APPLICATION OF ICP-MS TO THE ANALYSIS OF LEAD-ISOTOPE RATIOS IN AN ANCIENT BRONZE MIRROR

The Pb-207/Pb-206 and Pb-208/Pb-206 ratios in ancient bronze mirrors w ere 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 u nder adequate conditions, in the range of the relative standard deviat ion of 0.2 similar to 0.4 % for Pb-207/Pb-206 and Pb-208/Pb-206 ratios . In addition, the simultaneous analysis of standard solution enabled us to normalize the isotope ratios in. a bronze mirror to the NIST sta ndard. From the analytical results, the raw materials of two ancient m irrors, which had been excavated from the northern part of Kyushu isla nd, were considered to have originated either in China after the Easte rn Han dynasty, or the Korean peninsula.