Fourier transform surface‐enhanced Raman scattering for the detection and identification of polyaromatic hydrocarbons

Fourier transform surface‐enhanced Raman (FT‐SER) spectra of 18 polyaromatic hydrocarbons (PAHs) were measured on a silver surface which had been previously roughened by an oxidation‐reduction procedure in an electrochemical cell. The sample was placed on the clean surface as a solution in an organic solvent and the solvent allowed to evaporate. All the samples had significantly different SER spectra. Detection limits were around 10−9 mol for most compounds but were higher for a few compounds, particularly azulene. For most samples the SER spectrum obtained was similar to the FT‐Raman spectrum of the solid sample. For one sample, azulene, a different spectrum was obtained by the SER technique, indicating a different, or additional, SER mechanism for this sample. A brief investigation of the quantitative aspects of the technique showed that, over the range studied, the intensity of the SER spectrum was related linearly to the amount of compound present on the surface.