Unraveling the Roles of Morphology and Steric Hindrance on Electrochemical Analytical Performance of α-Fe₂O₃Nanostructures-Based Nanosensors towards Chloramphenicol Antibiotic in Shrimp Samples

In this work, we investigated the effect of morphology on the analytical performance of α-Fe2O3 nanostructures-based electrochemical sensors toward chloramphenicol (CAP) antibiotic using three designed morphologies including α-Fe2O3 nano-Tube (α-Fe2O3-T), α-Fe2O3 nano-rice (α-Fe2O3-R), and α-Fe2O3 nano-plate (α-Fe2O3-P). Among these morphologies, α-Fe2O3-T displayed an outstanding electrochemical activity owing to the unique hollow structure and large specific surface area. However, due to the small pores size, α-Fe2O3-T showed the high steric hindrance (SD) effect towards an antibiotic with complex molecular structure, as CAP, leading to a significant decrease of their CAP electrochemical sensing performance. The CAP analytical performance of α-Fe2O3-R was highest in investigated morphologies owing to a high density of exposed Fe3+ as well as less SD effect towards CAP molecules. Under optimized conditions, α-Fe2O3-R-based CAP electrochemical sensor reached an electrochemical sensitivity of 0.92 uA uM-1 cm-2 with a LOD of 0.11 uM in the detection range from 2.5-50 uM. In addition, all these α-Fe2O3 nanostructures-based electrochemical sensors had excellent stability and high anti-interference ability for CAP analysis in a complex food matrix, as shrimp sample. This study provides valuable insights into the morphology-dependent sensing properties of α-Fe2O3 nanostructures towards antibiotics, which is helpful to the design of novel α-Fe2O3-based electrochemical nanosensors.