JPH04296434A - Chromatograph/mass spectrometer - Google Patents

Abstract

PURPOSE:To automatically produce a mass chromatogram excellent in selectivity by reading out a mass spectrum corresponding to a designated component peak, and sending it in the priority order of the mass number to a mass chromatogram producing portion. CONSTITUTION:Sample gas introduced into a gas chromatograph 2 is ionized, to be introduced into a mass spectrometer 3. Data obtained in the spectrometer 3 is stored in a mass spectrum data memory 4. When a designator 12 designates a desired component peak position of the total ion chromatogram, a controller 16 reads out a mass spectrum data corresponding to the designated component peak position from the memory 4, to transfer it to an MC display priority determining portion 14. The priority determining portion 14 gives priority to ions in the order of peak strength or mass number, to thereby send data of the mass number to an MC producing portion 8. The MC producing portion 8 produces the mass chromatogram in sequence each time the mass number is selected in the priority order, thus sending it to a display 10.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a chromatograph/mass spectrometer that connects various chromatographs such as gas chromatographs and liquid chromatographs to a mass spectrometer, and particularly relates to a selective display of mass chromatograms. Regarding technology.

0002

[Prior Art] In general, a chromatograph/mass spectrometer that connects various chromatographs such as gas chromatographs and liquid chromatographs to a mass spectrometer performs qualitative and quantitative analysis of each substance contained in a sample. In some cases, there are analytical techniques that measure mass chromatograms (MC).

[0003] The measurement of this mass chromatogram is usually carried out by
This is done as follows.

First, the mass spectrum of an ionized sample is measured by repeatedly performing mass scanning over a predetermined mass number range at regular time intervals, and after storing all the data of each mass spectrum in memory, these mass spectra are Based on the spectral data, a specific mass number of the substance to be analyzed is set, and a curve of the change in ion intensity over time for the set mass number is drawn, and this is obtained as a mass chromatogram.

[0005] This analysis method is particularly effective when analyzing a multi-component sample because even components that cannot be separated by chromatography can be separated by mass number.

By the way, in the measurement of this mass chromatogram, the most important thing is to set the mass number of the target substance to be analyzed, and if this setting is incorrect or inappropriate, the peak intensity may be low or the peak may be distorted. Accurate analysis results cannot be obtained due to poor resolution, etc.

Conventionally, to set the mass number to obtain a mass chromatogram, a so-called total ion chromatogram (TIC), which shows the change over time of the intensity signal obtained by summing the mass spectrum data of all ions, is displayed on a screen such as a CRT. Then, specify the position of one component peak included in the TIC. Then, one mass spectrum corresponding to the component peak position is called up on the screen, and from that mass spectrum, one with a large peak intensity, or
The mass number (m/z) of each ion showing a characteristic peak, such as one with a large mass number, is read and set.

[0008]

[Problem to be Solved by the Invention] Conventionally, in order to select a mass number, an analyst specifies one component peak in a total ion chromatogram and looks at the mass spectrum contained in this component peak. It is necessary to specify the mass number each time, which makes the operation for selecting the mass number complicated and time-consuming.

[0009]

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems, and provides a mass chromatography system with good selectivity by making it easier to select the mass number than before. program is automatically created.

Therefore, in the present invention, there is provided a mass spectral data storage section 4 that stores mass spectral data obtained by repeatedly performing mass scanning over a predetermined mass number range at regular time intervals on an ionized sample, and A TIC that creates a total ion chromatogram showing changes in total ion intensity over time based on mass spectrum data stored in the data storage unit 4
a creation unit 6 and an MC creation unit 8 that creates a mass chromatogram showing a temporal change in ion intensity for a specific mass number based on the data of each mass spectrum stored in the mass spectrum data storage unit 4; A chromatograph/mass spectrometer equipped with a display section 10 that displays a total ion chromatogram created by the TIC creation section 6 and a mass chromatogram created by the MC creation section 8, respectively, has the following configuration.

