Journal of Chromatography & Separation Techniques
Open Access

Abstract

Separation of Resveratrol and Emodin by Supercritical Fluid-Simulated Moving Bed Chromatography

Ming-Tsai Liang, Ru-Chien Liang, Yu Shu-qi and Yan Ri-an

To separate resveratrol and emodin, supercritical carbon dioxide with ethanol was employed as the desorbent for a three-section simulated moving bed with an open-loop design called SF-SMB. Experimental validation of the separation was accomplished in this work. Silica was used as the stationary phase, and a crude extract of Polygonum cuspidatum containing mainly the resveratrol and the emodin, was purchased from a bio-technology company and used as the feedstock for the SF-SMB. Using single column chromatography, the operating conditions for a series of experiments conducted with 18 wt% ethanol were examined. The results were then compared to those predicted by the Triangle theory to determine the separable operating conditions and the dead volume of the SF-SMB unit. The robust operation of the SF-SMB against the concentration fluctuation of ethanol was also examined by conducting experiments with varied ethanol concentrations in different sections. It was found that the system is able to retain robust operation with about a 1.0 wt% ethanol fluctuation. Lowering the ethanol concentration to 15 wt% for each section was expected to relocate the separable operating conditions. A series of experiments with 12 wt% ethanol showed no pure raffinate. This is explained by the fact that the high flow rate of desorbent in the first section needed to obtain pure extract and raffinate would result in a high pressure drop, and lower the efficiency of the SF-SMB. From this study, the SF-SMB is demonstrated as being a useful technology for the separation of natural products, while providing a potentially greener alternative in the development of botanical drugs.