JPS62168333A - Mass spectrometry - Google Patents

Abstract

PURPOSE:To enable the mass spectrometry of grandchild ions to be carried out with only one mass spectromeater, by utilizing a cleavage occurring in the first free space between an ion source and a mass spectrometry portion for measurement. CONSTITUTION:In case that the ion of a mass Mp is set to be detected, ion acceleration voltage is represented by V, a magnetic field intensity by Bp, and the electric field intensity of an energy spectrometry portion by Fp. Here, the mass of a parent ion is represented by the Mp, the mass of a daughter ion by Md, and the mass of a grandchild ion by Mg. When a magnetic field intensity Bd is set up according to the formula I, an electric field intensity Fd in case that the daughter ion of the mass Md is made to pass through an electric field E is described by the formula III. As the mass Mg of the grandchild ion is smaller than the Md, the energy spectrum of the grandchild ion appears on a position where the electric field intensity is lower than the Fd when the electric intensity is swept. And the electric field intensity Fg in case that the grandchild ion of the mass Mg is detected is given by the formula II. When a collision activating method is utilized for the cleavage of the daughter ion, a collision chamber CC is disposed on the position of the dotted line. In case of the parent ion, the collision chamber is disposed immediately after an inlet slit S in front of an ion source I, S.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a method for tracking ion cleavage reactions using a mass spectrometry technique.

When a sample is ionized using conventional mass spectrometry techniques, a wide variety of ions are generated, among which are metastable ions that spontaneously cleave into new ions and neutral molecules. Furthermore, when an appropriate molecule collides with an ion, the ion is cleaved by the impact and becomes a new ion and a neutral molecule. In an ion cleavage reaction like this, the ion before cleavage is called the parent ion, and the ion produced by the cleavage is called the daughter ion. By the way, some of these daughter ions are further cleaved and grandchild ions are generated.

Therefore, a series of ions are generated by dissociation from one type of ion, and useful information for organic analysis can be obtained by examining the family tree of such ions.

In order to conduct the above-mentioned investigation, first select an ion with a specific mass by mass spectrometry, then select another ion with a specific mass from the daughter ions generated by the cleavage of this ion, and perform the selection in this way. The mass spectrum of the grandchild ions produced by the cleavage of the daughter ions of a specific mass will be measured.

Therefore, conventional equipment for performing such analysis consists of one mass spectrometry section, a first energy analysis section following it, and a first energy analysis section.
This required the arrangement of three energy analysis sections, one followed by a third energy analysis section, and measurements could not be performed with a single double-focusing mass spectrometer.

C. Problems to be Solved by the Invention The present invention uses a single magnetic field leading double focusing mass spectrometer to
This is intended to enable mass spectrometry of the grandchild ions mentioned above.

2. Means for solving the problem Among the various daughter ions generated by the cleavage reaction between the ion source and the mass spectrometer (first free space), the daughter ion with mass Md generated from the parent ion with mass Mp is The magnetic field is set so that it can pass through the mass spectrometer, and the kinetic energy of the grandchild ion generated by the cleavage of the daughter ion is measured in the space between the mass spectrometer and the energy analyzer (second free space) in the energy analyzer. I started doing analysis.

E The ion cleavage reaction starts when the sample is ionized and proceeds at a constant reaction rate determined by the type of ion, so the cleavage reaction can occur at any position on the ion trajectory within the mass spectrometer. . Of these, the present invention utilizes the cleavage that occurs in the first free space between the ion source and the mass spectrometer for measurement. Since the speed of the ion does not change due to the cleavage reaction, the mass of the parent ion is Mp, the kinetic energy determined by the ion acceleration voltage is Ep, the mass of the daughter ion is Md, the kinetic energy is Ed, the mass of the grandchild ion is Mg, If the kinetic energy is Eg, then let Bp be the magnetic field strength that allows an ion of quality 11LMp to pass through the magnetic field at the ion acceleration voltage V.

