WO2023119427A1

WO2023119427A1 - Chromatograph mass spectrometry device

Info

Publication number: WO2023119427A1
Application number: PCT/JP2021/047356
Authority: WO
Inventors: 春菜川満; 和広河村
Original assignee: 株式会社島津製作所
Priority date: 2021-12-21
Filing date: 2021-12-21
Publication date: 2023-06-29

Abstract

A chromatograph mass spectrometry device according to one aspect of the present invention comprises: a measuring unit (1) including a chromatograph unit and a mass spectrometry unit; an ion extracting unit (21) for acquiring a mass spectrum of a compound of interest from a spectrum library (5) in which a standard mass spectrum and compound information including a holding time or a holding indicator are recorded, and for using an intensity of a mass peak observed in the mass spectrum and an m/z value corresponding to the mass peak to extract a monitor ion for each compound of interest; a database creating unit (22) for registering the compound information of the compound of interest and the m/z value of the monitor ion in a database (23); a compound specification accepting unit (24) for accepting a specification, from a user, relating to a target compound to be analyzed, among the compounds registered in the database; a method creating unit (24) for using the registration information in the database to create an analysis method for the target compound; a control unit (26) for controlling an operation of the measuring unit so as to carry out an analysis of a specimen of interest, in accordance with the analysis method; and a compound identifying unit (28) for using an analysis result for the specimen of interest, and the analysis method or the registration information in the database, to identify a compound in the specimen of interest.

Description

Chromatograph mass spectrometer

The present invention relates to a chromatograph mass spectrometer that combines a chromatograph such as a gas chromatograph, liquid chromatograph, or supercritical fluid chromatograph with a mass spectrometer.

In recent years, gas chromatograph-mass spectrometers (GC-MS) and liquid chromatograph-mass spectrometers (LC-MS) have been used in various fields such as residual pesticide testing in food, contaminant testing in environmental water, and metabolomics analysis in biological samples. ) and other chromatographic mass spectrometers are widely used. Hereinafter, GC-MS will be mainly described as an example, but it is clear from the description below that the situation is the same for LC-MS, supercritical fluid chromatograph-mass spectrometer (SFC-MS), and the like.

When identifying an unknown compound in a sample using GC-MS, generally, the measured mass spectrum at the retention time near the peak top of the chromatographic peak detected in the total ion chromatogram (TIC) and the spectral library Compare the pattern with the standard mass spectrum recorded in , and identify the compound by determining that the similarity is greater than or equal to a predetermined threshold or indicates a high value (see Patent Document 1, etc.) . This method is called non-targeted analysis because the compound to be analyzed is not specified in advance. Well-known spectral libraries for GC/MS include the spectral library published by the National Institute of Standards and Technology (NIST) in the United States and the Wiley Registry provided by Wiley in the United States. .

In non-targeted analysis, it is difficult to identify compounds corresponding to minute peaks in TIC when the minute peak is buried in adjacent peaks. Analytical processing such as deconvolution may be used to separate such overlapping peaks. However, since deconvolution extracts a large number of peaks, including peaks derived from noise, a great deal of effort is required to find peaks derived from compounds actually contained in the sample. Moreover, when the number of compounds contained in the sample is large, it is difficult to extract peaks with sufficient accuracy even if deconvolution is applied.

On the other hand, if a compound to be checked for inclusion in a sample, that is, a target compound, is determined, monitor ions (quantitative ions in the case of quantitative analysis), which are representative ions derived from the compound, are used. The mass-to-charge ratio (m/z: strictly speaking, italicized “m/z”, but referred to herein as “m/z” or “mass-to-charge ratio”) value and retention GC/MS analysis is performed using an analysis method prepared in advance based on time (indicator) and the like, and the compound is identified from the analysis results. This technique is called targeted analysis.

