JPH088448Y2 - Hydrogen flame ionization detector for gas chromatograph - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an improvement of a hydrogen flame ionization detector used as a detector of a gas chromatograph.

[Conventional technology]

The gas chromatograph shows a cylinder 10 as shown in FIG.
Mobile phase carrier gas (H ₂ , He, Ar, etc.) from valve 11
Flow at a constant rate while adjusting with, the sample is injected in the sample introduction part 12, the stationary phase of the separation column 13 (the stationary phase packed in the column in the case of packed column, the column wall in the case of capillary column is applied or chemically This is an apparatus for separating the components in the sample by performing concentration equilibrium by adsorption or absorption distribution with the bound stationary phase), and analyzing by the detector 14.

As the detector 14, there are various types such as a thermal conductivity detector, an electron capture type detector, a flame photometric detector, and a hydrogen flame ionization detector is often used as a highly sensitive detector. This hydrogen flame ionization detector uses formaldehyde, formic acid, etc.2.
It shows high sensitivity to all organic compounds except those of No. 3.

This hydrogen flame ionization detector, as shown in the cross-sectional view of the main part of FIG. 2, creates a hydrogen flame C by a hydrogen combustion device in which hydrogen gas is separately introduced from a hydrogen gas conduit B in a column A, and creates a hydrogen flame C together with a carrier gas. When the separated sample is flowed, the organic components in the sample generate ions centering on carbon in the process of combustion, so a voltage is applied to the hydrogen flame C from the high-voltage power source D, and a current generated in proportion to the ion concentration is generated. It is measured by the collector E and the detection circuit F.

[Problems to be solved by the invention]

At present, it is said that even if a sample is ionized by a hydrogen flame ionization detector for a gas chromatograph and the ions are collected by a high electric field and taken out as a current signal, only about 1 ppm of the sample contributes to detection. Therefore, in order to increase the sensitivity of the hydrogen flame ionization detector, it is required to increase the ionization efficiency in the hydrogen flame.

The present invention has been made in view of such problems, and its purpose is to promote the ionization caused by the burning of the sample.

[Means for solving problems]

That is, in order to solve the above problems, this invention is
In a hydrogen flame ionization detector for a gas chromatograph, which passes a sample through a hydrogen flame installed in the middle of a column and ionizes the sample to detect the sample, a sample excitation device was installed before the hydrogen flame of the column. Characterize.

[Action]

The specific sample separated in the separation column and flowing with the carrier gas is excited by the sample excitation device before passing through the hydrogen flame, and the atoms or molecules in the sample become high energy levels, and the sample in this state When passing through a hydrogen flame, is highly ionized during combustion. Therefore, the sensitivity of the detector is improved.

〔Example〕

Specific embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of the essential parts of a hydrogen flame ionization detector for a gas chromatograph according to the present invention. In this figure, 1 is a column in which the separated sample flows with a carrier gas. Reference numeral 2 is a conduit for flowing hydrogen gas, and 3 is a hydrogen flame. Reference numeral 4 is a high voltage power source for applying a voltage to the hydrogen flame 3, 5 is a collector for collecting ions generated in the hydrogen flame, and 6 is a detection circuit connected to the collector 5.

Further, 7 is an excitation device for exciting the sample flowing from the column 1 side. The excitation device 7 is, for example, an ultraviolet ray generator. This ultraviolet ray generator generates ultraviolet rays with a mercury lamp and uses the ultraviolet rays to excite a sample.

That is, the main point of this invention is a separation column (not shown).
It is to install a device for exciting a specific sample separated inside and flowing together with the carrier gas with ultraviolet rays or the like before passing through the hydrogen flame 3. When excited in this way, atoms or molecules in the sample have a high energy level, and when the sample in this state passes through the hydrogen flame 3, the rate of ionization during combustion increases. Alternatively, the excitation device 7 may be a discharge device.

[Effect of device]

The hydrogen flame ionization detector for a gas chromatograph according to the present invention is configured as described above, so that the sensitivity as a detector is improved and it becomes possible to detect even a trace amount of components more accurately.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a hydrogen flame ionization detector for a gas chromatograph according to the present invention, FIG. 2 is a sectional view of an essential part of a conventional hydrogen flame ionization detector, and FIG. 3 is a principle diagram of a gas chromatograph. . 1 ... Column, 2 ... Hydrogen gas line, 3 ... Hydrogen flame 4 ... High-voltage power supply, 5 ... Collector, 6 ... Detection circuit 7 ... Sample excitation device

Claims (1)

[Scope of utility model registration request] 1. A hydrogen flame ionization detector for a gas chromatograph for detecting a sample by passing the sample through a hydrogen flame of a hydrogen combustion device installed in the middle of the column, and before the hydrogen flame of the column. A hydrogen flame ionization detector for a gas chromatograph, characterized in that a sample excitation device is installed in the.