JP5454716B2 - Mass spectrometry data processing method and mass spectrometer - Google Patents

Description

  The present invention relates to a processing method for processing data obtained by a mass spectrometer and a mass spectrometer for performing such a data processing method, and more particularly, data for removing noise superimposed on data collected by mass spectrometry. It relates to processing technology.

  In a chromatograph mass spectrometer that combines a high-performance liquid chromatograph (LC) or gas chromatograph (GC) and a mass spectrometer (MS), LC or GC can be obtained by repeating mass analysis over a preset measurement mass range. Mass spectra for various components eluted from the column can be obtained from time to time. As an ion detector of a mass spectrometer, a combination of a conversion dynode or a microchannel plate and a secondary electron multiplier is generally used.

  Such an electric circuit such as an ion detector, a subsequent current / voltage converter, or an amplifier generates electric noise and may be subject to external noise. Therefore, the detection signal acquired at the time of mass scanning is obtained by superimposing the electrical noise signal on the signal derived from ions derived from the sample. Therefore, in the conventional mass spectrometer, the noise component due to the electrical factors as described above is measured before the measurement of the target sample, and the noise information obtained by the measurement is obtained from the mass spectrum information of the target sample. A process of removing noise is performed by subtraction.

  Further, in the mass spectrometer, an averaging process using data obtained by a plurality of mass scans is performed in order to stabilize the shape of the spectrum. Further, for example, as in the apparatus described in Patent Document 1, switching between a positive ion measurement mode and a negative ion measurement mode for each mass scan, or a normal mass analysis and an MS / MS analysis with a cleavage operation for each mass scan, However, there are cases where the number of mass scans of the data for the averaging process differs depending on the different analysis conditions. Since the noise state is different when the number of mass scans is different, the noise information obtained by measuring the noise component is subjected to statistical processing in consideration of the number of mass scans, and the noise information is appropriately processed to remove noise. I have to.

  However, since the state of electrical noise in circuits such as ion detectors and amplifiers is affected by temperature and the like, the noise level usually varies with time. For this reason, even if noise removal processing is performed using noise information preliminarily measured before execution of measurement of the target sample, noise may not necessarily be removed appropriately.

  In order to avoid the above problems, the noise component is remeasured not only before the measurement of the target sample but also during the measurement, and the noise using the noise information obtained by the measurement is measured. A removal process may be performed. However, since the measurement for the target sample and the measurement of the noise component are performed at a certain distance, even if electrical noise increases during the measurement of the target sample, this is sufficiently reflected in the noise information. However, the noise removal effect may not be exhibited.

JP 2001-99821 A

  The present invention has been made in view of the above problems, and an object of the present invention is to accurately remove mass noise caused by an ion detector, an amplifier, etc., and to create a highly accurate mass spectrum. An object of the present invention is to provide a mass spectrometry data processing method and a mass spectrometer.

A first invention made to solve the above problems includes an ion source, a mass separator that mass-separates ions generated by the ion source, and a detector that detects mass-separated ions. A data processing method for processing data collected by a mass spectrometer to create a mass spectrum over a predetermined mass range,
a) Noise information that extracts data in a range where ions derived from the sample do not reach the detector from measurement data collected for mass scanning, and performs statistical processing based on the data to calculate a threshold value An acquisition step;
b) Profile data acquisition step for extracting data corresponding to the measurement mass range in the measurement data as profile data;
c) a noise removal processing step of removing a noise component from the profile data using the threshold;
d) a spectrum creation step for creating a mass spectrum using the profile data from which noise has been removed;
It is characterized by having.

The second invention made to solve the above problems is an apparatus for carrying out the mass spectrometry data processing method according to the first invention, and mass-separates the ion source and the ions generated by the ion source. A mass separator, a detector for detecting mass-separated ions, and a data processing unit for processing measurement data for creating a mass spectrum over a predetermined mass range obtained by the detector. In the mass spectrometer, the data processing unit
a) noise information acquisition means for extracting data in a range where ions derived from a sample do not reach the detector from measurement data collected for mass scanning, and calculating a threshold based on the data;
b) Profile data acquisition means for extracting data corresponding to the measurement mass range in the measurement data as profile data;
c) noise removal processing means for removing a noise component from the profile data using the threshold;
d) spectrum creation means for creating a mass spectrum using the profile data from which noise has been removed;
It is characterized by having.