In target analysis, peaks can be detected from the extracted ion chromatogram (sometimes called "mass chromatogram" in common usage) at the m/z value of the monitor ion. Therefore, even minute peaks that are buried in adjacent peaks on the TIC can be accurately and efficiently detected to identify the compound (see Non-Patent Document 1, etc.). In particular, a multi-component simultaneous analysis method that searches for many types of compounds (500 to 1000 or more compounds) as target compounds while taking advantage of the high identification accuracy and efficiency of such target analysis is known as wide target analysis. It is In recent years, wide-target analysis has attracted attention as a very powerful technique in metabolomics analysis and the like.

WO2018/138901

In order to perform target analysis using GC-MS, it is necessary to create an analysis method for target analysis prior to analysis. For this purpose, mass spectra obtained by analyzing standard samples containing target compounds and mass spectra obtained from a library containing compound information of target compounds are used to monitor ions for each compound. and the m/z value of the reference ion (also called confirming ion) must be determined by the user. However, when the number of target compounds is enormous as in wide target analysis, such work is quite troublesome and requires a great deal of labor and cost. Also, in general, the ion corresponding to the peak showing the maximum signal intensity in the mass spectrum is often selected as the monitor ion. It often overlaps with the ions of compounds. As a result, compounds may not be identified accurately.

The present invention has been made in view of the above problems, and its object is to reduce the burden of complicated work on the user in target analysis for a large number of compounds, and to analyze a large number of compounds at a high level. An object of the present invention is to provide a chromatographic mass spectrometer capable of identifying with high accuracy.

One aspect of the chromatograph mass spectrometer according to the present invention is
a measurement unit including a chromatograph unit that separates the compounds in the sample in the time direction, and a mass spectrometry unit that detects each separated compound;
A mass spectrum of the target compound is obtained from a standard mass spectrum and a spectrum library containing compound information including retention time or retention index, and the intensity of the mass peak observed in the mass spectrum and the mass corresponding to the mass peak an ion extraction unit for extracting monitor ions for each target compound using the charge ratio value;
a database creating unit for registering in a database compound information of the target compound and mass-to-charge ratio values of monitor ions extracted by the ion extracting unit;
a compound designation reception unit that receives designation by a user of a target compound to be analyzed among the compounds registered in the database;
a method creation unit that creates an analysis method for the target compound using registered information in the database;
a control unit that controls the operation of the measurement unit so as to perform chromatographic mass spectrometry on a target sample according to the analysis method;
A compound identification unit that identifies a compound in the target sample by using the chromatographic mass spectrometry result for the target sample and the analysis method or registered information in the database;
Prepare.

In the above aspect of the present invention, the user himself/herself can perform the analysis of the standard sample containing the target compound, or extract the appropriate monitor ion from the mass spectrum obtained for the target compound. The mass-to-charge ratios of monitor ions suitable for compound identification are automatically extracted and registered in a database for analysis. As a result, according to the chromatograph mass spectrometer of the above aspect of the present invention, a large number of compounds can be analyzed with high accuracy while reducing the burden of complicated work on the user in target analysis for a large number of compounds. can be identified.

1 is a schematic configuration diagram of a GC-MS system that is an embodiment of the present invention; FIG. 4 is a flow chart showing an example of the flow of compound identification in the GC-MS system of the present embodiment. FIG. 3 is a flowchart showing an example of extraction processing of monitor ions and the like in FIG. 2; FIG. FIG. 4 is an explanatory diagram of a procedure for registering a database for target analysis in the GC-MS system of the present embodiment; FIG. 2 is an explanatory diagram of registered contents of a method file in the GC-MS system of the present embodiment; FIG. 4 is a diagram showing an example of the relationship between mass spectra, monitor ions, and reference ions; FIG. 4 is a diagram showing an example of a monitor ion extraction condition setting screen in the GC-MS system of the present embodiment;

[Configuration of GC-MS system as one embodiment]
A GC-MS system that is one embodiment of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic configuration diagram of the GC-MS system of this embodiment.

