JPH0334046Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to an ion source for a gas chromatograph mass spectrometer (GC-MS) used for qualitative and quantitative analysis of mixture samples.

(Prior art) A gas chromatograph mass spectrometer is a device that directly connects a gas chromatograph and a mass spectrometer.
In order to accommodate a wide range of application fields, a mass spectrometer is usually provided with at least three sample introduction systems. These sample introduction systems include, for example, as shown in Figure 2, a standard sample introduction system 2, a packed column introduction system 4 that is introduced from a packed column of a gas chromatograph via a separator or a splitter, and a capillary column of a gas chromatograph. This is the capillary column introduction system 6 introduced from.

Each of the sample introduction systems 2, 4, and 6 is attached to the vacuum chamber 12 of the mass spectrometer by a vacuum flange 10 formed integrally with the sample introduction system holder 8, and the sample gas is introduced into the ionization chamber 14 in the vacuum chamber 12. are being introduced. The path of each sample introduction system holder 8 and the ionization chamber 14 are connected by connectors 16, which can be expanded and contracted in the axial direction, and a force is applied in the direction of expansion by a spring 18. By making spherical contact between the sample introduction system path and the ionization chamber 14, the connection between the sample introduction system path and the ionization chamber 14 is kept airtight. Further, each sample introduction system holder 8 is provided with a temperature adjustment heater 20 for preventing the sample from adhering to the inner wall. In this example, the ionization chamber 14 is of an electron impact type and includes a filament 22 and a trap 24.

Generally, it is desirable that the sample introduction system into the ionization chamber 14 be straight. Therefore, in conventional gas chromatograph mass spectrometers, the sample introduction system is
As shown in the figure, each sample introduction system path is arranged radially around the ionization chamber 14 so that the path from outside the vacuum chamber to the ionization chamber 14 via the sample introduction system holder 8 is straight.

(Problems to be Solved by the Invention) In a conventional mass spectrometer, each sample introduction system is attached to the vacuum chamber 12 by an independent vacuum flange 10, so as many vacuum flanges as there are paths are required.

Therefore, there are problems in that the structure of the sample introduction system becomes complicated, which not only increases costs but also complicates maintenance.

An object of the present invention is to provide an ion source for a mass spectrometer equipped with a sample introduction system that is simple in structure and easy to maintain.

(Means for Solving the Problems) In the ion source of the present invention, all or at least two of the pipes of the plurality of sample introduction systems that introduce gas samples from outside the vacuum chamber of the mass spectrometer into the vacuum chamber are held in common. This common holding part is attached to the vacuum chamber by one vacuum flange, and the sample introduction system pipe is connected to the ionization chamber installed in the vacuum chamber. The connectors for the integrated sample introduction system are connected and integrated.

(Function) Since two or more sample introduction systems are integrally provided on one vacuum flange, the number of required flanges is reduced. Furthermore, since the connector that connects the sample introduction system to the ionization chamber is integrated, there is less work to attach and detach the vacuum flange during maintenance.

(Embodiment) FIG. 1 shows a vacuum chamber and a sample introduction system in an embodiment of the present invention. For comparison with the conventional system shown in FIG. 2, an example in which three sample introduction systems are provided will be described, but the invention is not limited to this.

Reference numeral 26 denotes a 3-path integrated sample introduction system holder, which is made of a metal with good thermal conductivity, and includes a standard sample introduction system pipe 28, a packed column introduction system pipe 30, and a capillary column introduction system pipe 32. Three pipes are provided parallel to each other, and this holding part 26
It is attached to the vacuum chamber 12 by a vacuum flange 34 provided integrally therewith.

Reference numeral 35 designates the ionization chamber of the same electron impact ion source as that shown in FIG. It extends to one end face facing the sample introduction system holder 26, and each inlet faces the pipe lines 28, 30, 32 corresponding to the sample introduction system holder 26, respectively.

42 is the pipe line 28, 30, 3 of the sample introduction system holding part.
2 and the corresponding ionization chamber introduction pipe 3
6, 38, 40, and the second
Three extendable, spherical contact connectors similar to those shown in the figure are connected with considerable freedom, so that the three connectors can also be retracted simultaneously. .

In the sample introduction system holding part 26, the holding part of the standard sample introduction pipe 28 and the other two pipes 30,
A notch 44 is provided so that the holding portion of the conduit 32 is connected to the holding portion of the conduit 3 at a joint having a predetermined cross-sectional area.
A temperature adjusting heater 46 is provided at the holding portion portions 0 and 32. This creates a temperature gradient across the joint between both holding portions, so that the standard sample introduction conduit 28 is kept at a lower temperature than the other two intervening passages 30, 32.

In this embodiment, the pipe line 2 of the sample introduction system holding section 26 is
The paths between the connectors 8, 30, 32 and the connector 42 can be straight, but the paths between the connectors 42 and the introduction pipes 36, 38, 40 of the ionization chamber 35 have bends. Ru. Although this is not preferable, the bent portion of this embodiment does not pose much of a problem in practice.

Comparing this embodiment with the conventional one shown in Fig. 2,
While the one in FIG. 2 requires three vacuum flanges, this embodiment only requires one. This not only simplifies the structure, but also allows three sample introduction systems to be attached and detached at the same time during maintenance by attaching and detaching one vacuum flange.

In the embodiment, a system having three sample introduction systems has been described, but the system can be similarly applied to systems having two or four or more.

Also, an example is explained in which all sample introduction systems are integrated into one vacuum flange, but for example, only the standard sample introduction system can be installed independently as before, and multiple other sample introduction systems can be integrated. . In that case, the effects of the present invention can be exhibited for a plurality of integrated sample introduction systems.

Further, the ion source is not limited to the illustrated electron impact type, but the same applies to other types.

(Effects of the invention) According to the invention, the structure of the sample introduction system of a mass spectrometer is simplified, and the cost is reduced.
Maintenance work also becomes easier.

[Brief explanation of drawings]

FIG. 1 is an end view of a main part showing one embodiment, and FIG. 2 is a sectional view of a main part showing a conventional example. 12... Vacuum chamber, 26... Sample introduction system holding section, 2
8, 30, 32... Sample introduction system conduit, 34... Vacuum flange, 35... Ionization chamber.

Claims (1)

[Scope of utility model registration request] All or at least two of the pipes of the plurality of sample introduction systems that introduce gas samples from outside the vacuum chamber of the mass spectrometer into the vacuum chamber are installed parallel to each other by a common holding part and are integrated. The holding part is attached to the vacuum chamber by one vacuum flange, and the connector for connecting the sample introduction system pipe line to the ionization chamber installed in the vacuum chamber is for the integrated sample introduction system. A connected and integrated ion source.