便携式XRF测定仪在土壤检测中的应用及其影响因素

研究了便携式X射线荧光光谱仪(PXRF)的仪器性能,评估了其检出限、准确度及精密度,并和常规实验室检测方法比对进一步评估其性能,分析两者间的相关性和差异性。进一步探究了影响PXRF测定的2个最主要因素(土壤含水量和粒径)。结果表明:PXRF具备良好的仪器性能,8种元素的检出限为0.62～8.01 mg/kg,除Cd和Hg外,精密度均低于7%,准确度范围为-7.5%～11.1%。Pb、Cr、Cu、Zn、Ni、As的PXRF测定值与常规实验室方法测定值有良好的相关性,特别是Cu、Zn,相关系数可达0.873、0.832,而Cd和Hg的相关性则较弱。土壤含水量和土壤粒径会影响PXRF的测定性能,鲜样测定检测值普遍小于干样,0.15、2 mm粒径下检测值具有较强的相关性。研究旨在为PXRF的现场应用提供 参考,该方法可应用于初步监测和应急监测,实现土壤重金属元素的快速测定。

Application of Portable XRF Analyzer in Soil Detection and Its Influencing Factors

The instrument performance of portable X-ray fluorescence spectrometer (PXRF) was studied,and the detection limits,precision and accuracy were assessed in this paper. PXRF were compared with the conventional laboratory detection methods by analyzing their correlation and difference to further evaluate its performance. The results showed that PXRF had a good instrument performance, the detection limits of 8 elements were 0.62-8.01mg/kg, except for Cd and Hg, the precision was within 7%, and the accuracy ranged from -7.5% to 11.1%. The PXRF measured values of Pb, Cr, Cu, Zn, Ni, and As had a good correlation with the measured values of conventional laboratory methods, especially for Cu and Zn, the correlation coefficients were 0.873 and 0.832, respectively, while the correlation between Cd and Hg was weak. Soil moisture content and soil particle size affected the performance of PXRF measurements, the detection value under the fresh sample was generally smaller than that of the dry sample, and the detection value at 0.15mm and 2mm particle size had strong correlation. The study was aimed to provide a theoretical basis for the field application of PXRF, which can be applied to preliminary monitoring and emergency monitoring to achieve rapid determination of heavy metal elements in soil.