Recyclable Magnetic MIP-Based SERS Sensors for Selective, Sensitive, and Reliable Detection of Paclobutrazol Residues in Complex Environments

In this work, a molecularly imprinted polymer (MIP)-based SERS sensor for selective, sensitive, quantitative, and recyclable detection of paclobutrazol residues in complex environments has been proposed. In this strategy, Fe3O4@SiO2–Au@Ag (FSAA) nanocomposites with tunable Au@Ag interparticle gaps are constructed. Then, by tuning the Au@Ag nanogaps and investigating the SERS enhancement mechanism of FSAA, we achieve the optimal SERS substrate, FSAA-40. After combining with MIPs, we can selectively detect paclobutrazol in soil with a detection limit of 0.075 μg/g. When the paclobutrazol concentration ranges from 0.075 to 12.75 μg/g, the SERS intensity shows a linear correlation, which opens the possibility for quantitative detection. Our magnetic MIP-based SERS sensor can be easily separated, efficiently recycled, and expanded to more universal environments, which demonstrates a promising future in food and environmental safety.