Chiral recognition of imperanene enantiomers by various cyclodextrins: A capillary electrophoresis and NMR spectroscopy study

Abstract

The enantiomers of imperanene, a novel polyphenolic compound of Imperata cylindrica (L.), were separated via cyclodextrin-modified capillary electrophoresis. The anionic form of the analyte at pH 9.0 was subject to complexation and enantioseparation CE studies with neutral and charged cyclodextrins. As chiral selectors 27 CDs were applied differing in cavity size, sidechain, degree of substitution (DS) and charge. Three hydroxypropylated and three sulfoalkylated CD preparations provided enantioseparation and the migration order was successfully interpreted in each case in terms of complex mobilities and stability constants. The best enantioresolution (R(S) = 1.26) was achieved using sulfobutyl-ether-γ-CD (DS ∼4), but it could be enhanced by extensive investigations on dual selector systems. After optimization (CD concentrations and pH) R(S) = 4.47 was achieved using a 12.5 mM sulfobutyl-ether-γ-CD and 10 mM 6-monodeoxy-6-mono-(3-hydroxy)-propylamino-β-cyclodextrin dual system. The average stoichiometry of the complex was determined with Job's method using NMR-titration and resulted in a 1:1 complex for both (2-hydroxy)propyl-β- and sulfobutyl-ether-γ-CD. Further NMR experiments suggest that the coniferyl moiety of imperanene is involved in the host-guest interaction.

Twenty years of development of dual and multi‐selector models in capillary electrophoresis: A review

“…In several cases the complexation parameters were even determined but not used for the optimization (the complexation parameters were used, e.g. to optimize the single selector systems only or to clarify the electromigration order of the analytes ). When lucky, the trial‐error approach may be quicker compared to the optimization by mathematical modeling.…”

Structure selective complexation of cyclodextrins with five polyphenols investigated by capillary electrokinetic chromatography

“…In analytical science, CDs may alter the spectroscopic and electrochemical properties of guest molecule through complexes formation, which can be utilized in a variety of chemical analytical techniques . CDs can also recognize positional isomers and enantiomers, and are widely used for enantioseparations in HPLC , GC , and CE . The use of CDs as chiral selectors in CE has been extensively reviewed by Juvancz et al , Scriba , Fanali , and Chankvetadze .…”

Evaluation and comparison of three different separation techniques for analysis of retroamide enantiomers and their biological evaluation against h-P2X7 receptor

“…To save time and with regard to very recent works [30][31][32], the cationic MM-␤-CD was firstly tested, added to the initial 15 mM of SBE-␤-CD. An equimolar dual system was constituted containing 15 mM of MM-␤-CD and 15 mM of SBE-␤-CD.…”