Highly sensitive [Ru(bpy) 3 ] 2+ /Nafion® modified indium tin oxide-based sensor for heavy metal detection

Indium tin oxide-coated glass substrates were modified with tris (2,2′-bipyridyl) ruthenium (II) dichloride hexahydrate [Ru(bpy)3]2+/Nafion® solution via dip-coating. The Nafion®—[Ru(bpy)3]2+ ratio was varied to optimize the sensitivity of the modified electrodes in detecting lead (Pb2+) and cadmium (Cd2+). The surface morphology of the deposited thin film was characterized by scanning electron microscopy (SEM). The lowest concentration detected was 0.007μM (0.001μg/mL) and 4.91μM (0.552μg/mL) for lead and cadmium, respectively. The optimum Nafion® volume concentration in the film was 0.4% which gave an average film thickness of 217.90nm.