Fabrication of a colorimetric sensor using acetic acid-capped drug-mediated copper oxide nanoparticles for nitrite biosensing in processed food

Nitrite (NO 2 − ) and nitrate (NO 3 − ) are frequently used in cured meat products as preservatives, as they give a better taste and work well in color fixation. As a key possible carcinogen, excessive dietary consumption of NO 2 − in cured meat products would be bad for health. Herein, copper oxide nanoparticles (CuO NPs) were synthesized using the drug Augmentin as a reducing and capping agent. The desired synthesis of CuO NPs was confirmed by various characterization techniques, including UV–visible spectroscopy, Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, thermal gravimetric analysis, X-ray diffraction, and scanning electron microscopy. The new approach of drug-mediated acetic acid-capped CuO NPs was developed for simple colorimetric detection of nitrite ions in a mimic solution of processed food. The color of the detection system changes from brown to yellow with the increase in the concentration of NO 2 − and has been observed with the naked eye. The selectivity of the NO 2 − detection system by the UV–visible spectrum and the naked eye is compared to other ions, such as Br − , I − , Cl −1 , PO 4 −3 , CO 3 2− , and SO 4 2− . The platform was successfully employed for the determination of nitrite in real samples. Moreover, this probe can be used for the sensitive detection of NO 2 − with a linear range of 1 × 10 −8 to 2.40 × 10 −6 M, a detection limit of 2.69 × 10 −7 M, a limit of quantification 8.9 × 10 −7 M, and a regression coefficient ( R 2 ) of 0.997. Our results suggest that this sensor can be used for on-site analysis and quantification as well as in the fields of disease diagnosis, environmental monitoring, and food safety.