| The gold content in iridium, osmium, ruthenium-doped gold jewelry is hard to determine by either density method or X-ray fluorescence. Samples were first digested with aqua regia in a high- pressure sealed container, then separated the doped insoluble metals by vacuum filtration. 80% hydrazine hydrate (diluted 10 times by water) was used as a reduction reagent to reduce the gold in the filtrate to precipitation. After filtering, washing and sintering, the gold content in samples was determined by gravimetric method, and the purity of gold was measured by spark source atomic emission spectrometry. The recovery rate of the gold was between 96.2% and 101.6%, and the relative standard deviation (RSD, n=6) was between 0.09% and 0.23%. The proposed method can be used for the determination of gold in iridium, osmium, ruthenium-doped gold jewelry. |
