The Signal Amplification in Electrochemical Detection of Chloramphenicol Using Sulfonated Polyaniline-chitosan Composite as Redox Capacitor

In this work, a novel redox capacitor was designed for signal amplification in electrochemical detection. It was fabricated by co-electrodeposition of a conducting polymer, sulfonated polyaniline (SPAN) and chitosan on a glass carbon electrode, and its function was evaluated for being a localized source to transfer electron between FcCOOH (Fc) and Ru(NH 3 ) 6 Cl 3 in solution via redox cycling. Furthermore, the electrochemical detection of chloramphenicol, a broad-spectrum antibiotic was performed using the redox capacitor in the presence of Fc. A significant amplification in cathodic current response of chloramphenicol was obtained through a continuous redox-cycling reaction. The performance of the amplifying signal responded linearly to chloramphenicol in a concentration range of 0.05 to 50.0 μmol L −1 with a low detection limit of 0.01 μmol L −1 . The proposed approach exhibited good reproducibility and stability, and could be used for detection of chloramphenicol in eye drops by standard addition method with the recoveries from 96.5 % to 103.0 %.