Determination of organophosphorus pesticides and related compounds in water samples by membrane extraction and gas chromatography.

A membrane extraction-gas chromatography method was developed for determination of organophosphorus pesticides and related compounds including methamidophos, DDVP, dimethoate, methyl parathion, parathion, thiophosphoric acid trimethyl ester, and thiophosphoramidic acid dimethyl ester in water samples. In this method, surface-modified acetic cellulose membranes were used to extract the target analytes in water samples, the extracted analytes were back-extracted into a small amount of methanol, and gas chromatography with pulsed flame photometric detector (GC-PFPD) was used to determine the concentrations of target analytes in the extracts. The recoveries obtained for the target analytes spiked into the water samples ranged from 66 to 94%. The method detection limit for each target analyte was 0.05 microg L(-1). The method developed in this study had shown the advantages of being cheap, simple, fast, and reliable. It had been used successfully to determine the concentrations of target analytes in river water samples.