Quantitative isomer-specific N-glycan fingerprinting using isotope coded labeling and high performance liquid chromatography-electrospray ionization-mass spectrometry with graphitic carbon stationary phase.

•We conducted relative quantification of labeled N-glycan isomers by HPLC–ESI-MS using porous graphitized carbon as stationary phase.•Relative quantification was done via labeling with [12C6]- and [13C6]-aniline.•The method was validated concerning reproducibility, linearity and LOQ/LOD.•PGC-ESI-MS was applied successfully to quantitate isomeric N-glycans released from human monoclonal antibodies produced in different cell lines.