中文摘要：

采用分步取样法验证便携式X射线荧光光谱仪的实验室异位检测法的实用性,以ICP-AES法为基准,对土壤重金属Cr、Cu、As、Pb的含量进行测定,试验中选用70%土壤样品建立一元线性校准模型,30%土壤样品进行校准模型的验证。结果表明,便携式X射线荧光光谱仪实验室异位检测法的检出限分别为Cr 17.7 mg/kg,Cu 10.4 mg/kg,As 5.4 mg/kg,Pb 6.2 mg/kg,均低于国家土壤环境质量一级标准。对国内外标准物质进行多次重复测定,RPD在–8.9%~7.9%,说明仪器在异位测定重金属含量时具有较好的精密度与准确度。分析PXRF法与传统方法测定建立的拟合方程,其决定系数分别为0.817 3、0.787 0、0.673 3和0.722 1,表明PXRF室内异位法可用于土壤重金属Cr、Cu、As、Pb的快速测定;二次采样建立的验证模型R2分别为0.912 4、0.897 9、0.772 3、0.872 9,逐渐靠近理想模型,充分验证PXRF异位法的实用性和校准曲线的准确性,可适用于农田土壤Cr、Cu、As、Pb的快速测定、污染筛查,为土壤重金属速效测定提供有力依据;但仪器在异位测定As元素时准确性降低,建议异位测定时需进行数据校准。

英文摘要：

The feasibility of the portable X-ray fluorescence（PXRF） spectrometer in ex-situ measuring soil heavy metals in the laboratory was determined by comparison of the traditional ICP-AES method. 70% of soil samples were used to establish the linear calibration models of soil Cr, Cu, As and Pb concentrations and the remaining 30% of soil samples were used to validate the established calibration models. The results showed that the detection limits of PXRF were 17.7 mg/kg for Cr, 10.4 mg/kg for Cu, 5.4 mg/kg for As, and 6.2 mg/kg for Pb, respectively, all are below the national 1st standards for soil environmental quality. The reference materials from China and abroad were measured iteratively, and the residual predictive deviation ranged from –8.9% to 7.9%, which indicated PXRF has better precision and accuracy in measuring soil heavy metal content. The R2 of the fitted curves between PXRF and ICP methods were 0.817 3, 0.787 0, 0.673 3 and 0.722 1, respectively, all reached the significant level, which suggested PXRF can ex-situ rapidly measure soil Cr, Cu, As and Pb contents in laboratory. The R2 values of calibration models established by resampling were 0.912 4 for Cr, 0.897 9 for Cu, 0.772 3 for As, and 0.872 9 for Pb, respectively, which were gradually close to the ideal models and fully validated the feasibility of PXRF and the accuracy of the calibration curves. In general, PXRF can ex-situ rapidly determining soil Cr, Cu, As an Pb as well as contamination screening. However, a calibration curve must be established when using PXRF in measuring soil As in the laboratory because of the lower of measure accuracy.