Reaction Mass Spectrometry Of The Intermolecular Interaction Cold-spray Mass Spectrometry As Well As Several Organic Molecules

Coldspray Ionization (CSI) was a novel mass spectrometric technique developed from ESI-MS. In the CSI-MS, the spray and the desolvation chamber are made cool during solution is delivered into the ion source, thus ionization is promoted based on increased polarizability of the compounds caused by the higher dielectric constant at low temperature. It can preserve the integrity of clusters aggregated by weak interaction well and reflect the 'actual' molecular behavior in solution. It has been applied in characterization of solution structures of many labile organometallic complexes and primary biomolecules including amino acid and double-stranded DNA, etc.In this dissertation, the application of CSI-MS is expanded in characterization of cluster structure of natural products and drug molecules. On the basis of previous study of intermolecular interaction of nucleoside mixture systems, the molecular clusters of butanedioic acid bisglucopyranosyloxybenzyl ester, oligosaccharide and oxytetracycline were investigated. The results indicated that CSI-MS can afford the facile and precise characterization of cluster structure formed by organic molecules with considerable molecular weight. Compared with ESI-MS, CSI-MS technique is proved to be the more suitable tool to detect intermolecular interactions in solution. In the study of noncovalent interactions between nucleosides and some drugs or natural products, very evident differences in the intensity of complex ions were observed. Then the selective differences in cluster formation were detected. The magnitude of weak intermolecular interactions calculated from semi empirical method (AMI) and Bader's theory of atoms in molecules (AIM) were in agreement with the observed CSI-MS results. The information of CSI-MS is believed to be valuable and reliable in the discussion of the noncovalent interactions between drug molecules and drug-biomacromolecule.