RETENTION MECHANISM IN ZWITTERIONIC HYDROPHILIC INTERACTION LIQUID CHROMATOGRAPHY (ZIC-HILIC) STUDIED FOR HIGHLY POLAR COMPOUNDS UNDER DIFFERENT ELUTION CONDITIONS

摘要

The retention behavior of six highly polar compounds on zwitterionic sulfobetaine stationary phase was studied, under different elution conditions. The influence of organic modifier type (acetonitrile, methanol), the organic solvent content, ammonium acetate concentration added to the mobile phase and column temperature on the retention of studied compounds were investigated. Influence of temperature on the retention of studied compounds was also investigated and van't Hoff plotts were used in estimating thermodynamic parameters of the chromatographic process. Two mathematical models usually used to differentiate between partition and adsorption processes were applied to the dependences of retention factor on mobile phase composition. These obtained results suggest that a mixed retention mechanism relying on both partition and adsorption processes may contribute to the chromatographic behavior of studied compounds on ZIC-HILIC stationary phase.