Robert K. Nelson

Woods Hole Oceanographic Institution

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Christopher M. Reddy

Woods Hole Oceanographic Institution

131

David L. Valentine

University of California, Santa Barbara

Christoph Aeppli

Bigelow Laboratory for Ocean Sciences

J. Samuel Arey

ExxonMobil (United States)

G. Todd Ventura

Saint Mary's University

Oliver C. Mullins

Schlumberger (United States)

Karin L. Lemkau

Western Washington University

Kliti Grice

Curtin University

Catherine A. Carmichael

Woods Hole Oceanographic Institution

Glenn S. Frysinger

United States Coast Guard Academy

Cooperative Institutions

Woods Hole Oceanographic Institution

110

Massachusetts Institute of Technology

Florida State University

University of California, Santa Barbara

National High Magnetic Field Laboratory

Schlumberger (British Virgin Islands)

Universidade Federal do Ceará

Schlumberger (United States)

Texas A&M University

United States Geological Survey

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A One-Pot/Single-Analysis Approach to Substrate Scope Investigations Using Comprehensive Two-Dimensional Gas Chromatography (GC×GC)

The Journal of Organic Chemistry (2016)

Gregory W. O’Neil Robert K. Nelson Alicia M. Wright Christopher M. Reddy

A representative substrate scope investigation for an enantioselective catalytic ketone-reduction has been performed as a single reaction on a mixture containing equimolar amounts of nine (9) prototypical compounds. The resulting analyte pool containing 18 potential products from nine different reactions could all be completely resolved in a single chromatographic injection using comprehensive two-dimensional gas chromatography (GC×GC) with time-of-flight mass spectrometry, allowing for simultaneous determination of percent conversion and enantiomeric excess for each substrate. The results obtained for an enantioselective iron-catalyzed asymmetric transfer hydrogenation using this one-pot/single-analysis approach were similar to those reported for the individualized reactions, demonstrating the utility of this strategy for streamlining substrate scope investigations. Moreover, for this particular catalyst, activity and selectivity were not greatly affected by the presence of other ketones or enantioenriched reduced products. This approach allows for faster and greener analyses that are central to new reaction development, as well as an opportunity to gain further insights into other established transformations.

Enantiomeric excess

Scope (computer science)

10.1021/acs.joc.6b00050

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Citations (2)

Hydroxyapatite catalyzed hydrothermal liquefaction transforms food waste from an environmental liability to renewable fuel

iScience (2022)

Heather O. LeClerc Geoffrey A. Tompsett Alex D. Paulsen Amy M. McKenna Sydney F. Niles

Food waste is an abundant and inexpensive resource for the production of renewable fuels. Biocrude yields obtained from hydrothermal liquefaction (HTL) of food waste can be boosted using hydroxyapatite (HAP) as an inexpensive and abundant catalyst. Combining HAP with an inexpensive homogeneous base increased biocrude yield from 14 ± 1 to 37 ± 3%, resulting in the recovery of 49 ± 2% of the energy contained in the food waste feed. Detailed product analysis revealed the importance of fatty-acid oligomerization during biocrude formation, highlighting the role of acid-base catalysts in promoting condensation reactions. Economic and environmental analysis found that the new technology has the potential to reduce US greenhouse gas emissions by 2.6% while producing renewable diesel with a minimum fuel selling price of $1.06/GGE. HAP can play a role in transforming food waste from a liability to a renewable fuel.

Hydrothermal liquefaction

Renewable resource

Food Waste

Renewable Fuels

Green waste

10.1016/j.isci.2022.104916

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Citations (15)

The West Falmouth Oil Spill: ∼100 Kg of Oil Found to Persist Decades Later

Environmental Forensics (2005)

Emily E. Peacock Robert K. Nelson Andrew R. Solow Joseph D. Warren Jessica L. Baker

In order to investigate the long-term fate of petroleum hydrocarbons in salt marsh sediments in Wild Harbor (West Falmouth, MA) impacted by the Florida spill of 1969, 26 sediment cores were collected and analyzed for total petroleum hydrocarbons (TPH). The results from this effort indicate that the distribution of petroleum hydrocarbons is spatially heterogeneous, oil compounds are generally located at sediment depths of 4 to 20 cm in areas closest to the banks of the marsh, and ∼ 100 kg of petroleum residues can be found to persist in intertidal sediments that were originally the most impacted.

