Gallium(III) Ion Hydrolysis under Physiological Conditions

The hydrolysis of gallium(III) has been studied using potentiometric techniques under physiological conditions of temperature 37 °C and ionic strength 0.15 mol·dm -3 NaCl and at different metal ion concentrations. Changes in pH were monitored with a glass electrode calibrated daily in hydrogen ions concentrations. The titration data within the pH range of 2.5-9.99 were analyzed to determine stability constants of hydroxide species using the SUPERQUAD program. Several different species were considered during the calculation procedure and the following hydroxides have been characterized: Ga(OH) 3, Ga(OH) 4 -Ga 3 (OH) 11 2- , Ga 4 (OH) 11 + and Ga 6 (OH) 15 3+ . Speciation calculations based on the determined constants were then used to simulate the species distribution.