JP5786703B2 - Data processor for chromatograph mass spectrometer - Google Patents

Description

  The present invention relates to a data processing apparatus that analyzes and collects data collected by a chromatographic mass spectrometer such as a liquid chromatograph mass spectrometer (LC / MS), and more specifically, the presence or absence of multivalent ions derived from a target compound. The present invention relates to a data processing apparatus suitable for determining based on data detected by a quadrupole mass spectrometer.

  An atmospheric pressure ionization interface is used to ionize and analyze a component to be analyzed in a liquid sample or an eluate separated by a liquid chromatograph. As typical atmospheric pressure ionization methods, an electrospray ionization method (ESI), an atmospheric pressure chemical ionization method (APCI), and the like are known. In general, such an atmospheric pressure ionization interface is often used in combination with a quadrupole mass spectrometer, an ion trap mass spectrometer, or a time-of-flight mass spectrometer.

  The atmospheric pressure ionization interface, particularly the ESI interface, has a characteristic that it is easy to generate multivalent ions having a plurality of charges in the process of ionizing a compound. Multivalent ions have an advantage that the mass-to-charge ratio of the ion to be analyzed can be relatively low because the mass-to-charge ratio m / z is smaller than the molecular weight of the original compound depending on the valence. There is. In particular, when analyzing high molecular weight compounds such as proteins and peptides, the mass-to-charge ratio of monovalent ions may exceed the measurable range of the mass spectrometer. It can be within the measurable range of the mass spectrometer. For these reasons, mass spectrometry using multivalent ions is very effective in identifying high molecular weight compounds.

  When a high molecular weight compound is ionized with an ESI ion source and subjected to mass spectrometry, peaks derived from ions of various valences appear in the mass spectrum (for example, see Fig. 1 of Non-Patent Document 2). When mass processing is performed on a mass spectrum in which a plurality of multiply charged ion peaks are observed by a technique called deconvolution, a neutral mass spectrum is obtained (for example, see Fig. 2 of Non-Patent Document 2). From this, the molecular weight of the target compound can be obtained (see Patent Document 1, Non-Patent Document 1, etc.).

The above-described conventional method using deconvolution is useful when a large number (usually about 10 or more) of multivalent ions having different valences derived from the target compound are observed on the mass spectrum. It is possible to determine the molecular weight with high accuracy. However, when there are only about two to three types of multivalent ion peaks on the mass spectrum, the technique using deconvolution is not very effective. This is because it corresponds to a multivalent ion on the mass spectrum, that is, when the molecular weight of the compound is M, the valence of the ion is n, the molecular weight of the proton is H, and the mass-to-charge ratio m / z of the observed ion is m. In addition, when there are only about 2 to 3 peaks corresponding to the following formula (1), the peaks may not coincide with the target compound but may coincide with each other.
M = n (m + H) (1)
In particular, when the intensity of some ion peaks is low, it is difficult to distinguish them from noise peaks, etc., and it is determined from the mass spectrum whether these multiple ion peaks are derived from the same target compound. It is quite difficult to do.

US Pat. No. 5,130,538

"[Technical classification] 2-2-3-1 General mass spectrometry technology / Ion species / Assignment, Identification / Multivalent ion [Technical name] 2-2-3-1-1 Multivalent ion", [online], Patent Agency, [Search on November 17, 2011], Internet <URL: http://www.jpo.go.jp/shiryou/s_sonota/hyoujun_gijutsu/mass/2-2-3.pdf> "Shimadzu Application News No. C55 Analysis of Proteins and Peptides by LC-MS", [online], Shimadzu Corporation, [Searched on November 17, 2011], Internet <URL: http: //www.imtakt. com / jp / Support / UserReport / Shimadzu / LCMS / c55-CD0peptide.pdf>

  The present invention has been made to solve the above-mentioned problems, and the object of the present invention is to coincide accidentally even when the number of multivalent ions generated from the target compound is small. Eliminating the effects of undesired peaks, for example, creating a highly accurate neutral mass spectrum of the target compound or determining the molecular weight of the target compound with high accuracy. It is an object of the present invention to provide a data processing apparatus for a chromatograph mass spectrometer that can quickly determine the presence or absence of multivalent ions.

