Formation of low molecular weight mono- and di-carboxylic acids and related compounds from photochemical oxidation of stearic and linoleic acids in aqueous-phase

2020 ◽  
Author(s):  
Chandra Mouli Pavuluri ◽  
Subba Rao Devineni ◽  
Zhanjie Xu ◽  
Kimitaka Kawamura ◽  
Pingqing Fu ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Aqueous Phase ◽  
Cloud Condensation Nuclei ◽  
Oxidation Products ◽  
Photochemical Oxidation ◽  
Air Water Interface ◽  
Volatile Organic ◽  
Product Species ◽  
Related Compounds ◽  
Atmospheric Waters

<p>Secondary organic aerosols (SOA) that account for a substantial and often a dominant fraction of total OA mass are formed by photooxidation of various precursors derived from anthropogenic and biogenic sources in the atmosphere. They have serious impacts on the Earth’s climate system directly by scattering and absorbing solar radiation and indirectly by acting as cloud condensation nuclei, and adverse effects on human health. In recent times, considerable attention has been paid on laboratory studies, preferably in gas-phase, in order to understand the chemistry of SOA formation. However, the studies on SOA formation in aqueous phase are limited, which are mainly focused on high abundant volatile organic compounds (e.g., isoprene) and/or their oxidation products, but not on fatty acids (except oleic acid). To better understand the air-water interface photochemistry of fatty acids and their transformations to lower homologous monoacids and more oxygenated species such as diacids and related compounds in atmospheric waters (fog, cloud and aqueous aerosol), we conducted batch UV irradiation experiments on a saturated (stearic acid, C<sub>18</sub>H<sub>36</sub>O<sub>2</sub>) and an unsaturated (linoleic acid, C<sub>18</sub>H<sub>32</sub>O<sub>2</sub>) fatty acids for different time periods (age, 0-120 h) in aqueous-phase. All the irradiated samples were analyzed for measurements of mono- and di-acids, oxoacids and α-dicarbonyls. We found high abundances of monoacids followed by diacids, pyruvic acid and α-dicarbonyls in less aged samples, whereas C<sub>3</sub> and C<sub>4</sub> diacids were abundant in the more aged samples. Our results imply that the photochemical oxidation of fatty acids and subsequent transformations of the product species in atmospheric waters are significant and their contribution to more oxygenated SOA is increased with aging in the atmosphere.</p>

scholarly journals Characterisation and optimisation of a method for the detection and quantification of atmospherically relevant carbonyl compounds in aqueous medium

2015 ◽  
Vol 8 (1) ◽  
pp. 857-876
Author(s):  
M. Rodigast ◽  
A. Mutzel ◽  
Y. Iinuma ◽  
S. Haferkorn ◽  
H. Herrmann
Keyword(s):  
Aqueous Phase ◽  
Carbonyl Compounds ◽  
Ph Value ◽  
Hydroxylamine Hydrochloride ◽  
Oxidation Products ◽  
Gas Chromatography Mass Spectrometry ◽  
Methyl Glyoxal ◽  
Comprehensive Description ◽  
Volatile Organic ◽  
Atmospherically Relevant

Abstract. Carbonyl compounds are ubiquitous in the atmosphere and either emitted primarily from anthropogenic and biogenic sources or they are produced secondarily from the oxidation of volatile organic compounds (VOC). Despite a number of studies about the quantification of carbonyl compounds a comprehensive description of optimised methods is scarce for the quantification of atmospherically relevant carbonyl compounds. Thus a method was systematically characterised and improved to quantify carbonyl compounds. Quantification with the present method can be carried out for each carbonyl compound sampled in the aqueous phase regardless of their source. The method optimisation was conducted for seven atmospherically relevant carbonyl compounds including acrolein, benzaldehyde, glyoxal, methyl glyoxal, methacrolein, methyl vinyl ketone and 2,3-butanedione. O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA) was used as derivatisation reagent and the formed oximes were detected by gas chromatography/mass spectrometry (GC/MS). The main advantage of the improved method presented in this study is the low detection limit in the range of 0.01 and 0.17 μmol L−1 depending on carbonyl compounds. Furthermore best results were found for extraction with dichloromethane for 30 min followed by derivatisation with PFBHA for 24 h with 0.43 mg mL−1 PFBHA at a pH value of 3. The optimised method was evaluated in the present study by the OH radical initiated oxidation of 3-methylbutanone in the aqueous phase. Methyl glyoxal and 2,3-butanedione were found to be oxidation products in the samples with a yield of 2% for methyl glyoxal and 14% for 2,3-butanedione.

