SERS based determination of vanillin and its methyl and ethyl derivatives using flower-like silver nanoparticles on a silicon wafer

A surface enhanced Raman scattering (SERS) method is described for the determination of vanillin, methyl vanillinand ethyl vanillinat trace levels. Flower-like silver nanoparticles on a silicon wafer are used as the SERS substrate, and the analytes can be specifically and non-destructively recognized by their specific Raman bands. The molecules can be recognized rapidly by identifying the characteristic bands. The SERS spectra of vanillin(C8H8O3) were used as mid-contrast, and specific bands of methyl vanillinand ethyl vanillin(C9H10O3) were acquired at 775 cm−1, 1350 cm−1 and 1282 cm−1, 1382 cm−1, respectively. In addition, by using an improved principal component analysis(PCA) algorithm, the organic molecule can be quantitatively determined. Dissolved in water, vanillin, methyl vanillinand ethyl vanillinstill can be detected at a concentration of 10−8 M, at which their characteristic Raman peaks are still visible. The method was successfully applied to the determination of vanillinin milk powder products.