Determination of Lead by Square Wave Anodic Stripping Voltammetry Using an Electrochemical Sensor

A novel electrochemical assay for lead (Pb2+) detection was developed in this study, involving the use of screen-printed electrodes (SPEs). The sensor was used with selected supporting electrolytes in conjunction with square wave anodic stripping voltammetry (ASV) to study the redox characteristics of lead. Good response currents were obtained using a supporting electrolyte comprising acetate buffer pH 5.0 with 0.5 mol L-1 NH4Cl. Without a deposition process, the anodic peaks for higher lead concentrations (ranging from 0.7 to 10 mg L-1) were sharp and symmetrical on the bare electrode surface. Optimal ASV conditions were obtained with a well-defined stripping peak for 200 mu L deposition solution volumes, a deposition potential of -1.2 V for Ag/AgCl, and a deposition time of either 300 or 400 s. Under optimal conditions, a calibration curve ranging from 6.25 to 500 mu g L-1 was obtained for lead determination. Furthermore, the performance of a Hg-free sensor for Pb2+ determination was compared with that of a Hg-coated electrode, and the detection limits were approximately 0.9 - 1.5 mu g L-1.