Frontiers of UV Resonant Raman spectroscopy by using synchrotron radiation: the case of aqueous solvation of model peptides

UV Resonance Raman (UVRR) scattering offers several advantages with respect to spontaneous Raman one, such as the significant increment of the detection limit and the selectivity needed to incisively monitor specific chromospheres within the sample. Here we present a synchrotron-based Resonance Raman instrument that exploits the wide and continuously tunable UV emission provided by the synchrotron source. As an example, we discuss the solvation dynamics of two model peptides, N-acetyl-leucine-methylamide (NALMA) and N-acetyl-glycine-methylamide (NAGMA), by putting in evidence on the advantages of the use of SR-based UVRR. The experimental results evidence that the fine tuning of the excitation wavelength allows to choose the best working conditions that ensure to reliably detect the spectral changes of the amide signals, as function of concentration and temperature of peptide. The analysis of the spectra provides new insights on the hydrogen-bond interactions at the peptides backbone.