A Sensitive Method for Electrochemical Determination of Molybdenum (VI) in Plant Foodstuff Samples Using Ni0.5Zn0.5Fe2O4 Nanocomposite Modified Carbon Paste Electrode

In the present study, a new chemically modified carbon paste electrode (CPE) is constructed for rapid, accurate, simple, highly sensitive, and selective determination of Mo (VI) using differential pulse voltammetry. The electrode was prepared using magnetic nickel zinc ferrite nanocomposite (Ni0.5Zn0.5Fe2O4), as the modifier in CPE (Ni0.5Zn0.5Fe2O4/ CPE). Mo (VI) was determined after preconcentration at the surface of the modified electrode at -0.7 V vs. Ag/AgCl. Under the optimal conditions, the linear dynamic range and limit of detection were 0.005-1.00 and 0.003 μgmL^-1, respectively. Ten successive measurements of 0.06 and 0.70 μgmL^-1 of Mo (VI) ions showed the relative standard deviation of 3.20 and 1.98 %, respectively. The reproducibility and stability of the electrode response were also studied. Investigation of the effects of different cations and anions on the determination of Mo (VI) indicated that the electrode is highly selective. Furthermore, the present method was applied to the determination of Mo (VI) in several plant foodstuff samples with satisfactory results.