Data processing device, mass spectrometry system, and mass spectrometry data processing method

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.

Description

Data processing device, mass spectrometry system and mass spectrometry data processing method

[0001] The present invention relates to the techniques of a data processing device, a mass spectrometry system, and a mass spectrometry data processing method.

[0002] In a mass spectrometer, ions of known m / z are measured and the relationship between a specific parameter (the voltage applied to the electrodes in a quadrupole mass filter) and m / z is determined. When measuring a sample of unknown m / z, the m / z can be determined by using this technique.

[0003] Patent Document 1 discloses a mass analysis control device, a mass analysis device, a mass analysis control method, and a mass analysis method, in which "an ionization controller 1 controls an ionization unit 21 to ionize an analytical sample and a mass calibration sample as analytical sample ions and mass calibration sample ions. An ion dissociation controller 2 controls an ion trap 23 to trap the analytical sample ions and mass calibration sample ions and to selectively dissociate the mass calibration sample ions into a plurality of calibration fragment ions without selecting the analytical sample ions as precursor ions. An analysis controller 3 controls a mass analyzer 24 to perform mass analysis of the analytical sample ions and the plurality of calibration fragment ions. The mass-to-charge ratio of the analytical sample ions is calibrated by a calibration unit 4 based on the mass-to-charge ratios of the plurality of calibration fragment ions in a mass analysis spectrum obtained by mass analysis" (see Abstract).

[0004] Patent Document 2 discloses a method of measuring mass spectra under a plurality of conditions with different ionization polarities, etc., and performing mass axis calibration if there is a difference from the reference data.

[0005] JP 2019-86467 A U.S. Patent Application No. 2022 / 0246412

[0006] The problem to be solved by the present invention is to determine an accurate mass axis when performing mass axis calibration even when there are impurity ions whose m / z values ​​are adjacent to the calibration point.

[0007] In the technology described in Patent Document 1, sample ions and impurity ions coexist, and if the m / z of the calibration fragment ions and the impurity ions are adjacent, the accurate mass axis may not be determined due to peak confusion.

[0008] In the technology described in Patent Document 2, when the m / z of the calibration sample ion and the m / z of the impurity ion are adjacent, it is not possible to determine which of the adjacent spectral peaks is the calibration sample ion. Therefore, even if the technology described in Patent Document 2 can detect an abnormality from the difference with the reference data, it cannot be certain that the ion is the calibration sample ion.

[0009] The present invention has been made in view of the above background, and an object of the present invention is to enable highly accurate mass analysis.

[0010] In order to solve the above-mentioned problems, the present invention includes a plotting processing unit that plots voltages obtained as a result of measuring a plurality of calibration ions with known m / z values ​​using a mass spectrometer and the m / z values ​​of each calibration ion as calibration points on a coordinate system having the voltages and the m / z values ​​as coordinate axes, and a correction processing unit that corrects outliers, if any, for each of the calibration points, thereby correcting the calibration points. Other means for solving the problems will be described as appropriate in the embodiments.

[0011] According to the present invention, highly accurate mass analysis becomes possible.

[0012] FIG. 1 is a diagram showing an example of the configuration of a mass spectrometry system according to the first embodiment. FIG. 2 is a diagram showing an example of the hardware configuration of a data processing device. FIG. 3 is a diagram showing the relationship between the operation of the quadrupole mass filter and the quadrupole RF voltage and quadrupole DC voltage. FIG. 4 is a diagram showing a quadrupole RF voltage-ion signal intensity relationship graph showing the relationship between the quadrupole RF voltage and the ion signal intensity. FIG. 1 is a diagram showing an m / z-quadrupole RF voltage relationship graph. FIG. 2 is a diagram showing an m / z-quadrupole RF voltage relationship graph. FIG. 3 is a diagram showing an m / z-quadrupole RF voltage relationship graph. FIG. 4 is a flowchart showing the procedure of a mass spectrometry data processing method according to the first embodiment. FIG. 5 is a diagram showing a table of specific values ​​of calibration points. FIG. 6 is a diagram showing a deviation graph. FIG. 7 is a diagram showing a voltage calibration technique. FIG. 8 is a flowchart showing the procedure of a mass spectrometry data processing method according to the second embodiment. FIG. 9 is a diagram showing an m / z-quadrupole RF voltage relationship graph. FIG. 10 is a diagram showing the procedure of a mass spectrometry data processing method according to the third embodiment.

[0013] Next, a mode for carrying out the present invention (referred to as an "embodiment") will be described in detail with reference to the drawings as appropriate.

[0014] First Embodiment [Mass Spectrometry System 1] Fig. 1 is a diagram showing an example of the configuration of a mass spectrometer system 1 according to the first embodiment. The mass spectrometer system 1 includes a mass spectrometer 100, a voltage control device 300, DC power supplies 301 and 303, and an RF power supply 302. The mass spectrometer system 1 also includes a data processing device 200 to which an output device 201 is connected. In Fig. 1, the dashed lines connecting the voltage control device 300 to the DC power supplies 301 and 303, the RF power supply 302, and the data processing device 200, as well as the dashed line connecting the detector 152 to the data processing device 200, represent signal lines. The solid line connecting the DC power supply 303 to the ion guide 130 and the solid lines connecting the RF power supply 302 to the quadrupole mass filter 140 and the DC power supply 301 represent electric wires to which voltages are applied.

[0015] The mass spectrometer 100 has an ion source 151, a first differential pumping unit 101, a second differential pumping unit 102, and an analyzing unit 103. Ions generated in the ion source 151 are introduced into the first differential pumping unit 101 through an aperture 121. The ion source 151 is composed of an electrospray ion source, an atmospheric pressure chemical ion source, an atmospheric pressure photoionization source, an atmospheric pressure matrix-assisted laser desorption ion source, or the like, and operates at atmospheric pressure or a vacuum lower than atmospheric pressure.

[0016] The first differential pumping unit 101 is evacuated by a pump 111. As a result, the first differential pumping unit 101 is maintained at a vacuum level of 10 Pa to 500 Pa. Ions that have passed through the first differential pumping unit 101 are introduced into the second differential pumping unit 102 via an aperture 122. The second differential pumping unit 102 is evacuated by a pump 112. As a result, the second differential pumping unit 102 is maintained at a vacuum level of 0.1 Pa to 10 Pa. An ion guide 130 that focuses ions is installed in the second differential pumping unit 102. The ions focused by the ion guide 130 are introduced via an aperture 123 into the analysis unit 103 in which a quadrupole mass filter 140 is installed.