This GC-MS system comprises a measurement section 1 including a GC section 1A and an MS section 1B, a control/processing section 2, an input section 3, a display section 4, and a spectrum library 5.

The GC unit 1A includes a sample vaporization chamber 10 for vaporizing a small amount of liquid sample, a microsyringe 11 for injecting the liquid sample into the sample vaporization chamber 10, a column 13 for separating a plurality of compounds in the sample in the time direction, and a column oven 12 for controlling the temperature of the column 13 . Note that the sample introduction part to the column 13 can be changed to one based on an appropriate method such as the headspace method.

The MS unit 1B has an ion source 15 that ionizes a target compound by an ionization method such as electron ionization (EI) and an ion lens that converges the generated ions in a chamber 14 that is evacuated by a vacuum pump (not shown). 16, a quadrupole mass filter 17 that separates ions according to the mass-to-charge ratio, a detection unit 18 that outputs a detection signal according to the amount of ions that have arrived, and an analog-to-digital converter that converts the detection signal into digital data. a section (ADC) 19; Here, a quadrupole mass filter is used as the mass separator, but other types of mass separators such as time-of-flight mass separators and ion traps may be used.

The control/processing unit 2 mainly has a function of controlling the operation of the measuring unit 1 and a function of processing the data obtained by the measuring unit 1. The control/processing unit 2 includes, as functional blocks, a library reading unit 20, an ion extraction unit 21, a database creation unit 22, a target analysis database 23, an analysis method creation unit 24, an analysis method storage unit 25, an analysis control unit 26, A data storage unit 27 and a compound identification unit 28 are included.

The substance of the control/processing unit 2 is a computer such as a personal computer, and the function of each functional block can be realized by executing control/processing software pre-installed in the computer on the computer. . In this case, the input unit 3 is a keyboard or pointing device (such as a mouse) attached to the computer, and the display unit 4 is a display monitor attached to the computer.

Spectral Library 5 is a kind of database that contains compound information for a large number of compounds. This compound information includes compound name, CAS registry number, molecular weight, molecular formula, structural formula, retention index (or retention time), and mass spectrum. As this spectral library 5, widely publicized spectral libraries such as those provided by NIST in the United States and Wiley in the United States can be used. It can be provided or created by the user himself.

　In the configuration shown in FIG. In addition, the spectrum library 5 is stored, for example, in an external server or the like that is separate from this system, that is, not included in this system, and this system accesses this server under legitimate authority, It can also be configured to download only necessary information from the server.

[Compound identification in the GC-MS system of the present embodiment]
Details of compound identification procedures and processing by target analysis in the GC-MS system of the present embodiment will be described.
FIG. 2 is a flow chart showing an example of the flow of compound identification. FIG. 3 is a flowchart showing an example of extraction processing of monitor ions and the like in FIG. FIG. 4 is an explanatory diagram of the registration procedure of the target analysis database. FIG. 5 is an explanatory diagram of the registered contents of the method file. FIG. 6 is a diagram showing an example of the relationship between mass spectra, monitor ions, and reference ions.

In target analysis, it is necessary to prepare in advance a target analysis database in which compound information about compounds that can be analyzed is registered. This target analysis database is created as follows.

The user first specifies the spectrum library 5 to be used for database creation through the input unit 3 (step S1). However, if only one spectrum library 5 is prepared, step S1 can be omitted.

The user determines the spectral library 5 from which the compound information is collected, and instructs the input unit 3 to read the compound information from the library 5 . Upon receiving this instruction, the library reading unit 20 reads compound information such as the compound name, mass spectrum, retention time (or retention index) from the spectral library 5 (step S2). Generally, the spectral library 5 contains compound information about a large number of compounds, but it is possible to collectively obtain compound information about all of the compounds, or to obtain specific information selected by the user. It may also be possible to obtain compound information only for a plurality of compounds of the above, or compound information only for a compound selected according to conditions specified by the user.

