Evaluating accuracy and inter-laboratory reproducibility of the compositional analysis of ancient bronzes

Chemical analysis is fundamental for archaeometric study of ancient Chinese bronzes. A large corpus of compositional data on ancient bronzes has been acquired through various modern analytical instruments. However, the accuracy and reproducibility of the data have not been systematically evaluated. This renders much difficulty for the comparative study of chemical results from different laboratories. Our research evaluated the accuracy and reproducibility of the analytical data of several laboratories in China based on 10 bronze reference materials. We found that the results were fine for Cu, Sn, Fe, and Ni but relatively poor for Pb, Sb, Bi, Ag, Zn, Co, As, Mn, Al, and Cd. We also examined data distribution from multiple laboratories and analytical methods. Statistical analysis suggests that the results can be used to estimate data variation among different laboratories and that legacy data can be used in a more quantitative way.