GFAAS Determination of Trace Amounts of Au and Ag in Geochemical Sample

The geochemical sample was dissolved in mixed acid of HCl-HNO3-H2O(3+1+4). Trace amounts of Au and Ag in the sample solution were adsorbed on polyurethane foamed plastics which was adsorbed with diphenylthiourea prelimiarily and separated by elution with 10 g·L-1 thiourea solution from the foamed plastics. The solution obtained was used for determination of Au and Ag by GFAAS. Linear relationships between values of absorbance and mass concentration of Au and Ag were obtained in the ranges within 100.0 μg·L-1 and 200.0 μg·L-1 respectively, with detection limits (3s) of 0.3 ng for Au and 0.2 ng for Ag. The proposed method was used in the analysis of geochemical CRM′s, giving results in consistency with the certified values.