Simultaneous detection of copper and lead ions using dithizone modified screen-printed electrode

The contaminant metal copper and lead ions were determined simultaneously using dithizone modified screen-printed electrode (SPE) by anodic stripping voltammetry (ASV) in the HAc-NaAc buffer solution (0.1 mol/L, pH 5.0). Copper and lead ions had sensitive anodic stripping peak at -0.18 V and -0.76 V, respectively. The optimum parameters by optimizing the conditions of the detecting method were as follows, dithizone modification quantity 3 μg, pH 5.0, electrodeposition potential -1.1 V and electrodeposition time 210 s. Under the optimum conditions, a good linear retationship was obtained between the concentration of Cu2+ and Pb2+ ranged in 1.0×10-10~1.0×10-5 mol/L and 1.0×10-10 -1.0×10-6 mol/L, respectively, with stripping peak current (RCu = 0.9991, RPb = 0.9934). The detection limits for Cu2+ and Pb2+ were of 0.35×10-10 mol/L and 0.41×10-10 mol/L, respectively. The method was simple, fast and sensitive for the determination of Cu and Pb in tea.