Sample records for volatile organic acids

  1. VOC (VOLATILE ORGANIC COMPOUND EMISSION FACTORS FOR THE NAPAP (NATIONAL ACID PRECIPITATION ASSESSMENT PROGRAM) EMISSION INVENTORY

    EPA Science Inventory

    The report gives results of the generation of emission factors for volatile organic compound (VOC) emissions for a number of source classification categories (SCCs), as part of the National Acid Precipitation Assessment Program (NAPAP). Each SCC represents a process or function t...

  2. Exposure to Wood Dust, Resin Acids, and Volatile Organic Compounds During Production of Wood Pellets

    Microsoft Academic Search

    Katja Hagström; Sara Axelsson; Helena Arvidsson; Ing-Liss Bryngelsson; Cecilia Lundholm; Kåre Eriksson

    2008-01-01

    The main aim of this study was to investigate exposure to airborne substances that are potentially harmful to health during the production of wood pellets, including wood dust, monoterpenes, and resin acids, and as an indicator of diesel exhaust nitrogen dioxide. In addition, area measurements were taken to assess background exposure levels of these substances, volatile organic compounds (VOCs), and

  3. Determination of Organic Acids and Volatile Flavor Substances in Kefir during Fermentation

    Microsoft Academic Search

    Z. B. Güzel-Seydim; A. C. Seydim; A. K. Greene; A. B. Bodine

    2000-01-01

    The production of organic acids and volatile flavor components was measured during kefir starter culture fermentation. Samples were collected at 0, 5, 10, 15, and 22 h of fermentation (final pH=4.6). Samples were analyzed for orotic, citric, pyruvic, uric, lactic, acetic, butyric, propionic and hippuric acids by HPLC. Acetaldehyde, ethanol, acetoin and diacetyl production were monitored using GC equipped with

  4. Volatile organic acids and microbial processes in the Yegua formation, east-central Texas 

    E-print Network

    Routh, J.; Grossman, E. L.; Ulrich, G. A.; Suflita, J. M.

    2000-01-01

    intermediate in these processes, serving as a substrate for SO 4 reducing bacteria (SRB) and methanogens (Sansone and Mar- tens, 1982). Volatile organic acids such as acetic, propionic, iso- butyric, n-butyric, iso-valeric, and n-valeric acids are Applied..., 1984). In reducing environments such as those of the Atlantic Coastal Plain aquifers and shal- low marine sediments, SRB and methanogens consume the fermentation products (McMahon and Chapelle, 1991; Novelli et al., 1988). McMahon and Chapelle (1991...

  5. Measurements of Volatile Organic Compounds and Gaseous Sulfuric Acid During the 2008 CAREBEIJING Campaign

    NASA Astrophysics Data System (ADS)

    Zhang, R.; Zheng, J.; Hu, M.; Zhu, T.

    2009-05-01

    Air quality in Beijing has been a hot topic recently, because Beijing hosted the 2008 summer Olympics. To combat the problem, China ordered numerous factories shut down or used only sporadically during the games to limit air pollution in the area. Another major step involved ordering about one-half of the city's 3.3 million vehicles off the road during the games, allowing only cars on roads with odd or even-numbered license plates on alternate days until the games were over. In addition, China has implemented new auto emission standards since March 2009 with regulations that are similar to those used throughout Europe. Our team at the Texas A&M participated in the 2008 CAREBEIJING campaign, with the objectives of studying the complex chemistry of the air in Beijing, looking at emission controls and their effectiveness, studying the surrounding air from other regions and how it can affect Beijing's air, and comparing all of our findings with air quality in other cities we have examined, such as Mexico City and Houston. In this talk, preliminary results of measurements of volatile organic compounds (VOCs) and gaseous sulfuric acid will be presented to discuss the trends of VOCs and new particle formation associated with the traffic control.

  6. Comparative evaluation of volatiles, phenolics, sugars, organic acids and antioxidant properties of Sel-42 and Tainung papaya varieties.

    PubMed

    Kelebek, Hasim; Selli, Serkan; Gubbuk, Hamide; Gunes, Esma

    2015-04-15

    The present study was designed to determine the phenolic compounds, organic acids, sugars, aroma profiles and antioxidant properties of Sel-42 and Tainung papayas grown in Turkey. High-performance liquid chromatography/electrospray ionisation tandem mass spectrometry (HPLC-ESI-MS/MS) method was used for the phenolic compounds analysis. Twelve phenolic compounds were identified and quantified in the samples. The total phenolic content of Sel-42 was clearly higher than that of Tainung. Protocatechuic acid-hexoside, gallic acid-deoxyhexoside, ferulic acid and chlorogenic acids were the most abundant phenolics in both cultivars. Aroma composition of papaya was analysed by gas chromatography-mass spectrometry (GC-MS). A total of 46 and 42 aroma compounds, including esters, alcohols, terpenes, lactones, acids, carbonyl compounds, and volatile phenols were identified in the Sel-42 and Tainung, respectively. The significant linear correlation was confirmed between the values for the total phenolic content and antioxidant activity of papaya extracts. PMID:25466106

  7. Determination of volatile organic acids in tobacco by single-drop microextraction with in-syringe derivatization followed by GC-MS.

    PubMed

    Sha, Yunfei; Meng, Jiaoran; Zhang, Yichun; Deng, Chunhui; Wu, Da

    2010-02-01

    In this work, the novel technique based on headspace single-drop microextraction with in-syringe derivatization followed by GC-MS was established to determine the volatile organic acids in tobacco. The parameters for headspace single-drop microextraction and in-syringe derivatization were optimized, including extraction time, and volume of derivatization reagent and in-syringe derivatization time. The method validations including linearity, precision, recovery and LOD were also studied. The obtained results illustrated that the optimized technique was easy, highly efficient and sensitive. Finally, the proposed method was successfully applied to the analyses of volatile organic acids in tobacco samples with seven different brands. It was further demonstrated that the present technique developed in this study does offer a simple and fast approach to determine volatile organic acids in tobacco. PMID:20039308

  8. SCREENING FOR VOLATILE ORGANIC FATTY ACIDS IN AGRICULTURAL AIR USING SOLID-PHASE MICROEXTRACTION AND GAS CHROMATOGRAPHY-MASS SPECTROMETRY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Volatile fatty acids (VFAs) are a major component of odorous gases associated with agricultural sources. Because of typically low VFA air concentrations, conventional air sampling methods including sorbent tubes and vacuum canisters are often not sensitive enough to detect them. Solid phase microe...

  9. Regeneration of carboxylic acid-laden basic sorbents by leaching with a volatile base in an organic solvent

    DOEpatents

    King, C. Judson (Kensington, CA); Husson, Scott M. (Berkeley, CA)

    1999-01-01

    Carboxylic acids are sorbed from aqueous feedstocks onto a solid adsorbent. The acids are freed from the sorbent phase by treating it with an organic solution of alkylamine thus forming an alkylamine/carboxylic acid complex which is decomposed with improved efficiency to the desired carboxylic acid and the alkylamine. Carbon dioxide addition can be used to improve the adsorption or the carboxylic acids by the solid phase sorbent.

  10. 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...

  11. Volatile organic compound sensor system

    DOEpatents

    Schabron, John F.; Rovani, Jr., Joseph F.; Bomstad, Theresa M.; Sorini-Wong, Susan S.; Wong, Gregory K.

    2011-03-01

    Generally, this invention relates to the development of field monitoring methodology for new substances and sensing chemical warfare agents (CWAs) and terrorist substances. It also relates to a portable test kit which may be utilized to measure concentrations of halogenated volatile organic compounds (VOCs) in the field. Specifically it relates to systems for reliably field sensing the potential presence of such items while also distinguishing them from other elements potentially present. It also relates to overall systems and processes for sensing, reacting, and responding to an indicated presence of such substance, including modifications of existing halogenated sensors and arrayed sensing systems and methods.

  12. Volatile organic compound sensor system

    DOEpatents

    Schabron, John F. (Laramie, WY); Rovani, Jr., Joseph F. (Laramie, WY); Bomstad, Theresa M. (Laramie, WY); Sorini-Wong, Susan S. (Laramie, WY)

    2009-02-10

    Generally, this invention relates to the development of field monitoring methodology for new substances and sensing chemical warfare agents (CWAs) and terrorist substances. It also relates to a portable test kit which may be utilized to measure concentrations of halogenated volatile organic compounds (VOCs) in the field. Specifically it relates to systems for reliably field sensing the potential presence of such items while also distinguishing them from other elements potentially present. It also relates to overall systems and processes for sensing, reacting, and responding to an indicated presence of such substance, including modifications of existing halogenated sensors and arrayed sensing systems and methods.

  13. THE LACTIC ACID AND VOLATILE FATTY ACID CONTENT AND IN VITRO ORGANIC MATTER DIGESTIBILITY OF SILAGES MADE FROM POTATO PROCESSING RESIDUES AND BARLEY STRAW 1

    Microsoft Academic Search

    E. A. Sauter; D. D. Hinman; J. F. Parkinson

    2010-01-01

    Summary In vitro organic matter digestibility (IVOMD) of silages made from potato processing residues (PPR) and barley straw was studied in two replicated experiments using a split-block design. Lactic acid content as well as acetic, propionic and butyric acid (VFA) levels of silages were determined. Silages were made from either filter cake (FC), dry peel (DP) or a mixture of

  14. Biodiversity of volatile organic compounds from five French ferns.

    PubMed

    Fons, Françoise; Froissard, Didier; Bessière, Jean-Marie; Buatois, Bruno; Rapior, Sylvie

    2010-10-01

    Five French ferns belonging to different families were investigated for volatile organic compounds (VOC) by GC-MS using organic solvent extraction. Fifty-five VOC biosynthesized from the shikimic, lipidic and terpenic pathways including monoterpenes, sesquiterpenes and carotenoid-type compounds were identified. The main volatile compound of Adiantum capillus-veneris L. (Pteridaceae) was (E)-2-decenal with a plastic or "stink bug" odor. The volatile profiles of Athyrium filix-femina (L.) Roth (Woodsiaceae) and Blechnum spicant (L.) Roth (Blechnaceae) showed similarities, with small amounts of isoprenoids and the same main volatile compounds, i.e., 2-phenylethanal (odor of lilac and hyacinth) and 1-octen-3-ol (mushroom-like odor). The main volatile compound of Dryopteris filix-mas (L.) Schott (Dryopteridaceae) was (E)-nerolidol with a woody or fresh bark note. Polyketides, as acylfilicinic acids, were mainly identified in this fern. Oreopteris limbosperma (Bellardi ex. All.) J. Holub (Thelypteridaceae), well-known for its lemon smell, contained the highest biodiversity of VOC. Eighty percent of the volatiles was issued from the terpenic pathway. The main volatiles were (E)-nerolidol, alpha-terpineol, beta-caryophyllene and other minor monoterpenes (for example, linalool, pinenes, limonene, and gamma-terpinen-7-al). It was also the fern with the highest number of carotenoid-type derivatives, which were identified in large amounts. Our results were of great interest underlying new industrial valorisation for ferns based on their broad spectrum of volatiles. PMID:21121267

  15. VOLATILE ORGANIC ANALYSIS BY DIRECT AQUEOUS INJECTION

    EPA Science Inventory

    Gas chromatographic environmental analysis by direct aqueous injection (DAI) was studied for 24 volatile organic analytes (VOAs). Internal standardization was used to determine the precision of analyzing these compounds by DAI. Aequous samples were directly introduced to a gas ch...

  16. TOXIC ORGANIC VOLATILIZATION FROM LAND TREATMENT SYSTEMS

    EPA Science Inventory

    Methodology was evaluated for estimating volatilization of toxic organic chemicals from unsaturated soils. Projections were compared with laboratory data for simulated rapid infiltration wastewater treatment systems receiving primary municipal wastewater spiked with a suite of 18...

  17. VOLATILE ORGANIC COMPOUNDS AS EXPOSURE BIOMARKERS

    EPA Science Inventory

    Alveolar breath sampling and analysis can be extremely useful in exposure assessment studies involving volatile organic compounds (VOCs). Over recent years scientists from the US Environmental Protection Agency's National Exposure Research Laboratory have developed and refined...

  18. Photosynthetic hydrogen evolution with volatile organic acids derived from the fermentation of source selected municipal solid wastes

    Microsoft Academic Search

    E. Fascetti; E. D'Addario; O. Todini; A. Robertiello

    1998-01-01

    Rhodobacter sphaeroides RV cells were cultivated on lactate containing solutions derived from the acidogenesis of source selected municipal solid wastes. Cells were also used for the phototrophic hydrogen evolution using the same substrate. Batch-wise and continuous experiments showed that the acidic aqueous stream obtained from such refuse is quite a good substrate for the growth of R. sphaeroides RV without

  19. Analyzing method on biogenic volatile organic compounds

    NASA Astrophysics Data System (ADS)

    Bai, J. H.; Wang, M. X.; Hu, F.; Greenberg, J. P.; Guenther, A. B.

    2002-02-01

    In order to analyze biogenic volatile organic compounds in the atmosphere, an automated gas chromatography is developed and employed at the laboratory of National Center for Atmospheric Research (NCAR) during January to July, 2000. A small refrigerator was used so as to remove water in the air sample from gas line, and get accurate concentrations of volatile organic compounds. At 5degreesC, good water removing efficiency can be obtained at controlled flow rate. Air samples were collected around the building of Mesa Lab. of NCAR and analyzed by this gas chromatography system. This paper reports this gas chromatography system and results of air samples. The experimental results show that this gas chromatography system has a good reproducibility and stability, and main interesting volatile organic compounds such as isoprene, monoterpenes have an evident diurnal variation.

  20. 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.

  1. Chronic effect of cadmium in sediments on colonization by benthic marine organisms: An evaluation of the role of interstitial cadmium and acid-volatile sulfide in biological availability

    Microsoft Academic Search

    David J. Hansen; W. J. Berry; S. J. Benyi; J. D. Mahony; Jeffrey M. Corbin; Sheldon D. Pratt; Dominic M. Di Toro; Mary Beth Abel

    1996-01-01

    The role of interstitial cadmium and acid-volatile sulfide (AVS) in controlling the bioavailability of sediment-associated metal was examined using the chronic saltwater benthic colonization test. Sediments were spiked to achieve nominal cadmium\\/AVS molar ratios of 0.0 (control), 0.1, 0.8, and 3.0 in this 118-d test. Oxidation of AVS in the surficial 2.4 cm within 2 to 4 weeks resulted in

  2. Analysis of volatile organic compounds. [trace amounts of organic volatiles in gas samples

    NASA Technical Reports Server (NTRS)

    Zlatkis, A. (inventor)

    1977-01-01

    An apparatus and method are described for reproducibly analyzing trace amounts of a large number of organic volatiles existing in a gas sample. Direct injection of the trapped volatiles into a cryogenic percolum provides a sharply defined plug. Applications of the method include: (1) analyzing the headspace gas of body fluids and comparing a profile of the organic volatiles with standard profiles for the detection and monitoring of disease; (2) analyzing the headspace gas of foods and beverages and comparing the profile with standard profiles to monitor and control flavor and aroma; and (3) analyses for determining the organic pollutants in air or water samples.

  3. 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...

  4. VOLATILE ORGANIC SAMPLING TRAIN - SOOT INTERFERENCE REPORT

    EPA Science Inventory

    The U.S. Environmental Protection Agency uses Method 0030, the Volatile Organic Sampling Train (VOST), as a tool in determining the destruction and removal efficiencies of industrial boilers co-firing hazardous waste. ecently, concerns have been expressed over possible measuremen...

  5. Emerging Control Technologies for Volatile Organic Compounds

    Microsoft Academic Search

    Geeta Rani Parmar; N. N. Rao

    2008-01-01

    Environmental problems associated with volatile organic compounds (VOCs) in the atmosphere have provided the driving force for sustained fundamental and applied research in the area of environmental remediation. Conventional methods currently used to treat VOCs include incineration, condensation, adsorption, and absorption. Incineration and condensation are cost-effective only for moderate to high VOC concentrations. Adsorption and absorption do not destroy VOCs

  6. Ozone Production Potential of Volatile Organic Compounds

    Microsoft Academic Search

    T. Butler; M. G. Lawrence; J. Lelieveld

    2010-01-01

    Calculation of the ozone production potential of Volatile Organic Compounds (VOC) has traditionally been performed using so-called incremental reactivity techniques. Here were present a new approach to this problem using a photochemical box model with a tagged chemical mechanism. The results of our approach are consistent with previous work, but deliver much more detailed information about the VOC intermediate oxidation

  7. 77 FR 52606 - Approval and Promulgation of Air Quality Implementation Plans; Indiana; Volatile Organic...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-30

    ...recordkeeping requirements, Volatile organic compounds. Dated: August 14, 2012...new entry in ``Article 8. Volatile Organic Compound Rules'' for ``Rule 14. Architectural...Article 8. Volatile Organic Compound...

  8. 40 CFR 60.392 - Standards for volatile organic compounds

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Standards for volatile organic compounds 60.392 Section 60...Standards of Performance for Automobile and Light Duty Truck Surface Coating Operations § 60.392 Standards for volatile organic compounds On and after...

  9. 40 CFR 60.392 - Standards for volatile organic compounds

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Standards for volatile organic compounds 60.392 Section 60...Standards of Performance for Automobile and Light Duty Truck Surface Coating Operations § 60.392 Standards for volatile organic compounds On and after...

  10. 40 CFR 60.392 - Standards for volatile organic compounds

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Standards for volatile organic compounds 60.392 Section 60...Standards of Performance for Automobile and Light Duty Truck Surface Coating Operations § 60.392 Standards for volatile organic compounds On and after...

  11. 21 CFR 573.914 - Salts of volatile fatty acids.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2012-04-01 false Salts of volatile fatty acids. 573.914... Food Additive Listing § 573.914 Salts of volatile fatty acids. (a) Identity...blend containing the ammonium or calcium salt of isobutyric acid and the ammonium...

  12. 21 CFR 573.914 - Salts of volatile fatty acids.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Salts of volatile fatty acids. 573.914... Food Additive Listing § 573.914 Salts of volatile fatty acids. (a) Identity...blend containing the ammonium or calcium salt of isobutyric acid and the ammonium...

  13. 21 CFR 573.914 - Salts of volatile fatty acids.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Salts of volatile fatty acids. 573.914... Food Additive Listing § 573.914 Salts of volatile fatty acids. (a) Identity...blend containing the ammonium or calcium salt of isobutyric acid and the ammonium...

  14. 21 CFR 573.914 - Salts of volatile fatty acids.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 false Salts of volatile fatty acids. 573.914 Section 573.914 Food... § 573.914 Salts of volatile fatty acids. (a) Identity. The food additive...the ammonium or calcium salt of isobutyric acid and the ammonium or calcium salts of...

  15. 21 CFR 573.914 - Salts of volatile fatty acids.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 false Salts of volatile fatty acids. 573.914 Section 573.914 Food... § 573.914 Salts of volatile fatty acids. (a) Identity. The food additive...the ammonium or calcium salt of isobutyric acid and the ammonium or calcium salts of...

  16. Volatile organic carbon/air separation test using gas membranes

    SciTech Connect

    King, C.V.; Kaschemekat, J.

    1993-08-01

    An estimated 900 metric tons of carbon tetrachloride were discharged to soil columns during the Plutonium Finishing Plant Operations at the Hanford Site. The largest percentage of this volatile organic compound was found in the vadose region of the 200 West Area. Using a Vacuum Extraction System, the volatile organic compound was drawn from the soil in an air mixture at a concentration of about 1,000 parts per million. The volatile organic compounds were absorbed from the air stream using granulated activated carbon canisters. A gas membrane separation system, developed by Membrane Technology and Research, Inc., was tested at the Vacuum Extraction System site to determine if the volatile organic compound load on the granulated activated carbon could be reduced. The Vacuum Extraction System condensed most of the volatile organic compound into liquid carbon tetrachloride and vented the residual gas stream into the granulated activated carbon. This system reduced the cost of operation about $5/kilogram of volatile organic compound removed.

  17. FIELD SCREENING FOR HALOGENATED VOLATILE ORGANIC COMPOUNDS

    SciTech Connect

    John F. Schabron; Joseph F. Rovani Jr.; Theresa M. Bomstad

    2002-06-01

    Western Research Institute (WRI) initiated exploratory work towards the development of new field screening methodology and a test kit to measure halogenated volatile organic compounds (VOCs) in the field. Heated diode and corona discharge sensors are commonly used to detect leaks of refrigerants from air conditioners, freezers, and refrigerators. They are both selective to the presence of carbon-halogen bonds. Commercially available heated diode and corona discharge leak detectors were procured and evaluated for halogenated VOC response. The units were modified to provide a digital readout of signal related to VOC concentration. Sensor response was evaluated with carbon tetrachloride and tetrachloroethylene (perchloroethylene, PCE), which represent halogenated VOCs with and without double bonds. The response characteristics were determined for the VOCs directly in headspace in Tedlar bag containers. Quantitation limits in air were estimated. Potential interferences from volatile hydrocarbons, such as toluene and heptane, were evaluated. The effect of humidity was studied also. The performance of the new devices was evaluated in the laboratory by spiking soil samples and monitoring headspace for halogenated VOCs. A draft concept of the steps for a new analytical method was outlined. The results of the first year effort show that both devices show potential utility for future analytical method development work towards the goal of developing a portable test kit for screening halogenated VOCs in the field.

  18. Volatile organic monitor for industrial effluents

    SciTech Connect

    Laguna, G.R.; Peter, F.J.; Stuart, A.D.; Loyola, V.M.

    1993-07-01

    1990 amendments to the Clean Air Act have created the need for instruments capable of monitoring volatile organic compounds (VOCS) in public air space in an unattended and low cost manner. The purpose of the study was to develop and demonstrate the capability to do long term automatic and unattended ambient air monitoring using an inexpensive portable analytic system at a commercial manufacturing plant site. A gas chromatograph system personal computer hardware, meteorology tower & instruments, and custom designed hardware and software were developed. Comparison with an EPA approved method was performed. The system was sited at an aircraft engines manufacturing site and operated in a completely unattended mode for 60 days. Two VOCs were monitored every 30 minutes during the 24hr day. Large variation in the concentration from 800ppb to the limits of detection of about 10ppb were observed. Work to increase the capabilities of the system is ongoing.

  19. Fatty Acid Composition and Volatile Constituents of Protaetia brevitarsis Larvae

    PubMed Central

    Yeo, Hyelim; Youn, Kumju; Kim, Minji; Yun, Eun-Young; Hwang, Jae-Sam; Jeong, Woo-Sik; Jun, Mira

    2013-01-01

    A total of 48 different volatile oils were identified form P. brevitarsis larvae by gas chromatography/mass spectrometry (GC/MS). Acids (48.67%) were detected as the major group in P. brevitarsis larvae comprising the largest proportion of the volatile compounds, followed by esters (19.84%), hydrocarbons (18.90%), alcohols (8.37%), miscellaneous (1.71%), aldehydes (1.35%) and terpenes (1.16%). The major volatile constituents were 9-hexadecenoic acid (16.75%), 6-octadecenoic acid (14.88%) and n-hexadecanoic acid (11.06%). The composition of fatty acid was also determined by GC analysis and 16 fatty acids were identified. The predominant fatty acids were oleic acid (C18:1, 64.24%) followed by palmitic acid (C16:0, 15.89%), palmitoleic acid (C16:1, 10.43%) and linoleic acid (C18:2, 4.69%) constituting more than 95% of total fatty acids. The distinguished characteristic of the fatty acid profile of P. brevitarsis larvae was the high proportion of unsaturated fatty acid (80.54% of total fatty acids) versus saturated fatty acids (19.46% of total fatty acids). Furthermore, small but significant amounts of linoleic, linolenic and ?-linolenic acids bestow P. brevitarsis larvae with considerable nutritional value. The novel findings of the present study provide a scientific basis for the comprehensive utilization of the insect as a nutritionally promising food source and a possibility for more effective utilization. PMID:24471125

  20. PROTOCOL FOR THE COLLECTION AND ANALYSIS OF VOLATILE POHCS (PRINCIPAL ORGANIC HAZARDOUS CONSTITUENTS) USING VOST (VOLATILE ORGANIC SAMPLING TRAIN)

    EPA Science Inventory

    The document is a state-of-the-art operating protocol for sampling and analysis of volatile organic constituents of flue gas from hazardous waste incinerators or other similar combustor systems using the Volatile Organic Sampling Train (VOST). It is intended to be used for guidan...

  1. Chronic effect of cadmium in sediments on colonization by benthic marine organisms: An evaluation of the role of interstitial cadmium and acid-volatile sulfide in biological availability

    SciTech Connect

    Hansen, D.J.; Berry, W.J.; Benyi, S.J. [Environmental Protection Agency, Narragansett, RI (United States); Mahony, J.D. [Manhattan Coll., New York, NY (United States). Dept. of Environmental Engineering; Corbin, J.M. [Texas Natural Resource Conservation Commission, Austin, TX (United States). Environmental Assessment Div.; Pratt, S.D. [Univ. of Rhode Island, Narragansett, RI (United States). Graduate School of Oceanography; Toro, D.M. di [Manhattan Coll., New York, NY (United States). Dept. of Environmental Engineering]|[HydroQual, Inc., Mahwah, NJ (United States); Abel, M.B. [Univ. of Rhode Island, Kingston, RI (United States). Botany Dept.

    1996-12-01

    The role of interstitial cadmium and acid-volatile sulfide (AVS) in controlling the bioavailability of sediment-associated metal was examined using the chronic saltwater benthic colonization test. Sediments were spiked to achieve nominal cadmium/AVS molar ratios of 0.0 (control), 0.1, 0.8, and 3.0 in this 118-d test. Oxidation of AVS in the surficial 2.4 cm within 2 to 4 weeks resulted in sulfide profiles similar to those occurring naturally in local sediments. In the nominal 0.1 cadmium/AVS treatment measured simultaneously extracted metal (SEM{sub Cd}) was always less than AVS. Interstitial cadmium concentrations were less than those likely to cause biological effects. No significant biological effects were detected. In the nominal 0.8 cadmium/AVS treatment, measured SEM{sub Cd} commonly exceeded AVS in the surficial 2.4 cm of sediment. Interstitial cadmium concentrations were of likely toxicological significance to highly sensitive species. Shifts in the presence or absence over all taxa, and fewer macrobenthic polychaetes (Mediomastus ambiseta, Streblospio benedicti, and Podarke obscurea) and unidentified meiofaunal nematodes, were observed. In the nominal 3.0 cadmium/AVS treatment, concentrations of SEM{sub Cd} were always greater than AVS throughout the sediment column. Interstitial cadmium ranged from 28,000 to 174,000 {micro}g/L. In addition to the effects above, the sediments were colonized by fewer macrobenthic species, polychaete species, and harpacticoids; had lower densities of diatoms; lacked bivalve molluscs; and exhibited other impacts. Over all treatments, the observed biological responses were consistent with SEM{sub Cd}/AVS ratios in surficial sediments and interstitial water cadmium concentrations.

  2. Effect of cadmium in sediments on colonization by benthic marine organisms: Role of interstitial cadmium and acid volatile sulfide in bioavailability

    SciTech Connect

    Hansen, D.; Berry, W.; Benyi, S. [Environmental Protection Agency, Narragansett, RI (United States); Mahony, J. [Manhattan College, Riverdale, NY (United States); Corbin, J. [TNRCC, Austin, TX (United States); Pratt, S.; Able, M. [Univ. of Rhode Island, Narragansett, RI (United States)

    1995-12-31

    The role of interstitial cadmium and acid volatile sulfide (AVS) in controlling the bioavailability of sediment-associated metal was examined using the chronic saltwater benthic colonization test. Sediments were spiked with cadmium to achieve simultaneously extracted metal (SEM)/AVS molar ratios of 0. 0 (control), 0.1, 0.8 and 3.0 in this 118-day test. Oxidation of AVS in the surficial 2.4 cm within two to four weeks resulted in sulfide profiles similar to those occurring naturally in local sediments. In the nominal 0.1 SEM/AVS treatment, measured SEM was always less than AVS. Interstitial cadmium concentrations (< 3--10 {micro}g/L) were below those likely to cause biological effects. No significant biological effects were detected. In the nominal 0.8 SEM/AVS treatment, measured SEM commonly exceeded AVS in the surficial 2.4 cm of sediment. Interstitial cadmium concentrations (24--157 {micro}g/L) were likely of toxicological significance to sensitive species. Shifts were observed in presence/absence of species, and there were fewer macrobenthic polychaetes (Mediomastus ambiseta, Strebloapio benedicti and Podarke obscura) and unidentified meiofaunal nematodes. In the nominal 3.0 SEM/AVS treatment, concentrations of SEM were always greater than AVS throughout the sediment column. Interstitial cadmium ranged from 28,000 to 174,000 {micro}g/L. In addition to the effects above, these sediments were colonized by fewer macrobenthic species, polychaete species and harpacticoids; had lower densities of diatoms; lacked bivalve molluscs and exhibited other impacts. The observed biological responses were consistent with measured SEM/AVS ratios in surficial sediments and interstitial water cadmium concentrations, further supporting their utility in predicting metals bioavailability.

  3. Identification of volatile organic compounds in human cerumen

    PubMed Central

    Prokop-Prigge, Katharine A.; Thaler, Erica; Wysocki, Charles J.; Preti, George

    2014-01-01

    We report here the initial examination of volatile organic compounds (VOCs) emanating from human earwax (cerumen). Recent studies link a single nucleotide polymorphism (SNP) in the adenosine triphosphate (ATP) binding cassette, sub-family C, member 11 gene (ABCC11) to the production of different types of axillary odorants and cerumen. ABCC11 encodes an ATP-driven efflux pump protein that plays an important function in ceruminous apocrine glands of the auditory canal and the secretion of axillary odor precursors. The type of cerumen and underarm odor produced by East Asians differ markedly from that produced by non-Asians. In this initial report we find that both groups emit many of the same VOCs but differ significantly in the amounts produced. The principal odorants are volatile organic C2-to-C6 acids. The physical appearance of cerumen from the two groups also matches previously reported ethnic differences, viz., cerumen from East Asians appears dry and white while that from non-Asians is typically wet and yellowish-brown. PMID:24572763

  4. Volatile organic compound stripping at clarifier weirs

    SciTech Connect

    Zytner, R.G.; Rahme, Z.G.; Corsi, R.L.; Labocha, M.; Parker, W.

    1999-10-01

    Volatile organic compound (VOC) stripping at clarifier weirs was investigated for both clean water and primary wastewater using a pilot-scale model with a cross-sectional geometry similar to clarifier weirs. Drop height, type of flow regime over the weir, and weir shape were identified as important parameters influencing mass transfer. It was also observed that VOC stripping from free-fall flow could be correlated with Henry's law constant. A model that accounts for liquid- and gas-phase mass transfer was developed to predict VOC stripping from clean water. The relatively low and consistent gas- and liquid-phase mass-transfer coefficients used in the model suggest that a representative value may apply for all weir conditions. Incorporating a transition coefficient between clean water and wastewater made it possible to predict VOC transfer in primary wastewater based on clean water data. Experimental results and modeling efforts described in this paper could serve as a first step in estimating VOC emissions for flows over clarifiers at wastewater treatment plants.

  5. Catalytic destruction of organic volatile nitrogen compounds

    SciTech Connect

    Lester, G.R.; Homeyer, S.T. [Allied Signal Inc., Des Plaines, IL (United States)

    1993-12-31

    A family of catalysts has been identified for purification of industrial gas streams which are contaminated with odorous and/or toxic volatile nitrogen compounds (VNC). Temperature-conversion curves were measured for destruction of a series of organic VNC`s in moist air at 15,000 hr {sup {minus}1} gas hourly space velocity (STP), and the yields of N{sub 2}, N{sub 2}O, and total NO{sub x} (NO + NO{sub 2}) were measured. The VNCs of interest included primary, secondary and tertiary amines, ethylenediamine, ethanolamine, acetonitrile, dimethylfomamide, pyridine, piperidine and aniline. The ease of destruction of these compounds over a monolithic platinum VNC catalyst as reflected in the temperature required or 95% conversion, ranged from n-propylamine (234{degrees}C) to acetonitrile (343{degrees}C). Selectivity to N{sub 2} plus N{sub 2}O at the temperatures of 95% conversion decreased with increasing T-95 from 93% to 46%. Additional studies were done with triethylamine at several space velocities with the VNC catalyst and with some related PT catalysts. The results of these tests suggest that N{sub 2}, N{sub 2}O, and NO{sub x} (NO + NO{sub 2}) are formed by at least three competitive reaction pathways.

  6. Production of volatile organic compounds by mycobacteria.

    PubMed

    McNerney, Ruth; Mallard, Kim; Okolo, Phyllis Ifeoma; Turner, Claire

    2012-03-01

    The need for improved rapid diagnostic tests for tuberculosis disease has prompted interest in the volatile organic compounds (VOCs) emitted by Mycobacterium tuberculosis complex bacteria. We have investigated VOCs emitted by Mycobacterium bovis BCG grown on Lowenstein-Jensen media using selected ion flow tube mass spectrometry and thermal desorption-gas chromatography-mass spectrometry. Compounds observed included dimethyl sulphide, 3-methyl-1-butanol, 2-methyl-1-propanol, butanone, 2-methyl-1-butanol, methyl 2-methylbutanoate, 2-phenylethanol and hydrogen sulphide. Changes in levels of acetaldehyde, methanol and ammonia were also observed. The compounds identified are not unique to M. bovis BCG, and further studies are needed to validate their diagnostic value. Investigations using an ultra-rapid gas chromatograph with a surface acoustic wave sensor (zNose) demonstrated the presence of 2-phenylethanol (PEA) in the headspace of cultures of M. bovis BCG and Mycobacterium smegmatis, when grown on Lowenstein-Jensen supplemented with glycerol. PEA is a reversible inhibitor of DNA synthesis. It is used during selective isolation of gram-positive bacteria and may also be used to inhibit mycobacterial growth. PEA production was observed to be dependent on growth of mycobacteria. Further study is required to elucidate the metabolic pathways involved and assess whether this compound is produced during in vivo growth of mycobacteria. PMID:22224870

  7. Breath measurements as volatile organic compound biomarkers

    SciTech Connect

    Wallace, L.; Buckley, T. [Environmental Protection Agency, Reston, VA (United States); Pellizzari, E. [Research Triangle Institute, Research Triangle Park, NC (United States); Gordon, S. [Battelle Memorial Institute, Columbus, OH (United States)

    1996-10-01

    A brief review of the uses of breath analysis in studies of environmental exposure to volatile organic compounds (VOCs) is provided. The U.S. Environmental Protection Agency`s large-scale Total Exposure Assessment Methodology Studies have measured concentrations of 32 target VOCs in the exhaled breath of about 800 residents of various U.S. cities. Since the previous 12-hr integrated personal air exposures to the same chemicals were also measured, the relation between exposure and body burden is illuminated. Another major use of the breath measurements has been to detect unmeasured pathways of exposure; the major impact of active smoking on exposure to benzene and styrene was detected in this way. Following the earlier field studies, a series of chamber studies have provided estimates of several important physiological parameters. Among these are the fraction, f, of the inhaled chemical that is exhaled under steady-state conditions and the residence times, {tau}{sub i} in several body compartments, which may be associated with the blood (or liver), organs, muscle, and fat. Most of the targeted VOCs appear to have similar residence times of a few minutes, 30 min, several hours, and several days in the respective tissue groups. Knowledge of these parameters can be helpful in estimating body burden from exposure or vice versa and in planning environmental studies, particularly in setting times to monitor breath in studies of the variation with time of body burden. Improvements in breath methods have made it possible to study short-term peak exposure situations such as filling a gas tank or taking a shower in contaminated water. 81 refs., 3 figs., 4 tabs.

  8. Modeling the transport of volatile organics in variably saturated media

    Microsoft Academic Search

    B. E. Sleep; J. F. Sykes

    1989-01-01

    The understanding of the processes of dissolution, volatilization, and gas-liquid partitioning in porous media is very limited. The few models which attempt to characterize the transport of volatile organics such as petroleum products and halogenated hydrocarbon solvents in variably saturated media all assume that mass transfer processes are at equilibrium. In addition, gas phase advection is neglected by assuming that

  9. Microorganisms for producing organic acids

    DOEpatents

    Pfleger, Brian Frederick; Begemann, Matthew Brett

    2014-09-30

    Organic acid-producing microorganisms and methods of using same. The organic acid-producing microorganisms comprise modifications that reduce or ablate AcsA activity or AcsA homolog activity. The modifications increase tolerance of the microorganisms to such organic acids as 3-hydroxypropionic acid, acrylic acid, propionic acid, lactic acid, and others. Further modifications to the microorganisms increase production of such organic acids as 3-hydroxypropionic acid, lactate, and others. Methods of producing such organic acids as 3-hydroxypropionic acid, lactate, and others with the modified microorganisms are provided. Methods of using acsA or homologs thereof as counter-selectable markers are also provided.

  10. Volatile Organic Compound Analysis in Istanbul

    NASA Astrophysics Data System (ADS)

    ?apraz, Ö.; Deniz, A.; Öztürk, A.; Incecik, S.; Toros, H.; Co?kun, M.

    2012-04-01

    Volatile Organic Compound Analysis in Istanbul Ö. Çapraz1, A. Deniz1,3, A. Ozturk2, S. Incecik1, H. Toros1 and, M. Coskun1 (1) Istanbul Technical University, Faculty of Aeronautics and Astronautics, Department of Meteorology, 34469, Maslak, Istanbul, Turkey. (2) Istanbul Technical University, Faculty of Chemical and Metallurgical, Chemical Engineering, 34469, Maslak, Istanbul, Turkey. (3) Marmara Clean Air Center, Ministry of Environment and Urbanization, Ni?anta??, 34365, ?stanbul, Turkey. One of the major problems of megacities is air pollution. Therefore, investigations of air quality are increasing and supported by many institutions in recent years. Air pollution in Istanbul contains many components that originate from a wide range of industrial, heating, motor vehicle, and natural emissions sources. VOC, originating mainly from automobile exhaust, secondhand smoke and building materials, are one of these compounds containing some thousands of chemicals. In spite of the risks to human health, relatively little is known about the levels of VOC in Istanbul. In this study, ambient air quality measurements of 32 VOCs including hydrocarbons, halogenated hydrocarbons and carbonyls were conducted in Ka??thane (Golden Horn) region in Istanbul during the winter season of 2011 in order to develop the necessary scientific framework for the subsequent developments. Ka??thane creek valley is the source part of the Golden Horn and one of the most polluted locations in Istanbul due to its topographical form and pollutant sources in the region. In this valley, horizontal and vertical atmospheric motions are very weak. The target compounds most commonly found were benzene, toluene, xylene and ethyl benzene. Concentrations of total hydrocarbons ranged between 1.0 and 10.0 parts per billion, by volume (ppbv). Ambient air levels of halogenated hydrocarbons appeared to exhibit unique spatial variations and no single factor seemed to explain trends for this group of compounds. N-octane, 3-methylheptane, n-nonane, 2,3,4-trimethylpentane and n-hexane parameters ranged between 3 ppbv and maximum value of 10 ppbv. The other VOC parameters are measured below 3 ppbv value. At participating urban locations for the year of data considered, levels of carbonyls were higher than the level of the other organic compound groups, suggesting that emissions from motor vehicles and photochemical reactions strongly in?uence ambient air concentrations of carbonyls. Of the most prevalent carbonyls, formaldehyde and acetaldehyde were the dominant compounds, ranging from 1.5-7.4 ppbv for formaldehyde, to 0.8-2.7 ppbv for acetaldehyde. Keywords: Air quality, Volatile Organic Compounds (VOC), industry, meteorology, urban, Ka??thane, ?stanbul. Acknowledgment: This work was part of the TUJJB-TUMEHAP-01-10 and Turkish Scientific and Technical Research Council Project No: 109Y132.

  11. Recovery of organic acids

    DOEpatents

    Verser, Dan W. (Golden, CO); Eggeman, Timothy J. (Lakewood, CO)

    2009-10-13

    A method is disclosed for the recovery of an organic acid from a dilute salt solution in which the cation of the salt forms an insoluble carbonate salt. A tertiary amine and CO.sub.2 are introduced to the solution to form the insoluble carbonate salt and a complex between the acid and an amine. A water immiscible solvent, such as an alcohol, is added to extract the acid/amine complex from the dilute salt solution to a reaction phase. The reaction phase is continuously dried and a product between the acid and the solvent, such as an ester, is formed.

  12. Recovery of organic acids

    SciTech Connect

    Verser, Dan W. (Menlo Park, CA); Eggeman, Timothy J. (Lakewood, CO)

    2011-11-01

    A method is disclosed for the recovery of an organic acid from a dilute salt solution in which the cation of the salt forms an insoluble carbonate salt. A tertiary amine and CO.sub.2 are introduced to the solution to form the insoluble carbonate salt and a complex between the acid and an amine. A water immiscible solvent, such as an alcohol, is added to extract the acid/amine complex from the dilute salt solution to a reaction phase. The reaction phase is continuously dried and a product between the acid and the solvent, such as an ester, is formed.

  13. MODIFICATION OF METAL PARTITIONING BY SUPPLEMENTING ACID VOLATILE SULFIDE IN FRESHWATER SEDIMENTS

    EPA Science Inventory

    Acid volatile sulfide is a component of sediments which complexes some cationic metals and thereby influences the toxicity of these metals to benthic organisms. EPA has proposed AVS as a key normalization phase for the development of sediment quality criteria for metals. Experime...

  14. Volatile fatty acids as indicators of process imbalance in anaerobic digestors

    Microsoft Academic Search

    B. K. Ahring; M. Sandberg; I. Angelidaki

    1995-01-01

    In continuously stirred tank reactor experiments, with manure as substrate at thermophilic temperatures, the use of volatile fatty acids (VFA) as process indicators was investigated. Changes in VFA level were shown to be a good parameter for indicating process instability. The VFA were evaluated according to their relative changes caused by changes in hydraulic loading, organic loading or temperature. Butyrate

  15. ABSORPTION DES ACIDES GRAS VOLATILS DANS L'OMASUM DE LA VACHE

    E-print Network

    Boyer, Edmond

    ABSORPTION DES ACIDES GRAS VOLATILS DANS L'OMASUM DE LA VACHE C. DARDILLAT Station de rôle du feuillet et ses capacités d'absorption sont très mal connus car il est difficile d'accé- der à cet organe sans perturber son fonctionnement. Nous avons fixé par effet ventouse une chambre d'absorption

  16. 40 CFR 60.432 - Standard for volatile organic compounds.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for the Graphic Arts Industry: Publication Rotogravure Printing § 60.432 Standard for volatile organic compounds. During the period of the performance test required to be...

  17. 40 CFR 60.432 - Standard for volatile organic compounds.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for the Graphic Arts Industry: Publication Rotogravure Printing § 60.432 Standard for volatile organic compounds. During the period of the performance test required to be...

  18. ODOR AND IRRITATION EFFECTS OF A VOLATILE ORGANIC COMPOUND MIXTURE

    EPA Science Inventory

    Human exposure to volatile organic compounds elicits a variety ofsymptoms, many of which are thought to be mediated by the olfactoryand trigeminal systems. his report describes evidence indicatingthat perceived odor intensity diminishes during prolonged exposure,whearas irritatin...

  19. COMPACT, CONTINUOUS MONITORING FOR VOLATILE ORGANIC COMPOUNDS - PHASE I

    EPA Science Inventory

    Improved methods for onsite measurement of multiple volatile organic compounds are needed for process control, monitoring, and remediation. This Phase I SBIR project sets forth an optical measurement method that meets these needs. The proposed approach provides an instantaneous m...

  20. 40 CFR 60.392 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Automobile and Light Duty Truck Surface Coating Operations § 60.392 Standards for volatile organic compounds. On and...

