<p>The<?tk 4?> repeated use of cooking oils led to thermal oxidation and hydrolysis, resulting in the formation of peroxidic species that may contribute to oxidative stress when consumed. The need for a rapid and peroxide-specific analytical approach encouraged the development of an electrochemical sensor based on a composite of manganese dioxide and mesoporous carbon. In this study, manganese dioxide with distinct nanostructured morphologies was synthesized and evaluated to determine the most electroactive structure for peroxide detection. Among the tested morphologies, the nanowire form produced the highest current response. The manganese dioxide-mesoporous carbon composite exhibited two linear detection ranges with sensitivities of 0.0093 and 0.0219 µA/µM, and limits of detection of 84.13 and 35.67 µM, respectively. The sensor demonstrated good selectivity, stability, and reproducibility. Its applicability was further examined using spiked cooking oil samples, including reheated oils in which only spiked peroxide was detected. These findings indicated that the manganese dioxide-mesoporous carbon interface offered a promising platform for peroxide analysis in oils and provided a basis for future development of portable systems for on-site oil quality assessment.<?tk 0?></p><?break??> Graphical Abstract <p>Electrochemical detection of peroxide using MnO₂-MPC nanocomposite</p> <p></p>