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-carrageen an, 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 imp roved by using a sieving medium. The migration order can be entirely r eversed when the charge-to-friction ratio of the solute is decreased b y the end-label, The experimental electrophoretic mobilities obtained in this work are in excellent agreement with the recently reported the oretical 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, bu t no strong dependencies were found, Resolution between small oligomer s could be significantly improved by following this separation princip le.