The 1st invention made in order to solve the said subject is the data for chromatograph mass spectrometers which analyze the data about the polyvalent ion derived from the target compound collected by chromatograph mass spectrometers, such as LC / MS In the processing device,
on the mass spectrum obtained in the vicinity of the retention time of a) the subject compound by extracting a plurality of candidate multivalent ion peaks having different valences for the same molecular weight is estimated to be derived from the same compound, the target compound Multivalent ion candidate extraction means for obtaining a plurality of candidate combinations of derived multivalent ion peaks,
b) For each of a plurality of multivalent ion peak candidates included in each of a plurality of combination candidates obtained by the multivalent ion candidate extraction means, create a mass chromatogram at least in the time range near the retention time of the target compound Means for creating a mass chromatogram;
c) In order to select highly reliable combination candidates from the plurality of combination candidates obtained by the multivalent ion candidate extraction means, each of the plurality of combination candidates is created by the mass chromatogram creation means. Further, a display means for displaying a plurality of mass chromatograms for a plurality of multivalent ion peak candidates included in one combination candidate on the same screen,
It is characterized by having.

Further, the second invention made to solve the above problems is for a chromatograph mass spectrometer for analyzing data on multivalent ions derived from a target compound collected by a chromatograph mass spectrometer such as LC / MS. In a data processing device,
on the mass spectrum obtained in the vicinity of the retention time of a) the subject compound by extracting a plurality of candidate multivalent ion peaks having different valences for the same molecular weight is estimated to be derived from the same compound, the target compound Multivalent ion candidate extraction means for obtaining a plurality of candidate combinations of derived multivalent ion peaks,
b) For each of a plurality of multivalent ion peak candidates included in each of a plurality of combination candidates obtained by the multivalent ion candidate extraction means, create a mass chromatogram at least in the time range near the retention time of the target compound Means for creating a mass chromatogram;
c) For each of a plurality of combination candidates obtained by the multivalent ion candidate extraction means, a plurality of masses for a plurality of multivalent ion peak candidates included in one combination candidate created by the mass chromatogram creation means. based on the chromatogram, that they multivalent ion peaks candidate determining whether a multivalent ion peaks originating from the target compound, a candidate determination means for selecting a reliable combination candidates,
It is characterized by having.

  When mass chromatograms are created for multiple types of multivalent ions derived from the same compound and having different valences, a chromatogram peak should appear in the vicinity of the time when the target compound appears (that is, retention time). The shape of the chromatogram peak should be similar. On the other hand, if a peak derived from noise or another compound accidentally exists at the position (mass-to-charge ratio) where a multivalent ion peak appears in the mass spectrum, a mass chromatogram at that mass-to-charge ratio is created. However, no chromatogram peak should appear near the retention time of the target compound. In the data processor for a chromatograph mass spectrometer according to the first and second inventions, this is used to evaluate whether or not the multivalent ion peak candidate obtained from the mass spectrum is derived from the target compound. . In the first invention, by displaying a mass chromatogram corresponding to a multivalent ion peak candidate, an environment in which the user can select an appropriate combination candidate visually (that is, the most likely multivalent ion derived from the target compound). I will provide a. On the other hand, in the second invention, instead of the user himself / herself judging, the candidate judging means automatically evaluates the mass chromatogram and selects an appropriate combination candidate.

In the data processing apparatus for a chromatograph mass spectrometer according to the first and second inventions, the candidate for multivalent ion extraction means, for example, the above (1) assuming a certain molecular weight from the mass spectrum near the retention time of the target compound. ) A plurality of peaks corresponding to the formula are extracted as multivalent ion peak candidates. When the approximate molecular weight of the target compound is known, the predetermined molecular weight range centered on the known molecular weight is limited by the equation (1), and the valence is changed within the predetermined allowable error range. What is necessary is just to search for a valence ion peak candidate. In addition, even if the molecular weight of a compound is unknown, the user can set the molecular weight range and valence range that the compound can take in light of technical common sense. Can be searched. Then, determine a plurality of combination candidates including a plurality of types of multivalent ion peaks candidates differ same compound derived from (i.e. for the same molecular weight) valence.

