END-LABEL, FREE-SOLUTION CAPILLARY ELECTROPHORESIS OF HIGHLY-CHARGED OLIGOSACCHARIDES

The effect of fluorescent tags on the separation of negatively charged oligosaccharides, derived from a partially hydrolyzed kappa-carrageenan, was studied, When the charge-to-friction ratio of oligosaccharides is increased by the end-label, the migration order is from smaller to larger oligomers, and the resolution of larger oligomers could be improved by using a sieving medium. The migration order can be entirely reversed when the charge-to-friction ratio of the solute is decreased by the end-label, The experimental electrophoretic mobilities obtained in this work are in excellent agreement with the recently reported theoretical model (Mayer, P.; Slater, G. W.; Drouin, G. Anal. Chem. 1994, 66, 1777-1780). The maximum number of separated oligomers (M(max)) as a function of applied voltage and injection time was also studied, but no strong dependencies were found, Resolution between small oligomers could be significantly improved by following this separation principle.