A Simple Directly Combined Gas Chromatographic-Infrared Spectrometric System for Identification of Low Molecular Weight Hydrocarbons

Abstract

A simple directly combined gas chromatographic-infrared spectrometric system suitable for the identification of low molecular weight hydrocarbon-type compounds is reported. It incorporates a 30-m × 0.5-mm i.d. SCOT Silicone DC-550 column and a micro light pipe gas cell (volume 0.6 ml) fitted on a kinematic mounting into the sample compartment of a conventional ir spectrophotometer. Sensitivity is enhanced by a gas chromatographic fraction concentrator, a 10-cm × 1.0-mm i.d. 10% Silicone SE-30/Chromport A (80 to 100 mesh) column, situated upstream of the gas cell. The performance of the system is demonstrated for synthetic mixtures of C6 — C10 paraffinic, olefinic, and aromatic types of hydrocarbons. Infrared spectra can be taken at 5- to 6-min intervals at levels of 14 to 19 µg per sample component. This system has potential for application in the field of trace analysis, e.g., air pollution.