JP5150370B2 - Mass spectrometry system and mass spectrometry method - Google Patents

Description

  The present invention relates to a mass spectrometry system and a mass spectrometry method, and relates to a technique for performing identification using a spectrum obtained by mass spectrometry.

  In a general mass spectrometry method, a target sample is ionized and the ions are sent to a mass spectrometer. In the mass spectrometer, the ion intensity is measured for each mass-to-charge ratio (m / z) comprising the ratio of mass (m) to valence (z) with respect to the transmitted ions. As a result, a mass spectrum in which the horizontal axis is m / z and the vertical axis is ionic strength can be obtained.

  Each component contained in the sample appears as a peak of ionic strength on the mass spectrum as a result of being measured by the mass spectrometer. When a sample contains a plurality of components, a plurality of peaks appear on the mass spectrum. The process of obtaining the centroid point at these peaks is called centroiding, and this centroid point is generally used as the mass number of the sample component corresponding to the peak.

As the mass spectrometry method, there are an MS analysis method in which a sample is ionized and measured as it is, and a tandem mass spectrometry method in which a specific ion is selectively dissociated and then generated ions are measured after the sample is ionized and measured. In tandem mass spectrometry, ions that are the targets of dissociation are called parent ions. Tandem mass spectrometry has a function of performing dissociation and mass analysis in multiple stages, such as mass analysis of ions generated by further selecting and dissociating a parent ion from dissociated ions. Hereinafter, the n-th stage mass spectrometry is referred to as MS ⁿ . Tandem mass spectrometry is carried out for the purpose of acquiring sample structure information in addition to sample mass number information. By comparing the result of tandem mass spectrometry with the database, it becomes possible to identify the components contained in the sample.

  A system that combines a chromatograph and a mass spectrometer is often used for a sample containing a large amount of various components such as a biological sample such as protein or sugar. In the chromatograph, the components in the sample are separated in time due to the difference in the degree of adsorption of substances on the column, etc., so that it is possible to separate ion species that are difficult to separate with a mass spectrometer.

  In mass spectrometry using a chromatograph, mass spectrometry and tandem mass spectrometry are repeatedly performed in a mass spectrometer from the start of sample separation in the chromatograph until all the samples flow out of the chromatograph. When the sample to be analyzed is known, it is possible to directly specify the mass number of the ion to be subjected to tandem mass spectrometry. However, if the target is an unknown sample, it is essential to perform mass analysis once and select ions for tandem mass analysis, and a method of repeating mass analysis and tandem mass analysis as one session is used.

Regarding techniques of mass spectrometry and tandem mass spectrometry for the purpose of identifying an unknown sample, for example, Patent Document 1 and Patent Document 2 can be cited.
(1) Patent Document 1 describes a technique for selecting ions that preferentially perform tandem mass spectrometry and ions that do not require tandem mass spectrometry by using a database.
(2) In Patent Document 2, an internal database is searched after obtaining a mass spectrum obtained by mass analysis, and parent ions are classified into several groups according to the number of parent ion candidates and the like, and tandem mass spectrometry is performed for each group. The method is described.

JP 2004-71420 A JP 2007-46966 A

  For the purpose of identifying the components contained in an unknown sample, it is possible to obtain structural information about many components during a single measurement, that is, from the start to the end of the sample flow through the chromatograph. It is desirable to increase the accuracy of identification. Therefore, a technique for selectively performing tandem mass spectrometry on component ions that are meaningful in identification, such as Patent Document 1, and a high-efficiency tandem mass analysis for many component ions, such as Patent Document 2. Techniques to implement have been devised.

  In order to acquire a lot of structural information for components contained in a sample, increasing the number of tandem mass spectrometry that can obtain structural information during measurement is a major factor. However, conventionally, in order to perform tandem mass spectrometry on an unknown sample, it is necessary to perform mass analysis in advance and select ions for tandem mass spectrometry. The measurement of a sample using a chromatograph usually requires several hours, and during that time, thousands of mass analysis and tandem mass analysis are performed, and the time required for mass analysis of the entire measurement is large. That is, the necessity of performing mass spectrometry in advance for performing tandem mass spectrometry is a problem in increasing the number of tandem mass spectrometry in measurement.

  An object of the present invention is to provide a mass spectrometry system in which the number of tandem mass analyzes in one measurement is increased.

