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

Abstract

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.