[0017] A static voltage (hereinafter referred to as DC voltage) is applied to the ion guide 130 from a DC power supply 303. The RF power supply 302 applies to the quadrupole mass filter 140 a composite wave of a radio frequency voltage (hereinafter referred to as RF voltage) generated by the RF power supply 302 and a DC voltage sent from the DC power supply 301.

[0018] 1, the ion guide 130 and quadrupole mass filter 140 are connected via a dielectric 153 such as a capacitor. As described above, RF voltage is supplied to the quadrupole rod electrodes 141 of the quadrupole mass filter 140 (see FIGS. 3A and 3B) from an RF power supply 302 controlled by a voltage control device 300. The high-frequency component of the RF voltage is then supplied from the quadrupole rod electrodes 141 to the ion guide rod electrodes of the ion guide 130 through the dielectric 153. With this configuration, the number of power supplies can be reduced compared to a configuration in which RF voltage is supplied separately to the ion guide 130 and the quadrupole mass filter 140, making the mass spectrometry system 1 less expensive.

[0019] The analyzer 103 is evacuated by a pump 113. As a result, the analyzer 103 is maintained at a pressure of 1E-3 Pa or less. In the quadrupole mass filter 140, ions are separated according to m / z.

[0020] Ions that pass through the quadrupole mass filter 140 are detected by the detector 152. The detector 152 can generally be an electron multiplier, a combination of a scintillator and a photomultiplier, or a multichannel plate. The detection intensity of the ions detected by the detector 152 is converted into an electrical signal (output signal) and sent to the data processing device 200. The output signal from the detector 152 is converted into digital data at a fixed sampling period (typically 1 μs to 1000 μs) and then sent to the data processing device 200. The conversion to digital data is performed by an analog-to-digital converter (ADC) (not shown) or a pulse counting unit (not shown). The data processing device 200 stores the sent digital data in a memory unit 220.

[0021] In the data processing device 200, in addition to the memory unit 220, a plot processing unit 211, a correction processing unit 212, and a measurement processing unit 213 are executed. The plot processing unit 211 plots calibration points 521 (FIGS. 6 to 7B) on the m / z-quadrupole RF voltage relationship graphs shown in FIGS. 6 to 7B. The correction processing unit 212 corrects the calibration points 521 based on the calibration points 521 plotted by the plot processing unit 211. The measurement processing unit 213 controls the measurement by the mass spectrometer 100.

[0022] The storage unit 220 is composed of a memory, a hard disk, etc., and can store and hold not only the data of the spectrum 501 (see FIG. 5 ) but also information such as numerical values ​​and relational expressions required for correction. The plot processing unit 211, the correction processing unit 212, and the measurement processing unit 213 each have a temporary memory for temporarily storing numerical values ​​required for calculation functions and calculations. Furthermore, the data processing device 200 not only stores and converts this information, but also has the function of controlling the voltage control device 300 that controls each electrode, etc., and the function of outputting information to the output device 201. The output device 201 is composed of a display, a printer, etc. The output device 201 outputs information such as the spectrum 501 itself, the m / z corresponding to the peak of the spectrum 501, the signal intensity, and the presence or absence of the substance to be measured.

[0023] 1, the storage unit 220 is mounted on the data processing device 200, but this is not limiting. For example, the storage unit 220 may be installed as a device separate from the data processing device 200, such as a database.

[0024] 2 is a diagram showing an example of the hardware configuration of the data processing device 200. The data processing device 200 includes a memory 231 configured with a RAM or the like, an arithmetic unit 232 configured with a CPU, a GPU or the like, and a storage device 233 configured with a HD, an SSD or the like. The data processing device 200 also includes an input device 234 configured with a keyboard, a mouse or the like, an output device 201, and a communication device 235.

[0025] When the data processing device 200 is equipped with the storage unit 220 (see FIG. 1), the storage device 233 corresponds to the storage unit 220. The output device 201 is the output device 201 shown in FIG.

[0026] Furthermore, a program stored in the storage device 233 is loaded into the memory 231. The loaded program is then executed by the arithmetic unit 232. This embodies the plot processing unit 211, the correction processing unit 212, and the measurement processing unit 213 shown in FIG.

[0027] [Quadrupole Mass Filter 140] Figures 3A and 3B are diagrams showing the configuration of the quadrupole mass filter 140. Figure 3A shows a perspective view of the quadrupole mass filter 140, and Figure 3B shows a cross-section of the quadrupole mass filter 140 and a diagram showing voltage control for the quadrupole mass filter 140. As shown in Figures 3A and 3B, the quadrupole mass filter 140 is composed of four quadrupole rod electrodes 141 (141a to 141d). As shown in Figure 3B, an RF voltage and a DC voltage are applied to each quadrupole rod electrode 141. The RF voltage is an AC voltage generated by an RF power supply 302 controlled by a voltage control device 300. The DC voltage is a DC voltage generated by a DC power supply 301 controlled by the voltage control device 300. In practice, a composite wave in which the DC voltage is applied to the RF voltage is applied to each quadrupole rod electrode 141.

[0028] The composite wave of the RF voltage and the DC voltage is applied so that it is in phase with each other between adjacent quadrupole rod electrodes 141 and in phase with each other between opposing quadrupole rod electrodes 141. That is, in the example shown in Fig. 3B, RF voltages of opposite phases are applied between the pair of quadrupole rod electrodes 141a and 141c and the pair of quadrupole rod electrodes 141b and 141d.

[0029] As described above, the DC voltage is a direct current voltage generated by a DC power supply 301 controlled by a voltage control device 300. Here, if the DC voltage applied to the quadrupole rod electrodes 141a and 141c is VDC1, the DC voltage applied to the quadrupole rod electrodes 141b and 141d is −VDC1. The RF voltage and DC voltage applied to each quadrupole rod electrode 141 are appropriately referred to as a quadrupole RF voltage and a quadrupole DC voltage. The quadrupole RF voltage typically has a voltage amplitude of several hundred volts to several kV and a frequency of approximately 500 kHz to 2 MHz. The quadrupole DC voltage is approximately several tens of volts to several hundreds of volts.

