Effect of different cooking methods on lipid oxidation and formation of volatile compounds in foal meat.

PubMed

Domínguez, Rubén; Gómez, María; Fonseca, Sonia; Lorenzo, José M

2014-06-01

The influence of four different cooking methods (roasting, grilling, microwaving and frying) on cooking loss, lipid oxidation and volatile profile of foal meat was studied. Cooking loss were significantly (P<0.001) affected by thermal treatment, being higher (32.5%) after microwaving and lower after grilling (22.5%) and frying (23.8%). As expected, all the cooking methods increased TBARs content, since high temperature during cooking causes increased oxidation in foal steaks, this increase was significantly (P<0.001) higher when foal steaks were microwaved or roasted. The four different cooking methods led to increased total volatile compounds (between 366.7 and 633.1AU×10(6)/g dry matter) compared to raw steaks (216.4AU×10(6)/g dry matter). The roasted steaks showed the highest volatile content, indicating that increased cooking temperature increases the formation of volatile compounds. Aldehydes were the most abundant compounds in cooked samples, with amounts of 217.2, 364.5, 283.5 and 409.1AU×10(6)/g dry matter in grilled, microwaved, fried and roasted samples, respectively, whereas esters were the most abundant compounds in raw samples, with mean amounts of 98.8AU×10(6)/g dry matter. Copyright © 2014 Elsevier Ltd. All rights reserved.

Volatile profiles of Italian monovarietal extra virgin olive oils via HS-SPME-GC-MS: newly identified compounds, flavors molecular markers, and terpenic profile.

PubMed

Cecchi, Teresa; Alfei, Barbara

2013-12-01

This study aims to contribute to the knowledge of the commercial, sensory, and analytical characteristics of extra virgin olive oil (EVOO) from Italy (Marche region), renowned since ancient times. Headspace solid-phase micro-extraction (HS-SPME) was applied for the very first time to the sampling of volatile compounds of eleven typical Italian monocultivar EVOOs. Forty-eight compounds were characterised by GC-MS, some of them were only occasionally found in other EVOOs and some other were never detected before in any EVOO. Compounds belonging mainly to alcohols, esters, aldehydes, ketones and hydrocarbons chemical classes characterised the volatile profiles. The main volatile compounds detected in the EVOOs were the C6 compounds derived from polyunsaturated fatty acids, through the lipoxygenase pathway, in different proportion according to the specific cultivar. The results suggest that genetic factors strongly influence volatile formation and terpene hydrocarbons are claimed to be suitable markers of the geographic origin and genotype of the EVOO. Correlations among sensory attributes evaluated by a panel test and the presence of specific volatile compounds were highlighted for the very first time. The significance of the presence of some newly identified volatile compounds was discussed. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effect of hot air drying on volatile compounds of Flammulina velutipes detected by HS-SPME-GC-MS and electronic nose.

PubMed

Yang, Wenjian; Yu, Jie; Pei, Fei; Mariga, Alfred Mugambi; Ma, Ning; Fang, Yong; Hu, Qiuhui

2016-04-01

Volatile compounds are important factors that affect the flavor quality of Flammulina velutipes, but the changes occurring during hot air drying is still unclear. To clarify the dynamic changes of flavor components during hot air drying, comprehensive flavor characterization and volatile compounds of F. velutipes were evaluated using electronic nose technology and headspace solid phase micro-extraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS), respectively. Results showed that volatile components in F. velutipes significantly changed during hot air drying according to the principal component analysis and radar fingerprint chart of electronic nose. Volatile compounds of fresh F. velutipes consisted mainly of ketones, aldehydes and alcohols, and 3-octanone was the dominant compound. Drying process could significantly decrease the relative content of ketones and promoted the generation of alcohols, acids, and esters, which became the main volatile compounds of dried F. velutipes. These may provide a theoretical basis for the formation mechanism of flavor substances in dried F. velutipes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Key volatile compounds in red koji-shochu, a Monascus-fermented product, and their formation steps during fermentation.

PubMed

Rahayu, Yen Yen Sally; Yoshizaki, Yumiko; Yamaguchi, Keiko; Okutsu, Kayu; Futagami, Taiki; Tamaki, Hisanori; Sameshima, Yoshihiro; Takamine, Kazunori

2017-06-01

Red koji, which refers the solid culture grown koji mold on the steamed rice, is one of the ingredients of Asian fermented foods including the Japanese spirit shochu. This study was aimed at elucidating the characteristic flavor and key volatile compounds of red koji-shochu as well as the mechanism of their formation. Sensory evaluation showed that red koji-shochu has the distinctive flavors cheese, sour, milky, and oily. Fifteen key volatile compounds of red koji-shochu were identified by gas chromatography-mass spectrometry and high-performance liquid chromatography, and by comparison between red koji-shochu and white koji-shochu, as another typical shochu. The mash analysis revealed that ketone compounds and short-chain acids derive from red koji. Furthermore, although other key compounds were produced by yeast, it is highly likely that their concentrations were affected directly or indirectly by the high activities of protease and lipase in red koji. Copyright © 2016 Elsevier Ltd. All rights reserved.

ISOTOPIC (14C) AND CHEMICAL COMPOSITION OF ATMOSPHERIC VOLATILE ORGANIC COMPOUND FRACTIONS - PRECURSORS TO OZONE FORMATION

EPA Science Inventory

Atmospheric volatile organic compounds (VOCs) are an important factor in the production of ozone near ground level [3]. Many hydrocarbons originate from auto exhaust. However, a number of VOCs, e.g., isoprene, are known to be natural in origin. To develop reliable models for un...

Effect of the type of oil on the evolution of volatile compounds of taralli during storage.

PubMed

Giarnetti, Mariagrazia; Caponio, Francesco; Paradiso, Vito M; Summo, Carmine; Gomes, Tommaso

2012-03-01

Baking process leads to a huge quantity of newly formed volatile compounds, which play a major role in developing the flavor of the final product. The aim of this work was to investigate on the evolution of the volatile profile of taralli as a function of both the kind of oil used in the dough and the storage time. The volatile compounds from the taralli were extracted by headspace solid-phase microextraction and analyzed by gas-chromatography/mass spectrometry (GC/MS). Forty-four volatile compounds were identified in taralli, most of which produced by thermically induced reactions occurring during baking process, such as volatiles deriving from Maillard reaction and/or sugar degradation and lipid oxidation. The results obtained demonstrated the essential role played by the type of oil on the formation and on the release of volatile compounds. The volatile compounds significantly increased during storage and their individual levels were in most cases significantly lower in taralli made with extra virgin olive oil than in those made with refined oils. Finally, the taralli made with extra virgin olive oil, compared with those prepared with other vegetable oils, showed to be more resistant to oxidation, probably due to the presence of natural antioxidants. © 2012 Institute of Food Technologists®

Metabolic Impact of Redox Cofactor Perturbations on the Formation of Aroma Compounds in Saccharomyces cerevisiae

PubMed Central

Sanchez, Isabelle; Dequin, Sylvie; Camarasa, Carole

2015-01-01

Redox homeostasis is a fundamental requirement for the maintenance of metabolism, energy generation, and growth in Saccharomyces cerevisiae. The redox cofactors NADH and NADPH are among the most highly connected metabolites in metabolic networks. Changes in their concentrations may induce widespread changes in metabolism. Redox imbalances were achieved with a dedicated biological tool overexpressing native NADH-dependent or engineered NADPH-dependent 2,3-butanediol dehydrogenase, in the presence of acetoin. We report that targeted perturbation of the balance of cofactors (NAD+/NADH or, to a lesser extent, NADP+/NADPH) significantly affected the production of volatile compounds. In most cases, variations in the redox state of yeasts modified the formation of all compounds from the same biochemical pathway (isobutanol, isoamyl alcohol, and their derivatives) or chemical class (ethyl esters), irrespective of the cofactors. These coordinated responses were found to be closely linked to the impact of redox status on the availability of intermediates of central carbon metabolism. This was the case for α-keto acids and acetyl coenzyme A (acetyl-CoA), which are precursors for the synthesis of many volatile compounds. We also demonstrated that changes in the availability of NADH selectively affected the synthesis of some volatile molecules (e.g., methionol, phenylethanol, and propanoic acid), reflecting the specific cofactor requirements of the dehydrogenases involved in their formation. Our findings indicate that both the availability of precursors from central carbon metabolism and the accessibility of reduced cofactors contribute to cell redox status modulation of volatile compound formation. PMID:26475113

Extraction and formation dynamic of oak-related volatile compounds from different volume barrels to wine and their behavior during bottle storage.

PubMed

Pérez-Prieto, Luis J; López-Roca, Jose M; Martínez-Cutillas, Adrián; Pardo-Mínguez, Francisco; Gómez-Plaza, Encarna

2003-08-27

The extraction rate of furfuryl aldehydes, guaiacol, and 4-methylguaiacol, cis- and trans-oak lactone, and vanillin and the formation rate of furfuryl alcohol and the volatile phenols 4-ethylguaiacol and 4-ethylphenol have been studied in wines matured in different capacity oak barrels (220, 500, and 1000 L). Also, the behavior of these compounds during 1 year of wine bottle storage was followed. The lactones were extracted at a linear rate with large differences that depended on barrel volume. Those compounds related to oak toasting (guaiacol, 4-methylguaiacol, furfuryl aldehydes, and vanillin) seemed to be extracted faster during the first days of oak maturation except for vanillin, which required at least 3 months to accumulate in the wine. The volatile phenols, 4-ethylphenol and 4-ethylguaiacol, were formed in large quantities after the first 90 days of oak maturation, coinciding with the end of spring and beginning of summer. Wines matured in 1000-L oak barrels resulted in the lowest levels of volatile compound accumulation. During bottle storage, some compounds decreased in their concentration (5-methylfurfural, vanillin), others experienced increases in their levels (lactones, furfural, 4-ethylguaiacol, 4-ethylphenol), and the concentration of other compounds hardly changed (guaiacol, furfuryl alcohol).

Volatile compounds formation in alcoholic fermentation from grapes collected at 2 maturation stages: influence of nitrogen compounds and grape variety.

PubMed

Martínez-Gil, Ana M; Garde-Cerdán, Teresa; Lorenzo, Cándida; Lara, José Félix; Pardo, Francisco; Salinas, M Rosario

2012-01-01

The aim of this work was to study the influence of nitrogen compounds on the formation of volatile compounds during the alcoholic fermentation carried out with 4 nonaromatic grape varieties collected at 2 different maturation stages. To do this, Monastrell, Merlot, Syrah, and Petit Verdot grapes were collected 1 wk before harvest and at harvest. Then, the musts were inoculated with the same Saccharomyces cerevisiae yeast strain and were fermented in the same winemaking conditions. Amino acids that showed the highest and the lowest concentration in the must were the same, regardless of the grape variety and maturation stage. Moreover, the consumption of amino acids during the fermentation increased with their concentration in the must. The formation of volatile compounds was not nitrogen composition dependent. However, the concentration of amino acids in the must from grapes collected 1 wk before harvest can be used as a parameter to estimate the concentration of esters in wines from grapes collected at harvest and therefore to have more information to know the grape oenological capacity. Application of principal components analysis (PCA) confirmed the possibility to estimate the concentration of esters in the wines with the concentration of nitrogen compounds in the must. © 2011 Institute of Food Technologists®

Volatile compound profile of sous-vide cooked lamb loins at different temperature-time combinations.

PubMed

Roldán, Mar; Ruiz, Jorge; Del Pulgar, José Sánchez; Pérez-Palacios, Trinidad; Antequera, Teresa

2015-02-01

Lamb loins were subjected to sous-vide cooking at different combinations of temperature (60 and 80°C) and time (6 and 24h) to assess the effect on the volatile compound profile. Major chemical families in cooked samples were aliphatic hydrocarbons and aldehydes. The volatile compound profile in sous-vide cooked lamb loin was affected by the cooking temperature and time. Volatile compounds arising from lipid oxidation presented a high abundance in samples cooked at low or moderate cooking conditions (60°C for 6 and 24h, 80°C for 6h), while a more intense time and temperature combination (80°C for 24h) resulted on a higher concentration of volatile compounds arising from Strecker degradations of amino acids, as 2-methylpropanal and 3-methylbutanal. Therefore, sous-vide cooking at moderately high temperatures for long times would result in the formation of a stronger meaty flavor and roast notes in lamb meat. Copyright © 2014 Elsevier Ltd. All rights reserved.

Volatile organic compounds at oil and natural gas production well pads in Colorado and Texas using passive samplers

EPA Science Inventory

A pilot study was conducted in application of the U.S. Environmental Protection Agency (EPA) Methods 325A/B variant for monitoring volatile organic compounds (VOCs) near two oil and natural gas (ONG) production well pads in the Texas Barnett Shale formation and Colorado Denver&nd...

Salt lakes of Western Australia - Natural abiotic formation of volatile organic compounds

NASA Astrophysics Data System (ADS)

Krause, T.; Studenroth, S.; Mulder, I.; Tubbesing, C.; Kotte, K.; Ofner, J.; Junkermann, W.; Schöler, H. F.

2012-04-01

Western Australia is a semi-/arid region that is heavily influenced by global climate change and agricultural land use. The area is known for its many ephemeral saline and hypersaline lakes with a wide range of hydrogeochemical parameters that have gradually changed over the last fifty years. Historically, the region was covered by eucalyptus trees and shrubs, but was cleared mainly within 10 years after WWII to make room for wheat and live stock. After the clearance of the deep rooted native plants the groundwater started to rise, bringing increased amounts of dissolved salts and minerals to the surface and discharging them into streams and lakes. Thus most of Western Australia is influenced by secondary salinisation (soil salting) [1]. Another problem is that the discharged minerals affect the pH of ground and surface water, which ranges from acidic to slightly basic. During the 2011 campaign surface water was measured with a pH between 2.5 and 7.1. Another phenomenon in Western Australia is the decrease of rainfall over the last decades assumed to be linked to the secondary salinisation. The rising saline and mineral rich groundwater increases the biotical and abiotical activity of the salt lakes. Halogenated and non-halogenated volatile organic compounds emitted from those lakes undergo fast oxidation and chemical reactions to form small particles modifying cloud microphysics and thus suppressing rain events [2]. Our objective is to gain a better understanding of this extreme environment with its hypersaline acidic lakes with regard to the potential abiotic formation of volatile organic compounds and its impact on the local climate. In spring 2011 fifty-three sediment samples from ten salt lakes in the Lake King region where taken, freeze-dried and ground. In order to simulate the abiotic formation of volatile organic compounds the soil samples were resuspended with water in gas-tight headspace vials. The headspace was measured using a purge and trap GC/MS. Especially the acidic lakes are sources for trihalomethanes in agreement with laboratory studies on model compounds like catechol [3]. Other compounds that are formed are chloromethane, -butane, -hexane and heptane as well as monocyclic terpenes and furan derivatives. Additionally, there are different sulphur compounds such as thiophene derivatives, carbon disulfide and dimethyl sulfide. Western Australia offers a variety of hypersaline environments with various hydrogeochemical parameters that will help to understand the abiotic formation of different volatile organic compounds. The field of research includes the complex relationships between agriculture, secondary salinisation and particle formation from volatile organic compounds emitted from the salt lakes. [1] Williams, 2001, Hydrobiologia, 466, 329-337. [2] Junkermann et al., 2009, Atmos. Chem. Phys., 9, 6531-6539. [3] Huber et al., 2009, Environ. Sci. Technol., 43 (13), 4934-4939.

Volatile compounds and odor traits of dry-cured ham (Prosciutto crudo) irradiated by electron beam and gamma rays

NASA Astrophysics Data System (ADS)

Kong, Qiulian; Yan, Weiqiang; Yue, Ling; Chen, Zhijun; Wang, Haihong; Qi, Wenyuan; He, Xiaohua

2017-01-01

Prosciutto crudo samples were irradiated at 0, 3 and 6 kGy by gamma rays (GR) and electron beam (EB), respectively. The odor scores and volatile compounds were examined after 7 days storage at 4 °C. Volatile compounds from samples without and with irradiation at 6 kGy were analyzed by GC-MS. Fifty-nine compounds were identified, including terpenes, aldehydes, alcohols, ketones, alkanes, esters, aromatic hydrocarbons and acids. Both GR and EB irradiation resulted in formation of (Z)-7-Hexadecenal, cis-9-hexadecenal, tetradecane, E-9-tetradecen-1-ol formate, and losing of hexadecamethyl-heptasiloxane and decanoic acid-ethyl ester in hams. However, GR irradiation caused additional changes, such as formation of undecane and phthalic acid-2-cyclohexylethyl butyl ester, significantly higher level of 1-pentadecene, and losing of (E, E)-2,4-decadienal and octadecane. EB was shown to be better in maintaining ham's original odor than GR. Our results suggest that EB irradiation is a promising method for treatment of ready to eat hams as it exerts much less negative effect on the flavor of hams compared to GR irradiation.

Effects of soy sauce and packaging method on volatile compounds and lipid oxidation of cooked irradiated beef patties

NASA Astrophysics Data System (ADS)

Kim, Hyun-Wook; Lee, Soo-Yeon; Hwang, Ko-Eun; Song, Dong-Heon; Kim, Yong-Jae; Ham, Yun-Kyung; Lee, Choong-Hee; Choi, Yun-Sang; Lee, Ju-Woon; Kim, Cheon-Jei

2014-10-01

The objective of this study is to determine the effect of soy sauce on volatile compounds and lipid oxidation of cooked irradiated beef patties. Sulfur-containing volatile components, which are produced by irradiation, were not found in all treatments. Volatile components derived from soy sauce, such as 3-hydroxy-2-butanone, acetic acid, 3-methyl-1-butanol and 2-methyl-1-butanol, were detected in beef patties containing soy sauce regardless of irradiation and packaging method. Volatile aldehydes, including hexanal, significantly decreased the irradiated beef patty prepared with soy sauce compared to those of irradiated beef patty made with NaCl at 1 day and 5 days after irradiation. In addition, combined use of vacuum packaging and soy sauce treatments could inhibit the formation of volatile compounds and 2-thiobarbituric acid reactive substances during chilled storage. Therefore, the use of soy sauce in cooked and irradiated beef could reduce the production of volatile components associated with the irradiation-induced off-flavor and lipid oxidation.

Sunlight exclusion from Muscat grape alters volatile profiles during berry development.

PubMed

Zhang, Haohao; Fan, Peige; Liu, Cuixia; Wu, Benhong; Li, Shaohua; Liang, Zhenchang

2014-12-01

The effects of sunlight exclusion on the volatile profiles of grapes during different stages of berry development were investigated by placing clusters of grapes in special boxes. Terpenes and aldehydes were the main volatile compounds in the ripe 'Jingxiangyu' berries. Sunlight exclusion was found to change volatile profiles at any stage. Sunlight exclusion from berries significantly inhibited the synthesis and accumulation of terpenes, which contribute to the characteristic aroma of Muscat grapes. However, sunlight exclusion during berry formation and veraison promoted the accumulation of aldehydes, alcohols, and ketones during the ripening stage. These results may provide important information regarding the metabolism of volatile compounds in grapes. Copyright © 2014 Elsevier Ltd. All rights reserved.

Production of extremely low volatile organic compounds from biogenic emissions: Measured yields and atmospheric implications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jokinen, Tuija; Berndt, Torsten; Makkonen, Risto

2015-06-09

Extremely low volatility organic compounds (ELVOC) are suggested to promote aerosol particle formation and cloud condensation nuclei (CCN) production in the atmosphere. We show that the capability of biogenic VOC (BVOC) to produce ELVOC depends strongly on their chemical structure and relative oxidant levels. BVOC with an endocyclic double bond, representative emissions from, e.g., boreal forests, efficiently produce ELVOC from ozonolysis. Compounds with exocyclic double bonds or acyclic compounds including isoprene, emission representative of the tropics, produce minor quantities of ELVOC, and the role of OH radical oxidation is relatively larger. Implementing these findings into a global modeling framework showsmore » that detailed assessment of ELVOC production pathways is crucial for understanding biogenic secondary organic aerosol and atmospheric CCN formation.« less

Sensitivity-Based VOC Reactivity Calculation

EPA Science Inventory

Volatile Organic Compound (VOC) reactivity scales are used to compare the ozone-forming potentials of various compounds. The comparison allows for substitution of compounds to lessen formation of ozone from paints, solvents, and other products. Current reactivity scales for VOC c...

Lipid oxidation in baked products: impact of formula and process on the generation of volatile compounds.

PubMed

Maire, Murielle; Rega, Barbara; Cuvelier, Marie-Elisabeth; Soto, Paola; Giampaoli, Pierre

2013-12-15

This paper investigates the effect of ingredients on the reactions occurring during the making of sponge cake and leading to the generation of volatile compounds related to flavour quality. To obtain systems sensitive to lipid oxidation (LO), a formulation design was applied varying the composition of fatty matter and eggs. Oxidation of polyunsaturated fatty acids (PUFA) and formation of related volatile compounds were followed at the different steps of cake-making. Optimised dynamic Solid Phase Micro Extraction was applied to selectively extract either volatile or semi-volatile compounds directly from the baking vapours. We show for the first time that in the case of alveolar baked products, lipid oxidation occurs very early during the step of dough preparation and to a minor extent during the baking process. The generation of lipid oxidation compounds depends on PUFA content and on the presence of endogenous antioxidants in the raw matter. Egg yolk seemed to play a double role on reactivity: protecting unsaturated lipids from oxidation and being necessary to generate a broad class of compounds of the Maillard reaction during baking and linked to the typical flavour of sponge cake. Copyright © 2013 Elsevier Ltd. All rights reserved.

Ripening and storage conditions of Chétoui and Arbequina olives: Part I. Effect on olive oils volatiles profile.

PubMed

Hachicha Hbaieb, Rim; Kotti, Faten; Gargouri, Mohamed; Msallem, Monji; Vichi, Stefania

2016-07-15

The distinctive aroma of virgin olive oil is mainly attributed to its volatile profile including components responsible for positive attributes and others for sensory defects resulting from chemical oxidation and exogenous enzymes. For this reason, the evolution of volatile compounds from Chétoui and Arbequina virgin olive oils during olive ripening and storage (at 4 and 25 °C during 4 weeks) was investigated. The profile of volatile phenols during olive storage was also studied. Quantitative differences in the volatile compounds during olive storage at 4 and 25 °C according to olive cultivar was determined. Concerning the volatile phenols, the Arbequina olives were the most affected by high storage temperature, as the formation of these compounds, especially 4-ethyl and 4-vinyl derivatives of phenol and guaiacol were more noticeable in Arbequina oils extracted from stored fruits at 25 °C. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ground-water quality beneath an urban residential and commercial area, Montgomery, Alabama, 1999-2000

USGS Publications Warehouse

Robinson, James L.

2002-01-01

The Black Warrior River aquifer, which is composed of the Coker, Gordo, and Eutaw Formations, supplies more than 50 percent of the ground water used for public water supply in the Mobile River Basin. The city of Montgomery, Alabama, is partially built upon a recharge area for the Black Warrior River aquifer, and is one of many major population centers that depend on the Black Warrior River aquifer for public water supply. To represent the baseline ground-water quality in the Black Warrior River aquifer, water samples were collected from 30 wells located in a low-density residential or rural setting; 9 wells were completed in the Coker Formation, 9 wells in the Gordo Formation, and 12 wells in the Eutaw Formation. To describe the ground-water quality beneath Montgomery, Alabama, water samples also were collected from 30 wells located in residential and commercial areas of Montgomery, Alabama; 16 wells were completed in the Eutaw Formation, 8 wells in alluvial deposits, and 6 wells in terrace deposits. The alluvial and terrace deposits directly overlie the Eutaw Formation with little or no hydraulic separation. Ground-water samples collected from both the rural and urban wells were analyzed for physical properties, major ions, nutrients, metals, volatile organic compounds, and pesticides. Samples from the urban wells also were analyzed for bacteria, chlorofluorocarbons, dissolved gases, and sulfur hexafluoride. Ground-water quality beneath the urban area was compared to baseline water quality in the Black Warrior River aquifer.Compared to the rural wells, ground-water samples from urban wells contained greater concentrations or more frequent detections of chloride and nitrate, and the trace metals aluminium, chromium, cobalt, copper, nickel, and zinc. Pesticides and volatile organic compounds were detected more frequently and in greater concentrations in ground-water samples collected from urban wells than in ground-water samples from rural wells.The Spearman rho test was used to check for statistically significant covariance among urban ground-water quality and land-use type. The number of pesticides and volatile organic compounds detected and concentrations of nickel increased as the percentage of residential land use increased. Greater nickel concentrations also were associated with a greater number of volatile organic compounds detected. As the percentage of commercial land use increased, the numbers of pesticides and volatile organic compounds detected decreased. The number of pesticides detected in the urban ground-water samples increased as concentrations of nitrite plus nitrate increased; the number of pesticides detected and the concentrations of nitrite plus nitrate decreased as the age of the ground water increased. These correlations may indicate that, with time, pesticides and nitrate are removed from the ground-water system by physical, chemical, or biological processes.The effects of surficial geology on the occurrence of pesticides and volatile organic compounds was investigated by calculating frequencies of detection. The detection frequency for pesticides was greater for urban samples collected from wells where the surficial geology is sand than for urban samples collected from wells where the surficial geology is clay. The frequency of detection of volatile organic compounds did not show this relation.

Effect of nitrite on the odourant volatile fraction of cooked ham.

PubMed

Thomas, Caroline; Mercier, Frédéric; Tournayre, Pascal; Martin, Jean-Luc; Berdagué, Jean-Louis

2013-08-15

The aim of this work was to reliably identify the key odour compounds in cooked ham and acquire new knowledge on the role of sodium nitrite on the formation of its aroma. Gas chromatography coupled with mass spectrometry and (or) olfactometry was used. In all, 24 odourants were identified in the volatile fraction of cooked ham. Their main origins are discussed. Orthonasal sniffing of the hams was used to study how these substances contributed to the overall aroma of the product. The aroma of cooked ham is a balance between that of certain sulfur compounds produced during cooking and that of oxidation compounds commonly found in cooked meats. In the absence of nitrite, this balance is disturbed by extensive formation of oxidation compounds that mask the meaty notes induced by the sulfur compounds. Copyright © 2013 Elsevier Ltd. All rights reserved.

Pollution data analysis and characteristics of volatile organic compounds in the environment

NASA Astrophysics Data System (ADS)

Wang, Qi; Wang, Chěn; Hou, Lujian; Lv, Bo; WANG, Chén

2018-06-01

Volatile organic compounds (VOCs) have a wide range of sources and have a significant impact on the ecological environment and human health, which have attracted wide attention of many researchers. In this paper, the pollution characteristics of VOCs, the role of VOCs in atmospheric chemistry including OH reaction reactivity (LOH), Ozone Formation Potential (OFP) and SOA generation potential (SOAP), VOCs source apportionment were discussed and reviewed.

Secondary organic aerosol formation and composition from the photo-oxidation of methyl chavicol (estragole)

NASA Astrophysics Data System (ADS)

Pereira, K. L.; Hamilton, J. F.; Rickard, A. R.; Bloss, W. J.; Alam, M. S.; Camredon, M.; Muñoz, A.; Vásquez, M.; Borrás, E.; Ródenas, M.

2013-12-01

The increasing demand for palm oil for uses in biofuel and food products is leading to rapid expansion of oil palm agriculture. Methyl chavicol (also known as estragole and 1-allyl-4-methoxybenzene) is an oxygenated biogenic volatile organic compound that was recently identified as the main floral emission from an oil palm plantation in Malaysian Borneo. The emissions of methyl chavicol observed may impact regional atmospheric chemistry, but little is known of its ability to form secondary organic aerosol (SOA). The photo-oxidation of methyl chavicol was investigated at the European Photoreactor chamber as a part of the atmospheric chemistry of methyl chavicol (ATMECH) project. Aerosol samples were collected using a particle into liquid sampler (PILS) and analysed offline using an extensive range of instruments including; high performance liquid chromatography mass spectrometry (HPLC-ITMS), high performance liquid chromatography quadrupole time-of-flight mass spectrometry (HPLC-QTOFMS) and Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). The SOA yield was determined as 18-29% depending on initial precursor (VOC : NOx) mixing ratios. In total, 59 SOA compounds were observed and the structures of 10 compounds have been identified using high resolution tandem mass spectrometry. The addition of hydroxyl and/or nitro functional groups to the aromatic ring appears to be an important mechanistic pathway for aerosol formation. This results in the formation of compounds with both low volatility and high O : C ratios, where functionalisation rather than fragmentation is mainly observed as a~result of the stability of the ring. The SOA species observed can be characterized as semi-volatile to low volatile oxygenated organic aerosol (SVOOA and LVOOA) components and therefore may be important in aerosol formation and growth.

Ammonia Released by Streptomyces aburaviensis Induces Droplet Formation in Streptomyces violaceoruber.

PubMed

Schmidt, Kathrin; Spiteller, Dieter

2017-08-01

Streptomyces violaceoruber grown in co-culture with Streptomyces aburaviensis produces an about 17-fold higher volume of droplets on its aerial mycelium than in single-culture. Physical separation of the Streptomyces strains by either a plastic barrier or by a dialysis membrane, which allowed communication only by the exchange of volatile compounds or diffusible compounds in the medium, respectively, still resulted in enhanced droplet formation. The application of molecular sieves to bioassays resulted in the attenuation of the droplet-inducing effect of S. aburaviensis indicating the absorption of the compound. 1 H-NMR analysis of molecular-sieve extracts and the selective indophenol-blue reaction revealed that the volatile droplet-inducing compound is ammonia. The external supply of ammonia in biologically relevant concentrations of ≥8 mM enhanced droplet formation in S. violaceoruber in a similar way to S. aburaviensis. Ammonia appears to trigger droplet production in many Streptomyces strains because four out of six Streptomyces strains exposed to ammonia exhibited induced droplet production.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldstein, A. H.; Yee, L. D.; Issacman-VanWertz, G.

In areas where biogenic emissions are oxidized in the presence of anthropogenic pollutants such as SO2, NOx, and black carbon, it has become increasingly apparent that secondary organic aerosol (SOA) formation from biogenic volatile organic compounds (VOCs) is substantially enhanced. Research is urgently needed to elucidate fundamental processes of natural and anthropogenically influenced VOC oxidation and the contribution of these processes to SOA formation. GoAmazon 2014/15 afforded study of the chemical transformations in the region downwind of Manaus, Brazil, where local biogenic VOC emissions are high, and their chemical oxidation can be studied both inside and outside of the urbanmore » plume to differentiate the role of anthropogenic influence on secondary aerosol formation during oxidation of these natural VOC emissions. To understand the connection between primary biogenic VOC emissions and their secondary products that form aerosols, we made time-resolved molecular level measurements by deploying a Semi-Volatile Thermal Desorption Aerosol Gas Chromatograph (SV-TAG) and a sequential filter sampler during two intensive operational periods (IOPs) of the GoAmazon 2014/15 field campaign. The SV-TAG measured semi-volatile organic compounds in both the gas and particle phases and the sequential filter sampler collected aerosols on quartz fiber filters in four-hour increments used for offline analysis. SV-TAG employed novel online derivatization that provided chemical speciation of highly oxygenated or functionalized compounds that comprise a substantial fraction of secondary organic aerosols, yet are poorly characterized. It also provided partitioning of these compounds between the vapor and particle phases at sufficient time resolution to define the importance of competing atmospheric processes. These measurements were supported by offline analysis of the filters using two-dimensional gas chromatography (GC x GC) with high-resolution time-of-flight mass spectrometry (HR-TOF-MS) using both electron impact (EI) and soft vacuum ultraviolet (VUV) ionization with derivatization. Speciated chemical data from SV-TAG and filter measurements were used to elucidate the relative importance of potential oxidation pathways by providing detailed information on the product distribution from atmospheric reactions and the quantification of known tracers for various oxidation pathways. Together, these techniques provided unequivocal molecular identification of a wide range of atmospheric organic compounds spanning the volatile, semi-volatile, and non-volatile phases. This level of chemical characterization provided insight into the chemical and physical processes that control the atmospheric oxidation of biogenic VOC and subsequent formation of SOA.« less

Emission of intermediate, semi and low volatile organic compounds from traffic and their impact on secondary organic aerosol concentrations over Greater Paris

NASA Astrophysics Data System (ADS)

Sartelet, K.; Zhu, S.; Moukhtar, S.; André, M.; André, J. M.; Gros, V.; Favez, O.; Brasseur, A.; Redaelli, M.

2018-05-01

Exhaust particle emissions are mostly made of black carbon and/or organic compounds, with some of these organic compounds existing in both the gas and particle phases. Although emissions of volatile organic compounds (VOC) are usually measured at the exhaust, emissions in the gas phase of lower volatility compounds (POAvapor) are not. However, these gas-phase emissions may be oxidised after emission and enhance the formation of secondary organic aerosols (SOA). They are shown here to contribute to most of the SOA formation in Central Paris. POAvapor emissions are usually estimated from primary organic aerosol emissions in the particle phase (POA). However, they could also be estimated from VOC emissions for both gasoline and diesel vehicles using previously published measurements from chamber measurements. Estimating POAvapor from VOC emissions and ageing exhaust emissions with a simple model included in the Polyphemus air-quality platform compare well to measurements of SOA formation performed in chamber experiments. Over Greater Paris, POAvapor emissions estimated using POA and VOC emissions are compared using the HEAVEN bottom-up traffic emissions model. The impact on the simulated atmospheric concentrations is then assessed using the Polyphemus/Polair3D chemistry-transport model. Estimating POAvapor emissions from VOC emissions rather than POA emissions lead to lower emissions along motorway axes (between -50% and -70%) and larger emissions in urban areas (up to between +120% and +140% in Central Paris). The impact on total organic aerosol concentrations (gas plus particle) is lower than the impact on emissions: between -8% and 25% along motorway axes and in urban areas respectively. Particle-phase organic concentrations are lower when POAvapor emissions are estimated from VOC than POA emissions, even in Central Paris where the total organic aerosol concentration is higher, because of different assumptions on the emission volatility distribution, stressing the importance of characterizing not only the emission strength, but also the emission volatility distribution.

Does Enzymatic Hydrolysis of Glycosidically Bound Volatile Compounds Really Contribute to the Formation of Volatile Compounds During the Oolong Tea Manufacturing Process?

PubMed

Gui, Jiadong; Fu, Xiumin; Zhou, Ying; Katsuno, Tsuyoshi; Mei, Xin; Deng, Rufang; Xu, Xinlan; Zhang, Linyun; Dong, Fang; Watanabe, Naoharu; Yang, Ziyin

2015-08-12

It was generally thought that aroma of oolong tea resulted from hydrolysis of glycosidically bound volatiles (GBVs). In this study, most GBVs showed no reduction during the oolong tea manufacturing process. β-Glycosidases either at protein or gene level were not activated during the manufacturing process. Subcellular localization of β-primeverosidase provided evidence that β-primeverosidase was located in the leaf cell wall. The cell wall remained intact during the enzyme-active manufacturing process. After the leaf cell disruption, GBV content was reduced. These findings reveal that, during the enzyme-active process of oolong tea, nondisruption of the leaf cell walls resulted in impossibility of interaction of GBVs and β-glycosidases. Indole, jasmine lactone, and trans-nerolidol were characteristic volatiles produced from the manufacturing process. Interestingly, the contents of the three volatiles was reduced after the leaf cell disruption, suggesting that mechanical damage with the cell disruption, which is similar to black tea manufacturing, did not induce accumulation of the three volatiles. In addition, 11 volatiles with flavor dilution factor ≥4(4) were identified as relatively potent odorants in the oolong tea. These results suggest that enzymatic hydrolysis of GBVs was not involved in the formation of volatiles of oolong tea, and some characteristic volatiles with potent odorants were produced from the manufacturing process.

Impact of cooking and handling conditions on furanic compounds in breaded fish products.

PubMed

Pérez-Palacios, T; Petisca, C; Henriques, R; Ferreira, I M P L V O

2013-05-01

This study evaluates the influence of cooking and handling conditions on the quantity of furanic compounds (furan, 2-furfural, furfuryl alcohol, 2-pentylfuran, 5-hydroxymethylfurfural) in breaded fish products. Oven-baking and reheating in the microwave lead to low furanic compounds formation in comparison with deep-frying. The use of olive oil for deep-frying promoted higher levels of furanic compounds than sunflower oil. The amounts of these compounds diminished as the temperature and time of deep-frying decreased as well as after a delay after deep-frying. Thus, the generation of furanic compounds can be minimized by adjusting the cooking method and conditions, such as using an electric oven, deep-frying in sunflower oil at 160°C during 4min, or waiting 10min after cooking. However, these conditions that reduce furanic compounds levels also reduce the content of volatile compounds related to the aroma and flavour of fried foods. In this sense, new efforts should be done to reduce the formation of furanic compounds without being detrimental to the volatile profile. Copyright © 2013 Elsevier Ltd. All rights reserved.

Potential of secondary aerosol formation from Chinese gasoline engine exhaust.

PubMed

Du, Zhuofei; Hu, Min; Peng, Jianfei; Guo, Song; Zheng, Rong; Zheng, Jing; Shang, Dongjie; Qin, Yanhong; Niu, He; Li, Mengren; Yang, Yudong; Lu, Sihua; Wu, Yusheng; Shao, Min; Shuai, Shijin

2018-04-01

Light-duty gasoline vehicles have drawn public attention in China due to their significant primary emissions of particulate matter and volatile organic compounds (VOCs). However, little information on secondary aerosol formation from exhaust for Chinese vehicles and fuel conditions is available. In this study, chamber experiments were conducted to quantify the potential of secondary aerosol formation from the exhaust of a port fuel injection gasoline engine. The engine and fuel used are common in the Chinese market, and the fuel satisfies the China V gasoline fuel standard. Substantial secondary aerosol formation was observed during a 4-5hr simulation, which was estimated to represent more than 10days of equivalent atmospheric photo-oxidation in Beijing. As a consequence, the extreme case secondary organic aerosol (SOA) production was 426±85mg/kg-fuel, with high levels of precursors and OH exposure. The low hygroscopicity of the aerosols formed inside the chamber suggests that SOA was the dominant chemical composition. Fourteen percent of SOA measured in the chamber experiments could be explained through the oxidation of speciated single-ring aromatics. Unspeciated precursors, such as intermediate-volatility organic compounds and semi-volatile organic compounds, might be significant for SOA formation from gasoline VOCs. We concluded that reductions of emissions of aerosol precursor gases from vehicles are essential to mediate pollution in China. Copyright © 2017. Published by Elsevier B.V.

Contribution of l-theanine to the formation of 2,5-dimethylpyrazine, a key roasted peanutty flavor in Oolong tea during manufacturing processes.

PubMed

Guo, Xiangyang; Song, Chuankui; Ho, Chi-Tang; Wan, Xiaochun

2018-10-15

l-Theanine, the most abundant amino acid in tea, is widely believed to be associated with the tea taste, however, its contribution to the formation of tea aroma is still unknown. Volatiles were determined and nitrogen-containing compounds formed during manufacturing processes were quantified. Lower levels of total sugar and l-theanine were detected in the Oolong tea product undergoing full fire processing (FFOT) suggesting that l-theanine probably involved in the volatile formation during manufacturing processes. Methylpyrazine and 2,5-dimethylpyrazine, two newly formed compounds in FFOT, together with other volatiles were successfully detected in a model thermal reaction of d-glucose and l-theanine (GT-MTR) but not detectable in thermal reactions with single d-glucose (G-MTR) or l-theanine (T-MTR). The concentration of 2,5-dimethylpyrazine increased significantly by adding additional l-theanine to 2nd roasted tea. Our study demonstrated that l-theanine, at least partly, contributed to the formation of 2,5-dimethylpyrazine, a key roasted peanutty flavor in Oolong tea. Copyright © 2018. Published by Elsevier Ltd.

78 FR 11119 - Air Quality: Revision to Definition of Volatile Organic Compounds-Exclusion of trans

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-15

... tropospheric ozone formation. In the ``Rules and Regulations'' section of this Federal Register, we are making... compound makes a negligible contribution to tropospheric ozone formation.\\1\\ We are publishing a direct... standards for ozone under title I of the Clean Air Act (CAA). This proposed revision would add trans 1...

Changes in chemical composition of frozen coated fish products during deep-frying.

PubMed

Pérez-Palacios, Trinidad; Petisca, Catarina; Casal, Susana; Ferreira, Isabel M P L V O

2014-03-01

This work evaluates the influence of deep-frying coated fish products on total fat, fatty acid (FA) and amino acid profile, and on the formation of volatile compounds, with special attention on furan and its derivatives due to their potential harmful characteristics. As expected, deep-frying in sunflower oil increased linoleic acid content, but total fat amount increased only by 2% on a dry basis. Eicosapentanoic and docosahexanoic acids were preserved while γ- and α-linoleic acids were oxidised. Deep-frying also induces proteolysis, releasing free AA, and the formation of volatile compounds, particularly aldehydes and ketones arising from polyunsaturated FA. In addition, high quantities of furanic compounds, particularly furan and furfuryl alcohol, are generated during deep-frying coated fish. The breaded crust formed could contribute simultaneously for the low uptake of fat, preservation of long chain n-3 FA, and for the high amounts of furanic compounds formed during the deep-frying process.

Oxidation-reduction catalyst and its process of use

NASA Technical Reports Server (NTRS)

Schryer, Jacqueline L. (Inventor); Oglesby, Donald M. (Inventor); Jordan, Jeffrey D. (Inventor); Watkins, Anthony Neal (Inventor)

2008-01-01

This invention relates generally to a ruthenium stabilized oxidation-reduction catalyst useful for oxidizing carbon monoxide, and volatile organic compounds, and reducing nitrogen oxide species in oxidizing environments, substantially without the formation of toxic and volatile ruthenium oxide species upon said oxidizing environment being at high temperatures.

Characterization of Aronia melanocarpa volatiles by headspace-solid-phase microextraction (HS-SPME), simultaneous distillation/extraction (SDE), and gas chromatography-olfactometry (GC-O) methods.

PubMed

Kraujalytė, Vilma; Leitner, Erich; Venskutonis, Petras Rimantas

2013-05-22

The profiles of volatile constituents of berry fruit of two Aronia melanocarpa genotypes were evaluated by headspace-solid-phase microextraction (HS-SPME), simultaneous distillation and extraction (SDE), and gas chromatography-olfactometry (GC-O). In total, 74 volatile compounds were identified in chokeberry juice, 3-penten-2-one, 3,9-epoxy-p-menth-1-ene, and benzaldehyde being the most abundant constituents; however, their percentage concentrations were remarkably different in the HS-SPME and SDE profiles. Twenty two aroma-active compounds were detected and characterized by the trained panelists in HS-SPME using GC-O detection frequency analysis. Olfactometry revealed that ethyl-2-methyl butanoate, ethyl-3-methyl butanoate, ethyl decanoate ("fruity" aroma notes), nonanal ("green" notes), unidentified compound possessing "moldy" odor, and some other volatiles may be very important constituents in formation of chokeberry aroma of both analyzed plant cultivars.

Improvement of a headspace solid phase microextraction-gas chromatography/mass spectrometry method for the analysis of wheat bread volatile compounds.

PubMed

Raffo, Antonio; Carcea, Marina; Castagna, Claudia; Magrì, Andrea

2015-08-07

An improved method based on headspace solid phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME/GC-MS) was proposed for the semi-quantitative determination of wheat bread volatile compounds isolated from both whole slice and crust samples. A DVB/CAR/PDMS fibre was used to extract volatiles from the headspace of a bread powdered sample dispersed in a sodium chloride (20%) aqueous solution and kept for 60min at 50°C under controlled stirring. Thirty-nine out of all the extracted volatiles were fully identified, whereas for 95 other volatiles a tentative identification was proposed, to give a complete as possible profile of wheat bread volatile compounds. The use of an array of ten structurally and physicochemically similar internal standards allowed to markedly improve method precision with respect to previous HS-SPME/GC-MS methods for bread volatiles. Good linearity of the method was verified for a selection of volatiles from several chemical groups by calibration with matrix-matched extraction solutions. This simple, rapid, precise and sensitive method could represent a valuable tool to obtain semi-quantitative information when investigating the influence of technological factors on volatiles formation in wheat bread and other bakery products. Copyright © 2015 Elsevier B.V. All rights reserved.

Real-time quantification of emissions of volatile organic compounds from land spreading of pig slurry measured by PTR-MS and wind tunnels.

PubMed

Liu, Dezhao; Nyord, Tavs; Rong, Li; Feilberg, Anders

2018-10-15

Volatile organic compounds (VOC) and hydrogen sulfide are emitted from land spreading of manure slurry to the atmosphere and contribute to odour nuisance, particle formation and tropospheric ozone formation. Data on emissions is almost non-existing partly due to lack of suitable quantitative methods for measuring emissions in full scale. Here we present a method based on application of wind tunnels for simulation of air exchange combined with the use of online mass spectrometry (PTR-MS). The focus was on odorous VOC but all relevant VOC were included. A method for quantification of VOC emission based on calculated proton-transfer reaction rate constants was validated by comparison to reference concentrations for typical VOC emitted from pig manure slurry. Wall losses of volatile sulfur compounds in the wind tunnels were assessed to be insignificant and recoveries >95% were observed for these compounds. An influence of air exchange rate was clearly observed highlighting the need to identify realistic air exchange rates for future application of the method. Emission data was obtained for spreading of pig manure slurry as an example of an important source of gases. Emissions were monitored for ~37 h following land spreading and time-resolved emission data was presented for the first time. Highest emissions were observed for short-chain volatile carboxylic acids (C 2 -C 6 ) with acetic acid being the most abundant compound. Emission peaks were observed immediately following application and were followed by declining emissions until the second day at which emissions reached a second peak for several compounds. This second emission peak was speculated to be caused by a temperature-induced diurnal effect. Emissions of volatile sulfur compounds occurred on a short time-scale and ceased shortly after application. Odour activity values were dominated by C 4 -C 5 carboxylic acids and 4-methylphenol with a less pronounced influence of 4-methylphenol on day 2. Copyright © 2018 Elsevier B.V. All rights reserved.

Analysis of factors affecting volatile compound formation in roasted pumpkin seeds with selected ion flow tube-mass spectrometry (SIFT-MS) and sensory analysis.

PubMed

Bowman, T; Barringer, S

2012-01-01

Pumpkin (Cucurbita pepo and maxima) seeds are uniquely flavored and commonly consumed as a healthy roasted snack. The objective was to determine dominant volatiles in raw and roasted pumpkin seeds, and the effect of seed coat, moisture content, fatty acid ratio, total lipids, reducing sugars, and harvest year on volatile formation. Sensory was conducted to evaluate overall liking of seed variety and texture. Seed processing included extraction from the fruit, dehydration, and roasting (150 °C). Oil extraction was done using soxhlet, fatty acid profile using Gas Chromatography Flame Ionization Detector, and reducing sugars using 3,5-dinitrosalicylic acid and UV-spectroscopy. Headspace analysis of seeds was performed by selected ion flow tube-mass spectrometry (SIFT-MS). Volatiles dominating in raw pumpkin seeds were lipid aldehydes, ethyl acetate, 2,3-butandione, and dimethylsulfide. Compounds contributing to roasted aroma include alkylpyrazines and Strecker and lipid aldehydes. Overall, hull-less seeds had higher volatile lipid aldehydes and Strecker aldehydes. Seeds dehydrated to a moisture content of 6.5% before roasting had higher initial and final volatile concentrations than seeds starting at 50% moisture. Higher oil content resulted in higher lipid aldehyde formation during roasting with a moderate correlation between free fatty acid ratio and corresponding lipid aldehyde. Harvest year (2009 compared with 2010) had a significant impact on volatile formation in hull-less seeds, but not as much as variety differences. No significant correlation was found between reducing sugars and volatile formation. Sensory showed that hull-less seeds were liked significantly more than hulled seeds. Elucidation of aromatic flavor development during roasting with SIFT-MS provides information on flavor release and offers better control during processing. Knowledge of volatiles in raw and roasted pumpkin seeds and effects of seed coat, moisture content, seed composition, and harvest date will allow for better control over the production/storage/transportation process and a more educated decision during selection of a variety for production of pumpkin seeds in the snack food industry. © 2011 Institute of Food Technologists®

Volatile compounds of Celta dry-cured 'lacón' as affected by cross-breeding with Duroc and Landrace genotypes.

PubMed

Lorenzo, José M; Fonseca, Sonia

2014-11-01

Dry-cured 'lacón' is a traditional cured meat product made in the north-west of Spain from the pigs' foreleg, with similar manufacturing process to that used in dry-cured ham. The aim of this study was to assess the influence of cross-breeding of Celta pig with Landrace or Duroc breeds on the formation of volatile compounds through the manufacture of 'lacón'. 'Lacón' from the crosses with Duroc presented lower final moisture (534 g kg(-1) ) and higher intra-muscular fat content [144 g kg(-1) dry matter (DM)] than 'lacón' from Celta pure breed (587 g kg(-1) and 36 g kg(-1) DM, respectively). Volatile compounds were extracted by solid-phase microextraction and analysed by gas chromatography-mass spectrometry. Volatile compounds from 'lacón' were affected by cross-breeding. The total amount of volatile compounds significantly (P < 0.001) increased during the manufacturing process, this increase being more marked in samples from the Landrace cross-breed. The most abundant group of flavour compounds at the end of the manufacturing process was esters in the three batches, followed by aldehydes, hydrocarbons and alcohols. The most abundant ester at the end of the process was hexanoic acid methyl ester, while the aldehyde found in a higher amount was hexanal. The profile of volatile compounds was affected by cross-breed, especially at the end of the 'lacón' dry-curing process. © 2014 Society of Chemical Industry.

Secondary organic aerosol production from pinanediol, a semi-volatile surrogate for first-generation oxidation products of monoterpenes

NASA Astrophysics Data System (ADS)

Ye, Penglin; Zhao, Yunliang; Chuang, Wayne K.; Robinson, Allen L.; Donahue, Neil M.

2018-05-01

We have investigated the production of secondary organic aerosol (SOA) from pinanediol (PD), a precursor chosen as a semi-volatile surrogate for first-generation oxidation products of monoterpenes. Observations at the CLOUD facility at CERN have shown that oxidation of organic compounds such as PD can be an important contributor to new-particle formation. Here we focus on SOA mass yields and chemical composition from PD photo-oxidation in the CMU smog chamber. To determine the SOA mass yields from this semi-volatile precursor, we had to address partitioning of both the PD and its oxidation products to the chamber walls. After correcting for these losses, we found OA loading dependent SOA mass yields from PD oxidation that ranged between 0.1 and 0.9 for SOA concentrations between 0.02 and 20 µg m-3, these mass yields are 2-3 times larger than typical of much more volatile monoterpenes. The average carbon oxidation state measured with an aerosol mass spectrometer was around -0.7. We modeled the chamber data using a dynamical two-dimensional volatility basis set and found that a significant fraction of the SOA comprises low-volatility organic compounds that could drive new-particle formation and growth, which is consistent with the CLOUD observations.

Can forest trees compensate for stress-generated growth losses by induced production of volatile compounds?

PubMed

Holopainen, Jarmo K

2011-12-01

Plants produce a variety of volatile organic compounds (VOCs). Under abiotic and biotic stresses, the number and amount of produced compounds can increase. Due to their long life span and large size, trees can produce biogenic VOCs (BVOCs) in much higher amounts than many other plants. It has been suggested that at cellular and tree physiological levels, induced production of VOCs is aimed at improving plant resistance to damage by reactive oxygen species generated by multiple abiotic stresses. In the few reported cases when biosynthesis of plant volatiles is inhibited or enhanced, the observed response to stress can be attributed to plant volatiles. Reported increase, e.g., in photosynthesis has mostly ranged between 5 and 50%. A comprehensive model to explain similar induction of VOCs under multiple biotic stresses is not yet available. As a result of pathogen or herbivore attack on forest trees, the induced production of VOCs is localized to the damage site but systemic induction of emissions has also been detected. These volatiles can affect fungal pathogens and the arrival rate of herbivorous insects on damaged trees, but also act as signalling compounds to maintain the trophic cascades that may improve tree fitness by improved efficiency of herbivore natural enemies. On the forest scale, biotic induction of VOC synthesis and release leads to an amplified flow of BVOCs in atmospheric reactions, which in atmospheres rich in oxides of nitrogen (NOx) results in ozone formation, and in low NOx atmospheres results in oxidation of VOCs, removal in ozone from the troposphere and the resulting formation of biogenic secondary organic aerosol (SOA) particles. I will summarize recent advances in the understanding of stress-induced VOC emissions from trees, with special focus on Populus spp. Particular importance is given to the ecological and atmospheric feedback systems based on BVOCs and biogenic SOA formation.

Deodorization of garlic breath volatiles by food and food components.

PubMed

Munch, Ryan; Barringer, Sheryl A

2014-04-01

The ability of foods and beverages to reduce allyl methyl disulfide, diallyl disulfide, allyl mercaptan, and allyl methyl sulfide on human breath after consumption of raw garlic was examined. The treatments were consumed immediately following raw garlic consumption for breath measurements, or were blended with garlic prior to headspace measurements. Measurements were done using a selected ion flow tube-mass spectrometer. Chlorophyllin treatment demonstrated no deodorization in comparison to the control. Successful treatments may be due to enzymatic, polyphenolic, or acid deodorization. Enzymatic deodorization involved oxidation of polyphenolic compounds by enzymes, with the oxidized polyphenols causing deodorization. This was the probable mechanism in raw apple, parsley, spinach, and mint treatments. Polyphenolic deodorization involved deodorization by polyphenolic compounds without enzymatic activity. This probably occurred for microwaved apple, green tea, and lemon juice treatments. When pH is below 3.6, the enzyme alliinase is inactivated, which causes a reduction in volatile formation. This was demonstrated in pH-adjusted headspace measurements. However, the mechanism for volatile reduction on human breath (after volatile formation) is unclear, and may have occurred in soft drink and lemon juice breath treatments. Whey protein was not an effective garlic breath deodorant and had no enzymatic activity, polyphenolic compounds, or acidity. Headspace concentrations did not correlate well to breath treatments. © 2014 Institute of Food Technologists®

Induction of trap formation in nematode-trapping fungi by bacteria-released ammonia.

PubMed

Su, H N; Xu, Y Y; Wang, X; Zhang, K Q; Li, G H

2016-04-01

A total of 11 bacterial strains were assayed for bacteria-induced trap formation in the nematode-trapping fungus Arthrobotrys oligospora YMF1·01883 with two-compartmented Petri dish. These strains were identified on the basis of their 16S rRNA gene sequences. Volatile organic compounds (VOCs) of eight isolates were extracted using solid-phase micro-extraction (SPME) and their structures were identified based on gas chromatography-mass spectrometry (GC-MS). At the same time, all isolates were used for quantitative measurement of ammonia by the indophenol blue method. The effects of pure commercial compounds on inducement of trap formation in A. oligospora were tested. Taken together, results demonstrated that the predominant bacterial volatile compound inducing trap formation was ammonia. Meanwhile, ammonia also played a role in other nematode-trapping fungi, including Arthrobotrys guizhouensis YMF1·00014, producing adhesive nets; Dactylellina phymatopaga YMF1·01474, producing adhesive knobs; Dactylellina cionopaga YMF1·01472, producing adhesive columns and Drechslerella brochopaga YMF1·01829, producing constricting rings. © 2016 The Society for Applied Microbiology.

Characterization of Volatile Flavor Compounds in Chinese Rice Wine Fermented from Enzymatic Extruded Rice.

PubMed

Xu, Enbo; Long, Jie; Wu, Zhengzong; Li, Hongyan; Wang, Fang; Xu, Xueming; Jin, Zhengyu; Jiao, Aiquan

2015-07-01

Enzymatic extrusion, instead of traditional steam cooking, to treat rice is an efficient and alternative pretreatment for Chinese rice wine fermentation. In order to determine the formation of volatiles in enzymatic extrusion-processed rice wine (EE), and to confirm its characteristic flavor compounds, headspace solid-phase micro-extraction followed by GC-MS was used. A total of 66 volatile compounds were identified in EE. During fermentation, most volatiles generated from enzymatic extruded rice had the similar trends with those from steam-cooked rice, but the differences in the concentration of volatiles indicated a changed balance of flavors release caused by enzymatic extrusion. Besides, the concentrations and sorts of volatiles in EEs fermented from different rice particle sizes, were not dramatically different. By principal component analysis, EE could be distinctly separated from other traditional Chinese rice wines according to its characteristic volatiles, namely, 2-heptanol, 1-octen-3-ol, ethyl 4-hydroxybenzoate, methylpentyl 2-propenoate, γ-hexalactone, and 4-vinylguaiacol. Enzymatic extrusion liquefaction has been a popular thermal treatment for cereals, and gradually being applied in fermentation and liquor-making industry all over the world. The characterization of volatile flavor compounds in Chinese rice wine processed by enzymatic extrusion liquefaction pretreatment, might be made use not only for a better understanding of this new-type rice wine, but for the further utilization of enzymatic extrusion in other wine or alcohol production as well. © 2015 Institute of Food Technologists®

Looking into individual coffee beans during the roasting process: direct micro-probe sampling on-line photo-ionisation mass spectrometric analysis of coffee roasting gases.

PubMed

Hertz-Schünemann, Romy; Streibel, Thorsten; Ehlert, Sven; Zimmermann, Ralf

2013-09-01

A micro-probe (μ-probe) gas sampling device for on-line analysis of gases evolving in confined, small objects by single-photon ionisation time-of-flight mass spectrometry (SPI-TOFMS) was developed. The technique is applied for the first time in a feasibility study to record the formation of volatile and flavour compounds during the roasting process within (inside) or in the direct vicinity (outside) of individual coffee beans. A real-time on-line analysis of evolving volatile and semi-volatile organic compounds (VOC and SVOC) as they are formed under the mild pyrolytic conditions of the roasting process was performed. The soft-ionisation mass spectra depict a molecular ion signature, which is well corresponding with the existing knowledge of coffee roasting and evolving compounds. Additionally, thereby it is possible to discriminate between Coffea arabica (Arabica) and Coffea canephora (Robusta). The recognized differences in the roasting gas profiles reflect the differences in the precursor composition of the coffee cultivars very well. Furthermore, a well-known set of marker compounds for Arabica and Robusta, namely the lipids kahweol and cafestol (detected in their dehydrated form at m/z 296 and m/z 298, respectively) were observed. If the variation in time of different compounds is observed, distinctly different evolution behaviours were detected. Here, phenol (m/z 94) and caffeine (m/z 194) are exemplary chosen, whereas phenol shows very sharp emission peaks, caffeine do not have this highly transient behaviour. Finally, the changes of the chemical signature as a function of the roasting time, the influence of sampling position (inside, outside) and cultivar (Arabica, Robusta) is investigated by multivariate statistics (PCA). In summary, this pilot study demonstrates the high potential of the measurement technique to enhance the fundamental knowledge of the formation processes of volatile and semi-volatile flavour compounds inside the individual coffee bean.

Influence of volatile organic compounds emitted by Pseudomonas and Serratia strains on Agrobacterium tumefaciens biofilms.

PubMed

Plyuta, Vladimir; Lipasova, Valentina; Popova, Alexandra; Koksharova, Olga; Kuznetsov, Alexander; Szegedi, Erno; Chernin, Leonid; Khmel, Inessa

2016-07-01

The ability to form biofilms plays an important role in bacteria-host interactions, including plant pathogenicity. In this work, we investigated the action of volatile organic compounds (VOCs) produced by rhizospheric strains of Pseudomonas chlororaphis 449, Pseudomonas fluorescens B-4117, Serratia plymuthica IC1270, as well as Serratia proteamaculans strain 94, isolated from spoiled meat, on biofilms formation by three strains of Agrobacterium tumefaciens which are causative agents of crown-gall disease in a wide range of plants. In dual culture assays, the pool of volatiles emitted by the tested Pseudomonas and Serratia strains suppressed the formation of biofilms of A. tumefaciens strains grown on polycarbonate membrane filters and killed Agrobacterium cells in mature biofilms. The individual VOCs produced by the tested Pseudomonas strains, that is, ketones (2-nonanone, 2-heptanone, 2-undecanone), and dimethyl disulfide (DMDS) produced by Serratia strains, were shown to kill A. tumefaciens cells in mature biofilms and suppress their formation. The data obtained in this study suggest an additional potential of some ketones and DMDS as protectors of plants against A. tumefaciens strains, whose virulence is associated with the formation of biofilms on the infected plants. © 2016 APMIS. Published by John Wiley & Sons Ltd.

Secondary organic aerosol formation and composition from the photo-oxidation of methyl chavicol (estragole)

NASA Astrophysics Data System (ADS)

Pereira, K. L.; Hamilton, J. F.; Rickard, A. R.; Bloss, W. J.; Alam, M. S.; Camredon, M.; Muñoz, A.; Vázquez, M.; Borrás, E.; Ródenas, M.

2014-06-01

The increasing demand for palm oil for uses in biofuel and food products is leading to rapid expansion of oil palm agriculture. Methyl chavicol (also known as estragole and 1-allyl-4-methoxybenzene) is an oxygenated biogenic volatile organic compound (VOC) that was recently identified as the main floral emission from an oil palm plantation in Malaysian Borneo. The emissions of methyl chavicol observed may impact regional atmospheric chemistry, but little is known of its ability to form secondary organic aerosol (SOA). The photo-oxidation of methyl chavicol was investigated at the European Photoreactor chamber as a part of the atmospheric chemistry of methyl chavicol (ATMECH) project. Aerosol samples were collected using a particle into liquid sampler (PILS) and analysed offline using an extensive range of instruments including; high-performance liquid chromatography mass spectrometry (HPLC-ITMS), high-performance liquid chromatography quadrupole time-of-flight mass spectrometry (HPLC-QTOFMS) and Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). The SOA yield was determined as 18 and 29% for an initial VOC mixing ratio of 212 and 460 ppbv (parts per billion by volume) respectively; using a VOC:NOx ratio of ~5:1. In total, 59 SOA compounds were observed and the structures of 10 compounds have been identified using high-resolution tandem mass spectrometry. The addition of hydroxyl and/or nitro-functional groups to the aromatic ring appears to be an important mechanistic pathway for aerosol formation. This results in the formation of compounds with both low volatility and high O:C ratios, where functionalisation rather than fragmentation is mainly observed as a result of the stability of the ring. The SOA species observed can be characterised as semi-volatile to low-volatility oxygenated organic aerosol (SVOOA and LVOOA) components and therefore may be important in aerosol formation and growth.

Biological Treatment of Water Disinfection Byproducts using Biotrickling Filter under Anaerobic Conditions

EPA Science Inventory

Presentation not available. Abstract provided. The chlorination of potable water leads to the formation of harmful disinfection byproducts (DBPs) such as trihalomethanes (THMs) and haloacetic acids (HAAs). Many of these compounds are volatile organic compounds (VOCs). DBPs may ...

Influence of Aerosol Acidity on the Formation of Secondary Organic Aerosol from Biogenic Precursor Hydrocarbons

EPA Science Inventory

Secondary organic aerosol (SOA) formation and dynamics may be important factors for the role of aerosols in adverse health effects, visibility and climate change. Formation of SOA occurs when a parent volatile organic compound is oxidized to create products that form in a conden...

Modeling the formation and properties of traditional and non-traditional secondary organic aerosol: problem formulation and application to aircraft exhaust

NASA Astrophysics Data System (ADS)

Jathar, S. H.; Miracolo, M. A.; Presto, A. A.; Adams, P. J.; Robinson, A. L.

2012-04-01

We present a methodology to model secondary organic aerosol (SOA) formation from the photo-oxidation of low-volatility organics (semi-volatile and intermediate volatility organic compounds). The model is parameterized and tested using SOA data collected during two field campaigns that characterized the atmospheric evolution of dilute gas-turbine engine emissions using a smog chamber. Photo-oxidation formed a significant amount of SOA, much of which cannot be explained based on the emissions of traditional, speciated precursors; we refer to this as non-traditional SOA (NT-SOA). The NT-SOA can be explained by emissions of low-volatility organic vapors measured using sorbents. Since these vapors could not be speciated, we employ a volatility-based approach to model NT-SOA formation. We show that the method proposed by Robinson et al. (2007) is unable to explain the timing of NT-SOA formation because it assumes a very modest reduction in volatility of the precursors with every oxidation reaction. In contrast, a Hybrid method, similar to models of traditional SOA formation, assumes a larger reduction in volatility with each oxidation step and results in a better reproduction of NT-SOA formation. The NT-SOA yields estimated for the low-volatility organic vapor emissions are similar to literature data for large n-alkanes and other low-volatility organics. The yields vary with fuel composition (JP8 versus Fischer-Tropsch) and engine load (idle versus non-idle). These differences are consistent with the expected contribution of high (aromatics and n-alkanes) and low (branched alkanes and oxygenated species) SOA forming species to the exhaust.

Catalytic pyrolysis of wheat bran for hydrocarbons production in the presence of zeolites and noble-metals by using TGA-FTIR method.

PubMed

Lazdovica, K; Liepina, L; Kampars, V

2016-05-01

Pyrolysis of wheat bran with or without catalysts was investigated using TGA-FTIR method in order to determine the influence of zeolite and noble metal catalysts on the evolution profile and relative yield of the volatile compounds. The addition of all catalysts decreased the volatile matter of wheat bran from 76.3% to 75.9%, 73.9%, 73.5%, 69.7% and increased the solid residue from 18.0% to 18.4%, 20.4%, 20.8%, 24.6% under the catalyst of ZSM-5, 5% Pd/C, MCM-41, and 5% Pt/C. Noble-metal catalysts had higher activity for deoxygenation of compounds containing carbonyl, carboxyl, and hydroxyl groups than zeolites. Degradation of nitrogen containing compounds atom proceeded better in presence of zeolites. Noble-metal catalysts promoted formation of aromatics and changed the profiles of evolved compounds whereas zeolites advanced formation of aliphatics and olefins. Copyright © 2016 Elsevier Ltd. All rights reserved.

Molecular characterization of nitrogen and sulfur containing compounds in night-time SOA

NASA Astrophysics Data System (ADS)

Iinuma, Yoshiteru; Mutzel, Anke; Rodigast, Maria; Böge, Olaf; Herrmann, Hartmut

2014-05-01

The oxidation of volatile organic compounds (VOCs) leads to the formation of low volatile organic compounds that can form secondary organic aerosol (SOA). Studies in the past showed that laboratory generated and ambient SOA are made of polar molecules with O/C ratios generally greater than 0.5. More recent studies have shown that SOA compounds can contain heteroatoms mainly sulfur and nitrogen atoms. Offline chemical analysis with high-resolution mass spectrometers and fragmentation experiments has shown that sulphur containing compounds are mainly organosulfates and nitrogen containing species are aromatic heterocyclic compounds such as imidazole and nitrated aromatic compounds such as nitrophenols. In addition to these, SOA compounds containing both sulfur and nitrogen have been reported from the analysis of ambient organic aerosol, rainwater, fog and cloud samples. Based on the mass spectrometric evidence these compounds are attributed to nitrooxy-organosulfates originating from isoprene and monoterpenes. Although these compounds are ubiquitously detected in the ambient samples, reports about their detection in laboratory generated SOA are scares and their formation mechanisms are not well understood. In the present study, we investigated the formation of sulfur and nitrogen containing SOA species in the oxidation of biogenic VOCs. Photooxidation and night-time oxidation experiments were performed in a smog chamber to produce SOA samples. The laboratory generated SOA samples were analysed with UPLC-IMS-TOFMS (Ultra Performance Liquid Chromatography coupled to Ion Mobility Spectrometry and Time of Flight Mass Spectrometry). The presence of highly acidic sulphate seed particles (pH0) did not promote the formation of compounds with chemical formula of C10H17NO7S- and m/z value of 294.0653, indicating that the formation mechanisms of these compounds unlikely involve the ring opening reactions of epoxides and subsequent sulfation reactions. On the other hand, their formation was significantly enhanced when the night-time oxidation was performed in the presence of both neutral seed particle and gas-phase SO2, suggesting that the presence of gas-phase SO2 is a key for their formation.

Partitioning Behavior of Organic Contaminants in Carbon Storage Environments: A Critical Review

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burant, Aniela; Lowry, Gregory V; Karamalidis, Athanasios K

2012-12-04

Carbon capture and storage is a promising strategy for mitigating the CO{sub 2} contribution to global climate change. The large scale implementation of the technology mandates better understanding of the risks associated with CO{sub 2} injection into geologic formations and the subsequent interactions with groundwater resources. The injected supercritical CO{sub 2} (sc-CO{sub 2}) is a nonpolar solvent that can potentially mobilize organic compounds that exist at residual saturation in the formation. Here, we review the partitioning behavior of selected organic compounds typically found in depleted oil reservoirs in the residual oil–brine–sc-CO{sub 2} system under carbon storage conditions. The solubility ofmore » pure phase organic compounds in sc-CO{sub 2} and partitioning of organic compounds between water and sc-CO{sub 2} follow trends predicted based on thermodynamics. Compounds with high volatility and low aqueous solubility have the highest potential to partition to sc-CO{sub 2}. The partitioning of low volatility compounds to sc-CO{sub 2} can be enhanced by co-solvency due to the presence of higher volatility compounds in the sc-CO{sub 2}. The effect of temperature, pressure, salinity, pH, and dissolution of water molecules into sc-CO{sub 2} on the partitioning behavior of organic compounds in the residual oil-brine-sc-CO{sub 2} system is discussed. Data gaps and research needs for models to predict the partitioning of organic compounds in brines and from complex mixtures of oils are presented. Models need to be able to better incorporate the effect of salinity and co-solvency, which will require more experimental data from key classes of organic compounds.« less

Identification and characterization of terpene synthases potentially involved in the formation of volatile terpenes in carrot (Daucus carota L.) roots

USDA-ARS?s Scientific Manuscript database

Plants produce numerous volatile organic compounds, which are important in determining the quality and nutraceutical properties of fruit and root crops, including the taste and the aroma of carrots (Daucus carota L.). A combined chemical, biochemical and molecular study was conducted to evaluate the...

Effect of persistent trace compounds in landfill gas on engine performance during energy recovery: a case study.

PubMed

Sevimoğlu, Orhan; Tansel, Berrin

2013-01-01

Performances of gas engines operated with landfill gas (LFG) are affected by the impurities in the LFG, reducing the economic viability of energy recovery. The purpose of this study was to characterize the trace compounds in the LFG at the Odayeri Landfill, Istanbul, Turkey which is used for energy recovery. Composite gas samples were collected and analyzed for trace compounds (hydrocarbons, siloxanes, and volatile halogenated hydrocarbons) over a 3-year period. Trace compounds entering the gas engines, their impact on the engine performance were evaluated. The operational problems included deposit formation in the combustion chamber, turbocharger, and intercooler of engine before the scheduled maintenance times. High levels of hydrogen sulfide, as well as chlorinated and fluorinated compounds cause corrosion of the engine parts and decrease life of the engine oils. Persistence of siloxanes results in deposit formation, increasing engine maintenance costs. Pretreatment of LFG is necessary to protect the engines at the waste-to-energy facilities with persistence levels of siloxanes and volatile halogenated hydrocarbons. Copyright © 2012 Elsevier Ltd. All rights reserved.

Monitoring of Yeast Communities and Volatile Flavor Changes During Traditional Korean Soy Sauce Fermentation.

PubMed

Song, Young-Ran; Jeong, Do-Youn; Baik, Sang-Ho

2015-09-01

Flavor development in soy sauce is significantly related to the diversity of yeast species. Due to its unique fermentation with meju, the process of making Korean soy sauce gives rise to a specific yeast community and, therefore, flavor profile; however, no detailed analysis of the identifying these structure has been performed. Changes in yeast community structure during Korean soy sauce fermentation were examined using both culture-dependent and culture-independent methods with simultaneous analysis of the changes in volatile compounds by GC-MS analysis. During fermentation, Candida, Pichia, and Rhodotorula sp. were the dominant species, whereas Debaryomyces, Torulaspora, and Zygosaccharomyces sp. were detected only at the early stage. In addition, Cryptococcus, Microbotryum, Tetrapisispora, and Wickerhamomyces were detected as minor strains. Among the 62 compounds identified in this study, alcohols, ketones, and pyrazines were present as the major groups during the initial stages, whereas the abundance of acids with aldehydes increased as the fermentation progressed. Finally, the impacts of 10 different yeast strains found to participate in fermentation on the formation of volatile compounds were evaluated under soy-based conditions. It was revealed that specific species produced different profiles of volatile compounds, some of which were significant flavor contributors, especially volatile alcohols, aldehydes, esters, and ketones. © 2015 Institute of Food Technologists®

Function of bacterial community dynamics in the formation of cadaveric semiochemicals during in situ carcass decomposition.

PubMed

Pascual, Javier; von Hoermann, Christian; Rottler-Hoermann, Ann-Marie; Nevo, Omer; Geppert, Alicia; Sikorski, Johannes; Huber, Katharina J; Steiger, Sandra; Ayasse, Manfred; Overmann, Jörg

2017-08-01

The decomposition of dead mammalian tissue involves a complex temporal succession of epinecrotic bacteria. Microbial activity may release different cadaveric volatile organic compounds which in turn attract other key players of carcass decomposition such as scavenger insects. To elucidate the dynamics and potential functions of epinecrotic bacteria on carcasses, we monitored bacterial communities developing on still-born piglets incubated in different forest ecosystems by combining high-throughput Illumina 16S rRNA sequencing with gas chromatography-mass spectrometry of volatiles. Our results show that the community structure of epinecrotic bacteria and the types of cadaveric volatile compounds released over the time course of decomposition are driven by deterministic rather than stochastic processes. Individual cadaveric volatile organic compounds were correlated with specific taxa during the first stages of decomposition which are dominated by bacteria. Through best-fitting multiple linear regression models, the synthesis of acetic acid, indole and phenol could be linked to the activity of Enterobacteriaceae, Tissierellaceae and Xanthomonadaceae, respectively. These conclusions are also commensurate with the metabolism described for the dominant taxa identified for these families. The predictable nature of in situ synthesis of cadaveric volatile organic compounds by epinecrotic bacteria provides a new basis for future chemical ecology and forensic studies. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

Multidimensional analysis of cannabis volatile constituents: identification of 5,5-dimethyl-1-vinylbicyclo[2.1.1]hexane as a volatile marker of hashish, the resin of Cannabis sativa L.

PubMed

Marchini, Marie; Charvoz, Céline; Dujourdy, Laurence; Baldovini, Nicolas; Filippi, Jean-Jacques

2014-11-28

The volatile constituents of drug samples derived from Cannabis sativa L. were investigated by means of headspace solid phase microextraction (HS-SPME) and gas chromatography techniques (GC-MS, GC×GC-MS). Samples of cannabis herb and hashish showed clear differences in their volatile chemical profiles, mostly resulting from photo-oxidation processes occurring during the transformation of fresh cannabis herb into hashish. Most unexpectedly, we could demonstrate hashish samples as containing remarkable amounts of a rare and unusual monoterpene - 5,5-dimethyl-1-vinylbicyclo[2.1.1]hexane - among the volatile compounds detected in their headspaces. We gave evidence for the formation of this compound from the light induced rearrangement of β-myrcene during the manufacture of hashish. In view of its high abundance among volatile constituents of cannabis resin and its scarce occurrence in other natural volatile extracts, we propose to rename this specific monoterpene hashishene. Copyright © 2014 Elsevier B.V. All rights reserved.

Modeling study of secondary organic aerosol in winter in China using NAQPMS

NASA Astrophysics Data System (ADS)

Yang, W.; Li, J.

