Sensitivity improvement in the analysis of oligosaccharides by on-line high-performance anion-exchange chromatography/ion spray mass spectrometry
✍ Scribed by R. A. M. van der Hoeven; A. J. P. Hofte; U. R. Tjaden; J. van der Greef; Nelson Torto; L. Gorton; G. Marko-Varga; C. Bruggink
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 172 KB
- Volume
- 12
- Category
- Article
- ISSN
- 0951-4198
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✦ Synopsis
The on-line coupling of high-performance anion-exchange chromatography (HPAEC) with ion spray mass spectrometry, for the analysis of neutral and acidic oligosaccharides, is described. On-line desalting is performed by a cation-exchange membrane system which replaces sodium for hydronium ions from the effluent stream by means of either electrolysis of water or a combination of electrolysis and pneumatically supplied sulphuric acid. In contrast to formerly described systems no booster pump between the cationexchange system and the ion spray interface is needed, due to the almost complete absence of back-pressure. The on-line removal of sodium ions prior to the interface by means of electrolysis, and use of ion spray as an ionization technique, enables the routine use of gradients of sodium acetate up to a total sodium concentration of 0.6 M. After optimization of the HPAEC/MS system molecular mass determination could be obtained at concentrations down to 3 mg/mL (20 ng of each compound) for a-1, 4-glucose oligomers up to a degree of polymerization of 7 (DP7). For maltodextrines the applicable mass range could be extended to over 3000 Da by the detection of at least DP20, as the doubly charged disodiated molecule. A series of galacturonic acid oligomers could be detected up to DP4 at a concentration of 10 mg/mL (67 ng per compound), using a sodium acetate gradient increasing to a total sodium concentration of 0.6 M.