[0030] (Operation of the Quadrupole Mass Filter 140) Next, the operation of the quadrupole mass filter 140 will be described with reference to FIG. 4. FIG. 4 is a diagram showing the relationship between the operation of the quadrupole mass filter 140 and the quadrupole RF voltage and quadrupole DC voltage. The m / z range of ions capable of stable orbital motion within the quadrupole mass filter 140 depends on the amplitude of the quadrupole RF voltage and the value of the quadrupole DC voltage. Only ions within the stability regions R1 to R3 shown in FIG. 4 can pass through the quadrupole mass filter 140. Here, stability region R1 is the region within line R1a, stability region R2 is the region within line R2a, and stability region R3 is the region within line R3a. Stability regions R1 to R3 differ depending on the m / z of the ion. Stability regions R1 to R3 are arranged according to the relationship shown in FIG. 4, from small m / z ions to large m / z ions. In other words, stability region R1 is the stability region for ions having a certain m / z. Similarly, stability region R2 is a stability region for ions having m / z values ​​different from those of ions in stability region R1, and stability region R3 is a stability region for ions having m / z values ​​different from those of ions in stability regions R1 and R2.

[0031] By setting the quadrupole RF voltage and quadrupole DC voltage near the apex of the stability region R1 to R3 of a certain m / z, it is possible to transmit only ions having that m / z. Furthermore, the quadrupole RF voltage is scanned so as to pass near the apex of the stability region R1 to R3 of each m / z, as shown by the scan line L1 in FIG. 4 . In this case, by scanning the quadrupole RF voltage while maintaining the relationship between the quadrupole RF voltage and the quadrupole DC voltage, the spectrum 501 shown in FIG. 5 can be obtained. In other words, it is possible to detect ions having each m / z.

[0032] (Calibration Point Correction Process) Next, the calibration point correction process will be described with reference to FIGS. 5 to 7B. FIG. 5 is a graph showing the quadrupole RF voltage-ion signal intensity relationship, which shows the relationship between the quadrupole RF voltage and the ion signal intensity. FIG. 6 is a graph showing the m / z-quadrupole RF voltage relationship, which shows the relationship between the m / z and the quadrupole RF voltage. In FIG. 5, the horizontal axis represents the quadrupole RF voltage, and the vertical axis represents the ion signal intensity. FIG. 5 also shows a spectrum 501 of calibration ions. The calibration ions are ions generated from a calibration sample, and their m / z is known. FIG. 5 also shows a spectrum 502 of impurity ions. The impurity ions are ions derived from impurities due to contamination or the like.

[0033] In the following description, the quadrupole RF voltage refers to the amplitude value of the quadrupole RF voltage, and is a voltage obtained as a result of measuring a plurality of calibration ions with the mass spectrometer 100.

[0034] As shown in FIG. 5, a spectrum 502 of impurity ions is detected in close proximity to a spectrum 501a of calibration ions.

[0035] 5 also shows a scan range 511, which is a voltage range. The scan range 511 is the scan width of the quadrupole RF voltage performed for ion detection. The scan range 511 will be described later.

[0036] Furthermore, a calibration point 521 is plotted in the m / z-quadrupole RF voltage relationship graph shown in Fig. 6. As shown in Fig. 6, the m / z-quadrupole RF voltage relationship graph is a coordinate system having an m / z axis and a quadrupole RF voltage axis as its coordinate axes. In other words, the m / z-quadrupole RF voltage relationship graph is a coordinate system having voltage and m / z as its coordinate axes.

[0037] Calibration points 521 show the relationship between the m / z and the quadrupole RF voltage corresponding to the peak value of the ion signal intensity in spectrum 501 shown in Fig. 5. As described above, the m / z of the calibration ions is known, so it is possible to plot an m / z-quadrupole RF voltage relationship graph such as that shown in Fig. 6. Calibration points 521 are obtained by plotting the voltages obtained as a result of measuring a plurality of calibration ions with mass spectrometer 100 and the m / z of each calibration ion on coordinates.

[0038] As described above, in Fig. 5, the spectrum 502 of the impurity ions is detected near the spectrum 501a of the calibration ions. The peak value of the spectrum 501a is lower than the peak value of the spectrum 502. In Fig. 5, the spectrum 501a and the spectrum 502 are within the same scan range 511. This indicates that the spectrum 501a and the spectrum 502 are detected as a single spectrum 501. This may cause the data processing device 200 to mistake the impurity ions for the calibration ions and make a determination.

[0039] Therefore, as shown in FIG. 6, a calibration point 521b derived from impurity ions is plotted in the vicinity of a calibration point 521a derived from a spectrum 501a.

[0040] As described above, there may be impurity ions having m / z values ​​adjacent to those of the calibration ions. In such cases, as shown in spectra 501a and 502 in FIG. 5 , the peak of the spectrum 501a resulting from the calibration ions is close to the peak of the spectrum 502 resulting from the impurity ions. In this way, the data processing device 200 may confuse the peaks of the calibration ions and the impurity ions. If such a confusion occurs between the peaks of the calibration ions and the impurity ions, the value of the quadrupole RF voltage will differ from the value of the quadrupole RF voltage of the actual calibration ions, as shown in FIG. 6 . In other words, the m / z of the impurity ions will be linked to the quadrupole RF voltage that should be linked to the m / z of the calibration ions that produce spectrum 501a. When measuring a substance with an unknown m / z, the m / z of the measured substance is output based on the m / z-quadrupole RF voltage relationship graph shown in FIG. 6 and the resulting quadrupole RF voltage. However, if the m / z of the contaminant ions is linked to the quadrupole RF voltage to which the m / z of the calibration ions that produce spectrum 501a should be linked, an incorrect m / z will be output.

[0041] The quadrupole DC voltage is determined so that the range of the spectrum 501 due to the calibration ions is a predetermined (constant) value.

[0042] Furthermore, when acquiring spectrum 501, there is a time lag between when ions pass through the quadrupole mass filter 140 and when they are detected by the detector 152. This causes a phenomenon in which the value of the quadrupole RF voltage at the timing when ions are detected by the detector 152 differs from the value of the quadrupole RF voltage at the timing when ions pass through the quadrupole mass filter 140. This causes the m / z of the ions detected to change depending on the scan speed.

[0043] During mass analysis, the quadrupole mass filter 140 operates to selectively transmit ions having a specific m / z while maintaining a fixed quadrupole RF voltage for a certain period of time. To determine the quadrupole RF voltage that will transmit ions having a specific m / z, the measurement processing unit 213 (see FIG. 1 ) rescans the quadrupole RF voltage within a predetermined range and acquires the peak value of the spectrum 501 shown in FIG. 5 . Determining the quadrupole RF voltage corresponding to the m / z of the calibration ions based on this peak value is referred to as voltage calibration. The first scan is performed in the presence of impurity ions, as described below, and the rescan is performed after correction of the calibration point 521 (see FIG. 6 ), as described below.

