Voltametric and impedimetric determination of NTO explosive on a nanostructured TiO۲/carbon nanotube composite electrode

An electrochemical oxidation route was developed for sensitive and selective assay of nitrotriazolone (NTO), an insensitive explosive, on a multi-walled carbon nanotubes (MWCNTs)/TiO۲ nanocomposite paste electrode, to prevent the analytical interference of various reducible energetic compounds. The electrochemical behavior of NTO on the modified electrode was studied in detail by adsorptive stripping voltammetry, electrochemical impedance spectroscopy (EIS), chronocoulometric and chronoamperometry techniques at pH range of ۲.۰-۱۰.۰. Various kinetic parameters such as transfer electron number, transfer proton number and heterogeneous rate constant and diffusion coefficient constant of NTO were calculated, and various experimental parameters were also optimized. Under the optimal conditions the calibration curve has two linear dynamic range of ۱.۰-۲۵.۰ and ۵۰.۰-۲۰۰.۰ μM with detection limit of ۰.۲ μM and a precision of <۳%. Moreover, the fabricated sensor presented high selectivity and long-term stability. This electrochemical sensor was further applied to determine NTO in real soil and ground water samples, and it showed great promise for simple, sensitive, and quantitative detection of this explosive.

Keywords:

Nitrotriazolone , Explosive , Carbon nanotubes , TiO۲ nanoparticles , Voltammetry