Lead speciation in rainwater by isotope dilution-high performance liquid chromatography inductively coupled plasma mass spectrometry

A new method for lead speciation in rainwater by isotope dilution analysis (IDA) using directly coupled high performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) is described and demonstrated. Samples containing trimethyllead (TML) chloride and triethyllead (TEL) chloride in the presence of large amounts of inorganic lead have been analysed by HPLC-ICP-MS using reverse phase ion-pairing chromatography. The detection limit for the procedure is 3 ng g(-1) for TML as Pb and 14 ng g(-1) for TEL as Pb, with a linear range exceeding 1000 ng g(-1) and a relative standard deviation of 4% for TML in the range 50-1000 ng g(-1). TML chloride isotopically enriched in the stable 206 isotope was prepared and used to enhance the accuracy of the method by isotope dilution analysis. The IDA-HPLC-ICP-MS method was successfully applied to the analysis of a sample of artificial rainwater used in a collaborative study. (C) 1998 Elsevier Science B.V.