Electrochemical sensors based on multi-walled carbon nanotube-Nafion™ nanocomposite film for determination of heavy metals and hydrogen peroxide

A nanocomposite film of multi-walled carbon nanotubes (MWNTs) with Nafion™ is prepared by cast deposition on glassy carbon electrodes (GCE). The morphologies of the MWNTs and MWNTs/Nafion™ modified electrode are characterized by transmission electron microscopy (TEM) and atomic force microscopy (AFM). The MWNTs are cylindrically shaped and uniform with a diameter in the range of 40 - 60 nm. The MWNTs/Nafion™ composite film is cast homogeneously onto GCE. Well-defined voltammetric responses are observed for the Fe(CN)₆^4-/Fe(CN)₆^3- redox system in aqueous 0.1 M KCl on the MWNTs/Nafion™ modified electrode. The anodic stripping response for Cd metal from a solution of 1 to 4 μM in aqueous 0.1 M acetate buffer solution is demonstrated. The amounts of hydrogen peroxide and the heights of amperometric response of this sensor vary proportionately. The results indicate that the electroanalytical nanocomposite film composed of MWNTs and Nafion™ is highly sensitive and suitable for potential electrochemical sensor applications.