Data Processing System

Abstract

To allow a user to easily recognize whether each peak part on a chromatogram is a coelution peak.SOLUTION: In a data processing system (1) for a chromatograph mass spectrometer (100), a data processing unit (10) is configured to create a chromatograph on the basis of measurement data, and specify, of peak parts on the chromatograph, a peak part in which peaks of a plurality of components overlap to form one peak shape as a coelution peak, by using a correspondence relationship between the chromatograph and mass spectrometry data. An information display unit (12) is configured to, when displaying the chromatograph, display the peak part specified by the data processing unit as the coelution peak in a mode different from that for other peak parts, and thereby allow a user to visually recognize whether each peak part on the chromatograph is the coelution peak.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a data processing system that performs data processing using analysis data obtained by a chromatograph mass spectrometer.

Background Art

[0002] In chromatographs such as liquid chromatographs and gas chromatographs, in order to develop an analysis method (a combination of conditions such as the separation column to be used, the mobile phase, and the flow rate of the mobile phase) that is optimal for analyzing a target sample, various analysis methods are used to perform analysis multiple times, and the analysis data obtained in each analysis is compared to search for an analysis method in which the components in the target sample are most effectively separated.

[0003] Depending on the analysis method, so-called co-elution may occur, in which a plurality of components in the sample are eluted from the separation column in a state where they are not completely separated from each other. When co-elution occurs, the peaks of the plurality of components overlap on the chromatogram to form a single peak shape (hereinafter referred to as a co-elution peak). Therefore, it is necessary to evaluate the experimental data obtained by the analysis using each analysis method while confirming whether the portion forming the peak shape on the chromatogram (hereinafter referred to as the peak portion) is a co-elution peak.

[0004] Here, in Patent Document 1, using the analysis data of a chromatograph mass spectrometer provided with a detector other than a mass spectrometer such as a PDA (photodiode array) detector and a mass spectrometer downstream of a separation column, information obtained from mass spectrometry data is added to the chromatogram obtained from the measurement data of the detector. According to the disclosed technique, information such as what components having what mass-to-charge ratio are eluting can be added to the chromatogram, so that the user can confirm whether each peak on the chromatogram is a co-elution peak by referring to the added information.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] International Publication No. 2020 / 194582 [Overview of the project] [Problems that the invention aims to solve]

[0006] In method development, it is necessary to select a method that provides good separation by referring to numerous chromatograms obtained from the same sample. Even if additional information extracted from mass spectrometry data is added to the chromatogram, the user must refer to this additional information to determine whether each peak in each chromatogram is a co-elution peak. Therefore, it is not easy for the user to visually recognize which chromatogram shows good separation.

[0007] This invention has been made in view of the above problems, and aims to enable users to easily recognize whether or not each peak portion on a chromatogram is co-eluting. [Means for solving the problem]

[0008] The data processing system according to the present invention comprises: a data holding unit that holds mass analysis data acquired by a mass spectrometer and measurement data acquired by a detector other than a mass spectrometer as analysis data by analyzing a sample using a chromatograph-mass spectrometer; a data processing unit configured to perform data processing using the analysis data held in the data holding unit; and an information display unit configured to display the data processed by the data processing unit, wherein the data processing unit is configured to create a chromatogram based on the measurement data, and to identify as a co-elution peak a peak portion on the chromatogram where the peaks of multiple components overlap to form a single peak shape using the correspondence between the chromatogram and the mass analysis data; and the information display unit is configured to display the peak portion identified as the co-elution peak by the data processing unit in a different manner from other peak portions when displaying the chromatogram, thereby allowing the user to visually recognize whether each peak portion on the chromatogram is the co-elution peak or not. [Effects of the Invention]

[0009] According to the data processing system of the present invention, co-elution peaks are identified using a chromatogram based on measurement data acquired by a detector and mass spectrometry data acquired by a mass spectrometer. When displaying the chromatogram, the peak portion identified as a co-elution peak is displayed in a manner different from other peak portions, allowing the user to visually recognize whether each peak portion is a co-elution peak or not. Thus, the user can easily recognize whether each peak on the chromatogram is a co-elution peak or not. [Brief explanation of the drawing]

[0010] [Figure 1] Block diagram showing one example of a data processing system. [Figure 2] This flowchart shows an example of the operation when displaying a chromatogram in the same embodiment. [Figure 3] This flowchart shows an example of how the system behaves when a peak is specified on a chromatogram. [Figure 4] This is an example of a chromatogram displayed on a screen. [Figure 5] This is an example of a screen showing when a co-elution peak is specified on the chromatogram. [Figure 6] This is an example of a screen displaying a peak table. [Modes for carrying out the invention]

[0011] Hereinafter, an embodiment of the data processing system according to the present invention will be described with reference to the drawings.

