Yuxia Qi, Guanyu Li, Chanling Wei, Lijuan Zhao, Bolin Gong
In this work, a simple and selective method was successfully developed for the determination of melamine (MEL) in milk sample using magnetic surface molecularly imprinted polymer (MMIPs) as sorbent. The MMIPs has been prepared by using MEL as template molecule, methacrylic acid (MAA) as functional monomer and Fe3O4@ SiO2 as magnetic support. The polymer was characterized by means of fourier transform infrared(FT-IR) analysis, X-ray diffraction (XRD) analysis, thermogravimetric Analysis (TGA) ,scanning electron microscope(SEM) and vibrating sample magnetometer (VSM).The results demonstrated that an imprinted polymer layer was successfully coated onto the surface of modified Fe3O4 nanomaterials, resulting in a good magnetic responsibility. The UV spectrophotometry was used to demonstrate the interaction between MEL and MAA. It was found that one MELwas entrapped by two MAA molecules. Binding selectivity, adsorption capacity and the reusability for MMIPs were also evaluated in details. Results indicated the prepared MMIPs exhibited high adsorption capacity, fast binding ability and high selectivity for melamine. Detection limits for melamine were within the range of 0.15-3.00 μg/mL, which could meet the analysis of trace melamine in milk. Calibration curve was established with R of 0.9997. The limit of detection (LOD) of this new method was 15 μg/L. The obtained results revealed that the extraction recoveries of melamine from real samples were in the range of 85.6% to 104.2%. This work proposed a sensitive, rapid, reliable and convenient approach for the determination of trace melamine in complicated milk sample.
