ANYL 323 |
| Tandem Mass Spectrometry--the study of consecutive unimolecular or biomolecular reactions by multiple stages of mass analysis--has played a pivotal role in understanding the chemistry and physics of gas phase ions. Initially developed as a means for investigating reaction mechanisms, kinetics and dynamics of ion-molecule reactions, tandem mass spectrometry is now widely applied in chemistry, biology, materials science, aeronomy, environmental science and medicine. Current fundamental research in mass spectrometry emphasizes complex molecular ions, particularly ionized biomolecules. For such ions fragmentation is severely constrained by two factors. Energy transfer in collisions decreases in inverse proportion to ion mass and the dramatic increase in density of states with complexity of the ion decreases the rate of dissociation of energized ions by orders of magnitude. Consequently multiple gas phase collisions or multiple photon absorption is required to dissociate complex ions in the time frame sampled by mass spectrometers. An attractive alternative is ion surface collisions with special semiconductor surfaces - specifically, with self-assembled monolayers on a metal substrate. In this method a single sub-picosecond collision is sufficient to excite complex ions to arbitrarily high energies. Collision energy and time-resolved studies with RRKM-modeling of their dissociation behavior enables deduction of detailed kinetic parameters for low energy decomposition pathways. At higher energy, and for more complex peptides, transition to a shattering mechanism opens a variety of dissociation channels that are not accessible by multiple-collision or multi-photon excitation. Changing the nature of the self-assembled monolayer surface significantly alters energy transfer efficiency and the efficiency of capture of intact biomolecular ions on the surface. In this report early developments in tandem mass spectrometry will be summarized along with an overview of our recent investigations of surface-induced dissociation. |
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Frank H. Field and Joe L. Franklin Award for Outstanding Achievement in Mass Spectrometry in Honor of Jean H. Futrell
8:30 AM-12:20 PM, Tuesday, August 21, 2007 BCEC -- 104B, Oral
Division of Analytical Chemistry |