Gas flow cell with a built-in gas chromatograph for ultraviolet detection and identification

Abstract

This instrument consists of a gas flow cell with a small, built-in gas chromatograph. The dimensions are such that it can be directly placed in the gas cuvette holder in most of the UV spectrophotometers available. The construction material is filled PTFE, which is an electrically conductive material. By applying a voltage over the whole instrument the gas flow cell, including the gas chromatograph with its injector, can be heated to a stable temperature. The gas-chromatographic column is 80 mm long and, in order to get a sufficient plate number, ordinary HPLC packing materials are used. The best results have been obtained by using Nucleosil C₁₈(10 µm) as the support and didecyl phthalate as the liquid loading at about 4%m/m; for an 80-mm column about 1000 theoretical plates are obtained. UV spectral scanning of compounds is obtained by interrupting the gas glow when the separated compound is in position in the light beam.