GFAAS Determination of Trace Amount of Gold in Geochemical Exploration Sample

The geochemical exploration sample was combusted at 650 ℃ for 1.5 h and dissolved with HNO3-HCl(1+1).A block of polyurethane foaming plastic (3 cm×2 cm×1 cm) was used to adsorbed and enriched trace gold in sample solution.Gold(1) was released from foam plastic by keeping foam plastic in sulfourea solution for 20 min in boiling water bath,and determined by GFAAS.Influential factors,including the working conditions of graphite furnace-atomization and amount of ascorbic acid added as matrix modifier,were studied and optimized.Detection limit (3S/N) of the method was 0.06 ng·g-1.The proposed method was used in the analysis of 5 CRM′s,giving values of RSD′s (n=11) less than 6.0%.