Determination of copper, cadmium and lead in biological samples by isotope dilution inductively coupled plasma mass spectrometry after on-line pre-treatment by anodic stripping voltammetry

Flow injection isotope dilution ICP-MS was applied to the determination of Cu, Cd and Pb in several biological samples after on-line pre-treatment by anodic stripping voltammetry. The isotope ratios for each injection were calculated from the areas of the flow injection peaks. The influence of the operating conditions of the electrochemical system on the analyte signals was studied. The influence of non-spectroscopic and spectroscopic interferences caused by the matrix on the precision and accuracy of isotope ratio determinations was also investigated. The precision for isotope ratio determinations was better than 2%. Detection limits were 0.07, 0.01 and 0.07 ng ml–1 for Cu, Cd and Pb, respectively. The isotope dilution ICP-MS method was successfully applied to the determination of Cu, Cd and Pb in National Research Council of Canada CRMs DORM-1 Dogfish Muscle and DOLT-1 Dogfish Liver and NIST SRM 2670 Toxic Metals in Freeze-Dried Urine.