Analysis of carbohydrates by mass spectrometry

The analysis method described in this chapter demonstrates the structural characterization of carbohydrates based on their molecular mass, as well as the mass of their respective fragment ions using mass spectrometry (MS). The carbohydrate molecules are first converted into gaseous ions, under vacuum, after which their mass-to-charge ratio is measured. The mass-to-charge ratio provides information on their preliminary identification, which is further elucidated by fragmenting the ions under a process of collision-induced dissociation. The masses obtained in the first stage of MS together with those obtained in the subsequent stages (MSn) are combined into a mass list that is loaded into the program, Virtual Expert Mass Spectrometrist (VEMS) v3.0. The mass lists obtained are then used by VEMS to search a database of glycans to give the identity of the carbohydrate and the correct assignment of the fragment ions.