Surface-Enhanced Raman Analysis of some Polycyclic Aromatic Dyes used in the Cosmetics and Food Industries

The Surface-Enhanced Raman spectra of three important polycyclic aromatic dyes used in the food and cosmetic industries. Erythrosine, Eosine, and Phloxine, are recorded for the first time. The ability of the Surface-Enhanced Raman scattering techniques to detect these dyes at trace level is demonstrated. Such techniques minimize the fluorescence background in these highly fluorescing dyes, bringing out the Surface-Enhanced Raman Spectra features. The Normal Raman Spectra of erythrosine and phtalazine were also recorded and compared with their Surface-Enhanced Raman Spectra to illustrate the fluorescence suppression in Surface Enhanced Raman Spectra. The vibrational spectra features of the three dyes are discussed in terms of their molecular structure and the vibrations of the aromatic rings.