JP2603867Y2 - Gas chromatograph-infrared spectrophotometer - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a gas chromatograph in which each component separated by a gas chromatograph (hereinafter referred to as GC) is qualitatively determined by an infrared spectrophotometer (hereinafter referred to as IR).
It relates to an infrared spectrophotometer (GC-IR).

[0002]

2. Description of the Related Art IR is an extremely effective means for analyzing the structure of a substance. In addition to obtaining information reflecting chemical bonds, there is little change in the quality of a measured substance and nondestructive analysis is possible. , Is used very widely. In particular, among the IRs, the one using light interference (Fourier transform infrared spectrophotometer FTIR) measures all wavelengths at the same time, and can effectively use light because a slit is not required, thereby improving brightness and sensitivity. , Scanning speed and the like.

[0003] However, IR has a disadvantage that it is difficult to analyze a mixture.
A composite device (GC-IR) combined with the above has been used.

As a GC-IR, a branch pipe is provided in front of a GC detector, and a part of a separated component from the GC is taken out and guided to an IR cell (light pipe).
The components separated from the GC are trapped on the cooled window plate and I
A system leading to R is known.

[0005]

However, the light pipe method of the conventional GC-IR needs to be taken out of the oven of the GC, so that a temperature difference occurs between the GC and the IR, and a chromatogram of the GC is obtained. And the infrared absorption spectrum of IR may cause a time difference. further,
For measurement by IR, a photometric unit for IR measurement was required.

Further, the method of trapping on a window plate cannot perform continuous measurement, and the components that can be measured are limited.

Therefore, an object of the present invention is to solve the above-mentioned problems and to provide a GC-IR which can easily perform continuous measurement and can obtain an infrared absorption spectrum without a temperature difference and a time difference.

[0008]

According to the present invention, in order to solve the above-mentioned problems, a part of a GC column is used as an IR photometer,
The photometric unit is housed in a GC column oven.

Therefore, the present invention is a GC-IR in which each component separated by GC is detected by a GC detector, and the separated components are qualitatively determined by an infrared spectrophotometer.
A pair of light guides connected to a light source section and a detection section of the IR are connected to a part of the column.

Here, the GC column may be a capillary column or a normal microbore column, but the material of the column is determined by using a part of the column as an IR measuring section. Glass is preferred. The inner surface of the column is preferably coated with a metal having a high reflectance so that infrared light is reflected. Examples of the metal having a high reflectance include gold and silver.

The position of the column used as the IR measuring section is determined by GC
Is preferable in the vicinity of the end of the column before the detector.

The connection of the IR light source unit and the detection unit to the GC column by the light guide is performed by providing a light guide insertion hole in the column, inserting the light guide into the hole, and guiding the light from the IR light source unit. The light from the column may be sent to the detection unit by a light guide, or a part of the column may be cut and connected to the light guide.
The means is not particularly limited.

The light guide may be, for example, an optical fiber, a light pipe or the like.

As a light source of the IR, for example, a heat radiator such as a glow bar, a Nernst glower, or a nichrome wire is used. As a detector, an MCT detector, a pyroelectric detector, or the like is used, but is not limited thereto.

When a dispersion-type IR is used, a dispersive element is required, and when an interference-type IR is used, an interferometer is required.

[0016]

According to the present invention, since the GC column itself serves as a photometric unit, there is no temperature difference between the GC side and the IR side when detecting, and there is no time difference between the GC side and the IR side chromatogram.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic structural view of the GC-FTIR of the present invention. In FIG. 1, reference numeral 1 denotes a GC capillary column, which is housed in a column oven 4 maintained at a high temperature.

At one end of the capillary column 1 is a vaporization chamber 2
Is connected, and the introduced sample is vaporized here. The sample is introduced by using a microsyringe or the like.

