VOLUMETRIC AND SPECTROPHOTOMETRIC MICRODETERMINATION OF CERIUM(III), THORIUM(IV) AND URANIUM(VI) IN SOME CHELATES OF 3-ACETYL-1,5-DIARYLFORMAZANS AND 3-CYANO-1,5-DIARYLFORMAZANS

The title chelates are analysed through their oxidative destruction ei ther by the Kjeldahl method or more rapidly by the oxygen flask method , followed by the microdetermination of the cations by suitable spectr ophotometric methods besides a parallel conventional volumetric confir mation methods. Ce-III is determined as the yellow formaldoxime comple x measured at 400 nm in the range 0-20 ppm, Volumetrically, it is oxid ised to Ce-IV, then reacted with FeSO4, and the excess of which is bac k-titrated with KMnO4. Th-IV is determined as the arsenate III complex measured at 660 nm in the range 1-25 mu g/25 ml. A parallel complexom etric titration using xylenol orange as indicator is performed. U-VI i s determined as its PAN complex at 555 nm in the range 1-20 ppm. A com plexometric titration at pH 4.4 in isopropanol containing medium using PAN also as indicator, is parallely done, The results are within the acceptable limits.