An Electrochemical Sensor Based On 2D Graphitic-phase Carbon Nitride Nanosheets Doped With FeP-C Nanospheres for the Detection of Cu²⁺ in Meat

Copper ions (Cu²⁺) are commonly present in meat and their presence has been shown to affect human health. Therefore, there is an urgent need to develop a rapid and sensitive method for detecting trace amounts of Cu²⁺. In this study, we developed an electrochemical sensor based on g-C₃N₄@FeP-C/GCE for the detection of Cu²⁺ in beef and the beef liver. The incorporation of FeP-C into the g-C₃N₄ framework enhances the catalytic performance of the sensor through strong electrostatic interactions between the positively charged metal cations in FeP-C and the negatively charged nitrogen in g-C₃N₄. The combination of g-C₃N₄ (graphitic carbon nitride) and FeP-C (Fe₃O₄ phosphorylated doped carbon) resulted in the generation of additional active sites for the sensor, further improving its catalytic performance. The morphology and internal structure of the nanocomposite were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The developed sensor exhibited sensitive Cu²⁺ detection in meat, with a limit of detection (LOD) of 16.7 nM and a linear range of 0.05—150 μM. Furthermore, the method demonstrated satisfactory recoveries in beef and beef liver, with a relative standard deviation (RSD) not exceeding 5%.