  In the present invention, in the mass spectrometry system composed of the sample separation means and the mass spectrometer, by predicting the intensity change of each peak appearing from the mass spectrum of the mass spectrometry already obtained, One feature is determining the number of tandem mass analyses.

  According to the present invention, by increasing the number of tandem mass analyzes during one measurement, it is possible to acquire a lot of structural information of components in a sample, and the accuracy of identification is improved.

  Examples of the present invention are shown below.

  FIG. 1 shows a mass spectrometry system to which the first embodiment of the present invention is applied. The system in FIG. 1 is a system for identifying components contained in a sample by performing mass spectrometry on an unknown sample, and includes an input unit 1, a display unit 2, a data processing unit 3, and a control. 4, a sample separation unit 5, an ionization unit 6, a mass analysis unit 7, an ion detection unit 8, and a database 9.

  In FIG. 1, first, an unknown sample to be analyzed is introduced into the sample separation unit 5. The sample separation unit 5 temporally separates components in the unknown sample. It is desirable to apply a liquid chromatograph (LC), a gas chromatograph (LC) or the like as an apparatus for performing sample separation.

  The sample that has been separated is ionized in the ionization section 6. Ionization methods include electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI), electron ionization (EI), and chemical ionization (CI), depending on the sample to be analyzed and the purpose of the analysis. An ionization method is selected.

The components in the ionized sample are separated by the mass analyzer 7 according to the ion mass-to-charge ratio (m / z). Here, m is the ion mass, and z is the charge valence of the ion. Various mass spectrometers can be applied to the mass analyzer, but a mass spectrometer capable of tandem mass analysis, such as a quadrupole mass spectrometer and an ion trap mass spectrometer, is desirable. In addition to the method (MS) in which a sample is ionized and analyzed as it is, the mass spectrometric method includes a tandem that selects a specific sample ion (parent ion) by mass and dissociates it to generate dissociated ions. There is mass spectrometry (MS ² ). In tandem mass spectrometry, dissociation and mass analysis may be performed in multiple stages (MS ⁿ ), such as dissociation and mass analysis by further selecting a parent ion from the dissociated ions. The molecular structure information of the parent ion is acquired by performing tandem mass spectrometry, and the unknown sample is identified using this information.

  Examples of parent ion dissociation methods include a collision induced dissociation method and an electron capture dissociation method. The collision dissociation method is a method in which a buffer gas such as helium collides with ions to dissociate, and the electron capture / dissociation method dissociates by irradiating low energy electrons and capturing a large amount of low energy electrons in the parent ion. Is the method.

  The ions separated in the mass analysis unit 7 are detected by the ion detection unit 8, and processing and analysis of the data detected by the data processing unit 3 are performed. The analyzed result is displayed on the display unit 2 as a mass spectrum. A series of analysis processes of separating the sample, detecting it as ions, and displaying it as a mass spectrum is controlled by the control unit 4. Further, the input unit 1 is provided as an interface for the user to control the analysis process and the apparatus.

  The data processing unit 3 performs post-processing such as noise removal, peak determination, and isotope peak removal on the acquired mass spectrum. By comparing the mass spectrum obtained in this way with the information in the database 9, components contained in the sample are identified.

  A database 9 used for sample identification is a database in which mass spectra of known samples are stored. A database published on the Internet is used.

