Magnetic molecularly imprinting polymers and reduced graphene oxide modified electrochemical sensor for the selective and sensitive determination of luteolin in natural extract

The rapid and sensitive determination of luteolin was important since it was an effective antioxidant and bioactive supplement in food. For this purpose, magnetic molecularly imprinted polymer (Fe3O4@MIP) using luteolin as template was prepared, and then modified on the surface of glassy carbon electrode together with reduced graphene oxide (Fe3O4@MIP/rGO/GCE) for the sensitive electrochemical detection of luteolin. Through characterizations and adsorption experiments, Fe3O4@MIP demonstrated sphere structure with rough surface, well magnetic response in solution and better selectivity for luteolin than molecularly imprinted polymer (SiO2@MIP). After optimization of fabrication and electrochemical conditions, the Fe3O4@MIP/rGO/GCE exhibited satisfied anti-interference ability, linearity, detection limit, reproducibility and stability in detection. The linear detection range of luteolin using Fe3O4@MIP/rGO/GCE was from 2.5 pM to 0.1 μM, and the sensor could keep stable in six days. It was also successfully utilized in the determination of luteolin in lotus leaves extract with well recovery. Based on these results, the proposed electrochemical sensor Fe3O4@MIP/rGO/GCE had good prospects in evaluation of natural antioxidants.