Sulfonated acrylamide copolymers as pseudo-stationary phases in electrokinetic chromatography

Sulfonated copolymers were synthesized, characterized and used as separatio n media in electrokinetic chromatography. The polymers used were synthesize d from AMPS (2-acrylamido-2-methyl-1-propanesulfonic acid) and LMAm (lauryl methacrylamide) in different mole ratios (from 100:0 to 60:40). Electropho retic mobilities and methylene selectivities were calculated, which showed the expected correlation with the monomer ratios. The chemical selectivitie s for the separation of nine solutes by the copolymers were compared with t hat of sodium lauryl sulfate micelles, showing significant differences. No significant difference in chemical selectivities was observed for copolymer s with different monomer ratios. No significant change of hydrophobic micro domain of copolymers was found in background buffers with different ionic s trength values, based on the investigation of the retention factors, methyl ene selectivities and polymer effective mobilities. No change of hydrophobi c microdomain of the copolymer solutions was found at copolymer concentrati ons from 0.17 to 3% (w/v), however, plots of k' versus polymer concentratio n suggested a different copolymer phase at lower concentrations (from 0 to 0.1%, w/v) from that at higher concentrations (from 0.17 to 3%, w/v). The c opolymer with AMPS-LMAm (80:20) could be chosen as optimum copolymer as far as the methylene selectivity, peak symmetry and polymer mobility were conc erned. (C) 2001 Elsevier Science B.V. All rights reserved.