ELECTROMIGRATION BEHAVIOR OF POLYSACCHARIDES IN CAPILLARY ELECTROPHORESIS UNDER PULSED-FIELD CONDITIONS

Various polysaccharides can successfully migrate through entangled pol ymer solutions during high-voltage capillary electrophoresis. For neut ral polysaccharides, complexation with borate provides the electric ch arge needed for electromigration, while a fluorescent tag is needed to detect the solute bands with adequate sensitivity. At constant potent ials between 50 and 300 V/cm, the charged polysaccharides undergo mole cular stretching, resisting the desired separation according to their molecular mass. This problem can be overcome through the use of variab le fields, pulsed along the separation capillary at a 180-degrees angl e. Variables of the pulsing experiment appear to have a profound influ ence on molecular shape rearrangements of polysaccharides with respect to the separation medium, as demonstrated here with highly efficient separations of polydextrans (8,000-2,000,000 Da).