EP-4270000-B1 - LIQUID CHROMATOGRAPH CONTROL METHOD AND LIQUID CHROMATOGRAPH

Inventors

• ITO, SHINYA

Dates

Publication Date

20260506

Application Date

20211207

Claims (4)

1. A method of controlling a liquid chromatograph (1) comprising: a pump (12) having a gradient function capable of feeding liquid while changing composition of a plurality of eluents, according to gradient liquid feeding conditions; a sample filling unit (14) for filling a sample; a separation column (15); an analysis flow channel (20) which connects the pump (12) to the separation column (15) passing through the sample filling unit (14); and a pressure sensor (13) which detects a pressure within the analysis flow channel (20) during liquid feeding by the pump (12), wherein when a maximum pressure presumed (P max ) is determined to be a predetermined upper limit of pressure (P limit ) and more, the sample filling is not performed, characterised in that an initial pressure (P ini ) of the analysis flow channel (20) is acquired from the pressure sensor (13) at the time of liquid feeding start in a state in which liquid feeding from the pump (12) is in a steady state so that a constant pressure value can be detected, and the maximum pressure presumed (P max ) during measurement is calculated based on the initial pressure (P ini ) and the gradient liquid feeding conditions.
2. The method of controlling the liquid chromatograph (1) according to claim 1, further comprising: two or more analysis flow channels (20) each including the liquid feeding pump (12), the sample filling unit (14), and the separation column (15); and one or more detectors (16) arranged downstream of the analysis flow channels (20), wherein when the maximum pressure presumed (P max ) in one of the analysis flow channels (20) is determined to be the upper limit (P limit ) of pressure and more, the sample filling is performed in another one of the analysis flow channels (20).
3. A liquid chromatograph (1) comprising: a pump (12) having a gradient function capable of feeding liquid while changing composition of a plurality of eluents, according to gradient liquid feeding conditions; a sample filling unit (14) for filling a sample; a separation column (15); an analysis flow channel (20) which connects the pump (12) to the separation column (15) passing through the sample filling unit (14); a pressure sensor (13) which detects a pressure within the analysis flow channel (20) during liquid feeding by the pump (12); and a control unit (17), wherein the control unit (17) controls the sample filling unit (14) not to perform the sample filling when a maximum pressure presumed (P max ) is determined to be a predetermined upper limit of pressure (P limit ) and more, characterised in that the control unit (17) acquires from the pressure sensor (13) an initial pressure (P ini ) of the analysis flow channel (20) at the time of liquid feeding start in a state in which liquid feeding from the pump (12) is in a steady state so that a constant pressure value can be detected, and calculates the maximum pressure presumed (P max ) during measurement, based on the initial pressure (P ini ) and the gradient liquid feeding conditions.
4. The liquid chromatograph (1) according to claim 3, further comprising: two or more analysis flow channels (20) each including the liquid feeding pump (12), the sample filling unit (14), and the separation column (15); and one or more detectors (16) arranged downstream of the analysis flow channels (20), wherein when the maximum pressure presumed (P max ) in one of the analysis flow channels (20) is determined to be an upper limit of pressure (P limit ) and more, the sample filling unit (14) is controlled to perform the sample filling in another one of the analysis flow channels (20).

Description

Technical Field The present invention relates to a method of controlling a liquid chromatograph and a liquid chromatograph. Background Art Separation columns of liquid chromatographs cannot be used above a predetermined pressure. The pressure in the flow channel fluctuates due to gradient during the measurement, and thus the separation column is required to be used considering the maximum pressure reached in the fluctuation. PTL 1 relates to a technique for controlling the operation of a pump that feeds a liquid to a column of a liquid chromatograph. The literature discloses a technique "Provided is a method for controlling a liquid chromatography system including a system pump and a column in fluid communication with the system pump by a fluid flow channel. The method includes: a step of recording the system pressure at a flow channel position close to the system pump, a step of controlling the operation of the system pump in response to the recorded system pressure, a step of estimating a pre-column pressure based on the recorded system pressure, the characteristics of the flow channel, and the viscosity and flow rate of the liquid in the system, and a step of controlling the operation of the system pump in response to the estimated pre-column pressure" (see Abstract). Citation List Patent Literature PTL 1: JP2015-526731A Summary of Invention Technical Problem In the method of controlling a liquid chromatograph in the related art as in PTL 1, the sample is actually measured, that is, the liquid is actually fed to the separation column, the system pressure is monitored, and the pressure fluctuation (time change) in the flow channel is measured. However, if the maximum pressure reached exceeds the upper limit during measurement, the measurement is stopped at that point. Meanwhile, it is difficult to obtain the maximum pressure reached before actual measurement (liquid feeding) by calculation. This is because many liquid chromatographs can use general-purpose columns and various mobile phases, and parameters of the tubing that configure the flow channel (the diameter and the length of a column) and fluid parameters (viscosity and mixing ratio of the mobile phase) are indeterminate. Therefore, the maximum pressure reached of the column portion is predicted based on the experience of an operator. As the separation column deteriorates, the initial pressure of the separation column increases. An increase in the initial pressure of the separation column makes it more difficult to predict the maximum pressure reached during the measurement. The invention has been conceived in view of the technical problems as described above and an object of the invention is to provide a method of controlling a liquid chromatograph and a liquid chromatograph that estimate the maximum value of the pressure reached of the pressure during measurement before actually performing the measurement. Solution to Problem To achieve the object the configurations described in the claims are adopted. The two-part form of present independent claims 1 and 3 is based on the liquid chromatograph disclosed in DE 10 2017 126893 A1. Advantageous Effects of Invention According to the invention, a method of controlling a liquid chromatograph and a liquid chromatograph which estimate the maximum value of the pressure reached during measurement before actually performing the measurement can be provided. Problems, configurations, and effects other than those described above become clear from the description of the following embodiments. Brief Description of Drawings [Fig. 1] Fig. 1 is a constitutional view of a liquid chromatograph 1 according to a first embodiment.[Fig. 2] Fig. 2 is an example of parameters of eluent mixed after gradient liquid feeding.[Fig. 3] Fig. 3 is a flow chart for deciding the propriety of measurement using an analysis flow channel 20 according to the first embodiment.[Fig. 4] Fig. 4 is a graph concerned about comparison S107 between the maximum pressure presumed Pmax and the upper limit of pressure Plimit.[Fig. 5] Fig. 5 is a constitutional view of a liquid chromatograph 1 according to a second embodiment.[Fig. 6] Fig. 6 is a flow chart for deciding the propriety of measurement using an analysis flow channel 20 according to the second embodiment. Description of Embodiments <First Embodiment: Apparatus Configuration> Hereinafter, an embodiment of the invention is described with reference to the drawings. FIG. 1 is a constitutional view of a liquid chromatograph 1 according to a first embodiment of the invention. The liquid chromatograph 1 is apparatus that separates a sample filled by a sample filling unit 14 by a stationary phase in a separation column 15 and an eluent supplied from an eluent bottle 11 (mobile phase) and detects the sample by a detector 16 installed downstream of the separation column 15. The liquid chromatograph 1 includes the eluent bottle 11, a pump 12, a pressure sensor 13, the sample filling unit 14, the sepa