About

David Alfred Hoffman is the Steed Family Professor of the Practice of Public Policy and a Professor of the Practice in the Sanford School of Public Policy at Duke University. He serves as the Interim Director of the Duke Initiative for Science & Society and is an Associate of the Duke Initiative for Science & Society. Additionally, he is an Affiliate Faculty Member at the Duke-Margolis Institute for Health Policy. His work includes creating a three-part podcast series titled 'Defending Democracy (and Us!) From Big Tech,' which reflects his engagement with contemporary issues at the intersection of technology, democracy, and policy. His contact information is provided as david.hoffman@duke.edu, and he is based in the Sanford Building in Durham, North Carolina.

Research topics

• Chemistry
• Stereochemistry
• Chromatography
• Physics
• Materials science
• Nuclear physics
• Organic chemistry
• Nuclear magnetic resonance
• Computational chemistry
• Environmental chemistry
• Biology
• Biochemistry

Selected publications

• Opportunities and Limitations of Nuclear Magnetic Resonance Spectroscopy in Astrobiology

  ACS Earth and Space Chemistry · 2026-01-21

  articleSenior author

  For decades, nuclear magnetic resonance (NMR) spectroscopy has been utilized as a powerful tool in various scientific disciplines, most prominently in chemistry, to determine molecular structures or monitor reactions. While well established in various fields, NMR applications in astrobiology are still unclear. This work aims to explore the potential of NMR in astrobiology, highlighting strengths but also weaknesses. We illustrate the capabilities of NMR with two applications: (1) recently developed methods for position-specific carbon isotope analysis of complex organics; and (2) well-established tools for performing quantitative compositional analysis of complex organic mixtures. By utilizing samples relevant to astrobiology, specifically the amino acid valine and analogue mixtures of organics, we showcase that molecules retain a source-dependent and distinct intramolecular carbon isotope fingerprint. We demonstrate that compositional sample analysis provides an independent and complementary line of evidence pointing toward the origin of a molecule or mixture. Together, these NMR tools have the potential to support life detection efforts and aid in distinguishing between biotic and abiotic samples. Finally, we discuss sensitivity, detection limits, and the portability of NMR, and propose how integration with mass-spectrometry techniques will be imperative to enable more targeted and comprehensive analyses relevant to astrobiology, including in situ analysis, but also sample return missions.

  PublisherDOI

• Injection Capacity of Shallow Reservoirs in the Permian Basin: Implications for Wastewater Management in the World’s Most Productive Oilfield

  Abstracts with programs - Geological Society of America · 2025-01-01

  article
  PublisherDOI

• Nature's first electrical tool: microbial biofilms using electron transfer networks to perform aerobic respiration in an anaerobic environment

  Bioelectrochemistry · 2025-08-07

  article
  PublisherDOI

• Integrated Seismic and Outcrop Characterization of Pore Space for Wastewater Injection in the Delaware Mountain Group, Delaware Basin

  Abstracts with programs - Geological Society of America · 2025-01-01

  article
  PublisherDOI

• Permian Delaware Basin Productivity and Spacing Analysis and Technically Recoverable Resource Assessment

  2025-01-01

  articleSenior author
  PublisherDOI

• Position-specific carbon stable isotope analysis of glyphosate: isotope fingerprinting of molecules within a mixture

