Direct spectrofluorimetric determination of microquantities of zirconium in uranium

The most suitable conditions for the direct spectrofluorimetric determination of zirconium in uranyl chloride solutions, using morin (3,5,7,2',4'- pentahydroxyflavone) as fluorimetric reagent and Na2EDTA (disodium salt of ethylenediaminetetracetic acid) as quenching reagent for the Zr-morin complex fluorescence, emphasizing the study of fluorescence quenching of the uranyl ion is presented. The intense fluorescence of Zr-morin complex in diluted inorganic acid solutions (about 2M) permits the detection of 5 x 10-4 mg Zr/1 in absence of uranium and 5 x 103 mg Zr/1 in solutions up to 50gU/1. The spectrofluorimetric detemination of zirconium content is made in 2M HCI solution, by measurement of the quenching that occurs in the fluorescence of the Zr-morin complex when in the presence of Na2EDTA. In the presence of uranium, the determination is carried out with excitation at 450 nm and emission fluorescence at 502 nm. Hafnium is simultaneously determined with zirconium. This procedure was also applied to the determination of zirconium in Zr-Zn-Mg alloys