Poly(itaconic acid)-grafted silica stationary phase prepared in deep eutectic solvents and its unique performance in hydrophilic interaction chromatography.

In this study, a new stationary phase based on poly(itaconic acid)-grafted silica (Sil-PIA) were synthesized in deep eutectic solvents (DESs) and characterized in detail. Itaconic acid was homopolymerized on silica via surface radical chain-transfer reaction using DESs as a new kind of green solvents. Sil-PIA were obtained and characterized by Fourier transform infrared spectroscopy, elemental analysis and scanning electron microscopy. The retention changes of nucleosides and nucleobases on the columns was studied under different chromatographic conditions including salt concentration, acetonitrile content, mobile phase pH, and column temperature. Compared with previous reported poly(acrylic acid)-grafted silica (Sil-PAA) stationary phase, Sil-PIA possesses shorter retention time but similar or higher selectivity for the separation of most polar compounds such as bases, nucleosides, amino acids, and saccharides in hydrophilic interaction chromatography. Most importantly, Sil-PIA presents very good performance at the separation of eleven ginsenosides using isocratic elution in hydrophilic chromatography.