JPH0658343B2 - Recording method of measured spectrum of double-focusing mass spectrometer - Google Patents

Description

Detailed Description of the Invention a. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recording a measurement spectrum in a double focusing mass spectrometer.

Normally, in a double-focusing mass spectrometer in which an ion source, an electric field, a magnetic field, and a detector (forward arrangement) or an ion source, a magnetic field, an electric field, and a detector (reverse arrangement) are arranged in this order, the electric field is accelerated by the ions. Fixed to a constant value according to the voltage and scanning the magnetic field,
That is, besides the measurement of the mass spectrum of the ionized sample molecule ions using the magnetic field as a scale, the cleavage reaction of the ions can be investigated.

Of the ions generated by the ionization of the sample molecules, the ions are metastable and decay naturally, or are activated by collision with an appropriate molecule introduced from the outside, and are further cleaved into neutral molecules and ions. In the ion cleavage reaction, the original ion before the cleavage is called the parent ion and the ion generated by the cleavage is called the daughter ion, and the specific mass of what kind of daughter ion a certain mass of parent ion produces The mass spectra of all the daughter ions generated from the parent ions of are the mass spectra of the sample molecule ions measured by scanning the magnetic field with the electric field fixed at a constant value according to the ion acceleration voltage, and important information for the analysis of the sample. give.

The present invention relates to the above-mentioned method for recording both mass spectra.

B. 2. Description of the Related Art When an ion (parent ion) accelerated to a predetermined energy by an ion accelerating voltage from an ion source is decomposed (split) into several daughter ions before entering an electric field, all of the ions generated from a parent ion having a specific mass M The mass spectrum of the daughter ions of the above is to be measured by the so-called linked scanning method (B / E method) in which the electric field and the magnetic field are scanned using a double-focusing mass spectrometer while keeping the ratio of the electric field and the magnetic field constant. You can

In the double focusing mass spectrometer, the ion acceleration voltage is Va
If c is the magnetic field and B is the magnetic field, the mass M of an ordinary ion passing through the magnetic field is C In ordinary mass spectrometry, the electric field Eo is used as the kinetic energy eVa.
It is set so that ions having c (e is the charge of the electron) pass through. Since the parent ion and the daughter ion have the same velocity in the ion cleavage reaction, if the mass of the parent ion is M, the daughter ion mass is m, and the velocity at the ion acceleration voltage Vac is v, the kinetic energy of the parent ion is Ko is The kinetic energy K of the daughter ion is Therefore Consider the case of measuring a mass spectrum of a daughter ion generated from a parent ion of mass M. The kinetic energy when a daughter ion of mass m is incident on the magnetic field is given by the above equation (2), and the acceleration voltage of the ion of mass m is (m / M) Va
Since it is equivalent to c, the magnetic field B'can be calculated by the above equation (1) in order for this ion to pass through the magnetic field. Also, in order for these ions to pass through the electric field, the electric field E corresponds to the energy (m / M) eEo Equation (3) is transformed In Eqs. (4) and (5), E, Eo, and C are constants, and when M is set to a certain value, E = C'm, B '= C ″ m, and the ratio of E to B is kept constant. While scanning E and B, daughter ions m generated from parent ions of mass M can be scanned.

In the past, since the mass spectrum of the daughter ion obtained by the above-mentioned linked scanning method was recorded and displayed by itself, it was recorded separately to obtain comprehensive information about the sample. It is inconvenient to see it against the usual mass spectrum.

C. Problems to be Solved by the Invention An object of the present invention is to solve the inconvenience in practical use of the above-mentioned conventional display method of the measurement result in the double-convergence mass spectrometer.

D. Means for solving the problem The mass spectrum of the daughter ions was recorded alongside the normal mass spectrum recording.

E. Embodiment FIG. Shows an embodiment of the present invention. In this figure, the scale on the horizontal axis indicates mass, and the vertical axis indicates the detected intensity of ions. The upwardly extending spectral record on the lower horizontal axis shows the normal mass spectrum, and the downwardly extending spectral record from the upper horizontal line is the mass spectrum of the daughter ion. The above
B / E = B according to Eqs. (4) and (5)
And scan E and perform linked scanning, E
= Eo, Since the parent ion itself having a mass M is detected and all the daughter ions have smaller masses than M, the peak of the maximum mass in the mass spectrum of the daughter ion represents the parent ion, and in FIG. 1, M is this parent ion. If the positions of the mass scales are made to coincide in the recording of both spectra, the peaks of both spectra will be difficult to understand because they overlap, so in this example, the mass scale of the daughter ion spectrum recording is slightly shifted to the left to show the peaks of both spectra. So that they do not overlap.

The present invention is not limited to the graph display as described above,
It goes without saying that the numbers may be displayed on a table.

F. Effect According to the present invention, since two kinds of mass spectra for one sample are displayed side by side, the records of the two kinds of mass spectra can be organized easily, and the understanding of the spectrum structure is greatly facilitated.

BRIEF DESCRIPTION OF THE DRAWINGS The figure shows an example of a measurement result record according to the present invention.

Claims (1)

[Claims] 1. An ion source, an electric field or a magnetic field, a magnetic field or an electric field,
In a double-focusing mass spectrometer in which these are arranged in the order of detectors, the electric field and the magnetic field were scanned while keeping the ratio of the electric field to the magnetic field constant, and the ions were accelerated to a predetermined energy by an ion accelerating voltage. Before the ions enter the electric field, the spectra of all daughter ions generated from the parent ions of a specific mass that are decomposed and produced by the cleavage reaction are measured, and the electric field is fixed to a certain value according to the ion acceleration voltage and the magnetic field is fixed. A method for recording a measured spectrum of a double-convergence type mass spectrometer, characterized in that a mass spectrum is measured by scanning, and both of these spectra are arranged and recorded on the same mass scale.