Simultaneous determination of theanine,catechins and alkaloids in tea by HPLC-PDA
One method which could simultaneously determine the main components in tea,such as C,EC,EGC,ECG,EGCG,GCG,caffeine,theobromine,theophylline,theanine and gallic acid,was built by using HPLC-PDA.The method performed with a C18 chromatogram column and gradient elution at column temperature 25℃ and PDA detector at 190 nm and 280 nm.Mobile phase A was 0.05% trifluoroacetic acid and mobile phase B was acetonitrile.The flow rate was 1mL·min-1 and injection volume was 5 μL.The results showed that the calibration curves between peak areas and contents of components in tea were linear within the suitable concentration range.R2 was between 0.9989 and 0.9997,the mean recovery rates were from 96.31% to 103.13%.It is proved that this method is convenient and precise,which could be used for determination of catechins,theanine and alkaloids in tea and tea extracts.