Synthesis of Magnetic Polyphosphazene-Ag as Surface Enhanced Raman Spectroscopy Substrate for the Detection of Melamine

Abstract Magnetic polyphosphazene particles (MPZS) coated by Ag nano-particles (MPZS-Ag) have been developed as surface enhanced Raman spectroscopy (SERS) substrate for sensitive detection of melamine in aqueous solutions and milk samples. The 5, 5'-Dithiobis-(2-nitrobenzoic acid) (DTNB) was used as model analyte to test the SERS activity of the MPZS-Ag particles. The prepared SERS substrate possesses both magnetic responsiveness and excellent SERS properties. SERS detection of different concentrations of melamine aqueous solutions and spiked milk samples were performed by the MPZS-Ag. The limit of detection (LOD) of the melamine in aqueous solution was 10 -7 mol/L and 0.6 mg/L in spiked milk sample by the MPZS-Ag. The detection results are much lower than the safety values of Food and Drug Administration and Codex Alimentarius Commission. These results indicate that the MPZS-Ag possesses high SERS sensitivity and has promising application prospect for SERS analysis in food safety fields.