The quantitative analysis of environmental and toxicological samples must be reliable, rapid, and in some cases field portable. In the United States, the employment of chemical weapons by rogue states and/or terrorist organizations is an ongoing concern. Nerve agent degradative products (methylphosphonic acid) as well as surrogates (glyphosate) must be detected at low quantities in various water matrices. Current methods involve tedious and time-consuming derivatizations for gas chromatography-mass spectrometry and liquid chromatography in tandem with mass spectrometry. Two solid phase extraction (SPE) techniques for the analysis of glyphosate and methylphosphonic acid are described with the utilization of isotopically enriched analytes for quantitation using atmospheric pressure chemical ionization-quadrupole-time of flight-mass spectrometry (APCI-Q-TOF-MS) that does not require derivatization.
<br>The use of illicit drugs is also an increasing problem in the United States. Toxicological analysis of illicit drugs is important for death investigation as well as in the treatment of individuals who abuse and misuse drugs. This dissertation describes a newly developed analytical method for the simultaneous quantitative analysis of heroin, 6-acetylmorphine, morphine, cocaine, codeine, methadone, and fentanyl in synthetic urine. The resolution of an electrospray ionization-time of flight-mass spectrometer (ESI-TOF-MS) was utilized for simultaneous analysis of the drugs after extraction from urine using two newly developed SPE procedures.
<br>The first SPE technique described in this dissertation is solid phase extraction-isotope dilution mass spectrometry (SPE-IDMS). It involves applying EPA Method 6800 in which a naturally occurring sample is pre-equilibrated with an isotopically enriched standard prior to SPE. The second extraction method, i-Spike, involves loading an isotopically enriched standard onto a SPE column independently from the naturally occurring sample. The sample and the spike are then co-eluted from the column enabling precise and accurate quantitation by molecular IDMS calculations. The SPE methods, in conjunction with IDMS, eliminate concerns of incomplete elution, matrix and sorbent effects, and MS drift. For accurate quantitation with IDMS, the isotopic contribution of all atoms in the target molecule must be statistically taken into account. This dissertation describes two newly developed sample preparation techniques for the analysis of environmental and toxicological samples as well as statistical probability analysis for accurate molecular IDMS. / Bayer School of Natural and Environmental Sciences / Chemistry and Biochemistry / PhD / Dissertation
| Identifer | oai:union.ndltd.org:DUQUESNE/oai:digital.library.duq.edu:etd/154096 |
| Date | 30 January 2012 |
| Creators | Wagner, Rebecca |
| Contributors | H. M. Skip Kingston, Stephanie J. Wetzel, Ellen S. Gawalt, Frederick Fochtman |
| Source Sets | Duquesne University |
| Detected Language | English |
| Rights | One year embargo: no access to PDF file until release date by author request. |
Page generated in 0.0114 seconds