JP2013068444A - Comprehensive two-dimensional chromatograph mass analysis data processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve accuracy of component identification by DB search or the like by accurately removing a background superimposed on a mass spectrum which is obtained by comprehensive two-dimensional GC/MS.SOLUTION: A background region is set around a peak region corresponding to a peak detected on a two-dimensional chromatogram, and a background in a position (p, q) of an arbitrary pixel in the peak region is estimated by interpolating a mass spectrum of two pixels positioned within the background region with the position held therebetween. Backgrounds determined, respectively, in directions of two time bases T1 and T2 are averaged and subtracted from the mass spectrum in the pixel of the position (p, q), thereby calculating a mass spectrum from which the background has been removed. Therefore, the background is removed from the mass spectrums in pixels corresponding to a peak, and on the basis of these mass spectrums, a component of the peak is identified.

Description

  The present invention relates to a data processing apparatus for processing data collected by chromatographic mass spectrometry combining a Comprehensive two-dimensional gas chromatograph (GC) and a mass spectrometer (MS), and more particularly, mass spectrometry. The present invention relates to a data processing apparatus that processes mass spectrum data obtained by performing scan measurement in an apparatus.

  As one of GC analysis methods, a method called a comprehensive two-dimensional gas chromatograph (also referred to as “GC × GC”) is known (see Patent Document 1). In the comprehensive two-dimensional GC, various components in a sample are first separated by a first-dimensional column (hereinafter referred to as “primary column”), and the eluted components are introduced into a modulator. The modulator collects the introduced components at regular time intervals (usually about several seconds) and then leaves them with a very narrow time bandwidth and introduces them into the second dimension column (hereinafter referred to as “secondary column”). Repeat the operation. In general, the secondary column has a polarity different from that of the primary column, and a column that can separate a plurality of components that were not sufficiently separated by the primary column at high speed is used. As a result, in the comprehensive two-dimensional GC, sample components with peaks that are not separated in the primary column can be separated in the secondary column, and the separation performance is greatly improved as compared with the normal GC. For this reason, it is very effective for the analysis of a sample containing many components having similar retention times, for example, the analysis of hydrocarbons in diesel fuel.

  In the comprehensive two-dimensional GC, unlike a multi-dimensional (MD) GC using a plurality of detectors, a detection signal is obtained by one detector connected to the outlet of the secondary column. Therefore, it is possible to create a chromatogram similar to a normal GC, that is, a chromatogram in which the horizontal axis is the time axis and the vertical axis is the signal intensity axis, but in general, two columns with different polarities are used. In order to show the state of separation in an easy-to-understand manner, the retention time in the primary column and the retention time in the secondary column are two axes orthogonal to each other, and the signal intensity is expressed by contour lines. A three-dimensional chromatogram with three axes is created. As data processing software for creating such a chromatogram, “GC Image” (see Non-Patent Document 1) provided by ZOEX (USA) is well known.

  FIG. 3B is an example of a two-dimensional contour chromatogram in which the horizontal axis represents the retention time of the primary column and the vertical axis represents the retention time of the secondary column. In the temperature rising analysis, the horizontal axis represents the boiling point order and the vertical axis represents the polar order. Therefore, according to the two-dimensional contour chromatogram, it is easy to understand the properties of each compound, and many Even if a compound is contained, it is possible to easily grasp what kind of compound is contained.

  As a comprehensive two-dimensional GC detector, the same detector as a general GC detector can be used. When analyzing a mixed sample of multiple components, a mass spectrometer (MS) is used as a detector. The comprehensive two-dimensional GC / MS used is useful. When qualitative analysis is performed using comprehensive two-dimensional GC / MS, generally, MS performs scan measurement over a predetermined mass range (strictly, mass-to-charge ratio range), and the mass acquired by the scan measurement is measured. The unknown substance is identified by comparing the peak pattern (or peak list) of the spectrum with the mass spectrum data of the known substance recorded in the library (database).

  In general GC / MS as well as the comprehensive two-dimensional GC / MS, the obtained mass spectrum includes various noise peaks, which becomes an obstacle to the component identification as described above. Therefore, in the case of normal GC / MS, a mass spectrum obtained at a time position where no peak exists on the chromatogram is compared with a mass spectrum obtained at a time position corresponding to the peak appearing in the chromatogram (total ion chromatogram). Data processing is performed such that the spectrum is regarded as background noise and is subtracted.

