Development of a Co3O4/rGO Modified Electrochemical Sensor for Highly Sensitive Riboflavin Detection

Abstract The monitoring of antioxidants is crucial to prevent damage caused by reactive oxygen species (ROS). In this study, we introduce an innovative electrochemical sensor tailored for detecting riboflavin (RF), a powerful antioxidant. The sensor was developed by modifying a gold electrode (AuE) with cobalt oxide (Co 3 O 4 ) and reduced graphene oxide (rGO). The resulting nanocomposite‐modified electrode (AuE/Co 3 O 4 ‐rGO) exhibited a substantial surface area of 0.41 cm 2 in the redox probe, leading to an enhanced RF peak characterized by remarkably low charge transfer resistance (1.61 KΩ) and a high exchange current density (18.6 μA/cm 2 ). Under optimized conditions, the sensor achieved a limit of detection (LOD) for RF at 1.30 μM, over a concentration range of 6.5–42.2 μM. These results highlight the sensor's potential applicability in real‐world scenarios, including the analysis of milk and pharmaceutical samples. A kinetics study revealed that the electrochemical reaction involving RF is adsorption‐controlled, emphasising the critical role of surface interactions. The modified electrode's interaction with RF significantly influences overall reaction kinetics. These findings were further supported by density functional theory (DFT) calculations and molecular simulations. Our nanocomposite‐modified electrode provides valuable insights into the atomistic interactions governing sensor performance, advancing the field of electrochemical sensing for antioxidants like riboflavin.