土壤中镉的分步消解-石墨炉原子吸收光谱测定法

Determination of cadmium in soil by step digestion-graphite furnace atomic absorption spectrometry

目的建立土壤中镉的分步消解-石墨炉原子吸收测定法。方法土壤先经氢氟酸消解除硅,赶酸近干后加入硝酸继续消解,消解液加入500 mg/L硝酸钯作为基体改进剂,灰化温度为450℃,进行石墨炉原子吸收光谱法测定。结果镉浓度在0.4~2.0μg/L范围内,所得回归方程为A=0.0483c+0.00349,呈良好的线性关系,r=0.9974。该方法的检出限为0.03μg/L,定量下限为0.09μg/L;回收率为92.5%~99.5%,RSD为1.5%~5.5%。结论该方法操作简单安全,消解彻底,试剂用量少,重现性好,适合批量不同类型土壤样品中镉的污染监测。

Objective To establish a step digestion-graphite furnace atomic absorption method for the determination of cadmium in soil.Methods Firstly,the silica in soil was removed by hydrofluoric acid,then nitric acid was added to continue to digest the soil when the acid was driven to nearly dry.The content of cadmium was determined by graphite furnace atomic absorption spectrometry,and 500 mg/L palladium nitrate was selected as the matrix modifier with the ashing temperature at 450℃.Results The regression equations A=0.0483c+0.00349 showed a good linearity for cadmium in the range of 0.4-2.0μg/L,and the coefficient of correlation was 0.9974,the limit of detection was 0.03μg/L,the limit of quantitation was 0.09μg/L,the recovery rates were in the range of 92.5%-99.5%,and the precision were 1.5%-5.5%.Conclusion This method is simple,accurate,with complete digestion and good repeatability,and is applicable to the determination of cadmium in different types of soil samples.