Epipremnum aureum-derived Carbon Dots-based Fluorescent Sensing System for the Detection of Tetracycline in Three Types of Meat Products

To enable sensitive detection of antibiotic residues in meat products, red-emissive carbon dots (R-CDs) with dual-emission, synthesized by one step via a solvothermal method using biomass Epipremnum aureum as the carbon source, were employed to construct a ratiometric fluorescent sensor for detecting tetracycline (TC) residues in three types of meat products. The results demonstrated that the R-CDs were well-dispersed and quasi-spherical, composed of amorphous carbon cores and conjugated sp² domains, with surfaces rich in -OH, -NH₂, -COOH, and aromatic active groups. The R-CDs exhibited good fluorescence stability under the conditions of a 10-fold dilution, pH 7.0, an incubation time of 15 min, and temperatures of 15~60 ℃. Upon excitation at 410 nm, the R-CDs displayed distinct dual-emission peaks at 505 nm and 672 nm. TC selectively quenched the fluorescence at 672 nm while enhancing the emission at 505 nm, enabling a ratiometric sensing platform based on the intensity ratio (F₅₀₅/F₆₇₂). The sensor demonstrated a good linear response in the range of 0~4.00 μg/mL, with a detection limit of 0.091 μg/mL, and exhibited high selectivity toward TC. Furthermore, a semi-quantitative visual detection method was developed using smartphone-based image analysis with RGB signals, achieving a detection limit of 0.024 μg/mL within the range of 0~2.50 μg/mL. Spiked recovery tests on pork, chicken, and beef samples yielded recoveries ranging from 96.80% to 104.20%, with relative standard deviations of less than 2.41%, confirming the method’s accuracy and reliability. This study contributes to a green, sensitive, and practical strategy for the on-site, rapid, and visual monitoring of TC residues in food.