2017-12-01

The concentration of organic aerosol (OA) in the central and eastern China is much higher than that in Europe and America. Compared with the observation, the current numerical modeling studies largely underestimated the concentration of OA, especially the secondary component. Based on the volatility basis set framework, a secondary organic aerosol (SOA) module was developed, which considering the multi-generation oxidation of volatile organic compounds (VOCs), semi-volatile POA and intermediate volatility organic compounds (IVOCs). The newly developed SOA module was coupled into the NAQPMS, and the performance of the simulation was validated by the observation with high temporal resolution. In wintertime, the OA concentration in the central and eastern China was maintained above 15-20 μg·m-3, and SOA accounted for 50-65% of OA concentration. The OA concentration even reached 40 μg·m-3 in the provinces emitting most pollutants (such as Hunan, Hubei, Henan, Anhui, Jiangsu, Shandong and Hubei province). IVOCs were important precursors of SOA in China, and could reduce the great discrepancy between simulation and observation. In wintertime, the contribution from IVOCs accounted for 60-80% of SOA formation. The aging of semi-volatile POA had less impact on the SOA formation, which maintained only 2-8% over central and eastern China.

Isotopic analyses of nitrogenous compounds from the Murchison meteorite: ammonia, amines, amino acids, and polar hydrocarbons

NASA Technical Reports Server (NTRS)

Pizzarello, S.; Feng, X.; Epstein, S.; Cronin, J. R.

1994-01-01

The combined volatile bases (ammonia, aliphatic amines, and possibly other bases), ammonia, amino acids, and polar hydrocarbons were prepared from the Murchison meteorite for isotopic analyses. The volatile bases were obtained by cryogenic transfer after acid-hydrolysis of a hot-water extract and analyzed by combined gas chromatography-mass spectrometry of pentafluoropropionyl derivatives. The aliphatic amines present in this preparation comprise a mixture that includes both primary and secondary isomers through C5 at a total concentration of > or = 100 nmoles g-1. As commonly observed for meteoritic organic compounds, almost all isomers through C5 are present, and the concentrations within homologous series decrease with increasing chain length. Ammonia was chromatographically separated from the other volatile bases and found at a concentration of 1.1-1.3 micromoles g-1 meteorite. The ammonia analyzed includes contributions from ammonium salts and the hydrolysis of extractable organic compounds, e.g., carboxamides. Stable isotope analyses showed the volatile bases to be substantially enriched in the heavier isotopes, relative to comparable terrestrial compounds delta D < or = +1221%; delta 13C = +22%; delta 15N = +93%). Ammonia, per se, was found to have a somewhat lower delta 15N value (+69%) than the total volatile bases; consequently, a higher delta 15N (>93%) can be inferred for the other bases, which include the amines. Solvent-extractable polar hydrocarbons obtained separately were found to be enriched in 15N (delta 15N = +104%). Total amino acids, prepared from a hydrolyzed hot-water extract by cation exchange chromatography, gave a delta 15N of +94%, a value in good agreement with that obtained previously. Nitrogen isotopic data are also given for amino acid fractions separated chromatographically. The delta 15N values of the Murchison soluble organic compounds analyzed to date fall within a rather narrow range (delta 15N = +94 +/- 8%), an observation consistent with their formation, or formation of their precursors, by interstellar chemistry.

Two Herbivore-Induced Cytochrome P450 Enzymes CYP79D6 and CYP79D7 Catalyze the Formation of Volatile Aldoximes Involved in Poplar Defense[C][W

PubMed Central

Irmisch, Sandra; Clavijo McCormick, Andrea; Boeckler, G. Andreas; Schmidt, Axel; Reichelt, Michael; Schneider, Bernd; Block, Katja; Schnitzler, Jörg-Peter; Gershenzon, Jonathan; Unsicker, Sybille B.; Köllner, Tobias G.

2013-01-01

Aldoximes are known as floral and vegetative plant volatiles but also as biosynthetic intermediates for other plant defense compounds. While the cytochrome P450 monooxygenases (CYP) from the CYP79 family forming aldoximes as biosynthetic intermediates have been intensively studied, little is known about the enzymology of volatile aldoxime formation. We characterized two P450 enzymes, CYP79D6v3 and CYP79D7v2, which are involved in herbivore-induced aldoxime formation in western balsam poplar (Populus trichocarpa). Heterologous expression in Saccharomyces cerevisiae revealed that both enzymes produce a mixture of different aldoximes. Knockdown lines of CYP79D6/7 in gray poplar (Populus × canescens) exhibited a decreased emission of aldoximes, nitriles, and alcohols, emphasizing that the CYP79s catalyze the first step in the formation of a complex volatile blend. Aldoxime emission was found to be restricted to herbivore-damaged leaves and is closely correlated with CYP79D6 and CYP79D7 gene expression. The semi-volatile phenylacetaldoxime decreased survival and weight gain of gypsy moth (Lymantria dispar) caterpillars, suggesting that aldoximes may be involved in direct defense. The wide distribution of volatile aldoximes throughout the plant kingdom and the presence of CYP79 genes in all sequenced genomes of angiosperms suggest that volatile formation mediated by CYP79s is a general phenomenon in the plant kingdom. PMID:24220631

Heating-Induced Evaporation of Nine Different Secondary Organic Aerosol Types

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kolesar, Katheryn R.; Li, Ziyue; Wilson, Kevin R.

The volatility of the compounds comprising organic aerosol (OA) determines their distribution between the gas and particle phases. However, there is a disconnect between volatility distributions as typically derived from secondary OA (SOA) growth experiments and the effective particle volatility as probed in evaporation experiments. Specifically, the evaporation experiments indicate an overall much less volatile SOA. This raises questions regarding the use of traditional volatility distributions in the simulation and prediction of atmospheric SOA concentrations. Here, we present results from measurements of thermally induced evaporation of SOA for nine different SOA types (i.e., distinct volatile organic compound and oxidant pairs)more » encompassing both anthropogenic and biogenic compounds and O 3 and OH to examine the extent to which the low effective volatility of SOA is a general phenomenon or specific to a subset of SOA types. The observed extents of evaporation with temperature were similar for all the SOA types and indicative of a low effective volatility. Furthermore, minimal variations in the composition of all the SOA types upon heating-induced evaporation were observed. These results suggest that oligomer decomposition likely plays a major role in controlling SOA evaporation, and since the SOA formation time scale in these measurements was less than a minute, the oligomer-forming reactions must be similarly rapid. Overall, these results emphasize the importance of accounting for the role of condensed phase reactions in altering the composition of SOA when assessing particle volatility.« less

Heating-Induced Evaporation of Nine Different Secondary Organic Aerosol Types

DOE PAGES

Kolesar, Katheryn R.; Li, Ziyue; Wilson, Kevin R.; ...

2015-09-22

The volatility of the compounds comprising organic aerosol (OA) determines their distribution between the gas and particle phases. However, there is a disconnect between volatility distributions as typically derived from secondary OA (SOA) growth experiments and the effective particle volatility as probed in evaporation experiments. Specifically, the evaporation experiments indicate an overall much less volatile SOA. This raises questions regarding the use of traditional volatility distributions in the simulation and prediction of atmospheric SOA concentrations. Here, we present results from measurements of thermally induced evaporation of SOA for nine different SOA types (i.e., distinct volatile organic compound and oxidant pairs)more » encompassing both anthropogenic and biogenic compounds and O 3 and OH to examine the extent to which the low effective volatility of SOA is a general phenomenon or specific to a subset of SOA types. The observed extents of evaporation with temperature were similar for all the SOA types and indicative of a low effective volatility. Furthermore, minimal variations in the composition of all the SOA types upon heating-induced evaporation were observed. These results suggest that oligomer decomposition likely plays a major role in controlling SOA evaporation, and since the SOA formation time scale in these measurements was less than a minute, the oligomer-forming reactions must be similarly rapid. Overall, these results emphasize the importance of accounting for the role of condensed phase reactions in altering the composition of SOA when assessing particle volatility.« less

Accurate Treatment of Collisions and Water-Delivery in Models of Terrestrial Planet Formation

NASA Astrophysics Data System (ADS)

Haghighipour, Nader; Maindl, Thomas; Schaefer, Christoph

2017-10-01

It is widely accepted that collisions among solid bodies, ignited by their interactions with planetary embryos is the key process in the formation of terrestrial planets and transport of volatiles and chemical compounds to their accretion zones. Unfortunately, due to computational complexities, these collisions are often treated in a rudimentary way. Impacts are considered to be perfectly inelastic and volatiles are considered to be fully transferred from one object to the other. This perfect-merging assumption has profound effects on the mass and composition of final planetary bodies as it grossly overestimates the masses of these objects and the amounts of volatiles and chemical elements transferred to them. It also entirely neglects collisional-loss of volatiles (e.g., water) and draws an unrealistic connection between these properties and the chemical structure of the protoplanetary disk (i.e., the location of their original carriers). We have developed a new and comprehensive methodology to simulate growth of embryos to planetary bodies where we use a combination of SPH and N-body codes to accurately model collisions as well as the transport/transfer of chemical compounds. Our methodology accounts for the loss of volatiles (e.g., ice sublimation) during the orbital evolution of their careers and accurately tracks their transfer from one body to another. Results of our simulations show that traditional N-body modeling of terrestrial planet formation overestimates the amount of the mass and water contents of the final planets by over 60% implying that not only the amount of water they suggest is far from being realistic, small planets such as Mars can also form in these simulations when collisions are treated properly. We will present details of our methodology and discuss its implications for terrestrial planet formation and water delivery to Earth.

Natural and Anthropogenically Perturbed Biogenic Aerosol over Tropical South East Asia

NASA Astrophysics Data System (ADS)

Coe, H.; Robinson, N.; Allan, J. D.; Hewitt, C. N.

2014-12-01

Tropical forested regions are of interest as sources of atmospheric aerosol since they cover very large areas of the tropics and are a source of a large amount of volatile organic compounds which act as precursors for particle formation. Natural forest regions offer the potential to study the background state of the tropics and so potentially gain some insight into the pre-perturbed atmosphere. However, over the last decade in South East Asia, a considerable fraction of the native tropical deciduous forest has been deforested and replanted with palm oil plantations. This changes the range of volatile organic compounds that are emitted and act as sources of secondary organic aerosol. A suite of intensive ground and airborne measurements were made over both tropical forest and oil palm plantations in Sabah, Malaysia as part of the "Oxidant and Particle Photochemical Processes above a South East Asian tropical rainforest (OP3) during 2008. These data will be used together with recent improvements in our understanding of aerosol formation from biogenic compounds to discuss aerosol formation in tropical regions and the influence of human influence through widespread palm oil agriculture.

Modeling the formation and properties of traditional and non-traditional secondary organic aerosol: problem formulation and application to aircraft exhaust

NASA Astrophysics Data System (ADS)

Jathar, S. H.; Miracolo, M. A.; Presto, A. A.; Donahue, N. M.; Adams, P. J.; Robinson, A. L.

2012-10-01

We present a methodology to model secondary organic aerosol (SOA) formation from the photo-oxidation of unspeciated low-volatility organics (semi-volatile and intermediate volatile organic compounds) emitted by combustion systems. It is formulated using the volatility basis-set approach. Unspeciated low-volatility organics are classified by volatility and then allowed to react with the hydroxyl radical. The new methodology allows for larger reductions in volatility with each oxidation step than previous volatility basis set models, which is more consistent with the addition of common functional groups and similar to those used by traditional SOA models. The methodology is illustrated using data collected during two field campaigns that characterized the atmospheric evolution of dilute gas-turbine engine emissions using a smog chamber. In those experiments, photo-oxidation formed a significant amount of SOA, much of which could not be explained based on the emissions of traditional speciated precursors; we refer to the unexplained SOA as non-traditional SOA (NT-SOA). The NT-SOA can be explained by emissions of unspeciated low-volatility organics measured using sorbents. We show that the parameterization proposed by Robinson et al. (2007) is unable to explain the timing of the NT-SOA formation in the aircraft experiments because it assumes a very modest reduction in volatility of the precursors with every oxidation reaction. In contrast the new method better reproduces the NT-SOA formation. The NT-SOA yields estimated for the unspeciated low-volatility organic emissions in aircraft exhaust are similar to literature data for large n-alkanes and other low-volatility organics. The estimated yields vary with fuel composition (Jet Propellent-8 versus Fischer-Tropsch) and engine load (ground idle versus non-ground idle). The framework developed here is suitable for modeling SOA formation from emissions from other combustion systems.

Effects of 4 Probiotic Strains in Coculture with Traditional Starters on the Flavor Profile of Yogurt.

PubMed

Tian, Huaixiang; Shen, Yongbo; Yu, Haiyan; He, Yujie; Chen, Chen

2017-07-01

To study the influence of probiotics on the flavor profile of yogurt, 4 probiotics, including Lactobacillus acidophilus, Lactobacillus plantarum, Lactobacillus rhamnosus, and Lactobacillus casei, were cofermented with traditional starters. The changes of bacterial growth, acid contents and volatile compounds of yogurt were investigated during fermentation and refrigerated storage. The strains that exhibited a low growth rate in milk did not significantly affect the bacterial population dynamics, acidity, or organic acid content during fermentation and storage. However, high viability and enhancement of postacidification were clearly observed in the samples that contained strains with a high growth rate in milk, particularly L. casei. A total of 45 volatile compounds, detected in most samples, were identified by headspace solid-phase micro-extraction followed by gas chromatography-mass spectrometry. Among these compounds, ketones and aldehydes were the most abundant. The presence of either L. rhamnosus or L. plantarum did not significantly affect the major volatile compounds, while contributions of L. casei and L. acidophilus were found in the formation of minor volatile metabolites. Electronic nose measurements exhibited a good discrimination of samples that contained different probiotics during refrigerated storage. © 2017 Institute of Food Technologists®.

The effects of diet and breed on the volatile compounds of cooked lamb.

PubMed

Elmore, J S; Mottram, D S; Enser, M; Wood, J D

2000-06-01

The effect of varying the n-3 polyunsaturated fatty acid (PUFA) composition of lamb muscle on the formation of aroma volatiles during cooking has been examined. The meat was obtained from four groups of Suffolk and Soay lambs fed different supplementary fats: a palm-oil based control; bruised whole linseed, which increased muscle levels of α-linolenic acid (C18:3 n-3); fish oil, which increased eicosapentaenoic acid (EPA, C20:5 n-3) and docosahexaenoic acid (DHA, C22:6 n-3); and equal quantities of linseed and fish oil (fat basis). Higher quantities of lipid oxidation products were found in the aroma volatiles of lamb muscle from animals fed fish oil, compared to the control. In particular, unsaturated aldehydes, unsaturated hydrocarbons and alkylfurans increased up to fourfold. These compounds derived from the autoxidation of PUFAs during cooking. Although some of these volatiles were increased in meat from animals fed the linseed supplement, the effect was not as great as with the fish oil fed lambs. Levels of volatiles derived from the Maillard reaction, such as pyrazines and sulfur compounds, were up to four times higher in Soays than Suffolks.

Predominant yeasts in Chinese traditional sourdough and their influence on aroma formation in Chinese steamed bread.

PubMed

Liu, Tongjie; Li, Yang; Sadiq, Faizan A; Yang, Huanyi; Gu, Jingsi; Yuan, Lei; Lee, Yuan Kun; He, Guoqing

2018-03-01

A total of 105 yeast isolates was obtained from 15 sourdough samples collected from different regions in China and subjected to random amplified polymorphic DNA (RAPD) analysis. Six species were identified including Pichia membranifaciens, which has not previously been reported in Chinese sourdoughs. Different species of yeast were used in single-culture fermentation to make Chinese steamed bread (CSB). The volatiles of the CSB were captured by solid-phase microextraction method, separated and identified by gas chromatography-mass spectrometry. In total, 41 volatile compounds were found in all the steamed breads. All CSBs showed a similar volatile profile; however, significant differences in the quantity of some volatile compounds were seen among the CSB fermented by different yeast species. A partial least squares discriminant analysis showed that the CSBs could be separated by their characteristic volatile profiles. The study suggested that the aromatic properties of CSB are determined by the yeast used. Copyright © 2017 Elsevier Ltd. All rights reserved.

Observing BVOC Emissions, Oxidation, Deposition, and Interactions with Anthropogenic Pollutants to Form SOA in the Southeast United States

NASA Astrophysics Data System (ADS)

Goldstein, A. H.; Isaacman, G. A.; Misztal, P. K.; Yee, L.; Olson, K. F.; Moss, J.; Kreisberg, N. M.; Hering, S. V.; Park, J. H.; Kaser, L.; Seco, R.; Guenther, A. B.; Su, L.; Mak, J. E.; Holzinger, R.; Hu, W.; Campuzano Jost, P.; Palm, B. B.; Day, D. A.; Jimenez, J. L.; Koss, A.; De Gouw, J. A.

2014-12-01

Our overarching goals in the SOAS 2013 campaign were to 1) quantify biogenic VOC emission and VOC deposition to understand the processes controlling these bi-directional exchanges, 2) observe a broad suite of primary VOC and their oxidation products in the field and in controlled laboratory experiments, and 3) investigate their fate to understand how anthropogenic pollution alters oxidation pathways and secondary organic aerosol (SOA) formation. We pursued these goals through measurement of atmospheric organics ranging from very volatile (using in-situ GC-MS and proton transfer reaction time-of-flight MS, PTR-ToF-MS) to semi-volatile gas and particle phase compounds (using the Semi-Volatile Thermal desorption Aerosol Gas chromatograph, SV-TAG). Measured concentrations and fluxes of VOCs at the top of the SEARCH tower were coordinated with concentration gradients and fluxes at the AABC flux tower site, and vertical profiles using the Long-EZ aircraft to provide equivalent observations across sites. These results are informed through measurements using the same instrument during the FIXIT controlled laboratory oxidation study at CalTech that investigated oxidation pathways of BVOC with varying levels of anthropogenic pollutants. Measurements by SV-TAG of particle-phase and total gas-plus-particle-phase compounds at the SEARCH tower provide hourly quantification of semi-volatile compounds, including the oxidation products of measured VOCs. Derivatization of hydroxyl groups prior to GC analysis allows analysis of highly oxidized chemicals, including most known tracers. Methyl tetrols, an oxidation product of isoprene, had a significant day-time gas-phase component, and their abundance was strongly correlated with particle-phase sulfate, indicative of anthropogenic influence on the formation or partitioning processes. Similar observations of pinic acid (monterpene oxidation product) and many other BVOC oxidation products were made in both the gas and particle phases. Through measurements of specific chemical tracers across a wide range of volatilities, we explore the chemical lifecycle of BVOCs to understand anthropogenic-biogenic interactions in aerosol formation.

Volatile compounds of sulfur in the Fe-C-S system at 5.3 GPa and 1300°C

NASA Astrophysics Data System (ADS)

Zhimulev, E. I.; Sonin, V. M.; Bul'bak, T. A.; Chepurov, A. I.; Tomilenko, A. A.; Pokhilenko, N. P.

2015-05-01

This report presents the results of experimental studies of the fluid phase in the Fe-C-S system at high P and T values (5.3 GPa and 1300°C) conforming to diamond synthesis. The samples for experiments were mounted on air; therefore, the volatile compounds detected after the experiments are characterized by a wide variety and complicated composition involving both inorganic and organic components. Among the inorganic compounds, CO2, H2O, N2, SO2, CS2, and COS were detected. The GC/MS analysis revealed hydrocarbons (paraffins, olefins, and arenes), including high-molecular compounds. The formation of heavy hydrocarbons confirms their thermodynamic stability under high pressure. Oxygenated hydrocarbons (alcohols, aldehydes, ketones, carboxylic acids, and ethers) were also detected.

Quantifying Volatile Organic Compound Emissions from Solvents and their Impacts on Urban Air Quality

NASA Astrophysics Data System (ADS)

Mcdonald, B. C.; De Gouw, J. A.; Gilman, J.; Ahmadov, R.; Cappa, C. D.; Frost, G. J.; Goldstein, A. H.; Jathar, S.; Jimenez, J. L.; Kim, S. W.; McKeen, S. A.; Roberts, J. M.; Trainer, M.

2016-12-01

Solvents, which consist of personal care products, paints, degreasing agents, and other chemical products, are an important anthropogenic source of volatile organic compound (VOC) emissions. Yet there are many unresolved questions related to their emission rates, chemical composition, and relative importance on urban air quality problems. Using atmospheric measurements of speciated VOCs collected at a ground site located in the Los Angeles basin during the California Nexus (CalNex) Study in 2010, and utilizing data on the composition of solvent emissions from the California Air Resources Board (CARB), we are able to reconcile solvent emissions with ambient observations. Our analysis indicates that solvent emissions are underestimated by a factor of 2-3 in the CARB inventory. We then estimate the reactivity of solvent emissions with the hydroxyl (OH) radical, and also estimate the propensity of solvent emissions to form secondary organic aerosol (SOA). Solvents contain significant fractions of oxygenated compounds, including intermediate volatility compounds, which if released to the atmosphere are potentially reactive and can lead to the formation of SOA. Overall, our results suggest that in the Los Angeles basin, solvents are now the largest anthropogenic source of VOC emissions, OH reactivity, and SOA formation, and larger than the contribution from motor vehicles. This suggests that more research is needed in better constraining this potentially important source of urban VOC emissions.

The Impact of Single Amino Acids on Growth and Volatile Aroma Production by Saccharomyces cerevisiae Strains

PubMed Central

Fairbairn, Samantha; McKinnon, Alexander; Musarurwa, Hannibal T.; Ferreira, António C.; Bauer, Florian F.

2017-01-01

Nitrogen availability and utilization by Saccharomyces cerevisiae significantly influence fermentation kinetics and the production of volatile compounds important for wine aroma. Amino acids are the most important nitrogen source and have been classified based on how well they support growth. This study evaluated the effect of single amino acids on growth kinetics and major volatile production of two phenotypically different commercial wine yeast strains in synthetic grape must. Four growth parameters, lag phase, maximum growth rate, total biomass formation and time to complete fermentation were evaluated. In contrast with previous findings, in fermentative conditions, phenylalanine and valine supported growth well and asparagine supported it poorly. The four parameters showed good correlations for most amino acid treatments, with some notable exceptions. Single amino acid treatments resulted in the predictable production of aromatic compounds, with a linear correlation between amino acid concentration and the concentration of aromatic compounds that are directly derived from these amino acids. With the increased complexity of nitrogen sources, linear correlations were lost and aroma production became unpredictable. However, even in complex medium minor changes in amino acid concentration continued to directly impact the formation of aromatic compounds, suggesting that the relative concentration of individual amino acids remains a predictor of aromatic outputs, independently of the complexity of metabolic interactions between carbon and nitrogen metabolism and between amino acid degradation and utilization pathways. PMID:29312237

The Impact of Single Amino Acids on Growth and Volatile Aroma Production by Saccharomyces cerevisiae Strains.

PubMed

Fairbairn, Samantha; McKinnon, Alexander; Musarurwa, Hannibal T; Ferreira, António C; Bauer, Florian F

2017-01-01

Nitrogen availability and utilization by Saccharomyces cerevisiae significantly influence fermentation kinetics and the production of volatile compounds important for wine aroma. Amino acids are the most important nitrogen source and have been classified based on how well they support growth. This study evaluated the effect of single amino acids on growth kinetics and major volatile production of two phenotypically different commercial wine yeast strains in synthetic grape must. Four growth parameters, lag phase, maximum growth rate, total biomass formation and time to complete fermentation were evaluated. In contrast with previous findings, in fermentative conditions, phenylalanine and valine supported growth well and asparagine supported it poorly. The four parameters showed good correlations for most amino acid treatments, with some notable exceptions. Single amino acid treatments resulted in the predictable production of aromatic compounds, with a linear correlation between amino acid concentration and the concentration of aromatic compounds that are directly derived from these amino acids. With the increased complexity of nitrogen sources, linear correlations were lost and aroma production became unpredictable. However, even in complex medium minor changes in amino acid concentration continued to directly impact the formation of aromatic compounds, suggesting that the relative concentration of individual amino acids remains a predictor of aromatic outputs, independently of the complexity of metabolic interactions between carbon and nitrogen metabolism and between amino acid degradation and utilization pathways.

Characterization of volatiles and identification of odor-active compounds of rocket leaves.

PubMed

Raffo, Antonio; Masci, Maurizio; Moneta, Elisabetta; Nicoli, Stefano; Sánchez Del Pulgar, José; Paoletti, Flavio

2018-02-01

The volatile profile of crushed rocket leaves (Eruca sativa and Diplotaxis tenuifolia) was investigated by applying Headspace Solid-Phase MicroExtraction (HS-SPME), combined with GC-MS, to an aqueous extract obtained by homogenization of rocket leaves, and stabilized by addition of CaCl 2 . A detailed picture of volatile products of the lipoxygenase pathway (mainly C6-aldehydes) and of glucosinolate hydrolysis (mainly isothiocyanates), and their dynamics of formation after tissue disruption was given. Odor-active compounds of leaves were characterized by GC-Olfactometry (GC-O) and Aroma Extract Dilution Analysis (AEDA): volatile isolates obtained by HS-SPME from an aqueous extract and by Stir-Bar Sorptive Extraction (SBSE) from an ethanolic extract were analyzed. The most potent odor-active compounds fully or tentatively identified were (Z)- and (E)-3-hexenal, (Z)-1,5-octadien-3-one, responsible for green olfactory notes, along with 4-mercaptobutyl and 4-(methylthio)butyl isothiocyanate, associated with typical rocket and radish aroma. Relatively high odor potency was observed for 1-octen-3-one, (E)-2-octenal and 1-penten-3-one. Copyright © 2017 Elsevier Ltd. All rights reserved.

75 FR 57390 - Approval and Promulgation of Implementation Plans; Alabama: Volatile Organic Compounds

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-21

... Tropospheric ozone, commonly known as smog, occurs when VOCs and nitrogen oxides (NO X ) react in the... contribution to tropospheric ozone formation. EPA is approving revisions to the Alabama SIP submitted on March... the VOC definition on the basis that these compounds make a negligible contribution to tropospheric...

Production of extremely low volatile organic compounds from biogenic emissions: Measured yields and atmospheric implications

PubMed Central

Jokinen, Tuija; Berndt, Torsten; Makkonen, Risto; Kerminen, Veli-Matti; Junninen, Heikki; Stratmann, Frank; Herrmann, Hartmut; Guenther, Alex B.; Worsnop, Douglas R.; Kulmala, Markku; Ehn, Mikael; Sipilä, Mikko

2015-01-01

Oxidation products of monoterpenes and isoprene have a major influence on the global secondary organic aerosol (SOA) burden and the production of atmospheric nanoparticles and cloud condensation nuclei (CCN). Here, we investigate the formation of extremely low volatility organic compounds (ELVOC) from O3 and OH radical oxidation of several monoterpenes and isoprene in a series of laboratory experiments. We show that ELVOC from all precursors are formed within the first minute after the initial attack of an oxidant. We demonstrate that under atmospherically relevant concentrations, species with an endocyclic double bond efficiently produce ELVOC from ozonolysis, whereas the yields from OH radical-initiated reactions are smaller. If the double bond is exocyclic or the compound itself is acyclic, ozonolysis produces less ELVOC and the role of the OH radical-initiated ELVOC formation is increased. Isoprene oxidation produces marginal quantities of ELVOC regardless of the oxidant. Implementing our laboratory findings into a global modeling framework shows that biogenic SOA formation in general, and ELVOC in particular, play crucial roles in atmospheric CCN production. Monoterpene oxidation products enhance atmospheric new particle formation and growth in most continental regions, thereby increasing CCN concentrations, especially at high values of cloud supersaturation. Isoprene-derived SOA tends to suppress atmospheric new particle formation, yet it assists the growth of sub-CCN-size primary particles to CCN. Taking into account compound specific monoterpene emissions has a moderate effect on the modeled global CCN budget. PMID:26015574

Production of extremely low volatile organic compounds from biogenic emissions: Measured yields and atmospheric implications.

PubMed

Jokinen, Tuija; Berndt, Torsten; Makkonen, Risto; Kerminen, Veli-Matti; Junninen, Heikki; Paasonen, Pauli; Stratmann, Frank; Herrmann, Hartmut; Guenther, Alex B; Worsnop, Douglas R; Kulmala, Markku; Ehn, Mikael; Sipilä, Mikko

2015-06-09

Oxidation products of monoterpenes and isoprene have a major influence on the global secondary organic aerosol (SOA) burden and the production of atmospheric nanoparticles and cloud condensation nuclei (CCN). Here, we investigate the formation of extremely low volatility organic compounds (ELVOC) from O3 and OH radical oxidation of several monoterpenes and isoprene in a series of laboratory experiments. We show that ELVOC from all precursors are formed within the first minute after the initial attack of an oxidant. We demonstrate that under atmospherically relevant concentrations, species with an endocyclic double bond efficiently produce ELVOC from ozonolysis, whereas the yields from OH radical-initiated reactions are smaller. If the double bond is exocyclic or the compound itself is acyclic, ozonolysis produces less ELVOC and the role of the OH radical-initiated ELVOC formation is increased. Isoprene oxidation produces marginal quantities of ELVOC regardless of the oxidant. Implementing our laboratory findings into a global modeling framework shows that biogenic SOA formation in general, and ELVOC in particular, play crucial roles in atmospheric CCN production. Monoterpene oxidation products enhance atmospheric new particle formation and growth in most continental regions, thereby increasing CCN concentrations, especially at high values of cloud supersaturation. Isoprene-derived SOA tends to suppress atmospheric new particle formation, yet it assists the growth of sub-CCN-size primary particles to CCN. Taking into account compound specific monoterpene emissions has a moderate effect on the modeled global CCN budget.

Formation of volatile sulfur compounds and metabolism of methionine and other sulfur compounds in fermented food.

PubMed

Landaud, Sophie; Helinck, Sandra; Bonnarme, Pascal

2008-01-01

The formation of volatile sulfur compounds (VSC) in fermented food is a subject of interest. Such compounds are essential for the aroma of many food products like cheeses or fermented beverages, in which they can play an attractive or a repulsive role, depending on their identity and their concentration. VSC essentially arise from common sulfur-bearing precursors, methionine being the most commonly found. In the first section of this paper, the main VSC found in cheese, wine, and beer are reviewed. It is shown that a wide variety of VSC has been evidenced in these food products. Because of their low odor threshold and flavor notes, these compounds impart essential sensorial properties to the final product. In the second section of this review, the main (bio)chemical pathways leading to VSC synthesis are presented. Attention is focused on the microbial/enzymatic phenomena-which initiate sulfur bearing precursors degradation-leading to VSC production. Although chemical reactions could also play an important role in this process, this aspect is not fully developed in our review. The main catabolic pathways leading to VSC from the precursor methionine are presented.

Nitrogen-Containing Low Volatile Compounds from Pinonaldehyde-Dimethylamine Reaction in the Atmosphere: A Laboratory and Field Study.

PubMed

Duporté, Geoffroy; Parshintsev, Jevgeni; Barreira, Luís M F; Hartonen, Kari; Kulmala, Markku; Riekkola, Marja-Liisa

2016-05-03

Pinonaldehyde, which is among the most abundant oxidation products of α-pinene, and dimethylamine were selected to study the formation of N-containing low volatile compounds from aldehyde-amine reactions in the atmosphere. Gas phase reactions took place in a Tedlar bag, which was connected to a mass spectrometer ionization source via a short deactivated fused silica column. In addition to on-line analysis, abundance of gaseous precursors and reaction products were monitored off-line. Condensable products were extracted from the bag's walls with a suitable solvent and analyzed by gas chromatography coupled to chemical ionization high-resolution quadrupole time-of-flight mass spectrometry and by ultra-high-performance liquid chromatography coupled to electrospray ionization Orbitrap mass spectrometry. The reactions carried out resulted in several mid-low vapor pressure nitrogen-containing compounds that are potentially important for the formation of secondary organic aerosols in the atmosphere. Further, the presence of brown carbon, confirmed by liquid chromatography-UV-vis-mass spectrometry, was observed. Some of the compounds identified in the laboratory study were also observed in aerosol samples collected at SMEAR II station (Hyytiälä, Finland) in August 2015 suggesting the importance of aldehyde-amine reactions for the aerosol formation and growth.

Volatile organic compound constituents from an integrated iron and steel facility.

PubMed

Tsai, Jiun-Horng; Lin, Kuo-Hsiung; Chen, Chih-Yu; Lai, Nina; Ma, Sen-Yi; Chiang, Hung-Lung

2008-09-15

This study measured the volatile organic compound (VOC) constituents of four processes in an integrated iron and steel industry; cokemaking, sintering, hot forming, and cold forming. Toluene, 1,2,4-trimethylbenzene, isopentane, m,p-xylene, 1-butene, ethylbenzene, and benzene were the predominant VOC species in these processes. However, some of the chlorinated compounds were high (hundreds ppbv), i.e., trichloroethylene in all four processes, carbon tetrachloride in the hot forming process, chlorobenzene in the cold forming process, and bromomethane in the sintering process. In the sintering process, the emission factors of toluene, benzene, xylene, isopentane, 1,2,4-trimethylbenzene, and ethylbenzene were over 9 g/tonne-product. In the vicinity of the manufacturing plant, toluene, isopentane, 1,2,4-trimethylbenzene, xylene and ethylbenzene were high. Toluene, 1,2,4-trimethylbenzene, xylene, 1-butene and isopentane were the major ozone formation species. Aromatic compounds were the predominant VOC groups, constituting 45-70% of the VOC concentration and contributing >70% to the high ozone formation potential in the stack exhaust and workplace air. The sequence of VOC concentration and ozone formation potential was as follows: cold forming>sintering>hot forming>cokemaking. For the workplace air, cokemaking was the highest producer, which was attributed to the fugitive emissions of the coke oven and working process release.

Late-stage magmatic outgassing from a volatile-depleted Moon

PubMed Central

Moynier, Frédéric; Shearer, Charles K.

2017-01-01

The abundance of volatile elements and compounds, such as zinc, potassium, chlorine, and water, provide key evidence for how Earth and the Moon formed and evolved. Currently, evidence exists for a Moon depleted in volatile elements, as well as reservoirs within the Moon with volatile abundances like Earth’s depleted upper mantle. Volatile depletion is consistent with catastrophic formation, such as a giant impact, whereas a Moon with Earth-like volatile abundances suggests preservation of these volatiles, or addition through late accretion. We show, using the “Rusty Rock” impact melt breccia, 66095, that volatile enrichment on the lunar surface occurred through vapor condensation. Isotopically light Zn (δ66Zn = −13.7‰), heavy Cl (δ37Cl = +15‰), and high U/Pb supports the origin of condensates from a volatile-poor internal source formed during thermomagmatic evolution of the Moon, with long-term depletion in incompatible Cl and Pb, and lesser depletion of more-compatible Zn. Leaching experiments on mare basalt 14053 demonstrate that isotopically light Zn condensates also occur on some mare basalts after their crystallization, confirming a volatile-depleted lunar interior source with homogeneous δ66Zn ≈ +1.4‰. Our results show that much of the lunar interior must be significantly depleted in volatile elements and compounds and that volatile-rich rocks on the lunar surface formed through vapor condensation. Volatiles detected by remote sensing on the surface of the Moon likely have a partially condensate origin from its interior. PMID:28827322

Late-stage magmatic outgassing from a volatile-depleted Moon.

PubMed

Day, James M D; Moynier, Frédéric; Shearer, Charles K

2017-09-05

The abundance of volatile elements and compounds, such as zinc, potassium, chlorine, and water, provide key evidence for how Earth and the Moon formed and evolved. Currently, evidence exists for a Moon depleted in volatile elements, as well as reservoirs within the Moon with volatile abundances like Earth's depleted upper mantle. Volatile depletion is consistent with catastrophic formation, such as a giant impact, whereas a Moon with Earth-like volatile abundances suggests preservation of these volatiles, or addition through late accretion. We show, using the "Rusty Rock" impact melt breccia, 66095, that volatile enrichment on the lunar surface occurred through vapor condensation. Isotopically light Zn (δ 66 Zn = -13.7‰), heavy Cl (δ 37 Cl = +15‰), and high U/Pb supports the origin of condensates from a volatile-poor internal source formed during thermomagmatic evolution of the Moon, with long-term depletion in incompatible Cl and Pb, and lesser depletion of more-compatible Zn. Leaching experiments on mare basalt 14053 demonstrate that isotopically light Zn condensates also occur on some mare basalts after their crystallization, confirming a volatile-depleted lunar interior source with homogeneous δ 66 Zn ≈ +1.4‰. Our results show that much of the lunar interior must be significantly depleted in volatile elements and compounds and that volatile-rich rocks on the lunar surface formed through vapor condensation. Volatiles detected by remote sensing on the surface of the Moon likely have a partially condensate origin from its interior.

Late-stage magmatic outgassing from a volatile-depleted Moon

NASA Astrophysics Data System (ADS)

Day, James M. D.; Moynier, Frédéric; Shearer, Charles K.

2017-09-01

The abundance of volatile elements and compounds, such as zinc, potassium, chlorine, and water, provide key evidence for how Earth and the Moon formed and evolved. Currently, evidence exists for a Moon depleted in volatile elements, as well as reservoirs within the Moon with volatile abundances like Earth’s depleted upper mantle. Volatile depletion is consistent with catastrophic formation, such as a giant impact, whereas a Moon with Earth-like volatile abundances suggests preservation of these volatiles, or addition through late accretion. We show, using the “Rusty Rock” impact melt breccia, 66095, that volatile enrichment on the lunar surface occurred through vapor condensation. Isotopically light Zn (δ66Zn = -13.7‰), heavy Cl (δ37Cl = +15‰), and high U/Pb supports the origin of condensates from a volatile-poor internal source formed during thermomagmatic evolution of the Moon, with long-term depletion in incompatible Cl and Pb, and lesser depletion of more-compatible Zn. Leaching experiments on mare basalt 14053 demonstrate that isotopically light Zn condensates also occur on some mare basalts after their crystallization, confirming a volatile-depleted lunar interior source with homogeneous δ66Zn ≈ +1.4‰. Our results show that much of the lunar interior must be significantly depleted in volatile elements and compounds and that volatile-rich rocks on the lunar surface formed through vapor condensation. Volatiles detected by remote sensing on the surface of the Moon likely have a partially condensate origin from its interior.

Studies on the Effect of Sub-zero Temperatures on the Formation of Extremely Low Volatility Dimer Esters in Secondary Organic Aerosol from Alpha-Pinene

NASA Astrophysics Data System (ADS)

Kristensen, Kasper; Normann Jensen, Louise; Bilde, Merete

2016-04-01

The oxidation of volatile organic compounds (VOC) is considered a major source of secondary organic aerosols (SOA) in the atmosphere. Recently, extremely low volatility organic compounds, or ELVOC, formed from the oxidation of VOCs have been shown to play a crucial role in new particle formation (Ehn et al., 2014). In addition, higher molecular weight dimer esters originating from the oxidation of the biogenic VOC alpha-pinene have been observed in both laboratory-generated and ambient SOA (Kristensen et al., 2013). The low volatility of the dimer esters along with an observed rapid formation makes these high molecular weight compounds likely candidates involved in new particle formation from the oxidation of alpha-pinene. Furthermore, laboratory experiments show that the dimer esters only form in the presence of ozone, thus may be used as tracers for the ozone-initiated oxidation of alpha-pinene, and are therefore indicative of enhanced anthropogenic activities. In this work, we present the results of a series of oxidation experiments performed in the newly constructed cold-room smog chamber at Aarhus University. This unique and state-of-the-art Teflon chamber allows for atmospheric simulations of the oxidation VOCs and subsequent SOA formation at temperatures down to -16 °C. In this study, ozonolysis and photochemical oxidations of alpha-pinene are performed at temperatures ranging from +20 to -16 °C. Chemical characterization of the formed SOA is performed using liquid chromatography coupled to quadrupole time-of-flight mass spectrometry. The results show significant differences in the chemical composition related to the experiment temperature. In particularly, the concentration of the high molecular weight dimer esters showed to be highly affected by temperature. Interestingly, preliminary results show higher formation of dimer esters related to increased SOA formation rate, thus indicating that these particle-phase ELVOCs may be linked with new particle formation. Ehn, M., Thornton, J. A., Kleist, E., Sipila, M., Junninen, H., Pullinen, I., Springer, M., Rubach, F., Tillmann, R., Lee, B., Lopez-Hilfiker, F., Andres, S., Acir, I. H., Rissanen, M., Jokinen, T., Schobesberger, S., Kangasluoma, J., Kontkanen, J., Nieminen, T., Kurten, T., Nielsen, L. B., Jorgensen, S., Kjaergaard, H. G., Canagaratna, M., Dal Maso, M., Berndt, T., Petaja, T., Wahner, A., Kerminen, V. M., Kulmala, M., Worsnop, D. R., Wildt, J., and Mentel, T. F.: A large source of low-volatility secondary organic aerosol, Nature, 506, 476-+, 10.1038/nature13032, 2014. Kristensen, K., Enggrob, K. L., King, S. M., Worton, D. R., Platt, S. M., Mortensen, R., Rosenoern, T., Surratt, J. D., Bilde, M., Goldstein, A. H., and Glasius, M.: Formation and occurrence of dimer esters of pinene oxidation products in atmospheric aerosols, Atmospheric Chemistry and Physics, 13, 3763-3776, 2013.

Molecular structure impacts on secondary organic aerosol formation from glycol ethers

NASA Astrophysics Data System (ADS)

Li, Lijie; Cocker, David R.

2018-05-01

Glycol ethers, a class of widely used solvents in consumer products, are often considered exempt as volatile organic compounds based on their vapor pressure or boiling points by regulatory agencies. However, recent studies found that glycol ethers volatilize at ambient conditions nearly as rapidly as the traditional high-volatility solvents indicating the potential of glycol ethers to form secondary organic aerosol (SOA). This is the first work on SOA formation from glycol ethers. The impact of molecular structure, specifically -OH, on SOA formation from glycol ethers and related ethers are investigated in the work. Ethers with and without -OH, with methyl group hindrance on -OH and with -OH at different location are studied in the presence of NOX and under "NOX free" conditions. Photooxidation experiments under different oxidation conditions confirm that the processing of ethers is a combination of carbonyl formation, cyclization and fragmentation. Bulk SOA chemical composition analysis and oxidation products identified in both gas and particle phase suggests that the presence and location of -OH in the carbon bond of ethers determine the occurrence of cyclization mechanism during ether oxidation. The cyclization is proposed as a critical SOA formation mechanism to prevent the formation of volatile compounds from fragmentation during the oxidation of ethers. Glycol ethers with -CH2-O-CH2CH2OH structure is found to readily form cyclization products, especially with the presence of NOx, which is more relevant to urban atmospheric conditions than without NOx. Glycol ethers are evaluated as dominating SOA precursors among all ethers studied. It is estimated that the contribution of glycol ethers to anthropogenic SOA is roughly 1% of the current organic aerosol from mobile sources. The contribution of glycol ethers to anthropogenic SOA is roughly 1% of the current organic aerosol from mobile sources and will play a more important role in future anthropogenic SOA formation.

Kinetic analysis of volatile formation in milk subjected to pressure-assisted thermal treatments.

PubMed

Vazquez-Landaverde, P A; Qian, M C; Torres, J A

2007-09-01

Volatile formation in milk subjected to pressure-assisted thermal processing (PATP) was investigated from a reaction kinetic analysis point of view to illustrate the advantages of this technology. The concentration of 27 volatiles of different chemical class in milk subjected to pressure, temperature, and time treatments was fitted to zero-, 1st-, and 2nd-order chemical reaction models. Temperature and pressure effects on rate constants were analyzed to obtain activation energy (E(a)) and activation volume (deltaV*) values. Hexanal, heptanal, octanal, nonanal, and decanal followed 1st-order kinetics with rate constants characterized by E(a) values decreasing with pressure reflecting negative deltaV* values. Formation of 2-methylpropanal, 2,3-butanedione, and hydrogen sulfide followed zero-order kinetics with rate constants increasing with temperature but with unclear pressure effects. E(a) values for 2-methylpropanal and 2,3-butanedione increased with pressure, that is, deltaV* > 0, whereas values for hydrogen sulfide remained constant, that is, deltaV* = 0. The concentration of all other volatiles, including methanethiol, remained unchanged in pressure-treated samples, suggesting large negative deltaV* values. The concentration of methyl ketones, including 2-pentanone, 2-hexanone, 2-heptanone, 2-octanone, 2-nonanone, 2-decanone, and 2-undecanone, was independent of pressure and pressure-holding time. PATP promoted the formation of few compounds, had no effect on some, and inhibited the formation of volatiles reported to be factors of the consumer rejection of "cooked" milk flavor. The kinetic behavior observed suggested that new reaction formation mechanisms were not likely involved in volatile formation in PATP milk. The application of the Le Chatelier principle frequently used to explain the high quality of pressure-treated foods, often with no supporting experimental evidence, was not necessary.

Things fall apart: Fragmentation reactions in the oxidative aging of organic species

NASA Astrophysics Data System (ADS)

Kroll, J. H.; Isaacman-VanWertz, G. A.; Wilson, K. R.; Daumit, K. E.; Kessler, S. H.; Lim, C. Y.; Worsnop, D. R.

2016-12-01

The atmospheric oxidation of organic compounds involves a wide array of chemical transformations, including functionalization reactions (addition of polar functional groups to the carbon skeleton), fragmentation reactions (formation of lower carbon-number products via C-C bond scission), and accretion reactions (increases in molecular weight by the combination of two chemical species). Each of these reaction classes can lead to large changes in volatility, and hence can have major implications for atmospheric organic aerosol (OA). For example, the formation of OA is predominantly driven by functionalization and accretion reactions, which generally lead to decreases in volatility. Here we describe a series of laboratory studies of the subsequent organic "aging", the multiday oxidation processes that occur after the initial OA formation and growth. In these studies, the multigenerational oxidation of organic compounds in various phases (the gas phase, the condensed OA phase, and the aqueous phase) is carried out within either an environmental chamber or a flow reactor, and monitored using various high-resolution mass spectrometric techniques. In all cases it is found that fragmentation reactions play a major role in the observed aging chemistry, dominated by the formation of small, volatile oxidation products. These results suggest that multi-day oxidative aging processes do not lead to sustained aerosol growth, but rather may serve as a chemical sink for atmospheric OA.

Missing ozone-induced potential aerosol formation in a suburban deciduous forest

NASA Astrophysics Data System (ADS)

Nakayama, T.; Kuruma, Y.; Matsumi, Y.; Morino, Y.; Sato, K.; Tsurumaru, H.; Ramasamy, S.; Sakamoto, Y.; Kato, S.; Miyazaki, Y.; Mochizuki, T.; Kawamura, K.; Sadanaga, Y.; Nakashima, Y.; Matsuda, K.; Kajii, Y.

2017-12-01

As a new approach to investigating formation processes of secondary organic aerosol (SOA) in the atmosphere, ozone-induced potential aerosol formation was measured in summer at a suburban forest site surrounded by deciduous trees, near Tokyo, Japan. After passage through a reactor containing high concentrations of ozone, increases in total particle volume (average of 1.4 × 109 nm3/cm3, which corresponds to 17% that of pre-existing particles) were observed, especially during daytime. The observed aerosol formations were compared with the results of box model simulations using simultaneously measured concentrations of gaseous and particulate species. According to the model, the relative contributions of isoprene, monoterpene, and aromatic hydrocarbon oxidation to SOA formation in the reactor were 24, 21, and 55%, respectively. However, the model could explain, on average, only ∼40% of the observed particle formation, and large discrepancies between the observations and model were found, especially around noon and in the afternoon when the concentrations of isoprene and oxygenated volatile organic compounds were high. The results suggest a significant contribution of missing (unaccounted-for) SOA formation processes from identified and/or unidentified volatile organic compounds, especially those emitted during daytime. Further efforts should be made to explore and parameterize this missing SOA formation to assist in the improvement of atmospheric chemistry and climate models.

The reduction of HNO3 by volatile organic compounds emitted by motor vehicles

NASA Astrophysics Data System (ADS)

Rutter, A. P.; Malloy, Q. G. J.; Leong, Y. J.; Gutierrez, C. V.; Calzada, M.; Scheuer, E.; Dibb, J. E.; Griffin, R. J.

2014-04-01

Nitric acid (HNO3) was reduced in a flow tube by volatile organic carbon compounds (VOCs) generated from engine oil vapor. The primary reaction product was believed to be HONO. The reaction was not enhanced when Teflon® Raschig rings were added to the flow tube to increase surface area, thereby showing the reaction to be homogeneous under the conditions studied. The HONO formation observed ranged between 0.1 and 0.6 ppb h-1, with a mean of 0.3 ± 0.1 ppb h-1, for typical HNO3 concentrations of 4-5 ppb and estimated concentrations of the reactive components in the engine oil vapor between 200 and 300 ppt. The observations in this study compare well to a recently published field study conducted in Houston that observed average formation rates of 0.6 ± 0.3 ppb h-1. Water vapor was found to decrease the HONO formation rate by ˜0.1 ppb h-1 for every 1% increase in the water mixing ratio.

Secondary organic aerosol formation from semi- and intermediate-volatility organic compounds and glyoxal: Relevance of O/C as a tracer for aqueous multiphase chemistry

NASA Astrophysics Data System (ADS)

Waxman, Eleanor M.; Dzepina, Katja; Ervens, Barbara; Lee-Taylor, Julia; Aumont, Bernard; Jimenez, Jose L.; Madronich, Sasha; Volkamer, Rainer

2013-03-01

The role of aqueous multiphase chemistry in the formation of secondary organic aerosol (SOA) remains difficult to quantify. We investigate it here by testing the rapid formation of moderate oxygen-to-carbon (O/C) SOA during a case study in Mexico City. A novel laboratory-based glyoxal-SOA mechanism is applied to the field data, and explains why less gas-phase glyoxal mass is observed than predicted. Furthermore, we compare an explicit gas-phase chemical mechanism for SOA formation from semi- and intermediate-volatility organic compounds (S/IVOCs) with empirical parameterizations of S/IVOC aging. The mechanism representing our current understanding of chemical kinetics of S/IVOC oxidation combined with traditional SOA sources and mixing of background SOA underestimates the observed O/C by a factor of two at noon. Inclusion of glyoxal-SOA with O/C of 1.5 brings O/C predictions within measurement uncertainty, suggesting that field observations can be reconciled on reasonable time scales using laboratory-based empirical relationships for aqueous chemistry.

Sources of ambient volatile organic compounds and their contributions to photochemical ozone formation at a site in the Pearl River Delta, southern China.

PubMed

Ling, Z H; Guo, H; Cheng, H R; Yu, Y F

2011-10-01

The Positive Matrix Factorization (PMF) receptor model and the Observation Based Model (OBM) were combined to analyze volatile organic compound (VOC) data collected at a suburban site (WQS) in the PRD region. The purposes are to estimate the VOC source apportionment and investigate the contributions of these sources and species of these sources to the O(3) formation in PRD. Ten VOC sources were identified. We further applied the PMF-extracted concentrations of these 10 sources into the OBM and found "solvent usage 1", "diesel vehicular emissions" and "biomass/biofuel burning" contributed most to the O(3) formation at WQS. Among these three sources, higher Relative Incremental Reactivity (RIR)-weighted values of ethene, toluene and m/p-xylene indicated that they were mainly responsible for local O(3) formation in the region. Sensitivity analysis revealed that the sources of "diesel vehicular emissions", "biomass/biofuel burning" and "solvent usage 1" had low uncertainties whereas "gasoline evaporation" showed the highest uncertainty. Copyright © 2011 Elsevier Ltd. All rights reserved.

Contribution of low vapor pressure-volatile organic compounds (LVP-VOCs) from consumer products to ozone formation in urban atmospheres

NASA Astrophysics Data System (ADS)

Shin, Hyeong-Moo; McKone, Thomas E.; Bennett, Deborah H.

2015-05-01

Because recent laboratory testing indicates that some low vapor pressure-volatile organic compounds (LVP-VOC) solvents readily evaporate at ambient conditions, LVP-VOCs used in some consumer product formulations may contribute to ozone formation. The goal of this study is to determine the fraction of LVP-VOCs available for ozone formation from the use of consumer products for two hypothetical emissions. This study calculates and compares the fraction of consumed product available for ozone formation as a result of (a) volatilization to air during use and (b) down-the-drain disposal. The study also investigates the impact of different modes of releases on the overall fraction available in ambient air for ozone formation. For the portion of the LVP-VOCs volatilized to air during use, we applied a multi-compartment mass-balance model to track the fate of emitted LVP-VOCs in a multimedia urban environment. For the portion of the LVP-VOCs disposed down the drain, we used a wastewater treatment plant (WWTP) fate model to predict the emission rates of LVP-VOCs to ambient air at WWTPs or at the discharge zone of the facilities and then used these results as emissions in the multimedia urban environment model. In a WWTP, the LVP-VOCs selected in this study are primarily either biodegraded or removed via sorption to sludge depending on the magnitude of the biodegradation half-life and the octanol-water partition coefficient. Less than 0.2% of the LVP-VOCs disposed down the drain are available for ozone formation. In contrast, when the LVP-VOC in a consumer product is volatilized from the surface to which it has been applied, greater than 90% is available for photochemical reactions either at the source location or in the downwind areas. Comparing results from these two modes of releases allows us to understand the importance of determining the fraction of LVP-VOCs volatilized versus disposed down the drain when the product is used by consumers. The results from this study provide important information and modeling tools to evaluate the impact of LVP-VOCs on air quality and suggest the need for future research on emissions of LVP-VOCs at the point of use.

Aroma volatility from aqueous sucrose solutions at low and subzero temperatures.

PubMed

Covarrubias-Cervantes, Marco; Champion, Dominique; Debeaufort, Frédéric; Voilley, Andrée

2004-11-17

The gas-liquid partition coefficients of ethyl acetate and ethyl hexanoate have been measured in water and aqueous sucrose solutions from 25 to -10 degrees C by dynamic headspace. Experiments were carried out on sucrose solutions at temperatures where no ice formation was possible. Results showed that when sucrose concentration increased, aroma volatility increased except for ethyl hexanoate and in the highest sucrose concentration solution (57.5%). A quasi-linear temperature decrease on aroma volatility was observed in sucrose solutions from 25 to around 4 and 0 degrees C. Then, from 0 to -10 degrees C, aroma volatility did not decrease: ethyl acetate volatility remained constant but that of ethyl hexanoate increased. Enthalpy of vaporization and activity coefficients of the aroma compounds were calculated.

In Planta Variation of Volatile Biosynthesis: An Alternative Biosynthetic Route to the Formation of the Pathogen-Induced Volatile Homoterpene DMNT via Triterpene Degradation in Arabidopsis Roots

PubMed Central

Sohrabi, Reza; Huh, Jung-Hyun; Badieyan, Somayesadat; Rakotondraibe, Liva Harinantenaina; Kliebenstein, Daniel J.; Sobrado, Pablo; Tholl, Dorothea

2015-01-01

Plant-derived volatile compounds such as terpenes exhibit substantial structural variation and serve multiple ecological functions. Despite their structural diversity, volatile terpenes are generally produced from a small number of core 5- to 20-carbon intermediates. Here, we present unexpected plasticity in volatile terpene biosynthesis by showing that irregular homo/norterpenes can arise from different biosynthetic routes in a tissue specific manner. While Arabidopsis thaliana and other angiosperms are known to produce the homoterpene (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) or its C16-analog (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene by the breakdown of sesquiterpene and diterpene tertiary alcohols in aboveground tissues, we demonstrate that Arabidopsis roots biosynthesize DMNT by the degradation of the C30 triterpene diol, arabidiol. The reaction is catalyzed by the Brassicaceae-specific cytochrome P450 monooxygenase CYP705A1 and is transiently induced in a jasmonate-dependent manner by infection with the root-rot pathogen Pythium irregulare. CYP705A1 clusters with the arabidiol synthase gene ABDS, and both genes are coexpressed constitutively in the root stele and meristematic tissue. We further provide in vitro and in vivo evidence for the role of the DMNT biosynthetic pathway in resistance against P. irregulare. Our results show biosynthetic plasticity in DMNT biosynthesis in land plants via the assembly of triterpene gene clusters and present biochemical and genetic evidence for volatile compound formation via triterpene degradation in plants. PMID:25724638

Ozone-Induced Responses in Croton floribundus Spreng. (Euphorbiaceae): Metabolic Cross-Talk between Volatile Organic Compounds and Calcium Oxalate Crystal Formation

PubMed Central

Cardoso-Gustavson, Poliana; Bolsoni, Vanessa Palermo; de Oliveira, Debora Pinheiro; Guaratini, Maria Tereza Gromboni; Aidar, Marcos Pereira Marinho; Marabesi, Mauro Alexandre; Alves, Edenise Segala; de Souza, Silvia Ribeiro

2014-01-01

Here, we proposed that volatile organic compounds (VOC), specifically methyl salicylate (MeSA), mediate the formation of calcium oxalate crystals (COC) in the defence against ozone (O3) oxidative damage. We performed experiments using Croton floribundus, a pioneer tree species that is tolerant to O3 and widely distributed in the Brazilian forest. This species constitutively produces COC. We exposed plants to a controlled fumigation experiment and assessed biochemical, physiological, and morphological parameters. O3 induced a significant increase in the concentrations of constitutive oxygenated compounds, MeSA and terpenoids as well as in COC number. Our analysis supported the hypothesis that ozone-induced VOC (mainly MeSA) regulate ROS formation in a way that promotes the opening of calcium channels and the subsequent formation of COC in a fast and stable manner to stop the consequences of the reactive oxygen species in the tissue, indeed immobilising the excess calcium (caused by acute exposition to O3) that can be dangerous to the plant. To test this hypothesis, we performed an independent experiment spraying MeSA over C. floribundus plants and observed an increase in the number of COC, indicating that this compound has a potential to directly induce their formation. Thus, the tolerance of C. floribundus to O3 oxidative stress could be a consequence of a higher capacity for the production of VOC and COC rather than the modulation of antioxidant balance. We also present some insights into constitutive morphological features that may be related to the tolerance that this species exhibits to O3. PMID:25165889

Comparison of different procedures to stabilize biogas formation after process failure in a thermophilic waste digestion system: Influence of aggregate formation on process stability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kleyboecker, A.; Liebrich, M.; Kasina, M.

2012-06-15

Highlights: Black-Right-Pointing-Pointer Mechanism of process recovery with calcium oxide. Black-Right-Pointing-Pointer Formation of insoluble calcium salts with long chain fatty acids and phosphate. Black-Right-Pointing-Pointer Adsorption of VFAs by the precipitates resulting in the formation of aggregates. Black-Right-Pointing-Pointer Acid uptake and phosphate release by the phosphate-accumulating organisms. Black-Right-Pointing-Pointer Microbial degradation of volatile fatty acids in the aggregates. - Abstract: Following a process failure in a full-scale biogas reactor, different counter measures were undertaken to stabilize the process of biogas formation, including the reduction of the organic loading rate, the addition of sodium hydroxide (NaOH), and the introduction of calcium oxide (CaO). Correspondingmore » to the results of the process recovery in the full-scale digester, laboratory experiments showed that CaO was more capable of stabilizing the process than NaOH. While both additives were able to raise the pH to a neutral milieu (pH > 7.0), the formation of aggregates was observed particularly when CaO was used as the additive. Scanning electron microscopy investigations revealed calcium phosphate compounds in the core of the aggregates. Phosphate seemed to be released by phosphorus-accumulating organisms, when volatile fatty acids accumulated. The calcium, which was charged by the CaO addition, formed insoluble salts with long chain fatty acids, and caused the precipitation of calcium phosphate compounds. These aggregates were surrounded by a white layer of carbon rich organic matter, probably consisting of volatile fatty acids. Thus, during the process recovery with CaO, the decrease in the amount of accumulated acids in the liquid phase was likely enabled by (1) the formation of insoluble calcium salts with long chain fatty acids, (2) the adsorption of volatile fatty acids by the precipitates, (3) the acid uptake by phosphorus-accumulating organisms and (4) the degradation of volatile fatty acids in the aggregates. Furthermore, this mechanism enabled a stable process performance after re-activation of biogas production. In contrast, during the counter measure with NaOH aggregate formation was only minor resulting in a rapid process failure subsequent the increase of the organic loading rate.« less

Possible complex organic compounds on Mars.

PubMed

Kobayashi, K; Sato, T; Kajishima, S; Kaneko, T; Ishikawa, Y; Saito, T

1997-01-01

It is suggested that primitive Mars had somehow similar environments as primitive Earth. If life was born on the primitive earth using organic compounds which were produced from the early Earth environment, the same types of organic compounds were also formed on primitive Mars. Such organic compounds might have been preserved on Mars still now. We are studying possible organic formation on primitive and present Mars. A gaseous mixture of CO2, CO, N2 and H2O with various mixing ratios were irradiated with high energy protons (major components of cosmic rays). Hydrogen cyanide and formaldehyde were detected among volatile products, and yellow-brown-colored water-soluble non-volatile substances were produced, which gave amino acids after acid-hydrolysis. Major part of "amino acid precursors" were not simple molecules like aminonitriles, but complex compounds which eluted earlier than free amino acids in cation-exchange HPLC. These organic compounds should be major targets in the future Mars mission. Strategy for the detection of the complex organics on Mars will be discussed.

Identification of volatile organic compounds in suburban Bangkok, Thailand and their potential for ozone formation

NASA Astrophysics Data System (ADS)

Suthawaree, Jeeranut; Tajima, Yosuke; Khunchornyakong, Alisa; Kato, Shungo; Sharp, Alice; Kajii, Yoshizumi

2012-02-01

Measurement of Volatile Organic Compound (VOC) was carried out in suburban Bangkok during July 2-8, 2008. Analysis was performed using GC-FID and GC-MS. High mixing ratios of VOCs detected during the morning and evening are most likely due to vehicular emissions. Averaged VOC mixing ratios revealed distinct difference between mixing ratios of weekdays and weekend, which the latter were found to be lower. The most abundance species were propane and toluene. Ratios of benzene over toluene suggested that additional toluene mixing ratios was owing to industrial emission, which was particularly larger during weekdays. Comparison between C2Cl4 and CH3Cl mixing ratios obtained for suburban Tokyo reveal a relatively lower influence of biomass burning than suburban Bangkok. Elucidating by Ozone Formation Potential, toluene was found to contribute the most to O3 production followed by ethylene, m-,p-xylene, and propylene.

Mixing of secondary organic aerosols versus relative humidity

PubMed Central

Ye, Qing; Robinson, Ellis Shipley; Ding, Xiang; Ye, Penglin

2016-01-01

Atmospheric aerosols exert a substantial influence on climate, ecosystems, visibility, and human health. Although secondary organic aerosols (SOA) dominate fine-particle mass, they comprise myriad compounds with uncertain sources, chemistry, and interactions. SOA formation involves absorption of vapors into particles, either because gas-phase chemistry produces low-volatility or semivolatile products that partition into particles or because more-volatile organics enter particles and react to form lower-volatility products. Thus, SOA formation involves both production of low-volatility compounds and their diffusion into particles. Most chemical transport models assume a single well-mixed phase of condensing organics and an instantaneous equilibrium between bulk gas and particle phases; however, direct observations constraining diffusion of semivolatile organics into particles containing SOA are scarce. Here we perform unique mixing experiments between SOA populations including semivolatile constituents using quantitative, single-particle mass spectrometry to probe any mass-transfer limitations in particles containing SOA. We show that, for several hours, particles containing SOA from toluene oxidation resist exchange of semivolatile constituents at low relative humidity (RH) but start to lose that resistance above 20% RH. Above 40% RH, the exchange of material remains constant up to 90% RH. We also show that dry particles containing SOA from α-pinene ozonolysis do not appear to resist exchange of semivolatile compounds. Our interpretation is that in-particle diffusion is not rate-limiting to mass transfer in these systems above 40% RH. To the extent that these systems are representative of ambient SOA, we conclude that diffusion limitations are likely not common under typical ambient boundary layer conditions. PMID:27791066

Mixing of secondary organic aerosols versus relative humidity.

PubMed

Ye, Qing; Robinson, Ellis Shipley; Ding, Xiang; Ye, Penglin; Sullivan, Ryan C; Donahue, Neil M

2016-10-24

Atmospheric aerosols exert a substantial influence on climate, ecosystems, visibility, and human health. Although secondary organic aerosols (SOA) dominate fine-particle mass, they comprise myriad compounds with uncertain sources, chemistry, and interactions. SOA formation involves absorption of vapors into particles, either because gas-phase chemistry produces low-volatility or semivolatile products that partition into particles or because more-volatile organics enter particles and react to form lower-volatility products. Thus, SOA formation involves both production of low-volatility compounds and their diffusion into particles. Most chemical transport models assume a single well-mixed phase of condensing organics and an instantaneous equilibrium between bulk gas and particle phases; however, direct observations constraining diffusion of semivolatile organics into particles containing SOA are scarce. Here we perform unique mixing experiments between SOA populations including semivolatile constituents using quantitative, single-particle mass spectrometry to probe any mass-transfer limitations in particles containing SOA. We show that, for several hours, particles containing SOA from toluene oxidation resist exchange of semivolatile constituents at low relative humidity (RH) but start to lose that resistance above 20% RH. Above 40% RH, the exchange of material remains constant up to 90% RH. We also show that dry particles containing SOA from α-pinene ozonolysis do not appear to resist exchange of semivolatile compounds. Our interpretation is that in-particle diffusion is not rate-limiting to mass transfer in these systems above 40% RH. To the extent that these systems are representative of ambient SOA, we conclude that diffusion limitations are likely not common under typical ambient boundary layer conditions.

ORGANIC COMPOUNDS MEASURED IN PM2.5 DURING NEOPS

EPA Science Inventory

Secondary formation of submicron ambient particulate matter occurs when organic and inorganic constituents having sufficiently low volatility condense onto preexisting particles in the atmosphere. The presence of the resulting submicron particles has led to three important env...

CYP76C1 (Cytochrome P450)-Mediated Linalool Metabolism and the Formation of Volatile and Soluble Linalool Oxides in Arabidopsis Flowers: A Strategy for Defense against Floral Antagonists[OPEN

PubMed Central

Lesot, Agnès; Ginglinger, Jean-François; Beran, Franziska; Schneider, Bernd; Leiss, Kirsten; Werck-Reichhart, Danièle

2015-01-01

The acyclic monoterpene alcohol linalool is one of the most frequently encountered volatile compounds in floral scents. Various linalool oxides are usually emitted along with linalool, some of which are cyclic, such as the furanoid lilac compounds. Recent work has revealed the coexistence of two flower-expressed linalool synthases that produce the (S)- or (R)-linalool enantiomers and the involvement of two P450 enzymes in the linalool oxidation in the flowers of Arabidopsis thaliana. Partially redundant enzymes may also contribute to floral linalool metabolism. Here, we provide evidence that CYP76C1 is a multifunctional enzyme that catalyzes a cascade of oxidation reactions and is the major linalool metabolizing oxygenase in Arabidopsis flowers. Based on the activity of the recombinant enzyme and mutant analyses, we demonstrate its prominent role in the formation of most of the linalool oxides identified in vivo, both as volatiles and soluble conjugated compounds, including 8-hydroxy, 8-oxo, and 8-COOH-linalool, as well as lilac aldehydes and alcohols. Analysis of insect behavior on CYP76C1 mutants and in response to linalool and its oxygenated derivatives demonstrates that CYP76C1-dependent modulation of linalool emission and production of linalool oxides contribute to reduced floral attraction and favor protection against visitors and pests. PMID:26475865

User’s guide to the collection and analysis of tree cores to assess the distribution of subsurface volatile organic compounds

USGS Publications Warehouse

Vroblesky, Don A.

2008-01-01

Analysis of the volatile organic compound content of tree cores is an inexpensive, rapid, simple approach to examining the distribution of subsurface volatile organic compound contaminants. The method has been shown to detect several volatile petroleum hydrocarbons and chlorinated aliphatic compounds associated with vapor intrusion and ground-water contamination. Tree cores, which are approximately 3 inches long, are obtained by using an increment borer. The cores are placed in vials and sealed. After a period of equilibration, the cores can be analyzed by headspace analysis gas chromatography. Because the roots are exposed to volatile organic compound contamination in the unsaturated zone or shallow ground water, the volatile organic compound concentrations in the tree cores are an indication of the presence of subsurface volatile organic compound contamination. Thus, tree coring can be used to detect and map subsurface volatile organic compound contamination. For comparison of tree-core data at a particular site, it is important to maintain consistent methods for all aspects of tree-core collection, handling, and analysis. Factors affecting the volatile organic compound concentrations in tree cores include the type of volatile organic compound, the tree species, the rooting depth, ground-water chemistry, the depth to the contaminated horizon, concentration differences around the trunk related to variations in the distribution of subsurface volatile organic compounds, concentration differences with depth of coring related to volatilization loss through the bark and possibly other unknown factors, dilution by rain, seasonal influences, sorption, vapor-exchange rates, and within-tree volatile organic compound degradation.

Effect of sublethal preculturing on the survival of probiotics and metabolite formation in set-yoghurt.

PubMed

Settachaimongkon, Sarn; van Valenberg, Hein J F; Winata, Vera; Wang, Xiaoxi; Nout, M J Robert; van Hooijdonk, Toon C M; Zwietering, Marcel H; Smid, Eddy J

2015-08-01

The objective of this study was to investigate the effect of preculturing of Lactobacillus rhamnosus GG and Bifidobacterium animalis subsp. lactis BB12 under sublethal stress conditions on their survival and metabolite formation in set-yoghurt. Prior to co-cultivation with yoghurt starters in milk, the two probiotic strains were precultured under sublethal stress conditions (combinations of elevated NaCl and low pH) in a batch fermentor. The activity of sublethally precultured probiotics was evaluated during fermentation and refrigerated storage by monitoring bacterial population dynamics, milk acidification and changes in volatile and non-volatile metabolite profiles of set-yoghurt. The results demonstrated adaptive stress responses of the two probiotic strains resulting in their viability improvement without adverse influence on milk acidification. A complementary metabolomic approach using SPME-GC/MS and (1)H-NMR resulted in the identification of 35 volatiles and 43 non-volatile polar metabolites, respectively. Principal component analysis revealed substantial impact of the activity of sublethally precultured probiotics on metabolite formation demonstrated by distinctive volatile and non-volatile metabolite profiles of set-yoghurt. Changes in relative abundance of various aroma compounds suggest that incorporation of stress-adapted probiotics considerably influences the organoleptic quality of product. This study provides new information on the application of stress-adapted probiotics in an actual food-carrier environment. Copyright © 2015 Elsevier Ltd. All rights reserved.

A Rabbit Model for Assessment of Volatile Metabolite Changes Observed from Skin: a Pressure Ulcer Case Study

PubMed Central

Schivo, Michael; Aksenov, Alexander A; Pasamontes, Alberto; Cumeras, Raquel; Weisker, Sandra; Oberbauer, Anita M; Davis, Cristina E

2017-01-01

Human skin presents a large, easily accessible matrix that is potentially useful for diagnostic applications based on whole body metabolite changes – some of which will be volatile and detected using minimally invasive tools. Unfortunately, identifying skin biomarkers that can be reliably linked to a particular condition is challenging due to a large variability of genetics, dietary intake, environmental exposures within human populations. This leads to a paucity of clinically validated volatile skin biomarker compounds. Animal models present a very convenient and attractive way to circumvent many of the variability issues. The rabbit (Leporidae) is a potentially logistically useful model to study the skin metabolome, but very limited knowledge of its skin metabolites exists. Here we present the first comprehensive assessment of the volatile fraction of rabbit skin metabolites using polydimethylsiloxane sorbent patch sampling in conjunction with gas chromatography / mass spectrometry (GC/MS). A collection of compounds that are secreted from rabbit skin was documented, and predominantly acyclic long-chain alkyls and alcohols were detected. We then utilized this animal model to study differences between intact skin and skin with early pressure ulcers, as the latter are a major problem in intensive care units. Four New Zealand female white rabbits underwent ulcer formation on one ear with the other ear as a control. Early-stage ulcers were created with neodymium magnets. Histologic analysis showed acute heterophilic dermatitis, edema, and micro-hemorrhage on the ulcerated ears with normal findings on the control ears. The metabolomic analysis revealed subtle but noticeable differences, with several compounds associated with the oxidative stress-related degradation of lipids found to be present in greater abundances in ulcerated ears. The metabolomic findings correlate with histologic evidence of early-stage ulcers. We postulate that the Leporidae model recapitulated the vascular changes associated with ulcer formation. This study illustrates the potential usefulness of the Leporidae model for skin metabolome studies as illustrated by this study of early-stage ulcer formation. PMID:28068292

Effect of pH, temperature, and moisture on the formation of volatile compounds in glycine/glucose model systems.

PubMed

Ames, J M; Guy, R C; Kipping, G J

2001-09-01

Mixtures of glycine, glucose, and starch were extrusion cooked using sodium hydroxide at 0, 3, and 6 g/L of extruder water feed, 18% moisture, and 120, 150, and 180 degrees C target die temperatures, giving extrudates with pH values of 5.6, 6.8, and 7.4. Freeze-dried equimolar solutions of glucose and glycine were heated either dry or after equilibration to approximately 13% moisture at 180 degrees C in a reaction-tube system designed to mimic the heating profile in an extruder. Volatile compounds were isolated onto Tenax and analyzed by gas chromatography-mass spectrometry. For the extrudates, total yields of volatiles increased with decreasing pH at 180 degrees C, reached a maximum at pH 6.8 at 150 degrees C, and increased with increasing pH at 120 degrees C. Amounts increased with temperature at all pH values. Pyrazines were the most abundant class for all sets of conditions (54-79% of total volatiles). Pyrroles, ketones, furans, oxazoles, and pyridines were also identified. Yields of volatiles from the reaction-tube samples increased by >60% in the moist system. Levels of individual classes also increased in the presence of moisture, except pyrazines, which decreased approximately 3.5-fold. Twenty-one of the compounds were common to the reaction-tube samples and the extrudates.

Speciated measurements of semivolatile and intermediate volatility organic compounds (S/IVOCs) in a pine forest during BEACHON-RoMBAS 2011

DOE PAGES

Chan, A. W. H.; Kreisberg, N. M.; Hohaus, T.; ...

2016-02-02

Understanding organic composition of gases and particles is essential to identifying sources and atmospheric processing leading to organic aerosols (OA), but atmospheric chemical complexity and the analytical techniques available often limit such analysis. Here we present speciated measurements of semivolatile and intermediate volatility organic compounds (S/IVOCs) using a novel dual-use instrument (SV-TAG-AMS) deployed at Manitou Forest, CO, during the Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H 2O, Organics & Nitrogen – Rocky Mountain Biogenic Aerosol Study (BEACHON-RoMBAS) 2011 campaign. This instrument provides on-line speciation of ambient organic compounds with 2 h time resolution. The species in this volatility range aremore » complex in composition, but their chemical identities reveal potential sources. Observed compounds of biogenic origin include sesquiterpenes with molecular formula C 15H 24 (e.g., β-caryophyllene and longifolene), which were most abundant at night. A variety of other biogenic compounds were observed, including sesquiterpenoids with molecular formula C 15H 22, abietatriene and other terpenoid compounds. Many of these compounds have been identified in essential oils and branch enclosure studies but were observed in ambient air for the first time in our study. Semivolatile polycyclic aromatic hydrocarbons (PAHs) and alkanes were observed with highest concentrations during the day and the dependence on temperature suggests the role of an evaporative source. Using statistical analysis by positive matrix factorization (PMF), we classify observed S/IVOCs by their likely sources and processes, and characterize them based on chemical composition. The total mass concentration of elutable S/IVOCs was estimated to be on the order of 0.7 µg m –3 and their volatility distributions are estimated for modeling aerosol formation chemistry.« less

Speciated measurements of semivolatile and intermediate volatility organic compounds (S/IVOCs) in a pine forest during BEACHON-RoMBAS 2011

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chan, A. W. H.; Kreisberg, N. M.; Hohaus, T.

