Preparation of an electrochemical sensor for determination of chloramphenicol using ZnCo2O4-laponite D nanocomposite

The aim of this study was the electrochemical determination of chloramphenicol (CAP), an antibiotic used in animal treatment and to which humans are also exposed due to excessive or random use. Firstly, a screen-printed electrode (LabSPE) was prepared in the laboratory by applying carbon and silver inks on a polycarbonate surface using screen printing technology. Then, the surface of the working electrode surface was modified with ZnCo2O4-LapD nanocomposite consisting of ZnCo2O4 and Laponite D (LapD) substances to be used in the electrochemical analysis of CAP. The structural and morphological properties of the prepared sensor materials were comprehensively characterized by FT-IR, XRD, XPS, TEM, and FESEM-EDX analyses. Additionally, the effects of the concentrations of ZnCo2O4 and Laponite D, the thickness of the composite film, and the pH of the buffer solution on the electrochemical signal of the prepared sensor were thoroughly investigated. The modified screen-printed electrode showed linear responses in the concentration ranges of 0.01–5 µM and 5–150 µM, with a detection limit determined as low as 7×10-3 µM. Finally, the developed sensor was successfully applied for the detection of CAP in animal-derived samples such as milk, honey, and chicken.