A QUALITATIVE STUDY TO THE INFLUENCE OF MOLAR-MASS ON RETENTION IN GRADIENT POLYMER ELUTION CHROMATOGRAPHY (GPEC)

Gradient Polymer Elution Chromatography (GPEC) appears to be a powerfu l method for the determination of chemical composition distributions ( CCD) of high molar mass copolymers. In order to perform these experime nts, molar mass dependence of the retention time must be minimized. It is shown that variation in solvent and non-solvent strength is a powe rful method for adjusting the molar mass dependence. There appears to be a relation between molar mass dependence of retention behavior in G PEC on one hand and solubility under critical solvent conditions on th e other hand. This phenomenon can be explained qualitatively from the important precipitation/redissolution mechanism in GPEC.