Rapid determination of uranium activity and concentration in water by alpha liquid scintillation with α/β discrimination

A rapid, robust and simple method has been developed to measure uranium in all kinds of water samples, even those with very high salinity (e.g. 130 g kg-1 dissolved solids). The method is based on simple chemical treatment, only involving addition of diethylenetriaminepentaacetic acid. Sample preparation is carried out within 2 h for 100 mL samples. One optional step has been inserted for a few samples to specifically remove Po because of interference with the 232U spike in the alpha energy spectrum. Chemical yield is about 100% for most water samples. A particular deconvolution process of alpha energy spectra is applied to perform accurate determination. The detection limit is equal to 0.2 μg kg-1, i.e. 0.003 Bq kg-1 for 240,000 s counting-time. Accuracy, precision, reliability and reproducibility have also been assessed. Reproducibility is within 5%. This method shows very good agreement with international and national intercomparison exercises for various water samples