Impedimetric and Stripping Voltammetric Detection of Sub-Nanomolar Amounts of Mercury at a Gold Nanoparticle Modified Glassy Carbon Electrode

A glassy carbon electrode (GCE) modified with gold nanoparticles (GNPs) was used for the determination of sub-nanmolar amounts of mercury in water samples using differential pulse stripping voltammetry (DPSV) and electrochemical impedance spectroscopy (EIS). The GNPs/ GCE electrode revealed a significant improvement for mercury detection compared with the unmodified GCE. Under the optimized experimental conditions, the modified GNPs/GCE revealed broad linear ranges of 1 to 500 nM (LOD = 0.1 nM) and 10–50 pM (LOD = 0.05 pM) for DPSV and EIS, respectively. The limits of detections obtained are much below the corresponding guideline value from the World Health Organization (WHO). The proposed DPSV method was successfully applied to the analysis of mercury content of tap water samples.