COLORIMETRIC DETERMINATION OF ZIRCONIUM IN THE PRESENCE OF PLUTONIUM AND URANIUM WITH ALIZARIN REDS

摘要

Zirconium can be determined colorimetrically in the presence of plutonium and uranium by the formation of a zirconium-alizarin red-S complex which absorbs at 525 mu. The acid concentration of solutions taken for analysis must be greater than 2 M to prevent hydrolysis of zirconium, but the solu¬tion in which the zirconium alizarin red-S complex is formed must be 0.15-0.25 M due to a decrease of absorbance at higher acid concentrations. Up to 6 mg of plutonium and even greater amounts of uranium (200 mg) per 25 ml of solution may be present provided mercaptoacetic acid is added to reduce the plutonium to the tripositive oxidation state. Although the colorimetric determination of zirconium in the presence of plutonium and uranium is not as precise as other quantitative techniques, the method is readily adaptable to radioactive glovebox operations.