JPH04323558A - Gas chromatograph fourier-transform type infrared spectrophotometer - Google Patents

Abstract

PURPOSE:To perform separation, qualititative analysis and quantitative analysis of the trace components of unstable materials, especially vital samples and agricultural chemicals, etc., with high sensitivity and good reproducibility using a GC-FT/IR system and to enable GC-FT/IR and GC to be readily used alone when using a glass-packed column in a gas chromatograph. CONSTITUTION:The total constitution of a GC-FT/IR analytical system includes a gas chromatograph(GC), a Fourier-transform infrared spectrophotometer and the interface of GC-IR. The gas chromatograph consists of a flow regulator 1, a sample inlet 2, a separation column 3, a detector 15 and a data processing unit. The Fourier-transform infrared spectrophotometer consists of a sample room, a spectroscope, a CPU and a control portion.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to GC-FT/IR, and in particular, the present invention relates to GC-FT/IR.
The purpose was to measure simultaneously with R and to further improve the detection sensitivity of IR. In addition, in GC, it is possible to use multiple detectors and various separation columns (packed, capillary, etc.), and among these, a glass packed column can be easily used for GC-FT/IR and GC alone. Regarding the GC-FT/IR that has been made possible.

0002

[Prior Art] Figure 1 shows a configuration diagram of a conventional GC-FT/IR.
A conventional example will be explained below.

[0003] In a gas chromatograph (GC), a carrier gas (usually N2 gas) is adjusted to an optimum flow rate with a flow rate controller 1, guided to a sample injection port 2, and a measurement sample is injected from the injection port using a microsyringe or the like, and then the sample is injected into a separation column. Introduced into 3, 3′,
Separate the target component. The separated components are divided into two channels by a channel divider 4, one for the GC detector and one for the IR measurement cell. The flow path divider and relay connector 7 are made of stainless steel pipe 5,
Controller 6 connected at 5' and provided with a separate pipe
It is heated by The current division ratio is determined by the flow path resistance between the resistance coil 8 connected from the relay connector and the IR measurement cell 11.

A stainless steel pipe 9 connects the relay connector to the measurement cell, and the pipe and the IR measurement cell are heated by separately provided controllers 10, 10'. In the system of this method, the material of the flow path system piping, IR cell cylinder, etc. was stainless steel. Therefore, depending on the sample, adsorption or decomposition occurs on the tube wall, resulting in a decrease in detection sensitivity and deterioration in quantitative performance. Furthermore, since the IR measurement cell is of a circulation type, when measuring the spectrum of a target component, the time spent in the cell is short, making it impossible to increase the number of scans and making it difficult to set the scan timing. Therefore, there are problems in that the S/N ratio of the spectrum cannot be expected to improve and that the reproducibility of the spectrum cannot be obtained.

[0005]

[Problems to be Solved by the Invention] The above prior art is as follows: 1)
Since the sample is measured in a flow manner without stopping it in the FT-IR measurement cell, there is a limit to the number of FT-IR integrations, making it impossible to measure trace components. 2) The ratio of components separated by gas chromatography to the GC detector and FT-IR detection side can be easily changed depending on the type of resistance coil. 3) Both packed columns and capillary columns can be easily used for separation columns in gas chromatographs, but when checking the separation performance with GC alone, especially glass packed columns are better than GC alone and GC.
- The purpose is to provide an analyzer that can be easily used for FT/IR, and that can stably analyze trace components.

[0006]

[Means for solving the problem] In order to achieve the above objective, in order to increase the number of FT/IR integrations, 1) FT/IR
The flow cell was designed as a stopped flow system so that the measurement can be performed with the carrier gas stopped.

[0007] 2) In order to easily divert the measurement component to the FT/IR side to the maximum extent possible, the division ratio can be determined using a resistance coil method.

3) In order to prevent the sample from being adsorbed and decomposed in the flow path system, it is possible to obtain stable quantitative results by using fused silica and glass-lined gas cells for the flow path system piping.

4) GC-FT/IR GC as an independent GC
In particular, we focused on glass packed columns to make them easy to use, and we made this possible by arranging each detector and flow path divider around the circumference of the sample injection port.

0010

[Operation] The GC-FT/IR analysis system
This system identifies components by separating them using C and performing spectrum measurements using FT/IR. At that time, depending on the sample, it is necessary to separate it using a capillary column in a high separation mode, and the amount per component is often extremely small. Therefore, it is necessary to increase the detection sensitivity of FT/IR. For these reasons, it may be possible to increase the amount of sample introduced into the GC, but there is a limit to the amount of sample that can be added, especially for capillary columns in high separation mode, so this is not very effective. It is also possible to increase the number of FT/IR scans, but it is said that the number of scans (n) contributes to reducing the noise level of It has no effect on improving. (This makes it easy to use a wide-bower capillary column that can increase the amount of sample while obtaining relatively high resolution.)
An effect can be obtained by selecting the resistance coil connected to the relay connector so that as much of the component injected into C and separated as possible is diverted to the IR gas cell side. In addition, by equipping one gas chromatograph with multiple detectors, we have considered the placement of the detectors and flow path dividers so that you can easily use the detector that suits your purpose independently. , the effect can be obtained in terms of use.

