Characterization of acid–base and complexation properties of cellulose degradation products using capillary electrophoresis Original Research Article

The acid–base and complexation properties of cellulose degradation products were evaluated using capillary electrophoresis. Alteration of the electrolyte pH was carried out to modify the degree of dissociation of the solutes ((hydroxy)carboxylic acids). The subsequent change of the effective mobility was plotted against the electrolyte pH and fitted with non-linear regression. Acidity constants were deduced; they are in good agreement with the literature data. A similar procedure was undertaken to study the complexation behaviour of the degradation products towards two cations, nickel(II) and lanthanum(III). The required experimental conditions are discussed, mainly from the electrolyte constituents standpoint. Addition of a cation in the electrolyte selectively modified the effective mobility of the solutes and mathematical linearization yielded estimates of the stability constants. Calculation of the stability constants of degradation products with only little complexation ability was often impossible, because of experimental data dispersion. For all the other products, the calculated values are consistent with those taken from the literature. They are typical of carboxylic acid complexation towards these metals.