JPH0593718A - Process liquid chromatograph - Google Patents

Abstract

PURPOSE:To measure numerous kinds of samples and, at the same time, to improve the measurement accuracy and sensitivity of a process liquid chromatograph. CONSTITUTION:A mixer 14 is connected to a dilution valve 10 provided with a measuring loop 12 and an injector 20 is connected to the exit of the mixer 14. A measuring loop 22, column 24, and eluate pump 30 are connected to the injector 20 and a dilution liquid concentration detector 44 is provided to a waste water flowing passage 21. A peak position detecting/controlling device 46 detects the peak position of the concentration of a dilution liquid from the detecting signal of the detector 44 and switches the injector 20 to the sampling side (broken line side) at the peak time of the detected peak position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process liquid chromatograph which is connected to a process line of the chemical industry and can sample and analyze samples online from the process side.

[0002]

2. Description of the Related Art If a process liquid chromatograph is to be realized, it is suitable for analyzing a sample by a liquid chromatograph as a sample introducing section for collecting a sample from the process side and introducing it into the liquid chromatograph. It is necessary to provide a diluter for diluting to a concentration range where a linear relationship between the concentration and the detected value is obtained. As such a diluting device, it is considered to have a mixer, which sends a sample from a sample pump to the mixer, sends a diluting liquid from a diluting liquid pump, mixes and dilutes the sample with a mixer, and injects it into a liquid chromatograph. Be done.

[0003]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention In a diluting device in which a sample and a diluting liquid are pumped to a mixer and mixed, a large pump is required for the diluting liquid pump, and the diluting liquid consumes a large amount. Therefore, as shown in FIG. 1, a process liquid chromatograph provided with a diluting device for guiding the sample collected by the measuring loop 12 to the mixer 14 and diluting it has been proposed. In FIG. 1, 2 is a reactor of a process line, and a circulation flow path including a pump 4 and a cross flow type ceramic filter 6 is connected to the process line 2. A diluting valve 10, which is a six-way valve, is connected to the filtrate outlet of the filter 6 via a sample pump 8. The dilution valve 10 is provided with a metering loop 12, a mixer 14 for diluting a sample is connected to the dilution valve 10, a diluent pump 18 for supplying a diluent 16 is connected, and a drain passage to a drain 19 is also connected. ing. The outlet of the mixer 14 is connected to an injector 20 of a high performance liquid chromatograph (HPLC). The injector 20 is of a six-way switching valve type and has a metering loop 22. The sample supplied from the mixer 14 to the injector 20 and not injected into the column 24 is discharged to the drain 26. An eluent pump 30 for supplying an eluent 28 to the HPLC and a column 24 are connected to the injector 20. 32 is a detector and 34 is a data processing device.

In order to sample the sample diluted by the mixer 14 of the diluting device with the injector 20 and introduce it into the column 24, the injector 20 causes the sample to flow from the metering loop 22 to the drain 26 in accordance with a solid flow path.
When the time for the sample to pass through the metering loop 22 is observed, the injector is switched to the flow path indicated by the broken line, and the eluent 28 delivers the sample to the column 24. When the switching of the flow path in the injector 20 is controlled by the time, the dilution liquid concentration is shown in FIG.
As shown in (B), A, A
It changes like B and C, and the residence time T until the peak of the diluent concentration appears. Therefore, it is difficult to obtain sufficient accuracy and sensitivity when performing measurement by switching many kinds of samples. Then, this invention makes it possible to measure many kinds of samples, and further aims to improve the measurement accuracy and sensitivity.

[0005]

According to the present invention, a diluent concentration detector is provided in a drainage channel of an injector of a liquid chromatograph, and a peak position of the diluent concentration is detected from a detection signal of the diluent concentration detector. , A peak position detection control device for switching the injector to the sampling side at the peak time.

[0006]

If the injectors are switched at the peak position of the diluent concentration instead of being changed over time, the diluent concentration is sampled at the peak position even if the residence time T shown in FIG. 2 (A) changes. Therefore, accuracy and sensitivity are improved.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 3 shows a first embodiment. The same symbols are used for the same parts as in FIG. From the process side, three types of samples A, B and C can be introduced to the dilution valve 10 via the sample pump 8 by switching the sample switching valves 40a to 40c. The dilution valve 10 is a six-way valve, is equipped with a metering loop 12 having a volume of 20 μl, and has a diluent pump 18
, Three kinds of diluents a to c are selected and supplied by the diluent switching valves 42a to 42c. A mixer 14 is connected to the dilution valve 10, and an injector 20 is connected to the outlet of the mixer 14. The injector 20 includes a metering loop 22 having a volume of 20 μl, a column 24 is connected to the injector 20, and an eluent is supplied by an eluent pump 30. The injector 20 is further provided with a diluent concentration detector 44 in the drainage passage 21. Reference numeral 46 is a peak position detection control device that detects the peak position of the diluent concentration from the detection signal of the diluent concentration detector 44 and switches the injector 20 to the sampling side (broken line side) at the peak time.

