JP4057664B2 - Data processing device for chromatograph / mass spectrometer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a data processing apparatus in a chromatograph / mass spectrometer in which a gas chromatograph or liquid chromatograph is connected to a mass spectrometer.
[0002]
[Prior art]
As a method for quantitative analysis using a gas chromatograph / mass spectrometer (GC / MS) or a liquid chromatograph / mass spectrometer (LC / MS), measurement in a selected ion monitoring (SIM) mode is performed. In SIM, a mass number (m / z) for quantification is selected in advance for a compound (target compound) to be quantified, and a chromatogram showing a change in intensity over time at the mass number is measured. Then, the peak area of the chromatogram is calculated, and the target compound is quantified based on a calibration curve prepared in advance.
[0003]
When performing quantitative analysis in the SIM mode, first, the standard sample is measured in the scanning mode performed while scanning the mass number, and the total ion intensity is accumulated at each time point to create a total ion chromatogram (TIC). The operator searches for the peak of the target compound from the chromatogram, and obtains the retention time. Then, parameters required in SIM mode for each target compound (quantitative mass number to be monitored, switching time to the mass number of each target compound), and quantitative parameters (target compound name, mass number for quantification, mass number for confirmation, Waveform processing range and holding time) are determined and set by the operator inputting from the keyboard.
[0004]
[Problems to be solved by the invention]
The search for the peak of the target compound from the total ion chromatogram by the operator is a complicated and time-consuming operation as the number of compounds increases. Then, every time the type of chromatographic column or the separation condition is changed, it is necessary to reset the SIM parameter and the quantitative parameter.
Accordingly, an object of the present invention is to enable automatic setting of quantitative parameters and SIM parameters.
[0005]
[Means for Solving the Problems]
In the present invention, a database of information on the target compound is created in advance, and when a standard sample is measured, the peak of the target compound is automatically found from the total ion chromatogram based on the database. Further, parameters necessary for the SIM mode and quantification parameters are automatically determined based on the results of peak identification and a database.
[0006]
Therefore, as shown in FIG. 1, the data processing apparatus of the present invention shows a database including the name, mass spectrum, quantitative mass number and confirmation mass number of each target compound, and the number of points at the time of creating a calibration curve. Includes the number of levels, concentration of each level, calibration method, type of regression equation, allowable range of retention time, allowable range of intensity ratio between peak at mass number for quantification and peak at mass number for confirmation, and waveform processing range A total ion chromatogram is created from the data in the scan mode of the chromatograph / mass spectrometer 4 when the standard sample is measured and the storage unit 2 for storing quantitative parameters, and the peak of the total ion chromatogram The peak spectrum of the target compound to be quantified is compared with the mass spectrum of the database stored in the storage unit 2. A peak identification unit 6 for searching for peaks, a standard retention time in the total ion chromatogram for the peak of the target compound obtained as a result of peak identification by the peak identification unit 6, a mass number for quantification in the database of the storage unit 2, and A quantification table creation unit 8 that creates a quantification table composed of the confirmation mass number and each parameter in the quantification parameters stored in the storage unit 2, and a parameter obtained from the obtained total ion chromatogram, which is a SIM mode And a SIM parameter creating unit 10 for determining parameters necessary for measuring the target compound at the quantification mass number and the confirmation mass number.
[0007]
The operation of the present invention will be described.
First, the mass spectrum of each target compound, the mass number for quantification for measuring the chromatogram in the SIM mode, and the peak of the chromatogram being measured at the mass number for quantification are compared with the peak value at the mass number for quantification. The confirmation mass number for confirming that it is the target compound and the compound name of the target compound are input from the keyboard and stored in the storage unit 2 as a database. Once a database is created, it can be used repeatedly.
[0008]
Parameters for quantification (number of levels indicating the number of points when creating a calibration curve, concentration of each level, calibration method, type of regression equation, allowable range of retention time, peak in quantification mass number and confirmation mass number The allowable range of the intensity ratio with respect to the peak and the waveform processing range) are also input from the keyboard and stored in the storage unit 2.
[0009]
Next, measurement is performed in a scan mode in which the standard sample is scanned in the range of a preset mass number. The subsequent operation will be described with reference to FIGS. Since a mass spectrum is obtained at each time point by measuring a standard sample in the scan mode, the total ion chromatogram is obtained as a change with time as shown in FIG. 3 (A) by integrating the ion intensity at each time point. Is obtained.
[0010]
