Abstract: The U_3O_8 sample is dissolved in nitric acid and uranium is removed by ex-traction with TBP-carbon tetrachloride three times. The aqueous solution is evapo-rated to dryness with perchloric acid and the residue is dissolved in 5 ml mixturecontaining 0.05 mol/l perchloric acid and 0.03 mol/l tartaric acid. The Pb isdetermined by square wave anodic stripping voltammetry in the range -0.5～0.15 V (vs. S. C. E.) with a peak potential at -0.376 V. The solution isfurther treated with ammonium hydroxid to make the pH about 9.5. The Fe isdetermined by square wave cathodic voltammetry in the range -1.30～-1. 65 Vwith a peak potential at -1. 426V. Simultaneous determination of 1-0. 01ppm ofthe above elements are possible.