JP3159793U - Headspace sample introduction device - Google Patents

Abstract

In a headspace sample introduction device for introducing a pressurized gas into a sample container, taking out the sample gas by its internal pressure, and introducing it into a gas chromatograph, the pressurized gas introduction tube and the sample gas discharge tube share the pipeline. To prevent cross contamination. A terminal end of one of a pressurized gas introduction pipe 11 and a sample gas discharge pipe 12 connected to the same port of a valve 7 is inserted into the end of the other pipe and doubled. Tube 17 is formed. As a result, the pressurized gas introduction pipe 11 and the sample gas discharge pipe 12 can be connected to the same port of the valve without sharing the pipe line. Further, a pressurized gas introduction pipe 11 is connected to a branch point provided in the sample collection pipe 10. With this configuration, the pressurized gas introduction pipe 11 and the sample gas discharge pipe 12 are completely separated from each other, and there is no shared portion. [Selection] Figure 1

Description

  The present invention relates to gas chromatography, and more particularly to a headspace sample introduction apparatus for analyzing components volatile from a liquid / solid sample by gas chromatography using a headspace method.

  The headspace gas analysis method volatilizes components having a relatively low boiling point by heating a liquid / solid sample enclosed in a sample container to a certain temperature for a certain period of time, and removes the components from the upper space (headspace) in the container. The contained gas is sampled and introduced into a gas chromatograph or the like for analysis. The sampling method is a method in which the sample container is pressurized to a certain pressure with pressurized gas, then the sample gas is taken out with its internal pressure, and a certain amount is measured with a measuring tube and introduced into a gas chromatograph through a gas sampling valve. It is.

FIG. 4 shows an example of the flow path configuration of a conventional headspace sample introduction apparatus. A substantially similar flow path configuration is also illustrated in Non-Patent Document 1, for example.
In FIG. 4, a valve 7 is a 6-port rotary valve, and switches the connection state between the ports to either a state indicated by a solid line or a state indicated by a dotted line. A sample to be analyzed is sealed in a sample container 15 arranged on a rack 16 and heated to a predetermined temperature.

The operation of this apparatus is roughly as follows.
In the state where the valve 7 is a dotted line, the needle 9 is inserted into the upper space in the sample container 15, the electromagnetic valve 5 is opened, the pressurized gas is sent from the pressurized gas introduction pipe 11, and the inside of the sample container 15 is pressurized. Next, when the solenoid valve 5 is closed and the solenoid valve 6 is opened, the pressurized headspace gas (sample gas) flows out through the sampling tube 10 to fill the measuring tube 8, and the surplus sample gas is sampled. The gas is discharged from the gas discharge pipe 12 through the electromagnetic valve 6. In this state, when the valve 7 is switched to the solid line state, the carrier gas of the gas chromatograph flows into the measuring tube 8, sampling is performed by transporting the sample gas filling the tube to the column 2, and gas chromatograph analysis is started. Is done.

Catalog “Agilent G1888 Headspace Sampler” Agilent Technologies, 2007 Edition

In the configuration of FIG. 4, the pressurized gas introduction tube and the sample gas discharge tube are connected to the same port of the valve, so the portion of FIG. For this reason, part of the sample component remains attached to the inner wall of the common pipe line, etc., and when the next sample container is pressurized, this residual component is mixed into the pressurized gas and introduced into the sample container for cross contamination. May cause.
The present invention has been made in view of the above circumstances, and an object thereof is to prevent cross-contamination caused by a pressurized gas introduction pipe and a sample gas discharge pipe sharing a pipeline.

In order to solve the above-mentioned problems, the present invention provides a headspace sample introduction device comprising the following 1 to 7, wherein one of a pressurized gas introduction tube and a sample gas discharge tube connected to the same port of the valve. A double pipe is formed by inserting the end of one duct into the end of the other duct.
1. 1. Sample collection tube provided with a needle inserted into the sample container at the tip. 2. Pressurized gas introduction pipe for introducing a gas having a predetermined pressure for pressurizing the inside of the sample container. 3. Measuring tube for measuring a certain amount of sample gas taken out from the sample container through the sampling tube 4. Sample gas discharge pipe for discharging the sample gas that has passed through the measuring pipe. 5. Carrier gas introduction pipe for introducing a carrier gas adjusted to a predetermined pressure / flow rate. 6. Carrier gas delivery pipe for delivering the carrier gas toward the column of the gas chromatograph A first state in which the carrier gas introduction tube, the metering tube, and the carrier gas delivery tube communicate with each other and the pressurized gas introduction tube and the sample collection tube communicate with each other; the sample collection tube and the metering tube; A valve having a plurality of ports for switching between the sample gas discharge pipe and the second state in which the carrier gas introduction pipe and the carrier gas delivery pipe communicate with each other. With this configuration, the pressurized gas introduction pipe and the sample gas The discharge pipe can be connected to the same port of the valve without sharing the pipe line.
As another solution, a pressurized gas introduction pipe is connected to a branch point provided in the sampling pipe. With this configuration, the pressurized gas introduction tube and the sample gas discharge tube are completely separated, and the shared portion is eliminated.

