J. Biochem. Biophys. Methods 43 (2000) 403–409 www.elsevier.com / locate / jbbm Use of supercritical fluid extraction in the analysis of pesticides in soil 1 2 * ¨ Robert Kreuzig , Andrea Koinecke , Mufit Bahadir Institute of Ecological Chemistry and Waste Analysis, Technical University of Braunschweig, Hagenring 30, D-38106 Braunschweig, Germany Abstract 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 was a time-saving extraction procedure which reduced solvent usage and solvent waste, SFE 2 efficiency proved only competitive to conventional slurry and Soxhlet extraction. No exhaustive release of non-extractable residues was achieved in radiotracer batch experiments.  2000 Elsevier Science B.V. All rights reserved. Keywords: SFE; Pesticides; Soil; Residue analysis; Radiotracer analysis; Non-extractable residues 1. Introduction Residue analyses of pesticides in soil samples are usually performed employing multimethods like DFG S19 [1]. According to the original version of this method, target compounds are extracted by slurry extraction with an acetone–water mixture followed *Corresponding author. E-mail address: r.kreuzig@tu-bs.de (R. Kreuzig) 1 Present address: Federal Biological Research Centre for Agriculture and Forestry, Chemical Division, Messeweg 11–12, D-38104 Braunschweig, Germany. 2 www.tu-bs.de / institute / oekochem / oekochem.html 0165-022X / 00 / $ – see front matter  2000 Elsevier Science B.V. All rights reserved. PII: S0165-022X(00)00056-7