GFAAS Determination of Platinum, Palladium, Rhodium and Iridium in Ores

Platinum, palladium, rhodium and iridium in ore samples were enriched by the lead fire assaying method, and the alloy of precious metals obtained was dissolved in HNO3 and HCl. The contents of Pt, Pd, Rh and Ir in the sample solution were determined by GFAAS. It was found that under the optimum working conditions of the graphite furnace, linear relationships between values of absorbance and mass concentration were obtained in the ranges of 20-150 μg·L-1 for Pt, 15-120 μg·L-1 for Pd, 6-100 μg·L-1 for Rh and Ir. Detection limits (3s/k) found were 4.6 μg·L-1 (Pt), 4.0 μg·L-1 (Pd) and 1.5 μg·L-1 (Rh and Ir). The proposed method was used in the analysis of 2 ore CRM′s (GBW 07341, GBW 07342) and the results obtained were in conformity with the certified values. Values of recovery found by standard addition method were in the range of 87.6%-105.5%. Values of intra-day and inter-day RSD′s (n=7) found were in the ranges of 2.8%-3.6% and 3.5%-4.7% respectively.