Glycol Diglycidyl Ether and γ-Aminobutyric Acid Functionalized Silica as a Mixed Mode Stationary Phase for Capillary Liquid Chromatography

In this study, a mixed mode stationary phase for capillary liquid chromatography (cLC) was prepared by chemical modification of glycol diglycidyl ether (EGDE) and γ-aminobutyric acid (GABA) bonded to the silica, named as Sil–EGDE–GABA. The Sil–EGDE–GABA was characterized by Fourier transform infrared spectroscopy and elemental analysis. The retention of nucleotide bases at different acetonitrile levels in the mobile phase indicated that the stationary phase possessed both hydrophilic chromatography (HILIC) and reversed-phase chromatography (RPLC) characteristics. Positional isomers, aniline compounds and a mixture of polar–nonpolar analytes were separated in RPLC mode. The stationary phase exhibited different separation mechanisms in the separation of positional isomers, compared with a commercial ODS column. Sulfonamides and biogenic amines were successfully separated in HILIC mode. These results demonstrated the application possibilities of the prepared Sil–EGDE–GABA as packing materials in cLC.