NiO-nanoflowers decorating a plastic electrode for the non-enzymatic amperometric detection of H2O2 in milk: Old issue, new challenge

In food supply chain, there are regulatory limitations on the use of chemicals for cleaning processing lines since the healthiness of the commodities must be guaranteed if accidently traces of these detergents and sanitizers pass to them. Hydrogen peroxide, is a commonly used sanitizer in the cleaning of the food processing lines having both bactericidal and bacteriostatic properties, however, it produces inflammatory effects on the human body. The availability of rapid systems to detect its accidental presence is therefore useful to speed up the control and apply corrective actions. In the present work, a drop casting and easily prepared plastic graphite/PVC electrode decorated with NiO nanostructures has been investigated as electrochemical sensor for the non-enzymatic amperometric determination of H2O2. The catalytic activity, dispersion, and stability of NiO nanostructures mixed with plastic nanocomposite electrode have been studied in detail. The preparation method, particularly the precipitating agents used in the synthesis of NiO nanostructures strongly influenced their morphology and porosity. Further, the electrochemical response of NiO-PE electrodes towards H2O2 resulted to be morphology-dependent. The non-enzymatic electrochemical sensor was optimized for the rapid and sensitive detection of H2O2 present in milk with no sample pre-treatments. NiO nanoflowers showed the best catalytic activity towards H2O2, a linear range that extends up to 4 mM and a LOD of 5 μM (3sd of the blank signal) were obtained.