detected by the detector 6 in this way to a recorder (not shown).
)% 802-peak and co-peak are almost completely separated.

4. Also, by using this FIG. 3, the concentration of each ion species can be determined from the height and area of each peak, as in the case of FIG. 2. As is clear from a comparison between Figure 3 and Figure M2, C2O4, which is a trace concentration ion species in the liquid to be measured,
It can be seen that the measurement of '- can be made more accurately in FIG. 5 using the embodiment of the present invention.

According to the embodiment of the present invention as described in detail above, the eluate corresponding to the area around the peak of trace concentration ion species is fractionated and analyzed again by ion chromatography. It becomes possible to accurately measure trace concentration ion species with small peaks that elute near the high concentration ion species that give . Therefore, it has the advantage of easily and accurately quantifying citric acid ions (C204-) contained in human urine without being interfered with by the peak of the main component (e.g. 502- ions). be. Furthermore, there is also the advantage that more useful information for qualitative and identification purposes can be obtained than by analyzing the liquid fractionated as described above using another separation column with a different separation mode.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the trace component measuring method, FIG. 2 is a chromatogram created using the conventional example, and FIG. 5 is a chromatogram created using the embodiment of the present invention. 1a to 1d...tank, 2a, 2b... liquid pump,
6...Injector, 3g...Concentration column, 4.
... Separation column, 5... Suppressor, 5a... Ion exchange membrane, 6... Detector. Figure 2 Figure 3 5θ42-czθ42- 0 4 6 8 (mini

Claims (2)

[Claims] (1) A predetermined amount of the liquid to be measured is collected and transported to a separation column using an eluent to separate the ion species in the liquid to be measured, and the eluate from the column is transferred to a background remover by exclusive ion exchange. In the method of measuring a trace component in the liquid to be measured by removing a pack gland and then guiding the eluate to a detector to measure a physical quantity, the peripheral part of the trace component separated by the separation column. The eluate is fractionated downstream of the detector, the fractionated solution is injected into a concentration column to concentrate the trace components, and the trace component is then conveyed again to the separation column using the eluent. Component measurement method. (2) The physical quantity is electrical conductivity.
1) The trace component measurement method described in section 1).