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

•Novel modified [Ru(bpy)3]2 +/Nafion®/ITO electrodes were fabricated.•The optimized [Ru(bpy)3]2 +/Nafion® ratio was 5 mg/mL in detecting lead and cadmium ions.•The optimum Nafion® volume concentration in the film was 0.4% which gave an average film thickness of 217.90 nm.•The limit of detection (LOD) was determined to be 0.007 μM (1 ppb) and 4.91 μM (552 ppb) for lead and cadmium, respectively.

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 0.007 μM (0.001 μg/mL) and 4.91 μM (0.552 μg/mL) for lead and cadmium, respectively. The optimum Nafion® volume concentration in the film was 0.4% which gave an average film thickness of 217.90 nm.