From preparation of Sample 1 Japanese green tea : No sugar formula , Sample 2 Fujicha green tea : Natural , Sample 3 Oishi Green tea : Sugsr free. The Filter the solution with injection filter (cellulose filter). Sample standard filtration 0.2 µm. Filter through cellulose filter put into a small glass bottle and the Parafilm. Sheet. Come off the head of the bottle before were analyzed with HPLC. because Stationary Phase: Symmetry C18 3.9x150 mm ; 5 µm reverse phase. Let the determination was set up the suitable conditions of caffeine. The chromatography conditions were record, i.e. type of column, mobile phase, detector, eluent flow rate, etc. The filtered caffeine standards were inject 20 L and tea samples into the injection port. Let area data was obtain peaked and the concentration was determined of caffeine in the samples. The chromatograms were printed out of the solutions.