A NEW METHOD FOR EXTRACTING AND PURIFYING LEAD FROM DIFFICULT MATRICES FOR ISOTOPIC ANALYSIS

A new low blank separation scheme for lead is presented for the prepar ation of ultrapure lead samples for isotopic analysis by thermal ionis ation mass spectrometry. The method benefits from the selectivity and high capacity of a new extraction chromatographic material: Sr.Spec(TM ). The use of this material in HCl media, rather than the more usual H NO3 media, affords a straightforward separation of Pb from complex met al ores with high yield, good purity and satisfactory blank levels on very small (0.1 ml) columns using small volumes of solutions of a sing le mineral acid. It has the advantages that it also separates Pb from Bi in the same column that separates Pb from matrix elements and that, unlike other low blank methods for Pb, it is directly applicable to t he separation of traces of Pb from tin metal samples.