  The mass chromatogram creating means creates a mass chromatogram in a predetermined time range near the retention time of the target compound, for example, for a plurality of multivalent ion peaks included in the combination candidates obtained from the mass spectrum. In the first invention, the display means displays a plurality of mass chromatograms for a plurality of multivalent ion peak candidates included in one combination candidate on the same screen. As a result, the user can easily compare visually the peak shapes of the mass chromatograms of candidate multivalent ions appearing near the retention time of the target compound, and determine whether or not they can be regarded as multivalent ions derived from the same compound. Can be judged. On the other hand, in the second invention, the candidate determining means confirms the presence of a chromatogram peak near the retention time of the target compound on, for example, a mass chromatogram of candidate multivalent ions, and if the peak shapes are similar, the combination It is determined that the multivalent ion peak included in the candidate is highly likely to be a true multivalent ion peak derived from the target compound. If a combination of a plurality of multivalent ion peaks derived from the target compound is obtained in this way, a neutral spectrum of the target compound or a precise molecular weight can be obtained from this.

  As described above, if all of the plurality of multivalent ion peak candidates included in one combination candidate are true multivalent ion peaks, the reliability of the combination is considered high. However, when the intensity | strength of the some multivalent ion peak candidate contained in one combination candidate is low, the possibility that the peak which does not originate in a target compound corresponded accidentally cannot be denied.

  Therefore, as a preferred aspect of the data processor for the chromatograph mass spectrometer according to the first and second inventions, the multivalent ion candidate extracting means has a signal intensity on the mass spectrum obtained near the retention time of the target compound. The combination candidate may be selected on condition that at least one relatively large peak or peaks is included.

  As a result, for example, at least a part of false multivalent ion peaks due to accidental coincidence of mass-to-charge ratio due to noise or the like can be removed, so that the number of combination candidates is suppressed and the burden of determination work by the user is reduced. Can be reduced. Alternatively, the accuracy in automatically selecting a proper combination can be increased.

  According to the data processor for a chromatograph mass spectrometer according to the present invention, the presence of multiply charged ions can be detected quickly and reliably even when only a few kinds of multiply charged ions derived from the target compound can be observed. It is possible to determine the molecular weight of the target compound with high accuracy by creating a highly accurate neutral mass spectrum.

The block diagram of the principal part of LC / MS which is one Example of the chromatograph mass spectrometer using the data processor which concerns on this invention. The flowchart of multivalent ion data processing in LC / MS of a present Example. Explanatory drawing of the multivalent ion data processing in LC / MS of a present Example. Explanatory drawing of the screen which displays the multivalent ion data processing result in LC / MS of a present Example. The figure which shows an example of the display of a multivalent ion data processing result.

An embodiment of LC / MS using a data processing apparatus according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a configuration diagram of a main part of the LC / MS of this embodiment.
This LC / MS is roughly divided into a liquid chromatograph (LC) 10 and a mass spectrometer (MS) 20, and an atmospheric pressure ionization interface connecting the LC 10 and the MS 20 includes an electrospray ionization (ESI) interface. Face is used.

  In the LC 10, 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 into the mobile phase by the injector 13, the sample is introduced into the column 14 along the flow of the mobile phase. While passing through the column 14, various compounds in the sample are separated from each other, eluted from the outlet of the column 14 at a time lag, and introduced into the MS 20.

  The MS 20 includes an ionization chamber 21 that is maintained in an atmospheric pressure atmosphere, and an analysis chamber 24 that is evacuated by a turbo molecular pump (not shown) and maintained in a high vacuum atmosphere. A first intermediate vacuum chamber 22 and a second intermediate vacuum chamber 23 that are maintained at a high degree of vacuum are disposed. The ionization chamber 21 and the first intermediate vacuum chamber 22 communicate with each other via a small-diameter desolvation tube 26, and the first intermediate vacuum chamber 22 and the second intermediate vacuum chamber 23 are the top of a conical skimmer 28. Communicating through a small-diameter orifice drilled in.

