title: Simultaneous separation and purification of (-)-epigallocatechin gallate and caffeine from tea extract by size exclusion effect on modified porous adsorption material.
abstract: 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.
authors.affiliation: 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.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Chemistry and Chemical Engineering College, Chongqing University, Chongqing, 400030, China; International R & D center of Micro-nano Systems and New Materials Technology, 400030, China. Electronic address: 1506515889@qq.com.
authors.forename: Yi
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Chemistry and Chemical Engineering College, Chongqing University, Chongqing, 400030, China; International R & D center of Micro-nano Systems and New Materials Technology, 400030, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Chemistry and Chemical Engineering College, Chongqing University, Chongqing, 400030, China; International R & D center of Micro-nano Systems and New Materials Technology, 400030, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Cao
authors.affiliation: Chemistry and Chemical Engineering College, Chongqing University, Chongqing, 400030, China; International R & D center of Micro-nano Systems and New Materials Technology, 400030, China.
authors.forename: Xiuni
authors.initials: X
authors.lastname: Mu
mesh_terms: D000327:Adsorption; D002110:Caffeine / Q000302:isolation & purification*; D002392:Catechin / Q000031:analogs & derivatives* / Q000302:isolation & purification; D002850:Chromatography, Gel / Q000379:methods*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D007700:Kinetics; D016062:Porosity; D013056:Spectrophotometry, Ultraviolet; D013662:Tea / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D013662:Tea; D002110:Caffeine; D002392:Catechin; C045651:epigallocatechin gallate
keywords: (−)-Epigallocatechin gallate; Caffeine; Hydroquinone modified adsorbents; Porous structure; Size exclusion effect