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

[Display omitted] •3D mesoporous nano-rods of peeled MMT/TiO2-ZnO hybrids were fabricated via sol-gel method.•The morphology and specific surface area of hybrids changed by changing the content of the MMT.•The sensor exhibited remarkable electrical conductivity and promoted the electron transfer rate.•The sensor achieved limit of detection of NO2– (0.12 nM).•The sensor detected NO2– in molasses without interference of the product ingredients. 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).