Carbohydrate Analysis by MALDI-MS

Example The maltose chains in the confectionery gummy bears consist of up to about 30 maltose units [73]. The signals originating from [M-t-Na] ions are spaced 162 u apart, i.e., by CgHioOs monomer units (Fig. 11.22). The difference between biopolymer or synthetic polymer is of minor significance when it comes to MALDI. 

Example The PSD-MALDI-TOF spectrum of the [M+Na] ion, m/z 1418.9, of high-mannose fV-linked glycan (Man)6(GlcNAc)2 from chicken ovalbumin shows distinct cleavages of the branched carbohydrate skeleton (Fig. 11.23). [171] The spectmm was obtained using DHB matrix. 

Note Carbohydrates possess a high affinity towards alkali metal ions, and thus in MALDI spectra [M+Na] and/or [M+K] are normally observed instead of or in addition to [M+H] ions of very low abundance. Radical ions are not observed. It generally depends on the relative amount of alkali ion impurities or dopant which ionic species will dominate the spectrum. 

---