Atomic emission detector for gas chromatography and supercritical fluid chromatography

Abstract

A recently developed atomic emission source, the microwave plasma torch (MPT), is evaluated as an element-selective detector for gas chromatography (GC) and capillary supercritical fluid chromatography (SFC). The interfaces between the gas chromatograph or supercritical fluid chromatograph and the MPT are described. The effects of plasma and GC-SFC experimental conditions on the emission of analytes are studied. Two alternative types of MPT discharges are identified and their comparative utility in GC-SFC-MPT detection investigated. The introduction of an SFC mobile phase (in this instance CO₂) has less of an effect on the He MPT discharge stability and sensitivity than on a surfatron-sustained He microwave-induced plasma. Either a He or an Ar MPT can be used as an SFC detector for ferrocene. However, a He MPT is necessary if chlorine is to be measured. Figures of merit are given and compared with those obtained from other atomic emission chromatographic detectors.