  Analytical and Bioanalytical Chemistry · 2024-05-14 · 4 citations

  article1st authorCorresponding
  PublisherDOI

• Fingerprinting Organofluorine Molecules via Position-Specific Isotope Analysis

  Environmental Science & Technology · 2024-07-18 · 4 citations

  articleSenior author

  Organofluorine substances are found in a wide range of materials and solvents commonly used in industry and homes, as well as pharmaceuticals and pesticides. In the environment, organofluorine molecules are now recognized as an important class of anthropogenic pollutants. Fingerprinting organofluorine compounds via their carbon isotope ratios (13C/12C) is crucial for correlating molecules with their source. Here we apply a 19F nuclear magnetic resonance spectroscopy (NMR) technique to obtain the first position-specific carbon isotope ratios for a diverse set of organofluorine molecules. In contrast to traditional isotope ratio mass spectrometry, the 19F NMR method provides 13C/12C isotope ratios at each carbon position where a C–F bond is present, and does not require fragmentation or combustion to CO2, overcoming challenges posed by the robust C–F covalent bonds. The method was validated with 2,2,2-trifluoroethanol, and applied to analyze heptafluorobutanoic acid, 5-fluorouracil and fipronil. Results reveal distinct intramolecular carbon isotope distributions, enabling differentiation of chemically identical molecules. Notably, the NMR method accurately analyzes carbon isotopes within target molecules despite impurities. Potential applications include the detection of counterfeit products and drugs, and ultimately pollution tracking in the environment.

  PublisherDOI

• Influence of Geological, Completion, and Well-Spacing Parameters on First-Year Productivity in the Delaware Basin

  2024-01-01

  article
  PublisherDOI

• A One‐Dimensional Volcanic Plume Model for Predicting Ash Aggregation

  Journal of Geophysical Research Solid Earth · 2023-07-26 · 4 citations

  articleOpen access1st author

  Abstract During explosive volcanic eruptions, volcanic ash is ejected into the atmosphere, impacting aircraft safety and downwind communities. These volcanic clouds tend to be dominated by fine ash (<63 μm in diameter), permitting transport over hundreds to thousands of kilometers. However, field observations show that much of this fine ash aggregates into clusters or pellets with faster settling velocities than individual particles. Models of ash transport and deposition require an understanding of aggregation processes, which depend on factors like moisture content and local particle collision rates. In this study, we develop a Plume Model for Aggregate Prediction, a one‐dimensional (1D) volcanic plume model that predicts the plume rise height, concentration of water phases, and size distribution of resulting ash aggregates from a set of eruption source parameters. The plume model uses a control volume approach to solve mass, momentum, and energy equations along the direction of the plume axis. The aggregation equation is solved using a fixed pivot technique and incorporates a sticking efficiency model developed from analog laboratory experiments of particle aggregation within a novel turbulence tower. When applied to the 2009 eruption of Redoubt Volcano, Alaska, the 1D model predicts that the majority of the plume is over‐saturated with water, leading to a high rate of aggregation. Although the mean grain size of the computed Redoubt aggregates is larger than the measured deposits, with a peak at 1 mm rather than 500 μm, the present results provide a quantitative estimate for the magnitude of aggregation in an eruption.

  PublisherOA PDFDOI

• Novel Nuclear Magnetic Resonance Method for Position-Specific Carbon Isotope Analysis of Organic Molecules with Significant Impurities

  Analytical Chemistry · 2022 · 10 citations

  Senior authorCorresponding
  • Chemistry
  • Nuclear magnetic resonance
  • Stereochemistry

  Cα isotope spikes in USGS74 and USGS75 were clearly detected, where they preserve carbon isotope ratios of -4.8 ± 0.9‰ and +11.5 ± 0.8‰, respectively. Carbon isotope abundance at the beta and gamma positions indicates that the USGS73 l-valine was obtained from a different source than USGS74 and -75. This analytical approach is a significant step forward in the field of position-specific isotope analysis at natural abundance via NMR because it enables the investigation of samples that contain impurities which are typically present in samples derived from natural sources.

  PublisherOA PDFDOI

Recent grants

• NIH Grant R01AI040187

  NIH · $2.4M · 2008

• NIH Grant K02AI001497

  NIH · $443k · 2003

Frequent coauthors

• Stephen W. White

  St. Jude Children's Research Hospital

  50 shared

• V. Ramakrishnan

  MRC Laboratory of Molecular Biology

  32 shared

• Christopher Stan Cameron

  Sanford Health

  26 shared

• Christopher Davies

  25 shared

• Peter Schmid

  19 shared

• Paul Shapshak

  Tampa General Hospital

  18 shared

• Maryam Darvish

  Arak University of Medical Sciences

  18 shared

• S. Nakamura

  University of Tsukuba

  17 shared