That is, the chromatograph/mass spectrometer of the present invention includes a specifying means 12 for specifying a desired component peak position of a total ion chromatogram, and one of the peak positions of the total ion chromatogram specified by the specifying means 12. Regarding the mass spectrum at the component peak position, priority is given to the ion in descending order of peak intensity or in descending order of mass number, and the data of the mass number is transmitted to the MC in descending order of priority.
The MC display priority determining unit 14 sends data to the creating unit 8, and according to the specification of the peak position by the specifying unit 12, data of one mass spectrum corresponding to this is read out from the mass spectrum data storage unit 4 and is given priority for MC display. Degree determination section 14
and a control section 16 that gives a mass spectrum creation command to the MC creation section 8 every time mass number data is sent from the MC display priority determination section 14.

0012

[Operation] In the above configuration, when a target component peak is designated by the designation means 12, the control section 16 reads out a mass spectrum corresponding to the component peak from the mass chromatogram data storage section 4 in response to this. The MC display priority determining unit 14 assigns priorities to ions in descending order of peak intensity or in descending order of mass number, and then transfers them to the MC display priority determining section 14. The data are sent to the MC creation unit 8 in descending order of mass number. The MC creation unit 8 sequentially creates mass chromatograms corresponding to these selected mass numbers.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of an embodiment of the present invention.

[0014] In the figure, numeral 1 indicates a chromatograph/
The entire mass spectrometer is shown, and 2 is a gas chromatograph that separates sample gas into components, and 3 is a quadrupole type or double convergence type mass spectrometer.

4 is a mass spectrum data storage unit that stores mass spectrum data obtained by repeatedly performing mass scanning over a predetermined mass number range at regular time intervals on an ionized sample; 6 is a mass spectrum data storage unit 4; A TIC creation section 8 creates a total ion chromatogram showing changes in total ion intensity over time based on the stored mass spectrum data; Create a mass chromatogram showing the change in ion intensity over time for a specific mass number based on the MC
The creation unit 10 is a display unit that displays the total ion chromatogram created by the TIC creation unit 6 and the mass chromatogram created by the MC creation unit 8, respectively.

Reference numeral 12 denotes a specifying means such as a keyboard or a mouse for specifying the desired component peak position of the total ion chromatogram.

14 prioritizes the mass spectrum at the peak position of one component in the total ion chromatogram specified by the specifying means 12 in descending order of the peak intensity of the ion, and This is an MC display priority determination unit that sequentially sends the mass number data to the MC creation unit 8.

16 reads data of one mass spectrum corresponding to the peak position specified by the specifying means 12 from the mass spectral data storage unit 4,
This is a control section that sends the data to the C display priority determination section 14 and also gives a mass spectrum creation command to the MC creation section 8 every time mass number data is sent from the MC display priority determination section 14.

Next, the operation of each part in the above configuration will be explained.

The sample gas introduced into the gas chromatograph 2 is separated into components here, and then ionized by an ionization means such as electron impact (not shown) and then transferred to the mass spectrometer 3.
will be introduced in

In the mass spectrometer 3, mass scanning is repeatedly performed on the ionized sample over a predetermined mass number range at regular time intervals, and the mass spectrum data obtained thereby is stored in the mass spectrum data storage section 4. Ru.

Next, when a command to display the total ion chromatogram is given from the specifying means 12, the control section 16
In response to this, the TIC creation section 6 is started, so the TIC
The creation section 6 creates a total ion chromatogram showing the change in total ion intensity over time based on the mass spectrum data stored in the mass spectrum data storage section 4, and outputs this data to the display section 10. As a result, a total ion chromatogram as shown in FIG. 2(a) is displayed on the screen of the display unit 10.

Therefore, next, the specifying means 12 moves the cursor (
20 (arrow in FIG. 2(a)) to obtain a target component peak (in this example, the peak indicated by the symbol P3)
In response to this, the control unit 16 reads out the corresponding mass spectrum data (see FIG. 3) at the position of the component peak P3 from the mass chromatogram data storage unit 4 and sends it to the MC display priority determination unit. Transfer to 14.

