Ferroin is suitable as a redox indicator, as the color change is reversible, very pronounced and rapid, and the ferroin solution is stable up to 60 °C.
Ferroin serves as an indicator of oxidation reduction reactions in titrimetric analysis. Ferroin is the complex of 1,10-phenanthroline and Fe(II). It is also used as a catalyst for Belousov−Zhabotinsky reaction.
A redox indicator (also called an oxidation-reduction indicator) is an indicator which undergoes a definite color change at a specific electrode potential. ... In these systems, the metal changes oxidation state.
Oxidation/reduction (redox) indicators are colorimetric reagents which show a distinct color change at a specific electrode potential. These are all organic compounds exhibiting reversible redox reactions.
