Fabrication of a non-enzymatic electrochemical sensor based on magnesium oxide nanosheets for selective and sensitive detection of hydrogen peroxide in food samples

A novel enzyme-free sensor, constructed on a glassy carbon electrode (GCE) and featuring 2-dimensional (2-D) nanoporous magnesium oxide nanosheets (MgO-NSs), has been fabricated to enable the highly sensitive and selective detection of hydrogen peroxide (H2O2). MgO-NSs were successfully synthesized through a single-step, non-hazardous, and cost-effective sugar-blowing technique. The microstructure, porosity, thermal stability, and morphology of MgO-NSs were analyzed under XRD, FT-IR, FESEM, HR-TEM, TGA, and BET surface area. The electrochemical properties of MgO-NSs modified glassy carbon electrode (GCE) (MgO-NSs/GCE) were probed toward H2O2 sensing using CV, DPV, EIS, and amperometry techniques at varying concentrations, pH of the solution, and different scan rates. The fabricated electrode displayed remarkable selectivity, high sensitivity, and a linear response toward H2O2 in a wide concentration range of 20 mu M-1000 mu M at neutral pH with 0.224 mu M limit of detection (LOD) and 0.753 mu M limit of quantification (LOQ). The proposed electrochemical sensor based on MgO-NSs/GCE demonstrates multiple advantages like exceptionally high sensitivity, high selectivity, great stability, reproducibility, and excellent response toward the detection of hydrogen peroxide in milk and mixed-fruit juice samples as compared to the reports available in the literature.