Construction of Electrochemical Sensor Based on FeCo₂S₄@rGO and Its Application in Detection of Lead Ion

Lead is one of the most common heavy metal pollutants in groundwater, causing serious harm to people's production and life. Therefore, it is essential to develop sensitive, stable, and highly selective detection methods for lead ions. In this study, a two-step solvothermal method was adopted to prepare FeCo2S4@rGO to detect lead. The morphology, structure and properties of FeCo2S4@rGO were characterized by scanning electron microscope and X-ray photoelectron spectroscopy. Then FeCo2S4@rGO was coated on a glassy carbon electrode to construct an electrochemical sensor by drop-coating method, and the lead ion in groundwater was detected by square wave stripping voltammetry. Finally, the influencing factors were studied to select the optimal experimental conditions. The results showed that the detection limit of the FeCo2S4@rGO sensor for lead ion was 2.78 nmol/L (S/N=3), and the detection range was 0.03-1.00 mu moIJL. In addition, the sensor had excellent selectivity and reusability, and the spiked recoveries for lead in actual groundwater samples were 95.7%-104.4%. This study was of great significance for rapid identification and early warning of lead pollution in groundwater.