AFS Determination of Arsenic in Chinese Traditional Medicines

AFS was applied to the determination of arsenic in Chinese traditional medicines. The sample was digested with HNO3 under pressure (for total As), and extracted with HCl (1+1) at 60 ℃ (for inorganic As). Thiourea solution was added to the sample solution as pre-reductant and KBH4 solution as reductant. Flow-rates of 400 mL·min-1 for carrier gas and 900 mL·min-1 for shielding gas were taken in the analysis. Linear relationship between values of fluorescence intensity and mass concentration of As(Ⅲ) found was in the range within 80.0 μg·L-1, with detection limit (3s/k) of 31 ng·L-1. The proposed method was applied to the analysis of samples of Chinese traditional medicines. Values of total As found were in the range of 139-372 ng·g-1 and of inorganic As in the range of 41-103 ng·g-1. Values of recovery found were in the ranges of 89.0%-93.3% for total As and 86.0%-92.0% for inorganic As.