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奶粉中的重金属污染物是影响奶粉食用安全的主要因素之一,其快速检测具有重要的意义.本论文尝试采用激光诱导击穿光谱(LIBS)检测奶粉中的Cu元素含量,根据不同Cu元素含量的LIBS光谱结果,获得元素质量分数与谱线强度的关系曲线.为了进一步提升LIBS光谱的检测限及定量精度,采用迭代小波变换(IWT)算法同时克服光谱噪音及背景干扰.计算结果表明,IWT算法显著提升了LIBS光谱定量分析的预测精度,将奶粉中Cu元素的检测限从0.501×10~(-6)降低到0.273×10~(-6),为奶粉中重金属含量的快速检测提供了一种有效手段.
The heavy metal pollutants in milk powder is one of the main factors that affect the food safety of milk powder, and its rapid detection is of great significance.In this paper, the content of Cu in milk powder is determined by laser induced breakdown spectroscopy (LIBS) LIBS spectra were obtained to obtain the relationship between elemental mass fraction and spectral line intensity.In order to further improve the detection limit and quantitative accuracy of LIBS spectra, the iterative wavelet transform (IWT) algorithm was used to overcome the spectral noise and background interference simultaneously.The calculated results show that the IWT The proposed method significantly improves the prediction accuracy of LIBS quantitative analysis. The detection limit of Cu in milk powder is reduced from 0.501 × 10 -6 to 0.273 × 10 -6, providing a rapid detection of heavy metals in milk powder An effective means.