This dissertation details the design and implementation of a state-of-the-art ambient trace analysis technique known as laser electrospray mass spectrometry. This novel technique utilizes an intense, nonresonant femtosecond laser pulse to transfer nonvolatile, fragile molecules into the gas phase from various substrates. The vaporized analyte is subsequently captured, solvated and ionized in an electrospray plume enabling mass analysis. Laser electrospray mass spectrometry is capable of analyzing samples in the liquid or solid states, mass spectral imaging of adsorbed molecules and detecting low vapor pressure analytes remotely. Experiments with biomolecules and pharmaceuticals, such as vitamin B12 and oxycodone, have demonstrated that the nonresonant femtosecond laser pulse allows for coupling into and vaporization of all molecules. This implies that sample preparation (elution, mixing with matrix and choosing samples with a particular electronic or vibrational transition) is not necessary, thus creating a universal mass analysis technique. Investigations using low vapor pressure molecules, such as lipids and proteins, led to the discovery that unfragmented molecules are transferred into the gas phase via a nonthermal mechanism. The laser electrospray mass spectrometry technique has allowed for the nonresonant femtosecond laser vaporization and mass analysis of trace amounts of a nitro-based explosive from a metal surface. The vaporization of unfragmented explosive molecules from a surface facilitates the identification of the explosive, reducing the probability of false positives and false negatives. In addition, this "soft" vaporization of molecules using nonresonant femtosecond laser pulses allows for protein to be transferred from the condensed phase into the gas phase without altering the molecule's structure, enabling ex vivo conformational analysis and possible disease typing. / Chemistry
| Identifer | oai:union.ndltd.org:TEMPLE/oai:scholarshare.temple.edu:20.500.12613/846 |
| Date | January 2011 |
| Creators | Brady, John Joseph |
| Contributors | Levis, Robert J., Owens, Kevin Glenn, 1960-, Strongin, Daniel R., Matsika, Spiridoula |
| Publisher | Temple University. Libraries |
| Source Sets | Temple University |
| Language | English |
| Detected Language | English |
| Type | Thesis/Dissertation, Text |
| Format | 218 pages |
| Rights | IN COPYRIGHT- This Rights Statement can be used for an Item that is in copyright. Using this statement implies that the organization making this Item available has determined that the Item is in copyright and either is the rights-holder, has obtained permission from the rights-holder(s) to make their Work(s) available, or makes the Item available under an exception or limitation to copyright (including Fair Use) that entitles it to make the Item available., http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | http://dx.doi.org/10.34944/dspace/828, Theses and Dissertations |
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