Preparation of glutathione-functionalized zwitterionic silica material for efficient enrichment of sialylated N-glycopeptides

A glutathione (GSH)-functionalized silica material was prepared using divinyl sulfone activation chemistry (named SiO 2 -DVS-GSH). The successful synthesis of the SiO 2 -DVS-GSH material was confirmed by FT-IR, elemental analysis, and zeta potential analysis. The effects of water content, pH value, and salt concentration in the mobile phase on the model compound (uracil, uridine, cytosine, cytidine, guanosine, xanthosine, orotic acid) retention was studied, and a hydrophilic interaction liquid chromatography (HILIC) retention feature together with electrostatic interaction of the SiO 2 -DVS-GSH material was observed. The prepared stationary phase was further applied for the separation of oligosaccharide. In addition, the SiO 2 -DVS-GSH material displayed remarkable selectivity and specificity for the sialylated N-glycopeptides’ enrichment from bovine fetuin tryptic digests, even at a mass ratio of 1:1000 ( w / w ) to bovine serum albumin (BSA, non-glycosylated protein), showing superior performance compared to commercial ZIC-HILIC material. Moreover, the SiO 2 -DVS-GSH material behaved well in the N-glycopeptides’ enrichment from human serum, demonstrating its promising potential for glycoproteomics of complex biological samples. Graphical Abstract A glutathione (GSH)-functionalized silica material was prepared using divinyl sulfone activation chemistry, and it shows remarkable selectivity and specificity for the sialylated N-glycopeptides’ enrichment.