Determination of pesticides in environmental waters by solid-phase extraction and gas chromatography with electron-capture and mass spectrometry detection

A group of pesticides with different chemical structures was determined by solid-phase extraction on LiChrolut EN cartridges and gas chromatography with electron-capture detection or mass spectrometry. The parameters affecting the solid-phase extraction process were optimized and the responses obtained by both GC detection systems were compared. The use of an electron-capture detector enabled the organochlorine pesticides studied to be determined at ngl(-1) levels whereas mass spectrometry under selective ion monitoring acquisition enabled levels of low mu gl(-1) to be reached. The R.S.D. (n=6) of the method in tap water was lower than 8.1% for electron-capture and mass spectrometric detection. The methods developed were used to determine the pesticides studied in tap and river water and some pesticides could be found in Ebro river and Ebro delta water.