Wang RQ, Ong TT, Tang W, Ng SC. Cationic cyclodextrins chemically-bonded chiral stationary phases for high-performance liquid chromatography.
Anal Chim Acta 2012;
718:121-9. [PMID:
22305907 DOI:
10.1016/j.aca.2011.12.063]
[Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Revised: 12/13/2011] [Accepted: 12/24/2011] [Indexed: 10/14/2022]
Abstract
Two covalently bonded cationic β-CD chiral stationary phases (CSPs) prepared by graft polymerization of 6(A)-(3-vinylimidazolium)-6-deoxyperphenylcarbamate-β-cyclodextrin chloride or 6(A)-(N,N-allylmethylammonium)-6-deoxyperphenylcarbamoyl-β-cyclodextrin chloride onto silica gel were successfully applied in high-performance liquid chromatography (HPLC). Their enantioseparation capability was examined with 12 racemic pharmaceuticals and 6 carboxylic acids. The results indicated that imidazolium-containing β-CD CSP afforded more favorable enantioseparations than that containing ammonium moiety under normal-phase HPLC. The cationic moiety on β-CD CSPs could form strong hydrogen bonding with analytes in normal-phase liquid chromatography (NPLC) to enhance the analytes' retention and enantioseparations. In reversed-phase liquid chromatography (RPLC), the analytes exhibited their maximum retention when the pH of mobile phase was close to their pK(a) value. Inclusion complexation with CD cavity and columbic/ionic interactions with cationic substituent on the CD rim would afford accentuated retention and enantioseparations of the analytes.
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