中草药样品经硝酸-高氯酸-硫酸消化处理后,在酸性条件下用硫脲和抗坏血酸将砷(Ⅴ)还原为砷(Ⅲ),然后再以硼氢化钾为还原剂,稀盐酸为载液,用流动注射氢化物发生原子吸收光谱法测定砷含量.砷的质量浓度在1.6~32.0 μg·L-1范围内与其吸光度呈线性关系,检出限(3s/k)为0.32 μg·L-1.用此方法分析了3种草药样品,砷的测定值的相对标准偏差(n=6)在5.1%~8.1%之间,加标回收率在91.4%~106.1%之间.

Chinese herbal medicine sample was digested with HNO3-HClO4-H2SO4 and reduced by thiourea and ascorbic acid,to transform As(Ⅴ) to As(Ⅲ).Arsenic was then determined by flow injection-hydride generation-atomic absorption spectroscopy (FI-HG-AAS) with KBH4 as reducing reagent and dilute HCl as carrying solution.Linear relationship between values of absorbance and mass concentration of arsenic was obtained in the range of 1.6-32.0 μg·L-1,with detection limit (3s/k) of 0.32 μg·L-1.Three samples of Chinese herbal medicines were analyzed by the proposed method,values of RSD′s (n=6) obtained were in the range of 5.1%-8.1%,and values of recovery found by standard addition method were in the range of 91.4%-106.1%.