JP6857569B2 - Mass spectrometry system and mass spectrum display method - Google Patents

Description

The present invention relates to mass spectrometry systems, in particular to the display of mass spectra.

A mass spectrometry system is used for mass spectrometry of samples such as organic compounds. The mass spectrometry system is generally composed of an ionization apparatus, a mass spectrometer, a data processing apparatus and the like. Among them, the mass spectrometer uses an electric field or a magnetic field to separate individual ions according to the mass-to-charge ratio m / z (m is the mass of the ion and z is the amount of charge of the ion) of each ion. Alternatively, it is extracted and a mass spectrum is generated from the detection results of individual ions. A data processing device is a device that analyzes or processes a mass spectrum. Mass spectra may also be generated in the data processing equipment.

Known mass spectrometry methods include time-of-flight type, quadrupole type, double-focusing type, ion trap type, and ion cyclotron type. As ionization methods, electron ionization (EI), chemical ionization (CI), atmospheric pressure chemical ionization (APCI), electrospray ionization (ESI), Etc. are known.

Recently, real-time direct analysis (DART) has been widely used. In DART, for example, plasma is generated from helium gas or the like by corona discharge, an excited neutral gas molecule is taken out from the plasma, and the sample is irradiated with the plasma to generate positive or negative ions of the sample. (See, for example, Patent Document 1). DART is a type of atmospheric pressure ionization method, and is positioned as a type of ambient analysis method because it can easily analyze various substances in the surrounding environment.

The sample to be subjected to mass spectrometry is derivatized prior to ionization, if necessary. That is, the sample is derivatized for the purpose of improving the sensitivity in mass spectrometry, adapting the sample properties to the selected ionization method, analyzing the composition or structure of the unknown sample, and the like. Known types of derivatization include methylation, trimethylsilyl (TMS) formation, and acetylation. As derivatization reagents, a large number of reagents are provided according to the combination of functional groups and derivatization types, that is, depending on the specific derivatization method (or derivatization conditions).

When a reagent is mixed with a sample (original sample) before derivatization, a reaction occurs at the functional groups contained in the sample, the structure of the functional groups is changed, and a derivatized sample (that is, a derivative) is produced. The derivatized sample is introduced into an ionizer, where sample ions are generated. The sample ions are introduced into the mass spectrometer. As a result, the mass spectrum of the derivatized sample can be obtained. Generally, with derivatization, the mass of the sample increases, that is, the observed m / z increases.

When the compound as a sample has, for example, two functional groups, in the first case where the two functional groups remain unreacted after derivatization, the reaction occurs only in one of the two functional groups. A second case in which the reaction occurs and a third case in which the reaction occurs at the two functional groups are conceivable. In the mass spectrum, three peaks can occur corresponding to three cases.

In the following, in some cases, the peak corresponding to the first case, that is, the peak corresponding to the non-reactive derivative (unchanged derivative) is referred to as “0th-order peak”, and the peak corresponding to the second case, that is, one reactive group. The peak corresponding to the derivative having (group generated by the reaction of the functional group) is referred to as "primary peak", and the peak corresponding to the third case, that is, the peak corresponding to the derivative having two reactive groups is referred to as "secondary peak". Let's call it "peak". The "0th-order peak" is also a peak corresponding to the sample before derivatization. Generally speaking, the nth-order peak is a peak corresponding to a compound having n reactive groups generated by the reaction of n functional groups.

Patent Document 2 discloses a technique for displaying an actually measured mass spectrum and a standard mass spectrum side by side. No description related to derivatization is found in Patent Document 2.

Japanese Unexamined Patent Publication No. 2014-21507 Japanese Unexamined Patent Publication No. 2011-237311

Both the mass spectrum of the original sample before derivatization and the mass spectrum of the derivatized sample after derivatization are usually observed in addition to one or more peaks to be observed. It contains multiple peaks that are not of interest. It is not easy to identify the observation target peak from a large number of peaks, or it is not easy to determine the presence or absence of an observation target peak from a large number of peaks.

An object of the present invention is to support the observation of a mass spectrum before or after derivatization. Alternatively, an object of the present invention is to support the observation of changes in the mass spectrum before and after derivatization. Alternatively, the purpose is to make it possible to easily identify the appearance positions of a plurality of observation target peaks arranged at a constant pitch after derivatization.

