Portable Quantitative Detection of Tetracycline Antibiotics Using Molecularly Imprinted Fluorescent Test Strips

To address the challenges of insufficient selectivity, environmentally induced signal instability, and limited quantitative reliability in the on-site rapid detection of tetracycline antibiotics (TCs) in food samples, this study developed a portable quantitative detection method for oxytetracycline (OTC) based on a molecularly imprinted fluorescent test strip. The proposed platform integrates a molecularly imprinted polymer–quantum dot (MIP–QD) recognition system with digital signal processing strategies. CdTe quantum dot-functionalized OTC-imprinted fluorescent test strips were fabricated to enable specific target recognition and fluorescence response. Digital filtering, characteristic peak identification, virtual baseline correction, and peak area integration were employed to improve the stability and accuracy of fluorescence signal extraction. A quantitative model for OTC determination was established based on the fluorescence intensity ratio between the test line and control line (T/C fluorescence ratio). The developed assay exhibited high selectivity toward OTC, with a limit of detection (LOD) of 0.01 μmol/L and a linear detection range of 0.02–0.24 μmol/L. In spiked milk and honey samples, the recoveries of OTC ranged from 96.1% to 100.9% and from 96.9% to 102.4%, respectively, with relative standard deviations (RSDs) below 5%. By integrating molecular imprinting recognition, quantum dot-based fluorescence signaling, and portable digital signal analysis, the proposed method demonstrated reliable quantitative performance in complex food matrices and provides a feasible approach for the on-site rapid screening of tetracycline antibiotics.