We measure high-precision Pb isotope ratios using a mixed 204Pb-207Pb double spike. Pb isotope ratios for both spiked and unspiked sample aliquots are measured on single Re filaments with a silica gel – phosphoric acid emitter solution in a 3-sequence dynamic routine to eliminate detector efficiencies and amplifier gain corrections for the 207Pb/206Pb and 204Pb/206Pb ratios. The reproducibility of these ratios is routinely <30 and 100 ppm respectively. We are capable of measuring Pb isotopic compositions of a variety of rocks, minerals, and ores, as well as environmental and anthropogenic samples including waters, soils, paints and gasoline.
