Square-wave voltammetric stripping analysis of lead(II) at a Nafion®/copper-mercury film electrode

A novel Nafion®/copper-mercury film electrode was developed for the determination of trace Pb(II) in real samples by square-wave anodic stripping voltammetry. The preparation of the Nafion®/copper-mercury film electrode was performed by first spin-coating the Nafion® polymer on the glassy carbon electrode surface. Subsequently, an appropriate molar concentration ratio of Cu(II) to Hg(II) was plated onto the electrode. Various factors influencing the determination of Pb(II) were thoroughly investigated. Under optimal conditions, compared with a conventional Nafion®/mercury film electrode, a 4-fold increase in sensitivity can be achieved. Linear calibration curves are obtained over the 0–20 μg 1−1 range with a detection limit of 80 ng 1−1 (SN = 3) for 150 s preconcentration time. The Nafion®/copper-mercury film electrode showed good resistance to interferences from surface-active compounds and common ions. High precision is achievable, if the copper mercury film is preplated freshly before each analysis. The analytical utility of the Nafion®/copper-mercury film electrode was demonstrated by application to various water samples.