  On the other hand, a background removal method as described in Non-Patent Document 2 is known for comprehensive two-dimensional GC. In this method, in the two-dimensional chromatogram, the pixel having the minimum signal value in each of the primary column holding time direction and the secondary column holding time direction (the smallest unit of one data on the two-dimensional chromatogram) is found, The background level is estimated by calculating an average value or the like using the signal value of the pixel and the signal value of the adjacent pixel of the pixel, and the background converted into one pixel is used as the signal of each pixel. It is subtracted from the value. The background removal method described in Non-Patent Document 2 aims to improve the quantitativeness based on the chromatogram, and appropriately obtains the peak shape assuming a background that slowly changes over time. I have to.

  Although the background removal method of the conventional comprehensive two-dimensional GC described above can satisfactorily remove the slowly changing background, another peak is very close to the target peak on the two-dimensional chromatogram. If there is a peak, or if another peak overlaps the target peak, the effect of such another peak cannot be removed. In the first place, it is important to obtain parameters such as chromatogram peak area accurately for the purpose of quantitative analysis. Quantitative analysis under conditions where peaks overlap on a two-dimensional chromatogram is common. Is not done.

  On the other hand, qualitative analysis is important especially in a situation where a sample contains various components, and it appears in the mass spectrum as described above in order to enhance qualitativeness based on the results obtained by comprehensive two-dimensional GC / MS. It is important to remove as much noise as possible. In this case, the accuracy of the peak intensity derived from the target component is important. However, in the conventional comprehensive two-dimensional GC background removal method described above, when the peaks are not sufficiently separated on the two-dimensional chromatogram, noise peaks superimposed on the mass spectrum at the appearance time of those peaks are accurately detected. It is difficult to remove.

JP 2011-122822 A

"GC Image GCxGC Software", [online], US Zoex, [searched on September 1, 2011], Internet <URL: http://www.gcimage.com/gcxgc/index.html> Reichenbach and three others, “Image background removal in comprehensive two-dimensional gas chromatography”, Journal Journal of Chromatography A, Vol.985, 2003, p.47-56

  The present invention has been made in view of the above problems, and its object is to accurately remove noise superimposed on mass spectrum data obtained by comprehensive two-dimensional GC / MS, for example, To provide a comprehensive data processing apparatus for two-dimensional chromatograph mass spectrometry capable of improving qualitative performance using mass spectrum data.

In order to solve the above problems, the present invention introduces a sample separated by a comprehensive two-dimensional chromatograph including a primary column, a modulator, and a secondary column into the mass spectrometer, A comprehensive two-dimensional chromatographic mass spectrometry data processing device for processing mass spectral data collected by performing scan measurements that repeatedly scan a predetermined mass range,
a) a two-dimensional chromatogram creating means for creating a two-dimensional chromatogram showing a temporal change in the total ion intensity based on the collected mass spectrum data;
b) a peak detecting means for detecting a peak for the two-dimensional chromatogram;
c) Area determining means for determining a peak area corresponding to the peak detected by the peak detecting means and a background area around the peak area on a plane formed by two time axes of the two-dimensional chromatogram. ,
d) Based on mass spectrum data at a plurality of measurement points in the background region, a mass spectrum background at at least one measurement point in the peak region is estimated, and a mass spectrum obtained by removing the estimated background is calculated. The background removal means sought,
It is characterized by having.

  The “measurement point” is a point on a plane formed by two time axes of a two-dimensional chromatogram indicating a retention time for acquiring mass spectrum data in a predetermined mass range. In a two-dimensional chromatogram created and displayed based on total ion chromatogram (TIC) data, one measurement point indicates one pixel. Therefore, in the following description, a measurement point and a pixel are synonymous.

  In the data processing apparatus for comprehensive two-dimensional chromatograph mass spectrometry according to the present invention, a background region is set around a target peak, more specifically, a peak to be identified, among peaks appearing in a two-dimensional chromatogram. To do. That is, the measurement point in this background area, that is, the holding time is close to the time when the target peak appears, and even if the background changes in a relatively short time, the measurement in the background area It is estimated that the background spectrum at the point and the background superimposed on the mass spectrum at the measurement point corresponding to the target peak have a correlation. Therefore, the background removing unit can accurately estimate the background spectrum superimposed on the mass spectrum at the measurement point corresponding to the target peak, and can obtain the mass spectrum with little influence of the background. .