The MC display priority determination unit 14 sets a preset threshold value I for this mass spectrum data.
Ions with an intensity greater than or equal to sh (in this example, mass number (m/
z)2, (m/z)4, (m/z)5, and (m/z)7), as shown in Figure 4(a), ions with large peak intensities Prioritize things in order. In this example, the peak intensity of the ion with mass number (m/z) 4 is the highest, so it has the highest priority, and below, (
The order is m/z)2→(m/z)5→(m/z)7. Then, the MC creation unit 8
Send to. Every time a mass number is selected in the order of priority, the MC creation section 8 sequentially creates a mass chromatogram regarding that mass number, and sends the data of each mass chromatogram to the display section 10. Therefore, mass chromatograms are displayed on the screen of the display unit 10 in descending order of priority from top to bottom, as shown in FIG. 2(b). In this example, (m/z)4→(m/z)2→(m
The mass chromatograms are displayed in the order of /z)5→(m/z)7.

Each mass chromatogram (m/
If it is not possible to display z)4 to (m/z)7 all at once, for example, it is possible to display the mass chromatograms one by one each time a command to update the display of the mass chromatogram is given from the specifying means 12. good.

These mass chromatograms (m/z) 4
By observing ~(m/z)7, it can be easily determined what mass number gives the optimal mass chromatogram for this component.

[0027] In this example, priority is given in descending order of mass number of ion intensity; however, since higher ion intensity does not necessarily mean better peak separation, depending on the case, As shown in Figure 4(b), in descending order of mass number (in this example,
m/z)7→(m/z)5→(m/z)4→(m/z)
2) may be prioritized.

Furthermore, in this example, the case where a gas chromatograph is used for component separation has been explained, but the present invention is not limited to this, and the present invention can also be applied to other chromatographs such as a liquid chromatograph. Of course, it can be applied.

[0029]

[Effects of the Invention] According to the present invention, the selection of mass numbers is automatically performed in order of priority, so the effort of selecting mass numbers can be saved, and a mass chromatogram with good selectivity can be created. Become.

[Brief explanation of drawings]

FIG. 1 is a block diagram according to an embodiment of the present invention.

FIG. 2 is a total ion chromatogram and a mass chromatogram measured with the apparatus of FIG. 1.

FIG. 3 is an explanatory diagram showing one mass spectrum at a peak position of a total ion chromatogram.

FIG. 4 is an explanatory diagram showing the operation of an MC display priority determining section.

[Explanation of symbols]

1... Chromatograph/mass spectrometer, 4... Mass spectrum data storage unit, 6... TIC creation unit, 8... MC creation unit,
DESCRIPTION OF SYMBOLS 10...Display unit, 12...Specifying means, 14...MC display priority determination unit, 16...Control unit.

Claims (1)

[Claims] 1. A mass spectral data storage unit (4) that stores mass spectral data obtained by repeatedly performing mass scanning over a predetermined mass number range at regular time intervals on an ionized sample; A TIC creation section (6) that creates a total ion chromatogram showing changes in total ion intensity over time based on the mass spectrum data stored in the section (4).
), and an MC creation unit (8) that creates a mass chromatogram showing a temporal change in ion intensity for a specific mass number based on the mass spectrum data stored in the mass spectrum data storage unit (4). and a display section (10) that displays the total ion chromatogram created by the TIC creation section (6) and the mass chromatogram created by the MC creation section (8), respectively. In the analyzer, a specifying means (12) for specifying a desired component peak position of the total ion chromatogram, and a mass spectrum at one component peak position of the total ion chromatogram specified by the specifying means (12). , an MC that prioritizes the ions in descending order of peak intensity or in descending order of mass numbers, and sends the mass number data to the MC creation unit (8) in descending order of priority. a display priority determining section (14); and the specifying means (1).
In accordance with the specification of the peak position in step 2), one mass spectrum data corresponding to the peak position is read out from the mass spectrum data storage section (4) and sent to the MC display priority determination section (14), and the MC MC every time mass number data is sent from the display priority determination unit (14).
A chromatograph/mass spectrometer comprising: a control section (16) that gives a mass spectrum creation command to a creation section (8).