Determination of small amounts of uranium by redox potentiometric titration

The redox titration of U in H3PO4 solution with an automatic titrator for determination of small amounts of U (0.1–0.2 mg) was studied. The choice of the oxidant appreciably affects the accuracy of the U determination, which decreases in the order KMnO4 > K2Cr2O7 > NH4VO3 > Ce(SO4)2. Irrespective of the oxidant used, the metrological characteristics of the method (repeatability r, laboratory precision R, and accuracy Δ) are significantly improved when the amount of U in the sample is increased from 0.1 to 0.2 mg, and high accuracy of the U determination is attained. The relationships obtained can be used in the development of a method for quantitative determination of small amounts of U in solutions.