Peak detection is performed on the total ion chromatogram. A spectrum search is performed using the mass spectrum information in the database for the mass spectrum at the peak top of the detected peak, and it is identified which target compound the peak is. These processes are performed by the peak identification unit 6 based on the database stored in the storage unit 2. The peak identification result is displayed on a printer or CRT, and an error message can also be output in the following cases.
a. Some target compounds have not been identified as peaks.
b. When the same target compound is identified by multiple peaks.
c. As a result of the identification, the similarity (the similarity between the spectrum of the peak obtained by analyzing the standard sample and the spectrum of the database) is lower than a predetermined reference value.
[0011]
When an error message is output, the operator can confirm and correct the peak identification result with reference to the result of the error message.
When it is confirmed which peak of the total ion chromatogram the target compound corresponds to, the quantification table creation unit 8 is a total ion chromatogram for the peak of the target compound obtained as a result of peak identification by the peak identification unit 6. A quantification table is created that includes the standard retention time, the quantification mass number and the confirmation mass number in the database, and each parameter in the quantification parameter. The quantitative table is, for example, as shown in FIG.
[0012]
Next, the SIM parameter creation unit 10 determines SIM parameters necessary for performing measurement at the quantification mass number and the confirmation mass number of each target compound in the selected ion monitoring mode based on the total ion chromatogram. To do. The SIM parameter is determined as shown in FIG. 3C, for example. The ion set indicates the chromatogram peak of each target compound, and in order to measure each peak, the measurement is performed at the start mass (start time) and end time (measurement time). End time) is automatically determined.
[0013]
In the total ion chromatogram shown in FIG. 3A, when a part of the peaks overlaps, a time including the overlapping peaks is set, and the mass number for quantification of all the target compounds corresponding to the overlapping peaks at that time is set. And the mass number for confirmation may be measured.
[0014]
【Example】
FIG. 4 schematically shows an embodiment. The chromatograph / mass spectrometer 4 is GC / MS or LC / MS. The CPU 12 controls the operation of the chromatograph / mass spectrometer 4 and processes data obtained from the mass spectrometer of the chromatograph / mass spectrometer 4. Reference numeral 14 denotes a storage device that stores a program necessary for control, a database and quantitative parameters in the present invention, as well as a quantitative table and SIM parameters created in the present invention. Reference numeral 16 denotes an input keyboard for setting a database and quantitative parameters, and reference numeral 18 denotes a printer that outputs the created quantitative table and SIM parameters.
The storage unit 2 in FIG. 1 corresponds to the storage device 14, and the peak identification unit 6, the quantitative table creation unit 8, and the SIM parameter creation unit 10 are realized by the CPU 12 and the storage device 14.
[0015]
【The invention's effect】
In the present invention, by simply setting a target compound database and parameters for quantification in advance, the quantitation table and SIM parameters can be automatically determined by measuring standard compounds. The troublesome work of resetting each time the column type or separation condition is changed can be omitted.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating the present invention.
FIG. 2 is a flowchart showing the operation of the present invention.
FIGS. 3A and 3B are diagrams showing an operation, in which FIG. 3A is a total ion chromatogram, FIG. 3B is a chart showing a quantitative table to be created, and FIG. 3C is a chart of SIM parameters to be created.
FIG. 4 is a block diagram showing an embodiment.
[Explanation of symbols]
2 Storage Unit 4 Chromatograph / Mass Spectrometer 6 Peak Identification Unit 8 Quantitative Table Creation Unit 10 SIM Parameter Creation Unit

Claims (1)

Database containing the name, mass spectrum, quantitative mass number and confirmation mass number of each target compound, number of levels indicating the number of points when creating a calibration curve, concentration of each level, calibration method, type of regression equation, retention time A storage unit for storing a tolerance parameter, a quantitative parameter including a peak at the mass number for quantification and an intensity ratio between the peak at the mass number for confirmation and a waveform processing range;
A total ion chromatogram is created from the data in the scan mode of the chromatograph / mass spectrometer when the standard sample is measured, and the peak top mass spectrum of the peak of the total ion chromatogram is compared with the mass spectrum of the database. A peak identification unit for searching for the peak of the target compound to be quantified,
Standard retention time in the total ion chromatogram for the peak of the target compound obtained as a result of peak identification by the peak identification unit, quantification mass number and confirmation mass number in the database, and each parameter in the quantification parameter A quantitative table creation unit for creating a quantitative table comprising:
A SIM parameter creation unit for determining parameters required from the total ion chromatogram, which are parameters required for performing measurement at the quantification mass number and the confirmation mass number of each target compound in the selected ion monitoring mode; A data processing apparatus for a chromatograph / mass spectrometer, comprising:

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