  When the eluate containing various compounds supplied from the LC 10 reaches the ESI nozzle 25 as an ion source, the eluate is given an electric charge by a direct current high voltage applied from a high voltage power source (not shown). 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. In this process, the sample molecules are ionized. The fine droplets containing the generated ions are drawn into the desolvation tube 26 due to the pressure difference, and desolvation further proceeds while passing through the desolvation tube 26 to generate ions. As described above, when high molecular compounds such as proteins are ionized by ESI, not only monovalent ions having a valence of 1, but also various polyvalent ions having a valence of 2 or more are generated. To do.

  The ions thus generated pass through the two intermediate vacuum chambers 22 and 23 while being converged by the ion guides 27 and 29, respectively, and are sent to the analysis chamber 24. In the analysis chamber 24, a quadrupole mass filter 30 and a detector 31 are arranged, and the quadrupole mass filter 30 selectively selects only ions having a specific mass-to-charge ratio among various introduced ions. To pass through. Passed ions reach the detector 31 and are detected, and the detector 31 outputs a current corresponding to the number of reached ions as a detection signal. Since the mass-to-charge ratio of ions passing through the quadrupole mass filter 30 depends on the voltage applied to the filter 30, the ions passing through the quadrupole mass filter 30 are scanned by scanning the applied voltage within a predetermined range. The mass to charge ratio can be scanned.

  A detection signal from the detector 31 is input to the data processing unit 40, first converted into digital data by the data collection unit 41, and temporarily stored in a storage device such as a memory. The multivalent ion data analysis processing unit 42 appropriately reads data stored in the storage device in the data collection unit 41, and executes analysis processing for acquiring information on the target compound to be analyzed as described later. In addition, the analysis control unit 50 controls the operation of each unit of the LC 10 and the MS 20 in order to execute LC / MS analysis based on an instruction from the central control unit 51.

  An input unit 52 and a display unit 53 as a user interface are connected to the central control unit 51, and various commands for analysis are received in response to a user operation by the input unit 52, the analysis control unit 50 and the data processing unit 40. And the obtained analysis result is output to the display unit 53. Note that some or most of the functions of the central control unit 51, the analysis control unit 50, and the data processing unit 40 can be realized by executing predetermined control / processing software on a personal computer.

  In the LC / MS, under the control of the analysis control unit 50, the scan measurement over a predetermined mass-to-charge ratio range is repeatedly executed in the MS 20 from the time when the sample is injected into the mobile phase by the injector 13 in the LC 10. Thereby, the data collection unit 41 stores three-dimensional data having three dimensions of time, mass-to-charge ratio m / z, and signal intensity (ion intensity). The multiply-charged ion data analysis processing unit 42 performs the following characteristic processing on the data thus collected.

  FIG. 2 is a flowchart of multivalent ion data processing in the LC / MS of the present embodiment, FIG. 3 is an explanatory diagram of this multivalent ion data processing, and FIG. 4 is an explanatory diagram of a screen for displaying the multivalent ion data processing results. FIG. 5 is a diagram illustrating an example of a display of multivalent ion data processing results.

  Prior to the execution of processing, the user generates the target compound retention time, the estimated molecular weight (or known approximate molecular weight) or molecular weight range of the target compound from the input compound 52 as parameters necessary for analysis. The valence range of the multiply charged ions, the relative intensity threshold for selecting the multiply charged ions, and the like are input (step S1). Although it is not essential to input the estimated molecular weight or the molecular weight range or the valence range, the number of combination candidates described later can be reduced by inputting these, and the work and operation by the user can be reduced.

