Application of Isotope Dilution Mass Spectrometry for Reference Measurements of Cadmium. Copper, Mercury, Lead, Zinc and Methyl Mercury in Marine Sediment Sample

Marine sediment was selected as a test sample for the laboratory inter-comparison studies organized by the Environment Laboratoryes of the International Atomic Energy. The analytical procedure to establish the reference values for the Cd, Cu, Hg, Methyl Hg, Pb and Zn amount contents was based on Isotope Dilution Inductively Coupled Plasma-Mass Spectrometry (ID ICP-MS applied as a primary method of measurement..The Hg and Methyl Hg determination will be detailed more specifically because of the problems encountered with this element, including sample homogeneity issues, memory effects and possible matrix effects during the ICP- MS measurement stage. Reference values, traceable to the SI, with total uncertainties of less than 2% relative expanded uncertainty (k=2) were obtained for Cd, Cu, Zn and Pb and around 5% for Hg and CH 3 Hg.