JP2020194648A - Mass spectrometer - Google Patents

Abstract

To shorten a waiting time from start of a power supply for driving an ion trap until a measurement-executable state has been established, and improve measurement efficiency.SOLUTION: A mass spectrometer according to one aspect of the present invention performs mass separation of ions by using an ion trap 2 for capturing ions, and includes a voltage generator (main power supply 6) that switches an output voltage generated by a plurality of voltage sources 61 and 62 to generate a rectangular wave voltage, a correction information storage unit (voltage fluctuation correction data storage unit 54) for storing information indicating a time variation of a mass error caused by fluctuation of the output voltage or information for correcting the time variation of the mass error after a time point when a plurality of voltage sources are started, and a data processing unit (spectrum correction unit 53) that uses information stored in the correction information storage unit to correct the time variation of a mass error in a mass spectrometry result obtained by the measurement when the voltage generator is operated to execute the measurement.SELECTED DRAWING: Figure 1

Description

The present invention relates to a mass spectrometer, and more particularly to a mass spectrometer using an ion trap that captures ions by the action of a high-frequency electric field and separates the mass of the captured ions.

As one method of the mass spectrometer, an ion trap type mass spectrometer that separates the mass of ions by using an ion trap that can capture ions by the action of a high-frequency electric field is known. The ion trap consists of one ring electrode whose inner surface has a rotating one-leaf hyperboloid shape and a pair of end cap electrodes whose inner surfaces are arranged so as to face each other with the ring electrode sandwiched between them. A three-dimensional quadrupole type ion trap consisting of four substantially cylindrical rod electrodes arranged parallel to each other and a pair of end electrodes arranged on the outside of both ends thereof are linear type ion traps. well known. In this specification, for convenience, the ion trap will be described by taking "three-dimensional quadrupole ion trap" as an example, but it is clear that a linear ion trap may also be used.

In a general ion trap, a quadrupole high-frequency electric field is usually applied to the ring electrode by applying a sinusoidal high-frequency voltage to the space surrounded by the ring electrode and the end cap electrode, and the ion is vibrated by this high-frequency electric field. Confine while letting. On the other hand, an ion trap has been developed in which ions are confined by applying a square wave voltage to a ring electrode instead of a sinusoidal high frequency voltage (see Patent Document 1, Non-Patent Document 1 and the like). Such an ion trap is usually called a digital ion trap (DIT = Digital Ion Trap) because a square wave voltage having a voltage level corresponding to two logical values of "H" and "L" is used. There is.

As described in Non-Patent Document 1, in the digital ion trap, a rectangular wave voltage having a predetermined frequency corresponding to the mass-to-charge ratio (m / z) range of the ion to be captured is used as a ring as a high-frequency voltage for capture. It is applied to the electrode to confine ions in the target mass-to-charge ratio range. The captured ions are sequentially discharged from the ion outlet according to the mass-to-charge ratio, and detected by an ion detector provided outside the ion outlet.

When the ions are discharged from the inside of the ion trap to the outside in this way, the resonance excitation phenomenon of the ions is used. That is, the square wave high voltage (usually, the amplitude is several hundred V or more) applied to the ring electrode is divided by a predetermined frequency division ratio (for example, 1/4 frequency division), and the square wave low voltage (usually, the amplitude is about several V). And "low voltage" because it is much smaller than the above-mentioned square wave high voltage) is applied to the end cap electrode, and the frequencies are scanned synchronously while maintaining the amplitude of the square wave voltage constant. As a result, among the ions trapped in the ion trap, the ions having a specific mass-to-charge ratio corresponding to the frequency of the square wave voltage are sequentially resonantly excited and vibrated greatly, and are discharged to the outside through the ion outlet. By detecting the exhaled ions with an ion detector and obtaining an intensity signal according to the amount of ions, a mass spectrum over a predetermined mass-to-charge ratio range can be created.

