Size exclusion chromatography of dextrans in DMSO as eluent

The elution conditions for an appropriate size exclusion chromatographic (S EC) characterization of dextrans were checked on a divinylbenzene grafted g lucose column. Different eluents were tested. With neutral aqueous eluents, the dextrans were irreversibly adsorbed. In KOH, the separation was rather good but we could note some elution volume shifts when the KOH concentrati on was changed, and the solute was rapidly degraded by hydrolysis. The mixt ures of DMSO/H2O did not enable the dextrans to completely dissolve and lar ge aggregates were present in the solution. In pure DMSO, even at 70 degree s C, the polysaccharides were only partially eluted. The addition of a smal l quantity of salt to DMSO allowed total recovery of the samples. In DMSO salt, the elution volumes shifted when we changed the nature of the salt b ut these differences were independent of the salt concentration. The second ary interactions were not relevant enough so that we could consider that th e dextrans were primarily eluted by means of size exclusion.