The database creation unit 22 registers the read compound information in the target analysis database 23 (step S3). FIG. 4A shows an example of the target analysis database 23 in which compound information has not yet been registered. In this example, the registration items are compound name, retention index, retention time, m/z value of monitor ion, m/z value of reference ion, and mass spectrum. Furthermore, registration items such as molecular formula may be added. When the registration process in step S3 is executed, as shown in FIG. 4B, the read compound information is input to each registration item of compound name, retention index, retention time, and mass spectrum. The retention time can be calculated from the retention index. At this point the m/z values of the monitor and reference ions are unknown.

Next, the ion extraction unit 21 executes a process of extracting monitor ions and reference ions from the mass spectrum registered for each compound as described above (step S4). This extraction processing will be described later in detail. Usually, there is one monitor ion and one or more reference ions. The database creation unit 22 registers m/z values of monitor ions and reference ions extracted for each compound in the target analysis database 23 (step S5). When the process of step S5 is executed, the m/z values of the extracted monitor ions and reference ions are registered in the target analysis database 23 as shown in FIG. Complete.

Next, when the user performs a predetermined operation on the input unit 3, the analysis method creation unit 24 displays the target analysis database 23 as shown in FIG. 4C on the screen of the display unit 4 in table format. do. The user thereby confirms the compound name, etc., and selects the target compound to be identified (step S6). FIG. 5A shows a state in which two compounds are selected as target compounds.

Then, when the user instructs creation of an analysis method, the analysis method creation unit 24 stores registration information such as the retention index of the compound selected as the target compound, m/z values of monitor ions and reference ions, etc. in the database 23 for target analysis. and based on the registered information, a method file of an analysis method including measurement conditions for GC/MS analysis and analysis conditions for each target compound is created (step S7).

The measurement conditions include, for example, the carrier gas flow rate in the GC section 1A, the temperature program of the column oven 12, the sample injection amount, and the m/z range of scan measurement in the MS section 1B. Further, the analysis conditions are basically the same as the information registered in the target analysis database 23, as shown in FIG. Including mass spectrum etc. The m/z range of the scan measurement can be determined to cover the m/z values of the monitor and reference ions for all target compounds. The created method file is stored in the analysis method storage unit 25 .

After creating the method file, when the user instructs the execution of analysis, the analysis control unit 26 controls the operation of the measurement unit 1 according to the measurement conditions included in the created method file. As a result, the GC/MS analysis of the target sample is performed in the measuring section 1 (step S8). That is, in the GC section 1A, the microsyringe 11 drops a predetermined amount of the target sample into the sample vaporization chamber 10 at a predetermined timing. The dropped target sample is vaporized in the sample vaporization chamber 10 and sent to the column 13 along with the carrier gas flow. Various compounds contained in the target sample are temporally separated while passing through the column 13 and introduced into the ion source 15 of the MS section 1B.

A compound introduced into the ion source 15 is ionized, and the generated ions are introduced into the quadrupole mass filter 17 through the ion lens 16 . Under the control of analysis control 26, quadrupole mass filter 17 operates to repeat scanning measurements over a predetermined range of m/z values. In this scan measurement, ions that have passed through the quadrupole mass filter 17 reach the detector 18, and the detector 18 outputs an ion intensity signal corresponding to the amount of ions that have arrived as a detection signal. Data obtained by digitizing this detection signal is sent to the control/processing unit 2 and stored in the data storage unit 27 .

After the analysis is completed, the compound identification unit 28 performs processing to identify each target compound based on the collected data. Specifically, the compound identification unit 28 first acquires ion intensity data at m/z values of monitor ions for each target compound, and creates an extracted ion chromatogram. This extracted ion chromatogram may be a waveform only for a predetermined time range including the retention time of the target compound. Then, the compound identification unit 28 detects peaks in the created extracted ion chromatogram, and acquires a measured mass spectrum at the retention time of the detected peak top. For example, if no significant chromatographic peak is detected in the extracted ion chromatogram, it is determined that the target compound is not contained.

