JPS6050301B2 - chromatograph mass spectrometer - Google Patents

Description

[Detailed Description of the Invention] When using a data processing device in a gas chromatograph mass spectrometer, the conventional method for calibrating the mass axis is an interaction between the data processing device and an analysis operator (a human inputs the direct mass number). -, -fJ°' (-L to ↓,
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The present invention aims to provide a chromatograph mass spectrometer capable of automatically calibrating the mass axis.

Examples will be described below. FIG. 1 shows an embodiment of the chromatograph mass spectrometer of the present invention, in which 1 is a gas chromatograph, 2 is a monocular separator for concentrating the gas flowing out from the gas chromatograph, and 3 is for concentrating the gas flow from this separator. A normal slide valve is used to arbitrarily turn on or off. 4 is an automatic valve control device for controlling the valve 3; 5 is a heated sample introduction slide valve (hereinafter referred to as Hi valve) for introducing a heated standard sample (SH); 6 is a heated sample introduction device; 7 is a data processing device.

8 is an ion source, 9 is an analysis tube, 10 is a magnet, 101 is a magnetic field strength (mass axis signal) detection section in the analysis tube, 11 is an ion detector that detects the intensity of ions dispersed in the analysis tube, 12
is a measurement result display and recording device (for example, a bidy graph), and the magnetic field strength signal from the magnetic field strength detection unit 101 (
The mass axis signal) and the ion intensity signal from the detector 11 are input to a data processing device 7 and a display/recording device 12, respectively.

The data processing device is equipped with all normal data processing functions, and the signals from the magnetic field strength detection section 101 and the detector 11 are A
It is input via a D converter 71.

72 is a valve control software section that stores a program for valve control, 73 is a mass axis automatic calibration software section that stores a program for automatically calibrating the mass axis, and 74 is an automatic valve that controls the operations of the Hi valve 5 and other operations. This is a valve control signal section that operates the control device 4.

The contents of these programs are shown in FIG. 2, and will be explained below together with the operation of the apparatus shown in FIG. 1. First, during normal measurement, valve 3 is open and valve 5 is closed. Analysis sample is gas chromatograph 1
The sample is introduced into a sample introduction device, separated into components and eluted, and most of the carrier gas is removed by the separator 2, thereby concentrating the sample components. The slide valve 3 is closed while the peak of the solvent component of the sample is flowing out, and is open while the peak of the desired sample component is flowing out. The sample sampled by the slide valve 3 is ionized in the ion source 8, dispersed through the analysis tube 9, and detected for each mass number by the detector 11 according to mass number scanning (magnetic field scanning).

On the other hand, the mass axis signal is detected by the detection unit 101. This mass axis signal is converted into a mass number using a conversion formula stored in the data processing section, and sent together with the ion intensity signal to the display/recording device 12, where a mass spectrum is drawn.

2. For a predetermined period of time after the start of measurement, for example, chromatography. When the flow reaches the middle of the outflow peak and the peak, mass axis automatic calibration starts and the slide valve 3 is sent to the automatic valve control unit 4 via the valve control signal unit 74 according to the valve control software.
A signal is sent to close the Hi valve 5 and open the Hi valve 5, the slide valve 3 is closed, and then the Hi valve 5 is opened, and the standard sample SH is introduced into the mass spectrometer via the heated sample introduction device 6 and the slide valve 5. be done.

Next, a scanning signal is sent to the magnet device 10 to perform magnetic field scanning, and the data processing device 7 reads the mass axis signal related to the ion intensity signal of a predetermined spectral peak of the quasi-sample being measured at this time, and stores it in memory. The mass number converted using the conversion formula is compared with the mass number of the standard sample, which is also stored, and a deviation value is calculated. For example, about 20 to 30 representative points for comparison may be taken at 10-square intervals in terms of mass numbers.

Next, conversion is performed so that this deviation value is minimized, and a new conversion formula is obtained by least squares approximation using a cubic curve, for example. This conversion formula is calculated from the previous calibration in which this formula was stored. is stored in place of the expression.

When the above processing is completed, a signal to open the Hi valve 5 is sent to the automatic valve control unit 4 via the valve control signal 7) 4, and then a signal to open the slide valve 3 is sent to 4 via the valve control signal 74. 3 is opened to return to the measurement start state, and the mass number of the sample introduced from the chromatograph is calculated from its mass axis signal based on the newly stored conversion formula. become.

Thereafter, such a process of calibration, measurement, one axis, and so on is automatically repeated.

Note that when performing the first calibration before measurement, there is no previous conversion formula to be compared, but in this case, an appropriate conversion formula may be used.According to the present invention, as described above, the mass calibration axis movement This can be done automatically and the troublesome manual mass axis calibration operation can be omitted, and the following effects can also be obtained.

