JP2016053500A - Chromatograph mass spectrometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the following problem: there have been needs to reduce the number of compounds to be measured simultaneously in parallel or to divide a measurement process into a plurality of runs if detection sensitivity is insufficient for certain compounds in a multicomponent simultaneous analysis using MRM measurement.SOLUTION: A plurality of ions in a measurement time range are each subjected to MRM measurement in the same dwell time to determine an SN ratio at the peak on a mass chromatogram for each ion. The cycle time is distributed according to the proportion of the SN ratios to determine the optimum value of the dwell time of each ion such that the SN ratio for each ion in one measurement time range, or the detection sensitivity, becomes equal to one another. As a result, the dwell time for ions having inherently higher detection sensitivity becomes shorter, and the dwell time for ions having lower detection sensitivity becomes longer. Measurement is performed for a standard sample under the condition of the dwell times thus determined to prepare a calibration curve, and measurement results of an unknown sample are checked against the calibration curve to calculate the quantitative value.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a chromatograph mass spectrometer that combines a chromatograph such as a gas chromatograph or a liquid chromatograph and a mass spectrometer, and particularly uses a tandem quadrupole mass spectrometer capable of performing MS / MS analysis. The present invention relates to a chromatograph mass spectrometer suitable for a chromatograph tandem quadrupole mass spectrometer.

  In order to identify a substance having a large molecular weight and analyze its structure, a technique called MS / MS analysis (tandem analysis) is widely used as one technique of mass spectrometry. There are various types of mass spectrometers for performing MS / MS analysis, but the tandem quadrupole type (triple quadrupole type, which is relatively simple in structure and easy to operate and handle, Mass spectrometer (also called triple quadrupole type). A general tandem quadrupole mass spectrometer is equipped with a quadrupole mass filter at the front and rear stages of a collision cell that cleaves ions by collision-induced dissociation (CID). The precursor ions having a specific mass-to-charge ratio selected by the above are cleaved in the collision cell, and the product ions generated thereby are separated and detected by the subsequent quadrupole mass filter according to the mass-to-charge ratio.

  In recent years, when analyzing a complex sample containing a plurality of target compounds, a gas chromatograph (GC) or liquid chromatograph (LC) that temporally separates the compounds in the sample, and the tandem quadrupole mass described above. A gas chromatograph mass spectrometer (hereinafter sometimes abbreviated as “GC / MS / MS”) or a liquid chromatograph mass spectrometer (hereinafter abbreviated as “LC / MS / MS”) combined with an analyzer. ) Is frequently used. Especially for quantification of compounds in samples containing many compounds or complex samples containing many contaminated components, such as multi-component simultaneous analysis of pesticide residues, multi-component simultaneous analysis of fragrances, or multi-component simultaneous analysis of veterinary drugs. GC / MS / MS and LC / MS / MS are essential.

  For example, in analysis such as multi-component simultaneous analysis of residual agricultural chemicals in foods, the target compound (target compound) is determined in advance, and it is important how sensitive the target compound can be detected. For this purpose, the tandem quadrupole mass spectrometer is sometimes called MRM (Multiple Reaction Monitering, SRM = Selected Reaction Monitoring) that fixes the mass-to-charge ratio of the precursor ion and the mass-to-charge ratio of the product ion. ) Measurement is generally used. This is because the MRM measurement can achieve high selectivity by eliminating the influence of contaminating components.

  In the MRM measurement in GC / MS / MS or LC / MS / MS, a combination of the mass-to-charge ratio m1 of the precursor ion corresponding to the compound and the mass-to-charge ratio m2 of the product ion in advance near the retention time of the target compound, That is, the transition is set as one of the measurement conditions. For example, if the retention time of the target compound is t1, the transition (m1 →) corresponding to the compound within the measurement time range of t1−Δt to t1 + Δt in which an appropriate margin ± Δt is set before and after the retention time t1. Set m2). In order to identify an unintended overlap of impurities, in many cases, not only one but a plurality of transitions are set for one compound.

