Structure Elucidation of Carbohydrates by MALDI

Example The PSD-MALDI-TOF spectrum of the [M+Na] ion, m/z 1418.9, of high-mannose A-linked glycan (Man)6(GlcNAc)2 from chicken ovalbumin recorded from DHB shows distinct cleavages of the branched carbohydrate skeleton (Fig. 10.16). [134] 

Note Carbohydrates possess a high affinity towards alkali metal ions, and thus in MALDI spectra [M-tNa] and/or [M+K] are normally observed instead of or in addition to [Mh-H] ions of very low abundance. Radical ions are not observed. It basically depends on the relative amount of alkali ion impurities or dopant which quasimolecular ion will be dominant. 

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