DETERMINATION OF A VARIETY OF CHEMICAL CLASSES OF PESTICIDES IN SURFACE AND GROUND WATERS BY OFF-LINE SOLID-PHASE EXTRACTION, GAS-CHROMATOGRAPHY WITH ELECTRON-CAPTURE AND NITROGEN-PHOSPHORUS DETECTION, AND HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH POSTCOLUMN DERIVATIZATION ANDFLUORESCENCE DETECTION

Octadecyl (C-18)-bonded porous silica was evaluated for the extraction of triazines, organochlorine, carbamates and acidic pesticides from s urface and ground water. Gas chromatography with selected detection me thods (electron-capture detection, nitrogen-phosphorus detection, mass spectrometry) and liquid chromatography-post-column derivatization fl uorescence detection was employed for the determination of 32 pesticid es. Recoveries varied from 52 to 102%. The recoveries of triazines obt ained using C-18 extraction cartridges and conventional liquid-liquid extraction (LLE) are compared. The Limit of detection for seventeen or ganochlorine compounds was better than 0.003 mu g/l and the limit of d etection for other 15 analytes was better than 0.06 mu g/l. The propos ed analytical methodology was applied to analyze pesticides in surface and ground-water samples of the Lassithi Plateau, Crete, Greece. (C) 1998 Elsevier Science B.V. All rights reserved.