  1. 40 CFR 60.432 - Standard for volatile organic compounds.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for the Graphic Arts Industry: Publication Rotogravure Printing § 60.432 Standard for volatile organic compounds. During the...

  2. Volatile organic compounds from a Tuber melanosporum fermentation system.

    PubMed

    Li, Yuan-Yuan; Wang, Guan; Li, Hong-Mei; Zhong, Jian-Jiang; Tang, Ya-Jie

    2012-12-15

    A total of 59 volatile organic compounds (VOCs) were identified from Tuber melanosporum fermentation: 53 from its fermented mycelia and 32 from the fermentation broth. Alcohol-derived compounds were predominant in both the fermentation mycelia and the broth, although long chain fatty acids and isoprenoids were, for the first time, also found in the mycelia. The intense wine bouquet properties of the broth arose from several specific flavor substances, including sulfur compounds, pyrazines, furans and jasmones. Comparing the VOCs identified in this work with those previously reported, our results are more similar to the composition of the Tuber fruiting-body than previous Tuber fermentations. The composition and accumulation of flavor volatiles (e.g., pyrazines, sulfur compounds, and esters) and major constituents (e.g., 3-methyl-1-butanol and 2-phenylethanol) in this fermentation were significantly influenced by the sucrose concentration in the medium. The obtained information could therefore be useful in applications to convert the flavors of truffle mycelia similar to those of the fruiting-body by optimising the fermentation process. PMID:22980851

  3. Enantiomer distribution of major chiral volatile organic compounds in selected types of herbal honeys.

    PubMed

    Pažitná, Alexandra; Džúrová, Jana; Spánik, Ivan

    2014-10-01

    In this article, volatile organic compounds in 14 honey samples (rosemary, eucalyptus, orange, thyme, sage, and lavender) were identified. Volatile organic compounds were extracted using a solid phase microextraction method followed by gas chromatography connected with mass spectrometry analysis. The studied honey samples were compared based on their volatile organic compounds composition. In total, more than 180 compounds were detected in the studied samples. The detected compounds belong to various chemical classes such as terpenes, alcohols, acids, aldehydes, ketones, esters, norisoprenoids, benzene and furane derivatives, and organic compounds containing sulfur and nitrogen heteroatom. Ten chiral compounds (linalool, trans-linalool oxide, cis-linalool oxide, 4-terpineol, ?-terpineol, hotrienol, and four stereoisomers of lilac aldehydes) were selected for further chiral separation. PMID:25099214

  4. Determination of total carbon and total organic carbon from volatile air pollutants. Part II

    Microsoft Academic Search

    Edmund Kozlowski; Jacek Namie?nik

    1978-01-01

    Summary The possibility of specific removal of carbon monoxide from a stream of air in the presence of vapours of volatile organic compounds was investigated. Weighed samples of oxalic acid were pyrolyzed to obtain standard mixtures of CO with air. Carbon monoxide present in the stream of air (at the flow rate of 700 cm3\\/ min) is quantitatively oxidized to

  5. FIELD SCREENING FOR HALOGENATED VOLATILE ORGANIC COMPOUNDS

    SciTech Connect

    John F. Schabron; Joseph F. Rovani, Jr.; Theresa M. Bomstad

    2003-07-01

    Western Research Institute (WRI) is continuing work toward the development of new screening methodology and a test kit to measure halogenated volatile organic compounds (VOCs) in the field. Heated diode and corona discharge sensors are commonly used to detect leaks of refrigerants from air conditioners, freezers, and refrigerators. They are both selective to the presence of halogens. In prior work, the devices were tested for response to carbon tetrachloride, heptane, toluene, and water vapors. In the current work, sensor response was evaluated with sixteen halogenated VOCs relative to carbon tetrachloride. The results show that the response of the various chlorinated VOCs is within an order of magnitude of the response to carbon tetrachloride for each of the sensors. Thus, for field screening a single response factor can be used. Both types of leak detectors are being further modified to provide an on-board LCD signal readout, which is related to VOC concentration. The units will be fully portable and will operate with 115-V line or battery power. Signal background, noise level, and response data on the Bacharach heated diode detector and the TIF corona discharge detector show that when the response curves are plotted against the log of concentration, the plot is linear to the upper limit for the particular unit, with some curvature at lower levels. When response is plotted directly against concentration, the response is linear at the low end and is curved at the high end. The dynamic ranges for carbon tetrachloride of the two devices from the lower detection limit (S/N=2) to signal saturation are 4-850 vapor parts per million (vppm) for the corona discharge unit and 0.01-70 vppm for the heated diode unit. Additional circuit modifications are being made to lower the detection limit and increase the dynamic response range of the corona discharge unit. The results indicate that both devices show potential utility for future analytical method development work toward the goal of developing a portable test kit for screening halogenated VOCs in the field.

  6. 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.

  7. Online measurements of the emissions of intermediate-volatility and semi-volatile organic compounds from aircraft

    E-print Network

    Herndon, S. C.

    A detailed understanding of the climate and air quality impacts of aviation requires measurements of the emissions of intermediate-volatility and semi-volatile organic compounds (I/SVOCs) from aircraft. Currently both the ...

  8. Gas chromatography of volatile organic compounds

    NASA Technical Reports Server (NTRS)

    Zlatkis, A.

    1973-01-01

    System has been used for problems such as analysis of volatile metabolities in human blood and urine, analysis of air pollutants, and in tobacco smoke chemistry. Since adsorbent is reusable after porper reconditioning, method is both convenient and economical. System could be used for large scale on-site sampling programs in which sample is shipped to central location for analysis.

  9. Heterogeneous reactions of volatile organic compounds in the atmosphere

    NASA Astrophysics Data System (ADS)

    Shen, Xiaoli; Zhao, Yue; Chen, Zhongming; Huang, Dao

    2013-04-01

    Volatile organic compounds (VOCs) are of central importance in the atmosphere because of their close relation to air quality and climate change. As a significant sink for VOCs, the fate of VOCs via heterogeneous reactions may explain the big gap between field and model studies. These reactions play as yet unclear but potentially crucial role in atmospheric processes. In order to better evaluate this reaction pathway, we present the first specific review for the progress of heterogeneous reaction studies on VOCs, including carbonyl compounds, organic acids, alcohols, and so on. Our review focuses on the processes for heterogeneous reactions of VOCs under varying experimental conditions, as well as their implications for trace gas and HOx budget, secondary organic aerosol (SOA) formation, physicochemical properties of aerosols, and human health. Finally, we propose the future direction for laboratory studies of heterogeneous chemistry of VOCs that should be carried out under more atmospherically relevant conditions, with a special emphasis on the effects of relative humidity and illumination, the multicomponent reaction systems, and reactivity of aged and authentic particles. In particular, more reliable uptake coefficients, based on the abundant elaborate laboratory studies, appropriate calibration, and logical choice criterion, are urgently required in atmospheric models.

  10. Emission, oxidation, and secondary organic aerosol formation of volatile organic compounds as observed at Chebogue Point,

    E-print Network

    Silver, Whendee

    organic compounds (VOC) are oxidized in the troposphere. There are three possible final stages or out] Oxidation products of primary VOC emissions tend to become less volatile and more soluble becauseEmission, oxidation, and secondary organic aerosol formation of volatile organic compounds

  11. Concentration stability of four volatile organic compounds in soil subsamples

    SciTech Connect

    Hewitt, A.D.

    1994-04-01

    This study assesses the short-term (14- to 20-day) concentration stability of benzene, toluene, trans-1,2-dichloroethylene and trichloroethylene in soil matrices, in the absence of volatilization losses. Previously, holding time studies failed to eliminate volatilization as a variable, making them difficult to interpret. Here, vapor-fortified soil subsamples, sealed in glass ampoules for 16 days, experienced appreciable reductions in benzene, presumably attributable only to biodegradation. Treated soil subsamples, on the other hand, prepared without vapor losses for either aqueous extraction headspace or purge-and-trap analyses, showed appreciable reductions in toluene and lost all the benzene over a 14-day holding period at 4 deg C. These findings suggest that chemical preservatives are necessary to maintain volatile organic compound concentrations in soil when more than a couple of days pass between collection and analysis. Biodegradation, Soil samples, Holding time, Volatile-organic compounds.

  12. Analysis of volatile organic compounds from illicit cocaine samples

    SciTech Connect

    Robins, W.H.; Wright, B.W.

    1994-07-01

    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 that 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.

  13. Biological aspects of constructing volatile organic compound emission inventories

    Microsoft Academic Search

    Ray Fall; Mt Lerdau; Td Sharkey

    1995-01-01

    The: emission of volatile organic compounds (VOCs) from vegetation is subject to numerous biological controls. Past inventories have relied heavily on empirical models which are limited in their ability to simulate the response of organisms to short- and long-term changes in their growth environment. In this review we consider the principal biochemical, physiological and ecological controls over VOC emission with

  14. Emission of volatile organic compounds from coal combustion

    Microsoft Academic Search

    H. K Chagger; J. M Jones; M Pourkashanian; A Williams; A Owen; G Fynes

    1999-01-01

    The combustion of coal leads to the formation of small but significant amounts of volatile organic compounds (VOCs), toxic organic micropollutants as polynuclear aromatic hydrocarbons (PAHs), as well as CH4. The measurements of such trace emissions is difficult and expensive, consequently it is useful to examine these from a kinetic modelling and thermodynamic point of view in order to make

  15. Oxidation of Volatile Organic Compounds in Aqueous Solution and

    E-print Network

    Winfree, Erik

    i Oxidation of Volatile Organic Compounds in Aqueous Solution and at the Air-water Interface ABSTRACT Isoprene (ISO), the most abundant non-methane VOC, is the major contributor to secondary organic. Current mechanisms, which are based on the oxidation of ISO in the gas-phase, underestimate SOA yields

  16. Degradation of volatile fatty acids in highly efficient anaerobic digestion

    Microsoft Academic Search

    Qunhui Wang; Masaaki Kuninobu; Hiroaki I Ogawa; Yasuhiko Kato

    1999-01-01

    To improve the efficiency of anaerobic digestion, we examined the effects of C2–C6 volatile fatty acids (VFAs) on methane fermentation, as well as the behavior of VFAs in anaerobic digestion. The VFA concentrations and methane production in anaerobic digestion were increased by pretreatment of waste activated sludge (WAS), such as ultrasonic disintegration, thermal and freezing treatments. The major intermediate products

  17. Biodegradation of volatile organic compounds by five fungal species.

    PubMed

    Qi, B; Moe, W M; Kinney, K A

    2002-04-01

    Five fungal species, Cladosporium resinae (ATCC 34066), Cladosporium sphaerospermum (ATCC 200384), Exophiala lecanii-corni (CBS 102400), Mucor rouxii (ATCC 44260), and Phanerochaete chrysosporium (ATCC 24725), were tested for their ability to degrade nine compounds commonly found in industrial off-gas emissions. Fungal cultures inoculated on ceramic support media were provided with volatile organic compounds (VOCs) via the vapor phase as their sole carbon and energy sources. Compounds tested included aromatic hydrocarbons (benzene, ethylbenzene, toluene, and styrene), ketones (methyl ethyl ketone, methyl isobutyl ketone, and methyl propyl ketone), and organic acids ( n-butyl acetate, ethyl 3-ethoxypropionate). Experiments were conducted using three pH values ranging from 3.5 to 6.5. Fungal ability to degrade each VOC was determined by observing the presence or absence of visible growth on the ceramic support medium during a 30-day test period. Results indicate that E. lecanii-corni and C. sphaerospermum can readily utilize each of the nine VOCs as a sole carbon and energy source. P. chrysosporium was able to degrade all VOCs tested except for styrene under the conditions imposed. C. resinae was able to degrade both organic acids, all of the ketones, and some of the aromatic compounds (ethylbenzene and toluene); however, it was not able to grow utilizing benzene or styrene under the conditions tested. With the VOCs tested, M. rouxiiproduced visible growth only when supplied with n-butyl acetate or ethyl 3-ethoxypropionate. Maximum growth for most fungi was observed at a pH of approximately 5.0. The experimental protocol utilized in these studies is a useful tool for assessing the ability of different fungal species to degrade gas-phase VOCs under conditions expected in a biofilter application. PMID:11956756

  18. Volatile organic compounds at swine facilities: a critical review.

    PubMed

    Ni, Ji-Qin; Robarge, Wayne P; Xiao, Changhe; Heber, Albert J

    2012-10-01

    Volatile organic compounds (VOCs) are regulated aerial pollutants that have environmental and health concerns. Swine operations produce and emit a complex mixture of VOCs with a wide range of molecular weights and a variety of physicochemical properties. Significant progress has been made in this area since the first experiment on VOCs at a swine facility in the early 1960s. A total of 47 research institutions in 15 North American, European, and Asian countries contributed to an increasing number of scientific publications. Nearly half of the research papers were published by U.S. institutions. Investigated major VOC sources included air inside swine barns, in headspaces of manure storages and composts, in open atmosphere above swine wastewater, and surrounding swine farms. They also included liquid swine manure and wastewater, and dusts inside and outside swine barns. Most of the sample analyses have been focusing on identification of VOC compounds and their relationship with odors. More than 500 VOCs have been identified. About 60% and 10% of the studies contributed to the quantification of VOC concentrations and emissions, respectively. The largest numbers of VOC compounds with reported concentrations in a single experimental study were 82 in air, 36 in manure, and 34 in dust samples. The relatively abundant VOC compounds that were quantified in at least two independent studies included acetic acid, butanoic acid (butyric acid), dimethyl disulfide, dimethyl sulfide, iso-valeric, p-cresol, propionic acid, skatole, trimethyl amine, and valeric acid in air. They included acetic acid, p-cresol, iso-butyric acid, butyric acid, indole, phenol, propionic acid, iso-valeric acid, and skatole in manure. In dust samples, they were acetic acid, propionic acid, butyric acid, valeric acid, p-cresol, hexanal, and decanal. Swine facility VOCs were preferentially bound to smaller-size dusts. Identification and quantification of VOCs were restricted by using instruments based on gas Chromatography (GC) and liquid chromatography (LC) with different detectors most of which require time-consuming procedures to obtain results. Various methodologies and technologies in sampling, sample preparation, and sample analysis have been used. Only four publications reported using GC based analyzers and PTR-MS (proton-transfer-reaction mass spectrometry) that allowed continuous VOC measurement. Because of this, the majority of experimental studies were only performed on limited numbers of air, manure, or dust samples. Many aerial VOCs had concentrations that were too low to be identified by the GC peaks. Although VOCs emitted from swine facilities have environmental concerns, only a few studies investigated VOC emission rates, which ranged from 3.0 to 176.5mgd(-1)kg(-1) pig at swine finishing barns and from 2.3 to 45.2gd(-1)m(-2) at manure storages. Similar to the other pollutants, spatial and temporal variations of aerial VOC concentrations and emissions existed and were significantly affected by manure management systems, barn structural designs, and ventilation rates. Scientific research in this area has been mainly driven by odor nuisance, instead of environment or health concerns. Compared with other aerial pollutants in animal agriculture, the current scientific knowledge about VOCs at swine facilities is still very limited and far from sufficient to develop reliable emission factors. PMID:22682363

  19. Role of volatile acids in development of the cecal microflora in broilers chickens during growth

    Microsoft Academic Search

    Wielen van der P. W. J. J; STEEF BIESTERVELD; S. Notermans; H. Hofstra; B. A. P. Urlings; F. van Knapen

    2000-01-01

    It is known that volatile fatty acids can inhibit growth of species of the family Enterobacteriaceae in vitro. However, whether these volatile fatty acids affect bacterial populations in the ceca of chickens is unknown. Therefore, a study was conducted to investigate if changes in volatile fatty acids in ceca of broiler chickens during growth affect bacterial populations. Results showed that

  20. Quantifying commuter exposures to volatile organic compounds

    NASA Astrophysics Data System (ADS)

    Kayne, Ashleigh

    Motor-vehicles can be a predominant source of air pollution in cities. Traffic-related air pollution is often unavoidable for people who live in populous areas. Commuters may have high exposures to traffic-related air pollution as they are close to vehicle tailpipes. Volatile organic compounds (VOCs) are one class of air pollutants of concern because exposure to VOCs carries risk for adverse health effects. Specific VOCs of interest for this work include benzene, toluene, ethylbenzene, and xylenes (BTEX), which are often found in gasoline and combustion products. Although methods exist to measure time-integrated personal exposures to BTEX, there are few practical methods to measure a commuter's time-resolved BTEX exposure which could identify peak exposures that could be concealed with a time-integrated measurement. This study evaluated the ability of a photoionization detector (PID) to measure commuters' exposure to BTEX using Tenax TA samples as a reference and quantified the difference in BTEX exposure between cyclists and drivers with windows open and closed. To determine the suitability of two measurement methods (PID and Tenax TA) for use in this study, the precision, linearity, and limits of detection (LODs) for both the PID and Tenax TA measurement methods were determined in the laboratory with standard BTEX calibration gases. Volunteers commuted from their homes to their work places by cycling or driving while wearing a personal exposure backpack containing a collocated PID and Tenax TA sampler. Volunteers completed a survey and indicated if the windows in their vehicle were open or closed. Comparing pairs of exposure data from the Tenax TA and PID sampling methods determined the suitability of the PID to measure the BTEX exposures of commuters. The difference between BTEX exposures of cyclists and drivers with windows open and closed in Fort Collins was determined. Both the PID and Tenax TA measurement methods were precise and linear when evaluated in the laboratory using standard BTEX gases. The LODs for the Tenax TA sampling tubes (determined with a sample volume of 1,000 standard cubic centimeters which is close to the approximate commuter sample volumes collected) were orders of magnitude lower (0.04 to 0.7 parts per billion (ppb) for individual compounds of BTEX) compared to the PIDs' LODs (9.3 to 15 ppb of a BTEX mixture), which makes the Tenax TA sampling method more suitable to measure BTEX concentrations in the sub-parts per billion (ppb) range. PID and Tenax TA data for commuter exposures were inversely related. The concentrations of VOCs measured by the PID were substantially higher than BTEX concentrations measured by collocated Tenax TA samplers. The inverse trend and the large difference in magnitude between PID responses and Tenax TA BTEX measurements indicates the two methods may have been measuring different air pollutants that are negatively correlated. Drivers in Fort Collins, Colorado with closed windows experienced greater time-weighted average BTEX exposures than cyclists (p: 0.04). Commuter BTEX exposures measured in Fort Collins were lower than commuter exposures measured in prior studies that occurred in larger cities (Boston and Copenhagen). Although route and intake may affect a commuter's BTEX dose, these variables are outside of the scope of this study. Within the limitations of this study (including: small sample size, small representative area of Fort Collins, and respiration rates not taken into account), it appears health risks associated with traffic-induced BTEX exposures may be reduced by commuting via cycling instead of driving with windows closed and living in a less populous area that has less vehicle traffic. Although the PID did not reliably measure low-level commuter BTEX exposures, the Tenax TA sampling method did. The PID measured BTEX concentrations reliably in a controlled environment, at high concentrations (300-800 ppb), and in the absence of other air pollutants. In environments where there could be multiple chemicals present that may produce a PID signal (such a

  1. Acid Catalysis in Modern Organic

    E-print Network

    Snyder, Scott A.

    Acid Catalysis in Modern Organic Synthesis "Acid is one of the oldest, but the most important follows their earlier book "Lewis Acids in Organic Synthesis (2000)", and covers the new developments of university studies, in which an evil-smelling carbox- ylic acid and an alcohol were converted into a fragrant

  2. Fungal wood decay in the presence of fly ash as indicated by gravimetrics and by extractability of low molecular weight volatile organic acids

    Microsoft Academic Search

    Barbara Piškur; Janja Zule; Mitja Piškur; Dušan Jurc; Franc Pohleven

    2009-01-01

    A mycoremediation system of wood substrate and fungal inoculum was established on an organically poor fly ash deposit at the Šoštanj Thermal Power Plant, Slovenia. A mini-block method with beech wood samples was used to select a suitable fungal isolate for inoculation into the mycoremediation system. Pleurotus ostreatus ZIM 76 proved to be the most appropriate for further tests. Compared

  3. Speciation of volatile organic compounds from poultry production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The air consent agreement between EPA and large animal feeding operations (AFO) is designed to determine at what level compounds are being emitted from these facilities. However, the methodology used for quantifying total non-methane hydrocarbons and speciation of volatile organic compounds (VOC) n...

  4. AERATION TO REMOVE VOLATILE ORGANIC COMPOUNDS FROM GROUND WATER

    EPA Science Inventory

    The interim report presents general information on the use of aeration to remove volatile organic compounds from drinking water for public health reasons. The report illustrates the types of aerators, shows where they are being used, presents a means of estimating aeration perfor...

  5. Volatile organic compound emissions from dairy facilities in central California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Emissions of volatile organic compounds (VOCs) from dairy facilities are thought to be an important contributor to high ozone levels in central California, but emissions inventories from these sources contain significant uncertainties. In this work, VOC emissions were measured at two central Califor...

  6. CHARACTERIZATION OF VOLATILE ORGANIC COMPOUNDS IN AIRBORNE DUST

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three methods of extracting volatile organic compounds (VOC's) adsorbed on the airborne dust in a swine finishing building were investigated. Airborne dust was collected in pre-baked glass fiber filters (GFF's) and the compounds were extracted by solvent extraction using dichloromethane, solid phas...

  7. 40 CFR 60.582 - Standard for volatile organic compounds.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Flexible Vinyl and Urethane Coating and Printing § 60.582 Standard for volatile organic...this subpart shall either: (1) Use inks with a weighted average VOC content less than 1.0 kilogram VOC per kilogram ink solids at each affected facility,...

  8. MICROBIAL VOLATILE ORGANIC COMPOUND EMISSION RATES AND EXPOSURE MODEL

    EPA Science Inventory

    This paper presents the results from a study that examined microbial volatile organic compound (MVOC) emissions from six fungi and one bacterial species (Streptomyces spp.) commonly found in indoor environments. Data are presented on peak emission rates from inoculated agar plate...

  9. Photocatalytic Oxidation of Volatile Organic Compounds Using Fluorescent Visible Light

    Microsoft Academic Search

    Yannick Chapuis; Danilo Klvana; Christophe Guy; Jitka Kirchnerova

    2002-01-01

    Photocatalytic oxidation (PCO) of volatile organic compounds (VOCs) is a highly attractive alternative technology for purification and deodorization of indoor air. The main objectives of this study were to demonstrate that a common fluorescent visible light (FVL) lamp can be used to effectively remove by PCO low concentrations of VOCs from slightly contaminated air and to provide some fundamental and

  10. Qualitative analysis of volatile organic compounds on biochar

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Qualitative identification of sorbed volatile organic compounds (VOCs) on biochar was conducted by headspace thermal desorption coupled to capillary gas chromatographic-mass spectrometry. VOCs may have a mechanistic role influencing plant and microbial responses to biochar amendments, since VOCs ca...

  11. REMOVAL OF VOLATILE ORGANIC CONTAMINANTS FROM GROUND WATER

    EPA Science Inventory

    Because ground water is a source of potable water for millions of people, an economical means of removing volatile organic contaminants is essential. Laboratory, pilot-scale and full-scale studies are being carried out in the United States of America to determine the effect of va...

  12. A global model of natural volatile organic compound emissions

    Microsoft Academic Search

    Alex Guenther; C. Nicholas Hewitt; David Erickson; Ray Fall; Chris Geron; Tom Graedel; Peter Harley; Lee Klinger; Manuel Lerdau; W. A. McKay; Tom Pierce; Bob Scholes; Rainer Steinbrecher; Raja Tallamraju; John Taylor; Pat Zimmerman

    1995-01-01

    Numerical assessments of global air quality and potential changes in atmospheric chemical constituents require estimates of the surface fluxes of a variety of trace gas species. We have developed a global model to estimate emissions of volatile organic compounds from natural sources (NVOC). Methane is not considered here and has been reviewed in detail elsewhere. The model has a highly

  13. Volatile organic compound (VOC) emissions from soil and litter samples

    Microsoft Academic Search

    Jonathan W. Leff; Noah Fierer

    2008-01-01

    The production of nonmethane volatile organic compounds (VOCs) by soil microbes is likely to have an important influence on soil ecology and terrestrial biogeochemistry. However, soil VOC production has received relatively little attention, and we do not know how the emissions of microbially-produced VOCs vary across soil and litter types. We collected 40 root-free soil and litter samples from a

  14. Influence of volatile organic compounds on Fusarium graminearum mycotoxin production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Volatile organic compounds (VOCs) are involved in a diverse range of ecological interactions. Due to their low molecular weight, lipophilic nature, and high vapor pressure at ambient temperatures, they can serve as airborne signaling molecules that are capable of mediating inter and intraspecies com...

  15. 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 ...

  16. LEAVES AS INDICATORS OF EXPOSURE TO AIRBORNE VOLATILE ORGANIC COMPOUNDS

    EPA Science Inventory

    The concentration of volatile organic compounds (VOCs) in leaves is primarily a product of airborne exposures and dependent upon bioconcentration factors and release rates. The bioconcentration factors for VOCs in grass are found to be related to their partitioning between octan...

  17. Emissions of volatile organic compounds from vegetation and the implications for atmospheric chemistry

    SciTech Connect

    Fehsenfeld, F.; Trainer, M. (National Oceanic and Atmospheric Administration, Boulder, CO (United States) Univ. of Colorado, Boulder (United States)); Calvert, J.; Guenther, A.B.; Zimmerman, P. (National Center for Atmospheric Research, Boulder, CO (United States)); Fall, R. (Univ. of Colorado, Boulder (United States)); Goldan, P.; Liu, S. (National Oceanic and Atmospheric Administration, Boulder, CO (United States)); Hewitt, C.N. (Lancaster Univ. (United Kingdom)); Lamb, B.; Westberg, H. (Washington State Univ., Pullman (United States))

    1992-12-01

    Vegetation provides a major source of reactive carbon entering the atmosphere. These compounds play an important role in (1) shaping global tropospheric chemistry, (2) regional photochemical oxidant formation, (3) balancing the global carbon cycle, and (4) production of organic acids which contribute to acidic deposition in rural areas. Present estimates place the total annual global emission of these compounds between approximately 500 and 825 Tg yr[sup -1]. The volatile olefinic compounds, such as isoprene and the monoterpenes, are thought to constitute the bulk of these emissions. However, it is becoming increasingly clear that a variety of partially oxidized hydrocarbons, principally alcohols, are also emitted. The available information concerning the terrestrial vegetation as sources of volatile organic compounds is reviewed. The biochemical processes associated with these emissions of the compounds and the atmospheric chemistry of the emitted compounds are discussed. 197 refs., 25 figs., 7 tabs.

  18. Emissions of volatile organic compounds from vegetation and the implications for atmospheric chemistry

    NASA Astrophysics Data System (ADS)

    Fehsenfeld, Fred; Calvert, Jack; Fall, Ray; Goldan, Paul; Guenther, Alex B.; Hewitt, C. Nicholas; Lamb, Brian; Liu, Shaw; Trainer, Michael; Westberg, Hal; Zimmerman, Pat

    1992-12-01

    Vegetation provides a major source of reactive carbon entering the atmosphere. These compounds play an important role in (1) shaping global tropospheric chemistry, (2) regional photochemical oxidant formation, (3) balancing the global carbon cycle, and (4) production of organic acids which contribute to acidic deposition in rural areas. Present estimates place the total annual global emission of these compounds between approximately 500 and 825 Tg yr-1. The volatile olefinic compounds, such as isoprene and the monoterpenes, are thought to constitute the bulk of these emissions. However, it is becoming increasingly clear that a variety of partially oxidized hydrocarbons, principally alcohols, are also emitted. The available information concerning the terrestrial vegetation as sources of volatile organic compounds is reviewed. The biochemical processes associated with these emissions of the compounds and the atmospheric chemistry of the emitted compounds are discussed.

  19. History of Martian volatiles - Implications for organic synthesis.

    NASA Technical Reports Server (NTRS)

    Fanale, F. P.

    1971-01-01

    A theoretical reconstruction of the history of Martian volatiles indicates that Mars probably possessed a substantial reducing atmosphere at the outset of its history, and that its present tenuous and more oxidized atmosphere is the result of extensive chemical evolution. As a consequence, it is probable that Martian atmospheric chemical conditions, now hostile with respect to abiotic organic synthesis in the gas phase, were initially favorable. Evidence indicating the chronology and degradational history of Martian surface features, surface mineralogy, bulk volatile content, internal mass distribution, and thermal history suggests that Mars catastrophically developed a substantial reducing atmosphere as the result of rapid accretion.

  20. 77 FR 52630 - Approval and Promulgation of Air Quality Implementation Plans; Indiana; Volatile Organic...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-30

    ...Implementation Plans; Indiana; Volatile Organic Compounds; Architectural and Industrial Maintenance Coatings AGENCY: Environmental...emissions limits on the amount of volatile organic compounds in architectural and industrial maintenance coatings that are sold,...

  1. LOCATING VOLATILE ORGANIC PLUMES ENTERING WATER BODIES USING PASSIVE VAPOR DIFFUSION SAMPLERS

    EPA Science Inventory

    Many water bodies in New England are impacted by volatile organic contaminated groundwater intrusions. To determine the health and ecological impacts of these intrusions, it is important to locate fracture zones that transport groundwater contaminated with volatile organic compou...

  2. Can volatile organic compounds be markers of sea salt?

    PubMed

    Silva, Isabel; Coimbra, Manuel A; Barros, António S; Marriott, Philip J; Rocha, Sílvia M

    2015-02-15

    Sea salt is a handmade food product that is obtained by evaporation of seawater in saltpans. During the crystallisation process, organic compounds from surroundings can be incorporated into sea salt crystals. The aim of this study is to search for potential volatile markers of sea salt. Thus, sea salts from seven north-east Atlantic Ocean locations (France, Portugal, Continental Spain, Canary Islands, and Cape Verde) were analysed by headspace solid-phase microextraction combined with comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry. A total of 165 compounds were detected, ranging from 32 to 71 compounds per salt. The volatile composition revealed the variability and individuality of each salt, and a set of ten compounds were detected in all samples. From these, seven are carotenoid-derived compounds that can be associated with the typical natural surroundings of ocean hypersaline environment. These ten compounds are proposed as potential volatile markers of sea salt. PMID:25236204

  3. A laboratory formulated sediment incorporating synthetic acid volatile sulfide

    SciTech Connect

    Gonzalez, A.M. [Oak Ridge National Lab., TN (United States)

    1995-12-31

    The usefulness of laboratory formulated sediment (LFS) for sediment research applications might be expanded if sediment characteristics other than particle size distribution, organic carbon and pH could be artificially manipulated. This report describes the development of a LFS containing synthetic acid volatile sulfide (AVS). Several formulations were evaluated with respect to their toxicological effects on Hyalella azteca, and their chemical stability and oxidation dynamics in the H. azteca toxicity test system. Optimal amphipod survival was obtained in prepared LFS formulations where the molar cation-to-sulfide ratio was near unity. The synthetic AVS at the surface of the test system oxidized quickly, but was fairly stable for up to 28 days when isolated from air or oxygenated water. AVS analysis of core slices show a clear, dissolved oxygen-diffusion limited oxidation profile. A selected synthetic AVS formulation, as determined by (maximum) H. azteca survival, was evaluated with respect to complexation of copper and nickel, and the corresponding reduction in metal bioavailability. The toxicity of whole sediment and pore water from metal-spiked LFS containing synthetic AVS was evaluated by the 10-d H. azteca toxicity test and the Microtox{reg_sign} bioassay, respectively. As expected, test responses to amended LFS with metal-to-AVS molar ratios less than one were not significantly different than the unspiked, amended LFS. In contrast, amended LFS with metal-to AVS molar ratios greater than one had significant effects on the response of the two test species. Complexation of the metals was confirmed by sediment and pore water chemical analyses. This formulation may provide consistent and controlled substrates with which to investigate metal/sediment chemistry and toxicity, and to develop sediment quality criteria for metals.

  4. Model studies of volatile diesel exhaust particle formation: organic vapours involved in nucleation and growth?

    NASA Astrophysics Data System (ADS)

    Pirjola, L.; Karl, M.; Rönkkö, T.; Arnold, F.

    2015-02-01

    High concentration of volatile nucleation mode particles (NUP) formed in the atmosphere during exhaust cools and dilutes have hazardous health effects and impair visibility in urban areas. Nucleation mechanisms in diesel exhaust are only poorly understood. We performed model studies using two sectional aerosol dynamics process models AEROFOR and MAFOR on the formation of particles in the exhaust of a diesel engine, equipped with an oxidative after-treatment system and running with low fuel sulphur content (FSC), under laboratory sampling conditions where the dilution system mimics real-world conditions. Different nucleation mechanisms were tested; based on the measured gaseous sulphuric acid (GSA) and non-volatile core and soot particle number concentrations of the raw exhaust, the model simulations showed that the best agreement between model predictions and measurements in terms of particle number size distribution was obtained by barrierless heteromolecular homogeneous nucleation between GSA and semi-volatile organic vapour (for example adipic acid) combined with the homogeneous nucleation of GSA alone. Major growth of the particles was predicted to occur by the same organic vapour at concentrations of (1-2) ×1012cm-3. The pre-existing core and soot mode concentrations had opposite trend on the NUP formation, and maximum NUP formation was predicted if a diesel particle filter (DPF) was used. On the other hand, NUP formation was ceased if the GSA concentration was less than 1010cm-3 which suggests, based on the measurements, the usage of biofuel to prevent volatile particles in diesel exhaust.

  5. Continuous volatile fatty acid production from waste activated sludge hydrolyzed at pH 12.

    PubMed

    Yang, Xue; Wan, Chunli; Lee, Duu-Jong; Du, Maoan; Pan, Xiangliang; Wan, Fang

    2014-09-01

    This study adopted rapid alkaline treatment at pH 12 to hydrolyze 66% of total chemical oxygen demands. Then the hydrolyzed liquor was fermented in a continuous-flow stirred reactor to produce volatile fatty acids (VFAs) at 8-h hydraulic retention time and at 35 °C. The maximum VFA productivity reached 365 mg VFAs g(-1) volatile suspended solids in a 45-d operation, with most produced VFAs being acetate and propionate, principally produced by protein degradation. The Bacteroidia, ?-proteobacteria and the Clostridia were identified to be the classes correlating with the fermentation processes. The fermented liquor was applied to denitrifying phosphorus removal process as alternative carbon source after excess phosphorus and nitrogen being recycled via struvite precipitation. Fermented liquors from alkaline hydrolysis-acid fermentation on waste activated sludge are a potential renewable resource for applications that need organic carbons. PMID:24630368

  6. Protocol for the collection and analysis of volatile POHCs (Principal Organic Hazardous Constituents) using VOST (Volatile Organic Sampling Train)

    NASA Astrophysics Data System (ADS)

    Hansen, E. M.

    1984-03-01

    An operating protocol for sampling and analysis of voltatile organic constituents of flue gas from hazardous waste incinerators or other similar combustor systems using the Volatile Organic Sampling Train (VOST) is presented. It is intended to be used for guidance by personnel of the regulatory groups, personnel associated with engineering research and development, and the regulated community. The document is in two parts. Part A describes the key components of the train, the procedures for preparing the sorbent materials, and procedures for sample collection using the VOST. Part B describes the procedures for analyzing VOST sorbent cartridges for volatile principal organic hazardous constituents (POHCs) using purge-trap-desorb gas chromatography/mass spectrometry (P-T-D GC/MS). Quality control procedures are presented in both parts.

  7. Effects of NOx on the volatility of secondary organic aerosol from isoprene photooxidation

    SciTech Connect

    Xu, Lu; Kollman, Matthew S.; Song, Chen; Shilling, John E.; Ng, L. N.

    2014-01-28

    The effects of NOx on the volatility of the secondary organic aerosol (SOA) formed from isoprene photooxidation are investigated in environmental chamber experiments. Two types of experiments are performed. In HO2-dominant experiments, organic peroxy radicals (RO2) primarily react with HO2. In mixed experiments, RO2 reacts through multiple pathways. The volatility and oxidation state of isoprene SOA is sensitive to and displays a non-linear dependence on NOx levels. When initial NO/isoprene ratio is approximately 3 (ppbv:ppbv), SOA are shown to be most oxidized and least volatile, associated with the highest SOA yield. A High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) is applied to characterize the key chemical properties of aerosols. While the composition of SOA in mixed experiments does not change substantially over time, SOA become less volatile and more oxidized as oxidation progresses in HO2-dominant experiments. Analysis of the SOA composition suggests that the further reactions of organic peroxides and alcohols may produce carboxylic acids, which might play a strong role in SOA aging.

  8. Using volatile fatty acid relationships to predict anaerobic digester failure

    SciTech Connect

    Hill, D.T.; Cobb, S.A.; Bolte, J.P.

    1987-01-01

    During recent years, a number of observations have been made in the literature regarding the level and ratio of certain organic acids and the correlation of these acid relationships with anaerobic digester performance, either complete failure or operation in a stressed state. It is an accepted fact that levels of organic acid are important in digestion for two reasons: (a) organic acids (particularly acetic) are the immediate precursors in the metabolic chain leading to methane formation and (b) if present in high concentration, acids are known to cause stress in the microbial population and can ultimately lead to complete process failure. The recent literature (approximately the last 7 years) was searched for digester performance data and organic acid levels. Seventy observations were used in arriving at a relationship between acetic acid level and propionic to acetic acid ratio and digester failure or success. Methane productivity (L CH4/g VS added) was used as the parameter determining digester performance. A definite trend was recognized that suggests acetic acid levels in excess of 800 mg/L or a propionic to acetic acid ratio greater than 1.4 indicate impending digester failure. A laboratory scale study was then conductd to verify this phenomenon. (Refs. 22).

  9. Volatile organic compounds in selected micro-environments

    Microsoft Academic Search

    Andrea Hinwood; Henry Berko; Drew Farrar; Ian Galbally

    2006-01-01

    A program of sampling for volatile organic compounds (VOCs) in ambient air was undertaken in selected locations and micro-environments in Perth, Western Australia to characterise concentrations of target VOCs and to determine the relative strength of the contributing sources to ambient air in different micro-environments in a major Australian city. Twenty-seven locations were sampled and, of the forty-one target compounds,

  10. Distribution of volatile organic chemicals in outdoor and indoor air

    NASA Technical Reports Server (NTRS)

    Shah, Jitendra J.; Singh, Hanwant B.

    1988-01-01

    The EPA volatile organic chemistry (VOC) national ambient data base (Shah, 1988) is discussed. The 320 chemicals included in the VOC data base are listed. The methods used to obtain the data are reviewed and the availability, accessibility, and operation of the data base are examined. Tables of the daily outdoor concentrations for 66 chemicals and the daily indoor concentrations for 35 chemicals are presented.

  11. Microbial Volatile Organic Compound Emission Rates and Exposure Model

    Microsoft Academic Search

    M. Y. Menetrez; K. K. Foarde

    2002-01-01

    This paper presents the results from a study that examined microbial volatile organic compound (MVOC) emissions from six fungi and one bacterial species (Streptomyces spp.) commonly found in indoor environments. Data are presented on peak emission rates from inoculated agar plates loaded with surface growth, ranging from 33.5 ?g·m–2 per 24 h (Cladosporium sphaerospermum) to 515 ?g·m–2 per 24 h

  12. Degradation of volatile organic compounds with thermally activated persulfate oxidation

    Microsoft Academic Search

    Kun-Chang Huang; Zhiqiang Zhao; George E. Hoag; Amine Dahmani; Philip A. Block

    2005-01-01

    This study investigated the extent and treatability of the degradation of 59 volatile organic compounds (VOCs) listed in the EPA SW-846 Method 8260B with thermally activated persulfate oxidation. Data on the degradation of the 59 VOCs (in mixture) reacted with sodium persulfate in concentrations of 1gl?1 and 5gl?1 and at temperatures of 20°C, 30°C, and 40°C were obtained. The results

  13. Trees and VOCs: Measuring volatile organic compounds from urban forests

    NSDL National Science Digital Library

    Institute of Arctic and Alpine Research (INSTAAR) at the University of Colorado-Boulder

    This web site describes a research project to measure volatile organic compounds emitted from species of trees and shrubs found in urban areas. Topics include a description of the project and a section on trees and air quality. A page updated each month or so reports field and lab work on the project. There is also a glossary, profiles of community partners, and profiles of the scientists and students involved in the project.

  14. New graphene fiber coating for volatile organic compounds analysis.

    PubMed

    Zhang, GuoJuan; Guo, XiaoXi; Wang, ShuLing; Wang, XueLan; Zhou, YanPing; Xu, Hui

    2014-10-15

    In the work, a novel graphene-based solid phase microextraction-gas chromatography/mass spectrometry method was developed for the analysis of trace amount of volatile organic compounds in human exhaled breath vapor. The graphene fiber coating was prepared by a one-step hydrothermal reduction reaction. The fiber with porous and wrinkled structure exhibited excellent extraction efficiency toward eight studied volatile organic compounds (two n-alkanes, five n-aldehydes and one aromatic compound). Meanwhile, remarkable thermal and mechanical stability, long lifespan and low cost were also obtained for the fiber. Under the optimal conditions, the developed method provided low limits of detection (1.0-4.5ngL(-1)), satisfactory reproducibility (3.8-13.8%) and acceptable recoveries (93-122%). The method was applied successfully to the analysis of breath samples of lung cancer patients and healthy individuals. The unique advantage of this approach includes simple setup, non-invasive analysis, cost-efficient and sufficient sensitivity. The proposed method supply us a new possibility to monitor volatile organic compounds in human exhaled breath samples. PMID:25171504

  15. Analyses of volatile organic compounds from human skin

    PubMed Central

    Gallagher, M.; Wysocki, C.J.; Leyden, J.J.; Spielman, A.I.; Sun, X.; Preti, G.

    2008-01-01

    Summary Background Human skin emits a variety of volatile metabolites, many of them odorous. Much previous work has focused upon chemical structure and biogenesis of metabolites produced in the axillae (underarms), which are a primary source of human body odour. Nonaxillary skin also harbours volatile metabolites, possibly with different biological origins than axillary odorants. Objectives To take inventory of the volatile organic compounds (VOCs) from the upper back and forearm skin, and assess their relative quantitative variation across 25 healthy subjects. Methods Two complementary sampling techniques were used to obtain comprehensive VOC profiles, viz., solid-phase micro extraction and solvent extraction. Analyses were performed using both gas chromatography/mass spectrometry and gas chromatography with flame photometric detection. Results Nearly 100 compounds were identified, some of which varied with age. The VOC profiles of the upper back and forearm within a subject were, for the most part, similar, although there were notable differences. Conclusions The natural variation in nonaxillary skin odorants described in this study provides a baseline of compounds we have identified from both endogenous and exogenous sources. Although complex, the profiles of volatile constituents suggest that the two body locations share a considerable number of compounds, but both quantitative and qualitative differences are present. In addition, quantitative changes due to ageing are also present. These data may provide future investigators of skin VOCs with a baseline against which any abnormalities can be viewed in searching for biomarkers of skin diseases. PMID:18637798

  16. Preliminary evaluation of selected in situ remediation technologies for Volatile Organic Compound contamination at Arid sites

    SciTech Connect

    Lenhard, R.J.; Gerber, M.A.; Amonette, J.E.

