Electrodeposition of gold nanoparticles and reduced graphene oxide on an electrode for fast and sensitive determination of methylmercury in fish.

Fish consumption is the main source of methylmercury (CH3Hg+) exposure for humans. In this study, gold nanoparticles and reduced graphene oxide (AuNPs-RGO) modified electrode was fabricated for determination of CH3Hg+ in fish. The AuNPs-RGO composite was synthesized by electroreduction method. The composite was characterized by scanning electron microscopy and energy dispersive spectra, X-ray diffraction and Raman spectroscopy. Electrochemical performance of the proposed sensor was studied by cyclic voltammetry, electrochemical impedance spectroscopy and differential pulse stripping voltammetry. The excellent conductivity and large surface of graphene contributed to an improvement in the voltammetric stripping signal. Under the optimized conditions, the methylmercury concentration in the range from 3 to 24μgL-1 had a good linear relation with the peak current. The detection limit of AuNPs-RGO modified electrode was 0.12μgL-1. Finally, the developed electrode was applied to detect methylmercury in fish samples, and the obtained results were in good agreement with certified values.