[0044] To perform voltage calibration with high accuracy, it is desirable to perform mass analysis at a low scan rate. A low scan rate is, for example, 0.1 Da / s to 100 Da / s (1.66 × 10 －２５ g / s~1.66×10 －２２ g / s). On the other hand, at a low scan rate, it takes a long time to acquire the spectrum 501 in a predetermined range. In other words, if the measurement processing unit 213 scans the entire range of the quadrupole RF voltage at a low scan rate, it will take an enormous amount of time. Therefore, there is a disadvantage in that the time required for voltage calibration will also be long.

[0045] Therefore, a spectrum 501 is acquired by scanning only the vicinity of the calibration ions at a low scan rate, as in the scan range 511 shown by the dashed dotted line in Fig. 5. In this way, both the accuracy of voltage calibration and the time required for voltage calibration are often measured.

[0046] Next, the calibration point correction process in this embodiment will be described with reference to FIGS. 7A and 7B. FIGS. 7A and 7B are graphs showing the relationship between m / z and quadrupole RF voltage. FIG. 7A shows an example in which no impurity ions are detected, and FIG. 7B shows an example in which peak confusion occurs due to impurity ions. As shown in FIG. 7A, the m / z of calibration ions that stably pass through the quadrupole mass filter 140 is proportional to the amplitude of the quadrupole RF voltage. Therefore, when no impurity ions are detected, as shown in FIG. 7A, the slope (ai) of the line connecting the calibration points 521 (mi, xi) shown in equation (1) is approximately the same for all calibration points 521. Here, the slope (ai) is the slope between each calibration point 521.

[0047] ai = (xi+1 - xi) / (mi+1 - mi) ... (1)

[0048] where m (i=1, . . . , N) is the m / z value, xi (i, . . . , N) is the value of the quadrupole RF voltage, and i is the number of the calibration point 521.

[0049] In contrast, in FIG. 7B , at (mk, xk), the calibration ion (calibration point 521a) is confused with the adjacent impurity ion (calibration point 521b). As shown in FIGS. 6 and 7B, the calibration point 521b of the impurity ion is plotted as an outlier. Incidentally, (mk, xk) indicates the coordinates of the calibration point 521 in the m / z-quadrupole RF voltage relationship graph. Due to the confusion between the calibration ion and the adjacent impurity ion, the correct calibration point 521a is recognized as the calibration point 521b of the impurity ion, resulting in a shift in the corresponding quadrupole RF voltage. Therefore, the value of the slope (ak-1, ak) changes on both sides of mk, resulting in an increase in the deviation (Di) of ai. The deviation (Di) is defined by the following equation (2). In this way, the deviation (Di) is the deviation with respect to each slope (ai).

[0050] Di = (ai - a_mean) ２ ... (2)

[0051] Here, a_mean is the average of ai defined by the following equation (3). However, the deviation does not have to be the deviation from the average of ai. For example, the deviation (Di) may be defined as Di = ai - ai-1.

[0052]

[0053] 7A, when there is no confusion between impurity ions and calibration ions, the relationship between adjacent calibration points, that is, the value of the slope (ai) (i=1, . . . , N−1) between adjacent calibration points 521, is approximately the same. Utilizing this, in this embodiment, correction is performed for the calibration point 521 whose peak has been mistaken for an impurity ion.

[0054] Specifically, in this embodiment, the correction processing unit 212 (see FIG. 1) determines whether a peak has been confused based on whether the standard deviation (SD) defined by the following formula (4) is equal to or greater than a threshold value (Sth). In other words, whether there is an outlier for each calibration point 521 is determined based on whether the standard deviation (SD) defined by formula (4) is equal to or greater than a threshold value (Sth).

[0055]

[0056] (Flowchart) Figure 8 is a flowchart showing the steps of the mass analysis data processing method according to the first embodiment. Figures 1, 6, etc. are referenced as appropriate. First, the plot processing unit 211 performs a plotting process to plot the measurement results of the calibration ions obtained by the mass spectrometer 100 on an m / z-quadrupole RF voltage relationship graph (S101: first step). At this time, the plotting processing unit 211 performs the plotting based on the quadrupole RF voltage obtained as a result of a scan in the scan range 511 shown in Figure 5 and the m / z of the calibration ions, which is known in advance.

[0057] The correction processing unit 212 then calculates all of the slopes (ai) between the obtained calibration points 521 (S102). The slopes (ai) are calculated according to equation (1). The correction processing unit 212 then calculates the deviation (Di) for each slope (ai) (S103). The deviation (Di) is calculated according to equation (2). Next, the correction processing unit 212 calculates the standard deviation (SD) of the slopes calculated in step S102 (S104). The standard deviation (SD) is calculated according to equation (4). The correction processing unit 212 then determines whether the standard deviation is greater than a preset standard deviation threshold (Sth) (SD > Sth) (S105). In step S105, it is determined whether or not there is an outlier for each calibration point 521. If the standard deviation is equal to or less than the standard deviation threshold (S105 → No), the data processing device 200 ends the processing.

[0058] If the standard deviation is greater than the standard deviation threshold (S105 → Yes), the correction processing unit 212 sets the loop count (h) to "0" (h = 0) (S111). A "Yes" determination in step S105 means that the correction processing unit 212 has determined that an outlier exists for each calibration point 521. In other words, the correction processing unit 212 determines that an outlier exists if the standard deviation (SD) of the deviation (Di) is greater than a preset threshold. Next, the correction processing unit 212 determines whether the loop count (h) is greater than a preset maximum loop count (hmax) (h > hmax) (S112). If the loop count (h) is greater than the maximum loop count (hmax) (S112 → Yes), the correction processing unit 212 outputs an error (S151).

[0059] If the number of loops (h) is equal to or less than the maximum number of loops (hmax) (S112→No), the correction processing unit 212 calculates the deviations (Di) for all the calibration points 521 (S121). The correction processing unit 212 calculates the deviations (Di) according to equation (2).

[0060] The correction processing unit 212 then searches for the deviation (Dmax) having the largest value from among the deviations (Di) (S122), and determines whether the deviation (Dmax) having the largest value is greater than the deviation threshold value (Dth) (S123).

