JPS6391558A - High performance liquid chromatograph - Google Patents

Abstract

PURPOSE:To perform the regeneration of a suppresser column without interrupting analysis, by providing a flow passage change-over valve for introducing a definite amount of a regeneration liquid between an ion separation column and the suppressor column. CONSTITUTION:A flow change-over valve 5 having a weighing tube 5g is connected between a separation column 4 packed with a cation exchange resin and a suppressor column 6 packed with an anion exchange resin. The eluent in a tank 1a is allowed to flow by a pump 2a and a specimen is weighed by the weighing tube 5g to be introduced into a specimen change-over 3 and allowed to pass through the separation column 4 and the suppressor column 6 to be guided to a detector 7. When the eluent is allowed to continuously flow, the function of the suppressor column 6 is lowered and, therefore, the flow passage change-over valve 5 is periodically changed over and definite amount of the regeneration liquid in a tank 1c is weighed to be introduced into the column 6. By this method, the regeneration of the suppressor column can be performed without interrupting analysis operation.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a high performance liquid chromatograph that chromatographically separates and analyzes ions to be measured in a sample.

<Conventional technology> In a conventional high-performance liquid chromatograph, a fixed amount of sample is collected by a sample collection valve and transported to a separation column using an eluent, and the column chromatographically separates the ions to be measured in the sample. Afterwards, the ion O conductivity is detected by a detector (conductivity meter). Furthermore, in order to reduce the conductivity background of the eluent, a suppressor column filled with, for example, an anion exchange resin having a large exchange capacity is often installed between the separation column and the detector. When a nitric acid (HNO3) solution is used as the eluent, the anion exchange resin in the suppressor column changes from the OH'' type to the NO3- type over time. In the OH''' type, the nitric acid solution changes to water (20) by passing through the suppressor column, reducing the conductivity background of the eluent, but in the NO3- type, the nitric acid solution does not change to water. No decrease in the conductivity background of the eluent was observed.Therefore, in order to keep the anion exchange resin in the suppressor column in the OH-type, a regenerating solution such as sodium hydroxide (NaOH) was flowed through the suppressor column. A playback operation was being performed.

<Problems to be Solved by the Invention> However, in the above-mentioned conventional example, the above-mentioned regeneration operation is not performed after the suppressor column becomes unusable or the function of reducing the conductivity background deteriorates after being used for a certain period of time. I was trying to do it.

For this reason, the analysis has to be interrupted in order to carry out the regeneration operation, which has resulted in major drawbacks such as making it difficult to carry out continuous analysis over a long period of time. The present invention has been made in view of the drawbacks of the prior art, and its object is to provide a high performance liquid chromatograph in which a suppressor column can be regenerated without interrupting analysis.

<Means to Solve the Problems> A feature of the present invention that solves the above-mentioned problems is that in a high performance liquid chromatograph, a certain amount of sample is collected with a sampling valve and then a certain amount of sample is collected after a certain period of time. The regeneration liquid was introduced into the suppressor column.

<Example> Hereinafter, the present invention will be explained in detail using the drawings. 1st
The figure is an explanatory diagram of the configuration of an embodiment of the present invention. In the figure, la is a tank for storing an eluent made of, for example, 5 mN nitric acid (HNO3) solution, and lc is, for example, 0.0 mN. IN Sodium hydroxide (NaO
H) A tank for storing a regenerating liquid consisting of a solution, lb and ld are waste liquid tanks, 2a and 2b are liquid feeding pumps, 3 is, for example, the first to sixth connection ports 33 to 3f and an internal volume of 10θIJt't, for example.
- a sampling valve having a metering tube 3g and whose internal flow path is alternately switched between the solid line connection state and the broken line connection state in FIG. 1;
4 is a separation column filled with, for example, a cation exchange resin; 5 is equipped with, for example, first to sixth connection ports 5a to 5f and a metering tube 5g having an internal volume of 10 mA; A flow path switching valve is alternately switched to the connected state, 6 is a suppressor column filled with, for example, Hama ion exchange resin having an extremely large ion exchange capacity, 7 is a detector, for example, a conductivity meter, and 8 is a separation column 4. Suppressor column 6. and a constant temperature bath that houses the detector 7 and keeps them at a predetermined temperature (for example, 45° C.).

In the embodiment of the present invention having such a configuration, when the pump 2a is driven, the eluent in the tank la is, for example, 2
At a flow rate of ml/min, pump 2a→first and second connection ports 3a, 3b of sample collection valve 3→separation column 4→first and second connection ports 5a of flow path switching valve 5, sb→suppressor column 6 -> detector 7 and then guided to tank 1b. Moreover, when the pump 2b is driven as necessary,
The regenerating liquid in tank la is, for example, 1 ml/min.

