采用氢化物发生-原子荧光光谱法测定茶水中砷含量。样品经硝酸-高氯酸(4+1)混合酸消解,在盐酸(6+94)溶液中加入30 g·L-1硼氢化钾-5 g·L-1氢氧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400 mL·min-1。试样溶液中加入硫脲及抗坏血酸混合溶液作为预还原剂。引入仪器的进取样量为1.2 mL,按选定的工作条件操作。荧光强度与砷的质量浓度在0.20~100 μg·L-1范围内呈线性关系,方法的检出限(3s/k)为0.030 μg·L-1。应用此法对3种茶叶泡出的茶水进行分析,测得回收率在97.7%~101.5%之间。

HG-AFS was applied to the determination of arsenic in tea. Sample was digested with mixed acid of HNO3-HClO4(4+1). Hydride of As(Ⅲ) were generated from HCl (6+94) solution by using solution of 30 g·L-1 KBH4 in 5 g·L-1 KOH solution as reducing reagent. Flow-rate of 400 mL·min-1 for the carrier gas was taken in the analysis. Mixed solution of thiourea and ascorbic acid was added to the sample solution as pre-reductant. An aliquot of 1.2 mL of the sample solution was introduced and operated under the prescribed working condition of the instrument. Linear relationship between the fluorescence intensity and mass concentration of As was found in the range of 0.20-100 μg·L-1, with detection limit (3s/k) of 0.030 μg·L-1. The proposed method was applied to the analysis of sample solutions extracted from 3 varieties of tea, giving values of recovery ranged from 97.7% to 101.5%.