[0061] If the deviation (Dmax) having the largest value is equal to or smaller than the deviation threshold value (Dth) (S123→No), the correction processing unit 212 proceeds to step S141. If the deviation (Dmax) having the largest value is greater than the deviation threshold value (Dth) (S123→Yes), the correction processing unit 212 corrects the calibration point (S124: second step). In this case, the correction processing unit 212 performs the correction by replacing the calibration point 521 corresponding to the deviation (Dmax) having the largest value. The detailed procedure of the correction will be described later. In step S124, the outlier of the calibration point 521 is corrected, and the calibration point 521 is corrected.

[0062] Then, the correction processing unit 212 uses the corrected calibration points 521 to recalculate all of the slopes (ai) between the obtained calibration points 521 (S131). Next, the correction processing unit 212 recalculates the standard deviation (SD) of the slopes calculated in step S131 (S132). Note that, prior to step S132, the same calculation of the deviation (Di) as in step S103A is performed. Then, the correction processing unit 212 determines whether the standard deviation (SD) calculated in step S132 is greater than the standard deviation threshold value (Sth) (SD>Sth) (S133). The standard deviation threshold value (Sth) used in step S133 is the same as that used in step S105.

[0063] If the standard deviation (SD) is greater than the standard deviation threshold value (Sth) (S133→Yes), the correction processing unit 212 increments the loop count (h) by 1 (h++) (S134), and returns the process to step S112.

[0064] If the standard deviation (SD) is equal to or less than the standard deviation threshold value (Sth) (S133 → Yes), the measurement processing unit 213 performs voltage calibration using the corrected calibration point 521 (S141). Thereafter, the correction processing unit 212 returns the process to step S102. However, after step S141 is performed, the process does not necessarily have to return to step S102.

[0065] Specific Example Next, a specific example of the mass spectrometry data processing method shown in FIG. 8 will be described with reference to FIGS. 6 and 8 to 9B. FIG. 9A is a diagram showing a table of specific values ​​of the calibration point 521. The table shown in FIG. 9A has items for the calibration point 521 number, reference m / z, and quadrupole RF voltage. The reference m / z is the m / z of the calibration ion used. The quadrupole RF voltage item also has items for the correct value, the measured value, and the corrected value. The correct value is the quadrupole RF voltage when no confusion between the calibration ions and the impurity ions occurs. The corrected value is the quadrupole RF voltage after the calibration point correction described above has been performed. If the acquired calibration point 521 is correct (no peak confusion occurs), the correct value = the measured value = the corrected value.

[0066] The last row of the table in Fig. 9A shows the standard deviation. The standard deviation is calculated for each of the correct value, the measured value, and the corrected value. Note that the standard deviation shown in Fig. 9A is the standard deviation of the slope between calibration points (a i shown in Equation (1)).

[0067] In the example table shown in FIG. 9A, the correct value differs from the actually measured value at calibration point 251 number "6" because it has been confused with an impurity ion.

[0068] 9B is a graph of the deviation (Di) based on FIG. 9A. In the graph shown in FIG. 9B, the horizontal axis represents the deviation number, and the vertical axis represents the magnitude of the deviation. As shown in the example of FIG. 9A, a mix-up occurred at calibration point number "6" (see FIG. 6), so the deviation between deviation numbers "5" and "6" (i.e., the slopes on both sides of calibration point 521 numbered "6") is large.

[0069] Here, a specific procedure for correcting the calibration point when data of the calibration point 521 as shown in Fig. 9A is obtained is shown. In this embodiment, the correction is performed by linearly correcting the calibration point 521 with a large deviation using the following equation (see Fig. 7B as appropriate).

[0070] First, when the correct quadrupole RF voltage value (x1) is calculated based on the first deviation (D1), the correct quadrupole RF voltage value (x1) is calculated using the following equation (11).

[0071] D1: x1=a2・m1+b2...(11)

[0072] Furthermore, when the correct quadrupole RF voltage value (xN) is calculated based on the Nth (last) deviation (DN), the correct quadrupole RF voltage value (xN) is calculated using the following equation (12).

[0073] DN: xN=aN-1・mN + bN-1...(12)

[0074] If the i-th (i=2 to N−1) deviation Di is greater than the deviation threshold, the correct quadrupole RF voltage value (xi) is calculated using the following equations (13) and (14).

[0075] When Di+1>Di-1: xi+1=ai+2・mi+1+bi+2...(13) When Di+1≦Di-1: xi=ai-1・mi+bi-1...(14)

[0076] In equations (11) to (14), xi and mi (i = 1, ..., N) are shown in Figures 7A and 7B, and ai (i = 1, ..., N) is calculated by equation (1). Furthermore, bi (i = 1, ..., N) is the intercept of the quadrupole RF voltage axis of a line that passes through coordinates (mi, xi) on the m / z-quadrupole RF voltage relationship graph shown in Figures 7A and 7B and has a slope (ai). In this way, the correction processing unit 212 corrects the calibration point 512 based on the slope (ai).

[0077] The processing performed in steps S122 to S141 in Fig. 8 will be specifically described below with reference to Fig. 7A, Fig. 7B, Fig. 9A, and Fig. 9B. Note that in the following description, the step numbers refer to the step numbers of the processing shown in Fig. 8.

[0078] As described above, the operation when a peak is confused at calibration point 521 (m / z: 1172.145) of number "6" in FIG. 9A will be described below as an example. At number "6" in FIG. 9A, the unified atomic mass unit is about 1.0 Da (1.66×10 －２４ g) The peaks are confused with those of high-value contaminant ions.

[0079] (S122) The correction processing unit 212 searches for the deviation (Di) with the largest value from among all the deviations. Here, i is the deviation number shown in FIG. 9B. In the example shown in FIG. 9B, D5 (i=5) = 0.186, indicated by reference numeral 601, is the largest. (S123) The correction processing unit 212 determines whether the deviation value searched for in step S122 is equal to or greater than the deviation threshold value (Dth). It is assumed that D5 (reference numeral 601) shown in FIG. 9B is equal to or greater than the deviation threshold value.

[0080] (S124) The correction processing unit 212 corrects the calibration point 521 by replacing the calibration point 521 corresponding to the deviation (Dmax) having the largest value. Specifically, the correction processing unit 212 replaces the quadrupole RF voltage (xi or xi+1) of the calibration point 521 (mi or mi+1) having the slope (ai) corresponding to the maximum deviation (Di) with a value corrected from the previous or next calibration point 521. The replacement is performed by the quadrupole RF voltage calculated according to equations (11) to (14).

