Determination of uranyl ion by potentiometric titration using an uranyl-selective electrode

Summary A potentiometric titration of uranyl ion is described using an uranyl selective electrode based on a membrane containing a complex of UO₂-bisdi-4-(1,1,3,3-tetra-methylbutyl)phenyl phosphate] as an ion-exchanger and tritolyl phosphate as a solvent mediator. The titrations were carried out with various titrants: sodium hydroxide, potassium fluoride and sodium salts of acetate, oxalate and citrate. The equivalence points were determined by Gran's method. Good results were obtained by using sodium oxalate as a titrant for the determination of uranium in several samples of ammonium diuranate. The results were quite comparable with those obtained by X-ray fluorescence spectrometry.