Square wave anodic stripping voltammetric determination of Cd and Pb ions at a Bi/Nafion/thiolated polyaniline/glassy carbon electrode

A glassy carbon electrode modified with Bi, Nafion and 2-mercaptoethanesulfonate (MES)–tethered polyaniline (PANI) was applied to sensitively detect Pb2 + and Cd2 + by square wave anodic stripping voltammetry. The PANI–MES interaction was examined by quartz crystal microbalance and Fourier transform infrared spectrophotometry. The electrode modification of thiolated PANI exhibits a higher analytical sensitivity versus that of pristine PANI, because the coordination of Pb2 + and Cd2 + with S atoms in the thiolated PANI film can improve their preconcentration efficiencies. Under optimum conditions, the linear calibration curves ranged from 0.1 to 30 μg L− 1 for Pb2 + and 0.1 to 20 μg L− 1 for Cd2 +, with limits of detection (S/N = 3) of 0.05 μg L− 1 for Pb2 + and 0.04 μg L− 1 Cd2 +, respectively, after their preconcentration at − 1.2 V vs. SCE in pH 4.0 acetate buffer containing 200 μg L− 1 Bi3 + for 5 min. This method was successfully applied for analyses of Pb2 + and Cd2 + in real water samples.

► Stripping electroanalysis of Pb2+ and Cd2+ using thiol-ene chemistry of polyaniline. ► Sub-ppb limit of detection of Pb2+ and Cd2+. ► Examination of the polyaniline thiolation by quartz crystal microbalance and FT-IR.