  Here, the aspect and structure of the mass separator are not particularly limited, but examples include a time-of-flight mass separator and a quadrupole mass filter. In the case of a time-of-flight mass separator, a mass scan is from the point in time when ions are introduced into the time-of-flight mass separator, or from an ion trap or the like to introduce ions into the time-of-flight mass separator. It means that a detection signal is continuously obtained by an ion detector from the time of emission until a predetermined time elapses. On the other hand, in the case of a quadrupole mass filter, mass scanning means that the voltage applied to the electrode of the filter is swept within a predetermined range and a detection signal is continuously obtained by an ion detector during that time.

  The data processing unit in the mass spectrometer according to the second invention that implements the mass spectrometry data processing method according to the first invention is a measurement data range from a series of measurement data obtained for one mass scan. In view of this, data obtained during a period in which ions derived from the sample supplied to the ion source do not reach the detector are distinguished from data obtained during a period corresponding to the measurement mass range. Both of these data include electrical noise such as detectors, but the signal intensity of ions derived from the sample is included only in the latter. Therefore, the noise information acquisition means calculates a threshold value as noise information from the former data, and the noise removal processing means executes processing for removing noise from the latter data extracted by the profile data acquisition means using the threshold value. To do. Thereby, since the noise component contained in the profile data is removed, the spectrum creation means creates a mass spectrum based on the data after the removal process.

  That is, in the data processing method according to the first invention and the mass spectrometer according to the second invention, both the spectrum information reflecting the ion intensity for each mass and the noise component information are obtained in one mass scan. can get. Strictly speaking, they were not obtained at the same time, but since the time required for one mass scan is usually short, it can be considered that they were obtained at the same time. Since the temporal fluctuation factor of noise is negligibly small, the electrical noise component superimposed on the profile data can be accurately removed. In addition, except for pulse-like noise that occurs only for a very short time, a certain amount of burst-like noise can be removed accurately. Thereby, the accuracy of the mass spectrum can be improved.

  When the mass separator is a time-of-flight mass separator as described above, a period from when the ion is introduced into the time-of-flight mass separator until the ion having the smallest mass in the measurable mass range reaches the detector, and There should be no ions incident on the detector during the period from when the maximum mass ion in the measurable mass range reaches the detector until the end of data collection for that single mass scan. Therefore, for example, the noise information acquisition unit can extract the data corresponding to one or both of the two periods and obtain the threshold value.

  However, there are cases where the signal intensity of ions is observed during a period when ions derived from the sample should not reach the detector due to unintended ion flight delays and the like. Therefore, in order to eliminate this, it is preferable not to reflect this in the noise information, that is, the threshold value when the signal intensity is a predetermined value or more.

An aspect of the mass spectrometer according to the second invention is a mass spectrometer capable of repeatedly performing mass scanning under a plurality of different analysis conditions,
A condition setting unit that inputs and sets the analysis conditions at the time of mass scanning, and mass scanning of a plurality of conditions with different analysis conditions that are input and set by the condition setting unit is set as one cycle, and each cycle is repeated while repeating this cycle. An analysis control means for collecting corresponding data;
The noise information acquisition means may be configured to extract data corresponding to noise from measurement data obtained for each mass scan under each analysis condition.

Here, the analysis conditions are conditions that affect the ion generation state and detection state. For example, the polarity of ions generated by the ion source (ionization polarity), the measurement mass range, and a spectrum for forming spectral information. The number of times of averaging (number of times of mass scanning) can be combined. In addition, when MS ⁿ analysis with a cleavage operation is possible, the value of n can be added to one of the combinations of analysis conditions.

  In the mass spectrometer of the above aspect, even when mass scanning is repeated under different analysis conditions, noise information is obtained together with spectrum information for each mass scanning. Therefore, even when the analysis conditions, particularly the spectrum averaging times, are different, accurate noise information can be grasped and noise removal can be performed with high accuracy without performing statistical processing in consideration of the averaging times.