FIG. 2 shows a general processing flow for identifying a component in an unknown sample by tandem mass spectrometry. The processing flow of FIG. 2 includes a sample introduction 10, a sample separation 11, an ionization 12, a mass analysis (MS) 13, a dissociation 14 of a parent ion, and a mass analysis (MS ² ) 15. First, sample introduction 10 is performed on an unknown sample to be identified, and sample separation 11 is performed. The components in the sample are separated by time by a chromatograph such as LC or GC, and flow out of the chromatograph every time. The components sent from the chromatograph are sequentially ionized 12. Thereafter, a series of processes of mass analysis (MS) 13, parent ion dissociation 14, and mass analysis (MS ² ) 15 are repeatedly performed on the sample components that are ionized and sent. First, by performing mass spectrometry (MS) 13, the components contained in the sample are analyzed, and the parent ion is selected. For the selection of the parent ion, a method of selecting one having a high ionic strength is generally used. In addition, there are cases where methods such as selective exclusion of ions once dissociated are used. Next, ions selected as parent ions are dissociated, and ions generated by the dissociation are subjected to mass spectrometry (MS ² ) 15. The mass spectrum (MS ² spectrum) obtained by mass spectrometry (MS ² ) 15 has the molecular structure information of the parent ion, and is used for identification of each component contained in the sample. By repeatedly performing the processes of mass spectrometry (MS) 13, dissociation of parent ions 14, and mass analysis (MS ² ) 15, MS ² spectra are acquired for various components in the unknown sample and accumulated as sample information. . In general, the time required for the mass analysis (MS) 13 and the time required for performing the mass analysis (MS ² ) 15 by performing the dissociation 14 of the parent ion are about 0.5 to 2.0 seconds, respectively. On the other hand, in the case of analyzing the sample, the time until the sample finishes flowing out of the chromatogram depends on the apparatus conditions in the sample separation unit 5 of LC or GC, but generally the time required is about several hours, In many cases, a series of processes from mass spectrometry (MS) 13 to mass spectrometry (MS ² ) 15 is repeated thousands of times while the sample has finished flowing out of the chromatogram. By collating the MS ² spectrum acquired in this way with the database 9, the components contained in the unknown sample are identified.

In FIG. 3, the schematic of the mass spectrometry flow in the 1st Example of this invention is shown. The processing flow of the first embodiment of the present invention mainly includes sample introduction 10, sample separation 11, ionization 12, mass analysis (MS) 13, determination of MS ² times 16, dissociation of parent ions 14, and mass analysis. (MS ² ) 15 and a predetermined number of times end determination 17. The main feature of the first embodiment of the present invention is that it comprises the process of determining 16 times of MS ² after performing mass spectrometry (MS) 13. Details of the processing flow according to the first embodiment of the present invention will be described below.

First, sample introduction 10 is performed on an unknown sample to be identified, and sample separation 11 is performed. Ionization is performed on the components in the sample separated by the chromatogram, and mass spectrometry (MS) 13 is performed. Here, in the present invention, from the mass spectrum obtained by mass spectrometry (MS) 13, the number of parent ion dissociation 14 and mass analysis (MS ² ) 15 to be performed later, and the dissociation at that time are performed. Determine the parent ion. Hereinafter, a series of processes of dissociation 14 of parent ions and mass spectrometry (MS ² ) 15 will be referred to as MS ² analysis. The MS ² analysis is performed for the number of times determined in this process, and when the predetermined number of times is completed, the process of the mass spectrometry (MS) 13 is performed again. This process is repeated while the sample flows out of the chromatogram, and the MS ² spectrum is accumulated. In this way, by determining the number of MS ² analyzes to be performed by the determination 16 of the number of MS ² after the mass analysis (MS) 13, a plurality of times of MS ² analysis is performed for one mass analysis (MS) 13. Will be implemented. Thereby, compared with the conventional process flow, the mass analysis (MS) 13 performed while a sample flows out from a chromatograph decreases, and the number of times of MS ² analysis increases. As a result, more MS ² spectra can be acquired than in the conventional processing flow, which leads to an improvement in accuracy and an increase in the number of components to be identified when identification is performed using the database 9. In the MS ² times determination 16, the optimum number of times to perform the MS ² analysis is determined.

FIG. 4 shows a schematic diagram of the flow of determining the MS ² times in the first embodiment of the present invention. The MS ² frequency determination 16 includes a peak extraction process 18, a peak intensity change calculation 19, an MS ² frequency determination 20, and a peak information database 21. In the peak extraction process 18, a peak determination process is performed on a mass spectrum obtained by performing mass spectrometry (MS). In peak determination, it is desirable to perform noise removal such as smoothing as preprocessing. After peak determination, only the main isotope peak is extracted except for the isotope peak. As a result, a peak list consisting of m / z, ionic strength, and retention time is generated.

  FIG. 5 is an explanatory diagram of the peak list in the first embodiment of the present invention. The peak list includes a peak list m / z indicated by reference numeral 23, a peak list ion intensity indicated by reference numeral 24, and a peak list holding time indicated by reference numeral 25 (minutes) corresponding to the peak list peak No. indicated by reference numeral 22, respectively. ) Is displayed. The peak list retention time (minutes) 25 is the time from the start time of the sample separation 11 to the time when the mass analysis (MS) 13 is performed, and is equal in the peaks obtained by the same mass analysis (MS) 13. Become. The contents of the peak list are registered in the peak information database 21 as peak information. The peak information database 21 stores peak information obtained when mass spectrometry (MS) is performed in the past.