[0012] As shown in Figure 1, the data processing system 1 comprises a data processing unit 2, an input device 4, and a display 6. The data processing unit 2 is implemented by a computer device such as a personal computer with a dedicated program installed. The input device 4 is implemented by a keyboard and / or mouse, etc., which is connected to the data processing unit 2 in a communicative manner. The user can input information to the data processing unit 2 via the input device 4. The display 6 is connected to the data processing unit 2 in a communicative manner and displays the information output from the data processing unit 2.

[0013] The data processing device 2 comprises a data holding unit 8, a data processing unit 10, and an information display unit 12. The data processing device 2 receives analytical data acquired by analyzing a sample with a liquid chromatograph mass spectrometer 100 (hereinafter referred to as LC-MS100), and the acquired analytical data is stored in the data holding unit 8.

[0014] The LC-MS100 comprises a detector other than a mass spectrometer (e.g., a UV detector) located downstream of the separation column, and a mass spectrometer located downstream of that detector. The detector in the LC-MS100 provides measurement data showing the relationship between the elution time (retention time) from the separation column and the signal intensity corresponding to the component concentration in the eluate from the separation column. The mass spectrometer in the LC-MS100 provides scan data at regular intervals showing the relationship between the mass electrification ratio (m / z) of the components in the eluate after passing through the detector and the signal intensity corresponding to the amount of the components, which is obtained as mass analysis data. The data storage unit 8 stores the measurement data acquired by the detector and the mass analysis data acquired by the mass spectrometer. The data storage unit 8 is realized by a portion of the storage area of ​​the data storage device provided in the data processing device 2.

[0015] The data processing unit 10 is configured to perform data processing on the analysis data held in the data holding unit 8. Details of the data processing performed by the data processing unit 10 will be described later. The data processing unit 10 is a function obtained by the CPU (Central Processing Unit) of the data processing device 2 executing a program.

[0016] The information display unit 12 is configured to display data processed by the data processing unit 10 on the display 6. The information display unit 12 is also a function obtained by the CPU in the data processing unit 2 executing a program.

[0017] When displaying a chromatogram created based on measurement data obtained by the detector of the LC-MS100 on the display 6, the data processing system 1 of this embodiment shows the peak portions (portions where the waveform has a peak shape) appearing in the chromatogram that are co-elution peaks in a different manner from other peak portions so that the user can visually recognize whether or not the peak portions are co-elution peaks. A co-elution peak is a peak portion where peaks of a plurality of components overlap each other to form one peak shape. Whether or not each peak portion on the chromatogram is a co-elution peak can be determined, for example, using the method disclosed in International Publication No. 2020 / 194582.

[0018] An example of the data processing operation regarding the display of the chromatogram will be described below with reference to the flowchart of FIG. 2.

[0019] First, the data processing unit 10 reads in the target analysis data (step 101). The data processing unit 10 creates a chromatogram using the measurement data obtained by the detector, and creates a total ion chromatogram (TIC) by summing the intensities of the ions detected during one mass scan using the mass spectrometry data obtained by the mass spectrometer (step 102).

[0020] Next, the data processing unit 10 detects peak portions that form peak-shaped waveforms in each of the chromatogram and the TIC (step 103). For the detection of the peak portions, a method such as detecting the peak start point, peak top, and peak end point based on the slope of the chromatogram can be used. After detecting the peak portions in each of the chromatogram and the TIC, the data processing unit 10 associates the peak portions on the chromatogram with the peak portions on the TIC in consideration of the delay time until the component that has passed through the detector flows into the mass spectrometer (step 104). For example, the delay time is subtracted from the elution time of the TIC, and the peaks having substantially the same elution time between the peak portions on the chromatogram and the peak portions on the TIC are associated with each other.

