USING SUPERCRITICAL-FLUID EXTRACTION AND ENZYME IMMUNOASSAYS TO DETERMINE PESTICIDES IN SOILS

We used supercritical fluid extraction (SFE) to extract pesticides fro m soil samples; the extraction recoveries with supercritical fluids we re comparable to those achieved with conventional Soxhlet and sonicati on techniques. For polar and thermally labile pesticides, extraction w ith supercritical fluids combined with enzyme immunoassays allowed for faster extraction and analysis, fewer sample preparation steps (no ne ed for extract cleanup and concentration), and more sensitive and sele ctive analyses. We discuss the use of SFE to extract alachlor, atrazin e, captan, carbofuran, metolachlor, and 2,4-D from freshly spiked tops oil samples containing up to 10% humic acid by weight, and subsequent analysis by enzyme immunoassays.