Adsorption of ortho- and para-phthalic acids on oxidised aluminium foil was investigated by Raman and surface-enhanced Raman spectroscopy (SERS). Without any treatment of the foil only a modified method of SERS provided spectroscopic evidence of the adsorption. However, by dissolving the metal aluminium from the Al2O3-Al-Al2O3structure of the foil, the adsorption could be investigated by Raman spectroscopy without surface-enhanced conditions. The vibrational bands of the adsorbed species, obtained by both types of Raman spectroscopy, are compared to the solid-state spectra of the pure acids and their dipotassium salts. The hand shifts suggest that the adsorbed species are essentially in the carboxylate form; however, the Raman and the SER spectra of the same species are not identical indicating a separate chemical reaction occurring at the surface upon depositing the sol.
Klug, O., Parlagh, G., & Forsling, W. (1997). Raman spectroscopy of aromatic acids adsorbed on oxidised aluminium foil. In Journal of Molecular Structure (Vol. 410–411, pp. 183–188). https://doi.org/10.1016/S0022-2860(96)09692-5