CHARACTERIZATION OF ACID-BASE AND COMPLEXATION PROPERTIES OF CELLULOSE DEGRADATION PRODUCTS USING CAPILLARY-ELECTROPHORESIS

The acid-base and complexation properties of cellulose degradation pro ducts were evaluated using capillary electrophoresis. Alteration of th e electrolyte pH was carried out to modify the degree of dissociation of the solutes ((hydroxy)carboxylic acids). The subsequent change of t he effective mobility was plotted against the electrolyte pH and fitte d with non-linear regression. Acidity constants were deduced; they are in good agreement with the Literature data. A similar procedure was u ndertaken to study the complexation behaviour of the degradation produ cts towards two cations, nickel(II) and lanthanum(III). The required e xperimental conditions are discussed, mainly from the electrolyte cons tituents standpoint. Addition of a cation in the electrolyte selective ly modified the effective mobility of the solutes and mathematical lin earization yielded estimates of the stability constants. Calculation o f the stability constants of degradation products with only little com plexation ability was often impossible, because of experimental data d ispersion. For all the other products, the calculated values are consi stent with those taken from the literature. They are typical of carbox ylic acid complexation towards these metals. (C) 1998 Elsevier Science B.V. All rights reserved.