  When the substantial analysis process is started, the multivalent ion data analysis processing unit 42 first calculates a total ion chromatogram (or a peak signal with the maximum signal intensity in the mass spectrum at each time) based on the collected data. Base peak chromatogram (intensity arranged in time direction) is created, a peak near the retention time of the target compound is extracted from the chromatogram, and the actual observation of the target compound is retained from the time when the peak top of the peak appears. Time T is calculated (step S2). Next, mass spectrum data (profile data) at the retention time T is acquired (step S3), and a centroid process is performed on the profile data to obtain a mass spectrum in which each peak is indicated by a straight line. Create (step S4). Before performing the centroid processing, it is preferable to remove unnecessary peaks by executing baseline subtraction processing, smoothing processing, or other noise removal processing.

Next, a peak is extracted from the centroided mass spectrum, and the mass-to-charge ratio m / z = m of each peak is obtained. The mass-to-charge ratio m is applied to the formula (1) shown below, and combinations of multivalent ion peaks each having a mass-to-charge ratio m for two or more different ionic valences n for the same molecular weight are combined as candidates. (Step S5).
M = n (m + H) (1)
When the estimated molecular weight M ′ is given in step S1, the molecular weight M in the above formula (1) is limited to the range of M ′ ± ΔM (ΔM is appropriately determined in advance), and the estimated molecular weight range is given. In such a case, M in the above formula (1) may be limited to the estimated molecular weight range. Further, if neither the estimated molecular weight nor the molecular weight range is given, M may be limited within a predetermined default molecular weight range. If a valence range is specified in step S1, n in the above equation (1) may be limited to the valence range. That is, the narrower the range of the molecular weight M in the above formula (1) and the narrower the range of the valence n, the smaller the number of multivalent ion peak combination candidates that satisfy the above formula (1) (in other words, Fake candidates that do not meet the criteria are excluded).

  If only the polyvalent ion peak derived from the target compound appears in the mass spectrum, only one combination candidate is extracted in step S5, which is a combination of true multivalent ion peaks derived from the target compound. However, in general, peaks derived from various noises, peaks derived from other compounds or impurities that could not be sufficiently separated by LC10, and the like appear on the mass spectrum. Therefore, when such a peak appears in a mass-to-charge ratio that satisfies the formula (1) with respect to another molecular weight that is not the true molecular weight of the target compound, a plurality of combination candidates including one or more false combinations in step S5. Will be extracted.

  Then, next, the multivalent ion data analysis processing unit 42 includes one peak (intensity upper peak) having a higher signal intensity in the mass spectrum in order to exclude a combination candidate including only a peak having a particularly low signal intensity. A combination candidate that does not exist is excluded (step S6). Specifically, the signal intensity of the peak (base peak) having the maximum signal intensity among the peaks appearing in the mass spectrum is obtained, and the intensity threshold value is obtained by multiplying the signal intensity by the relative intensity threshold value set in step S1. Ask. Therefore, this intensity threshold varies with the signal intensity of the base peak. Then, a peak whose signal intensity is greater than or equal to the intensity threshold value is extracted from the peaks appearing in the mass spectrum, and the peak may be used as an upper intensity peak. In this case, the number of intensity upper peaks is indefinite, but if there are too many peaks showing an intensity equal to or greater than the intensity threshold, a predetermined number of peaks may be selected in descending order of signal intensity. Further, without performing peak selection based on the intensity threshold, a predetermined number of peaks may be selected in descending order of signal intensity among all peaks appearing in the mass spectrum, and may be used as the higher intensity peak.

  Then, for each combination candidate remaining in the selection in step S6, the molecular weight (neutral mass) of the target compound is calculated based on the mass-to-charge ratio of the multivalent ion peak (candidate) (step S7), and the combination The candidates are listed, and the created list is displayed on the screen of the display unit 53 via the central control unit 51 (step S8). In the example shown in FIG. 4, a combination candidate list display field 101 is provided at the bottom of the display screen 100, and as shown in FIG. 5, the molecular weight obtained from each combination candidate and the number of contained polyvalent ion peaks ( The number of peaks is displayed in a list format. A display field 102 for displaying a mass spectrum at the holding time T is provided at the upper left portion of the display screen 100. In FIG. 5, the centroided mass spectrum is displayed in the display field 102, but it is also possible to display the profile data and the centroided mass spectrum in an overlapping manner.

