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

The determination of lead isotope ratios and concentrations in open an d coastal sea-water by a combination of chelating resin (Chelex-100) p reconcentration and inductively coupled plasma mass spectrometry is de scribed. The Pb-206:Pb-204, Pb-208:204, Pb-207:Pb-208 and Pb-206:Pb-20 7 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 T echnology (NIST) Standard Reference Material (SRM) 981 Lead, Common Is otopic, and compared with those in other work. The results revealed th at the proposed method was applicable to the measurement of lead isoto pe ratios in sea-water with precision adequate to be able to discuss t he origin of lead. The detection limit was 0.8 ng l-1.