HG-AFS Determination of Trace Amounts of Antimony in Traditional Chinese Medicines

HG-AFS was applied to the determination of trace amounts of antimony in traditional Chinese medicines (TCM).Sample of TCM was soaked in conc.HNO3 overnight,and then digested in a microwave oven with supplementary addition of H2O2.A solution of L-cysteine was added to the sample solution as reductant and masking agent.Working condition of the instrument and factors influential to fluorescence intensity,i.e.,acidity of sample solution and carrier solution,and amount of potassium borohydride added,were studied and optimized.Linear relationship between values of fluorescence intensity and concentration of antimony was obtained within 10 μg·L-1.Detection limit (3S/N) of the method found was 0.0384 μg·L-1.Test for precision was made by analyzing 2 TCM samples with 5 determination for each sample,giving average value of antimony 0.083 and 0.038 μg·g-1,and values of RSD′s 3.69% and 4.12% respectively.Test for recovery was made by adding standard Sb(Ⅲ) solution to samples with known Sb content,and values of recovery obtained were 96.0%.Twelve kinds of TCM samples were analyzed for antimony content by the proposed method.