Construction of an electrochemical sensor for sensitive detection of norfloxacin based on DFT and surface molecular imprinting technology

Norfloxacin (NOR) is a widely utilized fluoroquinolone antibiotic, and its residues in food present a potential risk to human health. Consequently, the development of rapid, sensitive, and selective methods for NOR detection is of paramount importance. A surface molecularly imprinted electrochemical sensor based on chitosan/polypyrrole (CS/PPy) was constructed for sensitive and selective detection of NOR. Density functional theory (DFT) accelerated selection of rational functional monomers, as well as the ratio of template molecules to monomers. The results show surface molecularly imprinted polymer (CP-MIPs) have excellent adsorption selectivity for NOR with a maximum of 286   mg/g and high imprinting factor with 2.07. The sensor exhibits good linearity ranges (0.6 ~ 30 nmol L -1 ) with a limit of detection (LOD) of 0.17 nmol L -1 , shows good selectivity, repeatability and stability. A good recovery (97.8% ~ 102.0%) is demonstrated in the detection of water, milk, and pork by adding 5 nmol L -1 or 10 nmol L -1 NOR. It provides a simple and convenient strategy for the rapid detection of NOR residues in food.