微波消解-动态三磁场塞曼背景校正石墨炉原子吸收法测定土壤中铅

目的 建立微波消解-动态三磁场塞曼背景校正石墨炉原子吸收法测定土壤中铅的分析方法。方法 样品除杂过筛研磨后，经微波消解，加基体改进剂磷酸氢二铵，在动态三磁场背景校正模式下进行测定。结果 标准曲线浓度范围为0 μg/L～500 μg/L，其中0 μg/L～50 μg/L浓度范围采用二磁场背景校正模式，标准曲线方程为A = 4.64×10-3C + 3.22×10-4，r = 0.9964,特征浓度0.94 μg/L；50 μg/L～500 μg/L浓度范围采用三磁场背景校正模式，标准曲线方程为A=(1.80×10-2 +1.77×10-3C)/(1+9.81×10-4C)， r = 0.9970，特征浓度 2.49 μg/L，样品加标回收率为96.9%～104.4%，RSD为2.4%～4.2%。结论 本法准确、灵敏，线性范围宽，可应用于土壤中铅的测定。

Determination of lead in soil by GFAAS with microwave digestion-dynamic tri-magnetic field Zeeman background correction

Objective This work was to establish a method for the determination of lead in soil by GFAAS with dynamic tri-magnetic field Zeeman background correction. Methods After sieved and ground，soil samples was digested by microwave, and finally measured with diammonium hydrogen phosphate as matrix modifier. Results The linear range of the method was 0 μg/L~500μg/L. When the concentration range was 0 μg/L~50μg/L, bi-magneticfiled background correction mode was used with the correlation equation of A=4.64×10-3C+3.22×10-4 （r=0.9964） and the characteristic concentration of 0.94μg/L. When the concentration was 50μg/L-500μg/L , tri-magnetic field background correction mode was applied and the correlation equation was A=(1.80×10-2 +1.77×10-3C)/(1+9.81×10-4C) (r= 0.9970). The corresponding characteristic concentration was 2.49 μg/L. The recovery of the method was 96.9%-104.4%, with RSDs of 2.4%-4.2%. Conclusion This method is accurate, sensitive, and has much wider linear range. It can be applied to the determination of lead in soil.