采用氢化物发生-四通道原子荧光光谱仪同时测定化探样品中砷、锑、铋和汞的含量。试样溶于盐酸-硝酸-水(3+1+4)的混合酸中,分取适量试液在盐酸(1+4)溶液和含硫脲10 g·L-1的介质中预还原30 min。用纯氩气作载气和屏蔽气,流量依次为300,900 mL·min-1。仪器采用间歇流动进样方式,硼氢化钾溶液的质量浓度为15 g·L-1。上述4种元素的质量浓度在一定范围内呈线性,检出限(3S/N)为0.031 μg·L-1(砷)、0.028 μg·L-1(锑)、0.024 μg·L-1(铋)和0.004 8 μg·L-1(汞)。应用此方法分析了化探样品,并用标准加入法对上述4种元素进行回收试验,测得回收率在95.4%~101%之间。

HG-AFS with 4 channels was applied to the determination of As, Sb, Bi and Hg in geological samples. The sample was dissolved with mixed acid solution of HCl-HNO3-H2O(3+1+4). An aliquot of the sample solution in HCl(1+4) medium was pre-reduced by reacting with thiourea (having its concentration attained to 10 g·L-1 in the solution) for 30 min. Pure argon was used both as carrying gas and shielding gas with their flow-rates at 300 mL·min-1 and 900 mL·min-1 respectively. Intermittent flow mode of sample introduction was adopted in the instrumental operation. Concentration of KBH4 used was 15 g·L-1. Linearities were attained for the 4 elements in definite ranges. Values of detection limits (3S/N) found were (μg·L-1) 0.031 (for As), 0.028 (for Sb), 0.024 (for Bi) and 0.004 8 (for Hg). The proposed method was used for analyzing a geological sample and recovery for the 4 elements was tested by standard addition method, results of recovery found were in the range of 95.4% to 101%.