The mass spectrometry system according to the embodiment generates a first mass spectrum by mass spectrometry on the original sample before derivatization, and generates a second mass spectrum by mass spectrometry on the derivatized sample after the derivatization. A determination means for determining the amount of change per reacted functional group on the m / z axis based on the spectrum generating means to be used and the information specifying the derivatization method, and the amount of change are reflected. It includes a guide image generating means for generating a guide image, and a display means for displaying the guide image together with at least one of the first mass spectrum and the second mass spectrum.

According to the above configuration, a guide image is displayed together with one or both of the first mass spectrum (mass spectrum before derivatization) and the second mass spectrum (mass spectrum after derivatization). Desirably, the guide image is superimposed and displayed on the mass spectrum. The guide image is, for example, a graphic image generated based on the information specifying the derivatization method, and represents the amount of change per reacted functional group on the m / z (mass-to-charge ratio) axis. Is. For example, the guide image expresses the amount of peak shift caused by derivatization, the interval between a plurality of peaks caused by derivatization, and the like. If the guide image is displayed together with the first mass spectrum, it is possible to predict the appearance position of the peak generated after derivatization through the guide image. If the guide image is displayed together with the second mass spectrum, the appearance positions and interrelationships of the 0th-order peak, the 1st-order peak, and the like can be easily specified through the guide image.

According to the guide image, for example, various reagents can be selectively introduced into a sample having an unknown composition or structure, and the presence or absence of reaction (derivatization) for each reagent can be easily specified. Become. Through such work, it becomes possible to elucidate the type of functional group, the number of functional groups, and the like. Even in the presence of a large amount of noise, the guide image makes it easy to identify peaks to observe or note. It is also convenient because it is not necessary to sequentially calculate the mass increase after the functional group is changed to another group. The m / z axis is generally the horizontal axis of the mass spectrum. Here, m is the mass of the sample ion, and z is the amount of charge of the sample ion. If z is 1, m / z corresponds to the mass of the sample, in which case the amount of change corresponds to the mass. The concept of the mass spectrum after derivatization includes the mass spectrum obtained when derivatization is attempted but derivatization does not actually occur. The above amount of change is a concept that includes both an increase (increment) in mass and a decrease in mass.

In embodiments, the amount of change corresponds to an increment of mass per reacted functional group. In an embodiment, the guide image comprises at least one marker indicating where at least one peak appears. The marker is a symbol indicating a position on the m / z axis, and may be composed of, for example, a figure such as a line. The marker may be configured as a figure having a width in the direction of the m / z axis.

In the embodiment, the guide image corresponds to a derivative having a 0th-order marker indicating the appearance position of the 0th-order peak corresponding to the non-reactant and n (where n is an integer of 1 or more) reactive groups. It includes an nth-order marker indicating the appearance position of the next peak, and the distance between the 0th-order marker and the nth-order marker corresponds to n times the amount of change.

The mass spectrometric system according to the embodiment includes a correction means for correcting the display position of the guide image on the m / z axis based on the mass spectrum displayed together with the guide image. According to this configuration, even if an error occurs on the m / z axis when displaying the mass spectrum, the error can be eliminated. As a result, the appearance position of the peak can be displayed correctly.

In the embodiment, the correction means is a search means for searching for a specific peak included in the mass spectrum, and the m / m / so that the display position of the specific marker included in the guide image coincides with the generation position of the specific peak. An adjusting means for adjusting the display position of the guide image on the z-axis is included. The specific peak may be a 0th-order peak, a 1st-order peak, or a 2nd-order peak. Using that as a reference, a guide image containing a plurality of markers is generated based on the amount of change.

The mass analysis system according to the embodiment further includes a reagent information management table including a plurality of records corresponding to a plurality of reagents for derivatization, and the records for each reagent include information specifying the derivatization method. The determination means specifies the amount of change corresponding to the reagent used or used based on the reagent information management table.

The system according to the embodiment further includes a compound information management table including a plurality of records corresponding to a plurality of compounds, and the record for each compound contains information for specifying m / z before derivatization. The guide image generating means identifies the m / z before derivatization of the compound corresponding to the original sample based on the compound information management table, and the m / z before the derivatization and the change corresponding to the reagent. The guide image is generated based on the amount.

