Application of ICP-MS to the analysis of lead isotope ratios in an ancient bronze mirror

The 207Pb/206 Pb and 208Pb/206Pb ratios in ancient bronze mirrors were measured using ICP-MS. The sample solution for ICP-MS was prepared by dissolving the mirror rust in a mixture of hydrochloric and nitric acid. ICP-MS analyses of the sample solution were repeated 10 times under adequate conditions, in the range of the relative standard deviation of 0.20.4% for 207Pb/206Pb and 208Pb/206 Pb ratios. In addition, the simultaneous analysis of standard solution enabled us to normalize the isotope ratios in a bronze mirror to the NIST standard. From the analytical results, the raw materials of two ancient mirrors, which had been excavated from the northern part of Kyushu island, were considered to have originated either in China after the Eastern Han dynasty, or the Korean peninsula.