    1992-10-01

    To support the Volatile Organic Compounds-Arid Site (VOC-Arid) Integrated Demonstration (ID) in its technical, logistical, institutional, and economical testing of emerging environmental management and restoration technologies. Pacific Northwest Laboratory(a) is evaluating several in situ remediation technologies for possible inclusion in the demonstration. The evaluations are made with respect to the initial focus of the VOC-Arid ID: the carbon tetrachloride contamination at the Hanford Site, where it was disposed to the vadose zone along with other volatile and nonvolatile organic wastes. heavy metals, acids. and radionuclides. The purposes of this report are (1) to identify candidate in situ technologies for inclusion in the program, (2) to evaluate the candidate technologies based on their potential applicability to VOC contamination at arid sites and geologic conditions representative of the ID host site (i.e., Hanford Site), and (3) to prioritize those technologies for future US Department of Energy (DOE) support.

  17. A two-dimensional volatility basis set – Part 2: Diagnostics of organic-aerosol evolution

    E-print Network

    Donahue, N. M.

    We discuss the use of a two-dimensional volatility-oxidation space (2-D-VBS) to describe organic-aerosol chemical evolution. The space is built around two coordinates, volatility and the degree of oxidation, both of which ...

  18. Volatile organic compounds in the environment: A multimedia perspective

    SciTech Connect

    Cohen, Y. [Univ. of California, Los Angeles, CA (United States). Dept. of Chemical Engineering

    1996-12-31

    The environment is a complex system of interacting environmental media. Pollutants do not stay in the medium where they originate but move across environmental phase boundaries. The distribution of pollutants throughout the various environmental compartments (for example, air, water, soil, and biota) is the result of complex physical, chemical, and biological processes. The resulting environmental and human health risks depend upon the degree of exposure of human and ecological receptors, via multiple pathways, to these chemicals. Thus, environmental pollution is a multimedia problem. Volatile organic compounds (VOCs), in particular, are very mobile in the environment. For example, VOCs which are initially present in the soil or water media can readily volatilize to the atmosphere where they can be transported over significant distances from the source location. In this paper an overview is presented of VOC sources, VOC ambient levels, the multimedia distribution of VOCs in the environment, and multipathway exposure to VOCs.

  19. Supplementary Material for "Quantitative Estimates of the Volatility of Ambient Organic Aerosol"

    E-print Network

    Meskhidze, Nicholas

    as to be generally consistent with the high Hvap values determined for low volatility dicarboxylic acids (Cappa et al., 2007), where a value of 181 kJ/mol was observed for sebacic acid (a 10- carbon dicarboxylic acid.1 of the main text. A global definition of non-volatile material is derived by taking these distributions (where

  20. Removal and recovery of inhibitory volatile fatty acids from mixed acid fermentations by conventional electrodialysis.

    PubMed

    Jones, Rhys Jon; Massanet-Nicolau, Jaime; Guwy, Alan; Premier, Giuliano C; Dinsdale, Richard M; Reilly, Matthew

    2015-08-01

    Hydrogen production during dark fermentation is inhibited by the co-production of volatile fatty acids (VFAs) such as acetic and n-butyric acid. In this study, the effectiveness of conventional electrodialysis (CED) in reducing VFA concentrations in model solutions and hydrogen fermentation broths is evaluated. This is the first time CED has been reported to remove VFAs from hydrogen fermentation broths. During 60min of operation CED removed up to 99% of VFAs from model solutions, sucrose-fed and grass-fed hydrogen fermentation broths, containing up to 1200mgl(-1) each of acetic acid, propionic acid, i-butyric acid, n-butyric acid, i-valeric acid, and n-valeric acid. CED's ability to remove VFAs from hydrogen fermentation broths suggests that this technology is capable of improving hydrogen yields from dark fermentation. PMID:25898090

  1. Analysis of Organic Acids.

    ERIC Educational Resources Information Center

    Griswold, John R.; Rauner, Richard A.

    1990-01-01

    Presented are the procedures and a discussion of the results for an experiment in which students select unknown carboxylic acids, determine their melting points, and investigate their solubility behavior in water and ethanol. A table of selected carboxylic acids is included. (CW)

  2. Volatile organic compounds in the unsaturated zone from radioactive wastes

    USGS Publications Warehouse

    Baker, Ronald J.; Andraski, Brian J.; Stonestrom, David A.; Luo, Wentai

    2012-01-01

    Volatile organic compounds (VOCs) are often comingled with low-level radioactive wastes (LLRW), but little is known about subsurface VOC emanations from LLRW landfills. The current study systematically quantified VOCs associated with LLRW over an 11-yr period at the USGS Amargosa Desert Research Site (ADRS) in southwestern Nevada. Unsaturated-zone gas samples of VOCs were collected by adsorption on resin cartridges and analyzed by thermal desorption and GC/MS. Sixty of 87 VOC method analytes were detected in the 110-m-thick unsaturated zone surrounding a LLRW disposal facility. Chlorofluorocarbons (CFCs) were detected in 100% of samples collected. Chlorofluorocarbons are powerful greenhouse gases, deplete stratospheric ozone, and are likely released from LLRW facilities worldwide. Soil-gas samples collected from a depth of 24 m and a horizontal distance 100 m south of the nearest waste-disposal trench contained >60,000 ppbv total VOCs, including >37,000 ppbv CFCs. Extensive sampling in the shallow unsaturated zone (0–2 m deep) identified areas where total VOC concentrations exceeded 5000 ppbv at the 1.5-m depth. Volatile organic compound concentrations exceeded background levels up to 300 m from the facility. Maximum vertical diffusive fluxes of total VOCs were estimated to be 1 g m-2 yr-1. Volatile organic compound distributions were similar but not identical to those previously determined for tritium and elemental mercury. To our knowledge, this study is the first to characterize the unsaturated zone distribution of VOCs emanating from a LLRW landfill. Our results may help explain anomalous transport of radionuclides at the ADRS and elsewhere.

  3. Adsorption of selected volatile organic vapors on multiwall carbon nanotubes.

    PubMed

    Shih, Yang-hsin; Li, Mei-syue

    2008-06-15

    Carbon nanotubes are expected to play an important role in sensing, pollution treatment and separation techniques. This study examines the adsorption behaviors of volatile organic compounds (VOCs), n-hexane, benzene, trichloroethylene and acetone on two multiwall carbon nanotubes (MWCNTs), CNT1 and CNT2. Among these VOCs, acetone exhibits the highest adsorption capacity. The highest adsorption enthalpies and desorption energies of acetone were also observed. The strong chemical interactions between acetone and both MWCNTs may be the result from chemisorption on the topological defects. The adsorption heats of trichloroethylene, benzene, and n-hexane are indicative of physisorption on the surfaces of both MWCNTs. CNT2 presents a higher adsorption capacity than CNT1 due to the existence of an exterior amorphous carbon layer on CNT2. The amorphous carbon enhances the adsorption capacity of organic chemicals on carbon nanotubes. The morphological and structure order of carbon nanotubes are the primary affects on the adsorption process of organic chemicals. PMID:17980962

  4. Detection of volatile organic compounds using porphyrin derivatives.

    PubMed

    Dunbar, A D F; Brittle, S; Richardson, T H; Hutchinson, J; Hunter, C A

    2010-09-16

    Seven different porphyrin compounds have been investigated as colorimetric gas sensors for a wide range of volatile organic compounds. The porphyrins examined were the free base and Mg, Sn, Zn, Au, Co, and Mn derivatives of 5,10,15,20-tetrakis[3,4-bis(2-ethylhexyloxy)phenyl]-21H,23H-porphine. Chloroform solutions of these materials were prepared and changes in their absorption spectra induced by exposure to various organic compounds measured. The porphyrins that showed strong responses in solution were selected, and Langmuir-Blodgett films were prepared and exposed to the corresponding analytes. This was done to determine whether they are useful materials for solid state thin film colorimetric vapor sensors. Porphyrins that readily coordinate extra ligands are shown to be suitable materials for colorimetric volatile organic compound detectors. However, porphyrins that already have bound axial ligands when synthesized only show a sensor response to those analytes that can substitute these axial ligands. The Co porphyrin displays a considerably larger response than the other porphyrins investigated which is attributed to a switch between Co(II) and Co(III) resulting in a large spectral change. PMID:20735119

  5. Evanescent wave sensor for detecting volatile organic compounds

    NASA Astrophysics Data System (ADS)

    Goswami, Kisholoy; Prohaska, John D.; Menon, Anil; Mendoza, Edgar A.; Lieberman, Robert A.

    1999-02-01

    This work evaluates the usefulness of an intracore long period grating (LPG) structure on optical fiber for constructing a fiber-optic chemical sensor. The sensor response relies on the evanescent field interaction of core- guided light with volatile organic compounds (VOCs) surrounding the long period gratings. The LPGs were coated with proprietary chemical indicators having strong affinities for VOCs. The feasibility of this approach was tested by using representative hydrocarbons and halohydrocarbons in parts per thousand to parts per million concentrations. Test results demonstrate that LPGs offer the promise for sensitively detecting VOCs in air, water, and soil matrices.

  6. Oxidation of volatile organic compounds on AlâOâ, Pd\\/AlâOâ, and PdO\\/AlâOâ catalysts

    Microsoft Academic Search

    E. Cordi; J. L. Falconer

    1996-01-01

    Temperature-programmed desorption (TPD) and oxidation (TPO) were used to study the decomposition and oxidation of methanol, ethanol, acetaldehyde, formic acid, and acetic acid on AlâOâ, Pd\\/AlâOâ, and PdO\\/AlâOâ catalysts. The oxidation and decomposition rates were much higher on Pd\\/AlâOâ than on AlâOâ, even though the volatile organic compounds (VOCs) were adsorbed on the AlâOâ support in both cases. The VOCs

  7. Concentrating aqueous volatile fatty acid salt solutions using a tertiary amine mixture 

    E-print Network

    Gaskin, David J

    1997-01-01

    be used to selectively remove water from a fermentation broth thus concentrating calcium acetate, propionate, and butyrate. Compared to competing technologies that extract undissociated acids from a volatile fatty acid fermentation broth, extracting water...

  8. Volatile fatty acid fermentation of lime-treated bagasse by rumen microorganisms 

    E-print Network

    Lee, Chang-Ming

    1993-01-01

    ) to provide necessary nutrients. The volatile fatty acid (VFA) product concentrations, yields and proportions of each acid for six different bagasse concentrations (10, 20, 35, 50, 75, and 100 g/L) are reported. Bagasse was treated with calcium hydroxide...

  9. Origin and utilization of volatile fatty acids in the rat C. RMSY C. DEMIGN F. CHARTIER

    E-print Network

    Paris-Sud XI, Université de

    Origin and utilization of volatile fatty acids in the rat C. RÉMÉSY C. DEMIGNÉ F. CHARTIER differences in the caecum of the rat have been compared for volatile fatty acids (VFA) and for electrolytes plasma was increased in fed as in starved rats, showing that acetyl CoA synthe- tase was still active

  10. MAGNESIUM ABSORPTION IN THE CCUM OF RATS RELATED TO VOLATILE FATTY ACIDS PRODUCTION

    E-print Network

    Paris-Sud XI, Université de

    MAGNESIUM ABSORPTION IN THE CÆCUM OF RATS RELATED TO VOLATILE FATTY ACIDS PRODUCTION Y. RAYSSIGUIER RELATIONS ENTRE L'ABSORPTION C,4ECALE DE MAGNESIUM CHEZ LE RAT ET LA PRODUCTION D'ACIDES GRAS VOLATILS le rat. Nous avons voulu préciser le rôle du caecum dans la digestibilité du magnésium chez des rats

  11. Phase partitioning and volatility of secondary organic aerosol components formed from ?-pinene ozonolysis and OH oxidation: the importance of accretion products and other low volatility compounds

    NASA Astrophysics Data System (ADS)

    Lopez-Hilfiker, F. D.; Mohr, C.; Ehn, M.; Rubach, F.; Kleist, E.; Wildt, J.; Mentel, Th. F.; Carrasquillo, A.; Daumit, K.; Hunter, J.; Kroll, J. H.; Worsnop, D.; Thornton, J. A.

    2015-02-01

    We measured a large suite of gas and particle phase multi-functional organic compounds with a Filter Inlet for Gases and AEROsols (FIGAERO) coupled to a high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS) developed at the University of Washington. The instrument was deployed on environmental simulation chambers to study monoterpene oxidation as a secondary organic aerosol (SOA) source. We focus here on results from experiments utilizing an ionization method most selective towards acids (acetate negative ion proton transfer), but our conclusions are based on more general physical and chemical properties of the SOA. Hundreds of compounds were observed in both gas and particle phases, the latter being detected upon temperature programmed thermal desorption of collected particles. Particulate organic compounds detected by the FIGAERO HR-ToF-CIMS are highly correlated with, and explain at least 25-50% of, the organic aerosol mass measured by an Aerodyne Aerosol Mass Spectrometer (AMS). Reproducible multi-modal structures in the thermograms for individual compounds of a given elemental composition reveal a significant SOA mass contribution from large molecular weight organics and/or oligomers (i.e. multi-phase accretion reaction products). Approximately 50% of the HR-ToF-CIMS particle phase mass is associated with compounds having effective vapor pressures 4 or more orders of magnitude lower than commonly measured monoterpene oxidation products. The relative importance of these accretion-type and other extremely low volatility products appears to vary with photochemical conditions. We present a desorption temperature based framework for apportionment of thermogram signals into volatility bins. The volatility-based apportionment greatly improves agreement between measured and modeled gas-particle partitioning for select major and minor components of the SOA, consistent with thermal decomposition during desorption causing the conversion of lower volatility components into the detected higher volatility compounds.

  12. Determination of organic acids (Câ-Cââ) in the atmosphere, motor exhaust, and engine oils

    Microsoft Academic Search

    Kimitaka Kawamura; Lai Ling Ng; Isaac R. Kaplan

    1985-01-01

    A method is described for the determination of volatile organic acids in the atmosphere, motor exhausts, and engine oils. Atmospheric organic acids were collected on a KOH impregnated quartz filter and derivatized to p-bromophenacyl esters. The derivatives were analyzed by high-resolution capillary gas chromatography and gas chromatography-mass spectrometry. Câ-Cââ aliphatic organic acids and benzoic acid were detected in Los Angeles

  13. 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

  14. Meeting new air standards with a volatile organic treatment train

    SciTech Connect

    Bowers, J.S.; Dennison, D.; May, G.

    1995-02-01

    The U.S. Environmental Protection Agency (EPA) issued the second phase of the organic air emission standards for hazardous waste treatment, storage, and disposal facilities (TSDFs) and hazardous waste generators in December 1994. These standards (referred to as the Subpart CC standards) are designed to further reduce organic air emissions from hazardous waste management activities. To comply with these new air standards, Lawrence Livermore National Laboratory (LLNL) is designing a volatile organic removal and destruction treatment train to modify its existing Waste Water Treatment Tank Farm (hereafter called Tank Farm). LLNL`s Tank Farm consists of six, 7,000-L open-top tanks used to store and treat aqueous low-level radioactive, mixed, and hazardous waste before discharging it to the local publicly owned treatment works. The waste stored and treated in the tanks have elevated volatile organic constituent (VOC) concentrations. According to the Subpart CC standards, tanks handling waste with similar VOC concentrations must be retrofitted with a cover and an emission control device for cover openings that achieves at least a 95% reduction in the total organic content of the vented gas stream. However, LLNL concluded that the removal and destruction of VOCs from waste before they enter the Tank Farm would demonstrate compliance with the Subpart CC standards more effectively and be more cost effective than installation of air emission control devices on the Tank Farm. LLNL has designed this removal and destruction technique to consist of an air stripper, high-efficiency particulate air (HEPA) filter, catalytic oxidizer, scrubber, and mist eliminator.

  15. Screening analysis of volatile organic contaminants in commercial inorganic coagulants used for drinking water treatment

    Microsoft Academic Search

    Michael Petri; Jia-Qian Jiang; Matthias Maier

    2009-01-01

    A method for quality screening is suggested to detect volatile impurities in inorganic coagulants that are used for drinking water treatment. Static headspace gas chromatography with mass spectrometry detection (HS–GCMS) is sensitive and selective to detect volatiles in low concentrations. This study has discovered that volatile organic impurities are detectable in ferric and aluminium-based coagulants which are used for drinking

  16. Fungal volatile organic compounds and their role in ecosystems.

    PubMed

    Hung, Richard; Lee, Samantha; Bennett, Joan W

    2015-04-01

    All odorants are volatile organic compounds (VOCs), i.e., low molecular weight compounds that easily evaporate at normal temperatures and pressure. Fungal VOCs are relatively understudied compared to VOCs of bacterial, plant, or synthetic origin. Much of the research to date on fungal VOCs has focused on their food and flavor properties, their use as indirect indicators of fungal growth in agriculture, or their role as semiochemicals for insects. In addition, research into fungal volatiles has also taken place to monitor spoilage, for purposes of chemotaxonomy, for use in biofilters and for biodiesel, to detect plant and animal disease, for "mycofumigation," and with respect to plant health. As methods for the analysis of gas phase molecules have improved, it has become apparent that fungal VOC are more chemically varied and more biologically active than has generally been realized. In particular, there is increasing data that show that fungal VOCs frequently mediate interactions between organisms within and across different ecological niches. The goal of this mini review is to orchestrate data on fungal VOCs obtained from disparate disciplines as well as to draw attention to the ecological importance of fungal VOCs in signaling between different species. Technologies and approaches that are common in one area of research are often unknown in others, and the study of fungal VOCs would benefit from more cross talk between subdisciplines. PMID:25773975

  17. Role of volatile fatty acids in colonization resistance to Clostridium difficile.

    PubMed Central

    Rolfe, R D

    1984-01-01

    The in vitro inhibition of Clostridium difficile by volatile fatty acids was correlated with the pH and concentrations of volatile fatty acids in the ceca of hamsters of different ages. The concentrations of cecal volatile fatty acids increased with the age of the animals. Maximum concentrations of individual volatile fatty acids were attained when the animals were ca. 19 days old, with acetic, propionic, and butyric acids occurring in the highest concentrations (72, 16, and 32 microequivalents/g of cecum, respectively). The cecal pH was approximately the same in hamsters of all ages (pH 6.6 to 7.0). Only butyric acid reached a concentration in the ceca of hamsters which was inhibitory to the in vitro multiplication of C. difficile. This inhibitory concentration was attained when the animals were ca. 19 days of age. When mixtures of volatile fatty acids were prepared at concentrations equal to those present in the ceca of hamsters, there was a direct correlation between the in vitro inhibitory activity of the volatile fatty acids and the susceptibility of hamsters 4 days of age or older to C. difficile intestinal colonization. The resistance of hamsters less than 4 days of age to C. difficile intestinal colonization appears to be due to factors other than volatile fatty acids. PMID:6735467

  18. Cyclodextrin-based microsensors for volatile organic compounds

    SciTech Connect

    Swanson, B.; Johnson, S.; Shi, J.; Yang, Xiaoguang

    1997-10-01

    Host-guest chemistry and self-assembly techniques are being explored to develop species selective thin-films for real-time sensing of volatile organic compounds (VOCs). Cyclodextrin (CD) and calixarene (CA) molecules are known to form guest-host inclusion complexes with a variety of organic molecules. Through the control of the cavity size and chemical functionality on the rims of these bucket-like molecules, the binding affinities for formation of inclusion complexes can be controlled and optimized for specific agents. Self-assembly techniques are used to covalently bond these reagent molecules to the surface of acoustic transducers to create dense, highly oriented, and stable thin films. Self-assembly techniques have also been used to fabricate multilayer thin film containing molecular recognition reagents through alternating adsorption of charged species in aqueous solutions. Self-assembly of polymeric molecules of the SAW device was also explored for fabricating species selective interfaces.

  19. An automated GC/MS system for the analysis of volatile and semi-volatile organic compounds in water.

    PubMed

    Vickers, A K; Wright, L M

    1993-01-01

    This paper describes a GC/MS system capable of performing Volatile Organic Analysis on liquids, solids, and air. When combined with a syringe auto-injector, the system is completely automated for both volatile and semi-volatile analyses. An OI Analytical Model 4551 Vial Multisampler and an OI Analytical DPM-16 Multisampler are interfaced and then connected to an OI Analytical Model 4560 Sample Concentrator, an HP Model 5971 MSD, an HP Model 7673 Auto-Injector, and an HP Model 5890 Series II GC to form a multi-tasking GC/MS system. This system is shown to allow greater versatility in the laboratory. PMID:18924968

  20. Emission of volatile organic compounds during composting of municipal solid wastes

    Microsoft Academic Search

    Dimitris P Komilis; Robert K Ham; Jae K Park

    2004-01-01

    The objective of this study was to identify and quantify volatile and semi-volatile organic compounds (VOCs) produced during composting of the organic fraction of municipal solid wastes (MSW). A laboratory experiment was conducted using organic components of MSW that were decomposed under controlled aerobic conditions. Mixed paper primarily produced alkylated benzenes, alcohols and alkanes. Yard wastes primarily produced terpenes, alkylated

  1. Nano-Ag-Nafion modified Pt electrode for oxidation of volatile organic compounds: an electrochemical study.

    PubMed

    Muthuraman, G; Chung, Sang Joon; Moon, Il Shik

    2011-08-01

    In this work, we describe Nano-Ag-Nafion coated pt electrode for oxidation of volatile organic compound (VOC), here acetaldehyde. Electrochemically synthesized Nano-Ag-Nafion film on Pt was analyzed by electrochemically in various electrolyte solutions like nitric acid, sulfuric acid, potassium nitrate, and potassium hydroxide for its stability. High stability of Nano-Ag-Nafion film appeared in potassium hydroxide medium among electrolyte solutions studied. Electrocatalysis of acetaldehyde was occurred only in acid and neutral medium. A catalytic oxidative peak during cathodic voltammetric reduction scan was observed at 1.75 V, which, unusual redox behavior, follows EC' reaction path way between electrogenerated Ag(II) and acetaldehyde. For Nano-Ag potential applicability, a calibration plot was drawn from various concentration range of acetaldehyde to check the maximum concentration level of acetaldehyde degradation in air. PMID:22103205

  2. 77 FR 38761 - Approval and Promulgation of Air Quality Implementation Plans; Indiana; Volatile Organic...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-29

    ...Approval and Promulgation of Air Quality Implementation Plans; Indiana; Volatile Organic Compounds; Consumer Products AGENCY: Environmental Protection...and other restrictions on consumer products that are sold, supplied,...

  3. HS-SPME\\/GC–MS analysis of volatile and semi-volatile organic compounds emitted from municipal sewage sludge

    Microsoft Academic Search

    Urszula Kotowska; Maciej ?alikowski; Valery A. Isidorov

    The aim of the research involved identification and semi-quantitative determination of unknown volatile and semi-volatile\\u000a organic compounds emitted to air by sewage sludge formed in the process of municipal wastewater treatment in a sewage treatment\\u000a plant. Samples taken directly after completion of the technological process as well as the sludge stored on the premise of\\u000a the sewage treatment plant were

  4. Measurement of volatile organic compounds in human blood.

    PubMed Central

    Ashley, D L; Bonin, M A; Cardinali, F L; McCraw, J M; Wooten, J V

    1996-01-01

    Volatile organic compounds (VOCs) are an important public health problem throughout the developed world. Many important questions remain to be addressed in assessing exposure to these compounds. Because they are ubiquitous and highly volatile, special techniques must be applied in the analytical determination of VOCs. The analytical methodology chosen to measure toxicants in biological materials must be well validated and carefully carried out; poor quality assurance can lead to invalid results that can have a direct bearing on treating exposed persons. The pharmacokinetics of VOCs show that most of the internal dose of these compounds is quickly eliminated, but there is a fraction that is only slowly removed, and these compounds may bioaccumulate. VOCs are found in the general population at the high parts-per-trillion range, but some people with much higher levels have apparently been exposed to VOC sources away from the workplace. Smoking is the most significant confounder to internal dose levels of VOCs and must be considered when evaluating suspected cases of exposure. PMID:8933028

  5. Evaluation of volatile organic emissions from hazardous waste incinerators.

    PubMed Central

    Sedman, R M; Esparza, J R

    1991-01-01

    Conventional methods of risk assessment typically employed to evaluate the impact of hazardous waste incinerators on public health must rely on somewhat speculative emissions estimates or on complicated and expensive sampling and analytical methods. The limited amount of toxicological information concerning many of the compounds detected in stack emissions also complicates the evaluation of the public health impacts of these facilities. An alternative approach aimed at evaluating the public health impacts associated with volatile organic stack emissions is presented that relies on a screening criterion to evaluate total stack hydrocarbon emissions. If the concentration of hydrocarbons in ambient air is below the screening criterion, volatile emissions from the incinerator are judged not to pose a significant threat to public health. Both the screening criterion and a conventional method of risk assessment were employed to evaluate the emissions from 20 incinerators. Use of the screening criterion always yielded a substantially greater estimate of risk than that derived by the conventional method. Since the use of the screening criterion always yielded estimates of risk that were greater than that determined by conventional methods and measuring total hydrocarbon emissions is a relatively simple analytical procedure, the use of the screening criterion would appear to facilitate the evaluation of operating hazardous waste incinerators. PMID:1954928

  6. Macromolecular Organic Acids in the Murchison Meteorite

    NASA Astrophysics Data System (ADS)

    Watson, J. S.; Sephton, M. A.; Gilmour, I.

    2005-03-01

    This study has detected bound organic acids within the Murchison meteorite organic macromolecule. Benzoic acid was the most abundant compound; other abundant compounds include C1 and C2 benzoic acids. Their origin and significance will be discussed.

  7. Catalytic oxidation process cleans volatile organics from exhaust

    SciTech Connect

    Haggin, J.

    1994-06-27

    Unsteady-state catalytic oxidation is the basis of a technology now becoming available in the US for removing volatile organic compounds (VOCs) from industrial exhaust streams. The technology originated in Russia and is being developed for the US market by Monsanto Enviro-Chem Systems, St. Louis. At least 149 of the 189 pollutants identified by EPA are VOCs. EPA estimates that the initial cost to industry for equipment to remove the hazardous materials will be about $350 million. The expected annual maintenance bill to treat the major pollution sources is about $182 million. Catalytic oxidizers are applicable to most, but not all, VOC removal applications. The advantages in most cases are VOC removal efficiencies of at least 99%, half the energy requirement of other systems, low operating temperatures, stable operation with variable flow rates and VOC concentrations, and low capital and operating costs.

  8. Subjective reactions to volatile organic compounds as air pollutants

    NASA Astrophysics Data System (ADS)

    Mølhave, Lars; Grønkjær, John; Larsen, Søren

    Human subjective reactions to indoor air pollution in the form of volatile organic compounds in five concentrations ? mg m -3 were examined in a climate chamber under controlled conditions in a balanced experimental design. The reactions of 25 subjects were registered in two questionnaires containing 25 and six questions and on a linear analogue rating scale. Each subject was tested for one day including four runs in each of the five treatments of 50 min duration. Dose effects were found for perceived odour intensity at 3 mgm -3. Air quality, need for ventilation, irritation of eye and nose showed significant effect at 8 mg m -3. Significant reduced well being was reported at 25 mgm -3. The analyses indicated that lower threshold for some of these effects would have been found if more subjects or longer exposure-times had been used. Gender, age, occupational education and smoking habits were co-factors for many of the symptoms reported.

  9. Laboratory methods for volatile organic compounds evolved in mineralization studies

    SciTech Connect

    Hickey, W.J.; Arnold, S.M.; Moran, B.N. [Univ. of Wisconsin, Madison, WI (United States)

    1995-11-01

    A system to study mineralization of volatile organic compounds (VOCs) was developed using commercially available solid-phase VOC traps and impingers to collect CO{sub 2} as well as VOCs breaking out from the solid-phase trap. The efficiencies of VOC traps containing activated charcoal (AC) or graphitized carbon black (GCB) for absorbing [{sup 14}C]trichloroethylene ([{sup 14}C]TCE) and {sup 14}CO{sub 2} were evaluated, and approaches for minimizing VOC losses from reaction vessels were established. Mass balances showed AC and GCB absorbed similar amounts of [{sup 14}C]TCE. However, GCB had no detectable {sup 14}CO{sub 2} retention, whereas AC absorbed about 7% of the {sup 14}CO{sub 2}. Because {sup 14}CO{sub 2} absorption could influence the interpretation of mineralization experiments, GCB was concluded to be the better VOC-trapping matrix.

  10. Apparatus for sensing volatile organic chemicals in fluids

    DOEpatents

    Hughes, Robert C.; Manginell, Ronald P.; Jenkins, Mark W.; Kottenstette, Richard; Patel, Sanjay V.

    2005-06-07

    A chemical-sensing apparatus is formed from the combination of a chemical preconcentrator which sorbs and concentrates particular volatile organic chemicals (VOCs) and one or more chemiresistors that sense the VOCs after the preconcentrator has been triggered to release them in concentrated form. Use of the preconcentrator and chemiresistor(s) in combination allows the VOCs to be detected at lower concentration than would be possible using the chemiresistor(s) alone and further allows measurements to be made in a variety of fluids, including liquids (e.g. groundwater). Additionally, the apparatus provides a new mode of operation for sensing VOCs based on the measurement of decay time constants, and a method for background correction to improve measurement precision.

  11. Detection of volatile organic compounds using surface enhanced Raman scattering

    SciTech Connect

    Chang, A S; Maiti, A; Ileri, N; Bora, M; Larson, C C; Britten, J A; Bond, T C

    2012-03-22

    The authors present the detection of volatile organic compounds directly in their vapor phase by surface-enhanced Raman scattering (SERS) substrates based on lithographically-defined two-dimensional rectangular array of nanopillars. The type of nanopillars is known as the tapered pillars. For the tapered pillars, SERS enhancement arises from the nanofocusing effect due to the sharp tip on top. SERS experiments were carried out on these substrates using various concentrations of toluene vapor. The results show that SERS signal from a toluene vapor concentration of ppm level can be achieved, and the toluene vapor can be detected within minutes of exposing the SERS substrate to the vapor. A simple adsorption model is developed which gives results matching the experimental data. The results also show promising potential for the use of these substrates in environmental monitoring of gases and vapors.

  12. Nanoenabled microelectromechanical sensor for volatile organic chemical detection

    NASA Astrophysics Data System (ADS)

    Zuniga, Chiara; Rinaldi, Matteo; Khamis, Samuel M.; Johnson, A. T.; Piazza, Gianluca

    2009-06-01

    A nanoenabled gravimetric chemical sensor prototype based on the large scale integration of single-stranded DNA (ss-DNA) decorated single-walled carbon nanotubes (SWNTs) as nanofunctionalization layer for aluminum nitride contour-mode resonant microelectromechanical (MEM) gravimetric sensors has been demonstrated. The capability of two distinct single strands of DNA bound to SWNTs to enhance differently the adsorption of volatile organic compounds such as dinitroluene (simulant for explosive vapor) and dymethyl-methylphosphonate (simulant for nerve agent sarin) has been verified experimentally. Different levels of sensitivity (17.3 and 28 KHz ?m2/fg) due to separate frequencies of operation (287 and 450 MHz) on the same die have also been shown to prove the large dynamic range of sensitivity attainable with the sensor. The adsorption process in the ss-DNA decorated SWNTs does not occur in the bulk of the material, but solely involves the surface, which permits to achieve 50% recovery in less than 29 s.

  13. Indoor Volatile Organic Compounds and Chemical Sensitivity Reactions

    PubMed Central

    Win-Shwe, Tin-Tin; Arashidani, Keiichi; Kunugita, Naoki

    2013-01-01

    Studies of unexplained symptoms observed in chemically sensitive subjects have increased the awareness of the relationship between neurological and immunological diseases due to exposure to volatile organic compounds (VOCs). However, there is no direct evidence that links exposure to low doses of VOCs and neurological and immunological dysfunction. We review animal model data to clarify the role of VOCs in neuroimmune interactions and discuss our recent studies that show a relationship between chronic exposure of C3H mice to low levels of formaldehyde and the induction of neural and immune dysfunction. We also consider the possible mechanisms by which VOC exposure can induce the symptoms presenting in patients with a multiple chemical sensitivity. PMID:24228055

  14. Source fingerprints for receptor modeling of volatile organics

    SciTech Connect

    Scheff, P.A. (Illinois Institute of Chicago (USA)); Wadden, R.A.; Bates, B.A. (Univ. of Illinois, Chicago (USA)); Aronian, P.F. (UOP Inc., Des Plaines, IL (USA))

    1989-04-01

    The development of receptor models for the determination of the sources of an ambient air pollution requires that the composition of the pollutant at the point of emissions be known. For this study, composition information for 10 sources of volatile organic compounds (VOC) were evaluated and source fingerprints developed. The source categories include motor vehicles, gasoline vapor, petroleum refineries, architectural coatings, graphic arts, waste-water treatment, vapor degreasing, dry cleaning, automobile assembly (including body painting), and polyethylene production. The fingerprints are presented for a group of 23 compounds. These compounds were selected for a variety of reasons including ease of measurement in the ambient environment, compound toxicity, reactivity, and usefulness in previous receptor modeling applications. In general, the data for sources of VOC are remarkably consistent from study to study. Because the profiles for many of the sources of VOC are controlled by physical and chemical process (e.g. combustion) and not raw material composition, the fingerprints have general applicability.

  15. Volatile organic compound (VOC) control in ethylene plants

    SciTech Connect

    Grover, R.; Gomaa, H.M. [M.W. Kellogg Co., Houston, TX (United States)

    1994-12-31

    Volatile Organic Compounds (VOC) are compounds of carbon that combine with nitrogen oxides and other airborne chemicals, in the presence of sunlight (photochemically), to form ozone, which is a primary component of smog. Some common VOC include: benzene, toluene, xylene, naphtha, ethylene oxide, methyl ethyl ketone, acetone, and 1,3-Butadiene. Pollution of the atmosphere by VOC has been a subject of major concern. Therefore, VOC emissions are attracting increasing concern from public and government agencies. Ethylene plants have many multiple sources of VOC emissions. These sources can be divided into point emission sources, both continuous and intermittent, and fugitive emission sources. This paper discusses VOC emissions and controls for ethylene plants. The impact of environmental regulations are discussed with respect to new and existing ethylene plants. Typical VOC emission rates are quantified. Commercially available and emerging control technologies are reviewed.

  16. Emissions of biogenic volatile organic compounds & their photochemical transformation

    NASA Astrophysics Data System (ADS)

    Yu, Zhujun; Hohaus, Thorsten; Tillmann, Ralf; Andres, Stefanie; Kuhn, Uwe; Rohrer, Franz; Wahner, Andreas; Kiendler-Scharr, Astrid

    2015-04-01

    Natural and anthropogenic activities emit volatile organic compounds (VOC) into the atmosphere. While it is known that land vegetation accounts for 90% of the global VOC emissions, only a few molecules' emission factors are understood. Through VOCs atmospheric oxidation intermediate products are formed. The detailed chemical mechanisms involved are insufficiently known to date and need to be understood for air quality management and climate change predictions. In an experiment using a PTR-ToF-MS with the new-built plant chamber SAPHIR-PLUS in Forschungszentrum Juelich, biogenic emissions of volatile organic compounds (BVOC) from Quercus ilex trees were measured. The BVOC emissions were dominated by monoterpenes, minor emissions of isoprene and methanol were also observed with the overall emission pattern typical for Quercus ilex trees in the growing season. Monoterpenes and isoprene emissions showed to be triggered by light. Additionally, their emissions showed clear exponential temperature dependence under constant light condition as reported in literature. As a tracer for leaf growth, methanol emission showed an abrupt increase at the beginning of light exposure. This is explained as instantaneous release of methanol produced during the night once stomata of leaves open upon light exposure. Emission of methanol showed a near linear increase with temperature in the range of 10 to 35 °C. BVOC were transferred from the plant chamber PLUS to the atmospheric simulation chamber SAPHIR, where their oxidation products from O3 oxidation were measured with PTR-ToF-MS. Gas phase oxidation products such as acetone and acetaldehyde were detected. A quantitative analysis of the data will be presented, including comparison of observations to the Master Chemical Mechanism model.

  17. Characterization of microbial species in a regenerative bio-filter system for volatile organic compound removal

    Microsoft Academic Search

    Wen-Hsuan Huang; Zhiqiang Wang; Geetika Choudhary; Beverly Guo; Jianshun Zhang; Dacheng Ren

    2012-01-01

    Effective removal of volatile organic compounds is critical for indoor air quality control. The performance of traditional technologies of volatile organic compound removal is limited by inadequate selection of filter media, poor airflow management inside the cleaning devices, insufficient catalytic reaction surface area, and poor distribution of UV light irradiation. In comparison, the relatively new regenerative air filtration systems use

  18. Ion-trap detection of volatile organic compounds in alveolar breath

    Microsoft Academic Search

    M. Phillips; J. Greenberg

    1992-01-01

    We describe a method for the collection and microanalysis of the volatile organic compounds in human breath. A transportable apparatus supplies subjects with purified air and samples their alveolar breath; the volatile organic compounds are captured in an adsorptive trap containing activated carbon and molecular sieve. The sample is thermally desorbed from the trap in an automated microprocessor-controlled device, concentrated

  19. 40 CFR 60.112 - Standard for volatile organic compounds (VOC).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Standard for volatile organic compounds (VOC). 60.112 Section 60.112 Protection of Environment...1978 § 60.112 Standard for volatile organic compounds (VOC). (a) The owner or operator of any storage vessel to...

  20. 40 CFR 60.112a - Standard for volatile organic compounds (VOC).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Standard for volatile organic compounds (VOC). 60.112a Section 60.112a Protection...Standard for volatile organic compounds (VOC). (a) The owner or operator of...vapor recovery system which collects all VOC vapors and gases discharged from the...

  1. 40 CFR 60.312 - Standard for volatile organic compounds (VOC).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Standard for volatile organic compounds (VOC). 60.312 Section 60.312 Protection...Standard for volatile organic compounds (VOC). (a) On and after the date on...cause the discharge into the atmosphere of VOC emissions from any metal furniture...

  2. TECHNICAL ASSISTANCE DOCUMENT: THE USE OF PORTABLE VOLATILE ORGANIC COMPOUND ANALYZERS FOR LEAK DETECTION

    EPA Science Inventory

    This document has been prepared for the purpose of providing guidance on the selection and use of portable volatile organic compound analyzers for monitoring process leaks. Specifically the types of volatile organic compound analyzers capable of performing U.S. EPA Method 21 dete...

  3. ASSESSMENT OF VOLATILE ORGANIC EMISSIONS FROM A PETROLEUM REFINERY LAND TREATMENT SITE

    EPA Science Inventory

    A field assessment was performed to measure the emissions of volatile organics from a petroleum refinery landtreatment site. As part of the study, the emissions of total volatile organics from surface-applied and subsurface-injected oily sludge were measured over a five week peri...

  4. DEVELOPMENT OF THE VOLATILE ORGANIC SAMPLING TRAIN (VOST) FOR USE IN DETERMINING INCINERATOR EFFICIENCY

    EPA Science Inventory

    The paper discusses the development, initial evaluation, and field application to incinerators of a new sampling train for volatile organic species. The Volatile Organic Sampling Train (VOST) is a simple portable device, combining Tenax and Tenax/charcoal cartridges as collection...

  5. Time Dependence of Blood Concentrations during and after Exposure to a Mixture of Volatile Organic Compounds

    Microsoft Academic Search

    David L. Ashley; James D. Prah

    1997-01-01

    Volatile organic compounds constitute a group of important environmental pollutants that have been associated with the constellation of symptoms known as sick building syndrome. An understanding of the kinetics of uptake and elimination of volatile organic compounds is important for the proper interpretation of the internal dose concentrations of people exposed to these compounds. Blood concentrations measured before, during, and

  6. Volatile organic compounds in storm water from a parking lot

    USGS Publications Warehouse

    Lopes, T.J.; Fallon, J.D.; Rutherford, D.W.; Hiatt, M.H.

    2000-01-01

    A mass balance approach was used to determine the most important nonpoint source of volatile organic compounds (VOCs) in storm water from an asphalt parking lot without obvious point sources (e.g., gasoline stations). The parking lot surface and atmosphere are important nonpoint sources of VOCs, with each being important for different VOCs. The atmosphere is an important source of soluble, oxygenated VOCs (e.g., acetone), and the parking lot surface is an important source for the more hydrophobic VOCs (e.g., benzene). VOCs on the parking lot surface appear to be concentrated in oil and grease and organic material in urban particles (e.g., vehicle soot). Except in the case of spills, asphalt does not appear to be an important source of VOCs. The uptake isotherm of gaseous methyl tert-butyl ether on urban particles indicates a mechanism for dry deposition of VOCs from the atmosphere. This study demonstrated that a mass balance approach is a useful means of understanding non-point-source pollution, even for compounds such as VOCs, which are difficult to sample.A mass balance approach was used to determine the most important nonpoint source of volatile organic compounds (VOCs) in storm water from an asphalt parking lot without obvious point sources (e.g., gasoline stations). The parking lot surface and atmosphere are important nonpoint sources of VOCs, with each being important for different VOCs. The atmosphere is an important source of soluble, oxygenated VOCs (e.g., acetone), and the parking lot surface is an important source for the more hydrophobic VOCs (e.g., benzene). VOCs on the parking lot surface appear to be concentrated in oil and grease and organic material in urban particles (e.g., vehicle soot). Except in the case of spills, asphalt does not appear to be an important source of VOCs. The uptake isotherm of gaseous methyl tert-butyl ether on urban particles indicates a mechanism for dry deposition of VOCs from the atmosphere. This study demonstrated that a mass balance approach is a useful means of understanding non-point-source pollution, even for compounds such as VOCs, which are difficult to sample.

  7. UNDERSTANDING THE CONTRIBUTIONS AND INTERACTIONS OF SUGARS, ACIDS AND AROMA VOLATILES TO OVERALL TOMATO FLAVOR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The contribution and interaction of sugars, acids and volatiles to tomato (Lycoperscon esculentum Mill.) flavor is little understood. Coarsely chopped deodorized tomato puree was spiked with different levels of individual food grade volatiles, reported to contribute to tomato flavor, as well as two...

  8. Using electromagnetic induction technology to predict volatile fatty acid, source area differences

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Subsurface sampling techniques have been adapted to measure manure accumulation on feedlot surface. Objectives of this study were to determine if sensor data could be used to predict differences in volatile fatty acids (VFA) and other volatiles produced on the feedlot surface three days following a...

  9. Effect of acidic seed on biogenic secondary organic aerosol growth

    NASA Astrophysics Data System (ADS)

    Czoschke, Nadine M.; Jang, Myoseon; Kamens, Richard M.

    Secondary organic aerosol (SOA) growth in the presence of acid aerosols was studied in twin 500 l Teflon bags and in a 4 m flow reactor. In Teflon bags, isoprene, acrolein and ?-pinene were all made to react individually with ozone and exposed to either acid or non-acid inorganic seed aerosols to determine the effect of acid-catalyzed heterogeneous reactions on SOA growth. ?-Pinene and ozone were made to react in a flow reactor to assess the immediate effect of mixing an acid aerosol with SOA at high and low relative humidity levels. In all cases, exposure to acid seed aerosol increased the amount of SOA mass produced. Fourier transform infrared spectra of the SOA in acid systems confirmed the transformation of carbonyl functional groups through acid-catalyzed heterogeneous reactions when SOAs formed in acidic environments or were exposed to acidic aerosols. Organic products initially produced from ozonation in the gas phase partition onto the inorganic seed aerosol and react heterogeneously with an acid catalyst forming low vapor pressure products. These acid-catalyzed heterogeneous reactions are implicated in generating the increased SOA mass observed in acidic aerosol systems as they transform predominantly gas phase compounds of high volatility into low vapor pressure predominantly particle phase products.

