Indirect Detection of Explosive Vapours by Thermal Dissociation Cavity Ring-Down Spectroscopy

Simple item page
dc.contributor.advisorOsthoff, Hans D.
dc.contributor.authorTaha, Youssef Mohamad
dc.contributor.committeememberShi, Yujun
dc.contributor.committeememberThurbide, Kevin B.
dc.contributor.committeememberKim, Seonghwan
dc.contributor.committeememberHastie, Donald R.
dc.date2018-06
dc.date.accessioned2018-04-13T14:29:09Z
dc.date.available2018-04-13T14:29:09Z
dc.date.issued2018-04-12
dc.description.abstractThis thesis describes two explosive detection methods capable of detecting explosives indirectly in ambient air. The first of the explosive detection methods utilizes a platinum catalyst heated to 350 °C to catalyze the thermal dissociation of nitroaromatic explosives, such as 2,4,6 trinitrotolune (TNT), to NO2 prior to detection. The catalytic thermal dissociation (cTD) CRDS was found to have a (1s, 3σ) limit of detection (LOD) of 0.5 ppbv. The LOD was sufficient for the detection of TNT in ambient air but lacked the sensitivity to detect less volatile nitro aromatic explosives such as 2,4,6 trinitrophenylmethylnitramine (Tetryl). Efforts to improve the sensitivity of the instrument via a trap and purge pre-concentration scheme were of limited success largely due to poor sample recoveries from the Tenax traps used. The second explosive detection technique exploited radicals generated during the thermal decomposition of triacetone triperoxide (TATP), a peroxide explosive, for detection. These radicals were amplified via a peroxide radical chemical amplification scheme (PERCA) that required the addition of NO and a radical chain carrier, commonly CO, to generate NO2. A modelling study was conducted to assess alternative radical chain carriers as well as the effect of TD on amplification chemistry. Dimethyl ether and ethane were found to be appropriate chain carriers. Additionally, the modelling study suggested that elevated TD temperatures slow down radical chemistry and reduce chemical amplification (CL) while reducing the dependence of CL on relative humidity and radical sinks. A TD-PERCA-CRDS instrument was constructed and its temperature dependent chain length calibrated using peroxyacyl nitrates and peroxy nitric acid. The TD-PERCA-CRDS was found to have a CL up to 69±5 at 250 °C and an LOD (1s, 1σ) of 1.3 pptv. The instrument’s relative humidity dependence was reduced compared to that of room temperature PERCA but the instrument was found to suffer from an ozone interference at temperatures greater than 150 °C. A sample of TATP was synthesized in the lab and its identity and purity established using FTIR. TATP decomposition resulted in an NO2 signal that was 22±3 times larger than that expected from TATP saturation vapour pressure, and the LOD was 5 pptv.en_US
dc.identifier.citationTaha, Y. M. (2018). Indirect Detection of Explosive Vapours by Thermal Dissociation Cavity Ring-Down Spectroscopy (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/31780en_US
dc.identifier.doihttp://dx.doi.org/10.11575/PRISM/31780
dc.identifier.urihttp://hdl.handle.net/1880/106492
dc.language.isoeng
dc.publisher.facultyGraduate Studies
dc.publisher.facultyScience
dc.publisher.institutionUniversity of Calgaryen
dc.publisher.placeCalgaryen
dc.rightsUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.
dc.subjectChemistry
dc.subjectexplosive
dc.subjectCRDS
dc.subjectcavity ring-down spectroscopy
dc.subjectspectroscopy
dc.subjectTATP
dc.subjectTNT
dc.subject.classificationEducation--Sciencesen_US
dc.subject.classificationChemistry--Analyticalen_US
dc.subject.classificationAtmospheric Scienceen_US
dc.titleIndirect Detection of Explosive Vapours by Thermal Dissociation Cavity Ring-Down Spectroscopy
dc.typedoctoral thesis
thesis.degree.disciplineChemistry
thesis.degree.grantorUniversity of Calgary
thesis.degree.nameDoctor of Philosophy (PhD)
ucalgary.item.requestcopytrue
ucalgary.thesis.checklistI confirm that I have submitted all of the required forms to Faculty of Graduate Studies.en_US
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
ucalgary_2018_taha_youssef.pdf
Size:
4.42 MB
Format:
Adobe Portable Document Format
Description:
Download
License bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
license.txt
Size:
1.74 KB
Format:
Item-specific license agreed upon to submission
Description:
Download
Collections
Open Theses and Dissertations