Simultaneous determination of trace arsenic(III), antimony(III), total arsenic and antimony in Chinese medicinal herbs by hydride generation-double channel atomic fluorescence spectrometry

A new method was developed for simultaneous determination of trace arsenic and antimony in Chinese herbal medicines by hydride generation-double channel atomic fluorescence spectrometry with a Soxhlet extraction system and an n-octanol-water extraction system, respectively. The effects of analytical conditions on the fluorescence intensity were investigated and optimized. A water-dissolving and methanol-water-dissolving capability were compared. The contents of different species in five Chinese herbal medicines and their decoctions were analyzed. The concentration ratios of n-octanol-soluble As or Sb to water-soluble As or Sb were related to the kinds of medicine and the acidity of the decoction. Soxhlet extraction was found to be an effective method for plants pretreatment for determination of arsenic and antimony species in Chinese herbs; the interferences of coexisting ions were evaluated. The proposed method has the advantages of simple operation, high sensitivity and high speed, with 3(sigma) detection limits of 0.094 (mu)g g^-1 for As(III), 0.056 (mu)g g^-1 for total As, 0.063 (mu)g g^-1 for Sb(III) and 0.019 (mu)g g^-1 for total Sb in a 1.0 g of the sample.