  10. Pretreatment of macroalgae for volatile fatty acid production.

    PubMed

    Pham, Thi Nhan; Um, Youngsoon; Yoon, Hyon Hee

    2013-10-01

    In this study, a novel method was proposed for the biological pretreatment of macroalgae (Laminaria japonica, Pachymeniopsis elliptica, and Enteromorpha crinita) for production of volatile fatty acid (VFA) by anaerobic fermentation. The amount of VFA produced from 40 g/L of L. japonica increased from 8.3 g/L (control) to 15.6 g/L when it was biologically pretreated with Vibrio harveyi. The biological treatment of L. japonica with Vibrio spp. was most effective likely due to the alginate lyase activity of Vibrio spp. However, a considerable effect was also observed after biological pretreatment of P. elliptica and E. crinita, which are red and green algae, respectively. Alkaline pretreatment of 40 g/L of L. japonica with 0.5 N NaOH resulted in an increase of VFA production to 12.2 g/L. These results indicate that VFA production from macroalgae can be significantly enhanced using the proposed biological pretreatments. PMID:23942360

  11. Extraction of organic acids using imidazolium-based ionic liquids and their toxicity to Lactobacillus rhamnosus

    Microsoft Academic Search

    Michiaki Matsumoto; Kenji Mochiduki; Kei Fukunishi; Kazuo Kondo

    2004-01-01

    In situ extractive fermentation of lactic acid using organic solvents has already been heavily investigated. Now ionic liquids are emerging as alternative solvents for volatile organic compounds traditionally used in liquid–liquid extraction. In this paper, we examine whether imidazolium-based ionic liquids can replace conventional organic solvents in the extractive fermentation of lactate by investigating their extraction behaviors and solvent toxicity.

  12. Chemical oxidation of volatile and semi-volatile organic compounds in soil

    SciTech Connect

    Gates, D.D.; Siegrist, R.L.; Cline, S.R.

    1995-06-01

    Subsurface contamination with fuel hydrocarbons or chlorinated hydrocarbons is prevalent throughout the Department of Energy (DOE) complex and in many sites managed by the Environmental Protection Agency (EPA) Superfund program. The most commonly reported chlorinated hydrocarbons (occurring > 50% of DOE contaminated sites) were trichloroethylene (TCE), 1, 1, 1,-trichloroethane (TCA), and tetrachloroethylene (PCE) with concentrations in the range of 0.2 {mu}g/kg to 12,000 mg/kg. The fuel hydrocarbons most frequently reported as being present at DOE sites include aromatic compounds and polyaromatic compounds such as phenanthrene, pyrene, and naphthalene. The primary sources of these semi-volatile organic compounds (SVOCs) are coal waste from coal fired electric power plants used at many of these facilities in the past and gasoline spills and leaks. Dense non-aqueous phase liquids (DNAPLs) can migrate within the subsurface for long periods of time along a variety of pathways including fractures, macropores, and micropores. Diffusion of contaminants in the non-aqueous, aqueous, and vapor phase can occur from the fractures and macropores into the matrix of fine-textured media. As a result of these contamination processes, removal of contaminants from the subsurface and the delivery of treatment agents into and throughout contaminated regions are often hindered, making rapid and extensive remediation difficult.

  13. Volatile organic compounds and trace metal level in some beers collected from Romanian market

    NASA Astrophysics Data System (ADS)

    Voica, Cezara; Kovacs, Melinda; Vadan, Marius

    2013-11-01

    Beer is one of the most popular beverages at worldwide level. Through this study fifteen different types of beer collected from Romanian market were analysed in order to evaluate their mineral, trace element as well the their organic content. Importance of such characterization of beer samples is supported by the fact that their chemical composition can affect both taste and stability of beer, as well the consumer health. Minerals and trace elements analysis were performed on ICP-MS while organic compounds analysis was done through GC-MS. Through ICP-MS analysis, elements as Ca, Na, K and Mg were evidenced at mg?kg-1 order while elements as Cr, Ba, Co, Ni were detected at lower level. After GC-MS analysis the major volatile compounds that were detected belong to alcohols namely ethanol, propanol, isobutanol, isoamyl alcohol and linalool. Selected fatty acids and esters were evidenced also in the studied beer samples.

  14. Biogenic volatile organic compound emissions from vegetation fires

    PubMed Central

    CICCIOLI, PAOLO; CENTRITTO, MAURO; LORETO, FRANCESCO

    2014-01-01

    The aim of this paper was to provide an overview of the current state of the art on research into the emission of biogenic volatile organic compounds (BVOCs) from vegetation fires. Significant amounts of VOCs are emitted from vegetation fires, including several reactive compounds, the majority belonging to the isoprenoid family, which rapidly disappear in the plume to yield pollutants such as secondary organic aerosol and ozone. This makes determination of fire-induced BVOC emission difficult, particularly in areas where the ratio between VOCs and anthropogenic NOx is favourable to the production of ozone, such as Mediterranean areas and highly anthropic temperate (and fire-prone) regions of the Earth. Fire emissions affecting relatively pristine areas, such as the Amazon and the African savannah, are representative of emissions of undisturbed plant communities. We also examined expected BVOC emissions at different stages of fire development and combustion, from drying to flaming, and from heatwaves coming into contact with unburned vegetation at the edge of fires. We conclude that forest fires may dramatically change emission factors and the profile of emitted BVOCs, thereby influencing the chemistry and physics of the atmosphere, the physiology of plants and the evolution of plant communities within the ecosystem. PMID:24689733

  15. 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.

  16. Branched chain amino acids as source of specific branched chain volatile fatty acids during the fermentation process of fish sauce

    Microsoft Academic Search

    N. G. Sanceda; E. Suzuki; T. Kurata

    2003-01-01

    Summary.  ?The source of the formation of branched chain volatile fatty acids (VFA) in fish sauce was investigated. Certain branched\\u000a VFA were derived from the degradation of specific amino acids as iso-butyric acid from valine and iso-valeric acid from leucine. Short and long straight chain VFA were significantly higher in the linoleic acid added sample\\u000a than in the control but did

  17. Branched-chain and aromatic amino acid catabolism into aroma volatiles in Cucumis melo L. fruit

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The unique aroma of melons (Cucumis melo L., Cucurbitaceae) is composed of many volatile compounds biosynthetically derived from fatty-acids, carotenoids, amino-acids as well as terpenes. Incubation of melon fruit cubes with amino- and a-keto acids led to the enhanced formation of aroma compounds be...

  18. Volatile fatty acid fermentation of AFEX-treated newspaper and bagasse by rumen microorganisms

    E-print Network

    Blasig, Jorge Dari?o

    1991-01-01

    VOLATILE FATTY ACID FERMENTATION OF AFEX-TREATED NEWSPAPER AND BAGASSE BY RUMEN MICROORGANISMS A Thesis by JORGE DARIO BLAS IG Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillement of the requirements... for the degree of MASTER OF SCIENCE August 1991 Major Subject: Agricultural Engineering VOLATILE FATTY ACID FERMENTATION OF APEX-TREATED NEWSPAPER AND BAGASSE BY RUMEN MICROORGANISMS A Thesis by JORGE DARIO BLASIG Approved as to style and content by...

  19. Volatile fatty acid fermentation of lime-treated biomass by rumen microorganisms

    E-print Network

    Rapier, Charles Robert

    1995-01-01

    VOLATILE FATTY ACID FERMENTATION OF LIME-TREATED BIOMASS BY RUMEN MICROORGANISMS A Thesis by CHARLES ROBERT RAPIER Submitted to the Office of Cnaduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE August 1995 Major Subject: Chemical Engineeriug VOLATILE FATTY ACID FERMENTATION OF LIME-TREATED BIOMASS BY RUMEN MICROORGANISMS A Thesis by CHARLES ROBERT RAPIER Submitted to Texas AkM University in partial fultillment...

  20. Volatility and oxidative aging of aqueous maleic acid aerosol droplets and the dependence on relative humidity.

    PubMed

    Dennis-Smither, Benjamin J; Marshall, Frances H; Miles, Rachael E H; Preston, Thomas C; Reid, Jonathan P

    2014-07-31

    The microphysical structure and heterogeneous oxidation by ozone of single aerosol particles containing maleic acid (MA) has been studied using aerosol optical tweezers and cavity enhanced Raman spectroscopy. The evaporation rate of MA from aqueous droplets has been measured over a range of relative humidities and the pure component vapor pressure determined to be (1.7 ± 0.2) × 10(-3) Pa. Variation in the refractive index (RI) of an aqueous MA droplet with relative humidity (RH) allowed the subcooled liquid RI of MA to be estimated as 1.481 ± 0.001. Measurements of the hygroscopic growth are shown to be consistent with equilibrium model predictions from previous studies. Simultaneous measurements of the droplet composition, size, and refractive index have been made during ozonolysis at RHs in the range 50-80%, providing insight into the volatility of organic products, changes in the droplet hygroscopicity, and optical properties. Exposure of the aqueous droplets to ozone leads to the formation of products with a wide range of volatilities spanning from involatile to volatile. Reactive uptake coefficients show a weak dependence on ozone concentration, but no dependence on RH or salt concentration. The time evolving RI depends significantly on the RH at which the oxidation proceeds and can even show opposing trends; while the RI increases with ozone exposure at low relative humidity, the RI decreases when the oxidation proceeds at high relative humidity. The variations in RI are broadly consistent with a framework for predicting RIs for organic components published by Cappa et al. ( J. Geophys. Res. 2011 , 116 , D15204 ). Once oxidized, particles are shown to form amorphous phases on drying rather than crystallization, with slow evaporation kinetics of residual water. PMID:25003240

  1. Compositing water samples for analysis of volatile organic compounds

    USGS Publications Warehouse

    Lopes, T.J.; Fallon, J.D.; Maluk, T.L.

    2000-01-01

    Accurate mean concentrations of volatile organic compounds (VOCs) can easily and economically be obtained from a single VOC analysis by using proven methods of collecting representative, discrete water samples and compositing them with a gas-tight syringe. The technique can be used in conjunction with chemical analysis by a conventional laboratory, field-portable equipment, or a mobile laboratory. The type of mean concentration desired depends on the objectives of monitoring. For example, flow-weighted mean VOC concentrations can be used to estimate mass loadings in wastewater and urban storm water, and spatially integrated mean VOC concentrations can be used to assess sources of drinking water (e.g., reservoirs and rivers). The mean error in a discrete sample due to compositing is about 2% for most VOC concentrations greater than 0.1 ??g/L. The total error depends on the number of discrete samples comprising the composite sample and precision of the chemical analysis.Accurate mean concentrations of volatile organic compounds (VOCs) can easily and economically be obtained from a single VOC analysis by using proven methods of collecting representative, discrete water samples and compositing them with a gas-tight syringe. The technique can be used in conjunction with chemical analysis by a conventional laboratory, field-portable equipment, or a mobile laboratory. The type of mean concentration desired depends on the objectives of monitoring. For example, flow-weighted mean VOC concentrations can be used to estimate mass loadings in wastewater and urban storm water, and spatially integrated mean VOC concentrations can be used to assess sources of drinking water (e.g., reservoirs and rivers). The mean error in a discrete sample due to compositing is about 2% for most VOC concentrations greater than 0.1 ??g/L. The total error depends on the number of discrete samples comprising the composite sample and precision of the chemical analysis.Researchers are able to derive accurate values for the mean concentration of VOCs from a single VOC analysis using established techniques for the collection of representative, discrete water samples. Such samples are then composited with a gas-tight syringe. This methodology can be employed in conjunction with chemical assessment using a conventional laboratory, field-portable equipment, or a mobile laboratory. Estimates of mass loadings in wastewater and urban storm runoff can be generated using values for the flow-weighted mean VOC concentrations. Spatially integrated mean VOC concentrations are useful for the evaluation of drinking waters. Factors that influence the value for the total error are identified.

  2. Emission and Chemical Transformation of Biogenic Volatile Organic Compounds (echo)

    NASA Astrophysics Data System (ADS)

    Koppmann, R.; Hoffmann, T.; Kesselmeier, J.; Schatzmann, M.

    Forests are complex sources of biogenic volatile organic compounds (VOC) in the planetary boundary layer. The impact of biogenic VOC on tropospheric photochem- istry, air quality, and the formation of secondary products affects our climate on a regional and global scale but is far from being understood. A considerable lack of knowledge exists concerning a forest stand as a net source of reactive trace com- pounds, which are transported directly into the planetary boundary layer (PBL). In particular, little is known about the amounts of VOC which are processed within the canopy. The goal of ECHO, which is presented in this poster, is to investigate these questions and to improve our understanding of biosphere-atmosphere interactions and their effects on the PBL. The investigation of emissions, chemical processing and vertical transport of biogenic VOC will be carried out in and above a mixed forest stand in Jülich, Germany. A large set of trace gases, free radicals and meteorologi- cal parameters will be measured at different heights in and above the canopy, covering concentrations of VOC, CO, O3, organic nitrates und NOx as well as organic aerosols. For the first time concentration profiles of OH, HO2, RO2 und NO3 radicals will be measured as well together with the actinic UV radiation field and photolysis frequen- cies of all relevant radical precursors (O3, NO2, peroxides, oxygenated VOC). The different tasks of the field experiments will be supported by simulation experiments investigating the primary emission and the uptake of VOC by the plants in stirred tank reactors, soil parameters and soil emissions in lysimeter experiments, and the chem- ical processing of the trace gases as observed in and above the forest stand in the atmosphere simulation chamber SAPHIR. The planning and interpretation of the field experiments is supported by simulations of the field site in a wind tunnel.

  3. 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.

  4. Formaldehyde and other volatile organic chemical emissions in four FEMA temporary housing units.

    PubMed

    Maddalena, Randy; Russell, Marion; Sullivan, Douglas P; Apte, Michael G

    2009-08-01

    Indoor concentrations of 33 volatile organic chemicals were measured in four unoccupied temporary housing units (THUs) belonging to the U.S. Federal Emergency Management Administration (FEMA). The highest level contaminants in the THUs include formaldehyde, acetic acid, and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TXIB) with median concentrations of 440, 425, and 36 ppb, respectively. A number of volatile organic compounds (VOCs) were higher than published concentrations in other dwellings, but whole THU emission factors for most chemicals were either lower than or similar to values reported for newly constructed homes. However, several chemicals exceeded previously measured new building emission rates by over a factor of 5. Materials were collected from the THUs, and emission factors were determined using small chambers to identify the potential source of indoor contaminants. The individual materials were grouped by material type, and emissions were used to derive exposure concentrations for comparison to reference values. Using material loading factors and ventilation rates that are relevant to the trailers, all of the material types we tested had at least two chemicals (formaldehyde and nonanal) with derived concentrations in excess of chronic reference exposure levels or odor thresholds. The extensive use of composite wood products, sealants, and vinyl coverings, combined with the low air exchange rates relative to material surface areas, may explain the high concentrations of some VOCs and formaldehyde. PMID:19731654

  5. Volatile organic compounds (VOCs) in photochemically aged air from the Eastern and Western Mediterranean

    NASA Astrophysics Data System (ADS)

    Derstroff, Bettina; Stoenner, Christof; Klüpfel, Thomas; Sauvage, Carina; Crowley, John; Phillips, Gavin; Parchatka, Uwe; Lelieveld, Jos; Williams, Jonathan

    2015-04-01

    In summer 2014 a comprehensively instrumented measurement campaign (CYPHEX) was conducted in northwest Cyprus in order to investigate atmospheric oxidation chemistry in the Mediterranean region. The site was periodically influenced by the northerly Etesian winds advecting air from Eastern Europe (Turkey and Greece) and from westerly winds bringing more photochemically processed emissions from Western Europe (Spain and France). In this study the data from a Proton Transfer Reaction Time of Flight Mass Spectrometer (PTR-TOF-MS) are analyzed. Generally, oxidized volatile organic compounds (OVOCs) such as methanol and acetone were measured in high mixing ratios (max. 9.5 ppb, min. 1.3 ppb, average 3.2 ppb for methanol, max. 7.9 ppb, min. 1.3 ppb, average 2.4 ppb for acetone ) while precursors like propane showed low values (max. 500 ppt). This demonstrates that the air measured was oxidized to a high degree over the Mediterranean Sea. Low values of acetonitrile throughout the campaign indicated no significant influence of biomass burning on the data. Temporal variations in VOC mixing ratios and precursor/product ratios over the campaign can be explained by using the HYSPLIT backward trajectory model which delineated air masses originating from Eastern and Western Europe. Diel variations of reactive VOCs such as isoprene and terpenes were also observed at the site. A sharp increase in isoprene and monoterpenes at circa 9:00 local time indicated that the 600 m hilltop site was influenced by ascending boundary layer air at this time. In this study, particular emphasis is placed on acetic (ethanoic) acid measured by PTR- TOF-MS and calibrated by a permeation source. Acetic acid is an atmospheric oxidation product of multiple volatile organic compounds, emitted directly from vegetation, and found in abundance in the Mediterranean region (max. 2.7 ppb, min. 0.2 ppb, average 0.8 ppb). Acetic acid contributes to the acidity of precipitation in remote areas, can be incorporated into aerosols by adsorption on the surface and thereby alter the activity due to their high polarity. Correlations of acetic acid with peracetic acid, humidity and ozone have been investigated in order to better understand the sources influencing acetic acid at the site and to assess its potential as a marker for Criegee radical chemistry.

  6. Volatile organic compounds in selected micro-environments.

    PubMed

    Hinwood, A L; Berko, H N; Farrar, D; Galbally, I E; Weeks, I A

    2006-04-01

    A program of sampling for volatile organic compounds (VOCs) in ambient air was undertaken in selected locations and micro-environments in Perth, Western Australia to characterise concentrations of target VOCs and to determine the relative strength of the contributing sources to ambient air in different micro-environments in a major Australian city. Twenty-seven locations were sampled and, of the forty-one target compounds, 26 VOCs were detected in the samples collected. The highest concentrations were recorded for benzene, toluene, ethylbenzene, xylenes (BTEX), chloroform and styrene. The maximum 12-h toluene and benzene concentrations observed were from a basement carpark and were 24.7 parts per billion (ppb) and 5.6 ppb, respectively. The maximum xylenes concentration was 29.4 ppb and occurred in a nightclub where styrene was also detected. A factor analysis of the data was undertaken. Two key factors emerge that appear to be associated with petroleum and motor vehicles and environmental tobacco smoke. A third significant occurrence was a high concentration of chloroform that was observed at a sports centre complex with a swimming pool text and was uncorrelated with other compounds in the data set. This study indicates that locations associated with motor vehicles and petrol fuel, tobacco and wood smoke and chlorinated water represent the major risks for personal exposure to VOCs in Perth. PMID:16289288

  7. Modeling Emissions of Volatile Organic Compounds from New Carpets

    SciTech Connect

    Little, J.C.; Hodgson, A.T.; Gadgil, A.J.

    1993-02-01

    A simple model is proposed to account for observed emissions of volatile organic compounds (VOCs) from new carpets. The model assumes that the VOCs originate predominantly in a uniform slab of polymer backing material. Parameters for the model (the initial concentration of a VOC in the polymer, a diffusion coefficient and an equilibrium polymer/air partition coefficient) are obtained from experimental data produced by a previous chamber study. The diffusion coefficients generally decrease as the molecular weight of the VOCs increase, while the polymer/air partition coefficients generally increase as the vapor pressure of the compounds decrease. In addition, for two of the study carpets that have a styrene-butadiene rubber (SBR) backing, the diffusion and partition coefficients are similar to independently reported values for SBR. The results suggest that predictions of VOCs emissions from new carpets may be possible based solely on a knowledge of the physical properties of the relevant compounds and the carpet backing material. However, a more rigorous validation of the model is desirable.

  8. Resonance Raman spectroscopy of volatile organics -- Carbon tetrachloride

    SciTech Connect

    Barletta, R.E.; Veligdan, J.T. [Brookhaven National Lab., Upton, NY (United States). Dept. of Advanced Technology

    1994-09-01

    Volatile organic chemicals are a class of pollutants which are regulated at very low levels by the EPA. Consequently a need exists as a part of site remediation efforts within DOE to develop technologies which will allow for the in situ monitoring of these chemicals. Resonance Raman spectroscopy is a potential technique to accomplish this if the resonance enhancement is sufficiently high. Carbon tetrachloride was selected as a test case. Measurements under resonance conditions at 248 nm showed an enhancement factor of 2 {times} 10{sup 4}. Using this value an estimate of the sensitivity for both in situ and remote monitoring of CCl{sup 4} was made. It was concluded that resonance Raman could be used to detect these chemicals at levels of regulatory interest. Future effort directed towards the development of a suitable probe as well as a field-portable system would be desirable. Such effort could be directed towards the solution of a particular monitoring problem within a DOE waste remediation project. Once developed, however, it should be easily generalized to the analysis of other VOC`s in other environments.

  9. Volatile organic emissions from adhesives with indoor applications

    SciTech Connect

    Girman, J.R.; Hodgson, A.T.; Newton, A.S.; Winkes, A.W.

    1984-02-01

    Studies have shown that volatile organic compounds (VOC) emitted from building materials are a potentially important source of indoor air pollution. In this study, we investigated emissions of VOC from both solvent- and water-based adhesives. Adhesives were applied to an inert substrate and dried for at least a week. VOC were cryogenically trapped and identified by GC-MS or sorbent trapped, solvent extracted, and quantified by GC-FID. Among the compounds emitted by adhesives were toluene, styrene, and a variety of normal, branched, and cyclic alkanes. The measured emission rates ranged from below the limit of detection for some adhesives to a total alkane emission rate of over 700 ..mu..g g/sup -1/h/sup -1/ for a water-based adhesive. A simple, well-mixed tank model was used to assess the potential impacts of the adhesives studied and to demonstrate that adhesives can be significant sources of VOC. 8 references, 1 figure, 2 tables.

  10. Identification and quantification of volatile organic compounds from a dairy

    NASA Astrophysics Data System (ADS)

    Filipy, Jenny; Rumburg, Brian; Mount, George; Westberg, Hal; Lamb, Brian

    Volatile organic compounds (VOCs) that contribute to odor and air quality problems have been identified from the Washington State University Knott Dairy Farm using gas chromatography-mass spectroscopy (GC-MS). Eighty-two VOCs were identified at a lactating cow open stall and 73 were detected from a slurry wastewater lagoon. These compounds included alcohols, aldehydes, ketones, esters, ethers, aromatic hydrocarbons, halogenated hydrocarbons, terpenes, other hydrocarbons, amines, other nitrogen containing compounds, and sulfur-containing compounds. The concentration of VOCs directly associated with cattle waste increased with ambient air temperature, with the highest concentrations present during the summer months. Concentrations of most detected compounds were below published odor detection thresholds. Emission rates of ethanol (1026±513 ?g cow -1 s -1) and dimethyl sulfide (DMS) (13.8±10.3 ?g cow -1 s -1) were measured from the lactating stall area using an atmospheric tracer method and concentrations were plotted using data over a 2-year period. Emission rates of acetone (3.03±0.85 ng cow -1 s -1), 2-butanone (145±35 ng cow -1 s -1), methyl isobutyl ketone (3.46±1.11 ng cow -1 s -1), 2-methyl-3-pentanone (25.1±8.0 ng cow -1 s -1), DMS (2.19±0.92 ng cow -1 s -1), and dimethyl disulfide (DMDS) (16.1±3.9 ng cow -1 s -1) were measured from the slurry waste lagoon using a laboratory emission chamber.

  11. Volatile organic compound monitoring by photo acoustic radiometry

    SciTech Connect

    Sollid, J.E.; Trujillo, V.L.; Limback, S.P.; Woloshun, K.A.

    1995-12-01

    Two methods for sampling and analyzing volatile organics in subsurface pore gas were developed for use at the Hazardous Waste Disposal Site at Los Alamos National Laboratory. One is Thermal Desorption Gas Chromatography Mass Spectrometry (TDGCMS), the other is Photoacoustic Radiometry (PAR). Presented here are two years worth of experience and lessons learned as both techniques matured. The sampling technique is equally as important as the analysis method. PAR is a nondispersive infrared technique utilizing band pass filters in the region from 1 to 15 {mu}m. A commercial instrument, the Model 1302 Multigas Analyzer, made by Bruel and Kjaer, was adapted for field use. To use the PAR there must be some a priori knowledge of the constellation of analytes to be measured. The TDGCMS method is sensitive to 50 analytes. Hence TDGCMS is used in an initial survey of the site to determine what compounds are present and at what concentration. Once the major constituents of the soil-gas vapor plume are known the PAR can be configured to monitor for the five analytes of most interest. The PAR can analyse a sample in minutes, while in the field. The PAR is also quite precise in controlled situations.

  12. Advanced heat pump for the recovery of volatile organic compounds

    SciTech Connect

    Not Available

    1992-03-01

    Emissions of Volatile Organic Compounds (VOC) from stationary industrial and commercial sources represent a substantial portion of the total US VOC emissions. The Toxic-Release Inventory'' of The US Environmental Protection Agency estimates this to be at about 3 billion pounds per year (1987 estimates). The majority of these VOC emissions are from coating processes, cleaning processes, polymer production, fuel production and distribution, foam blowing,refrigerant production, and wood products production. The US Department of Energy's (DOE) interest in the recovery of VOC stems from the energy embodied in the recovered solvents and the energy required to dispose of them in an environmentally acceptable manner. This Phase I report documents 3M's work in close working relationship with its subcontractor Nuclear Consulting Services (Nucon) for the preliminary conceptual design of an advanced Brayton cycle heat pump for the recovery of VOC. Nucon designed Brayton cycle heat pump for the recovery of methyl ethyl ketone and toluene from coating operations at 3M Weatherford, OK, was used as a base line for the work under cooperative agreement between 3M and ODE. See appendix A and reference (4) by Kovach of Nucon. This cooperative agreement report evaluates and compares an advanced Brayton cycle heat pump for solvent recovery with other competing technologies for solvent recovery and reuse. This advanced Brayton cycle heat pump is simple (very few components), highly reliable (off the shelf components), energy efficient and economically priced.

  13. A novel nanostructure for ultrasensitive volatile organic compound sensing

    NASA Astrophysics Data System (ADS)

    Zhao, Huaizhou; Rizal, Binod; Ren, Zhifeng; Naughton, Michael J.; Chiles, Thomas C.; Cai, Dong

    2011-03-01

    We have developed an arrayed nanocoaxial structure for the ultrasensitive sensing detection and identification of volatile organic compounds (VOC) by dielectric impedance spectroscopy. VOC molecules are absorbed into porous dielectric material in the annulus between nanoscale coax electrodes. A theoretical expression for the basic adsorption mechanism agrees with the experimental results. Detection sensitivities at parts-per-billion levels were demonstrated for a variety of VOCs. A limit-of-detection of ethanol reached ~ 100 parts-per-trillion, following a Freundlich power-law isotherm across four decades of ethanol concentration. A linear dependence on VOC dielectric constant was observed. Dielectric impedance nanospectroscopy was also performed by scanning frequency from 10 mHz to 1 MHz, with distinctive spectra of different VOCs discovered. These were utilized to conduct colorimetric identification of VOCs. The results suggest our novel nanocoaxial sensor can be used as a sensitive, broadband, and multimodal sensing platform for chemical detection. The National Cancer Institute CA137681, the Department of Navy, the National Science Foundation PHY-0804718, and the Seaver Institute. Emails: caid@bc.edu; naughton@bc.edu.

  14. Predicting the emission rate of volatile organic compounds fromvinyl flooring

    SciTech Connect

    Cox, Steven S.; Little, John C.; Hodgson, Alfred T.

    2001-03-01

    A model for predicting the rate at which a volatile organic compound (VOC) is emitted from a diffusion-controlled material is validated for three contaminants (n-pentadecane, n-tetradecane, and phenol) found in vinyl flooring (VF). Model parameters are the initial VOC concentration in the material-phase (C{sub 0}), the material/air partition coefficient (K), and the material-phase diffusion coefficient (D). The model was verified by comparing predicted gas-phase concentrations to data obtained during small-scale chamber tests, and by comparing predicted material-phase concentrations to those measured at the conclusion of the chamber tests. Chamber tests were conducted with the VF placed top side up and bottom side up. With the exception of phenol, and within the limits of experimental precision, the mass of VOCs recovered in the gas phase balances the mass emitted from the material phase. The model parameters (C{sub 0}, K, and D) were measured using procedures that were completely independent of the chamber test. Gas- and material-phase predictions compare well to the bottom-side-up chamber data. The lower emission rates for the top-side-up orientation may be explained by the presence of a low-permeability surface layer. The sink effect of the stainless steel chamber surface was shown to be negligible.

  15. Volatile organic compounds adsorption onto neat and hybrid bacterial cellulose

    NASA Astrophysics Data System (ADS)

    Ion, Violeta Alexandra; Pârvulescu, Oana Cristina; Dobre, T?nase

    2015-04-01

    Adsorption dynamics of VOCs (volatile organic compounds) vapour from air streams onto fixed bed adsorbent were measured and simulated under various operation conditions. Isopropanol (IPA) and n-hexane (HEX) were selected as representatives of polar and nonpolar VOCs, whereas bacterial cellulose (BC) and BC incorporated with magnetite nanoparticles (M/BC), were tested as adsorbents. An experimental study emphasizing the influence of air superficial velocity (0.7 cm/s and 1.7 cm/s), operation temperature (30 °C and 40 °C), adsorbate and adsorbent type, on fixed bed saturation curves was conducted. Optimal adsorption performances evaluated in terms of saturation adsorption capacity were obtained for the adsorption of polar compound (IPA) onto M/BC composite (0.805 g/g) and of nonpolar compound (HEX) onto neat BC (0.795 g/g), respectively, at high values of air velocity and operation temperature. A mathematical model including mass balance of VOC species, whose parameters were fitted based on experimental data, was developed in order to predict the fixed bed saturation curves. A 23 statistical model indicating a significant increase in adsorption performances with process temperature was validated under the experimental conditions.

  16. Volatile organic silicon compounds: the most undesirable contaminants in biogases.

    PubMed

    Ohannessian, Aurélie; Desjardin, Valérie; Chatain, Vincent; Germain, Patrick

    2008-01-01

    Recently a lot of attention has been focused on volatile organic silicon compounds (VOSiC) present in biogases. They induce costly problems due to silicate formation during biogas combustion in valorisation engine. The cost of converting landfill gas and digester gas into electricity is adversely affected by this undesirable presence. VOSiC in biogases spark off formation of silicate deposits in combustion chambers. They engender abrasion of the inner surfaces leading to serious damage, which causes frequent service interruptions, thus reducing the economic benefit of biogases. It is already known that these VOSiC originate from polydimethylsiloxanes (PDMS) hydrolysis. PDMS (silicones) are used in a wide range of consumer and industrial applications. PDMS are released into the environment through landfills and wastewater treatment plants. There is a lack of knowledge concerning PDMS biodegradation during waste storage. Consequently, understanding PDMS behaviour in landfill cells and in sludge digester is particularly important. In this article, we focused on microbial degradation of PDMS through laboratory experiments. Preliminary test concerning anaerobic biodegradation of various PDMS have been investigated. Results demonstrate that the biotic step has an obvious influence on PDMS biodegradation. PMID:19029718

  17. Microcantilever sensors coated with a sensitive polyaniline layer for detecting volatile organic compounds.

    PubMed

    Steffens, C; Leite, F L; Manzoli, A; Sandovall, R D; Fatibello, O; Herrmann, P S P

    2014-09-01

    This paper describes a silicon cantilever sensor coated with a conducting polymer layer. The mechanical response (deflection) of the bimaterial (the coated microcantilever) was investigated under the influence of several volatile compounds-methanol, ethanol, acetone, propanol, dichloroethane, toluene and benzene. The variations in the deflection of the coated and uncoated microcantilevers when exposed to volatile organic compounds were evaluated, and the results indicated that the highest sensitivity was obtained with the coated microcantilever and methanol. The uncoated microcantilever was not sensitive to the volatile organic compounds. An increase in the concentration of the volatile organic compound resulted in higher deflections of the microcantilever sensor. The sensor responses were reversible, sensible, rapid and proportional to the volatile concentration. PMID:25924322

  18. Engineered endophytic bacteria improve phytoremediation of water-soluble, volatile, organic pollutants

    Microsoft Academic Search

    Tanja Barac; Safiyh Taghavi; Brigitte Borremans; Ann Provoost; Licy Oeyen; Jan V Colpaert; Jaco Vangronsveld; Daniel van der Lelie

    2004-01-01

    Phytoremediation of highly water soluble and volatile organic xenobiotics is often inefficient because plants do not completely degrade these compounds through their rhizospheres. This results in phytotoxicity and\\/or volatilization of chemicals through the leaves, which can cause additional environmental problems. We demonstrate that endophytic bacteria equipped with the appropriate degradation pathway improve the in planta degradation of toluene. We introduced

  19. On the modification of solid adsorbents with volatile organics II. The role of the layer adsorbed

    Microsoft Academic Search

    M. M. Kope?ni; M. Todorovi?; J. J. ?omor; R. J. Laub

    1988-01-01

    This paper presents a continuation of our research dedicated to solid-adsorbent surface modification with what are commonly regarded as volatile and easily eluted organic compounds. Two porous adsorbents were used: natural zeolite (clinoptilolite) and alumina, while the adsorbates employed were n-hepatane and benzene. The results show that a simple injection of volatile adsorbate greatly alters the solid surface adsorption properties.

  20. VAPORIZATION TECHNIQUE TO MEASURE MUTAGENIC ACTIVITY OF VOLATILE ORGANIC CHEMICALS IN THE AMES/'SALOMELLA' ASSAY

    EPA Science Inventory

    The purpose of the research was to develop and characterize a sensitive test method to detect mutagenic activity of volatile liquid organic chemicals (i.e., volatiles) in the Ames/Salmonella assay. A Tedlar bag vaporization technique was developed which increased contact time bet...

  1. Effects of acetic acid, ethanol, and SO 2 on the removal of volatile acidity from acidic wines by two Saccharomyces cerevisiae commercial strains

    Microsoft Academic Search

    Alice Vilela-Moura; Dorit Schuller; Arlete Mendes-Faia; Manuela Côrte-Real

    2010-01-01

    Herein, we report the influence of different combinations of initial concentration of acetic acid and ethanol on the removal\\u000a of acetic acid from acidic wines by two commercial Saccharomyces cerevisiae strains S26 and S29. Both strains reduced the volatile acidity of an acidic wine (1.0 g?l?1 acetic acid and 11% (v\\/v) ethanol) by 78% and 48%, respectively. Acetic acid removal by

  2. Organic Acid Production by Filamentous Fungi

    E-print Network

    12 Organic Acid Production by Filamentous Fungi Jon K. Magnuson and Linda L. Lasure 1. Introduction Many of the commercial production processes for organic acids are excellent examples of fungal biotechnology. However, unlike penicillin, the organic acids have had a less vis- ible impact on human well

  3. Volatile organic compounds in the strongly fragrant fern genus Melpomene (Polypodiaceae).

    PubMed

    Kessler, M; Connor, E; Lehnert, M

    2015-03-01

    Volatile organic compounds (VOCs) are common among plants, both as attractants for pollinators and as defence against herbivores. While much studied among flowering plants, the prevalence and function of VOCs among ferns is little known. Using headspace sorption and gas chromatography, we analysed the VOCs of dried specimens of six species of grammitid fern (Polypodiaceae), including two species of the genus Melpomene, which is characterised by a distinctive sweet smell. We identified 38 VOCs, including 22 not previously recorded among ferns. The two species of Melpomene had distinct VOC cocktails, including 12 substances not found in the other four studied genera, mainly involving fatty acid derivatives (FADs) and aromatics. We propose that these VOCs have, at least in part, a function in herbivore defence, but note that the VOC bouquet of Melpomene is distinct from that typically found in angiosperms. PMID:25427549

  4. Reactions Between Water Soluble Organic Acids and Nitrates in Atmospheric Aerosols: Recycling of Nitric Acid and Formation of Organic Salts

    SciTech Connect

    Wang, Bingbing; Laskin, Alexander

    2014-03-25

    Atmospheric particles often include a complex mixture of nitrate and secondary organic materials accumulated within the same individual particles. Nitrate as an important inorganic component can be chemically formed in the atmosphere. For instance, formation of sodium nitrate (NaNO3) and calcium nitrate Ca(NO3)2 when nitrogen oxide and nitric acid (HNO3) species react with sea salt and calcite, respectively. Organic acids contribute a significant fraction of photochemically formed secondary organics that can condense on the preexisting nitrate-containing particles. Here, we present a systematic microanalysis study on chemical composition of laboratory generated particles composed of water soluble organic acids and nitrates (i.e. NaNO3 and Ca(NO3)2) investigated using computer controlled scanning electron microscopy with energy dispersive analysis of X-rays (CCSEM/EDX) and Fourier transform infrared micro-spectroscopy (micro-FTIR). The results show that water-soluble organic acids can react with nitrates releasing gaseous HNO3 during dehydration process. These reactions are attributed to acid displacement of nitrate with weak organic acids driven by the evaporation of HNO3 into gas phase due to its relatively high volatility. The reactions result in significant nitrate depletion and formation of organic salts in mixed organic acids/nitrate particles that in turn may affect their physical and chemical properties relevant to atmospheric environment and climate. Airborne nitrate concentrations are estimated by thermodynamic calculations corresponding to various nitrate depletions in selected organic acids of atmospheric relevance. The results indicate a potential mechanism of HNO3 recycling, which may further affect concentrations of gas- and aerosol-phase species in the atmosphere and the heterogeneous reaction chemistry between them.

  5. A dynamic two-dimensional system for measuring volatile organic compound volatilization and movement in soils.

    PubMed

    Allaire, S E; Yates, S R; Ernst, F F; Gan, J

    2002-01-01

    There is an important need to develop instrumentation that allows better understanding of atmospheric emission of toxic volatile compounds associated with soil management. For this purpose, chemical movement and distribution in the soil profile should be simultaneously monitored with its volatilization. A two-dimensional rectangular soil column was constructed and a dynamic sequential volatilization flux chamber was attached to the top of the column. The flux chamber was connected through a manifold valve to a gas chromatograph (GC) for real-time concentration measurement. Gas distribution in the soil profile was sampled with gas-tight syringes at selected times and analyzed with a GC. A pressure transducer was connected to a scanivalve to automatically measure the pressure distribution in the gas phase of the soil profile. The system application was demonstrated by packing the column with a sandy loam in a symmetrical bed-furrow system. A 5-h furrow irrigation was started 24 h after the injection of a soil fumigant, propargyl bromide (3-bromo-1-propyne; 3BP). The experience showed the importance of measuring lateral volatilization variability, pressure distribution in the gas phase, chemical distribution between the different phases (liquid, gas, and sorbed), and the effect of irrigation on the volatilization. Gas movement, volatilization, water infiltration, and distribution of degradation product (Br-) were symmetric around the bed within 10%. The system saves labor cost and time. This versatile system can be modified and used to compare management practices, estimate concentration-time indexes for pest control, study chemical movement, degradation, and emissions, and test mathematical models. PMID:12175024

  6. 40 CFR 60.622 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...SOURCES Standards of Performance for Petroleum Dry Cleaners § 60.622 Standards for volatile...compounds. (a) Each affected petroleum solvent dry cleaning dryer that is installed at a petroleum dry cleaning plant after December 14,...

  7. 40 CFR 60.622 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...SOURCES Standards of Performance for Petroleum Dry Cleaners § 60.622 Standards for volatile...compounds. (a) Each affected petroleum solvent dry cleaning dryer that is installed at a petroleum dry cleaning plant after December 14,...

  8. Adsorption of volatile organic compounds in porous metal-organic frameworks functionalized by polyoxometalates

    SciTech Connect

    Ma Fengji [Key Laboratory of Polyoxometalates Science of the Ministry of Education, College of Chemistry, Northeast Normal University, Changchun 130024 (China); Liu Shuxia, E-mail: liusx@nenu.edu.cn [Key Laboratory of Polyoxometalates Science of the Ministry of Education, College of Chemistry, Northeast Normal University, Changchun 130024 (China); Liang Dadong; Ren Guojian; Wei Feng; Chen Yaguang; Su Zhongmin [Key Laboratory of Polyoxometalates Science of the Ministry of Education, College of Chemistry, Northeast Normal University, Changchun 130024 (China)

    2011-11-15

    The functionalization of porous metal-organic frameworks (Cu{sub 3}(BTC){sub 2}) was achieved by incorporating Keggin-type polyoxometalates (POMs), and further optimized via alkali metal ion-exchange. In addition to thermal gravimetric analysis, IR, single-crystal X-ray diffraction, and powder X-ray diffraction, the adsorption properties were characterized by N{sub 2} and volatile organic compounds (VOCs) adsorption measurements, including short-chain alcohols (C<4), cyclohexane, benzene, and toluene. The adsorption enthalpies estimated by the modified Clausius-Clapeyron equation provided insight into the impact of POMs and alkali metal cations on the adsorption of VOCs. The introduction of POMs not only improved the stability, but also brought the increase of adsorption capacity by strengthening the interaction with gas molecules. Furthermore, the exchanged alkali metal cations acted as active sites to interact with adsorbates and enhanced the adsorption of VOCs. - Graphical Abstract: The adsorption behavior of volatile organic compounds in porous metal-organic frameworks functionalized by polyoxometalates has been systematically evaluated. Highlights: > Functionalization of MOFs was achieved by incorporating Keggin-type POMs. > Introduction of POMs improved the thermal stability and adsorption capacity. > Alkali metal ion-exchange modified the inclusion state and also enhanced the adsorption. > Adsorption enthalpies were estimated to study the impact of POMs and alkali metal cations.

  9. Intermediate-volatility organic compounds: a large source of secondary organic aerosol.

    PubMed

    Zhao, Yunliang; Hennigan, Christopher J; May, Andrew A; Tkacik, Daniel S; de Gouw, Joost A; Gilman, Jessica B; Kuster, William C; Borbon, Agnes; Robinson, Allen L

    2014-12-01

    Secondary organic aerosol (SOA) is a major component of atmospheric fine particle mass. Intermediate-volatility organic compounds (IVOCs) have been proposed to be an important source of SOA. We present a comprehensive analysis of atmospheric IVOC concentrations and their SOA production using measurements made in Pasadena, California during the California at the Nexus of Air Quality and Climate Change (CalNex) study. The campaign-average concentration of primary IVOCs was 6.3 ± 1.9 ?g m(-3) (average ± standard deviation), which is comparable to the concentration of organic aerosol but only 7.4 ± 1.2% of the concentration of speciated volatile organic compounds. Only 8.6 ± 2.2% of the mass of the primary IVOCs was speciated. Almost no weekend/weekday variation in the ambient concentration of both speciated and total primary IVOCs was observed, suggesting that petroleum-related sources other than on-road diesel vehicles contribute substantially to the IVOC emissions. Primary IVOCs are estimated to produce about 30% of newly formed SOA in the afternoon during CalNex, about 5 times that from single-ring aromatics. The importance of IVOCs in SOA formation is expected to be similar in many urban environments. PMID:25375804

  10. Laboratory measurements of emissions of nonmethane volatile organic compounds from biomass burning in Chinese crop residues

    NASA Astrophysics Data System (ADS)

    Inomata, S.; Tanimoto, H.; PAN, X.; Taketani, F.; Komazaki, Y.; Miyakawa, T.; Kanaya, Y.; Wang, Z.