  In the next peak intensity change calculation 19 of the peak extraction process 18, by using the past peak information stored in the peak information database 21 for each peak obtained as a peak list, the subsequent change in ion intensity is performed. Is estimated. The method for estimating the ionic strength change for one peak existing on the peak list is as follows.

  First, referring to the peak information database 21, a target peak is searched from a peak list obtained as a result of past mass spectrometry (MS) 13. In the search, a peak with a matching m / z is searched. Since m / z does not match at all for ions of the same component due to noise, conditions, or the like, peaks matching at a certain tolerance Δm / z are extracted as the same peak. Here, Δm / z is desirably a preset value or a value that can be arbitrarily set by the user.

  FIG. 6 shows an example of peaks obtained as a result of the search. The search result includes a search result peak No. indicated by reference numeral 26, a search result m / z indicated by reference numeral 27, a search result ion intensity indicated by reference numeral 28, and a search result holding time (minute) indicated by reference numeral 29. It is. FIG. 6 shows an example in which three peaks (peaks No. 1, 2, 3) are found as a result.

  Next, a change in the ion intensity of the target peak is predicted from the search result ion intensity 28 and the search result holding time (minute) 29 in the search result. The peak obtained by searching the retention time on the horizontal axis and the ionic strength on the vertical axis is plotted on the coordinate axis.

  FIG. 7 shows a plot of the results of FIG. 6 as an example. That is, FIG. 7 is an explanatory diagram of the ionic strength retention time in the first embodiment of the present invention. The peak P1 (reference numeral 30), the peak P2 (reference numeral 31), and the peak P3 (reference numeral 32) coincide with the peak No. (reference numeral 26) in FIG. Based on the relationship between the search result holding time (minutes) 29 and the search result ion intensity 28 in FIG. 6, how the ion intensity changes with respect to the future holding time is predicted.

  Usually, components contained in a sample are subjected to sample separation and subjected to mass spectrometry. As a result, the ionic strength changes in a shape similar to a Gaussian function curve with respect to the retention time. Therefore, a future change in ion intensity is predicted by fitting the relationship between the ion intensity and the retention time obtained so far with a Gaussian function.

  FIG. 8 shows the results when fitting is applied to the relationship between the ion intensity and the retention time in FIG. A Gaussian function having an optimal shape is applied so that the error is reduced at each point of the peak P1 (reference numeral 33), the peak P2 (reference numeral 34), and the peak P3 (reference numeral 35). This Gaussian function curve 36 is considered as a future change in ionic strength.

  A method for obtaining a Gaussian function curve from the already obtained ionic strength and retention time is shown below. First, the Gaussian function curve is expressed by the following equation, where I is the ionic strength and t is the retention time.

  Here, a, b, and c are parameters for determining the shape of the Gaussian function curve. These parameters are determined from the already acquired ionic strength and retention time. When making a decision, the natural logarithm of both sides of the above equation is converted as follows.

  This equation is regarded as a polynomial for t and is transformed as follows.

  Here, variables A, B, and C are newly defined as follows.

  The above equation becomes the following two-dimensional polynomial when variables A, B, and C are used.

  The values of A, B, and C are determined by applying the least square method to the two-dimensional polynomial, using the already obtained ion intensity I and holding time t. When the values of A, B, and C are obtained, a, b, and c are determined by the following equations from (Equation 4), (Equation 5), and (Equation 6) using the respective values.

  FIG. 9 is an explanatory diagram of a representative example of peak search results in the first embodiment of the present invention. In this embodiment, an example in which the ion intensity and retention time of a certain peak is shown in FIG. 9 as a result of searching the peak information database.

  First, a natural logarithm is taken with respect to the ion intensity 39 for each peak. The result is shown as logarithmic ionic strength 41 in FIG. Next, the values of A, B, and C are determined by performing the least square method using a set of four logarithmic ionic strengths and holding times. As a result, A = −1.15, B = 6.83, and C = −6.76. By substituting these into (Expression 8), (Expression 9), and (Expression 10), it is determined that a = 28.89, b = 2.96, and c = 0.657.

