Evaluation of Binding Interactions of Ions Generated by Electrospray Ionization

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This project is in the area of analytical and surface chemistry and in the subfield of mass spectrometry. During the tenure of this three-year continuing grant, Professor Brodbelt and her students at the University of Texas at Austin will carry out a systematic comparative examination of ion complexes formed by collisionally induced dissociation (CID) and cationization by chemical ionization (CI) with their analogues formed directly by electrospray ionization (ESI). These studies are designed to identify the chemical processes that impact ion formation and to provide insights into the molecular interactions that give rise to the significant differences in ion fragmentation patterns observed between ESI and softer ionization processes such as CID and CI. Additionally, the relative cation-substrate binding strengths will be correlated with substrate structural characteristics, including the presence of specific functional groups and steric features. In addition to providing new fundamental insights into ion formation processes, this research is expected to lead to improvements in the analytical utility of ESI-based mass spectrometry. Electrospray ionization is the most rapidly growing ionization technique in analytical mass spectrometry. It is a robust ionization technique and the requisite equipment is simple and relatively inexpensive. However, ion fragmentation patterns obtained with ESI, a "harsh" ionization method, differ significantly from those observed with "softer" ionization methods such as CID and CI. This research is aimed at understanding the chemical processes attendant to the ion formation event and thereby extend the scope and sensitivity of ESI-based mass spectrometry as an analytical tool.