scholarly journals Characterization of Products from the Aqueous-Phase Photochemical Oxidation of Benzene-Diols

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 534
Author(s):  
Yang Ou ◽  
Dongyang Nie ◽  
Hui Chen ◽  
Zhaolian Ye ◽  
Xinlei Ge
Keyword(s):  
Aqueous Phase ◽  
Irradiation Time ◽  
Chemical Properties ◽  
Oxidation Products ◽  
Photochemical Oxidation ◽  
Reaction Products ◽  
Reaction Conditions ◽  
Oxidative Potential ◽  
Photo Degradation

Chemical processing in atmospheric aqueous phases, including cloud and fog drops, might be significant in reconciling the gap between observed and modeled secondary organic aerosol (SOA) properties. In this work, we conducted a relatively comprehensive investigation of the reaction products generated from the aqueous-phase photochemical oxidation of three benzene-diols (resorcinol, hydroquinone, and methoxyhydroquinone) by hydroxyl radical (·OH), triplet excited state (3C*) 3,4-dimethoxybenzaldehyde (3,4-DMB), and direct photolysis without any added oxidants. The results show that OH-initiated photo-degradation is the fastest of all the reaction systems. For the optical properties, the aqueous oxidation products generated under different reaction conditions all exhibited photo-enhancement upon illumination by simulated sunlight, and the light absorption was wavelength dependent on and increased as a function of the reaction time. The oxygen-to-carbon (O/C) ratio of the products also gradually increased against the irradiation time, indicating the persistent formation of highly oxygenated low-volatility products throughout the aging process. More importantly, aqueous-phase products from photochemical oxidation had an increased oxidative potential (OP) compared with its precursor, indicating they may more adversely impact health. The findings in this work highlight the importance of aqueous-phase photochemical oxidation, with implications for aqueous SOA formation and impacts on both the chemical properties and health effects of OA.

scholarly journals Oxidation of low-molecular weight organic compounds in cloud droplets: global impact on tropospheric oxidants

2020 ◽  
Author(s):  
Simon Rosanka ◽  
Rolf Sander ◽  
Bruno Franco ◽  
Catherine Wespes ◽  
Andreas Wahner ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Aqueous Phase ◽  
Oxidation Products ◽  
Atmospheric Models ◽  
Cloud Droplets ◽  
Global Impact ◽  
Budget Analysis ◽  
Volatile Organic ◽  
Phase Chemical

Abstract. In liquid cloud droplets, superoxide anion (O−2(aq)) is known to quickly consume ozone (O3(aq)), which is relatively insoluble. The significance of this reaction as tropospheric O3 sink is sensitive to the abundance of O−2(aq) and therefore to the production of its main precursor, hydroperoxyl radical (HO2(aq)). The aqueous-phase oxidation of oxygenated volatile organic compounds (OVOCs) is the major source of HO2(aq) in cloud droplets. Hence, the lack of explicit aqueous-phase chemical kinetics in global atmospheric models leads to a general underestimation of clouds as O3 sinks. In this study, the importance of in-cloud OVOC oxidation for tropospheric composition is assessed by using the Chemistry As A Boxmodel Application (CAABA) and the global atmospheric model ECHAM/MESSy (EMAC), which are both capable of explicitly representing the relevant chemical transformations. For this analysis, three different in-cloud oxidation mechanisms are employed: (1) one including the basic oxidation of SO2(aq) via O3(aq) and H2O2(aq), which thus represents the capabilities of most global models, (2) the more advanced standard EMAC mechanism, which includes inorganic chemistry and simplified degradation of methane oxidation products, and (3) the detailed in-cloud OVOC oxidation scheme Jülich Aqueous-phase Mechanism of Organic Chemistry (JAMOC). By using EMAC, the global impact of each mechanism is assessed focusing mainly on tropospheric volatile organic compounds (VOCs), HOx (HOx = OH+HO2), and O3. This is achieved by performing a detailed HOx and O3 budget analysis in the gas- and aqueous-phase. The resulting changes are evaluated against O3 and methanol (CH3OH) satellite observations from the Infrared Atmospheric Sounding Interferometer (IASI) for 2015. In general, the explicit in-cloud oxidation leads to an overall reduction of predicted OVOCs levels, and reduces EMAC's overestimation of some OVOCs in the tropics. The in-cloud OVOC oxidation shifts the HO2 production from the gas- to the aqueous-phase. As a result, the O3 budget is perturbed with scavenging being enhanced and the gas-phase chemical losses being reduced. With the simplified in-cloud chemistry, about 13 Tg a−1 of O3 are scavenged, which increases to 336 Tg a−1 when JAMOC is used. The highest O3 reduction of 12 % is predicted in the upper troposphere/lower stratosphere (UTLS). These changes in the free troposphere significantly reduce the modelled tropospheric ozone columns, which are known to be generally overestimated by EMAC and other global atmospheric models.