In the embodiment, the guide image generating means generates the guide image based on the user-designated position on the m / z axis and the amount of change. When a compound having an unknown composition or structure is used as a sample, it is difficult to automatically give a standard for reflecting the amount of change. Therefore, the user is asked to specify m / z as the standard.

The display method according to the embodiment reflects the step of determining the peak shift amount before and after derivatization on the m / z axis based on the information for identifying the reagent for derivatization, and the peak shift amount. The step of generating a guide image, the first mass spectrum generated by mass spectrometry on the original sample before the derivatization, and the first mass spectrometry generated by the mass spectrometry on the derivatized sample after the derivatization. The step of superimposing the guide image on at least one of the two mass spectra to generate a composite image and the step of displaying the composite image are included. The peak shift amount corresponds to, for example, the amount of change in m / z per reacted functional group, or corresponds to an integral multiple of the amount of change. If z is 1, the amount of change corresponds to the amount of change in m.

The above display method can be realized as a function of hardware or a function of software. In the latter case, a program for executing the above display method is installed in the mass spectrometric system or an information processing device included therein via a network or a portable storage medium.

According to the present invention, it is possible to support the observation of the mass spectrum before or after derivatization. Alternatively, according to the present invention, it is possible to support the observation of changes in the mass spectrum before and after derivatization. Alternatively, according to the present invention, the appearance positions of a plurality of observation target peaks arranged at a constant pitch after derivatization can be easily specified.

It is a block diagram which shows the mass spectrometry system which concerns on embodiment. It is a figure which shows the compound information management table. It is a figure which shows the reagent information management table. It is a figure for demonstrating how to obtain the appearance position of the peak which occurs after derivatization. It is a figure which shows the input screen in the 1st operation example. It is a figure which shows the guide image in the 1st operation example. It is a figure which shows an example of the analysis result of the mass spectrum. It is a figure which shows the 1st example of a peak search. It is a figure which shows the 2nd example of a peak search. It is a figure which shows the input screen in the 2nd operation example. It is a figure which shows the peak designation method in the 2nd operation example. It is a figure which shows the guide image in the 2nd operation example. It is a figure which shows the guide image which concerns on the 1st modification. It is a figure which shows the guide image which concerns on the 2nd modification.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a configuration example of the mass spectrometry system according to the embodiment. The illustrated mass spectrometry system 10 includes an ionization apparatus 12, a mass spectrometer 14, and a data processing apparatus 16.

The target of mass spectrometry is sample 11. Sample 11 is a known compound or an unknown compound. One or more derivatizing reagents to alter the properties of sample 11 (eg, to make it more volatile), to identify the composition or structure of sample 11, or for other purposes. (Hereinafter, simply referred to as "reagent") is used. If multiple reagents are used, they will be used sequentially. In FIG. 1, reference numeral 24 indicates reagent selection, and reference numeral 26 indicates supply of reagent to a sample, that is, derivatization.

In FIG. 1, reagents a1 to ai are exemplified as the selectable reagent group 22. Generally, reagents are prepared for each derivatization method, that is, for each combination of functional groups and derivatization types. Examples of the functional group include a carboxyl group, an amino group, a hydroxy group and the like. Examples of derivatization include methylation, trimethylation, acetylation and the like. For example, the carboxyl group -COOH is changed to _{-COOCH 3 by methylation.} At that time, the mass _{increases by 14u (CH 2} minutes). The amount of change in mass (unit change amount) per reacted functional group is hereinafter referred to as "incremental". When n functional groups react, the mass increases by n times the increment. The mass may decrease due to the reaction.

Usually, the mass spectrum of the sample before derivatization (original sample) is acquired, and then the mass spectrum of the sample after derivatization (derivatized sample) is acquired. In the process, changes in the mass spectrum (success or failure of derivatization, etc.) are observed. Hereinafter, the individual devices shown in FIG. 1 will be described in detail.