Understanding organic composition of gases and particles is essential to identifying sources and atmospheric processing leading to organic aerosols (OA), but atmospheric chemical complexity and the analytical techniques available often limit such analysis. Here we present speciated measurements of semivolatile and intermediate volatility organic compounds (S/IVOCs) using a novel dual-use instrument (SV-TAG-AMS) deployed at Manitou Forest, CO, during the Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H 2O, Organics & Nitrogen – Rocky Mountain Biogenic Aerosol Study (BEACHON-RoMBAS) 2011 campaign. This instrument provides on-line speciation of ambient organic compounds with 2 h time resolution. The species in this volatility range aremore » complex in composition, but their chemical identities reveal potential sources. Observed compounds of biogenic origin include sesquiterpenes with molecular formula C 15H 24 (e.g., β-caryophyllene and longifolene), which were most abundant at night. A variety of other biogenic compounds were observed, including sesquiterpenoids with molecular formula C 15H 22, abietatriene and other terpenoid compounds. Many of these compounds have been identified in essential oils and branch enclosure studies but were observed in ambient air for the first time in our study. Semivolatile polycyclic aromatic hydrocarbons (PAHs) and alkanes were observed with highest concentrations during the day and the dependence on temperature suggests the role of an evaporative source. Using statistical analysis by positive matrix factorization (PMF), we classify observed S/IVOCs by their likely sources and processes, and characterize them based on chemical composition. The total mass concentration of elutable S/IVOCs was estimated to be on the order of 0.7 µg m –3 and their volatility distributions are estimated for modeling aerosol formation chemistry.« less

Unusual analyte-matrix adduct ions and mechanism of their formation in MALDI TOF MS of benzene-1,3,5-tricarboxamide and urea compounds.

PubMed

Lou, Xianwen; Fransen, Michel; Stals, Patrick J M; Mes, Tristan; Bovee, Ralf; van Dongen, Joost J L; Meijer, E W

2013-09-01

Analyte-matrix adducts are normally absent under typical matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS) conditions. Interestingly, though, in the analysis of several types of organic compounds synthesized in our laboratory, analyte-matrix adduct ion peaks were always recorded when common MALDI matrices such as 4-hydroxy-α-cyanocinnamic acid (CHCA) were used. These compounds are mainly those with a benzene-1,3,5-tricarboxamide (BTA) or urea moiety, which are important building blocks to make new functional supramolecular materials. The possible mechanism of the adduct formation was investigated. A shared feature of the compounds studied is that they can form intermolecular hydrogen bonding with matrices like CHCA. The intermolecular hydrogen bonding will make the association between analyte ions and matrix molecules stronger. As a result, the analyte ions and matrix molecules in MALDI clusters will become more difficult to be separated from each other. Furthermore, it was found that analyte ions were mainly adducted with matrix salts, which is probably due to the much lower volatility of the salts compared with that of their corresponding matrix acids. It seems that the analyte-matrix adduct formation for our compounds are caused by the incomplete evaporation of matrix molecules from the MALDI clusters because of the combined effects of enhanced intermolecular interaction between analyte-matrix and of the low volatility of matrix salts. Based on these findings, strategies to suppress the analyte-matrix adduction are briefly discussed. In return, the positive results of using these strategies support the proposed mechanism of the analyte-matrix adduct formation.

[Analyze on volatile compounds of Antrodia camphorata using HS-SPME-GC-MS].

PubMed

He, Zhe; Lu, Zhen-Ming; Xu, Hong-Yu; Shi, Jing-Song; Xu, Zheng-Hong

2011-11-01

To analyze the volatile compounds of Antrodia camphorata in solid-state and submerged cultures. A headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry(GC-MS) were used to evaluate the profile of the volatile compounds. 49 volatile compounds were identified in A. camphorata mycelia in submerged culture, while 43 volatile compounds were identified in mycelia in solid-state culture. 1-octen-3-ol, 3-octanone, 1-octen-3-ylacetate, acetic acid octyl ester and ethanol were the main volatile compounds in A. camphorata mycelia in submerged culture, while 1-octen-3-ol, 3-octanone, 3-methyl-butyraldenhyde, gamma-podecalactone and methyl 2-furozte were the most potent key volatile compounds in mycelia in solid-state culture. The volatile compounds in the mycelia of A. camphorata in solid-state and submerged cultures are similar but their relative contents are different.

Evaluation of Volatile Species in Green Monopropellant Project

NASA Technical Reports Server (NTRS)

Greene, Benjamin

2015-01-01

NASA is interested in green monopropellants to replace hydrazine in reaction control systems (RCSs). Some current NASA programs require reduced vapor pressure and low toxicity monopropellant (green) and superior performance (specific impulse and density) formulations. Earlier vapor phase studies of a candidate green monopropellant at the NASA White Sands Test Facility (WSTF) showed the presence of a volatile species that warranted further investigation. The purpose of this study was to further characterize the volatile species and to evaluate it. The evaluation was with respect to whether the volatile species was an impurity or how it is formed, and to use that information to examine whether its presence as an impurity can be eliminated during formulation. The evaluation also considered whether formation of the volatile impurity could be prevented while not compromising the propellant. To reduce variables associated with evaluation of the propellant formulation as a whole, a precursor to one of the individual components in the propellant formulation was subjected to a NASA Standard 6001B Flammability, Off-gassing, and Compatibility Requirements and Test Procedures "Determination of Off-gassed Products (Test 7)". Testing took place in the NASA WSTF Molecular Desorption and Analysis Laboratory. One gram of the precursor was placed in a flask within a specimen container. After thermal conditioning for 72 +/- 1 h at 50 +/- 3 deg C (122 +/- 5 deg F), the atmosphere inside the specimen container was analyzed for off-gassed compounds by cryotrap gas chromatography-mass spectrometry (GC-MS) and fixed sample loop GC-flame ionization detection (GC-FID). The specimen container used was glass to minimize potential catalytic surfaces. The identification of compounds was difficult due to the complexity of the vapor phase concentrations and overlapping chromatographic peaks and mass spectra. However, eleven compounds were specifically identified and five compounds or classes of compounds were reported as unidentified. Quantitation of most of the compounds, including unidentified compounds, was as methane. Quantitating compounds or classes of compounds that were detected but for which specific calibration is not established as methane is in accordance with the Test 7 standard protocol. The thermal decomposition temperature of the precursor was significantly higher than the test temperature. Based on thermal decomposition temperature and on an examination of the structure and chemistry of the identified volatile species, the presence of the volatile species appears to be chemically reasonable with respect to the propellant formulation and is at this time attributed to impurities. Further examination of the overall propellant formulation process (including the individual components' synthesis processes) and process quality control (including purity of reagents and possible decomposition reactions) is indicated.

Off-flavor related volatiles in soymilk as affected by soybean variety, grinding, and heat-processing methods.

PubMed

Zhang, Yan; Guo, Shuntang; Liu, Zhisheng; Chang, Sam K C

2012-08-01

Off-flavor of soymilk is a barrier to the acceptance of consumers. The objectionable soy odor can be reduced through inhibition of their formation or through removal after being formed. In this study, soymilk was prepared by three grinding methods (ambient, cold, and hot grinding) from two varieties (yellow Prosoy and a black soybean) before undergoing three heating processes: stove cooking, one-phase UHT (ultrahigh temperature), and two-phase UHT process using a Microthermics direct injection processor, which was equipped with a vacuuming step to remove injected water and volatiles. Eight typical soy odor compounds, generated from lipid oxidation, were extracted by a solid-phase microextraction method and analyzed by gas chromatography. The results showed that hot grinding and cold grinding significantly reduced off-flavor as compared with ambient grinding, and hot grinding achieved the best result. The UHT methods, especially the two-phase UHT method, were effective to reduce soy odor. Different odor compounds showed distinct concentration patterns because of different formation mechanisms. The two varieties behaved differently in odor formation during the soymilk-making process. Most odor compounds could be reduced to below the detection limit through a combination of hot grinding and two-phase UHT processing. However, hot grinding gave lower solid and protein recoveries in soymilk.

Effects of nitrogen nutrients on the volatile organic compound emissions from Microcystis aeruginosa.

PubMed

Zuo, Zhaojiang; Yang, Lin; Chen, Silan; Ye, Chaolin; Han, Yujie; Wang, Sutong; Ma, Yuandan

2018-06-06

Cyanobacteria release abundant volatile organic compounds (VOCs), which can poison other algae and cause water odor. To uncover the effects of nitrogen (N) nutrients on the formation of cyanobacteria VOCs, the cell growth, VOC emission and the expression of genes involving in VOC formation in Microcystis aeruginosa were investigated under different N conditions. With the supplement of NaNO 3 , NaNO 2 , NH 4 Cl, urea, Serine (Ser) and Arginine (Arg) as the sole N source, NaNO 3 , urea and Arg showed the best effects on M. aeruginosa cell growth, and limited N supply inhibited the cell growth. M. aeruginosa released 26, 25, 23, 27, 23 and 25 compounds, respectively, in response to different N forms, including furans, sulfocompounds, terpenoids, benzenes, hydrocarbons, aldehydes, and esters. Low-N especially Non-N condition markedly promoted the VOC emission. Under Non-N condition, four up-regulated genes involving in VOC precursor formation were identified, including the genes of pyruvate kinase, malic enzyme and phosphotransacetylase for terpenoids, the gene of aspartate aminotransferase for benzenes and sulfocompounds. In eutrophic water, cyanobacteria release different VOC blends using various N forms, and the reduction of N amount caused by cyanobacteria massive growth can promote algal VOC emission by up-regulating the gene expression. Copyright © 2018 Elsevier Inc. All rights reserved.

Study of aroma formation and transformation during the manufacturing process of Biluochun green tea in Yunnan Province by HS-SPME and GC-MS.

PubMed

Wang, Chen; Lv, Shidong; Wu, Yuanshuang; Lian, Ming; Gao, Xuemei; Meng, Qingxiong

2016-10-01

Biluochun is a typical non-fermented tea and is also famous for its unique aroma in China. Few studies have been performed to evaluate the effect of the manufacturing process on the formation and content of its aroma. The volatile components were extracted at different manufacturing process steps of Biluochun green tea using fully automated headspace solid-phase microextraction (HS-SPME) and further characterised by gas chromatography-mass spectrometry (GC-MS). Among 67 volatile components collected, the fractions of linalool oxides, β-ionone, phenylacetaldehyde, aldehydes, ketones, and nitrogen compounds were increased while alcohols and hydrocarbons declined during the manufacturing process. The aroma compounds decreased the most during the drying steps. We identified a number of significantly changed components that can be used as markers and quality control during the producing process of Biluochun. The drying step played a major role in the aroma formation of green tea products and should be the most important step for quality control. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Aromatic volatile organic compounds and their role in ground-level ozone formation in Russia

NASA Astrophysics Data System (ADS)

Berezina, E. V.; Moiseenko, K. B.; Skorokhod, A. I.; Elansky, N. F.; Belikov, I. B.

2017-05-01

This paper reports proton mass spectrometry data on aromatic volatile organic compounds (VOCs) (benzene, toluene, phenol, styrene, xylene, and propylbenzene) obtained in different Russian regions along the Trans-Siberian Railway from Moscow to Vladivostok, based on expedition data retrieved using the TRO-ICA-12 mobile laboratory in the summer of 2008. The contribution of aromatic VOCs to ozone formation in the cities and regions along the measurement route has been estimated quantitatively. The greatest contribution of aromatic VOCs to ozone formation is characteristic of large cities along the Trans-Siberian Railway (up to 7.5 ppbv O3) specified by the highest concentrations of aromatic VOCs (1-1.7 ppbv) and nitrogen oxides (>20 ppbv). The results obtained are indicative of a considerable contribution (30-50%) of anthropogenic emissions of VOCs to photochemical ozone generation in the large cities along the Trans-Siberian Railway in hot and dry weather against the background of a powerful natural factor such as isoprene emissions controlling the regional balance of ground-level ozone in warm seasons.

Chemistry of Volatile Organic Compounds in the Los Angeles Basin: Formation of Oxygenated Compounds and Determination of Emission Ratios

NASA Astrophysics Data System (ADS)

de Gouw, J. A.; Gilman, J. B.; Kim, S.-W.; Alvarez, S. L.; Dusanter, S.; Graus, M.; Griffith, S. M.; Isaacman-VanWertz, G.; Kuster, W. C.; Lefer, B. L.; Lerner, B. M.; McDonald, B. C.; Rappenglück, B.; Roberts, J. M.; Stevens, P. S.; Stutz, J.; Thalman, R.; Veres, P. R.; Volkamer, R.; Warneke, C.; Washenfelder, R. A.; Young, C. J.

2018-02-01

We analyze an expanded data set of oxygenated volatile organic compounds (OVOCs) in air measured by several instruments at a surface site in Pasadena near Los Angeles during the National Oceanic and Atmospheric Administration California Nexus study in 2010. The contributions of emissions, chemical formation, and removal are quantified for each OVOC using CO as a tracer of emissions and the OH exposure of the sampled air masses calculated from hydrocarbon ratios. The method for separating emissions from chemical formation is evaluated using output for Pasadena from the Weather Research and Forecasting-Chemistry model. The model is analyzed by the same method as the measurement data, and the emission ratios versus CO calculated from the model output agree for ketones with the inventory used in the model but overestimate aldehydes by 70%. In contrast with the measurements, nighttime formation of OVOCs is significant in the model and is attributed to overestimated precursor emissions and overestimated rate coefficients for the reactions of the precursors with ozone and NO3. Most measured aldehydes correlated strongly with CO at night, suggesting a contribution from motor vehicle emissions. However, the emission ratios of most aldehydes versus CO are higher than those reported in motor vehicle emissions and the aldehyde sources remain unclear. Formation of several OVOCs is investigated in terms of the removal of specific precursors. Direct emissions of alcohols and aldehydes contribute significantly to OH reactivity throughout the day, and these emissions should be accurately represented in models describing ozone formation.

Speciation of mercury compounds by differential atomization - atomic absorption spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robinson, J.W.; Skelly, E.M.

This paper describes the dual stage atomization technique which allows speciation of several mercury-containing compounds in aqueous solution and in biological fluids. The technique holds great promise for further speciation studies. Accurate temperature control, expecially at temperatures less than 200/sup 0/C, is needed to separate the extremely volatile mercury halides and simple organomercurials from each other. Studies with mercury salts and EDTA, L-cysteine and dithioxamide demonstrate that this technique may be used to study the extent of complex formation. Investigations of biological fluids indicate that there is a single predominant form of mercury in sweat and a single predominant formmore » of mercury in urine. The mercury compound in urine is more volatile than that in sweat. Both quantitative and qualitative analyses are possible with this technique.« less

Heterogeneous Nucleation of Trichloroethylene Ozonation Products in the Formation of New Fine Particles

NASA Astrophysics Data System (ADS)

Wang, Ning; Sun, Xiaomin; Chen, Jianmin; Li, Xiang

2017-02-01

Free radicals in atmosphere have played an important role in the atmospheric chemistry. The chloro-Criegee free radicals are produced easily in the decomposition of primary ozonide (POZ) of the trichloroethylene, and can react with O2, NO, NO2, SO2 and H2O subsequently. Then the inorganic salts, polar organic nitrogen and organic sulfur compounds, oxygen-containing heterocyclic intermediates and polyhydroxy compounds can be obtained. The heterogeneous nucleation of oxidation intermediates in the formation of fine particles is investigated using molecular dynamics simulation. The detailed nucleation processes are reported. According to molecular dynamics simulation, the nucleation with a diameter of 2 nm is formed in the Organic Compounds-(NH4)2SO4-H2O system. The spontaneous nucleation is an important process in the formation of fine particles in atmosphere. The model study gives a good example from volatile organic compounds to new fine particles.

A review of volatile compounds in tektites, and carbon content and isotopic composition of moldavite glass

NASA Astrophysics Data System (ADS)

Žák, Karel; SkáLA, Roman; Šanda, Zdeněk.; Mizera, Jiří.

2012-06-01

Tektites, natural silica-rich glasses produced during impact events, commonly contain bubbles. The paper reviews published data on pressure and composition of a gas phase contained in the tektite bubbles and data on other volatile compounds which can be released from tektites by either high-temperature melting or by crushing or milling under vacuum. Gas extraction from tektites using high-temperature melting generally produced higher gas yield and different gas composition than the low-temperature extraction using crushing or milling under vacuum. The high-temperature extraction obviously releases volatiles not only from the bubbles, but also volatile compounds contained directly in the glass. Moreover, the gas composition can be modified by reactions between the released gases and the glass melt. Published data indicate that besides CO2 and/or CO in the bubbles, another carbon reservoir is present directly in the tektite glass. To clarify the problem of carbon content and carbon isotopic composition of the tektite glass, three samples from the Central European tektite strewn field—moldavites—were analyzed. The samples contained only 35-41 ppm C with δ13C values in the range from -28.5 to -29.9‰ VPDB. This indicates that terrestrial organic matter was a dominant carbon source during moldavite formation.

ASSESSMENT OF EXISTING TEST REPORTS FOR EVALUATING VOC CONTROL EFFECTIVENESS

EPA Science Inventory

The report outlines the approach taken by EPA to review existing test reports for evaluating volatile organic compound (VOC) control device effectiveness and identifying missing control device effectiveness information. A format is presented to provide guidance and serve as the b...

Assessment of the antioxidant activity of Bifurcaria bifurcata aqueous extract on canola oil. Effect of extract concentration on the oxidation stability and volatile compound generation during oil storage.

PubMed

Agregán, Rubén; Lorenzo, José M; Munekata, Paulo E S; Dominguez, Ruben; Carballo, Javier; Franco, Daniel

2017-09-01

In this research the antioxidant activity of water extracts of Bifurcaria bifurcata (BBE) at different dose against butylated hydroxytoluene (BHT) was evaluated in canola oil. Water extracts were firstly characterized in terms of total solid and polyphenolic compound contents, and their antioxidant activity together with that of BHT was evaluated using several in vitro tests (DPPH, ABTS, ORAC and FRAP). Next, the progress of lipid oxidation was assessed in canola oil added with five BBE concentrations (200, 400, 600, 800 and 1000ppm) and two BHT concentrations (50 and 200ppm) using an accelerated oxidation test. The progress in lipid oxidation was monitored by assessing some chemical indices (peroxide value, p-anisidine value, and conjugated dienes) during oil storage and some volatile compounds at the end of the storage period. BBE showed a significant antioxidant effect, being this ability concentration-dependent. The extent of lipid oxidation was inversely related to BBE dose, specially with regard to primary oxidation products. At the highest level of BBE, significant decreases of primary and secondary oxidation products, with respect to the control, were obtained with reduction percentages of 71.53%, 72.78%, 68.17% and 71.3% for peroxides, conjugated dienes, p-anisidine and TOTOX values, respectively. A level of 600ppm or higher concentration of the extract inhibits the lipid oxidation in a similar way than BHT at 200ppm. Regarding the inhibition of the formation of volatile compounds, both BBE and BHT strongly inhibited the formation of volatiles during oil storage, being this inhibition similar for all the concentrations of BBE and BHT essayed. Overall, results indicated that BBE can be used as a potential natural additive for improving oxidative stability of canola oil. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of rehydration nutrients on H2S metabolism and formation of volatile sulfur compounds by the wine yeast VL3.

PubMed

Winter, Gal; Henschke, Paul A; Higgins, Vincent J; Ugliano, Maurizio; Curtin, Chris D

2011-11-02

In winemaking, nutrient supplementation is a common practice for optimising fermentation and producing quality wine. Nutritionally suboptimal grape juices are often enriched with nutrients in order to manipulate the production of yeast aroma compounds. Nutrients are also added to active dry yeast (ADY) rehydration media to enhance subsequent fermentation performance. In this study we demonstrate that nutrient supplementation at rehydration also has a significant effect on the formation of volatile sulfur compounds during wine fermentations. The concentration of the 'fruity' aroma compounds, the polyfunctional thiols 3-mercaptohexan-1-ol (3MH) and 3-mercaptohexyl acetate (3MHA), was increased while the concentration of the 'rotten egg' aroma compound, hydrogen sulfide (H2S), was decreased. Nutrient supplementation of the rehydration media also changed the kinetics of H2S production during fermentation by advancing onset of H2S production. Microarray analysis revealed that this was not due to expression changes within the sulfate assimilation pathway, which is known to be a major contributor to H2S production. To gain insight into possible mechanisms responsible for this effect, a component of the rehydration nutrient mix, the tri-peptide glutathione (GSH) was added at rehydration and studied for its subsequent effects on H2S formation. GSH was found to be taken up during rehydration and to act as a source for H2S during the following fermentation. These findings represent a potential approach for managing sulfur aroma production through the use of rehydration nutrients.

Low-molecular-weight organoiodine and organobromine compounds released by polar macroalgae--the influence of abiotic factors.

PubMed

Laturnus, F; Giese, B; Wiencke, C; Adams, F C

2000-01-01

The influence of temperature, light, salinity and nutrient availability on the release of volatile halogenated hydrocarbons was investigated in the Antarctic red macroalgal species Gymnogongrus antarcticus Skottsberg. Compared to standard culture condition, an increase in the release rates of iodocompounds was generally found for the exposure of the alga to altered environmental conditions. Macroalgae exhibited higher release rates after adaptation for two months to the changed factors, than after short-term exposure. Monitoring the release rates during a 24 h incubation period (8.25 h light, 15.75 h darkness) showed that changes between light and dark periods had no influence on the release of volatile halocarbons. Compounds like bromoform and 1-iodobutane exhibited constant release rates during the 24 h period. The formation mechanisms and biological role of volatile organohalogens are discussed. Although marine macroalgae are not considered to be the major source of biogenically-produced volatile organohalogens, they contribute significantly to the bromine and iodine cycles in the environment. Under possible environmental changes like global warming and uncontrolled entrophication of the oceans their significance may be increase.

Volatile flavor compounds in yogurt: a review.

PubMed

Cheng, Hefa

2010-11-01

Considerable knowledge has been accumulated on the volatile compounds contributing to the aroma and flavor of yogurt. This review outlines the production of the major flavor compounds in yogurt fermentation and the analysis techniques, both instrumental and sensory, for quantifying the volatile compounds in yogurt. The volatile compounds that have been identified in plain yogurt are summarized, with the few key aroma compounds described in detail. Most flavor compounds in yogurt are produced from lipolysis of milkfat and microbiological transformations of lactose and citrate. More than 100 volatiles, including carbonyl compounds, alcohols, acids, esters, hydrocarbons, aromatic compounds, sulfur-containing compounds, and heterocyclic compounds, are found in yogurt at low to trace concentrations. Besides lactic acid, acetaldehyde, diacetyl, acetoin, acetone, and 2-butanone contribute most to the typical aroma and flavor of yogurt. Extended storage of yogurt causes off-flavor development, which is mainly attributed to the production of undesired aldehydes and fatty acids during lipid oxidation. Further work on studying the volatile flavor compounds-matrix interactions, flavor release mechanisms, and the synergistic effect of flavor compounds, and on correlating the sensory properties of yogurt with the compositions of volatile flavor compounds are needed to fully elucidate yogurt aroma and flavor.

CYP79D enzymes contribute to jasmonic acid-induced formation of aldoximes and other nitrogenous volatiles in two Erythroxylum species.

PubMed

Luck, Katrin; Jirschitzka, Jan; Irmisch, Sandra; Huber, Meret; Gershenzon, Jonathan; Köllner, Tobias G

2016-10-04

Amino acid-derived aldoximes and nitriles play important roles in plant defence. They are well-known as precursors for constitutive defence compounds such as cyanogenic glucosides and glucosinolates, but are also released as volatiles after insect feeding. Cytochrome P450 monooxygenases (CYP) of the CYP79 family catalyze the formation of aldoximes from the corresponding amino acids. However, the majority of CYP79s characterized so far are involved in cyanogenic glucoside or glucosinolate biosynthesis and only a few have been reported to be responsible for nitrogenous volatile production. In this study we analysed and compared the jasmonic acid-induced volatile blends of two Erythroxylum species, the cultivated South American crop species E. coca and the African wild species E. fischeri. Both species produced different nitrogenous compounds including aliphatic aldoximes and an aromatic nitrile. Four isolated CYP79 genes (two from each species) were heterologously expressed in yeast and biochemically characterized. CYP79D62 from E. coca and CYP79D61 and CYP79D60 from E. fischeri showed broad substrate specificity in vitro and converted L-phenylalanine, L-isoleucine, L-leucine, L-tryptophan, and L-tyrosine into the respective aldoximes. In contrast, recombinant CYP79D63 from E. coca exclusively accepted L-tryptophan as substrate. Quantitative real-time PCR revealed that CYP79D60, CYP79D61, and CYP79D62 were significantly upregulated in jasmonic acid-treated Erythroxylum leaves. The kinetic parameters of the enzymes expressed in vitro coupled with the expression patterns of the corresponding genes and the accumulation and emission of (E/Z)-phenylacetaldoxime, (E/Z)-indole-3-acetaldoxime, (E/Z)-3-methylbutyraldoxime, and (E/Z)-2-methylbutyraldoxime in jasmonic acid-treated leaves suggest that CYP79D60, CYP79D61, and CYP79D62 accept L-phenylalanine, L-leucine, L-isoleucine, and L-tryptophan as substrates in vivo and contribute to the production of volatile and semi-volatile nitrogenous defence compounds in E. coca and E. fischeri.

In situ secondary organic aerosol formation from ambient pine forest air using an oxidation flow reactor

DOE PAGES

Palm, Brett B.; Campuzano-Jost, Pedro; Ortega, Amber M.; ...

2016-03-08

An oxidation flow reactor (OFR) is a vessel inside which the concentration of a chosen oxidant can be increased for the purpose of studying SOA formation and aging by that oxidant. During the BEACHON-RoMBAS (Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H 2O, Organics & Nitrogen–Rocky Mountain Biogenic Aerosol Study) field campaign, ambient pine forest air was oxidized by OH radicals in an OFR to measure the amount of SOA that could be formed from the real mix of ambient SOA precursor gases, and how that amount changed with time as precursors changed. High OH concentrations and short residence times allowedmore » for semicontinuous cycling through a large range of OH exposures ranging from hours to weeks of equivalent (eq.) atmospheric aging. A simple model is derived and used to account for the relative timescales of condensation of low-volatility organic compounds (LVOCs) onto particles; condensational loss to the walls; and further reaction to produce volatile, non-condensing fragmentation products. More SOA production was observed in the OFR at nighttime (average 3 µg m –3 when LVOC fate corrected) compared to daytime (average 0.9 µg m –3 when LVOC fate corrected), with maximum formation observed at 0.4–1.5 eq. days of photochemical aging. SOA formation followed a similar diurnal pattern to monoterpenes, sesquiterpenes, and toluene+ p-cymene concentrations, including a substantial increase just after sunrise at 07:00 local time. Higher photochemical aging (>10 eq. days) led to a decrease in new SOA formation and a loss of preexisting OA due to heterogeneous oxidation followed by fragmentation and volatilization. When comparing two different commonly used methods of OH production in OFRs (OFR185 and OFR254-70), similar amounts of SOA formation were observed. We recommend the OFR185 mode for future forest studies. Concurrent gas-phase measurements of air after OH oxidation illustrate the decay of primary VOCs, production of small oxidized organic compounds, and net production at lower ages followed by net consumption of terpenoid oxidation products as photochemical age increased. New particle formation was observed in the reactor after oxidation, especially during times when precursor gas concentrations and SOA formation were largest. Approximately 4.4 times more SOA was formed in the reactor from OH oxidation than could be explained by the VOCs measured in ambient air. To our knowledge this is the first time that this has been shown when comparing VOC concentrations with SOA formation measured at the same time, rather than comparing measurements made at different times. Several recently developed instruments have quantified ambient semivolatile and intermediate-volatility organic compounds (S/IVOCs) that were not detected by a proton transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS). An SOA yield of 18–58 % from those compounds can explain the observed SOA formation. S/IVOCs were the only pool of gas-phase carbon that was large enough to explain the observed SOA formation. This work suggests that these typically unmeasured gases play a substantial role in ambient SOA formation. Our results allow ruling out condensation sticking coefficients much lower than 1. Lastly, these measurements help clarify the magnitude of potential SOA formation from OH oxidation in forested environments and demonstrate methods for interpretation of ambient OFR measurements.« less

In situ secondary organic aerosol formation from ambient pine forest air using an oxidation flow reactor

NASA Astrophysics Data System (ADS)

Palm, Brett B.; Campuzano-Jost, Pedro; Ortega, Amber M.; Day, Douglas A.; Kaser, Lisa; Jud, Werner; Karl, Thomas; Hansel, Armin; Hunter, James F.; Cross, Eben S.; Kroll, Jesse H.; Peng, Zhe; Brune, William H.; Jimenez, Jose L.

2016-03-01

An oxidation flow reactor (OFR) is a vessel inside which the concentration of a chosen oxidant can be increased for the purpose of studying SOA formation and aging by that oxidant. During the BEACHON-RoMBAS (Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics & Nitrogen-Rocky Mountain Biogenic Aerosol Study) field campaign, ambient pine forest air was oxidized by OH radicals in an OFR to measure the amount of SOA that could be formed from the real mix of ambient SOA precursor gases, and how that amount changed with time as precursors changed. High OH concentrations and short residence times allowed for semicontinuous cycling through a large range of OH exposures ranging from hours to weeks of equivalent (eq.) atmospheric aging. A simple model is derived and used to account for the relative timescales of condensation of low-volatility organic compounds (LVOCs) onto particles; condensational loss to the walls; and further reaction to produce volatile, non-condensing fragmentation products. More SOA production was observed in the OFR at nighttime (average 3 µg m-3 when LVOC fate corrected) compared to daytime (average 0.9 µg m-3 when LVOC fate corrected), with maximum formation observed at 0.4-1.5 eq. days of photochemical aging. SOA formation followed a similar diurnal pattern to monoterpenes, sesquiterpenes, and toluene+p-cymene concentrations, including a substantial increase just after sunrise at 07:00 local time. Higher photochemical aging (> 10 eq. days) led to a decrease in new SOA formation and a loss of preexisting OA due to heterogeneous oxidation followed by fragmentation and volatilization. When comparing two different commonly used methods of OH production in OFRs (OFR185 and OFR254-70), similar amounts of SOA formation were observed. We recommend the OFR185 mode for future forest studies. Concurrent gas-phase measurements of air after OH oxidation illustrate the decay of primary VOCs, production of small oxidized organic compounds, and net production at lower ages followed by net consumption of terpenoid oxidation products as photochemical age increased. New particle formation was observed in the reactor after oxidation, especially during times when precursor gas concentrations and SOA formation were largest. Approximately 4.4 times more SOA was formed in the reactor from OH oxidation than could be explained by the VOCs measured in ambient air. To our knowledge this is the first time that this has been shown when comparing VOC concentrations with SOA formation measured at the same time, rather than comparing measurements made at different times. Several recently developed instruments have quantified ambient semivolatile and intermediate-volatility organic compounds (S/IVOCs) that were not detected by a proton transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS). An SOA yield of 18-58 % from those compounds can explain the observed SOA formation. S/IVOCs were the only pool of gas-phase carbon that was large enough to explain the observed SOA formation. This work suggests that these typically unmeasured gases play a substantial role in ambient SOA formation. Our results allow ruling out condensation sticking coefficients much lower than 1. These measurements help clarify the magnitude of potential SOA formation from OH oxidation in forested environments and demonstrate methods for interpretation of ambient OFR measurements.

Solar nebula chemistry - Implications for volatiles in the solar system

NASA Technical Reports Server (NTRS)

Fegley, Bruce, Jr.; Prinn, Ronald G.

1989-01-01

Current theoretical models of solar nebula chemistry which take into account the interplay between chemistry and dynamics are presented for the abundant reactive volatile elements including hydrogen, carbon, nitrogen, oxygen, and sulfur. Results of these models indicate that, in the solar nebula, the dominant carbon and nitrogen gases were CO and NO, whereas, in giant planet subnebulae, the dominant carbon and nitrogen gases were CH4 and NH3; in the solar nebula, the Fe metal grains catalyzed the formation of organic compounds from CO and H2 via the Fischer-Tropsch-type reaction. It was also found that, in solar nebula, bulk FeS formation was kinetically favorable, while FeO incorporation into silicates and bulk Fe3O4 formation were kinetically inhibited. Furthermore, clathrate formation was kinetically inhibited in the solar nebula, while it was kinetically favorable in giant planet subnebulae.

Down-regulation of SlIAA15 in tomato altered stem xylem development and production of volatile compounds in leaf exudates.

PubMed

Deng, Wei; Yan, Fang; Liu, Minchun; Wang, Xinyu; Li, Zhengguo

2012-08-01

The Aux/IAA family genes encode short-lived nuclear proteins that function as transcriptional regulators in auxin signal transduction. Aux/IAA genes have been reported to control many processes of plant development. Our recent study showed that down-regulation of SlIAA15 in tomato reduced apical dominance, altered pattern of axillary shoot development, increased lateral root formation and leaves thickness. The SlIAA15 suppressed lines display strong reduction of trichome density, suggesting that SlIAA15 is involved in trichome formation. Here, we reported that SlIAA15-suppressed transgenic lines display increased number of xylem cells compared to wild-type plants. Moreover, the monoterpene content in trichome exudates are significantly reduced in SlIAA15 down-regulated leaves. The results provide the roles of SlIAA15 in production of volatile compounds in leaf exudates and xylem development, clearly indicating that members of the Aux/IAA gene family can play distinct and specific functions. 

Fluorescent Polystyrene Films for the Detection of Volatile Organic Compounds Using the Twisted Intramolecular Charge Transfer Mechanism.

PubMed

Borelli, Mirko; Iasilli, Giuseppe; Minei, Pierpaolo; Pucci, Andrea

2017-08-06

Thin films of styrene copolymers containing fluorescent molecular rotors were demonstrated to be strongly sensitive to volatile organic compounds (VOCs). Styrene copolymers of 2-[4-vinyl(1,1'-biphenyl)-4'-yl]-cyanovinyljulolidine (JCBF) were prepared with different P(STY- co -JCBF)(m) compositions (m% = 0.10-1.00) and molecular weights of about 12,000 g/mol. Methanol solutions of JCBF were not emissive due to the formation of the typical twisted intramolecular charge transfer (TICT) state at low viscosity regime, which formation was effectively hampered by adding progressive amounts of glycerol. The sensing performances of the spin-coated copolymer films (thickness of about 4 µm) demonstrated significant vapochromism when exposed to VOCs characterized by high vapour pressure and favourable interaction with the polymer matrix such as THF, CHCl₃ and CH₂Cl₂. The vapochromic response was also reversible and reproducible after successive exposure cycles, whereas the fluorescence variation scaled linearly with VOC concentration, thus suggesting future applications as VOC optical sensors.

Phenotypic responses to microbial volatiles render a mold fungus more susceptible to insect damage.

PubMed

Caballero Ortiz, Silvia; Trienens, Monika; Pfohl, Katharina; Karlovsky, Petr; Holighaus, Gerrit; Rohlfs, Marko

2018-04-01

In decomposer systems, fungi show diverse phenotypic responses to volatile organic compounds of microbial origin (volatiles). The mechanisms underlying such responses and their consequences for the performance and ecological success of fungi in a multitrophic community context have rarely been tested explicitly. We used a laboratory-based approach in which we investigated a tripartite yeast-mold-insect model decomposer system to understand the possible influence of yeast-borne volatiles on the ability of a chemically defended mold fungus to resist insect damage. The volatile-exposed mold phenotype (1) did not exhibit protein kinase A-dependent morphological differentiation, (2) was more susceptible to insect foraging activity, and (3) had reduced insecticidal properties. Additionally, the volatile-exposed phenotype was strongly impaired in secondary metabolite formation and unable to activate "chemical defense" genes upon insect damage. These results suggest that volatiles can be ecologically important factors that affect the chemical-based combative abilities of fungi against insect antagonists and, consequently, the structure and dynamics of decomposer communities.

Novel insight on photochemistry at interfaces: potential impact on Seconday Aerosol Formation?

NASA Astrophysics Data System (ADS)

Rossignol, S.; George, C.; Aregahegn, K.

2014-12-01

Traditionally, the driving forces for SOA growth is believed to be the partitioning onto aerosol seeds of condensable gases, either emitted primarily or resulting from the gas phase oxidation of organic gases. However, even the most up-to-date models based on such mechanisms cannot account for the SOA mass observed in the atmosphere, suggesting the existence of other, yet unknown formation processes. The present study shows experimental evidence that particulate phase chemistry produces photo-sensitizers that lead to photo-induced formation and growth of secondary organic aerosol in the near UV and the presence of volatile organic compounds (VOC) such as terpenes. By means of an aerosol flow tube reactor equipped with Scanning Mobility Particle Sizer (SMPS), Differential Mobility Analyzer (DMA) and Condensation Particle Sizer (CPC), we identified that traces in the aerosol phase of glyoxal chemistry products, namely imidazole-2-carboxaldehyde (IC) are strong photo-sensitizers when irradiated with near-UV. In the presence of volatile organic compounds such as terpenes, this chemistry leads to a fast aerosol growth. Given the potential importance of this new photosensitized growth pathway for ambient OA, the related reaction mechanism was investigated at a molecular level. Bulk and flow tube experiments were performed to identify major products of the reaction of limonene with the triplet state of IC by direct (+/-)ESI-HRMS and UPLC/(+/-)HESI-HRMS analysis. Detection of recombination products of IC with limonene or with itself, in bulk and flow tube experiment ts, showed that IC is able to initiate a radical chemistry in the aerosol phase under realistic irradiation conditions. Furthermore, highly oxygenated limonene reaction products were detected, clearly explaining the observed OA growth. The chemistry of peroxy radicals derived from limonene upon addition of oxygen explains the formation of such low-volatile compounds without any traditional gas phase oxidant. These results demonstrate that, upon ageing, organic aerosols can produce photo-sensitizers which auto-photo-catalyse their SOA growth.

Screening of ground water samples for volatile organic compounds using a portable gas chromatograph

USGS Publications Warehouse

Buchmiller, R.C.

1989-01-01

A portable gas chromatograph was used to screen 32 ground water samples for volatile organic compounds. Seven screened samples were positive; four of the seven samples had volatile organic substances identified by second-column confirmation. Four of the seven positive, screened samples also tested positive in laboratory analyses of duplicate samples. No volatile organic compounds were detected in laboratory analyses of samples that headspace screening indicated to be negative. Samples that contained volatile organic compounds, as identified by laboratory analysis, and that contained a volatile organic compound present in a standard of selected compounds were correctly identified by using the portable gas chromatography. Comparisons of screened-sample data with laboratory data indicate the ability to detect selected volatile organic compounds at concentrations of about 1 microgram per liter in the headspace of water samples by use of a portable gas chromatography. -Author

User's guide for polyethylene-based passive diffusion bag samplers to obtain volatile organic compound concentrations in wells. Part I, Deployment, recovery, data interpretation, and quality control and assurance

USGS Publications Warehouse

Vroblesky, Don A.

2001-01-01

Diffusion samplers installed in observation wells were found to be capable of yielding representative water samples for chlorinated volatile organic compounds. The samplers consisted of polyethylene bags containing deionized water and relied on diffusion of chlorinated volatile organic compounds through the polyethylene membrane. The known ability of polyethylene to transmit other volatile compounds, such as benzene and toluene, indicates that the samplers can be used for a variety of volatile organic compounds. In wells at the study area, the volatile organic compound concentrations in water samples obtained using the samplers without prior purging were similar to concentrations in water samples obtained from the respective wells using traditional purging and sampling approaches. The low cost associated with this approach makes it a viable option for monitoring large observation-well networks for volatile organic compounds.

User's guide for polyethylene-based passive diffusion bag samplers to obtain volatile organic compound concentrations in wells. Part 2, Field tests

USGS Publications Warehouse

Vroblesky, Don A.

2001-01-01

Diffusion samplers installed in observation wells were found to be capable of yielding representative water samples for chlorinated volatile organic compounds. The samplers consisted of polyethylene bags containing deionized water and relied on diffusion of chlorinated volatile organic compounds through the polyethylene membrane. The known ability of polyethylene to transmit other volatile compounds, such as benzene and toluene, indicates that the samplers can be used for a variety of volatile organic compounds. In wells at the study area, the volatile organic compound concentrations in water samples obtained using the samplers without prior purging were similar to concentrations in water samples obtained from the respective wells using traditional purging and sampling approaches. The low cost associated with this approach makes it a viable option for monitoring large observation-well networks for volatile organic compounds.

Investigation of atmospheric pressure capillary non-thermal plasmas and their applications to the degradation of volatile organic compounds

NASA Astrophysics Data System (ADS)

Yin, Shu-Min

Atmospheric pressure capillary non-thermal plasma (AP-CNTP) has been investigated as a potential technology far the removal of volatile organic compounds (VOCs) in Advanced Life Support Systems (ALS). AP-CNTP is a destructive technology far the removal of VOCs from air streams by active plasma species, such as electrons, ions, and excited molecules. Complete VOC destruction ideally results in the formation of water, carbon dioxide (CO2), and other by-product's may also form, including ozone (O3), nitrous oxide (N2O), nitrogen dioxide (NO2), and decomposed hydrocarbons. Several organic compounds, such as BTEX, ethylene, n-heptane, isooctane, methanol and NH3, were tested in an AP-CNTP system. Parametric experiments were carried out by varying plasma discharge power, flowrates, and initial concentrations. The degradation efficiency varied depending on the chemical nature of the compounds. A plasmochemical kinetic model was derived for toluene, ethylbenzene, and m-xylene and n-heptane.

Methanol ice VUV photoprocessing: GC-MS analysis of volatile organic compounds

NASA Astrophysics Data System (ADS)

Abou Mrad, Ninette; Duvernay, Fabrice; Chiavassa, Thierry; Danger, Grégoire

2016-05-01

Next to water, methanol is one of the most abundant molecules in astrophysical ices. A new experimental approach is presented here for the direct monitoring via gas chromatography coupled to mass spectrometry (GC-MS) of a sublimating photoprocessed pure methanol ice. Unprecedentedly, in a same analysis, compelling evidences for the formation of 33 volatile organic compounds are provided. The latter are C1-C6 products including alcohols, aldehydes, ketones, esters, ethers and carboxylic acids. Few C3 and all C4 detected compounds have been identified for the first time. Tentative detections of few C5 and C6 compounds are also presented. GC-MS allows for the first time the direct quantification of C2-C4 photoproducts and shows that their abundances decrease with the increase of their carbon chain length. These qualitative and quantitative measurements provide important complementary results to previous experiments, and present interesting similarities with observations of sources rich in methanol.

Effect of mesophilic lactobacilli and enterococci adjunct cultures on the final characteristics of a microfiltered milk Swiss-type cheese.

PubMed

Bouton, Yvette; Buchin, Solange; Duboz, Gabriel; Pochet, Sylvie; Beuvier, Eric

2009-04-01

The effect of four associations of adjunct cultures composed of mesophilic lactobacilli and enterococci, either solely or combined, on the microbiological, biochemical and sensory characteristics of Swiss-type cheese made using microfiltered cows' milk and supplemented with propionibacteria was studied. The global pattern of growth was similar to that generally observed in raw milk cheese and interactions between microflora were highlighted during ripening. Enterococci, which negatively affected the survival of streptococci starters, seemed to play a limited role in the formation of volatile compounds, probably due to their low levels throughout ripening. On the contrary, mesophilic lactobacilli, which affected the evolution of propionibacteria, enterococci and L. delbrueckii subsp. lactis starter counts, modified free amino acid content, production of volatile compounds and organoleptic properties of mature cheese. This population appeared to be of major importance in the formation of cheese flavor as it was positively related to numerous potential flavor compounds such as alcohols and their corresponding esters, acetaldehyde and 4-methyl-4-heptanone. The original mesophilic lactobacilli present in milk could play an important role in the sensorial diversity of raw milk Swiss-type cheeses such as Comte.

Inorganic salts interact with oxalic acid in submicron particles to form material with low hygroscopicity and volatility

NASA Astrophysics Data System (ADS)

Drozd, G.; Woo, J.; Häkkinen, S. A. K.; Nenes, A.; McNeill, V. F.

2014-05-01

Volatility and hygroscopicity are two key properties of organic aerosol components, and both are strongly related to chemical identity. While the hygroscopicities of pure salts, di-carboxylic acids (DCA), and DCA salts are known, the hygroscopicity of internal mixtures of these components, as they are typically found in the atmosphere, has not been fully characterized. Here we show that inorganic-organic component interactions typically not considered in atmospheric models can lead to very strongly bound metal-organic complexes and greatly affect aerosol volatility and hygroscopicity; in particular, the bi-dentate binding of DCA to soluble inorganic ions. We have studied the volatility of pure, dry organic salt particles and the hygroscopicity of internal mixtures of oxalic acid (OxA, the dominant DCA in the atmosphere) and a number of salts, both mono- and di-valent. The formation of very low volatility organic salts was confirmed, with minimal evaporation of oxalate salt particles below 75 °C. Dramatic increases in the cloud condensation nuclei (CCN) activation diameter for particles with di-valent salts (e.g., CaCl2) and relatively small particle volume fractions of OxA indicate that standard volume additivity rules for hygroscopicity do not apply. Thus small organic compounds with high O : C ratios are capable of forming low-volatility and very low hygroscopicity particles. Given current knowledge of the formation mechanisms of OxA and M-Ox salts, surface enrichment of insoluble M-Ox salts is expected. The resulting formation of an insoluble coating of metal-oxalate salts can explain low-particle hygroscopicities. The formation of particles with a hard coating could offer an alternative explanation for observations of glass-like particles without the need for a phase transition.

Contribution of sulfur-containing compounds to the colour-inhibiting effect and improved antioxidant activity of Maillard reaction products of soybean protein hydrolysates.

PubMed

Huang, Meigui; Liu, Ping; Song, Shiqing; Zhang, Xiaoming; Hayat, Khizar; Xia, Shuqin; Jia, Chengsheng; Gu, Fenglin

2011-03-15

Light-coloured and savoury-tasting flavour enhancers are attractive to both consumers and food producers. The aim of this study was to investigate the colour-inhibiting effect of L-cysteine and thiamine during the Maillard reaction of soybean peptide and D-xylose. The correlation between volatile compounds and antioxidant activity of the corresponding products was also studied. Colour formation was markedly suppressed by cysteine. Compared with peptide/xylose (PX), the taste profile of Maillard reaction products (MRPs) derived from peptide/xylose/cysteine (PXC) and peptide/xylose/cysteine/thiamine (PXCT) was stronger, including umami, mouthfulness, continuity, meaty and overall acceptance. PXC and PXCT also exihibited distinctly higher antioxidant activity. Principal component analysis was applied to investigate the correlation between antioxidant activity and volatile compounds. Of 88 volatile compounds identified, 55 were significantly correlated with antioxidant activity by two principal components (accounting for 85.05% of the total variance). Effective colour control of the Maillard reaction by L-cysteine may allow the production of healthier (higher antioxidant activity) and tastier foods to satisfy consumers' and food producers' demands. Light-coloured products might be used as functional flavour enhancers in various food systems. Copyright © 2010 Society of Chemical Industry.

Effect of roasting conditions on color and volatile profile including HMF level in sweet almonds (Prunus dulcis).

PubMed

Agila, Amal; Barringer, Sheryl

2012-04-01

Microwave, oven, and oil roasting of almonds were used to promote almond flavor and color formation. Raw pasteurized almonds were roasted in a microwave for 1 to 3 min, in an oven at 177 °C for 5, 10, 15, and 20 min; and at 135 and 163 °C for 20 min, and in oil at 135, 163, and 177 °C for 5 min and 177 °C for 10 min. Volatile compounds were quantified in the headspace of ground almonds, both raw and roasted, by selected ion flow tube mass spectrometry. Strong correlations were found between L value, chroma, and 5-(hydroxy methyl)-2- furfural; and were independent of roasting method. Raw almonds had lower concentrations of most volatiles than roasted almonds. Conditions that produced color equivalent to commercial samples were 2 min in the microwave, 5 min at 177 °C in the oven, and 5 min at 135 °C in oil. Microwave heating produced higher levels of most volatiles than oven and oil roasting at commercial color. Sensory evaluation indicated that microwave-roasted almonds had the strongest aroma and were the most preferred. Oil-roasted almonds showed significantly lower levels of volatiles than other methods, likely due to loss of these volatiles into the oil. Alcohols such as benzyl alcohols and strecker aldehydes including benzaldehyde and methional were at higher concentrations than other volatiles in roasted almonds. The oxidation of lipids to form alkanals such as nonanal and degradation of sugars to form furan type compounds was also observed. The Maillard reaction contributed to the formation of more of the total volatiles in almonds than the lipid oxidation reaction. The level of 5-(hydroxy methyl)-2- furfural (HMF), color, volatile profile, and sensory perception can be used to develop the best roasting method, time, and temperature for almonds. The rate of color development and the production of volatiles differ under different roasting conditions. Based on the color, volatile, and sensory assessments of the 3 almonds, the use of microwave technology as a process for roasting almonds reduces processing time and leads to an almond product with better flavor than oven or oil roasting. © 2012 Institute of Food Technologists®

VOLATILE ORGANIC COMPOUND EMISSIONS FROM 46 IN-USE PASSENGER CARS

EPA Science Inventory

Emissions from automobiles have long been considered a prime source of pollutants involved in smog formation and ozone production. The reactive potential of the species emitted has been studied extensively, and many reactivity schemes have been proposed. Most of the data on the d...

Limited effect of anthropogenic nitrogen oxides on Secondary Organic Aerosol formation

NASA Astrophysics Data System (ADS)

Zheng, Y.; Unger, N.; Hodzic, A.; Emmons, L.; Knote, C.; Tilmes, S.; Lamarque, J.-F.; Yu, P.

2015-08-01

Globally, secondary organic aerosol (SOA) is mostly formed from emissions of biogenic volatile organic compounds (VOCs) by vegetation, but can be modified by human activities as demonstrated in recent research. Specifically, nitrogen oxides (NOx = NO + NO2) have been shown to play a critical role in the chemical formation of low volatility compounds. We have updated the SOA scheme in the global NCAR Community Atmospheric Model version 4 with chemistry (CAM4-chem) by implementing a 4-product Volatility Basis Set (VBS) scheme, including NOx-dependent SOA yields and aging parameterizations. The predicted organic aerosol amounts capture both the magnitude and distribution of US surface annual mean measurements from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network by 50 %, and the simulated vertical profiles are within a factor of two compared to Aerosol Mass Spectrometer (AMS) measurements from 13 aircraft-based field campaigns across different region and seasons. We then perform sensitivity experiments to examine how the SOA loading responds to a 50 % reduction in anthropogenic nitric oxide (NO) emissions in different regions. We find limited SOA reductions of 0.9 to 5.6, 6.4 to 12.0 and 0.9 to 2.8 % for global, the southeast US and the Amazon NOx perturbations, respectively. The fact that SOA formation is almost unaffected by changes in NOx can be largely attributed to buffering in chemical pathways (low- and high-NOx pathways, O3 versus NO3-initiated oxidation) and to offsetting tendencies in the biogenic versus anthropogenic SOA responses.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hodshire, Anna L.; Lawler, Michael J.; Zhao, Jun

New-particle formation (NPF) is a significant source of aerosol particles into the atmosphere. However, these particles are initially too small to have climatic importance and must grow, primarily through net uptake of low-volatility species, from diameters  ∼  1 to 30–100 nm in order to potentially impact climate. There are currently uncertainties in the physical and chemical processes associated with the growth of these freshly formed particles that lead to uncertainties in aerosol-climate modeling. Four main pathways for new-particle growth have been identified: condensation of sulfuric-acid vapor (and associated bases when available), condensation of organic vapors, uptake of organic acids through acid–base chemistrymore » in the particle phase, and accretion of organic molecules in the particle phase to create a lower-volatility compound that then contributes to the aerosol mass. The relative importance of each pathway is uncertain and is the focus of this work. The 2013 New Particle Formation Study (NPFS) measurement campaign took place at the DOE Southern Great Plains (SGP) facility in Lamont, Oklahoma, during spring 2013. Measured gas- and particle-phase compositions during these new-particle growth events suggest three distinct growth pathways: (1) growth by primarily organics, (2) growth by primarily sulfuric acid and ammonia, and (3) growth by primarily sulfuric acid and associated bases and organics. To supplement the measurements, we used the particle growth model MABNAG (Model for Acid–Base chemistry in NAnoparticle Growth) to gain further insight into the growth processes on these 3 days at SGP. MABNAG simulates growth from (1) sulfuric-acid condensation (and subsequent salt formation with ammonia or amines), (2) near-irreversible condensation from nonreactive extremely low-volatility organic compounds (ELVOCs), and (3) organic-acid condensation and subsequent salt formation with ammonia or amines. MABNAG is able to corroborate the observed differing growth pathways, while also predicting that ELVOCs contribute more to growth than organic salt formation. However, most MABNAG model simulations tend to underpredict the observed growth rates between 10 and 20 nm in diameter; this underprediction may come from neglecting the contributions to growth from semi-to-low-volatility species or accretion reactions. Our results suggest that in addition to sulfuric acid, ELVOCs are also very important for growth in this rural setting. We discuss the limitations of our study that arise from not accounting for semi- and low-volatility organics, as well as nitrogen-containing species beyond ammonia and amines in the model. Quantitatively understanding the overall budget, evolution, and thermodynamic properties of lower-volatility organics in the atmosphere will be essential for improving global aerosol models.« less

Influence of physicochemical parameters and high pressure processing on the volatile compounds of Serrano dry-cured ham after prolonged refrigerated storage.

PubMed

Martínez-Onandi, N; Rivas-Cañedo, A; Picon, A; Nuñez, M

2016-12-01

One hundred and three volatile compounds were detected by solid-phase microextraction followed by gas chromatography-mass spectrometry in 30 ripened Serrano dry-cured hams, submitted or not to high pressure processing (HPP) and afterwards held for 5months at 4°C. The effect of ham physicochemical parameters and HPP (600MPa for 6min) on volatile compounds was assessed. Physicochemical parameters primarily affected the levels of acids, alcohols, alkanes, esters, benzene compounds, sulfur compounds and some miscellaneous compounds. Intramuscular fat content was the physicochemical parameter with the most pronounced effect on the volatile fraction of untreated Serrano ham after refrigerated storage, influencing the levels of 38 volatile compounds while aw, salt content and salt-in-lean ratio respectively influenced the levels of 4, 4 and 5 volatile compounds. HPP treatment affected 21 volatile compounds, resulting in higher levels of alkanes and ketones and lower levels of esters and secondary alcohols, what might affect Serrano ham odor and aroma after 5months of refrigerated storage. Copyright © 2016 Elsevier Ltd. All rights reserved.

Volatile and non-volatile/semi-volatile compounds and in vitro bioactive properties of Chilean Ulmo (Eucryphia cordifolia Cav.) honey.

PubMed

Acevedo, Francisca; Torres, Paulina; Oomah, B Dave; de Alencar, Severino Matias; Massarioli, Adna Prado; Martín-Venegas, Raquel; Albarral-Ávila, Vicenta; Burgos-Díaz, César; Ferrer, Ruth; Rubilar, Mónica

2017-04-01

Ulmo honey originating from Eucryphia cordifolia tree, known locally in the Araucania region as the Ulmo tree is a natural product with valuable nutritional and medicinal qualities. It has been used in the Mapuche culture to treat infections. This study aimed to identify the volatile and non-volatile/semi-volatile compounds of Ulmo honey and elucidate its in vitro biological properties by evaluating its antioxidant, antibacterial, antiproliferative and hemolytic properties and cytotoxicity in Caco-2 cells. Headspace volatiles of Ulmo honey were isolated by solid-phase microextraction (SPME); non-volatiles/semi-volatiles were obtained by removing all saccharides with acidified water and the compounds were identified by GC/MS analysis. Ulmo honey volatiles consisted of 50 compounds predominated by 20 flavor components. Two of the volatile compounds, lyrame and anethol have never been reported before as honey compounds. The non-volatile/semi-volatile components of Ulmo honey comprised 27 compounds including 13 benzene derivatives accounting 75% of the total peak area. Ulmo honey exhibited weak antioxidant activity but strong antibacterial activity particularly against gram-negative bacteria and methicillin-resistant Staphylococcus aureus (MRSA), the main strain involved in wounds and skin infections. At concentrations >0.5%, Ulmo honey reduced Caco-2 cell viability, released lactate dehydrogenase (LDH) and increased reactive oxygen species (ROS) production in a dose dependent manner in the presence of foetal bovine serum (FBS). The wide array of volatile and non-volatile/semi-volatile constituents of Ulmo honey rich in benzene derivatives may partly account for its strong antibacterial and antiproliferative properties important for its therapeutic use. Our results indicate that Ulmo honey can potentially inhibit cancer growth at least partly by modulating oxidative stress. Copyright © 2017 Elsevier Ltd. All rights reserved.

Characterization by volatile compounds of microbial deep spoilage in Iberian dry-cured ham.

PubMed

Martín, Alberto; Benito, María J; Aranda, Emilio; Ruiz-Moyano, Santiago; Córdoba, Juan J; Córdoba, María G

2010-08-01

In the present study, volatile compounds of spoiled dry-cured Iberian ham with deep spoilage or "bone taint" were analyzed and correlated with level of spoilage and the microorganisms detected. Volatile compounds extracted by a solid phase micro-extraction technique were assayed by gas chromatography/mass spectrometry. The spoiled hams were evaluated sensorially, and the correlations among volatile compounds, spoilage level, and microbial counts were studied. The spoiled hams had higher concentrations of hydrocarbons, alcohols, acids, esters, pyrazines, sulfur compounds, and other minor volatile compounds than unspoiled hams. The sensorial analysis showed that the spoilage level of hams correlated with several volatile compounds, most of them associated with Gram-positive catalase positive cocci and Enterobacteriaceae counts. Cyclic compounds such as cyclohexanone, some ethers, and pyrazines should be considered as indicators to monitor incipient microbial deep spoilage in the elaboration of this meat product.

Formation and aging of secondary organic aerosol from toluene: Changes in chemical composition, volatility, and hygroscopicity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hildebrandt Ruiz, L.; Paciga, A. L.; Cerully, K. M.

Secondary organic aerosol (SOA) is transformed after its initial formation, but this chemical aging of SOA is poorly understood. Experiments were conducted in the Carnegie Mellon environmental chamber to form secondary organic aerosol (SOA) from the photo-oxidation of toluene and other small aromatic volatile organic compounds (VOCs) in the presence of NO x under different oxidizing conditions. The effects of the oxidizing condition on organic aerosol (OA) composition, mass yield, volatility, and hygroscopicity were explored. Higher exposure to the hydroxyl radical resulted in different OA composition, average carbon oxidation state (OS c), and mass yield. The OA oxidation state generallymore » increased during photo-oxidation, and the final OA OS c ranged from –0.29 to 0.16 in the performed experiments. The volatility of OA formed in these different experiments varied by as much as a factor of 30, demonstrating that the OA formed under different oxidizing conditions can have a significantly different saturation concentration. In conclusion, there was no clear correlation between hygroscopicity and oxidation state for this relatively hygroscopic SOA.« less

Formation and aging of secondary organic aerosol from toluene: Changes in chemical composition, volatility, and hygroscopicity

DOE PAGES

Hildebrandt Ruiz, L.; Paciga, A. L.; Cerully, K. M.; ...

2015-07-24

Secondary organic aerosol (SOA) is transformed after its initial formation, but this chemical aging of SOA is poorly understood. Experiments were conducted in the Carnegie Mellon environmental chamber to form secondary organic aerosol (SOA) from the photo-oxidation of toluene and other small aromatic volatile organic compounds (VOCs) in the presence of NO x under different oxidizing conditions. The effects of the oxidizing condition on organic aerosol (OA) composition, mass yield, volatility, and hygroscopicity were explored. Higher exposure to the hydroxyl radical resulted in different OA composition, average carbon oxidation state (OS c), and mass yield. The OA oxidation state generallymore » increased during photo-oxidation, and the final OA OS c ranged from –0.29 to 0.16 in the performed experiments. The volatility of OA formed in these different experiments varied by as much as a factor of 30, demonstrating that the OA formed under different oxidizing conditions can have a significantly different saturation concentration. In conclusion, there was no clear correlation between hygroscopicity and oxidation state for this relatively hygroscopic SOA.« less

Effect of chitosan-lemon essential oil coatings on volatile profile of strawberries during storage.

PubMed

Perdones, Ángela; Escriche, Isabel; Chiralt, Amparo; Vargas, Maria

2016-04-15

Chitosan coatings containing lemon essential oils were described as effective at controlling fruit fungal decay at 20°C during 7 days. In this work, GC-MS was used to characterise the volatile compounds of strawberries during cold storage in order to analyse the influence of fruit coatings with chitosan, containing or not containing lemon essential oil, on the volatile profile of the fruits. The coatings affected the metabolic pathways and volatile profile of the fruits. Pure chitosan promoted the formation of esters and dimethyl furfural in very short time after coating, while coatings containing lemon essential oil incorporated terpenes (limonene, γ-terpinene, p-cymene and α-citral) to the fruit volatiles and enhanced the fermentative process, modifying the typical fruit aroma composition. No effect of chitosan coatings was sensorially perceived, the changes induced by lemon essential oil were notably appreciated. Copyright © 2015 Elsevier Ltd. All rights reserved.

Volatilization and precipitation of tellurium by aerobic, tellurite-resistant marine microbes.

PubMed

Ollivier, Patrick R L; Bahrou, Andrew S; Marcus, Sarah; Cox, Talisha; Church, Thomas M; Hanson, Thomas E

2008-12-01

Microbial resistance to tellurite, an oxyanion of tellurium, is widespread in the biosphere, but the geochemical significance of this trait is poorly understood. As some tellurite resistance markers appear to mediate the formation of volatile tellurides, the potential contribution of tellurite-resistant microbial strains to trace element volatilization in salt marsh sediments was evaluated. Microbial strains were isolated aerobically on the basis of tellurite resistance and subsequently examined for their capacity to volatilize tellurium in pure cultures. The tellurite-resistant strains recovered were either yeasts related to marine isolates of Rhodotorula spp. or gram-positive bacteria related to marine strains within the family Bacillaceae based on rRNA gene sequence comparisons. Most strains produced volatile tellurides, primarily dimethyltelluride, though there was a wide range of the types and amounts of species produced. For example, the Rhodotorula spp. produced the greatest quantities and highest diversity of volatile tellurium compounds. All strains also produced methylated sulfur compounds, primarily dimethyldisulfide. Intracellular tellurium precipitates were a major product of tellurite metabolism in all strains tested, with nearly complete recovery of the tellurite initially provided to cultures as a precipitate. Different strains appeared to produce different shapes and sizes of tellurium containing nanostructures. These studies suggest that aerobic marine yeast and Bacillus spp. may play a greater role in trace element biogeochemistry than has been previously assumed, though additional work is needed to further define and quantify their specific contributions.

Effects of temperature on the production of hydrogen peroxide and volatile halocarbons by brackish-water algae.

PubMed

Abrahamsson, Katarina; Choo, Kyung Sil; Pedersén, Marianne; Johansson, Gustav; Snoeijs, Pauli

2003-10-01

Marine algae produce volatile halocarbons, which have an ozone-depleting potential. The formation of these compounds is thought to be related to oxidative stress, involving H2O2 and algal peroxidases. In our study we found strong correlations between the releases of H2O2 and brominated and some iodinated compounds to the seawater medium, but no such correlation was found for CHCl3, suggesting the involvement of other formation mechanisms as well. Little is known about the effects of environmental factors on the production of volatile halocarbons by algae and in the present study we focused on the influence of temperature. Algae were sampled in an area of the brackish Baltic Sea that receives thermal discharge, allowing us to collect specimens of the same species that were adapted to different field temperature regimes. We exposed six algal species (the diatom Pleurosira laevis, the brown alga Fucus vesiculosus and four filamentous green algae, Cladophora glomerata, Enteromorpha ahlneriana, E. flexuosa and E. intestinalis) to temperature changes of 0-11 degrees C under high irradiation to invoke oxidative stress. The production rates, as well as the quantitative composition of 16 volatile halocarbons, were strongly species-dependent and different types of responses to temperature were recorded. However, no response patterns to temperature change were found that were consistent for all species or for all halocarbons. We conclude that the production of certain halocarbons may increase with temperature in certain algal species, but that the amount and composition of the volatile halocarbons released by algal communities are probably more affected by temperature-associated species shifts. These results may have implications for climatic change scenarios.

Electric-field triggered controlled release of bioactive volatiles from imine-based liquid crystalline phases.

PubMed

Herrmann, Andreas; Giuseppone, Nicolas; Lehn, Jean-Marie

2009-01-01

Application of an electric field to liquid crystalline film forming imines with negative dielectric anisotropy, such as N-(4-methoxybenzylidene)-4-butylaniline (MBBA, 1), results in the expulsion of compounds that do not participate in the formation of the liquid crystalline phase. Furthermore, amines and aromatic aldehydes undergo component exchange with the imine by generating constitutional dynamic libraries. The strength of the electric field and the duration of its application to the liquid crystalline film influence the release rate of the expelled compounds and, at the same time, modulate the equilibration of the dynamic libraries. The controlled release of volatile organic molecules with different chemical functionalities from the film was quantified by dynamic headspace analysis. In all cases, higher headspace concentrations were detected in the presence of an electric field. These results point to the possibility of using imine-based liquid crystalline films to build devices for the controlled release of a broad variety of bioactive volatiles as a direct response to an external electric signal.

Language of plants: Where is the word?

PubMed

Šimpraga, Maja; Takabayashi, Junji; Holopainen, Jarmo K

2016-04-01

Plants emit biogenic volatile organic compounds (BVOCs) causing transcriptomic, metabolomic and behavioral responses in receiver organisms. Volatiles involved in such responses are often called "plant language". Arthropods having sensitive chemoreceptors can recognize language released by plants. Insect herbivores, pollinators and natural enemies respond to composition of volatiles from plants with specialized receptors responding to different types of compounds. In contrast, the mechanism of how plants "hear" volatiles has remained obscured. In a plant-plant communication, several individually emitted compounds are known to prime defense response in receiver plants with a specific manner according to the chemical structure of each volatile compound. Further, composition and ratio of volatile compounds in the plant-released plume is important in plant-insect and plant-plant interactions mediated by plant volatiles. Studies on volatile-mediated plant-plant signaling indicate that the signaling distances are rather short, usually not longer than one meter. Volatile communication from plants to insects such as pollinators could be across distances of hundreds of meters. As many of the herbivore induced VOCs have rather short atmospheric life times, we suggest that in long-distant communications with plant volatiles, reaction products in the original emitted compounds may have additional information value of the distance to emission source together with the original plant-emitted compounds. © 2015 Institute of Botany, Chinese Academy of Sciences.

75 FR 60013 - Approval and Promulgation of Air Quality Implementation Plans; Maryland; Control of Volatile...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-29

... Promulgation of Air Quality Implementation Plans; Maryland; Control of Volatile Organic Compounds Emissions... Maryland's Volatile Organic Compounds from Specific Processes Regulation. Maryland has adopted standards... (RACT) requirements for sources of volatile organic compounds (VOCs) covered by control techniques...

Modeling SOA formation from the oxidation of intermediate volatility n-alkanes

NASA Astrophysics Data System (ADS)

Aumont, B.; Valorso, R.; Mouchel-Vallon, C.; Camredon, M.; Lee-Taylor, J.; Madronich, S.

2012-08-01

The chemical mechanism leading to SOA formation and ageing is expected to be a multigenerational process, i.e. a successive formation of organic compounds with higher oxidation degree and lower vapor pressure. This process is here investigated with the explicit oxidation model GECKO-A (Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere). Gas phase oxidation schemes are generated for the C8-C24 series of n-alkanes. Simulations are conducted to explore the time evolution of organic compounds and the behavior of secondary organic aerosol (SOA) formation for various preexisting organic aerosol concentration (COA). As expected, simulation results show that (i) SOA yield increases with the carbon chain length of the parent hydrocarbon, (ii) SOA yield decreases with decreasing COA, (iii) SOA production rates increase with increasing COA and (iv) the number of oxidation steps (i.e. generations) needed to describe SOA formation and evolution grows when COA decreases. The simulated oxidative trajectories are examined in a two dimensional space defined by the mean carbon oxidation state and the volatility. Most SOA contributors are not oxidized enough to be categorized as highly oxygenated organic aerosols (OOA) but reduced enough to be categorized as hydrocarbon like organic aerosols (HOA), suggesting that OOA may underestimate SOA. Results show that the model is unable to produce highly oxygenated aerosols (OOA) with large yields. The limitations of the model are discussed.

Modeling SOA formation from the oxidation of intermediate volatility n-alkanes

NASA Astrophysics Data System (ADS)

Aumont, B.; Valorso, R.; Mouchel-Vallon, C.; Camredon, M.; Lee-Taylor, J.; Madronich, S.

2012-06-01

The chemical mechanism leading to SOA formation and ageing is expected to be a multigenerational process, i.e. a successive formation of organic compounds with higher oxidation degree and lower vapor pressure. This process is here investigated with the explicit oxidation model GECKO-A (Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere). Gas phase oxidation schemes are generated for the C8-C24 series of n-alkanes. Simulations are conducted to explore the time evolution of organic compounds and the behavior of secondary organic aerosol (SOA) formation for various preexisting organic aerosol concentration (COA). As expected, simulation results show that (i) SOA yield increases with the carbon chain length of the parent hydrocarbon, (ii) SOA yield decreases with decreasing COA, (iii) SOA production rates increase with increasing COA and (iv) the number of oxidation steps (i.e. generations) needed to describe SOA formation and evolution grows when COA decreases. The simulated oxidative trajectories are examined in a two dimensional space defined by the mean carbon oxidation state and the volatility. Most SOA contributors are not oxidized enough to be categorized as highly oxygenated organic aerosols (OOA) but reduced enough to be categorized as hydrocarbon like organic aerosols (HOA), suggesting that OOA may underestimate SOA. Results show that the model is unable to produce highly oxygenated aerosols (OOA) with large yields. The limitations of the model are discussed.

Selenium Assimilation and Volatilization from Dimethylselenoniopropionate by Indian Mustard1

PubMed Central

de Souza, Mark P.; Lytle, C. Mel; Mulholland, Maria M.; Otte, Marinus L.; Terry, Norman

2000-01-01

Earlier work from our laboratory on Indian mustard (Brassica juncea L.) identified the following rate-limiting steps for the assimilation and volatilization of selenate to dimethyl selenide (DMSe): (a) uptake of selenate, (b) activation of selenate by ATP sulfurylase, and (b) conversion of selenomethionine (SeMet) to DMSe. The present study showed that shoots of selenate-treated plants accumulated very low concentrations of dimethylselenoniopropionate (DMSeP). Selenonium compounds such as DMSeP are the most likely precursors of DMSe. DMSeP-supplied plants volatilized Se at a rate 113 times higher than that measured from plants supplied with selenate, 38 times higher than from selenite, and six times higher than from SeMet. The conversion of SeMet to selenonium compounds such as DMSeP is likely to be rate-limiting for DMSe production, but not the formation of DMSe from DMSeP because DMSeP was the rate of Se volatilization from faster than from SeMet and SeMet (but no DMSeP) accumulated in selenite- or SeMet-supplied wild-type plants and in selenate-supplied ATP-sulfurylase transgenic plants. DMSeP-supplied plants absorbed the most Se from the external medium compared with plants supplied with SeMet, selenate, or selenite; they also accumulated more Se in shoots than in roots as an unknown organic compound resembling a mixture of DMSeP and selenocysteine. PMID:10759525

Secondary organic aerosol formation from fossil fuel sources contribute majority of summertime organic mass at Bakersfield

EPA Science Inventory

Secondary organic aerosols (SOA), known to form in the atmosphere from oxidation of volatile organic compounds (VOCs) emitted by anthropogenic and biogenic sources, are a poorly understood but substantial component of atmospheric particles. In this study, we examined the chemic...

Substitution of carcinogenic solvent dichloromethane for the extraction of volatile compounds in a fat-free model food system.

PubMed

Cayot, Nathalie; Lafarge, Céline; Bou-Maroun, Elias; Cayot, Philippe

2016-07-22

Dichloromethane is known as a very efficient solvent, but, as other halogenated solvents, is recognized as a hazardous product (CMR substance). The objective of the present work is to propose substitution solvent for the extraction of volatile compounds. The most important physico-chemical parameters in the choice of an appropriate extraction solvent of volatile compounds are reviewed. Various solvents are selected on this basis and on their hazard characteristics. The selected solvents, safer than dichloromethane, are compared using the extraction efficiency of volatile compounds from a model food product able to interact with volatile compounds. Volatile compounds with different hydrophobicity are used. High extraction yields were positively correlated with high boiling points and high Log Kow values of volatile compounds. Mixtures of solvents such as azeotrope propan-2-one/cyclopentane, azeotrope ethyl acetate/ethanol, and mixture ethyl acetate/ethanol (3:1, v/v) gave higher extraction yields than those obtained with dichloromethane. Copyright © 2016 Elsevier B.V. All rights reserved.

Consumer palatability scores and volatile beef flavor compounds of five USDA quality grades and four muscles.

PubMed

Legako, J F; Brooks, J C; O'Quinn, T G; Hagan, T D J; Polkinghorne, R; Farmer, L J; Miller, M F

2015-02-01

Proximate data, consumer palatability scores and volatile compounds were investigated for four beef muscles (Longissimus lumborum, Psoas major, Semimembranosus and Gluteus medius) and five USDA quality grades(Prime, Upper 2/3 Choice, Low Choice, Select, and Standard). Quality grade did not directly affect consumer scores or volatiles but interactions (P < 0.05) between muscle and grade were determined. Consumer scores and volatiles differed (P < 0.05) between muscles. Consumers scored Psoas major highest for tenderness, juiciness, flavor liking and overall liking, followed by Longissimus lumborum, Gluteus medius, and Semimembranosus (P < 0.05). Principal component analysis revealed clustering of compound classes, formed by related mechanisms. Volatile n-aldehydes were inversely related to percent fat. Increases in lipid oxidation compounds were associated with Gluteus medius and Semimembranosus, while greater quantities of sulfur-containing compounds were associated with Psoas major. Relationships between palatability scores and volatile compound classes suggest that differences in the pattern of volatile compounds may play a valuable role in explaining consumer liking.

Development of volatile compounds during the manufacture of dry-cured "lacón," a Spanish traditional meat product.

PubMed

Purriños, Laura; Bermúdez, Roberto; Franco, Daniel; Carballo, Javier; Lorenzo, José M

2011-01-01

Volatile compounds were determined throughout the manufacture of dry-cured "lacón," a traditional dry-salted, and ripened meat product made in the north-west of Spain from the foreleg of the pig following a similar process to that of dry-cured ham. Volatiles were extracted by a purge-and-trap method and analyzed by gas chromatographic/mass spectrometry. One hundred and two volatile compounds were identified. In raw material, only 34 volatile compounds were found and at very low levels. The number of volatile compounds increased during processing. The substances identified belonged to several chemical classes: aldehydes (23), alcohols (9), ketones (15), hydrocarbons (37), esters (4), acids (3), furans (4), sulphur compounds (1), chloride compounds (1), and other compounds (4). Results indicated that the most abundant chemical family in flavor at the end of the manufacturing process was aldehydes, followed by hydrocarbons and ketones. Lipids were the most important precursor of flavor compounds of dry-cured "lacón."

Water-quality assessment of south-central Texas: Occurrence and distribution of volatile organic compounds in surface water and ground water, 1983-94, and implications for future monitoring

USGS Publications Warehouse

Ging, P.B.; Judd, L.J.; Wynn, K.H.

