The Molar Mass Measurement of Poly(allylamine hydrochloride) by Size Exclusion Chromatography/Multi Angle Light Scattering Method

Abstract

In SEC (size exclusion chromatography) measurements of cationic polymers, such as poly(allylamine hydrochloride), it is important to suppress any ionic interaction or hydrophobic interaction between a sample and a column packing material. In this study, regarding a new SEC column for exclusive use in cationic polymer analysis, which had been developed for this purpose, the elution behavior of polyallylamine hydrochloride was evaluated using the SEC/MALS method. When the NaNO₃ concentration in the eluant was 0.05, 0.1 or 0.2 mol/L, elusion with an excellent size-exclusion mechanism was confirmed for each case. In addition, it was clarified that following an increase in the salt concentration in the eluant, the radius of gyration of poly(allylamine hydrochloride) decreased, resulting in an increase in the elution volume. This fact suggests that, due to an increase in the ion concentration existing in the elutant, each others' repulsion among the cationic functional groups in the polymer molecules was suppressed.