The ionization device 12 is a device that ionizes a sample. The illustrated ionizer 12 is based on real-time direct analysis (DART). DART is a type of atmospheric pressure ionization method that can easily analyze various substances. However, not all samples can be measured even in DART. When a sample that is difficult to measure is to be analyzed, it is necessary to change the properties of the sample so as to be suitable for DART. For this reason, derivatization is used. Of course, derivatization may be used for other purposes.

At the time of derivatization, for example, a sample (for example, 1 μl) is attached to the tip of a glass rod, and then a reagent (for example, 1 μl) is further given to the tip. After that, the tip provided with the mixture of the sample and the reagent is inserted into a predetermined position (flow of the neutral gas molecule in the excited state) in the ionizing apparatus 12. This produces sample ions. The glass rod is an example of a member that supports a sample or the like, and a cotton swab or the like may be used instead of the glass rod. An ionization method other than DART may be used. As other ionization methods, an electron ionization method, a chemical ionization method, an atmospheric pressure chemical ionization method, an electrospray ionization method and the like are known.

The mass spectrometer 14 uses an electric field or a magnetic field to separate or extract individual ions according to the m / z (mass-to-charge ratio) of each ion, and generates a mass spectrum from the detection results of the individual ions. Is what you do. The mass spectrometer 14 constitutes a mass spectrum generating means. A mass spectrum may be generated on the data processing device 16 side based on the detection data output from the mass spectrometer 14. The mass spectrometer 14 is, for example, a time-of-flight mass spectrometer. As other mass spectrometry methods, a quadrupole type, a double-focusing type, an ion trap type, an ion cyclotron type and the like are known. In the configuration example shown in FIG. 1, spectrum data 17 is sent from the mass spectrometer 14 to the data processing device 16.

The data processing device 16 is a device composed of an information processing device (for example, a personal computer) including a CPU and a program, and analyzes or processes input spectrum data. An input device 18 including a keyboard, a mouse, and the like, and a display device 20 including a CRT and the like are connected to the data processing device 16. They make up the user interface.

In FIG. 1, a plurality of functions possessed by the data processing device 16 are represented by a plurality of blocks. Each block corresponds to a software function. However, each block may be configured by a processor as dedicated hardware. Specifically, the data processing device 16 includes a compound information management unit 28, a reagent information management unit (incremental determination unit) 30, a peak search unit 34, a guide image generation unit 36, a display processing unit 38, an analysis unit 40, and the like. .. Each will be described below.

The compound information management unit 28 has a compound information management table, and specifies the m / z before derivatization, the number of functional groups N, and the like for the compound based on the information for specifying the compound as a sample.

FIG. 2 illustrates the compound information management table 28A. The compound information management table 28A comprises a plurality of records 41 corresponding to a plurality of compounds. The record 41 corresponding to each compound contains a plurality of pieces of information, and specifically includes compound name 42, composition formula 44, precision mass 45, pre-derivatization m / z 46, functional group name 48, number of functional groups 50, and the like. .. From the information for specifying the compound (for example, compound name 42), the m / z before derivatization, the number of functional groups N, and the like are specified for the compound. The pre-derivatization m / z is information for specifying the appearance position of the sample peak (corresponding to the 0th-order peak) included in the mass spectrum before derivatization. The number of functional groups is the number of functional groups possessed by the compound, in other words, the maximum number of functional groups to react with. When an unknown compound is to be analyzed, for example, m / z before derivatization is specified by the user on the mass spectrum. This will be described later. When one compound has a plurality of types of functional groups, the functional group name and the number of functional groups are controlled for each functional group.

In FIG. 1, the reagent information management unit 30 has a reagent information management table, and is on the m / z axis based on information for specifying the reagent to be used or used (or information for specifying the derivatization method). , The increment Δ per reacted functional group is obtained. The reagent information management unit 30 functions as an incremental determination means.

FIG. 3 illustrates the reagent information management table 30A. The reagent information management table 30A is composed of a plurality of records 51 corresponding to a plurality of reagents. The record 51 corresponding to each reagent contains a plurality of information, specifically, the derivatization reagent name 52, the functional group 54 to be reacted, and the increment Δ per reaction functional group on the m / z axis. Etc. are included. If the reagent is specified, the increment Δ when derivatization is performed using the reagent is specified from the reagent information management table 30A. This increment Δ forms the basic unit of mass increase, and indicates the peak interval corresponding to one reactive group in the mass spectrum after derivatization. When one reagent reacts with a plurality of functional groups, the increment Δ is controlled for each functional group.

