Surface-enhanced Raman scattering sensor based on MWCNTs@ZnO/Ag to detect the enrofloxacin in pork

The threats of antibiotic residues to human health and the environment have become more and more severe due to the overuse of antibiotics in agriculture. Here, multi-walled carbon nanotubes (MWCNTs) were used to prepare MWCNTs@ZnO/Ag substrate by a simple two-step electrochemical deposition process to detect the enrofloxacin (ENR) residues in pork. The coral-like MWCNTs with a large surface area could promote ENR adsorption and provide more sites for growing the ZnO/Ag nanostructures. Moreover, ZnO/Ag nanostructures could not only facilitate the electron transfer to increase Raman intensity but also improve the stability of MWCNTs@ZnO/Ag substrate. Thus, the MWCNTs@ZnO/Ag substrate could easily recognize ENR molecules at a low concentration of 5 × 10⁻¹⁰ M due to the stronger charge transfer effect between the substrates and analytes. In addition, the limit of detection of ENR residues in pork samples by using MWCNTs@ZnO/Ag substrate was up to 5.87 nM. The SERS sensor of the MWCNTs@ZnO/Ag substrate has a high sensitivity and long-term stability for the detection of antibiotic residues in food, which could be applied in fields of food safety.