Time-resolved laser-induced fluorescence is a unique method for direct uranium speciation at low level in the framework of environmental studies. By varying pH and uranium concentration in the absence of carbonate ions and at fixed ionic strength, it was possible, together with free uranyl UO2 2+, to identify spectrally and temporally all the uranium-hydroxo complexes, namely, UO2 OH+, UO2 (OH)2 , UO2 (OH)3-, (UO2)2(OH)2 2+, (UO2)3(OH)5+, and (UO2)3(OH)7-.
Christophe Moulin, Ivan Laszak, Valerie Moulin, and Christian Tondre, "Time-Resolved Laser-Induced Fluorescence as a Unique Tool for Low-Level Uranium Speciation," Appl. Spectrosc. 52, 528-535 (1998)