Preparation and evaluation of two silica-based hydrophilic-hydrophobic and acid-base balanced stationary phases via in-situ surface polymerization

Two new hydrophilic-hydrophobic and acid-base balanced liquid chromatographic stationary phases were obtained by using two long-chain monomers including undecylenic acid (UA) and oleic acid (OA) combined with short-chain 4-vinyl pyridine (Py) in-situ polymerized on silica microspheres surfaces, respectively. These two stationary phases can be used for reversed-phase liquid chromatography (RPLC) and hydrophilic interaction liquid chromatography (HILIC) modes. Hydrophilic, hydrophobic, acidic and basic analytes can be separated on two new stationary phases in RPLC or HILIC mode. Compared with commercial hydrophobic C18 columns and other HILIC columns, two new stationary phases have excellent selectivity and separation performance in the separation of 9 polycyclic aromatic hydrocarbons, 10 aromatic acids, 10 anilines and 5 oxazolidinones, respectively. This novel polymer-functionalized silica design strategy has opened up new ideas for the future of mixed-mode stationary phases with multiple functions and specificity.