Fabrication of a ZnCo2O4 and laponite D-modified lab-made screen-printed electrode for chloramphenicol sensing

Chloramphenicol (CAP) is an antibiotic used in animal husbandry to treat bacterial infections, as well as a growth promoter. However, its residues in the food chain can pose a threat to human health. If accumulated in the body, it can lead to serious health problems such as bone marrow aplasia, circulatory system problems in newborn babies, and leukemia. Therefore, a new electrochemical sensor has been developed for the selective and sensitive determination of CAP in certain animal-derived samples such as honey, milk, and chicken meat. In this context, ZnCo2O4 nanoparticles were initially synthesized via a one-step solvothermal method. Subsequently, these nanoparticles were combined with laponite D (LapD) to form a composite, which was then applied to the surface of a laboratory-fabricated screen-printed electrode (LabSPE) to obtain the proposed sensor (ZnCo2O4-LapD/LabSPE). The sensor exhibited linearity within the CAP concentration ranges of 0.01–5 μM and 5–150 μM, with a detection limit of 7 × 10−3 μM. Furthermore, the effects of ZnCo2O4 and LapD concentrations, film thickness of ZnCo2O4-LapD, and pH of the electrolyte on the electrochemical response of CAP were studied in detail. The selectivity of ZnCo2O4-LapD/LabSPE toward CAP was assessed in the presence of drug active ingredients such as streptomycin, ciprofloxacin, tetracycline, clindamycin, and ampicillin.