  In the case of the multi-component simultaneous analysis as described above, since the number of target compounds is large, the time ranges in which a plurality of target compounds are eluted from the column often overlap. Therefore, it is necessary to perform MS / MS measurement while switching a large number of transitions within a certain measurement time range. For example, if three target compounds overlap in a certain measurement time range, and MRM measurement is performed with two different transitions for each target compound, 3 × 2 = 6 transitions in that measurement time range. Switching is necessary.

  When performing multi-component simultaneous analysis in the MRM measurement mode, quantification is performed based on the area of the peak appearing in the mass chromatogram (extracted ion chromatogram). In order to sufficiently reproduce the shape of this peak, at least 10 to 12 (about 20 if possible) data points (sampling points) are required for each peak. Now, assuming that the peak appearance time is 6 seconds and there are 20 data points, it is necessary to sample data every 0.3 seconds. As described above, if it is necessary to switch six transitions, the sampling time for each transition is 0.3 / 6 = 0.05 seconds. This time is a parameter called dwell time.

  FIG. 3 is a schematic diagram showing peaks on a chromatogram (mass chromatogram or total ion chromatogram), data points on the peak, and the relationship between one cycle time and dwell time between adjacent data points. is there. In this figure, each of ions [n] (where n = 1 to 6) shows one transition. However, here, in order to simplify the explanation, the time (settling time) required for voltage stabilization or the like that is normally required at the time of transition switching is ignored. Also, the number of data points for one peak is less than the value described above.

  The dwell time depends on the number of transitions to be detected in parallel (6 in this example). Therefore, if the cycle time is the same, the dwell time becomes shorter as the number of transitions to be detected in parallel increases. Further, if the number of transitions is increased while keeping the dwell time constant, the cycle time becomes longer and the number of data points for one peak is reduced.

  As described in Patent Document 1 and the like, the dwell time in MRM measurement is a time for capturing signal intensity data obtained by an ion detector in a certain transition. Therefore, as the dwell time is shortened, the detection sensitivity is lowered, and the quantitative accuracy is also lowered. Therefore, conventionally, in order to avoid excessively low detection sensitivity, if the number of transitions set within the measurement time range is large and the dwell time falls below a predetermined threshold, the compound to be measured at one time is retained. Adjustment is performed so as to reduce the number of transitions detected in parallel by dividing the measurement time range so that the measurement times of the groups do not overlap with each other. In the case of multi-component simultaneous analysis, the required detection sensitivity is often different for each compound, and even with the same concentration of compound, the detection sensitivity differs depending on the transition. A second measurement may be made only for compounds that do not reach the required sensitivity level.

International Publication No. 2013/153647 International Publication No. 2014/049823

  However, depending on the type and number of compounds contained in the sample, it may be difficult to divide the target compound into a plurality of groups so that the measurement time ranges of each group do not overlap. A large number of compounds cannot be analyzed simultaneously by measurement alone, and it is necessary to divide the measurement twice or more. In this case, not only a long measurement time is required, but also a large amount of sample is required.

  On the other hand, in order to analyze a large number of compounds in a single measurement while ensuring a somewhat long dwell time, it is necessary to lengthen the cycle time or narrow the measurement time range of each compound. However, there is a problem that the number of data points constituting one peak is small, the peak top cannot be properly captured, and the approximation of the shape of the peak rising and falling curves is deteriorated. In the latter case, even if the peak top can be captured, there is a possibility that the bottom of the peak may be lost, and in any case, the accuracy of the peak area is reduced, leading to a decrease in quantitativeness.

  The present invention has been made to solve these problems, and the object of the present invention is to satisfy the detection sensitivity required for each compound as much as possible when analyzing a plurality of compounds. It is an object of the present invention to provide a chromatographic mass spectrometer capable of simultaneously analyzing the above compounds.

