Purge-and-trap gas chromatography–mass spectrometry in the analysis of volatile organochlorine compounds in water

Abstract

A purge-and-trap concentrator combined with GC–MS or GC–MS–MS was evaluated for the determination of volatile organochlorine compounds in aqueous samples. A laboratory-made pulsed spray-and-trap technique has been developed for extraction. For optimization studies, a flow-rate of purge gas at 40 ml/min for 16 min, desorption temperature at 200°C for 3 min, and a cryo-trap at the injection port were used to produce the highest sensitivity for detection of volatile organochlorine compounds. Using sample extraction by purge-and-trap or laboratory-made pulsed spray-and-trap, the limits for detection of organochlorine compounds in aqueous solution, with selected-ion monitoring of GC–MS as well as neutral loss mode of GC–MS–MS, were estimated. The detection limits at the low ng/l levels are described. The application of the methods to the determination of organochlorine compounds in real samples was tested by analyzing a landfill leachate sample. Comparison with the normal purge-and-trap technique is made and the advantage of pulsed spray extraction operating with aqueous systems containing surfactants is also discussed.