Chromatogram analyzer

Abstract

A chromatogram analyzer having a function for automatically excluding noise peaks from analysis targets is provided. [Solution] In a fluid chromatograph (100), a sample arrival time, which is the time required for a sample injected into a mobile phase to reach a detector (108), and a mobile phase arrival time, which is the time required for the mobile phase delivered from a liquid delivery device (102) to reach the detector (108), are calculated based on system information, which is the capacity of the piping, flow rate information related to the flow rate of the mobile phase, and composition information for each time period during analysis. A target range determination unit (8) determines these based on the mobile phase arrival time and the sample arrival time so that composition-related peaks, which are peaks caused by a sudden change in the composition of the mobile phase, and injection-related peaks, which are peaks caused by the injection of the sample, are excluded from the analysis target. The system is configured to perform peak analysis within the target range determined by the target range determination unit (8).

Description

[Technical Field]

[0001] The present invention relates to a chromatogram analyzer. [Background technology]

[0002] There are devices that perform analysis processing of chromatograms obtained by fluid chromatographs such as liquid chromatographs and supercritical fluid chromatographs (see Patent Document 1). Chromatogram analysis devices can not only detect peaks appearing in a chromatogram and calculate the area of ​​each peak, but also separate multiple peaks that overlap each other and estimate the shape and size of each peak. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-148776 Summary of the Invention [Problem to be solved by the invention]

[0004] In liquid chromatographs and supercritical fluid chromatographs, sudden changes in the mobile phase composition or sudden changes in pressure due to sample injection can be recorded as peaks on a chromatogram. However, if such noise peaks are recognized by an analytical instrument as peaks originating from components in the sample, the reliability of the analysis results will be compromised. For example, if the number of components contained in a sample is known, the number of peaks to be analyzed may be preset. However, if noise peaks are recognized as component peaks, component peaks that should be analyzed will be omitted from the analysis, resulting in the analysis not being performed. Therefore, before performing an analysis, users must remove noise peaks that are not originating from components. However, this process is cumbersome and makes it difficult to distinguish between component peaks and noise peaks.

[0005] The present invention has been made in view of the above problems, and has as its object to provide a chromatogram analyzer having a function of automatically excluding noise peaks from the analysis target. [Means for solving the problem]

[0006] The chromatogram analyzer according to the present invention comprises: a system information storage unit that stores a system capacity, which is the capacity of a pipe through which a sample of a fluid chromatograph passes; an analysis information storage unit that stores a chromatogram obtained by an analysis performed by the fluid chromatograph, flow rate information related to the flow rate of the mobile phase during the analysis, and composition information related to the composition of the mobile phase in each time period during the analysis; a time calculation unit configured to calculate a mobile phase arrival time, which is the time required for a mobile phase delivered from a liquid delivery device of the fluid chromatograph to reach a detector, and a sample arrival time, which is the time required for a sample injected into the mobile phase to reach the detector, based on the system capacity, the flow rate information, and the composition information; a target range determination unit configured to determine a target range of peak analysis on the chromatogram based on the mobile phase arrival time and the sample arrival time so that a composition-related peak, which is a peak caused by a sudden change in the composition of the mobile phase, and an injection-related peak, which is a peak caused by injection of a sample into the mobile phase, are excluded from the analysis target; and a peak analysis unit configured to perform the peak analysis within the target range determined by the target range determination unit. [Effects of the Invention]

[0007] The chromatogram analyzer according to the present invention is configured to calculate the mobile phase arrival time and sample arrival time based on the system capacity of the fluid chromatograph, mobile phase flow rate information, and composition information regarding the composition of the mobile phase in each time period, determine the analysis range based on the calculated mobile phase arrival time and sample arrival time so that composition-related peaks and injection-related peaks, which are noise peaks, are excluded from the analysis target, and perform peak analysis within the determined analysis range, thereby enabling noise peaks to be automatically excluded from the analysis target. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram illustrating an embodiment of a chromatogram analyzer. [Figure 2] FIG. 1 shows an example of the procedure for determining the analysis range in this example. The upper figure is a chromatogram obtained by analyzing a certain sample, and the lower figure is a graph showing the composition of the mobile phase (concentration of solution B) at each time point during the same analysis. [Figure 3] 4 is a flowchart illustrating an example of the operation of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the chromatogram analyzer will be described below with reference to the drawings.

