Determination of plutonium by secondary coulometric titration with internally generated iron(II)

Abstract

Determination of plutonium by secondary coulometry involving the controlled potential technique for the generation of an iron(II) mediator, is reported in Part I.* In this paper, the same determination is reported using constant current coulometry for the generation of the mediator, and zero current potentiometry for end-point detection. The factors affecting the current efficiency, viz. current density and supporting electrolyte composition have been checked in order to define the appropriate conditions for obtaining 100% current efficiency. The original method of Carson et al. suffers from the disadvantage that it involves complicated sample treatment. Introduction of perchloric acid treatment as a method for the oxidation of plutonium and the pretitration of the supporting electrolyte to the end-point potential prior to sample addition, have considerably helped improve the precision and accuracy of the method. Exhaustive analytical data are reported covering plutonium quantities ranging from 25 micrograms to 5 milligrams, which establishes the scope of the method.