中文摘要：

将基于在线高效液相色谱-二苯基三硝基苯肼（HPLC—DPPH＊）快速筛选自由基清除剂的方法与电喷雾飞行时间质谱（ESI—TOF／MS）结合，建立了茶叶粗提物中抗氧化活性成分在线筛选与鉴别的方法。本方法是在HPLC色谱柱分离后进行分流，一路进入ESI—TOF／MS用于各化合物的快速鉴别，另-路流出液与稳定的自由基DPPH＊混合，实现在线筛选自由基清除剂的作用。本方法用于茶水中抗氧化成分的快速筛选与鉴别，筛选出11个具有明显DPPH＊自由基清除作用的化合物，通过ESI—TOF／MS在线分析获得的质谱信息，结合相关文献和数据库，实现了各化合物的快速鉴别。11个化合物分别为茶氨酸、Theogallin、没食子儿茶素、茶碱、色氨酸、表没食子儿茶素、表没食子儿茶素没食子酸酯、表儿茶酚、没食子酸酯、没食子儿茶素没食子酸酯及儿茶素没食子酸酯。本方法效率高、稳定性好，是复杂天然产物中抗氧化剂快速筛选与鉴别的有力工具。

英文摘要：

A new method based on the HPLC on-line scavenging diphenyl-l-picrylhydrazyl（DPPH＊ ） radical activity and ESI-TOF/MS for the rapid screening and identification of radical scavengers from water extract of tea was developed. Water extract of tea was separated by HPLC. The outlet of HPLC flow cell was connected to a split valve in order to divert a flow to ESI-TOF/MS for on-line rapid identification of the antioxidants in water extract of tea, and another stream react post-column with the DPPH solution for on-line screening the antioxidants in water extract of tea. The results showed that eleven compounds in tea have scavenging radical activity, and all the eleven compounds including theanine, theogallin, gallocatechin grade, theophyline, tryp- tophan, epigallocatechin, epigallocatechin-3-gallate, table eatecholc, gallate, gallocatechin-3-gallate and catechin gallate were identified by ESI-TOF/MS according to literatures and data base. The method has also been used for several other natural products successfully. This method is reliable, efficient and it is a powerful tool for rapid screening and identification of free radical scavenging compounds in complex natural products.