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.