Extraction and spectrophotometric determination of uranium(VI) with N-phenylcinnamohydroxamic acid

Uranium(VI) reacts with N-phenylcinnamohydroxamic acid to form an orange-yellow complex in the pH range 5.5-8.5. The orange-yellow complex, having the composition of 1 : 2 (metal : ligand), is quantitatively extractable into ethyl acetate. The spectrum of the complex exhibits a maximum absorption at 400 nm with a molar absorptivity of 6500 M-1.cm(-1). The coloured system obeys Beer's law in the concentration range 2-40 mu g.ml(-1) of uranium(VI). The photometric sensitivity of the colour reaction is 0.037 mu g.cm(-2) of uranium(VI). Most of the common ions do not interfere and the method has been found to be simple, precise, and free from the rigid control of experimental conditions. The method has been applied to the determination of uranium in synthetic matrices and potable water.