Synthesis of kaolinite/magnetic molecularly imprinted polymers for solid phase extraction of chlorpyrifos

Chlorpyrifos is a highly toxic organophosphate pesticide that is widely used in global agriculture and household applications. It persists in the environment in, for example, rivers, lakes and the soil. A simple way to detect chlorpyrifos is by the use of molecularly imprinted polymers (MIP), but MIPs lack the capacity for phase separation. Magnetic molecularly imprinted polymers (MMIPs) have attracted attention for the detection of organic molecules. In this study, Fe3O4 magnetic nanoparticles, known as superparamagnetic iron oxide nanoparticles, were synthesized with kaolinite. Methacrylic acid is encapsulated as a functional group to obtain a MIP structure for the detection of chlorpyrifos. The crosslinker and initiator used in this work were ethylene glycol dimethacrylate and azobisisobutyronitrile, respectively. The morphology, chemical bonding and crystal structure as well as magnetic properties of the synthesized MMIPs were characterized through field emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffractometry and vibrating-sample magnetometry, respectively. Finally, the absorption and removal of chlorpyrifos from the synthesized MMIPs was confirmed by high-performance liquid chromatography.