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Enhanced electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry of long-chain polysaccharides.

Domenii publicaţii > Chimie + Tipuri publicaţii > Articol în revistã ştiinţificã

Autori: Perdivara I, Sisu E, Sisu I, Dinca N, Tomer KB, Przybylski M, Zamfir AD.

Editorial: John Wiley & Sons, Rapid Commun Mass Spectrom. , 22, p.773-782 , 2008.

Rezumat:

A novel strategy was developed to extend the application of electrospray ionization (ESI) Fourier
transform ion cyclotron resonance (FTICR) mass spectrometry (MS) to the analysis of long-chain
polysaccharides. High molecular weight polydisperse maltodextrins (poly-a(1-4) glucose) and
dextrans (poly-a(1-6) glucose) were chosen as model compounds in the present study. Increased
ionization efficiency of these mixtures in the positive ion mode was achieved upon modification of
their reducing end with nitrogen-containing groups. The derivatization method is based on the
formation of a new C–N bond between 1,6-hexamethylenediamine (HMD) and the reducing end of
the polysaccharide, which exists in solution as an equilibrium between the hemiacetal and the
open-ring aldehyde form. To achieve the chemical modification of the reducing end, two synthetic
pathways were developed: (i) coupling of HMD by reductive amination and (ii) oxidation of the
hemiacetal to lactone, followed by ring opening by HMD to yield the maltodextrin lactonamide of
1,6-hexanediamine (HMMD). Amino-functionalized polysaccharides were analyzed by electrospray
ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FTICR-MS) in the
positive ion mode by direct flow injection. The hexamethylenediamine (HMD) and maltodextrin
lactonamide of 1,6-hexanediamine (HMMD) moieties provide increased proton affinities which
dramatically improve the detection of the long-chain polysaccharides by FTICR-MS. The present
approach allowed for identification of single components in mixtures with prominent heterogeneity
in the degree of polymerization (DP), without the need for chromatographic separation prior to MS.
The high mass accuracy was essential for the unambiguous characterization of the species observed
in the analyzed mixtures. Furthermore, molecular components containing up to 42 glucose residues
were detected, representing the largest polysaccharide chains analyzed so far by ESI FTICR-MS.

Cuvinte cheie: spectrometrie de masa/FTICR/maltodextrine/dextrani // mass spectrometry/FTICR/maltodextrins/dextrans