D. Ekeberg et al., Negative-ion electrospray ionisation-mass spectrometry (ESI-MS) as a tool for analysing structural heterogeneity in kappa-carrageenan oligosaccharides, CARBOHY RES, 334(1), 2001, pp. 49-59
Oligosaccharides, enzymically produced from kappa-carrageenan, have been in
vestigated by electrospray ionisation mass spectrometry (ESI-MS). The techn
ique was used without prior derivatisation of the oligosaccharide originall
y obtained by size-exclusion chromatography (SEC). The structure of the oli
gosaccharides was mainly 4-sulphated neocarrabiose (A-G4S) with an increasi
ng length ranging from di- to dodecasaccharides. However, in the larger oli
gosaccharides, structural motifs deviating from the perfect alternating A-G
4S structure were detected, i.e. (A2S-G4S). Although resulting in reduced s
ignal intensity, samples to which NaCl was added also gave rise to reliable
mass spectra. Desulphation was induced at elevated cone voltages and in ac
idic or alkaline salt solutions. (C) 2001 Elsevier Science Ltd. All rights
reserved.