Size Exclusion Chromatography of Nonionic and Anionic Copolymers of Vinylpyrrolidone

Abstract

Size exclusion chromatography (SEC) of poly(vinylpyrrolidoneco-vinylacetate), PVPVA, and poly(vinylpyrrolidone-co-dimethylamincethylmethacrylate-co-vinylcaprolactan),PVPDMMAEMAVC, is evaluated in terms of resolution between polymer and solvent peaks using aqueous and nonaqueous mobile phases. A 1:1 (v/v) water/methanol, 0.1M LiNO₂ mobile phase is used with four Waters Ultrahydrogel columns with pore sizes of 120Å, 500Å, 1000Å, and 2000Å. DMF, 0.1M LiNO₃ mobile phase is used with three different two column sets. Two of the column sets are comprised of a mixed bed packing of poly(styrene-co-divinyl benzene), obtained from Shodex (KD80M), followed by either an Ultrahydrogel 120Å or a PLge1 100Å. The third two column set is a PLge1 10⁴Å followed by a PLgel 500Å. Any of the second columns in these sets improve separation between the trailing end of the polymer peak and the leading end of the solvent peak but the column set using an Ultrahydrogel 120Å yields a separation of these peaks whose valley is closer to the baseline. The aqueous mobile phase with the four column set yields a separation between the trailing end of the polymer peak and the leading end of the solvent peak whose valley is closest to the baseline. Recovery of PVPVA and PVPDMAEMAVC from the columns evaluated is 100%. Vinylpyrrolidone compositions of PVPVA ranging from 30 to 70 mole % were studied using both mobile phases. SEC of