The block diagram of the principal part of LC / IT-TOFMS which is one Example of this invention. The function block diagram of the principal part in a data processing part. The flowchart which shows the control / processing procedure of the characteristic operation | movement in the apparatus of a present Example. Operation | movement explanatory drawing centering on the signal waveform obtained by one mass scanning. The figure which shows an example of the setting content of event measurement conditions. Explanatory drawing of operation | movement in repeated mass scanning.

  A liquid chromatograph / ion trap time-of-flight mass spectrometer (LC / IT-TOFMS) which is an embodiment of the present invention will be described in detail with reference to FIGS.

  FIG. 1 is a configuration diagram of a main part of the LC / IT-TOFMS of this embodiment. The LC / IT-TOFMS is roughly divided into a liquid chromatograph (LC) unit 1 and a mass spectrometry (MS) unit 2, and an atmospheric pressure ionization interface for connecting the LC unit 1 and the MS unit 2 is used. Electrospray ionization (ESI) interfaces are used. The ionization method is not limited to this, and various other forms of ionization interfaces such as atmospheric pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI) can be used.

  In the liquid chromatograph (LC) unit 1, the liquid feed pump 12 sucks the mobile phase stored in the mobile phase container 11 and feeds it to the column 14 through the injector 13 at a constant flow rate. When the sample is injected by the injector 13, the sample is introduced into the column 14 along the flow of the mobile phase. Various components in the sample are separated while passing through the column 14, and are eluted from the outlet of the column 14 with a time lag and introduced into the mass spectrometry (MS) unit 2.

  The MS unit 2 includes an ionization chamber 21 that is maintained in an atmospheric pressure atmosphere, and an analysis chamber 29 that is evacuated by a turbo molecular pump (not shown) and maintained in a high vacuum atmosphere. First and second intermediate vacuum chambers 24 and 27 having a gradually increased degree of vacuum are arranged. The ionization chamber 21 and the first stage intermediate vacuum chamber 24 communicate with each other through a small-diameter desolvating tube 23, and the first stage intermediate vacuum chamber 24 and the second stage intermediate vacuum chamber 27 are conical skimmers. It communicates through a small-diameter orifice drilled in the top of the 26.

  When the eluate containing the sample components supplied from the LC unit 1 reaches the ESI nozzle 22 as an ion source, the eluate imparts a biased charge due to a DC high voltage applied from a high voltage power source (not shown). Is done. Then, it is sprayed into the ionization chamber 21 as charged fine droplets. These charged droplets collide with gas molecules derived from the atmosphere and are pulverized into finer droplets, which are quickly dried (desolvated) to vaporize sample molecules. The sample molecules are ionized by causing an ion evaporation reaction. The microdroplets containing the generated ions are drawn into the desolvation tube 23 by the differential pressure, and further desolvation proceeds while passing through the desolvation tube 23 to generate ions. The ions pass through the two intermediate vacuum chambers 24 and 27 while being converged by the ion guides 25 and 28 and are sent to the analysis chamber 29. In the analysis chamber 29, ions are introduced into a three-dimensional quadrupole ion trap 30.

  In the ion trap 30, ions are once trapped and accumulated by a quadrupole electric field formed by a high-frequency voltage applied to each electrode from a power source (not shown). Various ions accumulated in the ion trap 30 are given kinetic energy all at a predetermined timing and are emitted from the ion trap 30 toward a time-of-flight mass separator (TOF) 31 as a mass separator. . That is, the ion trap 30 is the starting point for the flight of ions to the TOF 31. The TOF 31 includes a reflectron electrode 32 to which a DC voltage is applied from a direct power source (not shown), and ions are folded by the action of a DC electric field formed thereby to reach an ion detector 33 as a detector. . The ions emitted from the ion trap 30 simultaneously fly faster as the mass / charge ratio m / z is smaller, and reach the ion detector 33 with a time difference corresponding to m / z. The ion detector 33 outputs a current corresponding to the number of reached ions as a detection signal.

