SIMPLE TECHNIQUE FOR MEASURING SURFACE-ENHANCED FOURIER-TRANSFORM RAMAN-SPECTRA OF ORGANIC-COMPOUNDS

A silver surface, suitable for Fourier transform surface-enhanced Rama n scattering (FT-SERS), has been prepared by subjecting a polished sil ver surface to an oxidation-reduction cycle in an electrochemical cell with KCl solution as the electrolyte. The surface produced by this me thod is shown, by scanning electron microscopy, to be very rough. The preparation of this surface is quite reproducible because the signific ant parameters of starting surface, electrolyte concentration, and pot ential can all be well controlled. After removal from the cell followe d by washing and drying, organic compounds can be placed on the surfac e as solutions in aqueous or organic solvents, or by exposure of the s urface to vapor. Typically, good FT-SERS spectra are obtained from 0.1 -2 mug of sample, after evaporation of the solvent. These experiments were not optimized for minimum detection limits. The technique is very simple, and spectra can be obtained with ease for a wide variety of c ompounds. Most compounds gave FT-SERS spectra which were similar to th eir solid Raman spectra; however compounds containing groups expected to interact strongly with the silver surface gave FT-SERS spectra very different from their normal Raman spectra.