Utilization of dual retention mechanism on columns with bonded PEG and diol stationary phases for adjusting the separation selectivity of phenolic and flavone natural antioxidants.
The retention of phenolic acid and flavone antioxidants was investigated on three columns with bonded PEG, hydroxy (DIOL) and mixed oxyethylene-hydroxy (Luna HILIC) stationary phases in buffered aqueous ACN mobile phases. All columns show mixed retention mechanism: reversed phases in highly aqueous mobile phases and normal phases (HILIC, hydrophilic interaction LC) in mobile phases with high concentration of ACN, showing characteristic U-shape retention versus mobile phase composition plots. Equations enabling description and prediction of retention of sample compounds over the full mobile phase composition range were compared. Dual retention mechanism offers possibilities for using differences in selectivity between the two separation modes on a single column to improve the separation of natural antioxidants. The Luna HILIC column shows larger HILIC retention range, enhanced retention, improved selectivity and better peak symmetry in comparison to the PEG and DIOL columns.
Department of Analytical Chemistry, Faculty of Chemical Technology, University of Pardubice, Pardubice, Czech Republic. Pavel.Jandera@upce.cz
Pavel
P
Jandera
Tomás
T
Hájek