Amino-terminated ionic liquid modified graphene oxide coated silica composite stationary phase for hydrophilic interaction chromatography

Abstract

In this study, an amino-terminated ionic liquid modified graphene oxide coated silica composite stationary phase (IL@GO@SiO₂) has been synthesized and applied for the separation of B vitamins, amino acids and aromatic acids in hydrophilic interaction chromatography (HILIC) mode. The synthesized novel material was characterized by elemental analysis, field emission scanning electron microscopy and infrared spectroscopy. The chromatographic properties of the IL@GO@ SiO₂ phase were compared with those of the pure silica phase, amino-terminated ionic liquid modified silica phase, and graphene oxide modified silica phase. The results show that IL@GO@SiO₂ exhibits the best separation efficiency compared to the other three phases, which is ascribed to the existence of the multiple interactions, i.e., electrostatic interactions, π–π interactions and dipole–dipole interactions between the resulting stationary phase and the analytes. The differences between the four stationary phases illustrate that the combination of IL and GO plays an important role in improving the separation efficiency.