CAPILLARY ELECTROPHORESIS OF CARBOXYLATED CARBOHYDRATES - IV - ADJUSTING THE SEPARATION SELECTIVITY OF DERIVATIZED CARBOXYLATED CARBOHYDRATES BY CONTROLLING THE ELECTROLYTE IONIC-STRENGTH AT SUBAMBIENT TEMPERATURE AND IN THE ABSENCE OF ELECTROOSMOTIC FLOW

The effect of the ionic strength of the running electrolyte on selecti vity and resolution of 7-aminonaphthalene-1,3-disulfonic acid (ANDSA) derivatives of carboxylated monosaccharides and sialooligosaccharides derived from gangliosides was evaluated in capillary electrophoresis i n the absence of electroosmotic flow and at subambient temperature. Th e acidic saccharides used in this study were derivatized with ANDSA fl uorescing tag to facilitate their detection by laser-induced fluoresce nce. To maximize resolution among the derivatized saccharides, commerc ially available fused-silica capillaries with 'zero' electroosmotic fl ow having polyvinyl alcohol coating on their inner walls were used as the separation capillaries. The effective electrophoretic mobility (mu ) of the various ANDSA derivatized mono-and oligosaccharides decreased linearly with the inverse of the square root of the buffer concentrat ion (1/root C) used in the running electrolyte. The extent of screenin g of the charge on the solute by the electrolyte counterions varied am ong the various saccharides as was manifested by the slopes of the lin es of mu vs. 1/root C. Increasing the ionic strength of the running el ectrolyte allowed, via its charge screening effect, the modulation of selectivity thus adjusting the resolution of closely related saccharid es. (C) 1997 Elsevier Science B.V.