High-Resolution Mass Spectrometric Profiling of Stormwater in an Australian Creek

Urban stormwater runoff is a major source of pollutants into receiving water bodies. The pollutant profile of stormwater samples collected from an Australian creek during a major storm event in 2020 was investigated using high-resolution mass spectrometry and chemometric tools. The samples were solid phase-extracted and analyzed by liquid chromatography coupled to a quadrupole time-of-flight mass spectrometer (LC-QToF-MS/MS). The detected features were prioritized using two independent but complementary workflows to identify the highly abundant stormwater-related compounds. A total of 174 features were detected at elevated levels during the storm. Four compounds were identified to a confidence level of 1 and 11 at level 2, including nonpolymeric surfactants, plastic additives, rubber and resin-related products, and natural products. Forty two percent were characterized as oligomers such as poly­(ethylene glycol) (PEG)-related compounds and octylphenol ethoxylates. Due to a lack of database experimental data, many compounds remained unidentified. Compounds belonging to the same class were clustered using Global Natural Product Social (GNPS) Molecular Networking analysis, highlighting the benefit of this platform in environmental analysis. The prioritization workflow used here is characterized as an effective tool for assessing key stormwater-related compounds and identifying which should receive attention in assessing the environmental effects of stormwater-related chemicals

Trichodermides A–E: New Peptaibols Isolated from the Australian Termite Nest-Derived Fungus <i>Trichoderma virens</i> CMB-TN16

Chemical analysis of a fermentation of the Australian termite nest-derived fungus <i>Trichoderma virens</i> CMB-TN16 yielded five new acyclic nonapeptides, trichodermides A–E (<b>1</b>–<b>5</b>). Amino acid residues, configurations, and sequences were determined by a combination of spectroscopic (NMR and MS-MS) and chemical (C₃ Marfey’s) methods. The trichodermides adhere to the sequence homology pattern common to <i>Trichoderma</i> 11 amino acid residue peptaibols; however, unlike other peptaibols the trichodermides do not exhibit antibacterial or antifungal activity and exhibit low to no cytotoxicity against mammalian cells. This variability in biological activity highlights the importance of knowing both planar structures and absolute configurations when interpreting structure–activity relationships

Spongian-16-one Diterpenes and Their Anatomical Distribution in the Australian Nudibranch <i>Goniobranchus collingwoodi</i>

Six new (<b>1</b>–<b>6</b>) spongian-16-one analogues have been characterized from the Australian nudibranch species <i>Goniobranchus collingwoodi</i>, along with four known spongian-16-one derivatives. The structures and relative configuration were suggested by spectroscopic analyses informed by molecular modeling. Dissection of animal tissue revealed that the mantle and viscera differ in their terpene composition. Whole body extracts were not toxic to brine shrimp (<i>Artemia</i> sp.), but were unpalatable to palaemon shrimp (<i>Palaemon serenus</i>) at a concentration found within the nudibranch. Individual terpenes were not cytotoxic to human lung (NCIH-460), colorectal (SW620), and liver (HepG2) cancer cells

Divirensols: Sesquiterpene Dimers from the Australian Termite Nest-Derived Fungus <i>Trichoderma virens</i> CMB-TN16

A chemical investigation of the Australian termite nest-derived fungus Trichoderma virens CMB-TN16 yielded the known sesquiterpene gliocladic acid (1), together with two new acetylated analogues, 3-acetylgliocladic acid (2) and 14-acetylgliocladic acid (3), and seven new dimeric congeners, divirensols A–G (4–10). All metabolites were identified by detailed spectroscopic analysis, supported by biosynthetic considerations, and were assessed for antibacterial and cytotoxic properties. The divirensols are examples of an exceptionally rare class of dimeric sesquiterpene, likely linked via a highly convergent biosynthetic pathway. HPLC-DAD-MS analysis of the crude fungal extract detected ions attributed to putative monomeric biosynthetic precursors

New PFASs Identified in AFFF Impacted Groundwater by Passive Sampling and Nontarget Analysis

