Ionic Strength Dependence of Formation Constants: Complexation of Dioxouranium (VI) with Aspartic Acid

The dependence on ionic strength of protonation of L-aspartic acid and its complexation withdioxouranium(VI) is reported in sodium perchlorate solution as a background salt. The measurementshave been performed at 25 ± 0.1 °C and various ionic strengths in the range 0.1 to 1.0 mol dm-3, using acombination of potentiometric and spectrophotometric techniques. The overall analysis of the present andthe previous data dealing with the determination of stability constants at different ionic strengths allowedus to obtain a general equation, by which a formation constant determined at a fixed ionic strength can becalculated, with a good approximation, at another ionic strength, if 0.1 ≤ ionic strength ≤ 1.0 mol dm-3sodium perchlorate.