The Department of Physics, Stockholm University
Tuesday 16 October
10:00 - 14:00
This thesis comprises the research related to interactions of enantiopure amino acids with chiral and achiral molecules in gas phase. The investigation of the mechanism responsible for chiral discrimination is of the special interest in this work. An electrospray ion source platform (Stockholm University), quadrupole time-of-flight mass spectrometer (University of Oslo) and Fourier-transform ion cyclotron resonance mass spectrometer in combination with OPO laser (Centre Laser Infrarouge d’Orsay (CLIO), France) have been used in our studies. Results of experiments on collisions of enantiopure amino acids, namely phenylalanine (Phe), tryptophan (Trp), and methionine (Met) with chiral and achiral targets in high and low energy regimes are presented. The fragmentation process is discussed in detail and compared with generally accepted models of amino acid fragmentation. Formation of proton bound diastereomeric adducts of amino acid and chiral alcohols (2-butanol and 1-phenylethanol) in single collisions is reported. The emphasis was given to reveal stereochemical effects in above mentioned reactions. The structure and vibrational properties of diastereomeric dimers of tryptophan studied using infrared multiphoton dissociation (IRMPD) spectrometry are presented. Structures and energies of most stable conformers obtained with quantum chemical calculations are described and compared to the experimental data. The stereo-dependent features are underlined and the chiral discrimination using IRMPD is addressed.