Glutathione-modified ordered mesoporous silicas for enrichment of N-linked glycopeptides by hydrophilic interaction chromatography.

Hydrophilic interaction chromatography (HILIC), as one of the important methods for glycopeptides enrichment, has attracted the attention of more and more researchers due to the high efficiency in glycopeptides enrichment. Ordered mesoporous silica materials have been used in many fields, such as catalysis, separation and drug delivery, owing to their adjustable pore size, excellent mechanical properties and ease of preparation. In our case, a series of ordered mesoporous silicas with different pore sizes (3.7-16.7 nm) were prepared via sol-gel reaction employing F127 as the template and TEOS as the silica source. After modified with glutathione by photo-initiated thiol-ene reaction, these materials exhibited hydrophilicity and could be used as adsorbents of HILIC for capturing N-linked glycopeptides from IgG and serum protein tryptic digests. Up to 26 N-glycopeptides were identified from IgG digest, and 565 N-glycopeptides and 330 N-glycosylation sites, mapped to 159 glycoproteins, were identified from 2 μL human serum digest, indicating the great ability for enriching N-glycopeptides from complex biological samples.