氢化物发生-原子吸收光谱法测定土壤中铅

土壤样品经HCl-HNO₃处理后，在盐酸介质中用铁氰化钾为氧化剂将Pb²⁺氧化为Pb⁴⁺，然后在盐酸浓度为5%(V/V)的载液中，以硼氢化钾为还原剂，采用氢化物发生-原子吸收光谱法测定了铅的含量。结果表明，在选定的实验条件下，铅量在0.5～60ng/mL范围内线性关系良好，方法检出限为0.24ng/mL。方法用于土壤标准物质中铅含量的测定，测定值与认定值相符，相对标准偏差(n=5)为1.8%～4.5%。对实际样品进行加标回收试验，回收率为92%～97%。

Determination of lead in soil by hydride generation-atomic absorption spectrometry

After treating the soil sample with HCl-HNO₃, Pb²⁺ was oxidized to Pb⁴⁺ in hydrochloric acid medium with potassium ferricyanide as oxidizing agent. Then, the content of lead was determined by hydride generation-atomic absorption spectrometry with potassium borohydride as reducing agent in 5% (V/V) hydrochloric acid carrier liquid. Under the selected experimental conditions, the results showed that the content of lead showed good linearity in range of 0.5-60 ng/mL. The detection limit of the method was 0.24 ng/mL. The proposed method was applied to determination of lead content in soil certified reference material. The results were consistent with the certified values. The relative standard deviations (RSD, n=5) were 1.8%-4.5%. The recovery test of actual sample was performed, and the recoveries were between 92% and 97%.