Voltammetric Determination of In3+ Based on the Bifunctionality of a Multi-walled Carbon Nanotubes-Nafion Modified Electrode

Due to the strong cation-exchange ability of Nafion and the excellent properties of multi-walled carbon nanotubes (MWCNTs), a highly sensitive and mercury-free method of determining trace levels of In3+ has been established based on the bifunctionality of a MWCNTs/Nafion modified glassy carbon electrode (GCE). The MWCNTs/Nafion modified GCE detects In3+ in a 0.01 M HAc–NaAc buffer solution at pH 5.0 using anodic stripping voltammetry (ASV). The experimental results suggest that a sensitive anodic stripping peak appears at –0.58 V on anodic stripping voltammograms, which can be used as an analytical signal for the determination of In3+. A good linear relationship between the stripping peak currents and the In3+ concentration is obtained, covering the concentration range from 5.0 × 10–10 to 2.0 × 10–7 M, with a correlation coefficient of 0.999; the detection limit is 1.0 × 10–11 M. This proposed method has been applied to detect In3+ as a new way.