Unraveling the Roles of Morphology and Steric Hindrance on Electrochemical Analytical Performance of α -Fe 2 O 3 Nanostructures-Based Nanosensors towards Chloramphenicol Antibiotic in Shrimp Samples

In this work, we investigated the effect of morphology on the analytical performance of α -Fe 2 O 3 nanostructures-based electrochemical sensors toward chloramphenicol (CAP) antibiotic using three designed morphologies including α -Fe 2 O 3 nano-tube ( α -Fe 2 O 3 -T), α -Fe 2 O 3 nano-rice ( α -Fe 2 O 3 -R), and α -Fe 2 O 3 nano-plate ( α -Fe 2 O 3 -P). Among these morphologies, α -Fe 2 O 3 -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 -Fe 2 O 3 -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 -Fe 2 O 3 -R was highest in investigated morphologies owing to a high density of exposed Fe 3+ as well as less SD effect towards CAP molecules. Under optimized conditions, α -Fe 2 O 3 -R-based CAP electrochemical sensor reached an electrochemical sensitivity of 0.92 μ A μ M −1 cm −2 with a LOD of 0.11 μ M in the detection range from 2.5–50 μ M. In addition, all these α-Fe 2 O 3 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 -Fe 2 O 3 nanostructures towards antibiotics, which is helpful to the design of novel α-Fe 2 O 3 -based electrochemical nanosensors.