微波消解-毛细管电泳法测定茶叶中的生物碱

Determination of Alkaloid in Tea by Microwave Digestion-Capillary Electrophoresis

应用微波消解-毛细管电泳法测定3种茶叶中的咖啡因、腺嘌呤及儿茶素类化合物。优化了缓冲溶液体系、浓度、pH及分离电压等实验条件。在最佳实验条件下,以30mmol/L硼砂-10mmol/Lβ-环糊精为缓冲溶液,pH为9.0,分离电压为22kV,检测波长为280nm,电动进样20kV×5s时,在7min内同时分离测定了咖啡因、腺嘌呤、儿茶素、表儿茶素、表没食子儿茶素没食子酸酯、抗坏血酸。各组分在0.5～100μg/mL范围内呈线性关系、检出限的范围是0.167～0.67μg/mL。3种茶叶中咖啡因、腺嘌呤、儿茶素、表儿茶素4组分的定量结果分别在741.4～878.2μg/mL、57.50～108.3μg/mL、104.9～192.6μg/mL、81.07～94.70μg/mL范围内,加标回收率的范围为86.55%～105.01%。

Caffeine,adenine and catechins in three different kinds of tea have been determined by microwave digestion-capillary electrophoresis. The optimum conditions were as follows：30 mmol/L sodium tertreborate running buffer containing 10 mmol/L β-cyclodextrin（pH=9.0）,separation voltage of 22 kV;UV detection at 280 nm,and injection at 20 kV for 5 s. Caffeine,adenine,catechin,epicatechin,epigallocatechin gallate and ascorbic acid were simultaneously analyzed within 7 min under the optimum conditions.The linear ranges of all compounds were within 0.5～100 μg/mL with the detection limits from 0.167 to 0.67 μg/mL.The contents of caffeine,adenine,catechin and EC in 3 kinds of tea were 741.4～878.2 μg/mL,57.50～108.3 μg/mL,104.9～192.6 μg/mL and 81.07～94.70 μg/mL,respectively,and the range of recoveries was 86.55%～105.01%.