Voltammetric determination of aflatoxin B1 using a bismuth layer-gold nanoparticles modified glassy carbon electrode

This work describes the development of an electroanalytical methodology for the direct determination of Aflatoxin B1 using a surface-modified vitreous carbon electrode with a bismuth film and gold nanoparticles. Cyclic voltammetry was used to determine the electrochemical behavior of Aflatoxin B1 on the working electrode. A well-defined cathodic peak was observed in the voltammogram which is associated with the direct reduction of Aflatoxin B1, so this signal was selected as the analytical response. To maximize this response, Square Wave Voltammetry was selected as the quantitative technique; then, pulse frequency, pulse amplitude, and potential step were optimized using a Box-Behnken surface design. A calibration curve was constructed by measuring different Aflatoxin B1 standard concentrations from 1 to 200 ng L⁻¹; with the proper statistical analysis, it was found a linear range from 19.01 to 100 ng L⁻¹, with a limit of detection of 5.71 ng L⁻¹, and a sensitivity of 0.033 μA ng L⁻¹. A relative standard deviation percentage of 4.28 was obtained in the repeatability study. Finally, the proposed methodology was successfully used to analyze commercial milk samples.