  In the comprehensive data processing apparatus for two-dimensional chromatograph mass spectrometry according to the present invention, preferably, the background removing means is in the background region on a plane formed by two time axes of the two-dimensional chromatogram. A background reference measurement point is defined on both sides of the measurement point on a straight line including the measurement point corresponding to the target peak, and the target peak is supported based on mass spectrum data of the plurality of background reference measurement points. It is preferable that the background of the mass spectrum at the measurement point to be estimated be estimated. When estimating the mass spectrum background at the measurement points in the peak region based on the mass spectrum data at the plurality of background reference measurement points, for example, the signal intensity at the plurality of background reference measurement points for each mass-to-charge ratio. Should be interpolated. The simplest interpolation is linear interpolation, but polynomial interpolation or weighted interpolation may be performed.

  More preferably, the straight line for determining the background reference measurement point includes two straight lines along two time axes of the two-dimensional chromatogram, and corresponds to the target peak on the two or more straight lines. A configuration may be adopted in which the background at the measurement point corresponding to the target peak is estimated based on the mass spectrum data of four or more background reference measurement points respectively defined on both sides of the measurement point.

  According to this configuration, a measurement point that is close in time to the target peak on the separation characteristic of the primary column and a measurement point that is close in time to the target peak on the separation characteristic of the secondary column are used as background reference measurement points. Since the interpolation is performed in the directions along the two time axes, the background spectrum superimposed on the mass spectrum at the measurement point corresponding to the target peak can be estimated more accurately. Thereby, the accuracy of background removal is also improved.

  According to the comprehensive data processing apparatus for two-dimensional chromatograph mass spectrometry according to the present invention, the background caused by disturbances generated in a relatively short period of time as well as due to factors that slowly change over time is provided. A properly removed mass spectrum can be acquired. In addition, when a part of another peak overlaps the target peak in the two-dimensional chromatogram, the other peak also partially enters the background region, so the overlapping part of another peak is also used as the background. The purity of the mass spectrum at the target peak can be increased. Thereby, the accuracy of component identification using a mass spectrum is improved.

The schematic block diagram of one Example of comprehensive two-dimensional GC / MS provided with the data processing apparatus which concerns on this invention. The flowchart of the qualitative process operation | movement in comprehensive two-dimensional GC / MS of a present Example. The figure which shows an example of the two-dimensional contour-line chromatogram created in comprehensive two-dimensional GC / MS of a present Example. Explanatory drawing of the background removal process of the mass spectrum in comprehensive two-dimensional GC / MS of a present Example. Explanatory drawing of the background removal process of the mass spectrum in comprehensive two-dimensional GC / MS of a present Example. Explanatory drawing of the other Example of the background removal process of a mass spectrum.

  An embodiment of a comprehensive two-dimensional GC / MS using the comprehensive two-dimensional chromatographic mass spectrometry data processing apparatus according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram of a comprehensive two-dimensional GC / MS according to this embodiment.

  The analysis unit 1 collects a component (compound) eluted from the sample introduction unit 11 and the primary column 12 including a primary column 12 and a sample vaporization chamber for introducing a sample gas into the primary column 12 at regular time intervals. The time-compressed modulator 13 and the primary column 12 are separated by a high-speed separable secondary column 14 having two different separation characteristics (typically different polarities) and the two-stage columns 12 and 14. And a mass spectrometer 15 for detecting each component. The mass spectrometer 15 is a quadrupole mass spectrometer using a quadrupole mass filter as a mass analyzer, and can perform scan measurement that repeatedly scans a specified mass range.

