Determination of Gold in Geological Samples by Flow Injection- Flame Atomic Absorption Spectrometry

Sample was combusted at 650℃ for 1.5 h and then dissolved by aqua regia. Two blocks of polyurethane foam (1.5 cm×1.0 cm×1.0 cm) were used to adsorb and enrich ordinary level amount of gold in sample solution for two times. Gold was released from the foam by keeping the foam in sulfourea solution for 20 min in boiling water bath, and determined by FAAS. The working conditions of the instrument were studied and optimized. The detection limit of the method was 0.022 μg/g (DF=1). The detection limit (3σ) and measurement range were 0.022 μg/g and 0.05~60 μg/g, respectively.The reliability of the method has been tested by determination of gold in National Standard Reference samples and the results are in agreement with certified values with precision of less than 8.0%RSD (n=11).