The daughter ion Md generated in the first free space has less energy than the parent ion with mass Ml accelerated by the acceleration voltage V,
Its energy Ed is. In other words, the daughter ion Md has the same kinetic energy as the parent ion with mass Mf whose acceleration voltage is lowered to V'. Therefore, the magnetic field strength Bd for allowing such daughter ions to pass through the mass spectrometer is given by: Instead of determining the magnetic field strength according to the above formula, the magnetic field strength may be set to Bp, and the ion acceleration voltage may be set to Mp/Md times V. In this way, the mass spectrometer selects ions of quality ffiMd among the daughter ions generated from the parent ion of mass Mp in the first free space. The relationship between the kinetic energy and mass of the grandchild ions produced by this daughter ion cleavage in the second free space is as described above, so if the applied voltage of the energy analyzer is swept and the energy spectrum is measured, the energy and mass can be measured. It is proportional to the mass,
The energy spectrum represents the mass spectrum of the grandchild ion.

Example The figure shows an example of a device for carrying out the method of the invention.

Is is an ion source, B is a magnetic field for mass analysis, E is an electric field for energy analysis, and D is an ion detector, and the whole constitutes a magnetic field leading type double focus mass spectrometer.

In the figure, 1st and FFR are the 1st free space and 2ndF.
FR is the second free space. Ion cleavage reactions occur anywhere on the ion trajectory from the ion source to the detector, but the present invention deals with daughter ions generated by the cleavage of parent ions in the first free space up to the second free space. This is to select and detect grandchild ions produced by cleavage of the incoming daughter ions in the second free space.

Now, when the apparatus shown in FIG. 1 is used for normal mass spectrometry and is set to detect ions of mass Mp, the ion acceleration voltage is V, the magnetic field strength is Bp, and the electric field strength of the energy analysis section is Fp. Here, the mass of the parent ion is Mp, the mass of the daughter ion is Md, the mass of the grandchild ion is Mg, and the kinetic energies of each are El)t, Ed, and Eg, as described in the action section (1).

Equation (2) holds true. The magnetic field strength B(l
When the daughter ion with mass Md is set to pass through the electric field E, the electric field strength Fd is the grandchild ion's mass Mg is smaller than Md, so the energy spectrum of the grandchild ion is the electric field strength when the electric field strength is swept. appears below Fd. The electric field strength Fg when a grandchild ion of mass Mg is detected is given by:

Although the above explanation deals with the case where both the parent ion and the daughter ion are metastable ions and undergo spontaneous cleavage, it is also possible to use the collisional activation method in which the ion is bombarded with a neutral molecule to force a cleavage reaction. It goes without saying that the present invention is applicable. For example, when using the collisional activation method to cleave daughter ions, the collision chamber CC may be installed at the position indicated by the dotted line in the figure. The collision chamber is a box having ion passage holes at the front and rear, into which a collision gas such as He is introduced. When using the collisional activation method to cleave the parent ion, use the ion source ■ in the figure.

A collision chamber may be installed immediately after the entrance slit S in front of the S.

G. Effects According to the method of the present invention, it is possible to track the reaction in which one parent ion undergoes repeated cleavage with a single double-focusing mass spectrometer. Including spectrum measurement (MIKES measurement), three types of measurements are possible with one mass spectrometer.

[Brief explanation of drawings]

The drawing is a plan view of an apparatus according to an embodiment of the present invention.

Claims (1)

[Claims] Magnetic field strength Bp and electric field strength Fp of the energy analysis section when a parent ion with mass Mp is detected using a mass spectrometer in which a mass spectrometry section precedes and an energy analysis section follows.
In contrast, when the magnetic field Bd of the mass spectrometer is set as Bd=(Md/Mp)Bp Md<Mp and the electric field set in the energy analyzer is Fg, the mass Mg of the detected ion is Fg=(Mg /Mp)Fp.