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Qin Q.,South China Normal University | Zhang S.,National University of Singapore | Zhang W.-G.,South China Normal University | Zhang Z.-B.,South China Normal University | And 6 more authors.
Journal of Separation Science | Year: 2010

In this study, the CD derivative, mono (6A-azido-6 A-deoxy)-per(p-chlorophenylcarbamonylated) β-CD was chemically immobilized onto the surface of an aminofunctionalized silica gel with different pore (100, 300, and 500Å) and particle (3, 5, and 10 mm) sizes to obtain novel chiral stationary phases. The impact of pore and particle size on the amount of immobilized Ph-b-CD, column performance, and enantioselectivity was investigated by evaluating the separation of a variety of racemates in both the normal- and the reversed-phase modes. Experimental results revealed that the retention factor and resolution of racemates generally decreased with increasing pore size; the column prepared with the smallest (3 μm) silica gel particle size gave the best column performance and enantioselectivity in both the normal- and the reversed-phase modes. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA. Source


Wang Q.,South China Normal University | Xiong Y.,South China Normal University | Lu B.,Guangzhou Research and Creativity Biotechnology Ltd | Fan J.,South China Normal University | And 3 more authors.
Journal of Separation Science | Year: 2013

N-(2,4-dinitrophenyl)-proline and N-(2,4-dinitrophenyl)-serine were enantiomerically resolved on the BSA chiral stationary phase by HPLC in reversed-phase mode. Effects of chromatographic conditions on enantioseparation and elution order have been investigated in detail. For these two samples, reversal of enantiomer elution order was observed by changing buffer pH, the content of acetonitrile, or alcohol modifiers in mobile phase, which is firstly reported in the BSA chiral stationary phase studies. More interestingly, combined effect between buffer pH and the content of acetonitrile was also observed. In addition, coelution range of enantiomers varied along with the content of acetonitrile in mobile phase. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Fang Z.,South China Normal University | Fang Z.,East China Jiaotong University | Guo Z.,South China Normal University | Qin Q.,South China Normal University | And 4 more authors.
Journal of Chromatographic Science | Year: 2013

A direct semi-preparative high performance liquid chromatography (HPLC) enantioseparation of ofloxacin was performed on chemically immobilized cyclodextrin derivative-mono (6A-azido-6A-deoxy)-per(p-chlorophenyl carbamoylated) β-CD chiral stationary phase. Conditions for semi-preparative separations were established using a 250 × 4.6 mm i.d. column and subsequently extended to a 250 × 10.0 mm i.d. column that enabled separations on a milligram scale. Optimization of the chromatographic conditions (mobile phase and column load) with respect to better efficiency, resolution and peak retention resulted in a system capable of separating up to 304 mg of (-)-(S)-ooxacin and 56 mg of (+)-(R)-ooxacin of the racemate over 6 h. The purities of the separated enantiomers were determined by HPLC. Moreover, both separated enantiomers were characterized by mass spectrometry; then, the absolute configuration of the products was clearly confirmed by polarimetry. © The Author [2012]. Published by Oxford University Press. All rights reserved. Source


Fan Q.,South China Normal University | Zhang K.,South China Normal University | Tian L.-W.,Guangzhou Research and Creativity Biotechnology Ltd | Fan J.,South China Normal University | And 3 more authors.
Journal of Chromatographic Science | Year: 2014

A new cyclodextrin-derived chiral stationary phase (denoted as CDA-CSP) was synthesized by immobilizing mono(6A-azido-6A-deoxy)- per(p-chlorophenyl carbamoylated) β-cyclodextrin derivative to alkynyl modified silica via click chemistry. This newly prepared CSP shows good enantioseparation performance for six chiral compounds (1-6), such as 4-phenyl-oxazolidine-2-thione, two kinds of aryl alcohols, substituted flavonoids and benzoin, in which baseline separation of Analytes 1-4 was achieved under the experimental conditions. The effects of column temperature, mobile phase pH and content of methanol on the enantioseparation characteristics of CDA-CSP were investigated in detail. Retention factor and resolution for Compound 3 gradually reduced with an increase of column temperature, and a good linear relationship was shown between napierian logarithm of selectivity factor and reciprocal of column temperature. In the pH range from 3.56 to 5.50, a change in pH hardly affected the resolution of Analyte 2. In addition, increasing methanol in the mobile phase resulted in rapid eluting of the analytes from the column in reversed-phase mode. The retention factors for Analytes 1 and 3 significantly decreased and their resolution showed different trends. © The Author [2013]. Published by Oxford University Press. All rights reserved. Source


Liu W.-N.,South China Normal University | Fan J.,South China Normal University | Lin C.,South China Normal University | Zheng S.-R.,South China Normal University | And 2 more authors.
Journal of Chromatographic Science | Year: 2015

A new cyclosporine-bonded stationary phase has been synthesized through the Staudinger reaction between azido cyclosporine A (CsA) and aminopropyl silica gel and applied in separations of six disubstituted aromatic analytes by high-performance liquid chromatography. For dimethyl phthalate, nitroaniline and chloronitrobenzene, their positional isomers were well-separated on this CsA stationary phase, in which the separation factor for m-/o-dimethyl phthalates was the biggest. For nitrotoluene, dichlorobenzene and benzenediol, the m-/o-isomers were co-eluted. Then, effects of chromatographic conditions (such as types and content of alcoholic modifiers) on separation of nitroaniline positional isomers have been investigated. Retention behaviors of nitroaniline isomers on the column exhibited the strengthening trend along with increasing carbon number of alcohols, from ethanol to 1-propanol, and to 1-butanol. A similar phenomenon was observed by lowering the content of alcohol. © The Author 2014. Published by Oxford University Press. Source

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