Determination of Cd2+ and Pb2+ by polyindole/Mn2O3 nanocomposite and polyindole/Mn2O3/polyaniline nanofibers modified glassy carbon electrode

In this paper, the surface of the glassy carbon electrode was modified by polyindole (PIN)/Mn2O3 nanocomposite and PIN/Mn2O3/polyaniline (PANI) nanofibers and electrochemical behavior toward the sensing of Cd2+ and Pb2+ was investigated using differential pulse anodic stripping voltammetry. The amount of (PIN)/Mn2O3 nanocomposite was varied to find the best performance. In addition, cyclic voltammetry of ferrocyanide was used to describe the behavior of modified electrodes and the diffusion coefficient for PIN/Mn2O3 and PIN/Mn2O3/PANI samples containing 5%w/w (PIN)/Mn2O3 nanocomposite was 8.05 x 10(-7) and 1.29 x 10(-6) cm(2) s(-1), respectively. The synergistic effect of PANI and PIN/Mn2O3 in nanofibers structure enhances the accumulation efficiency and the charge transfer rate of metal ions. Under the optimal conditions, PIN/Mn2O3/PANI nanofibers modified electrode showed good linear relationships for Cd2+ and Pb2+ in a range of 0.05-450 mu g L-1, with the detection limit of 0.05 and 0.02 mu g L-1 for Pb2+ and Cd2+, respectively. The linear range and detection limit for PIN/Mn2O3 nanocomposite modified electrode was 1-200 mu g L(-1)and 9.85 and 10.72 mu g L-1 for Cd2+ and Pb2+, respectively.