Rapid determination of trace uranium in high hardness groundwater by ultraviolet pulse-induced fluorescence method via the pre-treatment approach of carbonate separation

In this paper, a new method was studied in detail for the determination of trace uranium in high hardness groundwater by ultraviolet pulse-induced fluorescence method via the pre-treatment approach of carbonate separation. Tests revealed that it is a very effective method to separate the UO₂(CO₃)₂^2- from the Ca²⁺ and Mg²⁺ if adding 1.20 mL Na₂CO₃ (70 mg·mL^-1) to the 20.00 mL tested high hardness groundwater. Moreover, no obvious fluorescence quenching happened and the pH is still maintained at 7-9 during measuring the fluorescence intensity. The pre-separation procedure is easy and quickly. The detection limit of this method is above 0. 02 μg·L^-1, the recovery is in the range of 99%-101%, and the RSD is less than 5%. (authors)