JPS5838444A - Chromatographic mass spectrometer - Google Patents

Abstract

PURPOSE:To aim at preventing a nozzle from clogging possibly produced at the time of column replacements and improving analyzing effciency, by leading a purge gas to flow from the nozzle to a connecting part of column upon passing through a plate installed between the opposed nozzles of a separator. CONSTITUTION:A gas passage hole F is made up inside a plate V and its one end is open to the face opposite to a nozzle N1 on the chromatograph side of the plate while the other end is open to the upper end side of a shank part of the plate. The plate's shank part is fitted to a jet separator body B and its airtightness is kept up by an O-ring. The part of the plate V where the gas passage hole F is open, is extruded upward from the body B, the upper side opening of the gas passage hole F being connected to a purge gas source G and the same He used as a carrier gas of the chromatograph is used for the purge gas. With this, analyzing efficiency can be improved.

Description

[Detailed description of the invention] The present invention relates to chromatographic mass spectrometers.

Mass of sample components flowing out from the gas chromatograph.

When analyzed by a spectrometer, a molecular separator is installed in the gas flow path between the chromatograph and the mass spectrometer to remove the carrier gas from the chromatograph effluent gas and concentrate the sample components before introducing them into the mass spectrometer. establish. As a molecular separator, a jet-type molecular separator is used in one or more stages, which uses a pair of nozzles facing each other and uses the fact that the way the jet of gas ejected from one nozzle spreads out depending on the weight of the gas molecules. . On the other hand, in a chromatograph mass spectrometer, in order to prevent gases that do not need to be analyzed, such as the solvent used in the chromatograph, from flowing into the mass spectrometer, the chromatograph is used for mass analysis during periods when sample components are not flowing out from the chromatograph. In order to block the gas flow reaching the meter, a plate is inserted between the opposing nozzles of the jet-type molecular separator described above. The present invention particularly relates to the above-mentioned gas flow blocking device attached to a jet-type molecular separator in a chromatographic mass spectrometer.

When replacing a column in a chromatograph mass spectrometer, the chromatograph side nozzle of the jet-type molecular separator mentioned above tends to become clogged. Conventionally, a method as shown in FIG. 1 has been used to prevent this.

C is a chromatography column, ■ is an ion source of a mass spectrometer, S is a jet-type molecular separator, and Nl and N2 are opposing nozzles. A space between the opposing nozzles N1 and N2 is connected to an exhaust pump P. When replacing the column, when column C is removed while the exhaust pump P is activated to keep the mass spectrometer (including the ion source) in a vacuum, outside air is sucked into the separator S, and fine particles in the outside air are removed. This causes the chromatograph side nozzle N1 to become clogged. In order to prevent this, the purge gas is fed from halfway between the column connection part and the nozzle N1. Even in this case, since the purge gas flows to the pump P through the nozzle N1, fine particles in the pipe clog the nozzle N1.

The present invention was made with the object of improving the drawbacks of the above-mentioned conventional methods for preventing clogging of the nozzle of a jet-type molecular separator that occurs during column replacement.

As mentioned above, in order to stop gas from flowing into the mass spectrometer when unnecessary, a plate is provided between the opposing nozzles of the jet separator so that it can be moved in and out. To provide an apparatus that allows purge gas to flow from a nozzle to a column connection. The present invention will be explained below with reference to Examples.

FIG. 2 shows an embodiment of the present invention.

Nl and N2 are opposed nozzles of a jet-type molecular separator, N2 on the right side is connected to the Ion Riko of the mass spectrometer, and Nl is connected to the join (J) on the left side. Column C is connected to joint J by a cap nut U. A space between the opposing nozzles Nl and N2 is connected to an exhaust pump P. ■ is a plate that can be moved in and out between nozzles Nl and N2 and can slide vertically as shown in the figure. When introducing the sample components flowing out from column C into Ion Riko, plate ■ is pulled up, and the figure shows ■
The figure shows the case where the gas is introduced between the nozzles Nl and N2 to block the gas flow from the column toward the ion source. A hole F for a gas flow path is bored in the plate V, one end of which opens on the surface of the plate facing the chromatography side nozzle Nl, and the other end opens at the upper end of the handle of the plate. It opens on the side. The handle part of the plate fits into the main part B of the jet separator, and is kept airtight by an O-ring. Play) Gas flow path F at the handle part of V
The open portion thereof projects upward from the main body B, and the upper end opening below the gas flow path is connected to a purge gas source G.

Helium, the same as the carrier gas in the chromatograph, is used as the purge gas. In the position shown in FIG. 2 where the plate (3) blocks the gas flow path, the opening at the lower end of the gas flow path F coincides with the opening of the nozzle N1. At this position, gas source G
When the valve (2) between the column and the plate V is opened, the purge gas flows from the nozzle N1 toward the column C. When removing column C from joint J for column replacement, etc., lower plate v to the position shown in Figure 2 and open valve V. In this case, the purge gas is blown out and the particles are blown out from the joint J, and no clogging of the nozzle N1 occurs at all.

The upper and lower parts of the plate v are manually operated in the embodiment shown in FIG.
The upper end of the handle of the plate ■ is pivotally fixed to a cam K, and when a handle H attached to the cam K is tilted to the left, the plate ■ can be pulled up. Valve V is also opened and closed manually. Of course, even if an electromagnetic valve is used as the valve V, and the switch is opened and closed in conjunction with the up and down of the plate (■), the switch is closed and the electromagnetic pulp v is opened at the position shown in Fig. 2 when the plate (V) is lowered. Alternatively, the upper and lower parts of the plate V may also be moved using electromagnets, and both the valve V and the plate (2) may be operated electrically.

The device of the present invention has the above-described configuration, and by flowing purge gas in the opposite direction to the original gas flow in the chromatograph side nozzle where clogging is likely to occur, it not only prevents inhalation of dust but also improves the flow from the column joint to the nozzle. Since it even removes microflow particles that were in the channel, it not only prevents the nozzle from clogging when the column is removed for column replacement, improving analysis efficiency, but also prevents the nozzle from becoming clogged during analysis. Even in such cases, the nozzle can be unclogged by lowering the plate and sending purge gas under high pressure.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the entire conventional example, and FIG. 2 is a vertical sectional side view of a main part of an apparatus according to an embodiment of the present invention. C... Column S... Jet type molecular separator,
■...Ion source of the mass spectrometer, Nl, N2...Opposing nozzle ■Zle, X...Gas flow blocking plate, F...Gas flow path provided in plate P, B... Main body of jet-type molecular separator, G... gas source of purge gas. Agent Patent Attorney Kosuke Hayashi 7-

Claims (1)

[Claims] A gas flow passage is formed in a gas flow blocking plate that is installed so that it can go in and out between the opposing nozzles of a jet-type molecular separator that is installed in the middle of the gas flow path that connects the chromatograph and the mass spectrometer. A chromatograph mass spectrometer that has an opening on the surface of the plate facing the chromatograph side nozzle, and allows purge gas to flow in from the other end.