[0081] 9B, D5=0.186 is the maximum deviation, and D6>D4, so the correction processing unit 212 replaces the quadrupole RF voltage (xi+1) of the calibration point 521 numbered "6" with the value calculated by xi+1=ai+2·mi+1+bi+2 (Equation (13)). As a result, as shown in FIG. 9A, the quadrupole RF voltage of the calibration point 521 numbered "6" is corrected to "111958".

[0082] (S131) ​​The correction processing unit 212 recalculates the slope (ai) using the quadrupole RF voltage corrected in step S124. (S132) The correction processing unit 212 recalculates the standard deviation (SD) of the slope recalculated in step S131. In the example shown in FIG. 9A, the standard deviation (SD) after correction is "0.099".

[0083] (S133) The correction processing unit 212 compares the corrected standard deviation with the standard deviation threshold value (Sth). In the example shown in Fig. 9A, the corrected standard deviation (SD) is "0.099" as described above, which is less than the standard deviation threshold value (Sth = 0.1714).

[0084] If the corrected standard deviation is equal to or less than the threshold value in step S133 (S133→No), the measurement processor 213 performs the process of step S141. In step S141, the measurement processor 213 performs voltage calibration for the corrected calibration point 521, using the corrected quadrupole RF voltage as an initial value (third step). Specifically, the measurement processor 213 performs the above-mentioned scan using the corrected quadrupole RF voltage as the initial value to reacquire the spectrum 501. Then, based on the reacquired spectrum 501, the measurement processor 213 estimates, by correction, the quadrupole RF voltage corresponding to the peak value of the calibration ions shown in spectrum 501a. In this way, the correct quadrupole RF voltage can be acquired. The process performed in step S141 will be described later.

[0085] Furthermore, in step S133, if the corrected standard deviation is greater than the threshold value (S133→Yes), the correction processing unit 212 repeats the processes from step S112 onwards until the standard deviation becomes equal to or less than the threshold value. However, if the number of loops exceeds a predetermined number (hmax), the correction processing unit 212 outputs an error (S151).

[0086] 9A, for the calibration point 521 numbered "6," the corrected quadrupole RF voltage is "111958" (V) as described above. The difference between this quadrupole RF voltage and the correct quadrupole RF voltage "111977" (V) is only 19 (V) (= approximately 0.2 Da (0.332 × 10 －２４g). As a result, in voltage calibration using the corrected quadrupole RF voltage as the initial value, it is possible to obtain the peak value derived from the correct calibration ions, as described above. Furthermore, as shown by the dashed line and open circles in FIG. 9B, the deviation is also small.

[0087] In equation (1), which shows the gradient between calibration points, the smaller the m / z difference (mi+1 - mi), the more sensitively the deviation in the amplitude of the quadrupole RF voltage is reflected. Calibration samples are often selected so that the calibration points 521 have uniform m / z intervals. However, there are cases where calibration samples are selected with non-uniform m / z intervals. In this way, when the m / z intervals of the calibration points 521 are not uniform, the m / z difference (mi+1 - mi) between the calibration points may be weighted when calculating the standard deviation.

[0088] In addition, in this embodiment, the voltage calibration (S141 in FIG. 8) is performed after the correction of the calibration point 521, but this is not limiting. After the correction of the calibration point 521 is performed, only the correction result (i.e., the quadrupole RF voltage after correction) is stored in the storage unit 220, and the voltage calibration may be performed as a process separate from the correction of the calibration point 521.

[0089] (Voltage Calibration) FIG. 10 is a diagram showing a voltage calibration technique. FIG. 1 is referred to as appropriate. FIG. 10 is an enlarged view of the spectrum 501a and the vicinity of the spectrum 502 in the quadrupole RF voltage-ion signal intensity relationship graph shown in FIG. 5. The process shown in FIG. 10 is performed by the measurement processing unit 213 shown in FIG. 1 in step S141 of FIG. 8. In voltage calibration after the calibration point 521 has been corrected, measurement is started in a narrow scan range 511a centered on the quadrupole RF voltage (reference numeral 531) calculated using the corrected calibration point 521. That is, the scan range 511 is gradually widened from the narrow scan range 511a, such as the scan range 511a, centered on the quadrupole RF voltage (reference numeral 531) estimated by correcting the calibration point 521. Note that number "6" in Fig. 9A indicates that the difference between the quadrupole RF voltage obtained by correcting the calibration point 521 and the correct quadrupole RF voltage "111977" (V) is only 19 (V). In other words, the quadrupole RF voltage estimated by correcting the calibration point 521 is not necessarily the true center of the spectrum 501a that is the target of voltage calibration. For this reason, in Fig. 10, the quadrupole RF voltage (reference numeral 531) calculated using the corrected calibration point 521 is shown at a position shifted from the center of the spectrum 501a.

[0090] The scan range 551 is changed each time a measurement is performed. That is, the scan range 511 is gradually widened from the scan range 511a to the scan range 511c. The scan range 511 is then gradually widened until the calibration ion spectrum 501a falls within the scan range 511c. By starting the measurement from the narrow scan range 511 in this way, it is possible to prevent the spectrum 502a from being scanned. This makes it possible to prevent the peak of the spectrum 501a from being confused with the peak of the spectrum 502 due to the adjacent impurity ion. It is also possible to obtain the true center of the spectrum 501a.

[0091] In this manner, in voltage calibration, the measurement processing unit 213 measures the calibration ions in the mass spectrometer 100 (see FIG. 10 ) in a scan range 511 centered on the quadrupole RF voltage calculated using the corrected calibration point 521. At this time, the measurement processing unit 213 changes the scan range 511 so that it gradually becomes wider each time a measurement is performed, as shown by scan ranges 511 a to 511 c in FIG. 10 .

[0092] 10 is performed even though the quadrupole EF voltage corresponding to the peak value of spectrum 501a is estimated by calibration point 521. This is because, as described above, the quadrupole RF voltage value estimated by correction does not necessarily indicate the correct value, as indicated by the number "6" of calibration point 521 in FIG.

[0093] According to the first embodiment, when performing voltage calibration, even if there is an impurity ion having an m / z adjacent to the calibration point 521, it is possible to correct the peak confusion between the impurity ion and the calibration ion. This makes it possible to determine an accurate quadrupole RF voltage derived from the calibration ion. As a result, when performing mass analysis of an unknown substance, highly accurate mass analysis is possible. Furthermore, according to the first embodiment, correction of the calibration point 521 and voltage calibration can be performed even if there is only one peak confusion.