  The operation of each unit included in the analysis unit 1 is controlled by the analysis control unit 200 included in the control / processing unit 2. The data processing unit 20 included in the control / processing unit 2 has a function of processing data acquired by the mass spectrometer 15 and identifying various components included in the sample (that is, qualitative analysis). More specifically, the data processing unit 20 includes a data storage unit 21 that stores mass spectrum data sequentially obtained with time, a chromatogram creation unit 22 that creates a two-dimensional chromatogram based on the mass spectrum data, A peak detector 23 for detecting a peak on the two-dimensional chromatogram, a region extractor 24 for determining a peak region and a background region on the two-dimensional chromatogram based on the peak detection result, and a mass spectrum A background removal unit 25 for removing the superimposed background, a processed data storage unit 26 for storing the mass spectrum data from which the background has been removed, and identification information in which peak information of the mass spectrum is recorded for each compound. Database 28 and background removed Including functional blocks, such as component identification unit 27 for component identification, with reference to the identification database 28 using mass spectral data.

  An operation unit 3 and a display unit 4 as a user interface are connected to the main control unit 201 included in the control / processing unit 2. The main control unit 201, analysis control unit 200, and data processing unit 20 are realized by using a personal computer as a hardware resource and executing dedicated control / processing software installed in the personal computer in advance. can do.

  First, an analysis operation in the analysis unit 1, that is, a data collection operation will be schematically described. In the analysis unit 1, the sample introduction unit 11 introduces a sample to be analyzed into a carrier gas that is sent to the primary column 12 at a substantially constant flow rate in response to an instruction from the analysis control unit 200. This sample usually contains a number of components (compounds). Various components contained in the sample are separated while passing through the primary column 12 that has been temperature-controlled according to a predetermined temperature raising program, and are eluted with a time lag. At this point in time, not all components are sufficiently separated, and the components having similar retention times in the primary column 12 are overlapped (in a mixed state) and eluted.

  The modulator 13 collects all the components eluted from the primary column 12 during a certain time (= modulation period t: generally several seconds to at most about 10 seconds), compresses them in time, and sends them to the secondary column 14. , Is repeated continuously. Therefore, the eluted component from the primary column 12 is sent to the secondary column 14 without leakage. A plurality of sample components sent in every modulation period t are separated and eluted in the time direction with high resolution when passing through the secondary column 14, and are introduced into the mass spectrometer 15 in the order of elution. When the scan measurement is executed in the mass spectrometer 15, mass spectrum data over a predetermined mass range is obtained at every interval interval of the scan measurement. By performing scan measurement at intervals shorter than the time width during which each component is eluted from the secondary column 14, all the eluted components can be detected without omission. Thus, the mass spectrum data repeatedly acquired by the mass spectrometer 15 is stored in the data storage unit 21.

  Next, a qualitative processing operation including a background removal process, which is a feature of the comprehensive two-dimensional GC / MS of the present embodiment, will be described in detail with reference to FIGS. FIG. 2 is a flowchart of this qualitative processing operation, FIG. 3 is a diagram showing an example of a two-dimensional chromatogram, and FIGS. 4 and 5 are explanatory diagrams of background removal processing for a mass spectrum.

  In the data processing unit 20, the chromatogram creation unit 22 adds the intensity signals of all ions that do not depend on the mass-to-charge ratio to the mass spectrum data collected as described above for each mass spectrum. The total ion chromatogram (TIC) data is obtained by arranging them. Then, the TIC data is divided every modulation period t, and as shown in FIG. 3A, the data in the modulation period t are sequentially arranged in the vertical axis (T2 axis) direction and modulated in the horizontal axis (T1 axis) direction. A two-dimensional chromatogram as shown in FIG. 3B is created by arranging the generation order of the periods t and expressing the signal intensity with contour lines (or color differences) (step S1). This two-dimensional chromatogram is displayed on the screen of the display unit 4 via the main control unit 201.

  The two-dimensional chromatogram is a set of rectangular pixels each having a time width corresponding to the modulation period t in the horizontal axis direction and the interval interval T of the scan measurement in the vertical axis direction. Mass spectrum data of a predetermined mass range exists for each pixel, and each pixel shows one TIC data on the two-dimensional chromatogram.

  The peak detection unit 23 performs peak detection two-dimensionally on the two-dimensional chromatogram (step S2). The algorithm for peak detection is not particularly limited, and for example, it can be the same as the peak detection on a normal one-dimensional chromatogram. For example, the intensity value is monitored according to the time axis, and when the slope of the rising curve of the intensity value exceeds a predetermined value, it is regarded as the peak start point, the inclination further decreases from zero, and the absolute value becomes a predetermined value. A peak is detected by regarding it as the peak end point when: By performing this on each of the two time axes, the two-dimensional peak range and peak top position can be determined.

