SUPERCRITICAL-FLUID EXTRACTION OF CARBAMATE PESTICIDES FROM SOILS ANDCEREALS

A method for the supercritical fluid extraction of carbamate pesticide s (propoxur, aminocarb, carbaryl and methiocarb) from soil and cereal samples using CO2 is proposed. Extractions were at 378 bar and 54 degr ees C. Analytes were determined in the extracts by HPLC with fluoresce nce detection after post-column derivatization. Recoveries from spiked soil ranged between 39.6 and 91.7%, depending on analyte and soil com ponents. Lowest recoveries were from sandy soils. Aminocarb could not be recovered from any soil using CO2. Recovery of aminocarb from diato maceous earth was improved by adding methanol to the extraction cell p rior to SFE, but the effect was not observed in soil samples. Recoveri es for propoxur and aminocarb from spiked wheat were about 75%, and on ly between 30-50% for aminocarb from corn and oats, and carbaryl from wheat. Fat was coextracted using CO2 and retained in the trap together with the analytes, however, appropriate rinsing solvent allowed on-li ne clean-up of the extract.