General mechanism of the chromatography of macromolecules: Experimental test of the universal nature of adsorption effects

Chromatographic data have been obtained for polyethylene glycols, polypropylene glycols, and polyvinylpyrrolidones, based on the use of four different adsorbents at different temperatures and pH values of aqueous buffer eluents. The experimental results are interpreted from the standpoint of a general theory of chromatography of polymers, accounting for adsorption interactions. Comparison between experiment and theory has made it possible to determine the adsorption interaction parameter, c, and the mean thickness of long adsorbing macromolecules, H, at different pH values and temperatures for various polymer-adsorbent systems. According to the theory, the parameter U = (K - K-GPC)/(1 - K-GPC) is a universal function of the product of gyration radius R and adsorption parameter c. In fact, the entire set of experimental data fit the same U versus cR relationship. Predicted from theory, the universal character of manifestation of adsorption effects in the chromatography of polymers has been tested experimentally for most diverse systems, viz. polymers of various chemical nature and molecular weights, adsorbents having various structures and pore sizes, aqueous and organic eluents, as well as for different methods to realize and change adsorption interactions. (C) 1997 Elsevier Science Ltd.