CE-MSn of complex pectin-derived oligomers
Coenen, G.J. ; Kabel, M.A. ; Schols, H.A. ; Voragen, A.G.J. - \ 2008
Electrophoresis 29 (2008)10. - ISSN 0173-0835 - p. 2101 - 2111.
anion-exchange chromatography - capillary zone electrophoresis - trap mass-spectrometry - hairy ramified regions - maldi-tof ms - rhamnogalacturonan-i - 8-aminonaphthalene-1,3,6-trisulfonic acid - galacturonic acid - apple pectin - oligosaccharides
As pectin molecules are too large and heterogeneous to analyze as a whole, the polymer is usually degraded to smaller oligomers, which are often analyzed by high-performance anion exchange chromatography (HPAEC). However, the high salt concentration necessary to elute pectin oligomers by HPAEC is incompatible with online mass detection. To overcome such a disadvantage, a CE-IT-MS system was set up to further elucidate the fine structure of charged oligosaccharides. An effective separation of differently substituted galacturonic acid containing oligomers was obtained by low-pH CE-LIF analysis. By adapting the buffer and capillary online MS detection was enabled. Moreover, with MS/MS it was possible to localize sugar residues' substitutions. With this combined CE-MS approach LIF electropherograms of xylogalacturonan and rhamnogalacturonan I digests could be annotated. The method was further exemplified by a complex oligomer mixture of acid hydrolyzed apple pectin, which was separated and characterized by CE-MSn. Oligomers present in low amounts could be localized by their corresponding m/z, as was demonstrated by selected mass range representation.