High-Precision Lead Isotope Ratio Coupled Plasma Multiple Collector Measurement by Inductively Mass Spectrometry

An inductively coupled plasma (ICP) ion source coupled to a magnetic sector mass analyser equipped with seven Faraday detectors has been used to measure the lead isotope ratios in solutions of Sanshiro Pond sediment collected at the University of Tokyo, airborne particulates collected at Shinjuku in Tokyo and Merck multielement s andard product number 97279494. A thallium correction technique was utilised to allow a simultaneous correction for mass bias. This work followed an earlier interlaboratory comparison study of the above-mentioned solutions using ICP quadrupole mass spectrometry, and has demonstrated a considerable improvement in analytical precision. The following isotope ratio measurements were recorded. Pond sediment solution containing 82 ng ml- ' lead: 206pb/2o4pb=17.762±0.014; 2 6Pb