ACS Earth and Space Chemistry最新文献

{"title":"Surfactant Effects in Irradiated, Hanging-Droplet, Aqueous-Phase Glyoxal/Ammonium Sulfate Aerosol Mimic Systems","authors":"Daphna Fertil,&nbsp;Katherine Pierre-Louis,&nbsp;Stephanie Ingwer,&nbsp;Melissa M. Galloway and Joseph L. Woo*,&nbsp;","doi":"10.1021/acsearthspacechem.4c0028810.1021/acsearthspacechem.4c00288","DOIUrl":"https://doi.org/10.1021/acsearthspacechem.4c00288https://doi.org/10.1021/acsearthspacechem.4c00288","url":null,"abstract":"<p >Carbonyl-containing volatile organic compounds (CVOCs) are present in a wide range of atmospherically relevant contexts and can contribute significant portions of water-soluble organic carbon in aqueous aerosols, forming a variety of heterocyclic or oligomeric products under dark conditions. However, condensed-phase chemistry under irradiated conditions is much less understood and results in potential shifts to the overall extent of CVOC oligomerization. This study reports in situ surface tension measurements of glyoxal/ammonium sulfate hanging-droplet aqueous aerosol mimics that are directly irradiated with ultraviolet light and subsequently undergo aqueous-phase photochemistry due to this exposure. The surface tension values of aged glyoxal/ammonium sulfate solutions (79.7 ± 0.2 dyn/cm) are slightly lower than those of ammonium sulfate solutions without organics (80.1 ± 0.2 dyn/cm). Direct photochemistry in hanging droplets results in the formation of products capable of slight (−2.9 ± 2.3%) but statistically significant (<i>p</i> = 0.002) surface tension depression. Changes in the relative quantities of heterocyclic and aldol oligomeric products are observed in irradiated, hanging-droplet aerosol mimics, in contrast to comparably irradiated bulk solutions and non-irradiated hanging-droplet samples. Mimic solutions containing additional surfactants [sodium dodecyl sulfate (SDS) and methylsuccinic acid (MSA)] also exhibit compositional changes but do not demonstrate statistically significant differences in surface tension upon being irradiated (<i>p</i> = 0.563 and 0.422 for SDS and MSA, respectively).</p>","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":"9 3","pages":"524–532 524–532"},"PeriodicalIF":2.9,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143654365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Light-Driven Abiotic Formation of Dimethyl Selenyl Sulfide in the Liquid and Gas Phases","authors":"Paul A. Heine,&nbsp;Phuoc Sanh Nguyen and Nadine Borduas-Dedekind*,&nbsp;","doi":"10.1021/acsearthspacechem.4c0035410.1021/acsearthspacechem.4c00354","DOIUrl":"https://doi.org/10.1021/acsearthspacechem.4c00354https://doi.org/10.1021/acsearthspacechem.4c00354","url":null,"abstract":"<p >Biogenically produced volatile organic selenium (Se) species such as dimethyl selenyl sulfide (CH₃SeSCH₃) and dimethyl diselenide (CH₃SeSeCH₃) are important sources of Se in the atmosphere. Once emitted, Se can travel through the atmosphere and subsequently deposit to soils, impacting available Se in food crops. To improve the predictive capabilities of the sources and sinks of CH₃SeSCH₃, we studied its abiotic light-driven formation and subsequent photochemical decay. Upon UVA irradiation of CH₃SeSeCH₃ and its more abundant sulfur analogue, dimethyl disulfide (CH₃SSCH₃), we observed the formation of CH₃SeSCH₃ in both the liquid and gas phases. We unambiguously confirmed the synthesis of CH₃SeSCH₃ by GC-MS and ¹H, ¹³C, and ⁷⁷Se NMR spectroscopy before studying this process by online Vocus mass spectrometry in the gas phase. The photolysis by UVA light produced selenyl and thiyl radicals, which formed CH₃SeSCH₃ in 36% yield. Moreover, we identified photo-oxidation products and subsequent SOA formation. Our mechanistic analysis concludes that the detection of CH₃SeSCH₃ in the environment coexists with CH₃SeSeCH₃ and CH₃SSCH₃. Thus, CH₃SeSCH₃ in the environment, for example, above a phytoplankton bloom, may have a combination of both primary and secondary sources. Our study shines light on CH₃SeSCH₃’s synthesis, isolation, and environmental transformations.