title: Evaluation and application of a mixed-mode chromatographic stationary phase in two-dimensional liquid chromatography for the separation of traditional Chinese medicine.
abstract: In this study, two mixed-mode chromatography stationary phases (C8SAX and C8SCX) were evaluated and used to establish a two-dimensional liquid chromatography system for the separation of traditional Chinese medicine. The chromatographic properties of the mixed-mode columns were systematically evaluated by comparing with other three columns of C8, strong anion exchanger, and strong cation exchanger. The result showed that C8SAX and C8SCX had a mixed-mode retention mechanism including electrostatic interaction and hydrophobic interaction. Especially, they were suitable for separating acidic and/or basic compounds and their separation selectivities could be easily adjusted by changing pH value. Then, several off-line 2D-LC systems based on the C8SAX in the first dimension and C8SAX, C8SCX, or C8 columns in the second dimension were developed to analyze a traditional Chinese medicine-Uncaria rhynchophylla. The two-dimensional liquid chromatography system of C8SAX (pH 3.0) × C8SAX (pH 6.0) exhibited the most effective peak distribution. Finally, fractions of U. rhynchophylla prepared from the first dimension were successfully separated on the C8SAX column with a gradient pH. Thus, the mixed-mode stationary phase could provide a platform to separate the traditional Chinese medicine in practical applications.
authors.affiliation: School of Pharmacy, Engineering Research Center of Pharmaceutical Process Chemistry, Ministry of Education, East China University of Science and Technology, Shanghai, China.
authors.forename: Zhishen
authors.initials: Z
authors.lastname: Wei
authors.affiliation: School of Pharmacy, Engineering Research Center of Pharmaceutical Process Chemistry, Ministry of Education, East China University of Science and Technology, Shanghai, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Fu
authors.affiliation: School of Pharmacy, Engineering Research Center of Pharmaceutical Process Chemistry, Ministry of Education, East China University of Science and Technology, Shanghai, China.
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Cai
authors.affiliation: School of Pharmacy, Engineering Research Center of Pharmaceutical Process Chemistry, Ministry of Education, East China University of Science and Technology, Shanghai, China.
authors.forename: Liyun
authors.initials: L
authors.lastname: Huan
authors.affiliation: School of Pharmacy, Engineering Research Center of Pharmaceutical Process Chemistry, Ministry of Education, East China University of Science and Technology, Shanghai, China.
authors.forename: Jianchao
authors.initials: J
authors.lastname: Zhao
authors.affiliation: School of Pharmacy, Engineering Research Center of Pharmaceutical Process Chemistry, Ministry of Education, East China University of Science and Technology, Shanghai, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Shi
authors.affiliation: School of Pharmacy, Engineering Research Center of Pharmaceutical Process Chemistry, Ministry of Education, East China University of Science and Technology, Shanghai, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Jin
authors.affiliation: School of Pharmacy, Engineering Research Center of Pharmaceutical Process Chemistry, Ministry of Education, East China University of Science and Technology, Shanghai, China.
authors.forename: Xinmiao
authors.initials: X
authors.lastname: Liang
mesh_terms: D002853:Chromatography, Liquid; D004365:Drugs, Chinese Herbal / Q000737:chemistry / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D008516:Medicine, Chinese Traditional; D032070:Uncaria / Q000737:chemistry*
chemical_list: D004365:Drugs, Chinese Herbal
keywords: Mixed-mode chromatography; Stationary phases; Traditional Chinese medicine; Two-dimensional liquid chromatography