石墨炉原子吸收光谱法测定土壤中镉

GFAAS Determination of Cadmium in Soil

土壤样品经盐酸、硝酸、高氯酸和氢氟酸加热消解,采用石墨炉原子吸收光谱法(GFAAS)测定其中镉的含量。10g·L^-1磷酸二氢铵溶液为基体改进剂,灰化温度为700℃、原子化温度为1 450℃。镉的质量浓度在0.2~1.6μg·L^-1内与其吸光度呈线性关系,检出限(3s)为0.008mg·kg^-1。对土壤标准物质进行12次测定,测定值的相对标准偏差(RSD)为4.1%~4.9%,相对误差(RE)为2.5%~4.7%。应用此方法分析了场地调查土壤样品,测定结果与电感耦合等离子体质谱法(ICP-MS)测定结果吻合。

The soil sample was digested and heated with a mixture of HCl,HNO3,HClO4 and HF,and the content of cadmium in sample solution was determined by GFAAS.The 10 g·L^-1 NH4H2PO4 solution was used as matrix modifier,and temperatures selected for ashing and atomization were 700℃ and 1 450℃ respectively.Linear relationship between values of absorbance and mass concentration of cadmium was obtained in the range of 0.2^-1.6μg·L^-1,with detection limit(3s)of 0.008 mg·kg-1.The soil reference materials were determined for 12 times,giving values of RSDs in the range of 4.1%-4.9% and RE in the range of 2.5%-4.7%,respectively.The proposed method was used in the analysis of site investigation soil sample,and the results were in good agreement with those obtained by inductively coupled plasma mass spectrometry(ICP-MS).