Acetonitrile, HPLC grade, was from J and K Chemical Co. Standard Mogroside V was from Tauto Biotech Co., Shanghai. Chitosan was obtained from Dandong Chemical Factory. The Amberlite XAD16 resin was purchased from Rohm and Haas, and the D213 resin was obtained from Dandong Chemical Factory. All the other reagent were of analytical grade.