微波消解—石墨炉原子吸收法在土壤铅、镉含量分析中的应用

Determination of lead and cadmium in the soils by graphite furnace atomic absorption spectrometry with microwave digestion

对WT50,GSS-2和GSS-12等3个土壤样品分别采用湿法消解和微波消解,各消解液分别选用两种基体改进剂用石墨炉原子吸收法测定土壤Pb,Cd含量。结果表明,经微波消解的土壤样品测定结果的准确度与精确度均优于湿法消解;采用5%磷酸氢二铵基体改进剂测定土壤Pb含量比采用0.06%硝酸镁+0.1%磷酸二氢铵混合液基体改进剂的测定结果更接近土壤成分分析标准物质标准值,而土壤Cd含量则是混合基体改进剂比单一基体改进剂的测定结果更接近土壤成分分析标准物质标准值。

The digestion solutions of three kinds of soil samples i. e. WT50, GSS-2 and GSS-12 were prepared by wet digestion and microwave digestion methods for measuring the contents of Pb and Cd, respectively. Then, the concentrations of Pb and Cd in digestion solutions were determined by graphite furnace-atomic absorption spectrometry with two modified matrices. The one modified matrix was 5 % （NH4）2HPO4 and the other one was an admixture of 0.06 % Mg（NO3）2 and 0.1% NH4H2PO4. It was found that more exact and precision results were obtained by microwave digestion method compared with wet digestion method. Higher precision results were obtained when 5 % （NH4）2HPO4 was used as the matrix modifier to test Pb while 0.06% Mg（NO3）2 and 0.1% NH4H2PO4 was used as the matrix modified to test Cd.