偏振能量色散X-射线荧光光谱法测定土壤中Ni、Cu、Zn、Pb四种重金属元素

Heavy Metal Determination of Soil Samples by Polarized Energy Dispersive X-ray Fluorescence Spectrometry

以土壤和水系沉积物标准物质为校准样品,采用粉末样品压片制样,建立了偏振能量色散X-射线荧光光谱仪测定土壤中Ni、Cu、Zn、Pb四种重金属元素的方法。该方法分别采用Ge,Zn,Zr等3个不同二次靶对被分析元素进行选择性激发和测定,利用经验系数和康普顿散射线作内标校正基体效应,优化了元素校准曲线方程,实验结果表明,土壤和水系沉积物标准物质准确度实验结果符合定值要求,方法精密度RSD在1.12%～6.09%之间(n=10),Ni、Cu、Zn、Pb四种重金属元素的检出限分别达到2.54、0.93、0.96、0.98 mg/kg。土壤样品测定值与原子吸收法测定结果一致,该方法准确度、精密度、检出限均能满足土壤检测的需要。

A method for direct determination of Ni、Cu、Zn and Pb in soil and the stream sediment by polarized energy dispersive X-ray fluorescence spectrometry was developed,this method used certified soil and the stream sediment as standard materials and prepared by pressed powder pellet.The effect of matrix was corrected by experience coefficients and using Compton scattered radiation of the characteristic line of the secondary target as internal standard.The polarized targets（secondary targets） Zr,Zn and Ge were used for the excitation and determination of different elements and optimized the element standard curve equation.The method has been applied to the determination of Ni,Cu,Zn and Pb in standard reference materials.The results are in agreement with certified values with precision of 1.12% ～ 6.09%（n = 10）.On this analytical condition,the detection limits of Ni,Cu,Zn and Pb were 2.54,0.93,0.96,0.98 mg /kg and the measured results were in good agreement with those obtained by chemical method.The detection accuracies,precisions and limits of this method can meet the requirements of heavy metal determination in soil.