【作者】 杨柳；

【导师】 董川；

【作者基本信息】 山西大学 ， 分析化学， 2005， 硕士

【摘要】 第一章 简要介绍了茶叶中多酚的发展状况和研究概况。总结了其理化性质、提取方法和分析方法,综述了茶多酚的生理活性及其在医药、食品等方面的广泛应用,指出研究茶多酚的简便、灵敏、快速的分析方法,对各种多酚产品中多酚含量的定性和定量分析具有重要的意义。 第二章:本文用分光光度法研究了饮茶过程中,冲泡水质、冲泡水温、冲泡时间、冲泡次数及冲泡比对茶多酚溶出的影响,并测定了隔夜茶中茶多酚含量的变化,从而对人们日常正确、合理、科学地饮茶提供了理论的依据。实验结果表明:冲泡茶叶的水最好为纯净水、冲泡比为1g/50mLH₂O、水温控制在96℃以上、冲泡时间20min以上、冲泡次数最多3次,隔夜茶中的茶多酚含量呈下降趋势。利用分光光度法与KMnO₄滴定法对不同绿茶中茶多酚的含量进行测定,结果表明:两种方法之间存在较大的系统误差。 第三章:本文研究了茶多酚水溶液的紫外吸收光谱和荧光光谱特性。并考察了溶液酸度对它的两种光谱的波长和强度的影响。结果表明茶多酚在波长200～330 nm之间有较强的吸收,不同酸度条件下其吸收图谱有较大的变化,随着溶液pH值的升高,其最大吸收波长发生红移;茶多酚是一种弱的荧光物质,在一定的酸度范围内有较宽的发光范围,在酸性、中性及弱碱性条件下它的荧光强度相对较强,在强碱性介质中它的荧光被显著猝灭,同时,随着溶液pH值的增大,其荧光发射峰位置发生红移;表明在溶液的pH值不同时,它们的分子结构发生了变化。 第四章:在pH5.02的B-R缓冲溶液中茶多酚对水杨酸钠的荧光强度具有明显的猝灭作用,猝灭程度F/F’与加入的茶多酚浓度成线性关系,据此建立一种测定茶多酚含量的荧光猝灭分析方法。确定了最佳测定条件,得到测定茶多酚含量的线性回归方程为F/F’=0.9962+0.0126c（mg/L）,线性范围为2.5～50mg/L,r=0.9962,检出限为2.465mg/L;平均回收率为101.72%。对含量为0.01g/L的茶多酚标准溶液进行11次平行测定,其相对标准偏差为1.78%,并考察了干扰因素对测定的影响。结果更多还原

【Abstract】 Chapter 1: The general situations of research of tea polyphenols have been reviewed. Their chemical, physical properties, characteristics, methods of extraction and analysis of tea polyphenols were discussed and gave a detailed description of pharmacology and its application in medicament, food, etc. It is important to research tea polyphenols.Chapter 2: The method of spectrophotometer is applied for investigation on various factors affecting on lixiviating of tea polyphenols. Those factors include water quality, water temperature, infusing time, infusing frequency and infusing ratio. It is shown that the water should use the temperature should be higher than 96℃ and the time should be than 20 minutes, the infusing ratio should be lg/50mLH2O. The content of tea polyphenols in keeping-process of tea soup is decreasing.Chapter 3: Many researches on tea polyphenols have been developed in domestic, but most of them were related to its pharmacology. Papers on the fluorescence spectrum behavior are very few. The absorption and fluorescence luminescence spectra behavior of tea polyphenols have been studied in this paper. The effects of pH on their absorption and fluorescence spectra were exhaustively researched.Chapter 4: A new method for the determination of tea polyphenols (TP) with sodium salicylate ( SS) is described. The method is based on the fluorescence quenching effect of TP and SS in the buffer of Britton-Robision at pH 5.02. The best determination condition has been worked out. The linear equation of the fluorescence quenching is: F/F’=0.9962 +0.0126c (mg/L) (r=0.9962) . The linear range is 2.5-50 mg/L, the detection limit is 2.4650mg/L, and the mean recovery is 101.72%. The relative standard deviation for the measurement of 0.01g/L tea polyphenols (n=11) was 1.78%. The proposed method has been successfully applied to the determination of tea polyphenols in tea.更多还原