1997-01-01

The study area of the South-Central Texas study unit of the National Water-Quality Assessment Program comprises the Edwards aquifer in the San Antonio region and its catchment area. The first phase of the assessment includes evaluation of existing water-quality data for surface water and ground water, including volatile organic compounds, to determine the scope of planned monitoring. Most analyses of volatile organic compounds in surface water are from the National Pollutant Discharge Elimination System sites in San Antonio, Texas. Nine volatile organic compounds were detected at the six sites. The three compounds with the most detections at National Pollutant Discharge Elimination System sites are 1,2,4-trimethylbenzene, toluene, and xylene. Analysis of volatile organic compounds in ground water was limited to Edwards aquifer wells. Twenty-eight volatile organic compounds were detected in samples from 89 wells. The five most commonly detected compounds in samples from wells, in descending order, are tetrachloroethene, trichloroethene, bromoform, chloroform, and dibromochloromethane. Detections of volatile organic compounds in surface water and ground water within the South-Central Texas study area are limited to site-specific sources associated with development; therefore, planned monitoring for possible detections of volatile organic compounds as part of the National Water-Quality Assessment Program will emphasize areas of expanding population and development. Monitoring of volatile organic compounds is planned at National Pollutant Discharge Elimination System sites, at basic fixed surface-water sites, and in the ground-water study-unit surveys.

Inorganic salts interact with organic di-acids in sub-micron particles to form material with low hygroscopicity and volatility

NASA Astrophysics Data System (ADS)

Drozd, G.; Woo, J.; Häkkinen, S. A. K.; Nenes, A.; McNeill, V. F.

2013-11-01

Volatility and hygroscopicity are two key properties of organic aerosol components, and both are strongly related to chemical identity. Here we show that inorganic-organic component interactions typically not considered in atmospheric models may strongly affect aerosol volatility and hygroscopicity. In particular, bi-dentate binding of di-carboxylic acids (DCA) to soluble inorganic ions can lead to very strongly bound metal-organic complexes with largely undetermined hygroscopicity and volatility. These reactions profoundly impact particle hygroscopicity, transforming hygroscopic components into irreversibly non-hygroscopic material. While the hygroscopicities of pure salts, DCA, and DCA salts are known, the hygroscopicity of internal mixtures of hygroscopic salts and DCA, as they are typically found in the atmosphere, has not been fully characterized. We have studied the volatility of pure, dry organic salt particles and the hygroscopicity of internal mixtures of oxalic acid (OxA, the dominant DCA in the atmosphere) and a number of salts, both mono- and di-valent. The formation of very low volatility organic salts was confirmed, with minimal evaporation of oxalate salt particles below 75 °C. Dramatic increases in the CCN activation diameter for particles with divalent salts (e.g. CaCl2) and relatively small particle mass fractions of OxA indicate that standard volume additivity rules for hygroscopicity do not apply. Thus small organic compounds with high O:C are capable of forming low volatility and very low hygroscopicity particles. Given current knowledge of the formation mechanisms of OxA and M-Ox salts, surface enrichment of insoluble M-Ox salts is expected. The resulting formation of an insoluble coating of metal-oxalate salts can explain low particle hygroscopicities. The formation of particles with a hard coating could offer an alternative explanation for observations of glass-like particles with very low viscosity.

[The composition of volatile components of cepe (Boletus edulis) and oyster mushrooms (Pleurotus ostreatus)].

PubMed

Misharina, T A; Mukhutdinova, S M; Zharikova, G G; Terenina, M B; Krikunova, N I

2009-01-01

The composition of aroma compounds in cooked and canned cepe (Boletus edulis) and in cooked oyster mushrooms (Pleurotus ostreatus) is studied using capillary gas chromatography and chromatography-mass spectrometry. It is found that unsaturated alcohols and ketones containing eight atoms of carbon determine the aroma of raw mushrooms and take part in the formation of the aroma of cooked mushrooms as well. The content of these compounds was the highest in canned cepes. In oyster mushrooms, the concentration of these alcohols and ketones was lower in comparison with cepes. The content of aliphatic and aromatic aldehydes was much higher in oyster mushrooms. Volatile aliphatic and heterocyclic Maillard reaction products and isomeric octenols and octenones formed the aroma of cooked and canned mushrooms.

77 FR 52606 - Approval and Promulgation of Air Quality Implementation Plans; Indiana; Volatile Organic...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-30

... Promulgation of Air Quality Implementation Plans; Indiana; Volatile Organic Compounds; Architectural and... sets limits on the amount of volatile organic compounds (VOC) in architectural and industrial... Indiana SIP a new rule within Title 326, Article 8 ``Volatile Organic Compound Rules'' that limits the VOC...

Formation of highly oxygenated organic molecules from aromatic compounds

NASA Astrophysics Data System (ADS)

Molteni, Ugo; Bianchi, Federico; Klein, Felix; El Haddad, Imad; Frege, Carla; Rossi, Michel J.; Dommen, Josef; Baltensperger, Urs

2018-02-01

Anthropogenic volatile organic compounds (AVOCs) often dominate the urban atmosphere and consist to a large degree of aromatic hydrocarbons (ArHCs), such as benzene, toluene, xylenes, and trimethylbenzenes, e.g., from the handling and combustion of fuels. These compounds are important precursors for the formation of secondary organic aerosol. Here we show that the oxidation of aromatics with OH leads to a subsequent autoxidation chain reaction forming highly oxygenated molecules (HOMs) with an O : C ratio of up to 1.09. This is exemplified for five single-ring ArHCs (benzene, toluene, o-/m-/p-xylene, mesitylene (1,3,5-trimethylbenzene) and ethylbenzene), as well as two conjugated polycyclic ArHCs (naphthalene and biphenyl). We report the elemental composition of the HOMs and show the differences in the oxidation patterns of these ArHCs. A potential pathway for the formation of these HOMs from aromatics is presented and discussed. We hypothesize that AVOCs may contribute substantially to new particle formation events that have been detected in urban areas.

Effect of a triclosan/PVM/MA copolymer/fluoride dentifrice on volatile sulfur compounds in vitro.

PubMed

Pilch, S; Williams, M I; Cummins, D

2005-01-01

The objective of the investigation was to document the in vitro efficacy of a triclosan/PVM/MA copolymer/fluoride (TCF) dentifrice against the formation of volatile sulfur compounds (VSC) as well as the growth of H2S-producing bacteria. Clinical studies using organoleptic judges, gas chromatography, or a portable sulfide monitor have generally been employed in the assessment of treatments for the control of oral malodor. However, these studies are not appropriate for screening purposes because of the expense and time required. An in vitro method was developed for the purpose of screening new compounds, agents or formulations for their ability to control VSC formation and for determining bio-equivalence of efficacy when implementing changes in existing formulations. The method combines basic microbiological methods, dynamic flow cell techniques and head space analysis. The in vitro VSC method was validated by comparing the efficacy of two dentifrices containing TCF with a control fluoride dentifrice as the TCF products have been clinically proven to control oral malodor. In the validation studies, the TCF-containing dentifrices were significantly better (P < 0.05) than the control dentifrice in inhibiting VSC formation and reducing H(2)S-producing bacteria. For example, when compared with baseline, the TCF dentifrices reduced VSC formation between 42 and 49% compared with the control dentifrice which reduced VSC formation 3%. There was no significant difference (P > 0.05) between the two TCF dentifrice formulations. Using an in vitro breath VSC model, it has been demonstrated that two variants of a dentifrice containing triclosan, PVM/MA copolymer and fluoride have efficacy that is significantly better than a control fluoridated dentifrice and that there is no significant difference between the triclosan/PVM/MA copolymer/fluoride dentifrice variants.

Determination of volatile organic compound emissions and ozone formation from spraying solvent-based pesticides.

PubMed

Kumar, Anuj; Howard, Cody J; Derrick, Doniche; Malkina, Irina L; Mitloehner, Frank M; Kleeman, Michael J; Alaimo, Christopher P; Flocchini, Robert G; Green, Peter G

2011-01-01

Large-scale agricultural activities have come under scrutiny for possible contributions to the emission of ozone precursors. The San Joaquin Valley (SJV) of California is an area with intense agricultural activity that exceeds the federal ozone standards for more than 30 to 40 d yr(-1) and the more stringent state standards for more than 100 d yr(-1). Pesticides are used widely in both agricultural and residential subregions of the SJV, but the largest use, by weight of "active ingredient," is in agriculture. The objective of the study was to determine the role of pesticide application on airborne volatile organic compounds (VOC) concentrations and ozone formation in the SJV. The ozone formation from the pesticide formulation sprayed on commercial orchards was studied using two transportable smog chambers at four application sites during the summers of 2007 and 2008. In addition to the direct measurements of ozone formation, airborne VOC concentrations were measured before and after pesticide spraying using canister and sorbent tube sampling techniques. Soil VOC concentrations were also measured to understand the distribution of VOCs between different environmental compartments. Numerous VOCs were detected in the air and soil samples throughout the experiment but higher molecular weight aromatic hydrocarbons were the primary compounds observed in elevated concentrations immediately after pesticide spraying. Measurements indicate that the ozone concentration formed by VOC downwind of the orchard may increase up to 15 ppb after pesticide application, with a return back to prespray levels after 1 to 2 d. by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Increase in volatilization of organic compounds using air sparging through addition in alcohol in a soil-water system.

PubMed

Chao, Huan-Ping; Hsieh, Lin-Han Chiang; Tran, Hai Nguyen

2018-02-15

This study developed a novel method to promote the remediation efficiency of air sparging. According to the enhanced-volatilization theory presented in this study, selected alcohols added to groundwater can highly enhance the volatilization amounts of organic compounds with high Henry's law constants. In this study, the target organic compounds consisted of n-hexane, n-heptane, benzene, toluene, 1,1,2-trichloroethane, and tetrachloroethene. n-pentanol, n-hexanol, and n-heptanol were used to examine the changes in the volatilization amounts of organic compounds in the given period. Two types of soils with high and low organic matter were applied to evaluate the transport of organic compounds in the soil-water system. The volatilization amounts of the organic compounds increased with increasing alcohol concentrations. The volatilization amounts of the test organic compounds exhibited a decreasing order: n-heptanol>n-hexanol>n-pentanol. When 10mg/L n-heptanol was added to the system, the maximum volatilization enhancement rate was 18-fold higher than that in distilled water. Samples of soil with high organic matter might reduce the volatilization amounts by a factor of 5-10. In the present study, the optimal removal efficiency for aromatic compounds was approximately 98%. Copyright © 2017 Elsevier B.V. All rights reserved.

Simultaneous control of apparent extract and volatile compounds concentrations in low-malt beer fermentation.

PubMed

Kobayashi, Michiko; Nagahisa, Keisuke; Shimizu, Hiroshi; Shioya, Suteaki

2006-12-01

Volatile compounds cause undesirable flavor when their concentrations exceed threshold values in beer fermentation. The objective of this study is to develop a system for controlling apparent extract concentration, which indicates the fermentation degree and which should be decreased below a targeted value at a fixed time under a constraint of tolerable amounts of volatile compounds. In beer fermentation, even though the production of volatile compounds is suppressed by maintaining a low fermentation temperature, a low temperature causes a delay in the control of apparent extract concentration. Volatile compound concentration was estimated on-line, and the simulation of apparent extract consumption and volatile compound production was performed. To formulate various beer tastes and conserve energy for attemperation, optimal temperature profiles were determined using a genetic algorithm (GA). The developed feedback control of the brewing temperature profile was successfully applied, and apparent extract and volatile compound concentrations at a fixed time reached their target concentrations. Additionally, the control technique developed in this study enables us to brew a wide variety of beers with different tastes.

Influence of physicochemical characteristics and high pressure processing on the volatile fraction of Iberian dry-cured ham.

PubMed

Martínez-Onandi, Nerea; Rivas-Cañedo, Ana; Ávila, Marta; Garde, Sonia; Nuñez, Manuel; Picon, Antonia

2017-09-01

The volatile fraction of 30 Iberian dry-cured hams of different physicochemical characteristics and the effect of high pressure processing (HPP) at 600MPa on volatile compounds were investigated. According to the analysis of variance carried out on the levels of 122 volatile compounds, intramuscular fat content influenced the levels of 8 benzene compounds, 5 carboxylic acids, 2 ketones, 2 furanones, 1 alcohol, 1 aldehyde and 1 sulfur compound, salt concentration influenced the levels of 1 aldehyde and 1 ketone, salt-in-lean ratio had no effect on volatile compounds, and water activity influenced the levels of 3 sulfur compounds, 1 alcohol and 1 aldehyde. HPP-treated samples of Iberian ham had higher levels of 4 compounds and lower levels of 31 compounds than untreated samples. A higher influence of HPP treatment on volatile compounds than physicochemical characteristics was observed for Iberian ham. Therefore, HPP treatment conditions should be optimized in order to diminish its possible effect on Iberian ham odor and aroma characteristics. Copyright © 2017 Elsevier Ltd. All rights reserved.

Volatile profiling reveals intracellular metabolic changes in Aspergillus parasiticus: veA regulates branched chain amino acid and ethanol metabolism

PubMed Central

2010-01-01

Background Filamentous fungi in the genus Aspergillus produce a variety of natural products, including aflatoxin, the most potent naturally occurring carcinogen known. Aflatoxin biosynthesis, one of the most highly characterized secondary metabolic pathways, offers a model system to study secondary metabolism in eukaryotes. To control or customize biosynthesis of natural products we must understand how secondary metabolism integrates into the overall cellular metabolic network. By applying a metabolomics approach we analyzed volatile compounds synthesized by Aspergillus parasiticus in an attempt to define the association of secondary metabolism with other metabolic and cellular processes. Results Volatile compounds were examined using solid phase microextraction - gas chromatography/mass spectrometry. In the wild type strain Aspergillus parasiticus SU-1, the largest group of volatiles included compounds derived from catabolism of branched chain amino acids (leucine, isoleucine, and valine); we also identified alcohols, esters, aldehydes, and lipid-derived volatiles. The number and quantity of the volatiles produced depended on media composition, time of incubation, and light-dark status. A block in aflatoxin biosynthesis or disruption of the global regulator veA affected the volatile profile. In addition to its multiple functions in secondary metabolism and development, VeA negatively regulated catabolism of branched chain amino acids and synthesis of ethanol at the transcriptional level thus playing a role in controlling carbon flow within the cell. Finally, we demonstrated that volatiles generated by a veA disruption mutant are part of the complex regulatory machinery that mediates the effects of VeA on asexual conidiation and sclerotia formation. Conclusions 1) Volatile profiling provides a rapid, effective, and powerful approach to identify changes in intracellular metabolic networks in filamentous fungi. 2) VeA coordinates the biosynthesis of secondary metabolites with catabolism of branched chain amino acids, alcohol biosynthesis, and β-oxidation of fatty acids. 3) Intracellular chemical development in A. parasiticus is linked to morphological development. 4) Understanding carbon flow through secondary metabolic pathways and catabolism of branched chain amino acids is essential for controlling and customizing production of natural products. PMID:20735852

Considering the future of anthropogenic gas-phase organic compound emissions and the increasing influence of non-combustion sources on urban air quality

NASA Astrophysics Data System (ADS)

Khare, Peeyush; Gentner, Drew R.

2018-04-01

Decades of policy in developed regions has successfully reduced total anthropogenic emissions of gas-phase organic compounds, especially volatile organic compounds (VOCs), with an intentional, sustained focus on motor vehicles and other combustion-related sources. We examine potential secondary organic aerosol (SOA) and ozone formation in our case study megacity (Los Angeles) and demonstrate that non-combustion-related sources now contribute a major fraction of SOA and ozone precursors. Thus, they warrant greater attention beyond indoor environments to resolve large uncertainties in their emissions, oxidation chemistry, and outdoor air quality impacts in cities worldwide. We constrain the magnitude and chemical composition of emissions via several bottom-up approaches using chemical analyses of products, emissions inventory assessments, theoretical calculations of emission timescales, and a survey of consumer product material safety datasheets. We demonstrate that the chemical composition of emissions from consumer products as well as commercial and industrial products, processes, and materials is diverse across and within source subcategories. This leads to wide ranges of SOA and ozone formation potentials that rival other prominent sources, such as motor vehicles. With emission timescales from minutes to years, emission rates and source profiles need to be included, updated, and/or validated in emissions inventories with expected regional and national variability. In particular, intermediate-volatility and semi-volatile organic compounds (IVOCs and SVOCs) are key precursors to SOA, but are excluded or poorly represented in emissions inventories and exempt from emissions targets. We present an expanded framework for classifying VOC, IVOC, and SVOC emissions from this diverse array of sources that emphasizes a life cycle approach over longer timescales and three emission pathways that extend beyond the short-term evaporation of VOCs: (1) solvent evaporation, (2) solute off-gassing, and (3) volatilization of degradation by-products. Furthermore, we find that ambient SOA formed from these non-combustion-related emissions could be misattributed to fossil fuel combustion due to the isotopic signature of their petroleum-based feedstocks.

78 FR 11618 - Approval and Promulgation of Implementation Plans Tennessee: Revisions to Volatile Organic...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-19

... Promulgation of Implementation Plans Tennessee: Revisions to Volatile Organic Compound Definition AGENCY..., SIP revision adds 17 compounds to the list of compounds excluded from the definition of ``Volatile Organic Compound''. EPA is approving this SIP revision because the State has demonstrated that it is...

Synergetic Use of Principal Component Analysis Applied to Normed Physicochemical Measurements and GC × GC-MS to Reveal the Stabilization Effect of Selected Essential Oils on Heated Rapeseed Oil.

PubMed

Sghaier, Lilia; Cordella, Christophe B Y; Rutledge, Douglas N; Lefèvre, Fanny; Watiez, Mickaël; Breton, Sylvie; Sassiat, Patrick; Thiebaut, Didier; Vial, Jérôme

2017-06-01

Lipid oxidation leads to the formation of volatile compounds and very often to off-flavors. In the case of the heating of rapeseed oil, unpleasant odors, characterized as a fishy odor, are emitted. In this study, 2 different essential oils (coriander and nutmeg essential oils) were added to refined rapeseed oil as odor masking agents. The aim of this work was to determine a potential antioxidant effect of these essential oils on the thermal stability of rapeseed oil subject to heating cycles between room temperature and 180 °C. For this purpose, normed determinations of different parameters (peroxide value, anisidine value, and the content of total polar compounds, free fatty acids and tocopherols) were carried out to examine the differences between pure and degraded oil. No significant difference was observed between pure rapeseed oil and rapeseed oil with essential oils for each parameter separately. However, a stabilizing effect of the essential oils, with a higher effect for the nutmeg essential oil was highlighted by principal component analysis applied on physicochemical dataset. Moreover, the analysis of the volatile compounds performed by GC × GC showed a substantial loss of the volatile compounds of the essential oils from the first heating cycle. © 2017 Institute of Food Technologists®.

A mass transfer model of ethanol emission from thin layers of corn silage

USDA-ARS?s Scientific Manuscript database

Dairies may be important emission sources for volatile organic compounds (VOCs). Reactive organic gases (ROG) emissions from dairy farms are the second largest source responsible for ozone formation in the California’s San Joaquin Valley. Animal feed was found to be a major ROG emission source on da...

Comprehensive characterization of atmospheric organic carbon at a forested site

NASA Astrophysics Data System (ADS)

Hunter, James F.; Day, Douglas A.; Palm, Brett B.; Yatavelli, Reddy L. N.; Chan, Arthur W. H.; Kaser, Lisa; Cappellin, Luca; Hayes, Patrick L.; Cross, Eben S.; Carrasquillo, Anthony J.; Campuzano-Jost, Pedro; Stark, Harald; Zhao, Yunliang; Hohaus, Thorsten; Smith, James N.; Hansel, Armin; Karl, Thomas; Goldstein, Allen H.; Guenther, Alex; Worsnop, Douglas R.; Thornton, Joel A.; Heald, Colette L.; Jimenez, Jose L.; Kroll, Jesse H.

2017-10-01

Atmospheric organic compounds are central to key chemical processes that influence air quality, ecological health, and climate. However, longstanding difficulties in predicting important quantities such as organic aerosol formation and oxidant lifetimes indicate that our understanding of atmospheric organic chemistry is fundamentally incomplete, probably due in part to the presence of organic species that are unmeasured using standard analytical techniques. Here we present measurements of a wide range of atmospheric organic compounds--including previously unmeasured species--taken concurrently at a single site (a ponderosa pine forest during summertime) by five state-of-the-art mass spectrometric instruments. The combined data set provides a comprehensive characterization of atmospheric organic carbon, covering a wide range in chemical properties (volatility, oxidation state, and molecular size), and exhibiting no obvious measurement gaps. This enables the first construction of a measurement-based local organic budget, highlighting the high emission, deposition, and oxidation fluxes in this environment. Moreover, previously unmeasured species, including semivolatile and intermediate-volatility organic species (S/IVOCs), account for one-third of the total organic carbon, and (within error) provide closure on both OH reactivity and potential secondary organic aerosol formation.

Volatile composition of some Brazilian fruits: umbu-caja (Spondias citherea), camu-camu (Myrciaria dubia), Araça-boi (Eugenia stipitata), and Cupuaçu (Theobroma grandiflorum).

PubMed

Franco, M R; Shibamoto, T

2000-04-01

Twenty-one volatile compounds were identified for the first time by GC-MS in umbu-caja and in camu-camu, plus 30 volatile compounds were identified in araça-boi samples. Terpenic compounds predominated among the volatile compounds in these fruit samples, with the major compounds being identified as cis-beta-ocimene and caryophyllene in the northeastern fruit; alpha-pinene and d-limonene were the most abundant volatile compounds in the headspace of the Amazonian fruit camu-camu. Sesquiterpenes were the most abundant compounds in the araça-boi sample, with germacrene D presenting a higher relative percentage. The chemical class of esters predominated in the cupuaçu sample. Ethyl butyrate and hexanoate were the major compounds in the headspace of this Amazonian fruit.

Limited effect of anthropogenic nitrogen oxides on Secondary Organic Aerosol formation

DOE PAGES

Zheng, Y.; Unger, N.; Hodzic, A.; ...

2015-08-28

Globally, secondary organic aerosol (SOA) is mostly formed from emissions of biogenic volatile organic compounds (VOCs) by vegetation, but can be modified by human activities as demonstrated in recent research. Specifically, nitrogen oxides (NO x = NO + NO 2) have been shown to play a critical role in the chemical formation of low volatility compounds. We have updated the SOA scheme in the global NCAR Community Atmospheric Model version 4 with chemistry (CAM4-chem) by implementing a 4-product Volatility Basis Set (VBS) scheme, including NO x-dependent SOA yields and aging parameterizations. The predicted organic aerosol amounts capture both the magnitudemore » and distribution of US surface annual mean measurements from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network by 50 %, and the simulated vertical profiles are within a factor of two compared to Aerosol Mass Spectrometer (AMS) measurements from 13 aircraft-based field campaigns across different region and seasons. We then perform sensitivity experiments to examine how the SOA loading responds to a 50 % reduction in anthropogenic nitric oxide (NO) emissions in different regions. We find limited SOA reductions of 0.9 to 5.6, 6.4 to 12.0 and 0.9 to 2.8 % for global, the southeast US and the Amazon NO x perturbations, respectively. The fact that SOA formation is almost unaffected by changes in NO x can be largely attributed to buffering in chemical pathways (low- and high-NO x pathways, O 3 versus NO 3-initiated oxidation) and to offsetting tendencies in the biogenic versus anthropogenic SOA responses.« less

"More than Honey": Investigation on Volatiles from Monovarietal Honeys Using New Analytical and Sensory Approaches.

PubMed

Siegmund, Barbara; Urdl, Katharina; Jurek, Andrea; Leitner, Erich

2018-03-14

Eight monovarietal honeys from dandelion, fir tree, linden tree, chestnut tree, robinia, orange, lavender, and rape were investigated with respect to their volatile compounds and sensory properties. Analysis of the volatile compounds was performed by gas chromatographic techniques (one-dimensional GC-MS as well as comprehensive GC×GC-MS). For sensory evaluation Napping in combination with ultraflash profiling was applied using sensory experts. For dandelion honey, 34 volatile compounds are described for the first time to be present in dandelion honey. PCA and cluster analysis of the volatile compounds, respectively, show high correlation with the PCA obtained from sensory evaluation. Lavender and linden honey showed sensory characteristics that were not expected from these honey types. Analysis of the volatile compounds resulted in the identification of odor-active compounds that are very likely derived from sources other than the respective honeyflow. Contamination with essential oils used in apiculture is very likely to be the reason for the occurrence of these compounds in the investigated honeys.

Volatile trace compounds released from municipal solid waste at the transfer stage: Evaluation of environmental impacts and odour pollution.

PubMed

Zhao, Yan; Lu, Wenjing; Wang, Hongtao

2015-12-30

Odour pollution caused by municipal solid waste is a public concern. This study quantitatively evaluated the concentration, environmental impacts, and olfaction of volatile trace compounds released from a waste transfer station. Seventy-six compounds were detected, and ethanol presented the highest releasing rate and ratio of 14.76 kg/d and 12.30 g/t of waste, respectively. Life cycle assessment showed that trichlorofluoromethane and dichlorodifluoromethane accounted for more than 99% of impact potentials to global warming and approximately 70% to human toxicity (non-carcinogenic). The major contributor for both photochemical ozone formation and ecotoxicity was ethanol. A detection threshold method was also used to evaluate odour pollution. Five compounds including methane thiol, hydrogen sulphide, ethanol, dimethyl disulphide, and dimethyl sulphide, with dilution multiples above one, were considered the critical compounds. Methane thiol showed the highest contribution to odour pollution of more than 90%, as indicated by its low threshold. Comparison of the contributions of the compounds to different environmental aspects indicated that typical pollutants varied based on specific evaluation targets and therefore should be comprehensively considered. This study provides important information and scientific methodology to elucidate the impacts of odourant compounds to the environment and odour pollution. Copyright © 2015 Elsevier B.V. All rights reserved.

Organic Chemical Characterization and Mass Balance of a Hydraulically Fractured Well: From Fracturing Fluid to Produced Water over 405 Days.

PubMed

Rosenblum, James; Thurman, E Michael; Ferrer, Imma; Aiken, George; Linden, Karl G

2017-12-05

A long-term field study (405 days) of a hydraulically fractured well from the Niobrara Formation in the Denver-Julesburg Basin was completed. Characterization of organic chemicals used in hydraulic fracturing and their changes through time, from the preinjected fracturing fluid to the produced water, was conducted. The characterization consisted of a mass balance by dissolved organic carbon (DOC), volatile organic analysis by gas chromatography/mass spectrometry, and nonvolatile organic analysis by liquid chromatography/mass spectrometry. DOC decreased from 1500 mg/L in initial flowback to 200 mg/L in the final produced water. Only ∼11% of the injected DOC returned by the end of the study, with this 11% representing a maximum fraction returned since the formation itself contributes DOC. Furthermore, the majority of returning DOC was of the hydrophilic fraction (60-85%). Volatile organic compound analysis revealed substantial concentrations of individual BTEX compounds (0.1-11 mg/L) over the 405-day study. Nonvolatile organic compounds identified were polyethylene glycols (PEGs), polypropylene glycols (PPG), linear alkyl-ethoxylates, and triisopropanolamine (TIPA). The distribution of PEGs, PPGs, and TIPA and their ubiquitous presence in our samples and the literature illustrate their potential as organic tracers for treatment operations or in the event of an environmental spill.

Production, Characterization, and Stability of Orange or Eucalyptus Essential Oil/β-Cyclodextrin Inclusion Complex.

PubMed

Kringel, Dianini Hüttner; Antunes, Mariana Dias; Klein, Bruna; Crizel, Rosane Lopes; Wagner, Roger; de Oliveira, Roberto Pedroso; Dias, Alvaro Renato Guerra; Zavareze, Elessandra da Rosa

2017-11-01

The aim of this study was to produce and characterize inclusion complexes (IC) between β-cyclodextrin (β-CD) and orange essential oil (OEO) or eucalyptus essential oil (EEO), and to compare these with their pure compounds and physical mixtures. The samples were evaluated by chemical composition, morphology, thermal stability, and volatile compounds by static headspace-gas chromatography (SH-GC). Comparing the free essential oil and physical mixture with the inclusion complex, of both essential oils (OEO and EEO), it was observed differences occurred in the chemical composition, thermal stability, and morphology. These differences show that there was the formation of the inclusion complex and demonstrate the necessity of the precipitation method used to guarantee the interaction between β-CD and essential oils. The slow loss of the volatile compounds from both essential oils, when complexed with β-CD, showed a higher stability when compared with their physical mixtures and free essential oils. Therefore, the results showed that the chemical composition, molecular size, and structure of the essential oils influence the characteristics of the inclusion complexes. The application of the β-CD in the formation of inclusion complexes with essential oils can expand the potential applications in foods. © 2017 Institute of Food Technologists®.

Organic chemical characterization and mass balance of a hydraulically fractured well: From fracturing fluid to produced water over 405 days

USGS Publications Warehouse

Rosenblum, James; Thurman, E. Michael; Ferrer, Imma; Aiken, George R.; Linden, Karl G.

2017-01-01

A long-term field study (405 days) of a hydraulically fractured well from the Niobrara Formation in the Denver-Julesburg Basin was completed. Characterization of organic chemicals used in hydraulic fracturing and their changes through time, from the preinjected fracturing fluid to the produced water, was conducted. The characterization consisted of a mass balance by dissolved organic carbon (DOC), volatile organic analysis by gas chromatography/mass spectrometry, and nonvolatile organic analysis by liquid chromatography/mass spectrometry. DOC decreased from 1500 mg/L in initial flowback to 200 mg/L in the final produced water. Only ∼11% of the injected DOC returned by the end of the study, with this 11% representing a maximum fraction returned since the formation itself contributes DOC. Furthermore, the majority of returning DOC was of the hydrophilic fraction (60–85%). Volatile organic compound analysis revealed substantial concentrations of individual BTEX compounds (0.1–11 mg/L) over the 405-day study. Nonvolatile organic compounds identified were polyethylene glycols (PEGs), polypropylene glycols (PPG), linear alkyl-ethoxylates, and triisopropanolamine (TIPA). The distribution of PEGs, PPGs, and TIPA and their ubiquitous presence in our samples and the literature illustrate their potential as organic tracers for treatment operations or in the event of an environmental spill.

Global-scale combustion sources of organic aerosols: sensitivity to formation and removal mechanisms

NASA Astrophysics Data System (ADS)

Tsimpidi, Alexandra P.; Karydis, Vlassis A.; Pandis, Spyros N.; Lelieveld, Jos

2017-06-01

Organic compounds from combustion sources such as biomass burning and fossil fuel use are major contributors to the global atmospheric load of aerosols. We analyzed the sensitivity of model-predicted global-scale organic aerosols (OA) to parameters that control primary emissions, photochemical aging, and the scavenging efficiency of organic vapors. We used a computationally efficient module for the description of OA composition and evolution in the atmosphere (ORACLE) of the global chemistry-climate model EMAC (ECHAM/MESSy Atmospheric Chemistry). A global dataset of aerosol mass spectrometer (AMS) measurements was used to evaluate simulated primary (POA) and secondary (SOA) OA concentrations. Model results are sensitive to the emission rates of intermediate-volatility organic compounds (IVOCs) and POA. Assuming enhanced reactivity of semi-volatile organic compounds (SVOCs) and IVOCs with OH substantially improved the model performance for SOA. The use of a hybrid approach for the parameterization of the aging of IVOCs had a small effect on predicted SOA levels. The model performance improved by assuming that freshly emitted organic compounds are relatively hydrophobic and become increasingly hygroscopic due to oxidation.

Volatilization and Precipitation of Tellurium by Aerobic, Tellurite-Resistant Marine Microbes▿ †

PubMed Central

Ollivier, Patrick R. L.; Bahrou, Andrew S.; Marcus, Sarah; Cox, Talisha; Church, Thomas M.; Hanson, Thomas E.

2008-01-01

Microbial resistance to tellurite, an oxyanion of tellurium, is widespread in the biosphere, but the geochemical significance of this trait is poorly understood. As some tellurite resistance markers appear to mediate the formation of volatile tellurides, the potential contribution of tellurite-resistant microbial strains to trace element volatilization in salt marsh sediments was evaluated. Microbial strains were isolated aerobically on the basis of tellurite resistance and subsequently examined for their capacity to volatilize tellurium in pure cultures. The tellurite-resistant strains recovered were either yeasts related to marine isolates of Rhodotorula spp. or gram-positive bacteria related to marine strains within the family Bacillaceae based on rRNA gene sequence comparisons. Most strains produced volatile tellurides, primarily dimethyltelluride, though there was a wide range of the types and amounts of species produced. For example, the Rhodotorula spp. produced the greatest quantities and highest diversity of volatile tellurium compounds. All strains also produced methylated sulfur compounds, primarily dimethyldisulfide. Intracellular tellurium precipitates were a major product of tellurite metabolism in all strains tested, with nearly complete recovery of the tellurite initially provided to cultures as a precipitate. Different strains appeared to produce different shapes and sizes of tellurium containing nanostructures. These studies suggest that aerobic marine yeast and Bacillus spp. may play a greater role in trace element biogeochemistry than has been previously assumed, though additional work is needed to further define and quantify their specific contributions. PMID:18849455

Org Areo Boreal Forest Sources, compositions and properties of newly formed and regional organic aerosol in a boreal forest during the Biogenic Aerosol: Effects on Clouds and Climate Campaign

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thornton, Joel A

The major goals of this project were to make unique measurements, as part of the DOE sponsored Biogenic Aerosol Effects on Clouds and Climate (BAECC) campaign, of the volatility and molecular composition of organic aerosol, as well as gas-phase concentrations of oxygenated organic compounds that interact and affect organic aerosol. In addition, we aimed to conduct a similar set of measurements as part of a collaborative set of environmental simulation chamber experiments at PNNL, the aim of which was to simulate the atmospheric oxidation of key biogenic volatile organic compounds (BVOC) and study the associated formation and evolution of secondarymore » organic aerosol (SOA). The target BVOC were a set of monoterpenes, isoprene, and related intermediates such as IEPOX. The ultimate goal of such measurements are to develop a more detailed mechanistic understanding of the sensitivity of SOA mass formation and lifetime to precursor and environmental conditions. Molecular composition and direct volatility measurements provide robust tracers of chemical processing and properties. As such, meeting these goals will allow for stronger constraints on the types of processes and their fundamental descriptions needed to simulate aerosol particle number and size, and cloud nucleating ability in regional and global earth system models.« less

Content and Formation Cause of VOCs in Medical Waste Non-incineration Treatment Project

NASA Astrophysics Data System (ADS)

Dengchao, Jin; Hongjun, Teng; Zhenbo, Bao; Yang, Li

2018-02-01

When medical waste is treated by non-incineration technology, volatile organic compounds in the waste will be volatile out and form odor pollution. This paper studied VOCs productions in medical waste steam treatment project, microwave treatment project and chemical dinifection project. Sampling and analysis were carried out on the waste gas from treatment equipment and the gas in treatment workshop. The contents of nine VOCs were determined. It was found that the VOCs content in the exhaust gas at the outlet of steam treatment unit was much higher than that of microwave and chemical treatment unit, while the content of VOCs in the chemical treatment workshop was higher than that in the steam and microwave treatment workshop. The formation causes of VOCs were also analyzed and discussed in this paper.

Speciated Chemical Composition of Biomass Burning Aerosol from Various Fuels during FIREX

NASA Astrophysics Data System (ADS)

Jen, C.; Hatch, L. E.; Kreisberg, N. M.; Selimovic, V.; Yokelson, R. J.; Barsanti, K.; Goldstein, A. H.

2017-12-01

Biomass burning is the largest global source of atmospheric primary carbonaceous aerosols and the second largest global source of non-methane organic compounds, including volatile and semi-volatile organic compounds that are now understood to be major contributors to secondary particle formation in the atmosphere. As wildfires in forested regions such as the western United States become larger and more frequent, understanding the chemical composition of biomass burning organic aerosol is needed to better predict their increasing impact on human health, air quality, and climate. This study presents emission profiles of chemically speciated intermediate and semi-volatile organic compounds present in biomass burning aerosol particles ≤1.0 μm. Biomass burning organic aerosol (BBOA) samples from a variety of fuel types and burning conditions were collected during the FIREX campaign at the USDA Fire Lab (Missoula, MT). Fuels were primarily selected from vegetation commonly found in the western United States, such as ponderosa pine, lodgepole pine, ceanothus, and chaparral. Collected BBOA was thermally desorbed from the filters and analyzed using online derivatization and 2-dimensional gas chromatography with an electron impact (70 eV) and vacuum ultra violet light (10.5 eV) high resolution time of flight mass spectrometer for compound identification. Emission profiles for specific compounds (e.g., levoglucosan) and families of compounds (e.g., sugars and methoxyphenols) show distinct variations between different fuel types, with major differences between fresh and partially decomposed fuels. Results also illustrate the variability in chemical species between burns conducted under similar conditions. Furthermore, chemical fingerprints, representing ratios of normalized emissions for key chemical compounds, were measured for specific fuels/conditions and could be used in future field studies to help identify contributions of various vegetation to total BBOA and in models to estimate the chemical composition of BBOA emissions.

Primary Emission and the Potential of Secondary Aerosol Formation from Chinese Gasoline Engine Exhaust

NASA Astrophysics Data System (ADS)

Hu, Min; Peng, Jianfei; Qin, Yanhong; Du, Zhuofei; Li, Mengjin; Zheng, Rong; Zheng, Jing; Shang, Dongjie; Lu, Sihua; Wu, Yusheng; Zeng, Limin; Guo, Song; Shao, Min; Wang, Yinhui; Shuai, Shijin

2017-04-01

Along with the urbanization and economic growth, vehicle population in China reached 269 million, ranked the second in the world in 2015. Gasoline vehicle is identified to be the main source for urban PM2.5 in China, accounting for 15%-31%. In this study the impact of fuel components on PM2.5 and volatile organic compounds (VOCs) emissions from a gasoline port fuel injection (PFI) engine and a gasoline direct injection (GDI) engine are discussed. Results show that, higher proportion of aromatics, alkenes or sulfur in gasoline fuel will lead to higher PM emissions. The PM from the PFI engine mainly consists of OC and a small amount of EC and inorganic ions, while the PM discharge from the GDI engine mainly consists of EC, OM and a small amount of inorganic ions. Since the GDI engines can reduce fuel consumption and CO2 emissions, and it would become more and more popular in the near future. The characteristics of POM component, emission factors and source profile were investigated from GDI engine, particularly focused on the effect of engine speed, load and the catalyst, which will be very much helpful for source identification as source indicators. Chamber experiments were conducted to quantify the potential of secondary aerosol formation from exhaust of a PFI gasoline engine and China V gasoline fuel. During 4-5 h simulation, equivalent to10 days of atmospheric photo-oxidation in Beijing, the extreme SOA production was 426 ± 85 mg/kg fuel, with high precursors and OH exposure. 14% of SOA measured in the chamber experiments could be explained through the oxidation of speciated single-ring aromatics. Unspeciated precursors, such as intermediate-volatility organic compounds and semi-volatility organic compounds, might be significant for SOA formation from gasoline VOCs. We concluded that reduction of emissions of aerosol precursor gases from vehicles is essential to mediate pollution in China.

Chemical characterization of SOA formed from aqueous-phase reactions of phenols with the triplet excited state of carbonyl and hydroxyl radical

DOE PAGES

Yu, L.; Smith, J.; Laskin, A.; ...

2014-12-23

Phenolic compounds, which are emitted in significant amounts from biomass burning, can undergo fast reactions in atmospheric aqueous phases to form secondary organic aerosol (aqSOA). In this study, we investigate the reactions of phenol (compound with formula C 6H 5OH)), guaiacol (2-methoxyphenol), and syringol (2,6-dimethoxyphenol) with two major aqueous-phase oxidants – the triplet excited states of an aromatic carbonyl ( 3C *) and hydroxyl radical (· OH). We thoroughly characterize the low-volatility species produced from these reactions and interpret their formation mechanisms using aerosol mass spectrometry (AMS), nanospray desorption electrospray ionization mass spectrometry (nano-DESI MS), and ion chromatography (IC). Amore » large number of oxygenated molecules are identified, including oligomers containing up to six monomer units, functionalized monomer and oligomers with carbonyl, carboxyl, and hydroxyl groups, and small organic acid anions (e.g., formate, acetate, oxalate, and malate). The average atomic oxygen-to-carbon (O / C) ratios of phenolic aqSOA are in the range of 0.85–1.23, similar to those of low-volatility oxygenated organic aerosol (LV-OOA) observed in ambient air. The aqSOA compositions are overall similar for the same precursor, but the reactions mediated by 3C * are faster than · OH-mediated reactions and produce more oligomers and hydroxylated species at the point when 50% of the phenolic compound has reacted. Profiles determined using a thermodenuder indicate that the volatility of phenolic aqSOA is influenced by both oligomer content and O / C ratio. In addition, the aqSOA shows enhanced light absorption in the UV–visible region, suggesting that aqueous-phase reactions of phenols may contribute to formation of secondary brown carbon in the atmosphere, especially in regions influenced by biomass burning.« less

TEMPORAL VARIABILITY MEASUREMENT OF SPECIFIC VOLATILE ORGANIC COMPOUNDS

EPA Science Inventory

Methodology was developed to determine unambiguously trace levels of volatile organic compounds as they vary in concentration over a variety of time scales. his capability is important because volatile organic compounds (VOCs) are usually measure by time-integrative techniques th...

Advances in fruit aroma volatile research.

PubMed

El Hadi, Muna Ahmed Mohamed; Zhang, Feng-Jie; Wu, Fei-Fei; Zhou, Chun-Hua; Tao, Jun

2013-07-11

Fruits produce a range of volatile compounds that make up their characteristic aromas and contribute to their flavor. Fruit volatile compounds are mainly comprised of esters, alcohols, aldehydes, ketones, lactones, terpenoids and apocarotenoids. Many factors affect volatile composition, including the genetic makeup, degree of maturity, environmental conditions, postharvest handling and storage. There are several pathways involved in volatile biosynthesis starting from lipids, amino acids, terpenoids and carotenoids. Once the basic skeletons are produced via these pathways, the diversity of volatiles is achieved via additional modification reactions such as acylation, methylation, oxidation/reduction and cyclic ring closure. In this paper, we review the composition of fruit aroma, the characteristic aroma compounds of several representative fruits, the factors affecting aroma volatile, and the biosynthetic pathways of volatile aroma compounds. We anticipate that this review would provide some critical information for profound research on fruit aroma components and their manipulation during development and storage.

Multiple new-particle growth pathways observed at the US DOE Southern Great Plains field site

DOE PAGES

Hodshire, Anna L.; Lawler, Michael J.; Zhao, Jun; ...

2016-07-28

New-particle formation (NPF) is a significant source of aerosol particles into the atmosphere. However, these particles are initially too small to have climatic importance and must grow, primarily through net uptake of low-volatility species, from diameters  ∼  1 to 30–100 nm in order to potentially impact climate. There are currently uncertainties in the physical and chemical processes associated with the growth of these freshly formed particles that lead to uncertainties in aerosol-climate modeling. Four main pathways for new-particle growth have been identified: condensation of sulfuric-acid vapor (and associated bases when available), condensation of organic vapors, uptake of organic acids through acid–base chemistrymore » in the particle phase, and accretion of organic molecules in the particle phase to create a lower-volatility compound that then contributes to the aerosol mass. The relative importance of each pathway is uncertain and is the focus of this work. The 2013 New Particle Formation Study (NPFS) measurement campaign took place at the DOE Southern Great Plains (SGP) facility in Lamont, Oklahoma, during spring 2013. Measured gas- and particle-phase compositions during these new-particle growth events suggest three distinct growth pathways: (1) growth by primarily organics, (2) growth by primarily sulfuric acid and ammonia, and (3) growth by primarily sulfuric acid and associated bases and organics. To supplement the measurements, we used the particle growth model MABNAG (Model for Acid–Base chemistry in NAnoparticle Growth) to gain further insight into the growth processes on these 3 days at SGP. MABNAG simulates growth from (1) sulfuric-acid condensation (and subsequent salt formation with ammonia or amines), (2) near-irreversible condensation from nonreactive extremely low-volatility organic compounds (ELVOCs), and (3) organic-acid condensation and subsequent salt formation with ammonia or amines. MABNAG is able to corroborate the observed differing growth pathways, while also predicting that ELVOCs contribute more to growth than organic salt formation. However, most MABNAG model simulations tend to underpredict the observed growth rates between 10 and 20 nm in diameter; this underprediction may come from neglecting the contributions to growth from semi-to-low-volatility species or accretion reactions. Our results suggest that in addition to sulfuric acid, ELVOCs are also very important for growth in this rural setting. We discuss the limitations of our study that arise from not accounting for semi- and low-volatility organics, as well as nitrogen-containing species beyond ammonia and amines in the model. Quantitatively understanding the overall budget, evolution, and thermodynamic properties of lower-volatility organics in the atmosphere will be essential for improving global aerosol models.« less

Surface microlayer enrichment of volatile organic compounds and semi-volatile organic compounds in drinking water source.

PubMed

Huang, Zhi; Zhou, Wen; Yu, Ya-juan; Zhang, Ai-qian; Han, Shuo-kui; Wang, Lian-sheng

2004-01-01

Enrichment of volatile organic compounds(VOC) and semi-volatility organic compounds(SVOC) in surface microlayer(SM) of three drinking water sources were studied. The enrichment factor(EFs) were 0.67 to 13.37 and 0.16 to 136, respectively. The results showed some VOC and most SVOC could enrich in SM. Some EFs of SVOC was quite high. Suspension and temperature could affect EFs of SVOC, slim wind and water movement do not destroy enrichment of organic in SM.

Relationship between the formation of volatile sulfur compounds (VSC) and the severity of the periodontal disease: a pilot study.

PubMed

Nogueira-Filho, G R; Peruzzo, D; Sallum, A W

2008-03-01

This aim of this study was to evaluate the relationship between the formation of volatile sulfur compounds (VSC) and the severity of different kinds of periodontal disease. Twenty patients suffering from biofilm-related periodontal diseases and a control group of ten healthy individuals were selected. The patients were divided according to their periodontal diagnoses: marginal gingivitis (MG/n = 10) and chronic periodontitis (CP/n = 10). The patients received non-surgical therapy that consisted of motivation, scaling and root planing. Two experimental periods were used: T1 = baseline and T2 = final evaluation after three months. The data analysis showed that CP group had a significant reduction (p < 0.05) in probing depth (PD) and clinical attachment level (CAL), and group MG presented a reduction in GI (p < 0.05). There was a significant reduction (p < 0.05) in the aspartate aminotransferase (AST), N-a-benzoyl-DL-arginine-p-nitroanilide (BAPNA) and VSC levels in both MG and CP groups, although the deeper residual pockets led to higher AST and VSC levels in the CP group. Within the limits of the present pilot study, it can be concluded that the non-surgical therapy may influence VSC formation in a manner dependent on periodontal disease severity.

Insoluble zinc, cupric and tin pyrophosphates inhibit the formation of volatile sulphur compounds.

PubMed

Jonski, G; Young, A; Wåler, S M; Rölla, G

2004-10-01

Oral malodour is mainly a result of the production of volatile sulphur compounds (VSC). The present study was concerned with investigating the anti-VSC effect of insoluble pyrophosphates (PP) of zinc, copper(II) and tin(II). The hypothesis to be tested was that the sulphide anions produced when VSC are solubilized in water have a higher affinity for the respective metal ions than the PP anion. The anti-VSC effects of insoluble PP were compared with the corresponding soluble metal salts using three in vitro methods: saliva putrefaction; dialysis of a suspension of PP and saliva against water; and analysis of water containing hydrogen sulphide and methyl mercaptan gases, and gases in the headspace. The levels of VSC were analysed by gas chromatography in the first and third methods, and released metal ions were analysed by atomic absorption spectroscopy in the second. The results showed that: the insoluble metal PP inhibited VSC formation in saliva by 99-100%; under dialysis, only minute amounts of metal ions are released from the combination of PP and saliva; and the PP lost their metal cations in water containing dissolved gases and inhibited VSC formation. Hence, the results support the experimental hypothesis. Sulphide ions are obviously very strong ligands for these metal ions.

A Preliminary Study of Aroma Composition and Impact Odorants of Cabernet Franc Wines under Different Terrain Conditions of the Loess Plateau Region (China).

PubMed

Jiang, Bao; Zhang, Zhen-Wen

2018-05-05

Due to its appropriate climate characteristics, the Loess Plateau region is considered to be one of the biggest optimal regions for producing high-quality mountain wine in China. However, the complex landform conditions of vineyards are conducive to the formation of mountainous microclimates, which ultimately influence the wine quality. This study aimed to elucidate the influences of three terrain conditions of the Loess Plateau region on the aroma compounds of Cabernet Franc wines by using solid phase microextraction (SPME) with gas chromatography-mass spectrometry (GC-MS). A total of 40, 36 and 35 volatiles were identified and quantified from the flat, lower slope and higher slope vineyards, respectively. Esters were the largest group of volatiles, accounting for 54.6⁻56.6% of total volatiles, followed by alcohols. Wines from the slope lands had the higher levels of aroma compounds than that from flat land. According to their aroma-active values (OAVs), ethyl hexanoate, ethyl octanoate and isoamyl acetate were the most powerful compounds among the eight impact odorants, showing only quantitative but not qualitative differences between the three terrain wines. The shapes of the OAVs for three terrain wines were very similar.

Quadruple sulfur isotope constraints on the origin and cycling of volatile organic sulfur compounds in a stratified sulfidic lake

NASA Astrophysics Data System (ADS)

Oduro, Harry; Kamyshny, Alexey; Zerkle, Aubrey L.; Li, Yue; Farquhar, James

2013-11-01

We have quantified the major forms of volatile organic sulfur compounds (VOSCs) distributed in the water column of stratified freshwater Fayetteville Green Lake (FGL), to evaluate the biogeochemical pathways involved in their production. The lake's anoxic deep waters contain high concentrations of sulfate (12-16 mmol L-1) and sulfide (0.12 μmol L-1 to 1.5 mmol L-1) with relatively low VOSC concentrations, ranging from 0.1 nmol L-1 to 2.8 μmol L-1. Sulfur isotope measurements of combined volatile organic sulfur compounds demonstrate that VOSC species are formed primarily from reduced sulfur (H2S/HS-) and zero-valent sulfur (ZVS), with little input from sulfate. Thedata support a role of a combination of biological and abiotic processes in formation of carbon-sulfur bonds between reactive sulfur species and methyl groups of lignin components. These processes are responsible for very fast turnover of VOSC species, maintaining their low levels in FGL. No dimethylsulfoniopropionate (DMSP) was detected by Electrospray Ionization Mass Spectrometry (ESI-MS) in the lake water column or in planktonic extracts. These observations indicate a pathway distinct from oceanic and coastal marine environments, where dimethylsulfide (DMS) and other VOSC species are principally produced via the breakdown of DMSP by plankton species.

Translational diffusion coefficients of volatile compounds in various aqueous solutions at low and subzero temperatures.

PubMed

Covarrubias-Cervantes, Marco; Champion, Dominique; Debeaufort, Frédéric; Voilley, Andrée

2005-08-24

Translational diffusion coefficients (D(12)) of volatile compounds were measured in model media with the profile concentration method. The influence of sample temperature (from 25 to -10 degrees C) was studied on translational diffusion in sucrose or maltodextrin solutions at various concentrations. Results show that diffusivity of volatile compounds in sucrose solutions is controlled by temperature, molecule size, and the viscosity of the liquid phase as expected with the Stokes-Einstein equation; moreover, physicochemical interactions between volatile compounds and the medium are determinant for diffusion estimation. At negative temperature, the winding path induced by an ice crystal content of >70% lowered volatile compound diffusion. On the contrary, no influence on translational diffusion coefficients was observed for lower ice content.

Particle growth kinetics over the Amazon rainforest

NASA Astrophysics Data System (ADS)

Pinterich, T.; Andreae, M. O.; Artaxo, P.; Kuang, C.; Longo, K.; Machado, L.; Manzi, A. O.; Martin, S. T.; Mei, F.; Pöhlker, C.; Pöhlker, M. L.; Poeschl, U.; Shilling, J. E.; Shiraiwa, M.; Tomlinson, J. M.; Zaveri, R. A.; Wang, J.

2016-12-01

Aerosol particles larger than 100 nm play a key role in global climate by acting as cloud condensation nuclei (CCN). Most of these particles, originated from new particle formation or directly emitted into the atmospheric, are initially too small to serve as CCN. These small particles grow to CCN size mainly through condensation of secondary species. In one extreme, the growth is dictated by kinetic condensation of very low-volatility compounds, favoring the growth of the smallest particles; in the other extreme, the process is driven by Raoult's law-based equilibrium partitioning of semi-volatile organic compound, favoring the growth of larger particles. These two mechanisms can lead to very different production rates of CCN. The growth of particles depends on a number of parameters, including the volatility of condensing species, particle phase, and diffusivity inside the particles, and this process is not well understood in part due to lack of ambient data. Here we examine atmospheric particle growth using high-resolution size distributions measured onboard the DOE G-1 aircraft during GoAmazon campaign, which took place from January 2014 to December 2015 near Manaus, Brazil, a city surrounded by natural forest for over 1000 km in every direction. City plumes are clearly identified by the strong enhancement of nucleation and Aitken mode particle concentrations over the clean background. As the plume traveled downwind, particle growth was observed, and is attributed to condensation of secondary species and coagulation (Fig.1). Observed aerosol growth is modeled using MOSAIC (Model for Simulating Aerosol Interactions and Chemistry), which dynamically partitions multiple compounds to all particle size bins by taking into account compound volatility, gas-phase diffusion, interfacial mass accommodation, particle-phase diffusion, and particle-phase reaction. The results from both wet and dry seasons will be discussed.

Analysis of Volatile Organic Compounds Emitted by Plant Growth-Promoting Fungus Phoma sp. GS8-3 for Growth Promotion Effects on Tobacco

PubMed Central

Naznin, Hushna Ara; Kimura, Minako; Miyazawa, Mitsuo; Hyakumachi, Mitsuro

2013-01-01

We extracted volatile organic compounds (VOCs) emitted by a plant growth-promoting fungus (PGPF) Phoma sp. GS8-3 by gas chromatography and identified them by mass spectrometry. All of the identified compounds belonged to C4-C8 hydrocarbons. Volatiles varied in number and quantity by the culture period of the fungus (in days). 2-Methyl-propanol and 3-methyl-butanol formed the main components of the volatile blends for all the culture periods of fungus. Growth-promoting effects of the identified synthetic compounds were analyzed individually and in blends using tobacco plants. We found that the mixture of volatiles extracted from 3-day-old culture showed significant growth promotion in tobacco in vitro. The volatile blend showed better growth promotion at lower than higher concentrations. Our results confirm the potential role of volatile organic compounds in the mechanism of growth enhancement by GS8-3. PMID:23080408

Variation of volatile compounds among wheat varieties and landraces.

PubMed

Starr, G; Petersen, M A; Jespersen, B M; Hansen, Å S

2015-05-01

Analysis of volatile compounds was performed on 81 wheat varieties and landraces, grown under controlled greenhouse conditions, in order to investigate the possibility of differentiating wheat varieties according to their volatile compound profiles. Volatile compounds from wheat samples were extracted by dynamic headspace extraction and analysed by gas chromatography-mass spectrometry. Seventy-two volatile compounds were identified in the wheat samples. Multivariate analysis of the data showed a large diversity in volatile profiles between samples. Differences occurred between samples from Austria compared to British, French and Danish varieties. Landraces were distinguishable from modern varieties and they were characterised by higher averaged peak areas for esters, alcohols, and some furans. Modern varieties were characterised by higher averaged peak areas for terpenes, pyrazines and straight-chained aldehydes. Differences in volatile profiles are demonstrated between wheat samples for the first time, based on variety. These results are significant to plant breeders and commercial users of wheat. Copyright © 2014 Elsevier Ltd. All rights reserved.

Volatile and non-volatile compounds in green tea affected in harvesting time and their correlation to consumer preference.

PubMed

Kim, Youngmok; Lee, Kwang-Geun; Kim, Mina K

2016-10-01

Current study was designed to find out how tea harvesting time affects the volatile and non-volatile compounds profiles of green tea. In addition, correlation of instrumental volatile and non-volatile compounds analyses to consumer perception were analyzed. Overall, earlier harvested green tea had stronger antioxidant capacity (~61.0%) due to the polyphenolic compounds from catechin (23,164 mg/L), in comparison to later harvested green teas (11,961 mg/L). However, high catechin content in green tea influenced negatively the consumer likings of green tea, due to high bitterness (27.6%) and astringency (13.4%). Volatile compounds drive consumer liking of green tea products were also identified, that included linalool, 2,3-methyl butanal, 2-heptanone, (E,E)-3,5-Octadien-2-one. Finding from current study are useful for green tea industry as it provide the difference in physiochemical properties of green tea harvested at different intervals.

Analysis of volatile organic compounds from illicit cocaine samples

NASA Astrophysics Data System (ADS)

Robins, W. H.; Wright, Bob W.

1994-10-01

Detection of illicit cocaine hydrochloride shipments can be improved if there is a greater understanding of the identity and quantity of volatile compounds present. This study provides preliminary data concerning the volatile organic compounds detected in a limited set of cocaine hydrochloride samples. In all cases, cocaine was one of the major volatile compounds detected. Other tropeines were detected in almost all samples. Low concentrations of compounds which may be residues of processing solvents were observed in some samples. The equilibrium emissivity of cocaine from cocaine hydrochloride was investigated and a value of 83 parts-per-trillion was determined.

75 FR 2090 - Approval and Promulgation of Air Quality Implementation Plans; Indiana; Volatile Organic Compound...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-14

... Promulgation of Air Quality Implementation Plans; Indiana; Volatile Organic Compound Automobile Refinishing... automobile refinishing rule for approval into its State Implementation Plan (SIP). These rule revisions extend the applicability of Indiana's approved volatile organic compound (VOC) automobile refinishing...

Potential Signatures of Semi-volatile Compounds Associated With Nuclear Processing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Probasco, Kathleen M.; Birnbaum, Jerome C.; Maughan, A. D.

2002-06-01

Semi-volatile chemicals associated with nuclear processes (e.g., the reprocessing of uranium to produce plutonium for nuclear weapons, or the separation of actinides from processing waste streams), can provide sticky residues or signatures that will attach to piping, ducting, soil, water, or other surface media. Volatile compounds, that are more suitable for electro-optical sensing, have been well studied. However, the semi-volatile compounds have not been well documented or studied. A majority of these semi-volatile chemicals are more robust than typical gaseous or liquid chemicals and can have lifetimes of several weeks, months, or years in the environment. However, large data gapsmore » exist concerning these potential signature compounds and more research is needed to fill these data gaps so that important signature information is not overlooked or discarded. This report investigates key semi-volatile compounds associated with nuclear separations, identifies available chemical and physical properties, and discusses the degradation products that would result from hydrolysis, radiolysis and oxidation reactions on these compounds.« less

Formation of volatile compounds during heating of spice paprika (Capsicum annuum) powder.

PubMed

Cremer, D R; Eichner, K

2000-06-01

Spice paprika (red pepper; Capsicum annuum) is the most cultivated spice worldwide and is used mainly for its color and pungency. However, current research is also focusing on the flavor as an important parameter. This paper deals with the kinetics of the formation of those volatiles that indicate a decrease in spice paprika quality due to Maillard reaction, hydrolytic reactions, and oxidative degradation reactions of lipids such as fatty acids and carotenoids. Spice paprika volatiles were quantitatively analyzed by means of headspace gas chromatography (HS-GC) and solid-phase microextraction (SPME) followed by gas chromatography-mass spectrometry (GC-MS). The kinetics of their formation were investigated, and the respective activation energies determined. Strecker aldehyde, acetone, and methanol formation followed a pseudo-zero-order reaction kinetic, and formation of dimethyl sulfide (DMS) was characterized by a first-order kinetic. The activation energies determined were between 86.3 and 101.8 for the Strecker aldehydes acetaldehyde (AA), 2-methylpropanal (2-MP), 3-methylbutanal (3-MB), and 2-methylbutanal (2-MB), 130.7 for acetone, 114.2 for methanol, and 109.7 kJ/mol for DMS. The amounts of Strecker aldehydes formed were correlated to the concentrations of the corresponding free amino acids present in the samples. The formation of hexanal and 6-methyl-5-hepten-2-one in Capsicum annuum during processing was confirmed, and the formation of beta-ionone was probably described for the first time. During heating, the concentration of hexanal increased rapidly. The formation of 6-methyl-5-hepten-2-one confirms that Capsicum annuum fruits contain lycopene.

[Behavioral response of Anopheles albimanus to volatile compounds collected inside houses from the south of Chiapas, Mexico].

PubMed

Ríos-Delgado, Silvany Mayoly; Rodríguez-Ramírez, Américo David; Cruz-López, Leopoldo; Escobar-Pérez, Luis Alonso; Aburto-Juárez, Ma de Lourdes; Torres-Estrada, José Luis

2008-01-01

To determine effects of volatile compounds in homes on the behavioral response of Anopheles albimanus. The study was conducted in January 2006, in the village of Nueva Independencia village, Suchiate, Chiapas. Volatile compounds were collected inside homes and the extracts were tested on unfed females in a Y-olfactometer. Extracts were analyzed in a gas chromatography-mass spectrometry system (GC-MS). Twenty eight extracts were obtained, twelve presented attraction and two repellency responses. GC-MS analyses of the extracts indicated variation in the volatile compound present in the extracts, but could not associated specific compounds with any particular effect. Within homes, volatiles presented attraction and repellency responses to An. albimanus. A definate pattern concerning the presence of a characteristic chemical compound and the observed response was not found.

Hydrodistillation-adsorption method for the isolation of water-soluble, non-soluble and high volatile compounds from plant materials.

PubMed

Mastelić, J; Jerković, I; Blazević, I; Radonić, A; Krstulović, L

2008-08-15

Proposed method of hydrodistillation-adsorption (HDA) on activated carbon and hydrodistillation (HD) with solvent trap were compared for the isolation of water-soluble, non-soluble and high volatile compounds, such as acids, monoterpenes, isothiocyanates and others from carob (Certonia siliqua L.), rosemary (Rosmarinus officinalis L.) and rocket (Eruca sativa L.). Isolated volatiles were analyzed by GC and GC/MS. The main advantages of HDA method over ubiquitous HD method were higher yields of volatile compounds and their simultaneous separation in three fractions that enabled more detail analyses. This method is particularly suitable for the isolation and analysis of the plant volatiles with high amounts of water-soluble compounds. In distinction from previously published adsorption of remaining volatile compounds from distillation water on activated carbon, this method offers simultaneous hydrodistillation and adsorption in the same apparatus.

Organosulfates as Tracers for Secondary Organic Aerosol (SOA) Formation from 2-Methyl-3-Buten-2 ol (MBO) in the Atmosphere

EPA Science Inventory

2-Methyl-3-buten-2-ol (MBO) is an important biogenic volatile organic compound (BVOC) emitted by pine trees and a potential precursor of atmospheric secondary organic aerosol (SOA) in forested regions. In the present study, hydroxyl radical (OH)-initiated oxidation of MBO was exa...

78 FR 29032 - Approval and Promulgation of Implementation Plans Tennessee: Revisions to Volatile Organic...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-17

... tropospheric ozone formation. The compounds were added by EPA through a rulemaking action which provided for... consistent with federal law. Tropospheric ozone, commonly known as smog, occurs when VOC and nitrogen oxide (NO X ) react in the atmosphere. Because of the harmful health effects of ozone, EPA limits the amount...

Natural Catalysts for Molten Cellulose Pyrolysis to Targeted Bio-Oils

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dauenhauer, Paul J.

2017-06-02

Catalysis of biomass biopolymer cellulose by alkaline earth metals is a fundamental chemistry relevant to energy processes including combustion, pyrolysis and gasification. In this work, the catalytic decomposition of cellulose by calcium ions was evaluated at high temperature (400-500°C) to elucidate the chemical mechanisms leading to the formation of volatile organic compounds.

40 CFR 60.441 - Definitions and symbols.

Code of Federal Regulations, 2011 CFR

2011-07-01

.... Fugitive volatile organic compounds means any volatile organic compounds which are emitted from the coating... capture fugitive volatile organic compounds. Oven means a chamber which uses heat or irradiation to bake... or label product. Solvent applied in the coating means all organic solvent contained in the adhesive...

40 CFR 60.441 - Definitions and symbols.

Code of Federal Regulations, 2013 CFR

2013-07-01

.... Fugitive volatile organic compounds means any volatile organic compounds which are emitted from the coating... capture fugitive volatile organic compounds. Oven means a chamber which uses heat or irradiation to bake... or label product. Solvent applied in the coating means all organic solvent contained in the adhesive...

40 CFR 60.441 - Definitions and symbols.

Code of Federal Regulations, 2012 CFR

2012-07-01

.... Fugitive volatile organic compounds means any volatile organic compounds which are emitted from the coating... capture fugitive volatile organic compounds. Oven means a chamber which uses heat or irradiation to bake... or label product. Solvent applied in the coating means all organic solvent contained in the adhesive...

40 CFR 60.441 - Definitions and symbols.

Code of Federal Regulations, 2014 CFR

2014-07-01

... = the weight fraction of organics applied of each coating (i) applied during a calendar month as.... Fugitive volatile organic compounds means any volatile organic compounds which are emitted from the coating... capture fugitive volatile organic compounds. Oven means a chamber which uses heat or irradiation to bake...

EMISSION OF VOLATILE COMPOUNDS BY SEEDS UNDER DIFFERENT ENVIRONMENTAL CONDITIONS

EPA Science Inventory

Small mammals locate buried wet seeds more efficiently than buried dry seeds. This may be attributable to emission of volatile compounds by the seeds. To test this hypothesis I measured emission of volatile compounds from seeds of three plant species (Pinus contorta, Purshia tr...

Non-thermal Plasma for VOC Treatment in Flue Gases

NASA Astrophysics Data System (ADS)

Ikaunieks, Janis; Mezmale, Liga; Zandeckis, Aivars; Pubule, Jelena; Blumberga, Andra; Veidenbergs, Ivars

2011-01-01

The paper discusses non-thermal plasmas, their generation and characteristics, formation mechanisms of ozone and the treatment of volatile organic compounds (VOCs). In the experimental part, undecane (C11H24 as model VOCs) was treated with assistance of low temperature plasma at an atmospheric pressure which was generated in the so-called stack reactor. The gas composition was 13% of oxygen in nitrogen with impurities of carbon dioxide, carbon monoxide and undecane. The formation of by-products, as well as the removal efficiency, were investigated.

Study on the behavior of heavy metals during thermal treatment of municipal solid waste (MSW) components.

PubMed

Yu, Jie; Sun, Lushi; Wang, Ben; Qiao, Yu; Xiang, Jun; Hu, Song; Yao, Hong

2016-01-01

Laboratory experiments were conducted to investigate the volatilization behavior of heavy metals during pyrolysis and combustion of municipal solid waste (MSW) components at different heating rates and temperatures. The waste fractions comprised waste paper (Paper), disposable chopstick (DC), garbage bag (GB), PVC plastic (PVC), and waste tire (Tire). Generally, the release trend of heavy metals from all MSW fractions in rapid-heating combustion was superior to that in low-heating combustion. Due to the different characteristics of MSW fractions, the behavior of heavy metals varied. Cd exhibited higher volatility than the rest of heavy metals. For Paper, DC, and PVC, the vaporization of Cd can reach as high as 75% at 500 °C in the rapid-heating combustion due to violent combustion, whereas a gradual increase was observed for Tire and GB. Zn and Pb showed a moderate volatilization in rapid-heating combustion, but their volatilities were depressed in slow-heating combustion. During thermal treatment, the additives such as kaolin and calcium can react or adsorb Pb and Zn forming stable metal compounds, thus decreasing their volatilities. The formation of stable compounds can be strengthened in slow-heating combustion. The volatility of Cu was comparatively low in both high and slow-heating combustion partially due to the existence of Al, Si, or Fe in residuals. Generally, in the reducing atmosphere, the volatility of Cd, Pb, and Zn was accelerated for Paper, DC, GB, and Tire due to the formation of elemental metal vapor. TG analysis also showed the reduction of metal oxides by chars forming elemental metal vapor. Cu2S was the dominant Cu species in reducing atmosphere below 900 °C, which was responsible for the low volatility of Cu. The addition of PVC in wastes may enhance the release of heavy metals, while GB and Tire may play an opposite effect. In controlling heavy metal emission, aluminosilicate- and calcium-based sorbents can be co-treated with fuels. Moreover, pyrolysis can be a better choice for treatment of solid waster in terms of controlling heavy metals. PVC and Tire should be separated and treated individually due to high possibility of heavy metal emission. This information may then serve as a guideline for the design of the subsequent gas cleaning plant, necessary to reduce the final emissions to the atmosphere to an acceptable level.

Volatile generation in bell peppers during frozen storage and thawing using selected ion flow tube mass spectrometry (SIFT-MS).

PubMed

Wampler, Brendan; Barringer, Sheryl A

2012-06-01

To determine volatile formation during storage and thawing, whole, pureed, blanched, and raw green and red bell peppers (Capsicum annuum) were frozen quickly or slowly then stored at -18 °C for up to 7 mo, with and without SnCl(2) addition during thawing. Headspace analysis was performed by a Selected Ion Flow Tube Mass Spectrometer (SIFT-MS). After blanching, (Z)-3-hexenal had a large significant decrease in concentration since it is a heat labile compound while most other volatiles did not change in concentration. The freezing process increased volatile levels in the puree only. Slow freeze peppers had higher levels of some LOX generated volatiles during storage than quick freeze. During frozen storage of blanched samples (E)-2-hexenal, (Z and E)-hexen-1-ol, and (E)-2-pentenal increased likely because of nonenzymatic autoxidation of fatty acids while other volatiles remained constant. In Raw Whole peppers, (Z)-3-hexenal, hexanal, and 2-pentylfuran were generated during storage likely because the LOX enzyme is still active during frozen storage. However, blanched samples had higher concentrations of (E)-2-hexenal, (Z and E)-hexen-1-ol, 1-penten-3-one, and (E)-2-heptenal because of enzymatic destruction of these volatiles in the raw samples. The levels of many of the volatiles in the raw samples, including (Z)-3-hexenal, (E)-2-hexenal, (Z and E)-hexen-1-ol, hexanal, (E)-2-pentenal, and 2-pentylfuran, appeared to peak around 34 d after freezing. Pureed samples had significantly higher levels of volatiles than the whole samples, and volatiles peaked earlier. Green bell pepper volatile levels were always higher than red bell pepper. Significantly higher volatile formation occurred during thawing than it did during frozen storage. Studying and monitoring the headspace volatiles with a SIFT-MS can give information that will help manufacturers better understand how the volatiles in bell peppers change during frozen storage. This will give valuable information to processors on how to minimize volatile changes during storage of frozen peppers. © 2012 Institute of Food Technologists®

ESTIMATING TRANSPORT AND DEPOSITION OF A SEMI-VOLATILE COMPOUND WITH A REGIONAL PHOTOCHEMICAL MODEL

EPA Science Inventory

To simulate the fate of compounds that are considered semi-volatile and toxic, we have modified a model for regional particulate matter. Our changes introduce a semi-volatile compound into the atmosphere as gaseous emissions from an area source. Once emitted, the gas can transf...

78 FR 22197 - Approval and Promulgation of Implementation Plans for Tennessee: Revisions to Volatile Organic...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-15

... Promulgation of Implementation Plans for Tennessee: Revisions to Volatile Organic Compound Definition AGENCY... total of 17 compounds to the list of compounds excluded from the definition of ``Volatile Organic...: Sean Lakeman, Regulatory Development Section, Air Planning Branch, Air, Pesticides and Toxics...

Potential of derived lunar volatiles for life support

NASA Technical Reports Server (NTRS)

Bula, R. J.; Wittenberg, L. J.; Tibbitts, T. W.; Kulcinski, G. L.

1992-01-01

The lunar regolith contains small quantities of solar wind implanted volatile compounds that have vital, basic uses for maintaining life support systems of lunar or space settlements. Recent proposals to utilize the helium-3 isotope (He-3) derived from the lunar regolith as a fuel for fusion reactors would result in the availability of large quantities of other lunar volatile compounds. The quantities obtained would provide the annual life support replacement requirements of 1150 to 23,000 inhabitants per ton of He-3 recovered, depending on the volatile compound. Utilization of the lunar volatile compounds for life support depends on the costs, in terms of materials and energy, associated with their extraction from the lunar regolith as compared to the delivery costs of these compounds from Earth resources. Considering today's conservative estimated transportation costs ($10,000 dollars per kilogram) and regolith mining costs ($5 dollars per ton), the life support replacement requirements could be more economically supplied by recovering the lunar volatile compounds than transporting these materials from Earth resources, even before He-3 will be utilized as a fusion fuel. In addition, availability of lunar volatile compounds could have a significant cost impact on maintaining the life support systems of the space station and a Mars base.

Analysis of volatile organic compounds of ‘Fuji’ apples following electron beam irradiation and storage

NASA Astrophysics Data System (ADS)

Song, Hyun-Pa; Shim, Sung-Lye; Lee, Sun-Im; Kim, Dong-Ho; Kwon, Joong-Ho; Kim, Kyong-Su

2012-08-01

The volatile organic compounds of non-irradiated and electron-beam irradiated 'Fuji' apples (Malus domestica Borkh.) at 0, 0.5, and 1 kGy were isolated through simultaneous distillation extractions and analyzed using gas chromatograph-mass spectrometry. A total of 53 volatile organic compounds were characterized in 0 and 1 kGy irradiated samples, whereas two more compounds related to ketone and terpenoid group were identified in 0.5 kGy irradiated samples. The contents of volatile compounds were 24.33, 36.49, and 35.28 mg/kg in 0, 0.5, and 1 kGy irradiated samples, respectively. The major compounds identified were butanol, hexanal, [E]-2-hexenal, and hexanol in all samples. The relative content of alcohol increased after 30 days of storage in all samples, whereas that of aldehyde decreased. Although the contents of some volatile compounds were changed by electron-beam irradiation, the total yield and major flavor compounds of irradiated 'Fuji' apples were similar to, or even greater than, those of the control. Therefore, the application of e-beam irradiation if required for microbial decontamination of 'Fuji' apples is an acceptable method as it does not bring about any major quantitative changes of volatile organic compounds.

Analysis of volatile organic compound from Elaeis guineensis inflorescences planted on different soil types in Malaysia

NASA Astrophysics Data System (ADS)

Muhamad Fahmi, M. H.; Ahmad Bukhary, A. K.; Norma, H.; Idris, A. B.

2016-11-01

The main attractant compound for Eleidobius kamerunicus to male spikelet Elaeis guineensis (oil palm) were determined by analyzing volatile organic compound extracted from E. guineenses inflorescences planted on different soil types namely peat soil, clay soil and sandy soil. Anthesizing male oil palm inflorescences were randomly choosen from palm aged between 4-5 years old age. Extraction of the volatiles from the oil palm inflorescences were performed by Accelerated Solvent Extraction method (ASE). The extracted volatile compound were determined by using gas chromatography-mass spectrometry. Out of ten identified compound, estragole was found to be a major compound in sandy soil (37.49%), clay soil (30.71%) and peat soil (27.79%). Other compound such as 9,12-octadecadieonic acid and n-hexadecanoic acid were found as major compound in peat soil (27.18%) and (7.45%); sandy soil (14.15 %) and (9.31%); and clay soil (30.23%) and (4.99%). This study shows that estragole was the predominant volatile compound detected in oil palm inflorescences with highly concentrated in palm planted in sandy soil type.

The contribution of evaporative emissions from gasoline vehicles to the volatile organic compound inventory in Mexico City.

