Practical Optimization Method for Dual-Flow Countercurrent Extraction: Purification of Glycyrrhizin

An optimization method for the dual-flow countercurrent extraction of a mixture, the components of which show a concentration dependency in its distribution ratio, has been developed. As an experimental demonstration, commercial glycyrrhizin (about 90% purity) was purified to 99.8% with high recovery using a two-phase system (1-butanol and 0.1 M NaCl) in the presence of 0.02 M tetrabutylammonium hydroxide, and under the optimum conditions of the present method. To acquire 90.0% recovery of glycyrrhizin in an organic extract, the flow rate of the organic solvent was calculated to be 0.943 ml/ min (aqueous solvent, 1.06 ml/ min). Extraction performed at the derived flow rates obtained 87.2% recovery of glycyrrhizin in the organic extract, showing the propriety of the optimization method.