When the measured mass spectrum is obtained, the compound identification unit 28 acquires the mass spectrum of the target compound registered in the method file as a reference mass spectrum, and determines the similarity of the pattern between the reference mass spectrum and the measured mass spectrum. Ask for degrees. A known method may be used to calculate this degree of similarity. Then, it is determined whether or not the degree of similarity is greater than or equal to a predetermined threshold, and if the degree of similarity is greater than or equal to the threshold, it is determined that the target compound is contained in the sample. Conversely, if the degree of similarity is less than the threshold, it is determined that the target compound is not contained in the sample. In this way, it is possible to confirm whether or not all target compounds are contained in the sample, that is, to identify the target compounds (step S9).

The procedure for compound identification by the compound identification unit 28 can be changed as appropriate. For example, when an extracted ion chromatogram is created for a certain target compound and no peak is detected near the retention time of the target compound in the extracted ion chromatogram, the compound exists, but other compounds overlap. There is also a possibility that peaks cannot be detected due to Therefore, if the peak could not be detected, create an extracted ion chromatogram at the m/z value of the reference ion of the target compound, and perform compound identification using the peak detected in the extracted ion chromatogram. may

Also, instead of final compound identification based only on the similarity between the reference mass spectrum and the measured mass spectrum, the ratio of the signal intensity of the monitor ion to the signal intensity of the reference ion in the measured mass spectrum, that is, confirmation Compound identification may be performed by also using the ion ratio.

[Extraction of monitor ions, etc. from mass spectrum]
An example of the ion extraction process in step S4 will be described with reference to FIGS. 3 and 6. FIG.
The ion extractor 21 first detects mass peaks from the mass spectrum (step S11), and obtains the intensity value of the mass peak indicating the maximum intensity (step S12). In the example of the mass spectrum shown in FIG. 6, the mass peak indicated by arrow P is the mass peak showing the maximum intensity, and its intensity value is Imax.

Next, the ion extraction unit 21 extracts mass peaks whose intensity value is 10% or more of the maximum intensity value among all the mass peaks detected in step S11 (step S13). This numerical value of "10%" is an example, and can be changed as appropriate. In the example of FIG. 6, the intensity value of Imax×0.1 is indicated by the dashed-dotted line A, and the mass peaks exceeding the peak intensity are indicated by ◯ marks.

The ion extraction unit 21 selects the mass peak with the largest m/z value as a monitor ion from among the mass peaks extracted in step S13 (step S14). Furthermore, among the mass peaks extracted in step S13, a predetermined number of mass peaks having an m/z value smaller than that of the monitor ion are selected as reference ions (step S15). Assuming that the number of reference ions is two, in the example of FIG. 6, the mass peak indicated by arrow M is selected as the monitor ion, and the mass peaks indicated by arrows R1 and R2 are selected as reference ions.

In steps S12 and S13, mass peaks with a certain intensity value or more are selected as candidates for monitor ions and reference ions because ions with relatively high detection sensitivity are selected as monitor ions and reference ions.

On the other hand, when an ionization method such as the EI method, which tends to generate fragments, is used as the ionization method, the intensity of fragment ion peaks with small m/z values tends to be high, and such mass peaks overlap in multiple compounds with similar chemical structures. easy. Therefore, if the mass peak with the maximum intensity value is simply selected as the monitor ion, there is a high possibility that multiple monitor ions of different compounds will overlap. On the other hand, the larger the m/z value of the mass peak, the more likely it is an ion peak resulting from desorption of protons from the compound molecule rather than a fragment ion peak. By selection, overlapping of monitor ions of different compounds can be avoided.