  Since this invention is comprised as mentioned above, the possibility of the cross contamination resulting from a pressurized gas introduction pipe and a sample gas discharge pipe sharing a pipe line can be excluded.

It is a figure which shows one Example of this invention. It is a figure which shows the detailed structure of one Example apparatus of this invention. It is a figure which shows the other Example of this invention. It is a figure which shows the example of a conventional structure.

FIG. 1 shows an embodiment of the present invention.
In the figure, pressure regulators 1 and 3 adjust the carrier gas and the pressurized gas to predetermined pressures, respectively. Column 2 performs gas chromatographic separation. The back pressure regulator 4 keeps the pressure of the sample gas at a constant value. As described above, the valve 7 is a 6-port rotary valve, and switches the connection state between each port between a state indicated by a solid line and a state indicated by a dotted line. A sample to be analyzed is sealed in a sample container 15 arranged on a rack 16 and heated to a predetermined temperature.
In addition, the right side part of the chain line C shown in the drawing is the apparatus of this embodiment, and the left side of the chain line C belongs to the gas chromatograph apparatus connected thereto.

  In each port of the valve 7, a sample collection tube 10 provided with a needle 9 inserted into the sample container 15 at the tip, and a pressurized gas introduction tube 11 for introducing a pressurized gas adjusted to a predetermined pressure via the electromagnetic valve 5. The measuring tube 8 for measuring a certain amount of the sample gas taken out from the sample container 15, the sample gas discharge tube 12 for discharging the sample gas that has passed through the measuring tube 8 through the electromagnetic valve 6, is adjusted to a predetermined pressure / flow rate. A carrier gas introduction pipe 13 for introducing the carrier gas and a carrier gas delivery pipe 14 for delivering the carrier gas toward the column 2 are connected. Among them, the pressurized gas introduction pipe 11 and the sample gas discharge pipe 12 are connected to the same port through a double pipe 17, which is a feature of the apparatus of this embodiment.

The apparatus according to this embodiment operates as follows.
First, in a state where the valve 7 is indicated by a dotted line, the needle 9 is inserted into the upper space in the sample container 15, the electromagnetic valve 5 is opened, the pressurized gas introduction pipe 11 through the double pipe 17, the measuring pipe 8, and the sampling pipe The pressurized gas is fed through 10 to pressurize the inside of the sample container 15. Next, when the solenoid valve 5 is closed and the solenoid valve 6 is opened, the pressurized headspace gas (sample gas) flows out through the sampling tube 10 to fill the measuring tube 8, and the surplus sample gas is reduced to two. The sample gas is discharged from the sample gas discharge pipe 12 through the solenoid valve 6 through the heavy pipe 17. At this time, the pressure of the sample gas in the measuring pipe 8 is maintained at a constant value by the back pressure regulator 4.

  In this state, when the valve 7 is switched to the solid line state, the carrier gas of the gas chromatograph flows from the carrier gas introduction tube 13 to the measuring tube 8, and a constant pressure and a constant volume of the sample gas filling the tube is supplied to the carrier gas delivery tube 14. Then, sampling is performed by conveying to column 2 and gas chromatograph analysis is started.

The double tube 17 is formed by inserting the end portion of the pressurized gas introduction tube 11 into the end portion of the sample gas discharge tube 12. An example of the specific configuration is shown in FIG.
As shown in the figure, the double pipe 17 includes an inner pipe 17a, an outer pipe 17b, and a different-diameter three-way joint 17c. The inner pipe 17a and the outer pipe 17b are both stainless steel pipes. An example of the size is described. The inner pipe 17a has an inner diameter of 0.5 mm and an outer diameter of 1.5 mm, and the outer pipe 17b has an inner diameter of 2.1 mm and an outer diameter of 3.2 mm. Yes, the different diameter three-way joint 17c is a general commercial product.

