RU214177U1 - QUADRUPOLE MASS FILTER BASED ON A UNIVERSAL HYPERBOLIC ELECTRODE - Google Patents

Abstract

The utility model relates to the field of mass spectrometry and can be used to create a quadrupole mass filter. To construct the electrode system of the quadrupole mass filter, it is proposed to use four universal hyperbolic electrodes separated by flat ceramic insulators. Also, the proposed design of the quadrupole mass analyzer makes it possible to implement the sectional principle of constructing extended electrode systems based on interconnected quadrupole cells.

EFFECT: use of identical electrodes, as well as ceramic insulators in the form of rectangular parallelepipeds, the manufacturing error of which is no worse than 1 μm, makes it possible to increase the accuracy of the entire electrode system and simplify its assembly. 3 ill.

Description

The utility model relates to mass spectrometry, in particular to transit-type dynamic mass spectrometers, and can be used to create a quadrupole mass filter with improved operational and analytical characteristics [1].

Traditionally, as field-forming electrodes of a quadrupole mass filter, rods of circular cross section were used, located parallel to each other, creating a quadrupole electric field. In this case, the device for fixing the electrodes of the quadrupole analyzer is an insulated holder, on the inner surface of which cylindrical electrodes are fixed [2-4].

Known methods for constructing quadrupole electrode systems, in which rods of circular cross section were replaced by hyperbolic electrodes [5]. In this case, the electric field in the working volume of the analyzer is more close to a linear (quadratic potential distribution), and as a result, it makes it possible to improve the analytical characteristics of the analyzer. The disadvantages of this design, which provides the exact position of the field-setting electrodes relative to the surfaces lying outside the working volume, is the difficulty of accurately fixing the distance from the rods to the center of the system, which leads to distortion of the electric field in the working volume of the analyzer.

There is a known method for manufacturing a quadrupole mass filter sensor [6], according to which a metal layer is applied to a metal mold, the outer surfaces of which repeat the inner surfaces of the analyzer, with insulators fixed on it. After that, this layer is removed at the junctions of various electrodes, after which the mold is removed and a monoblock design of a quadrupole mass filter is obtained, the location of the electrodes in which repeats the position of the working surfaces of the mold. The disadvantage of such a device of the mass analyzer is the non-separable design, which complicates the operation of the device and the complexity of the precise manufacture of an extended form and an electrode system, respectively.

In the well-known quadrupole mass filter sensor [7], an increase in the accuracy of an extended electrode system is achieved through the use of a large number of identical sections, each of which contains four field-forming electrodes bonded to each other and isolated from each other, while the cascades are mechanically connected to each other, providing electrical contact between the respective electrodes and obtaining a single extended electrode system of the quadrupole mass filter.

The purpose of the proposed utility model is to improve the analytical and operational characteristics of quadrupole mass analyzers through the use of a collapsible electrode system with hyperbolic electrodes that does not require additional alignment during assembly.

To build the electrode system of the quadrupole mass filter, four identical hyperbolic electrodes are used, the appearance of which is shown in Fig. one.

Each electrode has a working hyperbolic surface 1 and end areas 2, made in the form of a plane parallel to the asymptote of the hyperbola and recessed into the electrode. The size of the recess in the end area corresponds to the size of ceramic insulators in the form of rectangular parallelepipeds and provides the necessary mutual arrangement of the electrodes in the system without additional adjustment. The electrodes are connected to each other through the holes 3, made in the end areas, using bolted connections and ceramic bushings.

Fig. 2 depicts a diagram of the bolted connection of two electrodes to each other (1 - electrode, 4 - ceramic insulator in the form of a rectangular parallelepiped, 5 - bolt, 6 - washer, 7 - ceramic bushing, 8 - nut). This provides both the necessary electrical insulation of the electrodes and their required relative position relative to each other due to the use of a ceramic insulator in the form of a rectangular parallelepiped made with high precision.

Fig. 3 depicts the principle of constructing a quadrupole mass filter based on four identical hyperbolic electrodes (1 - hyperbolic electrode, 4 - ceramic insulator in the form of a rectangular parallelepiped, 9 - hole for connecting electrodes of adjacent sections, 10 - asymptote of the hyperbolic surface of the electrode).

Such a device of a quadrupole mass analyzer makes it possible to increase the accuracy of the entire electrode system and simplify its assembly due to:

using identical electroformed electrodes using a single precision mold;

the use of ceramic insulators in the form of rectangular parallelepipeds for connecting electrodes to each other, the manufacturing error of which, due to their simple shape, is no worse than 1 micron.

The proposed design of the quadrupole mass analyzer also makes it possible to implement the well-known [7] sectional principle of constructing extended electrode systems and to produce a unified series of devices, when their length and analytical parameters are determined by the number of corresponding quadrupole cells. At the same time, sections of the electrode systems are mechanically interconnected through holes for connecting the electrodes, providing electrical contact between the corresponding electrodes and obtaining a single extended electrode system of a quadrupole mass filter, and ceramic insulators in the form of rectangular parallelepipeds provide not only automatic adjustment of the electrodes relative to each other, but and individual sections.

Literature

1. G.I. Slobodenyuk. Quadrupole mass spectrometers. M., Atomizdat, 1974.

2. A.S. 285322 USSR.

3. A.S. 469479 USSR.

4. A.S. 868885 USSR.

5. A.S. 868886 USSR.

6. Patent 2091902 RF.

7. Patent for utility model 156466 RF.

Claims (1)

The design of the electrode system of a quadrupole mass filter, consisting of four electrodes of a hyperbolic profile, characterized in that each electrode has a working surface and end areas made in the form of a plane parallel to the asymptote of the hyperbola and recessed into the electrode in such a way that the size of the end area recess corresponds to the size of the ceramic insulators in the form of rectangular parallelepipeds and provides the necessary mutual arrangement of the electrodes when assembling the system using bolted connections and ceramic bushings through the holes in the end areas without additional adjustment.

Images