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Per- and polyfluoroalkyl substances (PFAS) are incorporated into an ever-increasing number of modern products and inevitably enter the environment and ultimately human bodies. Herein, we show that chemical ionization mass spectrometry with iodide reagent ion chemistry is a useful technique for the detection of fluorotelomer alcohols (FTOHs) and other oxygenated PFAS, including per- and polyfluoro carboxylic acids such as hexafluoropropylene oxide dimer acid. This technique offers direct, high-time resolution measurement capability with parts per trillion by volume (nanograms per cubic meter) gas-phase detection limits. Measurements were taken by direct volatilization of samples without prior processing, allowing for fast measurements and reduced sample treatment compared to established PFAS methods. We demonstrate the utility of this technique by sampling volatile and semivolatile PFAS from fluoro additives and fluoro products to quantify levels of FTOHs and identify additional fluorinated compounds for which standards were unavailable.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6550326 | PMC |
http://dx.doi.org/10.1021/acs.estlett.9b00196 | DOI Listing |
ACS Earth Space Chem
December 2024
NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, United States.
Laboratory investigations of photochemical reactions in simulated Titan-like atmospheric systems provide insight into the formation of gas and aerosol products and the influence of different environmental parameters on the types of organic molecules generated. Studying the gas-phase products as a function of reaction time provides further insight into the reaction pathways that lead to organic production. The stable isotopes in the reactants and products serve as tracers and help to disentangle these reaction pathways.
View Article and Find Full Text PDFEnviron Sci Process Impacts
December 2024
Department of Chemistry, University of Toronto, Canada.
Proton transfer reaction mass spectrometry (PTR-MS) is often employed to characterize gas-phase compounds in both indoor and outdoor environments. PTR-MS measurements are usually made without upstream chromatographic separation, so it can be challenging to differentiate between an ion of interest, its isomers, and fragmentation products from other species all detected at the same mass-to-charge ratio. These isomeric contributions and fragmentation interferences can confound the determination of accurate compound mixing ratios, the assignment of accurate chemical properties, and corresponding analyses of chemical fate.
View Article and Find Full Text PDFAcc Chem Res
December 2024
Department of Chemical and Petroleum Engineering, University of Kansas, Lawrence, Kansas 66045, United States.
ConspectusThe surface of a catalyst is crucial for understanding the mechanisms of catalytic reactions at the molecular level and developing new catalysts with higher activity, selectivity, and durability. Ambient pressure X-ray photoelectron spectroscopy (AP-XPS) is a technique studying the surface of a sample in the gas phase, mainly identifying chemical identity, analyzing oxidation state, and measuring surface composition.In the last decade, numerous photoelectron spectroscopic methods for fundamental studies of key topics in catalysis using AP-XPS have been developed.
View Article and Find Full Text PDFACS Omega
December 2024
Department of Physics, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara, Gujarat 39002, India.
Spurred by the latest developments and growing utilization of zero-dimensional (0D) drug delivery and drug sensors, this investigation examines the possibilities of the 0D C fullerene for drug delivery and the detection of the anticancer drug chlormethine (CHL), the overabundance of which poses a significant threat to living organisms. This study employs density functional theory and ab initio molecular dynamics (AIMD) simulations (AIMD) to evaluate and gain insights into the interaction mechanisms between pristine C fullerene, metal-metalloid (MM)-modified C fullerene (with Al, Fe, and B), and the anticancer drug CHL. It is observed that in the gas phase, the CHL drug molecule adsorbs onto the fullerenes in the following order: B-C > Fe-C > Al-C > C.
View Article and Find Full Text PDFLC-ESI-MS/MS is a preferred method for detecting and identifying metabolites, including those that are unpredictable from the genome, especially in basal metazoans like Cnidaria, which diverged earlier than bilaterians and whose metabolism is poorly understood. However, the unexpected appearance of a "ghost peak" for dopamine, which exhibited the same m/z value and MS/MS product ion spectrum during an analysis of Nematostella vectensis, a model cnidarian, complicated its accurate identification. Understanding the mechanism by which "ghost peaks" appear is crucial to accurately identify the monoamine repertoire in early animals so as to avoid misassignments.
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