Comparison of procainamide and 2-aminobenzamide labeling for profiling and identification of glycans by liquid chromatography with fluorescence detection coupled to electrospray ionization–mass spectrometry

One of the most widely used methods for glycan analysis is fluorescent labeling of released glycans followed by hydrophilic interaction chromatography-(ultra-)high-performance liquid chromatography [HILIC-(U)HPLC]. Here, we compare the data obtained by (U)HPLC-fluorescence (FLR) coupled to electrospray ionization-mass spectrometry (ESI-MS) for procainamide and 2-aminobenzamide (2-AB)-labeled N-glycans released from human immunoglobulin G (IgG). Fluorescence profiles from procainamide show comparable chromatographic separation to those obtained for 2-AB but gave higher fluorescence intensity as well as significantly improved ESI efficiency (up to 30 times that of 2-AB). Thus, labeling with procainamide increases the ability to identify minor glycan species that may have significant biological activity.