scholarly journals THE COMBINATION OF FATTY ACIDS AND RELATED COMPOUNDS WITH SERUM ALBUMIN

1946 ◽  
Vol 162 (2) ◽  
pp. 181-198 ◽  
Author(s):  
Paul D. Boyer ◽  
Funston G. Lum ◽  
Gerald A. Ballou ◽  
J. Murray Luck ◽  
Randall G. Rice
Keyword(s):  
Fatty Acids ◽  
Serum Albumin ◽  
Related Compounds

Fungal pretreatment of pine wood to reduce the emission of volatile organic compounds

Holzforschung ◽  
2011 ◽  
Vol 65 (4) ◽  
Author(s):  
Daniel Stratev ◽  
Cornelia Gradinger ◽  
Thomas Ters ◽  
Karin Fackler ◽  
Thomas Kuncinger ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Unsaturated Fatty Acids ◽  
Marked Decrease ◽  
Fungal Growth ◽  
Wood Extractives ◽  
Pine Wood ◽  
Acetone Water ◽  
Fungal Pretreatment ◽  
Volatile Organic ◽  
Ophiostoma Piliferum

Abstract Sterilized pine wood strands were treated with the ascomycete Ophiostoma piliferum (Cartapip 97™) in an attempt to reduce aldehyde emissions through degradation of aldehyde-forming precursors. Wooden boards were then produced from the treated strands by means of a laboratory press. VOC emissions of these boards were characterized and the concentrations of seven major substances were followed for a period of 28 days in Markes μ-CTE micro-chambers employing Tenax-TDAS/GC/MS analytics. Boards made from treated strands showed a highly significant (P<0.001) reduction in aldehyde emissions by 70% compared to the control boards, while differences in the monoterpene emissions were not significant (P>0.05). Wood extractives from treated and untreated strands were also analyzed by GC/MS after milling and acetone/water extraction. A marked decrease of C18 unsaturated fatty acids was detected in agreement with the reduction of aldehyde emissions, and the monosaccharides as indicators of fungal growth were depleted and stilbenes and lignans were partially degraded.

scholarly journals Weekly patterns of México City's surface concentrations of CO, NO<sub>x</sub>, PM<sub>10</sub> and O<sub>3</sub> during 1986–2007

2008 ◽  
Vol 8 (17) ◽  
pp. 5313-5325 ◽  
Author(s):  
S. Stephens ◽  
S. Madronich ◽  
F. Wu ◽  
J. B. Olson ◽  
R. Ramos ◽  
...  
Keyword(s):  
Urban Areas ◽  
Distinct Pattern ◽  
Weekend Effect ◽  
The Past ◽  
Pollutant Concentrations ◽  
Photolysis Frequencies ◽  
Volatile Organic ◽  
The World ◽  
Urban Monitoring ◽  
Related Compounds