[0021] Next, the data processing unit 10 calculates a mask chromatogram within the range from the start point to the end point of each peak portion on the TIC, and detects peaks included in each peak portion on the TIC (step 105). Then, the data processing unit 10 determines the number of components included in each peak portion on the TIC by comparing the peak top retention times of the mask chromatograms in which peaks are detected for each peak portion. When determining the number of components included in each peak portion, if the difference in the peak retention times of the mask chromatograms is within a certain range, it is determined that they are of the same component, and mask chromatograms in which the difference in the peak top retention times exceeds the certain range are determined to be of different components. When the data processing unit 10 determines that a plurality of components are included in a single peak portion, it determines that it is co-elution, and specifies the peak portion as a co-elution peak (step 106).

[0022] In the process of the above processing, mask chromatograms of components included in each peak portion are extracted by the data processing unit 10 and stored in a predetermined data storage area. When there are a plurality of mask chromatograms for the same component, the mask chromatogram with the maximum signal intensity mass-to-charge ratio is extracted as the mask chromatogram of the component.

[0023] When the information display unit 12 displays a chromatogram on the display 6, for example, in accordance with a request from the user, the information display unit 12 color-codes the peak portions specified as co-elution peaks by the data processing unit 10 from other peak portions (step 107), and displays a chromatogram in a state where the user can visually distinguish between the peak portions that are co-elution peaks and those that are not on the display 6 (step 108).

[0024] FIG. 4 is an example of a chromatogram displayed on the display 6 in a state where the peak portions specified as co-elution peaks and other peak portions are color-coded. In this example, only the peak portions specified as co-elution peaks are colored, and it is clear whether co-elution peaks exist and which peak portions are co-elution peaks.

[0025] Furthermore, as shown in Figure 3, when the user specifies an arbitrary peak portion on the mask chromatogram displayed on the display 6, the information display unit 12 reads the mask chromatograms of the components contained in the specified peak portion from a predetermined data storage area (step 201), and displays the read mask chromatograms on the same screen as the chromatogram (step 202). If the user specifies a co-elution peak, as shown in Figure 5, the mask chromatograms of each of the multiple components contained in that co-elution peak are displayed. The mask chromatogram displayed on the same screen as the chromatogram also shows the mass electrification ratio of the component. This allows the user to easily confirm what mass electrification ratios the components with co-eluting have.

[0026] Furthermore, the data processing unit 10 has the function of creating a peak table that lists information about each peak portion on the chromatogram, and the information display unit 12 has the function of displaying the peak table created by the data processing unit 10 on the display 6 according to a request from the user. Figure 6 is an example of a peak table displayed on the display 6. The information shown in the peak table includes information on whether each peak portion on the chromatogram is a co-elution peak or not. This allows the user to easily obtain information such as whether the chromatogram contains co-elution peaks and which peak portions are co-elution peaks, not only from the color coding on the chromatogram but also from the peak table.

[0027] Furthermore, the data storage unit 8 can store multiple analytical data obtained using different analytical methods for the same component. In this case, the data processing unit 10 can create multiple chromatograms for each analytical method using the multiple analytical data for the same component stored in the data storage unit 8, and perform peak identification to correlate the peaks appearing in each of the multiple chromatograms. In peak identification, one of the multiple chromatograms is designated as the reference chromatogram, and each peak in the other chromatograms is identified as corresponding to a peak in the reference chromatogram. This peak identification can be performed using peak area, peak height, peak area % (the ratio of the area of ​​the peak to the total area of ​​all peaks on the same chromatogram), height % (the ratio of the height of the peak to the total height of all peaks on the same chromatogram), peak No. (elution rank), UV spectrum similarity, mass spectrum similarity, mass electrification ratio of the base peak of the mass spectrum, etc. The user may be able to arbitrarily set whether or not to include co-eluting peaks as the target of such peak identification. In that case, if the user sets the system to exclude co-elution peaks from peak identification, the data processing unit 10 will exclude the co-elution peaks from peak identification.

[0028] The embodiments described above are merely examples of embodiments of the data processing system according to the present invention. Embodiments of the data processing system according to the present invention are as follows.

[0029] In one embodiment of the data processing system according to the present invention, the data processing system comprises: a data holding unit that holds mass analysis data acquired by a mass spectrometer and measurement data acquired by a detector other than a mass spectrometer as analysis data by analyzing a sample using a chromatograph-mass spectrometer; a data processing unit configured to perform data processing using the analysis data held in the data holding unit; and an information display unit configured to display the data processed by the data processing unit, wherein the data processing unit is configured to create a chromatogram based on the measurement data, and to identify as a co-elution peak a peak portion on the chromatogram where the peaks of multiple components overlap to form a single peak shape using the correspondence between the chromatogram and the mass analysis data; and the information display unit is configured to display the peak portion identified as the co-elution peak by the data processing unit in a different manner from other peak portions when displaying the chromatogram, thereby allowing the user to visually recognize whether each peak portion on the chromatogram is the co-elution peak or not.

