Rational engineering of Ag-doped reduced graphene oxide as electrochemical sensor for trace mercury ions monitoring

Abstract

Food safety has aroused increasing public concerns because it is closely related to human health. As a common pollutant, mercury ions (Hg2+) can cause an enormous menace to human health even at very low fouling level. Herein, we designed a three-dimensional reduced graphene oxide (rGO) doped by silver nanoparticles (Ag-rGO), which could be employed as an effective sensing interface to electrochemically detect Hg2+. By characterization with scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD), we confirmed that the Ag-rGO composites had multiple fold structures. After incubation with Hg2+, an obvious electrochemical signal enhancement was observed, which could be applied to detect the low level of Hg2+. The sensor based on Ag-rGO exhibited a low detection limit of 0.0049 μg/L of Hg2+ due to its multiple folds structure providing a large electrochemical active area and facilitating the electron transfer. Significantly, this proposed sensor was successfully used to evaluate the amount of Hg2+ in fish and human blood samples with acceptable results. This sensing strategy showed excellent performance for Hg2+ detection in food and clinical-related systems, which is of great significance for safeguarding food safety and human health.