Phase Separation and Extraction with n-Hexane for the Preparation of High Purity Chlorogenic Acid

Macroporous resin 306 adsorption followed by phase separation and extraction was used to purify the crude chlorogenic acid extract from Eucommia ulmoides leaves.Ethyl acetate was selected for the phase separation of chlorogenic acid.The individual effects of length of extraction,pH and extraction times on the yield of chlorogenic acid were investigated in the single factor experiments.Box-Behnken experimental design was employed to provide a basis for the development of a mathematical model predicting the yield of chlorogenic acid as a function of length of extraction,pH and extraction times and subsequently,the interactive effects of the independent variables on their function were analyzed using response surface methodology (RSM).The optimal values of the independent variables were found to be: extraction time 3.40 min,pH 2.97,extraction times 4.Under these optimal conditions,the maximum yield of chlorogenic acid reached up to 95.1%.Non-polar nhexane was found to be the best choice for the transfer of chlorogenic acid from ethyl acetate phase to water phase among the tested 4 solvents and its optimal amount was determined to be 40% of the volume of the ethyl acetate phase containing chlorogenic acid.As a result,93% of chlorogenic acid was transferred to the water phase.The purity of final chlorogenic acid product reached up to 99.5% (HPLC).