Characterization of Polyvinylchloride by Size Exclusion Chromatography. I. Concentration Dependence of Axial Dispersion Observed in Size Exclusion Chromatography Coupled With Light Scattering

A comparative study on the axial dispersion in size exclusion chromatography was carried out on sample solutions with narrow molar mass distribution of polyvinylchloride (Mw=12000–96300 g/mol; Mw/Mn=1.14–1.25) and polystyrene (Mw=9000–1130000 g/mol Mw/Mn=1.04–1.08) in tetrahydrofuran. Determination of the axial dispersion parameter [Otilde] was accomplished by two independent methods for simultaneous calibration of separation and axial dispersion. For polystyrene, a slight dependence of [Otilde] on the peak elution volume was found as postulated in literature. At low concentration, there is a good agreement between [Otilde] measured for polystyrene (PS) and polyvinylchloride (PVC). Raising the concentration by a factor of 3, an increase of [Otilde] by about 25 % was found for PVC. The method of universal calibration proved to be applicable independent of concentration, when [η] =1.6 × 10−4 M0.706 dl/g for PS and [η] =1.6. × 10−4 M0,77 dl/g for PVC is used.