JPH0119537B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sample introduction device for vaporizing a sample in a gas chromatograph (GC) and sending it to a separation carrier, and in particular, it is capable of switching between split mode and splitless mode with a simple configuration. Regarding a sample introduction device.

Recently, split/splitless type sample introduction devices have been widely used in GC. In this method, when the sample concentration is high, the evaporated sample is split and only a portion is sent to the separation column (split mode), and when the sample concentration is low, the evaporated sample is not split (splitless mode) and the entire amount is sent to the separation column. This method can be switched to send to a separation column.

FIG. 1 shows an example of the device configuration. In the figure, 1 is a vaporizer that evaporates the sample injected from the injection port 2 and sends it to the capillary column (CC) 3. The vaporizer 1 cleans the carrier gas inlet 4, the split outlet 5, and the vicinity of the injection port 2. It has a purge outlet 6 for discharging carrier gas.
7 is a carrier gas source, 8 is a flow meter, 9, 10, 1
1 is a needle valve, 12 is a constant flow valve, 1
3, 14, and 15 are solenoid valves. The dashed line in the figure represents the gas flow in split mode.
The one-dot chain line indicates the gas flow during sampling in the splitless mode, and the two-dot chain line indicates the gas flow during measurement in the splitless mode. As described above, the conventional apparatus has a complicated structure, and therefore, an increase in price is unavoidable.

The present invention has been made in view of the above-mentioned conventional drawbacks, and includes a vaporizer for vaporizing an injected sample and sending it to a separation column together with a carrier gas, the vaporizer having a carrier gas inlet and a split outlet; A carrier gas inlet pipe for supplying the carrier gas to the carrier gas inlet of the vaporizer, a bypass pipe branched from the middle of the carrier gas inlet pipe, and a bypass pipe connected to the split outlet and the discharge pipe of the vaporizer, respectively. The object of the present invention is to provide a sample introduction device that can switch between split mode and splitless mode with a simple configuration by providing a switching valve that selectively connects a bypass pipe and a split outlet to a discharge pipe. There is. Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 2 shows the configuration of one embodiment of the present invention, and the first
Components that are the same as in the figures are given the same numbers. In FIG. 2, the carrier gas generated from the carrier gas source 7 is connected to a flow meter 8 and a constant flow valve 1.
6, is supplied to the vaporizer 1 via the introduction pipe 17 and the introduction port 4. In addition, a three-way valve 1 is installed at the discharge port 5.
8 is connected, and the split gas is discharged through the discharge port 5, the three-way valve 18, the discharge pipe 19, and the needle valve 20. A bypass pipe 21 bypasses between the inlet pipe 17 and the discharge pipe 19, and is connected to the three-way valve 18 via a resistance pipe 22 in the middle.

In the above configuration, the three-way valve 18 is set to allow gas to flow only from the outlet 5 to the valve 20, as shown by the broken line. Therefore, the entire amount of the carrier gas, for example 50 c.c./minute, which has passed through the constant flow valve 16 is introduced into the vaporizer 1;
0.5 cc/min is discharged from outlet 6, 48.5 cc/min is discharged from outlet 5, and the remaining 1 c.c./min is discharged together with the sample.
Sent to CC3.

Next, in the splitless mode, during sample sampling, the three-way valve 18 stops the gas from the exhaust port 5 as shown by the dashed line, and the bypass pipe 2
Open the bypass flow path according to 1. The resistance pipe 22 is given a flow path resistance that is approximately equal to that of the vaporizer 1, and therefore, 48.5 cc/min of carrier gas flows through the bypass pipe 21, and this gas is discharged through the valve 20 and is not supplied to the vaporizer 1. The remaining 1.5cc/min is introduced. Of this, 0.5 cc/min is discharged through the outlet 6, and 1 cc/min of carrier gas is sent to CC3 together with the sample. At this time, the connection part A of CC3 with the vaporizer is cooled, and the sample is trapped and concentrated in that part. When the entire amount of the injected sample is trapped in the part A and the solvent is also discharged from CC3, the three-way valve 18
is switched so that it follows the same broken line flow as in the split mode, and measurement is performed in the splitless mode. At this time, part A of CC3 is heated, so
The trapped sample is thereby vaporized and carried towards the outlet of the CC3 by the carrier gas sent from the vaporizer 1 at a rate of 1 c.c./min.

As described in detail above, according to the present invention, the number of valves including solenoid valves is extremely small compared to the conventional example, and the flow path is also simple, making it extremely advantageous in terms of cost. Furthermore, in this embodiment, the flow resistance of the bypass flow path is made approximately equal to that of the vaporizer, so even when the three-way valve 18 is switched, there is almost no variation in the flow rate.

Although a three-way valve is used in the above embodiment, it goes without saying that this may be replaced with two interlocking valves.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of a conventional example, and FIG. 2 is a diagram showing the configuration of an embodiment of the present invention. 1: vaporizer, 3: capillary column,
4: Carrier gas inlet, 5: Split outlet, 7: Carrier gas source, 17: Carrier gas inlet pipe, 18: Three-way valve, 19: Discharge pipe, 21:
Bypass pipe, 22: resistance pipe.

Claims (1)

[Scope of Claims] 1. A vaporizer 1 which is a vaporizer for evaporating an injected sample and sending it to a separation column together with a carrier gas, and has a carrier gas inlet 4 and a split outlet 5, and a carrier gas inlet 4 of the vaporizer for transmitting the carrier gas. A carrier gas introduction pipe 17 for supplying the carrier gas to the carrier gas, and a bypass pipe 21 branched from the middle of the carrier gas introduction pipe 17.
and a switching valve 18 which is connected to the bypass pipe 21, the split discharge port 5 of the vaporizer, and the discharge pipe 19, respectively, and selectively connects the bypass pipe 21 and the split discharge port 5 to the discharge pipe 19.
A gas chromatograph sample introduction device consisting of. 2. The sample introduction device according to claim 1, wherein the switching valve is a three-way valve.