Few-layer Binder Free Graphene Modified Mercury Film Electrode for Trace Metal Analysis by Square Wave Anodic Stripping Voltammetry

摘要

A binding agent free graphene modified glassy carbon electrode in combination with an in situ platedmercury film electrode (Gr-GC-HgFE) was used as a highly sensitive electrochemical platform for the2+ 2+ 2+ determination of Zn , Cd and Pb in 0.1 M acetate buffer (pH 4.6) by square-wave anodic strippingvoltammetry (SWASV). Instrumental parameters such as deposition potential, deposition time andelectrode rotation speed were optimized. The Gr-GC-HgFE sensing platform exhibited improvedsensitivity for metal ion detection, in addition to well defined, reproducible and sharp stripping signals. Two linear calibration curves ranging from 0 0 g L and 0 60 g L were identified yielding 2+ 2+ 2+ detection limits of 0.08 g L , 0.05 g L and 0.14 g L for Zn , Cd and Pb , respectively, for 2+ 2+ 2+ simultaneous analysis and 0.04 g L , 0.11 g L and 0.14 g L for Zn , Cd and Pb ,respectively, for individual analysis when using a deposition time of 120 s. For practical applicationsrecovery studies using tap water samples spiked with target metal ions gave recoveries within 10% ofthe spiked amount. Much better recoveries were obtained for the individual analysis in comparisonwith simultaneous analysis.