Core-Shell Regeneration Magnetic Molecularly Imprinted Polymers-Based SERS for Sibutramine Rapid Detection

Molecularly imprinted polymers (MIPs) have the ability of predesigned specific recognition that can be selected to construct reliable functional materials. Combining the MIPs with magnetic nanoparticles results in magnetic MIPs (MMIPs) which possess both facile manipulation and high selectivity. In this report, MMIP microspheres are fabricated by coating a layer of MIPs on Fe₃O₄@Ag for SERS-based sensing of molecular species. The obtained Fe₃O₄@Ag@MIPs are further applied for simple, rapid, ultrasensitive, and label-free SERS detection of sibutramine (SIB, illegal additive), with a low LOD of 1.0 × 10^-9 M. Moreover, the MMIP microspheres exhibit ultrahigh adsorption efficiency, selectivity, reusability, and good structural stability, which demonstrates the potential application for SERS. Particularly, the proposed approach of MMIPs-SERS can be successfully applied to quick screening of SIB in slimming supplements such as capsules, tea powder, and tablets, and the content for those is 6.18, 13.61, and 3.09 mg g^-1, respectively. These properties make MMIP microspheres a promising SERS substrate to detect illegal additives in health-related products and chemical pollutants in the environment.