Homogeneity Test for Samples with High-content of Gold

15 samples, named “HACEAu-1”, with high-content of gold were digested with aqua regia and the residues were decomposed with HFHClO4. Gold in the sample solution was preconcentrated by activated carbon adsorption and determined by FAAS. Duplicate analysis for 15 samples was carried out and the measurement uncertainty for the analytical results was evaluated. The main sources of measurement uncertainty came from subuncertainties of the analytical balance, scale accuracy of the analytical glassware, gold adsorption rate by activated carbon. The composed uncertainty was calculated with a range of 2.5% to 4.2%, which means that the method was feasible. The reliability for the results from duplicate analysis of single sample and the limiting error of its arithmetic mean value were also evaluated. The homogeneity quality coefficient of the sample was calculated as 0.70, which means that the sample was in “good” homogeneity quality grade.