  If a peak is detected on the two-dimensional chromatogram, a peak to be processed, that is, a qualitative target is selected (step S3). When this peak selection is performed automatically, for example, a predetermined number of peaks or higher than a predetermined intensity may be selected in order of increasing peak top intensity. It is also possible to perform manual peak selection by user designation instead of automatic. In that case, the detected peak may be clearly indicated on the two-dimensional chromatogram displayed on the display unit 4, and the user may instruct the peak to be qualitated by the operation unit 3 by clicking or the like.

  When the peak to be processed is determined, the region extraction unit 24 first determines the range where one of the peaks to be processed exists in the two-dimensional chromatogram, and sets a background region around the peak region. (Step S4). In this example, as shown in FIG. 4, when it is determined that a pixel indicated by diagonal lines on the two-dimensional chromatogram is a peak region, the background region is set to the smallest rectangular frame shape surrounding it. That is, a plurality of linear pixels in the direction along both time axes T1 and T2 between the outer rectangular frame and the inner rectangular frame become the background region. However, the shape of the background region is not limited to this, and may be any shape as long as it surrounds the peak region (not necessarily surrounding the entire circumference) and is close to the outside of the peak region. be able to.

  The mass spectrum in each pixel included in the peak region is a mass spectrum to be subject to background removal, while the mass spectrum in each pixel included in the background region is the background spectrum used for background removal. It is a mass spectrum which becomes original data for calculation.

  The background removal unit 25 estimates the background superimposed on the mass spectrum of the arbitrary pixel in the peak region from the mass spectra of a plurality of pixels in the background region corresponding to the pixel. (Step S5). An example of the estimation method will be described with reference to FIG. 4 and 5 are simplified diagrams for easy understanding of the description. In many cases, the peak region includes a larger number of pixels.

Now, it is assumed that the rectangular region surrounded by the outer frame of the background region includes m pixels in the T1 direction and n pixels in the T2 direction. The position of the pixel in this region is represented by (i, j), where 1 ≦ i ≦ m and 1 ≦ j ≦ n. Further, in the mass spectrum data for the pixel located at (j, i), the signal intensity of the mass to charge ratio m / z = k is represented by I ^k _ij . Consider a case where the background removal of the mass spectrum corresponding to any one pixel existing at the position (p, q) in the peak region is executed.

Consider a straight line extending in the T1 axis direction at the position of q, that is, a pixel line arranged in a straight line in the T1 axis direction and including two pixels included in both ends thereof, that is, in the background area. Extract pixels. In the example of FIG. 5, the two pixels exist at the position (1, q) and the position (m, q). The two pixels existing at the positions (1, q) and (m, q) and the pixel at the position (p, q) in the peak region are quite close in time on the separation characteristics of the primary column 12. . Further, the position (1, q) is earlier in time than the position (p, q), and the position (m, q) is later in time than the position (p, q). Therefore, in the mass spectrum data for the pixel at the position (p, q) in the peak region, the signal intensity I ^k _pq of m / z = k has the position (1, q) and the position (m, q). It can be considered that the signal intensities obtained by interpolating m / z = k signal intensities I ^k _1q and I ^k _mq in the mass spectrum data for the pixels existing in are superimposed as a background. As shown in the right part of FIG. 5, if it is approximated that the influence of the background changes linearly with time, it exists between (1, q) and (m, q) by interpolation by linear interpolation. Any pixel background can be calculated. That is, the background for the pixel at the position (p, q) when considering the temporal change in the T1 axis direction is
_{^{X k pq = (I k mq}} -I k 1q) (p / m) + I k 1q
It is.

