Determination of lead(II) on a copper/mercury-plated screen-printed electrode

A Cu/Hg-plated screen-printed electrode (CMSPE) was developed for trace Pb(ll) determination by square-wave anodic stripping voltammetry. The intermetallic property of lead with copper in mercury was utilized to increase the sensitivity of Pb(II) detection. The calculated transfer coefficient value for the Pb(II)/Pb redox process on the CMSPE is similar to 0.5 representing the ideality of the system for Pb(II) detection. Systematic investigations were made to optimize the Cu-Hg plating condition on SPE towards the Pb(II) signals in terms of Cu/Hg ratio, plating potential, and plating time. The optimum conditions for electrochemical and square-wave parameters were also evaluated. The calibration curve was linear in the range of 0-100 ppb Pb(II) with a detection limit of 0.81 ppb (S/N = 3) for 60 s preconcentration time. The analytical utility of the CMPSE was demonstrated by applying to various water samples. (C) 2000 Elsevier Science B.V. All rights reserved.