PubMed

Schifter, I; Díaz, L; Rodríguez, R; González-Macías, C

2014-06-01

The strategy for decreasing volatile organic compound emissions in Mexico has been focused much more on tailpipe emissions than on evaporative emissions, so there is very little information on the contribution of evaporative emissions to the total volatile organic compound inventory. We examined the magnitudes of exhaust and evaporative volatile organic compound emissions, and the species emitted, in a representative fleet of light-duty gasoline vehicles in the Metropolitan Area of Mexico City. The US "FTP-75" test protocol was used to estimate volatile organic compound emissions associated with diurnal evaporative losses, and when the engine is started and a journey begins. The amount and nature of the volatile organic compounds emitted under these conditions have not previously been accounted in the official inventory of the area. Evaporative emissions from light-duty vehicles in the Metropolitan Area of Mexico City were estimated to be 39 % of the total annual amount of hydrocarbons emitted. Vehicles built before 1992 (16 % of the fleet) were found to be responsible for 43 % of the total hydrocarbon emissions from exhausts and 31 % of the evaporative emissions of organic compounds. The relatively high amounts of volatile organic compounds emitted from older vehicles found in this study show that strong emission controls need to be implemented in order to decrease the contribution of evaporative emissions of this fraction of the fleet.

New insights into the parametrization of temperature and light responses of mono - and sesquiterpene emissions from Aleppo pine and rosemary

NASA Astrophysics Data System (ADS)

Staudt, M.; Bourgeois, I.; Al Halabi, R.; Song, W.; Williams, J.

2017-03-01

Phytogenic emission of large volatile organic compounds (VOCs) such as monoterpenes (MTs) and sesquiterpenes (SQTs) are key precursors to the formation and growth of atmospheric particles. However, controlled environment studies to elucidate emission responses to temperature and light are still sparse. In this study, the volatile contents and emission responses of Aleppo pine and Rosemary have been investigated. These two common Mediterranean species store semivolatiles inside (resin ducts) and outside (trichomes) their foliage tissues respectively. Both species emitted mainly MTs with basal emission rates of around 5 (Rosemary) and 10 (pine) μg g-1 h-1 and SQTs about one order of magnitude lower. In Aleppo pine, two volatile sources could be clearly distinguished: 1) de-novo synthesized emission of (E)-β-ocimene and linalool, which accounted for about 70% of the total VOC release, were not found in foliar VOC extracts and expressed light dependency (LD) and temperature responses typical for enzyme driven emissions; and 2) storage-derived emissions of various MTs and SQTs whose emissions increased exponentially with temperature, showed no light dependency and were all present in leaf extracts. In Rosemary, all emitted MTs and SQTs including many oxygenated compounds, showed responses typical for stored volatiles and were all found in leaf extracts. The emissions of individual volatiles or volatile classes could be well described with the commonly applied empirical algorithms developed for LD or non LD emissions. However, the shapes of the temperature responses, and hence the deduced coefficient values, were significantly different between oxygenated and non-oxygenated compounds. They also differed between the storage-derived emissions of the two plant species, for individual VOCs or VOC classes. We address the possible reasons for this variation in temperature responses and argue that they are mostly due to molecular interactions along the species specific leaf-internal diffusion paths including the build-up of transient VOC pools and degradation.

Transformation of zinc hydroxide chloride monohydrate to crystalline zinc oxide.

PubMed

Moezzi, Amir; Cortie, Michael; McDonagh, Andrew

2016-04-25

Thermal decomposition of layered zinc hydroxide double salts provides an interesting alternative synthesis for particles of zinc oxide. Here, we examine the sequence of changes occurring as zinc hydroxide chloride monohydrate (Zn5(OH)8Cl2·H2O) is converted to crystalline ZnO by thermal decomposition. The specific surface area of the resultant ZnO measured by BET was 1.3 m(2) g(-1). A complicating and important factor in this process is that the thermal decomposition of zinc hydroxide chloride is also accompanied by the formation of volatile zinc-containing species under certain conditions. We show that this volatile compound is anhydrous ZnCl2 and its formation is moisture dependent. Therefore, control of atmospheric moisture is an important consideration that affects the overall efficiency of ZnO production by this process.

Volatile compounds and odor traits of dry-cured ham (Prosciutto crudo) irradiated by electron beam and gamma ray

USDA-ARS?s Scientific Manuscript database

Prosciutto crudo were irradiated at 0, 3 and 6kGy by gamma ray (GR) and electron beam (EB), respectively. The odor scores and volatile compounds were examined after 7 days storage at 4'. Volatile compounds from samples without and with irradiation at 6kGy were analyzed by GC-MS. Fifty-nine compounds...

Incremental Reactivity Effects on Secondary Organic Aerosol Formation in Urban Atmospheres with and without Biogenic Influence

NASA Astrophysics Data System (ADS)

Kacarab, Mary; Li, Lijie; Carter, William P. L.; Cocker, David R., III

2016-04-01

Two different surrogate mixtures of anthropogenic and biogenic volatile organic compounds (VOCs) were developed to study secondary organic aerosol (SOA) formation at atmospheric reactivities similar to urban regions with varying biogenic influence levels. Environmental chamber simulations were designed to enable the study of the incremental aerosol formation from select anthropogenic (m-Xylene, 1,2,4-Trimethylbenzene, and 1-Methylnaphthalene) and biogenic (α-pinene) precursors under the chemical reactivity set by the two different surrogate mixtures. The surrogate reactive organic gas (ROG) mixtures were based on that used to develop the maximum incremental reactivity (MIR) factors for evaluation of O3 forming potential. Multiple incremental aerosol formation experiments were performed in the University of California Riverside (UCR) College of Engineering Center for Environmental Research and Technology (CE-CERT) dual 90m3 environmental chambers. Incremental aerosol yields were determined for each of the VOCs studied and compared to yields found from single precursor studies. Aerosol physical properties of density, volatility, and hygroscopicity were monitored throughout experiments. Bulk elemental chemical composition from high-resolution time of flight aerosol mass spectrometer (HR-ToF-AMS) data will also be presented. Incremental yields and SOA chemical and physical characteristics will be compared with data from previous single VOC studies conducted for these aerosol precursors following traditional VOC/NOx chamber experiments. Evaluation of the incremental effects of VOCs on SOA formation and properties are paramount in evaluating how to best extrapolate environmental chamber observations to the ambient atmosphere and provides useful insights into current SOA formation models. Further, the comparison of incremental SOA from VOCs in varying surrogate urban atmospheres (with and without strong biogenic influence) allows for a unique perspective on the impacts different compounds have on aerosol formation in different urban regions.

Mechanisms of volatile production from non-sulfur amino acids by irradiation

NASA Astrophysics Data System (ADS)

Ahn, Dong Uk; Lee, Eun Joo; Feng, Xi; Zhang, Wangang; Lee, Ji Hwan; Jo, Cheorun; Nam, Kichang

2016-02-01

Non-sulfur amino acid monomers were used to study the mechanisms of volatile production in meat by irradiation. Irradiation not only produced many volatiles but also increased the amounts of volatiles from non-sulfur amino acid monomers. The major reaction mechanisms involved in volatile production from each group of the amino acids by irradiation differ significantly. However, we speculate that the radiolysis of amino acid side chains were the major mechanism. In addition, Strecker degradation, especially the production of aldehydes from aliphatic group amino acids, and deamination, isomerization, decarboxylation, cyclic reaction and dehydrogenation of the initial radiolytic products were also contributed to the production of volatile compounds. Each amino acid monomers produced different odor characteristics, but the intensities of odor from all non-sulfur amino acid groups were very weak. This indicated that the contribution of volatiles produced from non-sulfur amino acids was minor. If the volatile compounds from non-sulfur amino acids, especially aldehydes, interact with other volatiles compounds such as sulfur compounds, however, they can contribute to the off-odor of irradiated meat significantly.

SDE and SPME Analysis of Flavor Compounds in Jin Xuan Oolong Tea.

PubMed

Sheibani, Ershad; Duncan, Susan E; Kuhn, David D; Dietrich, Andrea M; O'Keefe, Sean F

2016-02-01

Simultaneous distillation-extraction (SDE) and solid phase micro extraction (SPME) are procedures used for the isolation of flavor compounds in foods. The purpose of this study was to optimize SDE conditions (solvent and time) and to compare SDE with SPME for the isolation of flavor compounds in Jin Xuan oolong tea using GC-MS and GC-O. The concentration of volatile compounds isolated with diethyl ether was higher (P < 0.05) than for dichloromethane and concentration was higher at 40 min (P < 0.05) than 20 or 60 min extractions. For SDE, 128 volatiles were identified using GC-MS and 45 aroma active compounds using GC-O. Trans-nerolidol was the most abundant compound in oolong tea. The number of volatiles identified using GC-MS was lower in SPME than SDE. For SPME, 59 volatiles and 41 aroma active compounds were identified. The composition of the volatiles isolated by the 2 methods differed considerably but provided complementary information. © 2016 Institute of Food Technologists®

Limited effect of anthropogenic nitrogen oxides on secondary organic aerosol formation

NASA Astrophysics Data System (ADS)

Zheng, Y.; Unger, N.; Hodzic, A.; Emmons, L.; Knote, C.; Tilmes, S.; Lamarque, J.-F.; Yu, P.

2015-12-01

Globally, secondary organic aerosol (SOA) is mostly formed from emissions of biogenic volatile organic compounds (VOCs) by vegetation, but it can be modified by human activities as demonstrated in recent research. Specifically, nitrogen oxides (NOx = NO + NO2) have been shown to play a critical role in the chemical formation of low volatility compounds. We have updated the SOA scheme in the global NCAR (National Center for Atmospheric Research) Community Atmospheric Model version 4 with chemistry (CAM4-chem) by implementing a 4-product volatility basis set (VBS) scheme, including NOx-dependent SOA yields and aging parameterizations. Small differences are found for the no-aging VBS and 2-product schemes; large increases in SOA production and the SOA-to-OA ratio are found for the aging scheme. The predicted organic aerosol amounts capture both the magnitude and distribution of US surface annual mean measurements from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network by 50 %, and the simulated vertical profiles are within a factor of 2 compared to aerosol mass spectrometer (AMS) measurements from 13 aircraft-based field campaigns across different regions and seasons. We then perform sensitivity experiments to examine how the SOA loading responds to a 50 % reduction in anthropogenic nitric oxide (NO) emissions in different regions. We find limited SOA reductions of 0.9-5.6, 6.4-12.0 and 0.9-2.8 % for global, southeast US and Amazon NOx perturbations, respectively. The fact that SOA formation is almost unaffected by changes in NOx can be largely attributed to a limited shift in chemical regime, to buffering in chemical pathways (low- and high-NOx pathways, O3 versus NO3-initiated oxidation) and to offsetting tendencies in the biogenic versus anthropogenic SOA responses.

Identification of volatile compounds in codfish ( Gadus) by a combination of two extraction Methods coupled with GC-MS analysis

NASA Astrophysics Data System (ADS)

Chang, Yufei; Hou, Hu; Li, Bafang

2016-06-01

Codfish is a kind of abyssal fish species with a great value in food industry. However, the flavor of codfish, especially the unpleasant odor, has caused serious problems in its processing. To accurately identify the volatile compounds in codfish, a combination of solid phase micro-extraction (SPME) method and simultaneous distillation extraction (SDE) method was used to extract the volatiles. Gas chromatography-mass spectrometry (GC-MS) along with Kovats indices (KI) and authentic standard compounds were used to identify the volatiles. The results showed that a total of 86 volatile compounds were identified in codfish, of them 24 were extracted by SDE, 69 compounds by SPME, and 10 compounds by both SDE and SPME. Seventy volatile compounds were found to have specific odors, of them 7 typical compounds contributed significantly to the flavor of codfish. Alcohols ( i.e., (E)-2-penten-1-ol and 2-octanol), esters ( i.e., ethyl butyrate and methyl geranate), aldehydes ( i.e., 2-dodecenal and pentadecanal) contributed the most to fresh flavor while nitrogen compounds, sulphur compounds, furans, as well as some ketones ( i.e., 2-hydroxy-3-pentanone) brought unpleasant odor, such as fishy and earthy odor. It was indicated that the combination of multiple extraction methods and GC-MS analysis can enhance the accuracy of identification, and provide a reference for the further study on flavor of aquatic products.

ASTROCULTURE(tm) Commercial Plant Growth Unit and Glove Box Insert

NASA Technical Reports Server (NTRS)

Zhou, Wei-Jia; Lambing, Steve (Technical Monitor)

2002-01-01

Two commercial plant investigations will be conducted during the STS-107 mission: living flower essential oil production and gene transfer. The research will be done using the ASTROCULTURE (trademark) hardware, which builds on similar experiments flown in the past on the space shuttle. This research will investigate how microgravity might affect the formation of the volatile chemical compounds - the essential oils - produced by two different types of living flowers. The flowers will be cultured in the ASTROCULTURE (trademark) plant chamber, which provides an enclosed and controlled environment. As the flowers bloom in space, they will produce essential oils, and these volatile compounds will be collected using International Flavors and Fragrance's proprietary Solid Phase Micro Extraction (SPME) technology. The gene transfer experiment examines a newly developed transformation system to see if it operates efficiently in the microgravity environment. This research is important for the development of genetically engineered crops, also known as transgenic crops.

Air monitoring of volatile organic compounds at relevant receptors during hydraulic fracturing operations in Washington County, Pennsylvania.

PubMed

Maskrey, Joshua R; Insley, Allison L; Hynds, Erin S; Panko, Julie M

2016-07-01

A 3-month air monitoring study was conducted in Washington County, Pennsylvania, at the request of local community members regarding the potential risks resulting from air emissions of pollutants related to hydraulic fracturing operations. Continuous air monitoring for total volatile organic compounds was performed at two sampling sites, including a school and a residence, located within 900 m of a hydraulic fracturing well pad that had been drilled prior to the study. Intermittent 24-hour air samples for 62 individual volatile organic compounds were also collected. The ambient air at both sites was monitored during four distinct periods of unconventional natural gas extraction activity: an inactive period prior to fracturing operations, during fracturing operations, during flaring operations, and during another inactive period after operations. The results of the continuous monitoring during fracturing and flaring sampling periods for total volatile organic compounds were similar to the results obtained during inactive periods. Total volatile organic compound 24-hour average concentrations ranged between 0.16 and 80 ppb during all sampling periods. Several individual volatile compounds were detected in the 24-hour samples, but they were consistent with background atmospheric levels measured previously at nearby sampling sites and in other areas in Washington County. Furthermore, a basic yet conservative screening level evaluation demonstrated that the detected volatile organic compounds were well below health-protective levels. The primary finding of this study was that the operation of a hydraulic fracturing well pad in Washington County did not substantially affect local air concentrations of total and individual volatile organic compounds.

Atmosphere-Ocean Coupling through Trace Gases

NASA Astrophysics Data System (ADS)

Tegtmeier, S.; Atlas, E. L.; Krüger, K.; Lennartz, S. T.; Marandino, C. A.; Patra, P. K.; Quack, B.; Schlundt, C.

2017-12-01

Halogen- and sulfur-containing trace gases, as well as other volatile organic compounds (VOCs, such as isoprene) from biogeochemical marine sources are important constituents of the ocean and the atmosphere. These compounds exert wide-ranging influence on atmospheric chemical processes and climate interactions, as well as on human health in coastal regions. In their reactive form, they can affect the oxidizing capacity of the air and lead to the formation of new particles or the growth of existing ones. In this contribution, marine derived halogen-, sulfur-, and oxygen-containing compounds will be discussed. Their net flux into the atmosphere and their impact on atmospheric processes is analyzed based on observations and model simulations.

Assessment of volatile compound profiles and the deduced sensory significance of virgin olive oils from the progeny of Picual×Arbequina cultivars.

PubMed

Pérez, Ana G; de la Rosa, Raúl; Pascual, Mar; Sánchez-Ortiz, Araceli; Romero-Segura, Carmen; León, Lorenzo; Sanz, Carlos

2016-01-08

Volatile compounds are responsible for most of the sensory qualities of virgin olive oil and they are synthesized when enzymes and substrates come together as olive fruit is crushed during the industrial process to obtain the oil. Here we have studied the variability among the major volatile compounds in virgin olive oil prepared from the progeny of a cross of Picual and Arbequina olive cultivars (Olea europaea L.). The volatile compounds were isolated by SPME, and analyzed by HRGC-MS and HRGC-FID. Most of the volatile compounds found in the progeny's oil are produced by the enzymes in the so-called lipoxygenase pathway, and they may be clustered into different groups according to their chain length and polyunsaturated fatty acid origin (linoleic and linolenic acids). In addition, a group of compounds derived from amino acid metabolism and two terpenes also contributed significantly to the volatile fraction, some of which had significant odor values in most of the genotypes evaluated. The volatile compound content of the progeny was very varied, widely transgressing the progenitor levels, suggesting that in breeding programs it might be more effective to consider a larger number of individuals within the same cross than using different crosses with fewer individuals. Multivariate analysis allowed genotypes with particularly interesting volatile compositions to be identified and their flavor quality deduced. Copyright © 2015 Elsevier B.V. All rights reserved.

Carbonyl compounds at Mount Tai in the North China Plain: Characteristics, sources, and effects on ozone formation

NASA Astrophysics Data System (ADS)

Yang, Xue; Xue, Likun; Yao, Lan; Li, Qinyi; Wen, Liang; Zhu, Yanhong; Chen, Tianshu; Wang, Xinfeng; Yang, Lingxiao; Wang, Tao; Lee, Shuncheng; Chen, Jianmin; Wang, Wenxing

2017-11-01

Carbonyl compounds, an important category of volatile organic compounds (VOCs), play important roles in ozone (O3) formation and atmospheric chemistry. To better understand the characteristics and sources of carbonyl compounds and their effects on O3 formation, C1-C8 carbonyls were measured at Mount Tai, the highest mountain in the North China Plain (NCP), in summer 2014. Acetone (3.57 ± 0.55 ppbv), formaldehyde (3.48 ± 0.98 ppbv) and acetaldehyde (1.27 ± 0.78 ppbv) are the three most abundant species, comprising as high as 90% of the total observed compounds. Isovaleraldehyde (0.37 ± 0.17 ppbv) presents another important carbonyl compound despite its high reactivity. Comparison with the observations available in China highlights the serious situation of carbonyls pollution in the NCP region. The sources of carbonyls are dominated by photo-oxidation of VOCs during the daytime and regional transport at night. Secondary sources from oxidation of hydrocarbons contribute on average 44% of formaldehyde, 31% of acetone, 85% of acetaldehyde, 78% of benzaldehyde, and 84% of isovaleraldehyde, demonstrating the dominant role of secondary formation in the ambient carbonyl levels. Formaldehyde, acetaldehyde and isovaleraldehyde are the most important contributors to the OH reactivity and O3 production among the measured carbonyls. This study shows that carbonyl compounds contribute significantly to the photochemical pollution in the NCP region and hence understanding their sources and characteristics is essential for developing the science-based O3 pollution control strategies.

Products and mechanism of secondary organic aerosol formation from reactions of n-alkanes with OH radicals in the presence of NOx.

PubMed

Lim, Yong Bin; Ziemann, Paul J

2005-12-01

Secondary organic aerosol (SOA) formation from reactions of n-alkanes with OH radicals in the presence of NOx was investigated in an environmental chamber using a thermal desorption particle beam mass spectrometer for particle analysis. SOA consisted of both first- and higher-generation products, all of which were nitrates. Major first-generation products were sigma-hydroxynitrates, while higher-generation products consisted of dinitrates, hydroxydinitrates, and substituted tetrahydrofurans containing nitrooxy, hydroxyl, and carbonyl groups. The substituted tetrahydrofurans are formed by a series of reactions in which sigma-hydroxycarbonyls isomerize to cyclic hemiacetals, which then dehydrate to form substituted dihydrofurans (unsaturated compounds) that quickly react with OH radicals to form lower volatility products. SOA yields ranged from approximately 0.5% for C8 to approximately 53% for C15, with a sharp increase from approximately 8% for C11 to approximately 50% for C13. This was probably due to an increase in the contribution of first-generation products, as well as other factors. For example, SOA formed from the C10 reaction contained no first-generation products, while for the C15 reaction SOA was approximately 40% first-generation and approximately 60% higher-generation products, respectively. First-generation sigma-hydroxycarbonyls are especially important in SOA formation, since their subsequent reactions can rapidly form low volatility compounds. In the atmosphere, substituted dihydrofurans created from sigma-hydroxycarbonyls will primarily react with O3 or NO3 radicals, thereby opening reaction pathways not normally accessible to saturated compounds.

Volatile compounds of young wines from cabernet sauvignon, cabernet gernischet and chardonnay varieties grown in the loess plateau region of china.

PubMed

Jiang, Bao; Zhang, Zhenwen

2010-12-10

In order to elucidate the aroma components of wine produced in the Loess Plateau region of China, volatile compounds of young wines from Cabernet Sauvignon, Cabernet Gernischet and Chardonnay varieties grown in the new ecological region were investigated for the first time in this research. Among the volatile compounds analyzed by HS-SPME with GC-MS, a total of 45, 44 and 42 volatile compounds were identified and quantified in Cabernet Sauvignon, Cabernet Gernischet and Chardonnay wines, respectively. In the volatiles detected, alcohols formed the most abundant group in the aroma compounds of the three wines, followed by esters and fatty acids. According to their odor active values (OAVs), 18 volatile compounds were always present in the three wines at concentrations higher than their threshold values, but ethyl octanoate, ethyl hexanoate, and isoamyl acetate were found to jointly contribute to 92.9%, 93.3%, and 98.7%, of the global aroma of Cabernet Sauvignon, Cabernet Gernischet and Chardonnay wines, respectively. These odorants are associated with "fruity'' and ''ripe fruit'' odor descriptors.

Field guide for collecting samples for analysis of volatile organic compounds in stream water for the National Water-Quality Assessment Program

USGS Publications Warehouse

Shelton, Larry R.

1997-01-01

For many years, stream samples for analysis of volatile organic compounds have been collected without specific guidelines or a sampler designed to avoid analyte loss. In 1996, the U.S. Geological Survey's National Water-Quality Assessment Program began aggressively monitoring urban stream-water for volatile organic compounds. To assure representative samples and consistency in collection procedures, a specific sampler was designed to collect samples for analysis of volatile organic compounds in stream water. This sampler, and the collection procedures, were tested in the laboratory and in the field for compound loss, contamination, sample reproducibility, and functional capabilities. This report describes that sampler and its use, and outlines field procedures specifically designed to provide contaminant-free, reproducible volatile organic compound data from stream-water samples. These guidelines and the equipment described represent a significant change in U.S. Geological Survey instructions for collecting and processing stream-water samples for analysis of volatile organic compounds. They are intended to produce data that are both defensible and interpretable, particularly for concentrations below the microgram-per-liter level. The guidelines also contain detailed recommendations for quality-control samples.

Volatiles in Inter-Specific Bacterial Interactions

PubMed Central

Tyc, Olaf; Zweers, Hans; de Boer, Wietse; Garbeva, Paolina

2015-01-01

The importance of volatile organic compounds for functioning of microbes is receiving increased research attention. However, to date very little is known on how inter-specific bacterial interactions effect volatiles production as most studies have been focused on volatiles produced by monocultures of well-described bacterial genera. In this study we aimed to understand how inter-specific bacterial interactions affect the composition, production and activity of volatiles. Four phylogenetically different bacterial species namely: Chryseobacterium, Dyella, Janthinobacterium, and Tsukamurella were selected. Earlier results had shown that pairwise combinations of these bacteria induced antimicrobial activity in agar media whereas this was not the case for monocultures. In the current study, we examined if these observations were also reflected by the production of antimicrobial volatiles. Thus, the identity and antimicrobial activity of volatiles produced by the bacteria were determined in monoculture as well in pairwise combinations. Antimicrobial activity of the volatiles was assessed against fungal, oomycetal, and bacterial model organisms. Our results revealed that inter-specific bacterial interactions affected volatiles blend composition. Fungi and oomycetes showed high sensitivity to bacterial volatiles whereas the effect of volatiles on bacteria varied between no effects, growth inhibition to growth promotion depending on the volatile blend composition. In total 35 volatile compounds were detected most of which were sulfur-containing compounds. Two commonly produced sulfur-containing volatile compounds (dimethyl disulfide and dimethyl trisulfide) were tested for their effect on three target bacteria. Here, we display the importance of inter-specific interactions on bacterial volatiles production and their antimicrobial activities. PMID:26733959

Changes in volatile compound composition of Antrodia camphorata during solid state fermentation.

PubMed

Xia, Yongjun; Zhang, Baorong; Li, Weijiang; Xu, Ganrong

2011-10-01

Although the volatiles present in mushrooms and fungi have been investigated by many researchers, including Antrodia camphorata in submerged fermentation, there are few data available regarding changes in volatile compounds during fermentation. Our research has revealed that solid state fermentation of A. camphorata is highly odiferous compared with submerged cultures and the odor changed with increasing culture time. Therefore the aim of this study was to investigate the changes in volatile compound composition of A. camphorata during solid state fermentation. Altogether, 124 major volatile compounds were identified. The volatile compounds produced by A. camphorata during growth in solid state fermentation were quite different. Oct-1-en-3-ol, octan-3-one and methyl 2-phenylacetate were predominant in exponential growth phase production, while the dominant volatiles produced in stationary phase were octan-3-one and methyl 2-phenylacetate. In stationary phase, lactone compounds in A. camphorata, such as 5-butyloxolan-2-one, 5-heptyloxolan-2-one, 6-heptyloxan-2-one, contributed greatly to peach and fruit-like flavor. Terpene and terpene alcohol compounds, such as 1-terpineol, L-linalool, T-cadinol, (E, E)-farnesol, β-elemene, cis-α-bisabolene and α-muurolene, made different contributions to herbal fresh aroma in A. camphorata. Nineteen volatile sesquiterpenes were detected from solid state fermentation of A. camphorata. The compounds 5-n-butyl-5H-furan-2-one, β-ionone, (-)-caryophyllene oxide, aromadendrene oxide, diepi-α-cedrene epoxide, β-elemene, α-selinene, α-muurolene, azulene, germacrene D, γ-cadinene and 2-methylpyrazine have not hitherto been reported in A. camphorata. The preliminary results suggest that the aroma-active compounds produced by A camphorata in solid state fermentation might serve as an important source of natural aroma compounds for the food and cosmetic industries or antibiotic activity compounds. The sesquiterpenes could be identified as possible taxonomic markers for A. camphorata. Copyright © 2011 Society of Chemical Industry.

Determination of some volatile compounds in alcoholic beverage by headspace solid-phase microextraction gas chromatography - mass spectrometry

NASA Astrophysics Data System (ADS)

Schmutzer, G.; Avram, V.; Feher, I.; David, L.; Moldovan, Z.

2012-02-01

The volatile composition of alcoholic beverage was studied by headspace solid-phase microextraction (HSSPME) method and gas chromatography - mass spectrometry (GC-MS). Some volatile compounds, such as alcohols, esters, terpenes and other are mainly responsible for the flavor of fortified wines and their amounts specify the quality of the alcoholic beverages. From this perspective it is interesting to develop a rapid, selective and sensitive analytical method suitable for simultaneous quantification of the main molecules being responsible for the organoleptic characteristic of alcoholic beverages. Vermouth fortified drink was analyzed in order to characterize the volatile profile. Using the HS-SPME/GC-MS a number of twenty-six volatile compounds from a commercial market alcoholic beverage were identified. The most abundant compounds were m-thymol, o-thymol and eugenol, alongside of the ethyl ester compounds.

Biochemistry of Apple Aroma: A Review.

PubMed

Espino-Díaz, Miguel; Sepúlveda, David Roberto; González-Aguilar, Gustavo; Olivas, Guadalupe I

2016-12-01

Flavour is a key quality attribute of apples defined by volatile aroma compounds. Biosynthesis of aroma compounds involves metabolic pathways in which the main precursors are fatty and amino acids, and the main products are aldehydes, alcohols and esters. Some enzymes are crucial in the production of volatile compounds, such as lipoxygenase, alcohol dehydrogenase, and alcohol acyltransferase. Composition and concentration of volatiles in apples may be altered by pre- and postharvest factors that cause a decline in apple flavour. Addition of biosynthetic precursors of volatile compounds may be a strategy to promote aroma production in apples. The present manuscript compiles information regarding the biosynthesis of volatile aroma compounds, including metabolic pathways, enzymes and substrates involved, factors that may affect their production and also includes a wide number of studies focused on the addition of biosynthetic precursors in their production.

Biochemistry of Apple Aroma: A Review

PubMed Central

Espino-Díaz, Miguel; Sepúlveda, David Roberto; González-Aguilar, Gustavo

2016-01-01

Summary Flavour is a key quality attribute of apples defined by volatile aroma compounds. Biosynthesis of aroma compounds involves metabolic pathways in which the main precursors are fatty and amino acids, and the main products are aldehydes, alcohols and esters. Some enzymes are crucial in the production of volatile compounds, such as lipoxygenase, alcohol dehydrogenase, and alcohol acyltransferase. Composition and concentration of volatiles in apples may be altered by pre- and postharvest factors that cause a decline in apple flavour. Addition of biosynthetic precursors of volatile compounds may be a strategy to promote aroma production in apples. The present manuscript compiles information regarding the biosynthesis of volatile aroma compounds, including metabolic pathways, enzymes and substrates involved, factors that may affect their production and also includes a wide number of studies focused on the addition of biosynthetic precursors in their production. PMID:28115895

Volatile organic compounds speciation and their influence on ozone formation potential in an industrialized urban area in Brazil.

PubMed

Galvão, Elson Silva; Santos, Jane Meri; Reis Junior, Neyval Costa; Stuetz, Richard Michael

2016-09-01

Speciation and the influence on the ozone formation potential (OFP) from volatile organic compounds (VOCs) have been studied between February June 2013 in Vitória, ES, Brazil. Passive samplers were installed at three air-quality monitoring stations and a total of 96 samplings were collected. A total of 78 VOCs were characterized by gas chromatograph-mass spectrometer. The predominant group was organic acids, followed by alcohols and substituted aromatics and 14 precursor species were quantified. An analysis correlating concentrations with wind direction was conducted to identify possible sources. The OFP was calculated applying the scale of maximum incremental reactivity proposed by Carter.[ 23 ] Ozone precursors with the greatest OFP such as undecane, toluene, ethylbenzene and m, p-xylene compounds were the most abundant with means of 0.855, 0.365, 0.259 and 0.289 µg m(-3), respectively. The benzene, toluene, ethylbenzene and xylene (BTEX) group was found below the limits considered harmful to the health of the population living in Vitória. The OFP calculated for the precursors group was 22.55 µg m(-3) for the rainy season and 32.11 µg m(-3) for the dry season. The VOC/NOx ratio in Vitória is approximately 1.71, indicating that the region has a VOC-limiting condition for the production of ozone.

The volatile compound BinBase mass spectral database.

PubMed

Skogerson, Kirsten; Wohlgemuth, Gert; Barupal, Dinesh K; Fiehn, Oliver

2011-08-04

Volatile compounds comprise diverse chemical groups with wide-ranging sources and functions. These compounds originate from major pathways of secondary metabolism in many organisms and play essential roles in chemical ecology in both plant and animal kingdoms. In past decades, sampling methods and instrumentation for the analysis of complex volatile mixtures have improved; however, design and implementation of database tools to process and store the complex datasets have lagged behind. The volatile compound BinBase (vocBinBase) is an automated peak annotation and database system developed for the analysis of GC-TOF-MS data derived from complex volatile mixtures. The vocBinBase DB is an extension of the previously reported metabolite BinBase software developed to track and identify derivatized metabolites. The BinBase algorithm uses deconvoluted spectra and peak metadata (retention index, unique ion, spectral similarity, peak signal-to-noise ratio, and peak purity) from the Leco ChromaTOF software, and annotates peaks using a multi-tiered filtering system with stringent thresholds. The vocBinBase algorithm assigns the identity of compounds existing in the database. Volatile compound assignments are supported by the Adams mass spectral-retention index library, which contains over 2,000 plant-derived volatile compounds. Novel molecules that are not found within vocBinBase are automatically added using strict mass spectral and experimental criteria. Users obtain fully annotated data sheets with quantitative information for all volatile compounds for studies that may consist of thousands of chromatograms. The vocBinBase database may also be queried across different studies, comprising currently 1,537 unique mass spectra generated from 1.7 million deconvoluted mass spectra of 3,435 samples (18 species). Mass spectra with retention indices and volatile profiles are available as free download under the CC-BY agreement (http://vocbinbase.fiehnlab.ucdavis.edu). The BinBase database algorithms have been successfully modified to allow for tracking and identification of volatile compounds in complex mixtures. The database is capable of annotating large datasets (hundreds to thousands of samples) and is well-suited for between-study comparisons such as chemotaxonomy investigations. This novel volatile compound database tool is applicable to research fields spanning chemical ecology to human health. The BinBase source code is freely available at http://binbase.sourceforge.net/ under the LGPL 2.0 license agreement.

The volatile compound BinBase mass spectral database

PubMed Central

2011-01-01

Background Volatile compounds comprise diverse chemical groups with wide-ranging sources and functions. These compounds originate from major pathways of secondary metabolism in many organisms and play essential roles in chemical ecology in both plant and animal kingdoms. In past decades, sampling methods and instrumentation for the analysis of complex volatile mixtures have improved; however, design and implementation of database tools to process and store the complex datasets have lagged behind. Description The volatile compound BinBase (vocBinBase) is an automated peak annotation and database system developed for the analysis of GC-TOF-MS data derived from complex volatile mixtures. The vocBinBase DB is an extension of the previously reported metabolite BinBase software developed to track and identify derivatized metabolites. The BinBase algorithm uses deconvoluted spectra and peak metadata (retention index, unique ion, spectral similarity, peak signal-to-noise ratio, and peak purity) from the Leco ChromaTOF software, and annotates peaks using a multi-tiered filtering system with stringent thresholds. The vocBinBase algorithm assigns the identity of compounds existing in the database. Volatile compound assignments are supported by the Adams mass spectral-retention index library, which contains over 2,000 plant-derived volatile compounds. Novel molecules that are not found within vocBinBase are automatically added using strict mass spectral and experimental criteria. Users obtain fully annotated data sheets with quantitative information for all volatile compounds for studies that may consist of thousands of chromatograms. The vocBinBase database may also be queried across different studies, comprising currently 1,537 unique mass spectra generated from 1.7 million deconvoluted mass spectra of 3,435 samples (18 species). Mass spectra with retention indices and volatile profiles are available as free download under the CC-BY agreement (http://vocbinbase.fiehnlab.ucdavis.edu). Conclusions The BinBase database algorithms have been successfully modified to allow for tracking and identification of volatile compounds in complex mixtures. The database is capable of annotating large datasets (hundreds to thousands of samples) and is well-suited for between-study comparisons such as chemotaxonomy investigations. This novel volatile compound database tool is applicable to research fields spanning chemical ecology to human health. The BinBase source code is freely available at http://binbase.sourceforge.net/ under the LGPL 2.0 license agreement. PMID:21816034

A method for the solvent extraction of low-boiling-point plant volatiles.

PubMed

Xu, Ning; Gruber, Margaret; Westcott, Neil; Soroka, Julie; Parkin, Isobel; Hegedus, Dwayne

2005-01-01

A new method has been developed for the extraction of volatiles from plant materials and tested on seedling tissue and mature leaves of Arabidopsis thaliana, pine needles and commercial mixtures of plant volatiles. Volatiles were extracted with n-pentane and then subjected to quick distillation at a moderate temperature. Under these conditions, compounds such as pigments, waxes and non-volatile compounds remained undistilled, while short-chain volatile compounds were distilled into a receiving flask using a high-efficiency condenser. Removal of the n-pentane and concentration of the volatiles in the receiving flask was carried out using a Vigreux column condenser prior to GC-MS. The method is ideal for the rapid extraction of low-boiling-point volatiles from small amounts of plant material, such as is required when conducting metabolic profiling or defining biological properties of volatile components from large numbers of mutant lines.

The Influence of Spices on the Volatile Compounds of Cooked Beef Patty

PubMed Central

Jung, Samooel; Jo, Cheorun; Kim, Il Suk; Nam, Ki Chang; Ahn, Dong Uk

2014-01-01

The aim of this study is to examine the influences of spices on the amounts and compositions of volatile compounds released from cooked beef patty. Beef patty with 0.5% of spice (nutmeg, onion, garlic, or ginger powder, w/w) was cooked by electronic pan until they reached an internal temperature of 75℃. A total of 46 volatile compounds (6 alcohols, 6 aldehydes, 5 hydrocarbons, 6 ketones, 9 sulfur compounds, and 14 terpenes) from cooked beef patties were detected by using purgeand- trap GC/MS. The addition of nutmeg, onion, or ginger powder significantly reduced the production of the volatile compounds via lipid oxidation in cooked beef patty when compared to those from the control. Also, the addition of nutmeg and garlic powder to beef patty generated a lot of trepans or sulfur volatile compounds, respectively. From these results, the major proportion by chemical classes such as alcohols, aldehydes, hydrocarbons, ketones, sulfur compounds, and terpenes was different depending on the spice variations. The results indicate that addition of spices to the beef patty meaningfully changes the volatile compounds released from within. Therefore, it can be concluded that spices can interact with meat aroma significantly, and thus, the character of each spice should be considered before adding to the beef patty. PMID:26760934

The Influence of Spices on the Volatile Compounds of Cooked Beef Patty.

PubMed

Jung, Samooel; Jo, Cheorun; Kim, Il Suk; Nam, Ki Chang; Ahn, Dong Uk; Lee, Kyung Heang

2014-01-01

The aim of this study is to examine the influences of spices on the amounts and compositions of volatile compounds released from cooked beef patty. Beef patty with 0.5% of spice (nutmeg, onion, garlic, or ginger powder, w/w) was cooked by electronic pan until they reached an internal temperature of 75℃. A total of 46 volatile compounds (6 alcohols, 6 aldehydes, 5 hydrocarbons, 6 ketones, 9 sulfur compounds, and 14 terpenes) from cooked beef patties were detected by using purgeand- trap GC/MS. The addition of nutmeg, onion, or ginger powder significantly reduced the production of the volatile compounds via lipid oxidation in cooked beef patty when compared to those from the control. Also, the addition of nutmeg and garlic powder to beef patty generated a lot of trepans or sulfur volatile compounds, respectively. From these results, the major proportion by chemical classes such as alcohols, aldehydes, hydrocarbons, ketones, sulfur compounds, and terpenes was different depending on the spice variations. The results indicate that addition of spices to the beef patty meaningfully changes the volatile compounds released from within. Therefore, it can be concluded that spices can interact with meat aroma significantly, and thus, the character of each spice should be considered before adding to the beef patty.

Changes in Volatile Compounds of Chinese Luzhou-Flavor Liquor during the Fermentation and Distillation Process.

PubMed

Ding, Xiaofei; Wu, Chongde; Huang, Jun; Zhou, Rongqing

2015-11-01

The aim of this study was to investigate the dynamic of volatile compounds in the Zaopei during the fermentation and distillation process by headspace solid-phase microextraction-gas chromatography mass spectrometry (HS-SPME-GCMS). Physicochemical properties analysis of Zaopei (fermented grains [FG], fermented grains mixed with sorghum [FGS], streamed grains [SG], and streamed grains mixed with Daqu [SGD]) showed distinct changes. A total number of 66 volatile compounds in the Zaopei were identified, in which butanoic acid, hexanoic acid, ethyl hexanoate, ethyl lactate, ethyl octanoate, hexyl hexanoate, ethyl hydrocinnamate, ethyl oleate, ethyl hexadecanoate, and ethyl linoleate were considered to be the dominant compounds due to their high concentrations. FG had the highest volatile compounds (112.43 mg/kg), which significantly decreased by 17.05% in the FGS, 67.12% in the SG, and 73.75% in the SGD. Furthermore, about 61.49% of volatile compounds of FGS were evaporated into raw liquor, whereas head, heart, and tail liquor accounted for 29.84%, 39.49%, and 30.67%, respectively. Each volatile class generally presented a decreasing trend, except for furans. Especially, the percentage of esters was 55.51% to 67.41% in the Zaopei, and reached 92.60% to 97.67% in the raw liquor. Principal component analysis based ordination of volatile compounds data segregated FGS and SGD samples. In addition, radar diagrams of the odor activity values suggested that intense flavor of fruit was weakened most from FG to SGD. The dynamic of volatile compounds in the Zaopei during the fermentation and distillation process was tested by SPME-GCMS. The result of this study demonstrated that both volatile compounds of Zaopei and thermal reaction during distillation simply determined the unique feature of raw liquor. This study was conducted based on the real products from liquor manufactory, so it is practicable that the method can be used in an industry setting. © 2015 Institute of Food Technologists®

Fig volatile compounds--a first comparative study.

PubMed

Grison-Pigé, Laure; Hossaert-McKey, Martine; Greeff, Jaco M; Bessière, Jean-Marie

2002-09-01

We analysed the compounds of volatile blends released by receptive figs of twenty Ficus species to attract their specific pollinating wasps. In all, 99 different compounds were identified. The compounds are mainly terpenoids, aliphatic compounds and products from the shikimic acid pathway. In each species blend, there are few major compounds, which are generally common among floral fragrances. Most species blends also include rare compounds, but generally their proportion in the blend is low. A possible basis for species-specificity of Ficus-wasp interactions is discussed in relation to the patterns of volatiles found in this interspecies comparison. Copyright 2002 Elsevier Science Ltd.

Monitoring of selected skin- and breath-borne volatile organic compounds emitted from the human body using gas chromatography ion mobility spectrometry (GC-IMS).

PubMed

Mochalski, Paweł; Wiesenhofer, Helmut; Allers, Maria; Zimmermann, Stefan; Güntner, Andreas T; Pineau, Nicolay J; Lederer, Wolfgang; Agapiou, Agapios; Mayhew, Christopher A; Ruzsanyi, Veronika

2018-02-15

Human smuggling and associated cross-border crimes have evolved as a major challenge for the European Union in recent years. Of particular concern is the increasing trend of smuggling migrants hidden inside shipping containers or trucks. Therefore, there is a growing demand for portable security devices for the non-intrusive and rapid monitoring of containers to detect people hiding inside. In this context, chemical analysis of volatiles organic compounds (VOCs) emitted from the human body is proposed as a locating tool. In the present study, an in-house made ion mobility spectrometer coupled with gas chromatography (GC-IMS) was used to monitor the volatile moieties released from the human body under conditions that mimic entrapment. A total of 17 omnipresent volatile compounds were identified and quantified from 35 ion mobility peaks corresponding to human presence. These are 7 aldehydes (acrolein, 2-methylpropanal, 3-methylbutanal, 2-ethacrolein, n-hexanal, n-heptanal, benzaldehyde), 3 ketones (acetone, 2-pentanone, 4-methyl-2-pentanone), 5 esters (ethyl formate, ethyl propionate, vinyl butyrate, butyl acetate, ethyl isovalerate), one alcohol (2-methyl-1-propanol) and one organic acid (acetic acid). The limits of detection (0.05-7.2 ppb) and relative standard deviations (0.6-11%) should be sufficient for detecting these markers of human presence in field conditions. This study shows that GC-IMS can be used as a portable field detector of hidden or entrapped people. Copyright © 2018 Elsevier B.V. All rights reserved.

Remedial Investigation/Feasibility Study/Interim Response Actions

DTIC Science & Technology

1988-03-25

organosulfur compounds (CC/FP), organophosphorus compounds (CC/FPD), hydrocarbons (CC/FID), volatile aromatic compounds (GC/ PID ), volatile halogenated...ICP metals, mercury and arsenic (AA). Water samples are being analyzed for volatile halogenated organics (GC/CON), volatile aromatic organics (GC/ PID ...Feb Mar Apr May Jun Jul Aug SepSI - I I I I I • .. I I I ----+----- 685 27-90 so ONSITE DISPOSAL FACILITY .i * 686 27-01 Prep FLUE Plan Fz=m8u> 6e7

Characterization of the volatile profiles of beer using headspace solid-phase microextraction and gas chromatography-mass spectrometry.

PubMed

Rossi, Serena; Sileoni, Valeria; Perretti, Giuseppe; Marconi, Ombretta

2014-03-30

The objective of this study was a multivariate characterization of the volatile profile of beers. Such a characterization is timely considering the increasing worldwide consumption of beer, the continuous growth of microbreweries and the importance of volatile compounds to beer flavour. A method employing solid-phase microextraction and gas chromatography-mass spectrometry (SPME-GC-MS) was optimized and then applied to a sample set of 36 industrial and craft beers of various styles and fermentation types. The volatile profiles of different beer styles is described, with particular attention paid to the volatile compounds characteristic of a spontaneously fermented lambic raspberry framboise beer. Furthermore, it was also possible to identify which specific volatile compounds are principally responsible for the differences in the volatile profiles of top- and bottom-fermented beers. Moreover, a volatile fingerprint of the craft top-fermented Italian beers was defined, as they show a very similar volatile profile. Finally, the volatile compounds that are characteristic of the bock-style beers are described. The SPME-GC-MS analytical method optimized in this study is suitable for characterizing the volatile fingerprint of different beers, especially on the basis of the kind of fermentation (top, bottom or spontaneous), the method of production and the style of the beer. © 2013 Society of Chemical Industry.

Offpost Operable Unit Remedial Investigation. Final Addendum. Volume 1

DTIC Science & Technology

1992-03-30

41 3.2.1.1.7 Other Volatile Organic Compounds ............. 48 3.2.1.2 Unconfined Flow System Inorganics ..................... 48 3.2.2...Formation Inorganics ........................ 56 3.2.3 Summary of Gas Chromatography/Mass Spectroscopy Results ......... 58 3.2.4 Summary of Quality...WATER CONTAMINATION ...... 64 4.1.1 O rganic Com pounds ........................................ 65 4.1.2 Inorganic Constituents

Malodorous volatile organic sulfur compounds: Sources, sinks and significance in inland waters.

PubMed

Watson, Susan B; Jüttner, Friedrich

2017-03-01

Volatile Organic Sulfur Compounds (VOSCs) are instrumental in global S-cycling and greenhouse gas production. VOSCs occur across a diversity of inland waters, and with widespread eutrophication and climate change, are increasingly linked with malodours in organic-rich waterbodies and drinking-water supplies. Compared with marine systems, the role of VOSCs in biogeochemical processes is far less well characterized for inland waters, and often involves different physicochemical and biological processes. This review provides an updated synthesis of VOSCs in inland waters, focusing on compounds known to cause malodours. We examine the major limnological and biochemical processes involved in the formation and degradation of alkylthiols, dialkylsulfides, dialkylpolysulfides, and other organosulfur compounds under different oxygen, salinity and mixing regimes, and key phototropic and heterotrophic microbial producers and degraders (bacteria, cyanobacteria, and algae) in these environs. The data show VOSC levels which vary significantly, sometimes far exceeding human odor thresholds, generated by a diversity of biota, biochemical pathways, enzymes and precursors. We also draw attention to major issues in sampling and analytical artifacts which bias and preclude comparisons among studies, and highlight significant knowledge gaps that need addressing with careful, appropriate methods to provide a more robust understanding of the potential effects of continued global development.

Source, impact and removal of malodour from soiled clothing.

PubMed

Denawaka, Chamila J; Fowlis, Ian A; Dean, John R

2016-03-18

Static headspace--multi-capillary column--gas chromatography--ion mobility spectrometry (SHS-MCC-GC-IMS) has been applied to the analysis of malodour compounds from soiled clothing (socks and T-shirts), pre- and post washing, at low temperature (20°C). Six volatile compounds (VCs) (i.e. butyric acid, dimethyl disulfide, dimethyl trisulfide, 2-heptanone, 2-nonanone and 2-octanone) were identified. After sensory evaluation of soiled garments they were subjected to laundering with non-perfumed washing powder. The efficiency of the laundering process was evaluated by determining the reduction of each detected volatile compound (VC) post-wash (damp) for socks and T-shirts; VC concentration reductions of between 16 and 100% were noted, irrespective of sample type. Additionally the T-shirt study considered the change in VC concentration post-wash (dry) i.e. after the drying process at ambient temperature. Overall VC concentration reductions of between 25 and 98% were noted for T-shirt samples pre-wash to post-wash (dry). Finally, a potential biochemical metabolic pathway for the formation of malodour compounds associated with bacteria in axillary sweat is proposed. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

How salt lakes affect atmospheric new particle formation: A case study in Western Australia.

PubMed

Kamilli, K A; Ofner, J; Krause, T; Sattler, T; Schmitt-Kopplin, P; Eitenberger, E; Friedbacher, G; Lendl, B; Lohninger, H; Schöler, H F; Held, A

2016-12-15

New particle formation was studied above salt lakes in-situ using a mobile aerosol chamber set up above the salt crust and organic-enriched layers of seven different salt lakes in Western Australia. This unique setup made it possible to explore the influence of salt lake emissions on atmospheric new particle formation, and to identify interactions of aqueous-phase and gas-phase chemistry. New particle formation was typically observed at enhanced air temperatures and enhanced solar irradiance. Volatile organic compounds were released from the salt lake surfaces, probably from a soil layer enriched in organic compounds from decomposed leaf litter, and accumulated in the chamber air. After oxidation of these organic precursor gases, the reaction products contributed to new particle formation with observed growth rates from 2.7 to 25.4nmh -1 . The presence of ferrous and ferric iron and a drop of pH values in the salt lake water just before new particle formation events indicated that organic compounds were also oxidized in the aqueous phase, affecting the new particle formation process in the atmosphere. The contribution of aqueous-phase chemistry to new particle formation is assumed, as a mixture of hundreds of oxidized organic compounds was characterized with several analytical techniques. This chemically diverse composition of the organic aerosol fraction contained sulfur- and nitrogen-containing organic compounds, and halogenated organic compounds. Coarse mode particles were analyzed using electron microscopy, energy dispersive X-ray spectroscopy and Raman spectroscopy. Ultra-high resolution mass spectrometry was applied to analyze filter samples. A targeted mass spectral analysis revealed the formation of organosulfates from monoterpene precursors and two known tracers for secondary organic aerosol formation from atmospheric oxidation of 1,8-cineole, which indicates that a complex interplay of aqueous-phase and gas-phase oxidation of monoterpenes contributes to new particle formation in the investigated salt lake environment. Copyright © 2016. Published by Elsevier B.V.

Effect of supercritical carbon dioxide decaffeination on volatile components of green teas.

PubMed

Lee, S; Park, M K; Kim, K H; Kim, Y-S

2007-09-01

Volatile components in regular and decaffeinated green teas were isolated by simultaneous steam distillation and solvent extraction (SDE), and then analyzed by GC-MS. A total of 41 compounds, including 8 alcohols, 15 terpene-type compounds, 10 carbonyls, 4 N-containing compounds, and 4 miscellaneous compounds, were found in regular and decaffeinated green teas. Among them, linalool and phenylacetaldehyde were quantitatively dominant in both regular and decaffeinated green teas. By a decaffeination process using supercritical carbon dioxide, most volatile components decreased. The more caffeine was removed, the more volatile components were reduced in green teas. In particular, relatively nonpolar components such as terpene-type compounds gradually decreased according to the decaffeination process. Aroma-active compounds in regular and decaffeinated green teas were also determined and compared by aroma extract dilution analysis (AEDA). Most greenish and floral flavor compounds such as hexanal, (E)-2-hexenal, and some unknown compounds disappeared or decreased after the decaffeination process.

Analysis of volatile organic compounds in pleural effusions by headspace solid-phase microextraction coupled with cryotrap gas chromatography and mass spectrometry.

PubMed

Huang, Zhongping; Zhang, Jie; Zhang, Peipei; Wang, Hong; Pan, Zaifa; Wang, Lili

2016-07-01

Headspace solid-phase microextraction coupled with cryotrap gas chromatography and mass spectrometry was applied to the analysis of volatile organic compounds in pleural effusions. The highly volatile organic compounds were separated successfully with high sensitivity by the employment of a cryotrap device, with the construction of a cold column head by freezing a segment of metal capillary with liquid nitrogen. A total of 76 volatile organic compounds were identified in 50 pleural effusion samples (20 malignant effusions and 30 benign effusions). Among them, 34 more volatile organic compounds were detected with the retention time less than 8 min, by comparing with the normal headspace solid-phase microextraction coupled with gas chromatography and mass spectrometry method. Furthermore, 24 volatile organic compounds with high occurrence frequency in pleural effusion samples, 18 of which with the retention time less than 8 min, were selected for the comparative analysis. The results of average peak area comparison and box-plot analysis showed that except for cyclohexanone, 2-ethyl-1-hexanol, and tetramethylbenzene, which have been reported as potential cancer biomarkers, cyclohexanol, dichloromethane, ethyl acetate, n-heptane, ethylbenzene, and xylene also had differential expression between malignant and benign effusions. Therefore, the proposed approach was valuable for the comprehensive characterization of volatile organic compounds in pleural effusions. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of a sparging technique for volatile emissions from potato (Solanum tuberosum)

NASA Technical Reports Server (NTRS)

Berdis, Elizabeth; Peterson, Barbara Vieux; Yorio, Neil C.; Batten, Jennifer; Wheeler, Raymond M.

1993-01-01

Accumulation of volatile emissions from plants grown in tightly closed growth chambers may have allelopathic or phytotoxic properties. Whole air analysis of a closed chamber includes both biotic and abiotic volatile emissions. A method for characterization and quantification of biogenic emissions solely from plantlets was developed to investigate this complex mixture of volatile organic compounds. Volatile organic compounds from potato (Solanum tuberosum L. cv. Norland) were isolated, separated and identified using an in-line configuration consisting of a purge and trap concentrator with sparging vessels coupled to a GC/MS system. Analyses identified plant volatile compounds: transcaryophyllene, alpha-humulene, thiobismethane, hexanal, cis-3-hexen-1-ol, and cis-3-hexenyl acetate.

Volatile Organic Compounds from Logwood Combustion: Emissions and Transformation under Dark and Photochemical Aging Conditions in a Smog Chamber.

PubMed

Hartikainen, Anni; Yli-Pirilä, Pasi; Tiitta, Petri; Leskinen, Ari; Kortelainen, Miika; Orasche, Jürgen; Schnelle-Kreis, Jürgen; Lehtinen, Kari E J; Zimmermann, Ralf; Jokiniemi, Jorma; Sippula, Olli

2018-04-17

Residential wood combustion (RWC) emits high amounts of volatile organic compounds (VOCs) into ambient air, leading to formation of secondary organic aerosol (SOA), and various health and climate effects. In this study, the emission factors of VOCs from a logwood-fired modern masonry heater were measured using a Proton-Transfer-Reactor Time-of-Flight Mass Spectrometer. Next, the VOCs were aged in a 29 m 3 Teflon chamber equipped with UV black lights, where dark and photochemical atmospheric conditions were simulated. The main constituents of the VOC emissions were carbonyls and aromatic compounds, which accounted for 50%-52% and 30%-46% of the detected VOC emission, respectively. Emissions were highly susceptible to different combustion conditions, which caused a 2.4-fold variation in emission factors. The overall VOC concentrations declined considerably during both dark and photochemical aging, with simultaneous increase in particulate organic aerosol mass. Especially furanoic and phenolic compounds decreased, and they are suggested to be the major precursors of RWC-originated SOA in all aging conditions. On the other hand, dark aging produced relatively high amounts of nitrogen-containing organic compounds in both gas and particulate phase, while photochemical aging increased especially the concentrations of certain gaseous carbonyls, particularly acid anhydrides.

A GC-MS method for the detection of toluene and ethylbenzene in volatile substance abuse.

PubMed

El-Haj, B M; Al-Amri, A M; Hassan, M H; Bin-Khadem, R K; Al-Hadi, A A

2000-09-01

The interference of some substances with the gas chromatography-flame ionization detection and gas chromatography-Fourier transform infrared detection of toluene and ethylbenzene in volatile substance abuse poses problems. A gas chromatography-mass spectrometry (GC-MS) method that will overcome such interference has been developed for the detection of toluene and/or ethylbenzene in the headspace of preparations and products containing these substances and in the headspace of blood samples in the cases of volatile substance abuse. The method is based on converting toluene to benzoic acid via the formation of benzotrichloride. The latter compound was obtained upon the reaction of toluene with chlorine gas under direct sunlight conditions. In the presence of water, benzotrichloride was converted to benzoic acid. Ethylbenzene was converted to benzoic acid and two phenylethanols via the formation of side chain chloro-substituted phenylethanes followed by reaction with water. The chloro-substituted phenylethanes were obtained by the reaction of ethylbenzene with chlorine under direct sunlight conditions. The benzoic acid resulting from toluene and/or ethylbenzene and the two phenylethanols resulting from ethylbenzene were detected by GC-MS as their trimethylsilyl (TMS) derivatives. For the method to be viable for the detection of volatile substance abuse, the chlorination reactions were effected in the gaseous state.

SEMI-VOLATILE ORGANIC ACIDS AND OTHER POLAR COMPOUNDS COLLECTED IN NEW YORK CITY IN RESPONSE TO THE EVENTS OF 9/11

EPA Science Inventory

Concentrations of over 25 polar semi-volatile and non-volatile organic compounds were measured in Lower Manhattan, New York using a high capacity Integrated Organic Gas and Particle sampler, after the initial destruction of the World Trade Center. The polar organic compounds in...

78 FR 53029 - Air Quality: Revision to Definition of Volatile Organic Compounds-Exclusion of trans

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-28

... Air Quality: Revision to Definition of Volatile Organic Compounds--Exclusion of trans 1-chloro-3,3,3.... SUMMARY: The EPA is taking final action to revise the regulatory definition of volatile organic compounds..., June 16, 2010), and as a solvent for metals, electronics, and precision cleaning and in adhesives...

Volatile compounds in samples of cork and also produced by selected fungi.

PubMed

Barreto, M C; Vilas Boas, L; Carneiro, L C; San Romão, M V

2011-06-22

The production of volatile compounds by microbial communities of cork samples taken during the cork manufacturing process was investigated. The majority of volatiles were found in samples collected at two stages: resting after the first boiling and nontreated cork disks. Volatile profiles produced by microbiota in both stages are similar. The releasable volatile compounds and 2,4,6-trichloroanisole (TCA) produced in cork-based culture medium by five isolated fungal species in pure and mixed cultures were also analyzed by gas chromatography coupled with mass spectrometry (GC-MS).The results showed that 1-octen-3-ol and esters of fatty acids (medium chain length C8-C20) were the main volatile compounds produced by either pure fungal species or their mixture. Apparently, Penicillium glabrum is the main contributor to the overall volatile composition observed in the mixed culture. The production of releasable TCA on cork cannot be attributed to any of the assayed fungal isolates.

Characterisation of volatile profiles in 50 native Peruvian chili pepper using solid phase microextraction-gas chromatography mass spectrometry (SPME-GCMS).

PubMed

Patel, Kirti; Ruiz, Candy; Calderon, Rosa; Marcelo, Mavel; Rojas, Rosario

2016-11-01

The volatiles were characterised by headspace solid phase micro extraction (HS-SPME), gas chromatography mass spectrometry (GC-FID/MS). A total of 127 compounds were identified with terpenes (including mono terpenes and sesquiterpenes - a total of 45 compounds), esters (31 compounds) and hydrocarbons (20 compounds) were the predominant volatile compounds. Principal component analysis (PCA) of the volatile compounds yielded 2 significant PC's, which together accounted for 90.3% of the total variance in the data set and the scatter plot generated between PC1 and PC2 successfully segregated the 50 chili pepper samples into 7 groups. Clusters of hydrocarbons, esters, terpenes, aldehyde and ketones formed the major determinants of the difference. Copyright © 2016 Elsevier Ltd. All rights reserved.

Indoor volatiles of primary school classrooms in Tapachula, Chiapas, Mexico, are attractants to Aedes aegypti females.

PubMed

Torres Estrada, José Luis; Ríos Delgado, Silvany Mayoly; Takken, Willem

2013-09-01

We determined the behavioral response of Aedes aegypti females to volatile compounds collected in indoor primary school classrooms. Volatiles were collected from classrooms from 0800 through 1030 h and 1130 through 1400 h in urban and rural schools in Tapachula, Chiapas, Mexico. Female responses to volatiles were assessed in a Y-tube olfactometer. Chemical compounds were identified using gas chromatography-mass spectrometer analysis. Volatiles from both schools were attractive when compared against their control. When such volatiles were compared, those from the rural school were more attractive than the ones from the urban school. Chromatographic profiles were similar between schools; however, the rural school showed more compounds. Attraction of Ae. aegypti females toward volatiles of primary school classrooms might increase dengue transmission probabilities in those sites.

An investigation on the chemotactic responses of different entomopathogenic nematode strains to mechanically damaged maize root volatile compounds.

PubMed

Laznik, Z; Trdan, S

2013-07-01

Entomopathogenic nematodes (EPNs) respond to a variety of stimuli when foraging. In a laboratory investigation, we tested the chemotactic responses of 8 EPN strains (Steinernema and Heterorhabditis) to three mechanically damaged maize root compounds (linalool, α-caryophyllene and β-caryophyllene). We hypothesized that the EPN directional response to the tested volatile compounds would vary among the species and volatile compound and may be related to foraging strategies. The nematodes with an intermediate foraging strategy (Steinernema feltiae) proved to be less active in their movement toward volatile compounds in a comparison with the ambushers (Steinernema carpocapsae) and cruisers (Steinernema kraussei and Heterorhabditis bacteriophora); β-caryophyllene was found to be the most attractive substance in our experiment. The results of our investigation showed that the cruisers were more attracted to β-caryophyllene than the ambushers and intermediates. The foraging strategy did not affect the movement of the IJs toward the other tested volatile compounds or the control. Our results suggest that the response to different volatile cues is more a strain-specific characteristic than a different host-searching strategy. Only S. carpocapsae strain B49 displayed an attraction to linalool, whereas S. kraussei showed a retarded reaction to β-caryophyllene and α-caryophyllene in our experiment. The EPN strains showed only a weak attraction to α-caryophyllene, suggesting that this volatile compound could not have an important role in the orientation of IJs to the damaged roots of maize plants. These results expand our knowledge of volatile compounds as the cues that may be used by EPNs for finding hosts or other aspects of navigation in the soil. Copyright © 2013 Elsevier Inc. All rights reserved.

The aroma volatile repertoire in strawberry fruit: a review.

PubMed

Yan, Jia-Wei; Ban, Zhao-Jun; Lu, Hong-Yan; Li, Dong; Poverenov, Elena; Li, Li; Luo, Zi-Sheng

2018-03-30

Aroma significantly contributes to flavor, which directly affects commercial quality of strawberry. Strawberry aroma is complex as many kinds of volatile compounds are found in strawberries. In this review, we describe the current knowledge of constituents and biosynthesis of strawberry volatile compounds, and the effect of postharvest treatments on aroma profiles. The characteristic strawberry volatile compounds consist of furanones, such as 2,5-dimethyl-4-hydroxy-3(2H)-furanone and 4-methoxy-2,5-dimethyl-3(2H)-furanone; esters including ethyl butanoate, ethyl hexanoate, methyl butanoate, and methyl hexanoate; sulfur compounds such as methanethiol, and terpenoids including linalool and nerolidol. As for postharvest treatment, the present review discusses the overview of aroma volatiles in response to temperature, atmosphere, and exogenous hormone as well as other treatments including ozone, edible coating and ultraviolet radiation. In addition, the future prospects for strawberry volatile biosynthesis and metabolism are presented. This article is protected by copyright. All rights reserved.

Aerosol chemical vapor deposition of metal oxide films

DOEpatents

Ott, K.C.; Kodas, T.T.

1994-01-11

A process of preparing a film of a multicomponent metal oxide including: forming an aerosol from a solution comprised of a suitable solvent and at least two precursor compounds capable of volatilizing at temperatures lower than the decomposition temperature of said precursor compounds; passing said aerosol in combination with a suitable oxygen-containing carrier gas into a heated zone, said heated zone having a temperature sufficient to evaporate the solvent and volatilize said precursor compounds; and passing said volatilized precursor compounds against the surface of a substrate, said substrate having a sufficient temperature to decompose said volatilized precursor compounds whereby metal atoms contained within said volatilized precursor compounds are deposited as a metal oxide film upon the substrate is disclosed. In addition, a coated article comprising a multicomponent metal oxide film conforming to the surface of a substrate selected from the group consisting of silicon, magnesium oxide, yttrium-stabilized zirconium oxide, sapphire, or lanthanum gallate, said multicomponent metal oxide film characterized as having a substantially uniform thickness upon said substrate.

Recovery of several volatile organic compounds from simulated water samples: Effect of transport and storage

USGS Publications Warehouse

Friedman, L.C.; Schroder, L.J.; Brooks, M.G.

1986-01-01

Solutions containing volatile organic compounds were prepared in organic-free water and 2% methanol and submitted to two U.S. Geological Survey laboratories. Data from the determination of volatile compounds in these samples were compared to analytical data for the same volatile compounds that had been kept in solutions 100 times more concentrated until immediately before analysis; there was no statistically significant difference in the analytical recoveries. Addition of 2% methanol to the storage containers hindered the recovery of bromomethane and vinyl chloride. Methanol addition did not enhance sample stability. Further, there was no statistically significant difference in results from the two laboratories, and the recovery efficiency was more than 80% in more than half of the determinations made. In a subsequent study, six of eight volatile compounds showed no significant loss of recovery after 34 days.

A comparison of solid-phase microextraction (SPME) with simultaneous distillation-extraction (SDE) for the analysis of volatile compounds in heated beef and sheep fats.

PubMed

Watkins, P J; Rose, G; Warner, R D; Dunshea, F R; Pethick, D W

2012-06-01

A comparison has been made on the application of SPME and SDE for the extraction of volatile compounds from heated beef and sheep fats with separation and measurement by gas chromatography-mass spectrometry. As far as we know, this report represents the first time that such a comparison has been made for the measurement of volatile compounds in heated sheep fat. Approximately 100 compounds (in relatively high abundance) were characterised in the volatile profiles of heated beef and sheep fats using both techniques. Differences were observed in the volatile profiles obtained from each technique, independent of compound class. Rather than rate one technique as superior to another, the techniques can be regarded as complementary to each other. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Metabolomic approach for determination of key volatile compounds related to beef flavor in glutathione-Maillard reaction products.

PubMed

Lee, Sang Mi; Kwon, Goo Young; Kim, Kwang-Ok; Kim, Young-Suk

2011-10-10

The non-targeted analysis, combining gas chromatography coupled with time-of-flight mass spectrometry (GC-TOF/MS) and sensory evaluation, was applied to investigate the relationship between volatile compounds and the sensory attributes of glutathione-Maillard reaction products (GSH-MRPs) prepared under different reaction conditions. Volatile compounds in GSH-MRPs correlating to the sensory attributes were determined using partial least-squares (PLS) regression. Volatile compounds such as 2-methylfuran-3-thiol, 3-sulfanylpentan-2-one, furan-2-ylmethanethiol, 2-propylpyrazine, 1-furan-2-ylpropan-2-one, 1H-pyrrole, 2-methylthiophene, and 2-(furan-2-ylmethyldisulfanylmethyl)furan could be identified as possible key contributors to the beef-related attributes of GSH-MRPs. In this study, we demonstrated that the unbiased non-targeted analysis based on metabolomic approach allows the identification of key volatile compounds related to beef flavor in GSH-MRPs. Copyright © 2011 Elsevier B.V. All rights reserved.

A large source of low-volatility secondary organic aerosol

NASA Astrophysics Data System (ADS)

Ehn, Mikael; Thornton, Joel A.; Kleist, Einhard; Sipilä, Mikko; Junninen, Heikki; Pullinen, Iida; Springer, Monika; Rubach, Florian; Tillmann, Ralf; Lee, Ben; Lopez-Hilfiker, Felipe; Andres, Stefanie; Acir, Ismail-Hakki; Rissanen, Matti; Jokinen, Tuija; Schobesberger, Siegfried; Kangasluoma, Juha; Kontkanen, Jenni; Nieminen, Tuomo; Kurtén, Theo; Nielsen, Lasse B.; Jørgensen, Solvejg; Kjaergaard, Henrik G.; Canagaratna, Manjula; Maso, Miikka Dal; Berndt, Torsten; Petäjä, Tuukka; Wahner, Andreas; Kerminen, Veli-Matti; Kulmala, Markku; Worsnop, Douglas R.; Wildt, Jürgen; Mentel, Thomas F.

2014-02-01

Forests emit large quantities of volatile organic compounds (VOCs) to the atmosphere. Their condensable oxidation products can form secondary organic aerosol, a significant and ubiquitous component of atmospheric aerosol, which is known to affect the Earth's radiation balance by scattering solar radiation and by acting as cloud condensation nuclei. The quantitative assessment of such climate effects remains hampered by a number of factors, including an incomplete understanding of how biogenic VOCs contribute to the formation of atmospheric secondary organic aerosol. The growth of newly formed particles from sizes of less than three nanometres up to the sizes of cloud condensation nuclei (about one hundred nanometres) in many continental ecosystems requires abundant, essentially non-volatile organic vapours, but the sources and compositions of such vapours remain unknown. Here we investigate the oxidation of VOCs, in particular the terpene α-pinene, under atmospherically relevant conditions in chamber experiments. We find that a direct pathway leads from several biogenic VOCs, such as monoterpenes, to the formation of large amounts of extremely low-volatility vapours. These vapours form at significant mass yield in the gas phase and condense irreversibly onto aerosol surfaces to produce secondary organic aerosol, helping to explain the discrepancy between the observed atmospheric burden of secondary organic aerosol and that reported by many model studies. We further demonstrate how these low-volatility vapours can enhance, or even dominate, the formation and growth of aerosol particles over forested regions, providing a missing link between biogenic VOCs and their conversion to aerosol particles. Our findings could help to improve assessments of biosphere-aerosol-climate feedback mechanisms, and the air quality and climate effects of biogenic emissions generally.

A large source of low-volatility secondary organic aerosol.

PubMed

Ehn, Mikael; Thornton, Joel A; Kleist, Einhard; Sipilä, Mikko; Junninen, Heikki; Pullinen, Iida; Springer, Monika; Rubach, Florian; Tillmann, Ralf; Lee, Ben; Lopez-Hilfiker, Felipe; Andres, Stefanie; Acir, Ismail-Hakki; Rissanen, Matti; Jokinen, Tuija; Schobesberger, Siegfried; Kangasluoma, Juha; Kontkanen, Jenni; Nieminen, Tuomo; Kurtén, Theo; Nielsen, Lasse B; Jørgensen, Solvejg; Kjaergaard, Henrik G; Canagaratna, Manjula; Maso, Miikka Dal; Berndt, Torsten; Petäjä, Tuukka; Wahner, Andreas; Kerminen, Veli-Matti; Kulmala, Markku; Worsnop, Douglas R; Wildt, Jürgen; Mentel, Thomas F

2014-02-27

Forests emit large quantities of volatile organic compounds (VOCs) to the atmosphere. Their condensable oxidation products can form secondary organic aerosol, a significant and ubiquitous component of atmospheric aerosol, which is known to affect the Earth's radiation balance by scattering solar radiation and by acting as cloud condensation nuclei. The quantitative assessment of such climate effects remains hampered by a number of factors, including an incomplete understanding of how biogenic VOCs contribute to the formation of atmospheric secondary organic aerosol. The growth of newly formed particles from sizes of less than three nanometres up to the sizes of cloud condensation nuclei (about one hundred nanometres) in many continental ecosystems requires abundant, essentially non-volatile organic vapours, but the sources and compositions of such vapours remain unknown. Here we investigate the oxidation of VOCs, in particular the terpene α-pinene, under atmospherically relevant conditions in chamber experiments. We find that a direct pathway leads from several biogenic VOCs, such as monoterpenes, to the formation of large amounts of extremely low-volatility vapours. These vapours form at significant mass yield in the gas phase and condense irreversibly onto aerosol surfaces to produce secondary organic aerosol, helping to explain the discrepancy between the observed atmospheric burden of secondary organic aerosol and that reported by many model studies. We further demonstrate how these low-volatility vapours can enhance, or even dominate, the formation and growth of aerosol particles over forested regions, providing a missing link between biogenic VOCs and their conversion to aerosol particles. Our findings could help to improve assessments of biosphere-aerosol-climate feedback mechanisms, and the air quality and climate effects of biogenic emissions generally.

Leaf Volatile Compounds and Associated Gene Expression during Short-Term Nitrogen Deficient Treatments in Cucumis Seedlings

PubMed Central

Deng, Jie; Yu, Hong-Jun; Li, Yun-Yun; Zhang, Xiao-Meng; Liu, Peng; Li, Qiang; Jiang, Wei-Jie

2016-01-01

Nitrogen (N) is an important macronutrient for plant growth and development, but the regulatory mechanism of volatile compounds in response to N deficiency is not well understood, especially in cucumber, which consumes excessive N during growth. In this study, the major volatile compounds from cucumber leaves subjected to N deficiency were analyzed by GC-MS. A total of 24 volatile components were identified including 15 aldehydes, two ketones, two alkenes, and five other volatile compounds in 9930 leaves. Principal component analysis using volatile compounds from cucumber leaves provided good separation between N-sufficient and N-deficient treatments. The main volatiles in cucumber leaves were found to be C6 and C9 aldehydes, especially (E)-2-hexanal and (E,Z)-2,6-nonadienal. (E)-2-hexanal belonged to the C6 aldehyde and was the most abundant compound, whereas (E,Z)-2,6-nonadienal was the chief component of C9 aldehydes. During N-deficient treatment, short-chain volatile content was significantly improved at 5 day, other volatiles displayed significant reduction or no significantly changes in all sampling points. Improvement of short-chain volatiles was confirmed in the six other inbred lines at 5 day after N-deficient treatments. The expression analysis of 12 cucumber LOX genes and two HPL genes revealed that CsLOX19, CsLOX20, and CsLOX22 had common up-regulated expression patterns in response to N-deficient stress in most inbred lines; meanwhile, most sample points of CsHPL1 also had significant up-regulated expression patterns. This research focused on the relationship between volatiles in cucumber and different nitrogen environments to provide valuable insight into the effect of cultivation and management of the quality of cucumber and contributes to further research on volatile metabolism in cucumber. PMID:27827841

Secondary organic aerosol formation from isoprene photo-oxidation during cloud condensation-evaporation cycles (CUMULUS project)

NASA Astrophysics Data System (ADS)

Brégonzio-Rozier, Lola; Siekmann, Frank; Giorio, Chiara; Temime-Roussel, Brice; Pangui, Edouard; Morales, Sébastien; Gratien, Aline; Ravier, Sylvain; Monod, Anne; Doussin, Jean-Francois

2014-05-01

It is acknowledged that atmospheric photo-oxidation of Volatile Organic Compounds (VOC) leads to the formation of less volatile oxidized species. These compounds can undergo gas-to-particle conversion, leading to the formation of Secondary Organic Aerosols (SOA) in the atmosphere. Nevertheless, some of these oxidized species are water soluble and could also partition into cloud droplets. Higher molecular weight and less volatile compounds could be produced in the aqueous phase and remain in the particle phase after water evaporation (Ervens et al., 2011). The aim of the present work is to study SOA formation in the presence of cloud droplets during isoprene photo-oxidation. To this end, an original multiphase approach in a simulation chamber was set up in order to investigate the chemistry occurring in the gaseous, particulate and aqueous phases, and the exchange between these phases. Experiments were performed, within the CUMULUS project (CloUd MULtiphase chemistry of organic compoUndS in the troposphere), in the CESAM chamber (Wang et al., 2011). This chamber was designed to investigate multiphase processes under realistic actinic flux, and accurate control of both temperature and relative humidity. A specific protocol was set up to produce cloud events in the simulation chamber exhibiting a significant lifetime in the presence of light (10-12 minutes). By using this protocol, many clouds could be generated in a single experiment. In each experiment, around 800 ppb of isoprene was injected in the chamber together with HONO under dry conditions before irradiation. A Fourier Transform Infrared Spectrometer (FTIR), a Proton Transfer Reaction Mass Spectrometer (PTR-TOF-MS) and NOx and O3 analyzers were used to analyze gas-phase composition. Dried SOA size distributions and total concentrations were measured by a Scanning Mobility Particle Sizer (SMPS). An Aerodyne High Resolution Time-Of-Flight Aerosol Mass Spectrometer (HR-TOF-AMS) was also used to investigate aerosol composition. Cloud droplets size distributions were measured by a white light Optical Particle Counter (OPC). In all experiments, the dissolution of gaseous oxidation products into aqueous phase and SOA production have been observed during isoprene photo-oxidation in the presence of a cloud event. The overall results in additional SOA mass production and the dynamic of gaseous oxidation products and SOA mass concentrations will be presented. Ervens, B. et al. (2011). Atmospheric Chemistry and Physics 11(21): 11069-11102. Wang, J. et al. (2011). Atmospheric Measurement Techniques 4(11): 2465-2494.

