Determination of Lead and Cadmium in Water Samples by Adsorptive Stripping Voltammetry Using a Bismuth film/1-Nitroso-2-Napthol/Nafion Modified Glassy Carbon Electrode

The application and validation of a glassy carbon electrode modified with Nafion, 1-nitroso-2-naphthol and bismuth film (GC/NF-NN/BiFE) was studied using adsorptive stripping voltammetry (AdSV) for the determination of Pb2+ and Cd2+ in tap water. The parameters studied and optimized were pH, 1-nitroso-2-naphthol concentration (C-NN), Nafion concentration (C-NF), adsorption potential (E-acc) and adsorption time (t(acc)). Optimal conditions were pH 4.5 (acetate buffer solution 0.10 mol L-1); E-acc: -1.30 V; t(acc): 120 s; C-NN : 0.10% w/v, C-NF: 0.50 wt %. The detection and quantification limits were 0.08 and 0.29 mu g L-1 for Pb2+ and 0.07 and 0.24 mu g L-1 for Cd2+, with a linear range of 10 to 70 mu g L-1. Certified reference material (ICP Multi Element Standard) and synthetic samples were determined to validate the methodology, with satisfactory results. The stripping voltammetry method was tested on tap water.