Surface-enhanced Raman spectrometry of a variety of drugs on colloidal silver is reported. Solvent effects on the Raman activity of adsorbates are discussed in terms of coadsorption and replacement kinetics at the silver surface. It is shown that the number of analytes amenable to SER spectrometry and the quality of the spectra can be improved by optimizing the solvent for the adsorbate under study. The influences of solvent on sensitivity, linear range of response, and shape of the calibration graph are discussed.
A. Rupérez and J. J. Laserna, "Solvent Effects on Surface-Enhanced Raman Activity of Adsorbates on Colloidal Silver," Appl. Spectrosc. 48, 219-223 (1994)