title: Calixarene ionic liquid modified silica gel: A novel stationary phase for mixed-mode chromatography.
abstract: A novel calixarene ionic liquid functionalized silica material was synthesized by the preparation of a new calixarene monomer and its grafting on mercaptopropyl modified silica gel. The material was characterized by infrared spectra, elemental analysis, and thermogravimetric analysis. To explore the retention mechanism of the stationary phase, linear solvation energy relationships (LSER) equation as an effective mathematical model was used. In addition to this, the distinct separation mechanisms were outlined by selected examples of chromatographic separations in the different modes. In reversed-phase liquid chromatography, this new stationary phase presented specific chromatographic performance when evaluated using alkylbenzenes, PAHs and phenols as solutes. Due to the existing polar functional groups, this stationary phase can also be used in hydrophilic interaction chromatography, six nucleosides and four ginsenosides were separated successfully in hydrophilic mode. Furthermore, anions can be separated on the column in anion exchange mode. Thus, this new material was can be applied as a new kind of mixed-mode stationary phase in liquid chromatography, which allows an exceptionally flexible adjustment of retention and selectivity by tuning the experimental conditions.
authors.affiliation: Henan University of Traditional Chinese Medicine, Zhengzhou 450008, PR China; College of Chemistry and Molecular Engineering, Key Laboratory of Chemical Biology and Organic Chemistry of Henan, Zhengzhou University, Zhengzhou 450052, PR China.
authors.forename: Kai
authors.initials: K
authors.lastname: Hu
authors.affiliation: College of Chemistry and Molecular Engineering, Key Laboratory of Chemical Biology and Organic Chemistry of Henan, Zhengzhou University, Zhengzhou 450052, PR China.
authors.forename: Wenfen
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Henan University of Traditional Chinese Medicine, Zhengzhou 450008, PR China.
authors.forename: Huaixia
authors.initials: H
authors.lastname: Yang
authors.affiliation: Henan University of Traditional Chinese Medicine, Zhengzhou 450008, PR China.
authors.forename: Yongxia
authors.initials: Y
authors.lastname: Cui
authors.affiliation: Henan University of Traditional Chinese Medicine, Zhengzhou 450008, PR China.
authors.forename: Jingya
authors.initials: J
authors.lastname: Zhang
authors.affiliation: School of Chemistry and Chemical Engineering, Henan University of Technology, Zhengzhou 450001, PR China. Electronic address: wjzhao@126.com.
authors.forename: Wenjie
authors.initials: W
authors.lastname: Zhao
authors.affiliation: College of Chemistry and Molecular Engineering, Key Laboratory of Chemical Biology and Organic Chemistry of Henan, Zhengzhou University, Zhengzhou 450052, PR China.
authors.forename: Ajuan
authors.initials: A
authors.lastname: Yu
authors.affiliation: College of Chemistry and Molecular Engineering, Key Laboratory of Chemical Biology and Organic Chemistry of Henan, Zhengzhou University, Zhengzhou 450052, PR China. Electronic address: zsszz@126.com.
authors.forename: Shusheng
authors.initials: S
authors.lastname: Zhang
keywords: Calixarene ionic liquid; Mixed-mode chromatography; Separation mechanism; Stationary phase