Portable and decentralized electrochemical sensor based on rGO-Cu-Au ternary nanocomposites for ofloxacin detection in environmental water matrices

The persistence of fluoroquinolone antibiotics like ofloxacin (OFL) in aquatic systems leads to emergence of antimicrobial resistance (AMR) and need better technology to monitor its effects on the environment/health. The implementation of real-time and decentralized monitoring systems remains constrained due to their dependency on slow and resource-intensive technique. To overcome these challenges, an electrochemical platform based on ternary nanocomposites of reduced graphene oxide-copper-gold (rGO-Cu-Au) has been developed. The integration of rGO provides a large surface area and high electrical conductivity, while Cu nanoparticles contribute electrocatalytic activity; AuNPs further stabilize the interface and enhance charge transfer through strong metal-support interactions. The XRD, FTIR, Raman spectroscopy, XPS and FESEM analysis showed that the ternary system formed successfully through strong bonds between its components. Under the optimized differential pulse voltammetry (DPV) conditions, the sensor achieved a detection limit of 1.2 µM with linearity in range of 0-20 µM, with specific selectivity for OFL over other antibiotics. Validation in tap water and wastewater produced satisfactory recoveries across multiple spiked concentrations (n = 3 replicates per level). The resulting sensing architecture enables rapid, on-site detection of OFL, offering a practical alternative to conventional laboratory-based monitoring approaches.