That is, by the processing of steps S14 and S15, it is possible to select monitor ions and reference ions that are well-balanced between high detection sensitivity and compound selectivity.
In addition, the procedure is substantially replaced with the above treatment, focusing only on mass peaks with m/z values above a certain level, such as m/z 50 or higher, and selecting mass peaks with high intensity values from among them to monitor ions. and reference ions may be determined. Thus, by using both the m/z value and the intensity value of the mass peak, it is possible to appropriately determine the monitor ion and the reference ion.

However, depending on the compound, a fragment ion and its isotope ion may be observed at high intensity. It will be selected as an ion and a reference ion. Even in that case, there is practically no problem. 5 Da, etc.) should be excluded from the selection of reference ions.

Further, the user may be allowed to set the conditions for the ion extractor 21 to extract monitor ions from the mass spectrum. An example will be described.
When the user performs a predetermined operation using the input unit 3, the ion extraction unit 21 displays a monitor ion extraction condition setting screen 6 on the screen of the display unit 4, an example of which is shown in FIG. The user inputs two parameters, "range of m/z" and "range of relative intensity" in this monitor ion extraction condition setting screen 6, and presses the OK button. As a result, the m/z value range for selecting monitor ions can be limited, and the intensity value threshold for selecting mass peaks can be appropriately determined.

As described above, in the GC-MS system of this embodiment, m/z values of monitor ions and reference ions used for compound identification are determined based on the mass spectrum of each compound recorded in the spectrum library. , can be determined without substantial burden on the user. In addition, the monitor ion thus determined for each compound is unlikely to overlap with other compounds and is detected with high sensitivity, so that the compound can be identified with high accuracy. .

[Modification]
In the GC-MS system of the above embodiment, the MS section 1B is a single-type mass spectrometer, but the MS section 1B is a triple quadrupole mass spectrometer or a quadrupole-time-of-flight mass spectrometer. A mass spectrometer capable of /MS analysis, or a mass spectrometer capable of MS ⁿ analysis where n is 3 or more, such as an ion trap mass spectrometer or an ion trap time-of-flight mass spectrometer, may be used. When an MS/MS type mass spectrometer is used, the m/z values of monitor ions and reference ions are replaced by a combination of precursor ion m/z values and product ion m/z values (that is, MRM transitions). be done.

In addition, in the GC-MS system of the above embodiment, the scan measurement was repeatedly performed in the MS part 1B, but selective ion monitoring (SIM) measurement targeting monitor ions and reference ions may be performed. In that case, when identifying a compound, the compound may be identified based on other information such as the confirming ion ratio, instead of the mass spectrum similarity.

Also, the above embodiment is an example in which the present invention is applied to GC-MS, but the present invention can also be applied to LC-MS and SFC-MS. However, the above-described processing for extracting monitor ions and the like from the mass spectrum is based on the premise that many fragment ions are generated during ionization of the mass spectrometer. Therefore, regardless of whether the mass spectrometer is preceded by GC, LC, or SFC, the ion source of the mass spectrometer should be an ionization method that tends to generate fragments (in other words, promote fragmentation). is preferred.

In addition, the above-described embodiment and various modifications are merely examples of the present invention, and it is clear that appropriate modifications, modifications, and additions within the spirit of the present invention are included in the scope of the claims of the present application. is.

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

(Section 1) One aspect of the chromatograph mass spectrometer according to the present invention is
a measurement unit including a chromatograph unit that separates the compounds in the sample in the time direction, and a mass spectrometry unit that detects each separated compound;
A mass spectrum of the target compound is obtained from a standard mass spectrum and a spectrum library containing compound information including retention time or retention index, and the intensity of the mass peak observed in the mass spectrum and the mass corresponding to the mass peak an ion extraction unit for extracting monitor ions for each target compound using the charge ratio value;
a database creating unit for registering in a database compound information of the target compound and mass-to-charge ratio values of monitor ions extracted by the ion extracting unit;
a compound designation reception unit that receives designation by a user of a target compound to be analyzed among the compounds registered in the database;
a method creation unit that creates an analysis method for the target compound using registered information in the database;
a control unit that controls the operation of the measurement unit so as to perform chromatographic mass spectrometry on a target sample according to the analysis method;
A compound identification unit that identifies a compound in the target sample by using the chromatographic mass spectrometry result for the target sample and the analysis method or registered information in the database;
Prepare.

