Enzyme-aided characterisation of carboxymethylcellulose

Two conventionally prepared carboxymethylcelluloses (CMCs) with differing degrees of substitution (DS: 0.6 and 1.2) were fragmented by endoglucanase treatment until no further degradation was possible. This treatment brought about a decisive improvement in the water solubility of the polymers. The degraded samples were separated into 18 fractions by size exclusion chromatography (SEC). The quality of the preparative SEC was monitored by analytical SEC equipped with a multiple detector system. After acidic hydrolysis of each individual fraction, the carboxymethyl derivatives of the anhydroglucose units were determined by anion exchange chromatography and pulsed amperometric detection. The accessibility of endoglucanase action was clearly a function of the degree of substitution (DS). As the DS increased the efficiency of the enzyme became more limited. It could also be demonstrated that the polysaccharide chain of both CMC samples included some regions that were highly substituted and some other regions of low substitution. (C) 1999 Elsevier Science Ltd. All rights reserved.