DETERMINATION OF THE SUBSTITUENT PATTERN OF HETEROGENEOUSLY AND HOMOGENEOUSLY SYNTHESIZED CARBOXYMETHYL CELLULOSE BY USING HIGH-PERFORMANCELIQUID-CHROMATOGRAPHY

A rapid and convenient procedure was developed for the determination o f the substituent pattern of carboxymethyl cellulose (CMC) by means of high-performance liquid chromatography. The hydrolysates of CMC are s eparated on a polystyrene-based strong cation-exchange resin into gluc ose, 2,3,6-tri-O-carboxymethyl glucose and groups of 2-, 3- and 6-mono -O- and 2,3-, 2,6-, and 3,6-di-O-carboxymethyl glucoses. By this metho d the determination of the average degree of substitution as well as t he substituent pattern is possible. In this way we found that CMC samp les which were synthesized in LiCl/N,N-dimethylacetamide as a cellulos e solvent, contain a significantly higher amount of both tricarboxymet hylated and unsubstituted units than those obtained in a slurry of cel lulose in isopropanol/water at comparable DS values. The substituent p attern of heterogeneously synthesized CMC is mainly determined by stat istics.