SPECTROPHOTOMETRIC DETERMINATION OF URANIUM(VI) WITH EDDHA (ETHYLENEDIAMINE N, N'BIS O-HYDROXYPHENYLACETIC ACID)

A method for the spectrophotometric determination of uranium with EDDHA at pH 10.0 - 11.5 is proposed. The spectrum shows an absorption maximum at 253 nm. The effects of amount of reagent, acidity, time and temperature have also been studied. Beer's Law is obeyed in the range 1.83 to 43.90-mu-g U(VI) mL-1 with a photometric minimum error of 2.87%, the molar absorptivity was (6.55 +/- 0.03) x 10(3) L mol-1 cm-1. The reproducibility, precision, stoichiometry of the complex and potential interferents has been investigated. The method is more sensible than others also using chelating agents as chromogenic reagents in the u.v. region and was applied to the determination of uranium in a carnotite mineral sample.