Determination of organochlorine pesticides in ground water using solid-phase microextraction followed by dual-column gas chromatography with electron-capture detection.

A rapid, sensitive, convenient, and highly quality-assured method is presented for the determination of 19 organochlorine pesticides (OCPs) in small samples (10 ml) of ground water. Samples are initially fortified with 2,4,5,6-tetrachloro-m-xylene (surrogate) and decachlorobiphenyl (retention time marker), then extracted with a 30-micron thickness polydimethylsiloxane solid-phase microextraction fiber. The analytes collected are thermally desorbed in a heated gas chromatographic inlet, separated using independent fused-silica capillary columns ("primary" and "confirmatory"), and detected using electron-capture detection.