  The user looks at the combination candidate list displayed on the display screen 100 of the display unit 53 as described above, and designates, for example, one combination candidate using the input unit 52 (step S9). The combination candidates designated as shown in FIG. 5 are displayed in reverse video. In response to the above designation, the multivalent ion data analysis processing unit 42 acquires information such as the mass-to-charge ratio and valence of the multivalent ion peak candidate included in the designated combination candidate, and creates a multivalent ion peak list. The created list is displayed in the multivalent ion peak list display field 103 at the center of the right side of the display screen 100 displayed on the display unit 53 via the central control unit 51 (step S10). In addition, a neutral mass spectrum is obtained by deconvolution of the mass spectrum of the multivalent ions listed in the multivalent ion peak list, and this is displayed in the neutral mass spectrum display column 104 in the upper right part of the display screen 100 ( Step S11).

  Furthermore, data in a predetermined time range near the retention time T with respect to the mass-to-charge ratio of the multivalent ion peak listed in the multivalent ion peak list is acquired from the data collection unit 41, and a mass chromatogram is created for each multivalent ion. Then, they are superimposed and displayed on the mass chromatogram display column 105 in the left center portion of the display screen 100 (step S12). In the display example of FIG. 5, only two multivalent ions are included in the designated combination candidate, so two types of mass chromatograms are drawn in the mass chromatogram display column 105. That is, when one combination candidate is designated from the combination candidate list in step S9, the multivalent ion peak list, neutral mass spectrum, and mass chromatogram corresponding to the designated combination candidate are displayed on the same display screen 100. Is displayed. Displaying a mass chromatogram of a plurality of multiply charged ions included in a combination candidate has the following meaning.

  The example of FIG. 3A is a case where the mass-to-charge ratio of the multivalent ions included in the combination candidates is M1 and M2, and the example of FIG. 3B is the mass-to-charge ratio of the multivalent ions included in the combination candidates. Is M3, M4. When the combination candidate shown in FIG. 3A is designated, a mass chromatogram near the retention time T = T1 at the mass to charge ratios M1 and M2 is created and displayed. The multivalent ions of different valences derived from the same compound have different signal intensities themselves, but in any of the mass chromatograms, a peak top appears at the retention time T1, and the peaks should have a similar shape. FIG. 3A shows such an example. A peak top appears at the retention time T1 in the two mass chromatograms, and the peak shapes are similar. If it can be confirmed that the mass chromatogram is in this state, it can be estimated with high accuracy that these multivalent ions are derived from the same target compound.

  On the other hand, when the multivalent ion peak candidate included in the combination candidate is not actually derived from the target compound or is due to noise, no peak top appears in the retention time T1 in the mass chromatogram, or the peak shape May be different. FIG. 3B shows such an example. In one of the two mass chromatograms at the mass to charge ratios M3 and M4, a peak having a peak top does not appear at the retention time T1, and the peak shape is also clear. Is different. If it can be confirmed that the mass chromatogram is in such a state, it can be estimated with high accuracy that the multivalent ion peak candidate is a false peak not derived from the target compound.

  When a plurality of combination candidates are listed in the combination candidate list, the user designates combination candidates one by one using the input unit 52. As the designation is changed, the multivalent ion peak list, neutral mass spectrum, and mass chromatogram displayed on the display screen 100 are updated. The user confirms the shape and peak position of the mass chromatogram drawn in the mass chromatogram display field 105. Then, from the result, the most appropriate combination is recognized as a polyvalent ion peak derived from the target compound, and a precise molecular weight and neutral mass spectrum of the target compound are obtained (step S13).

  As described above, according to the LC / MS of this example, even when the number of multivalent ions generated from the compound is small, specifically about 2 to 3 types, noise and impurities are present. By eliminating the influence of another compound that is not sufficiently separated by LC, a polyvalent ion derived from the target compound can be found, and a highly accurate molecular weight and neutral mass spectrum can be obtained.