  In conventional chromatographic mass spectrometers, it is assumed that the dwell time for a plurality of ions detected simultaneously in parallel when performing MRM measurement on a plurality of compounds is the same. The dwell time was only adjusted according to the number of transitions. On the other hand, in the chromatograph mass spectrometer according to the present invention, the dwell times for a plurality of ions detected in parallel can be different, and the preliminary measurement performed under the same dwell time conditions. Based on this result, the dwell time is adjusted for each ion, so that the detection sensitivities for a plurality of ions are made uniform or the required detection sensitivities are satisfied.

That is, in order to solve the above problems, the present invention provides a chromatograph that separates a plurality of compounds in a sample in a time direction and ions derived from the compounds separated by the chromatograph according to a mass-to-charge ratio. A mass analysis unit that detects and separates, and the mass analysis unit performs multiple reaction monitoring (MRM) measurement or selection for a plurality of ions derived from one or a plurality of compounds within a specified measurement time range. In a chromatograph mass spectrometer capable of performing a measurement mode in which ion monitoring (SIM) measurement is sequentially repeated,
a) A dwell time which is a data acquisition time for one ion in a cycle time which is one measurement period when MRM measurement or SIM measurement for a plurality of designated ions is sequentially repeated within a designated measurement time range. By performing a preliminary measurement on a predetermined sample under conditions set identically for all of the specified plurality of ions, the intensity signals of the plurality of ions in the specified measurement time range are obtained. A preliminary measurement control unit for controlling each part of the apparatus so as to obtain each;
b) An index for calculating an index value reflecting the detection sensitivity of each of the ions based on the intensity signals of the plurality of ions in the specified measurement time range acquired under the control of the preliminary measurement control unit A value calculator,
c) Based on the index value for each ion calculated by the index value calculation unit, the dwell time of each ion in the specified measurement time range is determined so that the detection sensitivity of each ion is in a predetermined state. A dwell time determination unit to
It is characterized by having.

  In the chromatograph mass spectrometer according to the present invention, the chromatograph is typically a gas chromatograph or a liquid chromatograph. Further, the mass spectrometer is typically a single type quadrupole mass spectrometer or a tandem quadrupole mass spectrometer capable of MS / MS analysis.

  For example, the measurement conditions have been set so that MRM measurement is performed on a plurality of ions derived from a plurality of compounds in a certain measurement time range in which a plurality of compounds may be eluted from the chromatographic column. Shall. If the cycle time is specified at the same time, the dwell time per transition can be obtained by dividing the cycle time by the number of transitions. This is a value obtained on the premise that the dwell times for a plurality of transitions are the same as in the past. The preliminary measurement control unit performs preliminary measurement on a predetermined sample containing the compound by controlling each part of the apparatus using the dwell time thus obtained as a parameter. By the measurement, intensity signals of a plurality of ions in the designated measurement time range are obtained.

  Based on the intensity signals of the plurality of ions, the index value calculation unit calculates an index value reflecting the detection sensitivity of each ion by a predetermined method. For example, a mass chromatogram at each mass-to-charge ratio can be created based on the ion intensity signal obtained by MRM measurement. Since the peak corresponding to the compound appears in the chromatogram, it is calculated in the chromatogram. The S / N ratio and the peak area or height on the chromatogram can be used as index values. Various known methods can be used for the calculation of the S / N ratio. For example, the noise level (N) is determined from the change in the signal (baseline) where no peak exists on the chromatogram, and the signal at the peak top is determined. The S / N ratio may be calculated with S as the intensity.

  The dwell time determination unit determines the dwell time of each ion so that the detection sensitivity of each ion is in a predetermined state, for example, approximately the same, based on an index value such as an S / N ratio calculated for each ion, that is, for each transition. Decide each. For example, the SN ratio, peak area value, and the like substantially correspond to the detection sensitivity. Therefore, in order to make the detection sensitivity substantially uniform, the dwell time of each ion may be adjusted so that the dwell time is shortened as the SN ratio is increased. . In addition, when the detection sensitivity required for each compound or ion is different, for example, after adjusting the dwell time so that the detection sensitivities are almost uniform, a coefficient corresponding to the required detection sensitivity ratio is multiplied. It is only necessary to determine the dwell time of each ion by correcting the above.

