原子荧光光谱法同时测定食品及环境样品中的镉和汞

Simultaneous Determination of Cadmium and Mercury in Food and Environmental Samples by Atomic Fluorescence Spectrometry

目的 建立原子荧光光谱同时测定食品和环境样品中镉和汞的方法.方法 湿法消解样品,在最佳仪器条件下同时测定样品的镉和汞.结果 挥发性物质产生反应的条件:酸度0.24 mol/L HCl,硫氰酸钾及抗坏血酸浓度分别为10 g/L,硼氢化钠溶液浓度20 g/L.精密度:测定2 ng/ml的镉、汞混合标准溶液,其相对标准偏差镉2.4%～5.7%之间、汞3.2%～6.5%之间;试样相对标准偏差分别为镉1.9%、汞2.8%.镉、汞标准在0～4 ng/ml范围,其相关系数分别为0.999 8、0.999 6.检出限:镉0.003 1ng/ml、汞0.003 6ng/ml.样品加标回收率:镉95.0%～102.0%、汞94.0%～99.0%.结论 该法具有操作简单、快速,干扰少,准确度、灵敏度高等优点,适用于食品及环境样品中的镉和汞的同时测定.

Objective To establish a method for synchronizing determination of cadmium and mercury in food and environmental samples by Atomic Fluorescence Spectrometry. Methods Food and environmental samples were digested by wet method. Cadmium and mercury in samples were determined simultaneously under the best instrument condition. Results The reaction medium condition for volatile substances: acidity 0.24 mol/L HCl,concentration of KSCN and VitC 10 g/L,NaBH_4 20 g/L.Precision: The RSD of mixing standard solution for cadmium and mercury at 2 ng/ml were 2.4%-5.7% for cadmium and 3.2%-6.5% for mercury,respectively. The RSD of samples were 1.9% for cadmium and 2.8% for mercury. The linear calibration curves for cadmium and mercury were both within the range of 0-4ng/ml and their correlative coefficients were 0.999 8 and 0.999 6 ,respectively. The detection limits were 0.003 1 ng/ml for cadmium and 0.003 6 ng/ml for mercury. The standard recovery rates of spiked samples were from 95.0% to 102.0% for cadmium and from 94.0% to 99.0% for mercury. Conclusions The method is simple,rapid,specific,accurate and sensitive. It can be adopted for simultaneous determination of cadmium and mercury in food and environmental samples.