Accelerated solvent extraction method for the determination of polychlorinated biphenyls and organochlorine pesticides in soil

This paper describes a fast and simple method for the determination of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in soil samples using accelerated solvent extraction (ASE). Spiked soil samples were extracted by ASE using a mixture of hexane/acetone (3/1, v/v). The extracts were cleaned on silica impregnated with concentrated sulfuric acid and the final analysis was performed with GC-ECD and GC-MS. The accuracy of the method was assessed through analysis of a certified reference material (CRM-481) contaminated with PCBs. The method limits of quantification ranged between 0.1 - 1.8 ng/g soil and were dependent on the levels of analytes in the procedural blanks. The average recoveries of OCPs and PCBs in spiked soil (range 66 - 149%) were considered satisfactory. The procedure was applied to 18 soil samples from Moldavia province in which DDT and analogues were the major contaminants.