RAPID MICRO LIQUID-LIQUID-EXTRACTION METHOD FOR TRACE ANALYSIS OF ORGANIC CONTAMINANTS IN DRINKING-WATER

The applicability and performance of a micro liquid-liquid extraction method for trace analysis of organic compounds in drinking water is reported. Tap water samples of 400 mi are saturated with sodium chloride and extracted once with 500 mu l of toluene. Extracts are analyzed directly without further treatment by gas chromatography using simultaneous electron-capture and nitrogen-phosphorus detection. Recoveries of 82 organic compounds, including organochlorine and organophosphorus insecticides, triazine and acetanilide pesticides, chlorinated anilines and phenols from tap water samples spiked at 50 to 500 ng/l were determined and relative standard deviations were calculated. For 68 compounds the recoveries were higher than 50%. The mean relative standard deviations at spiking levels of 50, 100 and 500 ng/l were 7.9, 6.6 and 5.2%, respectively. The extraction method proved to be rapid, simple and inexpensive. In most cases compounds were reproducibly detected well below the European Union maximum tolerance level for pesticide residues in drinking water of 100 ng/l.