Salt marsh

10.1080/15275920500194480

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Citations (38)

Examining Inputs of Biogenic and Oil-Derived Hydrocarbons in Surface Waters Following the Deepwater Horizon Oil Spill

ACS Earth and Space Chemistry (2019)

Helen K. White Charles T. Marx David L. Valentine Charles M. Sharpless Christoph Aeppli

Aliphatic hydrocarbons in the surface ocean are derived from phytoplankton and oil, but the coexistence and cycling of these two sources is not well-defined. Moreover, phytoplankton and oil can create thin layers of a nonmiscible phase that appear as sheens on surface water and are visually difficult to distinguish. Here, we examine the co-occurrence of hydrocarbon compounds in surface water samples to determine the inputs from phytoplankton and oil using pentadecane (C15-n-alkane) and heptadecane (C17-n-alkane) as molecular markers. Surface water sheens collected from a 2015 field survey in the Northern Gulf of Mexico contained hydrocarbons from natural oil seepage, phytoplankton blooms (i.e., biogenic), and mixtures of the two. Microbial communities examined in surface water sheen samples were dominated by cyanobacteria of the Genus Trichodesmium. The hydrocarbon content of the field-collected surface sheens was used to inform the categorization of 2171 samples collected in 2010 during the Deepwater Horizon (DWH) oil spill. Of the water samples categorized, a small fraction (<1%) contained only biogenic hydrocarbons, and ∼10% contained a biogenic-hydrocarbon input mixed with oil. This study provides a method for identifying biogenic inputs to oil slicks and surface sheens, and highlights a molecular approach to distinguish the two sources.

Deepwater Horizon

Alkane

Thermokarst

Heptadecane

10.1021/acsearthspacechem.9b00090

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Citations (11)

Long-term weathering and continued oxidation of oil residues from the Deepwater Horizon spill

Marine Pollution Bulletin (2016)

Helen K. White Chloe H. Wang Patrick Williams David M. Findley Alana M. Thurston

Deepwater Horizon

Flame ionization detector

10.1016/j.marpolbul.2016.10.029

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Citations (47)

Ocean Dumping of Containerized DDT Waste Was a Sloppy Process

Environmental Science & Technology (2019)

Veronika Kivenson Karin L. Lemkau Oscar Pizarro D. Yoerger Carl L. Kaiser

Industrial-scale dumping of organic waste to the deep ocean was once common practice, leaving a legacy of chemical pollution for which a paucity of information exists. Using a nested approach with autonomous and remotely operated underwater vehicles, a dumpsite offshore California was surveyed and sampled. Discarded waste containers littered the site and structured the suboxic benthic environment. Dichlorodiphenyltrichloroethane (DDT) was reportedly dumped in the area, and sediment analysis revealed substantial variability in concentrations of p,p-DDT and its analogs, with a peak concentration of 257 μg g–1, ∼40 times greater than the highest level of surface sediment contamination at the nearby DDT Superfund site. The occurrence of a conspicuous hydrocarbon mixture suggests that multiple petroleum distillates, potentially used in DDT manufacture, contributed to the waste stream. Application of a two end-member mixing model with DDTs and polychlorinated biphenyls enabled source differentiation between shelf discharge versus containerized waste. Ocean dumping was found to be the major source of DDT to more than 3000 km2 of the region's deep seafloor. These results reveal that ocean dumping of containerized DDT waste was inherently sloppy, with the contents readily breaching containment and leading to regional scale contamination of the deep benthos.

