Faculty of Graduate Studies
Graduate Programme in Chemistry
ORAL EXAMINATION PROSPECTUS
A Candidate for the Degree of
Master of Science.
Title of Thesis:
Method Development for the Sampling and Analysis of Atmospheric Nitrophenols
November 4, 2010 @ 1:30 pm – 2:15 pm
258 Petrie Science and Engineering Bldg.
York University
Abstract: Nitrophenols are primarily formed in the atmosphere by the OH-radical initiated photo-oxidation of aromatic hydrocarbons such as toluene. These compound specific products can be used to study the contribution of toluene oxidation to the formation of secondary particulate organic matter (POM) via stable carbon isotopic composition measurements. Recent studies of methylnitrophenols indicate that their concentration in the particle phase is substantially lower than expected from the atmospheric oxidation of the volatile organic compounds (VOC) precursors. One possible explanation for this discrepancy is that a substantial part of the methylnitrophenols remains in the gas phase, although these measurements are lacking due to the difficulty of separating the two phases from each other.
In this work a new method to determine the concentrations for the total amounts of gas and particle phase nitrophenols has been developed and validated. The measurements were done using quartz fibre filters that were coated with ground XAD-4 resin. With some modifications, the filters were found to work well with an extraction procedure previously developed for analysis of methylnitrophenols in PM samples. From atmospheric samples collected at YorkUniversity, six different phenols have been detected and quantified with this method. Moreover, tests confirm that the majority of the compounds do exist in the gas phase, and suggest that these compounds favourably partition into the gas phase. Unfortunately, it was found that the coated filters do not completely retain all the target compounds. Nevertheless, due to the adsorbing nature of the resin, larger sample masses of these compounds were obtained with the coated filters, which can allow isotopic composition measurements to be more readily attainable.