INSITU EXTRACTION AND DERIVATIZATION OF PENTACHLOROPHENOL AND RELATED-COMPOUNDS FROM SOILS USING A SUPERCRITICAL FLUID EXTRACTION SYSTEM

An in situ supercritical fluid extraction and derivatization procedure for the determination of pentachlorophenol (PCP) and related compounds from soil samples is described. Phenols are extracted from soil and acetylated in situ with supercritical carbon dioxide in the presence of triethylamine and acetic anhydride at a temperature of 80-degrees-C. Quantitative recovery of di-, tri-, tetra- and penta-chlorophenols was obtained by a 10-min extraction with carbon dioxide at 37.2 MPa (365 bar, 0.8 g/ml density) from soil samples fortified to 0.5 and 5-mu-g/g levels. In a comparison study, the supercritical fluid extracton and the steam distillation methods both produced very similar results for pentachlorophenol and other chlorophenols in a reference sample. When this method is applied to contaminated soils samples collected in a wood treatment plant, results for chlorophenols in a sample can be obtained in approximately 90 min.