  In the above embodiment, the user himself / herself performs the operation of selecting a combination candidate from the combination candidate list and the task of recognizing the position and peak shape of the peak top of the mass chromatogram. It may be performed automatically and finally the most appropriate combination candidate may be extracted and presented to the user. Specifically, when the peak top exists within a predetermined allowable error range with respect to the retention time T1 of the target compound, it can be determined that the peak top position is acceptable. For example, in order to determine the similarity of peaks in multiple mass chromatograms, the peak top height is standardized, the error at each time of both peaks is calculated, and the similarity is calculated from the sum of these errors. It is good to calculate the index value to judge.

  It should be noted that the above embodiment is merely an example of the present invention, and it is obvious that modifications, corrections, and additions that are appropriately made within the scope of the present invention are included in the scope of the claims of the present application.

10 ... Liquid chromatograph (LC)
DESCRIPTION OF SYMBOLS 11 ... Mobile phase container 12 ... Liquid feed pump 13 ... Injector 14 ... Column 20 ... Mass spectrometry part (MS)
21 ... Ionization chambers 22, 23 ... Intermediate vacuum chamber 24 ... Analysis chamber 25 ... ESI nozzle 26 ... Desolvation tubes 27, 29 ... Ion guide 28 ... Skimmer 30 ... Quadrupole mass filter 31 ... Detector 40 ... Data processing unit 41 Data collection unit 42 Multivalent ion data analysis processing unit 50 Analysis control unit 51 Central control unit 52 Input unit 53 Display unit 100 Display screen 101 Combination candidate list display column 102 Observation mass spectrum display column 103 ... multivalent ion peak list display field 104 ... neutral mass spectrum display field 105 ... mass chromatogram display field

Claims (3)

In a data processing apparatus for a chromatograph mass spectrometer that analyzes data on multivalent ions derived from a target compound collected by a chromatograph mass spectrometer,
on the mass spectrum obtained in the vicinity of the retention time of a) the subject compound by extracting a plurality of candidate multivalent ion peaks having different valences for the same molecular weight is estimated to be derived from the same compound, the target compound Multivalent ion candidate extraction means for obtaining a plurality of candidate combinations of derived multivalent ion peaks,
b) For each of a plurality of multivalent ion peak candidates included in each of a plurality of combination candidates obtained by the multivalent ion candidate extraction means, create a mass chromatogram at least in the time range near the retention time of the target compound Means for creating a mass chromatogram;
c) In order to select highly reliable combination candidates from the plurality of combination candidates obtained by the multivalent ion candidate extraction means, each of the plurality of combination candidates is created by the mass chromatogram creation means. Further, a display means for displaying a plurality of mass chromatograms for a plurality of multivalent ion peak candidates included in one combination candidate on the same screen,
A data processing apparatus for a chromatograph mass spectrometer, comprising:
In a data processing apparatus for a chromatograph mass spectrometer that analyzes data on multivalent ions derived from a target compound collected by a chromatograph mass spectrometer,
a) On the mass spectrum obtained near the retention time of the target compound, by extracting candidates for multiple multivalent ion peaks with different valences for the same molecular weight estimated to be derived from the same compound, A multivalent ion candidate extracting means for obtaining a plurality of multivalent ion peak combination candidates;
b) For each of a plurality of multivalent ion peak candidates included in each of a plurality of combination candidates obtained by the multivalent ion candidate extraction means, create a mass chromatogram at least in the time range near the retention time of the target compound Means for creating a mass chromatogram;
c) For each of a plurality of combination candidates obtained by the multivalent ion candidate extraction means, a plurality of masses for a plurality of multivalent ion peak candidates included in one combination candidate created by the mass chromatogram creation means. based on the chromatogram, that they multivalent ion peaks candidate determining whether a multivalent ion peaks originating from the target compound, a candidate determination means for selecting a reliable combination candidates,
A data processing apparatus for a chromatograph mass spectrometer, comprising:
A data processing apparatus for a chromatograph mass spectrometer according to claim 1 or 2,
The multivalent ion candidate extraction means selects combination candidates on the condition that at least one peak having a relatively high signal intensity is included in the mass spectrum obtained near the retention time of the target compound. A data processing apparatus for a chromatograph mass spectrometer.

Images