Grape Pomace Carbon Quantum Dot-Based Dual-Channel Fluorescence Sensor for Sensitive Detection of Antibiotic Residues in Food

With the rapid development of nanomaterials, carbon quantum dots (CQDs) with diverse and superior physicochemical characteristics have garnered considerable attention. In this work, we report a sustainable and green synthetic strategy for fabricating novel blue-emissive, water-dispersible CQDs utilizing grape pomace (a winemaking waste) as a renewable carbon precursor, achieving a quantum yield of 32% without requiring additional surface modification. This approach not only promotes waste valorization but also aligns with principles of environmental sustainability. The as-prepared CQDs demonstrate remarkable selectivity toward tetracycline (TC), inducing significant fluorescence quenching via the inner filter effect (IFE). Conversely, enrofloxacin (ENR) triggers notable fluorescence enhancement, predominantly governed by the surface passivation (SP) mechanism. A linear response range of 0–100 µM for TC was established and 0–100 µM for ENR, with a remarkably low detection limit (LOD) of 0.48 µM and 0.94 µM. Furthermore, the CQDs demonstrated robust performance in the quantification of TC and ENR in real-world samples, with stable analytical responses achieved within 1–60 min. Collectively, these findings underscore the potential of the CQDs as a cost-effective, facile, and highly sensitive fluorescence-based sensing platform for monitoring veterinary drug residues.