Investigation on molar mass, solubility and enzymatic fragmentation of xylans by multi-detected SEC chromatography

Four xylan samples front different origin were investigated, using a multi- detector, size exclusion, chromatographic system with two chromatographic c olumn sets and mobile phases differing in the DMSO:water ratio. Molar mass distribution could be analysed best using a mobile phase of DMSO:water (90: 10) with addition of 0.05 M LiBr, a system offering good solubilisation of the polymers and a proper chromatographic separation. SEC analysis in aqueo us systems provided information on solubility and aggregation of xylans. A comparison of UV- and RI-signals in different systems gave further informat ion on lignin impurities, which in some cases were involved in aggregation phenomena. Both analytical systems were applied to study the enzymatic frag mentation of xylans. Combining the information derived from the two systems can differentiate between the enzymatic degradation of the well-dissolved and the associated polymer fractions. (C) 2001 Elsevier Science Ltd. All ri ghts reserved.