  In FIG. 2, the outer tube 17 b communicates with the sample gas discharge pipe 12 via a different-diameter three-way joint 17 c, and constitutes the end portion of the sample gas discharge pipe 12 as a flow path. The inner pipe 17a is such that the end portion of the pressurized gas introduction pipe 11 passes through the different-diameter three-way joint 17c as it is and is inserted into the outer pipe 17b, whereby a double pipe 17 is formed.

  As described above, in this embodiment, the pressurized gas introduction pipe 11 and the sample gas discharge pipe 12 connected to the same port of the valve 7 form a double pipe 17 at both ends. Since the gas path is separated into the inner tube 17a and the outer tube 17b, cross-contamination due to residual components in the sample gas can be prevented.

FIG. 3 shows another embodiment of the present invention.
In the figure, components denoted by the same reference numerals as those in FIG. 1 are the same as those in FIG. 1 and have the same functions. In this embodiment, avoiding connecting the pressurized gas introduction pipe 11 and the sample gas discharge pipe 12 to the same port of the valve 7, a branch point B is provided in the middle of the sample collection pipe 10, and the pressurized gas is provided to this. The difference from the first embodiment is that the introduction pipe 11 is connected. With this configuration, the pressurized gas introduction pipe and the sample gas discharge pipe are completely separated from each other, so that there is no shared portion, and the possibility of cross contamination is eliminated.

  The operation of the apparatus of the present embodiment is that the pressurized gas flows from the pressurized gas introduction pipe 11 to the sample gas discharge pipe 12 without passing through the valve 7 when the pressurized gas is introduced, that is, the path through which the pressurized gas passes is different. Except for this point, it is the same as the case of the first embodiment described above, and its operation and effect are also substantially the same.

  The present invention can be used for gas chromatography.

DESCRIPTION OF SYMBOLS 1 Pressure regulator 2 Column 3 Pressure regulator 4 Back pressure regulator 5 Solenoid valve 6 Solenoid valve 7 Valve 8 Measuring pipe 9 Needle 10 Sampling pipe 11 Pressurized gas introduction pipe 12 Sample gas discharge pipe 13 Carrier gas introduction pipe 14 Carrier Gas delivery pipe 15 Sample container 16 Rack 17 Double pipe 17a Inner pipe 17b Outer pipe 17c Different diameter three-way joint

Claims (2)

1. 1. Sample collection tube provided with a needle inserted into the sample container at the tip. 2. Pressurized gas introduction pipe for introducing a gas having a predetermined pressure for pressurizing the inside of the sample container. 3. Measuring tube for measuring a certain amount of sample gas taken out from the sample container through the sampling tube 4. Sample gas discharge pipe for discharging the sample gas that has passed through the measuring pipe. 5. Carrier gas introduction pipe for introducing a carrier gas adjusted to a predetermined pressure / flow rate. 6. Carrier gas delivery pipe for delivering the carrier gas toward the column of the gas chromatograph A first state in which the carrier gas introduction tube, the metering tube, and the carrier gas delivery tube communicate with each other and the pressurized gas introduction tube and the sample collection tube communicate with each other; the sample collection tube and the metering tube; A valve having a plurality of ports that switches between the second state in which the carrier gas introduction pipe and the carrier gas delivery pipe communicate with each other, and a head space comprising the above 1 to 7 In the sample introduction device, the end of one of the pressurized gas introduction pipe and the sample gas discharge pipe connected to the same port of the valve is inserted into the end of the other pipe 2. A headspace sample introduction device characterized by forming a double tube. 1. 1. Sample collection tube provided with a needle inserted into the sample container at the tip. 2. Pressurized gas introduction pipe for introducing a gas having a predetermined pressure for pressurizing the inside of the sample container. 3. Measuring tube for measuring a certain amount of sample gas taken out from the sample container through the sampling tube 4. Sample gas discharge pipe for discharging the sample gas that has passed through the measuring pipe. 5. Carrier gas introduction pipe for introducing a carrier gas adjusted to a predetermined pressure / flow rate. 6. Carrier gas delivery pipe for delivering the carrier gas toward the column of the gas chromatograph A first state in which the carrier gas introduction tube, the metering tube, and the carrier gas delivery tube communicate with each other and the sample gas discharge tube and the sample collection tube communicate with each other; the sample sampling tube, the metering tube, and the A valve having a plurality of ports for switching a second state in which the sample gas discharge pipe communicates with the carrier gas introduction pipe and the carrier gas delivery pipe communicate with each other. In the introduction device, the pressurized gas introduction tube is connected to a branch point provided in the sample collection tube.

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