[0030] In the first embodiment of the above-described embodiment, the information display unit is configured to assign a different color to the peak portion identified as the co-elution peak compared to the other peak portions.

[0031] In the second aspect of the above embodiment, the data processing unit is configured to extract the mask chromatograms of the components contained in each peak portion of the chromatogram from the mass spectrometry data, and the information display unit is configured to display the mask chromatograms of the components contained in the specified peak portion alongside the chromatogram when a peak portion is specified by the user on the chromatogram. This makes it easy to check what mass electrification ratios the components containing are in each peak portion of the chromatogram.

[0032] In the third aspect of the above embodiment, the data processing unit is configured to create a peak table based on the analysis data, which includes peak information for each peak portion on the chromatogram and information indicating whether or not each peak portion is the co-elution peak, and the information display unit is configured to display the peak table created by the data processing unit based on a request from the user.

[0033] In the fourth aspect of the above embodiment, the data holding unit holds multiple analytical data obtained by analyzing the same sample using multiple different analytical methods with the chromatograph-mass spectrometer, the data processing unit is configured to create multiple chromatograms based on each of the multiple analytical data, designate one of the multiple chromatograms as a reference chromatogram, and perform peak identification to determine which of the peak portions on the reference chromatogram corresponds to the peak portion on the reference chromatogram. The user can set in advance whether or not to exclude co-elution peaks from the target of peak identification, and if it is set in advance to exclude co-elution peaks from the target of peak identification, the data processing unit is configured to exclude the peak portion identified as the co-elution peak from the target of peak identification. [Explanation of symbols]

[0034] 1. Data Processing System 2 Data Processing Devices 4 Input devices 6 displays 8. Data storage unit 10 Data Processing Unit 12 Information display section 100 LC-MS

Claims

1. A data storage unit that stores, as analytical data, the mass analysis data acquired by the mass spectrometer and the measurement data acquired by a non-mass spectrometer detector by analyzing a sample using a chromatographic mass spectrometer, A data processing unit configured to perform data processing using the analysis data held in the data holding unit, A data processing system comprising an information display unit configured to display data processed by the data processing unit, The data processing unit is configured to create a chromatogram based on the measurement data, and to use the correspondence between the chromatogram and the mass spectrometry data to identify as a co-elution peak a peak portion on the chromatogram in which multiple component peaks overlap to form a single peak shape. The information display unit is configured to display the peak portion identified as the co-elution peak by the data processing unit in a manner different from other peak portions when displaying the chromatogram, thereby allowing the user to visually recognize whether each peak portion on the chromatogram is the co-elution peak. The data processing unit is configured to extract the mass chromatograms of the components contained in each peak portion of the chromatogram from the mass spectrometry data. A data processing system wherein the information display unit is configured to allow the user to individually specify each peak portion on the chromatogram when the chromatogram is displayed, and when the user specifies a co-elution peak on the chromatogram, the mask chromatograms of each of the multiple components included in the specified co-elution peak are displayed on the same screen as the chromatogram but in a different position from the chromatogram.

2. The data processing system according to claim 1, wherein the information display unit is configured, in the different embodiment, to assign a different color to the peak portion identified as the co-elution peak compared to the other peak portions.

3. The data processing unit is configured to create a peak table based on the analysis data, which includes peak information for each peak portion on the chromatogram and information indicating whether or not each peak portion is a co-elution peak. The data processing system according to claim 1, wherein the information display unit is configured to display the peak table created by the data processing unit based on a request from the user.

4. The data storage unit stores multiple analytical data obtained by analyzing the same sample using multiple different analytical methods with the chromatograph-mass spectrometer. The data processing unit is configured to create multiple chromatograms based on each of the multiple analysis data, designate one of the multiple chromatograms as the reference chromatogram, and perform peak identification to determine which of the peak portions on the reference chromatogram corresponds to the peak portions on the chromatograms other than the reference chromatogram. The system is configured so that the user can pre-set whether or not to exclude co-elution peaks from the target of peak identification. The data processing system according to claim 1, wherein, if it is predetermined that the co-elution peak be excluded from the target of peak identification, the data processing unit is configured to exclude the peak portion identified as the co-elution peak from the target of peak identification.

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