A comprehensive study on the size exclusion chromatography of kappa-carrageenan for the identification of after-peaks



Aqueous size exclusion chromatography (SEC) of polysaccharides in general and carrageenans in particular is complicated by a number of factors. The chromatograms of carrageenans which are sulfated anionic natural polymers contain a number of after-peaks depending on the occlusion, adsorption, or association of various ionic species either naturally present or evolved during their processing. A systematic SEC analysis of after-peaks appearing in the chromatograms was made to identify the species responsible for their formation. The five after-peaks constantly appearing in the aqueous (0.1M NaNO3) SEC of kappa-carrageenan are attributed to sulfate, chloride, and nitrate anions whereas the first three and the fourth are due to divalent cations, mostly, and the fifth appears to result from the unknown impurities. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013