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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 μg.L to 100 μg.L with a sensitivity of 5.94 μA.μg.L.cm. The respective data for Cu(II) are a working range from 10 μg.L to 150 μg.L with a sensitivity of 3.52 μA.μg.L.cm. The limits of detection (based on 3× the baseline noise) are 2.1 ng.L and 1.4 ng.L, 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. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

A glassy carbon electrode was modified with gold hierarchical dendrites (Au HDs) by one-step electrodeposition in the presence of cytosine, which plays an important role in the formation of the Au HDs. This approach is simple, fast, feasible, controllable, without any seed, template, or surfactant. The modified electrodes were used for the simultaneous determination of Pb and Cu by square wave stripping voltammetry. The peak currents show good linear relationship with concentrations of Pb and Cu in the range of 5.0 to 15.0 μM. The recoveries of the spiked water samples are in the range of 94.0 %-107.4 % for Pb and Cu, and their relative standard deviation are in the range of 2.7 %-4.3 % for Pb and Cu, respectively ( n = 3). [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]