eprintid: 8868 rev_number: 5 userid: 6 dir: disk0/00/00/88/68 datestamp: 2011-11-10 19:56:55 lastmod: 2016-11-15 13:48:04 status_changed: 2011-11-10 19:56:55 type: thesis_degree metadata_visibility: show contact_email: thw5@pitt.edu item_issues_count: 0 eprint_status: archive creators_name: Watson, Thomas Harold creators_email: thw5@pitt.edu creators_id: THW5 title: THE FLOWING AFTERGLOW AS A CHEMICAL REACTIONMASS SPECTROMETER: ACCURACY DETERMINATIONS AND REAGENT IONDEVELOPMENT ispublished: unpub divisions: sch_as_chemistry full_text_status: public keywords: Mass Spectrometry abstract: Henry's Law was utilized to determine the accuracy of the flowing afterglow at the University of Pittsburgh as a Chemical Reaction Mass Spectrometer (CR-MS). H3O+ and its first three hydrates were utilized as reagent ions in the CR-MS technique to quantify headspace concentrations over multiple series of dilute aqueous acetone, acetonitrile, and benzaldehyde/THF solutions. The temperature corrected Henry's Law constants, kHθ, of acetone, acetonitrile, benzaldehyde, and THF were calculated as 32.1+3.3, 45.2+6.5, 41.6+2.1, and 14.8+1.0 M atm-1, respectively. These values for acetone, acetonitrile, benzaldehyde, and THF are in agreement within error of the literature values of 28+3, 51+3, 39+3, and 14 M atm-1, respectively. These measurements suggest that our flowing afterglow can be utilized to accurately quantify multiple VOCs simultaneously via the CR-MS technique. H3O+ is the most commonly utilized reagent ion for the CR-MS technique due to its many advantages. This ion possesses two main limitations; it readily clusters with water and cannot decipher between isobaric (of the same mass) molecules. Due to its size and tendency to react like a proton, the trimethylsilyl group (TMS+) can be substituted for a proton to reduce clustering. Substitution of the nitrosyl cation for a proton creates a NO+ donor and an ion that can decipher between isobaric molecules. The preparation of R((CH3)3Si)ONO+, where R is a proton, trimethylsilyl, alkyl, or NO+ moiety, was attempted in order to make a reagent ion that can decipher between isobaric molecules, does not cluster, and, yet, maintains the advantages of H3O+ as a reagent ion. There were four different preparations attempted for ions of this type: NO+ + methoxytrimethylsilane, NO+ + hexamethyldisiloxane, ((CH3)3Si)2OH+ + methyl nitrite, and ((CH3)3Si)OH2+ + methyl nitrite. The clean production of R((CH3)3Si)ONO+ remains elusive. The reactions of NO+ and methoxytrimethylsilane and NO+ and hexamethyldisiloxane resulted in hydride and/or methide abstraction. No reaction occurred between protonated hexamethyldisiloxane and methyl nitrite. The reaction of protonated trimethysilanol with methyl nitrite did not produce an ion of the type R((CH3)3Si)ONO+ cleanly as it resulted in H(TMS)ONO+ (m/z 120) and (CH3)(TMS)ONO+ (m/z 134). date: 2009-09-29 date_type: completed institution: University of Pittsburgh refereed: TRUE etdcommittee_type: committee_chair etdcommittee_type: committee_member etdcommittee_type: committee_member etdcommittee_name: Grabowski, Joseph J etdcommittee_name: Pratt, David etdcommittee_name: Jordan, Kenneth etdcommittee_email: joeg@pitt.edu etdcommittee_email: pratt@pitt.edu etdcommittee_email: jordan@pitt.edu etdcommittee_id: JOEG etdcommittee_id: PRATT etdcommittee_id: JORDAN etd_defense_date: 2009-08-11 etd_approval_date: 2009-09-29 etd_submission_date: 2009-08-03 etd_access_restriction: immediate etd_patent_pending: FALSE assigned_doi: doi:10.5195/pitt.etd.2011.8868 thesis_type: thesis degree: MS committee: Joseph J. Grabowski (joeg@pitt.edu) - Committee Chair committee: David Pratt (pratt@pitt.edu) - Committee Member committee: Kenneth Jordan (jordan@pitt.edu) - Committee Member etdurn: etd-08032009-200225 other_id: http://etd.library.pitt.edu/ETD/available/etd-08032009-200225/ other_id: etd-08032009-200225 citation: Watson, Thomas Harold (2009) THE FLOWING AFTERGLOW AS A CHEMICAL REACTIONMASS SPECTROMETER: ACCURACY DETERMINATIONS AND REAGENT IONDEVELOPMENT. Master's Thesis, University of Pittsburgh. (Unpublished) document_url: http://d-scholarship-dev.library.pitt.edu/8868/1/watsonth_etd2009.pdf