  FIG. 11 shows a diagram in which a Gaussian function curve is drawn using these parameters. The actual point 42 is obtained data of ion intensity and holding time, and the dotted line is an actual calculation Gaussian function curve 43 determined by the above means, and indicates prediction of change in ion intensity.

Subsequently, the future existence time of the target peak is obtained from the change in ionic strength obtained by the above means. FIG. 12 is an explanatory diagram of the existence time in the first embodiment of the present invention. As shown in FIG. 12, in obtaining the existence time, a certain threshold value 44 is applied to the ion intensity change, and if the ion intensity is equal to or greater than the threshold value 44, it is assumed that an ion exists and the ion intensity from the current time. The time until the value becomes smaller than the threshold 44 is defined as the existence time of the target peak. FIG. 12 shows the existence time 45 obtained with respect to FIG. As a setting method of the threshold value 44, there are a fixed value or a method that the user designates from the input unit. In addition, the ion intensity is directly specified as a method for specifying the threshold 44. Moreover, the method of designating by the relative value (%) with respect to the maximum ion intensity may be used, and it is desirable that the minimum intensity required for performing mass spectrometry (MS ² ) is set.

Next, the number of MS ² analyzes (MS ² times) that can be performed during the existence time 45 is determined for the target peak. The quotient obtained by dividing the existence time by the time required for dissociation of the parent ion and mass spectrometry (MS ² ) is defined as the number of times.

As described above, the process from the peak searching process in the peak information database 21 until the MS ² count is obtained is performed for the peak obtained by the current mass spectrometry (MS). In selecting a target peak, it is also possible to narrow down the peak by setting a certain threshold value.

As a result of the above, an MS ² times list in which MS ² times are obtained for each peak obtained by mass spectrometry (MS) is generated. FIG. 13 shows an example of the MS ² times list. Based on this MS ² times list, the number of MS ² analyzes to be performed and the parent ions are determined. The number of times of execution of MS ² analysis, using the maximum of the MS ² times at the peak of the MS ² times list. However, in order to cope with a case where the number of times of MS ² becomes large, the user can set the maximum number in advance. With the above processing, the number of MS ² analyzes to be performed next is determined from the results obtained by mass spectrometry (MS).

In FIG. 3, after determining 16 times of MS ² , the determined number of parent ion dissociations 14 and mass spectrometry (MS ² ) 15 are performed. When the sample separation 11 is performed, the parent ion dissociation 14 and the mass analysis (MS ² ) 15 are repeated, the mass analysis (MS) 13 is performed when the predetermined number of times is reached, and the MS ² times determination 16 is performed again. Repeat as long as you are.

In selecting the parent ion in the parent ion dissociation 14 and mass spectrometry (MS ²⁾ 15, make a selection from the peak of the MS ² in the number list obtained by the determination of the MS ² times. In selecting a peak, a peak in which the current number of repetitions of parent ion dissociation and mass spectrometry (MS ² ) and the MS ² times list MS ² times 50 coincide is selected.

The peak selection method will be described using the MS ² times list in FIG. First, the largest MS ² times Listing MS ² times 50 in MS ² times List "5" is the number of times of execution of the parent ion dissociation 14 and mass spectrometry (MS ²⁾ 15. First, the first parent ion dissociation 14 and mass spectrometry (MS ²⁾ 15, MS ² times MS ² times Listing MS ² times 50 list makes a selection from among the peaks of "1". Here, the MS ² times list peak No. 46 corresponds to the peaks of “2” and “4”. When there are a plurality of peaks as described above, there are a method for selecting one having a high ionic strength and a method for selecting one having a larger mass number. In this embodiment, when there are a plurality of peaks, a peak having a high ionic strength is selected. Therefore, in this example, the peak having the MS ² times list peak No. 46 of “4” is set as the parent ion of the first parent ion dissociation 14 and mass analysis (MS ² ) 15. Next, in the second parent ion dissociation 14 and the parent ion of mass spectrometry (MS ² ) 15, the MS ² frequency list MS ² frequency 50 is selected from the peaks of “2”. Again, the MS ² times list peak No. 46 corresponds to the two peaks “1” and “7”, but the MS ² times list peak No. 46 having a large ionic strength is the second peak. Select as parent ion in parent ion dissociation 14 and mass spectrometry (MS ² ) 15. Next, for the parent ion dissociation 14 and mass spectrometry (MS ² ) 15 for the third time, there is no peak with the MS ² frequency of 3 in the MS ² frequency list. In such a case, the target MS ² times list MS ² times 50 is incremented by 1, and the parent ion is selected from the peaks in which the MS ² times list MS ² times 50 is “4”. Here, the MS ² times list peak No. 46 corresponds to the peaks of “3” and “6”, and the peak of MS ² times list peak No. 46 having a high ionic strength is selected as the parent ion. .

