JPS60207050A - Mass fragmentgraphic apparatus - Google Patents

Abstract

PURPOSE:To perform the calculation of resolving power and millimass, by introducing an analytical specimen of reference mass at the time of positional alignment of the mass spectrum peak in a mass fragmentgraphy. CONSTITUTION:A reference specimen is introduced into a mass spectrumeter M and the data of the profile of the mass spectrum peak of the reference specimen is obtained. The intensity of a magnetic field corresponding to the center of the mass spectrum peak of the reference specimen is detected from said data and the setting thereof is performed so that the reference mass spectrum peak is coincided with an ion emitting slit and resolving power in the good state (vacuum state) of the mass spectrumeter M is calculated from the profile data. Next, the gaseous mixture of a measuring specimen and the reference specimen is introduced into the mass spectrometer M and the magnetic field is fixed to perform accelerated voltage scanning. Then, ion acceleration voltage is stepwise changed in alignment with the mass of an ion to be detected to perform mass scanning. In this scanning, the data of the mass spectrum of each ion is stored in memory and millimass and resolving power at the introduction time of the specimen is calculated by using this data.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a chromatograph mass spectrometer suitable for performing mass fragmentography.

・Conventional technology When sample molecules are ionized, they split to form various fragment ions.The sample components flowing out of the chromatograph are introduced into a mass spectrometer, and several fragment ions are selected and detected. By recording the temporal increase and decrease of fragment ions, various information can be obtained regarding the sample components separated by chromatography, and peaks of sample components that are insufficiently separated by chromatography can be separated. Mass fragmentography selects and detects several fragment ions in this way and records their increase or decrease.The operation of a mass spectrometer is to adjust the ion acceleration voltage stepwise according to the mass of the ions to be detected. By switching to , mass scanning is repeated at a relatively high speed and the detected intensity of each ion is recorded.

However, the resolution of a mass spectrometer is different when only a pure sample is introduced and mass spectrometry is performed in a high vacuum state, and when it is connected to a chromatograph and a mixed gas of sample components and carrier gas is introduced. The degree of vacuum is somewhat reduced, as in the case of Therefore, when performing mass fragmentography, one would like to know the resolution in that case, but in the past, only the resolution in a good state was measured using a standard sample, and the resolution was not measured during actual operation.

Eighth target.

An object of the present invention is to enable resolution measurement during one actual operation when performing mass fragmentography.

2. When performing constituent mass fragmentography, the mass spectral peaks must be aligned so that the position of each selected ion's mass spectral peak correctly matches the ion exit slit position of the mass spectrometer. , and then the actual mass fragmentography operation begins. The present invention attempts to measure the separation power of a mass spectrometer during mass fragment graphing by utilizing this mass peak positioning operation.

E. Embodiment FIG. 1 is a flowchart of the operation of the apparatus of the present invention. When the operation starts, a standard sample is first introduced into the mass spectrometer (2), and a magnetic field scan is performed with the acceleration voltage constant (2).
mouth). The magnetic field strength data and ion detection strength data are memorized (c) by the operation in step (b). The data obtained here is the mass spectrum peak profile data of the standard sample.

Next, from this data, the magnetic field strength corresponding to the center of the mass spectrum peak of the standard sample is detected, and the magnetic field strength is set so that the spectrum peak of the reference mass coincides with the ion exit slit (d). Calculate the resolution of the mass spectrometer under good conditions from the data and print it out using a printer.

Display (e), then introduce the measurement sample, that is, a mixed gas of chromatograph outflow gas and standard sample, into the mass spectrometer, fix the magnetic field, and perform accelerating voltage scanning (g). The accelerating voltage scanning device in ＼ is a device that changes the ion accelerating voltage as shown in FIG. 2A.

When performing mass fragmentography, mass scanning is performed by changing the ion acceleration voltage in steps according to the mass of the ion to be detected, as shown in Figure 2B. In order to determine the voltage at each step so that the center correctly matches the center of the ion exit slit, this step-like voltage is superimposed with a sawtooth wave voltage to form the accelerating voltage scanning device. In this scan, the mass spectrum data of each ion is stored in memory (
Using this data, calculate the millimas and display it on a printer, etc.), and also calculate the resolution at the time of sample introduction and display it. After that, the original mass fragmentography begins. As shown in FIG. 3, the millimas measurement can be carried out as follows, since the accelerating voltage scanner sweeps the accelerating voltage approximately centered on the spectral peak of the target fragment ion. Since peaks b and bl of standard sample ions with known masses appear on both sides of spectral peak a of the target ion, peak b can be calculated from the interval ΔM between the two peaks with known masses and the peak position X of the target ion. Let the mass of the present ion be Ml, and the exact mass M of the target ion be ``φ-,, Ml + X/Δ
y) by M.

FIG. 4 shows the configuration of an apparatus according to an embodiment of the present invention.

G is a gas chromatograph, M is a mass spectrometer, and F is an interface that connects the two, consisting of a standard gas introduction pulp, a molecular separator that removes a carrier gas from the gas flowing out of the gas chromatograph, and the like. S is a standard sample reservoir, and D is an ion detector of the mass spectrometer M. C executes the operation flow shown in FIG. 1 on a computer. K is an ion accelerating voltage generating circuit which is controlled by computer C and generates ion accelerating voltages as shown in FIGS. 2A and 2B. m is a memory that stores measurement data, and P is a display device.

Effects According to the present invention, analysis information such as resolution and millimeter can be obtained simultaneously by using alignment of mass spectrum peaks in mass fragmentography, and analysis information is increased compared to conventional mass fragmentography. Improves reliability of analysis results0

[Brief explanation of the drawing]

FIG. 1 is a flowchart of the operation of an apparatus according to an embodiment of the present invention, FIG. 2 is a graph of ion acceleration voltage in acceleration voltage scanning, FIG. 3 is an explanatory diagram of millimus measurement method, and FIG. 4 is the configuration of the above embodiment. FIG. G...Gas chromatograph, F...Interface, M...Mass spectrometer, K...Ion accelerating voltage generation circuit. Agent Patent Attorney Hiroshi Kaiya Figure 4

Claims (1)

[Claims] Equipped with a standard sample automatic introduction means, a standard sample is introduced to set the magnetic field for the reference mass, and then an analysis sample of the standard mass is simultaneously introduced, and each step is made to perform discrete changes using the ion accelerating voltage that changes incline. A mass fragmentography device that performs mass scanning, stores mass spectrum data of each fragment ion and standard sample ion, and calculates and displays resolution and millimeter based on the data.