Spectrophotometric determination of uranium(VI) with 2-(3,5-dibromo-2-pyridylazo)-5-diethylaminophenol in the presence of anionic surfactant

A highly sensitive method for spectrophotometric determination of uranium has been devised. The method is based on formation of a red-violet 1:2 (metal:ligand) complex from the reaction of uranium(VI) with 2-(3,5-dibromo-2-pyridylazo)-5-diethylaminophenol in the presence of an anionic surfactant sodium lauryl sulphate. Its molar absorptivity is found to be 9.1 x 104 l. mole-1.cm-1. The absorbance is constant in the range pH 8.4 to 9.9. Beer's law is obeyed for 0 to 1.4 μg/ml concentrations of uranium. In the presence of DCTA the method is selective for uranium, and can be used for the determination of trace amounts of uranium in water samples. (author)