Selective determination of alkylmercury compounds in solid matrices after subcritical water extraction, followed by solid-phase microextraction and GC-MS

A method for the extraction and determination of methylmercury (MeHg) in so lid matrices is presented. Combining the advantages of two extraction techn iques-subcritical water extraction (subWE) and solid-phase microextraction (SPME)-selective separation of MeHg from soils is possible. The procedure i s based on extraction,vith subcritical water without using organic solvents , followed by irt situ aqueous-phase derivatization with sodium tetraethylb orate and headspace SPME with a silica fiber coated with poly(dimethylsilox ane), The optimization of the extraction parameters is described. The ident ification and quantification of the extracted alkylmercury compounds from s piked soil samples is performed by GC-MS after thermal desorption. Copyrigh t (C) 2000 John Wiley & Sons, Ltd.