</p>","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":"9 3","pages":"638–648 638–648"},"PeriodicalIF":2.9,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143654361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gas-Phase Nitrate Radical Production Using Irradiated Ceric Ammonium Nitrate: Insights into Secondary Organic Aerosol Formation from Biogenic and Biomass Burning Precursors","authors":"Andrew T. Lambe*,&nbsp;Chase K. Glenn,&nbsp;Anita M. Avery,&nbsp;Tianchang Xu,&nbsp;Jenna C. Ditto,&nbsp;Manjula R. Canagaratna,&nbsp;Drew R. Gentner,&nbsp;Kenneth S. Docherty,&nbsp;Mohammed Jaoui,&nbsp;Julia Zaks,&nbsp;Allan K. Bertram,&nbsp;Nga L. Ng and Pengfei Liu,&nbsp;","doi":"10.1021/acsearthspacechem.4c0029310.1021/acsearthspacechem.4c00293","DOIUrl":"https://doi.org/10.1021/acsearthspacechem.4c00293https://doi.org/10.1021/acsearthspacechem.4c00293","url":null,"abstract":"<p >The importance of nitrate radicals (NO₃) as an atmospheric oxidant is well-established. For decades, laboratory studies of multiphase NO₃ chemistry have used the same methods – either NO₂ + O₃ reactions or N₂O₅ thermal decomposition – to generate NO₃ as it occurs in the atmosphere. These methods, however, come with limitations, especially for N₂O₅, which must be produced and stored under cold and dry conditions until its use. Recently, we developed a new photolytic source of gas-phase NO₃ by irradiating aqueous solutions of ceric ammonium nitrate and nitric acid. In this study, we adapted the method to maintain stable NO₃ concentrations for over 24 h. We applied the method in laboratory oxidation flow reactor (OFR) experiments to measure the yield and chemical composition of oxygenated volatile organic compounds (OVOCs) and secondary organic aerosol (SOA) formed from NO₃ oxidation of volatile organic compounds (VOCs) emitted by biogenic sources (isoprene, β-pinene, limonene, and β-caryophyllene) and biomass burning sources (phenol, guaiacol, and syringol). SOA yields and elemental ratios were typically within a factor of 2 and 10%, respectively, of those obtained in studies using conventional NO₃ sources. Maximum SOA yields obtained in our studies ranged from 0.02 (isoprene/NO₃) to 0.96 (β-caryophyllene/NO₃). The highest SOA oxygen-to-carbon ratios (O/C) ranged from 0.48 (β-caryophyllene/NO₃) to 1.61 (syringol/NO₃). Additionally, we characterized novel condensed-phase oxidation products from syringol/NO₃ reactions. Overall, the use of irradiated aqueous cerium nitrate as a source of gas-phase NO₃ may enable more widespread studies of NO₃-initiated oxidative aging, which has been less explored compared to that of hydroxyl radical chemistry.</p>","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":"9 3","pages":"545–559 545–559"},"PeriodicalIF":2.9,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143654360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ionic Strength Effect in Fenton Reactions in the Presence of Sulfate and Its Influence on the Aqueous Particle Phase","authors":"Daniele Scheres Firak,&nbsp;Thomas Schaefer,&nbsp;Celine Kula,&nbsp;Nazanin Taherkhani and Hartmut Herrmann*,&nbsp;","doi":"10.1021/acsearthspacechem.4c0036210.1021/acsearthspacechem.4c00362","DOIUrl":"https://doi.org/10.1021/acsearthspacechem.4c00362https://doi.org/10.1021/acsearthspacechem.4c00362","url":null,"abstract":"<p >Fenton chemistry [Fe(II) + H₂O₂] is a critical source of hydroxyl radicals (^•OH) in deliquescent aerosols, yet its efficiency is significantly modulated by the high ionic strength (<i>I</i>) of these systems. This study investigates the influence of elevated sulfate concentrations on Fenton reactions under aerosol-relevant conditions. The isolated effect of ionic strength was first studied by using NaClO₄ as a model electrolyte. Results reveal that the Fenton reaction rate constant decreases sharply to 16 ± 1 M^–1 s^–1 until <i>I</i> = 2 M, increasing at higher <i>I</i> values. Fe(II) oxidation by dissolved O₂ increased to 282 ± 46 M^–1 s^–1 at <i>I</i> = 8 M, although dissolved O₂ concentrations are expected to decrease due to salting-out effects on oxygen. In Na₂SO₄ solutions, Fe speciation shifts to FeSO₄, resulting in enhanced rate constants, reaching 239 ± 21 M^–1 s^–1 at <i>I</i> = 2.7 M. Interestingly, Fe(II) oxidation by O₂ is negligible in Na₂SO₄ solutions. The final OH yield remained unchanged in FeSO₄ solutions and decreased markedly in NaClO₄ solutions. Arrhenius expressions were derived for the Fenton reaction in 3.6 M NaClO₄ <i>k</i>(<i>T</i>) = (8.7 ± 0.8) × 10⁷ × exp[(−4276 ± 520 K)/<i>T</i>] and the reaction in the presence of 1.2 M Na₂SO₄, <i>k</i>(<i>T</i>) = (7.5 ± 0.2) × 10⁹ × exp[(−5153 ± 310 K)/<i>T</i>]. Despite the suppressive effects of <i>I</i> on radical generation, the formation of FeSO₄ enhances the relevance of Fenton chemistry, highlighting its amplified role in sulfate-rich aerosol environments.