Boosted electron transfer kinetics in a rGO–Fe3O4/TiO2 nanocomposite toward trace-level detection of chloramphenicol

Abstract

The quick and efficient analysis of antibiotic residues in food and environmental samples is a major challenge. In the current work, a ternary rGO–Fe₃O₄/TiO₂ nanocomposite was prepared and used as an effective electrocatalytic sensing platform to electrochemically detect chloramphenicol (CAP). The synergistic co-assembly of the conductive reduced graphene oxide (rGO), redox-active Fe₃O₄ NPs, and semiconducting TiO₂ was able to create a heterostructured interface to allow fast transfer of electrons and increase surface-active sites. The success of the hybrid nanocomposite with the uniform dispersion of metal oxides all over the rGO sheets was confirmed with the help of structural and morphological characterization. Electrochemical studies revealed a large reduction in current towards CAP as opposed to that of the single components, and this is a strong sign of electrocatalytic activity. The modified electrode was found to have high sensitivity, a large linear detection range, a low detection limit, excellent repeatability, and reasonable selectivity in the presence of possible interfering species. In particular, quantitative parameters like the limit of detection (LOD = 0.88 µM), limit of quantification (LOQ = 2.95 µM), sensitivity (4.01 µA µM⁻¹ cm⁻²), linear range of detection (2–100 µM), relative standard deviation (RSD = 1.79%) in reproducibility. These extensions give a more accurate picture of the sensor in terms of its analytical capabilities and usability. The findings provide a more concise emphasis on the importance, robustness, and sensitivity of the developed rGO–Fe₃O₄/TiO₂-based electrochemical sensor to detect chloramphenicol. Moreover, the sensor was found to be stable in real sample analysis, which implies its potential use in environmental and food safety monitoring. The synergistic interactions between charge-transfer and the higher adsorption capacity of the rGO–Fe₃O₄/TiO₂ ternary system are responsible for the enhanced sensing performance.