Spectrophotometric determination of uranium using ascorbic acid as a chromogenic reagent

A spectrophotometric method has been developed for the determination of uranium(VI) using ascorbic acid. Uranium in the hexavalent state forms a reddish-brown coloured complex with ascorbic acid. The colour intensity of the complex is maximum at pH 4.2-4.5 and is stable for 24 hr. The absorbances of uranium(VI)-ascorbic acid complex at 360 and 450 nm are used for its quantification. Uranium in the range 8-200 microg/ml has been determined with good precision. The method allows the determination of uranium in the presence of many metal ions present as impurities. The described method is simple, accurate and applicable to uranium concentration relevant to the PUREX process and thus can be used for analytical control purposes.