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Comparative NMR and MS studies on the mechanism of enantioseparation of propranolol with heptakis(2,3‐diacetyl‐6‐sulfo)‐β‐cyclodextrin in capillary electrophoresis with aqueous and non‐aqueous electrolytes
Author(s) -
Lomsadze Ketevan,
Salgado Antonio,
Calvo Enrique,
Antonio López Juan,
Chankvetadze Bezhan
Publication year - 2011
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.201000672
Subject(s) - chemistry , enantiomer , electrolyte , aqueous solution , cyclodextrin , capillary electrophoresis , nuclear overhauser effect , nuclear magnetic resonance spectroscopy , mass spectrometry , analyte , chromatography , analytical chemistry (journal) , nuclear chemistry , organic chemistry , electrode
In our recent studies, the reversal of the enantiomer migration order (EMO) was observed with heptakis (2,3‐dimethyl‐6‐sulfo)‐β‐CD (HDMS‐β‐CD) when aqueous electrolyte was changed with nonaqueous electrolyte in CE. One‐dimensional rotating frame nuclear Overhauser effect spectroscopy experiments prevailed that an inclusion complex was formed between the analyte and the chiral selector in the aqueous buffer, whereas an external complex resulted when a methanolic electrolyte was employed. In the case of the similarly substituted heptakis (2,3‐diacetyl‐6‐sulfo)‐β‐CD (HDAS‐β‐CD), the external complex was observed in the aqueous buffer but an inclusion complex was formed in methanolic electrolyte. In contrast to heptakis (2,3‐dimethyl‐6‐sulfo)‐β‐CD, no reversal of the enantiomer migration order was observed with HDAS‐β‐CD. In the present study, further mechanisms of enantioselective recognition and separation of propranolol enantiomers with HDAS‐β‐CD were investigated by using different techniques of nuclear magnetic resonance spectroscopy and high‐resolution mass spectrometry. To the best of our knowledge, enantioselective nuclear Overhauser effect was observed for the first time in this study.