Studies on the determination of trace amounts of gold by chemical vapour generation non-dispersive atomic fluorescence spectrometry

Abstract

Volatile species of Au in 0.72 mol l⁻¹ HCl medium were generated at room temperature by reduction with 0.65% (m/v) KBH₄ using a programmable intermittent flow reactor and the detection system was used for the determination of trace amounts of gold by atomic fluorescence spectrometry. It was found that the presence of micro-amounts of DDTC greatly enhanced the generation efficiency of the volatile species and the flow rates of carrier and shield gas had a significant impact on the signal intensity of Au. In addition, high surface/volume ratio and rapid gas–liquid separation are essential for the generation of the volatile gold species. Based upon the results of the investigation, a detection limit of 0.23 ng ml⁻¹ was obtained under optimized conditions and the precision of the measurements for 20 ng ml⁻¹ of Au was 1.7% RSD. The method was successfully applied to the determination of gold in geological certified reference materials: the results were found to be in reasonable agreement with the certified values.