Interaction of Uranium(VI) with Bioligands Present in Human Biological Fluids: The Case Study of Urea and Uric Acid

The complexation of uranium(VI) with bioligands that found in human biological fluids, viz, urea and uric acid in aqueous solutions has been investigated using time-resolved laser-induced fluorescence spectroscopy (TRLFS) at room temperature, I = 0.1 M (NaClO4) and pH (3 for uric acid; 4 for urea). In both complex systems a static quench effect with increasing ligand concentration and no peaks shift upon complexation were observed. With uranium(VI) both ligands formed a fairly weak 1:1 complex with av-erage stability constants of log β110 = 4.67 ± 0.29 for uric acid and log β110 = 3.79 ± 0.15 and 2.12 ± 0.18 for relatively low and relatively high urea concentrations, re-spectively. Application of the newly generated data on the U(VI) speciation modelling in biofluids, e.g., human urine was also discussed.