Computer-aided design of magnetic dummy molecularly imprinted polymers for solid-phase extraction of ten phthalates from food prior to their determination by GC-MS/MS

摘要

Magnetic dummy molecularly imprinted polymers (MDMIPs) were prepared by combining the surface imprinting technique with computer simulation for selective recognition of phthalate esters (PAEs). A computational study based on the density functional theory was performed to evaluate the template-monomer geometry and interaction energy in the prepolymerization mixture. The MDMIPs were characterized by transmission electron microscopy, scanning electron microscopy, vibrating sample magnetometry, X-ray diffraction, and Fourier transform infrared spectroscopy. They exhibited (a) high saturation magnetization of 53.14 emu g(-1) (leading to fast separation), and (b) large adsorption capacity, fast binding kinetics, and high selectivity for PAEs. Subsequently, a molecularly imprinted solid-phase extraction procedure followed by GC-MS was established for selective extraction and determination of 10 PAEs in food samples. Under the optimal experimental conditions, the response (peak area) was linear in the 0.5-100 ng mL(-1) concentration range. The limits of detection ranged from 0.15 to 1.64 ng g(-1). The method was applied to the determination of PAEs in spiked real samples. The recoveries for 10 PAEs from various foods were in the range of 73.7%-98.1%, with relative standard deviations of 1.7%-10.2%.