Non-Targeted Analysis of Petroleum Metabolites in
Groundwater Using GC×GC–TOFMS
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Abstract
Groundwater at fuel
release sites often contains nonpolar hydrocarbons
that originate from both the fuel release and other environmental
sources, as well as polar metabolites of petroleum biodegradation.
These compounds, along with other polar artifacts, can be quantified
as “total petroleum hydrocarbons” using USEPA Methods
3510/8015B, unless a silica gel cleanup step is used to separate nonpolar
hydrocarbons from polar compounds prior to analysis. Only a limited
number of these metabolites have been identified by traditional GC–MS
methods, because they are difficult to resolve using single-column
configurations. Additionally, the targeted use of derivatization limits
the detection of many potential metabolites of interest. The objective
of this research was to develop a nontargeted GC×GC–TOFMS
approach to characterize petroleum metabolites in environmental samples
gathered from fuel release sites. The method tentatively identified
more than 760 unique polar compounds, including acids/esters, alcohols,
phenols, ketones, and aldehydes, from 22 groundwater samples collected
at five sites. Standards for 28 polar compounds indicate that effective
limits of quantitation for most of these compounds in the groundwater
samples range from 1 to 11 μg/L