Ion Hydration and New Structural Methods in Mass Spectrometry

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

With support from the Chemical Measurement and Imaging Program, Prof. Evan Williams and his group at the University of California - Berkeley are developing and applying new methods to investigate the structures of ions surrounded by a controlled number of solvent molecules. The goals are to understand how different ions can affect the solvent structure at both close and long range, and how solvent can affect the structures of ions. These experiments use state-of-the-art Fourier-transform ion cyclotron resonance mass spectrometry to produce, isolate, and store solvated ions at controlled temperatures. The structures of these ions are investigated using infrared radiation generated by tunable lasers. Resulting experimental data support models at the highest level of theory possible; these in turn may lead to an explanation for the widely studied, but poorly understood, Hofmeister series, in which ions are ordered based on their propensities to denature or stabilize protein conformations. These studies provide a foundation by which to understand how solvents (particularly water) interact with different functional groups in molecules and may lead to an improved understanding of protein function at the molecular level. Thus, the experiments can impact many different areas of science, including understanding how cells function, how drugs interact with drug targets (for discovery of new pharmaceuticals), how the efficiency of chemical reactions can be improved through better understanding of reaction intermediates and kinetics, and how solvent or other surrounding molecules can influence the chemistry of a molecule. Graduate and undergraduate students involved in these studies benefit from learning about and using new instrumentation and novel methods for molecular characterization. They also learn to effectively communicate their results by speaking at conferences and by writing papers for peer-reviewed journals. To introduce elementary school students to the capabilities of modern chemical instrumentation and to the concepts of atoms, molecules, atomic connectivity and molecular identification (thereby reinforcing basic math skills), it is planned to adapt a mass spectrometer to be run remotely. Additional experiments aimed at students at the high school level are planned.