THE INFLUENCE OF BUFFER COMPOSITION ON SEPARATION EFFICIENCY AND RESOLUTION IN CAPILLARY ELECTROPHORESIS OF 8-AMINONAPHTHALENE-1,3,6-TRISULFONIC ACID LABELED MONOSACCHARIDES AND COMPLEX CARBOHYDRATES

The effect of buffer conditions - varying in salt type, pH, and concen tration - on the separation of 8-aminonaphthalene-1,3,6-trisulfonic ac id (ANTS)-labeled monosaccharides and complex-type carbohydrates was i nvestigated. Different buffer systems for high and low electroosmotic non conditions were chosen: a phosphate and a citrate background elect rolyte, each at pH 2.5, a phosphate buffer, pH 9.0, and a berate buffe r at pH 9.5. All buffer systems displayed differences In resolution an d selectivity. Phosphate and berate buffer demonstrated the greatest s electivity changes for ANTS-labeled carbohydrates. While separation in the phosphate system relies mainly on differences in the charge-to-ma ss-ratio, additional selectivity can be achieved with berate complexat ion of glycoconjugates. The use of berate buffers improve ed monosacch aride separations whereas complex carbohydrates showed a loss in resol ution. The citrate background electrolyte at low pH caused no signific ant changes in the separation performance. The pH 9.0 phosphate buffer showed a reversed migration order of the ANTS conjugates with a decre ased resolution, compared to the pH 2.5 phosphate buffer, due to the s trong electroosmotic flow generated under high pH conditions. An ovalb umin-derived oligosaccharide library demonstrates the significance of buffer selectivity for complex carbohydrate separations. The separatio n in the acidic phosphate and the alkaline berate buffer generates a d ifferent pattern and only the combination of both buffer systems allow s an appropriate assessment of sample complexity.