Co-precipitation synthesis of cobalt doped ZnO nanoparticles: Characterization and their applications for biosensing and antibacterial studies

A new modified sensor based on carbon paste electrode (CPE) was developed using cobalt doped ZnO (Co-ZnO) nanoparticles (NPs). In this work, we demonstrated the analytical behavior and applications of CPE modified with Co-ZnO/MCPE for the simultaneous determination of uric acid (UA) and adrenaline (AD) with highly selective and sensitive using voltammetric techniques. The synthesized Co-ZnO NPs were characterized by utilizing XRD, FTIR, FESEM with EDX, TEM, UV-Vis and photoluminescence spectroscopy. XRD suggests that the average size of these NPs was between 21 and 35 nm with a hexagonal wurtzite structure. Tauc plot exhibited that the optical energy bandgap of ZnO NPs gradually decreases with Co doping. Compared with undoped ZnO, Co-ZnO modified carbon paste electrode (Co-ZnO/MCPE) exhibits excellent electrochemical performance towards the oxidation of UA. Influencing factors, including scan rate, concentration, and pH values were optimized. Under the optimal condition, the Co-ZnO/MCPE responded to UA linearly with a detection limit of 3.37 mu M and the fabricated sensor exposes diffusion-controlled electrode process. The developed Co-ZnO/MCPC has capable of determination of both UA and AD simultaneously with two different oxidation peaks. The sensitivity, long-term stability and reproducibility of the developed sensor were estimated. The bacterial efficiency of undoped and CoZnO NPs was inspected against gram-negative (Escherichia coli) and gram-positive (Enterococcus faecalis) bacteria.

Automated summary

The article presents a new modified sensor based on a carbon paste electrode using cobalt doped zinc oxide nanoparticles for the simultaneous determination of uric acid and adrenaline with high selectivity and sensitivity. Characterization and optimization were performed to fabricate a sensor with excellent performance towards the oxidation of uric acid. The synthesized sensor is capable of determining both analytes simultaneously with diffusion-controlled electrode processes.