JPS648786B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an analyzer in which a gas chromatograph and a mass spectrometer are directly connected, and particularly to an analyzer equipped with a flow path switching device that allows column exchange while the ion source is operating.

Figure 1 shows an example of a conventional device that directly connects a gas chromatograph and a mass spectrometer. A sample injected from the sample inlet 2 is carried by a carrier gas 1 (mainly helium is used) into a column 4 in an oven 3, and is separated into each component. Although the outlet pressure of the column 4 is approximately atmospheric pressure, the ion source 9 of the mass spectrometer 10 is maintained at a high vacuum by the high vacuum evacuation system 11, so the carrier gas is separated and removed by the evacuation system 8 in the separator 7. , only sample components are flowed into the ion source 9. This allows for direct analysis between a gas chromatograph and a mass spectrometer. Since samples are generally diluted with solvents such as acetone, these solvents flow into the ion source and contaminate the ion source. In order to prevent such adverse effects, conventionally, a solvent removal valve 6 is often provided directly connected to the flow path to bypass and exhaust the solvent when the solvent component flows out. FIGS. 2 and 3 show the structure of this solvent removal valve and an example of flow path switching.

Figure 2 shows the valve flow path during measurement.
There is a solvent removal valve inner cylinder 16 that tightly slides on the inner surface of the solvent removal valve outer cylinder 15, and by moving this position with a knob 17, the flow path can be changed between the state shown in FIG. 2 and the state shown in FIG. It is possible to switch. In the position shown in FIG. 2, the inner cylinder 16 connects the column 4 side and the separator 7 side, and in the position shown in FIG. . Packing 1
8 is used for airtight sealing with the outside.

Various types of columns 4 are used in gas chromatographs depending on the purpose of analysis, and they often need to be replaced. In FIG. 1, when the column 4 is removed, atmospheric pressure is reached at the column connection port 5, and air flows in from the solvent removal valve 6. This is the second
In the state shown in Fig. 3, air is not completely sealed and flows into the high-vacuum ion source 9, burning out the thermal filament used for ionization.
When replacing the column, the ion source must be stopped. Therefore, the ion source 9
Since the ion source 9 is operated again, it takes time to complete the measurement, which may cause conditions setting or the ion source 9 to become contaminated.

An object of the present invention is to provide a gas chromatograph-mass spectrometer device that is equipped with means that does not require stopping the operation of the ion source even when replacing a column.

Conventional solvent removal valves were only capable of operating as shown in Figures 2 and 3, but the present invention has a structure that allows operations as shown in Figure 5, and furthermore, the carrier gas can be measured even when the column is removed. Install a flow path and a valve that allow the same flow path to flow into the separator.

An embodiment of the present invention is shown in FIG. 4, and FIG. 5 shows the operating state of the solvent removal valve when the column is removed. Here, the operation for removing the column will be explained.

In FIG. 4, valves 12 and 14 are closed and valve 13 is opened. At the same time, the solvent removal valve 6 is switched to the state shown in FIG. This is the third
This is the same as the knob 17 in the figure rotated 180 degrees. In this state, the carrier gas enters from the exhaust port of the solvent removal valve outer cylinder 15 and flows into the separator 7 side, so by keeping the flow rate of the carrier gas at this time the same as the amount flowing from the column 4 during measurement, 9 under the same conditions as during measurement.
Even if the column 4 inside the oven 3 is removed, only a small amount of carrier gas will flow out to the atmosphere through the column connection port 5, and no air will flow into the system.
The ion source 9 can be left in operation.

Therefore, even when replacing the column 4, the ion source 9
Since there is no need to stop the process, measurement can be performed immediately, improving analysis processing efficiency. For example, ion source 9
In order to let air flow into the ion source 9, re-evacuation and
It usually takes several hours to reheat and reach a steady state, but the time savings can be significant.

It would be even more efficient to link these various valves with switches and set them automatically. Further, the same applies if the valve structure is a three-way valve. The solvent removal valve needs to have a structure with a small dead volume, and although an example is shown in the figure, it does not necessarily have the same effect even if it does not have the structure shown in the figure.

According to the present invention, there is no need to stop the operation of the ion source even when replacing a column, and continuous measurement becomes possible.

[Brief explanation of the drawing]

Figure 1 is a conventional flow path connection diagram, Figures 2 and 3 are
Figure 4 shows an example of the operation of a conventional solvent removal valve, Figure 4 is a diagram showing a flow path during column exchange in an embodiment of the present invention, and Figure 5 shows the operation of the valve in the embodiment of Figure 4. FIG. 4... Column, 6... Solvent removal valve, 12...
...Valve A, 13...Valve B, 14...Valve C, 16...Solvent removal valve inner cylinder.

Claims (1)

[Claims] 1 flowing a carrier gas through the column from a carrier gas source so as to separate the sample injected into the column, whereby the separated sample components in the effluent exiting the column are separated from the carrier gas therein by a separator; a first flow path system leading to a mass spectrometer; a second flow path system leading a solvent component in the effluent from the column to an exhaust system; and a second flow path system leading a carrier gas from the carrier gas source without passing through the column. A gas chromatograph-mass spectrometer device, characterized in that the gas chromatograph-mass spectrometer device is equipped with a third flow path system for supplying water to the separator, and means for switching between the first, second and third flow path systems.