Elsevier

Analytical Biochemistry

Volume 268, Issue 2, 15 March 1999, Pages 213-222
Analytical Biochemistry

Regular Article
A Novel High-Performance Anion-Exchange Chromatographic Method for the Analysis of Carrageenans and Agars Containing 3,6-Anhydrogalactose

https://doi.org/10.1006/abio.1998.3059Get rights and content

Abstract

A novel method has been developed to determine the sugar composition of 3,6-anhydrogalactose-containing polysaccharides, such as carrageenan and agar. The method is based on reductive hydrolysis with a methylmorpholine–borane complex in the presence of acid and subsequent high-performance anion-exchange chromatography analysis of the alditols without any derivatization. The method was validated by13C NMR analysis of six carrageenans and three agars and by a previously used method based on derivatization to alditol acetates and gas–liquid chromatography analysis. The new method was found to be superior to the gas–liquid chromatography method as the analysis time was less than half. Also it was found to be more accurate and reproducible and no derivatization was required. The analysis of the six different carrageenan samples revealed that homogeneous mu- and nu-carrageenan, theoretically without 3,6-anhydrogalactose residues, cannot be isolated from red seaweeds. Consequently, the question arose if mu- and nu-carrageenans at all are present in seaweeds and if the current hypotheses regarding biosynthesis of carrageenans in the seaweeds are correct. The data demonstrated that carrageenans are highly complex natural polysaccharides, which are more irregular than assumed hitherto. The new analytical technique will permit elucidation of the detailed structure of seaweed polysaccharides and determination of their structure–property relationships.

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  • Cited by (0)

    Flick, G. G.Martin, R. E.

    1

    To whom correspondence should be addressed at Hercules European Research Center, P.O. Box 252, 3770 AG Barneveld, The Netherlands. Fax: (+31) 342 407 507. E-mail:[email protected].

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