Molecular Imprinting in Fluorescent Particle Stabilized Pickering Emulsion for Selective and Sensitive Optosensing of λ-Cyhalothrin

Abstract

A red luminescent europium (Eu) complex covalently modified mesoporous silica spheres (mSiO2–Eu(TTA)3Bpc; TTA, 2-thenoyltrifluoroacetone; Bpc, 2,2′-bipyridine-4,4′-dicarboxylic acid) were designed. Then the molecularly imprinted polymers combined with fluorescence sensor were first prepared via mSiO2–Eu(TTA)3Bpc stabilized Pickering emulsion polymerization, and were further applied for selective and sensitive optosensing of λ-cyhalothrin (LC). The as-prepared mSiO2–Eu(TTA)3Bpc@MIPs were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and elemental analyzer, the results demonstrated the formation of monodisperse and uniform-sized LC-imprinted spheres. Meanwhile, fluorescence spectroscopy was used to evaluation of optical stability, effect of pH, and selective and sensitive determination of LC. The fluorescent intensity of mSiO2–Eu(TTA)3Bpc@MIPs decreased in the first 5 days and then kept stable for nearly a month. Under optical conditions, mSiO2–Eu(TTA)3Bpc@MIPs were successfully applied to selectively and sensitively detect LC in water, and a linear relationship could be obtained covering the concentration range of 10–1000 μM with a correlation coefficient of 0.9986. Moreover, LC could quench the luminescence of mSiO2–Eu(TTA)3Bpc@MIPs in a concentration-dependent manner, which was best described by a Stern–Volmer-type equation.