Using supercritical fluid extraction and enzyme immunoassays to determine pesticides in soils

Abstract We used supercritical fluid extraction (SFE) to extract pesticides from soil samples; the extraction recoveries with supercritical fluids were comparable to those achieved with conventional Soxhlet and sonication techniques. For polar and thermally labile pesticides, extraction with supercritical fluids combined with enzyme immunoassays allowed for faster extraction and analysis, fewer sample preparation steps (no need for extract cleanup and concentration), and more sensitive and selective analyses. We discuss the use of SFE to extract alachlor, atrazine, captan, carbofuran, metolachlor, and 2,4-D from freshly spiked topsoil samples containing up to 10% humic acid by weight, and subsequent analysis by enzyme immunoassays.