Characterization of Fast Dissociation Pathways of Polyatomic Ions

University Of Arizona, Tucson AZ

Investigators

Abstract

Professor Vicki Wysocki of the University of Arizona is supported by the Analytical and Surface Chemistry Program to study the fast fragmentation of peptides. The fundamental question in this work is one that asks why we are able to see significant fragmentation on the timescale of the typical mass spectrometry experiment, while the best theory available suggests that fragments should only be observed with longer timescale MS experiments. The overall hypothesis is that there are fast fragmentation pathways (via previously undescribed reactive intermediates) that lead to the appearance of products on timescales that allow observation by mass spectrometers with microsecond or shorter experimental timeframes. The PI uses surface collisions in combination with matrix-assisted laser desorption ionization (and later electrospray ionization) and time-of-flight mass spectrometry to probe these processes. The question is studied by varying both the nature of the surface and the nature of the projectiles. There is a well-established collaboration with the Futrell group at PNNL and the theorist Hase at Texas Tech. Students are well-trained in physical-analytical chemistry and mass spectrometry. Fragmentation of peptides is commonly used in proteomics, in which mass spectrometry plays a critical role. Understanding fragmentation at a fundamental level can lead to more efficient analytical instruments, and predictive models for database purposes.