Enzyme-aided characterization of carboxymethylcellulose with conventional and novel distribution of functional groups

A method has been developed for the characterization of carboxymethylcellulose (CMC), which gives a certain insight into the distribution of substituents along the cellulose chain. The method is based on the endoglucanase-catalysed fragmentation of the polysaccharide, followed by preparative size-exclusion chromatography (SEC). The material of each SEC fraction is subsequently converted into monosaccharides by acid hydrolysis, followed by quantitative HPLC determination of the individual building units of CMC. Basic differences were found for CMC samples, prepared according to different synthesis concepts. CMC-material prepared according to the traditional slurry method excelled by a relatively homogeneous distribution of substituents. However CMC specimen from a newly developed synthesis concept behaved completely different. Endoglucanase-cleaved fragments could be isolated, which were either rather high or rather low in their degree of substitution. This finding proves the existence of a novel blockwise substitution pattern.