Abstract. Surface pollutant concentrations in México City show a distinct pattern of weekly variations similar to that observed in many other cities of the world. Measurements of the concentrations of carbon monoxide (CO), nitrogen oxides (NOx=NO+NO2), particulate matter smaller than 10 μm (PM10), and ozone (O3) collected hourly over 22 years (1986–2007) at 39 urban monitoring locations were analyzed. Morning concentrations of CO, NOx, and PM10 are lower on Saturdays and even more so on Sundays, compared to workdays (Monday–Friday), while afternoon O3 concentrations change minimally and are occasionally even higher. This weekend effect is empirical evidence that photochemical O3 production is NOx-inhibited, and to the extent that emissions of CO are proportional to those of reactive volatile organic compounds (VOCs), it is VOC-limited, at least in the urban areas for which the monitoring stations are representative. The VOC-limitation has increased in the past decade, due to decreases in the concentrations of CO (and presumably VOCs) and consequent decreases in the CO/NOx and VOC/NOx ratios. Enhancements of photolysis frequencies resulting from smaller weekend aerosol burdens are not negligible, but fall short of being an alternate explanation for the observed weekend effect. The strength of the weekend effect indicates that local radical termination occurs primarily via formation of nitric acid and other NOx-related compounds, some of which (e.g. peroxy acyl nitrates) can contribute to the regional NOx budget. While VOC emission reductions would be most effective in reducing local O3 production, NOx emission reduction may be more important for controlling regional oxidants.

Mass-Spectrometric Detection of Omega-Oxidation Products of Aliphatic Fatty Acids in Exhaled Breath

2017 ◽  
Vol 89 (19) ◽  
pp. 10329-10334 ◽  
Author(s):  
Martin Thomas Gaugg ◽  
Tobias Bruderer ◽  
Nora Nowak ◽  
Lara Eiffert ◽  
Pablo Martinez-Lozano Sinues ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Mass Spectrometric ◽  
Mass Spectrometric Detection ◽  
Oxidation Products ◽  
Exhaled Breath

scholarly journals Occurrence and distribution of ladderane oxidation products in different oceanic regimes

2012 ◽  
Vol 9 (7) ◽  
pp. 2407-2418 ◽  
Author(s):  
D. Rush ◽  
E. C. Hopmans ◽  
S. G. Wakeham ◽  
S. Schouten ◽  
J. S. Sinninghe Damsté
Keyword(s):  
Fatty Acids ◽  
Water Column ◽  
Arabian Sea ◽  
Degradation Products ◽  
Oxidation Products ◽  
Short Chain ◽  
Sediment Surface ◽  
Ammonium Oxidation ◽  
Anammox Activity ◽  
Sediment Matrix

Abstract. Ladderane fatty acids are commonly used as biomarkers for bacteria involved in anaerobic ammonium oxidation (anammox). These lipids have been experimentally shown to undergo aerobic microbial degradation to form short chain ladderane fatty acids. However, nothing is known of the production or the distribution of these oxic biodegradation products in the natural environment. In this study, we analysed marine water column particulate matter and sediment from three different oceanic regimes for the presence of ladderane oxidation products (C14 ladderane fatty acids) and of original ladderane fatty acids (C18 and C20 ladderane fatty acids). We found that ladderane oxidation products, i.e. C14 ladderane fatty acids, are already produced within the water column of the Arabian Sea oxygen minimum zone (OMZ) and thus only low amounts of oxygen (< 3 μM) are needed for the β-oxidation of original ladderane fatty acids to proceed. However, no short chain ladderane fatty acids were detected in the Cariaco Basin water column, where oxygen concentrations were below detection limit, suggesting that the β-oxidation pathway is inhibited by the absence of molecular oxygen, or that the microbes performing the degradation are not proliferating under these conditions. Comparison of distributions of ladderane fatty acids indicates that short chain ladderane fatty acids are mostly produced in the water column and at the sediment surface, before being preserved deeper in the sediments. Short chain ladderane fatty acids were abundant in Arabian Sea and Peru Margin sediments (ODP Leg 201), often in higher concentrations than the original ladderane fatty acids. In a sediment core taken from within the Arabian Sea OMZ, short chain ladderanes made up more than 90% of the total ladderanes at depths greater than 5 cm below sea floor. We also found short chain ladderanes in higher concentrations in hydrolysed sediment residues compared to those freely occurring in lipid extracts, suggesting that they had become bound to the sediment matrix. Furthermore, these matrix-bound short chain ladderanes were found at greater sediment depths than short chain ladderanes in the lipid extract, suggesting that binding to the sediment matrix aids the preservation of these lipids. Though sedimentary degradation of short chain ladderane fatty acids did occur, it appeared to be at a slower rate than that of the original ladderane fatty acids, and short chain ladderane fatty acids were found in sediments from the Late Pleistocene (~ 100 kyr). Together these results suggest that the oxic degradation products of ladderane fatty acids may be suitable biomarkers for past anammox activity in OMZs.

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