高能偏振能量色散X射线荧光光谱仪测定地质样品中稀土元素

Determination of Rare Earth Elements in Geological Samples by High-Energy Polarized Energy-Dispersive X-Ray Fluorescence Spectrometry

由于稀土元素本身的特点及以往X射线荧光光谱仪的局限性,用XRF方法快速测定地质样品中稀土元素一直是个难点。探讨了有效解决该问题的途径。采用粉末压片制样,应用Epsilon 5型高能偏振X射线荧光光谱仪(HE-P-EDXRF)建立了土壤、岩石和水系沉积物中稀土元素La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu和Y的EDXRF分析方法,对分析线,二次靶,基体校正方法及校准曲线的回归等进行了探讨。结果表明,La,Ce,Pr,Nd和Y的校准曲线的相关系数r>0.99,其余元素的相关系数也均在0.969以上;Pr的检出限为4.09,其余元素的检出限在0.03~2.13之间;对岩石标准物质GBW07105连续测定10次,RSD在0.81%~8.35%;检验样本的EDXRF测定值与电感耦合等离子体质谱法(ICP-MS)测定值平均相对偏差在4.4%~15.4%之间,除Gd外其余元素的平均相对偏差均在15%以内,其中较好的为Y(4.4%),La(8.3%),Ce(8.3%),Nd(8.6%)。综上可知,本方法操作简单,能够实现大批量的岩石、土壤、水系沉积物中稀土元素的快速准确测定。

Rapid determination of rare earth elements（REEs）in geological samples based on X-ray Fluorescence Spectrometry（XRF）is always a difficulty because of the characteristics of the rare earth elements and the limitations of traditional X-ray fluorescence spectrometer.To sovle this problom,a rapid simultaneous multi-element analysis for La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu and Y in soil,rock and deposit has been established using High-Eenrgy Polarized Energy-Dispersive X-ray Fluorescence Spectrometer（HE-P-EDXRF）.The pressed powder pellet technique was adoped because of its simple sample preparation.Fifty-nine reference samples were used for the calibration.The measureing conditions of target elements were discussed,including the selection of analytical line and secondary target,matrix effect and spectral overlapping interence of some elements.The correlation coefficients of the linear regression lines for La,Ce,Pr,Nd and Ywere 0.99,and the rest were0.969.Detection limits for Pr were 4.09 ppm and 0.03~2.13 ppm for the rest.The rock composition standard material GBW07105 was detected for 10 replicate measurements,and the relative standard deviations（RSD）was 0.81%~8.35%.The average relative error of test set between EDXRF data and ICP-MS data was 4.4%~15.4%.In a word,this method could achieve accurate determination of rare earth elements in rock,soil and deposit rapidly,and it is simple in operation.