Speciation of uranium by electrospray ionization mass spectrometry: Comparison with time-resolved laser-induced fluorescence

Speciation of actinides, lanthanides, and fission products is a major chall enge in the framework of nuclear fuel cycle studies. Electrospray-mass spec trometry has been used for uranium speciation. Free uranyl (UO22+), the fir st hydroxo complex (UO2OH+), and the oligomeric species (UO2)(3)(OH)(5)(+) have been observed as a function of pH. Different aqueous solvents (sodium perchlorate, perchloric acid/ammonium acetate, and perchloric acid/ammonia) were tested in order to limit the presence of adducts. The influence of va rious parameters such as the cone voltage, temperature, and gas flow rate i s presented. Comparison with results obtained by time-resolved laser-induce d fluorescence on the same solutions shows a similar tendency despite a sli ght shift in pH relative to the OECD database.