In a gas chromatograph mass spectrometer, if the device is used for a long time, the mass axis signal will drift due to various factors (e.g. temperature rise), so it is important to quickly calibrate the signal during analysis without interrupting the analysis for a long time. However, in the present invention, calibration is automatically and quickly performed according to a predetermined program, for example, between peaks from a chromatograph, so drift of the mass axis signal is almost eliminated, and the data processing device 7 The analysis accuracy, data reliability, and reproducibility of the output data from the system are significantly improved.

FIG. 3 shows another embodiment of the present invention, which has all the configurations shown in FIG. 2.

Common symbols indicate common elements, but some are omitted in the figure. In Fig. 3, 51 is a valve for direct sample introduction;
Reference numeral 1 denotes a direct sample introduction device, and a signal is given to the valve automatic control device 4 via the valve control signal section by the valve control software 72, thereby controlling each valve 3, 5.
, 51 are controlled.

Further, in FIG. 3, in addition to a valve opening/closing command signal transmission system 41 from the valve control signal section 74 to the valve automatic control device 4, a valve status reading signal transmission system 42 from the valve automatic control device 4 to the valve control signal section 74 is shown. is provided, making the sample introduction operation extremely simple. That is, in the conventional apparatus, even if it is desired to introduce a standard sample etc. from the Hi valve 5, the Hi valve 5 is closed when the sample to be analyzed is being sent to the analyzer from another sample introduction device 1 or 61. Therefore, it was not possible to introduce a sample from the heated sample introduction device.

In the apparatus shown in FIG. 3, for example, when a command to open the Hj valve 5 is issued from the valve control signal section 74 according to the judgment logic (FIG. 2) of the valve control software shown in FIG. Control is performed to change the slide valve 3 from open to closed, and then control to change the Hi valve 5 from closed to open is performed.

The automatic valve control device 4 sends a status reading signal for each valve to the data processing device 7, which determines that preparation for analysis is complete and sends a signal to start analysis to the GCMS control device 91.

A sample (normally a standard sample) introduced from a heating sample introduction device 6 or the like is ionized by an ion source 8, passes through an analysis tube 9, is detected by a detector 11, and the measurement results are recorded in a Visigraph 12, as well as being calibrated as described above. will be carried out.

(Note that in this figure, the connections shown in Figure 1 that take in the mass axis signal to the data processing device are omitted.) When the analysis using the heated sample introduction device is completed, the Hi valve 5 is opened and then closed, and the slide valve 3 is closed. → Opening control is performed based on a command from the data processing device 7, and the valve returns to its original analysis state and the analysis continues.

As described above, in this invention, calibration can be quickly performed in a chromatograph mass spectrometer according to a predetermined program during the intervals between the appearance of peaks of separated components from the chromatograph, thereby increasing the reliability of analysis results. It can be particularly effective for trace analysis.

Note that although this application uses the opening and closing of a slide valve, the slide valve can be opened and closed in a short period of time due to its function, and is particularly useful when software of a data processing device is used as in the present application. It is.

[Brief explanation of the drawing]

1 and 3 are schematic diagrams of an apparatus according to an embodiment of the present invention, and FIG. 2 is a diagram showing an example of a pronogram used in the apparatus of the present invention. 1... Gas chromatograph, 2... Separator, 3... Slide valve, 4...
... Automatic valve control device, 5 ... Valve for heating sample introduction, 6 ... Heating sample introduction device, 7 ...
...data processing device, 8...7 ion source, 9...
...Analysis tube, 10... Magnet device, 11...
...Ion detector, 12...Display and recording device, 7
1... AD converter, 72... Valve control software section, 73... Mass axis automatic calibration software section, 74... Valve control signal section.

Claims (1)

[Claims] 1. A first slide valve installed in the flow path between the chromatograph and the mass spectrometer to introduce components flowing out from the chromatograph, and a standard sample introduced directly into the flow path without going through the chromatograph. and a second slide valve provided in the side passage, wherein the first slide valve and the second slide valve are periodically opened and closed according to a predetermined program. and a data processing device that alternately opens and closes the first and second valves via the valve control device, and the data processing device controls the control of a predetermined value of the standard sample introduced when the second valve is open. The mass number converted from the mass axis signal related to the ion intensity signal of the spectral peak is compared with the mass number of the standard sample, and a conversion formula for calibrating the mass axis signal according to the deviation value is calculated. A chromatograph mass spectrometer characterized in that a mass axis signal of a sample is calculated based on a conversion formula.