Japanese Unexamined Patent Publication No. 2011-96542

Furuhashi and 6 others, "Development of Digital Ion Trap Mass Spectrometer", Shimadzu Criticism, Shimadzu Criticism Editorial Department, March 31, 2006, Vol. 62, Nos. 3.4, pp.141-151

Usually, the rectangular wave high voltage is generated by switching the output voltage of the DC high voltage power supply. Therefore, the amplitude (peak value) of the rectangular wave high voltage depends on the stability of the output voltage of the DC high voltage power supply. The mass accuracy of a mass spectrometer using a digital ion trap is greatly affected by the amplitude of the rectangular wave high voltage, and when the amplitude fluctuates, the mass accuracy decreases accordingly. In general, in a DC high-voltage power supply, it takes a considerable amount of time from the start to the stabilization of the output voltage, so that a satisfactory mass accuracy cannot be obtained in the period from the start to the stabilization of the voltage output.

FIG. 4 is an example of the result of actually measuring the change in the mass error with the passage of time from the start of the conventional mass spectrometer. The compound to be measured is human adrenocorticotropic hormone: ACTH18-39 (m / z 2465.2), and the mass is based on the result of measuring ACTH18-39 every 5 minutes from the time when the DC high-voltage power supply for driving the ion trap is started. The error is calculated. As can be seen from the figure, the mass error exceeds ± 50 ppm from the start to about 20 minutes, and after about 20 minutes, the mass error converges within ± 50 ppm and is stable. Therefore, conventionally, it is set as a period during which measurement is not possible (or measurement is possible but accuracy is not guaranteed) from the time of startup until a predetermined time elapses.

In recent years, there has been a demand for miniaturization, weight reduction, and cost reduction of mass spectrometers, and for that purpose, it is necessary to use a compact, lightweight, and inexpensive DC high-voltage power supply. However, in general, with a small, lightweight, or inexpensive DC high-voltage power supply, the time required for the output voltage to stabilize tends to be long, which causes a problem that the waiting time, which cannot be measured by a mass spectrometer, becomes long. There is.

The present invention has been made to solve the above problems, and is used for driving an ion trap in a mass spectrometer that uses a digital ion trap to selectively discharge and detect ions from the ion trap by resonance excitation discharge. Its main purpose is to improve the efficiency of measurement by shortening the waiting time from when the power is turned on until measurement becomes possible.

The mass spectrometer according to the first aspect of the present invention, which has been made to solve the above problems, has an ion trap that captures ions, and uses the ion trap to perform mass separation of ions. And
A voltage generator that switches the output voltage generated by each of the plurality of voltage sources to generate a rectangular wave voltage for driving the ion trap, and
A correction information storage unit that stores information indicating a time change of mass error due to fluctuations in output voltage or information for correcting the time change of the mass error since the time when the plurality of voltage sources are started.
A data processing unit that uses the information stored in the correction information storage unit to correct the time change of the mass error in the mass spectrometry result obtained by the measurement when the voltage generation unit is operated to execute the measurement. ,
Is provided.

In the mass spectrometer according to the first aspect, when the ion trap is a three-dimensional quadrupole ion trap, the frequency of the rectangular wave voltage applied to the ring electrode is changed to change the mass-to-charge ratio of the resonance-excited ions. By doing so, the mass-to-charge ratio of the ion to be detected is scanned. Even if the frequency of the square wave voltage is the same, if the amplitude of the square wave voltage (strictly speaking, the voltage on the high level side and the voltage on the low level side) fluctuates, the mass-to-charge ratio of the ions that are resonantly excited changes. It becomes a mass error. With the same type of voltage source having the same circuit configuration, the similarity of the time variation of the output voltage from the time when the voltage output is started to the time when the output voltage stabilizes is high. In addition, the reproducibility of the time variation of the output voltage is high.

