A ratiometric fluorescence sensor based on Tb/UiO-66 for detecting tetracycline residues in milk

As dairy consumption increases, antibiotic residues in milk pose a serious threat to public health. Developing simple, rapid, and highly sensitive detection technologies is crucial for ensuring food safety. In this study, a novel fluorescent sensor, Tb/UiO-66, was synthesized by coordinating terephthalic acid ligands with terbium and zirconium ions (Tb 3 + /Zr 4+ ). This sensor enables ratiometric fluorescent detection of tetracycline (TC), exhibiting characteristic emission peaks at 394 nm, 490 nm, and 594 nm. TC quenches the emission of UiO-66 at 394 nm via the inner filter effect (IFE) and quenches the fluorescence at 490 nm through coordination with Tb 3+ . The sensor, based on the F 394 /F 490 ratio, achieves a linear range of 10–90 μg/mL and a detection limit of (LOD)0.097 μg/mL (3σ). In real milk samples, recovery rates ranged from 95.87 % to 102.44 %, with a relative standard deviation below 2.88 %. This fluorescent sensor features a simple design, rapid response, and high sensitivity, establishing a reliable platform for assessing antibiotic contamination in food safety.