Ultrasound Changes Solid-liquid Leaching Equilibrium of Glycyrrhizic Acid from Glycyrrhiza Uralensis in Water

This work reported that ultrasound changed the solid-liquid leaching equilibrium of glycyrrhizic acid (GA) from glycyrrhiza uralensis in water. Several critical variables were considered, including temperature, ultrasonic power and frequency. The equilibrium concentration of GA increased by increasing the temperature, while the optimal ultrasonic frequency was affected by the temperature and the ultrasonic power affected the concentration lightly when the power was more than 100W. To investigate the cause that ultrasound changed the solid-liquid leaching equilibrium, a scanning electron microscope was used to observe the solid structure before ultrasound treatment and after that. It was found that ultrasound was able to change the structure of glycyrrhiza uralensis. So a new equilibrium was built and the equilibrium concentration of GA was influenced because the solid structure was transformed by ultrasound.