Therefore, for example, the manufacturer of this device indicates the time change of the mass error due to the fluctuation of the output voltage after the time when the voltage source is started, based on the experimentally measured result at the time of manufacturing or adjusting the device. Alternatively, information for correcting the time change of the mass error is created and stored in the correction information storage unit. When the user executes the measurement, the data processing unit corrects the time change of the mass error in the mass spectrometry result obtained by the measurement by using the information stored in the correction information storage unit.

According to the mass spectrometer according to the first aspect, the mass error caused by the fluctuation of the output voltage after the time when the power supply unit for driving the ion trap is started is generally corrected. As a result, the measurement can be performed before the output voltage of the power supply unit becomes stable, that is, immediately after the start-up, and the measurement efficiency can be improved. Further, since the time for aging the power supply unit can be substantially eliminated, it is not necessary to wastefully keep the power supply unit in the energized state, and the power consumption can be saved.

The schematic block diagram of DIT-MS which is one Embodiment of this invention. The schematic block diagram of DIT-MS which is another embodiment of this invention. The waveform diagram which shows an example of the rectangular wave voltage waveform at the time of resonance excitation discharge in DIT-MS of this embodiment. The figure which shows an example of the result of having measured the change of the mass error with the lapse of time from the start-up in the conventional mass spectrometer. The figure which shows an example of the time change of the output voltage of a DC power supply part.

A digital ion trap mass spectrometer (DIT-MS), which is an embodiment of the mass spectrometer according to the present invention, will be described with reference to the accompanying drawings.

FIG. 1 is a block diagram of a main part of the DIT-MS of the present embodiment. Further, FIG. 3 is a waveform diagram showing an example of a rectangular wave voltage waveform at the time of resonance excitation discharge in the DIT-MS of the present embodiment.
This DIT-MS has an ionization unit 1 that ionizes a target sample, a three-dimensional quadrupole type ion trap 2 that separates ions according to a mass-to-charge ratio, a detection unit 3 that detects ions, and a detection signal. It includes a digital-to-analog conversion unit (DAC) 4 for digitization, a data processing unit 5, a main power supply unit 6, an auxiliary power supply unit 7, a timing signal generation unit 8, and a control unit 9.

The ionization unit 1 uses a matrix-assisted laser desorption / ionization (MALDI) method, and includes a laser irradiation unit 11 that emits a pulsed laser beam, a sample plate 12 to which a sample 13 containing a sample component is attached, and a laser beam. The aperture electrode 14 that draws out the ions emitted from the sample 13 by the irradiation of the sample 13 and limits the drawing direction thereof, the ion lens 15 that guides the extracted ions, and the like are included. Of course, the type of ionization method in the ionization unit 1 is not limited to the MALDI method, and other laser ionization methods such as the LDI method and the SALDI method or an ionization method that does not use laser light may be used.

The ion trap 2 is composed of one annular ring electrode 21, an inlet side end cap electrode 22 and an outlet side end cap electrode 24 arranged so as to sandwich the ring electrode 21, and three of these. A part of the space surrounded by the electrodes 21, 22 and 24 becomes an ion trapping region. An ion incident port 23 is bored substantially in the center of the inlet side end cap electrode 22, and the ions emitted from the ionization unit 1 are introduced into the ion trap 2 through the ion incident port 23. On the other hand, an ion emission port 25 is formed substantially in the center of the outlet side end cap electrode 24, and the ions discharged through the ion emission port 25 reach the detection unit 3 and are detected.

The detection unit 3 generates a detection signal according to the amount of incident ions, and the DAC 4 converts this detection signal into digital data and sends it to the data processing unit 5. The data processing unit 5 includes functional blocks such as a data storage unit 51, a spectrum creation unit 52, a spectrum correction unit 53, and a voltage fluctuation correction data storage unit 54, and creates, for example, a mass spectrum based on the data collected by measurement. , Displayed on the screen of the display unit 55.

