改进X荧光光谱仪快速检测土壤中重金属

针对传统能量色散X荧光仪(energy dispersive X-ray fluorescence，EDXRF)分析土壤中微量重金属测量精确度低的问题，提出了一种X荧光仪改进方法。为了减少反射X射线的影响，入射X射线垂直照射样品，探测器平行放置与样品一侧且垂直于X射线。样品与探测器之间由准直器连接。对国家标样测量结果表明，仪器对Mo，Zn，Cu，Pb，Zr，Nb的检出限为0.4，6.68，1.97，6.84，1.60，7.59 mg·kg-1。各元素对数偏差在0～0.05之间。元素含量在三倍检出限以上RSD%(GBW)小于7，元素含量在三倍检出限内RSD%(GBW)小于15。为了验证改进后X荧光仪测量效果，在大兴安岭地区采集土壤样品与传统荧光仪进行比较分析。改进X荧光仪提高了土壤中微量重金属测量精度，满足野外地质普查要求。

Study on Heavy Metal Detection in Soil with Improved EDXRF

Due to the low precision and accuracy of trace heavy metals detection wiith traditional energy disper-sive X-ray fluorescence (EDXRF)system,an improved EDXRF system is proposed.In order to reduce the in-fluence of reflected rays,the sample is irradiated with the incident X-rays vertically,and the detector is placed in parallel with the sample’s section.The sample is connected with detector through collimator.With im-proved EDXRF measures certified reference materials,the results show that the detection limit of the improved EDXRF system for Mo,Zn,Cu,Pb,Zr,Nb is 0.4,6.68,1.97,6.84,1.60,7.59 mg·kg-1 respectively and the logarithm deviation of each element in the standard samples is between 0 and 0.05.The RSD%(GBW) is less than 7 as the element content is more than three times of the detection limit,and it is below 1 5 when the element content is less than three times of the detection limit.The soil samples collected from Da Xing’an Ling region are applied to verify the improved EDXRF system.The proposed EDXRF system can improve the meas-urement accuracy of trace heavy metal detection in soil,satisfying the requirements of geologic exploration.