  When the cycle time is specified in advance, the total dwell time for each ion needs to be within the cycle time. Therefore, the dwell time determination unit, based on the index value for each ion, divides the given cycle time and assigns it to each ion so that the dwell time is shorter as the index value is larger. What is necessary is just to determine the dwell time of ion, respectively.

Of course, when the dwell time is changed, the ionic strength signal obtained by measuring a certain concentration of compound changes, so that the dwell time for each ion is determined first, and then the compound is quantified. It is necessary to obtain a calibration curve.
Therefore, in the chromatograph mass spectrometer according to the present invention, preferably, calibration of one or a plurality of compounds corresponding to the specified plurality of ions under the dwell time condition determined by the dwell time determination unit. Measurement for preparing a line and measurement of a sample for compound quantification using the calibration curve may be performed.

  According to the chromatograph mass spectrometer according to the present invention, when analyzing a plurality of compounds in parallel by MRM measurement or SIM measurement in the mass spectrometer, the concentration is the same because, for example, ionization efficiency differs depending on the compound. Even when there is a difference in the ionic strength signals, the detection sensitivity of the multiple compounds is almost the same, or each compound meets the required detection sensitivity. can do. As a result, it is possible to analyze many compounds at once while ensuring the necessary and sufficient quantitative accuracy. For example, in the past, a sample that had to be analyzed in a plurality of times was once. This will be enough for analysis. Alternatively, the cycle time can be shortened compared to the conventional method, or the measurement time range can be expanded by increasing the number of compounds to be measured within one measurement time range. It is possible to accurately capture, and the quantitative accuracy can be improved.

The block diagram of the principal part of GC / MS / MS by one Example of this invention. Explanatory drawing of the dwell time automatic setting process in GC / MS / MS of a present Example. Schematic which shows the peak on the chromatogram in conventional GC / MS / MS, the data point on a peak, and the relationship between one cycle time and dwell time between adjacent data points.

  Hereinafter, a gas chromatograph tandem quadrupole mass spectrometer (GC / MS / MS) which is an embodiment of a chromatograph mass spectrometer according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a configuration diagram of a main part of the GC / MS / MS of this embodiment.

The GC / MS / MS of the present embodiment includes a gas chromatograph (GC) unit 1 and a mass analysis unit 2 that is a tandem quadrupole mass spectrometer in order to perform analysis on a sample and collect data. Is provided.
In the GC unit 1, a carrier gas such as helium is supplied to the column 12 through the sample vaporizing chamber 10 at a constant flow rate. The column 12 is built in the column oven 11 and is temperature-controlled so as to be maintained at a constant temperature or according to a predetermined temperature profile. When a small amount of sample liquid is injected into the sample vaporizing chamber 10 at a predetermined timing, the sample liquid is vaporized in a short time and is introduced into the column 12 along with a carrier gas flow. And while passing through the column 12, various compounds contained in the sample are separated and flow out from the outlet of the column 12 with a time lag.

  The mass analyzer 2 includes a collision cell 23 in which an ion source 21 by an electron ionization (EI) method, a front quadrupole mass filter 22 and a multipole ion guide 24 are housed inside a vacuum chamber 20 that is evacuated. A post-stage quadrupole mass filter 25 and an ion detector 26. As the ion detector 26, for example, a combination of a conversion dynode and an electron multiplier is used.