The flow path of the column outlet is guided to the detector 32,
The detection signal of the detector 32 is processed by the data processor 34. A sequence controller 48 controls the switching of the sample switching valves 40a to 40c, the diluting liquid switching valves 42a to 42c, and the dilution valve 10, and the data processing device 3
It also controls the operation of 4.

Next, in this embodiment, the sample A is diluted with the diluent a.
An example will be described in which measurement is performed by diluting with. The sequence controller 48 sets the dilution valve 10 to the flow path indicated by the solid line, the sample switching valve 40a and the diluting liquid switching valve 42a are opened, and the sample A is diluted by the sample pump 8 and the diluting liquid a is diluted by the diluting liquid pump 18. Flowed through the solid flow path of valve 10. When the flow path of the dilution valve 10 is switched to the position of the broken line by the sequence controller 48, the metering loop 12
20 μl of the sample A is weighed, then the flow path is switched to the position indicated by the solid line, and the sample A in the weighing loop 12 is sent to the mixer 14 by the diluent a from the diluent pump 18 and diluted. The injector 20 is initially set at the position indicated by the solid line, and the sample solution sent from the mixer 14 is discharged through the diluent concentration detector 44. When the diluent concentration is detected by the detector 44 and the peak position detection controller 46 detects the peak position of the diluent concentration from the change over time, the injector 20 is switched to the flow path indicated by the broken line and is sent from the eluent pump 30. As the eluent, 20 μl of the sample A solution in the measuring loop 22 is sent to the column 24. The sample is separated in the column 24, converted by the electric signal in the detector 32, and displayed and recorded as a chromatogram by the data processor 34. For the other samples B and C, the respective switching valves are opened and measured in the same manner.

Although the diluent concentration detector 44 is provided separately from the detector 32 in the embodiment shown in FIG. 3, the detector 32 can also be used as a diluent concentration detector. Such an embodiment is shown in FIG. In FIG. 4, a detector switching four-way valve 50 is provided to guide the injector drainage flow passage 21 to the detector 32, instead of providing the diluent concentration detector 44 specific to the injector drainage flow passage 21. Switch to discharge to the drain. That is, when the drainage flow path 21 is connected to the detector 32, the flow path from the column 24 is connected to the drain side, and when the flow path 24 from the column 24 is connected to the detector 32, the drainage flow path. 21 is connected to the drain side. The peak position detector 46 is connected to receive the detection signal of the detector 32.

When diluting the sample with the mixer 14 and flowing it into the injector 20, the flow path of the four-way valve 50 is set to the position of the broken line, and the concentration of the diluting liquid is detected by the detector 32. When detected by the detector 32, the peak position detection controller 46 switches the flow path of the injector 20 to send the sample in the measuring loop 22 to the column with the eluent, and the four-way valve 50 and the column 24 are connected to the detector 32. Switch to the solid line side. Therefore, in this case, the peak position detector 46 is connected to receive the detection signal of the detector 32. The configuration of FIG. 4 requires only one detector, and the cost of the device can be reduced.

[0012]

According to the present invention, since the injectors are switched at the peak position of the concentration of the eluent, the accuracy and sensitivity are improved, and the injectors can be switched under a constant condition even when the sample or the diluent is changed. Therefore, it is possible to measure many kinds of samples with one device. Moreover, since a large number of types of samples can be measured in this way, the economical efficiency of the apparatus is improved. In the diluter, the mixer and piping change due to use, and the residence time of the diluent changes.Therefore, if the injectors are switched based on time, the allowable range of changes in the residence time is In contrast to the small setting and low durability of the diluting device, according to the present invention, the injector is switched at the diluting liquid peak even when the residence time changes significantly, so that the allowable range becomes large, and as a result, the durability of the diluting device is increased. Is improved.

[Brief description of drawings]

FIG. 1 is a flow diagram showing a process liquid chromatograph under consideration.

FIG. 2 is a diagram showing a change with time of the concentration of a diluting solution,
Is a diagram showing general changes, and (B) is a diagram showing fluctuations in peak positions.

FIG. 3 is a flow chart showing an example.

FIG. 4 is a flow chart showing a detector portion in another embodiment.

[Explanation of symbols]

 10 Diluting Valve 12 Metering Loop 14 Mixer 18 Diluting Liquid Pump 20 Injector 21 Waste Liquid Flow Path 22 Measuring Loop 24 Column 30 Diluting Liquid Pump 32 Detector 44 Diluting Liquid Concentration Detector 46 Peak Position Detection Controller

Claims (1)

[Claims] 1. A liquid chromatograph as an analysis unit,
It is equipped with a sample introduction part that collects and dilutes a sample from the process side and introduces it to the analysis part.The sample introduction part is connected to the process side and a dilution valve that collects the sample in the measuring loop, and mixes the sample and the diluent. A diluent and a diluent pump for sending the diluent to the mixer through the dilution valve are provided, and a diluent concentration detecting device is provided in the drainage flow path of the injector of the liquid chromatograph, and the diluent is detected from the detection signal of the diluent concentration detecting device. A process liquid chromatograph equipped with a peak position detection controller that detects the peak position of the concentration and switches the injector to the sampling side during the peak time.