微波消解-氢化物发生-原子荧光光谱法测定中药材中痕量砷

采用微波消解法用硝酸-过氧化氢(3+1)溶液消解样品,以硫脲及抗坏血酸混合溶液作为预还原剂,利用氢化物发生-原子荧光光谱法测定中药材当归、丹参、甘草、三七和黄芪中痕量砷的含量。在盐酸(3+97)溶液中加入溶于20g.L-1氢氧化钾溶液中的10g.L-1硼氢化钾溶液使与溶液中砷离子反应生成氢化物。分析中采用载气流量为800mL.min-1。砷的质量浓度在12μg.L-1以内与其对应的荧光强度呈线性关系,方法的检出限(3s/k)为0.020μg.L-1。应用此法对国家标准物质人发(GBW 09101)进行分析,测定值与认定值一致。

HG-AFS Determination of Trace Amount of Arsenic in Traditional Chinese Medicines with Microwave Assisted Sample Digestion

HG-AFS was applied to the determination of trace amounts of arsenic in traditional Chinese medicine(TCM),including angelica,salvia,liquorice,panax and astragalus.Samples of TCM was digested with mixed solution of HNO3-H2O2(3+1),and the mixture of thiourea and ascorbic acid was added to the sample solution as pre-reductant.Hydrides of As(Ⅲ) were generated from HCl(3+97) solution by reacting with 10 g·L-1 KBH4 solution(dissolved in 20 g·L-1 KOH solution).Flow-rates of 800 mL·min-1 for carrier gas and 800 mL·min-1 for shielding gas were taken in the analysis.Linear relationship between the fluorescence intensity and mass concentration of As found was in the range within 12 μg·L-1,with detection limit(3s/k) of 0.020 μg·L-1.The proposed method was applied to the analysis of hair(GBW 09101),the results obtained were in conformity with the certified values.