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Chiral recognition of imperanene enantiomers by various cyclodextrins: A capillary electrophoresis and NMR spectroscopy study
Author(s) -
Sohajda Tamás,
Szakács Zoltán,
Szente Lajos,
Noszál Béla,
Béni Szabolcs
Publication year - 2012
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.201100560
Subject(s) - capillary electrophoresis , enantiomer , nuclear magnetic resonance spectroscopy , chemistry , chromatography , electrophoresis , cyclodextrin , spectroscopy , organic chemistry , physics , quantum mechanics
The enantiomers of imperanene, a novel polyphenolic compound of I mperata 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 CD s 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 p H ) R S = 4.47 was achieved using a 12.5 m M sulfobutyl‐ether‐ γ ‐ CD and 10 m M 6‐monodeoxy‐6‐mono‐(3‐hydroxy)‐propylamino‐ β ‐cyclodextrin dual system. The average stoichiometry of the complex was determined with J ob'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.