</p>","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":"9 3","pages":"662–670 662–670"},"PeriodicalIF":2.9,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsearthspacechem.4c00362","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143654363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chemical Characterization of Organosulfur Compounds in Aerosols from Archean-Analog Photochemistry: Insights from Liquid Chromatography and High-Resolution Tandem Mass Spectrometry","authors":"Cade M. Christensen,&nbsp;Nathan W. Reed,&nbsp;Boswell A. Wing,&nbsp;Shawn E. McGlynn,&nbsp;Margaret A. Tolbert,&nbsp;Eleanor C. Browne* and Jason D. Surratt*,&nbsp;","doi":"10.1021/acsearthspacechem.4c0031410.1021/acsearthspacechem.4c00314","DOIUrl":"https://doi.org/10.1021/acsearthspacechem.4c00314https://doi.org/10.1021/acsearthspacechem.4c00314","url":null,"abstract":"<p >Fine aerosols are critical in influencing planetary climate and surface conditions, and thus, understanding the sources and chemical composition of aerosols is vital for constraining the habitability potential of a planet. Molecular nitrogen (N₂), methane (CH₄), carbon dioxide (CO₂), and sulfur gases (e.g., hydrogen sulfide (H₂S) and sulfur dioxide (SO₂)) are common components of planetary atmospheres that can undergo atmospheric photochemical reactions to produce both inorganic and organic aerosols. Recent studies have shown that organic aerosol production is closely tied to the presence of H₂S, potentially through the formation of organosulfur compounds. However, molecular-level speciation of organosulfur compounds is lacking, thus limiting our understanding of what, if any, implications these compounds hold for the early beginnings of life or the planetary climate. Here, we chemically characterized 60 organosulfur compounds in aerosols produced during laboratory analog experiments using an irradiated mixture of 0.5% CO₂ with 0.1% CH₄ and 5 ppm of H₂S in a N₂ background by hydrophilic interaction liquid chromatography coupled to electrospray ionization high-resolution quadrupole time-of-flight mass spectrometry (HILIC/ESI-HR-QTOFMS). Accurate mass and tandem mass spectrometry measurements provided information regarding sulfur functionality and the overall chemical structure. Sulfur was found in multiple oxidation states within functional groups such as sulfates, sulfonic acids, sulfites, sulfinic acids, and thiols. We found that five simple organosulfur species, including methyl sulfate, ethyl sulfate, methanesulfonic acid, ethanesulfonic acid, and isethionic acid, contributed 6.2–7.9% of the total aerosol mass. These results suggest that organosulfur could have played a significant role in the Archean sulfur cycle.</p>","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":"9 3","pages":"569–588 569–588"},"PeriodicalIF":2.9,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143654362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Using Stable Sulfur Isotopes to Quantify the Formation Mechanism and Sources of SO42– in PM2.5 in Haikou City","authors":"Rongqiang Yang,&nbsp;Quansheng Lou*,&nbsp;Mingbin Wang,&nbsp;Lingling Cao and Li Luo*,&nbsp;","doi":"10.1021/acsearthspacechem.4c0030410.1021/acsearthspacechem.4c00304","DOIUrl":"https://doi.org/10.1021/acsearthspacechem.4c00304https://doi.org/10.1021/acsearthspacechem.4c00304","url":null,"abstract":"<p >As an important component of fine atmospheric particles (PM_2.5), sulfate (SO₄^2–) mediates the physicochemical characteristics of PM_2.5. The δ³⁴S–SO₄^2– values and water-soluble inorganic ion concentrations in PM_2.5 were analyzed in Haikou City, Hainan Province, China, from September 2021 to August 2022. SO₄^2– was found to be the most abundant ion in PM_2.5, accounting for 39.0%–58.7% of all water-soluble inorganic ions. The δ³⁴S–SO₄^2– values in PM_2.5 ranged from −0.9 to 10.0‰, with low values recorded in autumn (2.3‰ ± 2.3‰) and winter (2.2‰ ± 1.9‰), but higher values were observed in spring (6.4‰ ± 1.9‰) and summer (6.2‰ ± 1.1‰). The calculated total fractionation factors (ε_total) between gas-phase SO₂ and PM_2.5 SO₄^2– were −0.4‰ ± 1.8‰, −0.2‰ ± 1.6‰, 2.9‰ ± 1.4‰, and 3.3‰ ± 1.1‰ in autumn, winter, spring, and summer, respectively. Based on the ³⁴S fractionation factors, we found that the SO₂ + O₂(TMI) pathway contributes the highest percentages of secondary SO₄^2– formation in autumn (34.3% ± 6.3%) and winter (38.5% ± 4.8%), while photochemical-derived formation pathways (SO₂ + H₂O₂/O₃ and SO₂ + OH) dominated secondary SO₄^2– formation in summer (48.2% ± 2.5%). The estimated source contributions to SO₄^2– in PM_2.5 indicated that ship emissions contributed the highest percentage (48.8% ± 12.0%) in PM_2.5 in Haikou City. The findings of this study indicate that reducing the ship exhaust over the northern South China Sea would be beneficial for mitigating SO₄^2– pollution for the Hainan Free Trade Port.