Preparation Of Surface Enhanced Raman Spectroscopy Substrates And Their Application In Detection Of Common Colorants

Food safety is becoming the focus of attention currently. Therefore, a high sensitivity, good accuracy and fast detection method is in need. Surface enhanced Raman spectroscopy(SERS) has been gradually applied in environmental science, food detection and biomedical sciences with the advantages of high sensitivity, low concentration detection limit, fast and convenient detection. In this paper, we aimed to investigate the feasibility of SERS for robust detection of four common colorants sunset yellow, tartrazine, amaranth, brilliant blue and prohibited colorants Sudan Red(?-?). This paper mainly includes the following two aspects:Firstly, Ag nanoparticles was prepared by using polyethylene imine(PEI) as reducing agent and protective agent through one-step reduction precedure, and then the silver nanoparticles(Ag NPs) was used as SERS substrate to detect four common colorants, including: sunset yellow, tartrazine, amaranth and brilliant blue. The pH, ratio of reactants, temperature of PEI-Ag nanoparticles were optimized and the results showed that under the optimal conditions: p H4, reaction temperature 140?,nPEI : nAg = 0.2:1, the SERS detection of these four colorants has achieved good results. Meanwhile the mixture of four colorants was detected by PEI-Ag substrate simultaneously, which has proved the potential of this novel SERS substrate in the food industry detection.Secondly, PVA-Ag-G-S three-dimensional(3D) hydrogel substrate has been prepared by adding surfactant assisted dispered graphene dispersion into PVA-Ag sol, crystal violet(C V) was used as probe to investigate the effect of graphene and surfactant in the PVA-Ag 3D hydrogel. Then the PVA-Ag-G-S 3D hydrogel has been applied to detect four common colorants sunset yellow, tartrazine, amaranth, brilliant blue and prohibited colorants Sudan Red( ?- ?), respectively. The SERS spectra of these colorants were matched with their Raman spectra very well. The PVA-Ag-G-CTAB 3D hydrogel has been comfired to be effective and was used to detect the mixture of four colorants and the mixture of Sudan Red, respectively. Also, this 3D hydrogel was used to detect the practical samples samples and good results were achieved.