    2014-12-01

    The emission factors (EFs) of volatile organic compounds (VOCs) from the burning of Chinese crop residue were investigated as a function of modified combustion efficiency by the laboratory experiments. The VOCs including acetonitrile, aldehydes/ketones, furan, and aromatic hydrocarbons were monitored by proton-transfer-reaction mass spectrometry. Two samples, wheat straw and rape plant, were burned in dry conditions and for some experiments wheat straw was burned under wet conditions. We compared the present data to the field data reported by Kudo et al. [2014]. The agreement between the field and laboratory data was obtained for aromatics for relatively more smoldering data of dry samples but the field data were slightly underestimated compared with the laboratory data for oxygenated VOCs (OVOCs) and acetonitrile. When the EFs from the burning of wet samples were investigated, the underestimations for OVOCs and acetonitrile were improved compared with the data of dry samples. It may be a property of the burning of crop residue in the region of high temperature and high humidity that some inside parts of piled crop residue and/or the crop residue facing on the ground are still wet. But the ratios for acetic acid/glycolaldehyde was still lower than 1. This may suggest that strong loss processes of acetic acid/glycolaldehyde are present in the fresh plume.Kudo S., H. Tanimoto, S. Inomata, S. Saito, X. L. Pan, Y. Kanaya, F. Taketani, Z. F. Wang, H. Chen, H. Dong, M. Zhang, and K. Yamaji (2014), Emissions of nonmethane volatile organic compounds from open crop residue burning in Yangtze River Delta region, China, J. Geophys. Res. Atmos., 119, 7684-7698, doi: 10.1002/2013JD021044.

  11. 75 FR 24404 - Approval and Promulgation of Air Quality Implementation Plans; Indiana; Volatile Organic Compound...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-05

    ...of Air Quality Implementation Plans; Indiana; Volatile Organic Compound Automobile Refinishing Rules for Indiana AGENCY: Environmental Protection Agency...SUMMARY: EPA is approving into the Indiana State Implementation Plan (SIP)...

  12. RELATIONSHIPS BETWEEN LEVELS OF VOLATILE ORGANIC COMPOUNDS IN AIR AND BLOOD FROM THE GENERAL POPULATION

    EPA Science Inventory

    Background: The relationships between levels of volatile organic compounds (VOCs) in blood and air have not been well characterized in the general population where exposure concentrations are generally at ppb levels. Objectives: This study investigates relationships between ...

  13. NEUROTOXIC EFFECTS OF CONTROLLED EXPOSURE TO A COMPLEX MIXTURE OF VOLATILE ORGANIC COMPOUNDS

    EPA Science Inventory

    Subjective reactions of discomfort, impaired air quality, irritation of mucosal membranes, and impaired memory have been reported in chemically sensitive subjects during exposure to volatile organic compounds (VOC's) found in new buildings. 6 normal healthy male subjects aged 18-...

  14. Impacts of herbaceous bioenergy crops on atmospheric volatile organic composition and potential consequences

    E-print Network

    DeLucia, Evan H.

    Impacts of herbaceous bioenergy crops on atmospheric volatile organic composition and potential, USA Abstract The introduction of new crops to agroecosystems can change the chemical composition compared BVOC emissions from three potential bioenergy crops and estimated their theoretical impacts

  15. BREAKPOINT CHLORINATION/ACTIVATED CARBON TREATMENT: EFFECT ON VOLATILE HALOGENATED ORGANICS

    EPA Science Inventory

    The production and removal of six volatile halogenated organic compounds during treatment of tertiary clarified and filtered wastewater by breakpoint chlorination and activated carbon was examined in a continuous flow pilot plant. Short contact time breakpoint chlorination of fil...

  16. Analysis of breath volatile organic compounds as a screening tool for detection of Tuberculosis in cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    • Keywords: bovine tuberculosis; Mycobacterium bovis; breath analysis; volatile organic compound; gas chromatography; mass spectrometry; NaNose • Introduction: This presentation describes two studies exploring the use of breath VOCs to identify Mycobacterium bovis infection in cattle. • Methods: ...

  17. 76 FR 18893 - Approval and Promulgation of Air Quality Implementation Plans; Ohio; Volatile Organic Compound...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-06

    ...Measures for Lithographic and Letterpress Printing in Cleveland AGENCY: Environmental Protection...approved offset lithographic and letterpress printing volatile organic compound (VOC) rule...revised offset lithographic and letterpress printing rule (OAC 3745-21-22),...

  18. SUPERCRITICAL FLUID EXTRACTION-GAS CHROMATOGRAPHY OF VOLATILE ORGANIC COMPOUNDS (VOC) FROM TENAX DEVICES

    EPA Science Inventory

    The report describes the development and evaluation of on-line supercritical fluid extraction-gas chromatography instrumentation and methodology for the analysis of volatile organic compounds (VOC) from adsorbent sampling devices. Supercritical fluid extraction offers potential a...

  19. TREATMENT OF CHLORINATED VOLATILE ORGANIC COMPOUNDS IN UPFLOW WETLAND MESOCOSMS. (R828773C003)

    EPA Science Inventory

    Sorption, biodegradation and hydraulic parameters were determined in the laboratory for two candidate soil substrate mixtures for construction of an upflow treatment wetland for volatile organic compounds (VOCs) at a Superfund site. The major parent contaminants in the groundw...

  20. DESIGN AND FABRICATION OF A MEMS CHEMICAPACITIVE SENSOR FOR THE DETECTION OF VOLATILE ORGANIC COMPOUNDS

    E-print Network

    Baker, R. Jacob

    DESIGN AND FABRICATION OF A MEMS CHEMICAPACITIVE SENSOR FOR THE DETECTION OF VOLATILE ORGANIC by Todd Jackson Plum entitled Design and Fabrication of a MEMS Chemicapacitive Sensor for the Detection........................................................................... 6 Polymer-Based Chemical Microsensors

  1. Measurements of Volatile Organic Compounds Using Proton Transfer Reaction - Mass Spectrometry during the MILAGRO 2006 Campaign

    E-print Network

    Fortner, E. C.

    Volatile organic compounds (VOCs) were measured by proton transfer reaction – mass spectrometry (PTR-MS) on a rooftop in the urban mixed residential and industrial area North Northeast of downtown Mexico City as part of ...

  2. AUTOMATED CRYOGENIC PRECONCENTRATION AND GAS CHROMATOGRAPHIC DETERMINATION OF VOLATILE ORGANIC COMPOUNDS IN AIR

    EPA Science Inventory

    The performances of two nominally identical automated monitors for quantifying volatile organic compounds were compared on identical ambient laboratory air samples. The monitors incorporate cryogenic preconcentration subunits specially designed for controlled release of liquid ni...

  3. Flux Measurements of Volatile Organic Compounds from an Urban Tower Platform 

    E-print Network

    Park, Chang Hyoun

    2011-08-08

    combined with a dual-channel gas chromatography - flame ionization detection used for volatile organic compound (VOC) flux measurements in the urban area, focusing on the results of selected anthropogenic VOCs, including benzene, toluene, ethylbenzene...

  4. 78 FR 24990 - Approval and Promulgation of Implementation Plans; Ohio; Volatile Organic Compound Emission...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-29

    ...C) Ohio Administrative Code Rule 3745-21-21 ``Storage of volatile organic liquids in fixed roof tanks and external floating roof tanks.'', effective May 12, 2011. (D) Ohio Administrative Code Rule 3745-21-23 ``Control of...

  5. Development of a Cryogen-Free Concentration System for Measurements of Volatile Organic

    E-print Network

    Wingenter, Oliver W.

    Development of a Cryogen-Free Concentration System for Measurements of Volatile Organic Compounds of Chemistry, New Mexico Institute of Mining and Technology, Socorro, New Mexico 87801 An innovative cryogen

  6. VOLATILE ORGANIC COMPOUNDS IN INDOOR AIR: A SURVEY OF VARIOUS STRUCTURES

    EPA Science Inventory

    Co-workers collected indoor air samples in their homes in SUMMA polished canisters. Upon receipt in the laboratory, the whole air samples were analyzed for volatile organic compounds (VOCs) using cryogenic sample preconcentration and subsequent capillary column chromatography. Ea...

  7. Effects of hops (Humulus lupulus L.) extract on volatile fatty acid production by rumen bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aims: To determine the effects of hops extract, on in vitro volatile fatty acid (VFA) production by bovine rumen microorganisms. Methods and Results: When mixed rumen microbes were suspended in media containing carbohydrates, the initial rates of VFA production were suppressed by beta-acid rich hops...

  8. Screening of volatile organic compounds in river sediment

    SciTech Connect

    Kawata, K.; Tanabe, A.; Saito, S. [Niigata Prefectural Research Lab. for Health and Environment (Japan)] [and others] [Niigata Prefectural Research Lab. for Health and Environment (Japan); and others

    1997-06-01

    Volatile organic compounds (VOCs), such as trichloroethene, toluene and xylenes have been reported to be detected from river water and sediment, because a part of VOCs charged into river can be distributed to river sediment. Fifty-three common VOCs in water have been simultaneously determined with good accuracy and precision by gas chromatography - mass spectrometry (GC/MS) with headspace method as well as purge-and-trap method. However, simultaneous determination methods for the VOCs in sediment have not been established. Several GC or GOMS methods have been reported to determine some VOCs in sediment, purge-and-trap, distillation, headspace and solvent extraction. Among them headspace GC/MS method appears to be the most appropriate method for screening the VOCs in sediments, because of its simplicity in analytical procedure. Hewitt et al. have reported that headspace method gave no statistically different results from purge-and-trap method for GC/MS determination of four VOCs in soil. Voice and Kolb have reported that headspace GC method gave better results to determine nine VOCs in soil than purge-and-trap method or solvent extraction method followed by headspace. However, headspace analysis of some VOCs in sediments could give insufficient recoveries. This is because VOCs adsorb to sediment. To improve their low recoveries from sediment, we have previously used a stable isotope-labeled compound as an internal standard to determine eight chlorinated VOCs. However, this method is not proper for determining simultaneously as many as 53 VOCs with various physical properties. Therefore, we investigate headspace GC/MS method with standard addition method for simultaneous screening of them in sediment. In this paper, we describe effects of a few headspace conditions on the VOC recoveries from sediment, and present screening results of the VOCs in sediments from mouths of rivers and a port in Niigata, Japan. 17 refs., 3 figs., 3 tabs.

  9. Online measurements of the emissions of intermediate-volatility and semi-volatile organic compounds from aircraft

    NASA Astrophysics Data System (ADS)

    Cross, E. S.; Hunter, J. F.; Carrasquillo, A. J.; Franklin, J. P.; Herndon, S. C.; Jayne, J. T.; Worsnop, D. R.; Miake-Lye, R. C.; Kroll, J. H.

    2013-08-01

    A detailed understanding of the climate and air quality impacts of aviation requires measurements of the emissions of intermediate-volatility and semi-volatile organic compounds (I/SVOCs) from aircraft. Currently both the amount and chemical composition of aircraft I/SVOC emissions remain poorly characterized. Here we characterize I/SVOC emissions from aircraft, using a novel instrument for the online, quantitative measurement of the mass loading and composition of low-volatility organic vapors. Emissions from the NASA DC8 aircraft were sampled on the ground 143 m downwind of the engines and characterized as a function of engine power from idle (4% maximum rated thrust) through 85% power. Results show that I/SVOC emissions are highest during engine idle operating conditions, with decreasing but non-zero I/SVOC emissions at higher engine powers. Comparison of I/SVOC emissions with total hydrocarbon (THC) measurements, VOC measurements, and an established emissions profile indicates that I/SVOCs comprise 10-20% of the total organic gas-phase emissions at idle, and an increasing fraction of the total gas-phase organic emissions at higher powers. Positive matrix factorization of online mass spectra is used to identify three distinct types of I/SVOC emissions: aliphatic, aromatic and oxygenated. The volatility and chemical composition of the emissions suggest that unburned fuel is the dominant source of I/SVOCs at idle, while pyrolysis products make up an increasing fraction of the I/SVOCs at higher powers. Oxygenated I/SVOC emissions were detected at lower engine powers (?30%) and may be linked to cracked, partially oxidized or unburned fuel components.

  10. Online measurements of the emissions of intermediate-volatility and semi-volatile organic compounds from aircraft

    NASA Astrophysics Data System (ADS)

    Cross, E. S.; Hunter, J. F.; Carrasquillo, A. J.; Franklin, J. P.; Herndon, S. C.; Jayne, J. T.; Worsnop, D. R.; Miake-Lye, R. C.; Kroll, J. H.

    2013-03-01

    A detailed understanding of the climate and air quality impacts of aviation requires detailed measurements of the emissions of intermediate-volatility and semi-volatile organic compounds (I/SVOCs) from aircraft. Currently both the amount and chemical composition of aircraft I/SVOC emissions remain poorly characterized. Here we characterize I/SVOC emissions from aircraft, using a novel instrument for the online, quantitative measurement of the mass loading and composition of low-volatility organic vapors. Emissions from the NASA DC8 aircraft were sampled on the ground, 143 m downwind of the engines and characterized as a function of engine power from ground idle (~4% maximum rated thrust) through 85% power. Results show that I/SVOC emissions are highest during engine-idle operating conditions, with decreasing but non-zero I/SVOC emissions at higher engine powers. Comparison of I/SVOC emissions with total hydrocarbon (THC) measurements, VOC measurements, and an established emissions profile indicates that I/SVOCs comprise 10-20% of the total organic gas phase emissions at idle, and an increasing fraction of the total gas phase organic emissions at higher powers. Positive matrix factorization of online mass spectra is used to identify three distinct types of I/SVOC emissions: aliphatic, aromatic and oxygenated. The volatility and chemical composition of the emissions suggest that unburned fuel is the dominant source of I/SVOCs at idle, while pyrolysis products make up an increasing fraction of the I/SVOCs at higher powers. Oxygenated I/SVOC emissions were detected at lower engine powers (?30%) and may be linked to cracked, partially oxidized or unburned fuel components.

  11. Catalytic combustion of volatile organic compounds on gold\\/cerium oxide catalysts

    Microsoft Academic Search

    Salvatore Scirè; Simona Minicò; Carmelo Crisafulli; Cristina Satriano; Alessandro Pistone

    2003-01-01

    Catalytic combustion of some representative volatile organic compounds (VOCs) (2-propanol, methanol and toluene) was investigated on gold\\/cerium oxide catalysts prepared by coprecipitation (CP) and deposition–precipitation (DP). The presence of gold has been found to enhance the activity of cerium oxide towards the oxidation of the selected volatile organic compounds, the extent of this effect depending on the preparation method of

  12. Volatile organic compound emissions from usaf wastewater treatment plants in ozone nonattainment areas. Master's thesis

    Microsoft Academic Search

    Ouellette

    1994-01-01

    In accordance with the 1990 Clean Air Act Amendments (CAAA), this research conducts an evaluation of the potential emission of volatile organic compounds (VOCs) from selected Air Force wastewater treatment plants. Using a conservative mass balance analysis and process specific simulation models, volatile organic emission estimates are calculated for four individual facilities--Edwards AFB, Luke AFB, McGuire AFB, and McClellan AFB--which

  13. Volatile fatty acids production from food wastes and its application to biological nutrient removal

    Microsoft Academic Search

    S.-J. Lim; D. W. Choi; W. G. Lee; S. Kwon; H. N. Chang

    2000-01-01

    Korean food wastes were anaerobically digested to produce volatile fatty acids (VFA) that can be used as a carbon source in biological nutrient removal in a sequential batch reactor (SBR). Acetate, propionate and butyrate were produced at a yield of 379-400 g VFA\\/kg VS0 (initial volatile solids). The ratio of SCOD (Soluble Chemical Oxygen Demand) of VFA to ammonia nitrogen

  14. Global simulation of aromatic volatile organic compounds in the atmosphere

    NASA Astrophysics Data System (ADS)

    Cabrera Perez, David; Taraborrelli, Domenico; Pozzer, Andrea

    2015-04-01

    Among the large number of chemical compounds in the atmosphere, the organic group plays a key role in the tropospheric chemistry. Specifically the subgroup called aromatics is of great interest. Aromatics are the predominant trace gases in urban areas due to high emissions, primarily by vehicle exhausts and fuel evaporation. They are also present in areas where biofuel is used (i.e residential wood burning). Emissions of aromatic compounds are a substantial fraction of the total emissions of the volatile organic compounds (VOC). Impact of aromatics on human health is very important, as they do not only contribute to the ozone formation in the urban environment, but they are also highly toxic themselves, especially in the case of benzene which is able to trigger a range of illness under long exposure, and of nitro-phenols which cause detrimental for humans and vegetation even at very low concentrations. The aim of this work is to assess the atmospheric impacts of aromatic compounds on the global scale. The main goals are: lifetime and budget estimation, mixing ratios distribution, net effect on ozone production and OH loss for the most emitted aromatic compounds (benzene, toluene, xylenes, ethylbenzene, styrene and trimethylbenzenes). For this purpose, we use the numerical chemistry and climate simulation ECHAM/MESSy Atmospheric Chemistry (EMAC) model to build the global atmospheric budget for the most emitted and predominant aromatic compounds in the atmosphere. A set of emissions was prepared in order to include biomass burning, vegetation and anthropogenic sources of aromatics into the model. A chemical mechanism based on the Master Chemical Mechanism (MCM) was developed to describe the chemical oxidation in the gas phase of these aromatic compounds. MCM have been reduced in terms of number of chemical equation and species in order to make it affordable in a 3D model. Additionally other features have been added, for instance the production of HONO via ortho-nitrophenols photolysis. The model results are compared with observations from different surface and aircraft campaigns in order to estimate the accuracy of the model.

  15. Semi-volatile secondary organic aerosol in urban atmospheres: meeting a measurement challenge

    NASA Astrophysics Data System (ADS)

    Eatough, Delbert J.; Long, Russell W.; Modey, William K.; Eatough, Norman L.

    Ammonium nitrate and semi-volatile organic compounds are significant components of fine particles in urban atmospheres. These components, however, are not properly determined with current US EPA accepted methods such as the PM 2.5 FRM or other single filter samplers due to significant losses of semi-volatile material (SVM) from particles collected on the filter during sampling. Continuous PM 2.5 mass measurements are attempted using methods such as the R&P TEOM monitor. This method, however, heats the sample to remove particle-bound water which also results in evaporation of SVM. Research at Brigham Young University has resulted in samplers for both the integrated and continuous measurement of total PM 2.5, including the SVM. The PC-BOSS is a charcoal diffusion denuder based sampler for the determination of fine particulate chemical composition including the semi-volatile organic material. The RAMS is a modified TEOM monitor which includes diffusion denuders and Nafion dryers to remove gas phase material which can be absorbed by a charcoal sorbent filter. The RAMS then uses a "sandwich filter" consisting of a conventional particle collecting Teflon coated TX40 filter, followed by an activated charcoal sorbent filter which retains any semi-volatile ammonium nitrate or organic material lost from the particles collected on the TEOM monitor Teflon coated filter, thus allowing for determination of total PM 2.5 mass including the SVM. Recent research conducted by Brigham Young University using these two samplers has indicated the following about semi-volatile organic aerosol: The majority of semi-volatile fine particulate organic material is secondary organic aerosol. This semi-volatile organic aerosol is not retained on the heated filter of a regular TEOM monitor and hence is not measured by this sampling technique. In addition, secondary ammonium nitrate is also lost. Much of the semi-volatile organic aerosol is also lost during sampling from single filter samplers such as the PM 2.5 FRM sampler. The amount of semi-volatile organic aerosol lost from single filter samplers can vary from less than 1/3 that lost from heated TEOM filters during cold winter conditions to essentially all during warm summer conditions. Semi-volatile organic aerosol can only be reliably collected using an appropriate denuder sampler. Either a PM 2.5 FRM sampler or the IMPROVE sampler can be easily modified to a denuder sampler with filters which can be analyzed for semi-volatile OC, nonvolatile OC and EC using existing OC/EC analytical techniques. The research upon which these statements are based is summarized in this document.

  16. Modelling the volatile and organic content of Enceladus' ocean

    NASA Astrophysics Data System (ADS)

    Sotin, Christophe; Lunine, Jonathan

    2015-04-01

    A variety of Cassini data on Enceladus suggest that the jets of material spraying out of the south polar region of this Saturnian moon are connected to a regional or global ocean below an icy crust -- an ocean in contact with a rocky core [1, 2, 3]. In this study we construct models of the mineralogical and elemental composition of Enceladus' rocky core so as to predict the abundance of species that may provide more detail on the extent of hydrothermal evolution of the ocean and its interaction with the rocky core. Using equations of state of the relevant material, the models are made consistent with the values of the gravity coefficients [1]. We investigate the amount of organic molecules (amino acids and fatty acids) as well as the amount of 40Ar that could be present in Enceladus' deep ocean and, therefore, in the icy grains expelled into space. Some models show that the conditions in Enceladus rocky core can be very similar to those existing in the Earth's oceanic crust, suggesting that all of Enceladus rocky core would have been leached over the age of the solar system. The amount of 40Ar dissolved in the ocean provides constraints on the amount of K in the building blocks of Enceladus, the amount of leaching of the silicate fraction, and the extent of the ocean. Based on chondritic abundances for K, we have calculated that the total potential of 40Ar is about 5.6x1012 kg. We also investigate the amount of organic material that would have been concentrated in the ocean. The Murchison meteorite contains about 60 ppm of amino acids, mainly glycine [4]. Assuming that all the rocky core has been leached by water, the modelled concentration of amino acids exceeds 150 ppm. Carboxylic acids were detected in the Asuka carbonaceous chondrites in Antarctica with values, for example, of 90 nmol/g of benzoic acid. Assuming this value, about 35 ppm of benzoic acid would be present in Enceladus' ocean. The concentrations are larger if the ocean is not global, but rather limited to the South Pole [1], and assuming that all the leached material is concentrated in the regional ocean (and not partially trapped elsewhere in ice). A future mission to Enceladus could eventually measure these quantities in order to assess the extent of evolution of Enceladus, and the potential presence of the building blocks of life in its ocean. This work has been performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract to NASA. [1] Iess L. et al. (2014) Science, 344, 78. [2] Porco C. et al. (2014) The Astronomical Journal, 148:45. [3] Hedman M. M. et al. (2013) Nature, 500, 182-184. [4] Sephton M.A. (2002) Nat. Prod. Rep., 19, 292-311.

  17. A Push-Pull Test to Measure Volatilization Fluxes of Organic Pollutants without Flux Chambers

    NASA Astrophysics Data System (ADS)

    Reid, M. C.; Jaffe, P. R.

    2011-12-01

    Volatilization of organic contaminants is a potentially significant removal mechanism from wetlands, but field measurements are scarce and the physiochemical controls on volatilization from wetland soils remain poorly understood. It has been established that volatilization rates of certain pollutants are enhanced by vegetation and are strongly correlated with evapotranspiration (ET). These observations rely on flux chambers measurements, which are characterized by significant uncertainty due the chamber's effects on the meteorological variables around the plant and consequent impact on the biophysical processes governing ET and plant uptake of soil contaminants. Here we present data from a mesocosm study using a modified single-well push-pull test to measure in-situ volatilization rates from inundated soils vegetated with the wetland macrophytes Scirpus acutus and Typha latifolia, as well as from unplanted soil. This new method uses a test solution containing the volatile tracers sulfur hexafluoride (SF6), helium (He), and dichlorodifluoromethane (CFC-12) to estimate first-order volatilization rates and examine the relationship between physiochemical properties and volatilization rates. The test also yields an estimate for the volume of subsurface gas bubbles, which is used to derive a retardation factor for the effect of interphase partitioning on the estimation of kinetic parameters. We evaluate models to partition observed fluxes into different pathways for plant-mediated volatilization: transpirational uptake and consequent volatilization, and gas-phase diffusion through porous root aerenchyma. Those models are then used to scale tracer-derived volatilization fluxes to priority organic pollutants including benzene, trichloroethylene, and vinyl chloride. We also discuss the implementation of this method at field scales to estimate volatilization as a component of phytoremediation applications.

  18. Challenges in quantitative analyses for volatile organic compounds bound to lipocalins.

    PubMed

    Kwak, Jae

    2012-11-01

    In this communication, I describe the challenges in quantitative analyses for volatile organic compounds in mouse urine, which are primarily caused by the presence of the major urinary proteins, a lipocalin subfamily, that sequester volatile ligands. The analyses of volatile compounds in mouse urine have been performed since the late 1970s. However, none of them considered the binding interactions of the quantified compounds with the urinary proteins. Some volatile ligands are tightly bound to the proteins and may not be extracted completely by organic solvents. The amounts of volatile ligands measured by external standard calibration represent those of the unbound ligands in the headspace, not the total amounts in urine. Addition of internal standards displaces ligands bound to the proteins, resulting in a completely different volatile profile. Normalization of volatile compounds using relative peak area (or height) ratios may not be used in the conditions where displacement of ligands bound to the proteins occurs. Because of the unique chemical properties of mouse urine, I have not been able to find a good quantification method for the volatile compounds released from mouse urine. I hope that the identification of these issues will stimulate others to come up with novel approaches. PMID:22965638

  19. Mass spectra deconvolution of low, medium, and high volatility biogenic secondary organic aerosol.

    PubMed

    Kostenidou, Evangelia; Lee, Byong-Hyoek; Engelhart, Gabriella J; Pierce, Jeffrey R; Pandis, Spyros N

    2009-07-01

    Secondary organic aerosol (SOA) consists of compounds with a wide range of volatilities and its ambient concentration is sensitive to this volatility distribution. Recent field studies have shown that the typical mass spectrum of ambient oxygenated organic aerosol (OOA) as measured by the Aerodyne Aerosol Mass Spectrometer (AMS) is quite different from the SOA mass spectra reported in smog chamber experiments. Part of this discrepancy is due to the dependence of SOA composition on the organic aerosol concentration. High precursor concentrations lead to higher concentrations of the more volatile species in the produced SOA while at lower concentrations the less volatile compounds dominate the SOA composition. alpha-Pinene, beta-pinene, d-limonene, and beta-caryophyllene ozonolysis experiments were performed at moderate concentration levels. Using a thermodenuder the more volatile SOA species were removed achieving even lower SOA concentration. The less volatile fraction was then chemically characterized by an AMS. The signal fraction of m/z44, and thus the concentration of C02+, is significantly higher for the less volatile SOA. High NO(x) conditions result in less oxidized SOA than low NO(x) conditions, while increasing relative humidity levels results in more oxidized products for limonene but has little effect on alpha-and beta-pinene SOA. Combining a smog chamber with a thermodenuder model employing the volatility basis-set framework, the AMS SOA mass spectrum for each experiment and for each precursor is deconvoluted into low, medium, and high volatility component mass spectra. The spectrum of the surrogate component with the lower volatility is quite similar to that of ambient OOA. PMID:19673280

  20. Separation of Boric Acid from PWR Waste by Volatilization During Evaporation

    Microsoft Academic Search

    A. Bruggeman; J. Braet; F. Smaers; P. De Regge

    1997-01-01

    SCK·CEN has developed a process to separate boric acid during and\\/or after evaporation of the liquid waste from pressurized light-water reactors. The key goal is to achieve higher waste volume reduction factors, while maintaining low activity discharge limits. An additional goal is to obtain purified boric acid for recycling. The process is based on the volatility of boric acid in

  1. Volatile Organic Compound Investigation Results, 300 Area, Hanford Site, Washington

    SciTech Connect

    Peterson, Robert E.; Williams, Bruce A.; Smith, Ronald M.

    2008-07-07

    Unexpectedly high concentrations of volatile organic compounds (VOC) were discovered while drilling in the unconfined aquifer beneath the Hanford Site’s 300 Area during 2006. The discovery involved an interval of relatively finer-grained sediment within the unconfined aquifer, an interval that is not sampled by routine groundwater monitoring. Although VOC contamination in the unconfined aquifer has been identified and monitored, the concentrations of newly discovered contamination are much higher than encountered previously, with some new results significantly higher than the drinking water standards. The primary contaminant is trichloroethene, with lesser amounts of tetrachloroethene. Both chemicals were used extensively as degreasing agents during the fuels fabrication process. A biological degradation product of these chemicals, 1,2-dichloroethene, was also detected. To further define the nature and extent of this contamination, additional characterization drilling was undertaken during 2007. Four locations were drilled to supplement the information obtained at four locations drilled during the earlier investigation in 2006. The results of the combined drilling indicate that the newly discovered contamination is limited to a relatively finer-grained interval of Ringold Formation sediment within the unconfined aquifer. The extent of this contamination appears to be the area immediately east and south of the former South Process Pond. Samples collected from the finer-grained sediment at locations along the shoreline confirm the presence of the contamination near the groundwater/river interface. Contamination was not detected in river water that flows over the area where the river channel potentially incises the finer-grained interval of aquifer sediment. The source for this contamination is not readily apparent. A search of historical documents and the Hanford Waste Information Data System did not provide definitive clues as to waste disposal operations and/or spills that might have resulted in groundwater contamination in this sediment, although several relatively small accidental releases of VOCs have occurred in the past in the northern portion of the 300 Area. It is likely that large quantities of degreasing solutions were disposed to the North and South Process Ponds during the 1950s and 1960s, and that evidence for them in the upper portion of the unconfined aquifer has been removed because of groundwater movement through the much more transmissive sediment. Also, investigations to date have revealed no evidence to suggest that a dense, non-aqueous phase liquid remains undetected in the subsurface. Potential pathways for contamination to migrate from this finer-grained sediment include groundwater movement through the interval to offshore locations in the Columbia River channel, dispersion out of the finer-grained interval into the overlying transmissive sediment (again, with transport to the riverbed), and potential future withdrawal via water supply wells.

  2. Geographical traceability of Italian white truffle (Tuber magnatum Pico) by the analysis of volatile organic compounds.

    PubMed

    Gioacchini, Anna Maria; Menotta, Michele; Guescini, Michele; Saltarelli, Roberta; Ceccaroli, Paola; Amicucci, Antonella; Barbieri, Elena; Giomaro, Giovanna; Stocchi, Vilberto

    2008-10-01

    Results are presented that were obtained on the geographic traceability of the white truffle Tuber magnatum Pico. Solid-phase microextraction coupled to gas chromatography/mass spectrometry (SPME-GC/MS) was employed to characterize the volatile profile of T. magnatum white truffle produced in seven geographical areas of Italy. The main components of the volatile fraction were identified using SPME-GC/MS. Significant differences in the proportion of volatile constituents from truffles of different geographical areas were detected. The results suggest that, besides genetic factors, environmental conditions influence the formation of volatile organic compounds. The mass spectra of the volatile fraction of the samples were used as fingerprints to characterize the geographical origin. Next, stepwise factorial discriminant analysis afforded a limited number of characteristic fragment ions that allowed a geographical classification of the truffles studied. PMID:18798200

  3. The effect of fumaric acid and sodium fumarate supplementation to diets for weanling pigs on amino acid digestibility and volatile fatty acid concentrations in ileal digesta

    Microsoft Academic Search

    V. M. Gabert; W. C. Sauer

    1995-01-01

    An experiment was carried out with 12 Camborough × Canabrid barrows to determine the effect of fumaric acid (FA) and sodium fumarate (NaFA) supplementation of the diet on the apparent ileal digestibility coefficients of amino acids and the concentrations of volatile fatty acids in ileal digesta. The pigs were weaned at 28 days of age (initial and final body weights

  4. [Opportunities for volatile fatty acids using in early diagnostics of infected pancreonecrosis].

    PubMed

    Gagua, A K; Ivanenkov, I M; Vorob'ev, P Iu

    2014-01-01

    It was analyzed the treatment results of 108 patients with pancreonecrosis (PN). Gas-liquid chromatography with definition of blood concentration of volatile fatty acids (VFA) was used additionally for timely diagnostics of infected pancreonecrosis. Volatile fatty acids are toxic metabolites of microorganisms. Statistically significant threshold values of VFA were revealed. These values allow to diagnose timely early phase of PN infection and the nature of the microflora. It was defined changes of VFA depending on the severity of infectious process in pancreas and retroperitoneal fiber. PMID:25589178

  5. 40 CFR 60.712 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Magnetic Tape Coating Facilities § 60.712 Standards for volatile...of a new VOC control device (other than a condenser) on a magnetic tape coating operation shall control emissions from the...

  6. 40 CFR 60.712 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Magnetic Tape Coating Facilities § 60.712 Standards for volatile...of a new VOC control device (other than a condenser) on a magnetic tape coating operation shall control emissions from the...

  7. 40 CFR 60.722 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Coating of Plastic Parts for Business Machines § 60.722 Standards for volatile...coating of plastic parts for business machines. (2) 1.5 kilograms of VOC's...coating of plastic parts for business machines. (3) 2.3 kilograms of...

  8. 40 CFR 60.722 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Coating of Plastic Parts for Business Machines § 60.722 Standards for volatile...coating of plastic parts for business machines. (2) 1.5 kilograms of VOC's...coating of plastic parts for business machines. (3) 2.3 kilograms of...

  9. Detection of Volatile Organic Compounds by Weight-Detectable Sensors coated with Metal-Organic Frameworks

    NASA Astrophysics Data System (ADS)

    Yamagiwa, Hiroki; Sato, Seiko; Fukawa, Tadashi; Ikehara, Tsuyoshi; Maeda, Ryutaro; Mihara, Takashi; Kimura, Mutsumi

    2014-09-01

    Detection of volatile organic compounds (VOCs) using weight-detectable quartz microbalance and silicon-based microcantilever sensors coated with crystalline metal-organic framework (MOF) thin films is described in this paper. The thin films of two MOFs were grown from COOH-terminated self-assembled monolayers onto the gold electrodes of sensor platforms. The MOF layers worked as the effective concentrators of VOC gases, and the adsorption/desorption processes of the VOCs could be monitored by the frequency changes of weight-detectable sensors. Moreover, the MOF layers provided VOC sensing selectivity to the weight-detectable sensors through the size-selective adsorption of the VOCs within the regulated nanospace of the MOFs.

  10. Detection of Volatile Organic Compounds by Weight-Detectable Sensors coated with Metal-Organic Frameworks

    PubMed Central

    Yamagiwa, Hiroki; Sato, Seiko; Fukawa, Tadashi; Ikehara, Tsuyoshi; Maeda, Ryutaro; Mihara, Takashi; Kimura, Mutsumi

    2014-01-01

    Detection of volatile organic compounds (VOCs) using weight-detectable quartz microbalance and silicon-based microcantilever sensors coated with crystalline metal-organic framework (MOF) thin films is described in this paper. The thin films of two MOFs were grown from COOH-terminated self-assembled monolayers onto the gold electrodes of sensor platforms. The MOF layers worked as the effective concentrators of VOC gases, and the adsorption/desorption processes of the VOCs could be monitored by the frequency changes of weight-detectable sensors. Moreover, the MOF layers provided VOC sensing selectivity to the weight-detectable sensors through the size-selective adsorption of the VOCs within the regulated nanospace of the MOFs. PMID:25175808

  11. Online monitoring of concentration and dynamics of volatile fatty acids in anaerobic digestion processes with mid-infrared spectroscopy.

    PubMed

    Falk, Harry Michael; Reichling, Peter; Andersen, Christian; Benz, Roland

    2015-02-01

    An ATR-MIR-FTIR spectrometer was integrated into a laboratory scale anaerobic digestion setup. Automatically, a sludge sample from the digester was transferred to a measurement cell; an IR spectrum was recorded and evaluated by chemometric models to estimate the concentration of the individual volatile fatty acids (VFA). The calibration set included semi-artificial samples spiked with known concentrations of the VFA as well as original samples from a continuous fermentation. High-performance liquid chromatography (HPLC) was used as a reference analysis of the samples. The models were optimized for a low root mean square error of prediction (RMSEP). R(2) for acetic acid, propionic acid, isobutyric acid, butyric acid, valeric acid, and isovaleric acid were 0.94, 0.88, 0.83, 0.75, 0.59, and 0.90, respectively. The accuracy of the models was validated in a second experiment. Considering the complex and heterogeneous sludge composition and the chemical similarity of VFA, absolute concentration and dynamic (increasing and decreasing concentration of VFA) was predicted well for acetic, propionic, isobutyric, and isovaleric acid (in their respective concentration range); Butyric acid could not be detected. The installed setup was able to gather and measure native samples from the digester (every 2 h) automatically over a period of 6 months without problems of clogging or biofouling. The instant and continuous analysis of the concentration of the VFA made it possible to evaluate the current bioprocess status and adjust the organic loading rate accordingly. PMID:25142153

  12. Determination of volatile organic compounds at the parts per trillion level in complex aqueous matrices using membrane introduction mass spectrometry

    SciTech Connect

    Bauer, S. (MIMS Technology Development Incorporated, West Lafayette, IN (United States)); Solyom, D. (Purdue Univ., West Lafayette, IN (United States))

    1994-12-15

    Recent advances in membrane introduction mass spectrometry (MIMS) have demonstrated the utility of MIMS in the trace level analysis of volatile organic compounds in water. The present study details the performance of an ion trap mass spectrometer fitted with a capillary membrane probe in the direct analysis of volatile organic compounds in water using flow injection techniques. Detection limits for 59 volatile organic compounds listed in EPA method 524.2 were determined to be in the mid to low parts per trillion (pptr) range using MIMS. Analyses of these compounds in untreated river water, sea water, and matrices containing strong acids and bases are demonstrated. The matrix studies show that there are no adverse effects on compound identification or detection limits resulting from matrix interferences in MIMS. Further experiments demonstrate the utility of MIMS as a direct analysis technique for on-line monitoring of trihalomethane formation in water treatment facilities. Detection limits of 100 pptr were obtained for the four trihalomethanes, with repetitive sample times averaging 6 min/sample. Quantitation of the total trihalomethane content was performed in one step, demonstrating further increases in analytical speed over traditional analysis methods. 26 refs., 9 figs., 2 tabs.

  13. Systemic Resistance Induced by Volatile Organic Compounds Emitted by Plant Growth-Promoting Fungi in Arabidopsis thaliana

    PubMed Central

    Naznin, Hushna Ara; Kiyohara, Daigo; Kimura, Minako; Miyazawa, Mitsuo; Shimizu, Masafumi; Hyakumachi, Mitsuro

    2014-01-01

    Volatile organic compounds (VOC) were extracted and identified from plant growth-promoting fungi (PGPF), Phoma sp., Cladosporium sp. and Ampelomyces sp., using gas chromatography–mass spectrometry (GC-MS). Among the three VOC extracted, two VOC blends (emitted from Ampelomyces sp. and Cladosporium sp.) significantly reduced disease severity in Arabidopsis plants against Pseudomonas syringae pv. tomato DC3000 (Pst). Subsequently, m-cresol and methyl benzoate (MeBA) were identified as major active volatile compounds from Ampelomyces sp. and Cladosporium sp., respectively, and found to elicit induced systemic resistance (ISR) against the pathogen. Molecular signaling for disease suppression by the VOC were investigated by treating different mutants and transgenic Arabidopsis plants impaired in salicylic acid (SA) or Jasmonic acid (JA)/ethylene (ET) signaling pathways with m-cresol and MeBA followed by challenge inoculation with Pst. Results show that the level of protection was significantly lower when JA/ET-impaired mutants were treated with MeBA, and in SA-, and JA/ET-disrupted mutants after m-cresol treatment, indicating the involvement of these signal transduction pathways in the ISR primed by the volatiles. Analysis of defense-related genes by real-time qRT-PCR showed that both the SA-and JA-signaling pathways combine in the m-cresol signaling of ISR, whereas MeBA is mainly involved in the JA-signaling pathway with partial recruitment of SA-signals. The ET-signaling pathway was not employed in ISR by the volatiles. Therefore, this study identified two novel volatile components capable of eliciting ISR that may be promising candidates in biological control strategy to protect plants from diseases. PMID:24475190

  14. Systemic resistance induced by volatile organic compounds emitted by plant growth-promoting fungi in Arabidopsis thaliana.

    PubMed

    Naznin, Hushna Ara; Kiyohara, Daigo; Kimura, Minako; Miyazawa, Mitsuo; Shimizu, Masafumi; Hyakumachi, Mitsuro

    2014-01-01

    Volatile organic compounds (VOC) were extracted and identified from plant growth-promoting fungi (PGPF), Phoma sp., Cladosporium sp. and Ampelomyces sp., using gas chromatography-mass spectrometry (GC-MS). Among the three VOC extracted, two VOC blends (emitted from Ampelomyces sp. and Cladosporium sp.) significantly reduced disease severity in Arabidopsis plants against Pseudomonas syringae pv. tomato DC3000 (Pst). Subsequently, m-cresol and methyl benzoate (MeBA) were identified as major active volatile compounds from Ampelomyces sp. and Cladosporium sp., respectively, and found to elicit induced systemic resistance (ISR) against the pathogen. Molecular signaling for disease suppression by the VOC were investigated by treating different mutants and transgenic Arabidopsis plants impaired in salicylic acid (SA) or Jasmonic acid (JA)/ethylene (ET) signaling pathways with m-cresol and MeBA followed by challenge inoculation with Pst. Results show that the level of protection was significantly lower when JA/ET-impaired mutants were treated with MeBA, and in SA-, and JA/ET-disrupted mutants after m-cresol treatment, indicating the involvement of these signal transduction pathways in the ISR primed by the volatiles. Analysis of defense-related genes by real-time qRT-PCR showed that both the SA-and JA-signaling pathways combine in the m-cresol signaling of ISR, whereas MeBA is mainly involved in the JA-signaling pathway with partial recruitment of SA-signals. The ET-signaling pathway was not employed in ISR by the volatiles. Therefore, this study identified two novel volatile components capable of eliciting ISR that may be promising candidates in biological control strategy to protect plants from diseases. PMID:24475190

  15. A volatile organics concentrator for use in monitoring Space Station water quality

    NASA Technical Reports Server (NTRS)

    Ehntholt, Daniel J.; Bodek, Itamar; Valentine, James R.; Trabanino, Rudy; Vincze, Johanna E.; Sauer, Richard L.

    1990-01-01

    The process used to identify, select, and design an approach to the isolation and concentration of volatile organic compounds from a water sample prior to chemical analysis in a microgravity environment is discerned. The trade analysis leading to the recommended volatile organics concentrator (VOC) concept to be tested in a breadboard device is presented. The system covers the areas of gases, volatile separation from water, and water removal/gas chromatograph/mass spectrometer interface. Five options for potential use in the VOC and GC/MS system are identified and ranked, and also nine options are presented for separation of volatiles from the water phase. Seven options for use in the water removal/GC column and MS interface are also identified and included in the overall considerations. A final overall recommendation for breadboard VOC testing is given.

  16. The development 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.; Valentine, James R.; Trabanino, Rudy; Webb, Johanna V.; Sauer, Richard L.

    1991-01-01

    A breadboard concept of a volatile organics concentrator (VOC) is manufactured and tested for optimized water-quality analysis in a space environment. The VOC system is attached to a gas chromatograph/mass spectrometer to analyze the volatile chemicals relevant to the operation of Space Station Freedom. The preliminary tests include: (1) comparisons with analyses based on direct on-column injections of standards; (2) analyses of iodinated volatile organics; (3) comparisons of nitrogen vs helium as the chromatography carrier gas; and (4) measurements of collection efficiency. The VOC can analyze EPA method-624 analytes at comparable detection using flame-ionization detection and can analyze volatile iodinated compounds. The breadboard has good reproducibility and can use nitrogen as a carrier gas; good results are noted for the collection and concentration levels and for water removal.

  17. 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.

  18. Bioelectrochemical recovery of waste-derived volatile fatty acids and production of hydrogen and alkali.

    PubMed

    Zhang, Yifeng; Angelidaki, Irini

    2015-09-15

    Volatile fatty acids (VFA) are organic compounds of great importance for various industries and environmental processes. Fermentation and anaerobic digestion of organic wastes are promising alternative technologies for VFA production. However, one of the major challenges is development of sustainable downstream technologies for VFA recovery. In this study, an innovative microbial bipolar electrodialysis cell (MBEDC) was developed to meet the challenge of waste-derived VFA recovery, produce hydrogen and alkali, and potentially treat wastewater. The MBEDC was operated in fed-batch mode. At an applied voltage of 1.2 V, a VFA recovery efficiency of 98.3%, H2 of 18.4 mL and alkali production presented as pH of 12.64 were obtained using synthetic fermentation broth. The applied voltage, initial VFA concentrations and composition were affecting the VFA recovery. The energy balance revealed that net energy (5.20-6.86 kWh/kg-VFA recovered) was produced at all the applied voltages (0.8-1.4 V). The coexistence of other anionic species had no negative effect on VFA transportation. The VFA concentration was increased 2.96 times after three consecutive batches. Furthermore, the applicability of MBEDC was successfully verified with digestate. These results demonstrate for the first time the possibility of a new method for waste-derived VFA recovery and valuable products production that uses wastewater as fuel and bacteria as catalyst. PMID:26057718

  19. Volatility dependence of Henry's law constants of condensable organics: Application to estimate depositional loss of secondary organic aerosols

    NASA Astrophysics Data System (ADS)

    Hodzic, A.; Aumont, B.; Knote, C.; Lee-Taylor, J.; Madronich, S.; Tyndall, G.

