Multi-dimensional chromatographic methods for polycyclic aromatic compounds in complex environmental samples.
Date
2002
Authors
Potvin, Michael A.
Journal Title
Journal ISSN
Volume Title
Publisher
Dalhousie University
Abstract
Description
The research for this thesis was divided into two principal areas. This first area was concerned with the development of multi-dimensional chromatographic methods for the determination of polycyclic aromatic hydrocarbons (PAHs) in light gas oils. A two-dimensional liquid chromatography (LC)-gas chromatography (GC) (LC-GC) and three-dimensional LC procedures were developed. A two-dimensional LC-supercritical fluid chromatography (SFC) procedure was used to investigate the difference between the normal phase LC and SFC modes of operation. LC-GC was able to provide qualitative information about the aromatic class (by ultraviolet and fluorescence spectroscopy) and general levels of aliphatic substitution (by mass spectrometry). Three-dimensional LC was able to further expand on this information and added structural details. A light gas oil was found to contain aromatic species with 1 to 4 rings. There was no evidence for larger aromatic compounds. A series of phenanthrenes and pyrenes were identified that had an aliphatic ring substituent.
The second part of this research was concerned with the development of quantitative methods for the analysis of the priority PAHs and nitro-PAHs in diesel exhaust and air particulates. A two-dimensional procedure using a commercial aminopropyl column derivatized with 2,5-dinitrobenzenesulfonyl (DNBS) chloride was developed to clean-up samples prior to analysis by LC-fluorescence and GC-MS. A SFC separation was used to quantify nitro-PAHs by off-line reduction to the amines and by molecular fluorescence detection. Variable levels of PAHs and nitro-PAHs were found between diesel exhaust samples. The distribution of priority PAHs was found to be consistent for the Environment Canada diesel particulates collected from different buses. A more detailed analysis was not possible because sampling information was not provided with the filters from Environment Canada. The distribution of priority PAHs observed with the diesel exhaust particulates was different from that of an urban dust sample. Diesel particulates contained much larger concentrations of small aromatics while the urban dust showed higher levels of larger PAHs.
Thesis (Ph.D.)--Dalhousie University (Canada), 2002.
The second part of this research was concerned with the development of quantitative methods for the analysis of the priority PAHs and nitro-PAHs in diesel exhaust and air particulates. A two-dimensional procedure using a commercial aminopropyl column derivatized with 2,5-dinitrobenzenesulfonyl (DNBS) chloride was developed to clean-up samples prior to analysis by LC-fluorescence and GC-MS. A SFC separation was used to quantify nitro-PAHs by off-line reduction to the amines and by molecular fluorescence detection. Variable levels of PAHs and nitro-PAHs were found between diesel exhaust samples. The distribution of priority PAHs was found to be consistent for the Environment Canada diesel particulates collected from different buses. A more detailed analysis was not possible because sampling information was not provided with the filters from Environment Canada. The distribution of priority PAHs observed with the diesel exhaust particulates was different from that of an urban dust sample. Diesel particulates contained much larger concentrations of small aromatics while the urban dust showed higher levels of larger PAHs.
Thesis (Ph.D.)--Dalhousie University (Canada), 2002.
Keywords
Chemistry, Analytical., Environmental Sciences.