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EP-4737894-A1 - DATA PROCESSING DEVICE, MASS SPECTROMETRY SYSTEM, AND MASS SPECTROMETRY DATA PROCESSING METHOD

EP4737894A1EP 4737894 A1EP4737894 A1EP 4737894A1EP-4737894-A1

Abstract

In order to enable highly accurate mass spectrometry, this mass spectrometry system comprises: a plot processing unit (212) that plots quadrupole RF voltage acquired as a result of measuring a plurality of calibration ions, for which m/z is known, using a mass spectrometer (100) and m/z of each of the calibration ions as calibration points at coordinates having quadrupole RF voltage and m/z as coordinate axes; a correction processing unit (213) that corrects the calibration points by correcting an outlier if there is an outlier with respect to the calibration points; and a measurement processing unit (213) that measures the calibration ions using the mass spectrometer (100) in a scan range centered on the quadrupole RF voltage calculated using the corrected calibration points.

Inventors

  • SUGIYAMA, MASUYUKI
  • HASEGAWA, HIDEKI
  • TOMA, Tsugunao
  • HASHIMOTO, YUICHIRO

Assignees

  • HITACHI HIGH-TECH CORPORATION

Dates

Publication Date
20260506
Application Date
20240621

Claims (10)

  1. A data processing device comprising: a plot processing unit configured to plot voltages acquired as a result of measuring a plurality of calibration ions having known m/z values by a mass spectrometer and the m/z values of the respective calibration ions as calibration points on coordinates having the voltages and the m/z values as coordinate axes; and a correction processing unit configured to correct the calibration points by correcting outliers if there are outliers for the respective calibration points.
  2. The data processing device according to claim 1, further comprising a measurement processing unit that performs measurement of the calibration ions by the mass spectrometer in a voltage range centered on the voltage calculated by the corrected calibration point.
  3. The data processing device according to claim 2, wherein the measurement processing unit changes the voltage range so that the voltage range gradually becomes a wider range every time the measurement is performed.
  4. The data processing device according to claim 1, wherein the correction processing unit calculates a slope between the calibration points, calculates a deviation regarding each of the slopes, determines that there is the outlier when a standard deviation of the deviation is larger than a preset threshold value, and corrects the calibration point based on the slope.
  5. The data processing device according to claim 1, wherein the correction processing unit calculates a slope and an intercept by applying a least squares method to each of the calibration points, calculates a distance from a straight line having the slope and the intercept as a deviation for each of the calibration points, and corrects the calibration point based on the slope when a standard deviation of the deviation is larger than a preset threshold value.
  6. A mass spectrometry system comprising: a mass spectrometer; a plot processing unit configured to plot voltages acquired as a result of measuring a plurality of calibration ions having known m/z values by the mass spectrometer and the m/z values of the respective calibration ions as calibration points on coordinates having the voltages and the m/z values as coordinate axes; and a correction processing unit configured to correct the calibration points by correcting outliers if there are outliers for the respective calibration points.
  7. The mass spectrometry system according to claim 6, further comprising a measurement processing unit that measures the calibration ions by the mass spectrometer in a voltage range centered on the voltage calculated by the corrected calibration point.
  8. The mass spectrometry system according to claim 6, wherein the mass spectrometer has a quadrupole mass filter or a time-of-flight mass spectrometer in an analysis unit.
  9. A mass spectrometry data processing method comprising: a first step of plotting, by a data processing device, voltages acquired as a result of measuring a plurality of calibration ions having known m/z values by a mass spectrometry device and the m/z values of the respective calibration ions as calibration points on coordinates having the voltages and the m/z values as coordinate axes; and a second step of correcting the calibration points by correcting outliers if there are outliers for the respective calibration points.
  10. The mass analysis data processing method according to claim 9, further comprising a third step of measuring the calibration ions by the mass spectrometer in a voltage range centered on the voltage calculated by the corrected calibration point.

