Hydrogen-bonding interaction-assisted capillary electrophoresis

Capillary electrophoresis using polyethers as hydrogen-accepting agents was developed. The addition of PEG as a matrix agent in CZE causes a selective decrease in the electrophoretic mobility of some substituted benzoates having hydrogen-donating substituents. The addition of non-ionic surfactants with a polyether structure to an SDS system for MEKC results in a selective increase in the relative capacity factors of some nonionic and cationic-substituted benzenes with hydrogen-donating substituents. These effects can be interpreted in terms of a hydrogen-bonding interaction between the ether oxygen atoms of the polyether agents and the substituents of analytes. Separation was well controlled by adjusting the PEG concentration and mixing ratio of the surfactants. The thermodynamic aspects of these separation systems are discussed in detail.