Determination of microgram level of iron in PuO₂, by controlled potential coulometry in presence of selective complexing agent

A new method has been developed and standardized for quantification of microgram level of iron present in PuO₂. Accurate estimation of iron was absolutely necessary for accurate estimation of plutonium by controlled potential coulometry. This was achieved by modification of the coulometric method at fixed potential involving addition of 1,10-phenanthroline which selectively complexes Fe(II), thereby shifting its potential and preventing it from participation in Pu analysis. During reduction both iron and plutonium were reduced. But when Fe(II) was complexed, it did not participated in oxidation i.e only plutonium was oxidized. Difference of the reduction and oxidation reading was used for quantification of iron. Plutonium solution of known concentration was analyzed after spiking with iron for validation of the method