HPLC法测定有机化学实验用4种茶中的咖啡因

Determine the extracting caffeine from four type teas by HPLC in organic chemistry experiment

目的 HPLC法测定学生有机化学实验用的四种茶叶中的咖啡因的含量。方法 4种茶叶分别用乙醇(95%)经索氏提取器提取,用HPLC法测定咖啡因含量后与学生实验结果进行比较。结果学生提取咖啡因含量:绿茶1为0.26%、绿茶2为0.29%、红茶为0.29%、砖茶为0.17%,HPLC测定结果:绿茶1为1.87%、绿茶2为2.73%、红茶为2.36%、砖茶为0.73%,提取率为10.62%～23.29%,绿茶2、红茶含量最高、砖茶含量较低,学生提取结果与HPLC法测定结果的结论一致。结论学生实验获得的咖啡因纯度较高,说明升华法是纯化咖啡因的有效方法,但提取率低。影响提取率的因素很多,标准规范的实验操作是学生实验提高收率的保证条件之一。

Objective To evaluate the caffeine content of extract from four type teas in student organic chemistry experiment.Methods The teas were extracted with ethanol（95%） by Soxhlet extractor.The content of caffeine was assayed by high performance liquid chromatography（HPLC）.Results The extraction ratio of the caffeine fulfilled by students are： green tea 1 has 0.26%,green tea 2 has 0.29%,black tea has 0.29% and brick tea has 0.17%.The content of the caffeine determined by HPLC are： green tea 1 has 1.87%,green tea 2 has 2.73%,black tea has 2.36% and brick tea has 73%.The extraction efficiency is 10.62%～23.29%.The caffeine in green tea 2 and black tea are higher and the content of caffeine in brick tea is lower.The extraction by students correspondence with the determination by HPLC.Conclusion The purity of caffeine extracted by student is higher.It is showed that the technology of organic solvent extract caffeine from tea is already well-provided.But the extraction efficiency is not high.There are many influencing factors,and the standard operate procedures are one of the guarantee to get higher yield.