[0011]

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 2 and 3. A carrier gas whose flow rate is adjusted to match analysis conditions by a carrier flow regulator 1 of a gas chromatograph is guided to a sample injection port 2. The sample is injected with a microsyringe or the like through the injection port and gasified. The gasified sample is separated by a separation column 3 or 3'. The column is housed in a column constant temperature bath, and the temperature is controlled to match the analysis conditions. The column outlet is connected to a flow path divider 4. The carrier gas that has passed through the column is divided into three channels by a channel divider, and then connected to a piping pipe 5 such as a fused silica tube or a glass-lined pipe.
5' and 5'' are connected to a relay connector 6. The piping is kept at an optimum temperature by a controller 7.

[0012] The outlet side of the relay connector has three flow paths, one
The flow path is led to a gas chromatograph detector via a resistance coil 8, and the other two flow paths are led to a sample chamber of an infrared spectrometer via piping 9, 9'. One side is the measurement gas cell 1
0 and the other to a dummy gas cell 11. Both pipes are made of inert material, and the transfer line and measurement gas cell are kept at a constant temperature using separately provided control power supplies 12 and 12'. controlled.

The outlets of the measurement gas cell and the dummy gas cell are connected to a two-channel switching electromagnetic valve 13. Normally, the measurement gas cell side is left open, and when the target component is detected by the gas chromatograph, the electromagnetic valve is closed. Switch the flow path to open the dummy gas cell side, store the target component in the measurement cell, and perform FT/IR scans several tens to hundreds of times to perform spectrum measurement with improved S/N. . Control of the electromagnetic valve is performed by a timer controller 14 provided separately.

FIG. 3 shows the sample injection port 2 of the gas chromatograph.
, detectors 15, 15', and flow path divider 4. Especially when using a glass packed column as a separation column, the same column can be easily used for GC measurement alone and via the flow path divider. The reason is that it is possible to perform simultaneous GC and FT/IR measurements. This is because the detector and the flow path divider are arranged on the circumference around the sample injection port.

[0015]

According to the present invention, when measuring FT/IR spectra in a GC-FT/IR system, GC and F
By dividing the sample into T/IR appropriately and storing the target component in the gas cell, it is possible to improve the S/N even for trace components by increasing the number of FT/IR scans. . In addition, in order to minimize decomposition, adsorption, diffusion, etc. of the measurement sample in the flow path system,
By using fused silica capillary pipes, glass-lined pipes, etc., and by minimizing the dead volume at the connections, we are taking precautions to reduce sample diffusion in the flow path system and to avoid deterioration of resolution. Therefore, there is an optimal GC-FT/IR effect.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a conventional GC-FT/IR system.

FIG. 2 is an explanatory diagram of the GC-FT/IR system of the present invention.

FIG. 3 is an explanatory diagram of a gas chromatograph (GC) of the present invention.

[Explanation of symbols]

1...Flow rate controller, 2...Sample injection port, 3...Separation column, 4
...Flow path divider, 5...Piping pipe, 6...Relay connector, 7
...Controller, 8...Resistance coil, 9...Plumbing pipe, 1
0... Gas cell for measurement, 11... Dummy gas cell, 12... Control power supply, 13... Solenoid valve, 14... Timer controller, 15... Detector.

Claims (5)

[Claims] Claim 1: In a gas chromatograph-Fourier transform infrared spectrophotometer (hereinafter referred to as GC-FT/IR),
The multi-components separated by the separation column of the gas chromatograph are divided by a flow path splitter into an infrared spectrophotometer (hereinafter referred to as IR) and a gas chromatograph (hereinafter referred to as GC), and while the GC detects and records, the components are analyzed using the IR. GC-FT/IR characterized by simultaneous measurement. [Claim 2] In the GC-FT/IR according to Claim 1, a relay connector is provided behind the flow path divider, and a resistance coil is inserted on the GC side to improve the detection sensitivity of the carrier gas. A GC-FT/IR flow path divider characterized by being able to easily change the division ratio. 3. In the GC-FT/IR flow path divider according to claim 2, the flow path system on the IR side has two flow paths, a measurement gas cell and a dummy gas cell, and a solenoid valve for flow path switching is provided behind the flow path system. A gas cell for IR using a GC-FT/IR channel split method, which is characterized by being able to hold a sample during IR measurement, and minimizing pressure fluctuations when switching channels. 4. In the GC-FT/IR flow path divider according to claim 2, the capillary tube through which components to be measured such as the flow path divider, the relay connector, the GC detector, and the IR gas cell pass is used for adsorption, decomposition, etc. of the sample. A GC characterized by using a field silica tube aimed at preventing
- FT/IR flow path divider. 5. In the GC-FT/IR according to claim 1, when a glass column for GC analysis is used, the outlet side of the glass column is connected to a flow path divider and various GC detectors (flame ionization detector, thermal GC-FT/IR characterized in that a flow path divider and various detectors are provided at positions on the circumference of the sample injection port so that they can be easily connected to ionization detectors, flame photometer detectors, etc. .