Microwave-Assisted Extraction and HPLC Determination of Catechins and Caffeine in Tea

Caffeine and 3 catechins in tea were separated by microwave-assisted extraction using ethyl acetate as solvent,and their contents were determined in the extract.The operating conditions of extraction were studied by using the method of orthogonal experimental designing and optimum conditions found were as follows:① temp.of extraction:100 ℃;② time of extraction:10 min;③ extraction solvent:mixture of ethyl acetate and water (mixed in the ratio of 1 to 8).Precision and recovery of the method by using microwave assisted extraction were tested,and values of RSD′s (n=5) and recovery found were in the ranges of 2.1%-2.4% and 54.2%-100.1% respectively.