Development of a sensitive electrochemical sensor for ractopamine detection using Nd2O3@Sm2O3-CNTs/GCE platform

Abstract

A sensitive electrochemical sensor was developed by sonication of multi-walled carbon nanotubes (CNTs) and nanoparticles of neodymium and samarium oxide (Nd₂O₃@Sm₂O₃). The electrochemical sensor (Nd₂O₃@Sm₂O₃-CNTs/GCE) possessing an electrochemically active surface area of 0.66 cm² and a charge transfer resistance (Rct) of 139 Ω could be utilized as a promising material compared to GCE, and CNTs/GCE. The Nd₂O₃@Sm₂O₃-CNTs/GCE system exhibited improved voltammetric behavior of ractopamine owing to the outstanding synergistic effect between Nd₂O₃@Sm₂O₃ and CNTs. The enhancement in electrochemical oxidation of ractopamine can be attributed to the synergistic effect between Nd₂O₃@Sm₂O₃ nanoparticles and CNTs, where the Nd₂O₃@Sm₂O₃ nanoparticles offer a high surface area and active sites, including oxygen vacancies that facilitate the oxidation of ractopamine, while the CNTs contribute excellent electrical conductivity, thereby accelerating electron transfer between the electrode surface and the analyte. A dynamic working range was obtained for the concentration of ractopamine between 2.0 × 10⁻⁸ and 5.0 × 10⁻⁵ M. Novel platform yielded 1.0 × 10⁻⁹ M as the limit of detection (LOD) for the determination of ractopamine. The present study yielding recoveries of 98.7–101.1 % and lower RSD% values confirms that Nd₂O₃@Sm₂O₃-CNTs/GCE enables precise and accurate measurements of ractopamine in biological fluids. In addition, voltammetric measurements provided a ΔG⁰ value of −22.7 kJ/mol for the interaction between ractopamine and DNA at 25 °C. This revealed that the binding process between DNA and ractopamine occurs spontaneously.