Liquid chromatographic trace enrichment with on‐line capillary gas chromatography for the determination of organic pollutants in aqueous samples

Abstract

Abstract Trace enrichment for the GC analysis of a series of chlorinated pesticides and polychlorinated biphenyls (PCBs) in aqueous samples has been achieved through a simple on‐line technique involving sorption on an LC micro‐precolumn followed by direct elution into a gas chromatograph with hexane. A 5‐m retention gap coupled to the capillary GC column served as the recipient of a relatively large sample volume ( ca. 100 μl) introduced into the GC. Partially concurrent solvent evaporation during sample introduction allowed a large sample capacity. Recoveries of more than 95% were observed for the majority of the compounds studied. Using 1.0 ml aqueous samples, detection limits of less than 1 ppt were found. The applicability of the developed method was demonstrated for a river water sample.