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
DU Zhenyu1,2, CAO Guan1,2, YAO Zhixiao1,2, LI Siming1,2, ZHANG Hui1,2, LI Yuwu*1
1. National Research Center for Environmental Analysis and Measurements,Beijing 100029,China; 2. Key Laboratory of Dioxin Pollution Control for Ministry of Ecology and Environment,Beijing 100029,China
Abstract：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.
杜祯宇, 曹冠, 姚志枭, 李斯明, 张辉, 李玉武. 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[J]. 冶金分析, 2024, 44(10): 79-86.
DU Zhenyu, CAO Guan, YAO Zhixiao, LI Siming, ZHANG Hui, LI Yuwu. 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. , 2024, 44(10): 79-86.
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