Use of supercritical fluid extraction in the analysis of pesticides in soil.

The applicability of supercritical fluid extraction (SFE) in pesticide residue analysis in soil was investigated by analysing real soil samples from field experiments. Additionally, radiotracer batch experiments were performed to study the release of non-extractable residues. High repeatability, accuracy and high selectivity were the most important advantages of SFE in residue analysis. Extracts with low amounts of coextractants from the soil matrix were achieved, allowing extracts to be pooled and concentrated without further clean up steps. Thus, the limited volume of extraction thimbles of the SFE apparatus used could be compensated and insufficiently high limits of determination could be improved. Although the application of methanol-modified supercritical CO(2) was a time-saving extraction procedure which reduced solvent usage and solvent waste, SFE efficiency proved only competitive to conventional slurry and Soxhlet extraction. No exhaustive release of non-extractable residues was achieved in radiotracer batch experiments.