</p>","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":"9 3","pages":"560–568 560–568"},"PeriodicalIF":2.9,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143654357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Experimental Rate Constant of the S+(2D) + H2 Reaction","authors":"Alexandre Zanchet*,&nbsp;Jia Lei Chen-Qiu,&nbsp;Pascal Larregaray,&nbsp;Laurent Bonnet,&nbsp;Claire Romanzin,&nbsp;Nicolas Solem,&nbsp;Roland Thissen and Christian Alcaraz,&nbsp;","doi":"10.1021/acsearthspacechem.4c0039110.1021/acsearthspacechem.4c00391","DOIUrl":"https://doi.org/10.1021/acsearthspacechem.4c00391https://doi.org/10.1021/acsearthspacechem.4c00391","url":null,"abstract":"<p >Endothermic reactions such as <i>S</i>⁺(⁴<i>S</i>) + <i>H</i>₂ are not expected to play a significant role in the chemistry of the interstellar medium (ISM). However, in some specific environments, such as photon-dominated regions (PDR), UV radiation may catalyze the reaction by providing enough internal energy to reactants to overcome endothermicity. For instance, it was recently shown that the vibrational excitation of H₂ greatly enhances the reactivity of C⁺ and S⁺ with H₂, explaining the presence of their respective hydrides CH⁺ and SH⁺ in these regions. However, vibrational excitation of H₂ is not a unique way to enhance the reactivity by UV radiation. Electronic excitation is an alternative way to effectively inject a huge amount of internal energy into the system, thus favoring reactivity. In this work, we will address how electronic excitation of the sulfur cation can strongly enhance the production of SH⁺. This is done by measuring experimentally the cross section of the title reaction for collision energies from 50 meV up to several eV and comparing the results with theoretical predictions in the 0.001–3 eV range. The reaction cross section is then used to derive the rate constant for a wide range of temperatures.</p>","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":"9 3","pages":"738–745 738–745"},"PeriodicalIF":2.9,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsearthspacechem.4c00391","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143654336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Experimental Rate Constant of the <i>S</i> ⁺(² <i>D</i>) + <i>H</i> ₂ Reaction.","authors":"Alexandre Zanchet, Jia Lei Chen-Qiu, Pascal Larregaray, Laurent Bonnet, Claire Romanzin, Nicolas Solem, Roland Thissen, Christian Alcaraz","doi":"10.1021/acsearthspacechem.4c00391","DOIUrl":"10.1021/acsearthspacechem.4c00391","url":null,"abstract":"<p><p>Endothermic reactions such as <i>S</i> ⁺(⁴ <i>S</i>) + <i>H</i> ₂ are not expected to play a significant role in the chemistry of the interstellar medium (ISM). However, in some specific environments, such as photon-dominated regions (PDR), UV radiation may catalyze the reaction by providing enough internal energy to reactants to overcome endothermicity. For instance, it was recently shown that the vibrational excitation of H₂ greatly enhances the reactivity of C⁺ and S⁺ with H₂, explaining the presence of their respective hydrides CH⁺ and SH⁺ in these regions. However, vibrational excitation of H₂ is not a unique way to enhance the reactivity by UV radiation. Electronic excitation is an alternative way to effectively inject a huge amount of internal energy into the system, thus favoring reactivity. In this work, we will address how electronic excitation of the sulfur cation can strongly enhance the production of SH⁺. This is done by measuring experimentally the cross section of the title reaction for collision energies from 50 meV up to several eV and comparing the results with theoretical predictions in the 0.001-3 eV range. The reaction cross section is then used to derive the rate constant for a wide range of temperatures.