HG-AFS Determination of Arsenic in Gold-Loaded Carbon

HG-AFS was applied to the determination of arsenic in gold-loaded carbon. Sample was dissolved with HNO3 and HClO4, and hydride of As(Ⅲ) was generated from HCl (10+90) solution by reacting with 20 g·L-1 KBH4 solution (dissolved in 5 g·L-1 KOH solution). Flow-rates of 300 mL·min-1 for carrier gas and 900 mL·min-1 for shielding gas were taken in the analysis. Mixed solution of thiourea and ascorbic acid was added to the water sample as reductant. One mL of sample solution was introduced and operated under the prescribed working condition of the instrument. Linear relationship between the fluorescence intensity and mass concentration of As(Ⅲ) was found in the range within 120 μg·L-1, with detection limit (3S/N) of 0.05 μg·L-1. Tests for precision were performed with 10 μg·L-1 and 80 μg·L-1 of As by addition of standard solution, values of RSD′s (n=11) found were 1.2% and 1.0% respectively. The proposed method was applied to the analysis of samples of gold-loaded carbon, giving values of recovery in the range of 92.8%-101.9%.