Dual-emission rhodamine–carbon dot sensor for rapid monensin residue detection in poultry

The widespread use of monensin (MON) as an ionophore antibiotic in poultry production has raised significant concerns regarding residue accumulation in edible tissues, particularly given its potent cardiotoxic effects and narrow safety margins in Humans. Current analytical methods for MON detection primarily rely on expensive instrumentation, limiting accessibility for routine monitoring in resource-constrained regions with expanding poultry production. This study addresses the critical need for a cost-effective, field-deployable analytical platform by developing the first Dual-emission ratiometric fluorometric sensor specifically designed for MON residue detection in poultry tissues. The innovative sensing mechanism exploits the differential fluorescence responses of Rhodamine 6G (R6G) and red-emitting carbon dots (RCDs) upon MON interaction, where selective quenching of RCD emission (608 nm) occurs simultaneously with R6G signal enhancement (550 nm) under 525 nm excitation. This Dual-response system provides unprecedented analytical robustness through built-in internal calibration, eliminating matrix interference effects that plague conventional single-wavelength methods. The sensor demonstrated exceptional performance with linear detection ranges of 0.1–8.0 ng/mL in standard solutions and 5.0–400.0 ng/g in tissue matrices, achieving recovery efficiencies of 95.9–98.0% in muscle and 96.2–96.8% in liver samples. This platform uniquely enables real-time monitoring of MON elimination kinetics, facilitating evidence-based withdrawal period determination for specific production conditions. The methodology offers developing nations and small-scale producers an accessible compliance tool without requiring sophisticated instrumentation. Future applications include multiplex ionophore detection and portable device integration for on-site screening, potentially revolutionizing antibiotic monitoring in global food supply chains.