Separation of Liquiritin by simulated moving bed chromatography

Liquiritin was extracted from the natural product Licorice, and then purified using a three-zone simulated moving bed set up in our laboratory, with a C(18)-bonded silica as the stationary phase and an aqueous solution of ethanol as the mobile phase. The isotherm parameters of Liquiritin and of the only closely eluting impurity were obtained using the inverse method, fitting the experimental elution profiles to calculated elution profiles, assuming a binary Langmuir isotherm model as an approximation. The operating parameters of the simulated moving bed were selected according to the Equilibrium Theory. This allowed the preparation of 85% pure Liquiritin. Finally, 99% pure Liquiritin was obtained through a last step of recrystallization.