Semester

Spring

Date of Graduation

2014

Document Type

Dissertation

Degree Type

PhD

College

Eberly College of Arts and Sciences

Department

Chemistry

Committee Chair

Glen P. Jackson

Committee Co-Chair

Suzanne C. Bell

Committee Member

Patrick S. Callery

Committee Member

Harry O. Finklea

Committee Member

Stephen J. Valentine

Abstract

Recent developments in analytical instrumentation have allowed scientists to investigate systems that were unattainable in the past. In the biomedical community this increase in investigative power has allowed the exploration of biological components like proteins, lipids, and DNA and their role in the many different cycles necessary for human life. By understanding the nuances of these processes, medical professionals can more easily recognize the products of mutations or malfunctions that can lead to more accurate prognosis and diagnosis of disease. Typically, lipids are analyzed through hyphenated chromatography-mass spectrometry instruments and especially using collision-induced dissociation (CID). Low-energy CID typically produces both headgroup and complete fatty acid chain loss, whereas high energy CID causes extensive fatty acid chain fragmentation. High energy CID is less widespread, so researchers continually investigate alternate techniques like alkali metallation and multi-stage mass spectrometry to probe the structure of diverse classes of lipids.;Through this work we seek to contribute to this advancement of the biomedical field through the development of a new mass spectrometric fragmentation technique known as metastable atom activated dissociation (MAD). The application of this technique to biological molecules has been demonstrated in the past through peptides, but this is the first application to lipid ions. MAD functions by exposing isolated and stored lipid ions with a beam of high-energy helium metastable atoms. Penning ionization of the lipid ions causes fragmentation throughout the lipid molecules and provides many radical-induced and high-energy products that are not typically observed through collisional activation. MAD is therefore useful in that it can generate high energy fragmentation products in a low-energy environment, like an ion trap, causing unique and extensive fragmentation of lipid molecules without the need for alternate sample preparation steps or multiple stages of mass spectrometry. These abilities allow MAD to contribute unique information about lipid species using a technique that is easy to perform and built using mass spectrometry hardware common to many laboratories. The combination of MAD with other traditional or experimental fragmentation techniques may allow for more informative analysis and a more complete understanding of lipid functionality.;This dissertation also describes the application of a new ambient ionization technique known as laser ablation electrospray ionization (LAESI) to drug identification in a variety of forensically relevant matrices. Currently, the most popular technique for confirmatory analysis in crime laboratories is gas chromatography mass spectrometry (GC/MS). However, the slow analysis times and extensive sample preparation steps have caused significant backlogs in forensic labs. Through this work it was determined that LAESI-MS/MS could successfully detect a wide range of drugs of abuse in various media including solutions, hair, and plant matter. LAESI-MS/MS was able to identify the presence of each drug in the test set at both 1 mg/mL and 5 mg/mL except phenobarbital, which was only identified at 1 mg/mL. LAESI-MS/MS was also able to identify these drugs in solutions in which a presumptive color test had been performed. In hair and plant samples LAESI-MS/MS was able to identify drugs at biologically relevant levels. Data from these analysis could also be used to generate 2-D ion maps showing the distribution of the drug across the samples. The rapid analysis time of ~5 s per sample and minimal sample preparation make LAESI-MS/MS a potential candidate for reducing backlogs in crime labs.

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