Sensitive electrochemical sensor for the detection of ciprofloxacin by reduced graphene oxide-loaded spherical silver nanoparticles

In this study, an electrochemical sensor based on AgNPs-rGO composites was developed for the rapid detection of the antibiotic ciprofloxacin (CIP). The electrochemical performance of the AgNPs-rGO composite was evaluated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and differential pulse voltammetry (DPV) systems. The results showed that the AgNPs-rGO composites exhibited the lowest charge transfer resistance and the best electrocatalytic performance compared with Ag or rGO electrodes alone, indicating that the synergistic effect between Ag and rGO significantly enhanced the sensitivity and responsiveness of the electrodes. The modification amount of AgNPs and the coating amount of the material were further optimized, and it was found that the sensor exhibited the best performance when the content of AgNPs was 0.01 mmol and the coating amount was 4 µL. The sensor achieved a detection limit of 6.25 nM (S/N = 3) for CIP, and showed high recoveries (93.20 %–97.25 %) and good reproducibility (RSD < 2.33 %) in real samples of tap water and river water. In addition, tests showed that the AgNPs-rGO composite had a good electrochemical active area, further demonstrating its potential in electrochemical sensors. This study demonstrates that the developed sensor has good sensitivity and stability in CIP detection, which opens up possibilities for its application in environmental and public health fields.