Platform for analysis of anthranilic acid N-glycan derivatives utilizing multipolarity mode LC-MS with hydrophilic interaction chromatography separation and ion trap MS/MS

Background: The structure of glycans is complex compared with linear polymers such as proteins and nucleic acids. Structural assignment of these compounds is particularly challenging to the bioanalyst. Here we present a multipolarity mode LC-MS platform for analysis of anthranilic acid-derivatized N-glycans. Results: Multipolarity mode LC-MS ana-lysis of N-glycan anthranilic aid (2AA) derivatives, collected under conditions that stabilize sialyloligosaccharides, provided more complete structural coverage than either mode when used alone. Structural assignment was simplified by the use of 2AA, which localizes charge to the reducing end in both modes facilitating the production of reducing end fragment dominant spectra. Conclusion: Multimode analysis of high-mannose, hybrid and complex N-glycans, under conditions used in this method, is superior to either mode when used alone.