A facile and selective resonance Rayleigh scattering method for trace Sudan Red III with magnetic nanosurface molecularly imprinted polymethacrylic acid probe

In this article, using magnetic iron tetraoxide nanoparticles (Fe3O4) as the nanosubstrate, Sudan red III (SRIII) as the template molecule, methacrylic acid (MAA) as the functional monomer, ethylene glycol di-methacrylate (EGDMA) as the cross-linking agent, and 2,2 '-azobisisobutyronitrile (AIBN) as the initiator, a new bifunctional magnetic surface molecularly imprinted polymer nanoprobe (Fe3O4@MIP) with both recognition function and enrichment function was prepared by the microwave irradiation procedure. The probe was characterized by molecular spectra, electron microscopy, energy spectroscopy and specific surface areas. The probe exhibits a resonance Rayleigh scattering (RRS) peak at 370 nm, the RRS energy transfer (RRS-ET) effect was enhanced with the increase of SRIII concentration, and the RRS intensity at 370 nm was decreased linearly. Accordingly, a new RRS-ET method was developed for the sensitive and selective determination of 0.05-1 nmol/L SRIII, with a detection limit of 0.017 nmol/L. The recoveries were in the range of 93.1 similar to 106 % with the relative standard deviations (RSDs) in the range of 3.14 similar to 8.37 % for the real samples. The enrichment ratio of Fe3O4@MIP probefor SRIII was 100 by means of the magnetic separation.