    2014-07-01

    The water solubility of oxidation intermediates of volatile organic compounds that can condense to form secondary organic aerosol (SOA) is largely unconstrained in current chemistry-climate models. We apply the Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere to calculate Henry's law constants for these intermediate species. Results show a strong negative correlation between Henry's law constants and saturation vapor pressures. Details depend on precursor species, extent of photochemical processing, and NOx levels. Henry's law constants as a function of volatility are made available over a wide range of vapor pressures for use in 3-D models. In an application using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) over the U.S. in summer, we find that dry (and wet) deposition of condensable organic vapors leads to major reductions in SOA, decreasing surface concentrations by ~50% (10%) for biogenic and ~40% (6%) for short chain anthropogenic precursors under the considered volatility conditions.

  20. Field detection of volatile organic vapors from soil and water matrices

    SciTech Connect

    Goldsmith, J.G.; Taylor, F.G. Jr.

    1990-07-01

    The collection of subsurface soil or sediment samples in survey or screening studies for subsequent volatile organic analysis in the laboratory introduces many considerations including the number of samples to be collected along a depth profile, which subsample to submit, and what treatment and preservation are ideal before sample analysis. Ideally, the sample with the greatest probability for confirming a leaking tank or a spill site would reduce project costs considerably. Using a field compatible photoionization detector, a series of studies using xylene, benzene, and trichloroethylene contaminated soils or water placed in small chambers under temperature control were conducted to simulate field situations. The water contamination study was designed to mimic sampling well headspace for the presence of volatile organic compounds. The results have provided a basis for field screening and sample selection for soils containing volatile organic contaminants and identified some important considerations for screening well headspaces for organic contamination. 4 refs., 7 figs., 4 tabs.

  1. Characterisation of calamansi (Citrus microcarpa). Part I: volatiles, aromatic profiles and phenolic acids in the peel.

    PubMed

    Cheong, Mun Wai; Chong, Zhi Soon; Liu, Shao Quan; Zhou, Weibiao; Curran, Philip; Bin Yu

    2012-09-15

    Volatile compounds in the peel of calamansi (Citrus microcarpa) from Malaysia, the Philippines and Vietnam were extracted with dichloromethane and hexane, and then analysed by gas chromatography-mass spectroscopy/flame ionisation detector. Seventy-nine compounds representing >98% of the volatiles were identified. Across the three geographical sources, a relatively small proportion of potent oxygenated compounds was significantly different, exemplified by the highest amount of methyl N-methylanthranilate in Malaysian calamansi peel. Principal component analysis and canonical discriminant analysis were applied to interpret the complex volatile compounds in the calamansi peel extracts, and to verify the discrimination among the different origins. In addition, four common hydroxycinnamic acids (caffeic, p-coumaric, ferulic and sinapic acids) were determined in the methanolic extracts of calamansi peel using ultra-fast liquid chromatography coupled to photodiode array detector. The Philippines calamansi peel contained the highest amount of total phenolic acids. In addition, p-Coumaric acid was the dominant free phenolic acids, whereas ferulic acid was the main bound phenolic acid. PMID:23107679

  2. A Standardized Sampling Procedure for the Determination of Volatile Organic Compounds (VOC) Determined in Snow Samples

    NASA Astrophysics Data System (ADS)

    Kos, G.; Ariya, P. A.

    2005-12-01

    Snow samples were collected from different semi-remote and urban environments using a standardized sampling procedure in order to minimize sampling errors. Samples were collected in pre-cleaned amber glass and sterile HDPE containers. Glass bottles and all non-sterilized equipment were washed with low nutrient detergent, acid washed and rinsed with ultra-pure water. Samples were collected using pre-sterilized or acid-washed sampling tools and blanks, consisting of ultra-pure water, which were treated identically to the collected samples in to monitor contamination from sampling equipment and the different types of containers. Analysis for VOC was carried out with a previously described, but modified solid phase micro-extraction (SPME) pre-concentration method and determination of compounds using gas-chromatography with mass spectrometric detection (GC-MS) (1). Low concentrations required the use of larger sample volumes and splitless injection mode. Samples analyzed were collected in and around Montreal, Quebec (45.28 N/73.45 W) at Mont-Saint Hilaire (altitude: 415 m a.s.l.), Downtown Montreal and Parc Tremblant. We will present and compare results from all sites, and the implication for atmospheric processes will be discussed. References (1) Kos G, Ariya PA (2004), Determination of Volatile Organic Compounds in Snow Using Solid Phase Micro Extraction, Eos Trans. AGU, 85 (47), Fall Meet. Suppl., Abstract A11B-53

  3. LABORATORY AND FIELD EVALUATION OF THE SEMI-VOST (SEMI-VOLATILE ORGANIC SAMPLING TRAIN) METHOD

    EPA Science Inventory

    Laboratory studies and a second field evaluation have been completed to assess the performance of the Semi-Volatile Organic Sampling Train (Semi-VOST) method for measuring concentrations of principal organic hazardous constituents (POHCs) with boiling points greater than 100 deg ...

  4. The dynamic adsorption behaviour of volatile organic compounds on activated carbon honeycomb monoliths

    Microsoft Academic Search

    M. Yates; J. Blanco; M. A. Martín-Luengo

    2002-01-01

    Adsorption offers an efficient technology for removing volatile organic compounds (VOCs) from air pollution sources. Often activated carbons (ACs) are employed owing to their large specific surface areas, high micropore volumes, rapid adsorption capabilities and selectivity towards organic molecules compared to water vapour or air. However, when large volumes of gas have to be treated pressure drop limitations may arise

  5. Emissions of Biogenic Volatile Organic Compounds and Observations of VOC Oxidation at Harvard Forest

    Microsoft Academic Search

    K. A. McKinney; T. Pho; A. Vasta; B. H. Lee

    2009-01-01

    The contribution of biogenic volatile organic compounds (BVOCs) to oxidant concentrations and secondary organic aerosol (SOA) production in forested environments depends on the emission rates of these compounds. Recent findings have suggested that the emission rates of BVOCs and the range of species emitted could be larger than previously thought. In this study, Proton Transfer Reaction Mass Spectrometry (PTR-MS) was

  6. Modeling organic aerosols in a megacity: potential contribution of semi-volatile and intermediate volatility primary organic compounds to secondary organic aerosol formation

    NASA Astrophysics Data System (ADS)

    Hodzic, A.; Jimenez, J. L.; Madronich, S.; Canagaratna, M. R.; Decarlo, P. F.; Kleinman, L.; Fast, J.

    2010-06-01

    It has been established that observed local and regional levels of secondary organic aerosols (SOA) in polluted areas cannot be explained by the oxidation and partitioning of anthropogenic and biogenic VOC precursors, at least using current mechanisms and parameterizations. In this study, the 3-D regional air quality model CHIMERE is applied to estimate the potential contribution to SOA formation of recently identified semi-volatile and intermediate volatility organic precursors (S/IVOC) in and around Mexico City for the MILAGRO field experiment during March 2006. The model has been updated to include explicitly the volatility distribution of primary organic aerosols (POA), their gas-particle partitioning and the gas-phase oxidation of the vapors. Two recently proposed parameterizations, those of Robinson et al. (2007) ("ROB") and Grieshop et al. (2009) ("GRI") are compared and evaluated against surface and aircraft measurements. The 3-D model results are assessed by comparing with the concentrations of OA components from Positive Matrix Factorization of Aerosol Mass Spectrometer (AMS) data, and for the first time also with oxygen-to-carbon ratios derived from high-resolution AMS measurements. The results show a substantial enhancement in predicted SOA concentrations (2-4 times) with respect to the previously published base case without S/IVOCs (Hodzic et al., 2009), both within and downwind of the city leading to much reduced discrepancies with the total OA measurements. Model improvements in OA predictions are associated with the better-captured SOA magnitude and diurnal variability. The predicted production from anthropogenic and biomass burning S/IVOC represents 40-60% of the total measured SOA at the surface during the day and is somewhat larger than that from commonly measured aromatic VOCs, especially at the T1 site at the edge of the city. The SOA production from the continued multi-generation S/IVOC oxidation products continues actively downwind. Similar to aircraft observations, the predicted OA/?CO ratio for the ROB case increases from 20-30 ?g sm-3 ppm-1 up to 60-70 ?g sm-3 ppm-1 between a fresh and 1-day aged air mass, while the GRI case produces a 30% higher OA growth than observed. The predicted average O/C ratio of total OA for the ROB case is 0.16 at T0, substantially below observed value of 0.5. A much better agreement for O/C ratios and temporal variability (R2=0.63) is achieved with the updated GRI treatment. Both treatments show a deficiency in regard to POA ageing with a tendency to over-evaporate POA upon dilution of the urban plume suggesting that atmospheric HOA may be less volatile than assumed in these parameterizations. This study highlights the important potential role of S/IVOC chemistry in the SOA budget in this region, and highlights the need for further improvements in available parameterizations. The agreement observed in this study is not sufficient evidence to conclude that S/IVOC are the major missing SOA source in megacity environments. The model is still very underconstrained, and other possible pathways such as formation from very volatile species like glyoxal may explain some of the mass and especially increase the O/C ratio.

  7. Modeling organic aerosols in a megacity: potential contribution of semi-volatile and intermediate volatility primary organic compounds to secondary organic aerosol formation

    SciTech Connect

    Hodzic, Alma; Jimenez, Jose L.; Madronich, Sasha; Canagaratna, M. R.; DeCarlo, Peter F.; Kleinman, Lawrence I.; Fast, Jerome D.

    2010-06-21

    It has been established that observed local and regional levels of secondary organic aerosols (SOA) in polluted areas cannot be explained by the oxidation and partitioning of traditional anthropogenic and biogenic VOC precursors. In this study, the 3D regional air quality model CHIMERE is applied to quantify the contribution to SOA formation of recently identified semi-volatile and intermediate volatility organic vapors (S/IVOC) in and around Mexico City for the MILAGRO field experiment during March 2006. The model has been updated to explicitly include the volatility distribution of primary organic aerosols (POA), their gas-particle partitioning and the gas-phase oxidation of the vapors. Two recently proposed parameterizations, those of Robinson et al. (2007) ("ROB") and Grieshop et al. (2009) ("GRI") are compared and evaluated against surface and aircraft measurements. For the first time, 3D model results are assessed by comparing with the concentrations of OA components from Positive Matrix Factorization of Aerosol Mass Spectrometer (AMS) data, but also against and oxygen-to-carbon ratios derived from high-resolution AMS measurements. The results show a substantial enhancement in predicted SOA concentrations (3-6 times) with respect to the previously published base case without S/IVOCs (Hodzic et al., 2009), both within and downwind of the city leading to much reduced discrepancies with the total OA measurements. The predicted anthropogenic POA levels are found to agree within 20% with the observed HOA concentrations for both the ROB and GRI simulations, consistent with the interpretation of the emissions inventory by previous studies. The impact of biomass burning POA within the city is underestimated in comparison to the AMS BBOA, presumably due to insufficient nighttime smoldering emissions. Model improvements in OA predictions are associated with the better-captured SOA magnitude and diurnal variability. The production from anthropogenic and biomass burning S/IVOC represents 40-60% of the total SOA at the surface during the day and is somewhat larger than that from aromatics, especially at the T1 site at the edge of the city. The downwind SOA production from the continued multi-generation S/IVOC oxidation products actively continues. Similar to aircraft observations, the predicted OA/DCO ratio for the ROB case increases from 20-30 mg sm-3 ppm-1 up to 60-70 mg sm-3 ppm-1 between a fresh and 1-day aged air mass, while the GRI case produces a 30-40% higher OA growth than observed. The predicted average O/C ratio of total OA for the ROB case is 0.16 at T0, substantially below observed value of 0.5. A much better agreement for O/C ratios and temporal variability (R2=0.63) is achieved with the updated GRI treatment. Both treatments show a deficiency in regard to POA evolution with a tendency to over-evaporate POA upon dilution of the urban plume suggesting that atmospheric HOA may be less volatile than assumed in these parameterizations. This study highlights the very important potential role of S/IVOC chemistry in the SOA budget in this region, and highlights the need for improvements in current parameterizations. We note that other proposed pathways of SOA formation such as formation from very volatile species like glyoxal were not included in our simulations, which can also contribute SOA mass and especially increase the O/C ratio.

  8. Modeling organic aerosols in a megacity: Potential contribution of semi-volatile and intermediate volatility primary organic compounds to secondary organic aerosol formation

    SciTech Connect

    Hodzic, A.; Kleinman, L.; Jimenez, J. L.; Madronich, S.; Canagaratna, M. R.; DeCarlo, P. F.; Fast, J.

    2010-06-01

    It has been established that observed local and regional levels of secondary organic aerosols (SOA) in polluted areas cannot be explained by the oxidation and partitioning of anthropogenic and biogenic VOC precursors, at least using current mechanisms and parameterizations. In this study, the 3-D regional air quality model CHIMERE is applied to estimate the potential contribution to SOA formation of recently identified semi-volatile and intermediate volatility organic precursors (S/IVOC) in and around Mexico City for the MILAGRO field experiment during March 2006. The model has been updated to include explicitly the volatility distribution of primary organic aerosols (POA), their gas-particle partitioning and the gas-phase oxidation of the vapors. Two recently proposed parameterizations, those of Robinson et al. (2007) ('ROB') and Grieshop et al. (2009) ('GRI') are compared and evaluated against surface and aircraft measurements. The 3-D model results are assessed by comparing with the concentrations of OA components from Positive Matrix Factorization of Aerosol Mass Spectrometer (AMS) data, and for the first time also with oxygen-to-carbon ratios derived from high-resolution AMS measurements. The results show a substantial enhancement in predicted SOA concentrations (2-4 times) with respect to the previously published base case without S/IVOCs (Hodzic et al., 2009), both within and downwind of the city leading to much reduced discrepancies with the total OA measurements. Model improvements in OA predictions are associated with the better-captured SOA magnitude and diurnal variability. The predicted production from anthropogenic and biomass burning S/IVOC represents 40-60% of the total measured SOA at the surface during the day and is somewhat larger than that from commonly measured aromatic VOCs, especially at the T1 site at the edge of the city. The SOA production from the continued multi-generation S/IVOC oxidation products continues actively downwind. Similar to aircraft observations, the predicted OA/{Delta}CO ratio for the ROB case increases from 20-30 {micro}g sm{sup -3} ppm{sup -1} up to 60-70 {micro}g sm{sup -3} ppm{sup -1} between a fresh and 1-day aged air mass, while the GRI case produces a 30% higher OA growth than observed. The predicted average O/C ratio of total OA for the ROB case is 0.16 at T0, substantially below observed value of 0.5. A much better agreement for O/C ratios and temporal variability (R{sup 2} = 0.63) is achieved with the updated GRI treatment. Both treatments show a deficiency in regard to POA ageing with a tendency to over-evaporate POA upon dilution of the urban plume suggesting that atmospheric HOA may be less volatile than assumed in these parameterizations. This study highlights the important potential role of S/IVOC chemistry in the SOA budget in this region, and highlights the need for further improvements in available parameterizations. The agreement observed in this study is not sufficient evidence to conclude that S/IVOC are the major missing SOA source in megacity environments. The model is still very underconstrained, and other possible pathways such as formation from very volatile species like glyoxal may explain some of the mass and especially increase the O/C ratio.

  9. VOLATILE FATTY ACIDS AND RUMINATION IN THE GOATa M. FOCANT F. GALLOUIN M. LECLERCQ

    E-print Network

    Paris-Sud XI, Université de

    VOLATILE FATTY ACIDS AND RUMINATION IN THE GOATa M. FOCANT F. GALLOUIN M. LECLERCQ Laboratoire de of Baile (1971) revealed the effect of acetate and propionate on the control of feed intake of ruminants, but the effects of VFA on rumination have so far been studied very little. To determine the role of VFA

  10. ACID-VOLATILE SULFIDE AS A FACTOR MEDIATING CADMIUM AND NICKEL BIOAVAILABILITY IN CONTAMINATED SEDIMENTS

    EPA Science Inventory

    We investigated the influence of sulfide, measured as acid-volatile sulfide (AVS), on the bioavailability of cadmium and nickel in sediments. eventeen samples from an estuarine system heavily contaminated with cadmium and nickel were analyzed for AVS and simultaneously extracted ...

  11. Acid-volatile sulfide as a factor mediating cadmium and nickel bioavailability in contaminated sediments

    Microsoft Academic Search

    Gerald T. Ankley; Gary L. Phipps; Edward N. Leonard; Duane A. Benoit; Vincent R. Mattson; Patricia A. Kosian; Anne M. Cotter; Joseph R. Dierkes; David J. Hansen; John D. Mahony

    1991-01-01

    The authors investigated the influence of sulfide, measured as acid-volatile sulfide (AVS), on the bioavailability of cadmium and nickel in sediments. Seventeen samples from an estuarine system heavily contaminated with cadmium and nickel were analyzed for AVS and simultaneously extracted metals (SEM) and tested in 10-d exposures with the amphipod Hyalella azteca and the oligochaete Lumbriculus variegatus. Molar SEM(cadmium +

  12. A modified steam distillation method for volatile acids determination in anaerobic digestors

    Microsoft Academic Search

    S. P. Tsonis

    1991-01-01

    A modified steam distillation method for the accurate determination of low levels of volatile acids found primarily in low rate anaerobic digestors has been developed. The interference of bicarbonate alkalinity is minimal with complete removal of carbon dioxide from the sample prior to distillation. This removal can be achieved by boiling the acidified sample for 30 min in an erlenmeyer

  13. Relationship of soluble solids, acidity and aroma volatiles to flavor in late-season navel oranges

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Navel orange flavor development during early fruit maturation is strongly dependent on changes in soluble solids concentration (SSC) and titratable acidity (TA), while later in the season other factors, such as aroma volatiles, also become important. The flavor of individual oranges can differ gre...

  14. PRODUCTION OF VOLATILE FATTY ACIDS BY STRICTLY ANAEROBIC BACTERIA IN THE DIGESTIVE TRACT OF GNOTOXENIC MICE.

    E-print Network

    Paris-Sud XI, Université de

    SUMMARY PRODUCTION OF VOLATILE FATTY ACIDS BY STRICTLY ANAEROBIC BACTERIA IN THE DIGESTIVE TRACT OF « GNOTOXENIC » MICE. INHIBITORY EFFECT ON SHIGELLA FLEXNERI Various strains of strictly anaerobic bacteria of holoxenic animals, were implanted in the digestive tract of axenic mice. The in vivo production of VFA

  15. Effects on milk yield and composition of infusions of volatile fatty acids and caseinate into

    E-print Network

    Paris-Sud XI, Université de

    Effects on milk yield and composition of infusions of volatile fatty acids and caseinate Laitière, Saint-Gilles, 35590 L'Hermitage, France Changes in milk secretion and composi- tion, particularly concentrate and 7.5% soya bean meal. Duodenal infusion of casein increased milk yield (+ 1.9 kg

  16. A reassessment of the budget of formic and acetic acids in the boundary layer at Dumont d'Urville (coastal Antarctica): The role of penguin emissions on the budget of several oxygenated volatile organic compounds

    NASA Astrophysics Data System (ADS)

    Legrand, Michel; Gros, ValéRie; Preunkert, Susanne; Sarda-EstèVe, Roland; Thierry, Anne-Mathilde; PéPy, Guillaume; Jourdain, B.

    2012-03-01

    Initiated in 1997, the year-round study of formic and acetic acids was maintained until 2011 at the coastal Antarctic site of Dumont d'Urville. The records show that formic and acetic acids are rather abundant in summer with typical mixing ratios of 200 pptv and 700 pptv, respectively. With the aim to constrain their budget, investigations of their potential marine precursors like short-chain alkenes and acetaldehyde were initiated in 2011. Acetic acid levels in December 2010 were four times higher than those observed over summers back to 1997. These unusually high levels were accompanied by unusually high levels of ammonia, and by an enrichment of oxalate in aerosols. These observations suggest that the guano decomposition in the large penguin colonies present at the site was particularly strong under weather conditions encountered in spring 2010 (important snow storms followed by sunny days with mild temperatures). Although being dependent on environmental conditions, this process greatly impacts the local atmospheric budget of acetic acid, acetaldehyde, and acetone during the entire summer season. Present at levels as high as 500 pptv, acetaldehyde may represent the major precursor of acetic acid, alkene-ozone reactions remaining insignificant sources. Far less influenced by penguin emissions, the budget of formic acid remains not fully understood even if alkene-ozone reactions contribute significantly.

  17. Electrical conductivity of mixed structures based on conjugated organic materials and metals oxides upon adsorption of volatile organic compounds

    NASA Astrophysics Data System (ADS)

    Komolov, A. S.; Gerasimova, N. B.; Lazneva, É. F.; Akhremchik, S. N.

    2009-08-01

    This paper reports on the results of investigations of the electrophysical characteristics of films based on conjugated organic molecules of copper phthalocyanine (CuPc) and the perylene derivative 3,4,9,10-perylenetetracarboxylic acid dianhydride mixed with TiO2 microparticles and SnO2 nanoparticles. The electrical resistivity of the mixed films under investigation lies in the range from 5 × 108 to 5 × 109 GQ cm. The influence of adsorption on the surface of the films on the electrical conductivity is studied using vapors of water and volatile organic compounds, such as ethanol, ammonia, toluene, and acetone, at pressures in the range from 10-1 to 10 Pa. The adsorption of acetone and toluene vapors does not lead to considerable changes in the electrical conductivity of the films, whereas the exposure to vapors of water, ethanol, and ammonia results in a reversible multiple increase in the electrical conductivity of the studied films. In the case of mixed CuPc/TiO2 films, the electrical conductivity observed upon adsorption of ammonia vapors on the film surface exceeds the initial conductivity by a factor of approximately 2500. The mechanisms of the observed changes in the electrical conductivity are discussed with allowance made for the increase in the electron density of the films due to the electron exchange with adsorbed molecules of reducing gases.

  18. Determination of volatile organic profiles and photochemical potentials from chemical manufacture process vents.

    PubMed

    Hsu, Yi-Chyun; Chen, Shan-Kun; Tsai, Jiun-Horng; Chiang, Hung-Lung

    2007-06-01

    The main objective of this study was to monitor the volatile organic compounds (VOCs) in the stack gas released from organic chemical industrial plants to determine emission factors. Samples from 52 stacks, with or without air pollution control devices (APCDs), from seven industrial processes were taken and VOCs measured using U.S. Environmental Protection Agency (EPA) Method 18. These 7 processes, including 26 plants, were the manufacturers of acrylonitrile-butadiene-styrene (ABS), polyvinyl chloride (PVC), polystyrene (PS), acrylic resin (ACR), vinyl chloride (VC), para-terephthalic acid (PTA), and synthetic fiber (SYF). The results clearly indicate significant variations of emission factors among the various industrial processes, particularly emission factors for those without APCDs. As expected, those with APCDs yield much less emission factors. Regardless of those with or without APCDs, the order of manufacturing processes with regard to VOC emission factors is SYF > ABS > PS >ACR > PTA > PVC > VC. The emission factors for some processes also differ from those in EPA-42 data file. The VOC profiles further indicate that some VOCs are not listed in the U.S. VOC/Particulate Matter Speciation Data System (SPECIATE). The potential O3 formation is determined from the total amount of VOC emitted for each of seven processes. The resultant O3 yield varied from 0.22 (ACR) to 2.33 g O3 g(-1) VOC (PTA). The significance of this O3 yield is discussed. PMID:17608005

  19. A Genetically-Based Latitudinal Cline in the Emission of Herbivore-Induced Plant Volatile Organic Compounds

    E-print Network

    Agrawal, Anurag

    in a common garden near the range center. Feeding by specialist Danaus plexippus (monarch) larvae induced VOCs gradient . Monarch butterfly Danaus plexippus . Volatile organic compounds Introduction Geographic patterns

  20. Acetic Acid Acts as a Volatile Signal To Stimulate Bacterial Biofilm Formation

    PubMed Central

    Chen, Yun; Gozzi, Kevin; Yan, Fang

    2015-01-01

    ABSTRACT Volatiles are small air-transmittable chemicals with diverse biological activities. In this study, we showed that volatiles produced by the bacterium Bacillus subtilis had a profound effect on biofilm formation of neighboring B. subtilis cells that grew in proximity but were physically separated. We further demonstrated that one such volatile, acetic acid, is particularly potent in stimulating biofilm formation. Multiple lines of genetic evidence based on B. subtilis mutants that are defective in either acetic acid production or transportation suggest that B. subtilis uses acetic acid as a metabolic signal to coordinate the timing of biofilm formation. Lastly, we investigated how B. subtilis cells sense and respond to acetic acid in regulating biofilm formation. We showed the possible involvement of three sets of genes (ywbHG, ysbAB, and yxaKC), all encoding putative holin-antiholin-like proteins, in cells responding to acetic acid and stimulating biofilm formation. All three sets of genes were induced by acetate. A mutant with a triple mutation of those genes showed a severe delay in biofilm formation, whereas a strain overexpressing ywbHG showed early and robust biofilm formation. Results of our studies suggest that B. subtilis and possibly other bacteria use acetic acid as a metabolic signal to regulate biofilm formation as well as a quorum-sensing-like airborne signal to coordinate the timing of biofilm formation by physically separated cells in the community. PMID:26060272

  1. Evaluation of Volatilization by Organic Chemicals Residing Below the Soil Surface

    NASA Astrophysics Data System (ADS)

    Jury, William A.; Russo, David; Streile, Gary; El Abd, Hesham

    1990-01-01

    Although volatile organic compounds located in buried waste repositories or distributed through the unsaturated soil zone have the potential to migrate to the atmosphere by vapor diffusion, little attention has been paid in the past to estimating the importance of volatilization losses. In this paper a screening model is introduced which evaluates the relative volatilization losses of a number of organic compounds under standard soil conditions. The model is an analytic solution to the problem wherein the organic chemical is located at time zero at uniform concentration in a finite layer of soil covered by a layer of soil devoid of chemical. The compound is assumed to move by vapor or liquid diffusion and by mass flow under the influence of steady upward or zero water flow while undergoing first-order degradation and linear equilibrium adsorption. Loss to the atmosphere is governed by vapor diffusion through a stagnant air boundary layer. Calculations are performed on 35 organic compounds in two model soils with properties characteristic of sandy and clayey soil. The model identifies those compounds with high potential for loss during 1 year after incorporation under 100 cm of soil cover and also is used to calculate the minimum soil cover thickness required to reduce volatilization losses to insignificant levels during the lifetime of the compound in the soil. From the latter calculation it was determined that certain compounds may volatilize from deep subsurface locations or even groundwater unless the soil surface is sealed to prevent gas migration.

  2. A screening assessment of emissions of volatile organic compounds and particles from heated indoor dust samples.

    PubMed

    Pedersen, E K; Bjørseth, O; Syversen, T; Mathiesen, M

    2003-06-01

    This paper characterizes and compares emissions during heating of different dust samples relevant to the indoor environment. Characterization includes emission of volatile organic compounds when dust samples were heated to 150 and 250 degrees C (gas chromatograph-mass spectrometer), weight loss during heating to 450 degrees C (thermogravimetric analysis), and the number of particles emitted during heating towards 200 degrees C (condensation nucleus counting). Element analyses were performed for non-heated dust (inductively coupled plasma discharge instrument). Emissions of volatile organic compounds from heated dust from different sources were surprisingly similar. However, the temperature at which the emission of volatiles started varied with the dust source. For most of the samples studied, the emissions were considerable already at 150 degrees C, and increased in number of peaks and peak area at 250 degrees C. Particle emissions started around 70 degrees C regardless of the dust source. Particle emissions seemed to be affected by the content of organic material. PMID:12756004

  3. Ion-trap detection of volatile organic compounds in alveolar breath

    SciTech Connect

    Phillips, M.; Greenberg, J. (Department of Medicine, St. Vincent's Medical Center of Richmond, Staten Island, NY (United States))

    1992-01-01

    We describe a method for the collection and microanalysis of the volatile organic compounds in human breath. A transportable apparatus supplies subjects with purified air and samples their alveolar breath; the volatile organic compounds are captured in an adsorptive trap containing activated carbon and molecular sieve. The sample is thermally desorbed from the trap in an automated microprocessor-controlled device, concentrated by two-stage cryofocusing, and assayed by gas chromatography with ion-trap detection. Compounds are identified by reference to a computer-based library of mass spectra with subtraction of the background components present in the inspired air. We used this device to study 10 normal subjects and determined the relative abundance of the volatile organic compounds in their alveolar breath. The breath-collecting apparatus was convenient to operate and was well tolerated by human volunteers.

  4. Effects of NOx on the volatility of secondary organic aerosol from isoprene photooxidation.

    PubMed

    Xu, Lu; Kollman, Matthew S; Song, Chen; Shilling, John E; Ng, Nga L

    2014-02-18

    The effects of NOx on the volatility of the secondary organic aerosol (SOA) formed from isoprene photooxidation are investigated in environmental chamber experiments. Two types of experiments are performed. In HO2-dominant experiments, organic peroxy radicals (RO2) primarily react with HO2. In mixed experiments, RO2 reacts through multiple pathways, including with NO, NO2, and HO2. The volatility and oxidation state of isoprene SOA are sensitive to and exhibit a nonlinear dependence on NOx levels. Depending on the NOx levels, the SOA formed in mixed experiments can be of similar or lower volatility compared to that formed in HO2-dominant experiments. The dependence of SOA yield, volatility, and oxidation state on the NOx level likely arises from gas-phase RO2 chemistry and succeeding particle-phase oligomerization reactions. The NOx level also plays a strong role in SOA aging. While the volatility of SOA in mixed experiments does not change substantially over time, SOA becomes less volatile and more oxidized as oxidation progresses in HO2-dominant experiments. PMID:24471688

  5. 1.5-Dimensional volatility basis set approach for modeling organic aerosol in CAMx and CMAQ

    NASA Astrophysics Data System (ADS)

    Koo, Bonyoung; Knipping, Eladio; Yarwood, Greg

    2014-10-01

    A hybrid volatility basis set (VBS) approach to modeling atmospheric organic aerosol (OA) is developed that combines the simplicity of the 1-dimensional (1-D) VBS with the ability to describe evolution of OA in the 2-dimensional space of oxidation state and volatility. This 1.5-D scheme uses four basis sets to describe varying degrees of oxidation in ambient OA: two basis sets for chemically aged oxygenated OA (anthropogenic and biogenic) and two for freshly emitted OA (from anthropogenic sources and biomass burning). Each basis set has five volatility bins including a zero-volatility bin for essentially non-volatile compounds. The scheme adjusts oxidation state as well as volatility in response to chemical aging by simplifying the 2-dimensional VBS model. The 1.5-D VBS module is implemented in two widely used photochemical grid models (CAMx and CMAQ) and evaluated for summer and winter 2005 episodes over the eastern U.S. CAMx performs reasonably well in predicting observed organic carbon (OC) concentrations while CMAQ under-estimates OC, with differences between models being attributed to science algorithms other than the VBS. Oxygenated OA accounts for less than half of the modeled OA mass in winter but about 80% of total OA in summer due to more rapid chemical aging in summer.

  6. HS-SPME/GC-MS analysis of volatile and semi-volatile organic compounds emitted from municipal sewage sludge.

    PubMed

    Kotowska, Urszula; ?alikowski, Maciej; Isidorov, Valery A

    2012-05-01

    The aim of the research involved identification and semi-quantitative determination of unknown volatile and semi-volatile organic compounds emitted to air by sewage sludge formed in the process of municipal wastewater treatment in a sewage treatment plant. Samples taken directly after completion of the technological process as well as the sludge stored on the premise of the sewage treatment plant were analyzed. A simple method using off-line headspace solid-phase microextraction combined with gas chromatography-mass spectrometry has been proposed for extraction and detection of organic pollutants. For reliable identification of compounds, combination of two independent parameters: mass spectra and linear temperature programmed retention indices were employed. Over 170 compounds of different structure were identified including aliphatic and aromatic hydrocarbons, alcohols, esters, carbonyls, as well as sulfur, nitrogen, and chlorine containing compounds. The prevailing substances included: ethyl ether, n-hexane, p-xylene, o-xylene, mesitylene, m-ethylbenzene, limonene, n-decane, n-undecane, and n-dodecane. A few compounds such as methanetiol, dimethyl polisulfide, octaatomic sulfur, phthalic anhydride, and indoles were identified in the sludge for the first time. PMID:21688031

  7. Volatile organic compounds of polyethylene vinyl acetate plastic are toxic to living organisms.

    PubMed

    Meng, Tingzhu Teresa

    2014-01-01

    Volatile organic compounds (VOCs) in polyvinyl chloride (PVC) plastic products readily evaporate; as a result, hazardous gases enter the ecosystem, and cause cancer in humans and other animals. Polyethylene vinyl acetate (PEVA) plastic has recently become a popular alternative to PVC since it is chlorine-free. In order to determine whether PEVA is harmful to humans, this research employed the freshwater oligochaete Lumbriculus variegatus as a model to compare their oxygen intakes while they were exposed to the original stock solutions of PEVA, PVC or distilled water at a different length of time for one day, four days or eight days. During the exposure periods, the oxygen intakes in both PEVA and PVC groups were much higher than in the distilled water group, indicating that VOCs in both PEVA and PVC were toxins that stressed L. variegatus. Furthermore, none of the worms fully recovered during the24-hr recovery period. Additionally, the L. variegatus did not clump together tightly after four or eight days' exposure to either of the two types of plastic solutions, which meant that both PEVA and PVC negatively affected the social behaviors of these blackworms. The LD50 tests also supported the observations above. For the first time, our results have shown that PEVA plastic has adverse effects on living organisms, and therefore it is not a safe alternative to PVC. Further studies should identify specific compounds causing the adverse effects, and determine whether toxic effect occurs in more complex organisms, especially humans. PMID:25242410

  8. Volatile organic compounds produced during irradiation of mail.

    PubMed

    Smith, Philip A; Sheely, Michael V; Hakspiel, Shelly J; Miller, Stephen

    2003-01-01

    In 2001, Bacillus anthracis spores were delivered through the United States postal system in a series of bioterrorist acts. Controls proposed for this threat included sanitization with high-energy electrons. Solid phase microextraction was used with gas chromatography/mass spectrometry for field sampling and analysis of volatile compounds apparently produced from polymeric materials such as cellulose and plastics, immediately following processing of mail at a commercial irradiation facility. Solid phase microextraction and direct sampling of air into a cryogenically cooled temperature programmable inlet were used in the laboratory for gas chromatography/mass spectrometry analysis of air in contact with irradiated mail, envelopes only (packaged identically to mail), and air inside irradiated plastic mail packaging bags (with neither mail nor envelopes). Irradiated mail or envelope systems produced hydrocarbons such as propane, butane, pentane, hexane, heptane, methylpentanes, and benzene; and oxygen-containing compounds such as acetaldehyde, acrolein, propionaldehyde, furan, 2-methylfuran, methanol, acetone, 2-butanone, and ethanol. In addition to hydrocarbons, methyl and ethyl nitrate were detected in irradiated bags that contained only air, suggesting reactive nitrogen species formed from air irradiation reacted with hydroxy-containing compounds to give nitro esters. The similarities of volatile compounds in irradiated systems containing paper to those observed by researchers studying cellulose pyrolysis suggests common depolymerization and degradation mechanisms in each case. These similarities should guide additional work to examine irradiated mail for chemical compounds not detectable by methods used here. PMID:12688843

  9. Preparation of spiked soils by vapor fortification for volatile organic compounds analysis

    SciTech Connect

    Hewitt, A.D. [Army Cold Regions Research and Engineering Lab., Hanover, NH (United States)

    1994-05-01

    This paper describes a vapor fortification method for preparing quality assurance/quality control soils for volatile organic compound analysis. Treatment of soils with volatile organic compounds occurs in a closed container in a manner somewhat analogous to the way the vadose zone often becomes contaminated. One advantage of this method for preparing soils for quality assurance/quality control purposes is that the efficiency of various extraction methods can be reliably compared. Furthermore, by substantially reducing the error due to sample inhomogeneity, the error associated with the determinative step can also be properly evaluated. 15 refs., 3 tabs.

  10. Feasibility study of preparing performance evaluation soils for analyzing volatile organic compounds. Special report

    SciTech Connect

    Hewitt, A.D.

    1993-05-01

    Vapor fortification, an alternative method for spiking soils with volatile organic compounds for quality assurance/quality control, was improved by minimizing the effects of numerous variables. The procedure developed resulted in average analytes concentrations for triplicate test samples that were not significantly different among three separate fortification treatments, and had relative standard deviations within each treatment of less than 9%, for three of the four analytes tested. The advantages of using vapor fortification instead of the conventional liquid injection methods are discussed. Performance evaluation soils, Vapor fortification, Pollution control, Volatile organic compounds.

  11. Thermal engine driven heat pump for recovery of volatile organic compounds

    DOEpatents

    Drake, Richard L. (Schenectady, NY)

    1991-01-01

    The present invention relates to a method and apparatus for separating volatile organic compounds from a stream of process gas. An internal combustion engine drives a plurality of refrigeration systems, an electrical generator and an air compressor. The exhaust of the internal combustion engine drives an inert gas subsystem and a heater for the gas. A water jacket captures waste heat from the internal combustion engine and drives a second heater for the gas and possibly an additional refrigeration system for the supply of chilled water. The refrigeration systems mechanically driven by the internal combustion engine effect the precipitation of volatile organic compounds from the stream of gas.

  12. Emission of volatile organic compounds from composting of different solid wastes: Abatement by biofiltration

    Microsoft Academic Search

    Estela Pagans; Antoni Sánchez

    2006-01-01

    Emission of volatile organic compounds (VOCs) produced during composting of different organic wastes (source-selected organic fraction of municipal solid wastes (OFMSW), raw sludge (RS) and anaerobically digested wastewater sludge (ADS) and animal by-products (AP)) and its subsequent biofiltration have been studied. Composting was performed in a laboratory scale composting plant (30l) and the exhaust gases generated were treated by means

  13. The Amazonian Floodplains, an ecotype with challenging questions on volatile organic compound (VOC) emissions

    NASA Astrophysics Data System (ADS)

    Kesselmeier, J.

    2012-12-01

    Volatile organic compound (VOC) emissions are affected by a variety of biotic and abiotic factors such as light intensity, temperature, CO2 and drought. Another factor usually overlooked but very important for the tropical rainforest in Amazonia is regular flooding. According to recent estimates, the total Amazonian floodplain area easily ranges up to 700,000 km^2, including whitewater river floodplains (várzea) blackwater regions (igapó) and further clearwater regions. Regarding the total Amazonian wetlands the area sums up to more than 2.000.000 km^2, i.e. 30% of Amazonia. To survive the flooding periods causing anoxic conditions for the root system of up to several months, vegetation has developed several morphological, anatomical and physiological strategies. One is to switch over the root metabolism to fermentation, thus producing ethanol as one of the main products. Ethanol is a toxic metabolite which is transported into the leaves by the transpiration stream. From there it can either be directly emitted into the atmosphere, or can be re-metabolized to acetaldehyde and/or acetate. All of these compounds are volatile enough to be partly released into the atmosphere. We observed emissions of ethanol, acetaldehyde and acetic acid under root anoxia. Furthermore, plant stress induced by flooding also affected leaf primary physiological processes as well as other VOC emissions such as the release of isoprenoids and other volatiles. For example, Hevea spruceana could be identified as a monoterpene emitting tree species behaving differently upon anoxia depending on the origin, with increasing emissions of the species from igapó and decreasing with the corresponding species from várzea. Contrasting such short term inundations, studies of VOC emissions under long term conditions (2-3 months) did not confirm the ethanol/acetaldehyde emissions, whereas emissions of other VOC species decreased considerably. These results demonstrate that the transfer of our knowledge based on short-term experiments is risky being transferred to an ecotype which is governed under natural conditions by long term flooding. Furthermore, contrasting such experiments with usually young trees (saplings or a few years old) nothing is known about the emission behavior of adult trees under field conditions.

  14. Arachidonic acid-dependent carbon-eight volatile synthesis from wounded liverwort (Marchantia polymorpha).

    PubMed

    Kihara, Hirotomo; Tanaka, Maya; Yamato, Katsuyuki T; Horibata, Akira; Yamada, Atsushi; Kita, Sayaka; Ishizaki, Kimitsune; Kajikawa, Masataka; Fukuzawa, Hideya; Kohchi, Takayuki; Akakabe, Yoshihiko; Matsui, Kenji

    2014-11-01

    Eight-carbon (C8) volatiles, such as 1-octen-3-ol, octan-3-one, and octan-3-ol, are ubiquitously found among fungi and bryophytes. In this study, it was found that the thalli of the common liverwort Marchantia polymorpha, a model plant species, emitted high amounts of C8 volatiles mainly consisting of (R)-1-octen-3-ol and octan-3-one upon mechanical wounding. The induction of emission took place within 40min. In intact thalli, 1-octen-3-yl acetate was the predominant C8 volatile while tissue disruption resulted in conversion of the acetate to 1-octen-3-ol. This conversion was carried out by an esterase showing stereospecificity to (R)-1-octen-3-yl acetate. From the transgenic line of M. polymorpha (des6(KO)) lacking arachidonic acid and eicosapentaenoic acid, formation of C8 volatiles was only minimally observed, which indicated that arachidonic and/or eicosapentaenoic acids were essential to form C8 volatiles in M. polymorpha. When des6(KO) thalli were exposed to the vapor of 1-octen-3-ol, they absorbed the alcohol and converted it into 1-octen-3-yl acetate and octan-3-one. Therefore, this implied that 1-octen-3-ol was the primary C8 product formed from arachidonic acid, and further metabolism involving acetylation and oxidoreduction occurred to diversify the C8 products. Octan-3-one was only minimally formed from completely disrupted thalli, while it was formed as the most abundant product in partially disrupted thalli. Therefore, it is assumed that the remaining intact tissues were involved in the conversion of 1-octen-3-ol to octan-3-one in the partially disrupted thalli. The conversion was partly promoted by addition of NAD(P)H into the completely disrupted tissues, suggesting an NAD(P)H-dependent oxidoreductase was involved in the conversion. PMID:25174554

  15. Organic Phosphoric Acid of the Soil. 

    E-print Network

    Fraps, G. S. (George Stronach)

    1911-01-01

    of the Soil. 131 Hog Feeding Experiments. 132 Co-operative Forage Crop Work. 133 Commercial Fertilizer. First, Second, Fourth, Fifth, Eighth, Ninth, Tenth, Eleventh Thirteenth Annual Reports. ORGANIC PHOSPHORIC ACID OF THE SOIL. 1 By G. S. Praps... portion of the soil is ignited, extracted with cold 12 per cent hydrochloric acid, and the phosphoric acid estimated. From this is subtracted the amount of phosphoric acid extracted from the original soil by the same process, and the result is +~1ran...

  16. Alcohol, volatile fatty acid, phenol, and methane emissions from dairy cows and fresh manure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There are approximately 2.5 million dairy cows in California. Emission inventories list dairy cows and their waste as the major source of regional air pollutants, but data on their actual emissions remain sparse, particularly for smog-forming volatile organic compounds (VOC) and greenhouse gases (GH...

