Mass spectra of tryptic N-glycopeptide signals, at charge state 2. (A) main species G0F, G1F and G2F eluting at retention time 11.13–11.46 min, (B) high-mannose species M5, M6, M7 and M8 (for visualization signals are enlarged, y values multiplied by 5), eluting at retention time 10.50–10.97 min and (C) sialic acid containing species G1S1F and G2S1F (for visualization signals are enlarged, y values multiplied by 10) eluting at retention time 11.92–12.26 min in tryptic LC–MS analysis. Monosaccharide symbols follow the SNFG (symbol nomenclature for Glycans) system (PMID 26543186, Glycobiology 25:1323–1324, 2015) details at NCBI.