Tandem MS of the saccharide [6,3,3][0,0,0], [M + 2Na]2+ m/z 1220.4479 was performed on an LTQ-Oribtrap XL mass spectrometer in positive ion mode. CID fragmentations of the precursor ion m/z 1220.4479 (A) and MS3 of the product ion at m/z 833.3003 (B) are displayed on the chemical structures. Monosaccharide residues abbreviations QM (Qui4NFm), GN (GalNAcAN), and QC (QuiNAc) are shown inside the six-member rings for clarity. All fragments contain sodium.