茶叶活性成分的荧光性质与分析方法研究.pdf

河北师范大学
硕士学位论文
茶叶活性成分的荧光性质与分析方法研究
姓名:徐玉春
申请学位级别:硕士
专业:分析化学
指导教师:魏永巨
20100508
摘要
研究了儿茶素和表儿茶素的荧光光谱性质,考察了实验条件对其荧光光谱的影响。
对西湖龙井茶和苦丁茶进行了荧光光谱的分析研究,建立了测定茶叶中儿茶素和表儿茶
素的新方法。利用柱色谱分离出两种色素物质,它们在 365 nm 紫外灯下均显红色荧光。
论文工作主要包括三部分:
1、研究了儿茶素和表儿茶素的内源荧光和敏化荧光性质,探讨了溶液酸度、有机
溶剂、金属离子、表面活性剂 SDS 和ß-CD 对荧光光谱的影响。儿茶素水溶液在酸性条
件下有稳定的荧光,最大激发和发射波长分别为 280 nm 和 311 nm。5<pH<9 时,随 pH
升高荧光减弱,pH>9 时,由于酚羟基质子的电离而使荧光消失。以 L-色氨酸为参比,
测得儿茶素和表儿茶素的荧光量子产率分别为 和 。同时对茶叶中的咖啡碱和
茶碱的荧光光谱性质进行了初步的考察,发现二者自身均不发荧光。
2、研究了 21 种茶叶水浸液的三维荧光光谱,发现它们的图谱在短波处都有荧光峰
出现,并且光谱基本相似。详细研究了两种茶叶水浸液的荧光光谱性质,佐证了茶叶中
的主要成分为儿茶素类。此外,在选好的实验条件下,两种茶叶稀溶液中所含荧光组分
的荧光强度都与其浓度呈良好的线性关系,据此可以对茶叶中的荧光组分进行定量分
析。
3、用高效液相色谱法/荧光检测法对茶叶中儿茶素和表儿茶素同时进行定量分析,
建立了选择性测定药材中二者含量的新方法。
4、采用柱色谱方法对茶叶中色素类进行分离,得到两种在硅胶板上发红色荧光的
物质,研究了其三维荧光图谱,测量了 1H-NMR 图谱、13C-NMR 图谱、红外吸收光谱
和质谱,推测了其结构特征。

关键词:荧光光谱;儿茶素;表儿茶素;茶叶;柱色谱;荧光量子产率;高效液相
色谱




I
Abstact
In this thesis, fluorescence properties of (+)-Catechin (C) and (-)-Epicatechin (EC) were
studied. Influence of experimental conditions on fluorescence spectroscopy was inspected.
The fluorescence spectra of West Lake Longjing tea and Kuding tea were studied. Two kinds
of pigments with red color when irradiated with 365nm UV-irradiation were separated by
column chromatography.
The main contents of the thesis were as follows:
1. The native fluorescence and sensitized fluorescence properties of C and EC were
impacts of acidity, organic solvents, metal ions, surface active agent (SDS and
ß-CD) on fluorescence spectroscopy were inspected. Under acidic conditions, catechins
solution had a stable fluorescence. The maximum excitation and emission wavelengths were
280 nm and 311 nm. As the acidity of solution changes from pH 5 to pH 9, fluorescence
decreases. When pH greater than 9, flurescence disearpered due to phenolic hydroxyl proton
ionization. Using L-tryptophan as a reference, fluorescence quantum yields of C and EC were
determined to be and 0