LAUSR

Abstract Fractional extraction was conducted to accurately separate puerarin from the crude Pueraria extract. Two green, efficient extraction systems of pure solvents were explored for the successive purification of puerarin by fractional extraction. The extraction systems of pure solvents do not involve chemical reactions, which is beneficial for product recovery and solvent reuse. A mathematical model of fractional extraction was established to investigate the effect of various parameters on extraction performance, including the organic/water phase ratio and the number of stages. The residual rate was proposed to assess the purity of puerarin. By simulation and optimization, the optimal parameters can be determined. Puerarin with high purity of 98.0% was continuously obtained by two-step fractional extraction in two cascades of 10 CCSs. Fractional extraction is an effective method for the accurate separation of active ingredients in Chinese herbal medicine on a commercial scale.