Figure 8. Tandem MS of the 18O labeled saccharide [6,3,3][0,0,0] reveals the reducing-end residue.
Tandem MS of the 18O labeled saccharide [6,3,3][0,0,0], [M + 2Na]2+ m/z 1221.4487 was performed on an LTQ-Oribtrap XL mass spectrometer in positive ion mode. CID fragmentations of the precursor ion are indicated on the chemical structure. Monosaccharide residues abbreviations QM (Qui4NFm), GN (GalNAcAN), and QC (QuiNAc) are shown inside the six-member rings for clarity. All fragments contain sodium.