Zhang Xiaofeng, Xu Yi, Zhang Qing, Cao Kun, Mu Xiuni
Chemistry and Chemical Engineering College, Chongqing University, Chongqing, 400030, China; Chemistry and Chemical Engineering College, Chongqing University of Technology, Chongqing, 400054, China; International R & D center of Micro-nano Systems and New Materials Technology, 400030, China.
Chemistry and Chemical Engineering College, Chongqing University, Chongqing, 400030, China; International R & D center of Micro-nano Systems and New Materials Technology, 400030, China.
J Chromatogr B Analyt Technol Biomed Life Sci. 2016 Sep 15;1031:29-36. doi: 10.1016/j.jchromb.2016.06.052. Epub 2016 Jun 30.
A dual-task method for the simultaneous separation and purification of (-)-epigallocatechin gallate (EGCG) and caffeine (CAF) from crude extract of green tea was established by size exclusion effect onto hydroquinone modified porous adsorbents. The results showed that hydroquinone modified porous adsorbents P4 provided the best separation power due to it has more porous structure and phenolic hydroxyl group. The adsorption-desorption behaviors of EGCG and CAF onto P4 adsorbents were investigated. Adsorption kinetics of EGCG and CAF results showed that the adsorption followed the pseudo-second-order kinetic model. The results also indicated that the equilibrium adsorption data best fit the Langmuir model. Meanwhile, EGCG and CAF were separated successfully onto P4 adsorbents packed columns in a gradient eluent process, and P4 adsorbents exhibited the size exclusion effect for small molecules CAF. Based on the phenolic hydroxyl group and size exclusion effect of P4 adsorbents, the high purity EGCG and CAF were obtained with 40% (v/v) ethanol eluent successively. The process fulfilled the task of simultaneous separation and purification of EGCG and CAF, and proved to be a promising basis for preparations of difficult to obtain active components that have similar polarity and different sizes of molecules and derived from the same natural products.
通过对苯二酚改性多孔吸附剂的尺寸排阻效应，建立了一种从绿茶粗提物中同时分离纯化（-）-表没食子儿茶素没食子酸酯（EGCG）和咖啡因（CAF）的双任务方法。结果表明，对苯二酚改性多孔吸附剂P4具有最佳的分离能力，因为它具有更多的多孔结构和酚羟基。研究了EGCG和CAF在P4吸附剂上的吸附-解吸行为。EGCG和CAF的吸附动力学结果表明，吸附遵循准二级动力学模型。结果还表明，平衡吸附数据最符合朗缪尔模型。同时，在梯度洗脱过程中，EGCG和CAF在P4吸附剂填充柱上成功分离，P4吸附剂对小分子CAF表现出尺寸排阻效应。基于P4吸附剂的酚羟基和尺寸排阻效应，依次用40%（v/v）乙醇洗脱剂获得了高纯度的EGCG和CAF。该过程完成了EGCG和CAF的同时分离纯化任务，为制备难以获得的、具有相似极性和不同分子大小且来源于同一天然产物的活性成分提供了一个有前景的基础。
