APPLICATION OF CAPILLARY ELECTROPHORESIS TO THE ANALYSIS OF THE OLIGOMERIC DISTRIBUTION OF POLYDISPERSE POLYMERS

Capillary electrophoresis was investigated for characterizing the oligomeric distribution of some model ionic and non-ionic synthetic polymers. Ionic poly(alkyl oxide) oligomers in the molecular mass range from a few hundred to over 4000 were separated into as many as 60 individual oligomers and detected using an indirect UV approach. Neutral Triton X series oligomers from n = 1 to n = 46 were separated in under 20 min using a sodium dodecyl sulfate matrix with high levels of acetonitrile. Separations have also been obtained on neutral poly(ethylene glycol) polymers after derivatization with phthalic anhydride. In all cases the analyses were conducted in the open tube CE format without the aid of sieving media Separations of individual oligomers were achieved by incorporating additives into the electrophoretic buffer to modulate either the charge on the surface of the capillary or the charge properties of the oligomeric analytes.