| dc.contributor.author | Lin, Zhong-Ping. | en_US |
| dc.date.accessioned | 2014-10-21T12:38:09Z | |
| dc.date.available | 1998 | |
| dc.date.issued | 1998 | en_US |
| dc.identifier.other | AAINQ36559 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10222/55570 | |
| dc.description | Certain types of aroyl compounds produce gas-phase luminescence in excited nitrogen. A novel, radioactively stimulated, high-voltage, low-current discharge in high-purity nitrogen was used to excite aroyl compounds. Based on gas-phase luminescence, a new single-channel aroyl luminescence detector (ALD) was designed and constructed. Aroyl compounds can be detected with unique selectivity and extreme sensitivity in the ALD. The detection limit was about 0.1 femtomol/second for a strongly luminescing compound like benzaldehyde. The linear range of calibration curves was about 4 orders of magnitude. | en_US |
| dc.description | The gas-phase luminescence spectra of about sixty aroyl compounds were mapped. Gas-phase phosphorescence spectra are rare in the literature but, where available, they agreed with the ALD spectra. Our speculative luminescence mechanism for aroyl compounds in excited nitrogen suggests that ground-state N2 is excited by collision with a fast electron in the mild discharge, and that this is followed by efficient triplet-triplet energy transfer from N2A 3Su+ to the aroyl compound. | en_US |
| dc.description | The single-channel ALD was converted to dual-channel operation to demonstrate the possibility of computer-mediated, compound-specific detection by dual-channel photometry. Response ratios of sixteen components of test mixture were examined, and turned out to remain constant in the ALD from close to their limit of detection to well beyond their range of linear calibration. Each individual compound could be successfully retrieved from the chromatographic file of the separated mixture as a single-peak Condac chromatogram in the presence, and even in the absence, of an optical filter or dispersive device. | en_US |
| dc.description | Finally, a triple-channel aroyl luminescence detector was designed and constructed. It can be used to acquire gas-phase luminescence spectra from a single chromatographic peak and generate response ratios of aroyl compounds. Based on the spectrum, retention time and spectral response ratio, particular aroyl compounds can be identified in complex mixtures. They can also be quantitatively determined with high sensitivity (picogram range) in a non-dispersive channel. This methodology was employed to analyze some aroyl compounds in essential oils and complex environmental samples such as a standard marine sediment. Further demonstrated analytical applicabilities include the highly sensitive and selective determination of alcohols coupled with luminescing aroyl moiety, and the direct-injection sampling of room air for luminescing products of incomplete combustion. (Abstract shortened by UMI.) | en_US |
| dc.description | Thesis (Ph.D.)--Dalhousie University (Canada), 1998. | en_US |
| dc.language | eng | en_US |
| dc.publisher | Dalhousie University | en_US |
| dc.publisher | | en_US |
| dc.subject | Chemistry, Analytical. | en_US |
| dc.subject | Chemistry, Organic. | en_US |
| dc.title | Gas-phase luminescence of aromatic carbonyl compounds and the design and use of a gas chromatographic detector. | en_US |
| dc.type | text | en_US |
| dc.contributor.degree | Ph.D. | en_US |
