三维荧光光谱技术及平行因子分析法在绿茶分析及种类鉴别中的应用

Three-Dimensional Fluorescence Spectroscopy Combined with Parallel Factor Analysis as a Complementary Technique for Green Tea Characterization

提出了一种绿茶成分分析和种类鉴别的新方法。利用FS920荧光光谱仪测量得到国内生产的26个绿茶样品的三维荧光光谱矩阵(EEMs),建立了不同种类绿茶在特定范围内(激发波长为300～550 nm,发射波长为310～750 nm)的三维荧光光谱图和等高线光谱图。采用平行因子分析法(PARAFAC)计算得到绿茶的3因子激发-发射光谱轮廓图和样品因子投影得分图。通过因子光谱特征分析确定绿茶的三种主要成分(茶多酚、黄酮醇及叶绿素);通过三维荧光光谱图和等高线光谱图的图谱特征和样品因子投影得分图的分析,证实三维荧光光谱技术和平行因子分析法对绿茶进行成分分析和种类鉴别,是一种高效、精确的方法。

This paper proposes a new method for analyzing and characterizing green teas. The excitation emission fluorescence matrixs （EEMs） of twenty-six types of green teas were measured with FS920 fluorescence spectrometer. The three-dimensional （3D） spectra and contour maps were obtained by measuring the emission spectra in the range from 310 nm to 750 nm, and excitation wavelengths from 300 nm to 550 nm. The excitation and emission profiles of three factors were plotted from parallel factor analysis （PARAFAC） model. The spectra characters of three main components （tea polyphenols, flavonol, chlorophyll） in green teas were ascertained. Different green teas can be characterized and distinguished with the sample projection plots of the PARAFAC model. The results demonstrate the capability of the combination of 3D fluorescence spectra technology and three-factor PARAFAC model for characterizing, differentiating and analyzing green teas.