On-line direct determination of the second virial coefficient of a natural polysaccharide using size-exclusion chromatography and multi-angle laser light scattering

By combining a size-exclusion chromatographic (SEC) separation and an on-line multi-angle light scattering (MALLS) analysis, we have elaborated an original methodology permitting on-line direct determination of the second virial coefficient of molar mass fractions of polydisperse polysaccharides. By assimilating the SEC–MALLS data to a batch mode acquisition, we have obtained on-line the complete Zimm plot of the eluted fractions, leading to knowledge of their weight-average molar mass M w, radius of gyration r g and second virial coefficient A 2. Our methodology was successfully applied to a iota carrageenan sample in LiCl 100 m M, EDTA 1 g/l.