Here, MS ² when the peak of the number list MS ² times 50 is "4" is also such as not to exist, further increases 1 MS ² times Listing MS ² times 50, MS ² times Listing MS ² times 50 ' The MS ² times list MS ² times 50 is increased until a peak is found, such as searching from the peaks of “5”. MS ² times list When the number of MS ² times 50 is increased to reach the number of times of execution, the processes of the parent ion dissociation 14 and the mass analysis (MS ² ) 15 are finished, and the mass analysis (MS) 13 is performed again. Next, in the fourth parent ion dissociation 14 and mass spectrometry (MS ² ) 15, the MS ² frequency list MS ² frequency 50 is similarly selected from the peaks of “4”. MS peaks of ² number list MS ² times 50 is "4" is MS ² times list peak No.46 corresponds the peak of "6" and "3", MS ² times list peak No.46 is "6 ”Is excluded because it is already selected at the third time. Although it is possible to select a peak with MS ² times list peak No. 46 of “6” by repeating the setting according to the setting, by excluding it in this embodiment, the parent ion can be applied to as many species as possible. Dissociation 14 and mass spectrometry (MS ² ) 15 are performed. Finally, in the fifth parent ion dissociation 14 and mass spectrometry (MS ² ) 15, the MS ² times list peak No. 46 in which the MS ² times list MS ² times 50 is “5” is selected as the peak. . By the above method, the parent ions in the first to fifth parent ion dissociation 14 and mass spectrometry (MS ² ) 15 have peaks No. of “4”, “7”, “6”, “3”, The peak “5” is selected in order.

As described above, by repeating the process of performing mass spectrometry (MS) 13 and determining 16 times of MS ² and performing the determined number of times of dissociation 14 of parent ions and mass analysis (MS ² ) 15, Multiple mass analysis (MS ² ) 15 can be performed on the mass analysis (MS) 13, and more MS ² spectra can be obtained compared to the conventional method.

  Next, FIG. 15 shows an example of a UI (user interface) in the present embodiment. In the intensity prediction condition 52, conditions related to the prediction of ion intensity are set. In the present embodiment, as setting items, a matching margin (m / z) setting field 53 and a threshold value are provided. The coincidence tolerance (m / z) setting field 53 is used for searching for a peak from the peak information database, and in this embodiment, designation is made by the mass number (m / z). In addition to the direct designation by the mass number (m / z), a method of designating by the percentage (%) of the mass number of the peak is also conceivable. The threshold setting column 54 is a value used when obtaining the existence time in the Gaussian function curve. In this embodiment, the direct ion intensity is designated. In addition, a method of designating a percentage (%) with respect to the maximum ionic strength of the obtained Gaussian function curve is also conceivable.

The MS ² execution condition 55 sets conditions regarding the execution of the MS ² analysis. In the present embodiment, a maximum number setting field 56 and a priority condition are provided. The maximum number of times limits the number of times the parent ion dissociation 14 and mass spectrometry (MS ² ) 15 are performed. Since the number of times of MS ² execution is automatically determined, it is used when the user wants to limit the number of times in advance. The priority condition setting unit 57 is used when a plurality of peaks are candidates for implementation. In this embodiment, it consists of two options of mass number and strength. When the mass number is selected, the peak with the larger mass number is selected as the parent ion. When the intensity is selected, the peak having the higher intensity is selected as the parent ion.