Description

FIELD OF THE INVENTION The present invention relates to a technique of a data processing device, a mass spectrometry system, and a mass spectrometry data processing method. BACKGROUND OF THE INVENTION In a mass spectrometer, ions having a known m/z are measured, and the relationship between a specific parameter (a voltage applied to an electrode in a quadrupole mass filter) and the m/z is determined. In the measurement of a sample of unknown m/z, the m/z is determined by using such a technique. Patent Document 1 describes that "the ionization unit 21 is controlled by the ionization control unit 1 so as to ionize an analysis sample and a mass calibration sample as analysis sample ions and mass calibration sample ions. An ion trap 23 is controlled by an ion dissociation control part 2 so as to capture an analysis sample ion and a mass calibration sample ion and selectively dissociate the mass calibration sample ion into a plurality of calibration fragment ions without selecting the analysis sample ion as a precursor ion. The mass analyzer 24 is controlled by the analysis control unit 3 so that the mass analysis of the analysis sample ions and the plurality of calibration fragment ions is performed. The mass-to-charge ratio of the analysis sample ion is calibrated by the calibration unit 4 based on the mass-to-charge ratios of the plurality of calibration fragment ions in the mass analysis spectrum obtained by the mass analysis. "(see Abstract). Patent Document 2 discloses a method of measuring a mass spectrum under a plurality of conditions with different ionization polarities and the like, and performing mass axis calibration when there is a difference from reference data. Prior Art Document Patent Document Patent Document 1: Japanese Patent Application Laid-Open No. 2019-86467Patent Document 2: U.S. Patent Application Publication No. 2022 / 0246412 SUMMARY OF THE INVENTION Problems to be solved by the invention It is an object of the invention to determine an accurate mass axis even when an impurity ion whose m / z is adjacent to a calibration point exists when performing mass axis calibration. In the technique described in Patent Document 1, since sample ions and impurity ions coexist, when the m / z of the fragment ions for calibration and the m / z of the impurity ions are adjacent to each other, there is a case where an accurate mass axis cannot be determined due to a mistake of peaks. In the technique described in Patent Document 2, when the m / z of the calibration sample ion and the m / z of the impurity ion are adjacent to each other, it is not possible to determine which of the peaks of the adjacent spectra is the calibration sample ion. Therefore, in the technique described in Patent Document 2, even if an abnormality can be detected from a difference from the reference data, it is not possible to obtain confirmation that the ion is a calibration sample ion. The present invention has been made in view of such a background, and an object of the present invention is to enable mass spectrometry with high accuracy. Means to solve the problem In order to solve the above-described problem, the present invention includes a plot processing unit that plots voltages acquired as a result of measuring a plurality of calibration ions having known m / z values by a mass spectrometer and the m / z values of the respective calibration ions as calibration points on coordinates having the voltages and the m / z values as coordinate axes, and a correction processing unit that corrects the calibration points by correcting outliers when there are outliers for the respective calibration points. Other solutions will be described in the embodiments as appropriate. Advantage of the Invention According to the present invention, mass spectrometry with high accuracy can be performed. BRIEF DESCRIPTION OF THE DRAWINGS [Fig. 1] Fig. 1 is a diagram showing a configuration example of a mass spectrometry system according to a first embodiment.[Fig. 2] Fig. 2 is a diagram illustrating an example of a hardware configuration of a data processing device;[Fig. 3A] Fig. 3A is a diagram (part 1) showing a configuration of a quadrupole mass filter.[Fig. 3B] Fig. 3B is a diagram (part 2) showing the configuration of a quadrupole mass filter.[Fig. 4] Fig. 4 shows the operation of a quadrupole mass filter as a function of the quadrupole RF and DC voltages.[Fig. 5] Fig. 5 is a graph showing the relationship between the quadrupole RF voltage and the ion signal intensity.[Fig. 6] Fig. 6 is a graph (part 1) showing the relationship between m/z and quadrupole RF voltage.[Fig. 7A] Fig. 7A is a diagram (part 2) showing a graph of m/z-quadrupole RF voltage relation.[Fig. 7B] Fig. 7B is a diagram (part 3) showing a graph of m/z-quadrupole RF voltage relation.[Fig. 8] Fig. 8 is a flowchart showing a procedure of a mass spectrometry data processing method according to the first embodiment.[Fig. 9A] Fig. 7A is a diagram showing a table of specific valu