Fabrication of dual-emission molecularly imprinted fluorescent probe for high-selectivity tetracycline tracing detection utilizing differential discrimination tactic.

Tetracycline (TC) overuse in clinical treatment and livestock breeding leads to persistent residues in animal-origin foods, severely endangering food safety and public health. Conventional chromatographic TC detection approaches suffer from expensive instruments and tedious preprocessing, while single-signal fluorescent probes are vulnerable to environmental disturbance and insufficient anti-interference capacity. Herein, an integrated molecularly imprinted ratiometric fluorescent composite (rCDs&NH2-MIL-53(Al)@MIPs) was constructed via a one-pot sol-gel route for sensitive TC measurement. Blue-luminescent NH2-MIL-53(Al) matrix was in-situ loaded with red-emitting carbon dots (rCDs), followed by coating a molecular template-imprinted silica layer to build dual self-calibration emission signals at 435 nm and 585 nm. Under optimized experimental parameters, the fluorescence ratio F435/F585 displayed a favorable linear response toward TC within 0-400 μM, with an ultralow limit of detection of 2.4 nM. The composite possesses outstanding selectivity, recyclability and long-term stability. A differential calibration strategy based on parallel non-imprinted polymer (NIP) tests was adopted to thoroughly eliminate non-selective interference. Practical quantification in spiked milk samples yielded satisfactory recoveries ranging from 86.36% to 97.94%, verifying its reliability for real food matrix analysis. This study delivers a stable, highly sensitive sensing tool for trace TC quantification and diversifies the preparation approaches of MOF/carbon dot dual-emission imprinted sensors in food safety testing.