DISTILLATION, ONLINE RP C18 PRECONCENTRATION AND HPLC-UV-PCO-CVAAS ASA NEW COMBINATION FOR THE DETERMINATION OF METHYLMERCURY IN SEDIMENTSAND FISH TISSUE

Distillation as a way of sample digestion has been combined with on-li ne RP C18 preconcentration and HPLC-UV-PCO-CVAAS (high performance liq uid chromatography - ultra violet - post column oxidation-cold vapour atomic absorption spectrometry) for the determination of methylmercury at background levels in sediments, soils and fish tissue. To prove th e accuracy of this method, it was applied to sediment and fish tissue reference materials. The results correspond with the reference values within their error ranges. Excellent recoveries (92-95%) were obtained for the sediment samples by means of the standard addition method. Th e standard deviations of the sediment samples were within an acceptabl e range (7.2-12.5%), those of the fish samples were substantially lowe r (3.4-5.0%). The detection limit is 0.04 ng/g for 1 g sample weight.