ZIF-8-Confined and APTES-Passivated CsPbBr3 Quantum Dots for Fluorescence Detection of Enrofloxacin Residues in Foods.

Enrofloxacin residues in foods pose potential risks to food safety and public health, creating demand for rapid, sensitive, and matrix-compatible screening methods. All-inorganic CsPbBr3 quantum dots (QDs) are promising fluorescent probes because of their strong photoluminescence, but their poor stability in polar media greatly restricts their practical use in food analysis. Herein, ZIF-8-confined and APTES-passivated CsPbBr3 QDs were developed as an ethanol-compatible fluorescent sensor for enrofloxacin detection in foods. Unlike reported CsPbBr3@ZIF-8 systems mainly used for metal-ion sensing in aqueous media, this work integrates ZIF-8-confined in-situ growth with APTES-assisted silane passivation to improve the stability and applicability of CsPbBr3 QDs in ethanol-based food extracts. ZIF-8 provided a confined microenvironment, while the APTES-derived silane layer further enhanced fluorescence stability. The sensor exhibited a distinct turn-off fluorescence response toward enrofloxacin, with a linear range of 0.1-25.0 mg·L-1 and a limit of detection of 0.058 mg·L-1, mainly attributed to electron transfer with CsPbBr3@ZIF-8. The method was successfully applied to honey, milk, fish, and shrimp samples, achieving recoveries of 85.2-106.8%. Results obtained for aquatic products showed no significant difference from HPLC analysis (p > 0.05), demonstrating the potential of this sensor for rapid enrofloxacin residue screening in complex food matrices.