Single-stage method for the simultaneous isolation of lead and strontium from silicate samples for isotopic measurements

A new scheme for the simultaneous separation of lead and strontium is described and applied to the determination of isotope ratios in silicate samples. This method is based on the selectivity and high capacity of the extraction chromatographic material referred to as Sr.Spec. This new procedure affords a straightforward separation of Sr and Pb on 150µl columns, with high Pb yield (>96%), good purity and satisfactory blank levels, using small volumes of mineral acids (HNO3 and HCl) easy to purify by sub-boiling distillation. The degree of purity of the Sr and Pb separates was evaluated by ICP-MS measurements whereas the yields and blanks were determined by ID-TIMS. The validity of the method for isotopic analyses is illustrated by Sr and Pb isotopic compositions obtained on basaltic and trachy-andesitic rocks.