JPS6059648A - Mass spectrometer - Google Patents

Abstract

PURPOSE:To enable ions of low mass ranges to be analyzed without using any complicate circuits by placing an electromagnet in the back of a tetrode electrode and separating ions of low mass ranges according to mass by performing field scanning of said electromagnet. CONSTITUTION:In detecting ions of low mass ranges such as hydrogen ion and helium ion, a given electric field permitting all ions to pass is applied to a tetrode electrode 4 by means of a controlling part 8. The voltage applied to the deflection electrode 6 is also controlled by the controlling part 8 in such a manner as to deflect ions toward an electromagnet 10. As a result, ions focused by an ion-focusing electrode 3b after being led out from an ion source 2 by means of an ion-leading-out electrode 3a, pass through the tetrode electrode 4 before being introduced toward the electromagnet 10 by means of the deflecting electrode 6. Ions passing through an incidence slit 12, enter the electromagnet 10. At this point, the current of the electromagnet 10 is controlled by the controlling part 8 to achieve field scanning thereby causing ions of low mass ranges to be separated according to mass. Separated ions, after passing through a collector slit 14, are detected with a low mass range detector.

Description

[Detailed description of the invention] (b) Industrial application fields The present invention relates to a mass spectrometer that analyzes the mass of ions.

(b) Prior art In general, the mainstream mass spectrometers are magnetic field type and quadruple type mass spectrometers, but the latter quadruple type mass spectrometer in particular has a simple structure, is small and lightweight; It is widely adopted due to its excellent high-speed scanning performance.

By the way, if you want to perform mass spectrometry on ions in the low mass range such as hydrogen ions, the conventional quadruple rectangular mass spectrometer requires a stable circuit that can scan from the low mass range to the high mass range. There is a problem in that the circuit structure is complicated with many parts, and the device itself becomes expensive.

(C) Purpose The present invention has been made in view of the above-mentioned problems, and
The object of the present invention is to obtain a mass spectrometer equipped with a quadrupole electrode that can perform mass analysis even on ions in a low mass range without requiring a particularly complicated circuit configuration compared to conventional ones.

In order to achieve this object, the present invention disposes an electromagnet behind the quadrupole electrode, and uses the magnetic field scanning of this electromagnet to mass-separate the ions in the low mass range guided by the electromagnet.

(E) Example Hereinafter, the present invention will be explained in detail based on an example shown in the drawings.

The figure is a diagram showing the structure of the mass spectrometer in this example.

In the figure, 1 is a mass spectrometer, 2 is an ion source section that generates ions, 3a is an ion extraction electrode that extracts ions generated in the ion source section, and 3b is a focusing electrode for ion focusing. 4 is a quadrupole electrode, a deflection electrode for deflecting ions that have passed through the 6-quadrupole electrode 4, 8I-1, voltage scanning of the quadrupole electrode 4, voltage setting of the deflection electrode 6, and the following. This is a control unit that controls magnetic field scanning of the electromagnet 10 and the like.

Behind the quadrupole electrode 4 is a small sector-shaped electromagnet 1.
0 is placed. This electromagnet 10 now has a magnetic field strength of Ho (Gauss) and an ion orbit radius in the magnetic field of a (
cm), and the ion mass number to be mass separated is M(a, m, u
), Ho・a when the ion acceleration voltage is V (volt)
It is configured to satisfy the relationship ==143.9.5 completed W. Note that 12 is an entrance slit provided in front of the electromagnet;
4 is the collector slit, 16 is the high mass region side detector, 1B
is the low mass region side detector.

Therefore, mass spectrometry of ions is carried out as follows using the mass spectrometer 41 having the following structure acid.

When detecting ions in a low mass range such as mass, hydrogen ions, helium ions, etc., the quadrupole electrode 4 is equipped with a control unit 8.
This applies a constant electric field that allows all ions to pass through. ! ! Further, the voltage applied to the deflection electrode 6 is controlled by the control unit 8 so that the ions are deflected toward the electromagnet 10 side. As a result, ions extracted from the ion source section 2 by the ion extraction electrode 3a and focused by the ion focusing electrode 3b pass through the quadrupole electrode 4 and are guided toward the electromagnet 10 by the deflection electrode 6. Ions passing through the entrance slit 12 enter the electromagnet 10. At this time, the electric current of the electromagnet 10 is controlled by the control unit 8, whereby magnetic field scanning is performed and ions in a low mass region are mass separated.

The mass-separated ions pass through the collector slit 14 and are detected by the low mass region side detector. For example, mass number 10a
For ions of K and U, from the above equation, V = 10 volts, a = 2.2'75 (z(, then H8 = +
It is analyzed with a magnetic field of 632.5 Gauss. At this time, the value of the current flowing through the electromagnet 10 is used as the mass marker, and the mass number is calculated from this value.

On the other hand, when ions in a high mass region are to be detected, the voltage applied to the quadrupole electrode 4 is scanned by the control unit 8, and the ions extracted from the ion source 2 are mass-separated by the quadrupole electrode 4 itself. The mass-separated ions are guided to the high-mass region side detector 16 by the deflection electrode 6 and detected.

(f) Effect As described above, according to the present invention, an electromagnet is placed behind the quadrupole electrode, and ions in the low mass region are mass-separated by scanning the magnetic field of this electromagnet, so a complex circuit is constructed. It becomes possible to analyze ions in the low mass range without having to Moreover, since the electromagnet can also be small, it has the advantage of being relatively inexpensive.

[Brief explanation of drawings]

The figure is a configuration diagram of a mass spectrometer showing one embodiment of the present invention. 1. Mass spectrometer, 4. Quadrupole electrode, 10. Electromagnet. Applicant: Shimadzu Corporation Agent: Kazuhide Okada, Patent Attorney

Claims (1)

[Claims] (1) A mass spectrometer comprising a quadrupole electrode, an electromagnet placed behind the quadrupole electrode, and mass-separating ions in a low mass range guided by the electromagnet by scanning the electromagnet's magnetic field. .