Size exclusion chromatography/mass spectrometry applied to the analysis ofpolysaccharides

A novel method for analysing polysaccharide materials is described which em ploys size-exclusion chromatography (SEC) followed by detection by on-line electrospray ionisation mass spectrometry (ESI-MS) and off-line matrix-assi sted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TO FMS). It is demonstrated through SEC/ESI ion trap mass spectrometry that th e formation of multiply charged oligomer ions, which bind up to five sodium cations, allows the rapid analysis of polysaccharide ions with molecular w eights in excess of 9 kDa. MALDI spectra generated from fractionation of th e effluent collected from the same SEC separation are shown to be in good a greement with the ESI spectra with respect to molecular weight distribution s and types of ions generated. ESI and MALDI mass spectra of samples obtain ed from sequential graded ethanol precipitation and SEC fractionation of ac id and enzymatically digested arabinoxylan polysaccharides show important s tructural differences between polysaccharide fragments. In addition, a comp arison is made between the mass spectra of native and permethylated SEC-sep arated fragments of acid and enzymatically treated arabinogalactan. Linkage information of the permethylated arabinogalactan oligomers can be rapidly established through the use of on-line SEC/ESI-MSn experiments. Copyright ( C) 2001 John Wiley & Sons, Ltd.