Development of core-satellite-shell structured MNP@Au@MIL-100(Fe) substrates for surface-enhanced Raman spectroscopy and their applications in trace level determination of malachite green in prawn

Malachite green (MG) abuse in aquaculture has caused food safety issues and surface-enhanced Raman scattering (SERS) can be utilized to monitor MG residues in aquatic products. However, the sensitivity and accuracy of SERS detection are limited by food matrix interference. Therefore, in this study, SERS active MNP@Au@MIL-100(Fe) substrates were developed by utilizing magnetic nanoparticle (MNP) as the core, which was evenly decorated with Au nanoparticles (AuNPs), and then coated with metal–organic frameworks (MOFs) shell of MIL-100(Fe), which acted as a filter to only allow molecules with appropriate sizes to approach the inner AuNPs, thus avoiding food matrix interference and improving the identification ability to analytes. Experiments in detecting MG residues in prawns was realized with the limit of detection (LOD) of 1.32 × 10 −10 M, showing great potential for its use as a reliable SERS substrate for monitoring food contaminants.