The main power supply unit 6 applies a rectangular wave high voltage to the ring electrode 21 of the ion trap 2, and has a first voltage source 61 that generates a first voltage V _H that is positive and a second voltage V _L that is negative. The first switching element 63 and the second switching element 64 connected in series between the output end of the first voltage source 61 and the output end of the second voltage source 62. Including. The auxiliary power supply unit 7 applies different rectangular wave low voltages to the end cap electrodes 22 and 24 of the ion trap 2.

The timing signal generation unit 8 is a logic circuit by hardware, and the first switching element 63 and the second switching element 64 may be turned on alternately (however, at least at the same time) under the control of the control unit 9. (Not so), a drive pulse of a predetermined frequency is generated and supplied to the switching elements 63 and 64. The first voltage V _H is output when the first switching element 63 is turned on, and the second voltage V _L is output when the second switching element 64 is turned on. Therefore, ideally, as shown in FIG. 3A, the output voltage V _OUT of the main power supply unit 6 is a rectangular wave having a predetermined frequency f (period t) in which the high level is V _H and the low level is _VL. It becomes a voltage. V _H and V _L are high voltages having substantially the same absolute value and opposite polarities. For example, the absolute value is about several hundred V to 1 kV. The frequency f of the rectangular wave voltage is usually in the range of several tens of kHz to several MHz. However, depending on the reference potential of the system, V _H and V _L may have the same polarity.

The timing signal generation unit 8 gives the auxiliary power supply unit 7 a pulse signal obtained by dividing the drive pulse supplied to the main power supply unit 6 by an appropriate ratio (for example, 1/4). The auxiliary power supply unit 7 generates a rectangular wave low voltage as shown in FIG. 3B, which has a frequency of f / 4 and an amplitude value of, for example, about several V, based on the signal obtained from the timing signal generation unit 8. To do. The control unit 9 controls each unit in order to carry out the measurement.

The data processing unit 5 and the control unit 9 can be configured by a hardware circuit, but usually at least a part thereof is configured around a personal computer, and a dedicated control installed in the personal computer is used. By executing the processing program, the function can be achieved. That is, the data processing unit 5 may be a device integrated with the device main body that executes the measurement, but may be a device different from the device main body.

A typical measurement operation in the DIT-MS of the present embodiment will be schematically described.
When the laser beam is emitted from the laser irradiation unit 11 to the sample 13 for a short time under the control of the control unit 9, the ionization unit 1 ionizes the sample components in the sample 13. The generated ions are converged by the ion lens 15, introduced into the space inside the ion trap 2 through the ion incident port 23, and captured.

The mass-to-charge ratio range of ions stably captured in the ion trap 2 depends on the frequency of the rectangular wave high voltage applied to the ring electrode 21. Therefore, when the ions are confined in the ion trap 2, the timing signal generation unit 8 supplies a drive pulse of a predetermined frequency to the switching elements 63 and 64 according to the instruction from the control unit 9, and the rectangular wave height of the corresponding frequency is supplied. A voltage is generated in the main power supply unit 6 and applied to the ring electrode 21. At this time, the potentials of the end cap electrodes 22 and 24 are maintained at the ground potential. When capturing ions in a predetermined mass-to-charge ratio range, the frequency of the rectangular wave high voltage is appropriately selected according to the mass-to-charge ratio range.

When acquiring the mass spectrum of the ion after capturing the ions having various mass-to-charge ratios, the resonance excitation phenomenon is used to discharge the ions from the ion trap 2 through the ion outlet 25 in the order of the mass-to-charge ratio. , Detected by the detection unit 3. At this time, the main power supply unit 6 applies a rectangular wave high voltage for ion capture to the ring electrode 21, while the auxiliary power supply unit 7 applies the rectangular wave high voltage for ion capture to the end cap electrodes 22 and 24, respectively. A square wave voltage for resonance excitation (square wave low voltage) is applied. Then, the frequencies of the rectangular wave high voltage and the rectangular wave low voltage for ion capture are scanned synchronously. As a result, ions having a specific mass-to-charge ratio are sequentially resonantly excited and vibrated greatly, and are discharged to the outside through the ion outlet 25.

