The structure of alginic acid. Part VI. Minor features and structural variations

Abstract

Nine alginate samples, isolated from different seaweed sources and varying in their relative contents of mannuronic acid and guluronic acid units, were examined by methylation, reduction, and hydrolysis. Three independent methods of g.l.c. were used to analyse the resulting mixtures of neutral sugars, and all samples were thereby shown to be linear and to contain no 1,3- or 1,2-linkages.

Similar methods have shown that the intact units in periodate-oxidised sodium alginate are 1,4- or 1,5-linked. A physical rather than a chemical explanation is favoured for the periodate resistance of alginates.