Magnetic-responsive sensors based on polydopamine macromolecules for highly sensitive detection of trace food colorant residues.

As a kind of unique biomimetic macromolecule, polydopamine (PDA) have prominent in-situ reduction ability and interfacial adhesion. In this work, combined with in-situ reduction ability of PDA and excellent magnetic response performance of nickel foam (NF), a strategy was designed to fabricate a series of NF@PDA@AgNPs as magnetic-responsive surface enhancement Raman scattering (SERS) substrates for highly sensitive Rhodamine B (RhB) detection in chili powder. With crystal violet (CV) as probe molecule, the detection limit of SERS substrate could achieve 10 M, and the enhancement factor was as high as to 2.22 × 10. In addition, the NF@PDA@AgNPs SERS substrates showed excellent magnetic separation efficiency, good SERS uniformity and storage stability. More importantly, these substrates could achieve highly efficient collection and sensitive detection of RhB residues in chili powder by magnetic adsorption method, and the detection of limit was as low as to be 10 g/g. These NF@PDA@AgNPs substrates would be a great prospect for rapid and efficient pernicious contaminant detection in the chemical and biological fields.