Determination of Lead Isotope Ratios of Tobacco by ICP-MS and Their Areal Difference

The lead isotope ratios of 100 B1F tobacco samples from 100 areas of 10 provinces in China were determined by ICP-MS combining with HNO₃-H₂O₂ microwave digestion and standard-sample-bracketing method.The results showed that the relative standard deviations of ²⁰⁷Pb/²⁰⁶Pb and ²⁰⁸Pb/²⁰⁶Pb for short-term measurements were 0.08% and 0.09%,respectively.The optimal concentration range of sample was from10 to 50 μg/L.The difference of lead isotope ratios between samples from the same province was relatively narrower,while that between samples from different provinces was obviously wider.The isotope ratios,²⁰⁷Pb/²⁰⁶Pb and ²⁰⁸Pb/²⁰⁶Pb,of tobacco sample could be used for comparing areal difference.