氢化物发生-原子吸收光谱法测定中药中砷(Ⅲ)和砷(Ⅴ)

Speciation Analysis of Arsenic in Traditional Chinese Medicines by Hydride Generation-Atomic Absorption Spectrometry

本文用氢化物发生(HG) 原子吸收光谱法(AAS)测定中药中的三价砷及五价砷。在pH5.6～6.0时,砷(Ⅲ)与硼氢化钾作用生成气态氢化物,而砷(Ⅴ)不发生反应;在2mol/L盐酸溶液中,用硫脲和抗坏血酸还原砷(Ⅴ)为砷(Ⅲ),同法测总砷,用差减法求得砷(Ⅴ)含量。方法检出限为7.5μg/L,RSD为1.45%。回收率为89.2%～114.6%。利用本方法成功地对六种中成药中的砷进行了形态分析。

A method for the determination of arsenic species (As(Ⅲ) and As(Ⅴ)) in Traditional Chinese Medicine by hydride generation-atomic absorption spectrometry (HG-AAS) has been studied. As(Ⅲ) can be determined directly using HG-AAS in a medium with pH of 5.6～6.0, and the total content of As can be analyzed with the reduction of As(Ⅴ) to As(Ⅲ) in a medium of 2 mol/L HCl. The content of As(Ⅴ) was obtained by their difference. The experimental conditions that influence the signal intensity of As and the reduction of As(Ⅴ) were investigated and optimized, and the effects of foreign ions and their elimination were studied. The proposed method was applied to the determination of arsenic species in six kinds of Traditional Chinese Medicine. The detection limit and relative standard deviation of the method were 7.5 μg/L and 1.45%, respectively, and the recoveries were in the range of 89.2%～114.6%.