With a flow rate of , pump 2b→fifth and sixth of sampling valve 3
It is led to the tank 1dK through the connection ports 5e and 5f → the metering pipe 5g → the third and fourth connecting ports 5ce 5d, and fills the inside of the metering pipe 5g. In such a situation, when a sample is injected from the fifth connection port 3e of the sample sampling valve 3 using, for example, a syringe, the sample flows through the sixth connection port 3f → measurement −g3g → third connection port 3cm+ It flows through the path of the fourth connecting hole 3d and fills the inside of the metering tube 3g. Thereafter, when the sampling valve 3 is turned on, its internal flow path is switched from the solid line connection state in FIG. 1 to the dashed line connection state. Therefore, the sample in the measuring tube 3g is carried by the eluent to the separation column 4, where the cations in the sample are chromatographically separated. The eluate from the column 4 passes through the suppressor column 6 to the detector 7.
conductivity is detected. Incidentally, as described above, the conductivity and the gradient of the eluent are reduced in the suppressor column 6, but if the eluent continues to flow, the function of the suppressor column 6 will deteriorate. Therefore, for example, when the flow path switching valve 5 is turned on 8.5 minutes after turning on the sample collection valve 3, the internal flow path of the switching valve 5 is switched from the solid line connection state in FIG. 1 to the broken line connection state. . Therefore, the regenerating liquid in the measuring tube 5g is carried into the suppressor column 6 and the anion exchange resin in the column 6 is regenerated. Therefore, by periodically introducing the regenerating liquid into the suppressor column 6 by turning on and off the flow path switching valve 5, the suppressor column 604' can be efficiently stabilized and the ground reduction function can be maintained stably for a long period of time. be able to maintain it.

FIG. 2 is a chromatogram drawn by guiding the output of the detector 7 to a recorder (not shown) in an embodiment of the present invention that performs the series of operations described above. In the figure, the horizontal axis is time T (the unit is Minutes) and the vertical axis is conductivity 0 (unit: IJs/am)
It shows. Moreover, the broken line indicates the fluctuation of the baseline due to the ON/OFF state of the flow path switching valve 5.

Note that the present invention is not limited to the above-described embodiments, and can be modified in various ways. For example, the following modifications may be made to analyze anions in a sample. It shall be permitted to do so. (b) The eluent in tank la is Na2003
/NaHOO3 mixed solution, (b) The regenerated liquid in the tank is a sulfuric acid (H2BO3) solution, ρ separation column 4
Fill the suppressor column 6 with an anion exchange resin. 2) Fill the suppressor column 6 with a cation exchange resin having a large exchange capacity.

<Effects of the Invention> According to the present invention as described in detail above, a high-performance liquid chromatograph is realized in which a suppressor column can be regenerated without interrupting analysis. If such a high-performance liquid chromatograph is used, there is no need to interrupt the analysis and perform special regeneration operations as in the conventional example, and there is no need to worry about deterioration of the function of the suppressor column. It has the advantage of being able to contribute greatly to continuous analysis, such as by being able to assemble data. Further, the amount of regenerating liquid introduced into the suppressor column 6 is determined by the metering pipe 5 of the flow path switching valve 5.
Since only the g-content integral is used, the baseline is stabilized quickly and the next analysis can be carried out in a short time.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the configuration of an embodiment of the present invention, and FIG. 2 is a chromatogram prepared using the embodiment of the present invention. 1a=1d...tank, 2a, 2b...pump, -3
... Sample collection valve, 4... Separation column, 5... Flow path switching valve, 6... Suppressor column, 7... Detector.

Claims (2)

[Claims] (1) A sample collection valve that collects a fixed amount of a sample containing ions to be measured, a separation column that chromatographically separates the ions to be measured in the sample, and a suppressor column that reduces the conductivity background of the eluent; comprising a detector that detects the conductivity of the liquid eluted from the suppressor column, and a flow path switching valve that is disposed between the separation column and the suppressor column and introduces a certain amount of regeneration liquid into the suppressor column, A high-performance liquid chromatograph, characterized in that the regeneration liquid is introduced into the suppressor column after a certain period of time after a certain amount of sample is collected by the sample sampling valve. (2) The high-speed liquid chromatograph according to claim (1), wherein the flow path switching valve is a six-way switching valve including first to sixth connection ports and a metering tube having a constant volume.