  This detection signal is converted into a voltage signal by the I / V converter 34 and amplified by the amplifier 35. Then, after being converted into a digital value by the A / D converter 36, it is input to the data processing unit 40. The data processing unit 40 measures the signal intensity of ions for each time from when the ions are simultaneously emitted from the ion trap 30 until reaching the ion detector 33, converts the time information into mass information, Create a mass spectrum with the horizontal axis representing the m / z value and the vertical axis representing the signal intensity. Further, a total ion chromatogram and a mass chromatogram are created as time elapses.

  The analysis control unit 42 controls the operation of each unit of the LC unit 1 and the MS unit 2 to execute LC / MS analysis based on an instruction from the central control unit 43. An operation unit 44 and a display unit 45 serving as user interfaces are connected to the central control unit 43, and various commands for analysis in response to an operator's operation by the operation unit 44 are analyzed and the data processing unit 40. And the analysis result such as the mass spectrum is output to the display unit 45. It should be noted that most of the central control unit 43, the analysis control unit 42, and the data processing unit 40 can be realized by a personal computer equipped with predetermined control / processing software.

As shown in the figure, a collision induced dissociation (CID) gas such as argon can be supplied to the ion trap 30, and ions accumulated in the ion trap 30 are cleaved by the CID to generate product ions. it can. When performing MS ⁿ analysis such as MS / MS analysis, first, various ions are accumulated in the ion trap 30, and then only ions having a specific mass among the ions are selectively left as precursor ions. The CID gas is then introduced into the ion trap 30 to promote the cleavage of the precursor ions. The product ions thus generated are released from the ion trap 30 toward the TOF 31 all at once, and separated and detected for each m / z, whereby the mass spectrum of the product ions can be obtained.

  FIG. 2 is a functional configuration diagram of a main part of the data processing unit 40 for performing a characteristic operation.

  Detection data obtained by digitizing the detection signal obtained by the ion detector 33 as described above is sequentially stored in the detection data storage unit 400 by the detection data reading unit 401. The profile data read addition processing unit 402 selectively reads out data (profile data) corresponding to the measured mass range from among the data stored in the detection data storage unit 400 and has already been stored in the profile integration data storage unit 403. The data is stored in the storage unit 403 so as to be added to existing data. On the other hand, the noise component data read addition processing unit 405 selectively reads out data (noise component data) corresponding to outside the measured mass range from among the data stored in the detection data storage unit 400, and the noise component integrated data storage unit The data is stored in the storage unit 406 so as to be added to the data already stored in 406. The above processing is executed almost in real time as detection data is obtained during mass scanning in the MS unit 2.

  The profile data averaging processing unit 404 performs integration processing for the number of times of averaging set as an event measurement condition described later, and then reads the integration data stored in the profile integration data storage unit 403 and averages it. The average value is obtained by dividing by the number of times. Similarly, after the integration process ends, the noise information calculation unit 407 reads the integration data from the noise component integration data storage unit 406 and calculates noise information such as a noise level (intensity) and standard deviation. The profile data noise removal processing unit 408 performs noise removal calculation using the noise information, and calculates profile data from which the influence of noise is eliminated.

  A characteristic operation in the LC / IT-TOFMS having the above configuration will be described with reference to FIGS. FIG. 3 is a flowchart showing the control / processing procedure of this operation. FIG. 4 is an operation explanatory diagram centering on a signal waveform obtained by one mass scanning. FIG. 5 is a diagram illustrating an example of setting contents of event measurement conditions. FIG. 6 is an explanatory diagram of operations in repeated mass scanning. ↓ in FIG. 6 is the timing of extraction of ions from the ion trap 30, and the hatched portion corresponds to the time range from time t = 0 to t3 shown in FIG.

  Prior to the execution of the LC / MS analysis, the operator inputs and sets analysis conditions such as an analysis end condition and an event measurement condition from the operation unit 44 (step S1). The analysis end condition is an analysis end time based on the analysis start time, or the number of event repetitions described later. The event measurement condition is to set one or more events defined by a combination of parameters such as ionization polarity (positive ionization / negative ionization), measurement mass range, and number of spectrum averaging. Spectrum averaging means that data obtained by one mass scan is accumulated by the number of times of averaging and is divided by the number of times of averaging. Therefore, the number of times of spectrum averaging is synonymous with the number of times of mass scanning. . In the ion trap 30, a mass range that can be held, that is, a maximum measurable mass range (measurable mass range) is determined according to the structure, applied voltage range, and the like. Therefore, the user can set the measurement mass range within the measurable mass range.

