Precursor Carboxy-silica for Functionalization With Interactive Ligands. II. Carbodiimide Assisted Preparation of Silica Bonded Stationary Phases with D-glucamine for Hydrophilic Interaction Liquid Chromatography

A precursor carboxy-silica support was introduced for grafting a retentive polar ligand, namely D-glucamine, for use in hydrophilic interaction liquid chromatography. This support was prepared by sequentially reacting 5 µm silica particles with vinyltrimethoxysilane and then thioglycolic acid. The carboxy-silica thus obtained was subsequently functionalized with D-glucamine by on-column reactions via a carbodiimide conjugation reaction. These reactions series, which are applied for the first time in HPLC column fabrication, yielded the D-glucamide-silica column. This polar column was evaluated for its hydrophilic interaction chromatography retention properties with derivatized mono- and oligosaccharides, phenolic and benzoic acid derivatives, nucleobases, nucleosides and nucleotides. The D-glucamide-silica column exhibited a good selectivity towards most of the hydrophilic solutes investigated. The derivatized sugars with the fluorescing 6-aminoquinoline tag were detected at a very low level of 7 × 10–8 mol/L, a fact that allowed the visualization of maltooligosaccharides up to a dp of 17.