JPS6182653A - Quadrupole mass spectrometer - Google Patents

Abstract

PURPOSE:To adjust incident conditions of ions into a main electrode by forming the captioned quadrupole mass spectrometer while providing an auxiliary quadrupole electrode fixed on the same axis as that of a main quadrupole electrode at a prescribed angle of rotation with respect to said main electrode. CONSTITUTION:A quadrupole mass spectrometer is constructed by arranging an ion source on the side A of a main quadrupole electrode 2 and a detector on the side B, while an auxiliary quadrupole electrode 4 is disposed between the ion source and the main electrode 2 adjoining to the main electrode 2 on the same axis as that thereof so as not to make contact therewith. Prescribed voltage is applied to both the electrodes 2,4 to permitions to enter there between for measurement, while the auxiliary electrode 4 is rotated by an angle theta and then fixed for analysis at a position of improved sensitivity and resolution of the spectrometer to the utmost. Thus, incident conditions of the ions onto the main electrode 2 can be adjusted, and furthermore even with an analyzer having accuracy of processing and assembly achievable with ease, disturbance of an electric field can be corrected to assure sufficient high sensitivity.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a quadrupole mass spectrometer used for qualitative analysis and quantitative analysis.

(Prior Art) A quadrupole mass spectrometer consists of an ion source, a quadruple Vi electrode set, and a detector. , only ions with a specific m/z (ratio of mass number to charge number) draw stable orbits. The ions that pass through the field reach the detector, while the ions with other m/z cannot reach the detector, so that ions are sorted by mass. Therefore, quadruple pi? l! If the machining accuracy or assembly accuracy of the pole is poor, sensitivity and resolution will decrease, especially in the high mass range.

In conventional quadrupole mass spectrometers, m/z = 1
1 to 3 μm to detect 000 with sufficient sensitivity and resolution.
A certain degree of machining and assembly precision is required.

(Problems to be solved by the invention) In order to achieve an accuracy of about 1 to 3 μm, there is a problem that not only extremely advanced processing technology and measuring instruments are required, but also that 1 small stop becomes worse6. The present invention provides a quadrupole I that can achieve high sensitivity and high resolution even with quadrupole electrodes that are processed and assembled with easily achievable precision.
The object of the present invention is to provide an R amount analyzer.

(Means for Solving the Problems) In the quadrupole mass spectrometer of the present invention, the quadrupole electrode is located between the main quadrupole electrode (hereinafter referred to as the main electrode) and the main electrode and the ion source. , and is provided with an auxiliary quadrupole electrode (hereinafter referred to as an auxiliary electrode) that is coaxially fixed with the main electrode and at a predetermined rotation angle with respect to the main electrode.

(effect) The ions leave the ion source and enter the main electrode.

After the incident position and angle of incidence on the main electrode are adjusted by the auxiliary electrode, the main electrode is sorted by a hyperboloid electric field similar to a conventional quadrupole electrode.

The auxiliary electrode reduces the effects of disturbances in the electric field caused by imperfections in the main electrode by adjusting the conditions for the incidence of ions into the main electrode.

(Example) FIG. 1 depicts a quadrupole electrode in one embodiment.

2 is a main electrode, 4 is an auxiliary electrode, an ion source (not shown) is located on the A side, and a detector (not shown) is located on the B side.

The main electrode 2 and the auxiliary electrode 4 are quadrupole electrodes having the same cross-sectional shape, and the processing and assembly accuracy of each is about 1 μm. The auxiliary electrode 4 is shorter than the main electrode 2. (For example, Lord?I
! Pole 2 is 200 mm and auxiliary electrode 4 is 50 mm. )
The main electrode 2 and the auxiliary electrode 4 are coaxially arranged as close as possible without contacting each other, and the same voltage, which is a combination of direct current and high-frequency alternating current, is applied to both electrodes 2 and 4.

The relative rotation angle e between the main electrode 2 and the auxiliary electrode 4 is
．． While performing measurements by applying a predetermined voltage to the auxiliary pole 4 and injecting ions, the auxiliary pole 4 is rotated and fixed at a position where sensitivity and resolution are most improved.

FIG. 2 shows a spectrum of PFTBA (perfluorotributylamine) near m/z = 502 using a conventional quadrupole mass spectrometer with an electrode processing and assembly accuracy of about 10 μm. On the other hand, Fig. 3 shows the same condition when adjusted to the optimum state in a quadrupole quality analysis device according to an embodiment of the present invention, which is equipped with an auxiliary electrode, although the processing and assembly accuracy of the electrodes is also approximately 10 μm. This is a spectrum near m/z=502 due to the sample. In conventional equipment m/z =
While the peaks of 502 and 503 are not separated,
It can be seen that in this example, the peaks at m/z=502 and 503 are separated by a sufficient amount, and both sensitivity and resolution are improved.

In the embodiment, the same voltage is applied to the main electrode 2 and the auxiliary electrode 4, but the voltage applied to the auxiliary electrode 4 may be different from the voltage applied to the main electrode 2. In that case, the condition for ion incidence into the main electrode 2 is the rotation angle e of the auxiliary electrode 4.
It becomes possible to adjust both the voltage and the applied voltage, increasing the degree of freedom in adjustment. Ion source type 1
For example, electron impact ion source, chemical ionization ion source.

FD (Field Desorbt, 1on) type ion source, FAB (Fast, At, oIIIBo
mbardment, ) type ion source, SIMS (Sec.
ondary Ion Mass 5pect, rom
The conditions for ion injection into the main electrode will vary depending on the type of ion source (et, ry) type ion source, etc., or depending on the case of negative ions, but even in such cases, both the rotation angle θ of the auxiliary electrode and the applied voltage must be adjusted. This makes it easy to obtain optimal ion injection conditions.

(Effects of the Invention) According to the present invention, sufficient sensitivity and resolution can be achieved even in a quadruple t@mass spectrometer configured with relatively easily achieved processing and assembly precision, such as about 10 μm, for example. I can do it.

The production of quadrupole electrodes does not require advanced processing technology or measuring equipment, and the production cost can be lowered because the small stop is improved.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a quadrupole electrode in one embodiment, and FIGS. 2 and 3 are diagrams showing spectra in a conventional device and a device in an embodiment of the present invention, which were manufactured with the same degree of precision, respectively. It is. 2...Main electrode, 4...Auxiliary electrode.

Claims (1)

[Claims] (1) In a device comprising an ion source, a quadrupole electrode, and a detector, the quadrupole electrode is provided between a main quadrupole electrode and the ion source, and the quadrupole electrode is provided between the main quadrupole electrode and the ion source. A quadrupole mass spectrometer comprising a main quadrupole electrode and an auxiliary quadrupole electrode coaxially fixed at a predetermined rotation angle with respect to the main quadrupole electrode.