Gold nanoparticle modified screen-printed carbon arrays for the simultaneous electrochemical analysis of lead and copper in tap water

Disposable screen-printed carbon arrays modified with gold nanoparticles (AuNPs) are described. The AuNP-modified screen-printed carbon arrays, designated as AuNP-SPCE arrays, were characterized by cyclic voltammetry and electrochemical impedance spectroscopy. The AuNP-SPCE arrays display excellent electrocatalytic activity towards lead and copper. Two well-defined and fully resolved anodic stripping peaks, at 20 mV for Pb(II) and at 370 mV for Cu(II), both vs. Ag/AgCl, can be seen. Square wave anodic stripping voltammetry was used to simultaneously analyze Pb(II) and Cu(II) in their binary mixtures in tap water. The linear working range for Pb(II) extends from 10 mu g.L-1 to 100 mu g.L-1 with a sensitivity of 5.94 mu A.mu g(-1).L.cm(-2). The respective data for Cu(II) are a working range from 10 mu g.L-1 to 150 mu g.L-1 with a sensitivity of 3.52 mu A.mu g(-1).L.cm(-2). The limits of detection (based on 3x the baseline noise) are 2.1 ng.L-1 and 1.4 ng.L-1, respectively. In our perception, this array is particularly attractive because Pb(II) and Cu(II) can be determined at rather low working potentials which makes the method fairly selective in that it is not significantly interfered by other electroactive species that require higher reduction potentials.