In this work, a glassy carbon electrode (GCE) coated with poly(amidoamine) dendrimer functionalized magnetic graphene oxide (GO-Fe3O4-PAMAM) was applied for the simultaneous detection of Pb(II) and Cd(II) in environmental waters. The square wave anodic stripping voltammetry (SWASV) method was employed for the determination of target metal ions after closed-circuit mode. The effects of different experimental variables such as supporting electrolyte type, preconcentration solution pH, accumulation potential, accumulation time and concentration of dropped GO-Fe3O4-PAMAM nanocomposite were investigated and optimized. At optimal chemical and electrochemical conditions, the designed sensor showed linear voltammetric responses in the ranges of 0.4–120 μg L−1 for Pb(II) and 0.2–140 μg L−1 for Cd(II) with coefficients of determination higher than 0.99. Low detection limits of 130 ng L−1 for Pb(II) and 70 ng L−1 for Cd(II) were also achieved. Beside, possible interferents of some metal ions including Tl(I), Cu(II), Zn(II), Hg(II), Co(II), Mg(II), Ca(II), Mn(II), Ni(II), Fe(III), In(III) and Cr(III) were examined but did not cause any significant interferences. Finally, the present assay was employed for the simultaneous detection of both cations in real water samples, and the obtained results were verified by inductively coupled plasma mass spectrometry (ICP-MS) as a confirmatory method.