  When performing MS / MS analysis, collision-induced dissociation (CID) gas is supplied into the collision cell 23. The sample gas flowing out from the outlet of the column 12 of the GC unit 1 is introduced into the ion source 21, and the compound molecules in the sample gas are ionized. A predetermined voltage is applied to the four rod electrodes constituting the front-stage quadrupole mass filter 22, and among the various ions generated by the ion source 21, only ions having a specific mass-to-charge ratio corresponding to the voltage are used. Passes through the front quadrupole mass filter 22 and is introduced into the collision cell 23. The ions come into contact with the CID gas in the collision cell 23 to promote dissociation, and various product ions are generated. A predetermined voltage is also applied to the four rod electrodes constituting the latter-stage quadrupole mass filter 25, and only product ions having a specific mass-to-charge ratio corresponding to the voltage pass through the latter-stage quadrupole mass filter 25, The ion detector 26 is reached.

The ion detector 26 outputs a detection signal (ion intensity signal) corresponding to the amount of ions that have reached, and this detection signal is converted into digital data by an A / D converter (ADC) 27 and input to the data processing unit 3. Is done.
The data processing unit 3 includes a data collection unit 31, a mass chromatogram creation unit 32, a peak detection unit 33, an SN ratio calculation unit 34, an optimum dwell time calculation unit 35, and the like as functional blocks. Each part of the GC unit 1 and the mass analysis unit 2 is controlled by an analysis control unit 4 including a measurement condition setting unit 41. Operations of the analysis control unit 4 and the data processing unit 3 are comprehensively controlled by the central control unit 5. An input unit 6 and a display unit 7 are connected to the central control unit 5 as a user interface.
All or part of the data processing unit 3, the analysis control unit 4, and the central control unit 5 use a personal computer as a hardware resource and execute dedicated control / processing software installed in the computer in advance. Thus, each function can be realized.

When simultaneous analysis of many known compounds is performed using the GC / MS / MS of this example, MRM measurement in which one or a plurality of transitions are determined for each target compound is performed. That is, since the retention time of the target compound (the time that the target compound flows out from the outlet of the column 12) and the mass-to-charge ratio of the ions characterizing the target compound are known, the analyst can input each target compound from the input unit 6. A measurement time range having a predetermined time width is set in the vicinity of the holding time, and a transition for performing MRM measurement within the time range is set for each measurement time range. Of course, various other measurement parameters including the cycle time are also set.
When the target compound is determined and the same kind of analysis is performed on a large number of samples as in the simultaneous analysis of residual agricultural chemicals, the measurement parameters including the measurement time range and transition described above are the same. Therefore, it is not necessary for the analyst to set the measurement parameter for each analysis, and the measurement parameter may be stored in the storage unit included in the central control unit 5 and used repeatedly.

Next, a characteristic dwell time automatic setting process executed in the GC / MS / MS of this embodiment will be described.
The measurement condition setting unit 41 calculates a dwell time per transition as in the conventional case based on the set measurement parameter. That is, as shown in FIG. 3 described above, the cycle time t _s is specified with six transitions are set in a certain measurement time range, by dividing the cycle time t _s by the number of transitions Calculate the dwell time per transition. Here, in order to simplify the description, the settling time is ignored. However, when the settling time is taken into consideration, the dwell time may be shortened uniformly by the estimated settling time.

The analysis control unit 4 controls each unit under the measurement parameters including the dwell time set identically within one measurement time range as described above (see FIG. 3), thereby controlling the predetermined compound containing the target compound. Perform analysis on the sample. As a result, in the GC unit 1, the predetermined sample is injected into the sample vaporization chamber 10, and the compound in the sample gas is temporally separated and flows out while the sample gas vaporized by the sample passes through the column 12. To do.
On the other hand, the mass analyzer 2, for each cycle time t _s in the measurement time range determined in advance, MRM measurement is repeated in order for a plurality of transitions that are specified respectively. For example, as shown in FIG. 3, a cycle in which MRM measurement is performed once for six transitions having different target precursor ions and product ions, respectively, is repeated within a predetermined measurement time range.

  The ion intensity signal obtained by the ion detector 26 by performing the MRM measurement as described above is converted into digital data by the A / D converter 27 and stored in the data collection unit 31 of the data processing unit 3.

