Surface Enhanced Raman and 2D-Fluorescence spectroscopy for the investigation of amino acids and egg proteins

Fluorescence excitation-emission spectroscopy and Surface-Enhanced Raman Spectroscopy (SERS) are applied in the analysis of model proteinaceous compounds with the aim to develop versatile methodologies so as to aid analytical investigations of organic and bio-organic archaeological residue materials. A compact mobile Raman spectrometer was employed and SER spectra were collected from thin film samples of natural amino acids (L-Trp, L-Tyr, L-Cys) and egg white, properly mixed with silver colloidal nanoparticles. In parallel the fluorescence behavior of egg white, egg yolk and milk films was investigated on a laboratory spectrofluorimeter. Comparison of 2D-fluorescence excitation-emission maps collected from fresh and aged films, revealed the formation of new fluorophores, indicative of chemical alteration and degradation process of the proteins taking place during aging. (C) 2015 Elsevier B.V. All rights reserved.