Direct determination of uranium in the organic phase D2EHPA-TOPO using XRF spectroscopy

Three calibration curves have been carried out to determine uranium concentration in the organic phase (D2EHPA-TOPO) using XRF technique with Cd109 as a primary exciting source. Copper was used as an internal standard, so the linear relation between relative intensity of uranium against its concentration has been obtained. The range of uranium concentrations studies are (0-100 μg.mL-1), (100-1000 μg.mL-1) and (1000-6500 μg.mL-1), which covered all uranium against its concentration concerning first and second cycles of uranium extraction from phosphoric acid. detection limit was found to be 1.1 μg/ml. The effect of different range of (0.2-0.6 M) D2EHPA and (0.025-0.15 M) TOPO and iron (0-500 μg.mL-1) on the accuracy and the precision of uranium determination have been studied and no effect was found. Unknown organic samples have been analyzed using XRF technique and compared with γ-ray, UV and volumetric techniques, obtained results were comparable. (Author)