SUPERCRITICAL-FLUID EXTRACTION OF TRIAZINE HERBICIDES - A POWERFUL SELECTIVE ANALYTICAL METHOD

Atrazine and three of its metabolites (Deset [desethylatrazine], Met [ desethyl-desisopropyl-2-hyroxyatrazine], 2-Hydroxy [2-hydroxyatrazine] ) were extracted from three different environmental matrices: soils, s ediments and plants. Standard extraction remained constant to allow in tercomparison. The recovery of the target analytes varied significantl y from one matrix to one another. An extraction performed with modifie d supercritical CO2 is compared to a classical solid-liquid extraction [SLE] with methanol: water (4:1). SFE does not require the clean-up o f the extract that classical methods usually do for any of the sample types. The method enables analysis of all target analytes. Although re coveries are generally good, lower recoveries are obtained for natural samples. Classical extraction gave better recoveries, but does not en able characterisation of metabolites, indeed, several clean-ups are ne eded to remove interfering coextraction products. Although SFE may giv e lower recoveries than traditional extraction method for atrazine, it is an accurate analytical method that allows quantification of polar pesticides with high reproducibility and specificity, avoiding coextra ction of important quantities of the sample matrix.