Electrochemical Detection of Nitrite Based on Co<sub>3</sub>O<sub>4</sub>-Au Nanocomposites for Food Quality Control
Venkatesh S. Manikandan, Sharmila Durairaj, Emmanuel Boateng, Boopathi Sidhureddy, Aicheng Chen
Abstract
Nitrite (NO2−) is one of the most intensively studied species in foods owing to its detrimental effects on the human body. Here we report on a high-performance electrochemical sensor based on cobalt oxide nanosheets and gold nanoparticles (Co3O4/Au) for the detection of NO2−. The structural morphology and chemical composition of the nanomaterial were examined using a scanning electron microscope and energy dispersive X-ray spectroscopy. The Au/Co3O4/GCE (glassy carbon electrode) was capable of electrooxidizing NO2− at a low onset potential with a higher anodic peak current over other modified electrodes (bare GCE, Co3O4/GCE, and Au/GCE). The analytical performance of the electrochemical sensor was tested using square wave voltammetry. The sensor exhibited good linearity in the selected concentration range from 1.0 to 4000.0 μM with an R2 value of 0.999 and the limit of detection (LOD) of 0.11 μM. The Au/Co3O4/GCE demonstrated high selectivity and good stability. Moreover, the Au/Co3O4/GCE showed a good anti-interference capacity in the presence of other potential co-existing ions. The performance of the developed sensor was scrutinized further with commercial bottled water and a beef sample with good recovery rates, thereby confirming its plausible applications in food and beverage safety and quality control.