Further, the vaporization chamber 2 is connected to a flow path from the carrier gas source 3 so that the vaporized sample is introduced into the capillary column 1. Note that a splitter 5 is provided at the lower end of the vaporization chamber 2, and the amount of branching to the capillary column 1 is determined from the ratio of the resistance of the split resistance tube 3 to the resistance of the capillary column 1. At the other end of the capillary column 1, a detector (eg, FID)
A hydrogen detector for sample combustion and air for auxiliary combustion are introduced into the FID detector 6 from respective gas sources 7 and 8. In addition, a capillary resistance tube 10 is connected to the subsequent stage of the FID detector 6, and the flow resistance in the detector 6 is adjusted. Further, it is also connected to a flow path from a makeup gas source 9 so that the detector 6
The inside is cleaned.

A photometric section 11 is formed between the capillary column 1 and the detector 6. The photometric section 11 has an outer periphery of the capillary column 1 coated with a metal having a high reflectance, and a light source section of the FTIR. The detection unit is connected to optical fibers 12 and 13.

The optical fiber 12 condenses the light from the interferometer 14 with the condenser mirror M4 and sends it to the photometric unit 11.
The optical fiber 13 sends the light transmitted through the photometer 11 to the detector. M5 and M6 are condenser mirrors, 15 is M
3 shows a CT detector.

The interferometer 14 includes a light source L, a condenser mirror M
1. Consists of a fixed mirror M2, a movable mirror M3, and a beam splitter BS. As a result, the light emitted from the light source L becomes a parallel light flux at M1, and is reflected by the beam splitter BS, half toward the fixed mirror M2, half through the transmission mirror M3,
After being reflected and combined, the light passes through the condenser mirror M4 to the photometric unit 11. If there is a difference of δ / 2 in the distance between the beam splitter BS and the fixed mirror M2 and the movable mirror M3, the movable mirror M3
A light path difference of δ is generated between the light wave reflected by the mirror and the light wave reflected by the fixed mirror M2, so that the synthesized wave cancels or strengthens and the detected signal becomes a function of δ, and the interference curve give. An infrared spectrum can be obtained by Fourier-transforming this signal.

With the above configuration, the measurement of a sample is performed as follows.

First, a sample is introduced into the vaporization chamber 2, the sample is vaporized, and sent to the capillary column 1 by a carrier gas. The separation of the sample occurs in the capillary column 1, and the separated sample components are sequentially sent to the photometric unit 11. The sample component sent to the photometric unit 11 is irradiated with infrared light from the interferometer 14 via the optical fiber 12. Photometry unit 1
After being subjected to the light absorption peculiar to the sample component in 1, the transmitted light is sent to the condenser mirror M5 via the optical fiber 13, and the infrared spectrum can be obtained by the MCT detector 15 through the condenser mirror M6.

The sample components sequentially sent to the photometer 11 are sent to the FID detector after passing through the photometer 11, and
Is obtained.

[0027]

[Effects of the Invention] In the present invention, since the column itself is a photometric unit, there is no difference in temperature between detection on the GC side and the IR side, and measurement at high temperatures and pyrolysis GC which are difficult with the conventional light pipe method are not possible. Can also be applied to the measurement of

Further, the time difference between the chromatograms on the GC side and the IR side is reduced, and the branching of the separated component to the IR side becomes unnecessary, so that the entire amount can be detected.

Further, since there is no need to form a special cell on the IR side, the installation area on the IR side is reduced.

[Brief description of the drawings]

FIG. 1 is a diagram of an embodiment of the present invention.

[Explanation of symbols]

 1: Capillary column 6: FID detector 11: Photometry unit 12, 13: Optical fiber 14: Interferometer 15: MCT detector

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01N 30/74 G01N 21/35 G01N 30/60

Claims (1)

(57) [Scope of request for utility model registration] 1. A gas chromatograph-infrared spectrophotometer, wherein each component separated by a gas chromatograph is detected by a detector for a gas chromatograph, and the separated components are qualitatively determined by an infrared spectrophotometer. A part of the column is a photometric unit, and a pair of light guides connected to a light source unit and a detecting unit of the infrared spectrophotometer are connected to the photometric unit, and the photometric unit is housed in a column oven. Gas chromatograph-infrared spectrophotometer.