Characterization of Chitosans via Coupled Size-Exclusion Chromatography andMultiple-Angle Laser Light-Scattering Technique. (Reannouncement with New Availability Information)

摘要

Chitosan ((1-->4)-2-amino-2-deoxy- -D-glucan), a cationic biopolymer, wasobtained by deacetylation of chitin samples from various sources. Nine chitosan samples differing in their degree of acetylation and molecular weight were used in this study. They were characterized by size-exclusion chromatography (SEC) coupled to a multiple-angle laser-scattering (MALLS) photometer. The results show that accurate, reliable, and reproducible molecular weight and radius of gyration data are obtained by using SEC-MALLS. These sample were also characterized by a conventional secondary calibration technique. The molecular weights obtained by secondary calibration were found to be 2-3 times higher than those obtained using SEC-MALLS. The dissimilarity between the chitosan samples and polymer standards employed for calibration were presumed to be responsible for overestimation of the molecular weights. Therefore, we conclude that the unavailability of chitosan polymer standards underscores the need for an absolute molecular-weight determination technique, such as SEC-MALLS.