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

Oxytetracycline (OTC) residues have seriously threatened 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) to rapidly and selectively detect OTC. N-allyl-4-(pyren-1-yl) butanamide (Al-Py), a new alkenyl functional monomer, was synthesized using 1-pyrenebutyric acid as the raw material with simple synthesis process. Py-FMIP was then obtained with Al-Py as a functional monomer and OTC as a template molecule. The Al-Py and Py-FMIP absolute fluorescence quantum yields were 74.05% and 69.27%, separately, suggesting the high fluorescence performances of two materials. The fluorescence of Py-FMIP was strongly quenched by OTC through inner filter effect. The prepared Py-FMIP sensor responded to OTC within 1 min, its linear detection range was 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 were 96.37%–104.60% in milk and tap water, with relative standard deviations lower than 5.13%.