  For example, here, it is assumed that two events, event [1] and event [2], are set as shown in FIG. The measurement conditions for event [1] are measurement mass range: 100-1000, ionization polarity: positive, spectrum averaging count: 2, and the measurement conditions for event [2] are measurement mass range: 100-1000, ionization Polarity: negative, spectrum averaging frequency: 3.

  The operator prepares a target sample and gives an instruction to start LC / MS analysis from the operation unit 44 (step S2). Receiving this instruction via the central control unit 43, the analysis control unit 42 injects a target sample into the mobile phase by the injector 13 in the LC unit 1. At the same time, the MS unit 2 starts a mass analysis operation. First, an event to be executed is initialized (step S3), and mass spectrometry is performed according to the measurement conditions set for the first event (event [1] in FIG. 5).

  That is, the data processing unit 40 initializes the profile integration data storage unit 403 and the noise component integration data storage unit 406 (step S4), and also initializes the count value of the number of times of averaging (step S5).

  In the MS unit 2, ions generated by spraying from the ESI nozzle 22 that has received the eluate from the column 14 are temporarily accumulated in the ion trap 30, and are emitted toward the TOF 31 at a predetermined timing. The timing of this emission is t = 0 shown in FIG. The detection data reading unit 401 sets the time t from the ion trap 30 to reach the ion detector 33 and the signal intensity data detected by the ion detector 33 as a set, and sequentially stores them in the detection data storage unit 400. save. Time data and signal intensity data representing a time-of-flight spectrum as shown in FIG. 4 are obtained by one-time ion emission from the ion trap 30 and storage operation of detection data corresponding to the predetermined time (time 0 to t3). Are stored (step S6). Since the measurement mass range is 100-1000, the voltage applied to the ion trap 30 may be adjusted so as to trap only ions in this mass range.

  The profile data read addition processing unit 402 reads profile data in the time range T2 corresponding to the measurement mass range specified in the event measurement condition (in this example, 100-1000) from the detection data storage unit 400, and the profile integrated data storage unit The data already stored in 403 is added and replaced (step S7). In the state in which the profile integrated data storage unit 403 is initialized, the stored data is zero, so that the profile data read from the detected data storage unit 400 is practically stored in the profile integrated data storage unit 403 as it is. Stored.

  On the other hand, the noise component data readout addition processing unit 405 detects, as noise component data, data in a time range in which an ion signal derived from the target sample is not detected, that is, in a range outside the time range T2 corresponding to the measurement mass range. The data is read from the data storage unit 400, added to the data already stored in the noise component integrated data storage unit 406, and replaced (step S8). In the state where the noise component integrated data storage unit 406 is also initialized, the stored data is zero, so that the noise component data read from the detection data storage unit 400 is substantially stored as it is. Stored in the unit 406.

  As shown in FIG. 4, assuming that the flight start time of ions is t = 0, a period T1 immediately before time t1 when ions having the smallest m / z, which is the lower limit of the measurement mass range, reach the ion detector 33 A period T3 from immediately after time t2 when ions having the largest m / z, which is the upper limit of the measurement mass range, reach the ion detector 33 until the data collection end time t3 is a time range corresponding to outside the measurement mass range. is there. Although it depends on the measurement mass range, generally, the period T3 on the rear side has more time margin, so the data of this period T3 may be used as the noise component data. Of course, the data of the period T1 may be used as the noise component data, and the data of both the periods T1 and T3 may be used.

  However, if the actual measurement mass range is close to the measurable mass upper limit, an ion signal derived from the sample may appear in the period T3 due to an unexpected flight delay or the like. If such a signal is processed as a noise component, erroneous noise removal is executed. Therefore, the noise component data read-out addition processing unit 405 excludes noise information when the signal intensity is higher than a predetermined value in order to eliminate the signal intensity when the signal intensity is not considered to be noise. It is advisable to implement a process that ignores. This determination value may be fixed or may be changed adaptively.