[0010] As shown in FIG. 1, the chromatogram analysis device 1 is a device that analyzes a chromatogram obtained by analyzing a sample using a fluid chromatograph 100, and is realized by a computer device (e.g., a personal computer) on which an analysis program is installed.

[0011] The fluid chromatograph 100 is a liquid chromatograph and includes a liquid delivery device 102, an autosampler 104, a separation column 106, a detector 108, and a controller 110. The liquid delivery device 102 delivers two types of liquid, liquid A and liquid B, to a mixer, mixes them, and delivers the mixed liquid as a mobile phase. The autosampler 104 is fluidically connected downstream of the liquid delivery device 102 and injects a sample into the mobile phase delivered from the liquid delivery device 102. The separation column 106 is fluidically connected downstream of the autosampler 104 and separates multiple components in the sample injected into the mobile phase by the autosampler 104. The detector 108 is fluidically connected downstream of the separation column 106 and outputs a signal with an intensity corresponding to the concentration of each component separated by the separation column 106. The controller 110 controls the operation of at least the liquid delivery device 102 and the autosampler 104. The signal output from the detector 108 is input to the chromatogram analyzer 1 through the controller 110 .

[0012] Although the fluid chromatograph 100 used to obtain a chromatogram of a sample is a liquid chromatograph, it may also be a supercritical fluid chromatograph or an ion chromatograph.

[0013] The chromatogram analyzer 1 comprises a system information storage unit 2, an analytical information storage unit 4, a time calculation unit 6, a target range determination unit 8, and a peak analysis unit 10. The system information storage unit 2 and the analytical information storage unit 4 are each functions realized by a partial storage area of ​​an information storage device such as a hard disk drive or flash memory. The time calculation unit 6, the target range determination unit 8, and the peak analysis unit 10 are functions realized by a CPU (central processing unit) executing a predetermined program.

[0014] The system information storage unit 2 stores system information including the system capacity of the fluid chromatograph 100. The system capacity can include the capacity from the mixer of the liquid delivery device 102 to the autosampler 104, the capacity of the flow path in the autosampler 104, the capacity from the autosampler 104 to the separation column 106, the capacity within the separation column 106, and the capacity from the separation column 106 to the detector 108.

[0015] The analytical information memory unit 4 stores the chromatogram obtained in the analysis performed by the fluid chromatograph 100, the flow rate information of the mobile phase during the analysis, and the composition information of the mobile phase at each time during the analysis (e.g., gradient program).

[0016] The time calculation unit 6 is configured to calculate the sample arrival time T1, which is the time required for the sample to reach the detector 108 without being captured by the separation column 106, and the mobile phase arrival time T2, which is the time required for the mobile phase delivered from the liquid delivery device 102 to reach the detector 108, using the system information stored in the system information storage unit 2 and the flow rate information and composition information stored in the analysis information storage unit.

[0017] The sample arrival time T1 can be calculated by dividing the internal volume from the autosampler 104 to the detector 108 by the flow rate of the mobile phase. The mobile phase arrival time T2 can be calculated by dividing the internal volume from the liquid delivery device 102 to the detector 108 by the flow rate of the mobile phase.

[0018] The target range determination unit 8 is configured to determine an analysis target range on the chromatogram based on the sample arrival time T1 and the mobile phase arrival time T2 calculated by the time calculation unit 6. The analysis target range is determined so that injection-related peaks, which are peaks that may appear due to sample injection, and composition-related peaks, which are peaks that may appear due to a sudden change in the composition of the mobile phase, are not included in the analysis target.

[0019] The peak analysis unit 10 is configured to perform peak analysis of the chromatogram within the analysis target range determined by the target range determination unit 8.

[0020] The procedure for determining the analysis range will be explained using FIG.

