Electrocatalytic determination of Cd and Pb using an -cysteine tungstophosphate self-assembled monolayer on a polycrystalline gold electrode

In this study, a novel sensitive surface based on an l -cysteine tungstophosphate-modified polycrystalline gold electrode (Au-(Cys)PW) was developed for the electrochemical detection of Cd 2+ and Pb 2+ in trace amounts. The electrocatalytic effect of this modified electrode toward Cd 2+ and Pb 2+ was evaluated by square wave voltammetry (SWV) as a sensitive method in the presence of the two analytes with bare and Au-(Cys)PW electrodes. The experimental conditions were optimized in order to evaluate the best analytical parameters of the sensor. A linear range of 0.01-0.2 μmol L −1 for both analytes and detection limits of 9.0 nmol L −1 and 4.0 nmol L −1 for Cd 2+ and Pb 2+ , respectively, were determined based on a signal-to-noise ratio (S/N) equal to 3. Reproducibility and repeatability studies were also performed, and the Au-(Cys)PW electrode was employed for the determination of Cd 2+ or Pb 2+ in an industrial wastewater sample, which revealed the potential application of the modified electrode. Constructing a sensitive electrochemical sensor based on (Cys)PW for Cd 2+ and Pb 2+ detection at the nanomolar level with remarkable selectivity.