Dumping

10.1021/acs.est.8b05859

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Citations (38)

Molecular and Isotopic Analysis of Motor Oil from a Biodiesel-Driven Vehicle

Energy & Fuels (2010)

Emily E. Peacock J. Samuel Arey Jared A. DeMello Ann P. McNichol Robert K. Nelson

Biodiesel, a mixture of fatty acid methyl esters (FAMEs), is increasingly recognized as a renewable fuel. While some environmental impacts of biodiesel usage have been investigated, accumulation of organic compounds in motor oil, which can subsequently leak onto roads, has not been studied. Because studies have shown that toxic polycyclic aromatic hydrocarbons (PAHs) accumulate in the motor oil of engines fueled with fossil diesel or gasoline, the objective of this study was to determine if this also occurs for engines fueled with biodiesel. Here, we sampled and analyzed motor oil of a biodiesel-powered 2005 Volkswagen Passat Wagon over 3240 km of personal-use driving. Using gas chromatography with flame ionization detection (GC−FID), we found a total of 0.5% FAMEs in the motor oil after 3240 km. We also used gas chromatography−mass spectrometry and comprehensive two-dimensional gas chromatography and did not detect PAHs or other organic compounds not present in the initial motor oil. Using natural radiocarbon analysis, a powerful technique capable of detecting biodiesel-derived carbon that would be otherwise undetectable by gas chromatography, we found a total of 0.68% biodiesel-derived carbon after 3240 km. This is similar to the amount of FAMEs found in these samples with GC−FID, indicating that the primary source of biodiesel-derived carbon in the motor oil is FAMEs (and not PAHs or other carbonaceous species). This result suggests that used motor oil of biodiesel vehicles can be less toxic based on PAH content than vehicles fueled with fossil diesel or gasoline.

Flame ionization detector

Motor fuel

Renewable Fuels

Motor oil

10.1021/ef9011388

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Citations (9)

Society of souls: Spirit, friendship, and the antebellum reform imagination

Robert K. Nelson

10.21220/s2-k8cw-k176

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Citations (0)

Expansion of the Analytical Window for Oil Spill Characterization by Ultrahigh Resolution Mass Spectrometry: Beyond Gas Chromatography

Environmental Science & Technology (2013)

Amy M. McKenna Robert K. Nelson Christopher M. Reddy J. Savory Nathan K. Kaiser

Traditional tools for routine environmental analysis and forensic chemistry of petroleum have relied almost exclusively on gas chromatography–mass spectrometry (GC-MS), although many compounds in crude oil (and its transformation products) are not chromatographically separated or amenable to GC-MS due to volatility. To enhance current and future studies on the fate, transport, and fingerprinting of the Macondo well oil released from the 2010 Deepwater Horizon disaster, we created an extensive molecular library of the unadulterated petroleum to compare to a tar ball collected on the beach of Louisiana. We apply ultrahigh resolution Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry to identify compositional changes at the molecular level between native and weathered crude oil samples and reveal enrichment in polar compounds inaccessible by GC-based characterization. The outlined approach provides unprecedented detail with the potential to enhance insight into the environmental fate of spilled oil, improved toxicology, molecular modeling of biotic/abiotic weathering, and comprehensive molecular characterization for petroleum-derived releases. Here, we characterize more than 30 000 acidic, basic, and nonpolar unique neutral elemental compositions for the Macondo well crude oil, to provide an archive for future chemical analyses of the environmental consequences of the oil spill.

Characterization

Deepwater Horizon

10.1021/es305284t

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Citations (160)

Characterizations and comparison of low sulfur fuel oils compliant with 2020 global sulfur cap regulation for international shipping

Marine Pollution Bulletin (2022)

Robert K. Nelson Alan G. Scarlett Marthe Monique Gagnon Alex I. Holman Christopher M. Reddy

The International Marine Organization 2020 Global Sulfur Cap requires ships to burn fuels with <0.50% S and some countries require <0.10% S in certain Sulfur Emission Control Areas but little is known about these new types of fuels. Using both traditional GC-MS and more advanced chromatographic and mass spectrometry techniques, plus stable isotopic, δ13C and δ2H, analyses of pristane, phytane and n-alkanes, the organic components of a suite of three 0.50% S and three 0.10% S compliant fuels were characterized. Two oils were found to be near identical but all of the remaining oils could be forensically distinguished by comparison of their molecular biomarkers and by the profiles of the heterocyclic parent and alkylated homologues. Oils could also be differentiated by their δ13C and δ2H of n-alkanes and isoprenoids. This study provides important forensic data that may prove invaluable in the event of future oil spills.

Phytane

Fuel oil

10.1016/j.marpolbul.2022.113791

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Citations (12)