</p>","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":"9 3","pages":"738-745"},"PeriodicalIF":2.9,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11931544/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143707775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of Phase Conditions of CO2-Rich Fluids Measured at Different Hydrothermal Fields in the Okinawa Trough Using an In Situ Deep-Sea Raman Spectrometer","authors":"Tomoko Takahashi*,&nbsp;Eiji Tasumi,&nbsp;Shotaro Tagawa,&nbsp;Yatsuse Majima,&nbsp;Junichi Miyazaki,&nbsp;Naoki Nishimura,&nbsp;Shinsuke Kawagucci,&nbsp;Takazo Shibuya and Ken Takai,&nbsp;","doi":"10.1021/acsearthspacechem.4c0024610.1021/acsearthspacechem.4c00246","DOIUrl":"https://doi.org/10.1021/acsearthspacechem.4c00246https://doi.org/10.1021/acsearthspacechem.4c00246","url":null,"abstract":"<p >In this work, in situ liquid carbon dioxide (CO₂)-rich fluid measurements using a deep-sea Raman spectrometer at different hydrothermal fields in the Okinawa Trough were performed. It was found that the water depths where the CO₂ phase turned from liquid to gas ranged from 710 to 1060 m, which were deeper than the depth indicated in the phase diagram of the mixture of water (H₂O) and CO₂ (∼415 m), while our previous observation at the North-West Eifuku site at the Mariana Arc was consistent with the diagram. From observations with in situ Raman measurements and gas chromatography (GC) quantitative analysis of collected fluid samples, it can be assumed that the depth of the phase transition depends predominantly on the concentration of methane (CH₄) and nitrogen (N₂) in the fluid. The study demonstrates the ability of the Raman spectroscopic technique to be used as a real-time, on-site sensing tool for monitoring the dynamic phase transitions of CO₂ and volatiles in fluids in the oceans. In addition, the apparatus reported in this work makes it possible to conduct multimodal liquid CO₂-rich-fluid analysis by performing in situ continuous Raman measurements, GC analysis of the sampled fluid, and visual observation. This will lead to a better understanding of the role of CO₂-rich fluids emitted from deep-sea hydrothermal fields in biogeochemical cycles and their contribution to acidification in the water column.</p>","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":"9 3","pages":"467–479 467–479"},"PeriodicalIF":2.9,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143654324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CN– and C3N– Reactivity with Formic and Acetic Acid, Acetaldehyde, and Methanol","authors":"Nicolas Solem,&nbsp;Claire Romanzin and Roland Thissen*,&nbsp;","doi":"10.1021/acsearthspacechem.4c0039610.1021/acsearthspacechem.4c00396","DOIUrl":"https://doi.org/10.1021/acsearthspacechem.4c00396https://doi.org/10.1021/acsearthspacechem.4c00396","url":null,"abstract":"<p >The anion-molecule reactivity of CN^– and C₃N^–, produced by dissociative electron attachment of the respective bromide precursors, with four oxygenated molecules has been investigated in a guided ion beam mass spectrometer, and absolute reaction cross-sections are derived as a function of collision energy. The four targets are formic acid, acetic acid, acetaldehyde, and methanol. Exothermic and endothermic proton transfer has been observed as the main reaction channel, with differences in cross-section between the two anions. Oxidation of the anions is also observed, forming OCN^– and OC₃N^–, for both anions and limited to the targets with endothermic proton transfer for CN^–. This reaction requires several rearrangements and, therefore, a long-lived complex to proceed. Other complex-mediated products are observed for C₃N^– but not for CN^–, interpreted as the ability to proceed through a long-lived complex because of less easy proton transfer for C₃N^–. Comparison between the present results at low-collision energy, models, and previous studies are producing a coherent picture. Several products observed with C₃N^– were missing formation enthalpies. Using the experimental exothermic behavior, it was possible to determine the upper limit values for enthalpies for the formation of OC₃N^– (0.39 ± 0.25 eV), [H₂OC₃N]⁻ (0.39 ± 0.25 eV), C₄N^– (0.65 ± 0.25 eV), and CH₃C₃N^– (3.52 ± 0.25 eV).</p>","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":"9 3","pages":"757–768 757–768"},"PeriodicalIF":2.9,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143654320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}