DETERMINATION OF PHENYLUREA PESTICIDES IN WATER BY DERIVATIZATION WITH HEPTAFLUOROBUTYRIC ANHYDRIDE AND GAS-CHROMATOGRAPHY MASS-SPECTROMETRY

The application of direct gas chromatographic methods to phenylurea pesticides is difficult because these compounds are thermally unstable and rapidly give isocyanates and amines when using standard gas chromatography. However, derivatization to more thermally stable compounds can be used. Procedures for solid-liquid extraction, catalytic heptafluorobutyrylation, clean-up and determination by GC-MS of phenylurea pesticides in water samples are reported. Detection limits are of the order of 10-50 ng/1.