Levis, Robert J.; Strongin, Daniel R.; Schafmeister, Christian; Amini, Shohreh (Temple University. Libraries, 2011)
      The use of femtosecond (fs) laser pulses in laser-induced breakdown spectroscopy (LIBS) and for chemical analysis using mass spectrometry is explored. A comparison of fs-LIBS and remote filament-induced breakdown spectroscopy (R-FIBS) in the analysis of graphite composites yielded more accurate results with filaments due to intensity clamping within the filament. The investigation of fs-LIBS and R-FIBS in the detection of explosives led to the discovery of femtosecond vaporization of intact molecules under ambient conditions. This knowledge was then used in the development of a new ambient laser-based mass analysis technique. The combination of nonresonant femtosecond laser vaporization with electrospray post-ionization called laser electrospray mass spectrometry (LEMS) was investigated as a universal detection method of pharmaceuticals, biological macromolecules and plant tissues. We show the capability of femtosecond lasers to desorb sample without any sample preparation or resonant transition in the sample or substrate. Ambient mass spectral imaging and tissue type classification is also demonstrated.