中草药样品经硝酸-过氧化氢消化处理后,在酸性条件下用铁氰化钾将铅(Ⅱ)氧化为铅(Ⅳ),然后再以硼氢化钾为还原剂,盐酸为载流,用流动注射-氢化物发生-原子吸收光谱法测定铅含量。铅的质量浓度在0.50~20 μg·L-1范围内与其吸光度呈线性关系,检出限(3S/N)为0.067 μg·L-1。用此方法分析了4种中草药样品,铅测定值的相对标准偏差(n=5)在3.2%~4.8%之间,加标回收率在95.6%~103%之间。

Sample of Chinese herbal medicine was digested with HNO3-H2O2 and oxidized by K3Fe(CN)6, to transform Pb(Ⅱ) into Pb(Ⅳ). Lead was then determined by flow injection-hydride generation-atomic absorption spectroscopy (FI-HG-AAS) with KBH4 as reducing reagent and HCl as carrying solution. Linear relationship between values of absorbance and mass concentration of lead were obtained in the range of 0.50-20 μg·L-1, with detection limit (3S/N) of 0.067 μg·L-1. Four samples of Chinese herbal medicines were analyzed by the proposed method, values of RSD′s (n=5) obtained were in the range of 3.2%-4.8%, and values of recovery found by standard addition method were in the range of 95.6%-103%.