Study on Speciation of Uranyl Acetate Complex in Leaching Solution of Uranium Slag by Electrospray Ionization-Tandem Mass Spectrometry

Analysis method of uranium speciation is one of the key techniques to ensure the safe utilization of nuclear energy resources and the disposal of radioactive waste. In this work, electrospray ionization mass spectrometry (ESI-MS) was used to analyze uranium-containing compounds which [UO2]+ group was considered as qualitative standard. The group of [UO2]+ was split from uranyl-containing compounds under collision-induced dissociation mode with high energy of 120 eV. The speciation of uranyl complex in acetic acid eluent of uranium slag were determined for the first time, while uranyl speciation was difficult to analyze in the past due to low concentration of uranium in eluent and complicated matrix. Using the developed qualitative method, [UO2Ac]+, [UO2AcH2O]+, [UO2AcHAc]+, [UO2AcHAcH2O]+ and [UO2Ac(HAc)2]+ were found in acetic acid leachate, among which [UO2AcHAc]+ had the highest abundance. ESI-MS method had the advantages of practicality and strong anti-interference ability, which provided a new analytical method for the study of organic uranyl speciation.