Pulsed Laser Desorption in Supersonic Beam Spectroscopy/ Mass Spectrometry

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This project is in the general area of analytical and surface chemistry and in the subfields of laser spectroscopy and mass spectrometry. The thrust of this experimental activity is the development of new, highly selective methods of analysis for nonvolatile, thermally labile molecules, primarily biologically interesting ones. To accomplish this end, neutral molecules are desorbed from surfaces into the gas phase whereupon they are cooled through supersonic jet expansion which reduces their internal energy. Once cooled, these molecules exhibit quite sharp-featured electronic spectra. These sharp features enable the highly selective application of resonant two-photon ionization techniques which are used to ionize these molecules for subsequent analysis by time-of-flight mass spectrometry. This combination of laser desorption, supersonic jet expansion, resonant two-photon ionization, and mass spectrometry affords a sensitive, highly selective analytical tool for the qualitative and quantitative characterization of a broad spectrum of samples. Whereas this hybrid approach will be primarily focussed on the analysis of biomolecules of pharmaceutical and clinical interest such as catecholamines, indolamines, and small polypeptides, the results of this research are can be expected to impact broadly in the chemical, biological, and materials sciences.