基于THz时域光谱技术的水果杀菌剂农药检测与鉴别

摘要

利用太赫兹时域光谱技术对3种水果样品及其与杀菌剂农药混合的样品分别进行THz光谱测试,获得它们在0.2～1.5 THz波段的THz时域数据,计算它们的折射率和吸收系数谱.提取其特征THz吸收光谱,分析水果与噻菌灵样品在不同农药含量条件下吸收系数的变化规律.结果表明:THz吸收谱中吸收峰的位置和幅值随样品种类和含量不同存在差别;为提高光谱的区分度,将3种水果样品的THz吸收光谱的一阶导数作为分类特征数据,用主成分方法(Principal Component Analysis,PCA)进行鉴别,样品类别鉴别正确率可达100％.%Three kinds of fruits (banana, mango, orange) and triabendazole mixtures were measured by terahertz time-domain spectroscopy (THz-TDS) to obtain their terahertz spectrum in the frequency range 0.2-1.5 THz. The absorption coefficient and refractive index of samples were calculated. The spectroscopy characteristics in THz wave range were presented. Terahertz spectroscopy variation rules of different content of fruits and thiabendazole were concluded. The experimental results show that the absorption spectrum features of samples are different. According to the cluster analysis result using the derivative absorption spectra of three kinds of samples as feature vector for principal component analysis (PCA) , the rate of correct classification of mixture of fruit and bactericide is nearly 100%.