JP2007010442A - Gas chromatograph - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas chromatograph capable of acquiring three-dimensional chromatogram without using a coolant. <P>SOLUTION: A constitution is adopted, wherein a passage switch part of a valve 7 or the like is provided on the outlet side of a column 1 on the upstream side and a sample component eluted from the column 1 is distributed into a column 2 or a column 3 by the passage switch part, and the passage switch part is switched periodically. Since many chromatograms by the column 2 or the column 3 can be acquired successively relative to each fraction acquired by cutting and dividing the sample component eluted from the column 1 periodically, the three-dimensional chromatogram can be acquired by arraying the chromatograms in time series. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a gas chromatograph, and more particularly to a gas chromatograph for obtaining a three-dimensional chromatogram.

  One of gas chromatography analysis techniques is to obtain a three-dimensional chromatogram using two different columns. This is because two different types of columns are connected in series, and the elution components from the upstream first column are fractionated by cooling and trapping with liquid nitrogen at regular time intervals. A plurality of chromatograms are obtained in time series by being sequentially introduced into the second column and further separated (for example, see Patent Document 1).

FIG. 4 shows a schematic configuration of the flow path of such a conventional gas chromatograph.
In the figure, a gas chromatograph is configured by arranging a sample introduction unit 6, column 1, column 2, and detector 4 in order from the upstream side along the carrier gas flow path, and on the flow path between the column 1 and the column 2 Are provided with two cold spots 11 and 12 which are locally cooled by being injected with a refrigerant such as liquid nitrogen. The cold spots 11 and 12 are configured to be cooled alternately by switching at a predetermined time T. When the cold spots 11 and 12 are not cooled, the temperature of the cold spots 11 and 12 is room temperature or the columns 1 and 2 are accommodated. It becomes the temperature of an oven (not shown).

The analysis by the gas chromatograph configured as described above is performed as follows.
(1) A sample is introduced from the sample introduction unit 6 and is first roughly separated by the column 1 and is eluted at the cold spots 11 and 12. At this time, for example, if the cold spot 12 is cooled, the carrier gas passes through the cold spot 12 as it is, but the sample component is trapped here.
(2) When the refrigerant injection to the cold spot 12 stops and the cold spot 11 is cooled instead, the sample components trapped in the cold spot 12 are desorbed and introduced into the column 2, where they are separated and detected. The first chromatogram is obtained as detected by the vessel 4. At this time, the subsequent eluate from the column 1 is stopped by the cold spot 11 that has been cooled, so that the ongoing separation in the column 2 is not affected.
(3) When the time T elapses, the cold spot 12 is cooled again, and the temperature of the cold spot 11 rises. The sample component stopped at the cold spot 11 is desorbed and moves to the cold spot 12, and further the column 1 Subsequent effluents from are added to this and trapped.
(4) When the time T further elapses and the temperature of the cold spot 12 rises, the state of (2) is obtained, and the fractional component trapped in the cold spot 12 is introduced into the column 2, and the second chromatogram is obtained. can get.
(5) Thereafter, the above (2), (3) and (4) are periodically repeated, and a large number of chromatograms are sequentially obtained. By arranging these in time series, a three-dimensional chromatogram is obtained. Can be obtained.

US Pat. No. 6,547,852

According to the three-dimensional chromatogram obtained as described above, more information can be obtained as compared with the chromatogram obtained from a single column. Therefore, there is a problem that the operation is dangerous and the operation cost is high.
This invention is made | formed in view of such a situation, and it aims at providing the gas chromatograph which can obtain a three-dimensional chromatogram, without using a refrigerant | coolant.

In order to solve the above problems, the present invention provides a flow path switch unit such as a valve on the outlet side of the first column on the upstream side, and the sample component eluted from the first column by the flow path switch unit is supplied to the second column. Alternatively, it is configured to distribute to the third column, and the flow path switch unit is switched at a constant time period.
With such a configuration, a large number of chromatograms are sequentially obtained from the second column or the third column for each fraction obtained by separating the sample components eluted from the first column at a fixed period. A three-dimensional chromatogram can be obtained by arranging them in an array.

  Since the present invention is configured as described above, a three-dimensional chromatogram can be obtained by switching the flow path switch unit at an appropriate cycle without using dangerous and costly liquid nitrogen.

