CHEMOMETRIC ANALYSIS - URANIUM(VI) HYDROLYSIS BY UV-VIS SPECTROSCOPY

By application of factor analysis and statistics to 25 UV-Vis absorpti on spectra of hydrolyzed U(VI) solutions, single component-spectra of oligomeric U(VI) hydrolysis species (UO2)(2)(OH)(2)(2+) and (UO2)(3)O( OH)(3)(+) (=(UO2)(3)(OH)(5)(+)) are obtained. These two species are ab le to interpret all 25 spectra quantitatively. High molar absorptions of the characteristic low-energy electronic transition of U(VI) are fo und: 101+/-2 l mol(-1) cm(-1) for (UO2)(2)(OH)(2)(2+) at 421.8 nm and 474+/-7 l mol(-1) cm(-1) for (UO2)(3)O(OH)(3)(+) at 429.0 nm. Drastica lly higher integral oscillator strengths f for these oligomeric specie s compared to UO22+ (aq) are obtained: f(22)=2x10(-3) and f(35)=6x10(- 3), while f(10)=1.7x10(-4). Statistical analysis of target transformat ion analysis is made by Jackknife statistics and compared to Clifford' s calculational method. (C) 1998 Published by Elsevier Science S.A.