  17. Anaerobic degradation of volatile fatty acids at different sulphate concentrations

    Microsoft Academic Search

    A. Visser; I. Beeksma; F. van der Zee; A. J. M. Stams; G. Lettinga

    1993-01-01

    The effect of sulfate on the anaerobic breakdown of mixtures of acetate, propionate and butyrate at three different sulfate to fatty acid ratios was studied in upflow anaerobic sludge blanket reactors. Sludge characteristics were followed with time by means of sludge activity tests and by enumeration of the different physiological bacterial groups. At each sulfate concentration acetate was completely converted

  18. Immunological detection of mellitic acid in the Atacama desert: Implication for organics detection on Mars

    NASA Astrophysics Data System (ADS)

    Blanco, Yolanda; Rivas, Luis A.; Ruiz-Bermejo, Marta; Parro, Víctor

    2013-06-01

    The restrictions imposed by instrumentation and some methodological constraints make that only volatile organic compounds have been analyzed by in situ instruments in planetary exploration. It has been argued that polycarboxilic acids like the hexacarboxylic acid (mellitic acid) can be produced and accumulated in the martian regolith from the oxidation of meteoritic organic matter. However, these compounds are non-volatile and instruments designed for the analysis of volatile compounds would not detect them. Herein we report the production of an antibody to mellitic acid and the development of a fluorescent inhibition microarray immunoassay (IMI) to detect this substance to a limit of 5 ppb (ng mL-1). We used the anti-mellitic antibody to detect mellitic acid in drill core samples obtained from different depths in the Atacama desert (Chile), a highly relevant terrestrial analogue for Mars. The presence of mellitic acid was corroborated by organic extraction and GC/MS analysis. Our results showed a smooth gradient of mellitic acid concentration, being higher at the surface and near the surface (1.17-1.57 ppm) and diminishing with depth to be undetectable at a depth of 4 m. Our immunoassay can be easily implemented in instruments for in situ analysis.

  19. Volatile organic compounds (VOCs): Remediation for wastewater. (Latest citations from the Selected Water Resources Abstracts database). Published Search

    SciTech Connect

    Not Available

    1993-11-01

    The bibliography contains citations concerning wastewater contamination by volatile organic materials and the technology for reclamation. Remediation techniques discussed include use of activated carbon, activated sludge, oxidation, scrubbing, vapor stripping, biodegradation, and other degradative treatments. Articles include remediation of soils contaminated by volatile wastes. The citations examine a variety of compounds, including aromatic hydrocarbons, petroleum wastes, chlorinated organics, and other volatile materials. (Contains a minimum of 215 citations and includes a subject term index and title list.)

  20. Multisorbent tubes for collecting volatile organic compounds in spacecraft air

    NASA Technical Reports Server (NTRS)

    Matney, M. L.; Beck, S. W.; Limero, T. F.; James, J. T.

    2000-01-01

    The sampling capability of Tenax-TA tubes, used in the National Aeronautics and Space Administration's solid sorbent air sampler to trap and concentrate contaminants from air aboard spacecraft, was improved by incorporating two sorbents within the tubes. Existing tubes containing only Tenax-TA allowed highly volatile compounds to "break through" during collection of a 1.5 L air sample. First the carbon molecular sieve-type sorbents Carboxen 569 and Carbosieve S-III were tested for their ability to quantitatively trap the highly volatile compounds. Breakthrough volumes were determined with the direct method, whereby low ppm levels of methanol or Freon 12 in nitrogen were flowed through the sorbent tubes at 30 mL/min, and breakthrough was detected by gas chromatography. Breakthrough volumes for methanol were about 9 L/g on Carboxen 569 and 11 L/g on Carbosieve S-III; breakthrough volumes for Freon 12 were about 7 L/g on Carboxen 569 and > 26 L/g on Carbosieve S-III. Next, dual-bed tubes containing either Tenax-TA/Carbosieve S-III, Tenax-TA/Carboxen 569, or Carbotrap/Carboxen 569 to a 10-component gas mixture were exposed, in dry and in humidified air (50% relative humidity), and percentage recoveries of each compound were determined. The Tenax-TA/Carboxen 569 combination gave the best overall recoveries (75-114% for the 10 compounds). Acetaldehyde had the lowest recovery (75%) of the 10 compounds, but this value was still an improvement over either the other two sorbent combinations or the original single-sorbent tubes.

  1. Meeting new air standards with a volatile organic treatment train

    Microsoft Academic Search

    J. S. Bowers; D. Dennison; G. May

    1995-01-01

    The U.S. Environmental Protection Agency (EPA) issued the second phase of the organic air emission standards for hazardous waste treatment, storage, and disposal facilities (TSDFs) and hazardous waste generators in December 1994. These standards (referred to as the Subpart CC standards) are designed to further reduce organic air emissions from hazardous waste management activities. To comply with these new air

  2. Epidemiology and toxicology of volatile organic chemical contaminants in water absorbed through the skin

    SciTech Connect

    Thomas, R.D. (National Academy of Sciences, Washington, DC (USA))

    1989-10-01

    This paper provides a general introduction to the occurrence, epidemiology, and toxicity of some of the most common contaminants of water supplies, the volatile organic chemicals (VCs). VOCs are formed from the reaction of chlorine during disinfection with naturally occurring carbon in the form of humic acids. The VOCs may also enter water supplies as a result of manufacturing, processing, distribution, and urban and agricultural runoff. Their occurrence is summarized. No epidemiologic studies examine the health effects where skin is the sole route of exposure. However, several studies are reviewed where skin is one of the routes of exposure for VOCs. Finally, the toxicity of some of the more important VOCS is outlined, including chloroform, trichloroethylene, tetrachloroethylene, carbon tetrachloride, benzene, and alkylbenzenes. Where possible, similarities in toxicity between individual members of this class of chemical contaminates are noted. There are striking similarities of toxicity of various VOCs in the liver, kidney, and hematopoietic system. These similarities should be considered as skin exposure models are being developed. 72 refs., 1 fig., 6 tabs.

  3. Volatile organic compound emissions from elephant grass and bamboo cultivars used as potential bioethanol crop

    NASA Astrophysics Data System (ADS)

    Crespo, E.; Graus, M.; Gilman, J. B.; Lerner, B. M.; Fall, R.; Harren, F. J. M.; Warneke, C.

    2013-02-01

    Volatile organic compound (VOC) emissions from elephant grass (Miscanthus gigantus) and black bamboo (Phyllostachys nigra) were measured online in semi-field chamber and plant enclosure experiments during growth and harvest using proton-transfer reaction mass spectrometry (PTR-MS), proton-transfer reaction ion-trap mass spectrometry (PIT-MS) and gas chromatography-mass spectrometry (GC-MS). Both cultivars are being considered for second-generation biofuel production. Before this study, no information was available on their yearly VOC emissions. This exploratory investigation shows that black bamboo is a strong isoprene emitter (daytime 28,516 ng gdwt-1 h-1) and has larger VOC emissions, especially for wound compounds from the hexanal and hexenal families, than elephant grass. Daytime emissions of methanol, acetaldehyde, acetone + propanal and acetic acid of black bamboo were 618, 249, 351, and 1034 ng gdwt-1 h-1, respectively. In addition, it is observed that elephant grass VOC emissions after harvesting strongly depend on the seasonal stage. Not taking VOC emission variations throughout the season for annual and perennial species into account, may lead to an overestimation of the impact on local air quality in dry periods. In addition, our data suggest that the use of perennial grasses for extensive growing for biofuel production have lower emissions than woody species, which might be important for regional atmospheric chemistry.

  4. 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.

  5. Exhaled volatile organic compounds as lung cancer biomarkers during one-lung ventilation

    PubMed Central

    Wang, Changsong; Dong, Ran; Wang, Xiaoyang; Lian, Ailing; Chi, Chunjie; Ke, Chaofu; Guo, Lei; Liu, Shanshan; Zhao, Wei; Xu, Guowang; Li, Enyou

    2014-01-01

    In this study, single-lung ventilation was used to detect differences in the volatile organic compound (VOCs) profiles between lung tissues in healthy and affected lungs. In addition, changes that occurred after lung cancer resection in both the VOCs profiles of exhaled breath from ipsilateral and contralateral lungs and the VOCs profiles of exhaled breath and blood sample headspaces were also determined. Eighteen patients with non-small cell carcinoma were enrolled. Alveolar breath samples were taken separately from healthy and diseased lungs before and after the tumor resection. Solid phase microextraction–gas chromatography/mass spectrometry was used to assess the exhaled VOCs of the study participants. The VOCs exhibited significant differences between the contralateral and ipsilateral lungs before surgery, the contralateral and ipsilateral lungs after surgery, the ipsilateral lungs before and after surgery, and the blood samples from before and after surgery; 12, 19, 12 and 5 characteristic metabolites played decisive roles in sample classification, respectively. 2,2-Dimethyldecane, tetradecane, 2,2,4,6,6-pentamethylheptane, 2,3,4-trimethyldecane, nonane, 3,4,5,6-tetramethyloctane, and hexadecane may be generated from lipid peroxidation during surgery. Caprolactam and propanoic acid may be more promising exhaled breath biomarkers for lung cancer. PMID:25482491

  6. Tunable volatile organic compounds sensor by using thiolated ligand conjugation on MoS2.

    PubMed

    Kim, Jong-Seon; Yoo, Hae-Wook; Choi, Hyung Ouk; Jung, Hee-Tae

    2014-10-01

    One of the most important issues in the development of gas sensors for breath analysis is the fabrication of gas sensor arrays that possess different responses for recognizing patterns for volatile organic compounds (VOCs). Here, we develop a high-performance chemiresistor with a tunable sensor response and high sensitivity for representative VOC groups by using molybdenum disulfide (MoS2) and by conjugating a thiolated ligand (mercaptoundecanoic acid (MUA)) to MoS2 surface. Primitive and MUA-conjugated MoS2 sensing channels exhibit distinctly different sensor responses toward VOCs. In particular, the primitive MoS2 sensor presents positive responses for oxygen-functionalized VOCs, while the MUA-conjugated MoS2 sensor presents negative responses for the same analytes. Such characteristic sensor responses demonstrate that ligand conjugation successfully adds functionality to a MoS2 matrix. Thus, this will be a promising approach to constructing a versatile sensor array, by conjugating a wide variety of thiolated ligands on the MoS2 surface. Furthermore, these MoS2 sensors in this study exhibit high sensitivity to representative VOCs down to a concentration of 1 ppm. This approach to fabricating a tunable and sensitive VOC sensor may lead to a valuable real-world application for lung cancer diagnosis by breath analysis. PMID:25191976

  7. Removal of volatile organic compounds by heterogeneous ozonation on microporous synthetic alumina silicate.

    PubMed

    Brodu, Nicolas; Zaitan, Hicham; Manero, Marie-Hélène; Pic, Jean-Stéphane

    2012-01-01

    A hybrid process combining adsorption and ozonation was examined as an alternative treatment for odorous volatile organic compounds (VOCs). Methyl ethyl ketone (MEK) was chosen to study the influence of operating parameters. Two synthetic aluminosilicates (faujasite-Y and ZSM-5) were tested for adsorption and reactivity with ozone. The adsorption equilibrium measurement on both adsorbents showed that adsorption performance depends on temperature but is not sensitive to relative humidity, due to the hydrophobic properties of the materials. Adsorbed VOCs were oxidized at low temperature when ozonated flow was sent to the reactor. Regeneration of the fixed bed was achieved at the same time, releasing mainly CO(2) and H(2)O. Intermediates of oxidation, such as 2,3-butanedione and acetic acid, were identified, leading to incomplete mineralization. The influence of concentration and humidity are discussed. Four successive cycles were tested: after the first adsorption/ozonation cycle, the adsorption efficiency was not affected during subsequent cycles. These results show that the same sample of adsorbent can be used in the treatment process for a long time. Ozonation regeneration is a promising process for VOC removal. PMID:22925878

  8. Assessing the fate of biodegradable volatile organic contaminants in unsaturated soil filter systems

    NASA Astrophysics Data System (ADS)

    Thullner, Martin; de Biase, Cecilia; Hanzel, Joanna; Reger, Daniel; Wick, Lukas; Oswald, Sascha; van Afferden, Manfred; Schmidt, Axel; Reiche, Nils; Jechalke, Sven

    2010-05-01

    The assessment of contaminant biodegradation in the subsurface is challenged by various abiotic processes leading to a reduction of contaminant concentration without a destructive mass removal of the contaminant. In unsaturated porous media, this interplay of processes is further complicated by volatilization. Many organic contaminants are sufficiently volatile to allow for significant fluxes from the water phase into the soil air, which can eventually lead to an emission of contaminants into the atmosphere. Knowledge of the magnitude of these emissions is thus required to evaluate the efficiency of bioremediation in such porous media and to estimate potential risks due to these emissions. In the present study, vertical flow constructed wetlands were investigated at the pilot scale as part of the SAFIRA II project. The investigated wetland system is intermittently irrigated by contaminated groundwater containing the volatile compounds benzene and MTBE. Measured concentration at the in- and outflow of the system demonstrate a high mass removal rate, but the highly transient flow and transport processes in the system challenge the quantification of biodegradation and volatilization and their contribution to the observed mass removal. By a combination of conservative solute tracer tests, stable isotope fractionation and measurements of natural radon concentration is the treated groundwater is was possible to determine the contribution of biodegradation and volatilization to total mass removal. The results suggest that for the investigated volatile compounds biodegradation is the dominating mass removal process with volatilization contributing only to minor or negligible amounts. These results can be confirmed by reactive transport simulations and were further supported by laboratory studies showing that also gas phase gradients of volatile compounds can be affected by biodegradation suggesting the unsaturated zone to act as a biofilter for contaminants in the soil air.

  9. The effects of biotin deficiency on organic acid metabolism: increase in propionyl coenzyme A-related organic acids in biotin-deficient rats.

    PubMed

    Liu, Y Y; Shigematsu, Y; Nakai, A; Kikawa, Y; Saito, M; Fukui, T; Hayakawa, K; Oizumi, J; Sudo, M

    1993-11-01

    Volatile organic acid levels in plasma and tissues and nonvolatile organic acid levels in urine of biotin-deficient (BD) rats were measured and compared with other factors of biotin deficiency. Biotin levels and the activities of propionyl coenzyme A (CoA) carboxylase (PCC) in the livers of these rats were decreased, respectively, to 22% +/- 3% and 3.6% +/- 0.3% of the average values of pair-fed controls. Plasma concentrations of propionate were higher (15 to 223 micrograms/mL) than those of controls (5 to 7 micrograms/mL), whereas plasma levels of 3-methylcrotonate were only minimally increased as compared with those of controls. Concentrations of these volatile acids in the tissues were similarly increased, although those in brain showed less remarkable increases as compared with levels in other tissues. In the urine of BD rats, large amounts of organic acids derived from propionyl CoA, as well as those from 3-methylcrotonyl CoA, were excreted. Plasma propionate levels were not apparently related to the severity of clinical symptoms, biotin levels, or carboxylase activities, but were related to the amounts of urinary ketone bodies, lactate, and some of the organic acids derived from branched-chain amino acids, including those from propionyl CoA. PMID:8231832

  10. A global perspective on aerosol from low-volatility organic compounds

    NASA Astrophysics Data System (ADS)

    Pye, H. O. T.; Seinfeld, J. H.

    2010-02-01

    Organic aerosol from primary semivolatile and intermediate volatility compounds is estimated using a global chemical transport model. Semivolatile organic compound (SVOC, saturation concentrations between about 0.1 and 104 ?g/m3) oxidation is predicted to be a much larger global source of net aerosol production than oxidation of traditional parent hydrocarbons (terpenes, isoprene, and aromatics). Using a prescribed rate constant and reduction in volatility, the yield of aerosol (defined as the net mass of aerosol formed divided by the total mass of the parent hydrocarbon emitted) from SVOCs is predicted to be about 75% on a global, annually averaged basis. Intermediate volatility compound (IVOC, saturation concentrations between about 104 and 106 ?g/m3) emissions and oxidation are highly uncertain since they are not typically measured. The use of a naphthalene-like surrogate with different high-NOx and low-NOx parameterizations produces an aerosol yield of about 30% or roughly 5 Tg/yr of aerosol from IVOC oxidation on a global basis. Estimates of the total global organic aerosol source presented here range between 60 and 100 Tg/yr. This range reflects uncertainty in the parameters for SVOC volatility, SVOC oxidation, SVOC emissions, and IVOC emissions, as well as wet deposition. The highest estimates result if SVOC emissions are significantly underestimated (by more than a factor of 2) or if wet deposition of the gas-phase semivolatile species is less effective than previous estimates. Compared to a traditional non-volatile primary organic aerosol model without IVOCs, the global estimate of organic aerosol production is at most roughly 10% higher than previous studies. Additional information is needed to constrain the emissions and treatment of SVOCs and IVOCs, which have traditionally not been included in models. Comparisons to winter organic carbon observations over the US indicate that SVOC emissions are significantly underestimated by the traditional POA inventories. The degree to which IVOC emissions or other parameters are uncertain is unknown.

  11. On-line removal of volatile fatty acids from CELSS anaerobic bioreactor via nanofiltration

    NASA Technical Reports Server (NTRS)

    Colon, Guillermo

    1995-01-01

    The CELSS (controlled ecological life support system) resource recovery system, which is a waste processing system, uses aerobic and anaerobic bioreactors to recover plants nutrients and secondary foods from the inedible biomass. The anaerobic degradation of the inedible biomass by means of culture of rumen bacteria,generates organic compounds such as volatile fatty acids (acetic, propionic, butyric, VFA) and ammonia. The presence of VFA in the bioreactor medium at fairly low concentrations decreases the microbial population's metabolic reactions due to end-product inhibition. Technologies to remove VFA continuously from the bioreactor are of high interest. Several candidate technologies were analyzed, such as organic solvent liquid-liquid extraction, adsorption and/or ion exchange, dialysis, electrodialysis, and pressure driven membrane separation processes. The proposed technique for the on-line removal of VFA from the anaerobic bioreactor was a nanofiltration membrane recycle bioreactor. In order to establish the nanofiltration process performance variables before coupling it to the bioreactor, a series of experiments were carried out using a 10,000 MWCO tubular ceramic membrane module. The variables studied were the bioreactor slurry permeation characteristics, such as, the permeate flux, VFA and the nutrient removal rates as a function of applied transmembrane pressure, fluid recirculation velocity, suspended matter concentration, and process operating time. Results indicate that the permeate flux, VFA and nutrients removal rates are directly proportional to the fluid recirculation velocity in the range between 0.6 to 1.0 m/s, applied pressure when these are low than 1.5 bar, and inversely proportional to the total suspended solids concentration in the range between 23,466 to 34,880. At applied pressure higher than 1.5 bar the flux is not more linearly dependent due to concentration polarization and fouling effects over the membrange surface. It was also found that the permeate flux declines rapidly during the first 5 to 8 hours, and then levels off with a diminishing rate of flux decay.

  12. Factors influencing quantities of sugars and organic acids in blackcurrant concentrates

    Microsoft Academic Search

    Raymond K. Boccorh; Alistair Paterson; John R. Piggott

    1998-01-01

    Use of endogenous non-volatile flavour components, i.?e. sugars and organic acids, in fruit juice products is desirable.\\u000a A study of 133 blackcurrant concentrates from three seasons examined variation in sugars and acids arising from storage of\\u000a fruit at freezing or sub-ambient temperature, seasonal differences, geographical origin and choice of conventional thermal-evaporative\\u000a or freeze concentration technology. Compared with freeze concentrates, conventional

  13. HISTORIC EMISSIONS OF VOLATILE ORGANIC COMPOUNDS IN THE UNITED STATES FROM 1900 TO 1985

    EPA Science Inventory

    The report gives an estimate of historic emissions of volatile organic compounds (VOCs) for each state (and the District of Columbia) of the contiguous U.S. Annual emissions were estimated on the national level from 1960 to 1985. For 1940, 1950, and every fifth year from 1960 to ...

  14. Volatile Organic Compounds in Ground Water From Rural Private Wells, 1986 to 1999

    Microsoft Academic Search

    Michael J. Moran; Wayne W. Lapham; Barbara L. Rowe; John S. Zogorski

    2004-01-01

    The U.S. Geological Survey (USGS) collected or compiled data on volatile organic compounds (VOCs) in samples of untreated ground water from 1,926 rural private wells during 1986 to 1999. At least one VOC was detected in 12 percent of samples from rural private wells. Individual VOCs were not commonly detected with the seven most frequently detected compounds found in only

  15. Simplified sampling and analysis system for the determination of volatile organic compounds in combustion effluents

    Microsoft Academic Search

    R. H. James; R. E. Adams; L. D. Johnson

    1987-01-01

    The paper gives results of a study to provide a design for a simplified sampling system to support engineering projects for waste combustion requiring numerous semiroutine sampling tests. Sorbents and tandem-bed sorbent sampling tubes were evaluated to develop a rugged, compact collection system for medium-concentration levels of volatile organic compounds (VOCs). Development of the system and laboratory evaluation of the

  16. Performance evaluation materials for the analysis of volatile organic contaminants in soil: A preliminary assessment

    Microsoft Academic Search

    T. E. Lewis; B. A. Deason; C. L. Gerlach; D. W. Bottrell

    1990-01-01

    During an evaluation of field portable gas chromatographs (GC), site?specific performance evaluation materials (PEM) were prepared and used as quality control samples. Clean soils from two contaminated sites were spiked with various volatile organic compounds. The PEM were shipped to the field via air carrier and analyzed by GC. The PEM samples were also shipped back to the laboratory and

  17. Quantitative determination of volatile organic compounds in indoor dust using gas chromatography-UV spectrometry

    Microsoft Academic Search

    Anders Nilsson; Verner Lagesson; Carl-Gustaf Bornehag; Jan Sundell; Christer Tagesson

    2005-01-01

    A novel technique, gas chromatography-UV spectrometry (GC-UV), was used to quantify volatile organic compounds (VOCs) in settled dust from 389 residences in Sweden. The dust samples were thermally desorbed in an inert atmosphere and evaporated compounds were concentrated by solid phase micro extraction and separated by capillary GC. Eluting compounds were then detected, identified, and quantified using a diode array

  18. EMISSION OF VOLATILE ORGANIC COMPOUNDS FROM DRUM-MIX ASPHALT PLANTS

    EPA Science Inventory

    This research program was undertaken in order to develop a quantitative estimate of the emission of volatile organic compounds (VOCs) from drum-mix asphalt plants. The study was carried out by field sampling of five drum-mix plants under a variety of operating conditions. Include...

  19. BEHAVIOR AND DETERMINATION OF VOLATILE ORGANIC COMPOUNDS IN SOIL: A LITERATURE REVIEW

    EPA Science Inventory

    This report is a comprehensive literature review that presents and assesses research results that pertain to the problems and inconsistencies observed in the sampling and analysis of soil volatile organic compounds (VOC) by SW-846 method 5030 (purge and trap) for sample preparati...

  20. Characterization of volatile organic compounds and odorants associated with swine barn particulate matter

    Microsoft Academic Search

    Jacek A. Koziel; Lingshuang Cai; Yin-Cheung Lo; Steven J. Hoff

    Swine operations can affect air quality by emissions of odor, volatile organic compounds (VOCs) and other gases, and particulate matter (PM). Particulate matter has been proposed to be an important pathway for carrying odor. However, little is known about the odor-VOCs-PM interactions. In this research, continuous PM sampling was conducted simultaneously with three collocated TEOM analyzers inside a 1000-head swine

  1. Odor-causing volatile organic compounds in wastewater treatment plant units and sludge management areas

    Microsoft Academic Search

    Faruk Dincer; Aysen Muezzinoglu

    2008-01-01

    Odors due to malodorous gas and vapor emissions from units of Izmir Wastewater Treatment Plant (WWTP) were studied and evaluated with respect to chemical composition. Altogether 29 target compounds consisting of 4 different groups of chemicals were identified and quantified in the odorous gas samples from wastewater and sludges. Total volatile malodorous organic compounds (VMOC) consisted of reduced sulfur compounds

  2. EVALUATION OF THE FLUX CHAMBER METHOD FOR MEASURING VOLATILE ORGANIC EMISSIONS FROM SURFACE IMPOUNDMENTS

    EPA Science Inventory

    This research deals with the validation of the flux chamber method for measuring volatile organic emissions from liquid surfaces in treatment, storage and disposal facilities (TSDF). A simulated surface impoundment was constructed so that method precision and accuracy could be de...

  3. TEMPERATURE-DEPENDENT COLLECTION EFFICIENCY OF A CRYOGENIC TRAP FOR TRACE-LEVEL VOLATILE ORGANIC COMPOUNDS

    EPA Science Inventory

    Reduced temperature preconcentration of volatile organic compounds in a packed trap is examined experimentally as a function of trapping temperatures ranging from -180C to +100C. Trapped compounds are thermally desorbed into a capillary column-equipped gas chromatograph and quant...

  4. SUPERCRITICAL FLUID EXTRACTION OF SEMI-VOLATILE ORGANIC COMPOUNDS FROM PARTICLES

    EPA Science Inventory

    A nitrogen oxide flux chamber was modified to measure the flux of semi-volatile organic compounds (SVOCs). Part of the modification involved the development of methods to extract SVOCs from polyurethane foam (PUF), sand, and soil. Breakthroughs and extraction efficiencies were ...

  5. Volatile organic compound emissions from switchgrass cultivars used as biofuel crops

    Microsoft Academic Search

    A. S. D. Eller; K. Sekimoto; J. B. Gilman; W. C. Kuster; J. A. de Gouw; R. K. Monson; M. Graus; E. Crespo; C. Warneke; R. Fall

    2011-01-01

    Volatile organic compound (VOC) emission rates during the growth and simulated harvest phases were determined for switchgrass (Panicum virgatum) using laboratory chamber measurements. Switchgrass is a candidate for use in second-generation (cellulosic) biofuel production and the acreage dedicated to its growth in the USA has already increased during the past decade. We estimate that the yearly emissions from switchgrass plantations,

  6. THIN-FILM EVAPORATION AS A PRETREATMENT TECHNIQUE FOR REMOVING VOLATILE ORGANICS FROM PETROLEUM REFINERY WASTES

    EPA Science Inventory

    Oily wastes from petroleum refineries can result in air emissions during the land treatment of these wastes. A pilot-scale thin film evaporator (TFE) was used to remove volatile organics (VO) from refinery tank bottom sludge. Different TFE operating parameters were utilized to de...

  7. Chemical characterization of volatile organic compounds near the World Trade Center: Ambient concentrations and source apportionment

    Microsoft Academic Search

    David A. Olson; Gary A. Norris; Robert L. Seila; Matthew S. Landis; Alan F. Vette

    2007-01-01

    Concentrations of 53 volatile organic compounds (VOCs) are reported from four locations near the World Trade Center (WTC) (New York, USA) complex for canister samples collected from September 2001 through January 2002. Across the four sampling sites, mean concentrations ranged from 94.5 to 219?gm-3 for total VOCs. The highest mean concentrations for individual VOCs at any site were for ethane

  8. Controlling Strategies and Technologies of Volatile Organic Compounds Pollution in Interior Air of Cars

    Microsoft Academic Search

    Xiaokai Chen; Guoqiang Zhang; Hong Chen

    2010-01-01

    In interior air environment of cars, the mass concentrations of volatile organic compounds (VOC) are so high that human health is threatened. Their sources are analyzed and the controlling strategies and technologies are discussed. Reduce interior temperature, enhance vehicle ventilation, control interior materials, clean air-conditioning on time and use photo catalytic oxidation or adsorptive technology are the effective manners to

  9. FIELD EVALUATION OF VOLATILE ORGANIC COMPOUND REMOVAL EFFICIENCY FOR FULL-SCALE CARBON ADSORPTION SYSTEMS

    EPA Science Inventory

    Six full-scale, fixed-bed carbon adsorption systems were tested for vapor-phase volatile organic compound removal efficiency. Solvents used in the systems included methyl ethyl ketone, isopropyl acetate, tetrahydrofuran and toluene. One year after the first tests, repeat testing ...

  10. MODELING OF MULTICOMPONENT PERVAPORATION FOR REMOVAL OF VOLATILE ORGANIC COMPOUNDS FROM WATER

    EPA Science Inventory

    A resistance-in-series model was used to study the pervaporation of multiple volatile organic compounds (VOCs)-water mixtures. Permeation experiments were carried out for four membranes: poly(dimethylsiloxane) (PDMS), polyether-block-polyamides (PEBA), polyurethane (PUR) and sil...

  11. SEPARATION AND ISOLATION OF VOLATILE ORGANIC COMPOUNDS USING VACUUM DISTILLATION WITH GC/MS DETERMINATION

    EPA Science Inventory

    Vacuum distillation of water, soil, oil, and fish samples is presented as an alternative technique for determining volatile organic compounds (VOCs). Analyses of samples containing VOCs and non-VOCs at 50ppb concentrations were performed to evaluate method limitations. Analyte re...

  12. Internal Standards: A Source of Analytical Bias For Volatile Organic Analyte Determinations

    EPA Science Inventory

    The use of internal standards in the determination of volatile organic compounds as described in SW-846 Method 8260C introduces a potential for bias in results once the internal standards (ISTDs) are added to a sample for analysis. The bias is relative to the dissimilarity betw...

  13. RECONCILING URBAN VOC/NOX (VOLATILE ORGANIC COMPOUNDS/NOX) EMISSION INVENTORIES WITH AMBIENT CONCENTRATION DATA

    EPA Science Inventory

    A review of the current state of emission inventories of volatile organic compounds (VOC) and NOx data compiled for urban areas in the U.S. is presented. The study reveals great differences in the gross emission magnitudes when compared with corresponding ambient air concentratio...

  14. Abatement of volatile organic sulfur compounds in odorous emissions from the bio-industry.

    PubMed

    Smet, E; Van Langenhove, H

    1998-01-01

    Compounds of interest in this work are methanethiol (MeSH), dimethyl sulfide (Me2S), dimethyl polysulfides (Me2Sx) and carbon disulfide (CS2) since these volatiles have been identified as predominant odorants in the emission of a wide range of activities in the bio-industry (e.g. aerobic waste water treatment plants, composting plants, rendering plants). In these processes, the occurrence of volatile organic sulfur compounds is mainly related to the presence of anaerobic microsites with consecutive fermentation of sulfur containing organic material and/or to the breakdown of the latter due to thermal heating. Due to the chemical complexity of these low-concentrated waste gas streams and the high flow rates to be handled, mainly biotechnological techniques and scrubbers can be used to control the odour emission. When using biofilters or trickling filters, inoculation with specific microorganisms and pH-control strategies should be implemented to optimise the removal of volatile organic sulfur compounds. In scrubbers, chemical oxidation of the volatile organic sulfur compounds can be obtained by dosing hypochlorite, ozone or hydrogen peroxide to the scrubbing liquid. However, optimal operational conditions for each of these abatement techniques requires a further research in order to guarantee a long-term and efficient overall odour abatement. PMID:10022070

  15. FINAL REPORT: MEMBRANE-MEDIATED EXTRACTION AND BIODEGRADATION OF VOLATILE ORGANIC COMPOUNDS FROM AIR

    EPA Science Inventory

    The report describes feasibility tests of a two-step strategy for air pollution control applicable to exhaust air contaminated with volatile organic compounds (VOCs) from painting aircraft. In the first step, the VOC-contaminated air passes over coated, polypropylene, hollow-fibe...

  16. Development of the colorimetric sensor array for detection of explosives and volatile organic compounds in air

    NASA Astrophysics Data System (ADS)

    Kostesha, N. V.; Alstrøm, T. S.; Johnsen, C.; Nilesen, K. A.; Jeppesen, J. O.; Larsen, J.; Jakobsen, M. H.; Boisen, A.

    2010-04-01

    In the framework of the research project 'Xsense' at the Technical University of Denmark (DTU) we are developing a simple colorimetric sensor array which can be useful in detection of explosives like DNT and TNT, and identification of volatile organic compounds in the presence of water vapor in air. The technology is based on an array of chemo-responsive dyes immobilized on a solid support. Upon exposure to the analyte in suspicion the dye array changes color. Each chosen dye reacts chemo selectively with analytes of interest. A change in a color signature indicates the presence of unknown explosives and volatile organic compounds (VOCs). We are working towards the selection of dyes that undergo color changes in the presence of explosives and VOCs, as well as the development of an immobilization method for the molecules. Digital imaging of the dye array before and after exposure to the analytes creates a color difference map which gives a unique fingerprint for each explosive and volatile organic compound. Such sensing technology can be used to screen for relevant explosives in a complex background as well as to distinguish mixtures of volatile organic compounds distributed in gas phase. This sensor array is inexpensive, and can potentially be produced as single use disposable.

  17. Reactions of volatile organic compounds in the atmosphere: Ozone-alkene reactions

    Microsoft Academic Search

    Jill Denise Fenske

    2000-01-01

    Photochemical smog cannot form without sunlight, nitrogen oxides, and volatile organic compounds (VOC). This dissertation addresses several different aspects of VOC chemistry in the atmosphere. Aside from ambient levels of VOC outdoors, VOC are also present at moderate concentrations indoors. Many studies have measured indoor air concentrations of VOC, but only one considered the effects of human breath. The major

  18. Volatile organic compounds in snow in the Quebec-Windsor Corridor

    Microsoft Academic Search

    G. Kos; P. A. Ariya

    2010-01-01

    Volatile organic compounds (VOC) were determined in snow to investigate the role of the snowpack as an exchange medium for atmospherically active compounds of anthropogenic and biogenic origin. The major question was which VOC species occur in snow and how the species identity and selected concentrations are related to the sampling area and environmental conditions. Samples were collected using a

  19. VOC (VOLATILE ORGANIC COMPOUNDS) FUGITIVE EMISSION DATA - HIGH DENSITY POLYETHYLENE PROCESS UNIT

    EPA Science Inventory

    The report gives data from a 10-month study of volatile organic compound (VOC) fugitive emissions from a high density polyethylene process unit. It gives statistics on leak frequency, leak occurrence, and leak recurrence, with a leak defined as having a screening value equal to o...

  20. Volatile organic compound emissions from usaf wastewater treatment plants in ozone nonattainment areas. Master's thesis

    SciTech Connect

    Ouellette, B.A.

    1994-09-01

    In accordance with the 1990 Clean Air Act Amendments (CAAA), this research conducts an evaluation of the potential emission of volatile organic compounds (VOCs) from selected Air Force wastewater treatment plants. Using a conservative mass balance analysis and process specific simulation models, volatile organic emission estimates are calculated for four individual facilities--Edwards AFB, Luke AFB, McGuire AFB, and McClellan AFB--which represent a cross section of the current inventory of USAF wastewater plants in ozone nonattainment areas. From these calculations, maximum facility emissions are determined which represent the upper limit for the potential VOC emissions from these wastewater plants. Based on the calculated emission estimates, each selected wastewater facility is evaluated as a potential major stationary source of volatile organic emissions under both Title I of the 1990 CAAA and the plant's governing Clean Air Act state implementation plan. Next, the potential impact of the specific volatile organics being emitted is discussed in terms of their relative reactivity and individual contribution to tropospheric ozone formation. Finally, a relative comparison is made between the estimated VOC emissions for the selected wastewater facilities and the total VOC emissions for their respective host installations.

  1. Volatile organic compound concentrations and emission rates in new manufactured and site-built houses

    Microsoft Academic Search

    A. T. Hodgson; A. F. Rudd; D. Beal; S. Chandra

    1999-01-01

    Concentrations of 54 volatile organic compounds (VOCs) and ventilation rates were measured in four new manufactured houses over 2 - 9.5 months following installation and in seven new site- built houses 1 - 2 months after completion. The houses were in four projects located in hot- humid and mixed-humid climates. They were finished and operational, but unoccupied. Ventilation rates ranged

  2. TEST METHODS FOR THE DETERMINATION OF VOLATILE ORGANIC COMPOUNDS IN CONSUMER PRODUCTS

    EPA Science Inventory

    The paper discusses two test methods for determining volatile organic compounds (VOCs) in consumer products. he development of test methods for determining VOC emissions from consumer products has been identified by many states as the highest priority research activity in the con...

  3. A GLOBAL INVENTORY OF VOLATILE ORGANIC COMPOUND EMISSIONS FROM ANTHROPOGENIC SOURCES

    EPA Science Inventory

    As part of an effort to assess the potential impacts associated with global climate change, the U.S. Environmental Protection Agency's Office of Research and Development is supporting global atmospheric chemistry research by developing global scale estimates of volatile organic c...

  4. LEAF, BRANCH, STAND & LANDSCAPE SCALE MEASUREMENTS OF VOLATILE ORGANIC COMPOUND FLUXES FROM U.S. WOODLANDS

    EPA Science Inventory

    Natural volatile organic compounds (VOC) fluxes were measured in three U.S. woodlands in summer 1993. Fluxes from individual leaves and branches were estimated with enclosure techniques and used to initialize and evaluate VOC emission model estimates. Ambient measurements were us...

  5. NATURAL VOLATILE ORGANIC COMPOUND EMISSION RATE ESTIMATES FOR U.S. WOODLAND LANDSCAPES

    EPA Science Inventory

    Volatile organic compound (VOC) emission rate factors are estimated for 49 tree genera based on a review of foliar emission rate measurements. oliar VOC emissions are grouped into three categories: isoprene, monoterpenes and other VOC'S. ypical emission rates at a leaf temperatur...

  6. Heterogeneous Adsorption Characteristics of Volatile Organic Compounds (VOCs) on MCM?48

    Microsoft Academic Search

    W. G. Shim; J. W. Lee; H. Moon

    2006-01-01

    This work focuses on the fundamental studies of heterogeneous adsorption characteristics of mesoporous adsorbent. MCM?48 was synthesized to investigate the adsorption properties of eight different volatile organic compounds (benzene, cyclohexane, n?hexane, toluene, methanol, acetone, methyl ethyl ketone (MEK), and trichloroethylene (TCE)). The gravimetric method was used to measure the adsorption equilibrium amount. Several simple and reliable methods such as isosteric

  7. NON-POLAR VOLATILE ORGANIC COMPOUNDS IN WHOLE AIR SAMPLES FROM THE AUTOEX STUDIES

    EPA Science Inventory

    Air samples were captured in SUMMA polished stainless steel canisters and returned to the laboratory for analysis of trace level volatile organic compounds by gas chromatography - mass spectrometry. ampling was performed over 2-hour periods at various distances from heavily trave...

  8. Low temperature atmospheric pressure discharge plasma processing for volatile organic compounds

    Microsoft Academic Search

    T. Oda; A. Kumada; K. Tanaka; T. Takahashi; S. Masuda

    1995-01-01

    The 1,000 ppm VOCs (volatile organic compounds) decomposition performance of SPCP (Surfaced Discharge Induced Plasma Chemical Processing) was studied relating to various carrier gas effects, plasma exposing methods and others in order to understand the decomposition mechanisms. In any carrier gas, a direct SPCP can decompose every VOC tested. The efficient decomposing carrier gases are oxygen, air and nitrogen in

  9. Field Test to Demonstrate Real-Time In-Situ Detection of Volatile Organic Compounds

    E-print Network

    Ho, Cliff

    1 Field Test to Demonstrate Real-Time In-Situ Detection of Volatile Organic Compounds Hazmat Spill Center, Nevada Test Site September 19-25, 2001 Clifford K. Ho Sandia National Laboratories Albuquerque-filled 55- gallon drum at the Hazmat Spill Center at the Nevada Test Site. Background and Objectives Tens

  10. Patterns in volatile organic compound emissions along a savanna-rainforest gradient in central Africa

    Microsoft Academic Search

    L. F. Klinger; J. Greenberg; A. Guenther; G. Tyndall; P. Zimmerman; J.-M. Moutsamboté; D. Kenfack

    1998-01-01

    In temperate regions the chemistry of the lower troposphere is known to be significantly affected by biogenic volatile organic compounds (VOCs) emitted by plants. The chemistry of the lower troposphere over the tropics, however, is poorly understood, in part because of the considerable uncertainties in VOC emissions from tropical ecosystems. Present global VOC models predict that base emissions of isoprene

  11. The Indoor Volatile Organic Compounds (VOCs) Pollution Control Methods - A Case Study

    Microsoft Academic Search

    Lei Yuan; NanYang Yu

    2010-01-01

    An aim in study volatile organic compound (VOCs) emission is to improve indoor air quality. VOCs are the major indoor air pollutants, this paper introduced the types ,sources and characteristics of pollution caused by VOCs in indoor air, and effect of VOCs on human health were presented. The pollution from sources, adsorption technology and photocatalytic oxidation technology ect. In order

  12. Adsorbents for dioxins: A new technique for sorbent screening for low-volatile organics

    Microsoft Academic Search

    Ralph T. Yang; Richard Q. Long; Joel Padin; Akira Takahashi; Tomonori Takahashi

    1999-01-01

    Dioxins are generated in all waste incinerators, and activated carbon has been used since 1991 as the adsorbent. However, no equilibrium adsorption information is available because no experimental technique has been developed for measuring adsorption for such low-volatile organic compounds at the low concentrations that are of interest (i.e., parts per trillion to parts per billion levels). A new technique

  13. ALDEHYDE AND OTHER VOLATILE ORGANIC CHEMICAL EMISSIONS IN FOUR FEMA TEMPORARY HOUSING UNITS ? FINAL REPORT

    Microsoft Academic Search

    Olivia Salazar; Randy L. Maddalena; Marion Russell; Douglas P. Sullivan; Michael G. Apte

    2008-01-01

    Four unoccupied FEMA temporary housing units (THUs) were studied to assess their indoor emissions of volatile organic compounds including formaldehyde. Measurement of whole-THU VOC and aldehyde emission factors (mu g h-1 per m2 of floor area) for each of the four THUs were made at FEMA's Purvis MS staging yard using a mass balance approach. Measurements were made in the

  14. Effects of organic solutes properties on the volatilization processes from water solutions.

    PubMed

    Lee, Chung-Kung; Chao, Huan-Ping; Lee, Jiunn-Fwu

    2004-01-01

    Effects of organic solutes properties, including Henry's law constant (H), molecular weight (M), molar volume at normal boiling point (Vb), and solubility (S), on the usefulness of rate estimation by reference to a reference substance (i.e., reference substance concept) and on the evaporation rate were investigated by measuring the volatilization rate constant of organic solutes under different environmental conditions, including mixing and surfactants. It was found that if benzene was used as a reference substance, the ratio of the solute rate to that of benzene (F) becomes insensitive to water mixing, whether the solute possessed high or low Henry's law constant. In the presence of surfactants, however, the F value changes sharply as the solute solubility decreases. For benzene, toluene, ethylbenzene, and xylenes (BTEX), the F values are essentially constant irrespective of the presence of other chemicals (including organic compounds, surfactants, and salinity) and of the variation in temperature. On the other hand, the volatilization rates are closely related to molecular weight (solubility) in the existence of mixing (surfactants). Three different approaches, i.e., mass-transport theory, modified Knudsen equation, and reaction rate concept, were used to evaluate the dependence of solute volatilization rates on solute properties. It was concluded that the interaction between solute properties and environmental parameters might play a key role in the volatilization process of organic solutes under different environmental conditions. PMID:14675648

  15. Characterizing and mitigating emissions of volatile organic compounds from animal feeding operations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Volatile organic compounds (VOC) emitted from animal feeding operations negatively impact local and potentially regional air quality though the release of both odorous and ozone precursor molecules. Characterizing emissions of VOCs from AFOs is strongly influenced by both the method and location of ...