[0021] An injection-induced peak resulting from sample injection can appear near t0 + T1, which is the time when the solvent injected with the sample reaches the detector. This is defined as the time when the sample is injected, i.e., t0 plus the sample arrival time T1. However, as shown in Figure 2, injection-induced peaks can have a negative intensity portion in the first half of the peak. Therefore, if a peak appears near t0 + T1, it can be determined whether or not it is an injection-induced peak based on whether or not the peak has a negative intensity portion. If a peak with a negative intensity portion appears near t0 + T1 on the chromatogram, the start time of the analysis range can be set to t0 + T1 + α to exclude this peak from the analysis. α is set with a sufficient margin to prevent the injection-induced peak from being included in the analysis.

[0022] On the other hand, if a peak appears on the chromatogram near time t0+T1 but does not have a negative intensity portion, this peak is considered to be a peak derived from a component that the separation column 106 does not have the retention power to (that elutes from the separation column 106 together with the solvent), and therefore the analysis range is set to include this peak in the analysis target. In this case, for example, the start point of the analysis range can be set to t0+T1-α.

[0023] Furthermore, if the time when the composition of the mobile phase delivered by the liquid delivery device 102 is suddenly changed is t1, a composition-related peak resulting from a sudden change in the composition of the mobile phase may appear at a position near t1+T2, which is calculated by adding t1 to the mobile phase arrival time T2 required for the mobile phase whose composition has suddenly changed to reach the detector 108 from the liquid delivery device 102. Therefore, the end time of the analysis range can be set to t1+T2-β so as to exclude the composition-related peak from the analysis target. β is a value set with a sufficient margin in mind so that the composition-related peak is not included in the analysis target. β may be the same as or different from α.

[0024] Examples of timings for sudden changes in the mobile phase composition include, as shown in the example of Figure 2, when the concentration of solution B in the mobile phase is gradually increased after the sample is injected and analysis begins, and then the concentration of solution B is returned to the equilibrium concentration (0%) after a certain time has passed since the concentration of solution B reached 100% (after gradient flow is completed), and also when the concentration of solution B in the mobile phase is gradually increased until it reaches the final concentration (e.g., 80%), which is the final concentration of the gradient increase, and then the concentration of solution B is raised to the wash concentration (100%). The timing for sudden changes in the mobile phase composition can be determined, for example, from the gradient program set for each analysis.

[0025] Next, the procedure for analyzing peaks in a chromatogram by the chromatogram analyzer 1 will be described with reference to the flowchart of FIG. 3 as well as FIG.

[0026] When the user selects a chromatogram for which peak analysis is to be performed and inputs an instruction to start the analysis, the time calculation unit 6 calculates the sample arrival time and the mobile phase arrival time based on the information stored in the system information storage unit 2 and the analysis information storage unit 4, respectively (step 101).

[0027] Next, the target range determination unit 8 determines the analysis target range using the sample arrival time and mobile phase arrival time calculated by the time calculation unit 6 so that the injection-related peak and composition-related peak are excluded from the analysis target (step 102).

[0028] Once the analysis range is determined, the peak analysis unit 10 performs peak analysis within the determined analysis range (step 103). The chromatogram analysis device 1 outputs the analysis data obtained by the peak analysis by the peak analysis unit 10 to the display 12 for display.

[0029] The above-described embodiment is merely one example of the embodiment of the chromatogram analyzer according to the present invention. The embodiment of the chromatogram analyzer according to the present invention is as follows.

[0030] One embodiment of the chromatogram analyzer according to the present invention comprises: a system information storage unit that stores a system capacity, which is the capacity of a pipe through which a sample of a fluid chromatograph passes; an analysis information storage unit that stores a chromatogram obtained by an analysis performed by the fluid chromatograph, flow rate information related to the flow rate of the mobile phase during the analysis, and composition information related to the composition of the mobile phase in each time period during the analysis; a time calculation unit configured to calculate a mobile phase arrival time, which is the time required for a mobile phase delivered from a liquid delivery device of the fluid chromatograph to reach a detector, and a sample arrival time, which is the time required for a sample injected into the mobile phase to reach the detector, based on the system capacity, the flow rate information, and the composition information; a target range determination unit configured to determine a target range of peak analysis on the chromatogram based on the mobile phase arrival time and the sample arrival time so that a composition-related peak, which is a peak caused by a sudden change in the composition of the mobile phase, and an injection-related peak, which is a peak caused by injection of a sample into the mobile phase, are excluded from the analysis target; and a peak analysis unit configured to perform the peak analysis within the target range determined by the target range determination unit.

