Determination of Trace Gold in Geochemical Samples by Graphite Furnace Atomic Absorption Spectrometry with Polyurethane Foam Preconcentration under Hypobaric Hypoxia Condition

In order to determine trace gold in geochemical samples by GF-AAS under hypobaric hypoxia condition in Tibetan areas, the effects of digestion solvents, adsorption temperature, desorption time and dosage of Fe³⁺on the determination were discussed. GF-AAS measurement condition was optimized and the catalytic mechanism of Fe³⁺ during sample processing and pre-concentration steps was studied in detail. The detection limit of the method for Au was 0.102 ng/g with dynamic range of 0.24~300 ng/g. The accuracy of the method was 0.01~0.03 (ΔlgC,n=12) with precision of 1.61%~7.33%RSD (n=12). The method has been applied to the determination of trace gold in geochemical samples in Tibetan with satisfactory results.