ABSTRACT
Nuclear magnetic resonance (NMR) is a spectroscopic technique particularly suited to structural investigation of single molecules, able to provide geometrical information adopted to establish the three-dimensional structure of the molecule under investigation. Different instruments solutions allowed to open wide the use of NMR to different research field: high resolution (HR), low resolution or low field and magnetic resonance imaging that can give different and complementary information. HR allows qualitative and quantitative analysis of samples in both liquid and solid or semisolid states as well as structural information down to microstructural level; in latter case, the magic angle spinning condition have to be used. Time-domain NMR gives information about the relaxation time, strictly correlated with intra and intermolecular motions, diffusion processes, and structural properties of liquids in porous systems or amorphous phase and systems consisting of different phases. Site-specific natural isotope fractionation NMR technique constitutes the most specific and sophisticated method used for food authenticity determination by investigating the isotopes ratio.