[0031] In a first aspect of the above embodiment, the target range determination unit is configured to set the start time of the target range to a time that is a certain amount of time after the sample arrival time has elapsed since the sample was injected into the mobile phase when a peak having a negative intensity portion appears in the chromatogram at a position near the time when the sample arrival time has elapsed since the sample was injected into the mobile phase.

[0032] In the first aspect, the target range determination unit can be configured to set the start time of the target range to a time that is a certain amount of time before the sample arrival time has elapsed since the sample was injected into the mobile phase when a peak without a negative intensity portion appears in the chromatogram at a position near the time when the sample arrival time has elapsed since the sample was injected into the mobile phase.

[0033] In a second aspect of the above embodiment, the target range determination unit is configured to set the end time of the target range to a time after gradient flow of the mobile phase in the chromatogram is completed, the time being a certain time before the time at which the mobile phase arrival time has elapsed since the time at which the mobile phase composition suddenly changed. This second aspect can be combined with the first aspect.

[0034] In a third aspect of the above embodiment, the composition information is a preset gradient program of the mobile phase. This third aspect can be combined with the first aspect and / or the second aspect.

[0035] In a fourth aspect of the above embodiment, the system volume includes a first system volume that is a volume from an autosampler that injects a sample to a detector, and a second system volume that is a volume from a liquid delivery device that delivers a mobile phase to the detector. This fourth aspect can be combined with the first aspect, the second aspect, and / or the third aspect. [Explanation of symbols]

[0036] 1. Chromatogram analyzer 2 System information storage section 4 Analysis information storage section 6 Time calculation section 8. Target Scope Determination Department 10 Peak analysis section 12 Display 100 Fluid Chromatograph 102 Liquid delivery device 104 Autosampler 106 Separation Column 108 detectors 110 Controller

Claims

1. a system information storage unit that stores a system capacity, which is the capacity of a pipe through which a sample of a fluid chromatograph passes; an analysis information storage unit that stores a chromatogram obtained by an analysis performed by the fluid chromatograph, flow rate information related to the flow rate of the mobile phase during the analysis, and composition information related to the composition of the mobile phase in each time period during the analysis; a time calculation unit configured to calculate a mobile phase arrival time, which is the time required for a mobile phase delivered from a liquid delivery device of the fluid chromatograph to reach a detector, and a sample arrival time, which is the time required for a sample injected into the mobile phase to reach the detector, based on the system capacity, the flow rate information, and the composition information; a target range determination unit configured to determine a target range of peak analysis on the chromatogram based on the mobile phase arrival time and the sample arrival time so that a composition-related peak, which is a peak caused by a sudden change in the composition of the mobile phase, and an injection-related peak, which is a peak caused by injection of a sample into the mobile phase, are excluded from the analysis target; a peak analysis unit configured to perform the peak analysis within the target range determined by the target range determination unit.

2. 2. The chromatogram analysis apparatus according to claim 1, wherein the target range determination unit is configured to set the start time of the target range to a time that is a certain amount of time after the sample arrival time has elapsed since the sample was injected into the mobile phase when a peak having a negative intensity portion appears in the chromatogram near the time when the sample arrival time has elapsed since the sample was injected into the mobile phase.

3. 3. The chromatogram analysis apparatus according to claim 2, wherein the target range determination unit is configured to set the start time of the target range to a time that is a certain amount of time before the sample arrival time has elapsed since the sample was injected into the mobile phase when a peak without a negative intensity portion appears in the chromatogram near the time when the sample arrival time has elapsed since the sample was injected into the mobile phase.

4. The chromatogram analysis device according to claim 1, wherein the target range determination unit is configured to set the end time of the target range to a time after gradient flow of the mobile phase in the chromatogram has ended, the time being a certain time before the time at which the mobile phase arrival time has elapsed since the time at which the composition of the mobile phase suddenly changed.

5. The chromatogram analyzer according to claim 1 , wherein the composition information is a preset gradient program for the mobile phase.

6. The chromatogram analyzer according to claim 1, wherein the system capacity includes a first system capacity which is the capacity from an autosampler that injects a sample to a detector, and a second system capacity which is the capacity from a liquid delivery device that delivers a mobile phase to the detector.

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