Monitoring contamination from per- and polyfluoroalkyl substances (PFASs) in water systems impacted by aqueous film-forming foams (AFFFs) typically addresses a few known PFAS groups. Given the diversity of PFASs present in AFFFs, current analytical approaches do not comprehensively address the range of PFASs present in these systems. A suspect-screening and nontarget analysis (NTA) approach was developed and applied to identify novel PFASs in groundwater samples contaminated from historic AFFF use. A total of 88 PFASs were identified in both passive samplers and grab samples, and these were dominated by sulfonate derivatives and sulfonamide-derived precursors. Several ultrashort-chain (USC) PFASs (≤C3) were detected, 11 reported for the first time in Australian groundwater. Several transformation products were identified, including perfluoroalkane sulfonamides (FASAs) and perfluoroalkane sulfinates (PFASis). Two new PFASs were reported (((perfluorohexyl)sulfonyl)sulfamic acid; m/z 477.9068 and (E)-1,1,2,2,3,3,4,5,6,7,8,8,8-tridecafluorooct-6-ene-1-sulfonic acid; m/z 424.9482). This study highlights that several PFASs are overlooked using standard target analysis, and therefore, the potential risk from all PFASs present is likely to be underestimated

Novel Per- and Polyfluoroalkyl Substances Discovered in Cattle Exposed to AFFF-Impacted Groundwater

The leaching of per- and polyfluoroalkyl substances (PFASs) from Australian firefighting training grounds has resulted in extensive contamination of groundwater and nearby farmlands. Humans, farm animals, and wildlife in these areas may have been exposed to complex mixtures of PFASs from aqueous film-forming foams (AFFFs). This study aimed to identify PFAS classes in pooled whole blood (n = 4) and serum (n = 4) from cattle exposed to AFFF-impacted groundwater and potentially discover new PFASs in blood. Thirty PFASs were identified at various levels of confidence (levels 1a–5a), including three novel compounds: (i) perfluorohexanesulfonamido 2-hydroxypropanoic acid (FHxSA-HOPrA), (ii) methyl((perfluorohexyl)sulfonyl)sulfuramidous acid, and (iii) methyl((perfluorooctyl)sulfonyl)sulfuramidous acid, belonging to two different classes. Biotransformation intermediate, perfluorohexanesulfonamido propanoic acid (FHxSA-PrA), hitherto unreported in biological samples, was detected in both whole blood and serum. Furthermore, perfluoroalkyl sulfonamides, including perfluoropropane sulfonamide (FPrSA), perfluorobutane sulfonamide (FBSA), and perfluorohexane sulfonamide (FHxSA) were predominantly detected in whole blood, suggesting that these accumulate in the cell fraction of blood. The suspect screening revealed several fluoroalkyl chain-substituted PFAS. The results suggest that targeting only the major PFASs in the plasma or serum of AFFF-exposed mammals likely underestimates the toxicological risks associated with exposure. Future studies of AFFF-exposed populations should include whole-blood analysis with high-resolution mass spectrometry to understand the true extent of PFAS exposure

Communicating Confidence of Per- and Polyfluoroalkyl Substance Identification via High-Resolution Mass Spectrometry

Per- and polyfluoroalkyl substances (PFASs) are important environmental contaminants, yet relatively few analytical reference standards exist for this class. Nontarget analyses performed by means of high-resolution mass spectrometry (HRMS) are increasingly common for the discovery and identification of PFASs in environmental and biological samples. The certainty of PFAS identifications made via HRMS must be communicated through a reliable and harmonized approach. Here, we present a confidence scale along with identification criteria specific to suspect or nontarget analysis of PFASs by means of nontarget HRMS. Confidence levels range from level 1a“Confirmed by Reference Standard,” and level 1b“Indistinguishable from Reference Standard,” to level 5“Exact Masses of Interest,” which are identified by suspect screening or data filtering, two common forms of feature prioritization. This confidence scale is consistent with general criteria for communicating confidence in the identification of small organic molecules by HRMS (e.g., through a match to analytical reference standards, library MS/MS, and/or retention times) but incorporates the specific conventions and tools used in PFAS classification and analysis (e.g., detection of homologous series and specific ranges of mass defects). Our scale clarifies the level of certainty in PFAS identification and, in doing so, facilitates more efficient identification