Division of Chemical and Biomolecular Engineering, College of Engineering, Nanyang Technological University, Singapore, Singapore.
Anal Chim Acta. 2012 Mar 9;718:121-9. doi: 10.1016/j.aca.2011.12.063. Epub 2012 Jan 8.
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.
两种通过接枝聚合将 6(A)-(3-乙烯基咪唑基)-6-去氧苯甲酰基-β-环糊精氯或 6(A)-(N,N-烯丙基甲基铵基)-6-去氧苯甲酰基-β-环糊精氯键合到硅胶上制备的共价键合的阳离子β-CD 手性固定相 (CSP) 已成功应用于高效液相色谱 (HPLC)。使用 12 种外消旋药物和 6 种羧酸检验了它们的对映体分离能力。结果表明，在正相 HPLC 中，含咪唑基的β-CD CSP 比含铵基的 CSP 提供了更有利的对映体分离。β-CD CSP 上的阳离子部分可以在正相液相色谱 (NPLC) 中与分析物形成强氢键，从而增强分析物的保留和对映体分离。在反相液相色谱 (RPLC) 中，当流动相的 pH 接近分析物的 pK(a) 值时，分析物表现出最大的保留。与 CD 腔的包络络合作用和 CD 边缘上的离子/离子相互作用会增强分析物的保留和对映体分离。
