原子荧光光谱法测定土壤与水中汞含量的参数优化

Determination of mercury in soil and water by atomic fluorescence spectrometry

本实验利用原子荧光光谱法测定土壤与水中的汞。通过对氢化物发生的条件,载气流速,雾化条件等,以及一些仪器的参数设置,通过改变单一变量的方法进行逐个研究。得出的最佳测定条件为:载液,5%盐酸;还原剂,硼氢化钠的含量10g/L;氩气流量,300mL/min;炉温,200℃;负高压,-280V;灯电流,40mA;炉高:9mm。在此条件下的检出限为0.028μg/L,低于标准中的0.04μg/L,回收率为97.1%~101.4%。以GSS-18号标准土为基准,对比硫酸-硝酸-高锰酸钾、微波消解和水浴消解三种不同方法对其消解后的测出值、RSD等参数。结论:这3种方法的检出值均符合要求,但水浴消解的方法更简单,测出标准土中汞含量的平均值为0.0155μg/g,RSD为4.9%,较好。

The optimal analysis conditions were as follows： Reactive acid was 5% HCl and 10g/L NaBH4 as deoxidizer;The gas flow of argon was set 300mL/min with atomizing temperature of 200℃and furnace height of 9mmThe negative high voltage was set -280V and light current 40mA;The detection limit of the method was 0. 028μg/L for mercury, lower than 0.04μg/L for that in the standard method. The recovery rate was 97.1%-101.2%. The detection values of standard soil GSS-18 and the RSDs were determined using three digestion method, i.e. H2SO4 --HNO3- KMnO4, microwave digestion and bath digestion. The results indicated all data were in accord with the requirements of standard material. However, water bath digestion was simpler than the other two methods and corresponding result was more accurate and reliable, i.e. mercury content of 0. 0155μg/g in soil with RSD of 4.9%.