This project is aimed to study charged supramolecular adducts and naked ions in the gas phase through the application of advanced hyphenated techniques based on mass spectrometric and spectroscopic devices. Object of the study is the structural characterization of the investigated species in order to ascertain: 1) the chemical identity of both the m/z selected ions and their relevant fragments obtained by MSn (typically n=2, 3) dissociation; 2) the nature and the strength of the non-covalent interactions responsible of the actual conformation of free charged molecules (intramolecular interactions) and supramolecular organization within ionic clusters (intracomplex interactions), including chiral systems. To this end a crucial role is played by in-silico simulations of the experimental gas-phase results obtained through theoretical calculations. Gas Phase investigation of the structure of single species and supramolecules offer an exclusive, "intimate" view of the non-covalent interactions in act, without any interference by environmental factors (e.g. solvation, pH, ionic strength, counterion), whose role in condensed phase can affect the intrinsic behavior of the system. Because of the ubiquitous nature of the solvent, the effect of environmental factors is difficult to evaluate in condensed phase, but it clearly emerge from the comparison of gas-phase experiments on the same system.
The present project is aimed to investigate:
1) representative DNA adducts relevant as biomarkers of exposure to genotoxic substances and for cancer risk assessment, in order to test the potentiality of the IRMPD spectroscopy in discriminating the nature of the modifications and the base sites in which they took place;
2) the time dependent structural characteristics of the proton bound complexes [C¿H¿G]+ formed between the home made macrocycle rccc-2,8,14,20-tetra-n-decyl-4,10,16,22-tetra-O-methylresorcinarene (C) and D-(+)-Galactosamine (G).