Effect of inorganic salts on the volatility of organic acids.

PubMed

Häkkinen, Silja A K; McNeill, V Faye; Riipinen, Ilona

2014-12-02

Particulate phase reactions between organic and inorganic compounds may significantly alter aerosol chemical properties, for example, by suppressing particle volatility. Here, chemical processing upon drying of aerosols comprised of organic (acetic, oxalic, succinic, or citric) acid/monovalent inorganic salt mixtures was assessed by measuring the evaporation of the organic acid molecules from the mixture using a novel approach combining a chemical ionization mass spectrometer coupled with a heated flow tube inlet (TPD-CIMS) with kinetic model calculations. For reference, the volatility, i.e. saturation vapor pressure and vaporization enthalpy, of the pure succinic and oxalic acids was also determined and found to be in agreement with previous literature. Comparison between the kinetic model and experimental data suggests significant particle phase processing forming low-volatility material such as organic salts. The results were similar for both ammonium sulfate and sodium chloride mixtures, and relatively more processing was observed with low initial aerosol organic molar fractions. The magnitude of low-volatility organic material formation at an atmospherically relevant pH range indicates that the observed phenomenon is not only significant in laboratory conditions but is also of direct atmospheric relevance.

Effect of freeze-drying and oven-drying on volatiles and phenolics composition of grape skin.

PubMed

de Torres, C; Díaz-Maroto, M C; Hermosín-Gutiérrez, I; Pérez-Coello, M S

2010-02-15

Grape skins are the part of the fruit with the highest amount of volatile and polyphenolic compounds. Volatile compounds give the fruit and other grape derivatives their flavour. Polyphenolic compounds are responsible for the colour of the fruit, juice and wine, and also act as very important natural antioxidant compounds. Dehydration is a method used to prevent the damage of these compounds over time. Nevertheless, in the case of volatile compounds, removing water can cause compound degradation or the evaporation of such compounds. This work studied two drying methods, freeze-drying and oven-drying, at 60 degrees C, as skin preservation methods. The skins from two grape varieties, Carménère and Cabernet Sauvignon, were dried. Many volatile compounds, which are of interest in the aroma profile, were identified in both varieties as terpenes (linalool, etc.), sesquiterpenes (farnesol), norisoprenoids (vitispirane, etc.), C(6) alcohols (1-hexanol, etc.), etc., and their amount decreased significantly with the oven-drying method, in contrast to the freeze-drying method. Both phenolic compounds, anthocyanins and flavonols, were identified in fresh and dehydrated samples, thus resulting in the freeze-drying method being less aggressive than oven-drying methods. Copyright 2009 Elsevier B.V. All rights reserved.

Germination of penicillium paneum Conidia is regulated by 1-octen-3-ol, a volatile self-inhibitor.

PubMed

Chitarra, Gilma S; Abee, Tjakko; Rombouts, Frank M; Posthumus, Maarten A; Dijksterhuis, Jan

2004-05-01

Penicillium paneum is an important contaminant of cereal grains which is able to grow at low temperature, low pH, high levels of carbon dioxide, and under acid conditions. P. paneum produces mycotoxins, which may be harmful to animals and humans. We found that conidia in dense suspensions showed poor germination, suggesting the presence of a self-inhibitor. A volatile compound(s) produced by these high-density conditions also inhibited mycelial growth of different species of fungi belonging to a variety of genera, suggesting a broad action range. The heat-stable compound was isolated by successive centrifugation of the supernatant obtained from spore suspensions with a density of 10(9) conidia ml(-1). By using static headspace analyses, two major peaks were distinguished, with the highest production of these metabolites after 22 h of incubation at 25 degrees C and shaking at 140 rpm. Gas chromatography coupled with mass spectra analysis revealed the compounds to be 3-octanone and 1-octen-3-ol. Notably, only the latter compound appeared to block the germination process at different developmental stages of the conidia (swelling and germ tube formation). In this study, 1-octen-3-ol influenced different developmental processes during the P. paneum life cycle, including induction of microcycle conidiation and inhibition of spore germination. Therefore, the compound can be considered a fungal hormone during fungal development.

Germination of Penicillium paneum Conidia Is Regulated by 1-Octen-3-ol, a Volatile Self-Inhibitor

PubMed Central

Chitarra, Gilma S.; Abee, Tjakko; Rombouts, Frank M.; Posthumus, Maarten A.; Dijksterhuis, Jan

2004-01-01

Penicillium paneum is an important contaminant of cereal grains which is able to grow at low temperature, low pH, high levels of carbon dioxide, and under acid conditions. P. paneum produces mycotoxins, which may be harmful to animals and humans. We found that conidia in dense suspensions showed poor germination, suggesting the presence of a self-inhibitor. A volatile compound(s) produced by these high-density conditions also inhibited mycelial growth of different species of fungi belonging to a variety of genera, suggesting a broad action range. The heat-stable compound was isolated by successive centrifugation of the supernatant obtained from spore suspensions with a density of 109 conidia ml−1. By using static headspace analyses, two major peaks were distinguished, with the highest production of these metabolites after 22 h of incubation at 25°C and shaking at 140 rpm. Gas chromatography coupled with mass spectra analysis revealed the compounds to be 3-octanone and 1-octen-3-ol. Notably, only the latter compound appeared to block the germination process at different developmental stages of the conidia (swelling and germ tube formation). In this study, 1-octen-3-ol influenced different developmental processes during the P. paneum life cycle, including induction of microcycle conidiation and inhibition of spore germination. Therefore, the compound can be considered a fungal hormone during fungal development. PMID:15128538

Edible Oil Barriers for Treatment of Chlorinated Solvent Contaminated Groundwater

DTIC Science & Technology

2009-07-01

CF Chloroform Cl# Chlorine Number CO Carbon Monoxide CT Carbon Tetrachloride CVOC Chlorinated Volatile Organic Compound 1,2-DCA 1,2...As Safe HCl Hydrochloric Acid HRC® Hydrogen Release Compound IDW Investigation-Derived Waste ISCO In Situ Chemical Oxidation LEL Lower...Total Organic Carbon VC Vinyl Chloride VFA Volatile Fatty Acid VOC Volatile Organic Compound ZVI Zero Valent Iron viii ACKNOWLEDGEMENTS

Relationship between sensory attributes and volatile compounds of polish dry-cured loin

PubMed Central

Górska, Ewa; Nowicka, Katarzyna; Jaworska, Danuta; Przybylski, Wiesław; Tambor, Krzysztof

2017-01-01

Objective The aim of this work was to determine the relationship between objective sensory descriptors and volatile flavour compound composition of Polish traditional dry-cured loin. Methods The volatile compounds were investigated by using solid phase microextraction (SPME) and gas chromatography–mass spectrometry (GC–MS). For sensory assessment, the quantitative descriptive analysis (QDA) method was used. Results A total of 50 volatile compounds were found and assigned to 17 chemical families. Most of the detected volatile compounds derived from smoking, lipid oxidative reactions and seasoning (46.8%, 21.7%, and 18.9%, respectively). The dominant compounds were: aromatic hydrocarbon (toluene); alkanes (hexane, heptane, and 2,2,4-trimethylpentane); aldehyde (hexanal); alcohol (2-furanmethanol); ketone (3-hydroxy-2-butanone); phenol (guaiacol); and terpenes (eucalyptol, cymene, γ-terpinen, and limonene). Correlation analysis showed that some compounds derived from smoking were positively correlated with the intensity of cured meat odour and flavour and negatively with the intensity of dried meat odour and flavour, while terpenes were strongly correlated with odour and flavour of added spices. Conclusion The analysed dry-cured loins were characterized by specific and unique sensory profile. Odour and flavour of studied loins was mainly determined by volatile compounds originating from smoking, seasoning and lipid oxidation. Obtained results suggest that smoking process is a crucial stage during Polish traditional dry-cured loins production. PMID:27456422

Volatile Metabolites

PubMed Central

Rowan, Daryl D.

2011-01-01

Volatile organic compounds (volatiles) comprise a chemically diverse class of low molecular weight organic compounds having an appreciable vapor pressure under ambient conditions. Volatiles produced by plants attract pollinators and seed dispersers, and provide defense against pests and pathogens. For insects, volatiles may act as pheromones directing social behavior or as cues for finding hosts or prey. For humans, volatiles are important as flavorants and as possible disease biomarkers. The marine environment is also a major source of halogenated and sulfur-containing volatiles which participate in the global cycling of these elements. While volatile analysis commonly measures a rather restricted set of analytes, the diverse and extreme physical properties of volatiles provide unique analytical challenges. Volatiles constitute only a small proportion of the total number of metabolites produced by living organisms, however, because of their roles as signaling molecules (semiochemicals) both within and between organisms, accurately measuring and determining the roles of these compounds is crucial to an integrated understanding of living systems. This review summarizes recent developments in volatile research from a metabolomics perspective with a focus on the role of recent technical innovation in developing new areas of volatile research and expanding the range of ecological interactions which may be mediated by volatile organic metabolites. PMID:24957243

Quantifying the contribution of grape hexoses to wine volatiles by high-precision [U¹³C]-glucose tracer studies.

PubMed

Nisbet, Mark A; Tobias, Herbert J; Brenna, J Thomas; Sacks, Gavin L; Mansfield, Anna Katharine

2014-07-16

Many fermentation volatiles important to wine aroma potentially arise from yeast metabolism of hexose sugars, but assessing the relative importance of these pathways is challenging due to high endogenous hexose substrate concentrations. To overcome this problem, gas chromatography combustion isotope ratio mass spectrometry (GC-C-IRMS) was used to measure high-precision (13)C/(12)C isotope ratios of volatiles in wines produced from juices spiked with tracer levels (0.01-1 APE) of uniformly labeled [U-(13)C]-glucose. The contribution of hexose to individual volatiles was determined from the degree of (13)C enrichment. As expected, straight-chain fatty acids and their corresponding ethyl esters were derived almost exclusively from hexoses. Most fusel alcohols and their acetate esters were also majority hexose-derived, indicating the importance of anabolic pathways for their formation. Only two compounds were not derived primarily from hexoses (hexanol and isobutyric acid). This approach can be extended to other food systems or substrates for studying precursor-product relationships.

[Study on chemical constituents of volatile oil from rhizomes and leaves of Pileostegia viburnoides var. glabrescens by GC-MS].

PubMed

Zou, Ju-Ying; Chen, Sheng-Huang; Li, Qin-Wen; Chen, Han-Jun; Liu, Bei-Bei; Du, Fan

2012-04-01

To analyze the chemical constituents of volatile oil from the rhizomes and leaves of Pileostegia viburnoides var. glabrescens by GC-MS. The volatile oil was extracted from the rhizomes and leaves of Pileostegia viburnoides var. glabrescens by steam distillation. The constituents of volatile oil were identified by GC-MS technology. 37 compounds were identified from the oil of rhizomes. 36 compounds were identified from the oil of leaves. The rhizomes and leaves volatile oil had 18 compounds in common. This study is the first one to report the volatile components of Pileostegia viburnoides var. glabrescens. It can provide a scientific basis for rational use of the rhizomes and leaves of Pileostegia viburnoides var. glabrescens.

Large increases in Arctic biogenic volatile emissions are a direct effect of warming

NASA Astrophysics Data System (ADS)

Kramshøj, Magnus; Vedel-Petersen, Ida; Schollert, Michelle; Rinnan, Åsmund; Nymand, Josephine; Ro-Poulsen, Helge; Rinnan, Riikka

2016-05-01

Biogenic volatile organic compounds are reactive gases that can contribute to atmospheric aerosol formation. Their emission from vegetation is dependent on temperature and light availability. Increasing temperature, changing cloud cover and shifting composition of vegetation communities can be expected to affect emissions in the Arctic, where the ongoing climate changes are particularly severe. Here we present biogenic volatile organic compound emission data from Arctic tundra exposed to six years of experimental warming or reduced sunlight treatment in a randomized block design. By separately assessing the emission response of the whole ecosystem, plant shoots and soil in four measurements covering the growing season, we have identified that warming increased the emissions directly rather than via a change in the plant biomass and species composition. Warming caused a 260% increase in total emission rate for the ecosystem and a 90% increase in emission rates for plants, while having no effect on soil emissions. Compared to the control, reduced sunlight decreased emissions by 69% for the ecosystem, 61-65% for plants and 78% for soil. The detected strong emission response is considerably higher than observed at more southern latitudes, emphasizing the high temperature sensitivity of ecosystem processes in the changing Arctic.

Physical parameters effect on ozone-initiated formation of indoor secondary organic aerosols with emissions from cleaning products.

PubMed

Huang, Yu; Ho, Kin Fai; Ho, Steven Sai Hang; Lee, Shun Cheng; Yau, P S; Cheng, Yan

2011-09-15

The effect of air exchange rate (ACH), temperature (T), and relative humidity (RH) on the formation of indoor secondary organic aerosols (SOAs) through ozonolysis of biogenic organic compounds (BVOCs) emitted from floor cleaner was investigated in this study. The total particle count (with D(p) of 6-225 nm) was up to 1.2 × 10(3)#cm(-3) with ACH of 1.08 h(-1), and it became much more significant with ACH of 0.36 h(-1) (1.1 × 10(4)#cm(-3)). This suggests that a higher ventilation rate can effectively dilute indoor BVOCs, resulting in a less ultrafine particle formation. The total particle count increased when temperature changed from 15 to 23 °C but it decreased when the temperature further increased to 30 °C. It could be explained that high temperature restrained the condensation of formed semi-volatile compounds resulting in low yields of SOAs. When the RH was at 50% and 80%, SOA formation (1.1-1.2 × 10(4)#cm(-3)) was the more efficient compared with that at RH of 30% (5.9 × 10(3)#cm(-3)), suggesting higher RH facilitating the initial nucleation processes. Oxidation generated secondary carbonyl compounds were also quantified. Acetone was the most abundant carbonyl compound. The formation mechanisms of formaldehyde and acetone were proposed. Copyright © 2011 Elsevier B.V. All rights reserved.

Clathrate hydrate formation in amorphous cometary ice analogs in vacuo

NASA Technical Reports Server (NTRS)

Blake, David; Allamandola, Louis; Sandford, Scott; Hudgins, Doug; Freund, Friedemann

1991-01-01

Experiments conducted in clathrate hydrates with a modified electron microscope have demonstrated the possibility of such compounds' formation during the warming of vapor-deposited amorphous ices in vacuo, through rearrangements in the solid state. Subsolidus crystallization of compositionally complex amorphous ices may therefore be a general and ubiquitous process. Phase separations and microporous textures thus formed may be able to account for such anomalous cometary phenomena as the release of gas at large radial distances from the sun and the retention of volatiles to elevated temperatures.

Relationships between volatile compounds and sensory characteristics in virgin olive oil by analytical and chemometric approaches.

PubMed

Procida, Giuseppe; Cichelli, Angelo; Lagazio, Corrado; Conte, Lanfranco S

2016-01-15

The volatile fraction of virgin olive oil is characterised by low molecular weight compounds that vaporise at room temperature. In order to obtain an aroma profile similar to natural olfactory perception, the composition of the volatile compounds was determined by applying dynamic headspace gas chromatography, performed at room temperature, with a cryogenic trap directly connected to a gas chromatograph-mass spectrometer system. Samples were also evaluated according to European Union and International Olive Council official methods for sensory evaluation. In this paper, the composition of the volatile fraction of 25 extra virgin olive oils from different regions of Italy was analysed and some preliminary considerations on relationships between chemical composition of volatile fraction and sensory characteristics are reported. Forty-two compounds were identified by means of the particular analytical technique used. All the analysed samples, classified as extra virgin by the panel test, never present peaks whose magnitude is important enough in defected oils. The study was focused on the evaluation of volatile compounds responsible for the positive impact on olive odour properties ('green-fruity' and 'sweet') and olfactory perception. Chemometric evaluation of data, obtained through headspace analysis and the panel test evaluation, showed a correlation between chemical compounds and sensory properties. On the basis of the results, the positive attributes of virgin olive oil are divided into two separated groups: sweet types or green types. Sixteen volatile compounds with known positive impact on odour properties were extracted and identified. In particular, eight compounds seem correlated with sweet properties whereas the green sensation appears to be correlated with eight other different substances. The content of the compounds at six carbon atoms proves to be very important in defining positive attributes of extra virgin olive oils and sensory evaluation. © 2015 Society of Chemical Industry.

40 CFR 59.505 - How do I demonstrate compliance with the reactivity limits?

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL VOLATILE ORGANIC COMPOUND EMISSION STANDARDS FOR CONSUMER AND... Volatile Organic Compounds (VOC) in Consumer Products and Reactive Organic Compounds in Aerosol Coating...

Influence of type of muscle on volatile compounds throughout the manufacture of Celta dry-cured ham.

PubMed

Bermúdez, Roberto; Franco, Daniel; Carballo, Javier; Lorenzo, José M

2015-12-01

The effect of muscle type on volatile compounds throughout the manufacture of Celta dry-cured ham was studied. Thirty Celta ham were taken from the fresh pieces, after the end of the salting stage, after 120 days of post-salting, after the end of drying-ripening stage, and after 165 and 330 days of "bodega" step. The volatile compounds from semimembranosus (SM) and biceps femoris (BF) muscles were extracted by using headspace-solid phase microextraction (SPME) and analysed by gas chromatographic/mass spectrometry (GC/MS). Fifty-five volatile compounds were identified and quantified. The number of volatile compounds increased during the different steps of the process, reaching at 550 days of process 39 and 40 volatile compounds in SM and BF muscles, respectively. Results indicated that the most abundant chemical family in flavour at the end of the manufacturing process were esters in the two muscles studied, followed by aliphatic hydrocarbons and aldehydes. During the manufacturing process, an increase in the total amount of volatile compounds was observed, being this increase more marked in samples from BF muscle (from 550.7 to 1118.9 × 10(6) area units) than in samples from SM muscle (from 459.3 to 760.4 × 10(6) area units). Finally, muscle type displayed significant (P < 0.05) differences for four esters, two alcohols, one aldehyde, one ketone and four aliphatic hydrocarbons. © The Author(s) 2014.

Application of response surface methodology to optimise supercritical carbon dioxide extraction of volatile compounds from Crocus sativus.

PubMed

Shao, Qingsong; Huang, Yuqiu; Zhou, Aicun; Guo, Haipeng; Zhang, Ailian; Wang, Yong

2014-05-01

Crocus sativus has been used as a traditional Chinese medicine for a long time. The volatile compounds of C. sativus appear biologically active and may act as antioxidants as well as anticonvulsants, antidepressants and antitumour agents. In order to obtain the highest possible yield of essential oils from C. sativus, response surface methodology was employed to optimise the conditions of supercritical fluid carbon dioxide extraction of the volatile compounds from C. sativus. Four factorswere investigated: temperature, pressure, extraction time and carbon dioxide flow rate. Furthermore, the chemical compositions of the volatile compounds extracted by supercritical fluid extraction were compared with those obtained by hydro-distillation and Soxhlet extraction. The optimum extraction conditions were found to be: optimised temperature 44.9°C, pressure 34.9 MPa, extraction time 150.2 min and CO₂ flow rate 10.1 L h⁻¹. Under these conditions, the mean extraction yield was 10.94 g kg⁻¹. The volatile compounds extracted by supercritical fluid extraction and Soxhlet extraction contained a large amount of unsaturated fatty acids. Response surface methodology was successfully applied for supercritical fluid CO₂ extraction optimisation of the volatile compounds from C. sativus. The study showed that pressure and CO₂ flow rate had significant effect on volatile compounds yield produced by supercritical fluid extraction. This study is beneficial for the further research operating on a large scale. © 2013 Society of Chemical Industry.

Volatile compound changes during shelf life of dried Boletus edulis: comparison between SPME-GC-MS and PTR-ToF-MS analysis.

PubMed

Aprea, Eugenio; Romano, Andrea; Betta, Emanuela; Biasioli, Franco; Cappellin, Luca; Fanti, Marco; Gasperi, Flavia

2015-01-01

Drying process is commonly used to allow long time storage of valuable porcini mushrooms (Boletus edulis). Although considered a stable product dried porcini flavour changes during storage. Monitoring of volatile compounds during shelf life may help to understand the nature of the observed changes. In the present work two mass spectrometric techniques were used to monitor the evolution of volatile compounds during commercial shelf life of dried porcini. Solid phase microextraction (SPME) coupled to gas chromatography - mass spectrometry (GC-MS) allowed the identification of 66 volatile compounds, 36 of which reported for the first time, monitored during the commercial shelf life of dried porcini. Proton transfer reaction - time of flight - mass spectrometry (PTR-ToF-MS) , a direct injection mass spectrometric technique, was shown to be a fast and sensitive instrument for the general monitoring of volatile compound evolution during storage of dried porcini. Furthermore, PTR-ToF-MS grants access to compounds whose determination would otherwise require lengthy pre-concentration and/or derivatization steps such as ammonia and small volatile amines. The two techniques, both used for the first time to study dried porcini, provided detailed description of time evolution of volatile compounds during shelf life. Alcohols, aldehydes, ketones and monoterpenes diminish during the storage while carboxylic acids, pyrazines, lactones and amines increase. The storage temperature modifies the rate of the observed changes influencing the final quality of the dried porcini. We showed the advantages of both techniques, suggesting a strategy to be adopted to follow time evolution of volatile compounds in food products during shelf life, based on the identification of compounds by GC-MS and the rapid time monitoring by PTR-ToF-MS measurements in order to maximize the advantages of both techniques. Copyright © 2015 John Wiley & Sons, Ltd.

78 FR 23149 - Air Quality: Revision to Definition of Volatile Organic Compounds-Exclusion of trans 1-chloro-3,3...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-18

... contribution to tropospheric ozone formation. Because EPA received one adverse comment, we are withdrawing the... air quality standards (NAAQS) for ozone under title I of the Clean Air Act (CAA). The direct final... of preparing SIPs to attain the NAAQS for ozone under title I of the CAA. If it had become effective...

Volatile fingerprints of seeds of four species indicate the involvement of alcoholic fermentation, lipid peroxidation, and Maillard reactions in seed deterioration during ageing and desiccation stress

PubMed Central

Colville, Louise

2012-01-01

The volatile compounds released by orthodox (desiccation-tolerant) seeds during ageing can be analysed using gas chromatography–mass spectrometry (GC-MS). Comparison of three legume species (Pisum sativum, Lathyrus pratensis, and Cytisus scoparius) during artificial ageing at 60% relative humidity and 50 °C revealed variation in the seed volatile fingerprint between species, although in all species the overall volatile concentration increased with storage period, and changes could be detected prior to the onset of viability loss. The volatile compounds are proposed to derive from three main sources: alcoholic fermentation, lipid peroxidation, and Maillard reactions. Lipid peroxidation was confirmed in P. sativum seeds through analysis of malondialdehyde and 4-hydroxynonenal. Volatile production by ageing orthodox seeds was compared with that of recalcitrant (desiccation-sensitive) seeds of Quercus robur during desiccation. Many of the volatiles were common to both ageing orthodox seeds and desiccating recalcitrant seeds, with alcoholic fermentation forming the major source of volatiles. Finally, comparison was made between two methods of analysis; the first used a Tenax adsorbent to trap volatiles, whilst the second used solid phase microextraction to extract volatiles from the headspace of vials containing powdered seeds. Solid phase microextraction was found to be more sensitive, detecting a far greater number of compounds. Seed volatile analysis provides a non-invasive means of characterizing the processes involved in seed deterioration, and potentially identifying volatile marker compounds for the diagnosis of seed viability loss. PMID:23175670

Volatile Compound-Mediated Interactions between Barley and Pathogenic Fungi in the Soil

PubMed Central

Fiers, Marie; Lognay, Georges; Fauconnier, Marie-Laure; Jijakli, M. Haïssam

2013-01-01

Plants are able to interact with their environment by emitting volatile organic compounds. We investigated the volatile interactions that take place below ground between barley roots and two pathogenic fungi, Cochliobolus sativus and Fusarium culmorum. The volatile molecules emitted by each fungus, by non-infected barley roots and by barley roots infected with one of the fungi or the two of them were extracted by head-space solid phase micro extraction and analyzed by gas chromatography mass spectrometry. The effect of fungal volatiles on barley growth and the effect of barley root volatiles on fungal growth were assessed by cultivating both organisms in a shared atmosphere without any physical contact. The results show that volatile organic compounds, especially terpenes, are newly emitted during the interaction between fungi and barley roots. The volatile molecules released by non-infected barley roots did not significantly affect fungal growth, whereas the volatile molecules released by pathogenic fungi decreased the length of barley roots by 19 to 21.5% and the surface of aerial parts by 15%. The spectrum of the volatiles released by infected barley roots had no significant effect on F. culmorum growth, but decreased C. sativus growth by 13 to 17%. This paper identifies the volatile organic compounds emitted by two pathogenic fungi and shows that pathogenic fungi can modify volatile emission by infected plants. Our results open promising perspectives concerning the biological control of edaphic diseases. PMID:23818966

UV-C–Irradiated Arabidopsis and Tobacco Emit Volatiles That Trigger Genomic Instability in Neighboring Plants[W

PubMed Central

Yao, Youli; Danna, Cristian H.; Zemp, Franz J.; Titov, Viktor; Ciftci, Ozan Nazim; Przybylski, Roman; Ausubel, Frederick M.; Kovalchuk, Igor

2011-01-01

We have previously shown that local exposure of plants to stress results in a systemic increase in genome instability. Here, we show that UV-C–irradiated plants produce a volatile signal that triggers an increase in genome instability in neighboring nonirradiated Arabidopsis thaliana plants. This volatile signal is interspecific, as UV-C–irradiated Arabidopsis plants transmit genome destabilization to naive tobacco (Nicotiana tabacum) plants and vice versa. We report that plants exposed to the volatile hormones methyl salicylate (MeSA) or methyl jasmonate (MeJA) exhibit a similar level of genome destabilization as UV-C–irradiated plants. We also found that irradiated Arabidopsis plants produce MeSA and MeJA. The analysis of mutants impaired in the synthesis and/or response to salicylic acid (SA) and/or jasmonic acid showed that at least one other volatile compound besides MeSA and MeJA can communicate interplant genome instability. The NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 (npr1) mutant, defective in SA signaling, is impaired in both the production and the perception of the volatile signals, demonstrating a key role for NPR1 as a central regulator of genome stability. Finally, various forms of stress resulting in the formation of necrotic lesions also generate a volatile signal that leads to genomic instability. PMID:22028460

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lucachick, Glenn; Curran, Scott; Storey, John Morse

Our work explores the volatility of particles produced from two diesel low temperature combustion (LTC) modes proposed for high-efficiency compression ignition engines. It also explores mechanisms of particulate formation and growth upon dilution in the near-tailpipe environment. Moreover, the number distribution of exhaust particles from low- and mid-load dual-fuel reactivity controlled compression ignition (RCCI) and single-fuel premixed charge compression ignition (PPCI) modes were experimentally studied over a gradient of dilution temperature. Particle volatility of select particle diameters was investigated using volatility tandem differential mobility analysis (V-TDMA). Evaporation rates for exhaust particles were compared with V-TDMA results for candidate pure n-alkanesmore » to identify species with similar volatility characteristics. The results show that LTC particles are mostly comprised of material with volatility similar to engine oil alkanes. V-TDMA results were used as inputs to an aerosol condensation and evaporation model to support the finding that smaller particles in the distribution are comprised of lower volatility material than large particles under primary dilution conditions. Although the results show that saturation levels are high enough to drive condensation of alkanes onto existing particles under the dilution conditions investigated, they are not high We conclude that observed particles from LTC operation must grow from low concentrations of highly non-volatile compounds present in the exhaust.« less

Characterization of the Key Aroma Compounds in Proso Millet Wine Using Headspace Solid-Phase Microextraction and Gas Chromatography-Mass Spectrometry.

PubMed

Liu, Jingke; Zhao, Wei; Li, Shaohui; Zhang, Aixia; Zhang, Yuzong; Liu, Songyan

2018-02-20

The volatile compounds in proso millet wine were extracted by headspace solid-phase microextraction (85 μm polyacrylate (PA), 100 μm polydimethylsiloxane (PDMS), 75 μm Carboxen (CAR)/PDMS, and 50/30 μm divinylbenzene (DVB)/CAR/PDMS fibers), and analyzed using gas chromatography-mass spectrometry; the odor characteristics and intensities were analyzed by the odor activity value (OAV). Different sample preparation factors were used to optimize this method: sample amount, extraction time, extraction temperature, and content of NaCl. A total of 64 volatile compounds were identified from the wine sample, including 14 esters, seven alcohols, five aldehydes, five ketones, 12 benzene derivatives, 12 hydrocarbons, two terpenes, three phenols, two acids, and two heterocycles. Ethyl benzeneacetate, phenylethyl alcohol, and benzaldehyde were the main volatile compounds found in the samples. According to their OAVs, 14 volatile compounds were determined to be odor-active compounds (OAV > 1), and benzaldehyde, benzeneacetaldehyde, 1-methyl-naphthalene, 2-methyl-naphthalene, and biphenyl were the prominent odor-active compounds (OAV > 50), having a high OAV. Principal component analysis (PCA) showed the difference of distribution of the 64 volatile compounds and 14 odor-active compounds with four solid-phase microextraction (SPME) fibers.

Why Do Feet Stink?

MedlinePlus

... organic acids — they also produce stuff called volatile sulfur compounds. Sulfur compounds usually are powerful and awful smelling. If ... smelled a rotten egg, you know what volatile sulfur compounds smell like. What Can You Do? There’s ...

Analyzing volatile compounds in dairy products

USDA-ARS?s Scientific Manuscript database

Volatile compounds give the first indication of the flavor in a dairy product. Volatiles are isolated from the sample matrix and then analyzed by chromatography, sensory methods, or an electronic nose. Isolation may be performed by solvent extraction or headspace analysis, and gas chromatography i...

BIOCONCENTRATION FACTORS FOR VOLATILE ORGANIC COMPOUNDS IN VEGETATION

EPA Science Inventory

Samples of air and leaves were taken at the University of Nevada-Las Vegas campus and analyzed for volatile organic compounds using vacuum distillation coupled with gas chromatography/mass spectrometry. The data were used to estimate the bioconcentration of volatile organic compo...

Electroantennographic and behavioral responses of the sphinx moth Manduca sexta to host plant headspace volatiles.

PubMed

Fraser, Ann M; Mechaber, Wendy L; Hildebrand, John G

2003-08-01

Coupled gas chromatography with electroantennographic detection (GC-EAD) using antennae of adult female Manduca sexta was employed to screen for olfactory stimulants present in headspace collections from four species of larval host plants belonging to two families: Solanaceae--Lycopersicon esculentum (tomato), Capiscum annuum (bell pepper), and Datura wrightii; and Martyniaceae--Pronboscideaparviflora. Headspace volatiles were collected from undamaged foliage of potted, living plants. GC-EAD revealed 23 EAD-active compounds, of which 15 were identified by GC-mass spectrometry. Identified compounds included aliphatic, aromatic, and terpenoid compounds bearing a range of functional groups. Nine EAD-active compounds were common to all four host plant species: (Z)-3-hexenyl acetate, nonanal, decanal, phenylacetaldehyde, methyl salicylate, benzyl alcohol, geranyl acetone, (E)-nerolidol, and one unidentified compound. Behavioral responses of female moths to an eight-component synthetic blend of selected tomato headspace volatiles were tested in a laboratory wind tunnel. Females were attracted to the blend. A comparison of responses from antennae of males and females to bell pepper headspace volatiles revealed that males responded to the same suite of volatiles as females, except for (Z)-3-hexenyl benzoate. EAD responses of males also were lower for (Z)-and (E)-nerolidol and one unidentified compound. Electroantennogram EAG dose-response curves for the 15 identified EAD-active volatiles were recorded. At the higher test doses (10-100 microg), female antennae yielded larger EAG responses to terpenoids and to aliphatic and aromatic esters. Male antennae did respond to the higher doses of (Z)-3-hexenyl benzoate, indicating that they can detect this compound. On the basis of ubiquity of the EAD-active volatiles identified to date in host plant headspace collections, we suggest that M. sexta uses a suite of volatiles to locate and identify appropriate host plants.

Deodorization of Garlic Breath by Foods, and the Role of Polyphenol Oxidase and Phenolic Compounds.

PubMed

Mirondo, Rita; Barringer, Sheryl

2016-10-01

Garlic causes a strong garlic breath that may persist for almost a day. Therefore, it is important to study deodorization techniques for garlic breath. The volatiles responsible for garlic breath include diallyl disulfide, allyl mercaptan, allyl methyl disulfide, and allyl methyl sulfide. After eating garlic, water (control), raw, juiced or heated apple, raw or heated lettuce, raw or juiced mint leaves, or green tea were consumed immediately. The levels of the garlic volatiles on the breath were analyzed from 1 to 60 min by selected ion flow tube mass spectrometry (SIFT-MS). Garlic was also blended with water (control), polyphenol oxidase (PPO), rosemarinic acid, quercetin or catechin, and the volatiles in the headspace analyzed from 3 to 40 min by SIFT-MS. Raw apple, raw lettuce, and mint leaves significantly decreased all of the garlic breath volatiles in vivo. The proposed mechanism is enzymatic deodorization where volatiles react with phenolic compounds. Apple juice and mint juice also had a deodorizing effect on most of the garlic volatiles but were generally not as effective as the raw food, probably because the juice had enzymatic activity but the phenolic compounds had already polymerized. Both heated apple and heated lettuce produced a significant reduction of diallyl disulfide and allyl mercaptan. The presence of phenolic compounds that react with the volatile compounds even in the absence of enzymes is the most likely mechanism. Green tea had no deodorizing effect on the garlic volatile compounds. Rosmarinic acid, catechin, quercetin, and PPO significantly decreased all garlic breath volatiles in vitro. Rosmarinic acid was the most effective at deodorization. © 2016 Institute of Food Technologists®.

Pesticide nonextractable residue formation in soil: insights from inverse modeling of degradation time series.

PubMed

Loos, Martin; Krauss, Martin; Fenner, Kathrin

2012-09-18

Formation of soil nonextractable residues (NER) is central to the fate and persistence of pesticides. To investigate pools and extent of NER formation, an established inverse modeling approach for pesticide soil degradation time series was evaluated with a Monte Carlo Markov Chain (MCMC) sampling procedure. It was found that only half of 73 pesticide degradation time series from a homogeneous soil source allowed for well-behaved identification of kinetic parameters with a four-pool model containing a parent compound, a metabolite, a volatile, and a NER pool. A subsequent simulation indeed confirmed distinct parameter combinations of low identifiability. Taking the resulting uncertainties into account, several conclusions regarding NER formation and its impact on persistence assessment could nonetheless be drawn. First, rate constants for transformation of parent compounds to metabolites were correlated to those for transformation of parent compounds to NER, leading to degradation half-lives (DegT50) typically not being larger than disappearance half-lives (DT50) by more than a factor of 2. Second, estimated rate constants were used to evaluate NER formation over time. This showed that NER formation, particularly through the metabolite pool, may be grossly underestimated when using standard incubation periods. It further showed that amounts and uncertainties in (i) total NER, (ii) NER formed from the parent pool, and (iii) NER formed from the metabolite pool vary considerably among data sets at t→∞, with no clear dominance between (ii) and (iii). However, compounds containing aromatic amine moieties were found to form significantly more total NER when extrapolating to t→∞ than the other compounds studied. Overall, our study stresses the general need for assessing uncertainties, identifiability issues, and resulting biases when using inverse modeling of degradation time series for evaluating persistence and NER formation.

Catalyst for Oxidation of Volatile Organic Compounds

NASA Technical Reports Server (NTRS)

Wood, George M. (Inventor); Upchurch, Billy T. (Inventor); Schryer, David R. (Inventor); Davis, Patricia P. (Inventor); Kielin, Erik J. (Inventor); Brown, Kenneth G. (Inventor); Schyryer, Jacqueline L. (Inventor); DAmbrosia, Christine M. (Inventor)

2000-01-01

Disclosed is a process for oxidizing volatile organic compounds to carbon dioxide and water with the minimal addition of energy. A mixture of the volatile organic compound and an oxidizing agent (e.g. ambient air containing the volatile organic compound) is exposed to a catalyst which includes a noble metal dispersed on a metal oxide which possesses more than one oxidation state. Especially good results are obtained when the noble metal is platinum, and the metal oxide which possesses more than one oxidation state is tin oxide. A promoter (i.e., a small amount of an oxide of a transition series metal) may be used in association with the tin oxide to provide very beneficial results.

Volatile organic compound emissions from green waste composting: Characterization and ozone formation

NASA Astrophysics Data System (ADS)

Kumar, Anuj; Alaimo, Christopher P.; Horowitz, Robert; Mitloehner, Frank M.; Kleeman, Michael J.; Green, Peter G.

2011-04-01

Composting of green waste separated from the disposed solid waste stream reduces biodegradable inputs into landfills, and contributes valuable soil amendments to agriculture. Agencies in regions with severe air quality challenges, such as California's San Joaquin Valley (SJV), have raised concerns about gases emitted during the composting process, which are suspected to contribute to persistent high levels of ground-level ozone formation. The goal of the current study is to thoroughly characterize volatile organic compound (VOC) emissions from green waste compost piles of different ages (fresh tipped piles, 3-6 day old windrows, and 2-3 week old windrows). Multiple sampling and analytical approaches were applied to ensure the detection of most gaseous organic components emitted. More than 100 VOCs were detected and quantified in this study, including aliphatic alkanes, alkenes, aromatic hydrocarbons, biogenic organics, aldehydes, ketones, alcohols, furans, acids, esters, ether, halogenated hydrocarbons and dimethyl disulfide (DMDS). Alcohols were found to be the dominating VOC in the emissions from a compost pile regardless of age, with fluxes ranging from 2.6 to 13.0 mg m -2 min -1 with the highest emissions coming from the younger composting windrows (3-6 days). Average VOC emissions other than alcohols were determined to be 2.3 mg m -2 min -1 from younger windows, which was roughly two times higher than either the fresh tipping pile (1.2 mg m -2 min -1) or the older windrows (1.4 mg m -2 min -1). It was also observed that the older windrows emit a slightly larger proportion of more reactive compounds. Approximately 90% of the total VOCs were found to have maximum incremental reactivity of less than 2. Net ozone formation potential of the emissions was also assessed.

Exhaust emissions of volatile organic compounds of powered two-wheelers: effect of cold start and vehicle speed. Contribution to greenhouse effect and tropospheric ozone formation.

PubMed

Costagliola, M Antonietta; Murena, Fabio; Prati, M Vittoria

2014-01-15

Powered two-wheeler (PTW) vehicles complying with recent European type approval standards (stages Euro 2 and Euro 3) were tested on chassis dynamometer in order to measure exhaust emissions of about 25 volatile organic compounds (VOCs) in the range C1-C7, including carcinogenic compounds as benzene and 1,3-butadiene. The fleet consists of a moped (engine capacity ≤ 50 cm(3)) and three fuel injection motorcycles of different engine capacities (150, 300 and 400 cm(3)). Different driving conditions were tested (US FPT cycle, constant speed). Due to the poor control of the combustion and catalyst efficiency, moped is the highest pollutant emitter. In fact, fuel injection strategy and three way catalyst with lambda sensor are able to reduce VOC motorcycles' emission of about one order of magnitude with respect to moped. Cold start effect, that is crucial for the assessment of actual emission of PTWs in urban areas, was significant: 30-51% of extra emission for methane. In the investigated speed range, moped showed a significant maximum of VOC emission factor at minimum speed (10 km/h) and a slightly decreasing trend from 20 to 60 km/h; motorcycles showed on the average a less significant peak at 10 km/h, a minimum at 30-40 km/h and then an increasing trend with a maximum emission factor at 90 km/h. Carcinogenic VOCs show the same pattern of total VOCs. Ozone Formation Potential (OFP) was estimated by using Maximum Incremental Reactivity scale. The greatest contribution to tropospheric ozone formation comes from alkenes group which account for 50-80% to the total OFP. VOC contribution effect on greenhouse effect is negligible with respect to CO2 emitted. © 2013.

Volatile organic compound mixing ratios above Beijing in November and December 2016

NASA Astrophysics Data System (ADS)

Acton, William; Shaw, Marvin; Huang, Zhonghui; Wang, Zhaoyi; Wang, Xinming; Zhang, Yanli; Davison, Brian; Langford, Ben; Mullinger, Neil; Nemitz, Eiko; Fu, Pingqing; Squires, Freya; Carpenter, Lucy; Lewis, Alastair; Hewitt, Nick

2017-04-01

Volatile organic compounds (VOCs) are emitted into the atmosphere from vegetation and anthropogenic sources such as fossil fuel combustion, biomass burning and the evaporation of petroleum products. These compounds play an important role in the chemistry of the lower atmosphere through secondary organic aerosol (SOA) formation and facilitating the formation of tropospheric ozone. As well as their indirect impact on human health via the formation of ozone and SOA, some VOCs, including benzene, directly affect human health adversely. Here we report VOC mixing ratios measured in Beijing during a 5 week intensive field campaign from the 7th November to the 10th December 2016. This work was carried out as part of the Sources and Emissions of Air Pollutants in Beijing (AIRPOLL-Beijing) work project within the Air Pollution and Human Health in a Developing Megacity (APHH-Beijing) research programme. APHH is a large multi-institutional study which aims to record the concentrations and identify the sources of urban air pollutants in Beijing, determine exposure, understand their effects on human health, and to identify solutions. VOC mixing ratios were recorded using a Proton Transfer Reaction-Time of Flight-Mass Spectrometer (PTR-ToF-MS, Ionicon Analytik) and a Selected Ion Flow Tube-Mass Spectrometer (SIFT-MS, SYFT Technologies). During the measurement period Beijing was subject to multiple pollution events that alternated with periods of relatively good air quality, allowing the VOCs within the polluted air masses to be identified and quantified. VOCs were sampled at 102 m with additional gradient measurements made at 3, 15, 32 and 64 m providing a vertical profile of VOC mixing ratios. Mixing ratios of methanol, acetonitrile, acetaldehyde, acetone, isoprene and aromatics species will be reported together with a discussion of potential sources. Comparisons will then be drawn with other large cities.

Influence of rearing conditions on the volatile compounds of cooked fillets of Silurus glanis (European catfish).

PubMed

Hallier, Arnaud; Prost, Carole; Serot, Thierry

2005-09-07

Volatile compounds of cooked fillets of Silurus glanis reared under two conditions occurring in France were studied. They were extracted by dynamic headspace, identified by gas chromatography/mass spectrometry, and quantified by gas chromatography-flame ionization detection. Odor active volatile compounds were characterized by gas chromatography-olfactometry. Sixty volatile compounds were detected in dynamic headspace extracts, among which 33 were odor active. Rearing conditions affected their estimated concentrations and their odor intensities, but very few qualitative differences were exhibited (only seven volatile compounds were concerned). A good correlation between quantitative and olfactometric results is shown. 2-Methylisoborneol and (E)-2-hexenal were less represented in OUTDOOR extracts, while 2-butanone was less represented in INDOOR extracts. In addition, olfactometric results can be closely related to those previously obtained by sensory analysis. Boiled potato sensory odor of the silurus cooked fillets can be related to (Z)-4-heptenal and methional, and buttery odor can be related to 2,3-butanedione, an unknown compound (RI = 1010), and 2,3-pentadione.

Aroma content of fresh basil (Ocimum basilicum L.) leaves is affected by light reflected from colored mulches.

PubMed

Loughrin, John H; Kasperbauer, Michael J

2003-04-09

Sweet basil (Ocimum basilicum L.) is an herb that is used to add a distinct aroma and flavor to food. Volatile compounds emitted from fully expanded fresh leaves grown in drip-irrigated plots that were covered with six colors of mulch were compared. The colors reflected a range of photosynthetic photon flux, far-red, red, and blue light from the soil surface to developing leaves. Our objective was to determine whether reflection from the different colors could influence concentrations of volatile compounds emitted from the fresh leaves. Volatile compounds were isolated by headspace sampling and quantified by gas chromatography. Twenty-six compounds were identified, of which the terpenoids linalool and 1,8-cineole comprised more than 50% of the total yield. Concentrations of volatile compounds from leaves that developed over green, blue, yellow, white, and red mulches followed the same patterns as they did for air-dried leaves of the same cultivar. However, the concentration of volatile compounds from fresh leaves was about 50-fold higher than those found in the previous study of air-dried leaves.

[Estimate of the formation potential of secondary organic aerosol in Beijing summertime].

PubMed

Lü, Zi-Feng; Hao, Ji-Ming; Duan, Jing-Chun; Li, Jun-Hua

2009-04-15

Fractional aerosol coefficients (FAC) are used in conjunction with measurements of volatile organic compounds (VOC) during ozone episodes to estimate the formation potential of secondary organic aerosols (SOA) in the summertime of Beijing. The estimation is based on the actual atmospheric conditions of Beijing, and benzene and isoprene are considered as the precursors of SOA. The results show that 31 out of 70 measured VOC species are SOA precursors, and the total potential SOA formation is predicted to be 8.48 microg/m3, which accounts for 30% of fine organic particle matter. Toluene, xylene, pinene, ethylbenzene and n-undecane are the 5 largest contributors to SOA production and account for 20%, 22%, 14%, 9% and 4% of total SOA production, respectively. The anthropogenic aromatic compounds, which yield 76% of the calculated SOA, are the major source of SOA. The biogenic alkenes, alkanes and carbonyls produce 16%, 7% and 1% of SOA formation, respectively. The major components of produced SOA are expected to be aromatic compounds, aliphatic acids, carbonyls and aliphatic nitrates, which contribute to 72%, 14%, 11% and 3% of SOA mass, respectively. The SOA precursors have relatively low atmospheric concentrations and low ozone formation potential. Hence, SOA formation potential of VOC species, in addition to their atmospheric concentrations and ozone formation potential, should be considered in policy making process of VOCs control.

The meteoritic record of presolar and early solar system organic chemistry. [Abstract only

NASA Technical Reports Server (NTRS)

Cronin, John R.; Pizzarello, Sandra

1994-01-01

Carbon, hydrogen, and nitrogen isotopic analyses of various classes of organic compounds done in collaboration with Epstein and Krishnamurthy (Caltech) have shown these compounds to be enriched to varying degrees in the heavier isotopes. These results, in particular the large deuterium enrichments, have been interpreted as indicating an interstellar origin for the meteorite compounds or their precursors. Such isotopic fractionations, of hydrogen especially, are characteristic of low temperature ion-molecule reactions in cold interstellar clouds. There is also evidence from the large corresponding suites of alpha-amino and alpha-hydroxy acids found in meteorites suggesting that aqueous phase chemistry on the meteorite parent body played an important role in the formation of these compounds. These data support the hypothesis that interstellar compounds survived in the solar nebula at a radial distance corresponding to the asteroid belt, were incorporated into the parent body in icy, volatile-rich, planetesinals, and underwent further reactions during a period of aqueous activity within the early parent body to give the present suite of meteorite compounds. This formation hypothesis will be discussed and the results of recent isotopic and molecular analyses bearing on it will be presented.

GLOBAL INVENTORY OF VOLATILE COMPOUND EMISSIONS FROM ANTHROPOGENIC SOURCES

EPA Science Inventory

The report describes a global inventory anthropogenic volatile organic compound (VOC) emissions that includes a separate inventory for each of seven pollutant groups--paraffins, olefins, aromatics, formaldehyde, other aldehydes, other aromatics, and marginally reactive compounds....

Removal of volatile organic compounds using amphiphilic cyclodextrin-coated polypropylene.

PubMed

Lumholdt, Ludmilla; Fourmentin, Sophie; Nielsen, Thorbjørn T; Larsen, Kim L

2014-01-01

Polypropylene nonwovens were functionalised using a self-assembled, amphiphilic cyclodextrin coating and the potential for water purification by removal of pollutants was studied. As benzene is one of the problematic compounds in the Water Framework Directive, six volatile organic compounds (benzene and five benzene-based substances) were chosen as model compounds. The compounds were tested as a mixture in order to provide a more realistic situation since the wastewater will be a complex mixture containing multiple pollutants. The volatile organic compounds are known to form stable inclusion complexes with cyclodextrins. Six different amphiphilic cyclodextrin derivatives were synthesised in order to elucidate whether or not the uptake abilities of the coating depend on the structure of the derivative. Headspace gas chromatography was used for quantification of the uptake exploiting the volatile nature of benzene and its derivatives. The capacity was shown to increase beyond the expected stoichiometries of guest-host complexes with ratios of up to 16:1.

40 CFR 52.2420 - Identification of plan.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Enforceable, Implementation Plan, Potential to Emit, State Enforceable, Volatile Organic Compound 4/1/96 3/12..., Regulation of the Board, These regulations. Terms Revised—Good Engineering Practice, Person, Volatile organic... pressure, Vapor pressure, Volatile organic compounds. Terms Removed: Air Quality Maintenance Area. 5-10-20...

Rapid volatile metabolomics and genomics in large strawberry populations segregating for aroma

USDA-ARS?s Scientific Manuscript database

Volatile organic compounds (VOCs) in strawberry (Fragaria spp.) represent a large portion of the fruit secondary metabolome, and contribute significantly to aroma, flavor, disease resistance, pest resistance and overall fruit quality. Understanding the basis for volatile compound biosynthesis and it...

MODEL DEVELOPMENT AND TESTING FOR SEMI-VOLATILES (ATRAZINE)

EPA Science Inventory

The Community Multi-Scale Air Quality (CMAQ) model, air quality model within EPA's Models-3 system, can be adapted to simulate the fate of semi-volatile compounds that are emitted into the atmosphere. "Semi-volatile" refers to compounds that partition their mass between two ph...

Floral scent in natural hybrids of Ipomopsis (Polemoniaceae) and their parental species

PubMed Central

Bischoff, Mascha; Jürgens, Andreas; Campbell, Diane R.

2014-01-01

Background and Aims Floral traits, such as floral volatiles, can contribute to pre-zygotic reproductive isolation by promoting species-specific pollinator foraging. When hybrid zones form, floral traits could also influence post-zygotic isolation. This study examined floral volatiles in parental species and natural hybrids in order to explore potential scent mediation of pre-zygotic and post-zygotic isolation. Methods Floral bouquets were analysed for the sister species Ipomopsis aggregata and I. tenuituba and their natural hybrids at two contact sites differing in both hybridization rate and temporal foraging pattern of hawkmoth pollinators. Floral volatiles were quantified in diurnal and nocturnal scent samples using gas chromatography–mass spectrometry. Key Results The bouquets of parental species and hybrids showed qualitative overlap. All flowers emitted similar sets of monoterpenoid, sesquiterpenoid, aliphatic and benzenoid compounds, but separated into groups defined by multivariate analysis of quantitative emissions. The parental species differed most strikingly in the nitrogenous compound indole, which was found almost exclusively in nocturnal bouquets of I. tenuituba. Natural hybrid bouquets were highly variable, and showed emission rates of several compounds that appeared transgressive. However, indole emission rates were intermediate in the hybrids compared with rates in the parents. Volatile bouquets at the contact site with lower hybridization did not show greater species specificity in overall scent emission, but I. tenuituba presented a stronger indole signal during peak hawkmoth activity at that site. Conclusions The two species of Ipomopsis differed in patterns of floral bouquets, with indole emitted in nocturnal I. tenuituba, but not in I. aggregata. Natural hybrid bouquets were not consistently intermediate between the parents, although hybrids were intermediate in indole emission. The indole signal could potentially serve as a hawkmoth attractant that mediates reproductive isolation both before and after hybrid formation. PMID:24355404

Aqueous Oxidation of Green Leaf Volatiles as a Source of Secondary Organic Aerosol

NASA Astrophysics Data System (ADS)

Richards-Henderson, N. K.; Hansel, A.; Pham, A. T.; Vempati, H. S.; Valsaraj, K. T.; Anastasio, C.

2013-12-01

Vegetation emits volatile oxygenated hydrocarbons - the green leaf volatiles (GLVs) - which are formed from the biochemical conversion of linoleic and linolenic acids within plant cells. Stress or damage to vegetation can significantly elevate emission fluxes of these compounds, some of which are fairly water soluble. Aqueous-phase reactions of the GLVs with photochemically generated oxidants - such as hydroxyl radical (OH), singlet oxygen (1O2) and excited triplet states of organic compounds (3C*) _ might then form low-volatility products that can act as secondary organic aerosol (SOA). In order to determine if GLVs can be a significant source of secondary organic carbon in fogwater, studies of GLVs in laboratory solutions are needed to elucidate the oxidation kinetics and the corresponding SOA mass yields. In this study we are determining the second-order rate constants, and SOA mass yields, for five GLVs (cis-3-hexen-1-ol, cis-3-hexenylacetate, methyl salicylate, methyl jasmonate, and 2-methyl-3-butene-2-ol) reacting with OH,1O2 and 3C*. Experiments are performed at relevant fog water pHs, temperatures, and oxidant concentrations. Rate constants are determined using a relative rate approach in which the decay of GLVs and reference compounds are monitored as function of time by HPLC. The capacity of GLVs to form aqueous SOA was determined by following the formation of their decomposition products with HPLC-UV/DAD and HPLC-ESI/MS. SOA mass yields are measured gravimetrically from laboratory solutions containing atmospherically relevant concentrations of photooxidants and GLVs, and irradiated with simulated sunlight. We will use our results to assess the potential contribution of aqueous GLV reactions as a source of SOA in cloudy or foggy atmospheres.

Next Generation Offline Approaches to Trace Gas-Phase Organic Compound Speciation: Sample Collection and Analysis

NASA Astrophysics Data System (ADS)

Sheu, R.; Marcotte, A.; Khare, P.; Ditto, J.; Charan, S.; Gentner, D. R.

2017-12-01

Intermediate-volatility and semi-volatile organic compounds (I/SVOCs) are major precursors to secondary organic aerosol, and contribute to tropospheric ozone formation. Their wide volatility range, chemical complexity, behavior in analytical systems, and trace concentrations present numerous hurdles to characterization. We present an integrated sampling-to-analysis system for the collection and offline analysis of trace gas-phase organic compounds with the goal of preserving and recovering analytes throughout sample collection, transport, storage, and thermal desorption for accurate analysis. Custom multi-bed adsorbent tubes are used to collect samples for offline analysis by advanced analytical detectors. The analytical instrumentation comprises an automated thermal desorption system that introduces analytes from the adsorbent tubes into a gas chromatograph, which is coupled with an electron ionization mass spectrometer (GC-EIMS) and other detectors. In order to optimize the collection and recovery for a wide range of analyte volatility and functionalization, we evaluated a variety of commercially-available materials, including Res-Sil beads, quartz wool, glass beads, Tenax TA, and silica gel. Key properties for optimization include inertness, versatile chemical capture, minimal affinity for water, and minimal artifacts or degradation byproducts; these properties were assessed with a diverse mix of traditionally-measured and functionalized analytes. Along with a focus on material selection, we provide recommendations spanning the entire sampling-and-analysis process to improve the accuracy of future comprehensive I/SVOC measurements, including oxygenated and other functionalized I/SVOCs. We demonstrate the performance of our system by providing results on speciated VOCs-SVOCs from indoor, outdoor, and chamber studies that establish the utility of our protocols and pave the way for precise laboratory characterization via a mix of detection methods.

Effect of Vertical Shoot-Positioned, Scott-Henry, Geneva Double-Curtain, Arch-Cane, and Parral Training Systems on the Volatile Composition of Albariño Wines.

PubMed

Vilanova, Mar; Genisheva, Zlatina; Tubio, Miguel; Álvarez, Katia; Lissarrague, Jose Ramón; Oliveira, José Maria

2017-09-08

Viticultural practices influence both grape and wine quality. The influence of training systems on volatile composition was investigated for Albariño wine from Rías Baixas AOC in Northwest Spain. The odoriferous contribution of the compounds to the wine aroma was also studied. Volatile compounds belonging to ten groups (alcohols, C₆-compounds, ethyl esters, acetates, terpenols, C 13 -norisoprenoids, volatile phenols, volatile fatty acids, lactones and carbonyl compounds) were determined in Albariño wines from different training systems, Vertical Shoot-Positioned (VSP), Scott-Henry (SH), Geneva Double-Curtain (GDC), Arch-Cane (AC), and Parral (P) during 2010 and 2011 vintages. Wines from GDC showed the highest total volatile composition with the highest concentrations of alcohols, ethyl esters, fatty acids, and lactones families. However, the highest levels of terpenes and C 13 -norisoprenoids were quantified in the SH system. A fruitier aroma was observed in Albariño wines from GDC when odor activity values were calculated.

Age matters: the effects of volatile organic compounds emitted by Trichoderma atroviride on plant growth.

PubMed

Lee, Samantha; Hung, Richard; Yap, Melanie; Bennett, Joan W

2015-06-01

Studying the effects of microbial volatile organic compounds (VOCs) on plant growth is challenging because the production of volatiles depends on many environmental factors. Adding to this complexity, the method of volatile exposure itself can lead to different responses in plants and may account for some of the contrasting results. In this work, we present an improved experimental design, a plate-within-a-plate method, to study the effects of VOCs produced by filamentous fungi. We demonstrate that the plant growth response to VOCs is dependent on the age of the plant and fungal cultures. Plants exposed to volatiles emitted by 5-day-old Trichoderma atroviride for 14 days exhibited inhibition, while plants exposed to other exposure conditions had growth promotion or no significant change. Using GC-MS, we compared fungal volatile emission of 5-day-old and 14-day-old T. atroviride. As the fungi aged, a few compounds were no longer detected, but 24 new compounds were discovered.

Introductory lecture: atmospheric organic aerosols: insights from the combination of measurements and chemical transport models.

PubMed

Pandis, Spyros N; Donahue, Neil M; Murphy, Benjamin N; Riipinen, Ilona; Fountoukis, Christos; Karnezi, Eleni; Patoulias, David; Skyllakou, Ksakousti

2013-01-01

The formation, atmospheric evolution, properties, and removal of organic particulate matter remain some of the least understood aspects of atmospheric chemistry despite the importance of organic aerosol (OA) for both human health and climate change. Here, we summarize our recent efforts to deal with the chemical complexity of the tens of thousands of organic compounds in the atmosphere using the volatility-oxygen content framework (often called the 2D-Volatility Basis Set, 2D-VBS). Our current ability to measure the ambient OA concentration as a function of its volatility and oxygen to carbon (O:C) ratio is evaluated. The combination of a thermodenuder, isothermal dilution and Aerosol Mass Spectrometry (AMS) together with a mathematical aerosol dynamics model is a promising approach. The development of computational modules based on the 2D-VBS that can be used in chemical transport models (CTMs) is described. Approaches of different complexity are tested against ambient observations, showing the challenge of simulating the complex chemical evolution of atmospheric OA. The results of the simplest approach describing the net change due to functionalization and fragmentation are quite encouraging, reproducing both the observed OA levels and O : C in a variety of conditions. The same CTM coupled with source-apportionment algorithms can be used to gain insights into the travel distances and age of atmospheric OA. We estimate that the average age of OA near the ground in continental locations is 1-2 days and most of it was emitted (either as precursor vapors or particles) hundreds of kilometers away. Condensation of organic vapors on fresh particles is critical for the growth of these new particles to larger sizes and eventually to cloud condensation nuclei (CCN) sizes. The semivolatile organics currently simulated by CTMs are too volatile to condense on these tiny particles with high curvature. We show that chemical aging reactions converting these semivolatile compounds to extremely low volatility compounds can explain the observed growth rates of new particles in rural environments.

Global detection and analysis of volatile components from sun-dried and sulfur-fumigated herbal medicine by comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry.

PubMed

Cao, Gang; Cai, Hao; Cong, Xiaodong; Liu, Xiao; Ma, Xiaoqing; Lou, Yajing; Qin, Kunming; Cai, Baochang

2012-08-21

The sulfur-fumigation process can induce changes in the contents of volatile compounds and the chemical transformation of herbal medicines. Although literature has reported many methods for analyzing volatile target compounds from herbal medicine, all of them are largely limited to target compounds and sun-dried samples. This study provides a comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC×GC-TOF/MS) method based on a chemical profiling approach to identify non-target and target volatile compounds from sun-dried and sulfur-fumigated herbal medicine. Using Chrysanthemum morifolium as a model herbal medicine, the combined power of this approach is illustrated by the identification of 209 and 111 volatile compounds with match quality >80% from sun-dried and sulfur-fumigated Chrysanthemum morifolium, respectively. The study has also shown that sulfur-fumigated samples showed a significant loss of the main active compounds and a more destructive fingerprint profile compared to the sun-dried ones. 50 volatile compounds were lost in the sulfur-fumigated Chrysanthemum morifolium sample. The approach and methodology reported in this paper would be useful for identifying complicated target and non-target components from various complex mixtures such as herbal medicine and its preparations, biological and environmental samples. Furthermore, it can be applied for the intrinsic quality control of herbal medicine and its preparations.

Determination of volatile marker compounds in raw ham using headspace-trap gas chromatography.

PubMed

Bosse Née Danz, Ramona; Wirth, Melanie; Konstanz, Annette; Becker, Thomas; Weiss, Jochen; Gibis, Monika

2017-03-15

A simple, reliable and automated method was developed and optimized for qualification and quantification of aroma-relevant volatile marker compounds of North European raw ham using a headspace (HS)-Trap gas chromatography-mass spectrometry (GC-MS) and GC-flame ionization detector (FID) analysis. A total of 38 volatile compounds were detected with this HS-Trap GC-MS method amongst which the largest groups were ketones (12), alcohols (8), hydrocarbons (7), aldehydes (6) and esters (3). The HS-Trap GC-FID method was optimized for the parameters: thermostatting time and temperature, vial and desorption pressure, number of extraction cycles and salt addition. A validation for 13 volatile marker compounds with limits of detection in ng/g was carried out. The optimized method can serve as alternative to conventional headspace and solid phase micro extraction methods and allows users to determine volatile compounds in raw hams making it of interest to industrial and academic meat scientists. Copyright © 2016 Elsevier Ltd. All rights reserved.

Beer volatile compounds and their application to low-malt beer fermentation.

PubMed

Kobayashi, Michiko; Shimizu, Hiroshi; Shioya, Suteaki

2008-10-01

Low-malt beers, in which the amount of wort is adjusted to less than two-thirds of that in regular beer, are popular in the Japanese market because the flavor of low-malt beer is similar to that of regular beer but the price lesser than that of regular beer. There are few published articles about low-malt beer. However, in the production process, there are many similarities between low-malt and regular beer, e.g., the yeast used in low-malt beer fermentation is the same as that used for regular beer. Furthermore, many investigations into regular beer are applicable to low-malt beer production. In this review, we focus on production of volatile compounds, and various studies that are applicable to regular and low-malt beer. In particular, information about metabolism of volatile compounds in yeast cells during fermentation, volatile compound measurement and estimation methods, and control of volatile compound production are discussed in this review, which concentrates on studies published in the last 5-6 years.

Solid-phase microextraction for the determination of volatile compounds in the spoilage of raw ground beef.

PubMed

Pérez, Rosa Ana; Rojo, Maria Dolores; González, Gema; De Lorenzo, Cristina

2008-01-01

A method using solid-phase microextraction (SPME) and gas chromatography/mass spectrometry was developed and applied to the determination of volatile compounds generated in meat, at different times, from ground beef stored under refrigeration. Selection of the extractive fiber, extraction time, and headspace (HS) or direct extraction was optimized for the determination of volatile compounds from ground meat. Various fibers were investigated, and carboxen/polydimethylsiloxane was selected for these analyses. The HS analysis of the solid sample by HS-SPME produced a higher volatile signal than did direct-SPME. The meat samples were stored under refrigeration and analyzed after 0, 3, and 6 days of storage. These analyses at different times showed important changes in the volatile profile of the evaluated samples. The ketones 3-hydroxy-2-butanone and 2,3-butanedione, and the alcohol 3-methyl-1-butanol were the most representative compounds generated during the meat storage. In general, compounds associated with a butter off-flavor were detected during the storage of raw ground beef.

Volatility characterization of nanoparticles from single and dual-fuel low temperature combustion in compression ignition engines

DOE PAGES

Lucachick, Glenn; Curran, Scott; Storey, John Morse; ...

2016-03-10

Our work explores the volatility of particles produced from two diesel low temperature combustion (LTC) modes proposed for high-efficiency compression ignition engines. It also explores mechanisms of particulate formation and growth upon dilution in the near-tailpipe environment. Moreover, the number distribution of exhaust particles from low- and mid-load dual-fuel reactivity controlled compression ignition (RCCI) and single-fuel premixed charge compression ignition (PPCI) modes were experimentally studied over a gradient of dilution temperature. Particle volatility of select particle diameters was investigated using volatility tandem differential mobility analysis (V-TDMA). Evaporation rates for exhaust particles were compared with V-TDMA results for candidate pure n-alkanesmore » to identify species with similar volatility characteristics. The results show that LTC particles are mostly comprised of material with volatility similar to engine oil alkanes. V-TDMA results were used as inputs to an aerosol condensation and evaporation model to support the finding that smaller particles in the distribution are comprised of lower volatility material than large particles under primary dilution conditions. Although the results show that saturation levels are high enough to drive condensation of alkanes onto existing particles under the dilution conditions investigated, they are not high We conclude that observed particles from LTC operation must grow from low concentrations of highly non-volatile compounds present in the exhaust.« less

Atmospheric Chemistry of Micrometeoritic Organic Compounds

NASA Technical Reports Server (NTRS)

Kress, M. E.; Belle, C. L.; Pevyhouse, A. R.; Iraci, L. T.

2011-01-01

Micrometeorites approx.100 m in diameter deliver most of the Earth s annual accumulation of extraterrestrial material. These small particles are so strongly heated upon atmospheric entry that most of their volatile content is vaporized. Here we present preliminary results from two sets of experiments to investigate the fate of the organic fraction of micrometeorites. In the first set of experiments, 300 m particles of a CM carbonaceous chondrite were subject to flash pyrolysis, simulating atmospheric entry. In addition to CO and CO2, many organic compounds were released, including functionalized benzenes, hydrocarbons, and small polycyclic aromatic hydrocarbons. In the second set of experiments, we subjected two of these compounds to conditions that simulate the heterogeneous chemistry of Earth s upper atmosphere. We find evidence that meteor-derived compounds can follow reaction pathways leading to the formation of more complex organic compounds.

Physiology, ecology and industrial applications of aroma formation in yeast

PubMed Central

Dzialo, Maria C; Park, Rahel; Steensels, Jan; Lievens, Bart; Verstrepen, Kevin J

2017-01-01

Abstract Yeast cells are often employed in industrial fermentation processes for their ability to efficiently convert relatively high concentrations of sugars into ethanol and carbon dioxide. Additionally, fermenting yeast cells produce a wide range of other compounds, including various higher alcohols, carbonyl compounds, phenolic compounds, fatty acid derivatives and sulfur compounds. Interestingly, many of these secondary metabolites are volatile and have pungent aromas that are often vital for product quality. In this review, we summarize the different biochemical pathways underlying aroma production in yeast as well as the relevance of these compounds for industrial applications and the factors that influence their production during fermentation. Additionally, we discuss the different physiological and ecological roles of aroma-active metabolites, including recent findings that point at their role as signaling molecules and attractants for insect vectors. PMID:28830094

Different methods for volatile sampling in mammals

PubMed Central

Möller, Manfred; Marcillo, Andrea; Einspanier, Almuth; Weiß, Brigitte M.

2017-01-01

Previous studies showed that olfactory cues are important for mammalian communication. However, many specific compounds that convey information between conspecifics are still unknown. To understand mechanisms and functions of olfactory cues, olfactory signals such as volatile compounds emitted from individuals need to be assessed. Sampling of animals with and without scent glands was typically conducted using cotton swabs rubbed over the skin or fur and analysed by gas chromatography-mass spectrometry (GC-MS). However, this method has various drawbacks, including a high level of contaminations. Thus, we adapted two methods of volatile sampling from other research fields and compared them to sampling with cotton swabs. To do so we assessed the body odor of common marmosets (Callithrix jacchus) using cotton swabs, thermal desorption (TD) tubes and, alternatively, a mobile GC-MS device containing a thermal desorption trap. Overall, TD tubes comprised most compounds (N = 113), with half of those compounds being volatile (N = 52). The mobile GC-MS captured the fewest compounds (N = 35), of which all were volatile. Cotton swabs contained an intermediate number of compounds (N = 55), but very few volatiles (N = 10). Almost all compounds found with the mobile GC-MS were also captured with TD tubes (94%). Hence, we recommend TD tubes for state of the art sampling of body odor of mammals or other vertebrates, particularly for field studies, as they can be easily transported, stored and analysed with high performance instruments in the lab. Nevertheless, cotton swabs capture compounds which still may contribute to the body odor, e.g. after bacterial fermentation, while profiles from mobile GC-MS include only the most abundant volatiles of the body odor. PMID:28841690

Volatile organic compounds detected in vapor-diffusion samplers placed in sediments along and near the shoreline at Allen Harbor Landfill and Calf Pasture Point, Davisville, Rhode Island, March-April 1998

USGS Publications Warehouse

Lyford, F.P.; Kliever, J.D.; Scott, Clifford

1999-01-01

Volatile organic compounds are present in ground water at the Allen Harbor Landfill and the Calf Pasture Point sites on the former Naval Construction Battalion Center in Davisville, R.I. Vapor-diffusion samplers were used at the two sites during March-April 1998 to identify possible discharge points for contaminants along the shore of Allen Harbor and in two wetland areas near the shore. Results from vapor-diffusion samplers will be used in conjunction with other site information to evaluate proposed ground-water monitoring programs. Volatile organic compounds were detected in 41 of 115 samplers placed along the shoreline at the Allen Harbor Landfill. Trichloroethylene was the principal volatile organic compound detected of eight target compounds. The highest vapor concentration measured exceeded 300,000 parts per billion by volume in an area where TCE was detected in groundwater from nearby monitoring wells. Other chemicals detected in vapor-diffusion samplers included tetrachloroethylene, toluene, and benzene. Concentrations of individual volatile organic compounds were less than 100 parts per billion by volume in most samplers. Volatile organic compounds, principally trichloroethylene, were detected in 7 of 30 samplers placed along the shoreline at Calf Pasture Point; the highest trichloroethylene concentration was 1,900 parts per billion by volume. A trace concentration of tetrachloroethylene was detected in one of the samplers. One of 24 samplers placed in two wetland areas near the shore (suspected discharge areas for ground-water containing volatile organic compounds) detected trichloroethylene at a vapor concentration of 14 parts per billion by volume.

Sensory irritating potency of some microbial volatile organic compounds (MVOCs) and a mixture of five MVOCs.

PubMed

Korpi, A; Kasanen, J P; Alarie, Y; Kosma, V M; Pasanen, A L

1999-01-01

The authors investigated the ability/potencies of 3 microbial volatile organic compounds and a mixture of 5 microbial volatile organic compounds to cause eye and upper respiratory tract irritation (i.e., sensory irritation), with an animal bioassay. The authors estimated potencies by determining the concentration capable of decreasing the respiratory frequency of mice by 50% (i.e., the RD50 value). The RD50 values for 1-octen-3-ol, 3-octanol, and 3-octanone were 182 mg/m3 (35 ppm), 1359 mg/m3 (256 ppm), and 17586 mg/m3 (3360 ppm), respectively. Recommended indoor air levels calculated from the individual RD50 values for 1-octen-3-ol, 3-octanol, and 3-octanone were 100, 1000, and 13000 microg/m3, respectively-values considerably higher than the reported measured indoor air levels for these compounds. The RD50 value for a mixture of 5 microbial volatile organic compounds was also determined and found to be 3.6 times lower than estimated from the fractional concentrations and the respective RD50s of the individual components. The data support the conclusion that a variety of microbial volatile organic compounds may have some synergistic effects for the sensory irritation response, which constrains the interpretation and application of recommended indoor air levels of individual microbial volatile organic compounds. The results also showed that if a particular component of a mixture was much more potent than the other components, it may dominate the sensory irritation effect. With respect to irritation symptoms reported in moldy houses, the results of this study indicate that the contribution of microbial volatile organic compounds to these symptoms seems less than previously supposed.

Formation of highly oxygenated low-volatility products from cresol oxidation

NASA Astrophysics Data System (ADS)

Schwantes, Rebecca H.; Schilling, Katherine A.; McVay, Renee C.; Lignell, Hanna; Coggon, Matthew M.; Zhang, Xuan; Wennberg, Paul O.; Seinfeld, John H.

2017-03-01

Hydroxyl radical (OH) oxidation of toluene produces ring-retaining products: cresol and benzaldehyde, and ring-opening products: bicyclic intermediate compounds and epoxides. Here, first- and later-generation OH oxidation products from cresol and benzaldehyde are identified in laboratory chamber experiments. For benzaldehyde, first-generation ring-retaining products are identified, but later-generation products are not detected. For cresol, low-volatility (saturation mass concentration, C* ˜ 3.5 × 104 - 7.7 × 10-3 µg m-3), first- and later-generation ring-retaining products are identified. Subsequent OH addition to the aromatic ring of o-cresol leads to compounds such as hydroxy, dihydroxy, and trihydroxy methyl benzoquinones and dihydroxy, trihydroxy, tetrahydroxy, and pentahydroxy toluenes. These products are detected in the gas phase by chemical ionization mass spectrometry (CIMS) and in the particle phase using offline direct analysis in real-time mass spectrometry (DART-MS). Our data suggest that the yield of trihydroxy toluene from dihydroxy toluene is substantial. While an exact yield cannot be reported as authentic standards are unavailable, we find that a yield for trihydroxy toluene from dihydroxy toluene of ˜ 0.7 (equal to the reported yield of dihydroxy toluene from o-cresol; Olariu et al., 2002) is consistent with experimental results for o-cresol oxidation under low-NO conditions. These results suggest that even though the cresol pathway accounts for only ˜ 20 % of the oxidation products of toluene, it is the source of a significant fraction (˜ 20-40 %) of toluene secondary organic aerosol (SOA) due to the formation of low-volatility products.

Measurement of volatile plant compounds in field ambient air by thermal desorption-gas chromatography-mass spectrometry.

PubMed

Cai, Xiao-Ming; Xu, Xiu-Xiu; Bian, Lei; Luo, Zong-Xiu; Chen, Zong-Mao

2015-12-01

Determination of volatile plant compounds in field ambient air is important to understand chemical communication between plants and insects and will aid the development of semiochemicals from plants for pest control. In this study, a thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) method was developed to measure ultra-trace levels of volatile plant compounds in field ambient air. The desorption parameters of TD, including sorbent tube material, tube desorption temperature, desorption time, and cold trap temperature, were selected and optimized. In GC-MS analysis, the selected ion monitoring mode was used for enhanced sensitivity and selectivity. This method was sufficiently sensitive to detect part-per-trillion levels of volatile plant compounds in field ambient air. Laboratory and field evaluation revealed that the method presented high precision and accuracy. Field studies indicated that the background odor of tea plantations contained some common volatile plant compounds, such as (Z)-3-hexenol, methyl salicylate, and (E)-ocimene, at concentrations ranging from 1 to 3400 ng m(-3). In addition, the background odor in summer was more abundant in quality and quantity than in autumn. Relative to previous methods, the TD-GC-MS method is more sensitive, permitting accurate qualitative and quantitative measurements of volatile plant compounds in field ambient air.

