QUALITY-CONTROL OF A RECENTLY DEVELOPED ANALYTICAL METHOD FOR THE SIMULTANEOUS DETERMINATION OF METHYLMERCURY AND INORGANIC MERCURY IN ENVIRONMENTAL AND BIOLOGICAL SAMPLES

A recently developed method for the simultaneous determination of methylmercury and inorganic mercury based on extraction, butylation, capillary gas chromatographic separation and atomic emission detection has been evaluated with respect to analytical quality. A number of reference and candidate reference materials have been analysed within international intercalibration exercises showing good agreement with respect to methylmercury and total mercury. Other small scale laboratory intercomparisons have also been made in order to assess the analytical performance. The materials analysed have a wide range of mercury concentrations from low ng g-1 to mug g-1. Finally, important characteristics such as artifact formation, detector selectivity, chromatographic performance and stability of mercury compounds during acid leaching, extraction and derivatization are discussed.