JPS6315550B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for blocking gas flow between a gas chromatograph and another analytical device when the two are combined.

An analysis method is used in which a gas chromatograph is coupled with another analytical device such as a mass spectrometer, and sample components separated by the gas chromatograph are introduced into the mass spectrometer to fix or analyze the sample components. In this case, a device for blocking gas flow is provided between the gas chromatograph and the analyzer connected thereto. This device is usually called a solvent diver, etc., but it not only collects the solvent of the sample flowing out from the gas chromatograph, but also transfers the chromatograph effluent components that do not need to be analyzed by the subsequent analyzer to the analyzer. This is used to prevent the inflow of substances, thereby preventing contamination of the subsequent analyzer with unnecessary components. For this purpose, the present invention relates to a gas flow cutoff device provided between a gas chromatograph and an analysis device connected thereto.

As shown in Fig. 1, a conventional solvent diver has a branch pipe B in the middle of a pipe system T that connects a gas chromatograph G and another analyzer M, and connects this branch pipe to an exhaust pump P via a valve V. Connect and
In the case of unnecessary components, the valve V is opened to remove them by suction. In this configuration, the pipe line from the branch point of branch pipe B to valve V and the space inside the valve are closed spaces, and a part of the sample components flowing out from the gas chromatograph diffuse into this closed space and gradually become Since the gas flows out toward the subsequent analyzer M, the peak of the outflow component on the gas chromatograph may be observed as a tailed peak in the subsequent analyzer M, or it may be mixed into the outflow component of the next gas chromatograph. Therefore, there was a problem that ghosts appeared in the analysis results by the subsequent analyzer M.

The present invention has been made to solve the above-mentioned problems of conventional solvent divers.

As shown in FIG. 2, the present invention includes a silica capillary K extending from the gas chromatograph and a sample introduction tube extending from the subsequent analyzer M. The inner diameter of the open end side of the pipe system L is set so that the outer diameter of the silica capillary K can be inserted into the pipe system L, and a side opening b is provided to connect the silica capillary K to the exhaust system Q. The present invention provides a gas introduction cutoff device in which side opening b is opened and closed by inserting the gas from the open end to the back of opening b or stopping before opening b. The present invention makes the above-described structure possible by utilizing the flexibility, high chemical stability, and heat resistance of the silica capillary. The present invention will be explained below with reference to Examples.

FIG. 3 shows a main part of an embodiment of the present invention. This example relates to an apparatus that combines a gas chromatograph and a mass spectrometer. When a gas chromatograph and a mass spectrometer are coupled, a molecular separator is used to remove the carrier gas from the gas chromatograph effluent gas and concentrate sample components before introducing them into the mass spectrometer. In FIG. 3, S is a molecular separator, and a jet type molecular separator is used. The jet-type molecular separator has a nozzle n and an orifice f facing each other in an exhaust chamber C, the nozzle n being connected to a gas chromatograph G, and the orifice being connected to a mass spectrometer M. A tube system L extends from the mass spectrometer up to this nozzle portion, and a silica capillary K extending from the gas chromatograph G is inserted into the nozzle n. The nozzle n is provided with an opening b on the side, and this opening is connected to the exhaust chamber C.
is open to The exhaust chamber C is connected to the vacuum pump P, and therefore corresponds to a part of the exhaust system Q described above.

When introducing the gas chromatograph effluent components into the mass spectrometer with the above configuration, use the silica capillary K.
into the nozzle n and close the opening b with the capillary K itself. In this way, the gas flowing out from the gas chromatograph is ejected from the nozzle n, and at this time, light carrier gas molecules such as helium diffuse more laterally within the jet than the sample component molecules, so the gas enters the orifice f. In this case, the concentration of sample components is significantly increased. When stopping the introduction of the sample into the mass spectrometer, the tip of the capillary K is moved back to the left side of the opening b. This opens opening b, and the gas chromatograph outflow immediately flows into exhaust chamber C through opening b and is removed by suction by pump P. In this case, since the opening of the nozzle n has a large outflow resistance, most of the chromatograph outflow gas flows out through the opening b and is eliminated. In addition, since the pressure inside the nozzle n has decreased, even if some of the chromatograph outflow gas flows out from the nozzle n, a jet cannot be formed and it is diffused between the nozzle n and the orifice f, leading to the mass spectrometer. cannot enter. Airtightness between the silica capillary K and the nozzle n is achieved by a compatible fit between the two, and no lubricant is used. If pure carrier gas is introduced near the capillary insertion end of nozzle n, the carrier gas will flow out from the nozzle capillary insertion end and prevent outside air from entering. The compatibility with K can be quite loose. Of course, packing may be used between the nozzle n and the capillary K.

FIG. 4 shows another embodiment of the present invention in which a silica capillary K extending from a gas chromatograph G is inserted into an inflow pipe L' extending from a nozzle of a molecular separator S to a nozzle. It is connected to a vacuum pump P with an opening b, and its usage is as described in Section 3 above.
This is the same as the example in the figure.

The device of the present invention has the above-mentioned configuration, and there is no branch pipe as in the conventional example, and the side of the main gas pipe is used as a valve, so a closed space is not formed as in the conventional example. Various problems caused by retention of sample components are all eliminated.

[Brief explanation of the drawing]

FIG. 1 is a side view of a conventional example, FIG. 2 is a side view showing the general configuration of the present invention, FIG. 3 is a vertical side view of one embodiment of the present invention, and FIG. 4 is another embodiment of the present invention. It is a longitudinal side view of an example. G... Gas chromatograph, M... Other analyzer, K... Silica capillary extending from the gas chromatograph, L... Sample introduction tubing system extending from the analyzer M, b... Tubing system Side opening of L, Q...exhaust system connected to opening b.

Claims (1)

[Claims] 1. A silica capillary extended from a column of a gas chromatograph is slidably inserted into the open end of a sample introduction tube system of another analyzer connected to the gas chromatograph, and a side surface of the capillary insertion part of the sample introduction tube system is inserted. A chromatography system characterized in that an opening is provided in the silica capillary and connected to an exhaust system, and the opening is opened or closed by adjusting the insertion depth of the silica capillary into the sample introduction pipe system. Sample introduction cut-off device between graph and subsequent analyzer.