The gas chromatograph apparatus provided by the present invention has the following characteristics. That is, the first feature is that a flow path switch unit such as a valve is provided on the outlet side of the first column on the upstream side so that the sample components eluted from the first column are distributed to the second column or the third column. The second feature is that the flow path switch unit is configured to be switched at a constant time period.
Therefore, the basic configuration of the best mode is a gas chromatograph apparatus having these configurations.

FIG. 1 is a flow chart showing an embodiment of the present invention. This will be described with reference to the illustrated example. In the figure, the same components as those in FIG. 4 are denoted by the same reference numerals, and the description thereof is omitted.
This embodiment is different from the conventional example shown in FIG. 4 in that a valve 7 is provided on the outlet side of the upstream column 1. The valve 7 is a four-way valve having ports a to d. A column 1 is connected to the port a, a column 2 is connected to the port b, and a column 3 is connected to the port c. Further, a makeup gas flow path 9 having a resistance tube 8 is connected to the port d. Thus, the elution component from the column 1 is distributed to the column 2 or the column 3 at a constant period. Detectors 4 and 5 are arranged on the outlet side of the column 2 and the column 3, respectively. Columns 2 and 3 are of the same type and size, and are different from column 1.
The valve 7 is alternately switched at a constant cycle between a state where each port is connected as shown by a solid line and a state where each port is connected as shown by a dotted line by a valve drive mechanism (not shown).
Note that the resistance tube 8 adjusted so as to have substantially the same resistance as that of the column 1 is provided for flowing a makeup gas of the same type as the carrier gas into either the column 2 or the column 3.

FIG. 2 schematically shows sample component peaks eluted from each column. Hereinafter, the operation of the apparatus of this embodiment will be described with reference to FIGS.
(1) In the valve 7, for example, the sample is introduced from the sample introduction unit 6 in a state where the flow paths are connected as shown by the solid line, and the sample components roughly separated in the column 1 are first eluted and introduced into the column 2. Then, it is separated and detected by the detector 4.
(2) When time T elapses and the valve 7 is switched and the flow path is connected as shown by the dotted line, the eluted components from the column 1 are introduced into the column 3, where they are separated and detected. 5 is detected.
(3) In this way, the valve 7 is switched at every time T, and as shown in FIG. 2 (A), the fraction obtained by separating the eluted components from the column 1 at every time T is alternately distributed to the columns 2 and 3. It is done.
(4) Thereby, as an output of the detector 4, as shown in FIG. 2B, chromatograms obtained by separating odd-numbered fractions are obtained one after another.
(5) Similarly, as an output of the detector 5, as shown in FIG. 2C, chromatograms obtained by separating even-numbered fractions are obtained one after another.
(6) A three-dimensional chromatogram can be obtained by rearranging these chromatograms in time order.

FIG. 3 shows another embodiment of the present invention.
The basic configuration of the present embodiment is the same as that of the first embodiment, and the same components as those in FIG. The difference from Example 1 is that the eluted components from the column 2 and the column 3 are detected by a common detector 4 to obtain a chromatogram. With such a configuration, the analysis condition setting is restricted so that the chromatograms of the column 2 and column 3 do not overlap, but there is an advantage that the apparatus configuration is simplified.

  As mentioned above, although the Example was described, this invention is not limited to this. For example, in the above embodiment, the flow path is directly switched using the valve 7, but a switching method called a Deans switch is used to switch the gas flow direction by changing the pressure balance near the branch point of the flow path. It may be used to configure the flow path switch unit.

  The present invention can be used for a gas chromatograph.

It is a figure which shows one Example of this invention. It is a figure explaining operation | movement of this invention. It is a figure which shows the other Example of this invention. It is a figure which shows the conventional structure.

Explanation of symbols

1 column
2 column 3 column 4 detector 5 detector 6 sample introduction part 7 valve 8 resistance tube 11 cold spot 12 cold spot

Claims (2)

A carrier gas flow path through which a flow-controlled carrier gas flows, a sample introduction section for introducing a sample into the carrier gas flow path, and a column system comprising a plurality of columns for separating the introduced sample into its components. A gas chromatograph comprising a detector for detecting each component, wherein the column system is selected by the first column on the upstream side, the flow path switch section provided on the outlet side thereof, and the flow path switch section. A gas chromatograph comprising a second column and a third column that are communicated with the outlet side of the first column and provided with switching means for switching the flow path switch unit at a constant time period. The gas chromatograph according to claim 1, wherein the outlet side flow paths of the second column and the third column are connected to one common detector.

Images