In FIG. 1, the guide image generation unit 36 functions as a guide image generation means. The guide image is an image for supporting spectrum observation that is superimposed and displayed on the mass spectrum before derivatization or the mass spectrum after derivatization, and includes, for example, a marker sequence. For example, the marker sequence includes a 0th-order marker indicating the appearance position of the 0th-order peak corresponding to the non-reactant, a primary marker indicating the appearance position of the 1st-order peak corresponding to the derivative having one reactive group, and two markers. Includes a secondary marker, which indicates the location of the secondary peak corresponding to the derivative having a reactive group. The guide image may contain display elements other than markers.

The appearance position of the 0th-order peak can be specified as the m / z specified by the compound information management unit 28, or as the 0th-order peak position specified by the user on the m / z axis. However, the user may specify the primary peak position, the secondary peak position, and the like. This will be described later. The primary peak position is specified by adding an increment Δ to the 0th-order peak position, that is, the underlying m / z. The secondary peak position is specified by further adding the increment Δ.

FIG. 4 shows a calculation method for obtaining the i-th order peak position. Here, i is an integer of 1 or more and a maximum value of N or less, and indicates the number of reacted functional groups. The post-derivatization m / z 60 is calculated by adding an increment Δ × i to the pre-derivatization m / z 62. By substituting each integer value from 1 to N for i, it is possible to sequentially specify the primary peak position, the secondary peak position, the tertiary peak position, and so on. As will be described later, when the first-order peak position is specified by the user, the 0th-order peak may be specified by subtracting the increment Δ from that as a reference. In that case, the calculation formula shown in FIG. 4 may be used, and for example, -1 may be substituted for i.

In FIG. 1, the guide image generation unit 36 has a function of calculating or specifying a plurality of m / z as described above, and a function of generating a guide image composed of a plurality of markers representing the plurality of m / z. .. The generated guide image is a graphic image, which is sent to the display processing unit 38. The display processing unit 38 functions as a display processing means and has an image composition function. Specifically, a display image (composite image) is generated by superimposing a guide image on the mass spectrum. The display image is displayed on the display 20.

The mass spectrum before derivatization and the guide image may be synthesized, or the mass spectrum after derivatization and the guide image may be synthesized. The mass spectrum before derivatization, the mass spectrum after derivatization, and the guide image may be synthesized. The mass spectrum at the time when the time t1 after the introduction of the reagent has elapsed, the mass spectrum at the time when the time t2 after the introduction of the reagent has elapsed, and the guide image may be synthesized. Using the input device 18, the user inputs information for specifying the compound, information for specifying the reagent, a specific position on the m / z, and the like. The analysis unit 40 performs necessary analysis such as area calculation on the mass spectrum.

The data processing device 16 has a peak search unit 34 that functions as a peak search means and an adjustment unit that functions as an adjustment means. In the illustrated configuration example, the adjusting unit is one of a plurality of functions of the guide image generating unit 36. The peak search means and the adjusting means constitute a correction means.

Specifically, the peak search unit 34 searches for a specific peak within a constant width centered on a specific m / z on the mass spectrum. The specific m / z is one of the plurality of m / z calculated as described above. The specific peak is, for example, a 0th-order peak. Other peaks may be searched. For example, when the mass spectrum to be analyzed is the mass spectrum after derivatization, the primary peak may be the search target. The guide image generation unit 36 shifts the entire guide image along the m / z axis so that the position of the specific marker in the guide image coincides with the specific peak. That is, the guide image generation unit 36 has a correction function by peak fitting. A specific example will be described later.

According to the above correction function, even if the position of the mass spectrum shifts on the m / z axis due to some reason such as measurement error, the guide image is superimposed on the mass spectrum with the correct positional relationship. It becomes possible to display. That is, it is possible to correctly align a plurality of markers constituting the guide image with a plurality of peaks. This makes it possible to prevent erroneous peaks from being identified or observed through the guide image. It should be noted that a plurality of markers may be aligned with the plurality of peaks. The entire mass spectrum may be shifted so that specific peaks in the mass spectrum coincide with the specific markers that make up the guide image.

