NSF Young Investigator: Gas-Phase Host-Guest Chemistry and Detection of Antibiotics

点击翻译按钮获取中文摘要

Two areas of research will be pursued: (1) Host-guest chemistry in the gas-phase and (2) Laser desorption/selective ion-molecule reactions of antibiotics. In the first topic, a variety of aspects of solvent-free host-guest chemistry of model systems will be investigated by application of mass spectrometric techniques. The model systems include an array of size-selective hosts (i.e., crown ethers and related macrocycles and acyclic analogs) and guests (i.e., various metal ions, halide ions, or ammonium ions). The macrocyclic host-guest complexes will be formed via bimolecular reactions in the gas-phase, then their structures and binding energies will be evaluated by collision-induced dissociation techniques. In the second topic, laser desorption/selective ion-molecule reaction methodology in a quadrapole ion trap will be developed for antibiotics, especially those whose activities are controlled by metal ion binding. Through the use of selective bimolecular reactions that chemically modify the biological molecules of interest, structural details will be obtained based on how the modified molecules dissociate and if the molecules undergo structurally-specific reactions. %%% This grant from the Organic Dynamics Program supports the research of Professor Jennifer S. Brodbelt at the University of Texas, Austin. Complexation between a host molecule and a guest molecule or ion, which is important to understanding many biological processes, will be studied in the gas-phase. This will allow for an evaluation of the binding forces between the host and guest without solvent contributions. By this means, the primary forces in this molecular recognition will be deduced. In another project, techniques will be developed to characterized antibiotic molecules, especially those whose activities are determined by binding of metal ions. The characterization will be done in the gas-phase with the use of a mass spectrometer and special techniques.