The detection unit 3 outputs a detection signal according to the amount of ions incident during mass scanning, and data based on this signal is stored in the data storage unit 51 of the data processing unit 5. The spectrum creation unit 52 reads out the data obtained during one mass scan from the data storage unit 51, creates a mass spectrum in which the horizontal axis is the mass-to-charge ratio and the vertical axis is the signal strength, and the display unit 55 displays the mass spectrum. Output and display.

Generally, the above measurement is performed after starting the first voltage source 61 and the second voltage source 62 and waiting until their output voltages become stable. FIG. 5 is an example of the results of measuring the time change of the output voltage of the voltage sources used as the first voltage source 61 and the second voltage source 62 in this type of mass spectrometer. In this example, the output voltage fluctuates considerably from the start to about 20 minutes. Further, the changes in the output voltages of the two voltage sources, positive electrode and negative electrode, are not the same, and even if the degree of these changes is the same, the mass deviation with respect to the voltage change is on the positive electrode side and the negative electrode side. Since it is not the same as, it is inevitable that a mass error will occur until the output voltage stabilizes. This is as already described with reference to FIG.

Therefore, in the DIT-MS of the present embodiment, the mass error of the measurement until the output voltage immediately after the start of the voltage sources 61 and 62 stabilizes is corrected as follows, and the useful measurement is performed immediately after the start. I am trying to do it.

The characteristics of the temporal change of the output voltage of the voltage source that outputs a high voltage are reproducible because they depend on the circuit configuration and the characteristics of the circuit components used. That is, in one mass spectrometer, the pattern showing the time change of mass accuracy as shown in FIG. 4 can be regarded as the same unless major repairs such as replacement of the voltage source are performed. Therefore, the manufacturer of the mass spectrometer of the present embodiment carries out a preliminary experiment at the stage of assembling and adjusting the device, acquires correction data based on the experimental result, and stores the data in the voltage fluctuation correction data storage unit 54. Remember it.

Specifically, in the preliminary experiment, the precise mass is known for a predetermined period from the time when both the first voltage source 61 and the second voltage source 62 of the main power supply unit 6 are started until the output voltage becomes stable. A sample containing a component (for example, ACTH18-39) is repeatedly measured at regular time intervals, and a mass spectrum in which a peak derived from the component can be observed is obtained. Then, from a large number of the obtained mass spectra, the time change data of the mass error amount as shown in FIG. 4 is obtained. Then, based on the measured data of the mass error amount, the relationship between the passage of time and the mass error amount in the period from the time when the first voltage source 61 and the second voltage source 62 are started until the output voltage stabilizes is shown. Calculate the approximate expression. When calculating the approximate expression, a general fitting method such as the least squares method may be used. The approximate expression itself obtained in this way may be stored as correction data, or a table for deriving the correction amount of the mass-to-charge ratio value for each elapsed time from the approximate expression may be obtained and this table may be stored as correction data. ..

In addition, voltage sources of the same type usually show almost the same output voltage over time even if the individual is different. Therefore, the time variation of mass accuracy often shows a similar pattern between different mass spectrometers using the same type of voltage source for the first and second voltage sources 61 and 62. Therefore, it is not always necessary to carry out the preliminary experiment as described above for each mass spectrometer to obtain the correction data. That is, one standard device is determined for a plurality of mass spectrometers using the same type of voltage source, and the correction data obtained from the result of the preliminary experiment using the standard device is used as the voltage of the same type. It may be applied to other mass spectrometers that use the source.

When the mass spectrometer in which the appropriate correction data is stored in the voltage fluctuation correction data storage unit 54 as described above is used and the measurement is performed on an arbitrary sample, the following processing is performed. ..

