Utilizing 1,10–Phenanthroline Ligand Effect in Estimation of Cobalt (II) and Simultaneous Estimation of Cobalt (II) and Iron (II) with Cerium (IV)

Transition metals have multiple oxidation states separated by a finite potential value. A redox reaction between a transition metal or a mixture of transition metal ions with an oxidant is feasible provided their reduction potential are sufficiently different and lower than the reduction potential of oxidant concerned. Since complexation modifies potential of redox systems involving metal ions, this phenomenon has a potential capacity for the development of new titrimetric methods of analysis .While potentiometric titration of cobalt (II) and simultaneous potentiometric titration of cobalt (II) and iron (II) with cerium (IV) is not spontaneous due to a mismatch of their reduction potentials. Complexation with 1,10 phenanthroline ligand in the pre step modifies potential of both the ions thereby making an otherwise not spontaneous and interfering reaction feasible.