Characterization of cellulose derivatives and their migration behavior in capillary electrophoresis

Uncharged chemically modified cellulose derivatives were mobilized in electric fields through the adsorption of charged and hydrophobic surfactant molecules. The steep and sudden onset in electrophoretic mobility was characteristic of a cooperative binding process and a migration model based on thermodynamic equilibria is presented along with experimentally determined association constants and aggregation numbers. Due to an uneven modification along the polymer chains, separation of different groupings within a sample mixture could be obtained and differently substituted celluloses were selectively distinguished. To discriminate between different preparations derivatized with the same substituent groups, enzymatic or acid hydrolysis was applied utilizing various enzymes with different origin as well as acids like hydrochloric, trifluoroacetic and perchloric acid. The methodology presented here might serve as a general approach for the assessment of cellulose derivative structures and their relation to technical properties desired in the food, medical and pharmaceutical industries.