Facile Eco‐Friendly Hydrothermal Synthesis of Carbon Dots From Abroma Augusta Linn Bark for Detection of Diafenthiuron Residue in Fruits and Alluring Antibacterial Application

ABSTRACT Consumption of fruits such as mango, grape, cherry, apple, and tomato containing excessive diafenthiuron (DFU), a broad‐spectrum insecticide, poses serious risks to human health. Therefore, reliable detection of DFU residue is crucial to mitigate the ecological security and food safety concerns. In this study, a cost‐effective hydrothermal method was employed to synthesize Abroma augusta Linn bark‐derived carbon dots (AACDs), which serve as a fluorescent (FL) sensor for the detection of DFU of concentration 0–120 µM, with a remarkably low limit of detection (LOD) 0.006 µM. The formation and physicochemical characteristics of AACDs were verified by UV–vis, FL, FT‐IR, DLS, PXRD, TCSPC, AFM, XPS and TEM analysis. The AACDs were successfully applied to detect DFU residue in fruits. Mechanistic investigations revealed that the detection process operates via static FL quenching. In addition, the antibacterial activity of AACDs was analyzed against Gram‐negative Klebsiella pneumoniae, Escherichia coli , as well as Gram‐positive Bacillus subtilis and Staphylococcus aureus bacteria. The result demonstrated a notable inhibitory effect with very low minimum inhibitory concentrations (MICs) on the mentioned bacteria, indicating the material as an efficient antibacterial agent. Hence, this investigation explores an effective unified and versatile platform that integrates sensitive DFU detection and antibacterial activity.