BRIEF DESCRIPTION OF THE DRAWINGS The conceptual diagram of the whole mass spectrometry system in the 1st Example of this invention. Schematic of the conventional mass spectrometry flow. The schematic of the mass spectrometry flow in the 1st example of the present invention. The schematic of the flow of MS ² times determination in the 1st example of the present invention. Explanatory drawing of the peak list | wrist in the 1st Example of this invention. Explanatory drawing of the peak search result in the 1st Example of this invention. Explanatory drawing of the retention time of the ionic strength in the 1st Example of this invention. Explanatory drawing of the Gaussian function curve in the 1st Example of this invention. Explanatory drawing of the typical example of the peak search result in the 1st Example of this invention. Explanatory drawing of the logarithmic ionic strength in the 1st Example of this invention. Explanatory drawing of the actual calculation result of the Gaussian function curve in the 1st Example of this invention. Explanatory drawing of the presence time in the 1st Example of this invention. Explanatory drawing of MS ² times list | wrist in the 1st Example of this invention. Explanatory drawing of the typical example of MS ² times list | wrist in 1st Example of this invention. FIG. 3 is a schematic diagram of a UI for inputting in the first embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Input part 2 Display part 3 Data processing part 4 Control part 5 Sample separation part 6 Ionization part 7 Mass analysis part 8 Ion detection part 9 Database 10 Sample introduction 11 Sample separation 12 Ionization 13 Mass spectrometry (MS)
14 Dissociation of parent ion 15 Mass spectrometry (MS ² )
16 MS ² times determination 17 Predetermined number end determination 18 Peak extraction process 19 Peak intensity change calculation 20 MS ² times determination 21 Peak information database 22 Peak list peak No.
23 Peak list m / z
24 Peak list ionic strength 25 Peak list retention time (min)
26 Search result peak No.
27 Search result m / z
28 Search result ionic strength 29 Search result retention time (minutes)
30,33 Peak P1
31, 34 Peak P2
32,35 Peak P3
36 Gaussian function curve 37 Peak No. in typical example of search results.
38 m / z in representative examples of search results
39 Ion intensity in a representative example of search results 40 Retention time (minutes) in a representative example of search results
41 Logarithmic ionic strength 42 in a representative example of the search result 42 Actual acquired value 43 Actual calculation Gaussian function curve 44 Threshold value 45 Time 46 MS ² times list peak No.
47 MS ² times list m / z
48 MS ² times list ionic strength 49 MS ² times list holding time (min)
50 MS ² times list MS ² times 51 MS ² analysis condition setting screen 52 Strength prediction condition setting field 53 Matching margin (m / z) setting field 54 Threshold setting field 55 MS ² execution condition setting field 56 Maximum number of times Setting field 57 Priority condition setting section

Claims (2)

In a mass spectrometry system comprising a sample separation section for separating a sample, a mass analysis section provided with the sample separation section, and an input section for setting conditions relating to the mass analysis section,
A mass spectrometry system, wherein the following (a) to (f) are performed during measurement of the first mass spectrometry after sample introduction.
(a) By the time when the predetermined parent ion peak is obtained in the first mass analysis , a parent ion peak that can be a target of tandem analysis is obtained from the already obtained mass spectrum,
(b) Register the peak information including the obtained parent ion peak retention time, the obtained parent ion peak m / z, and the obtained parent ion peak ion intensity information in the database,
(c) Extracting from the database the peak information of the peak of the parent ion to be dissociated and the peak having m / z of the peak and m / z within a predetermined tolerance range,
(d) Peaks extracted from the database are plotted on a mass chromatogram, and these plots are fitted using a Gaussian function to predict future ionic strength changes of the dissociated parent ions,
(e) In the curve fitted with this Gaussian function, find the time when the ion intensity is above a predetermined threshold,
(f) The maximum number of dissociations during one measurement of the parent ion is determined from this time, the dissociation of the parent ion, and the time required for this analysis. A mass spectrometry method comprising performing the following (a) to (f) during the measurement of the first mass spectrometry after sample introduction.
(a) By the time when the predetermined parent ion peak is obtained in the first mass analysis , a parent ion peak that can be a target of tandem analysis is obtained from the already obtained mass spectrum,
(b) Register the peak information including the obtained parent ion peak retention time, the obtained parent ion peak m / z, and the obtained parent ion peak ion intensity information in the database,
(c) Extracting from the database the peak information of the peak of the parent ion to be dissociated and the peak having m / z of the peak and m / z within a predetermined tolerance range,
(d) Peaks extracted from the database are plotted on a mass chromatogram, and these plots are fitted using a Gaussian function to predict future ionic strength changes of the dissociated parent ions,
(e) In the curve fitted with this Gaussian function, find the time when the ion intensity is above a predetermined threshold,
(f) The maximum number of dissociations during one measurement of the parent ion is determined from this time, the dissociation of the parent ion, and the time required for this analysis.

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