Preparation and chromatographic evaluation of a polymer-based stationary phase for weak anion-exchange/hydrophilic interaction

a weak cationic exchange/hydrophilic interaction mixed-mode stationary phase (Sil-PolyCOOH) for high performance liquid chromatography was prepared by bonding polyethylene maleic anhydride to the surface of amino silica gel via a nucleophilic substitution reaction, followed by hydrolysis of the residual maleic anhydride. The new stationary phase material was characterized by solid-state C-13 nuclear magnetic resonance analysis and zeta-potential measurements. The chromatographic performance and retention mechanism of this stationary phase were evaluated using nucleosides and nucleic bases as probes. The effects of mobile phase composition, ion strength, and pH on the retention factor were investigated. The results show that the retention mechanism of the stationary phase involves both hydrophilic distribution interaction and multiple forces between the host and guests. The stationary phase also showed good separation performance for saccharides, diquat, and paraquat. These results show that the stationary phase has a good application prospect in the separation of polar compounds.