Solid-phase extraction and GC analyses of select agricultural pesticides and metabolites in stream water

The occurrence of agricultural pesticides in surface waters around the USA has created a concern over the status of safe drinking water. Solid-phase extraction (SPE) or liquid-liquid extraction (LLE) is usually employed to concentrate trace levels of pesticides in water samples to concentrations that are measurable with advanced chromatographic instruments. We describe here a SPE and capillary gas chromatographic (GC) procedure to extract and concentrate trace levels of select agricultural pesticides and metabolites from stream water. Our SPE and GC method provides high sensitivity, with recoveries between 85% to 95%, and high reproducibility for 9 of the pesticides studied. The described method provided marginal recoveries of 19 and 60% for the atrazine metabolites.