  Next, it is determined whether or not the count value of the number of averaging times has reached a preset number of spectrum averaging times for the event currently being executed (step S9). If the number of spectrum averaging is still insufficient, the count value is incremented (step S10), and the process returns to step S6. Through the processing in steps S6 to S10, the integration of the profile data and the noise component data is executed for a predetermined averaging number. In the example of FIG. 5, when the event [1] is executed, the averaging count is “2”, and thus the processing of steps S6 to S10 is repeated twice. This means that, as shown in FIG. 6, the mass scanning of ions having an ionization polarity of “positive” is performed twice. After the predetermined number of integrations, the noise information calculation unit 407 reads the integrated data from the noise component integrated data storage unit 406, and calculates the noise signal magnitude (noise level L) and its variance (standard deviation σ). Calculate as noise information (step S11).

The profile data averaging processing unit 404 obtains an average value by reading the accumulated data stored in the profile integrated data storage unit 403 and dividing by the number of times of averaging. The profile data noise removal processing unit 408 removes a noise component from the averaged profile spectrum (step S12). Specifically, assuming that the averaged profile spectrum is i1 and the profile spectrum after noise removal is i2, the noise level L and the standard deviation σ are used.
(1) When i1 ≧ L + α · σ: i2 = i1−L
(2) When i1 <L + α · σ: i2 = 0
The calculation process is executed. Here, α is a predetermined coefficient, and usually α is set in a range of 3 to 5. The coefficient α may be changed according to a measurement mode such as MS analysis or MS ⁿ analysis. In this example, “L + α · σ” obtained from the noise level L and the standard deviation σ corresponds to the “threshold value” for removing noise components in the present invention.

  If the noise component is removed from the profile spectrum averaged as described above, the data processing unit 40 converts the time information in the profile spectrum into an m / z value, and if necessary, converts the m / z value. A shift correction process or the like is performed to create a mass spectrum (step S13). This mass spectrum information is sent to the central control unit 43 and displayed on the screen of the display unit 45.

  Subsequently, the data processing unit 40 determines whether or not the processing has been completed for the number of events created first (step S14). If not finished yet, the next event is set (step S15) and the process returns to step S4. In the example of FIG. 5, since two events are set, first, processing for event [1] is executed, and when it comes to step S14, since event [2] still remains, it is determined as “NO”. In step S15, event [2] is set, and the process returns to step S4. As a result, the profile integration data storage unit 403 and the noise component integration data storage unit 406 are initialized again, the count value of the averaging count is also initialized, and the processing of steps S6 to S9 is repeated three times that is the averaging count. . Thereafter, the process proceeds to step S11, and a mass spectrum for event [2] is created based on the profile spectrum from which noise has been removed.

  When the process for the event [2] is executed and the process comes to step S14, it is determined as “YES” because the processes of the two events that have been set initially are completed, and the process proceeds to step S16. It is determined whether or not an end condition such as an analysis end time set first has been reached (step S16). If not, the process returns to step S3, and the process is repeated again in order from the first event. Therefore, as shown in FIG. 6, the mass analysis operation and the data processing associated therewith are repeated in the order of event [1] → event [2] → event [1] →.

  In other words, at event [1], mass scanning in which ions generated under positive ion generation conditions are emitted from the ion trap 30, separated by the TOF 31, and detected by the ion detector 33 is repeated twice. It is. After that, the process moves to event [2], and ions generated under negative ion generation conditions are emitted from the ion trap 30, separated by the TOF 31, and detected by the ion detector 33. Is repeated three times. These two events are taken as a set, which is periodically repeated until the analysis end time is reached. Then, if the analysis end time has elapsed, all the processes are ended.

  As described above, in the LC / IT-TOFMS of the present embodiment, both the spectrum information of the measurement mass range and the information of the noise component are obtained for each mass scan, so that the time difference of acquisition can be substantially ignored. It is. Therefore, even if there is a temporal variation in electrical noise in the ion detector 33, the I / V converter 34, and the amplifier 35, it can be accurately removed to obtain a highly accurate mass spectrum.