On the other hand, similarly, consider a pixel line that includes a pixel extending in the T2 axis direction at the position p, that is, a pixel existing at the position (p, q), and is aligned in the T2 axis direction. 2 pixels are extracted. In the example of FIG. 5, the two pixels exist at the position (p, 1) and the position (p, n). The two pixels existing at the positions (p, 1) and (p, n) and the pixel at the position (p, q) in the peak region are quite close in time on the separation characteristics of the secondary column 14. . Further, the position (p, 1) is temporally before the position (p, q), and the position (p, n) is temporally after the position (p, q). Therefore, in the mass spectrum data for the pixel at the position (p, q) in the peak region, the signal intensity I ^k _pq at m / z = k has the position (p, 1) and the position (p, n). It can be considered that the signal intensities obtained by interpolating the signal intensities I ^k _p1 and I ^k _pn of m / z = k in the mass spectrum data for the pixels existing in are superimposed as the background. Also in this case, since the background of an arbitrary pixel existing between (p, 1) and (p, n) can be calculated by interpolation by linear interpolation, when the temporal change in the T2 axis direction is taken into consideration The background for the pixel at position (p, q) is
_{^{Y k pq = (I k pn}} -I k p1) (q / n) + I k p1
It is.

Since it can be considered that the influence of the T1 axis direction and the T2 axis direction appears on average in the pixel at the position (p, q), the background of m / z = k in the pixel at the position (p, q) The strength of
^{_{B k pq = (X k pq}} + Y k pq) / 2
It is estimated that. By performing the same estimation for all the mass-to-charge ratios m / z in the mass spectrum, the background spectrum B _pq at the pixel at the position (p, q) can be obtained.

When the background spectrum B _pq is obtained as described above, the background spectrum B _pq is subtracted from the mass spectrum I _pq for the pixel at the position (p, q), that is, the signal intensity is subtracted for each mass to charge ratio. Thus, the mass spectrum S _pq from which the background has been removed is obtained, and the mass spectrum data thus obtained is stored in the processed data storage unit 26 (step S6).

  If there is an unprocessed pixel in the peak region of the peak to be processed, the process returns from step S7 to S5, and the above-described steps S5 and S6 are performed on another unprocessed pixel to obtain the back Find the mass spectrum with the ground removed. Actually, the background removal for the mass spectrum of all the pixels included in the peak region is efficiently advanced by proceeding with the processing in order from the smallest i and j at the position (i, j) for the pixels in the peak region. be able to.

  However, it is not always necessary to remove the background of the mass spectrum for all the pixels included in the peak region. That is, when only the mass spectrum near the peak top appearing in the two-dimensional chromatogram for component identification described later is used, the background of only the mass spectrum near the peak top may be removed. On the other hand, when it is necessary to create a two-dimensional chromatogram based on the signal intensity for a specific mass-to-charge ratio, it is necessary to perform background removal at least for all pixels in the peak region for that mass-to-charge ratio.

  When the processing is completed for all the pixels in the peak area of one peak, it is determined whether or not there is an unprocessed peak among the processing target peaks selected in step S3 (step S8). If there is a processing peak, the process returns to step S4, and the processing in steps S4 to S7 described above for another peak is repeated. This removes the background superimposed on the mass spectrum for all peaks selected either automatically or manually.

  Thereafter, the component identification unit 27 reads the mass spectrum data from which the background has been removed from the processed data storage unit 26, and performs component identification by database search using this mass spectrum (step S9). Specifically, for example, for one peak detected from a two-dimensional chromatogram, an average or integration of mass spectra obtained from the peak region is obtained, and a peak pattern similar to the average or peak pattern of the integrated mass spectrum is obtained. A component corresponding to each peak is identified by searching the indicated database 28 in the identification database 28.

  As described above, in the comprehensive two-dimensional GC / MS of this embodiment, the background superimposed on the mass spectrum corresponding to the peak appearing in the two-dimensional chromatogram is at a time very close to the appearance time of the peak. It is removed using the resulting background spectrum. In particular, a background spectrum that is close to the target peak appearance time in both the time direction of separation by the primary column 12 and the time direction of separation by the secondary column 14, more specifically, the background spectrum before and after the peak appearance time is removed. Therefore, not only due to factors that change slowly over time, but also backgrounds caused by disturbances that occur in a relatively short time are accurately removed. As a result, the accuracy of component identification is improved, and the probability of occurrence of missing or incorrect identification can be reduced.

