Application of covalent coatings based on imidazolium cations for separation and online preconcentration of basic and neutral analytes in capillary electrophoresis

The method of capillary electrophoresis (CE) is actively developed and more and more attracts scientists attention every year. However, the sorption of analytes on surface of fused-silica capillary walls is one of the significant disadvantages of this approach. The formation of coatings on the inner capillary surface is typical way to prevent sorption and to increase separation efficiency and selectivity of determined analytes. Coatings that covalently bonded to capillary walls is more suitable because they are stable and provides high reproducibility of analysis. The present work is focused on the development of the method of electrophoretic determination of biological active analytes using a covalent coating based on imidazolium cations. The effect of substituent in imidazolium ring on main electrophoretic parameters was examined. It was shown that alkylimidazolium coatings contribute to significant reducing of biogenic amines limits of detection, while beta-cyclodextrinimidazolium covalent coating allows to separate both of hydrophobic and hydrophilic analytes in one run.