Methodology for the exposure assessment of soil for organic chemicals. Part 1. Extraction procedure of non-volatile organic chemicals

A widely applicable clean-up scheme for the analysis of anthropogenic organic chemicals in soil, comparable to the "master-analytical-scheme" for organic compounds in water, is not available. Isotopically-labelled compounds representing seven classes of chemicals with a broad range of physico-chemical properties have been used to develop a general procedure for extraction, clean-up, and analysis. Two different soil-types have been spiked with these chemicals for at least four weeks prior to analysis. For non-volatiles, best results have been obtained by the extraction of soil by the system of water/dichloromethane resulting in a recovery of about 95%. For amines the recovery from aged residues is only 40%. A large amount of soil-borne impurities can be eliminated by subsequent gel chromatography, resulting in samples rady for further separation and quantification by HPLC, GC or for MS analysis.