  Further, in the comprehensive two-dimensional GC / MS of the present embodiment, when a peak to be processed and a part of another peak overlap in the two-dimensional chromatogram, the other peak is partially background region. Will enter. Therefore, most of the overlapping portions of other peaks are removed as background. However, in order to reduce such overlapping of adjacent peaks as a background, as described above, a certain pixel is obtained by using a mass spectrum in pixels located on the respective straight lines in the T1 axis direction and the T2 axis direction. In addition to estimating the background spectrum, it is desirable to use the mass spectrum of other pixels.

Specifically, as shown in FIG. 6A, when a peak to be processed and an adjacent peak partially overlap on the two-dimensional chromatogram, as shown in FIG. T2) The background may be estimated as described above using a mass spectrum of pixels located on a line extending at an angle of 45 ° with respect to the axis and extending in an oblique direction. When the background thus estimated is also reflected in the B _pq , the peak overlap portion shown in FIG. 6A is regarded as the background and appropriately removed.

  In the description of the above embodiment, the background at the pixel position corresponding to the target peak is estimated by linear interpolation using the mass spectrum of the pixels in the background region. Polynomial interpolation or weighted interpolation may be performed for estimation. In addition, when a peak exists in isolation on the two-dimensional chromatogram, when adjacent peaks overlap as shown in FIG. 6A, or when another peak is present in a certain peak region. The background estimation method may be changed as appropriate when it is completely included (when another sharp peak is superimposed on the tailing of a peak greatly expanded due to various factors). Similarly, the background region setting method may be changed as appropriate according to the peak situation.

  Further, the above-described embodiment is merely an example of the present invention, and other than the above-described various modifications, any appropriate modification, correction, or addition within the spirit of the present invention is included in the scope of the claims of the present application. Is clear.

DESCRIPTION OF SYMBOLS 1 ... Analysis part 11 ... Sample introduction part 12 ... Primary column 13 ... Modulator 14 ... Secondary column 15 ... Mass spectrometer 2 ... Control and processing part 200 ... Analysis control part 201 ... Main control part 20 ... Data processing part 21 ... Data storage unit 22 ... chromatogram creation unit 23 ... peak detection unit 24 ... area extraction unit 25 ... background removal unit 26 ... processed data storage unit 27 ... component identification unit 28 ... identification database 3 ... operation unit 4 ... display unit

Claims (3)

A sample separated by a comprehensive two-dimensional chromatograph including a primary column, a modulator, and a secondary column is introduced into a mass spectrometer, and scan measurement is performed by repeatedly scanning a predetermined mass range in the mass spectrometer. Comprehensive two-dimensional chromatographic mass spectrometry data processing device for processing mass spectral data collected by
a) a two-dimensional chromatogram creating means for creating a two-dimensional chromatogram showing a temporal change in the total ion intensity based on the collected mass spectrum data;
b) a peak detecting means for detecting a peak for the two-dimensional chromatogram;
c) Area determining means for determining a peak area corresponding to the peak detected by the peak detecting means and a background area around the peak area on a plane formed by two time axes of the two-dimensional chromatogram. ,
d) Based on mass spectrum data at a plurality of positions in the background region, a background of a mass spectrum at at least one position in the peak region is estimated, and a mass spectrum from which the estimated background is removed is obtained. Ground removal means,
A data processing apparatus for comprehensive two-dimensional chromatograph mass spectrometry, comprising: A comprehensive data processing apparatus for two-dimensional chromatograph mass spectrometry according to claim 1,
The background removal means is arranged on both sides of the measurement point on a straight line including a measurement point corresponding to a target peak in the background region on a plane formed by two time axes of the two-dimensional chromatogram. A comprehensive two-dimensional system characterized in that a background reference measurement point is defined, and a mass spectrum background at a measurement point corresponding to the target peak is estimated based on mass spectrum data of the plurality of background reference measurement points. Data processing device for chromatographic mass spectrometry. A comprehensive data processing apparatus for two-dimensional chromatograph mass spectrometry according to claim 2,
The straight line for defining the background reference measurement point includes two straight lines along two time axes of the two-dimensional chromatogram, and sandwiches the measurement point corresponding to the target peak on the two or more straight lines. Comprehensive two-dimensional chromatographic mass analysis data characterized by estimating the background at the measurement point corresponding to the target peak based on the mass spectrum data of four or more background reference measurement points respectively defined on both sides Processing equipment.

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