Development and chromatographic exploration of stable-bonded cross-linked amino silica against classical amino phases

The present work reports on a novel stable-bonded amino silica stationary phase obtained by crosslinking of surface aminopropyl moieties using triglycidyl isocyanurate. The obtained cross-linked amido-amino network silica material exhibited superior hydrolytic stability compared to classical 3-aminopropyl phases and showed, inter alia, excellent separation of nine therapeutically effective sulfonamides in hydrophilic interaction/weak anion exchange chromatography elution mode. Additionally, the separation of carbohydrates was investigated under classical hydrophilic interaction chromatography conditions as well proving the suitability of the novel phase for such applications. For the evaluation of the hydrolytic stability the prepared material, as well as two commercially available benchmark columns and a set of in-house synthesized amino-modified materials, were exposed to harsh aqueous mobile phase conditions for in total of 50 h at elevated temperature. In this context, the materials were examined by elemental analysis, (¹³ C and ²⁹ Si cross-polarization/magic angle spinning) solid-state nuclear magnetic resonance, and a chromatographic test before and subsequent to the exposure to these stress conditions. Lastly, the new stationary phase was classified in comparison to a set of commercially available stationary phases by principal component analysis of resultant retention factors gained from chromatographic standard tests.