That is, when the control unit 9 activates the first and second voltage sources 61 and 62 to perform the measurement, the control unit 9 notifies the data processing unit 5 to that effect. After that, under the control of the control unit 9, the ionization unit 1, the ion trap 2, the detection unit 3, and the like are driven to perform measurement, and the mass spectrum data is stored in the data storage unit 51. At this time, data indicating the elapsed time when the measurement is performed is added to the mass spectrum data starting from the time when the first and second voltage sources 61 and 62 are started.

The spectrum creation unit 52 creates a mass spectrum based on the stored mass spectrum data. The spectrum correction unit 53 calculates the amount of mass error corresponding to the elapsed time based on the elapsed time data added to the mass spectrum data and the correction data stored in the voltage fluctuation correction data storage unit 54. Correct the mass-to-charge ratio axis of the mass spectrum to correct the mass error. Then, the mass spectrum corrected by the mass error is displayed on the screen of the display unit 55.

As described above, in the DIT-MS of the present embodiment, the mass spectrum having higher mass accuracy than the conventional one is acquired even before the output voltages of the first and second voltage sources 61 and 62 are stabilized. be able to. Therefore, the measurement result can be confirmed without waiting for the output voltage to stabilize.

In the DIT-MS of the above embodiment, the mass spectrum data (profile data) including the mass error due to the fluctuation of the output voltage is transferred from the measurement unit side to the data processing unit 5 and stored in the data storage unit 51. The mass error is corrected when creating the mass spectrum. On the other hand, the mass error may be corrected on the measurement unit side, and the corrected mass spectrum data may be transferred to the data processing unit 5 and stored in the data storage unit 51. In either case, the mass accuracy of the resulting mass spectrum is the same.

However, in the former case, raw data including mass error remains, whereas in the latter case, such raw data does not remain. Therefore, for example, the former is more appropriate when there is doubt about the mass spectrum finally obtained and it is confirmed whether the measurement is inappropriate or the data processing (correction) is inappropriate. ..

In the DIT-MS of the above embodiment, the correction data is stored in the voltage fluctuation correction data storage unit 54 at the time when the user obtains the device, but it has a function that the user can create the correction data. You may let me.

FIG. 2 is a block diagram of a main part of DIT-MS according to another embodiment of the present invention. The difference from the apparatus shown in FIG. 1 is that the voltage fluctuation correction data creation unit 56 is added to the data processing unit 5, and the control unit 9 has the voltage fluctuation correction data acquisition control unit 91 as a functional block. ..

That is, in the DIT-MS of this embodiment, when the user performs a predetermined operation with an operation unit (not shown), the voltage fluctuation correction data acquisition control unit 91 causes the first voltage source 61 and the second voltage source as described above. The ionization unit 1, the ion trap 2, and the like are controlled so as to repeatedly perform the measurement for acquiring the correction data for correcting the mass error caused by the fluctuation of the output voltage of 62. On the other hand, the voltage fluctuation correction data creation unit 56 creates correction data for correcting the mass error based on the data obtained by the measurement repeatedly performed under the control of the voltage fluctuation correction data acquisition control unit 91. , This is stored in the voltage fluctuation correction data storage unit 54.
As a result, the correction data can be acquired under the environment in which the DIT-MS is actually used, so that the accuracy of the correction of the mass error can be improved.

In the above embodiment, a three-dimensional quadrupole ion trap is used as the ion trap, but it is natural that the ion trap can be replaced with a linear ion trap.

Furthermore, the above-described embodiment is merely an example of the present invention, and it is natural that the present invention is included in the claims even if it is appropriately modified, added, or modified within the scope of the present invention.

[Various aspects]
It will be understood by those skilled in the art that the above-described exemplary embodiments are specific examples of the following embodiments.

