A sensitive and selective spectrophotometric method is proposed for the rapid determination of uranium using tris-[2,4,6-(2-hydroxy-4-sulpho-1-naphthylazo)]-s-triazine, trisodium salt (THT). An addition of dilute solution of uranyl ions to the aqueous solution of THT resulted to form a water soluble dark red colored complex absorbing maximum at 540 nm in the pH range 3.8-6.0. Beer’s law is valid over concentration range 0.0-6.2 ppm with molar absorptivity and Sandell’s sensitivity of 6.1x104 L mol-1cm-1 and 0.0039 µg cm-2, respectively. The molar composition of the complex is 2:3 (M:L) as determined by Job’s method of continuous variations. The tolerance limits for interfering ions have been investigated. All variables have been studied in order to optimize the reaction conditions. The efficiency of the proposed method is shown by the successful determination of traces of uranium in some synthetically made samples of ores.
Spectrophotometry, Uranium, THT, Triazine