用逐步回归分析法和单元素轮换优化法筛选土壤和沉积物样品ED-XRF经验系数法校准模型中基体元素  

Selection of matrix elements in ED-XRF calibration model of empirical coefficient method for soil and sediment samples by stepwise regression analysis and single element rotation optimization method

作　　者：杜祯宇 曹冠 姚志枭 李斯明[1,2] 张辉 李玉武[1] DU Zhenyu;CAO Guan;YAO Zhixiao;LI Siming;ZHANG Hui;LI Yuwu(National Research Center for Environmental Analysis and Measurements,Beijing 100029,China;Key Laboratory of Dioxin Pollution Control for Ministry of Ecology and Environment,Beijing 100029,China)

机构地区：[1]国家环境分析测试中心,北京100029 [2]生态环境部二恶英污染控制重点实验室,北京100029

出　　处：《冶金分析》2024年第10期79-86,共8页Metallurgical Analysis

基　　金：国家重点研发计划(2022YFC3700500);生态环境部标准制修订项目(2021-21)。

摘　　要：能量色散X射线荧光光谱法(ED-XRF)在环境监测领域用于测定土壤、沉积物样品中重金属元素日益普及。经验系数法是校准模型中最常使用的方法。如果校准模型中基体元素数量过多,不合适的组合会导致校准模型产生“过拟合”现象。即校准曲线拟合质量很好,但用于实际样品测试时,分析误差明显高于模型建立时拟合结果,不符合质控要求。采用逐步回归分析法和单元素轮换优化法筛选基体元素,可以快速得到满足质控指标的基体元素组合。采用4家ED-XRF实验室土壤样品元素实测数据验证了计算过程。研究结果表明,基体元素筛选结果与校准曲线中的标准样品有关。不同标准样品构成的校准曲线可能对应不同筛选结果;相同标准样品在不同实验室测量数据,基体元素筛选结果不一定相同。讨论了方法使用中的注意事项。此方法同样适合于波长色散X射线荧光光谱(WD-XRF)经验系数法校准模型中基体元素的筛选。Energy dispersive X-ray fluorescence spectrometry(ED-XRF)is increasingly popular in the field of environmental monitoring for the determination of heavy metals in soil and sediment samples.The empirical coefficient method is the most commonly used in the calibration model.If the quantity of matrix elements in calibration model is excessive,the improper combination will lead to the phenomenon of"over-fitting"in the calibration model.In other words,the fitting quality of calibration curve is very good,but when it is used in actual sample testing,the analysis error is obviously higher than the fitting result when the model is established,which does not meet the quality control requirements in routine analysis.In this study,the matrix elements were selected by stepwise regression analysis and single element rotation method,and the matrix element combination that met the quality control index could be obtained quickly.The calculation process was verified by the measured data of soil and sediment samples from four ED-XRF laboratories.The results showed that the screening results of matrix elements were related to the certified reference materials(CRMs)in the calibration curve.The calibration curves composed of different CRMs may correspond to different screening results.The screening results of matrix elements were not necessarily the same when the same CRM was measured in different laboratories.Matters needing attention in the use of these two methods were discussed.The proposed method was also suitable for the selection of matrix elements in the wavelength dispersive X-ray fluorescence spectrometry(WD-XRF)calibration model of empirical coefficient method.

关 键 词：经验系数法 能量色散X射线荧光光谱法(ED-XRF) 逐步回归分析法 单元素轮换优化法 土壤 沉积物 重金属测定 

分 类 号：O657.34[理学—分析化学]