Smartphone-Integrated Dual-Signal Imprinting Fluorescent Sensing System for Precise Recognition and Detection of Tetracycline and Oxytetracycline

Tetracycline (TC) and oxytetracycline (OTC) are commonly used antibiotics in medicine and agriculture, but their extensive use seriously endangers human health and the ecosystem. Herein, a dual-signal ratiometric fluorescent biomimetic sensor based on europium coordination polymers doped with carbon dots (Eu-CPs&CDs), incorporating molecularly imprinted polymers was developed for selective and visual monitoring of tetracyclines (TCs). The resulting Eu-CPs&CDs@MIPs sensor showed an obvious fluorescence color evolution from blue to red in the presence of TC or OTC. The blue fluorescence was quenching through the inner filter effect (IFE), while the red fluorescence (λ617) was induced by the antenna effect (AE). The smartphone-integrated imprinting protocol combined with visual intelligent detection revealed precise recognition and detection of TC and OTC, with a good linear range of 0.1–13 μmol/L and detection limits of TC and OTC reaching 17.09 and 15.33 nmol/L, respectively. By coupling F617/F423 and R/B with the concentrations of TC and OTC, binary linear regression equations for TCs fingerprinting were established, which realized the precise quantification of TC and OTC. Overall, the proposed method with good sensitivity and reliability has great application prospects for the on-site detection of pollutants in real samples.