Preparation of a dextran sulfate functionalized monolithic silica column for hydrophilic interaction/cation exchange chromatography

A new mixed-mode hydrophilic interaction/cation exchange monolithic silica stationary phase was prepared by chemical modification of a monolithic silica skeleton by dextran sulfate (DS) using 3-aminopropyl-triethoxysilane as a cross-linking agent. The characteristics of the DS column were evaluated by the separation of various biomolecules including amino acids, nucleosides and bases, nucleotides, and peptides. Good separations for these polar biomolecules were obtained within 11 min on the column using isocratic mode. The investigation for the separation mechanism indicated that strong hydrophilic and electrostatic interactions combined to play a role in the separation of these biomolecules on the DS column.