CHEMO-OPTICAL SENSING BY SERS AT ORGANICALLY MODIFIED SURFACES

The preparation and properties of sulphurorganically modified SERS (surface-enhanced Raman scattering) substrates are described. These substrates are based on partially transparent rough metal films, which may be used at SERS fibre sensors. The sulphurorganic surface compounds are stable within various solvents and the modified substrates might thus be useful for sensing in various media. Substrates coated with p-mercaptoaniline exhibit pH-dependent SERS spectra. Adsorption of alkylthiols on silver gives hydrophobic substrates with an alkyl chain conformation depending on the surface density of the molecules. Reactions between immobilized thioethanol and isocyanate leading to surface urethane as well as between immobilized mercaptoacetic acid and amines can be used for coupling adsorption centres to SERS substrates.