Next, a first operation example will be described with reference to FIGS. 5 and 6. FIG. 5 shows an input screen 70. On the input screen 70, a field 72 for inputting a composition formula, a field 74 for inputting the name of the derivatizing reagent, a field 76 for inputting the maximum number of functional groups to be derivatized, and an operation when performing correction by peak fitting are performed. A button 78 to be input, an execution button 80 for instructing the generation of a guide image, and the like are included. Information for identifying the sample compound is input using column 72. Based on the information, the m / z of the compound is automatically specified, and the maximum value of the reactive group is automatically specified. For the latter, the maximum value may be manually specified by inputting to the column 76. Information for identifying the reagent is input using the field 74. Based on that information, the increment Δ per functional group is automatically identified. A guide image is generated based on the plurality of information identified in this way.

A display example is shown in FIG. The displayed image has a mass spectrum 82 after derivatization and a guide image 84. The horizontal axis of the mass spectrum 82 is the m / z axis. The vertical axis shows the relative strength. X indicates the m / z of the sample before derivatization (or the m / z of the non-reactant). The sample has, for example, two functional groups. X'1 indicates the m / z of the derivative having one reactive group. X'2 indicates the m / z of the derivative having two reactive groups.

The guide image 84 includes three markers M0, M1 and M2 arranged at equal intervals. Specifically, the marker M0 is a 0th-order marker, which indicates the appearance position (that is, X) of the 0th-order peak PW0. The marker M1 is a primary marker, which indicates the appearance position (that is, X'1) of the primary peak PW1. The marker M2 is a secondary marker, which indicates the appearance position (that is, X'2) of the secondary peak PW2. The distance 86A between the 0th-order marker M0 and the 1st-order marker M1 corresponds to the increment Δ. Similarly, the distance 86B between the primary marker M1 and the secondary marker M2 also corresponds to the increment Δ.

Each of the markers M0, M1 and M2 has a vertical linear shape. The morphology of each marker M0, M1, M2 may be changed to another. For example, it may be a triangular symbol. In that case, the tip of the symbol points to a specific m / z. Each marker M0, M1, M2 may be a strip-shaped line having a constant width. The colors or morphologies of the markers M0, M1 and M2 may be different from each other. In the display example shown in FIG. 6, the markers M0, M1 and M2 coincide with the peaks PW0, PW1 and PW2, and the above correction is not necessary. When correction is required, the button 78 shown in FIG. 5 is operated before or after.

If the guide image is superimposed on the mass spectrum before derivatization, the appearance positions of the primary peak and the secondary peak that occur after derivatization can be recognized in advance. Then, if a reagent is given to the sample, it is possible to accurately identify the gradually growing primary peak and secondary peak, and it is possible to judge the presence or absence of derivatization early or correctly. It becomes.

FIG. 7 shows an example of the analysis result of the mass spectrum. The ionic strength is analyzed as the peak height or peak area for each peak, and the presence or absence of the ionic strength is determined for each peak. When the peak apex exceeds the threshold value (see reference numeral 87 in FIG. 6), it is determined that there is a peak (Y), and in the opposite case, it is determined that there is no peak (N). Also in such mass spectrum analysis, pre-calculated X, X'1 and X'2 are used.

Next, the peak fitting correction will be specifically described with reference to FIGS. 8 and 9. FIG. 8 shows the mass spectrum 82 after derivatization. X indicates the theoretical m / z for the sample. The position is indicated by line 90. Y indicates the position of the measured 0th-order peak PW0, and specifically indicates the position of the apex P0. Y'1 and Y'2 indicate the positions of the primary peak and the secondary peak, respectively. When performing peak fitting correction, first, a peak search range 92 having a constant width centered on X is determined. Within the peak search range 92, the apex P0 of the 0th-order peak PW0 is searched. After that, the entire position of the guide image is adjusted so that the 0th-order marker M0 coincides with the vertex P0. After the adjustment, the primary marker M1 coincides with the position Y'1 of the primary peak, and the secondary marker M2 coincides with the position Y'2 of the secondary peak. The interval 96A between Y and Y'1 and the interval 96B between Y'1 and Y'2 both correspond to the increment Δ. A threshold value 94 may be set when searching for the vertex P0. That is, the highest point in the waveform exceeding the threshold value 94 may be recognized as the vertex P0. Instead of the apex P0, a representative point such as the center of the peak PW0 and the center of gravity may be searched.

