Philip Aruscavage 1976 <p><span>A rapid procedure is described for the determination of lead in rocks by an isotope-dilution substoichiometric method. After the sample has been digested with acid in the presence of&nbsp;</span>²¹⁰<span>Pb tracer, the lead is separated by dithizone extractions. After the lead has been back-extracted into aqueous solution, it is reacted with a substoichiometric amount of EDTA. Excess of unreacted lead is removed by extraction with dithizone in carbon tetrachloride, and the specific activity of the aqueous complex is determined by counting&nbsp;</span>²¹⁰<span>Pb. The standard deviation of the method is less than 10 % for replicate determinations of lead in several U.S. Geological Survey standard rocks. The agreement with literature values indicates that the method is accurate.</span></p> application/pdf 10.1016/S0003-2670(01)84612-2 en Elsevier Determination of lead in rocks by radiometric isotope dilution and substoichiometric extraction article