Formation and evolution of molecular products in α-pinene secondary organic aerosol.

PubMed

Zhang, Xuan; McVay, Renee C; Huang, Dan D; Dalleska, Nathan F; Aumont, Bernard; Flagan, Richard C; Seinfeld, John H

2015-11-17

Much of our understanding of atmospheric secondary organic aerosol (SOA) formation from volatile organic compounds derives from laboratory chamber measurements, including mass yield and elemental composition. These measurements alone are insufficient to identify the chemical mechanisms of SOA production. We present here a comprehensive dataset on the molecular identity, abundance, and kinetics of α-pinene SOA, a canonical system that has received much attention owing to its importance as an organic aerosol source in the pristine atmosphere. Identified organic species account for ∼58-72% of the α-pinene SOA mass, and are characterized as semivolatile/low-volatility monomers and extremely low volatility dimers, which exhibit comparable oxidation states yet different functionalities. Features of the α-pinene SOA formation process are revealed for the first time, to our knowledge, from the dynamics of individual particle-phase components. Although monomeric products dominate the overall aerosol mass, rapid production of dimers plays a key role in initiating particle growth. Continuous production of monomers is observed after the parent α-pinene is consumed, which cannot be explained solely by gas-phase photochemical production. Additionally, distinct responses of monomers and dimers to α-pinene oxidation by ozone vs. hydroxyl radicals, temperature, and relative humidity are observed. Gas-phase radical combination reactions together with condensed phase rearrangement of labile molecules potentially explain the newly characterized SOA features, thereby opening up further avenues for understanding formation and evolution mechanisms of α-pinene SOA.

75 FR 57412 - Approval and Promulgation of Implementation Plans Alabama: Volatile Organic Compounds

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-21

...] Approval and Promulgation of Implementation Plans Alabama: Volatile Organic Compounds AGENCY: Environmental... compounds'' (VOCs) found at Alabama Administrative Code section 335-3-1-.02(gggg). Specifically, the revision would add two compounds (propylene carbonate and dimethyl carbonate) to the list of those excluded...

Serpentinization and Synthesis: Can abiotic and biotic non-volatile organic molecules be identified in the subsurface of the Atlantis Massif?

NASA Astrophysics Data System (ADS)

Hickok, K.; Nguyen, T.; Orcutt, B.; Fruh-Green, G. L.; Wanamaker, E.; Lang, S. Q.

2016-12-01

The high concentrations of hydrogen created during serpentinization can promote the formation of abiotic organic carbon molecules such as methane, formate, short chain hydrocarbons and, in laboratory experiments, larger molecules containing up to 32 carbon atoms. Subsurface archaeal and bacterial communities can use these reduced compounds for metabolic energy. International Ocean Discovery Project Expedition 357 drilled into the Atlantis Massif with the goals of investigating carbon cycling and the presence of life in a zone of active serpentinization. The expedition recovered multiple rock lithologies including gabbros, basalts, carbonate sands, and serpentinites. A subset of these samples are being analyzed to determine if non-volatile organic molecules are produced abiotically in serpentinizing environments and to identify `hot spots' of microbial life in the subsurface. Rock samples of contrasting representative lithologies are being analyzed for the presence of n-alkanes and fatty acids. Preliminary results have so far indicated the presence of alkanes in some samples. The isotopic (13C, 2H) characteristics of these compounds are being compared to a suite of oils, greases, and drilling fluids used during sample collection to distinguish in situ abiotic and biotic signatures from contaminant compounds. Other initial results have shown the efficacy of various sample-handling procedures designed to reduce surface contamination. This study will contribute to the overall understanding of the role serpentinization plays in the global carbon cycle and its implications for pre-biotic chemistry.

Formation of volatile compounds in kefir made of goat and sheep milk with high polyunsaturated fatty acid content.

PubMed

Cais-Sokolińska, D; Wójtowski, J; Pikul, J; Danków, R; Majcher, M; Teichert, J; Bagnicka, E

2015-10-01

This article explored the formation of volatile compounds during the production of kefir from goat and sheep milks with high polyunsaturated fatty acids (PUFA) as a result of feeding animals forage supplemented with maize dried distillers grains with solubles (DDGS). The increased PUFA content of the goat and sheep milks resulted in significant changes to the fermentation process. In particular, apart from an increase in the time taken to ferment sheep milk, fermentation yielded less 2,3-butanedione. The highest quantities of this compound were assayed in kefir produced from goat milk with an increased content of PUFA. An increase of PUFA significantly elevated ethanal synthesis during lactose-alcohol fermentation of sheep milk. Neither the origin of milk (sheep or goat) nor the level of PUFA had any statistical effect on the amount of ethanal assayed during the fermentation of milk and within the finished product. The proportion of l(+)-lactic acid was higher in kefirs produced using goat milk compared with sheep milk and did not depend on the content of PUFA in milk fat. The content of PUFA had a significant effect on the aroma profile of the resulting kefirs. An increase in PUFA content resulted in the loss of whey aroma in goat milk kefirs and the animal odor in sheep milk kefirs, and a creamy aroma became more prevalent in kefirs made from sheep milk. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Emission sources of non-methane volatile organic compounds (NMVOCs) and their contribution to photochemical ozone (O3) formation at an urban atmosphere in western India.

NASA Astrophysics Data System (ADS)

Yadav, R.; Sahu, L. K.; Tripathi, N.; Pal, D.

2017-12-01

Atmospheric non-methane volatile organic compounds (NMVOCs) were measured at a sampling site in Udaipur city of western India during 2015 to recognize their pollution levels, variation characteristics, sources and photochemical reactivity. The samples were analyzed for NMVOCs using a Gas Chromatograph equipped with Flame Ionization Detector (GC/FID) and Thermal Desorption (TD) system. The main focus on understand the sources responsible for NMVOC emissions, and evaluating the role of the identified sources towards ozone formation. Hourly variations of various NMVOC species indicate that VOCs mixing ratios were influenced by photochemical removal with OH radicals for reactive species, secondary formation for oxygenated VOCs. In general, higher mixing ratios were observed during winter/pre-monsoon and lower levels during the monsoon season due to the seasonal change in meteorological, transport path of air parcel and boundary layer conditions. The high levels of propane (C3H8) and butane (C4H10) show the dominance of LPG over the study location. The correlation coefficients of typical NMVOC pairs (ethylene/propylene, propylene/isoprene, and ethane/propane) depicted that vehicular emission and natural gas leakages were important sources for atmospheric hydrocarbons in Udaipur. Based on the annual data, PMF analysis suggest the source factors namely biomass burning/ bio-fuel, automobile exhaust, Industrial/ natural gas/power plant emissions, petrol/Diesel, gasoline evaporation, and use of liquid petroleum gas (LPG) contribute to NMVOCs loading. The propylene-equivalent and ozone formation potential of NMVOCs have also been calculated in order to find out their OH reactivity and contribution to the photochemical ozone formation.

GCMS investigation of volatile compounds in green coffee affected by potato taste defect and the Antestia bug.

PubMed

Jackels, Susan C; Marshall, Eric E; Omaiye, Angelica G; Gianan, Robert L; Lee, Fabrice T; Jackels, Charles F

2014-10-22

Potato taste defect (PTD) is a flavor defect in East African coffee associated with Antestiopsis orbitalis feeding and 3-isopropyl-2-methoxypyrazine (IPMP) in the coffee. To elucidate the manifestation of PTD, surface and interior volatile compounds of PTD and non-PTD green coffees were sampled by headspace solid phase microextraction and analyzed by gas chromatography mass spectrometry. Principal component analysis of the chromatographic data revealed a profile of surface volatiles distinguishing PTD from non-PTD coffees dominated by tridecane, dodecane, and tetradecane. While not detected in surface volatiles, IPMP was found in interior volatiles of PTD coffee. Desiccated antestia bugs were analyzed by GCMS, revealing that the three most prevalent volatiles were tridecane, dodecane, and tetradecane, as was found in the surface profile PTD coffee. Coffee having visible insect damage exhibited both a PTD surface volatile profile and IPMP in interior volatiles, supporting the hypothesis linking antestia bug feeding activity with PTD profile compounds on the surface and IPMP in the interior of the beans.

Cloud processing of organic compounds: Secondary organic aerosol and nitrosamine formation

NASA Astrophysics Data System (ADS)

Hutchings, James W., III

Cloud processing of atmospheric organic compounds has been investigated through field studies, laboratory experiments, and numerical modeling. Observational cloud chemistry studies were performed in northern Arizona and fog studies in central Pennsylvania. At both locations, the cloud and fogs showed low acidity due to neutralization by soil dust components (Arizona) and ammonia (Pennsylvania). The field observations showed substantial concentrations (20-5500 ng•L -1) of volatile organic compounds (VOC) in the cloud droplets. The potential generation of secondary organic aerosol mass through the processing of these anthropogenic VOCs was investigated through laboratory and modeling studies. Under simulated atmospheric conditions, in idealized solutions, benzene, toluene, ethylbenzene, and xylene (BTEX) degraded quickly in the aqueous phase with half lives of approximately three hours. The degradation process yielded less volatile products which would contribute to new aerosol mass upon cloud evaporation. However, when realistic cloud solutions containing natural organic matter were used in the experiments, the reaction kinetics decreased with increasing organic carbon content, resulting in half lives of approximately 7 hours. The secondary organic aerosol (SUA) mass formation potential of cloud processing of BTEX was evaluated. SOA mass formation by cloud processing of BTEX, while strongly dependent on the atmospheric conditions, could contribute up to 9% of the ambient atmospheric aerosol mass, although typically ˜1% appears realistic. Field observations also showed the occurrence of N-nitrosodimethylamine (NDMA), a potent carcinogen, in fogs and clouds (100-340 ng•L -1). Laboratory studies were conducted to investigate the formation of NDMA from nitrous acid and dimethylamine in the homogeneous aqueous phase within cloud droplets. While NDMA was produced in the cloud droplets, the low yields (<1%) observed could not explain observational concentrations. Therefore heterogeneous or gaseous formation of NDMA with partitioning to droplet must be the source of aqueous NDMA. Box-model calculations tended to demonstrate a predominance of a gas phase formation mechanism followed by partitioning into the cloud droplets. The calculations were consistent with field measurements of gaseous and aqueous NDMA concentrations. Measurements and model calculations showed that while NDMA is eventually photolyzed, it might persist in the atmosphere for hours.

Comparison of methods for determining volatile compounds in cheese, milk, and whey powder

USDA-ARS?s Scientific Manuscript database

Solid phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) are commonly used for qualitative and quantitative analysis of volatile compounds in various dairy products, but selecting the proper procedures presents challenges. Heat is applied to drive volatiles from the samp...

Data on volatile compounds in fermented materials used for salmon fish sauce production.

PubMed

Nakano, Mitsutoshi; Sagane, Yoshimasa; Koizumi, Ryosuke; Nakazawa, Yozo; Yamazaki, Masao; Watanabe, Toshihiro; Takano, Katsumi; Sato, Hiroaki

2018-02-01

This article describes the analysis of volatile compounds in fermented materials used for salmon fish sauce production via gas chromatography/mass spectrometry (GC/MS). Ten types of fish sauces were produced from raw salmon materials, including various proportions of flesh, viscera, inedible portion (heads, fins, and backbones), and soft roe, by mixing them with salt and allowing them to ferment for up to three months. The volatile compounds were captured by a solid-phase microextraction method and then applied to GC/MS for separation and identification of the compounds in the fish sauce products. The number of volatile compounds identified in the starting materials varied from 15 to 29 depending on the ingredients. The number of compounds in the final fish sauce products was reduced by 3.4-94.7% of that in the original material. The retention times and names of the identified compounds, as well as their relative peak areas, are provided in a Microsoft Excel Worksheet.

A process for producing lignin and volatile compounds from hydrolysis liquor.

PubMed

Khazraie, Tooran; Zhang, Yiqian; Tarasov, Dmitry; Gao, Weijue; Price, Jacquelyn; DeMartini, Nikolai; Hupa, Leena; Fatehi, Pedram

2017-01-01

Hot water hydrolysis process is commercially applied for treating wood chips prior to pulping or wood pellet production, while it produces hydrolysis liquor as a by-product. Since the hydrolysis liquor is dilute, the production of value-added materials from it would be challenging. In this study, acidification was proposed as a viable method to extract (1) furfural and acetic acid from hot water hydrolysis liquor and (2) lignin compounds from the liquor. The thermal properties of the precipitates made from the acidification of hydrolysis liquor confirmed the volatile characteristics of precipitates. Membrane dialysis was effective in removing inorganic salts associated with lignin compounds. The purified lignin compounds had a glass transition temperature (Tg) of 180-190 °C, and were thermally stable. The results confirmed that lignin compounds present in hot water hydrolysis liquor had different characteristics. The acidification of hydrolysis liquor primarily removed the volatile compounds from hydrolysis liquor. Based on these results, a process for producing purified lignin and precipitates of volatile compounds was proposed.

Real-Time and Delayed Analysis of Tree and Shrub Cores as Indicators of Subsurface Volatile Organic Compound Contamination, Durham Meadows Superfund Site, Durham, Connecticut, August 29, 2006

USGS Publications Warehouse

Vroblesky, Don A.; Willey, Richard E.; Clifford, Scott; Murphy, James J.

2008-01-01

This study examined volatile organic compound concentrations in cores from trees and shrubs for use as indicators of vadose-zone contamination or potential vapor intrusion by volatile organic compounds into buildings at the Durham Meadows Superfund Site, Durham, Connecticut. The study used both (1) real-time tree- and shrub-core analysis, which involved field heating the core samples for 5 to 10 minutes prior to field analysis, and (2) delayed analysis, which involved allowing the gases in the cores to equilibrate with the headspace gas in the sample vials unheated for 1 to 2 days prior to analysis. General correspondence was found between the two approaches, indicating that preheating and field analysis of vegetation cores is a viable approach to real-time monitoring of subsurface volatile organic compounds. In most cases, volatile organic compounds in cores from trees and shrubs at the Merriam Manufacturing Company property showed a general correspondence to the distribution of volatile organic compounds detected in a soil-gas survey, despite the fact that most of the soil-gas survey data in close proximity to the relevant trees were collected about 3 years prior to the tree-core collection. Most of the trees cored at the Durham Meadows Superfund Site, outside of the Merriam Manufacturing Company property, contained no volatile organic compounds and were in areas where indoor air sampling and soil-gas sampling showed little or no volatile organic compound concentrations. An exception was tree DM11, which contained barely detectable concentrations of trichloroethene near a house where previous investigations found low concentrations of trichloroethene (0.13 to 1.2 parts per billion by volume) in indoor air and 7.7 micrograms per liter of trichloroethene in the ground water. The barely detectable concentration of trichloroethene in tree DM11 and the lack of volatile organic compound detection in nearby tree DM10 (adjacent to the well having 7.7 micrograms of trichloroethene) may be attributable to the relatively large depth to water (17.6 feet), the relatively low soil-vapor trichloroethene concentration, and the large amount of rainfall during and preceding the tree-coring event. The data indicate that real-time and delayed analyses of tree cores are viable approaches to examining subsurface volatile organic compound soil-gas or vadose-zone contamination at the Durham Meadows Superfund Site and other similar sites. Thus, the methods may have application for determining the potential for vapor intrusion into buildings.

Unraveling the chemical complexity of biomass burning VOC emissions via H3O+ ToF-CIMS (PTR-ToF): emissions characterization

NASA Astrophysics Data System (ADS)

Koss, A.; Sekimoto, K.; Gilman, J.; Selimovic, V.; Coggon, M.; Zarzana, K. J.; Yuan, B.; Lerner, B. M.; Brown, S. S.; Jimenez, J. L.; Krechmer, J. E.; Warneke, C.; Yokelson, R. J.; De Gouw, J. A.

2017-12-01

Gas-phase biomass burning emissions can include hundreds, if not thousands, of unique volatile and intermediate-volatility organic compounds. It is crucial to know the composition of these emissions to understand secondary organic aerosol formation, ozone formation, and human health effects resulting from fires. However, the composition can vary greatly with fuel type and fire combustion process. During the FIREX 2016 laboratory intensive at the US Forest Service Fire Sciences Laboratory in Missoula, Montana, high-resolution H3O+-CIMS (PTR-ToF) was deployed to characterize VOC emissions. More than 500 ion masses were consistently enhanced in each of 58 fires, which included a wide variety of fuel types representative of the western United States. Using a combination of extensive literature review, H3O+ and NO+ CIMS with GC preseparation, comparison to other instruments, and mass spectral context, we were able to identify the VOC contributors to 90% of the instrument signal. This provides unprecedented chemical detail in high time resolution. We present chemical characteristics of emissions, including OH reactivity and volatility, and highlight areas where better identification is needed.

Aroma composition of shalgam: a traditional Turkish lactic acid fermented beverage.

PubMed

Tanguler, Hasan; Selli, Serkan; Sen, Kemal; Cabaroglu, Turgut; Erten, Huseyin

2017-06-01

Shalgam, a traditional red, cloudy and sour soft beverage, is produced by lactic acid fermentation of black carrot, sourdough, salt, bulgur flour, turnip and adequate water. The present study was designed to characterize the volatile compounds of shalgam obtained from different methods. The aroma compounds of shalgams produced by traditional and direct methods, and addition of Lactic acid bateria (LAB) cultures were examined. Volatile components of shalgam samples were extracted by liquid-liquid extraction technique with pentane/dichloromethane and analyzed by gas chromatography-mass spectrometry (GC-MS). Sixty aroma compounds were identified in shalgam samples including 20 terpenes, 9 esters, 9 alcohols, 5 volatile acids, 6 volatile phenols, 5 lactones, 3 naphthalenes, 2 carbonyl compounds and 1 C13-norisoprenoids. It was found that the aroma profiles of shalgams were quite similar. However, the total volatile content of the shalgam samples increased with addition of Lb. plantarum .

Composition of the water-soluble fraction of different cheeses.

PubMed

Taborda, Gonzalo; Molina, Elena; Martínez-Castro, Isabel; Ramos, Mercedes; Amigo, Lourdes

2003-01-01

Volatile and nonvolatile compounds present in the water-soluble fraction (WSF) and water-soluble fraction with molecular weight lower than 1000 Da (WSF < 1000 Da) of six Spanish cheeses, Cabrales, Idiazábal, Mahón, Manchego, Roncal, and a goat's milk cheese, were analyzed. Different nitrogen fractions (determined by Kjeldahl method), caseins (by capillary electrophoresis), peptides and amino acids (by HPLC), and volatile components (by dynamic headspace coupled to GC-MS) as well as mineral content in the cheese fractions were analyzed and compared. The different nitrogen and volatile compounds identified in the WSF were characteristic of each cheese variety. Cabrales cheese displayed the highest content of free amino acids and the highest quantity and variety of volatile compounds. The WSF < 1000 Da fraction was less representative, especially for volatile compounds, as some of the components were lost in the ultrafiltration. Alcohols were better recovered than ketones and esters.

Effect of edible coating on the aromatic attributes of roasted coffee beans.

PubMed

Rattan, Supriya; Parande, A K; Ramalakshmi, K; Nagaraju, V D

2015-09-01

Coffee is known throughout the world for its distinct aroma and flavour which results from a number of volatile compounds present in it. It is very difficult to arrest the aromatic compounds once the roasting process is complete and it becomes even more challenging to store the beans for a longer time with the retained volatiles as these compounds are easily lost during industrialized processing such as the grinding of roasted coffee beans and storage of ground coffee. Thus, an attempt was made to minimise the loss of volatile from roasted coffee beans by coating with Carboxymethyl cellulose (CMC), Hydroxypropylmethyl cellulose (HPMC) and Whey protein concentrate. Coffee volatiles were analysed by Gas chromatography and 14 major compounds were identified and compared in this study. Results showed an increase in the relative area of major volatile compounds in coated roasted coffee beans when compared with unroasted coffee beans for consecutive two months. Moreover, effect of coating on textural properties and non-volatiles were also analysed. The results have indicated that edible coatings preserve the sensory properties of roasted coffee beans for a longer shelf life and cellulose derivatives, as an edible coating, exhibited the best protecting effect on roasted coffee beans.

Possible role of plant volatiles in tolerance against huanglongbing in citrus

PubMed Central

Hijaz, Faraj; Nehela, Yasser; Killiny, Nabil

2016-01-01

abstract Volatile organic compounds (VOC) play an important role in protecting plants from insect and pathogen attack. In this study, we investigated the leaf volatile profiles of 14 citrus varieties. The VOC in citrus leaves were extracted with n-hexane and analyzed using gas chromatography-mass spectrometry (GC-MS). Overall, 4six volatile compounds were identified in the n-hexane extract from citrus leaves. Most of the detected compounds belonged to 3 main groups (monoterpenes, sesquiterpenes, and aliphatic aldehydes). Principle component analysis was used to examine the relative distribution of the studied varieties to each other. Interestingly, volatile profiles of varieties that are tolerant to Candidatus Liberibacter asiaticus (CLas) were different from those of the susceptible ones. Tolerant and moderately-tolerant cultivars contained relatively higher amounts of volatiles than susceptible varieties. In addition, tolerant varieties were also higher in specific compounds which are known for their antimicrobial activities. These compounds include Aldehydes (undecanal, neral, geranial, and citronellal) and some monoterpenes such as linalool, d-limonene, myrcene, α- and β- phellandrene. In addition, some sesquiterpene compounds including t-caryophellene, γ-elemene, β-elemene, germacrene D, and geranyl acetate were higher in tolerant and moderately tolerant cultivars. Severinia buxifolia which is known for its tolerance to CLas and many other pathogens contained higher levels of santalenes and coumarins. Our results indicated that citrus leaf volatiles might play a role in citrus tolerance to CLas. The results of this study may help in understanding of the mechanism of citrus tolerance against CLas. PMID:26829496

Possible role of plant volatiles in tolerance against huanglongbing in citrus.

PubMed

Hijaz, Faraj; Nehela, Yasser; Killiny, Nabil

2016-01-01

Volatile organic compounds (VOC) play an important role in protecting plants from insect and pathogen attack. In this study, we investigated the leaf volatile profiles of 14 citrus varieties. The VOC in citrus leaves were extracted with n-hexane and analyzed using gas chromatography-mass spectrometry (GC-MS). Overall, 4six volatile compounds were identified in the n-hexane extract from citrus leaves. Most of the detected compounds belonged to 3 main groups (monoterpenes, sesquiterpenes, and aliphatic aldehydes). Principle component analysis was used to examine the relative distribution of the studied varieties to each other. Interestingly, volatile profiles of varieties that are tolerant to Candidatus Liberibacter asiaticus (CLas) were different from those of the susceptible ones. Tolerant and moderately-tolerant cultivars contained relatively higher amounts of volatiles than susceptible varieties. In addition, tolerant varieties were also higher in specific compounds which are known for their antimicrobial activities. These compounds include Aldehydes (undecanal, neral, geranial, and citronellal) and some monoterpenes such as linalool, d-limonene, myrcene, α- and β- phellandrene. In addition, some sesquiterpene compounds including t-caryophellene, γ-elemene, β-elemene, germacrene D, and geranyl acetate were higher in tolerant and moderately tolerant cultivars. Severinia buxifolia which is known for its tolerance to CLas and many other pathogens contained higher levels of santalenes and coumarins. Our results indicated that citrus leaf volatiles might play a role in citrus tolerance to CLas. The results of this study may help in understanding of the mechanism of citrus tolerance against CLas.

[Study on two preparation methods for beta-CD inclusion compound of four traditional Chinese medicine volatile oils].

PubMed

Li, Hailiang; Cui, Xiaoli; Tong, Yan; Gong, Muxin

2012-04-01

To compare inclusion effects and process conditions of two preparation methods-colloid mill and saturated solution-for beta-CD inclusion compound of four traditional Chinese medicine volatile oils and study the relationship between each process condition and volatile oil physical properties and the regularity of selective inclusion of volatile oil components. Volatile oils from Nardostachyos Radix et Rhizoma, Amomi Fructus, Zingiberis Rhizoma and Angelicaesinensis Radix were prepared using two methods in the orthogonal test. These inclusion compounds by optimized processes were assessed and compared by such methods as TLC, IR and scanning electron microscope. Inclusion oils were extracted by steam distillation, and the components found before and after inclusion were analyzed by GC-MS. Analysis showed that new inclusion compounds, but inclusion compounds prepared by the two processes had differences to some extent. The colloid mill method showed a better inclusion effect than the saturated solution method, indicating that their process conditions had relations with volatile oil physical properties. There were differences in the inclusion selectivity of components between each other. The colloid mill method for inclusion preparation is more suitable for industrial requirements. To prepare volatile oil inclusion compounds with heavy gravity and high refractive index, the colloid mill method needs longer time and more water, while the saturated solution method requires higher temperature and more beta-cyclodextrin. The inclusion complex prepared with the colloid mill method contains extended molecular weight chemical composition, but the kinds of components are reduced.

Real-Time Mass Spectrometry Monitoring of Oak Wood Toasting: Elucidating Aroma Development Relevant to Oak-aged Wine Quality

NASA Astrophysics Data System (ADS)

Farrell, Ross R.; Wellinger, Marco; Gloess, Alexia N.; Nichols, David S.; Breadmore, Michael C.; Shellie, Robert A.; Yeretzian, Chahan

2015-11-01

We introduce a real-time method to monitor the evolution of oak aromas during the oak toasting process. French and American oak wood boards were toasted in an oven at three different temperatures, while the process-gas was continuously transferred to the inlet of a proton-transfer-reaction time-of-flight mass spectrometer for online monitoring. Oak wood aroma compounds important for their sensory contribution to oak-aged wine were tentatively identified based on soft ionization and molecular mass. The time-intensity profiles revealed toasting process dynamics illustrating in real-time how different compounds evolve from the oak wood during toasting. Sufficient sensitivity was achieved to observe spikes in volatile concentrations related to cracking phenomena on the oak wood surface. The polysaccharide-derived compounds exhibited similar profiles; whilst for lignin-derived compounds eugenol formation differed from that of vanillin and guaiacol at lower toasting temperatures. Significant generation of oak lactone from precursors was evident at 225 oC. Statistical processing of the real-time aroma data showed similarities and differences between individual oak boards and oak wood sourced from the different origins. This study enriches our understanding of the oak toasting process and demonstrates a new analytical approach for research on wood volatiles.

77 FR 52630 - Approval and Promulgation of Air Quality Implementation Plans; Indiana; Volatile Organic...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-30

... Promulgation of Air Quality Implementation Plans; Indiana; Volatile Organic Compounds; Architectural and... rule that sets emissions limits on the amount of volatile organic compounds in architectural and... period. Any parties interested in commenting on this action should do so at this time. Please note that...

Identification of volatiles in leaves of Alpinia zerumbet 'Variegata' using headspace solid-phase microextraction-gas chromatography-mass spectrometry.

PubMed

Chen, Jian Yan; Ye, Zheng Mei; Huang, Tian Yi; Chen, Xiao Dan; Li, Yong Yu; Wu, Shao Hua

2014-07-01

Alpinia zerumbet 'Variegata' is an aromatic medicinal plant, its foliage producing an intense, unique fragrant odor. This study identified 46 volatile compounds in the leaf tissue of this plant using headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). The major compounds included 1, 8-cineole (43.5%), p-cymene (14.7%), humulene (5.5%), camphor (5.3%), linalool (4.7%), (E)-methyl cinnamate (3.8%), gamma-cadinene (3.3%), humulene oxide II (2.1%) and a-terpineol (1.5%). The majority of the volatiles were terpenoids of which oxygenated monoterpenes were the most abundant, accounting for 57.2% of the total volatiles. Alcohols made up the largest (52.8%) and aldehydes the smallest (0.2%) portions of the volatiles. Many bioactive compounds were present in the volatiles.

Fate of Volatile Organic Compounds in Constructed Wastewater Treatment Wetlands

USGS Publications Warehouse

Keefe, S.H.; Barber, L.B.; Runkel, R.L.; Ryan, J.N.

2004-01-01

The fate of volatile organic compounds was evaluated in a wastewater-dependent constructed wetland near Phoenix, AZ, using field measurements and solute transport modeling. Numerically based volatilization rates were determined using inverse modeling techniques and hydraulic parameters established by sodium bromide tracer experiments. Theoretical volatilization rates were calculated from the two-film method incorporating physicochemical properties and environmental conditions. Additional analyses were conducted using graphically determined volatilization rates based on field measurements. Transport (with first-order removal) simulations were performed using a range of volatilization rates and were evaluated with respect to field concentrations. The inverse and two-film reactive transport simulations demonstrated excellent agreement with measured concentrations for 1,4-dichlorobenzene, tetrachloroethene, dichloromethane, and trichloromethane and fair agreement for dibromochloromethane, bromo-dichloromethane, and toluene. Wetland removal efficiencies from inlet to outlet ranged from 63% to 87% for target compounds.

Identification and Quantification of Oxidoselina-1,3,7(11)-Trien-8-One and Cyanidin-3-Glucoside as One of the Major Volatile and Non-Volatile Low-Molecular-Weight Constituents in Pitanga Pulp.

PubMed

Josino Soares, Denise; Pignitter, Marc; Ehrnhöfer-Ressler, Miriam Margit; Walker, Jessica; Montenegro Brasil, Isabella; Somoza, Veronika

2015-01-01

The pulp of pitanga (Eugenia uniflora L.) is used to prepare pitanga juice. However, there are no reports on the identification and quantification of the main constituents in pitanga pulp. The aim of this study was to identify and quantify the major volatile and non-volatile low-molecular-weight constituents of the pulp. Isolation of volatile compounds was performed by solvent-assisted flavor evaporation technique. Characterization of the main volatile and non-volatile constituents was performed by GC-MS, LC-MS and NMR spectroscopy. For quantitative measurements, the main volatile compound needed to be isolated from pitanga pulp to obtain a commercially not available reference standard. Cyanidin-3-glucoside was determined as one of the most abundant non-volatile pulp compound yielding 53.8% of the sum of the intensities of all ions detected by LC-MS. Quantification of cyanidin-3-glucoside in pitanga pulp resulted in a concentration of 344 ± 66.4 μg/mL corresponding to 688 ± 133 μg/g dried pulp and 530 ± 102 μg/g fruit. For the volatile fraction, oxidoselina-1,3,7(11)-trien-8-one was identified as the main volatile pulp constituent (27.7% of the sum of the intensities of all ions detected by GC-MS), reaching a concentration of 89.0 ± 16.9 μg/mL corresponding to 1.34 ± 0.25 μg/g fresh pulp and 1.03 ± 0.19 μg/g fruit. The results provide quantitative evidence for the occurrence of an anthocyanin and an oxygenated sesquiterpene as one of the major volatile and non-volatile low-molecular-weight compounds in pitanga pulp.

FACTORS CONTROLLING THE EMISSIONS OF MONOTERPENES AND OTHER VOLATILE ORGANIC COMPOUNDS

EPA Science Inventory

Plants contain a number of volatile organic compounds, including isoprene, mono- and sesquiterpenes, alcohols, aldehydes, ketones, and esters. ndividual plant species have unique combinations of these compounds; consequently, the emission pattern for each species is also specific...

40 CFR 59.412 - Incorporations by reference.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) NATIONAL VOLATILE ORGANIC COMPOUND EMISSION STANDARDS FOR CONSUMER AND COMMERCIAL PRODUCTS National Volatile Organic Compound Emission Standards for Architectural Coatings § 59.412 Incorporations by... 19428-2959. (1) ASTM Method C 1315-95, Standard Specification for Liquid Membrane-Forming Compounds...

40 CFR 59.412 - Incorporations by reference.

Code of Federal Regulations, 2013 CFR

2013-07-01

... (CONTINUED) NATIONAL VOLATILE ORGANIC COMPOUND EMISSION STANDARDS FOR CONSUMER AND COMMERCIAL PRODUCTS National Volatile Organic Compound Emission Standards for Architectural Coatings § 59.412 Incorporations by... 19428-2959. (1) ASTM Method C 1315-95, Standard Specification for Liquid Membrane-Forming Compounds...

Improvement of wine aromatic quality using mixtures of lysozyme and dimethyl dicarbonate, with low SO2 concentration.

PubMed

Nieto-Rojo, Rodrigo; Luquin, Asuncion; Ancín-Azpilicueta, Carmen

2015-01-01

The use of sulphur dioxide (SO2) in the treatment of foodstuffs presents some problems as it could lead to pseudo-allergies in some people. The aim of this research work was to study the addition of different preservative mixtures and their influence on the concentration of volatile compounds and sensorial quality in wine. To do so, vinifications were carried out using Garnacha must to which lysozyme, dimethyl dicarbonate (DMDC) and mixtures of these with SO2 were added at different doses (25 and 50 mg l(-1)). The results were compared with a control sample to which only SO2 had been added (50 mg l(-1)). In general, mixtures of SO2 with lysozyme and DMDC favoured the formation of volatile compounds in the wines. Wines obtained from the mixtures of lysozyme and DMDC with 25 mg l(-1) of SO2 had better sensorial quality than the wines obtained with 50 mg l(-1) as the only preservative used.

Fate of 14C-acrylamide in roasted and ground coffee during storage.

PubMed

Baum, Matthias; Böhm, Nadine; Görlitz, Jessica; Lantz, Ingo; Merz, Karl Heinz; Ternité, Rüdiger; Eisenbrand, Gerhard

2008-05-01

Acrylamide (AA) is formed during heating of carbohydrate rich foods in the course of the Maillard reaction. AA has been classified as probably carcinogenic to humans. Storage experiments with roasted coffee have shown that AA levels decrease depending on storage time and temperature. In the present study the fate of AA lost during storage of roasted and ground (R&G) coffee was studied, using 14C-labeled AA as radiotracer. Radiolabel was measured in coffee brew, filter residue, and volatiles. In the brew, total (14)C-label decreased during storage of R&G coffee, while activity in the filter residue built up concomitantly. [2,3-14C]-AA (14C-AA) was the only 14C-related water extractable low molecular compound in the brew detected by radio-HPLC. No formation of volatile 14C-AA-related compounds was detected during storage and coffee brewing. Close to 90% of the radiolabel in the filter residue (spent R&G coffee, spent grounds) remained firmly bound to the matrix, largely resisting extraction by aqueous ammonia, ethyl acetate, chloroform, hexane, and sequential polyenzymatic digest. Furanthiols, which are abundant as aroma components in roasted coffee, have not been found to be involved in the formation of covalent AA adducts and thus do not contribute substantially to the decrease of AA during storage.

Modeling biogenic secondary organic aerosol (BSOA) formation from monoterpene reactions with NO3: A case study of the SOAS campaign using CMAQ

NASA Astrophysics Data System (ADS)

Qin, Momei; Hu, Yongtao; Wang, Xuesong; Vasilakos, Petros; Boyd, Christopher M.; Xu, Lu; Song, Yu; Ng, Nga Lee; Nenes, Athanasios; Russell, Armistead G.

2018-07-01

Monoterpenes react with nitrate radicals (NO3), contributing substantially to nighttime organic aerosol (OA) production. In this study, the role of reactions of monoterpenes + NO3 in forming biogenic secondary organic aerosol (BSOA) was examined using the Community Multiscale Air Quality (CMAQ) model, with extended emission profiles of biogenic volatile organic compounds (BVOCs), species-specific representations of BSOA production from individual monoterpenes and updated aerosol yields for monoterpene + NO3. The model results were compared to detailed measurements from the Southern Oxidants and Aerosol Study (SOAS) at Centreville, Alabama. With the more detailed model, monoterpene-derived BSOA increased by ∼1 μg m-3 at night, accounting for one-third of observed less-oxidized oxygenated OA (LO-OOA), more closely agreeing with observations (lower error, stronger correlation). Implementation of a multigenerational oxidation approach resulted in the model capturing elevated OA episodes. With the aging model, aged semi-volatile organic compounds (ASVOCs) contributed over 60% of the monoterpene-derived BSOA, followed by SOA formation via nitrate radical chemistry, making up to 34% of that formed at night. Among individual monoterpenes, β-pinene and limonene contributed most to the monoterpene-derived BSOA from nighttime reactions.

Corrosion Finishing/Coating Systems for DoD Metallic Substrates Based on Non-Chromate Inhibitors and UV Curable, Zero VOC Materials

DTIC Science & Technology

2010-08-01

Corrosion resistant coatings containing non-chromate inhibitors and no volatile organic compounds were developed and evaluated for DoD applications...Transmission Electron Microscopy TRI – Toxic Release Inventory UV – Ultraviolet UVAs – Ultraviolet Absorbers VOCs – Volatile Organic Compounds XPS – X...containing non-chromate inhibitors and no volatile organic compounds were developed and evaluated for DoD applications. The technical effort

Characterization of volatile aroma compounds from red and black rice bran.

PubMed

Sukhonthara, Sukhontha; Theerakulkait, Chockchai; Miyazawa, Mitsuo

2009-01-01

The volatile oils from red and black rice bran were obtained by hydrodistillation using diethyl ester and the components of that oil were analyzed by capillary GC-MS. The volatile components of essential oil from red and black rice bran were analyzed by GC and GC-MS. One hundred twenty-nine (129) of volatile compounds were identified in red and black rice bran. Myristic acid, nonanal, (E)-beta-ocimene and 6, 10, 14-trimethyl-2-pentadecanone were main compounds in red rice bran, whereas myristic acid, nonanal, caproic acid, pentadecanal and pelargonic acid were main compounds in black rice bran. Guaiacol, presented at 0.81 mg/100 g in black rice bran, is responsible for the characteristic component in black rice.

A comprehensive screen for volatile organic compounds in biological fluids.

PubMed

Sharp, M E

2001-10-01

A headspace gas chromatographic (GC) screen for common volatile organic compounds in biological fluids is reported. Common GC phases, DB-1 and DB-WAX, with split injection provide separation and identification of more than 40 compounds in a single 20-min run. In addition, this method easily accommodates quantitation. The screen detects commonly encountered volatile compounds at levels below 4 mg%. A control mixture, providing qualitative and semiquantitative information, is described. For comparison, elution of the volatiles on a specialty phase, DB-624, is reported. This method is an expansion and modification of a screen that had been used for more than 20 years. During its first year of use, the expanded screen has proven to be advantageous in routine forensic casework.

Known and Newly Identified Semi-Volatile Organic Compounds from Biomass Burning in Amazonia: Variability and Relationship to Aerosol Physical Properties

NASA Astrophysics Data System (ADS)

Wernis, R. A.; Yee, L.; Isaacman-VanWertz, G. A.; Kreisberg, N. M.; de Sá, S. S.; Liu, Y.; Martin, S. T.; Alexander, M. L. L.; Palm, B. B.; Hu, W.; Campuzano-Jost, P.; Day, D. A.; Jimenez, J. L.; Artaxo, P.; Viegas, J.; Manzi, A. O.; Souza, R. A. F. D.; Hering, S. V.; Goldstein, A. H.

2016-12-01

Aerosols are a source of great uncertainty in radiative forcing predictions and have poorly understood impacts on human health. In many environments, biomass burning contributes a significant source of primary aerosol as well as reactive gas-phase precursors that can form secondary organic aerosol (SOA). One class of these precursors, semi-volatile organic compounds (SVOCs), has been shown to have a large contribution to the amount of SOA formed from fire emissions. At present, SVOC emissions from biomass burning are poorly constrained and understanding their contributions to SOA formation is an important research challenge. In the Amazonian dry season, biomass burning is a major source of gases and aerosols reducing regional air quality. As part of the GoAmazon 2014/5 field campaign, we deployed the Semi-Volatile Thermal desorption Aerosol Gas Chromatograph (SV-TAG) instrument at the rural T3 site, 60 km to the west of Manaus, Brazil to measure hourly concentrations of SVOCs in the gas and particle phases. This comprehensive technique detects thousands of compounds, enabling the discovery of previously unidentified compounds. In this work we explore compounds for which a correlation with well-known biomass burning tracers is observed to discover the identities of new markers. We discuss contributions to the total organic aerosol from over 30 well-known, rarely reported and newly identified biomass burning markers. We examine the relationship between biomass burning aerosol composition and aerosol physical properties as measured at the T3 site. Additionally, we report gas-particle partitioning of all identified compounds with comparison to theoretical predictions. We find that the commonly used biomass burning tracer levoglucosan existed entirely in the particle phase and contributed 0.6% and 0.3% of total organic aerosol mass in the dry and wet seasons, respectively.

Aroma Volatile Compounds from Two Fresh Pineapple Varieties in China

PubMed Central

Zheng, Liang-Yong; Sun, Guang-Ming; Liu, Yu-Ge; Lv, Ling-Ling; Yang, Wen-Xiu; Zhao, Wei-Feng; Wei, Chang-Bin

2012-01-01

Volatile compounds from two pineapples varieties (Tainong No.4 and No.6) were isolated by headspace solid phase microextraction (HS-SPME) and identified and quantified by gas chromatography-mass spectrometry (GC/MS). In the Tainong No. 4 and No. 6 pineapples, a total of 11 and 28 volatile compounds were identified according to their retention time on capillary columns and their mass spectra, and quantified with total concentrations of 1080.44 μg·kg−1 and 380.66 μg·kg−1 in the Tainong No.4 and No. 6 pineapples, respectively. The odor active values (OAVs) of volatile compounds from pineapples were also calculated. According to the OAVs, four compounds were defined as the characteristic aroma compounds for the Tainong No. 4 pineapple, including furaneol, 3-(methylthio)propanoic acid methyl ester, 3-(methylthio)propanoic acid ethyl ester and δ-octalactone. The OAVs of five compounds including ethyl-2-methylbutyrate, methyl-2-methylbutyrate, 3-(methylthio)propanoic acid ethyl ester, ethyl hexanoate and decanal were considered to be the characteristic aroma compounds for the Tainong No. 6 pineapple. PMID:22837701

Volatile compounds of dry beans (Phaseolus vulgaris L.).

PubMed

Oomah, B Dave; Liang, Lisa S Y; Balasubramanian, Parthiba

2007-12-01

Volatile compounds of uncooked dry bean (Phaseolus vulgaris L.) cultivars representing three market classes (black, dark red kidney and pinto) grown in 2005 were isolated with headspace solid phase microextraction (HS-SPME), and analyzed with gas chromatography mass spectrometry (GC-MS). A total of 62 volatiles consisting of aromatic hydrocarbons, aldehydes, alkanes, alcohols and ketones represented on average 62, 38, 21, 12, and 9 x 10(6) total area counts, respectively. Bean cultivars differed in abundance and profile of volatiles. The combination of 18 compounds comprising a common profile explained 79% of the variance among cultivars based on principal component analysis (PCA). The SPME technique proved to be a rapid and effective method for routine evaluation of dry bean volatile profile.

PhMYB4 fine-tunes the floral volatile signature of Petunia x hybrida through PhC4H.

PubMed

Colquhoun, Thomas A; Kim, Joo Young; Wedde, Ashlyn E; Levin, Laura A; Schmitt, Kyle C; Schuurink, Robert C; Clark, David G

2011-01-01

In Petunia × hybrida cv 'Mitchell Diploid' (MD), floral volatile benzenoid/phenylpropanoid (FVBP) biosynthesis is controlled spatially, developmentally, and daily at molecular, metabolic, and biochemical levels. Multiple genes have been shown to encode proteins that either directly catalyse a biochemical reaction yielding FVBP compounds or are involved in metabolite flux prior to the formation of FVBP compounds. It was hypothesized that multiple transcription factors are involved in the precise regulation of all necessary genes, resulting in the specific volatile signature of MD flowers. After acquiring all available petunia transcript sequences with homology to Arabidopsis thaliana R2R3-MYB transcription factors, PhMYB4 (named for its close identity to AtMYB4) was identified, cloned, and characterized. PhMYB4 transcripts accumulate to relatively high levels in floral tissues at anthesis and throughout open flower stages, which coincides with the spatial and developmental distribution of FVBP production and emission. Upon RNAi suppression of PhMYB4 (ir-PhMYB4) both petunia cinnamate-4-hydroxylase (PhC4H1 and PhC4H2) gene transcript levels were significantly increased. In addition, ir-PhMYB4 plants emit higher levels of FVBP compounds derived from p-coumaric acid (isoeugenol and eugenol) compared with MD. Together, these results indicate that PhMYB4 functions in the repression of C4H transcription, indirectly controlling the balance of FVBP production in petunia floral tissue (i.e. fine-tunes).

Identification of odor volatile compounds and deodorization of Paphia undulata enzymatic hydrolysate

NASA Astrophysics Data System (ADS)

Chen, Deke; Chen, Xin; Chen, Hua; Cai, Bingna; Wan, Peng; Zhu, Xiaolian; Sun, Han; Sun, Huili; Pan, Jianyu

2016-12-01

Unfavorable fishy odour is an inevitable problem in aquatic products. In the present study, headspace solid-phase microextraction gas chromatography mass spectrometry (HS-SPME-GC-MS) analysis of volatiles from untreated samples and three deodorized samples (under the optimal conditions) of Paphia undulata enzymatic hydrolysate revealed that the compounds contributing to the distinctive odor were 1-octen-3-ol, n-hexanal, n-heptanal, 2,4-heptadienal, and 2,4-decadienal, whereas n-pentanal, n-octanal, n-octanol, benzaldehyde, 2-ethylfuran and 2-pentylfuran were the main contributors to the aromatic flavor. The deodorizing effects of activated carbon (AC) adsorption, yeast extract (YE) masking and tea polyphenol (TP) treatment on a P. undulata enzymatic hydrolysate were investigated using orthogonal experiments with sensory evaluation as the index. The following optimized deodorization conditions were obtained: AC adsorption (35 mg mL-1, 80°C, 40 min), YE masking (7 mg mL-1, 45°C, 30 min) and TP treatment (0.4 mg mL-1, 40°C, 50 min). AC adsorption effectively removed off-flavor volatile aldehydes and ketones. YE masking modified the odor profile by increasing the relative contents of aromatic compounds and decreasing the relative contents of aldehydes and ketones. The TP treatment was not effective in reducing the odor score, but it significantly reduced the relative content of aldehydes while increasing that of alkanes. It is also notable that TP effectively suppressed trimethylamine (TMA) formation in a P. undulate hydrolysate solution for a period of 72 h.

Analysis of flavor compounds by GC/MS after liquid-liquid extraction from fruit juices

NASA Astrophysics Data System (ADS)

Tuşa, F. D.; Moldovan, Z.; Schmutzer, G.; Magdaş, D. A.; Dehelean, A.; Vlassa, M.

2012-02-01

In this work we describe a rapid method for analysis of volatile profiles of several commercial fruit juices using GC/MS instrument after liquid-liquid extraction. Volatile flavor compounds have been identified based on mass spectrum obtained in EI mode. This method allows to analyses a wide range of flavor compounds (esters, aldehydes, alcohols, terpenoids) the procedure was rapid, simple and inexpensive. Moreover, by means of volatile compounds it could be possible to distinguish between juices of organic and conventional production and those with flavorings addition. More of 20 compounds were identified and quantified as relative chromatogram area taken on larges ion in mass spectrum.

[Chemical Loss of Volatile Organic Compounds and Its Impact on the Formation of Ozone in Shanghai].

PubMed

Wang, Hong-li

2015-09-01

The spatial characterization of ozone (O3) and its precursors was studied based on the field measurements in urban and rural areas of Shanghai during the summer of 2014. The chemical loss of volatile organic compounds (VOCs) was estimated by the parameterization method. The mixing ratio of VOCs was 20 x 10(-9) in urban area and 17 x 10(-9) in the west rural area during the measurements. The average values of the maximum incremental reactivity were comparable in urban and rural areas, namely 5. 0 mol.mol-1 (O3/VOCs). By contrast, the chemical loss of VOCs was 8. 3 x 10(-9) in west rural area, which was two times as that in urban area. The more chemical loss of VOCs was probably one of the important reasons leading to the higher O3 concentration in west rural area. The regional transport might be important reason of the variation of O3 in the eastern coastal rural area. The chemical loss of VOCs showed good agreement with the local formation of O3 in both urban and rural areas, suggesting a similar efficiency of O3 formation from the chemical loss of VOCs. Among the chemical loss, aromatics and alkenes are the dominant VOC species of the atmospheric chemistry which accounts for more than 90% . The diurnal profile of VOC chemical loss matched well with the production of O3 with one-hour postponement.

Flavoring agents present in a dentifrice can modify volatile sulphur compounds (VSCs) formation in morning bad breath.

PubMed

Peruzzo, Daiane Cristina; Salvador, Sérgio Luis; Sallum, Antonio Wilson; Nogueira-Filho, Getúlio da Rocha

2008-01-01

This study aimed to evaluate the effects of a flavor-containing dentifrice on the formation of volatile sulphur compounds (VSCs) in morning bad breath. A two-step, blinded, crossover, randomized study was carried out in 50 dental students with a healthy periodontium divided into two experimental groups: flavor-containing dentifrice (test) and non-flavor-containing dentifrice (control). The volunteers received the designated dentifrice and a new toothbrush for a 3 X/day brushing regimen for 2 periods of 30 days. A seven-day washout interval was used between the periods. The assessed parameters were: plaque index (PI), gingival index (GI), organoleptic breath scores (ORG), VSC levels (as measured by a portable sulphide monitor) before (H1) and after (H2) cleaning of the tongue, tongue coating (TC) wet weight and BANA test from TC samples. The intra-group analysis showed a decrease in ORG, from 3 to 2, after 30 days for the test group (p < 0.05). The inter-group analysis showed lower values in ORG, H1 and H2 for the test group (p < 0.05). There was no difference between the amount of TC between groups and the presence of flavor also did not interfere in the BANA results between groups (p > 0.05). These findings suggest that a flavor-containing dentifrice seems to prevent VSCs formation in morning bad breath regardless of the amount of TC in periodontally healthy subjects.

Volatile organic compounds in the atmosphere of Mexico City

NASA Astrophysics Data System (ADS)

Garzón, Jessica P.; Huertas, José I.; Magaña, Miguel; Huertas, María E.; Cárdenas, Beatriz; Watanabe, Takuro; Maeda, Tsuneaki; Wakamatsu, Shinji; Blanco, Salvador

2015-10-01

The Mexico City Metropolitan Area (MCMA) is one of the most polluted megacities in North America. Therefore, it is an excellent benchmark city to understand atmospheric chemistry and to implement pilot countermeasures. Air quality in the MCMA is not within acceptable levels, mainly due to high ground levels of ozone (O3). Tropospheric O3 is a secondary pollutant formed from the oxidation of volatile organic compounds (VOCs) in the presence of nitrogen oxides and sunlight. To gain a better understanding of O3 formation in megacities, evaluate the effectiveness of already-implemented countermeasures, and identify new cost-effective alternatives to reduce tropospheric O3 concentrations, researchers and environmental authorities require updated concentrations for a broader range of VOCs. Moreover, in an effort to protect human health and the environment, it is important to understand which VOCs exceed reference safe values or most contribute to O3 formation, as well as to identify the most probable emission sources of those VOCs. In this work, 64 VOCs, including 36 toxic VOCs, were measured at four sites in the MCMA during 2011-2012. VOCs related to liquefied petroleum gas leakages exhibited the highest concentrations. Toxic VOCs with the highest average concentrations were acetone and ethanol. The toxic VOC benzene represented the highest risk to Mexican citizens, and toluene contributed the most to O3 formation. Correlation analysis indicated that the measured VOCs come from vehicular emissions and solvent-related industrial sources.

Volatile organic compounds in pesticide formulations: Methods to estimate ozone formation potential

NASA Astrophysics Data System (ADS)

Zeinali, Mazyar; McConnell, Laura L.; Hapeman, Cathleen J.; Nguyen, Anh; Schmidt, Walter F.; Howard, Cody J.

2011-05-01

The environmental fate and toxicity of active ingredients in pesticide formulations has been investigated for many decades, but relatively little research has been conducted on the fate of pesticide co-formulants or inerts. Some co-formulants are volatile organic compounds (VOCs) and can contribute to ground-level ozone pollution. Effective product assessment methods are required to reduce emissions of the most reactive VOCs. Six emulsifiable concentrate pesticide products were characterized for percent VOC by thermogravimetric analysis (TGA) and gas chromatography-mass spectrometry (GC-MS). TGA estimates exceeded GC-MS by 10-50% in all but one product, indicating that for some products a fraction of active ingredient is released during TGA or that VOC contribution was underestimated by GC-MS. VOC profiles were examined using TGA-Fourier transform infrared (FTIR) evolved gas analysis and were compared to GC-MS results. The TGA-FTIR method worked best for products with the simplest and most volatile formulations, but could be developed into an effective product screening tool. An ozone formation potential ( OFP) for each product was calculated using the chemical composition from GC-MS and published maximum incremental reactivity ( MIR) values. OFP values ranged from 0.1 to 3.1 g ozone g -1 product. A 24-h VOC emission simulation was developed for each product assuming a constant emission rate calculated from an equation relating maximum flux rate to vapor pressure. Results indicate 100% VOC loss for some products within a few hours, while other products containing less volatile components will remain in the field for several days after application. An alternate method to calculate a product OFP was investigated utilizing the fraction of the total mass of each chemical emitted at the end of the 24-h simulation. The ideal assessment approach will include: 1) unambiguous chemical composition information; 2) flexible simulation models to estimate emissions under different management practices; and 3) accurate reactivity predictions.

VOLATILE ORGANIC COMPOUNDS (VOCS) CHAPTER 31.

EPA Science Inventory

The term "volatile organic compounds' (VOCs) was originally coined to refer, as a class, to carbon-containing chemicals that participate in photochemical reactions in the ambient (outdoor) are. The regulatory definition of VOCs used by the U.S. EPA is: Any compound of carbon, ex...

VOLATILE ORGANIC COMPOUNDS MEASURED IN DEARS PASSIVE SAMPLERS

EPA Science Inventory

A suite of 27 volatile organic compounds (VOCs) were monitored in personal exposures, indoors and outdoors of participant's residences, and at a central community site during the DEARS summer 2004 monitoring season. The list of VOCs focused on compounds typically associated with ...

Derived Emission Rates and Photochemical Production Rates of Volatile Organic Compounds (VOCs) Associated with Oil and Natural Gas Operations in the Uintah Basin, UT During a Wintertime Ozone Formation Event

NASA Astrophysics Data System (ADS)

Koss, A.; De Gouw, J. A.; Warneke, C.; Gilman, J.; Lerner, B. M.; Graus, M.; Yuan, B.; Edwards, P. M.; Brown, S. S.; Wild, R. J.; Roberts, J. M.; Bates, T. S.; Quinn, P.

2014-12-01

The Uintah Basin, an oil and natural gas extraction field in Utah, experienced extremely high levels of volatile organic compounds (VOCs) and ozone during the winter of 2013 - up to 100 ppmv carbon and 150 ppbv O3. Here we interpret VOCs measured during an ozone formation event from 31 Jan 2013 to 8 Feb 2013. Ratios of VOCs show strong diurnal cycles and week-long trends. A simple analysis was applied to ratios of aromatic VOCs measured by proton transfer reaction mass spectrometer (PTR-MS) to explain these trends and to estimate emission rates of aromatic VOCs from oil and natural gas extraction, VOC emission ratios relative to benzene, and ambient [OH]. The analysis incorporates the following assumptions: (1) the source composition of emitted VOCs and their emission rates were temporally and spatially constant, and (2) the removal of VOCs was governed by reaction with OH, diurnal profile of which is constrained by measured photolysis rates. The main findings are (1) the emission rate of methane, extrapolated from the emission rate of benzene, is on the same order as an independent estimate from aircraft measurements of methane in 2012, (2) the derived aromatic emission ratios are consistent with source contributions from both oil and gas producing wells, and (3) calculated daily OH concentrations are low, peaking at 1x106 molecules cm-3. The analysis was extended to investigate secondary production of oxygenated VOCs measured by PTR-MS. The analysis is able to explain daytime production, but it does not adequately explain nighttime behavior, which may be affected by complex deposition to snow and ice surfaces. The relative carbon mass of primary and secondary compounds was calculated and compared to observations. At the end of the ozone formation event (day 6), our analysis predicts that secondary (oxidized) VOCs should comprise about 40% of total carbon mass. However, only 12% of these compounds are accounted for by measured oxygenated VOCs and organic aerosol. Additionally, formation rates of measured oxygenated VOCs did not sum to the total primary compound oxidation rate. The disparity is likely due to both incomplete measurements of oxygenated products and VOC loss to deposition.

Darren J. Peterson | NREL

Science.gov Websites

volatile organic compounds at sub-parts-per-million concentration levels," Sensors and Actuators B : Chemical (2006) "The Volatile Organic Compound (VOC) Removal Performance of Desiccant-Based

The Negative Effects of Volatile Sulphur Compounds.

PubMed

Milella, Lisa

2015-01-01

Oral malodor has been studied extensively in humans but not necessarily to the same degree in our veterinary patients where malodor constitutes a significant problem. Breath malodor may originate from the mouth, or from an extra oral source, originating from other organ systems such as gastrointestinal, respiratory, or even systemic disease. Oral malodor is a result of microbial metabolism of exogenous and endogenous proteinaceous substrates leading to the production of compounds such as indole, skatole, tyramine, cadaverine, puterescine, mercaptans, and sulphides. Volatile sulphur compounds have been shown to be the main cause of oral malodor. Although most clients perceive oral malodor to be primarily a cosmetic problem, there is an increasing volume of evidence in human dental literature demonstrating that volatile sulphur compounds produced by bacteria, even at low concentrations, are toxic to tissues and play a role in the pathogenesis of periodontitis. This article reviews the current available literature in human dentistry looking at these negative effects. No veterinary studies have been conducted looking at the negative effects of volatile sulphur compounds specifically, but as this article highlights, we should be aware of the potential negative effects of volatile sulphur compounds and consider this an area of future research.

Analysis of organic volatile flavor compounds in fermented stinky tofu using SPME with different fiber coatings.

PubMed

Liu, Yuping; Miao, Zhiwei; Guan, Wei; Sun, Baoguo

2012-03-26

The organic volatile flavor compounds in fermented stinky tofu (FST) were studied using SPME-GC/MS. A total of 39 volatile compounds were identified, including nine esters, seven alcohols, five alkenes, four sulfides, three heterocycles, three carboxylic acids, three ketones, two aldehydes, one phenol, one amine and one ether. These compounds were determined by MS, and conformed by comparison of the retention times of the separated constituents with those of authentic samples and by comparison of retention indexes (RIs) of separated constituents with the RIs reported in the literature. The predominant volatile compound in FST was indole, followed by dimethyl trisulfide, phenol, dimethyl disulfide and dimethyl tetrasulfide. In order to find a better extraction time, the extraction times was optimized for each type of SPME fiber; the results show that the best extraction time for Carboxen/PDMS is 60 min, for PDMS/DVB 30 min, for DVB/CAR/PDMS 60 min and for PDMS 75 min. Of the four fibers used in this work, Carboxen/PDMS is found to be the most suitable to extract the organic volatile flavor compounds in fermented stinky tofu.

[Study of volatile organic compounds of fresh allium species using headspace combined with surface-enhanced Raman scattering].

PubMed

Si, Min-Zhen; Zhang, De-Qing; Liu, Ren-Ming

2014-09-01

In order to identify volatile organic compounds of fresh plants at room temperature and avoid sample pretreatment and extractions which can be labor intensive, garlic, Chinese chives and scallion were chopped into pieces. Then some of them were placed in the headspace vial and sealed. The gases were drawn from the vial with a syringe and were injected very slowly into Ag colloids for test using R-3000 portable Raman spectrometer. The spectra of volatile organic compounds of allium species, fresh garlic, Chinese chive and shallot plants were successfully.recorded for the first time. For garlic high intensity bands are present at 307, 399, 569, 711, 1,182, 1,287, 1,397 and 1,622 cm(-1). For Chinese chives the high intensity band is present at 672 cm(-1). Low intensity bands are present at 274, 412, 575, 1,185, 1,289, 1,396, 1,618 cm(-1). For shallot high intensity bands are present at 693 cm(-1). Lower intensity bands are present at 372, 888, 1,023 cm(-1). Low intensity bands are present at 1,088, 1,211 and 1,322 cm(-1). The SERS of diallyl disulfide, allyl methyl sulfide and 1-propanethiol in liquid state and gas state were also obtained. The main volatile organic compound of fresh garlic, Chinese chive and shallot are diallyl disulfide, allyl methyl sulfide and 1-propanethiol respectively, and the volatile organic compound of fresh onion, scallion, shallot and chive are all 1-propanethiol. The presented results illustrate that combining headspace and SERS is a powerful tool for volatile organic compound analysis in fresh plants. The volatile organic compound can be detected in fresh plant samples directly and quickly without extraction.

Impact of starter culture, ingredients, and flour type on sourdough bread volatiles as monitored by selected ion flow tube-mass spectrometry.

PubMed

Van Kerrebroeck, Simon; Comasio, Andrea; Harth, Henning; De Vuyst, Luc

2018-04-01

This study deals with the detection of volatile compounds originating from the crumb of breads made with sourdoughs obtained through starter culture-initiated fermentations, which differed in flour type (wheat and teff), ingredients (citrate and malate), fermentation time (24h or 72h), and starter culture strains (homo- and heterofermentative lactic acid bacteria species and acetic acid bacteria species) applied. Therefore, selected ion flow tube-mass spectrometry (SIFT-MS) was used. SIFT-MS is an easy-to-use and promising technique in the field of food and flavor analysis. Volatile compounds of crumb samples from the breads with sourdough were measured and compared with those of reference bread crumb samples. In general, sourdough addition had a positive effect on the concentrations of the volatile compounds measured by SIFT-MS. Furthermore, a trend toward higher concentrations of several volatiles was seen upon the addition of sourdoughs that were fermented up to 72h, compared to the addition of sourdoughs that were fermented for a shorter time. Ethanol was the major volatile compound identified tentatively, next to alcohols, aldehydes, esters, terpenes, and heterocyclic compounds. Also acetoin/ethyl acetate could be identified, but these compounds could not be distinguished. Higher alcohols showed an increase upon the use of sourdough fermented for a long time. High concentrations of acetic acid were found in breads made with Gluconobacter oxydans IMDO A845-initiated sourdough, indicating its potential for sourdough production. Breads made with teff sourdoughs were distinct from wheat-based sourdough breads as to their volatile compound profiles. Copyright © 2018 Elsevier Ltd. All rights reserved.

Influence of harvest maturity and fruit logistics on pineapple (Ananas comosus [L.] Merr.) volatiles assessed by headspace solid phase microextraction and gas chromatography-mass spectrometry (HS-SPME-GC/MS).

PubMed

Steingass, Christof B; Grauwet, Tara; Carle, Reinhold

2014-05-01

Profiling of volatiles from pineapple fruits was performed at four ripening stages using headspace solid-phase microextraction and gas chromatography-mass spectrometry (HS-SPME-GC/MS). In total, 142 volatiles were detected, of which 132 were identified. Multivariate data analysis was carried out to assess the effect of post-harvest storage on volatiles composition of green-ripe sea-freighted pineapple in comparison to air-freighted fruits harvested at full maturity. The latter fruits were characterised by volatiles described as potent odorants in pineapples, such as δ-octalactone, γ-lactones, 1-(E,Z)-3,5-undecatriene and 1,3,5,8-undecatetraene, as well as various methyl esters. In contrast, post-harvest storage of green-ripe sea-freighted fruits resulted in an increased formation of ethyl esters, acetates, acetoxy esters and alcohols, thus allowing the authentication of sea- and air-freighted pineapples, respectively. Particularly, compounds presumably derived from methyl-branched amino acid catabolism were identified in the fruits at later post-harvest stages. In addition, physicochemical traits were determined to characterise the fruit maturity stages. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effect of Inorganic Salts on the Volatility of Organic Acids

PubMed Central

2014-01-01

Particulate phase reactions between organic and inorganic compounds may significantly alter aerosol chemical properties, for example, by suppressing particle volatility. Here, chemical processing upon drying of aerosols comprised of organic (acetic, oxalic, succinic, or citric) acid/monovalent inorganic salt mixtures was assessed by measuring the evaporation of the organic acid molecules from the mixture using a novel approach combining a chemical ionization mass spectrometer coupled with a heated flow tube inlet (TPD-CIMS) with kinetic model calculations. For reference, the volatility, i.e. saturation vapor pressure and vaporization enthalpy, of the pure succinic and oxalic acids was also determined and found to be in agreement with previous literature. Comparison between the kinetic model and experimental data suggests significant particle phase processing forming low-volatility material such as organic salts. The results were similar for both ammonium sulfate and sodium chloride mixtures, and relatively more processing was observed with low initial aerosol organic molar fractions. The magnitude of low-volatility organic material formation at an atmospherically relevant pH range indicates that the observed phenomenon is not only significant in laboratory conditions but is also of direct atmospheric relevance. PMID:25369247

Low-temperature headspace-trap gas chromatography with mass spectrometry for the determination of trace volatile compounds from the fruit of Lycium barbarum L.

PubMed

Chen, Fangjiao; Su, Yue; Zhang, Fang; Guo, Yinlong

2015-02-01

The total saccharides content of Lycium barbarum L. is very high, and a high temperature would result in saccharide decomposition and the emergence of a large amount of water. Moreover, the volatile compounds from the fruit of L. barbarum L. are rather low in concentration. Hence, it is difficult for a conventional headspace method to study the volatile compounds from the fruit of L. barbarum L. Since headspace-trap gas chromatography with mass spectrometry is an excellent method for trace analysis, a headspace-trap gas chromatography with mass spectrometry method based on low-temperature (30°C) enrichment and multiple headspace extraction was developed to explore the volatile compounds from the fruit of L. barbarum L. The headspace of the sample was extracted in 17 cycles at 30°C. Each time, the compounds extracted were concentrated in the trap (Tenax TA and Tenax GR, 1:1). Finally, all the volatile compounds were delivered into the gas chromatograph after thermal desorption. With the method described above, a total of 57 compounds were identified. The identification was completed by mass spectral search, retention index, and accurate mass measurement. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Halitosis in 1999].

PubMed

Meningaud, J P; Bado, F; Favre, E; Bertrand, J C; Guilbert, F

1999-10-01

Bad breath is a major concern to the general population and a source of an important profit industry world wide. Between 50 and 60 per cent of the population suffer from chronic halitosis. This can have consequences for private or professional life. Reasons can imply many specialities: ENT, gastro-enterology, pneumology, hepatology, genetics and psychiatry (a high percentage of the patients who come to the clinic with a primary complaint of halitosis do not have a detectable problem). Nevertheless, 85% are stomatological and are explained by the release of volatile sulfur compounds. These substances have a very offensive odor in very low concentrations. A specialized device called a halimeter is available to measure the volatile sulphur compounds in mouth air but in practice the objective assessment of malodor is still best performed by the organoleptic method. A careful examination can determine the patient's problem in most cases. Initial treatment strategy should focus on the exact cause and on oral hygiene. In addition to the usual recommendations, the daily use of tongue cleaners is very beneficial. Other than etiologic therapy, masking can be achieved by oral care products (mouth rinses, toothpastes, chewing gums) which contain metal ions, especially zinc, that inhibit odor formation because of its affinity to sulphur compounds.

Evaluation of the glycoside hydrolase activity of a Brettanomyces strain on glycosides from sour cherry (Prunus cerasus L.) used in the production of special fruit beers.

PubMed

Daenen, Luk; Sterckx, Femke; Delvaux, Freddy R; Verachtert, Hubert; Derdelinckx, Guy

2008-11-01

The glycoside hydrolase activity of Saccharomyces cerevisiae and Brettanomyces custersii was examined on sour cherry (Prunus cerasus L.) glycosides with bound volatile compounds. Refermentations by the beta-glucosidase-negative S. cerevisiae strains LD25 and LD40 of sour cherry juice-supplemented beer demonstrated only a moderate increase of volatiles. In contrast, the beta-glucosidase-positive B. custersii strain LD72 showed a more pronounced activity towards glycosides with aliphatic alcohols, aromatic compounds and terpenoid alcohols. Important contributors to sour cherry aroma such as benzaldehyde, linalool and eugenol were released during refermentation as shown by analytical tools. A gradually increasing release was observed during refermentations by B. custersii when whole sour cherries, sour cherry pulp or juice were supplemented in the beer. Refermentations with whole sour cherries and with sour cherry stones demonstrated an increased formation of benzyl compounds. Thus, amygdalin was partially hydrolysed, and a large part of the benzaldehyde formed was mainly reduced to benzyl alcohol and some further esterified to benzyl acetate. These findings demonstrate the importance and interesting role of certain Brettanomyces species in the production of fruit lambic beers such as 'Kriek'.

Headspace solid-phase microextraction and gas chromatographic analysis of low-molecular-weight sulfur volatiles with pulsed flame photometric detection and quantification by a stable isotope dilution assay.

PubMed

Ullrich, Sebastian; Neef, Sylvia K; Schmarr, Hans-Georg

2018-02-01

Low-molecular-weight volatile sulfur compounds such as thiols, sulfides, disulfides as well as thioacetates cause a sulfidic off-flavor in wines even at low concentration levels. The proposed analytical method for quantification of these compounds in wine is based on headspace solid-phase microextraction, followed by gas chromatographic analysis with sulfur-specific detection using a pulsed flame photometric detector. Robust quantification was achieved via a stable isotope dilution assay using commercial and synthesized deuterated isotopic standards. The necessary chromatographic separation of analytes and isotopic standards benefits from the inverse isotope effect realized on an apolar polydimethylsiloxane stationary phase of increased film thickness. Interferences with sulfur-specific detection in wine caused by sulfur dioxide were minimized by addition of propanal. The method provides adequate validation data, with good repeatability and limits of detection and quantification. It suits the requirements of wine quality management, allowing the control of oenological treatments to counteract an eventual formation of excessively high concentration of such malodorous compounds. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluation of Mixed Probiotic Starter Cultures Isolated from Kimchi on Physicochemical and Functional Properties, and Volatile Compounds of Fermented Hams.

PubMed

Kim, Young Joo; Park, Sung Yong; Lee, Hong Chul; Yoo, Seung Seok; Oh, Sejong; Kim, Kwang Hyun; Chin, Koo Bok

2016-01-01

The objective of this study was to investigate the effects of mixed starter cultures isolated from kimchi on physicochemical properties, functionality and flavors of fermented ham. Physicochemical properties, microbial counts, shear force, cholesterol contents and volatile compounds of fermented ham were investigated during processing (curing and ripening time). Curing process for 7 d increased saltiness, however, decreased hunter color values (L, a, and b values). Ripening process for 21 d increased most parameters, such as saltiness, color values, weight loss, shear force and cholesterol content due to the drying process. The mixed starter culture had higher lactic acid bacteria than the commercial one. While eight volatile compounds were identified from fermented hams during curing process, total fiftyeight volatile compounds were identified from fermented hams during ripening process. The main volatile compounds were alcohols, esters and furans. However, no differences in volatile compounds were observed between two batches. Fermented hams (batch B) manufactured with probiotic starter culture (LPP) had higher sensory score in texture, color and overall acceptability than counterparts (batch A), while the opposite trend was observed in flavor. Therefore, mixed probiotic starter culture isolated from kimchi might be used as a starter culture to be able to replace with commercial starter culture (LK-30 plus) for the manufacture of fermented ham.

Evaluation of Mixed Probiotic Starter Cultures Isolated from Kimchi on Physicochemical and Functional Properties, and Volatile Compounds of Fermented Hams

PubMed Central

Yoo, Seung Seok

2016-01-01

The objective of this study was to investigate the effects of mixed starter cultures isolated from kimchi on physicochemical properties, functionality and flavors of fermented ham. Physicochemical properties, microbial counts, shear force, cholesterol contents and volatile compounds of fermented ham were investigated during processing (curing and ripening time). Curing process for 7 d increased saltiness, however, decreased hunter color values (L, a, and b values). Ripening process for 21 d increased most parameters, such as saltiness, color values, weight loss, shear force and cholesterol content due to the drying process. The mixed starter culture had higher lactic acid bacteria than the commercial one. While eight volatile compounds were identified from fermented hams during curing process, total fiftyeight volatile compounds were identified from fermented hams during ripening process. The main volatile compounds were alcohols, esters and furans. However, no differences in volatile compounds were observed between two batches. Fermented hams (batch B) manufactured with probiotic starter culture (LPP) had higher sensory score in texture, color and overall acceptability than counterparts (batch A), while the opposite trend was observed in flavor. Therefore, mixed probiotic starter culture isolated from kimchi might be used as a starter culture to be able to replace with commercial starter culture (LK-30 plus) for the manufacture of fermented ham. PMID:27499673

Volatile compounds and odor preferences of ground beef added with garlic and red wine, and irradiated with charcoal pack

NASA Astrophysics Data System (ADS)

Lee, Kyung Haeng; Yun, Hyejeong; Lee, Ju Woon; Ahn, Dong Uk; Lee, Eun Joo; Jo, Cheorun

2012-08-01

Irradiation is the most efficient non-thermal technology for improving hygienic quality and extending the shelf-life of food products. One of the adverse effects of food irradiation, however, is off-flavor production, which significantly affects the sensory preferences for certain foods. In this study, garlic (5%, w/w) and red wine (1:1, w/w) were added to ground beef to increase the radiation sensitivity of pathogens and improve meat odor/flavor. Samples were irradiated at 0 or 5 kGy in the presence of charcoal pack. SPME-GC-MS analysis was performed to measure the changes in the volatile compounds and sensory characteristics of the samples. The amount of total volatile compounds produced from ground beef was greater when the sample was irradiated. When garlic and red wine were added to the ground beef, the amount of volatile compounds significantly increased, and the amount of volatile compounds increased even further after irradiation. However, when the samples were irradiated with charcoal pack, the amount of volatile compounds decreased significantly. Sensory evaluation indicated that charcoal pack significantly increased the odor preferences for both irradiated and non-irradiated ground beef added with garlic. These results indicated that addition of charcoal pack to ground beef could reduce off-odor problems induced by irradiation, and this effect was consistent even when certain additives such as garlic and red wine were added.

The development and testing of a volatile organics concentrator for use in monitoring Space Station water quality

NASA Technical Reports Server (NTRS)

Bodek, Itamar; Ehntholt, Daniel J.; Stolki, Thomas J.; Trabanino, Rudy; Hinsdale, Lloyd; Webb, Johanna; Sauer, Richard L.

1992-01-01

The Volatile Organics Concentrator (VOC) system, designed to attach to a gas chromatograph/mass spectrometer (GC/MS) for the analyses of volatile organic compounds in water on Space Station Freedom, is described. Organic volatiles are collected and concentrated in the VOC by means of two primary solid sorbent tubes and desorbed into the GC/MS system. The paper describes the results of testing the VOC breadboard using a GC/MS system. Evaluations performed on 39 organic compounds recovered from water samples were compared with data for these compounds using direct injection/GC/MS and purge and trap/GC/MS procedures. The results demonstrate that the VOC/GC/MS system's detection limits for the 39 compounds analyzed are comparable to those of the EPA Method 524.2, and for many compounds reaching a factor of 5 lower.

Optimization of headspace solid phase micro-extraction of volatile compounds from papaya fruit assisted by GC-olfactometry.

PubMed

da Rocha, Renier Felinto Julião; da Silva Araújo, Ídila Maria; de Freitas, Sílvia Maria; Dos Santos Garruti, Deborah

2017-11-01

Optimization of the extraction conditions to investigate the volatile composition of papaya fruit involving headspace solid phase micro-extraction was carried out using multivariate strategies such as factorial design and response surface methodology. The performance of different combinations of time for reaching the equilibrium in the headspace and time for maximum extraction of volatiles was evaluated by GC-olfactometry of the extract (intensity of papaya characteristic aroma), number of peaks and total area in the chromatogram. Thirty-two compounds were identified by GC-MS under the optimized extraction conditions, the majority of which were aldehydes, both in number of compounds and area. Major compounds were δ-octalactone, β-citral, benzaldehyde, heptanal, benzyl isothiocyanate, isoamyl acetate, γ-octalactone, (E)-linalool oxide and benzyl alcohol. Seven aldehydes and two other compounds are reported for the first time in papaya's volatile profile.

