| dc.contributor.author | Anacleto, Joseph F. | en_US |
| dc.date.accessioned | 2014-10-21T12:36:58Z | |
| dc.date.available | 1993 | |
| dc.date.issued | 1993 | en_US |
| dc.identifier.other | AAINN93622 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10222/55373 | |
| dc.description | Four liquid chromatography-mass spectrometry (LC-MS) interfaces were evaluated for their ability to analyze complex mixtures of hish molecular weight polycyclic aromatic compounds (PAC). The moving belt interface permits the use of electron ionization (EI) since the mobile phase is removed before the analyte reaches the high vacuum ion source. This was particularly useful for the analysis of a carbon black extract since polycyclic aromatic hydrocarbons (PAH) produce intense molecular ions which are ideal for compound identification and enhanced sensitivity. | en_US |
| dc.description | The particle beam interface also allows the acquisition of EI mass spectra. The detection limits obtained with this interface were very poor in comparison to the other interfaces studied. Non-linear external calibration curves, which are characteristic of this interface, were also obtained for the analysis of PAH standards. | en_US |
| dc.description | The heated nebulizer interface, which uses atmospheric pressure chemical ionization (APCI), produces both molecular ions (M$\sp+\cdot$) and protonated molecules (MH$\sp+)$ of PAC. This ionization technique was particularly suited to the analysis of tar sand oil fractions since the highly alkylated PAC present in these samples produced simple spectra without the fragmentation observed with EI. The heated nebulizer interface was modified to also act as a supercritical fluid chromatography (SFC)-MS interface utilizing the same restrictor used in off-line experiments with a photoionization detector. | en_US |
| dc.description | The ionspray LC-MS interface was only capable of analyzing mixtures of nitrogen-containing PAC (or basic PAC) in acidic mobile phases because the ionization process (i.e., ion evaporation) requires the analyte to pre-form ions in solution. Alternative ionization techniques using this interface (e.g., charge-transfer complexation and electrochemical oxidation) were also investigated. | en_US |
| dc.description | Of the LC-MS interfaces studied, the heated nebulizer was clearly the best choice for PAC analyses, especially for the high molecular weight compounds that are not amenable to common gas chromatographic techniques. | en_US |
| dc.description | Thesis (Ph.D.)--Dalhousie University (Canada), 1993. | 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 | Chromatographic-mass spectrometric analysis of polycyclic aromatic compounds. | en_US |
| dc.type | text | en_US |
| dc.contributor.degree | Ph.D. | en_US |
