Determination of submicrogram quantities of iron(III) by a catalytic polarographic method

Abstract

A simple and sensitive polarographic method has been developed for the determination of submicrogram quantities (0.01–0.16 μg/ml) of iron('III) based on the catalytic polarographic reduction of bromate in presence of resacetophenone isoniazid hydrazone. A 200-fold ratio of Mg 2+, Ca 2+, Cr 3+, Mn 2+, Co 2+, Ni 2+, Zn 2+, Al 3+ to Fe 3+ does not interfere. However, Cu 2+ and Cd 2+ interfere if they are present in more than 20-fold ratio to Fe 3+. Ti 4+, V 5+, Mo 6+ and W 6+ interfere even at 5-fold ratio. There is no interference from F −, Cl −, Br −, I −, SO 2− 4, NO − 3 or NO − 2 even when present in large excess, but EDTA, CN −, SCN −, C 2O 2− 4, citrate and tartrate suppress the wave to a marked extent.