Fluorescence quenching determination of tetracyclines based on the synergistic oxidation effect between Fe 3 O 4 nanoparticles and tetracyclines.

In recent years, tetracyclines (TCs) is a hot research topic. Herein, we report an interesting discovery using the complexation of oxytetracycline and metal ions. In this study, according to the properties of Fe 3 O 4 nanoparticles (Fe 3 O 4 NPs) as a nanoenzyme, it can be used to catalyze the oxidation of KI by H 2 O 2 to produce I 3 - , while at the same time I 3 - binds to rhodamine 6G (Rh6G) to form a conjoined particle (Rh6G~I 3 ) n , leading to a decrease in the fluorescence intensity of Rh6G. However, in the presence of TCs, Fe 3 O 4 NPs have a synergistic effect with TCs, leading to enhanced catalytic activity, as well as better selectivity compared to the activity of other reducing enzymes. Consequently,the fluorescent signal based on a resonance scattering effect between Rh6G and I 3 - is dependent on the concentration of TCs, thus achieving highly facile and robust detection of TCs. The limits of detection (LOD) of the method were 20 nM, 10 nM and 40 nM for oxytetracycline(OTC), tetracycline(TC) and chlortetracycline(CTC), respectively. Most importantly, the method can be successfully applied to the detection of TCs in milk, eggs, and honey. The recoveries of spiked samples ranged from 83.11 to 118.95%. Thus, a stable, hands-on strategy for the detection of TCs is proposed, which has potential applications in the field of food safety and environmental protection.&#xD.