Highly sensitive electrochemical sensing of norfloxacin by molecularly imprinted composite hollow spheres

Poly (3,4-ethylenedioxythiophene) (PEDOT)-based molecularly imprinted electrochemical sensors have attracted widespread attention for monitoring contaminants in food and the environment. However, there are still problems such as poor hydrophilicity, easy agglomeration, and low selectivity in its preparation. In this work, a novel molecularly imprinted composite hollow sphere was prepared by a molecular imprinting technique using nitrogen-doped hollow carbon spheres as matrix material, and PEDOT and poly(methacrylic acid) as monomers. The selective binding capabilities and mechanism of the material to norfloxacin (NOR) were systematically investigated. Then the material-based sensor was constructed, and its electrochemical detection performance toward NOR was thoroughly studied. The sensor exhibited a wide linear range (0.0005-31 μM), a low detection limit (0.061 nM), satisfactory immunity to interference and stability. Besides, the sensor displayed better sensitivity and reliability (spiked recoveries of 98.0-105.2%, relative standard deviation of 3.45-5.69%) for detecting NOR in lake water, honey, and milk than high-performance liquid chromatography. This work provides a new strategy for developing poly(3,4-ethylenedioxythiophene)-based molecularly imprinted electrochemical sensors.