Resolution Method of Overlapping Peaks in Soil XRF Spectrum Based on WPS-GMM
LI Tang-hu2, GAN Ting-ting1, 4*, ZHAO Nan-jing1, 2, 3, 4, 5*, YIN Gao-fang1, 4, 5, WANG Ying1, 3, 4, LI Xing-chi1, 3, 4, SHENG Ruo-yu1, 3, 4, YE Zi-qi1, 3, 4
1. Key Laboratory of Environmental Optics and Technology, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
2. Institute of Physical Science and Information Technology, Anhui University, Hefei 230601, China
3. University of Science and Technology of China, Hefei 230026, China
4. Key Laboratory of Optical Monitoring Technology for the Environment of Anhui Province, Hefei 230031, China
5. Institute of Environment Hefei Comprehensive National Science Center, Hefei 230031, China
Abstract：X-ray fluorescence (XRF) spectroscopy is an important technique for rapid and on-site detection of heavy metals. However, when it is used for detecting heavy metals in soil, due to the variety of elements contained in soil, there are some overlapping peaks in the soil XRF spectrum, which affects the accuracy of characteristic peak extraction and quantitative analysis of heavy metals. For this problem, this paper proposed a method for resolving the overlapping peaks in soil XRF spectra based on wavelet peak sharpening and Gaussian mixture model (WPS-GMM). This method first sharpened the overlapping peaks by a discrete wavelet transform to enhance the important local features of the spectral signal and clarify the peak positions of subpeaks. Then, using it as a prior constraint, a Gaussian mixture model of the overlapping peak was constructed. Finally, the relevant information for each subpeak in the overlapping peak was obtained by maximizing the likelihood to estimate the model parameters, thereby achieving the resolution of the overlapping peak. The established WPS-GMM method was applied to the resolution of typical overlapping peaks of Ni Kα-Co Kβ, Cu Kα-Ni Kβ, and Zn Kα-Cu Kβ in soil XRF spectra, as well as the quantitative analysis of Ni, Cu, and Zn corresponding to the main peaks in the overlapping peaks, to verify it saccuracy by comparing with the traditional resolution method for overlapping peaks based solely on the Gaussian mixture model (GMM). The results showed that compared with the GMM method, when the established WPS-GMM method was used for resolving the three overlapping peaks in soil XRF spectra, for the sub peaks of Ni Kα, Ni Kβ, Cu Kα, Cu Kβ and Zn Kα, the accuracy of resolved peak position increased by an average of 77.55%, 47.03%, 52.65%, 22.07%, and 8.43%, respectively, and the accuracy of resolved integral area increased by an average of 74.05%, 80.17%, 61.62%, 28.29%, and 43.59%, respectively; Moreover, the accuracy of quantitative analysis of Ni, Cu and Zn increased by an average of 73.23%, 68.47% and 47.62%, respectively. The established method demonstrated better universality for the accurate quantitative analysis of Ni, Cu, and Zn in soils with three different uses, including industrial, agricultural, and construction, by resolving the overlapping peaks in XRF spectra. Therefore, the established WPS-GMM method can more accurately obtain sub-peak information of overlapping peaks in XRF spectra of different soils, which is more conducive to improving the accuracy of quantitative analysis of heavy metals in soils by XRF. This study will provide an important methodological foundation for the rapid and accurate on-site detection of heavy metals in soil using XRF spectroscopy.
Key words：X-ray fluorescence; Resolution of overlapping peak; Heavy metal detection; Soil; Spectral analysis
李唐虎，甘婷婷，赵南京，殷高方，汪 颖，李星池，盛若愚，叶紫琪. 基于WPS-GMM的土壤XRF光谱重叠峰解析方法研究[J]. 光谱学与光谱分析, 2025, 45(10): 2737-2746.
LI Tang-hu, GAN Ting-ting, ZHAO Nan-jing, YIN Gao-fang, WANG Ying, LI Xing-chi, SHENG Ruo-yu, YE Zi-qi. Resolution Method of Overlapping Peaks in Soil XRF Spectrum Based on WPS-GMM. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2025, 45(10): 2737-2746.
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