Analytical Sciences

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

Junhua LI, Fuxing ZHANG, Jianqiu WANG, Zhifeng XU, and Rongying ZENG

Department of Chemistry and Material Science, Hengyang Normal University, Hengyang, Hunan 421008, P. R. China

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.

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