A Tb (Ⅲ) Coordination Polymer Based on 5-(2-(Pyrazole-1-yl) Pyridine-5-yl) Terephthalic Acid and Its Visual Detection of Quinolone Antibiotics

The abuse of quinolone antibiotics in the medical and livestock industries potentially causes environmental accumulation that may impair ecological stability. Based on the organic ligand 5-(pyrazole-1-yl) pyridine-5-yl) terephthalic acid (H₂PPIPA), a terbium(III) complex, [Tb(HPPIPA)(PPIPA)(H₂O)]ₙ (complex <b>1</b>), was synthesized via solvothermal reaction with Tb(NO₃)₃·6H₂O. Luminescence studies revealed that complex <b>1</b> functions as a turn-on fluorescent probe for the selective detection of ofloxacin (OFX), levofloxacin (LFX), and norfloxacin (NFX), with detection limits of 27.9, 17.1, and 8.0 nM, respectively. Owing to its high selectivity and anti-interference capability, the complex was successfully applied for the determination of OFX and LFX in milk samples. Furthermore, a test strip impregnated with complex <b>1</b> enabled naked-eye fluorescence detection of OFX, LFX, and NFX under 254 nm UV light. Additionally, a fluorescence sensing film fabricated from complex <b>1</b> exhibited excellent recyclability, allowing for at least seven consecutive detection cycles without significant signal loss. This study innovatively designed and synthesized a novel Tb(III)-based coordination polymer fluorescent probe utilizing an original ligand scaffold, achieving the first reported visual detection of quinolone antibiotics with fluorescence test strips and agar films.