Updated project metadata. In this study, we identified and quantified the relative glycan distribution on UTI-Fc using nanoHILIC-MS for comprehensive mapping O-glycopeptides in UTI-Fc fusion protein. We quantified O-glycosylated peptides in the Fab domain and describe in detail for the first-time unexpected O-glycosylation at the linker and Fc region in UTI-Fc. These results highlight the improved performance of nanoHILIC-MS for characterization of biotherapeutic protein glycosylation in comparison to RP nanoLC-MS methods.