Pyrene-based fluorescent molecularly imprinted polymer for the rapid and selective detection of oxytetracycline based on the inner filter effect.

Oxytetracycline (OTC) residues seriously threaten human health, as they may trigger allergic responses, hepatotoxicity, and the development of bacterial resistance. Detecting OTC in samples is therefore important. This work developed a pyrene-based fluorescent molecularly imprinted polymer (Py-FMIP) for rapid and selective detection of OTC. -allyl-4-(pyren-1-yl) butanamide (Al-Py), a new alkenyl functional monomer, was synthesized from 1-pyrenebutyric acid as the raw material through a simple synthesis process. Py-FMIP was then obtained with Al-Py as a functional monomer and OTC as a template molecule. The absolute fluorescence quantum yields of Al-Py and Py-FMIP were 74.05% and 69.27%, respectively, suggesting high fluorescence performances of the two materials. The fluorescence of Py-FMIP was strongly quenched by OTC through the inner filter effect. The prepared Py-FMIP sensor responded to OTC within 1 min, with a linear detection range of 0.5-150 µM, and its detection limit was 0.05 µM S/N = 3. The prepared Py-FMIP sensor also exhibited notable selectivity toward OTC. The recoveries of the Py-FMIP fluorescent sensor ranged from 96.37% to 104.60% in milk and tap water, with relative standard deviations lower than 5.13%.