DETERMINATION OF LEAD ISOTOPE RATIOS AND CONCENTRATIONS IN SEA-WATER BY INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY AFTER PRECONCENTRATION USING CHELEX-100

The determination of lead isotope ratios and concentrations in open and coastal sea-water by a combination of chelating resin (Chelex-100) preconcentration and inductively coupled plasma mass spectrometry is described. The Pb-206:Pb-204, Pb-208:204, Pb-207:Pb-208 and Pb-206:Pb-207 isotope ratios were measured with relative standard deviations of 1.2, 0.9, 0.1 and 0.3%, respectively. The accuracy of the isotopic data was checked with reference materials, National Research Council Canada NASS-3 Open Ocean Sea-water and National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) 981 Lead, Common Isotopic, and compared with those in other work. The results revealed that the proposed method was applicable to the measurement of lead isotope ratios in sea-water with precision adequate to be able to discuss the origin of lead. The detection limit was 0.8 ng l-1.