As shown in FIG. 9, the primary peak PW1 may be the search target. X'1 indicates the calculated primary peak appearance position. Its position is indicated by line 100. Y indicates the position of the measured 0th-order peak PW0, and specifically indicates the position of the apex P0. Y'1 and Y'2 indicate the positions of the primary peak and the secondary peak, respectively. A peak search range 102 having a constant width centered on the line 100 is set, and the apex P1 of the primary peak PW1 is searched within the peak search range 102. In that case, for example, the highest point in the waveform exceeding the threshold value 104 is considered to be the vertex P1. If the vertex P1 cannot be found, error processing is executed. The appearance position Y'1 of the primary peak and the appearance position Y'2 of the secondary peak are specified with reference to the position of the searched vertex P1. The distance 106A between Y and Y'1 and the distance 106B between Y'1 and Y'2 both correspond to the increment Δ. Peak fitting correction may be executed using peaks other than the above, or peak fitting correction may be executed using a plurality of peaks.

Next, a second operation example will be described with reference to FIGS. 10 to 12. FIG. 10 shows an input screen 110. On the input screen 110, a field 112 for inputting the precise mass, a field 114 for inputting the name of the derivatizing reagent, a field 116 for inputting the order (index) of the designated peak, and the maximum number of functional groups to be derivatized are input. Column 118, a button 120 operated when performing correction by peak fitting, an execution button 122 instructing generation of a guide image, and the like are included. Using the column 112, a reference m / z, for example, m / z corresponding to the position of the primary peak is input. In the illustrated example, X'1 is input as a numerical value. When the amount of charge is 1, the precise mass corresponds to m / z. Information for identifying the derivatizing reagent is entered using field 114. The order of the designated peak is input using the field 116. For example, when it is desired to use the primary peak as a reference, 1 is input in the field 116. The maximum value of the functional group is input using the field 118. In the illustrated example, 2 is input. Markers for the number of markers obtained by adding 1 to the value are displayed. Instead of inputting the precise mass, that is, m / z as a numerical value, the user may specify a reference m / z on the m / z axis as shown in FIG. For example, the cursor 124 may be used to specify it.

Based on the information input as described above, as shown in FIG. 12, a guide image 126 is generated, and the guide image 126 is superimposed and displayed on the mass spectrum 82. The guide image 126 is based on the user-specified primary marker M1 indicating X'1, the 0th-order marker M0 located 128A to the left of the X'1, and the X'1. Includes a secondary marker M2, which is located to the right by an interval of 128B from it. The intervals 128A and 128B both correspond to the increment Δ.

For example, when analyzing the composition or structure of an unknown sample, it is conceivable to perform the above analysis process for each selected reagent. Derivatization with the selected reagent can be confirmed if multiple peaks actually occur at the multiple peak appearance positions specified by the guide image. Based on this, it is possible to specify the type and number of functional groups possessed by the unknown sample. In both the first operation example and the second operation example, a guide image reflecting the increment Δ corresponding to the reagent is displayed, and the observation of the mass spectrum can be supported by the guide image.

FIG. 13 shows a first modification. The guide image 126 is superimposed and displayed on the mass spectrum 82A. The guide image 126 is the same as that shown in the first operation example and the second operation example. On the other hand, the mass spectrum 82A is composed of only the 0th-order peak PW0, the 1st-order peak PW1 and the 2nd-order peak PW2, and the other plurality of peaks are eliminated. That is, based on the specified X, X'1, X'2, or a plurality of markers M0, M1, M2 representing them, a discrimination process of leaving or eliminating each peak is applied, and as a result, a discrimination process is applied. , Mass spectrum 82A is formed. In this way, the mass spectrum may be processed using the reference m / z and the increment Δ.

