Development of a molecularly imprinted photoelectrochemical sensor for enhanced detection of ciprofloxacin in milk

In this work, a molecularly imprinted polymer (MIP)-based photoelectrochemical (PEC) sensor for the detection of ciprofloxacin (CIP) was constructed. Carbon-modified ZnO (ZnO/C) nanocomposite with adjustable zinc content was prepared by a carbonaceous method, facilitating visible light absorption and electron transition. The structure, morphology, and surface chemistry of ZnO/C were well characterized. The MIP membrane was formed by electropolymerizing, with ZnO/C nanocomposite, o-phenylenediamine (C₆H₄(NH₃)₂,o-PD), and CIP as highly efficient photoactive materials, functional monomer, and template, respectively. The PEC properties of different photoactive electrodes were measured and analyzed. The MIP-based PEC sensor showed excellent sensitivity and selectivity towards CIP, displaying a broad linear range from 0.01 nM to 1000 nM, a low detection limit of 8.41 pM, and satisfied recovery rates within 96.8%–103.2%. The sensor exhibited reliable reproducibility and stability, with a relative standard deviation (RSD) of 2.48% for the CIP in milk. The constructed MIP-based PEC sensor not only provides a powerful and reliable route for the detection of CIP, but also can be extended to detect other antibiotics in food and natural environment.