Demasking role of various complexans in the determination of uranium in torbernite ore using ion-pair HPLC

Abstract Various masking agents such as ethylenediamine tetra‐acetic acid (EDTA), diethylenetriamine penta‐acetic acid (DTPA), ethyleneglycol‐2‐(amino‐ethyl) tetra‐acetic‐acid (EGTA), ascorbic acid, fluoride, tartrate, citrate, oxalate, thiourea, triethanolamine (TEA), and ethylenediamine (EDA) have been used in the sample processing to eliminate the iron interference in the determination of uranium U (VI) by ion‐pair high performance liquid chromatography (IP‐HPLC). Among the investigated masking agents, oxalate, thiourea, TEA, EDA interfere. However, EDTA and DTPA, are effective to mask iron without affecting U (VI) quantification, while citrate slightly reduces the response. The lowest detection limits for the reported method in standard solution is 2 ppm. The developed method has been applied to analyze U (VI) in simulated standards and IAEA SRM, such as Torbernite ore containing iron. The relative standard deviation (RSD) for uranium determination in Torbernite ore (n=5) is ∼2%.