Based on the data stored in the data collection unit 31, the mass chromatogram creation unit 32 creates a mass chromatogram for each transition, that is, for each ion to be measured. Now, for example, based on the data acquired in the measurement time range shown in FIG. 3, six mass chromatograms as shown in FIG. 2A are created.
The peak detection unit 33 performs peak detection for each mass chromatogram created as described above, and determines the peak top position (time), signal intensity, and peak range, that is, the peak start point and end point. Determine.

  Next, the SN ratio calculation unit 34 calculates the SN ratio from the mass chromatogram for each ion. For example, since the peak range on the mass chromatogram is determined by the peak detection processing by the peak detector 33, the noise level (N) is calculated from the baseline portion outside the peak range of the mass chromatogram, and the signal intensity at the peak top Is the signal level (S), and the SN ratio is calculated. Of course, the calculation method of the S / N ratio is not limited to this, and various generally known methods can be adopted. In the example of FIG. 2A, the S / N ratio calculated for each ion is assumed to be S / N = 10, 20, or 30 as described in the figure.

Optimal dwell time calculating unit 35, using the calculated SN ratio as described above, calculating the at optimal dwell time of distributing the cycle time t _s which is set Te than the ratio of the SN ratio in each ion To do. That is, the optimal dwell time calculation unit 35 calculates the dwell time t _d [n] of each ion [n] using the following equation (1).
t _d [n] = t _s × {(SN ratio of ion [n]) / (sum of SN ratios of all ions in the target measurement time range)} (1)
This equation (1) is a calculation formula that adjusts the time for taking in ion intensity data for each ion so that the SN ratio for each ion is equal, that is, the detection sensitivity is equal.

In the example shown in FIG. 2, since n = 1 to 6, the sum of the SN ratios of all ions in the target measurement time range is the sum of the SN ratios of ions [1] to [6]. Specifically, the sum of the SN ratios of ions [1] to [6] is 120. For example, since the S / N of ion [1] is 10, when the cycle time is t _s = 0.3 sec, the dwell time of ion [1] is t _d [1] = 0.3 × (10 /120)=0.025 sec. The dwell times of other ions [2] to [6] can be obtained in the same manner. As a result, as shown in FIG. 2B, the optimum dwell time in one measurement time range is determined for each ion. Similarly, the optimum dwell time for each ion is determined in the other measurement time ranges. The dwell time obtained in this way is set in the measurement condition setting unit 41.

Measurement of a sample containing the same compound as when the dwell time automatic setting process described above is performed is performed under the analysis control unit 4 using the dwell time determined as described above.
That is, first, a standard sample containing the same target compound as described above at a known concentration is used, and a calibration curve indicating the relationship between the concentration and the peak area value on the mass chromatogram is created for each compound. As described above, since detection sensitivities for ions derived from the respective compounds are almost uniform in advance, a highly accurate calibration curve can be created for any compound. Then, measure the unknown sample using the dwell time determined as described above, create a mass chromatogram for each target compound, determine the peak area value on the mass chromatogram, and refer to the calibration curve. To obtain the density value. Since the accuracy of the peak area value obtained at this time is high and the accuracy of the calibration curve is also high as described above, the concentration value of the target compound can be obtained with high accuracy and sensitivity.

  In the above embodiment, the optimum dwell time for each ion is calculated based on the equation (1) determined so that the S / N ratio for each ion is equal, but the detection sensitivity required for each ion is different. In other words, the optimum dwell time may be calculated based on the SN ratio weighted according to the required detection sensitivity. For example, if the ions [1] to [6] shown in FIG. 2A satisfy the weighted S / N ratio, the dwell time conditions when these ions are detected, that is, all The condition that the dwell times are equal is optimal.

