Oligosaccharides preparative liquid chromatography

The pure oligosaccharides were obtained by preparative liquid chromatography from partially hydrolyzed polymers. Mixture of maltodextrins is a commercial sample obtained by partial enzymic and acid hydrolysis of starch (Roquette, France) Mixture of isomaltodextrins is prepared by partial acid hydrolysis of dextran. Cyclodextrins are commercial samples from Aldrich. 

Three soft ionisation methods are in use for earbohydrates, fast atom bombardment (FAB), eleetrospray ionisation (ESI) and matrix-assisted laser desorption/ionisation (MALDI). FAB is the oldest and involves directing a high-energy beam of Cs" ions or Xe atoms at the sample dissolved in a nonvolatile solvent such as m-nitrobenzyl alcohol. The atoms sputter the sample and matrix [M + H] or [M + Na]" ions are commonly observed. With an upper limit of M of about 2000, FAB is not that soft, and is usually used for small oligosaccharides it has the further disadvantage that the sample is prepared and then directly introduced into the mass spectrometer, so that it cannot be combined with liquid chromatography. 

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