Speciation studies of aluminium(III)-acetate complexes under physiological conditions

Abstract

The aluminium complexes of acetic acid (ACT) have been studied using potentiometric titrations under physiological conditions of temperature (37°C) and ionic strength (0.15moldm-3 NaCl) and at different ligand to metal ratios. The variations of pH were measured with the help of a glass electrode calibrated daily in hydrogen ion concentrations. Results obtained within the pH range of 2.6-4.2 were analysed to determine stability constants using the SUPERQUAD program. Different complex combinations were considered during the calculation procedure, and evidence was found for ML 2 mononuclear species beside binuclear hydroxo-complexes M 2L(OH)2 and M2L(OH)3 and metal ion hydroxides. Speciation calculations based on the corresponding constants were then used to simulate species distributions.