  Moreover, in the said Example, although the optimal dwell time was calculated based on the SN ratio of the peak on a mass chromatogram, you may use the height and area of a peak instead of an SN ratio. That is, any value that reflects the detection sensitivity of ions can be used as an index value for calculating the optimum dwell time.

  Moreover, although the said Example is GC / MS / MS, LC / MS / MS may be sufficient, and it is clear that GC / MS and LC / MS may be sufficient. That is, in the above embodiment, the dwell time in the MRM measurement is optimized, but the dwell time in the SIM measurement without the selection of the precursor ion according to the mass-to-charge ratio or the dissociation operation with respect to the precursor ion is determined. The present invention can be applied to optimization as it is.

  Furthermore, the above-described embodiments are examples of the present invention, and other than the above-described modifications, even if appropriate modifications, corrections, and additions are made within the scope of the present invention, they are included in the scope of the claims of the present application. it is obvious.

DESCRIPTION OF SYMBOLS 1 ... Gas chromatograph (GC) part 10 ... Sample vaporization chamber 11 ... Column oven 12 ... Column 2 ... Mass analysis part 20 ... Vacuum chamber 21 ... Ion source 22 ... Previous stage quadrupole mass filter 23 ... Collision cell 24 ... Multipole type Ion guide 25 ... latter-stage quadrupole mass filter 26 ... ion detector 27 ... A / D converter 3 ... data processing unit 31 ... data collection unit 32 ... mass chromatogram creation unit 33 ... peak detection unit 34 ... SN ratio calculation unit 35 ... Optimal dwell time calculation unit 4 ... Analysis control unit 41 ... Measurement condition setting unit 5 ... Central control unit 6 ... Input unit 7 ... Display unit

Claims (4)

A chromatograph that separates a plurality of compounds in a sample in a time direction, and a mass analyzer that separates and detects ions derived from the compounds separated by the chromatograph according to a mass-to-charge ratio, and the mass The analysis unit can implement a measurement mode in which multiple reaction monitoring (MRM) measurement or selective ion monitoring (SIM) measurement is sequentially repeated for a plurality of ions derived from one or a plurality of compounds within a specified measurement time range. In chromatograph mass spectrometer,
a) A dwell time which is a data acquisition time for one ion in a cycle time which is one measurement period when MRM measurement or SIM measurement for a plurality of designated ions is sequentially repeated within a designated measurement time range. By performing a preliminary measurement on a predetermined sample under conditions set identically for all of the specified plurality of ions, the intensity signals of the plurality of ions in the specified measurement time range are obtained. A preliminary measurement control unit for controlling each part of the apparatus so as to obtain each;
b) An index for calculating an index value reflecting the detection sensitivity of each of the ions based on the intensity signals of the plurality of ions in the specified measurement time range acquired under the control of the preliminary measurement control unit A value calculator,
c) Based on the index value for each ion calculated by the index value calculation unit, the dwell time of each ion in the specified measurement time range is determined so that the detection sensitivity of each ion is in a predetermined state. A dwell time determination unit to
A chromatographic mass spectrometer comprising: The chromatograph mass spectrometer according to claim 1,
The index value calculation unit calculates the SN ratio calculated in the chromatogram created based on the ion intensity signal obtained by MRM measurement or SIM measurement, or the peak area or height on the chromatogram. A chromatograph mass spectrometer characterized by being calculated as an index value. The chromatograph mass spectrometer according to claim 1 or 2,
The dwell time determination unit divides the cycle time and allocates to each ion so that the dwell time is shorter as the index value is larger, based on the index value for each ion calculated by the index value calculation unit. Thus, a chromatograph mass spectrometer characterized by determining the dwell time of each ion. The chromatograph mass spectrometer according to any one of claims 1 to 3,
Under the condition of the dwell time determined by the dwell time determination unit, a measurement for creating a calibration curve of one or a plurality of compounds corresponding to the specified plurality of ions, and using the calibration curve A chromatographic mass spectrometer characterized in that measurement of a sample for compound quantification is performed.

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