Advanced sensing platform for nanomolar detection of food preservative nitrite in sugar byproducts based on 3D mesoporous nanorods of montmorillonite/TiO2–ZnO hybrids

Abstract

Nitrite (NO2−) pollution pose hazards to human health. NO2− oxidizes haemoglobin to methaemoglobin, thereby minimizing the oxygen-conveying capacity. Herein, we synthesized three-dimensional (3D) mesoporous nanorods (MNRs) of peeled montmorillonite (MMT)/TiO2–ZnO hybrid modulated sensors as a robustly sensitive electrochemical sensor for detecting NO2− using the square-wave adsorptive anodic–stripping voltammetry. The 3D mesoporous nanorods of coupled TiO2–ZnO composite [TZ] and series of MMT/TiO2–ZnO hybrids were synthesized using various contents of MMT [MTZ1-4] MNRs via a sol–gel method. Varying the weight percentage of MMT exhibited remarkable effects including changing of the geometrical structure, superficial area, and degree of porosity. Notably, [MTZ2] with 1.0% of MMT exhibited the most structured MNR morphology and best superficial area (77.6 m2/g) with minimal resistivity. Cyclic voltammetry revealed that the developed modulated sensor with 1.0% [MTZ2] MGPS preserved a remarkable electrocatalytic activity as evaluated from the cyclic voltammetry (CV) mensuration. Under optimal operating conditions, the proposed sensor achieved a linearity range of 0.04–10 nM and a limit of detection of 0.12 nM for NO2− with sensitivity (0.78 μA.nM−1). It also achieved good accuracy, precision, and high selectivity for detecting NO2− in food preservatives such as sugar byproducts (molasses products).