In the chromatograph-mass spectrometer according to item 1, the user himself/herself analyzes a standard sample containing the target compound and extracts an appropriate monitor ion from the mass spectrum obtained for the target compound. The mass-to-charge ratio of monitor ions suitable for identifying the target compound is automatically extracted and registered in the database for analysis. As a result, according to the chromatograph mass spectrometer described in paragraph 1, while reducing the burden of complicated work by the user in target analysis for a large number of compounds, a large number of compounds can be obtained with high accuracy. can be identified.

(Section 2) In the chromatograph mass spectrometer according to Section 1, the compound identification unit creates an extracted ion chromatogram corresponding to monitor ions for each target compound, and in the extracted ion chromatogram, the retention index or Compounds may be identified by comparing mass spectra in peaks detected using retention times with mass spectra contained in the analytical method or registration information in the database.

With the chromatograph-mass spectrometer described in Item 1, it is possible to acquire monitor ions that have little overlap in mass-to-charge ratio values with monitor ions of other compounds. Therefore, in the extracted ion chromatogram created by the chromatograph mass spectrometer according to item 2, the chromatographic peak corresponding to the target compound contained in a trace amount in the sample can also be observed well, and the target compound A compound can be identified by using an actually measured mass spectrum in which the derived ions are sufficiently observed. Accordingly, compound identification can be performed with high accuracy.

(Section 3) In the chromatograph mass spectrometer according to Section 1 or Section 2, the ion extraction unit extracts peaks having a predetermined intensity value or more based on the intensity value of the peak showing the maximum intensity in the mass spectrum. Among them, the mass-to-charge ratio value corresponding to the peak having the largest mass-to-charge ratio value can be used as the mass-to-charge ratio value of the monitor ion.

According to the chromatograph-mass spectrometer according to the third item, the detection sensitivity is sufficiently high, and the possibility that the mass-to-charge ratio overlaps with ions derived from other compounds is small, that is, the selectivity of the compound is high. monitor ion can be selected. As a result, it is possible to improve the accuracy of compound identification when using this monitor ion to identify the compound.

(Section 4) In the chromatograph-mass spectrometer according to Section 3, extraction conditions for accepting a user's specification of the intensity range and the mass-to-charge ratio value range when extracting monitor ions in the ion extraction unit A designation reception unit may be further provided.

According to the chromatograph-mass spectrometer according to item 4, the user appropriately sets the conditions of the intensity range and the mass-to-charge ratio value range, so that more appropriate monitoring is performed in terms of both detection sensitivity and compound selectivity It is possible to select ions.

(Section 5) In the chromatograph mass spectrometer described in Section 3, the mass spectrometry unit may include an ion source based on an ionization method that promotes ion fragmentation.

Specifically, the ionization method that promotes ion fragmentation is, for example, the electron ionization method. When such an ionization method is used, fragment ion peaks derived from a plurality of compounds tend to overlap in regions where the mass-to-charge ratio is relatively small in the mass spectrum. Ion peaks tend to be observed without overlapping. Therefore, according to the chromatograph mass spectrometer described in item 5, as described above, the mass-to-charge ratio value corresponding to the peak having a relatively large mass-to-charge ratio value is selected as the mass-to-charge ratio value of the monitor ion. At times, the monitor ion can be less likely to overlap with other compounds.

