Separation and purification of EGCg in catechins by HP-20 macroporous resin.

The rude catechin extracts of EGCg(Epi-gallate-catechin-gallate) with 31.52% as raw material,the HP-20 macroporous resin was screened from the six kinds of macroporous resin of D202,XDA-1,D201,D900,LSA-7,HP-20 by comparing their effects of static adsorption and de-sorption on EGCg. The HP-20 macroporous resin was then applied for gradient elution and in-gradient elution experiment,and the technological parameters were optimized. The result showed that 1.8 g injection solution,2 BV/h flowing speed,40% ethanol,2 BV elution volume were the best parameters for gradient elution,and the purity and yield rate of EGCg reached 55.92% and 95.22% separately. While the parameters of 1.8 g injection solution,2 BV/h flowing speed,30% ethanol,2 BV elution volume and 1─2 BV collection volume were the best parameters for in-gradient elution,and the purity and the yield rate of EGcg reached 68.32% and 72.08% in sequence,which showed good application value in industry.