After the analysis of caffeine standard solutions,we turned our attention to the analysis of caffeine in raw material and decaffeinates,and the chromatograms are presented in figure 4.A series of experiments were conducted in which the flow rate and mobile phase concentration were adjusted in an attempt to improve peak symmetry.We hoped this would keep the chromatography simple while minimizing overall time to analysis.The optimization process parameters of ultrasonic-enhanced supercritical removing caffeine proved to be very effective at removing caffeine.Compared to the peak area of caffeine in raw material,the peak area of caffeine in decaffeinates was successfully minished.The value of the caffeine peak decreased nearly 83.28% after caffeine removal.