绿茶、红茶和咖啡中几种功能成分的分离鉴定及抗氧化性能的比较

用高效液相色谱－质谱联用分析法（HPLC／MS）分离鉴定了绿茶、红茶和咖啡中的主要活性化合物，如酚类（儿茶素、绿原酸等）、生物碱类（咖啡因等），并对上述饮品中的咖啡因含量进行了定量分析．实验表明：进样量20μL，流速200μL·min^-1条件下，用流动相乙腈／0．1％三氟乙酸进行梯度洗脱，能有效分离相关组分；各饮品中咖啡因的含量依次为绿茶〉咖啡〉红茶．同时用TEAC法测定和比较了各饮料样品的总抗氧化能力．

Functional Components and Antioxidant Value in Green Tea, Black Tea and Coffee

The separation and identification of the main active compositions in the common beverages （green and black tea, coffee） are achieved for analyzing the antioxidant activities using HPLC/MS, including the phenolic compounds （Catechines, Chlorogenic acid, etc.）, the purine alkaloids （Caffeine etc.）. The caffeine level is analyzed quantitatively in these given beverages using HPLC. The chromatographic parameters are optimized. The sampling volume is 20 μL. The flow rate is 200 μL·min^-1. The mobile phase of acetonitrile solution 0.1% trifluoro acetic acid is used to carry out gradient elution. The caffeine level found in these beverages can be placed in descending order as follows： green tea〉coffee〉black tea. Moreover, the antioxidant capacity is evaluated using the method of TEAC for comparing the overall antioxidant capacity among these common beverages.