Electrochemical Detection of Nitrites in Aqueous Samples Using Graphite Paste Electrode Modified Green Zinc Oxide Nanoparticles

ABSTRACT

The development of sensitive and sustainable nitrite detection sensors is critical given the possibility of health risks caused by nitrite pollution in waterways. In this study, the ZnO nanoparticles were successfully synthesized via a plant‐mediated synthesis route, offering an environmentally benign and sustainable approach. The X‐ray diffraction result confirmed the formation of a wurtzite hexagonal crystalline structure of ZnO. In addition, the Fourier transform infrared spectroscopy identified key functional groups from phytoconstituents such as polyphenols, flavonoids, alkaloids, and saponins involved in the synthesis. Moreover, the average particle size of the prepared zinc oxide nanoparticle was 80.47 nm. The electrochemical characterization showed the modification of phyto‐synthesized ZnO NPs enhancing the transport of electrons on the graphite paste electrode compared to the bare graphite electrode. The peak of electrooxidation of nitrite arose at 0.900 V versus Ag/AgCl, while no reduction peak was detected. In addition, the square root of scan rate and anodic current plot demonstrated that the mass transport of nitrite ions on the electrode surface was particularly controlled by diffusion. Furthermore, linear sweep voltammetry techniques revealed the ZnO NP/CPE has excellent catalytic activity toward nitrite oxidation, exhibiting high sensitivity, a linear range from 0.01 to 3 m