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Determination of dissociation constants of flavonoids by capillary electrophoresis
Author(s) -
HerreroMartínez José M.,
Sanmartin Meritxell,
Rosés Martí,
Bosch Elisabeth,
Ràfols Clara
Publication year - 2005
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.200410258
Subject(s) - flavonols , deprotonation , morin , chemistry , capillary electrophoresis , dissociation constant , catechin , quercetin , fisetin , dissociation (chemistry) , ring (chemistry) , chromatography , analytical chemistry (journal) , computational chemistry , polyphenol , organic chemistry , biochemistry , ion , medicine , receptor , pathology , antioxidant
Ionization constants of some flavanols (catechin and epicatechin) and flavonols (kaempherol, fisetin, morin, and quercetin) are determined by capillary zone electrophoresis (CZE). This technique allows the determination of p K a values until about 12. The p K a values obtained are compared with those calculated by the SPARC computational program. This program predicts the microscopic and macroscopic p K a values and the order of deprotonation of the different −OH groups. While for catechin and epicatechin the first ionizable OH group occurs in ring 1 and the second ionizable group in ring 2, in flavonols the first deprotonation occurs in ring 2 and the second in ring 1.