FIG. 14 shows a second modification. The guide image 136 is synthesized on the mass spectrum 130. The mass spectrum 130 is generated by synthesizing the mass spectrum 132 before derivatization and the mass spectrum 134 after derivatization. In order to distinguish between the two, the mass spectra 132 and 134 may be colored with different colors. Alternatively, the two mass spectra 132, 134 may be identified by other methods. After the initiation of derivatization, the level of the 0th-order peak identified by the 0th-order marker M0 decreases, while the primary and secondary peaks identified by the primary and secondary markers M1 and secondary markers appear. Also, their levels increase. In the observation process, it is possible to correctly and easily identify a plurality of peaks to be observed by using the 0th-order marker M0, the 1st-order marker M1 and the 2nd-order marker M2 constituting the guide image 136 as a guide.

According to the above embodiment, it is possible to support the observation of the mass spectrum before or after derivatization. In particular, it can support the observation of changes in the mass spectrum before and after derivatization. In addition, the appearance positions of a plurality of observation target peaks arranged at a constant pitch after derivatization can be accurately and easily specified.

10 Mass spectrometric system, 12 Ionizer, 14 Mass spectrometer, 16 Data processing device, 28 Compound information management unit, 30 Reagent information management unit, 34 Peak search unit, 36 Guide image generation unit, 38 Display processing unit, 82 Mass spectrum , 84 Guide image.

Claims (10)

A spectrum generating means for generating a first mass spectrum by mass spectrometry on the original sample before derivatization and generating a second mass spectrum by mass spectrometry on the derivatized sample after the derivatization.
A determination means for determining the amount of change per reacted functional group on the m / z axis based on the information specifying the derivatization method.
A guide image generating means for generating a guide image reflecting the amount of change, and
A display means for displaying the guide image together with at least one of the first mass spectrum and the second mass spectrum.
A mass spectrometry system characterized by including. In the system according to claim 1,
The amount of change corresponds to an increment of mass per reacted functional group.
A mass spectrometry system characterized by this. In the system according to claim 1,
The guide image includes at least one marker indicating the appearance position of at least one peak.
A mass spectrometry system characterized by this. In the system according to claim 1,
The guide image is
A 0th-order marker indicating the appearance position of the 0th-order peak corresponding to the non-reactant, and a 0th-order marker.
An nth-order marker indicating the appearance position of the nth-order peak corresponding to a derivative having n (where n is an integer of 1 or more) reaction groups,
Including
The distance between the 0th-order marker and the nth-order marker corresponds to n times the amount of change.
A mass spectrometry system characterized by this. In the system according to claim 1,
A correction means for correcting the display position of the guide image on the m / z axis based on the mass spectrum displayed together with the guide image is included.
A mass spectrometry system characterized by this. In the system according to claim 5,
The correction means
A search means for searching for a specific peak included in the mass spectrum, and
An adjusting means for adjusting the display position of the guide image on the m / z axis so that the display position of the specific marker included in the guide image coincides with the generation position of the specific peak.
A mass spectrometry system characterized by including. In the system according to claim 1,
Contains a reagent information management table consisting of multiple records corresponding to multiple reagents for derivatization.
The record for each reagent includes reagent identification information as information for specifying the derivatization method and information for specifying the amount of change.
The determination means specifies the amount of change corresponding to the reagent used or used based on the reagent information management table.
A mass spectrometry system characterized by this. In the system according to claim 7,
Contains a compound information management table consisting of multiple records corresponding to multiple compounds
The record for each compound contains information for identifying m / z before derivatization.
The guide image generating means identifies the m / z before derivatization of the compound corresponding to the original sample based on the compound information management table, and the m / z before the derivatization and the change corresponding to the reagent. Generate the guide image based on the amount and
A mass spectrometry system characterized by this. In the system according to claim 1,
The guide image generating means generates the guide image based on the user-designated position on the m / z axis and the amount of change.
A mass spectrometry system characterized by this. A step of determining the peak shift amount before and after derivatization on the m / z axis based on the information for identifying the reagent for derivatization, and
A step of generating a guide image reflecting the peak shift amount and
At least one of the first mass spectrum generated by mass spectrometry on the original sample before derivatization and the second mass spectrum generated by mass spectrometry on the derivatized sample after derivatization. On the other hand, the step of superimposing the guide image and generating a composite image by this,
The process of displaying the composite image and
A mass spectrum display method comprising.

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