Document Type

Dissertation

Degree

Doctor of Philosophy (PhD)

Department

Chemistry

First Advisor's Name

Piero Gardinali

First Advisor's Committee Title

Major Professor

Second Advisor's Name

Rudolf Jaffe

Second Advisor's Committee Title

Committee Member

Third Advisor's Name

Yong Cai

Third Advisor's Committee Title

Committee Member

Fourth Advisor's Name

Berrin Tansel

Fourth Advisor's Committee Title

Committee Member

Fifth Advisor's Name

Stanislaw Wnuk

Fifth Advisor's Committee Title

Committee Member

Keywords

High-resolution mass spectrometry, crude oil, wastewater, non-target analysis

Date of Defense

11-14-2016

Abstract

The advancements in the field of analytical chemistry, and especially mass spectrometry, have been redefining the field of contaminant detection. While more traditional analysis was sufficient to screen for a small number of well-known compounds, new techniques such as high-resolution mass spectrometry, have enabled a fairly comprehensive screening for previously unknown contaminants. This is enormously beneficial with respect to the analysis of water, air, or soil quality in a society that continuously introduces novel anthropogenic compounds into the environment. This dissertation, thus, focused on the analysis of the uncharacterized portion of compounds in two types of complex environmental matrices (i.e., crude oil and wastewater).

First, targeted and non-targeted analyses were used in order to characterize a crude oil weathering series. Traditional techniques were used for the analysis of well-known oil components and led to the confirmation of biodegradation and photo-degradation trends. An ultrahigh-resolution mass spectrometric analysis was carried out in conjunction with several visualization plots in order to search for unknown compounds. While the study successfully detected a drastic increase in oxygenated components (likely ketones, quinones, and carboxylic acids), it also revealed severe limitations in the state of the art non-targeted crude oil analysis. Some of these limitations were explored in an in-depth atmospheric pressure ionization study of model petroleum compounds, and the dependence of ionization efficiency on numerous factors (e.g., size, heteroatom content, and methylation level) was shown. Since disregarding these intrinsic limitations leads to severely biased conclusions, these results provide crucial information for future crude oil characterization studies. Lastly, suspected and non-targeted analyses were used to evaluate contamination levels in wastewater-impacted interrelated water samples. A significant number of persistent compounds were tentatively identified, which represents an area of environmental concern that needs to be addressed further.

Overall, this dissertation successfully applied non-targeted (in addition to targeted) analysis in order to screen for non-characterized compounds in crude oil and wastewater affected water samples. By doing so, the great potential of the growing field of non-targeted screening in order to expand the range of contaminants to include previously unknown and emerging compounds was highlighted.

Identifier

FIDC001186

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