Preparation of Molecularly Imprinted Composites Initiated by Hemin/Graphene Hybrid Nanosheets and Its Application in Detection of Sulfamethoxazole

Molecularly imprinted polymers (MIPs) exhibit high selectivity resulting from imprinted cavities and superior performance from functional materials, which have attracted much attention in many fields. However, the combination of MIPs film and functional materials is a great challenge. In this study, hemin/graphene hybrid nanosheets (H-GNs) were used to initiate the imprinted polymerization by catalyzing the generation of free radicals. Thus, MIPs using sulfamethoxazole as the template was directly prepared on the surface of H-GNs without any film modification. Most importantly, the template could be absorbed on the H-GNs to enhance the number of imprinted sites per unit surface area, which could improve the selectivity of MIPs film. Thus, the composites could exhibit high adsorption capacity (29.4 mg/g), imprinting factor (4.2) and excellent conductivity, which were modified on the surface of electrode for rapid, selective and sensitive detection of sulfamethoxazole in food and serum samples. The linear range was changed from 5 μg/kg to 1 mg/g and the limit of detection was 1.2 μg/kg. This sensor was free from interference caused by analogues of sulfamethoxazole, which provides a novel insight for the preparation of MIPs-based sensor and its application in food safety monitoring and human exposure study.