Hybrid ZnO nanostructures modified graphite electrode as an efficient urea sensor for environmental pollution monitoring

Herein, we propose a facile electrochemical sensing platform for urea detection using pencil graphite electrode modified nanocomposites of CuO/ZnO and Fe₂O₃/ZnO. The detection of urea is essential to monitor for identifying its pollution in the water, at the soil surface and in diagnosing urea cycle disorder related diseases. Therefore, an effective, accurate, cost-effective method of diagnosis is urgently needed. Nanostructured metal oxides have the potential ability to detect molecules even at trace level and to explore this, the present work is formulated with Cu and Fe based ZnO nanocomposites for enhancing the sensing performance towards electrochemical sensing of urea. The sensing responses were confirmed from the increase in oxidation current with respect to the concentration of urea. The results show that Fe₂O₃/ZnO coated graphite electrode has a higher response against urea compared to ZnO and CuO/ZnO. The cyclic voltammetry studies also validate urea sensing of Fe–ZnO in the linear range of 0.8 μg/mL to 4 μg/mL, with the detection limit of 2.5 μg/mL. This suggests that the cost-effective pencil graphite electrode modified Fe₂O₃/ZnO can be utilized as a promising analytical tool for urea sensing.