Adapting and testing a portable Raman spectrometer for SERS analysis of amino acids and small peptides

Surface-Enhanced Raman Spectroscopy (SERS), a powerful spectrochemical technique enabling highly sensitive analysis of organic and biological materials, is investigated for applications in the analysis of archaeological materials including in situ screening. In this work, a compact mobile Raman spectrometer is employed for acquiring Surface-Enhanced Raman spectra from natural amino acids (l-Arg, l-Phe, l-Met) and a tripeptide (Glutathione), adsorbed on silver colloids. The detection limits of the portable Raman spectrometer, together with an optimization of sample preparation and experimental parameters, are reported. The collection and interpretation of SER spectra of amino acids and peptides is a starting point for the optimization of the instrumentation and its application in the study of more complex biological molecules in the context of detection and analysis of archaeological materials and residues.

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• A portable spectrometer is employed for SERS of amino acids at low concentrations.
• SERS of Arginine, Methionine, Phenylalanine from dried solutions (10-3 M) reported.
• SERS of dilute solutions of 2 amino acids and of a tripeptide (Glutathione) reported.