Glycopeptide MRM/SRM. (A) General schematic representation of multiple reaction monitoring (MRM). Peptides and glycopeptides from a protease (normally trypsin)-cleaved glycoprotein are subjected to triple quadrupole mass spectrometry (MS). Only selected parent ion ions were selected for fragmentation, and the resulting fragment ion intensities were used for (glyco)peptide quantification. (B) Representative chromatogram of simultaneous MRMs of 25 pyridyl amineated sialoglycopeptides found on 16 glycoproteins in mouse serum. Adapted and modified from Kurogochi et al. .