[0094] Second Embodiment A second embodiment will be described below. The configuration of the mass spectrometry system 1 in the second embodiment is the same as the configuration shown in Fig. 1, and therefore will not be illustrated or described in the second embodiment. In Fig. 12, the same components as those in Fig. 7B are assigned the same reference numerals, and their description will be omitted.

[0095] The processing performed in the second embodiment will be described below with reference to FIGS. 11 and 12 . FIG. 11 is a flowchart showing the procedure of the mass spectrometry data processing method according to the second embodiment. FIG. 12 is a graph showing the relationship between m / z and quadrupole RF voltage. In the following description, step numbers are those shown in FIG. 11 . In addition, steps in FIG. 11 that are the same as those in FIG. 8 are assigned the same step numbers, and descriptions thereof will be omitted as appropriate. In the second embodiment, the correction processing unit 212 calculates the slope and intercept 711 by applying the least squares method to each of the calibration points 521. Then, the correction processing unit 212 compares the standard deviation and a threshold value based on the calculated slope. That is, in the first embodiment, the slope (ak) between the calibration points 521 was calculated one by one in steps S102 and S131 of FIG. 8 . In contrast, in the second embodiment, the correction processing unit 212 uses the least squares method according to the following equation (21) to find a straight line 701 that is close to all of the calibration points 521, as shown in FIG. 12 . That is, the correction processing unit 212 calculates the slope and intercept 711 of the straight line 701 by applying the least squares method to each of the calibration points 521 (S102A and S131A). That is, the straight line 701 has a slope and intercept 711 calculated by applying the least squares method to each of the calibration points 521. In this way, in the second embodiment, the slopes between the respective calibration points 521 are unified to the slope calculated by the least squares method.

[0096] Next, the correction processing unit 212 calculates the deviation (Di) (S103A). In the second embodiment, the deviation (Di) is defined as the length of a perpendicular line 721 from each calibration point 521 to a straight line 701 obtained by the least squares method. The length of the perpendicular line 721 is the distance from the straight line 701 having a slope and an intercept 711 for each calibration point 521. In this way, in step S103A, the correction processing unit 212 calculates the distance (length of the perpendicular line 721) from the straight line 701 having a slope and an intercept 711 for each calibration point 512 as the deviation (Di).

[0097] Thereafter, the correction processing unit 212 calculates the standard deviation (SD) of the deviation (Di) calculated in step S103A (S104A).

[0098] If the standard deviation (SD) of the deviation (Di) is greater than a preset threshold (SD>Sth) (S105→Yes), the correction processing unit 212 corrects the calibration points 521 based on the slope. The procedure for correcting the calibration points 521 based on the slope is the same as in the first embodiment.

[0099]

[0100] In equation (21), "slope" indicates the slope, and mi and xi indicate m / z and quadrupole RF voltage as shown in Figures 7A and 7B. Furthermore, the variable with a bar above m indicates the average of mi. Furthermore, the variable with a bar above x indicates the average of xi (quadrupole RF voltage).

[0101] The calibration point 521 is corrected by the following equation (22).

[0102] xi_cor=slope・mi+b...(22)

[0103] In equation (22), xi_cor represents the value of the corrected quadrupole RF voltage, and b represents the intercept 711 of the quadrupole RF voltage axis calculated by the least squares method. That is, the corrected calibration point 521 is corrected so as to lie on the straight line 701 calculated by the least squares method.

[0104] In step S121A of Fig. 11, the deviation (Di) is calculated using the same procedure as in step S103A. Also, although not shown in Fig. 11, before step S121A, the slope and intercept 711 are calculated using the same procedure as in step S102A. Also, step S131A is the same process as step S102A, and step S132A is the same process as step S104A. Furthermore, although not shown, the same process as in step S103A is performed between step S131A and step S132A.

[0105] In this way, in the second embodiment, the misidentification of the peaks of the impurity ions and the calibration ions is corrected based on the gradient calculated by using the least squares method for the calibration point 521 .

[0106] In the method shown in the second embodiment, the slope between the calibration points 521 is calculated at once by the least squares method, as opposed to the first embodiment in which the slope between the calibration points 521 is calculated one by one. Therefore, the method shown in the second embodiment requires simpler calculations than the method shown in the first embodiment, and can be performed at high speed.

[0107] Third Embodiment Next, referring to FIG. 13 , an example will be shown in which the calibration point correction process shown in the first and second embodiments is applied to a mass spectrometry system 1a in which a time-of-flight mass spectrometer 400 is installed in the analysis unit 103. FIG. 13 is a diagram showing an example of the configuration of a mass spectrometry system 1a according to the third embodiment. The mass spectrometry system 100a shown in FIG. 13 is similar to the mass spectrometry system 1 shown in FIG. 1 in the following respects: (A1) The time-of-flight mass spectrometer 400 is installed in the analysis unit 103. (A2) A power supply 410 that applies a pulse voltage is connected to a pusher electrode 401 that constitutes the time-of-flight mass spectrometer 400. This power supply 410 is controlled by a voltage control device 300. In FIG. 13 , components that are similar to those in FIG. 1 are designated by the same reference numerals.

[0108] In the mass spectrometer 100a, ions generated in an ion source 151 are introduced into a first differential pumping unit 101 through an aperture 121, as in FIG. 1 . Similarly to FIG. 1 , the first differential pumping unit 101 is evacuated by a pump 111. This maintains the first differential pumping unit 101 at a vacuum level of 10 Pa to 500 Pa. Ions that pass through the first differential pumping unit 101 are introduced into a second differential pumping unit 102 through an aperture 122. Similarly to FIG. 1 , the second differential pumping unit 102 is evacuated by a pump 112. This maintains the second differential pumping unit 102 at a vacuum level of 0.1 Pa to 10 Pa. Similarly to FIG. 1 , an ion guide 130 that focuses ions is installed in the second differential pumping unit 102. The ions focused by the ion guide 130 pass through an aperture 123 and are introduced into an analyzer 103 in which a time-of-flight mass spectrometer 400 is installed. 1, the analytical section 103 is evacuated by a pump 113. This allows the analytical section 103 to be maintained at a pressure of 1E-5 Pa or less.