Description, Properties, and Degradation of Selected Volatile Organic Compounds Detected in Ground Water--A Review of Selected Literature

USGS Publications Warehouse

Lawrence, Stephen J.

2006-01-01

This report provides abridged information describing the most salient properties and biodegradation of 27 chlorinated volatile organic compounds detected during ground-water studies in the United States. This information is condensed from an extensive list of reports, papers, and literature published by the U.S. Government, various State governments, and peer-reviewed journals. The list includes literature reviews, compilations, and summaries describing volatile organic compounds in ground water. This report cross-references common names and synonyms associated with volatile organic compounds with the naming conventions supported by the International Union of Pure and Applied Chemistry. In addition, the report describes basic physical characteristics of those compounds such as Henry's Law constant, water solubility, density, octanol-water partition (log Kow), and organic carbon partition (log Koc) coefficients. Descriptions and illustrations are provided for natural and laboratory biodegradation rates, chemical by-products, and degradation pathways.

Use of integrated indoor concentrations of tracer gases and volatile organic compounds to distinguish soil sources from above-ground sources

EPA Science Inventory

Vapor intrusion refers to the situation in which harmful chemicals [such as halogenated or chlorinated volatile organic compounds (VOC) or petroleum products] in the groundwater or soil volatilize in the vadose zone and migrate into the indoor environment. These chemicals typical...

RECEPTOR MODEL COMPARISONS AND WIND DIRECTION ANALYSES OF VOLATILE ORGANIC COMPOUNDS AND SUBMICROMETER PARTICLES IN AN ARID, BINATIONAL, URBAN AIRSHED

EPA Science Inventory

The relationship between continuous measurements of volatile organic compounds sources and particle number was evaluated at a Photochemical Assessment Monitoring Station Network (PAMS) site located near the U.S.-Mexico Border in central El Paso, TX. Sources of volatile organic...

Recent advances in research on volatile aroma compounds in tomatoes and their impacting factors

USDA-ARS?s Scientific Manuscript database

Aroma is an important sensory attribute of tomatoes. Tomato aroma is formed by a complex mixture of more than 400 volatile compounds, and it plays an important role in the classification and consumer acceptability of tomato products. This article provides a brief overview of the volatile aroma compo...

Extraction and GC determination of volatile aroma compounds from extracts of three plant species of the Apiaceae family

NASA Astrophysics Data System (ADS)

Stan, M.; Soran, M. L.; Varodi, C.; Lung, I.; Copolovici, L.; MǎruÅ£oiu, C.

2013-11-01

Parsley (Petroselinum crispum), dill (Anethum graveolens) and celery (Apium graveolens), three aromatic plants belonging to the Apiaceae (Umbelliferae) botanical family, were selected as sources of essential or volatile oils. Essential oils are composed of a large diversity of volatile aroma compounds. Plant-derived essential oils and extracts have long been used as natural agents in food preservation, pharmaceuticals and medicinal therapies. In the present study, the plant extracts from leaves of parsley, dill and celery, were obtained by maceration, ultrasound-assisted extraction and microwave-assisted extraction. All extractions were performed at 30°C, using different solvents (ethanol, diethyl ether, n-hexane) and solvent mixtures (1:1, v/v). The most effective solvent system for the extraction of volatile aroma compounds was diethyl ether - n-hexane (1:1, v/v). Extraction efficiency and determination of aroma volatiles were performed by GC-FID and GC-MS, respectively. The major volatile compounds present in plant extracts were myristicin, α-phellandrene, β-phellandrene, 1,3,8-p-menthatriene, apiol, dill ether and allyl phenoxyacetate.

Solid-phase microextraction method for the determination of hexanal in hazelnuts as an indicator of the interaction of active packaging materials with food aroma compounds.

PubMed

Pastorelli, S; Valzacchi, S; Rodriguez, A; Simoneau, C

2006-11-01

Fatty foods are susceptible to lipid oxidation resulting in deterioration of product quality due to the generation of off-flavours. Hexanal is a good indicator of rancidity. Therefore, a method based on solid-phase microextraction (SPME) coupled to gas chromatograph with flame ionization detection was developed to determine hexanal formation in hazelnuts during storage. Optimum conditions were as follows: carboxen-polydimethylsiloxane 75 microm fibre, extraction time 10 min, equilibrium time 10 min and equilibrium temperature 60 degrees C. The effect of oxygen scavengers on the oxidation process was also evaluated by measuring hexanal formation in hazelnuts stored with/without oxygen absorber sachets. Oxygen scavengers were shown to reduce oxidation; however, analysis of the sachet revealed that other volatile compounds from the headspace were also absorbed.

Flash pyrolysis of coal, coal maceral, and coal-derived pyrite with on-line characterization of volatile sulfur compounds

USGS Publications Warehouse

Chou, I.-Ming; Lake, M.A.; Griffin, R.A.

1988-01-01

A Pyroprobe flash pyrolysis-gas chromatograph equipped with a flame photometric detector was used to study volatile sulfur compounds produced during the thermal decomposition of Illinois coal, coal macerals and coal-derived pyrite. Maximum evolution of volatile organic sulfur compounds from all coal samples occurred at a temperature of approximately 700??C. At this temperature, the evolution of thiophene, its alkyl isomers, and short-chain dialkyl sulfide compounds relative to the evolution of benzothiophene and dibenzothiophene compounds was greater from coal high in organic sulfur than from coal low in organic sulfur. The variation in the evolution of sulfur compounds observed for three separate coal macerals (exinite, vitrinite, and inertinite) was similar to that observed for whole coal samples. However, the variation trend for the macerals was much more pronounced. Decomposition of coal-derived pyrite with the evolution of elemental sulfur was detected at a temperature greater than 700??C. The results of this study indicated that the gas chromotographic profile of the volatile sulfur compounds produced during flash pyrolysis of coals and coal macerals varied as a function of the amount of organic sulfur that occurred in the samples. Characterization of these volatile sulfur compounds provides a better understanding of the behavior of sulfur in coal during the thermolysis process, which could be incorporated in the design for coal cleaning using flash pyrolysis techniques. ?? 1988.

Calculated volatilization rates of fuel oxygenate compounds and other gasoline-related compounds from rivers and streams

USGS Publications Warehouse

Pankow, J.F.; Rathbun, R.E.; Zogorski, J.S.

1996-01-01

Large amounts of the 'fuel-oxygenate' compound methyl-tert-butyl ether (MTBE) are currently being used in gasoline to reduce carbon monoxide and ozone in urban air and to boost fuel octane. Because MTBE can be transported to surface waters in various ways, established theory was used to calculate half-lives for MTBE volatilizing from flowing surface waters. Similar calculations were made for benzene as a representative of the 'BTEX' group of compounds (benzene, toluene, ethyl benzene, and the xylenes), and for tert-butyl alcohol (TBA). The calculations were made as a function of the mean flow velocity u (m/day), the mean flow depth h (m), the ambient temperature, and the wind speed. In deep, slow-moving flows, MTBE volatilizes at rates which are similar to those for the BTEX compounds. In shallow, fast-moving flows, MTBE volatilizes more slowly than benzene, though in such flows both MTBE and benzene volatilize quickly enough that these differences may often not have much practical significance. TBA was found to be essentially nonvolatile from water.

Volatile sulphur compounds in UHT milk.

PubMed

Al-Attabi, Z; D'Arcy, B R; Deeth, H C

2009-01-01

Several volatile sulphur compounds have been detected in raw and processed milk. These are hydrogen sulphide, methanethiol, carbonyl sulphide, dimethyl sulphide, carbon disulphide, dimethyl disulphide, dimethyl trisulphide, dimethyl sulphoxide, and dimethyl sulphone. Many of these increase in milk during heat processing and are associated with the cooked flavor of heat-treated milks, particularly UHT and sterilized milk. Several researchers have attempted to explain the origin of these volatiles in both raw and processed milk, and how to reduce the associated cooked flavor that has a negative impact on consumer acceptability of processed milk. These compounds are difficult to detect and analyze due to their high volatility, sensitivity to oxidation and heat, and in some cases, their very low concentrations. However, methods of detection and quantification have improved in recent years. Pre-concentration methods such as solid phase microextraction (SPME) together with gas chromatography equipped with sulphur-selective detectors now enable low concentrations of these compounds to be analyzed. In this review, methods of extraction and analyzes of these volatile sulphur compounds are compared, and their occurrence in milk is reviewed.

Biological relevance of volatile organic compounds emitted during the pathogenic interactions between apple plants and Erwinia amylovora.

PubMed

Cellini, Antonio; Buriani, Giampaolo; Rocchi, Lorenzo; Rondelli, Elena; Savioli, Stefano; Rodriguez Estrada, Maria T; Cristescu, Simona M; Costa, Guglielmo; Spinelli, Francesco

2018-01-01

Volatile organic compounds emitted during the infection of apple (Malus pumila var. domestica) plants by Erwinia amylovora or Pseudomonas syringae pv. syringae were studied by gas chromatography-mass spectrometry and proton transfer reaction-mass spectrometry, and used to treat uninfected plants. Infected plants showed a disease-specific emission of volatile organic compounds, including several bio-active compounds, such as hexenal isomers and 2,3-butanediol. Leaf growth promotion and a higher resistance to the pathogen, expressed as a lower bacterial growth and migration in plant tissues, were detected in plants exposed to volatile compounds from E. amylovora-infected plants. Transcriptional analysis revealed the activation of salicylic acid synthesis and signal transduction in healthy plants exposed to volatiles produced by E. amylovora-infected neighbour plants. In contrast, in the same plants, salicylic acid-dependent responses were repressed after infection, whereas oxylipin metabolism was activated. These results clarify some metabolic and ecological aspects of the pathogenic adaptation of E. amylovora to its host. © 2016 BSPP AND JOHN WILEY & SONS LTD.

Nonvolatile, semivolatile, or volatile: redefining volatile for volatile organic compounds.

PubMed

Võ, Uyên-Uyén T; Morris, Michael P

2014-06-01

Although widely used in air quality regulatory frameworks, the term "volatile organic compound" (VOC) is poorly defined. Numerous standardized tests are currently used in regulations to determine VOC content (and thus volatility), but in many cases the tests do not agree with each other, nor do they always accurately represent actual evaporation rates under ambient conditions. The parameters (time, temperature, reference material, column polarity, etc.) used in the definitions and the associated test methods were created without a significant evaluation of volatilization characteristics in real world settings. Not only do these differences lead to varying VOC content results, but occasionally they conflict with one another. An ambient evaporation study of selected compounds and a few formulated products was conducted and the results were compared to several current VOC test methodologies: SCAQMD Method 313 (M313), ASTM Standard Test Method E 1868-10 (E1868), and US. EPA Reference Method 24 (M24). The ambient evaporation study showed a definite distinction between nonvolatile, semivolatile, and volatile compounds. Some low vapor pressure (LVP) solvents, currently considered exempt as VOCs by some methods, volatilize at ambient conditions nearly as rapidly as the traditional high-volatility solvents they are meant to replace. Conversely, bio-based and heavy hydrocarbons did not readily volatilize, though they often are calculated as VOCs in some traditional test methods. The study suggests that regulatory standards should be reevaluated to more accurately reflect real-world emission from the use of VOC containing products. The definition of VOC in current test methods may lead to regulations that exclude otherwise viable alternatives or allow substitutions of chemicals that may limit the environmental benefits sought in the regulation. A study was conducted to examine volatility of several compounds and a few formulated products under several current VOC test methodologies and ambient evaporation. This paper provides ample evidence to warrant a reevaluation of regulatory standards and provides a framework for progressive developments based on reasonable and scientifically justifiable definitions of VOCs.

Volatiles from roasted byproducts of the poultry-processing industry.

PubMed

Wettasinghe, M; Vasanthan, T; Temelli, F; Swallow, K

2000-08-01

Volatiles of roasted chicken breast muscle and byproducts, such as backbones, breastbones, spent bones, and skin, were investigated. Total volatile concentrations ranged from 2030 ppb in the roasted backbones to 4049 ppb in the roasted skin. The major classes of volatile compounds detected in roasted samples were aldehydes (648-1532 ppb) and alcohols (336-1006 ppb). Nitrogen- and/or sulfur-containing compounds were also detected in appreciable quantities (161-706 ppb) in all samples. For all samples, hexanal and 2-methyl-2-buten-1-ol were dominant among the aldehydes and alcohols, respectively. Among the nitrogen- and sulfur-containing compounds, Maillard reaction products, such as tetrahydropyridazines, piperidines, and thiazoles, were the major contributors to the total volatile content in all samples. The composition of volatiles observed in roasted byproducts was markedly different from that of the roasted breast muscle. Therefore, the blending of the byproducts in appropriate proportions or blending of volatile flavor extracts from different byproducts may be necessary to obtain an aroma that mimics roasted chicken aroma.

NATURAL EMISSIONS OF NON-METHANE VOLATILE ORGANIC COMPOUNDS, CARBON MONOXIDE, AND OXIDES OF NITROGEN FROM NORTH AMERICA

EPA Science Inventory

The magnitudes, distributions, controlling processes and uncertainties associated with North American natural emissions of oxidant precursors are reviewed. Natural emissions are repsonsible for a major portion of the compounds, including non-methane volatile organic compounds (N...

Limited effect of anthropogenic nitrogen oxides on secondary organic aerosol formation

DOE PAGES

Zheng, Y.; Unger, N.; Hodzic, A.; ...

2015-12-08

Globally, secondary organic aerosol (SOA) is mostly formed from emissions of biogenic volatile organic compounds (VOCs) by vegetation, but it can be modified by human activities as demonstrated in recent research. Specifically, nitrogen oxides (NO x = NO + NO 2) have been shown to play a critical role in the chemical formation of low volatility compounds. We have updated the SOA scheme in the global NCAR (National Center for Atmospheric Research) Community Atmospheric Model version 4 with chemistry (CAM4-chem) by implementing a 4-product volatility basis set (VBS) scheme, including NO x-dependent SOA yields and aging parameterizations. Small differences aremore » found for the no-aging VBS and 2-product schemes; large increases in SOA production and the SOA-to-OA ratio are found for the aging scheme. The predicted organic aerosol amounts capture both the magnitude and distribution of US surface annual mean measurements from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network by 50 %, and the simulated vertical profiles are within a factor of 2 compared to aerosol mass spectrometer (AMS) measurements from 13 aircraft-based field campaigns across different regions and seasons. We then perform sensitivity experiments to examine how the SOA loading responds to a 50 % reduction in anthropogenic nitric oxide (NO) emissions in different regions. We find limited SOA reductions of 0.9–5.6, 6.4–12.0 and 0.9–2.8 % for global, southeast US and Amazon NO x perturbations, respectively. The fact that SOA formation is almost unaffected by changes in NO x can be largely attributed to a limited shift in chemical regime, to buffering in chemical pathways (low- and high-NO x pathways, O 3 versus NO 3-initiated oxidation) and to offsetting tendencies in the biogenic versus anthropogenic SOA responses.« less

Characterization of volatile compounds responsible for the aroma in naturally fermented sausages by gas chromatography-olfactometry.

PubMed

Olivares, Alicia; Navarro, José Luis; Flores, Mónica

2015-03-01

The objective of this study was to characterize naturally fermented dry sausages produced without the use of microbial starters and to determine which odour-active compounds are responsible for their aroma. The traditional manufacture was responsible for different chemical characteristics and consumer's acceptance. The volatile compounds detected in the headspace comprised a complex mixture of volatile compounds derived from bacterial metabolism (mainly esterase activity of Staphyloccoci), spices and lipid auto-oxidation. The odour-active volatile compounds were identified using gas chromatography coupled to olfactometry (GC-O) using the detection frequency method. The aroma profile was characterized by the presence of several compounds such as acetic acid, ethyl butanoate, hexanal, methional, 1-octen-3-ol, benzeneacetaldehyde and 4-methyl-phenol. However, naturally fermented sausages were also characterized by numerous esters, both ethyl and methyl esters, which impart a wide variety of fruity notes. © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Volatile composition of coffee berries at different stages of ripeness and their possible attraction to the coffee berry borer Hypothenemus hampei (Coleoptera: Curculionidae).

PubMed

Ortiz, Américo; Ortiz, Aristófeles; Vega, Fernando E; Posada, Francisco

2004-09-22

The analysis of volatile emissions of coffee berries in different physiological states of ripeness was performed using dynamic headspace and gas chromatography/mass spectrometry analysis for Coffea arabica, var. Colombia. The composition of the volatiles emitted by coffee berries is dominated by very high levels of alcohols, mainly ethanol, in all stages of ripeness in comparison with other compounds. Overripe coffee berries have high volatile emissions and show a composition dominated mainly by esters followed by alcohols, ketones, and aldehydes. The lowest level compounds were monoterpenes. 2-Methyl furan was detected in various ripening stages; this compound has not been previously reported as a coffee berry volatile. The presence of ethanol and other alcohols in the volatile composition might explain the effectiveness of using traps with mixed alcohols for detection and capture of coffee berry borers.

A Comparison of Parameterizations of Secondary Organic Aerosol Production: Global Budget and Spatiotemporal Variability

NASA Astrophysics Data System (ADS)

Liu, J.; Chen, Z.; Horowitz, L. W.; Carlton, A. M. G.; Fan, S.; Cheng, Y.; Ervens, B.; Fu, T. M.; He, C.; Tao, S.

2014-12-01

Secondary organic aerosols (SOA) have a profound influence on air quality and climate, but large uncertainties exist in modeling SOA on the global scale. In this study, five SOA parameterization schemes, including a two-product model (TPM), volatility basis-set (VBS) and three cloud SOA schemes (Ervens et al. (2008, 2014), Fu et al. (2008) , and He et al. (2013)), are implemented into the global chemical transport model (MOZART-4). For each scheme, model simulations are conducted with identical boundary and initial conditions. The VBS scheme produces the highest global annual SOA production (close to 35 Tg·y-1), followed by three cloud schemes (26-30 Tg·y-1) and TPM (23 Tg·y-1). Though sharing a similar partitioning theory to the TPM scheme, the VBS approach simulates the chemical aging of multiple generations of VOCs oxidation products, resulting in a much larger SOA source, particularly from aromatic species, over Europe, the Middle East and Eastern America. The formation of SOA in VBS, which represents the net partitioning of semi-volatile organic compounds from vapor to condensed phase, is highly sensitivity to the aging and wet removal processes of vapor-phase organic compounds. The production of SOA from cloud processes (SOAcld) is constrained by the coincidence of liquid cloud water and water-soluble organic compounds. Therefore, all cloud schemes resolve a fairly similar spatial pattern over the tropical and the mid-latitude continents. The spatiotemporal diversity among SOA parameterizations is largely driven by differences in precursor inputs. Therefore, a deeper understanding of the evolution, wet removal, and phase partitioning of semi-volatile organic compounds, particularly above remote land and oceanic areas, is critical to better constrain the global-scale distribution and related climate forcing of secondary organic aerosols.

Volatile Organic Compound Emissions by Agricultural Crops

NASA Astrophysics Data System (ADS)

Ormeno, E.; Farres, S.; Gentner, D.; Park, J.; McKay, M.; Karlik, J.; Goldstein, A.

2008-12-01

Biogenic Volatile Organic Compounds (BVOCs) participate in ozone and aerosol formation, and comprise a substantial fraction of reactive VOC emission inventories. In the agriculturally intensive Central Valley of California, emissions from crops may substantially influence regional air quality, but emission potentials have not been extensively studied with advanced instrumentation for many important crops. Because crop emissions may vary according to the species, and California emission inventories are constructed via a bottom-up approach, a better knowledge of the emission rate at the species-specific level is critical for reducing uncertainties in emission inventories and evaluating emission model performance. In the present study we identified and quantified the BVOCs released by dominant agricultural crops in California. A screening study to investigate both volatile and semivolatile BVOC fractions (oxygenated VOCs, isoprene, monoterepenes, sesquiterpenes, etc.) was performed for 25 crop species (at least 3 replicates plants each), including branch enclosures of woody species (e.g. peach, mandarin, grape, pistachio) and whole plant enclosures for herbaceous species (e.g. onion, alfalfa, carrot), through a dynamic cuvette system with detection by PTRMS, in-situ GCMS/FID, and collection on carbon-based adsorbents followed by extraction and GCMS analysis. Emission data obtained in this study will allow inclusion of these crops in BVOC emission inventories and air quality simulations.

Modelling of Criegee Intermediates using the 3-D global model, STOCHEM-CRI and investigating their global impacts on Secondary Organic Aerosol formation

NASA Astrophysics Data System (ADS)

Khan, M. Anwar H.; Cooke, Michael; Utembe, Steve; Archibald, Alexander; Derwent, Richard; Jenkin, Mike; Lyons, Kyle; Kent, Adam; Percival, Carl; Shallcross, Dudley E.

2016-04-01

Gas phase reactions of ozone with unsaturated compounds form stabilized Criegee intermediates (sCI) which play an important role in controlling the budgets of many tropospheric species including OH, organic acids and secondary organic aerosols (SOA). Recently sCI has been proposed to play a significant role in atmospheric sulfate and nitrate chemistry by forming sulfuric acid (promoter of aerosol formation) and nitrate radical (a powerful oxidizing agent). sCI can also undergo association reactions with water, alcohols, and carboxylic acids to form hydroperoxides and with aldehydes and ketones to form secondary ozonides. The products from these reactions are low volatility compounds which can contribute to the formation of SOA. The importance of plant emitted alkenes (isoprene, monoterpenes, sesquiterpenes) in the production of SOA through sCI formation have already been investigated in laboratory studies. However, the SOA formation from these reactions are absent in current global models. Thus, the formation of SOA has been incorporated in the global model, STOCHEM-CRI, a 3-D global chemistry transport model and the role of CI chemistry in controlling atmospheric composition and climate, and the influence of water vapor has been discussed in the study.

Identification of Campylobacter infection in chickens from volatile faecal emissions.

PubMed

Garner, Catherine E; Smith, Stephen; Elviss, Nicola C; Humphrey, Tom J; White, Paul; Ratcliffe, Norman M; Probert, Christopher S

2008-06-01

Volatile organic compounds from chicken faeces were investigated as biomarkers for Campylobacter infection. Campylobacter are major poultry-borne zoonotic pathogens, colonizing the avian intestinal tract. Chicken faeces are the principal source of contamination of carcasses. Fresh faeces were collected on farm sites, and Campylobacter status established microbiologically. Volatile organic compounds were pre-concentrated from the headspace above 71 separate faecal samples using solid-phase microextraction and separated and identified by gas chromatography/mass spectrometry. A Campylobacter-specific profile was identified using six of the extracted volatile organic compounds. The model developed reliably identified the presence or absence of Campylobacter in >95% of chickens. The volatile biomarker identification approach for assessing avian infection is a novel approach to enhancing biosecurity in the poultry industry and should reduce the risk of disease transmission to humans.

Analysis of Volatile Components of Cape Gooseberry (Physalis peruviana L.) Grown in Turkey by HS-SPME and GC-MS

PubMed Central

2014-01-01

Volatile components in cape gooseberry fruit at ripe stage were collected using headspace-solid phase microextraction, and analyzed by gas chromatography-mass spectrometry. Three solid phase microextraction fiber coatings (DVB/CAR/PDMS, CAR/PDMS, and PDMS/DVB) were tested for evaluation of volatile compounds. DVB/CAR/PDMS fiber showed a strong extraction capacity for volatile compounds and produced the best result in case of total peak areas. A total of 133 volatile compounds were identified in fruit pulp; among them 1-hexanol (6.86%), eucalyptol (6.66%), ethyl butanoate (6.47%), ethyl octanoate (4.01%), ethyl decanoate (3.39%), 4-terpineol (3.27%), and 2-methyl-1-butanol (3.10%) were the major components in the sample extracts. PMID:24741358

Analysis of volatile components of cape gooseberry (Physalis peruviana L.) grown in Turkey by HS-SPME and GC-MS.

PubMed

Yilmaztekin, Murat

2014-01-01

Volatile components in cape gooseberry fruit at ripe stage were collected using headspace-solid phase microextraction, and analyzed by gas chromatography-mass spectrometry. Three solid phase microextraction fiber coatings (DVB/CAR/PDMS, CAR/PDMS, and PDMS/DVB) were tested for evaluation of volatile compounds. DVB/CAR/PDMS fiber showed a strong extraction capacity for volatile compounds and produced the best result in case of total peak areas. A total of 133 volatile compounds were identified in fruit pulp; among them 1-hexanol (6.86%), eucalyptol (6.66%), ethyl butanoate (6.47%), ethyl octanoate (4.01%), ethyl decanoate (3.39%), 4-terpineol (3.27%), and 2-methyl-1-butanol (3.10%) were the major components in the sample extracts.

Characterization of Volatile Compounds with HS-SPME from Oxidized n-3 PUFA Rich Oils via Rancimat Tests.

PubMed

Yang, Kai-Min; Cheng, Ming-Ching; Chen, Chih-Wei; Tseng, Chin-Yin; Lin, Li-Yun; Chiang, Po-Yuan

2017-02-01

Algae oil and fish oil are n-3 PUFA mainstream commercial products. The various sources for the stability of n-3 PUFA oxidation are influenced by the fatty acid composition, extraction and refined processing. In this study, the oil stability index (OSI) occurs within 2.3 to 7.6 hours with three different n-3 PUFA rich oil. To set the OSI in the Rancimat test as the oil stability limit and observed various degrees of oxidation (0, 25, 50, 75, 100 and 125%). The volatile oxidation compounds were analyzed via headspace-solid phase microextraction (HS-SPME) and GC/MS. We detected 51 volatile compound variations during the oxidation, which were composed of aldehydes, hydrocarbons, cyclic compounds, alcohols, benzene compounds, ketones, furans, ester and pyrrolidine. The off-flavor characteristics can be strongly influenced by the synergy effects of volatile oxidation compounds. Chemometric analysis (PCA and AHC) was applied to identify the sensitive oxidation marker compounds, which included a (E,E)-2,4-heptadienal appropriate marker, via lipid oxidation in the n-3 PUFA rich oil.

Stability of encapsulated beef-like flavourings prepared from enzymatically hydrolysed mushroom proteins with other precursors under conventional and microwave heating.

PubMed

Lotfy, Shereen N; Fadel, Hoda H M; El-Ghorab, Ahmed H; Shaheen, Mohamed S

2015-11-15

A comparative study was carried out between two beef-like flavourings prepared by conventional and microwave heating (CBF and MBF) of enzymatic hydrolysate of mushroom protein with other flavour precursors. GC-MS analysis of the isolated volatiles revealed that the thiol containing compounds were the predominate in both samples. However, MBF comprised higher concentration of these compounds (13.84 ± 0.06%) than CBF (10.74 ± 0.06%). The effect of microencapsulation with gum Arabic by using spray drying on the odour profile and volatile compounds of the two encapsulated samples (E-CBF and E-MBF) was investigated. The results revealed significant qualitative and quantitative variations in the volatiles of both samples. The highly volatile compounds decreased remarkably in concentration with encapsulation, while the pyrazines, thiazoles and disulphides showed opposite trend. The significant decrease in the thiol containing compounds in E-CBF and E-MBF were attributed to their oxidation to other compounds such as disulphide compounds which showed significant increase in the encapsulated samples. Copyright © 2015 Elsevier Ltd. All rights reserved.

Quantifying the Contribution of Grape Hexoses to Wine Volatiles by High-Precision [U13C]-Glucose Tracer Studies

PubMed Central

Nisbet, Mark A.; Tobias, Herbert J.; Brenna, J. Thomas; Sacks, Gavin L.; Mansfield, Anna Katharine

2016-01-01

Many fermentation volatiles important to wine aroma potentially arise from yeast metabolism of hexose sugars, but assessing the relative importance of these pathways is challenging due to high endogenous hexose substrate concentrations. To overcome this problem, gas chromatography combustion isotope ratio mass spectrometry (GC-C-IRMS) was used to measure high-precision 13C/12C isotope ratios of volatiles in wines produced from juices spiked with tracer levels (0.01–1 APE) of uniformly labeled [U-13C]-glucose. The contribution of hexose to individual volatiles was determined from the degree of 13C enrichment. As expected, straight-chain fatty acids and their corresponding ethyl esters were derived almost exclusively from hexoses. Most fusel alcohols and their acetate esters were also majority hexose-derived, indicating the importance of anabolic pathways for their formation. Only two compounds were not derived primarily from hexoses (hexanol and isobutyric acid). This approach can be extended to other food systems or substrates for studying precursor–product relationships. PMID:24960193

REVIEW OF VOLATILE ORGANIC COMPOUND SOURCE APPORTIONMENT BY CHEMICAL MASS BALANCE. (R826237)

EPA Science Inventory

The chemical mass balance (CMB) receptor model has apportioned volatile organic compounds (VOCs) in more than 20 urban areas, mostly in the United States. These applications differ in terms of the total fraction apportioned, the calculation method, the chemical compounds used ...

RECOVERY OF SEMI-VOLATILE ORGANIC COMPOUNDS DURING SAMPLE PREPARATION: IMPLICATIONS FOR CHARACTERIZATION OF AIRBORNE PARTICULATE MATTER

EPA Science Inventory

Semi-volatile compounds present special analytical challenges not met by conventional methods for analysis of ambient particulate matter (PM). Accurate quantification of PM-associated organic compounds requires validation of the laboratory procedures for recovery over a wide v...

40 CFR 60.622 - Standards for volatile organic compounds.

Code of Federal Regulations, 2010 CFR

2010-07-01

... compounds. 60.622 Section 60.622 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Petroleum Dry Cleaners § 60.622 Standards for volatile organic compounds. (a) Each affected petroleum solvent dry cleaning dryer that is installed at a petroleum dry cleaning plant after December 14, 1982...

40 CFR 60.622 - Standards for volatile organic compounds.

Code of Federal Regulations, 2011 CFR

2011-07-01

... compounds. 60.622 Section 60.622 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Petroleum Dry Cleaners § 60.622 Standards for volatile organic compounds. (a) Each affected petroleum solvent dry cleaning dryer that is installed at a petroleum dry cleaning plant after December 14, 1982...

40 CFR 60.622 - Standards for volatile organic compounds.

Code of Federal Regulations, 2012 CFR

2012-07-01

... compounds. 60.622 Section 60.622 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Petroleum Dry Cleaners § 60.622 Standards for volatile organic compounds. (a) Each affected petroleum solvent dry cleaning dryer that is installed at a petroleum dry cleaning plant after December 14, 1982...

Study of β-cyclodextrin inclusion complexes with volatile molecules geraniol and α-terpineol enantiomers in solid state and in solution

NASA Astrophysics Data System (ADS)

Ceborska, Magdalena; Szwed, Kamila; Asztemborska, Monika; Wszelaka-Rylik, Małgorzata; Kicińska, Ewa; Suwińska, Kinga

2015-11-01

Geraniol and α-terpineol are insoluble in water volatile compounds. α-Terpineol is a potentially important agent for medical applications. Formation of molecular complexes with β-cyclodextrin would lead to the increase of water solubility and bioavailability. β-Cyclodextrin forms 2:2 inclusion complexes with both enantiomers of α-terpineol and their precursor geraniol. Solid state complexes are thoroughly characterized by single X-ray crystallography and their stability over vast range of temperatures is proven by TG analysis. Intermolecular host-guest, host-host and guest-guest interactions give good insight into the nature of formed inclusion complexes. Stability constants of the complexes in solution are determined by HPLC.

Combustion Synthesis Technology Applied to In-situ Resource Utilization

DTIC Science & Technology

2006-06-15

or bond energies. When both the precursor salts and the fuel are water soluble, a good homogenization can be achieved in the solution. In the...metallic compounds, e.g. Ni-Al. Steel processing additives, e.g. ferro-nitrides. Electrodes for electrolysis of corrosive media, e.g. TiN, TiB2...reactants; 4. Spreading of a molten phase; 5. Gasification of volatile impurities and reactants; 6. Chemical reaction with initial product formation; 7

A post-Galileo view of Io's interior

USGS Publications Warehouse

Keszthelyi, L.; Jaeger, W.L.; Turtle, E.P.; Milazzo, M.; Radebaugh, J.

2004-01-01

We present a self-consistent model for the interior of Io, taking the recent Galileo data into account. In this model, Io has a completely molten core, substantially molten mantle, and a very cold lithosphere. Heat from magmatic activity can mobilize volatile compounds such as SO2 in the lithosphere, and the movement of such cryogenic fluids may be important in the formation of surface features including sapping scarps and paterae. ?? Published by Elsevier Inc.

Comparison of two common adsorption materials for thermal desorption gas chromatography - mass spectrometry of biogenic volatile organic compounds.

PubMed

Marcillo, Andrea; Jakimovska, Viktorija; Widdig, Anja; Birkemeyer, Claudia

2017-09-08

Volatile organic compounds (VOCs) are commonly collected from gaseous samples by adsorption to materials such as the porous polymer Tenax TA. Adsorbed compounds are subsequently released from these materials by thermal desorption (TD) and separated then by gas chromatography (GC) with flame ionization (FID) or mass spectrometry (MS) detection. Tenax TA is known to be particularly suitable for non-polar to semipolar volatiles, however, many volatiles from environmental and biological samples possess a rather polar character. Therefore, we tested if the polymer XAD-2, which so far is widely used to adsorb organic compounds from aqueous and organic solvents, could provide a broader coverage for (semi)polar VOCs during gas-phase sampling. Mixtures of volatile compounds covering a wide range of volatility (bp. 20-256°C) and different chemical classes were introduced by liquid spiking into sorbent tubes with one of the two porous polymers, Tenax TA or XAD-2, and analyzed by TD/GC-MS. At first, an internal standard mixture composed of 17 authentic standards was used to optimize desorption temperature with respect to sorbent degradation and loading time for calibration. Secondly, we tested the detectability of a complex standard mixture composed of 57 volatiles, most of them common constituents of the body odor of mammals. Moreover, the performance of XAD-2 compared with Tenax TA was assessed as limit of quantitation and linearity for the internal standard mixture and 33 compounds from the complex standard mixture. Volatiles were analyzed in a range between 0.01-∼250ng/tube depending on the compound and material. Lower limits of quantitation were between 0.01 and 3 ng±<25% RSD (R 2 >0.9). Interestingly, we found different kinetics for compound adsorption with XAD-2, and a partially better sensitivity in comparison with Tenax TA. For these analytes, XAD-2 might be recommended as an alternative of Tenax TA for TD/GC-MS analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

Generation of sub-part-per-billion gaseous volatile organic compounds at ambient temperature by headspace diffusion of aqueous standards through decoupling between ideal and nonideal Henry's law behavior.

PubMed

Kim, Yong-Hyun; Kim, Ki-Hyun

2013-05-21

In the analysis of volatile organic compounds in air, the preparation of their gaseous standards at low (sub-ppb) concentration levels with high reliability is quite difficult. In this study, a simple dynamic headspace-based approach was evaluated as a means of generating vapor-phase volatile organic compounds from a liquid standard in an impinger at ambient temperature (25 °C). For a given sampling time, volatile organic compound vapor formed in the headspace was swept by bypassing the sweep gas through the impinger and collected four times in quick succession in separate sorbent tubes. In each experiment, a fresh liquid sample was used for each of the four sampling times (5, 10, 20, and 30 min) at a steady flow rate of 50 mL min(-1). The air-water partitioning at the most dynamic (earliest) sweeping stage was established initially in accord with ideal Henry's law, which was then followed by considerably reduced partitioning in a steady-state equilibrium (non-ideal Henry's law). The concentrations of gaseous volatile organic compounds, collected after the steady-state equilibrium, reached fairly constant values: for instance, the mole fraction of toluene measured at a sweeping interval of 10 and 30 min averaged 1.10 and 0.99 nmol mol(-1), respectively (after the initial 10 min sampling). In the second stage of our experiment, the effect of increasing the concentrations of liquid spiking standard was also examined by collecting sweep gas samples from two consecutive 10 min runs. The volatile organic compounds, collected in the first and second 10 min sweep gas samples, exhibited ideal and nonideal Henry's law behavior, respectively. From this observation, we established numerical relationships to predict the mole fraction (or mixing ratio) of each volatile organic compound in steady-state equilibrium in relation to the concentration of standard spiked into the system. This experimental approach can thus be used to produce sub-ppb levels of gaseous volatile organic compounds in a constant and predictable manner.

POLYCYCLIC AROMATIC HYDROCARBONS (PAHS) AND OTHER SEMI-VOLATILE ORGANIC COMPOUNDS COLLECTED IN NEW YORK CITY IN RESPONSE TO THE EVENTS OF 9/11

EPA Science Inventory

Concentrations of over 60 non-polar semi-volatile and non-volatile organic compounds were measured in Lower Manhattan, New York using a high capacity Integrated Organic Gas and Particle Sampler, after the initial destruction of the World Trade Center. The results indicate that th...

POLYCYLIC AROMATIC HYDROCARBONS (PAHS) AND OTHER SEMI-VOLATILE ORGANIC COMPOUNDS COLLECTED IN NEW YORK CITY IN RESPONSE TO THE EVENTS OF 9/11

EPA Science Inventory

Concentrations of over 60 non-polar semi-volatile and non-volatile organic compounds were measured in Lower Manhattan, New York using a high capacity Integrated Organic Gas an Particle Sampler, after the initial destruction of the World Trade Center. The results indicate that t...

POLYCYCLIC AROMATIC HYDROCARBONS (PAHS) AND OTHER SEMI-VOLATILE ORGANIC COMPOUNDS COLLECTED IN NEW YORK CITY IN RESPONSE TO THE EVENTS OF 9/11

EPA Science Inventory

Concentrations of over 60 non-polar semi-volatile and non-volatile organic compounds were measured in Lower Manhattan, New York using a high capacity Integrated Organic Gas and Particle Sampler, after the initial destruction of the World Trade Center. The results indicate that ...

Effect of wild strains used as starter cultures and adjunct cultures on the volatile compounds of the Pecorino Siciliano cheese.

PubMed

Randazzo, C L; Pitino, I; De Luca, S; Scifò, G O; Caggia, C

2008-03-20

The effect of six wild strains on the volatile profile of the PS cheese was investigated and compared to that generated from industrial starters generally used to produce PS cheese. All cheeses were subjected to microbiological, physicochemical, and volatile compounds analyses. The DGGE of the 16S rDNA analysis was also applied. The volatile compounds generated during ripening were studied through the SPME and the GC-MS methods. No difference was detected between the experimental and control cheeses throughout chemical and microbiological analyses, while the DGGE results showed the presence of Streptococcus thermophilus in all cheeses, and the dominance of Enterococcus durans, Lactobacillus rhamnosus, and Lactobacillus casei in most of the experimental cheeses. Moreover, the presence of Lactococcus lactis species as in the control and in the experimental P2 and P4 cheeses was also revealed. The SPME results showed more pronounced volatile compounds in the experimental cheese samples than in the control ones.

Comprehensive comparative analysis of volatile compounds in citrus fruits of different species.

PubMed

Zhang, Haipeng; Xie, Yunxia; Liu, Cuihua; Chen, Shilin; Hu, Shuangshuang; Xie, Zongzhou; Deng, Xiuxin; Xu, Juan

2017-09-01

The volatile profiles of fruit peels and juice sacs from 108 citrus accessions representing seven species were analyzed. Using GC-MS 162 and 107 compounds were determined in the peels and juice sacs, respectively. In the peels, monoterpene alcohols were accumulated in loose-skin mandarins; clementine tangerines and papedas were rich in sesquiterpene alcohols, sesquiterpenes, monoterpene alcohols and monoterpene aldehydes. β-pinene and sabinene were specifically accumulated in 4 of 5 lemon germplasms. Furthermore, concentrations of 34 distinctive compounds were selected to best represent the volatile profiles of seven species for HCA analysis, and the clustering results were in agreement with classic citrus taxonomy. Comparison of profiles from different growing seasons and production areas indicated that environmental factors play important roles in volatile metabolism. In addition, a few citrus germplasms that accumulated certain compounds were determined as promising breeding materials. Notably, volatile biosynthesis via MVA pathway in C. ichangensis 'Huaihua' was enhanced. Copyright © 2017. Published by Elsevier Ltd.

A chemometrics as a powerful tool in the elucidation of the role of metals in the biosynthesis of volatile organic compounds in Hungarian thyme samples.

PubMed

Arsenijević, Jelena; Marković, Jelena; Soštarić, Ivan; Ražić, Slavica

2013-10-01

The volatile fraction of the leaves of Thymus pannonicus All. (Lamiaceae) was analyzed by headspace extraction followed by GC-FID and GC-MS analysis. The different headspace profiles were recognized, with citral and with monoterpene hydrocarbons as dominant compounds. In addition, the determination of Cr, Co, Ni, Mo, Cu, Zn, Mn, Fe, Mg, Ca, K and Na was conducted by spectroscopic techniques (FAAS, GFAAS and ICP-OES). In order to evaluate the relationship between volatile organic compounds and metals, a chemometrics approach was applied. The data obtained by analysis of the headspace and elemental content were subjected to correlation analysis, factor analysis, principal component analysis and cluster analysis. A number of significant correlations of metals with plant volatiles were found. Correlation of Zn with citral, Mn with oxygenated monoterpenes and Mg with β-bourbonene, could be explained by involvement of metals in the biosynthesis of volatile organic compounds. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Fatty acid composition and volatile compounds of caviar from farmed white sturgeon (Acipenser transmontanus).

PubMed

Caprino, Fabio; Moretti, Vittorio Maria; Bellagamba, Federica; Turchini, Giovanni Mario; Busetto, Maria Letizia; Giani, Ivan; Paleari, Maria Antonietta; Pazzaglia, Mario

2008-06-09

The present study was conducted to characterize caviar obtained from farmed white sturgeons (Acipenser transmontanus) subjected to different dietary treatments. Twenty caviar samples from fish fed two experimental diets containing different dietary lipid sources have been analysed for chemical composition, fatty acids and flavour volatile compounds. Fatty acid make up of caviar was only minimally influenced by dietary fatty acid composition. Irrespective of dietary treatments, palmitic acid (16:0) and oleic acid (OA, 18:1 n-9) were the most abundant fatty acid followed by docosahexaenoic acid (DHA, 22:6 n-3) and eicopentaenoic (EPA, 20:5 n-3). Thirty-three volatile compounds were isolated using simultaneous distillation-extraction (SDE) and identified by GC-MS. The largest group of volatiles were represented by aldehydes with 20 compounds, representing the 60% of the total volatiles. n-Alkanals, 2-alkenals and 2,4-alkadienals are largely the main responsible for a wide range of flavours in caviar from farmed white surgeon.

Controlling the reaction between boron-containing sealing glass and a lanthanum-containing cathode by adding Nb2O5

NASA Astrophysics Data System (ADS)

Zhao, Dandan; Fang, Lihua; Tang, Dian; Zhang, Teng

2016-09-01

In solid oxide fuel cell (SOFC) stacks, the volatile boron species present in the sealing glass often react with the lanthanum-containing cathode, degrading the activity of the cathode (this phenomenon is known as boron poisoning). In this work, we report that this detrimental reaction can be effectively reduced by doping bismuth-containing borosilicate sealing glass-ceramic with a niobium dopant. The addition of Nb2O5 not only condenses the [SiO4] structural units in the glass network, but also promotes the conversion of [BO3] to [BO4]. Moreover, the Nb2O5 dopant enhances the formation of boron-containing phases (Ca3B2O6 and CaB2Si2O8), which significantly reduces the volatility of boron compounds in the sealing glass, suppressing the formation of LaBO3 in the reaction couple between the glass and the cathode. The reported results provide a new approach to solve the problem of boron poisoning.

Comparison of methods for determining volatile compounds in milk, cheese, and whey powder

USDA-ARS?s Scientific Manuscript database

Solid phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) are commonly used for qualitative and quantitative analysis of volatile compounds in various dairy products, but conditions have to be adjusted for optimal SPME release while not generating new compounds that are abs...

Predicting the emission of volatile organic compounds from silage systems

USDA-ARS?s Scientific Manuscript database

As a precursor to smog, emission of volatile organic compounds (VOCs) to the atmosphere is an environmental concern in some regions. The major VOC emission source from farms is silage, with emissions coming from the silo face, mixing wagon, and feed bunk. The major compounds emitted are alcohols wit...

Volatile organic compound emissions from silage systems

USDA-ARS?s Scientific Manuscript database

As a precursor to smog, emission of volatile organic compounds (VOCs) to the atmosphere is an environmental concern in some regions. The major source from farms is silage, with emissions coming from the silo face, mixing wagon, and feed bunk. The major compounds emitted are alcohols with other impor...

76 FR 41086 - Approval and Promulgation of Air Quality Implementation Plans; Ohio; Volatile Organic Compound...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-13

... Promulgation of Air Quality Implementation Plans; Ohio; Volatile Organic Compound Reinforced Plastic Composites... compound (VOC) emissions from reinforced plastic composites production operations. This rule applies to any facility that has reinforced plastic composites production operations. This rule is approvable because it...

Waterborne Diseases & Illnesses

MedlinePlus

... Lead Arsenic Volatile Organic Compounds Plastics Pesticides Climate Change Climate Change Home What is Climate Change Greenhouse Gases ... Lead Arsenic Volatile Organic Compounds Plastics Pesticides Climate Change Climate Change Home What is Climate Change Greenhouse Gases ...

Aqueous-phase oxidation of green leaf volatiles by hydroxyl radical as a source of SOA: Product identification from methyl jasmonate and methyl salicylate oxidation

NASA Astrophysics Data System (ADS)

Hansel, Amie K.; Ehrenhauser, Franz S.; Richards-Henderson, Nicole K.; Anastasio, Cort; Valsaraj, Kalliat T.

2015-02-01

Green leaf volatiles (GLVs) are a group of biogenic volatile organic compounds (BVOCs) released into the atmosphere by vegetation. BVOCs produce secondary organic aerosol (SOA) via gas-phase reactions, but little is known of their aqueous-phase oxidation as a source of SOA. GLVs can partition into atmospheric water phases, e.g., fog, mist, dew or rain, and be oxidized by hydroxyl radicals (˙OH). These reactions in the liquid phase also lead to products that have higher molecular weights, increased polarity, and lower vapor pressures, ultimately forming SOA after evaporation of the droplet. To examine this process, we investigated the aqueous, ˙OH-mediated oxidation of methyl jasmonate (MeJa) and methyl salicylate (MeSa), two GLVs that produce aqueous-phase SOA. High performance liquid chromatography/electrospray ionization mass spectrometry (HPLC-ESI-MS) was used to monitor product formation. The oxidation products identified exhibit higher molecular mass than their parent GLV due to either dimerization or the addition of oxygen and hydroxyl functional groups. The proposed structures of potential products are based on mechanistic considerations combined with the HPLC/ESI-MS data. Based on the structures, the vapor pressure and the Henry's law constant were estimated with multiple methods (SPARC, SIMPOL, MPBPVP, Bond and Group Estimations). The estimated vapor pressures of the products identified are significantly (up to 7 orders of magnitude) lower than those of the associated parent compounds, and therefore, the GLV oxidation products may remain as SOA after evaporation of the water droplet. The contribution of the identified oxidation products to SOA formation is estimated based on measured HPLC-ESI/MS responses relative to previous aqueous SOA mass yield measurements.

Groundwater geochemical and selected volatile organic compound data, Operable Unit 1, Naval Undersea Warfare Center, Division Keyport, Washington, June 2011

USGS Publications Warehouse

Huffman, Raegan L.; Frans, L.M.

2012-01-01

Previous investigations indicate that concentrations of chlorinated volatile organic compounds are substantial in groundwater beneath the 9-acre former landfill at Operable Unit 1, Naval Undersea Warfare Center, Division Keyport, Washington. Phytoremediation combined with ongoing natural attenuation processes was the preferred remedy selected by the U.S. Navy, as specified in the Record of Decision for the site. The U.S. Navy planted two hybrid poplar plantations on the landfill in spring 1999 to remove and to control the migration of chlorinated volatile organic compounds in shallow groundwater. The U.S. Geological Survey has continued to monitor groundwater geochemistry to ensure that conditions remain favorable for contaminant biodegradation as specified in the Record of Decision. This report presents groundwater geochemical and selected volatile organic compound data collected at Operable Unit 1 by the U.S. Geological Survey during June 20-22, 2011, in support of long-term monitoring for natural attenuation. In 2011, groundwater samples were collected from 13 wells and 9 piezometers. Samples from all wells and piezometers were analyzed for redox sensitive constituents and dissolved gases, and samples from 5 of 13 wells and all piezometers also were analyzed for chlorinated volatile organic compounds. Concentrations of redox sensitive constituents measured in 2011 were consistent with previous years, with dissolved oxygen concentrations all at 0.4 milligram per liter or less; little to no detectable nitrate; abundant dissolved manganese, iron, and methane; and commonly detected sulfide. The reductive declorination byproducts - methane, ethane, and ethene - were either not detected in samples collected from the upgradient wells in the landfill and the upper aquifer beneath the northern phytoremediation plantation or were detected at concentrations less than those measured in 2010. Chlorinated volatile organic compound concentrations in 2011 at most piezometers were similar to or slightly less than chlorinated volatile organic compound concentrations measured in previous years. For the upper aquifer beneath the southern phytoremediation plantation, chlorinated volatile organic compound concentrations in 2011 in groundwater from the piezometers were extremely high and continued to vary considerably over space and between years. At piezometer P1-9, the total chlorinated volatile organic compound concentrations increased from 9,500 micrograms per liter in 2010 to more than 44,000 micrograms per liter in 2011. Total chlorinated volatile organic compound concentrations decreased at piezometers P1-6, P1-7, and P1-10 compared to the concentrations measured in 2010. One or both of the reductive dechlorination byproducts ethane and ethene were detected at all piezometers and three of the four wells in the southern plantation. For the intermediate aquifer, concentrations of redox sensitive constituents and chlorinated volatile organic compounds in 2011 were consistent with concentrations measured in previous years, with the exception of notable decreases in sulfate and chloride concentrations at well MW1-28. Concentrations of the reductive dechlorination byproducts ethane and ethene decreased at wells MW1-25 and MW1-28 compared to previously measured concentrations.

Structural changes in plastids of developing Splachnum ampullaceum sporophytes and relationship to odour production

PubMed Central

McCuaig, B.; Dufour, S. C.; Raguso, R. A.; Bhatt, A. P.; Marino, P.

2014-01-01

Many mosses of the family Splachnaceae are entomophilous and rely on flies for spore dispersal. Splachnum ampullaceum produces a yellow- or pink-coloured hypophysis that releases volatile compounds, attracting flies to the mature moss. The biosynthetic sources of the visual and aromatic cues within the hypophysis have not been identified, and may be either symbiotic cyanobacteria or chromoplasts that break down lipids into volatile compounds. Here, we used transmission electron microscopy and gas chromatography-mass spectrometry (GC-MS) to investigate the sources of these attractants, focusing on different tissues and stages of maturation. Microscopy revealed an abundance of plastids within the hypophysis, while no symbiotic bacteria were observed. During plant maturation, plastids differentiated from amyloplasts with large starch granules to photosynthetic chloroplasts and finally to chromoplasts with lipid accumulations. We used GC-MS to identify over 50 volatile organic compounds from mature sporophytes including short-chain oxygenated compounds, unsaturated irregular terpenoids, fatty acid-derived 6- and 8-carbon alcohols and ketones, and the aromatic compounds acetophenone and p-cresol. The hypophysis showed localised production of pungent volatiles, mainly short-chain fermentation compounds and p-cresol. Some of these volatiles have been shown to be produced from lipid oxidase degradation of linolenic acid within chromoplasts. However, other compounds (such as cyclohexanecarboxylic acid esters) may have a microbial origin. Further investigation is necessary to identify the origin of fly attractants in these mosses. PMID:25213550

SITE TECHNOLOGY CAPSULE: ZENOGEM™ WASTEWATER TREATMENT PROCESS

EPA Science Inventory

Zenon Environmental System's ZenoGem™ Wastewater Treatment Process treats aqueous media contaminated with volatile/semi-volatile organic compounds. This technology combines aerobic biological treatment to remove biodegradable organic compounds with ultrafiltration to separate res...

Indoor Semi-volatile Organic Compounds (i-SVOC) Version 1.0

EPA Pesticide Factsheets

i-SVOC Version 1.0 is a general-purpose software application for dynamic modeling of the emission, transport, sorption, and distribution of semi-volatile organic compounds (SVOCs) in indoor environments.

Arsenic (Environmental Health Student Portal)

MedlinePlus

... Lead Arsenic Volatile Organic Compounds Plastics Pesticides Climate Change Climate Change Home What is Climate Change Greenhouse Gases ... Lead Arsenic Volatile Organic Compounds Plastics Pesticides Climate Change Climate Change Home What is Climate Change Greenhouse Gases ...

Architectural Coatings: National Volatile Organic Compounds Emission Standards

EPA Pesticide Factsheets

Read about the section 183(e) rule for volatile organic compounds for architectural coatings. Read the rule summary and history, find the code of federal regulations test, and additional documents, including compliance information.

40 CFR 60.712 - Standards for volatile organic compounds.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Magnetic Tape Coating Facilities § 60.712 Standards for volatile organic compounds. Each owner or operator... (other than a condenser) on a magnetic tape coating operation shall control emissions from the coating...

40 CFR 60.712 - Standards for volatile organic compounds.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Magnetic Tape Coating Facilities § 60.712 Standards for volatile organic compounds. Each owner or operator... (other than a condenser) on a magnetic tape coating operation shall control emissions from the coating...

Effects of Methyl Jasmonate on the Composition of Volatile Compounds in Pyropia yezoensis

NASA Astrophysics Data System (ADS)

He, Lihong; Wang, Liang; Wang, Linfang; Shen, Songdong

2018-04-01

Volatile organic compounds in marine algae have been reported to comprise characteristic flavor of algae and play an important role in their growth, development and defensive response. Yet their biogeneration remain largely unknown. Here we studied the composition of volatile compouds in Pyropia yezoensis and their variations in response to methyl jasmonate (MeJA) and diethyldithiocarbamic acid (DIECA) treatment using gas chromatography-mass spectrometry (GC-MS). A total of 44 compounds belonging to the following chemical classes (n) were identified, including aldehydes (11), alcohols (8), acids and esters (6), alkanes (5), ketones (5), alkenes (3), and S- or N-containing miscellaneous compounds (6). External treatment with plant hormone MeJA increased the content of 1-dodecanol, 4-heptenal, and 2-propenoic acid-2-methyl dodecylester, but decreased the content of phytol, 3-heptadecene, 2-pentadecanone, and isophytol. When pretreated with DIECA, an inhibitor of the octadecanoid pathway leading to the biosynthesis of endogeneous jasmonates and some secondary metabolites, phytol and isophytol were increased, while 4-heptenal, 1-dodecanol, and 2-propenoic acid-2-methyl dodecylester were decreased, both of which were negatively correlated with their variations under MeJA treatment. Collectively, these results suggest that MeJA does affect the volatile composition of P. yezoensis, and the octadecanoid pathway together with endogenous jasmonate pathway may be involved in the biosynthesis of volatile compounds, thereby providing some preliminary envision on the composition and biogeneration of volatile compounds in P. yezoensis.

Environmental Aspects of Two Volatile Organic Compound Groundwater Treatment Designs at the Rocky Flats Site - 13135

DOE Office of Scientific and Technical Information (OSTI.GOV)

Michalski, Casey C.; DiSalvo, Rick; Boylan, John

2013-07-01

DOE's Rocky Flats Site in Colorado is a former nuclear weapons production facility that began operations in the early 1950's. Because of releases of hazardous substances to the environment, the federally owned property and adjacent offsite areas were placed on the CERCLA National Priorities List in 1989. The final remedy was selected in 2006. Engineered components of the remedy include four groundwater treatment systems that were installed before closure as CERCLA-accelerated actions. Two of the systems, the Mound Site Plume Treatment System and the East Trenches Plume Treatment System, remove low levels of volatile organic compounds using zero-valent iron media,more » thereby reducing the loading of volatile organic compounds in surface water resulting from the groundwater pathway. However, the zero-valent iron treatment does not reliably reduce all volatile organic compounds to consistently meet water quality goals. While adding additional zero-valent iron media capacity could improve volatile organic compound removal capability, installation of a solar powered air-stripper has proven an effective treatment optimization in further reducing volatile organic compound concentrations. A comparison of the air stripper to the alternative of adding additional zero-valent iron capacity to improve Mound Site Plume Treatment System and East Trenches Plume Treatment System treatment based on several key sustainable remediation aspects indicates the air stripper is also more 'environmentally friendly'. These key aspects include air pollutant emissions, water quality, waste management, transportation, and costs. (authors)« less

Intermediate Volatility Organic Compound Emissions from On-Road Diesel Vehicles: Chemical Composition, Emission Factors, and Estimated Secondary Organic Aerosol Production.

PubMed

Zhao, Yunliang; Nguyen, Ngoc T; Presto, Albert A; Hennigan, Christopher J; May, Andrew A; Robinson, Allen L

2015-10-06

Emissions of intermediate-volatility organic compounds (IVOCs) from five on-road diesel vehicles and one off-road diesel engine were characterized during dynamometer testing. The testing evaluated the effects of driving cycles, fuel composition and exhaust aftertreatment devices. On average, more than 90% of the IVOC emissions were not identified on a molecular basis, instead appearing as an unresolved complex mixture (UCM) during gas-chromatography mass-spectrometry analysis. Fuel-based emissions factors (EFs) of total IVOCs (speciated + unspeciated) depend strongly on aftertreatment technology and driving cycle. Total-IVOC emissions from vehicles equipped with catalyzed diesel particulate filters (DPF) are substantially lower (factor of 7 to 28, depending on driving cycle) than from vehicles without any exhaust aftertreatment. Total-IVOC emissions from creep and idle operations are substantially higher than emissions from high-speed operations. Although the magnitude of the total-IVOC emissions can vary widely, there is little variation in the IVOC composition across the set of tests. The new emissions data are combined with published yield data to investigate secondary organic aerosol (SOA) formation. SOA production from unspeciated IVOCs is estimated using surrogate compounds, which are assigned based on gas-chromatograph retention time and mass spectral signature of the IVOC UCM. IVOCs contribute the vast majority of the SOA formed from exhaust from on-road diesel vehicles. The estimated SOA production is greater than predictions by previous studies and substantially higher than primary organic aerosol. Catalyzed DPFs substantially reduce SOA formation potential of diesel exhaust, except at low speed operations.

Aerosol chemical vapor deposition of metal oxide films

DOEpatents

Ott, Kevin C.; Kodas, Toivo T.

1994-01-01

A process of preparing a film of a multicomponent metal oxide including: forming an aerosol from a solution comprised of a suitable solvent and at least two precursor compounds capable of volatilizing at temperatures lower than the decomposition temperature of said precursor compounds; passing said aerosol in combination with a suitable oxygen-containing carrier gas into a heated zone, said heated zone having a temperature sufficient to evaporate the solvent and volatilize said precursor compounds; and passing said volatilized precursor compounds against the surface of a substrate, said substrate having a sufficient temperature to decompose said volatilized precursor compounds whereby metal atoms contained within said volatilized precursor compounds are deposited as a metal oxide film upon the substrate is disclosed. In addition, a coated article comprising a multicomponent metal oxide film conforming to the surface of a substrate selected from the group consisting of silicon, magnesium oxide, yttrium-stabilized zirconium oxide, sapphire, or lanthanum gallate, said multicomponent metal oxide film characterized as having a substantially uniform thickness upon said FIELD OF THE INVENTION The present invention relates to the field of film coating deposition techniques, and more particularly to the deposition of multicomponent metal oxide films by aerosol chemical vapor deposition. This invention is the result of a contract with the Department of Energy (Contract No. W-7405-ENG-36).

Comparison of two extraction techniques, solid-phase microextraction versus continuous liquid-liquid extraction/solvent-assisted flavor evaporation, for the analysis of flavor compounds in gueuze lambic beer.

PubMed

Thompson-Witrick, Katherine A; Rouseff, Russell L; Cadawallader, Keith R; Duncan, Susan E; Eigel, William N; Tanko, James M; O'Keefe, Sean F

2015-03-01

Lambic is a beer style that undergoes spontaneous fermentation and is traditionally produced in the Payottenland region of Belgium, a valley on the Senne River west of Brussels. This region appears to have the perfect combination of airborne microorganisms required for lambic's spontaneous fermentation. Gueuze lambic is a substyle of lambic that is made by mixing young (approximately 1 year) and old (approximately 2 to 3 years) lambics with subsequent bottle conditioning. We compared 2 extraction techniques, solid-phase microextraction (SPME) and continuous liquid-liquid extraction/solvent-assisted flavor evaporation (CCLE/SAFE), for the isolation of volatile compounds in commercially produced gueuze lambic beer. Fifty-four volatile compounds were identified and could be divided into acids (14), alcohols (12), aldehydes (3), esters (20), phenols (3), and miscellaneous (2). SPME extracted a total of 40 volatile compounds, whereas CLLE/SAFE extracted 36 volatile compounds. CLLE/SAFE extracted a greater number of acids than SPME, whereas SPME was able to isolate a greater number of esters. Neither extraction technique proved to be clearly superior and both extraction methods can be utilized for the isolation of volatile compounds found in gueuze lambic beer. © 2015 Institute of Food Technologists®

Analysis of a GC/MS thermal desorption system with simultaneous sniffing for determination of off-odor compounds and VOCs in fumes formed during extrusion coating of low-density polyethylene.

PubMed

Villberg, K; Veijanen, A

2001-03-01

A thermal desorption equipment introducing volatile organic compounds (VOCs) into the gas chromatographic/ mass spectrometric system (GC/MS) with simultaneous sniffing (SNIFF) is a suitable method for identifying the volatile organic off-odor compounds formed during the extrusion coating process of low-density polyethylene. Fumes emitted during the extrusion coating process of three different plastic materials were collected at two different temperatures (285 and 315 degrees C) from an outgoing pipe and near an extruder. The VOCs of fumes were analyzed by drawing a known volume of air through the adsorbent tube filled with a solid adsorbent (Tenax GR). The air samples were analyzed by using a special thermal desorption device and GC/MS determination. The simultaneous sniffing was carried out to detect off-odors and to assist in the identification of those compounds that contribute to tainting and smelling. The amounts of off-odor carbonyl compounds and the total content of the volatile organic compounds were determined. The most odorous compounds were identified as carboxylic acids while the majority of the volatile compounds were hydrocarbons. The detection and quantification of carboxylic acids were based on the characteristic ions of their mass spectra. The higher the extrusion temperature the more odors were detected. An important observation was that the total concentration of volatiles was dependent not only on the extrusion temperature but also on the plastic material.

Analyzing the flavor compounds in Chinese traditional fermented shrimp pastes by HS-SPME-GC/MS and electronic nose

NASA Astrophysics Data System (ADS)

Fan, Yan; Yin, Li'ang; Xue, Yong; Li, Zhaojie; Hou, Hu; Xue, Changhu

2017-04-01

Shrimp paste is a type of condiments with high nutritional value. However, the flavors of shrimp paste, particularly the non-uniformity flavors, have limited its application in food processing. In order to identify the characteristic flavor compounds in Chinese traditional shrimp pastes, five kinds of typical commercial products were evaluated in this study. The differences in the volatile composition of the five products were investigated. Solid phase micro-extraction method was employed to extract the volatile compounds. GC-MS and electronic nose were applied to identify the compounds, and the data were analyzed using principal component analysis (PCA). A total of 62 volatile compounds were identified, including 8 alcohols, 7 aldehydes, 3 ketones, 7 ethers, 7 acids, 3 esters, 6 hydrocarbons, 12 pyrazines, 2 phenols, and 7 other compounds. The typical volatile compounds contributing to the flavor of shrimp paste were found as follows: dimethyl disulfide, dimethyl tetrasulfide, dimethyl trisulfide, 2, 3, 5-trimethyl-6-ethyl pyrazine, ethyl-2, 5-dimethyl-pyrazine, phenol and indole. Propanoic acid, butanoic acid, furans, and 2-hydroxy-3-pentanone caused unpleasant odors, such as pungent and rancid odors. Principal component analysis showed that the content of volatile compounds varied depending on the processing conditions and shrimp species. These results indicated that the combinations of multiple analysis and identification methods could make up the limitations of a single method, enhance the accuracy of identification, and provide useful information for sensory research and product development.

The Incidence and Fate of Volatile Methyl Siloxanes in a Crewed Spacecraft Cabin

NASA Technical Reports Server (NTRS)

Perry, Jay L.; Kayatin, Matthew J.

2017-01-01

Volatile methyl siloxanes (VMS) arise from diverse, pervasive sources aboard crewed spacecraft ranging from materials offgassing to volatilization from personal care products. These sources lead to a persistent VMS compound presence in the cabin environment that must be considered for robust life support system design. Volatile methyl siloxane compound stability in the cabin environment presents an additional technical issue because degradation products such as dimethylsilanediol (DMSD) are highly soluble in water leading to a unique load challenge for water purification processes. The incidence and fate of VMS compounds as observed in the terrestrial atmosphere, water, and surface (soil) environmental compartments have been evaluated as an analogy for a crewed cabin environment. Volatile methyl siloxane removal pathways aboard crewed spacecraft are discussed and a material balance accounting for a DMSD production mechanism consistent with in-flight observations is presented.

Gas-liquid chromatography in lunar organic analysis.

NASA Technical Reports Server (NTRS)

Gehrke, C. W.

1972-01-01

Gas-liquid chromatography (GLC) is a powerful and sensitive method for the separation and detection of organic compounds at nanogram levels. The primary requirement for successful analyses is that the compounds of interest must be volatile under the chromatographic conditions employed. Nonvolatile organic compounds must be converted to volatile derivatives prior to analysis. The derivatives of choice must be both amenable to chromatographic separation and be relatively stable. The condition of volatility necessitates the development of efficient derivatization reactions for important groups of compounds as amino acids, carbohydrates, nucleosides, etc. Trimethylsilylation and trifluoroacetylation represent specific areas of recent prominence. Some relevant practical aspects of GLC are discussed.

Migration from polyamide 'microwave and roasting bags' into roast chicken.

PubMed

Gramshaw, J W; Soto-Valdez, H

1998-04-01

Migration of non-volatile and volatile compounds from 'microwave and roasting bags' (MRB), made of Nylon 6,6 (and some Nylon 6), into chicken meat, skin, and juices during roasting (200 degrees C/2 h) in a conventional oven was determined. For measurement of migration of non-volatile compounds, cooked chicken was freeze-dried, extracted with methanol after addition of 2-azacyclononane (internal standard) and the extract cleaned-up using liquid-solid adsorption chromatography (silica gel). High performance liquid chromatography (HPLC) in the reverse phase mode using a linear gradient of methanol in water was used to quantify seven Nylon 6 and Nylon 6,6 cyclic monomers and oligomers of molecular mass up to 678 daltons. Migration into chicken was 7.48 micrograms/g (8.26 mg/bag; 3.94 micrograms/cm2), 16% of the total non-volatile compounds contained in the MRB material. Individual migrants were also quantified. Migration of one volatile compound, 2-cyclopentyl cyclopentanone, into the roast chicken parts was measured. Extraction with diethyl ether, using a modified Likens-Nickerson system of concurrent steam distillation-solvent extraction with an internal standard (cyclohexanone) was performed for 10 h. Gas chromatography/mass spectrometry (GC/MS) in the selected ion mode (SIM) was used for quantification. An average of 14.0 (+/- 4.36) micrograms/bag (or micrograms/chicken) migrated, being 0.08% of the total 2-cyclopentyl cyclopentanone present in MRB. Loss of volatile compounds to the atmosphere is believed to have occurred since there was another, more volatile compound (cyclopentanone), present in MRB, at levels higher than 2-cyclopentyl cyclopentanone, but this was not detected in roast chicken. In general, the transference of MRB components into roast chicken can be considered not to present a hazard.

Emission of Volatile Compounds from Apple Plants Infested with Pandemis heparana Larvae, Antennal Response of Conspecific Adults, and Preliminary Field Trial.

PubMed

Giacomuzzi, Valentino; Cappellin, Luca; Khomenko, Iuliia; Biasioli, Franco; Schütz, Stefan; Tasin, Marco; Knight, Alan L; Angeli, Sergio

2016-12-01

This study investigated the volatile emission from apple (Malus x domestica Borkh., cv. Golden Delicious) foliage that was either intact, mechanically-damaged, or exposed to larval feeding by Pandemis heparana (Denis and Schiffermüller) (Lepidoptera: Tortricidae). Volatiles were collected by closed-loop-stripping-analysis and characterized by gas chromatography-mass spectrometry in three time periods: after 1 h and again 24 and 48 h later. Volatiles for all treatments also were monitored continuously over a 72-h period by the use of proton transfer reaction - time of flight-mass spectrometry (PTR-ToF-MS). In addition, the volatile samples were analyzed by gas chromatography-electroantennographic detection (GC-EAD) using male and female antennae of P. heparana. Twelve compounds were detected from intact foliage compared with 23 from mechanically-damaged, and 30 from P. heparana-infested foliage. Interestingly, six compounds were released only by P. heparana-infested foliage. The emission dynamics of many compounds measured by PTR-ToF-MS showed striking differences according to the timing of herbivory and the circadian cycle. For example, the emission of green leaf volatiles began shortly after the start of herbivory, and increased over time independently from the light-dark cycle. Conversely, the emission of terpenes and aromatic compounds showed a several-hour delay in response to herbivory, and followed a diurnal rhythm. Methanol was the only identified volatile showing a nocturnal rhythm. Consistent GC-EAD responses were found for sixteen compounds, including five aromatic ones. A field trial in Sweden demonstrated that benzyl alcohol, 2-phenylethanol, phenylacetonitrile, and indole lures placed in traps were not attractive to Pandemis spp. adults, but 2-phenylethanol and phenylacetonitrile when used in combination with acetic acid were attractive to both sexes.

The micro-environmental impact of volatile organic compound emissions from large-scale assemblies of people in a confined space

USDA-ARS?s Scientific Manuscript database

Large-scale assemblies of people in a con'ned space can exert signi'cant impacts on the local air chemistry due to human emissions of volatile organics. Variations of air-quality in such small scale can be studied by quantifying 'ngerprint volatile organic compounds (VOCs) such as acetone, toluene, ...

‘Fuji’ apple (Malus domestica Borkh) volatile production during high pCO2 controlled atmosphere storage

USDA-ARS?s Scientific Manuscript database

‘Fuji’apple [Malus sylvestris var. domestica (Borkh.) Mansf.] volatile compound dynamics were characterized during cold storage in air or at low pO2 controlled atmosphere (CA) with up to 5 kPa CO2. Volatile compounds in storage chambers were adsorbed onto solid sorbent traps and analyzed by GC-MS....

Cold oceans enhance terrestrial new-particle formation in near-coastal forests

NASA Astrophysics Data System (ADS)

Suni, T.; Sogacheva, L.; Lauros, J.; Hakola, H.; Bäck, J.; Kurtén, T.; Cleugh, H.; van Gorsel, E.; Briggs, P.; Sevanto, S.; Kulmala, M.

2009-06-01

The world's forests produce atmospheric aerosol by emitting volatile organic compounds (VOC) which, after being oxidized in the atmosphere, readily condense on the omnipresent nanometer-sized nuclei and grow them to climatically relevant sizes. The cooling effect of aerosols is the greatest uncertainty in current climate models and estimates of radiative forcing. Therefore, identifying the environmental factors influencing the biogenic formation of aerosols is crucial. We show that, in addition to local meteorological factors in the forest, the magnitude of evaporation from oceans hundreds of kilometers upwind can effectively suppress or enhance new-particle formation. Our findings indicate that, unlike warm waters, the cold polar oceans provide excellent clean and dry background air that enhances aerosol formation above near-coastal forests in Fennoscandia and South-East Australia.

Soil sampling kit and a method of sampling therewith

DOEpatents

Thompson, Cyril V.

1991-01-01

A soil sampling device and a sample containment device for containing a soil sample is disclosed. In addition, a method for taking a soil sample using the soil sampling device and soil sample containment device to minimize the loss of any volatile organic compounds contained in the soil sample prior to analysis is disclosed. The soil sampling device comprises two close fitting, longitudinal tubular members of suitable length, the inner tube having the outward end closed. With the inner closed tube withdrawn a selected distance, the outer tube can be inserted into the ground or other similar soft material to withdraw a sample of material for examination. The inner closed end tube controls the volume of the sample taken and also serves to eject the sample. The soil sample containment device has a sealing member which is adapted to attach to an analytical apparatus which analyzes the volatile organic compounds contained in the sample. The soil sampling device in combination with the soil sample containment device allow an operator to obtain a soil sample containing volatile organic compounds and minimizing the loss of the volatile organic compounds prior to analysis of the soil sample for the volatile organic compounds.

Soil sampling kit and a method of sampling therewith

DOEpatents

Thompson, C.V.

1991-02-05

A soil sampling device and a sample containment device for containing a soil sample is disclosed. In addition, a method for taking a soil sample using the soil sampling device and soil sample containment device to minimize the loss of any volatile organic compounds contained in the soil sample prior to analysis is disclosed. The soil sampling device comprises two close fitting, longitudinal tubular members of suitable length, the inner tube having the outward end closed. With the inner closed tube withdrawn a selected distance, the outer tube can be inserted into the ground or other similar soft material to withdraw a sample of material for examination. The inner closed end tube controls the volume of the sample taken and also serves to eject the sample. The soil sample containment device has a sealing member which is adapted to attach to an analytical apparatus which analyzes the volatile organic compounds contained in the sample. The soil sampling device in combination with the soil sample containment device allows an operator to obtain a soil sample containing volatile organic compounds and minimizing the loss of the volatile organic compounds prior to analysis of the soil sample for the volatile organic compounds. 11 figures.

Analysis of selected volatile organic compounds at background level in South Africa.

NASA Astrophysics Data System (ADS)

Ntsasa, Napo; Tshilongo, James; Lekoto, Goitsemang

2017-04-01

Volatile organic compounds (VOC) are measured globally at urban air pollution monitoring and background level at specific locations such as the Cape Point station. The urban pollution monitoring is legislated at government level; however, the background levels are scientific outputs of the World Meteorological Organisation Global Atmospheric Watch program (WMO/GAW). The Cape Point is a key station in the Southern Hemisphere which monitors greenhouse gases and halocarbons, with reported for over the past decade. The Cape Point station does not have the measurement capability VOC's currently. A joint research between the Cape Point station and the National Metrology Institute of South Africa (NMISA) objective is to perform qualitative and quantitative analysis of volatile organic compounds listed in the GAW program. NMISA is responsible for development, maintain and disseminate primary reference gas mixtures which are directly traceable to the International System of Units (SI) The results of some volatile organic compounds which where sampled in high pressure gas cylinders will be presented. The analysis of samples was performed on the gas chromatography with flame ionisation detector and mass selective detector (GC-FID/MSD) with a dedicate cryogenic pre-concentrator system. Keywords: volatile organic compounds, gas chromatography, pre-concentrator

HS-SPME analysis of volatile organic compounds of coniferous needle litter

NASA Astrophysics Data System (ADS)

Isidorov, V. A.; Vinogorova, V. T.; Rafałowski, K.

The composition of volatile emission of Scots pine ( Pinus sylvestris) and spruce ( Picea exelsa) litter was studied by gas chromatography-mass spectrometry (GC-MS) and samples were collected by solid-phase microextraction (SPME) method. The list of identified compounds includes over 60 organic substances of different classes. It was established that volatile emission contain not only components of essential oils of pine and spruce needles but also a large number of organic compounds which are probably secondary metabolites of litter-decomposing fungi. They include lower carbonyl compounds and alcohols as well as products of terpene dehydration and oxidation. These data show that the processes of litter decomposition are an important source of reactive organic compounds under canopy of coniferous forests.