Precise lead isotope ratios in Australian galena samples by high resolution inductively coupled plasma mass spectrometry

Abstract

High resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) was used to measure Pb isotope ratios in standard solutions and Pb mineral digests. The RSD values obtained for 208Pb/204Pb, 207Pb/204Pb, 206Pb/204Pb, 208Pb/206Pb and 207Pb/206Pb were 0.13, 0.11, 0.11, 0.046 and 0.048%, respectively (values as 1 [lowercase sigma]). These values were obtained from 30 analyses of three different standard sample types (multi-element standard, NIST SRM 981 and a Broken Hill galena digest). Based on 39 analyses of 11 galena samples from different locations around Australia, the difference between HR-ICP-MS and conventional TIMS values for 208Pb/204Pb, 207Pb/204Pb, 206Pb/204Pb, 208Pb/206Pb and 207Pb/206Pb ratios was generally better than +/- 0.2%. This paper outlines a very simple and rapid analytical method for the measurement of Pb isotope ratios, and is one of the first studies to use HR-ICP-MS to measure Pb isotope ratios in galena and galena-bearing ores.