The mass spectrometer according to the first aspect is a mass spectrometer having an ion trap for capturing ions and performing mass separation of ions using the ion trap.
A voltage generator that switches the output voltage generated by each of the plurality of voltage sources to generate a rectangular wave voltage for driving the ion trap, and
A correction information storage unit that stores information indicating a time change of mass error due to fluctuations in output voltage or information for correcting the time change of the mass error since the time when the plurality of voltage sources are started.
A data processing unit that uses the information stored in the correction information storage unit to correct the time change of the mass error in the mass spectrometry result obtained by the measurement when the voltage generation unit is operated to execute the measurement. ,
To be equipped.

In the mass spectrometer according to the first aspect, even if the output voltage is not sufficiently stable and fluctuates immediately after the voltage source is started, the measurement mass error due to the voltage fluctuation is obtained. Is corrected by data processing. Therefore, according to the mass spectrometer according to the first aspect, the measurement can be performed before the output voltage of the power supply unit stabilizes, that is, immediately after the start-up, and it is necessary to wait until the output voltage stabilizes as in the conventional case. Therefore, the measurement efficiency is improved.

The mass spectrometer according to the second aspect is the mass spectrometer according to the first aspect, the mass analysis result is a mass spectrum, and the data processing unit has a mass charge each time a mass spectrum is obtained by measurement. Corrections that shift the ratio axis can be performed.

According to the mass spectrometer according to the second aspect, it is possible to acquire a mass spectrum with high mass accuracy before the output voltage of the power supply unit stabilizes.

The mass spectrometer according to the third aspect is the mass spectrometer according to the first or second aspect, and the fluctuation of the output voltage is based on the result of the measurement performed after the time when the plurality of voltage sources are started. A correction information creation unit for acquiring information indicating a time change of the mass error due to the above can be further provided.

According to the mass spectrometer according to the third aspect, since information on the mass error in the environment in which the device is installed can be collected, the accuracy of correction of the mass error can be improved.

1 ... Ionization unit 11 ... Laser irradiation unit 12 ... Sample plate 13 ... Sample 14 ... Aperture electrode 15 ... Ion lens 2 ... Ion trap 21 ... Ring electrodes 22, 24 ... End cap electrodes 23 ... Ion inlet 25 ... Ion outlet 3 ... Detector 4 ... Digital-to-analog converter (DAC)
5 ... Data processing unit 51 ... Data storage unit 52 ... Spectrum creation unit 53 ... Spectrum correction unit 54 ... Voltage fluctuation correction data storage unit 55 ... Display unit 56 ... Voltage fluctuation correction data creation unit 6 ... Main power supply units 61, 62 ... Voltage Sources 63, 64 ... Switching element 7 ... Auxiliary power supply unit 8 ... Timing signal generation unit 9 ... Control unit 91 ... Voltage fluctuation correction data acquisition control unit

Claims (3)

A mass spectrometer having an ion trap that captures ions and performing mass separation of ions using the ion trap.
A voltage generator that switches the output voltage generated by each of the plurality of voltage sources to generate a rectangular wave voltage for driving the ion trap, and
A correction information storage unit that stores information indicating a time change of mass error due to fluctuations in output voltage or information for correcting the time change of the mass error since the time when the plurality of voltage sources are started.
A data processing unit that uses the information stored in the correction information storage unit to correct the time change of the mass error in the mass spectrometry result obtained by the measurement when the voltage generation unit is operated to execute the measurement. ,
A mass spectrometer equipped with. The mass spectrometer according to claim 1.
The mass spectrometry result is a mass spectrum, and the data processing unit performs a correction for shifting the mass-to-charge ratio axis each time a mass spectrum is obtained by measurement. The mass spectrometer according to claim 1 or 2.
A mass spectrometer further comprising a correction information creation unit that acquires information indicating a time change of a mass error due to a fluctuation in an output voltage based on the results of measurements performed after the time when the plurality of voltage sources are started. ..

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