Evaluation of an automated solid-phase extraction system for the enrichment of organochlorine pesticides from waters

An automatic method for the determination of organochlorine pesticides (OCP s) in water samples was developed. The analytes are preconcentrated onto a customized RP-C-18 column and subsequently eluted with 80 mul of ethyl acet ate. Gas chromatography with electron capture detection is used for their s eparation and selective detection. Detection limits for 10 ml sample volume s range from 0.01 to 0.1 ng ml(-1), with standard deviations between 4 and 6%. The average recovery at a fortification level of 2 ng ml(-1) is 92%. Th e method was used to screen OCPs in natural waters collected near agricultu ral areas and also to tap waters. Positive findings were confirmed by gas c hromatography with mass spectrometric detection. Finally, the adsorption/de gradation of OCPs in natural pond water containing a high level of suspende d matter was examined; some OCPs were found to be degraded and irreversibly adsorbed on suspended matter present in the water. (C) 2001 Elsevier Scien ce B.V. All rights reserved.