A novel graphene oxide/chitosan foam incorporated with metal-organic framework stationary phase for simultaneous enrichment of glycopeptide and phosphopeptide with high efficiency.

A novel hydrophilic porous biocomposite was fabricated by incorporating graphene oxide (GO) @chitosan (CS) foam substrate (GO@CS@ZIF-8 foam) with ZIF-8 crystals in situ via a facile stirring method for simultaneous enrichment of glycopeptides and phosphopeptides from complex biological samples. The experimental results demonstrated that GO@CS@ZIF-8 foam exhibited favorable specificity for simultaneous enrichment of N-glycopeptides and phosphopeptides under the same condition for HRP and β-casein tryptic digest mixtures. The novel material was further applied to enriching both glycopeptides and phosphopeptides simultaneously from 4 μL complex human serum, and 423 N-glycopeptides and 40 phosphopeptides corresponding to 133 glycoproteins and 29 phosphoproteins were identified, respectively.