AFS Determination of Mercury in Arsenic Ingot

A method of AFS for the determination of mercury in arsenic ingot was proposed. The sample was dissolved in mixed acid of HCl-HNO3 (1+1), and Hg(Ⅱ) in the sample solution was extracted into n-butyl alcohol. Mercury(Ⅱ) in the organic phase was reduced to mercury vapor with 10 g·L-1 potassium borohydride solution and determined by AFS. Linear relationship between values of fluorescence intensity and mass concentration of mercury was kept in the range of 0.15-80 μg·L-1, with detection limit (3s/k) of 0.20 μg·L-1. The proposed method was applied to the analysis of 2 samples of arsenic ingots, giving values of RSD′s (n=6) less than 2%, and values of recovery found by standard addition method in the range of 96.3%-97.2%.