[0109] The time-of-flight mass spectrometer 400 is composed of a pusher electrode 401, an acceleration electrode 402, a reflector electrode 403, and a detector 152. A pulse voltage is applied to the pusher electrode 401 by a power supply 410. When this pulse voltage is applied, the pusher electrode 401 bends the direction of travel of some of the ions incident from the ion guide 130 to a direction perpendicular to the direction of the ions' incidence. The bent ions then head toward the acceleration electrode 402. The ions whose direction of travel has been bent are accelerated by the acceleration electrode 402 and reflected by the reflector electrode 403 (shown by the open arrow in FIG. 13 ). The ions reflected by the reflector electrode 403 are detected by the detector 152. The time it takes for an ion bent by the pusher electrode 401 to reach the detector 152, i.e., the time of flight of the ion, depends on the m / z of the ion. Therefore, an ion spectrum 501 (see FIG. 5 ) can be obtained by plotting the time of flight and the signal intensity of the ion detected by the detector 152.

[0110] In the time-of-flight mass spectrometer 400, a multichannel plate type detector 152 is generally used as the detector 152. The detector 152 converts the detection intensity of ions into an electrical signal (output signal) and sends it to the data processing device 200. At this time, as in FIG. 1, the output signal output from the detector 152 is converted into digital data at a fixed sampling period and then sent to the data processing device 200. As in FIG. 1, the conversion to digital data is performed by an analog-to-digital converter (ADC) not shown or a pulse counting unit not shown. The data processing device 200 stores the sent digital data in the memory unit 220.

[0111] In the mass spectrometry system 1a shown in FIG. 13 , calibration ions can also be measured, and the techniques shown in the first and second embodiments can be applied to the obtained spectrum 501 (see FIG. 5 ). In this case, the amplitude of the pulse voltage applied to the pusher electrode 401 is used instead of the quadrupole RF voltage of the first embodiment. That is, in the third embodiment, the pulse voltage is a voltage obtained as a result of measuring a plurality of calibration ions with the mass spectrometer 100. Furthermore, in the third embodiment, the quadrupole RF voltage axis of the m / z-quadrupole RF voltage relationship graphs shown in FIGS. 6 to 7B becomes the pulse voltage axis.

[0112] In the mass spectrometry system 1a, if there are impurity ions whose m / z values ​​are adjacent to the calibration point 521, the peak of the impurity ions may be confused with the peak of the calibration ions. However, by using a pulse voltage instead of the quadrupole RF voltage of the first embodiment, it is possible to perform processing similar to that of the first and second embodiments. This makes it possible to correct the peak confusion. This makes it possible to obtain an accurate m / z value when performing mass analysis on an unknown substance.

[0113] The present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those having all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0114] Furthermore, some or all of the above-described components, functions, plot processing unit 211, correction processing unit 212, measurement processing unit 213, storage unit 220, etc. may be implemented in hardware, for example, by designing them as integrated circuits. Furthermore, as shown in FIG. 2 , the above-described components, functions, etc. may be implemented in software by a processor such as a CPU interpreting and executing programs that implement the respective functions. Information such as programs, tables, and files that implement the respective functions may be stored in a memory, a recording device such as an SSD (Solid State Drive), or a recording medium such as an IC (Integrated Circuit) card, an SD (Secure Digital) card, or a DVD (Digital Versatile Disc).

[0115] In addition, in each embodiment, the control lines and information lines shown are those that are considered necessary for explanation, and not all control lines and information lines in the product are necessarily shown. In reality, it can be considered that almost all components are interconnected.

[0116] 1, 1a Mass spectrometry system 100, 100a Mass spectrometer 140 Quadrupole mass filter 141, 141a to 141d Quadrupole rod electrodes 152 Detector 200 Data processing device 211 Plot processing unit 212 Correction processing unit 213 Measurement processing unit 400 Time-of-flight mass spectrometer 501 Spectrum 501a Spectrum 502 Spectrum 511, 511a to 511c Scan range (voltage range) 521 Calibration point 521a Calibration point (calibration point using calibration ions) 521b Calibration point (outlier) 701 Straight line (including slope) 711 Intercept 721 Perpendicular line (deviation) S101 Plotting process (first step) S124 Correction (second step) S141 Mass calibration (third step)

Claims

1. A data processing device having: a plot processing unit that plots, as calibration points, a voltage obtained as a result of measuring a plurality of calibration ions with known m / z using a mass spectrometer, and the m / z of each calibration ion on a coordinate system having the voltage and the m / z as coordinate axes; and a correction processing unit that, if there is an outlier for each of the calibration points, corrects the outlier, thereby correcting the calibration points.

2. The data processing device according to claim 1, further comprising a measurement processing unit which measures the calibration ions by the mass spectrometer within a voltage range centered on the voltage calculated based on the corrected calibration point.

3. The data processing device according to claim 2, characterized in that the measurement processing unit changes the voltage range so that the voltage range becomes gradually wider each time the measurement is performed.

4. The data processing device according to claim 1, characterized in that the correction processing unit calculates the slope between each of the calibration points, calculates the deviation related to each of the slopes, and if the standard deviation of the deviations is greater than a preset threshold value, determines that an outlier is present, and corrects the calibration points based on the slopes.

5. The data processing device according to claim 1, characterized in that the correction processing unit calculates a slope and an intercept by applying the least squares method to each of the calibration points, calculates a deviation between each of the calibration points and a straight line having the slope and the intercept, and corrects the calibration points based on the slope if the standard deviation of the deviation is greater than a preset threshold value.

6. A mass spectrometry system comprising: a mass spectrometer; a plotting processing unit that plots, as calibration points, a voltage obtained as a result of measuring a plurality of calibration ions with known m / z using the mass spectrometer and the m / z of each calibration ion on a coordinate system having the voltage and the m / z as coordinate axes; and a correction processing unit that, if there is an outlier for each of the calibration points, corrects the outlier, thereby correcting the calibration points.

7. The mass spectrometry system according to claim 6, further comprising a measurement processing unit which measures the calibration ions by the mass spectrometer within a voltage range centered on the voltage calculated by the corrected calibration point.

8. The mass spectrometry system according to claim 6, characterized in that the mass spectrometry device has an analysis section which is a quadrupole mass filter or a time-of-flight mass spectrometry device.

9. A mass spectrometry data processing method, comprising: a data processing device that executes a first step of plotting, as calibration points, the voltage obtained as a result of measuring a plurality of calibration ions, each having a known m / z, with a mass spectrometer, and the m / z of each calibration ion on a coordinate system having the voltage and the m / z as coordinate axes; and a second step of correcting, if there is an outlier for each of the calibration points, correcting the calibration points by correcting the outlier.

10. The method for processing mass spectrometry data according to claim 9, further comprising the step of: performing a third step of measuring the calibration ions by the mass spectrometer within a voltage range centered on the voltage calculated by the corrected calibration point.

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