Routine lead isotope determinations using a lead-207–lead-204 double spike: a long-term assessment of analytical precision and accuracy

Abstract

Lead-isotope data obtained on a multicollector mass spectrometer over a four year period using a ²⁰⁷Pb–²⁰⁴Pb double spike to correct for the effects of mass discrimination, are reported. Considerable improvements in both precision and accuracy over conventional correction procedures were noted, without recourse to rigorous loading or run conditions. An external precision in ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb ratios ±0.003, 0.003 and 0.01 (2 × standard deviation), respectively, is routinely obtainable independent of minor variations in loading and run parameters.