| Capillary electrocbromatography (CEC) is a recently developed micro-column separation technique which combines the high efficiency of capillary electrophoresis and high selectivity of high performance liquid chromatography. Accordingly, it has attracted more and more attention. The migration behavior of ionic compounds in CEC was theoretically studied by phenomenological approach. The acid and base dissociation equilibrium was considered first time for studying the migration behavior of weak base and acid. The influences of some parameters like pH value etc. on electrochromatographic retention factor were discussed. A model was developed for prediction of electrochromatographic retention factor of ionic compounds in pressurized flow CEC at different voltage or pressure, which was helpful for the optimization of the separation. Separation of ionic compounds by reversed-phase CEC (RP-CEC) meets some difficulties. Ion-exchange CEC (JE-CEC) was developed for separation of ionic compounds in this work. It was found small peptides and organic acids could be separated quickly with high efficiency. However, the ability of IE-CEC for separation of neutral compounds is poor, therefore, a new mode of CEC, so called CEC with dynamically modified stationary phase (DMS-CEC), was developed. The hydrophobicity of ion-exchange stationary phase was increased greatly after dynamically modified by surfactant, thereby, the retention of neutral compounds on the stationary phase was increased. Accordingly, simultaneous separation of ionic and neutral compounds can be realized in DMS-CEC. If the stationary phase was dynamically modified by some agent with chiral selectivity, DMS-CEC can also be used for chiral separation. Separation of strong polar compounds by RP-CEC is difficult, therefore, a new mode of normal phase CEC棗hydrophilic interaction CEC (I-il-eEC) was developed. It was found that strong polar compounds could be separated effectively in HI-CEC.
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