Determination of methylmercury in fish and aqueous samples using solid-phase microextraction followed by gas chromatography-atomic fluorescence spectrometry

An analytical method is described for methylmercury determination in fish and aqueous samples using solid-phase microextraction (SPME) followed by gas chromatography–atomic fluorescence spectrometry (GC–AFS). The procedure involves aqueous-phase derivatization of methylmercury species with sodium tetraethylborate in a sample vial and subsequent extraction with a silica fiber coated with poly-­(dimethylsiloxane). The mercury derivatives are desorbed in the splitless injection port of a gas chromatograph and subsequently analyzed by GC–AFS. The headspace SPME procedure is used and parameters affecting the extraction, adsorption and desorption are evaluated. Results for methylmercury analysis in standard reference material (DORM-2) and fish samples are presented.