  It should be noted that the above embodiment is merely an example, and it is obvious that changes and modifications can be made as appropriate within the scope of the present invention.

For example, as described above, the ion trap 30 can cleave a specific ion one or more times, and MS ⁿ analysis for mass analysis of the product ion thus generated can be added to the event measurement conditions.

  The present invention is also applicable to a mass spectrometer using a mass separator other than the time-of-flight mass separator. For example, in a mass spectrometer using a quadrupole mass filter, mass scanning is performed by sweeping an applied voltage to the quadrupole mass filter. Therefore, the data collected when the conditions of the applied voltage at which all mass ions cannot pass can be set as noise component data. Also, instead of a quadrupole mass filter, a condition for shielding all ions in an ion transport optical system such as an ion guide in front of it is set for each mass scan, and data collected under that condition is It may be noise component data.

DESCRIPTION OF SYMBOLS 1 ... Liquid chromatograph (LC) part 11 ... Mobile phase container 12 ... Liquid feed pump 13 ... Injector 14 ... Column 2 ... Mass spectrometry (MS) part 21 ... Ionization chamber 22 ... ESI nozzle 23 ... Desolvation tube 24, 27 ... Intermediate vacuum chambers 25, 28 ... ion guide 26 ... skimmer 29 ... analysis chamber 30 ... ion trap 31 ... time-of-flight mass separator (TOF)
32 ... Reflectron electrode 33 ... Ion detector 34 ... I / V converter 35 ... Amplifier 36 ... A / D converter 40 ... Data processing unit 400 ... Detection data storage unit 401 ... Detection data reading unit 402 ... Addition of profile data reading Processing unit 403 ... Profile integration data storage unit 404 ... Profile data averaging processing unit 405 ... Noise component data read addition processing unit 406 ... Noise component integration data storage unit 407 ... Noise information calculation unit 408 ... Profile data noise removal processing unit 42 ... Analysis control unit 43 ... central control unit 44 ... operation unit 45 ... display unit

Claims (4)

Mass over a predetermined mass range collected by a mass spectrometer comprising an ion source, a mass separator that mass-separates ions generated in the ion source, and a detector that detects the mass-separated ions A data processing method for processing data for creating a spectrum,
a) Noise information that extracts data in a range where ions derived from the sample do not reach the detector from measurement data collected for mass scanning, and performs statistical processing based on the data to calculate a threshold value An acquisition step;
b) Profile data acquisition step for extracting data corresponding to the measurement mass range in the measurement data as profile data;
c) a noise removal processing step of removing a noise component from the profile data using the threshold;
d) a spectrum creation step for creating a mass spectrum using the profile data from which noise has been removed;
A method for processing mass spectrometry data, comprising: An ion source, a mass separator that mass-separates ions generated from the ion source, a detector that detects mass-separated ions, and a mass spectrum that covers the predetermined mass range obtained by the detector A data processing unit for processing measurement data for performing the measurement, wherein the data processing unit includes:
a) Noise information that extracts data in a range where ions derived from the sample do not reach the detector from measurement data collected for mass scanning, and performs statistical processing based on the data to calculate a threshold value Acquisition means;
b) Profile data acquisition means for extracting data corresponding to the measurement mass range in the measurement data as profile data;
c) noise removal processing means for removing a noise component from the profile data using the threshold;
d) spectrum creation means for creating a mass spectrum using the profile data from which noise has been removed;
A mass spectrometer comprising: The mass spectrometer according to claim 2, wherein the mass spectrometer is capable of repeatedly performing mass scanning under a plurality of different analysis conditions,
A condition setting unit that inputs and sets the analysis conditions at the time of mass scanning, and mass scanning of a plurality of conditions with different analysis conditions that are input and set by the condition setting unit is set as one cycle, and each cycle is repeated while repeating this cycle. An analysis control means for collecting corresponding data;
The noise information acquisition means extracts data corresponding to noise from measurement data obtained for each mass scan under each analysis condition.   4. The mass spectrometer according to claim 3, wherein the analysis condition includes a polarity of ions generated by the ion source.

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