A KINETIC SPECTROPHOTOMETRIC METHOD FOR SIMULTANEOUS DETERMINATION OF URANIUM, IRON AND VANADIUM WITH A STOPPED-FLOW TECHNIQUE

A kinetic spectrophotometric method for simultaneous determination of components of a ternary mixture is proposed. A procedure for simultaneous determination of uranium(IV), iron(II) and vanadium(IV) is established, based on the inductive effect of them on chromium(VI)-iodide reaction in weak acidic medium. The recation was monitored with the stopped-flow spectrophotometric technique by using I3--starch complex as indicator. The calibration graphs are linear for 0-3.6 mug ml-1 U(IV), 0-2.8 mug ml-1 Fe(II) and 0-2.5 mug ml-1 V(IV). Most foreign ions, except antimony(III) and titanium(III), do not interfere with the determination. Uranium, iorn and vanadium contents in a phosphate ore were determined with the proposed method, and the results are satisfactory.