Development of a field portable mass spectrometer for quantitative analysis of volatile organic compounds in air
Date
2016-04-26
Authors
Davey, Nicholas
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Abstract
The typical strategy for atmospheric analysis of volatile organic compounds
(VOCs), is to collect discrete samples which are then transported to a laboratory for
analysis. This method has limited spatial and temporal resolution, and can be both
costly and time consuming. To overcome these limitations, a mobile monitoring
platform was developed for real-time quantitative chemical analysis. This work
describes the development of membrane introduction mass spectrometer and
identi es the necessary requirements to make a reliable and e ective instrument for
in-situ chemical analysis. These include, the integration of a membrane interface
with a miniaturized mass spectrometer, development of a data management
strategy, reducing the e ects of isobaric interferences and employing an internal
standard for quantitative measurements. Furthermore, the negative e ects of
environmental variables, such as the Earth's magnetic eld, were examined and
e ectively eliminated. In addition, this work demonstrates quantitative mapping of
atmospheric VOCs in real-time, which allows rapid identi cation of chemical plumes
and therefore, areas of potential concern. Both lab and eld-based comparisons of
iv
membrane introduction mass spectrometer data and traditional whole air sampling
canister data were undertaken. The primary eld site was near Ft. McMurray, AB
where baseline data was collected around a steam assisted gravity drainage (SAGD)
facility and surrounding public roads. Monitoring for fugitive emissions at this
facility and surrounding bitumen mining and processing operations is demonstrated.
Field data were also obtained, near an industrial site in Ft.Saskatchewan, AB, that
demonstrate the e cacy of an adaptive sampling strategy. Finally, chemical
ionization was investigated as a soft ionization strategy to improve chemical
selectivity for the analysis of complex hydrocarbon mixtures. The development of an
in-line liquid chemical ionization reagent delivery system is presented and proposed
as an e ective strategy for eliminating interferences arising from biogenic terpenes
and alkyl aromatics. In all, this thesis presents the design and implementation of a
mobile membrane introduction mass spectrometer for atmospheric chemical
analysis. Results that improve performance and demonstrate the novelty of the
data-type are provided, along with avenues for future development.
Description
Keywords
atmospheric chemical analysis, ion-molecule reactions, membrane introduction mass spectrometry (MIMS), real time quantitative mapping