(Item 6) In the chromatograph-mass spectrometer according to any one of items 1 to 5, the ion extractor corresponds to the intensity of the mass peak observed in the mass spectrum of the target compound and the mass peak. extracting one or more reference ions in addition to the monitor ion for each target compound using the mass-to-charge ratio value,
The database creation unit registers the mass-to-charge ratio value of the reference ion in the database,
The compound identification section may use the ratio of the intensity at the mass-to-charge ratio value of the monitor ion and the intensity at the mass-to-charge ratio value of the reference ion to identify the compound.

According to the chromatograph mass spectrometer according to item 6, for example, when overlapping of other compounds is suspected in monitor ions, an extracted ion chromatogram of reference ions is created instead of monitor ions, and the chromatogram can be used for compound identification. Accordingly, compound identification can be performed more reliably.

DESCRIPTION OF SYMBOLS 1... Measurement part 1A... Gas chromatograph (GC) part 10... Sample vaporization chamber 11... Micro syringe 12... Column oven 13... Column 1B... Mass spectrometry (MS) part 14... Chamber 15... Ion source 16... Ion lens 17... Four Heavy pole mass filter 18... Detection unit 2... Control/processing unit 20... Library reading unit 21... Ion extraction unit 22... Database creation unit 23... Target analysis database 24... Analysis method creation unit 25... Analysis method storage unit 26... Analysis control unit 27 Data storage unit 28 Compound identification unit 3 Input unit 4 Display unit 5 Spectrum library

Claims

a measurement unit including a chromatograph unit that separates the compounds in the sample in the time direction, and a mass spectrometry unit that detects each separated compound;
A mass spectrum of the target compound is obtained from a standard mass spectrum and a spectrum library containing compound information including retention time or retention index, and the intensity of the mass peak observed in the mass spectrum and the mass corresponding to the mass peak an ion extraction unit for extracting monitor ions for each target compound using the charge ratio value;
a database creating unit for registering in a database compound information of the target compound and mass-to-charge ratio values of monitor ions extracted by the ion extracting unit;
a compound designation reception unit that receives designation by a user of a target compound to be analyzed among the compounds registered in the database;
a method creation unit that creates an analysis method for the target compound using registered information in the database;
a control unit that controls the operation of the measurement unit so as to perform chromatographic mass spectrometry on a target sample according to the analysis method;
A compound identification unit that identifies a compound in the target sample by using the chromatographic mass spectrometry result for the target sample and the analysis method or registered information in the database;
A chromatograph mass spectrometer comprising.
The compound identification unit creates an extracted ion chromatogram corresponding to monitor ions for each target compound, mass spectrum at the peak detected using the retention index or retention time in the extracted ion chromatogram, and the analysis method or 2. The chromatograph mass spectrometer according to claim 1, wherein a compound is identified by comparing mass spectra included in registered information in said database.
The ion extraction unit monitors the mass-to-charge ratio value corresponding to the peak having the largest mass-to-charge ratio value among the peaks having a predetermined intensity value or more based on the intensity value of the peak indicating the maximum intensity in the mass spectrum. 2. The chromatograph mass spectrometer of claim 1, wherein the mass-to-charge ratio value is .
4. The mass chromatograph mass according to claim 3, further comprising an extraction condition designation reception unit that receives designation by a user of conditions for an intensity range and a mass-to-charge ratio value range when extracting monitor ions in the ion extraction unit. Analysis equipment.
The chromatograph mass spectrometer according to claim 3, wherein the mass analysis unit includes an ion source based on an ionization method that promotes ion fragmentation.
The ion extractor utilizes the mass peak intensity observed in the mass spectrum of the target compound and the mass-to-charge ratio value corresponding to the mass peak to extract one or more reference ions in addition to the monitor ion for each target compound. extract,
The database creation unit registers the mass-to-charge ratio value of the reference ion in the database,
2. The chromatograph-mass spectrometer according to claim 1, wherein said compound identification unit uses a ratio of the intensity at the mass-to-charge ratio value of the monitor ion and the intensity at the mass-to-charge ratio value of the reference ion to identify the compound.