  16. DEVELOPMENT OF A SAMPLER FOR PARTICULATE-ASSOCIATED AND LOW VOLATILITY ORGANIC POLLUTANTS IN RESIDENTIAL AIR

    EPA Science Inventory

    The report describes the development of a sampler for particulate-associated and low volatility organic pollutants in residential air. The performance of the sampler inlet, which is compatible with the proposed PM-10 regulations for particulate sampling, is documented under a var...

  17. LONG-TERM STUDY OF VOLATILE ORGANIC COMPOUND RECOVERY FROM AMPULATED, DRY, FORTIFIED SOILS

    EPA Science Inventory

    Our objective was to evaluate the stability and extractability of volatile organic compound (VOCs) when fortified on dry soils and stored in sealed ampules. Two desiccator-dried soils were fortified with eight neat VOCs, benzene,toluene,ethylbenzene,o-xylene,1,1,1-trichloroethane...

  18. EXTRACTION METHODS FOR RECOVERY OF VOLATILE ORGANIC COMPOUNDS FROM FORTIFIED DRY SOILS

    EPA Science Inventory

    Recovery of 8 volatile organic compounds (VOCs) from dry soils, each fortified at 800 ng/g soil, was studied in relation to the extraction method and time of extraction. Extraction procedures studied on desiccator-dried soils were modifications of EPA low-and high-level purge-and...

  19. Control of volatile organic emissions from petroleum liquid storage in external floating roof tanks

    Microsoft Academic Search

    R. K. Burr; K. C. Brothers; J. G. Wright

    1978-01-01

    This report provides the necessary guidance for development of regulations limiting emissions of volatile organic compounds (VOC) from storage of petroleum liquids in external floating roof tanks. Reasonably available control technology (RACT) is defined in this document; cost analysis for RACT is included for evaluating the cost effectiveness of controlling external floating roof tank sources.

  20. Temporal variation, regional sources, and removal processes of volatile organic compounds in New England

    Microsoft Academic Search

    Rachel S. Russo

    2009-01-01

    This dissertation describes three research projects with the common objective of characterizing the influence of volatile organic compounds (VOCs) on air quality in New England using measurements made over multiple years (2002-2008) and from different sampling locations. The specific objectives include identifying sources (direct emission or secondary production), quantifying mixing ratios, and characterizing the chemical (i.e., oxidation, photolysis) and physical

  1. A novel laboratory system for determining fate of volatile organic compounds in planted systems

    Microsoft Academic Search

    B. J. Orchard; W. J. Doucette; J. K Chard; B. Bugbee

    2000-01-01

    Contradictory observations regarding the uptake and translocation of volatile organic compounds (VOCs) by plants have been reported, most notably for trichloroethylene (TCE). Experimental artifacts resulting from the use of semistatic or low-flow laboratory systems may account for part of the discrepancy. Innovative plant growth chambers are required to rigorously quantify the movement of VOCs through higher plants while maintaining a

  2. MODELING OF MULTICOMPONENT PERVAPORATION FOR REMOVAL OF VOLATILE ORGANIC COMPOUNDS FROM WATER

    EPA Science Inventory

    A resistance in series model was used to study the pervaporation of multiple volatile organic compounds (VOCs) water mixtures. ermeation experiments were carried out for four membranes and three VOCs. he membrane permeability were calculated in terms of the resistance in series m...

  3. Industrial waste-water volatile organic compound emissions. Background information for BACT\\/LAER determinations

    Microsoft Academic Search

    J. Elliott; S. Watkins

    1990-01-01

    The purpose of the Control Technology Center (CTC) is to provide technical information to States on estimating and controlling volatile organic compounds (VOC) emissions from the collection and treatment of industrial wastewaters for Best Available Control Technology (BACT) and Lowest Achievable Emission Rate (LAER) determinations. Technical guidance projects, focus on topics of national or regional interest that are identified through

  4. Ambient volatile organic compound (VOC) concentrations around a petrochemical complex and a petroleum refinery

    Microsoft Academic Search

    Eylem Cetin; Mustafa Odabasi; Remzi Seyfioglu

    2003-01-01

    Air samples were collected between September 2000 and September 2001 in Izmir, Turkey at three sampling sites located around a petrochemical complex and an oil refinery to measure ambient volatile organic compound (VOC) concentrations. VOC concentrations were 4–20-fold higher than those measured at a suburban site in Izmir, Turkey. Ethylene dichloride, a leaded gasoline additive used in petroleum refining and

  5. PERFORMANCE EVALUATION MATERIALS FOR THE ANALYSIS OF VOLATILE ORGANIC CONTAMINANTS IN SOILS: A PRELIMINARY ASSESSMENT

    EPA Science Inventory

    During an evaluation of field portable gas chromatographs (GC), site-specific performance evaluation materials (PEM) were prepared and used as quality control samples. lean soils from two contaminated sites were spiked with various volatile organic compounds. he PEM were shipped ...

  6. INHIBITORY EFFECTS OF VOLATILE ORGANIC COMPOUNDS ON NEURONAL NICOTINIC ACETYLCHOLINE RECEPTORS.

    EPA Science Inventory

    INHIBITORY EFFECTS OF VOLATILE ORGANIC COMPOUNDS ON NEURONAL NICOTINIC ACETYLCHOLINE RECEPTORS. A.S. Bale*; P.J. Bushnell; C.A. Meacham; T.J. Shafer Neurotoxicology Division, NHEERL, ORD, US Environmental Protection Agency, Research Triangle Park, NC, USA Toluene (TOL...

  7. A study on volatile organic sulfide causes of odors at Philadelphia's Northeast Water Pollution Control Plant

    Microsoft Academic Search

    Xianhao Cheng; Earl Peterkin; Gary A. Burlingame

    2005-01-01

    Volatile organic sulfide (VOS) causes of odors were studied at Philadelphia's Northeast Water Pollution Control Plant between September 11 and November 25, 2003. Results showed that dimethyl sulfide (DMS) dominated the VOS pool whenever VOS concentration rose above the background level (<50?g\\/L). Methanethiol was generally less than 10% of VOS and it was mainly found at sites with limited or

  8. VOLATILE ORGANIC COMPOUNDS AS BREATH BIOMARKERS FOR ACTIVE AND PASSIVE SMOKING

    EPA Science Inventory

    Real-time breath measurement technology was used to investigate the suitability of some volatile organic compounds (VOCs) to serve as breath biomarkers for active and passive smoking and to measure actual exposures and resulting breath concentrations for persons exposed to toba...

  9. APPLICABILITY OF PASSIVE MONITORING DEVICES TO MEASUREMENT OF VOLATILE ORGANIC CHEMICALS IN AMBIENT AIR

    EPA Science Inventory

    Commercial passive monitoring devices for volatile organic chemicals were evaluated to determine their potential application to ambient air concentrations (0.1 to 50 ppbv). A high-performance passive device was developed for short-term, low-level monitoring applications. The stai...

  10. COMPARISON OF EMISSION PROFILES FOR VOLATILE ORGANIC COMPOUNDS FROM COTTON AND POLYPROPYLENE-BASED TARP

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A high electric field, radio-frequency ion mobility analyzer (RF-IMS) was used as a small detector in gas chromatographic separations of mixtures of volatile organic compounds including alcohols, aldehydes, esters, ethers, pheromes, and other chemical attractants for insects. The detector was equip...

  11. VOLATILE ORGANIC COMPOUND EMISSION PROJECTION MODEL (VERSION 1.8). USER'S MANUAL

    EPA Science Inventory

    The report discusses a model that can be used to estimate future emissions of volatile organic compounds (VOCs) and costs of their control by applying growth factors, emission constraints, control cost functions, and capacity retirement rates to the base line estimates of VOC emi...

  12. Low-Level Detections of Halogenated Volatile Organic Compounds in Groundwater

    E-print Network

    Low-Level Detections of Halogenated Volatile Organic Compounds in Groundwater: Use in Vulnerability sources. Increasingly, there is a need to conduct assessments of the vulnerability of groundwater systems-capture detector GC-ECD and by gas chromatography with mass spectrometry GC-MS in 109 groundwater samples from five

  13. Housing Characteristics and Indoor Concentrations of Selected Volatile Organic Compounds (VOCs) in Quebec City, Canada

    Microsoft Academic Search

    Marie-Ève Héroux; Denis Gauvin; Nicolas L. Gilbert; Mireille Guay; Geneviève Dupuis; Michel Legris; Benoît Lévesque

    2008-01-01

    Concentrations of 26 volatile organic compounds (VOCs) were measured continuously for 7 days during winter in 96 homes in Quebec City, Canada. Characteristics of the houses and activities of the occupants were documented through detailed questionnaires filled out by one adult per household. VOCs were sampled using passive monitors and analyzed by gas chromatography-mass selective detector (GC-MSD). Results indicate contributions

  14. Cadaveric volatile organic compounds released by decaying pig carcasses ( Sus domesticus L.) in different biotopes

    Microsoft Academic Search

    J. Dekeirsschieter; F. J. Verheggen; M. Gohy; F. Hubrecht; L. Bourguignon; G. Lognay; E. Haubruge

    2009-01-01

    Forensic entomology uses pig carcasses to surrogate human decomposition and to investigate the entomofaunal colonization. Insects communicate with their environment through the use of chemical mediators, which in the case of necrophagous insects, may consist in the cadaveric volatile organic compounds (VOCs) released by the corpse under decomposition. Previous studies have focused on cadaveric VOCs released from human corpses. Nevertheless,

  15. SEPARATION AND ISOLATION OF VOLATILE ORGANIC COMPOUNDS USING VACUUM DISTILLATION WITH GS/MS DETERMINATION

    EPA Science Inventory

    The U.S. EPA's vacuum distillation of water, soil, oil, and fish samples is presented as an alternative technique for determining volatile organic compounds. nalysis of samples containing VOCs and non-VOCs at 50 ppb concentrations were performed to evaluate method limitations. na...

  16. Compositions of Volatile Organic Compounds Emitted from Melted Virgin and Waste Plastic Pellets

    Microsoft Academic Search

    Kyoko Yamashita; Naomichi Yamamoto; Atsushi Mizukoshi; Miyuki Noguchi; Yueyong Ni; Yukio Yanagisawa; Richard Hoffbeck; Yongping Li; Guohe Huang; James Schwab; John Spicer; Kenneth Demerjian; Mark Gibson; Judith Guernsey; Stephen Beauchamp; David Waugh; Mathew Heal; Jeffrey Brook; Robert Maher; Graham Gagnon; Johnny McPherson; Barbara Bryden; Richard Gould; Liming Zhou; Philip Hopke; Weixiang Zhao; Elisabeth Hawley; Neven Kresic; Alexandra Wright; Michael Kavanaugh; Pat Saathoff; Amit Gupta; Ted Stathopoulos; Louis Lazure; ABM Khan; Nigel Clark; Mridul Gautam; W. Wayne; Gregory Thompson; Donald Lyons; Yu-Ming Kuo; Yasuhiro Fukushima

    2009-01-01

    To characterize potential air pollution issues related to recycling facilities of waste plastics, volatile organic compounds (VOCs) emitted from melted virgin and waste plastics pellets were analyzed. In this study, laboratory experiments were performed to melt virgin and waste plastic pellets under various temperatures (150, 200, and 250 °C) and atmospheres (air and nitrogen [N2]). In the study presented here,

  17. EVALUATION OF INNOVATIVE LOW-VOLATILE ORGANIC COMPOUND (VOC) INDUSTRIAL MAINTENANCE (IM) COATINGS

    EPA Science Inventory

    The paper discusses a field evaluation of the feasibility of using alternative low-volatile organic compound (VOC) coatings to replace higher-VOC coatings. he evaluation includes chemical, performance, and outdoor exposure testing. he feasibility of five alternative coatings for ...

  18. CHARACTERIZATION OF EMISSIONS OF VOLATILE ORGANIC COMPOUNDS FROM INTERIOR ALKYD PAINT

    EPA Science Inventory

    Alkyd paint continues to be used indoors for application to wood trim, cabinet surfaces, and some kitchen and bathroom walls. Paint may represent a significant source of volatile organic compounds (VOCs) indoors depending on the frequency of use and amount of surface paint. The U...

  19. COMPARISON OF TWO FIELD SAMPLING PROCEDURES (EN CORE AND FIELD METHANOL EXTRACTION) FOR VOLATILE ORGANIC COMPOUNDS

    EPA Science Inventory

    In-situ Lasagna technology was recently evaluated at a contaminated site at Offutt Air Force Base. The site was contaminated with low levels (< 30 mg/kg) of volatile organic compounds (VOCs). Originally, researchers planned to use field methanol extraction for both pre- and pos...

  20. Predicting partitioning of volatile organic compounds from air into plant cuticular matrix by quantum chemical descriptors

    Microsoft Academic Search

    Chunlei Zhang; Liu Feng; Jie Wei

    2002-01-01

    Based on theoretical linear solvation energy relationship and quantum chemical descriptors computed by AM1 Hamiltonian, a\\u000a new model is developed to predict the partitioning of some volatile organic compounds between the plant cuticular matrix and\\u000a air.

  1. Source apportionment of exposure to toxic volatile organic compounds using positive matrix factorization

    Microsoft Academic Search

    MELISSA J ANDERSON; SHELLY L MILLER; JANA B MILFORD

    2001-01-01

    Data from the Total Exposure Assessment Methodology studies, conducted from 1980 to 1987 in New Jersey (NJ) and California (CA), and the 1990 California Indoor Exposure study were analyzed using positive matrix factorization, a receptor-oriented source apportionment model. Personal exposure and outdoor concentrations of 14 and 17 toxic volatile organic compounds (VOCs) were studied from the NJ and CA data,

  2. Modelling the oxidation of seventeen volatile organic compounds to track yields of CO and CO 2

    Microsoft Academic Search

    Aoife Grant; Alexander T. Archibald; Mike C. Cooke; Dudley E. Shallcross

    2010-01-01

    A box model simulating tropospheric conditions was used to trace the oxidation pathways of 17 volatile organic compounds (VOCs) covering saturated, olefinic, oxygenated and aromatic species. Yields of carbon monoxide (CO), carbon dioxide (CO2) and other oxidation products were calculated over the duration of the model simulation. Conversion factors to CO and CO2 were determined for individual VOCs at various

  3. Aluminium foams as structured supports for volatile organic compounds (VOCs) oxidation

    Microsoft Academic Search

    Oihane Sanz; F. Javier Echave; Maialen Sánchez; Antonio Monzón; Mario Montes

    2008-01-01

    In this work aluminium foams were studied as structured supports for the elimination of volatile organic compounds (VOCs, toluene). Foams of different pore density, 10, 20 and 40pores per inch (ppi), were used in an anodisation process to produce a very thin layer of alumina. This alumina layer was impregnated with the active phase, platinum, by wet impregnation. Anodisation process

  4. Multi-day ozone production potential of volatile organic compounds calculated with a tagging approach

    Microsoft Academic Search

    T. M. Butler; M. G. Lawrence; D. Taraborrelli; J. Lelieveld

    2011-01-01

    Calculation of the ozone production potential of Volatile Organic Compounds (VOC) has traditionally been performed using so-called incremental reactivity techniques, requiring multiple photochemical model runs in which the combined direct and indirect effects on ozone from slight perturbations to each VOC are investigated in turn. A new approach to this problem is presented here using an extensively tagged chemical mechanism,

  5. Partition of Volatile Organic Compounds in Activated Sludge and Wastewater

    Microsoft Academic Search

    Jun-Hong Lin; Ming-Shean Chou

    2006-01-01

    The Henry’s law constant is important in the gas-liquid mass transfer process. Apparent dimensionless Henry’s law constant, or the gas-liquid partition coefficient (K’H), for both hydrophilic (methanol, isopropyl alcohol, and acetone) and hydrophobic (toluene and p-xylene) organic compounds in deionized (DI) water, a wastewater with a maximum total dissolved organic carbon (DOC) content of 700 mg\\/L, and DI water mixed

  6. Characterization of the non-volatile organic compounds in the aerosols of Hong Kong— identification, abundance and origin

    NASA Astrophysics Data System (ADS)

    Zheng, M.; Wan, T. S. M.; Fang, M.; Wang, F.

    The non-volatile solvent-extractable organic compounds (lipids) of biogenic and anthropogenic origins were isolated from total suspended particulates (TSP) samples collected during the winter months of 1993 in Hong Kong. They were characterized and quantified according to the following classes: n-alkanes, polycychc aromatic hydrocarbons, n-alkanoic acids, n-alkanols, and biomarkers such as triterpanes. Flash column chromatography technique was used to effectively separate the PAH from the samples and a recovery of better than 90% was achieved. It was found that almost all samples contained anthropogenic contributions and the levels were relatively high compared to earlier studies carried out in China [Simoneit et al. (1991) Atmospheric Environment25A, 2111-2129]. The results from the six different sampling stations suggested that mobile combustion sources constituted 39-63% of all the non-volatile solvent-extractable organics. In addition, there is evidence that the contribution of emissions from kitchens is significant due to the characteristic Chinese stir-frying cooking process The six stations can be divided into three different categories: urban, rural and heavily influenced by traffic. The identification, abundance and source of these organic compounds are also discussed.

  7. Volatile organic compound emissions from Larrea tridentata (creosotebush)

    E-print Network

    Meskhidze, Nicholas

    of the interference of dimethyl sulfide PTR-MS concentration measurements by the hydrated acetaldehyde ion 3 of potential interference of acetaldehyde water clusters on the PTR-MS signal (m/z 63) for dimethyl sulfide. 1:acetaldehyde, m/z 47:ethanol, m/z 61:acetic acid) (Karl et al., 2004; Harley et al., 2007; Jardine et al., 2008

  8. Acute effect of erythromycin on metabolic transformations of volatile fatty acid mixture under anaerobic conditions.

    PubMed

    Cetecioglu, Z; Ince, B; Ince, O; Orhon, D

    2015-04-01

    The study explored the acute inhibitory impact of erythromycin on the methanogenic activity of acclimated biomass fed with a volatile fatty acid mixture and acetate alone. Parallel batch reactors were operated for six days, with increasing erythromycin dosing in the range of 1-1000 mg L(-1). Substrate removal was monitored by means of soluble COD and volatile fatty acid (VFA) measurements together with parallel observations on biogas and methane generation. The inhibitory impact was variable with the initial erythromycin dose: At lower doses, the VFA mixture was completely removed but partially utilized, leading to reduced biogas and methane generation, suggesting the analogy of uncompetitive inhibition. At higher doses, propionate utilization was totally impaired and butyrate removal was reduced, but acetate was still fully removed. Remaining VFAs were partly converted to new VFA compound through isomerization and polymerization reactions. High erythromycin doses induced total inactivation of microbial metabolism with negligible methane generation. PMID:25542637

  9. Adsorption of volatile organic compounds by metal–organic frameworks MIL101: Influence of molecular size and shape

    Microsoft Academic Search

    Kun Yang; Qian Sun; Feng Xue; Daohui Lin

    2011-01-01

    Adsorption of gaseous volatile organic compounds (VOCs) on metal–organic frameworks MIL-101, a novel porous adsorbent with extremely large Langmuir surface area of 5870m2\\/g and pore volume of 1.85cm3\\/g, and the influence of VOC molecular size and shape on adsorption were investigated in this study. We observed that MIL-101 is a potential superior adsorbent for the sorptive removal of VOCs including

  10. An Investigation of Fecal Volatile Organic Metabolites in Irritable Bowel Syndrome

    PubMed Central

    Ahmed, Iftikhar; Greenwood, Rosemary; Costello, Ben de Lacy; Ratcliffe, Norman M.; Probert, Chris S.

    2013-01-01

    Diagnosing irritable bowel syndrome (IBS) can be a challenge; many clinicians resort to invasive investigations in order to rule out other diseases and reassure their patients. Volatile organic metabolites (VOMs) are emitted from feces; understanding changes in the patterns of these VOMs could aid our understanding of the etiology of the disease and the development of biomarkers, which can assist in the diagnosis of IBS. We report the first comprehensive study of the fecal VOMs patterns in patients with diarrhea-predominant IBS (IBS-D), active Crohn's disease (CD), ulcerative colitis (UC) and healthy controls. 30 patients with IBS-D, 62 with CD, 48 with UC and 109 healthy controls were studied. Diagnosis of IBS-D was made using the Manning criteria and all patients with CD and UC met endoscopic, histologic and/or radiologic criteria. Fecal VOMs were extracted by solid phase microextraction (SPME) and analyzed by gas chromatography-mass spectrometry (GC-MS). 240 VOMs were identified. Univariate analysis showed that esters of short chain fatty acids, cyclohexanecarboxylic acid and its ester derivatives were associated with IBS-D (p<0.05), while aldehydes were more abundant in IBD (p<0.05). A predictive model, developed by multivariate analysis, separated IBS-D from active CD, UC and healthy controls with a sensitivity of 94%, 96% and 90%; and a specificity of 82%, 80% and 80% respectively (p<0.05). The understanding of the derivation of these VOMs may cast light on the etiology of IBS-D and IBD. These data show that fecal VOMs analyses could contribute to the diagnosis of IBS-D, for which there is no laboratory test, as well as IBD. PMID:23516449

  11. Distribution of volatile organic compounds in a New Jersey coastal plain aquifer system

    USGS Publications Warehouse

    Fusillo, T.V.; Hochreiter, J.J., Jr.; Lord, D.G.

    1985-01-01

    Samples for analysis of volatile organic compounds were collected from 315 wells in the Potomac-Raritan-Magothy aquifer system in southwestern New Jersey and a small adjacent area in Pennsylvania during 1980-82. Volatile organic compounds were detected in all three aquifer units of the Potomac-Raritan-Magoth aquifer system in the study area. Most of the contamination appears to be confined to the outcrop area at present. Low levels of contamination, however, were found downdip of the outcrop area in the upper and middle aquifers. Trichloroethylene, tetrachloroethylene, and benzene were the most frequently detected compounds. Differences in the areal distributions of light chlorinated hydrocarbons, such as trichloroethylene, and aromatic hydrocarbons, such as benzene, were noted and are probably due to differences in the uses of the compounds and the distribution patterns of potential contamination sources. The distribution patterns of volatile organic compounds differed greatly among the three aquifer units. The upper aquifer, which crops out mostly in less-developed areas, had the lowest percentage of wells with volatile organic compounds detected (10 percent of wells sampled). The concentrations in most wells in the upper aquifer which had detectable levels were less than 10 ??g/l. In the middle aquifer, which crops out beneath much of the urban and industrial area adjacent to the Delaware River, detectable levels of volatile organic compounds were found in 22 percent of wells sampled, and several wells contained concentrations above 100 ??g/l. The lower aquifer, which is confined beneath much of the outcrop area of the aquifer system, had the highest percentage of wells (28 percent) with detectable levels. This is probably due to (1) vertical leakage of contamination from the middle aquifer, and (2) the high percentage of wells tapping the lower aquifer in the most heavily developed areas of the outcrop.

  12. Determination of Volatile Organic Compounds in Indoor Air of Buildings in Nuclear Power Plants, Taiwan

    Microsoft Academic Search

    Ling-Ling Hsieh; Chih-Chung Chang; Usha Sree; Jiunn-Guang Lo

    2006-01-01

    This study investigates the composition and concentrations of volatile organic compounds (VOCs) in air-conditioned office\\u000a space and low-level waste (LLW) repository sites of nuclear power plants located in Taiwan. Air samples were collected in\\u000a the office space and technical rooms of administration buildings of the three nuclear power plants and in LLW repository site\\u000a using canisters. Thirty-six toxic organic compounds

  13. An Endophytic Phomopsis sp. Possessing Bioactivity and Fuel Potential with its Volatile Organic Compounds

    Microsoft Academic Search

    Sanjay K. Singh; Gary A. Strobel; Berk Knighton; Brad Geary; Joe Sears; David Ezra

    2011-01-01

    An unusual Phomopsis sp. was isolated as endophyte of Odontoglossum sp. (Orchidaceae), associated with a cloud forest in Northern Ecuador. This fungus produces a unique mixture of volatile\\u000a organic compounds (VOCs) including sabinene (a monoterpene with a peppery odor) only previously known from higher plants.\\u000a In addition, some of the other more abundant VOCs recorded by GC\\/MS in this organism

  14. Ground-Water Issue: Soil sampling and analysis for volatile organic compounds

    Microsoft Academic Search

    T. E. Lewis; A. B. Crockett; R. L. Siegrist; K. Zarrabi

    1991-01-01

    The Regional Superfund Ground Water Forum is a group of ground-water scientists that represents EPA's Regional Superfund Offices. The forum was organized to exchange up-to-date information related to groundwater remediation at Superfund sites. Sampling of soils for volatile organic compounds (VOCs) is an issue identified by the Ground Water Forum as a concern of Superfund decision makers. Concerns over data

  15. Removal of volatile organic components (VOCs) from water by pervaporation: separation improvement by Dean vortices

    Microsoft Academic Search

    S Schnabel; P Moulin; Q. T Nguyen; D Roizard; P Aptel

    1998-01-01

    Dense polydimethylsiloxane (PDMS) hollow-fibre membrane modules built in straight and coiled configurations were studied in pervaporation for volatile organic compounds (VOCs) removal. Two different aqueous organic mixtures, n-butanol–water and chloroform–water, were investigated to determine how the permeate fluxes are affected by the module geometry. Data with chloroform–water mixtures of 0.1 and 0.05wt% chloroform revealed that, in the laminar regime, coiled

  16. Effect of collection and handling practices on concentrations of volatile organic compounds detected in soil subsamples

    SciTech Connect

    Hewitt, A.D. [Army Cold Regions Research and Engineering Lab., Hanover, NH (United States)

    1996-12-31

    The losses of trichloroethylene from soil samples transferred to and from a storage bottle were evaluated by comparing values obtained using standard techniques with values obtained using a method that limits sample disruption, exposure, and volatilization losses from a subsample after a single transfer step. Results strongly suggest that volatile organic compounds (VOCs) are readily lost from contaminated soils when care is not taken to limit surface area exposure and ensure subsample isolation. For this site investigation and others using similar sample-handling protocols, VOC losses are most abundant during field collection and storage.

  17. 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

  18. Volatile metabolites.

    PubMed

    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

  19. Nanoparticles modified with multiple organic acids

    NASA Technical Reports Server (NTRS)

    Cook, Ronald Lee (Inventor); Luebben, Silvia DeVito (Inventor); Myers, Andrew William (Inventor); Smith, Bryan Matthew (Inventor); Elliott, Brian John (Inventor); Kreutzer, Cory (Inventor); Wilson, Carolina (Inventor); Meiser, Manfred (Inventor)

    2007-01-01

    Surface-modified nanoparticles of boehmite, and methods for preparing the same. Aluminum oxyhydroxide nanoparticles are surface modified by reaction with selected amounts of organic acids. In particular, the nanoparticle surface is modified by reactions with two or more different carboxylic acids, at least one of which is an organic carboxylic acid. The product is a surface modified boehmite nanoparticle that has an inorganic aluminum oxyhydroxide core, or part aluminum oxyhydroxide core and a surface-bonded organic shell. Organic carboxylic acids of this invention contain at least one carboxylic acid group and one carbon-hydrogen bond. One embodiment of this invention provides boehmite nanoparticles that have been surface modified with two or more acids one of which additional carries at least one reactive functional group. Another embodiment of this invention provides boehmite nanoparticles that have been surface modified with multiple acids one of which has molecular weight or average molecular weight greater than or equal to 500 Daltons. Yet, another embodiment of this invention provides boehmite nanoparticles that are surface modified with two or more acids one of which is hydrophobic in nature and has solubility in water of less than 15 by weight. The products of the methods of this invention have specific useful properties when used in mixture with liquids, as filler in solids, or as stand-alone entities.

  20. Scalable printed electronics: an organic decoder addressing ferroelectric non-volatile memory

    PubMed Central

    Ng, Tse Nga; Schwartz, David E.; Lavery, Leah L.; Whiting, Gregory L.; Russo, Beverly; Krusor, Brent; Veres, Janos; Bröms, Per; Herlogsson, Lars; Alam, Naveed; Hagel, Olle; Nilsson, Jakob; Karlsson, Christer

    2012-01-01

    Scalable circuits of organic logic and memory are realized using all-additive printing processes. A 3-bit organic complementary decoder is fabricated and used to read and write non-volatile, rewritable ferroelectric memory. The decoder-memory array is patterned by inkjet and gravure printing on flexible plastics. Simulation models for the organic transistors are developed, enabling circuit designs tolerant of the variations in printed devices. We explain the key design rules in fabrication of complex printed circuits and elucidate the performance requirements of materials and devices for reliable organic digital logic. PMID:22900143

  1. Scalable printed electronics: an organic decoder addressing ferroelectric non-volatile memory.

    PubMed

    Ng, Tse Nga; Schwartz, David E; Lavery, Leah L; Whiting, Gregory L; Russo, Beverly; Krusor, Brent; Veres, Janos; Bröms, Per; Herlogsson, Lars; Alam, Naveed; Hagel, Olle; Nilsson, Jakob; Karlsson, Christer

    2012-01-01

    Scalable circuits of organic logic and memory are realized using all-additive printing processes. A 3-bit organic complementary decoder is fabricated and used to read and write non-volatile, rewritable ferroelectric memory. The decoder-memory array is patterned by inkjet and gravure printing on flexible plastics. Simulation models for the organic transistors are developed, enabling circuit designs tolerant of the variations in printed devices. We explain the key design rules in fabrication of complex printed circuits and elucidate the performance requirements of materials and devices for reliable organic digital logic. PMID:22900143

  2. Degradation of C2-C15 volatile organic compounds in a landfill cover soil.

    PubMed

    Tassi, Franco; Montegrossi, Giordano; Vaselli, Orlando; Liccioli, Caterina; Moretti, Sandro; Nisi, Barbara

    2009-07-15

    The composition of non-methane volatile organic compounds (hereafter VOCs) in i) the cover soil, at depths of 30, 50 and 70 cm, and ii) gas recovery wells from Case Passerini landfill site, (Florence, Italy) was determined by GC-MS. The study, based on the analysis of interstitial gases sampled along vertical profiles within the cover soil, was aimed to investigate the VOC behaviour as biogas transits from a reducing to a relatively more oxidizing environment. A total of 48 and 63 different VOCs were identified in the soil and well gases, respectively. Aromatics represent the dominant group (71.5% of total VOC) in soil gases, followed by alkanes (6.8%), ketones (5.7%), organic acids (5.2%), aldehydes (3.0%), esters (2.6%), halogenated compounds (2.1%) and terpenes (1.3%). Cyclics, heterocyclics, S-bearing compounds and phenols are

  3. BIOLOGICAL RESPONSE TO VARIATION OF ACID-VOLATILE SULFIDES AND METALS IN FIELD-EXPOSED SPIKED SEDIMENTS

    EPA Science Inventory

    Vertical and temporal variations of acid-volatile sulfides (AVS) and simultaneously extracted metals (SEM) in sediment can control biological impacts of metals. To assess the significance of these variations in field sediments, sediments spiked with cadmium, copper, lead, nickel ...

  4. Measurement of volatile organic compounds emitted in libraries and archives: an inferential indicator of paper decay?

    PubMed Central

    2012-01-01

    Background A sampling campaign of indoor air was conducted to assess the typical concentration of indoor air pollutants in 8 National Libraries and Archives across the U.K. and Ireland. At each site, two locations were chosen that contained various objects in the collection (paper, parchment, microfilm, photographic material etc.) and one location was chosen to act as a sampling reference location (placed in a corridor or entrance hallway). Results Of the locations surveyed, no measurable levels of sulfur dioxide were detected and low formaldehyde vapour (< 18??g?m-3) was measured throughout. Acetic and formic acids were measured in all locations with, for the most part, higher acetic acid levels in areas with objects compared to reference locations. A large variety of volatile organic compounds (VOCs) was measured in all locations, in variable concentrations, however furfural was the only VOC to be identified consistently at higher concentration in locations with paper-based collections, compared to those locations without objects. To cross-reference the sampling data with VOCs emitted directly from books, further studies were conducted to assess emissions from paper using solid phase microextraction (SPME) fibres and a newly developed method of analysis; collection of VOCs onto a polydimethylsiloxane (PDMS) elastomer strip. Conclusions In this study acetic acid and furfural levels were consistently higher in concentration when measured in locations which contained paper-based items. It is therefore suggested that both acetic acid and furfural (possibly also trimethylbenzenes, ethyltoluene, decane and camphor) may be present in the indoor atmosphere as a result of cellulose degradation and together may act as an inferential non-invasive marker for the deterioration of paper. Direct VOC sampling was successfully achieved using SPME fibres and analytes found in the indoor air were also identified as emissive by-products from paper. Finally a new non-invasive, method of VOC collection using PDMS strips was shown to be an effective, economical and efficient way of examining VOC emissions directly from the pages of a book and confirmed that toluene, furfural, benzaldehyde, ethylhexanol, nonanal and decanal were the most concentrated VOCs emitted directly from paper measured in this study. PMID:22587759

  5. Organic acids in springtime wisconsin precipitation samples

    NASA Astrophysics Data System (ADS)

    Chapman, E. G.; Sklarew, D. S.; Flickinger, J. S.

    A short-term study on organic acids in precipitation was conducted from 15 March to 1 June 1984 at two sites on the Wisconsin Acid Deposition Monitoring Network. Aliquots of collected samples were fixed with tetrachloromercurate (TCM) and analyzed for low molecular weight organic anions via ion-exclusion chromatography (ICE). Unfixed aliquots were subjected to standard network inorganic analyses. Of the 31 samples collected, 30 contained detectable concentrations of formate and acetate ions, with concentrations ranging from < 0.43 to 56 ?mol ? -1 for the former and < 0.83 to 33 ?mol ? -1 for the latter. Propionate, oxalate and malonate ions were also detected in a number of samples. Statistical analysis of the combined organic and inorganic data set indicated that no significant differences existed between the concentrations of organic ions at the two sites; however, samples containing visible sediments had significantly greater concentrations than samples without sediments. Maximum contributions of the organic acids to precipitation-free acidity, calculated by assuming that the only sources of the measured formate and acetate were their respective acid forms, averaged 18.6% for samples with a pH ? 5.0. Formate and acetate concentrations were highly correlated. Correlations between organic and inorganic ions were weak; NH +4 and Ca 2+ generally exhibited the highest, though still weak, correlations. The study emphasizes the need for further, longer-term investigations to determine the role of low molecular weight organic compounds in precipitation chemistry.

  6. VOLATILE ORGANIC CHEMICALS IN 10 PUBLIC-ACCESS BUILDINGS

    EPA Science Inventory

    The U.S. EPA carried out studies of indoor air quality in 10 buildings. Qualitative analysis identified over 200 aromatics, halogens, esters, alcohols, phenols, ethers, ketones, aldehydes, and epoxides, in addition to several hundred aliphatic hydrocarbons. The total organic load...

  7. A study of volatile organic sulfur emissions causing urban odors

    Microsoft Academic Search

    Aysen Muezzinoglu

    2003-01-01

    Levels of hydrogen sulfide and sulfur containing organic compounds were studied in the air at the deltas of the polluted creeks in the city of Izmir, Turkey in summer 2001. High concentrations of these malodorous compounds were measured in the air samples. Presence of these compounds in the air was connected with the dark appearance and rising gas bubbles in

  8. REVERSE OSMOSIS TREATMENT TO CONTROL INORGANIC AND VOLATILE ORGANIC CONTAMINATION

    EPA Science Inventory

    Because of the versatility of reverse osmosis for removing a wide range of contaminants, U.S. EPA (Drinking Water Research Division) has been conducting laboratory and field studies to determine its effectiveness on specific inorganic and organic contaminants of concern to the wa...

  9. Systemin and jasmonic acid regulate constitutive and herbivore-induced systemic volatile emissions in tomato, Solanum lycopersicum.

    PubMed

    Degenhardt, David C; Refi-Hind, Sarah; Stratmann, Johannes W; Lincoln, David E

    2010-12-01

    Transgenic tomato (Solanum lycopersicum) plants that overexpress the Prosystemin gene (35S::PS) and plants with a mutation in the JA biosynthetic pathway (def1) are known to exhibit a constitutive or reduced wound response, respectively. Here it is demonstrated that several independent 35S::PS lines emit high levels of specific volatiles in addition to increased accumulation of proteinase inhibitors (PIs). Furthermore, the temporal dynamics of systemically induced volatile compounds including green-leaf volatiles, terpenes, and shikimic acid-derivatives from 35S::PS and def1 plants in response to herbivore wounding and treatment with jasmonic acid (JA) are described. Application of JA induced defense protein accumulation and volatile emissions in wild type plants, but did not further increase systemic volatile emissions from 35S::PS plants. Wounding by Manduca sexta larvae induced synthesis of defense proteins and emission of volatiles in wild type plants, but not in def1 plants. Application of jasmonic acid restored the local and systemic accumulation of defense proteins in def1, as well as enhanced herbivore-induced volatile emissions. These results provide strong support for the role of prosystemin- and JA-signaling in the regulation of volatile emissions in tomato plants. PMID:20970815

  10. 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. PMID:25771960

  11. Attraction of the gypsy moth to volatile organic compounds (VOCs) of damaged Dahurian larch.

    PubMed

    Li, Jing; Valimaki, Sanna; Shi, Juan; Zong, Shixiang; Luo, Youqing; Heliovaara, Kari

    2012-01-01

    Olfactory responses of the gypsy moth Lymantria dispar (L.) (Lepidoptera: Lymantriidae), a major defoliator of deciduous trees, were examined in Inner Mongolia, China. We studied whether the gypsy moth adults are attracted by the major volatile organic compounds (VOCs) of damaged Larix gmelinii (Dahurian larch) foliage and compared the attractiveness of the plant volatiles with that of the synthetic sex pheromone. Our results indicated that the VOCs of the Dahurian larch were effective in attracting gypsy moth males especially during the peak flight period. The VOCs also attracted moths significantly better than the sex pheromone of the moth. Our study is the first trial to show the responses of adult gypsy moths to volatile compounds emitted from a host plant. Electroantennogram responses of L. gmelinii volatiles on gypsy moths supported our field observations. A synergistic effect between host plant volatiles and sex pheromone was also obvious, and both can be jointly applied as a new attractant method or population management strategy of the gypsy moth. PMID:23016284

  12. Hydrogen peroxide enhances the oxidation of oxygenated volatile organic compounds on mineral dust particles: a case study of methacrolein.

    PubMed

    Zhao, Yue; Huang, Dao; Huang, Liubin; Chen, Zhongming

    2014-09-16

    Heterogeneous oxidation of oxygenated volatile organic compounds (OVOCs) serves as an important sink of OVOCs as well as a source of secondary organic material. However, the roles of gas phase oxidants in these reactions are poorly understood. In this work, we present the first laboratory study of the heterogeneous reactions of methacrolein (MACR) on various mineral dust particles in the presence of gaseous H2O2. It is found that the presence of gaseous H2O2 significantly promotes both the uptake and oxidation of MACR on kaolinite, ?-Al2O3, ?-Fe2O3, and TiO2, but not on CaCO3. The oxidation of MACR produces organic acids as its major low-molecular-weight product, whose yields are enhanced by a factor of 2-6 in the presence of H2O2. In addition, organic peroxides such as methyl hydroperoxide, peroxyformic acid, and peroxyacetic acid are only formed in the presence of H2O2, and the formation of methyl hydroperoxide indicates that MACR oxidation on the surface involves reaction with OH radicals. A probe reaction using salicylic acid verifies the production of OH radicals from H2O2 decomposition on kaolinite, ?-Al2O3, ?-Fe2O3, and TiO2, which rationalizes the enhanced MACR oxidation observed on these particles. The uptake coefficients of MACR on kaolinite, ?-Fe2O3, and TiO2 in the presence of H2O2 are on the order of 10(-5)-10(-4). Our results provide new insights into the formation and chemical evolution of organic species in the atmosphere. PMID:25111165

  13. Validation of thermodesorption method for analysis of semi-volatile organic compounds adsorbed on wafer surface.

    PubMed

    Hayeck, Nathalie; Gligorovski, Sasho; Poulet, Irène; Wortham, Henri

    2014-05-01

    To prevent the degradation of the device characteristics it is important to detect the organic contaminants adsorbed on the wafers. In this respect, a reliable qualitative and quantitative analytical method for analysis of semi-volatile organic compounds which can adsorb on wafer surfaces is of paramount importance. Here, we present a new analytical method based on Wafer Outgassing System (WOS) coupled to Automated Thermal Desorber-Gas chromatography-Mass spectrometry (ATD-GC-MS) to identify and quantify volatile and semi-volatile organic compounds from 6", 8" and 12" wafers. WOS technique allows the desorption of organic compounds from one side of the wafers. This method was tested on three important airborne contaminants in cleanroom i.e. tris-(2-chloroethyl) phosphate (TCEP), tris-(2-chloroisopropyl) phosphate (TCPP) and diethyl phthalate (DEP). In addition, we validated this method for the analysis and quantification of DEP, TCEP and TCPP and we estimated the backside organic contamination which may contribute to the front side of the contaminated wafers. We are demonstrating that WOS/ATD-GC-MS is a suitable and highly efficient technique for desorption and quantitative analysis of organophosphorous compounds and phthalate ester which could be found on the wafer surface. PMID:24720963

  14. Measurements of Low Volatility Organic Compounds (LVOCs) in Aircraft Engine Exhaust

    NASA Astrophysics Data System (ADS)

    Cross, E. S.; Hunter, J. F.; Carrasquillo, A. J.; Daumit, K. E.; Herndon, S. C.; Franklin, J. P.; Miake-Lye, R. C.; Jayne, J.; Worsnop, D. R.; Kroll, J. H.

    2011-12-01

    Gas phase low volatilty organic compounds (LVOCs) comprise an atmospherically important, largely unmeasured class of organic species in the atmosphere. LVOCs consist of intermediate volatility organic compounds (IVOCs; i.e. C13-C20 n-alkanes) and semivolatile organic compunds (SVOCs; i.e. C21-C32 n-alkanes). Atmospheric oxidation of gas phase LVOCs results in the formation of secondary organic aerosol (SOA) which in turn has direct implications for climate and human health. The rates and the chemical properties of LVOC emissions and oxidation products (in the gas phase and particle phase) are poorly characterized and not accurately parameterized in atmospheric chemistry models. This paper will provide an overview of experimental results obtained with a novel technique that provides a volatility-resolved, quantitative measure of LVOCs (and LVOC oxidation products) in the atmosphere. Results from the Alternative Aviation Fuels Experiment (AAFEX-II) conducted at the NASA Dryden Aircraft Operations Facility in April 2011 will be presented. The experiment was designed to characterize the gas phase and particulate emissions from the NASA DC-8 Aircraft as a function of engine power and fuel type. Differences in the desorption profile (i.e. volatility) and chemical characteristics of the LVOC emissions will be highlighted.

  15. A laboratory-formulated sediment incorporating synthetic acid-volatile sulfide

    SciTech Connect

    Gonzalez, A.M. [IT Corp., Knoxville, TN (United States). Biotechnology Applications Center

    1996-12-01

    The application of laboratory-formulated sediment (LFS) could be expanded if toxicologically significant characteristics of sediment other than particle-size distribution, organic carbon content, and pH could be manipulated. This report describes the preparation of a LFS containing synthetic acid-volatile sulfide (AVS) and shows its similarity to natural sediment AVS. Several formulations were evaluated with respect to toxicity to Hyalella azteca and chemical stability. Amphipod survival was highest (95%) in LFS formulations in which the molar iron(II)/sulfide ratio was near 1, although amphipod survival was > 80% in six of seven formulations with {le} 20% excess metal or sulfide. Synthetic AVS in the test system oxidized rapidly at the sediment surface, but AVS at depth was stable for > 30 d when isolated from air or aerated water. Oxidation-reduction potential measurements and AVS analysis of core slices revealed a vertical oxidation profile, apparently established and limited by oxygen diffusion. A formulation consisting of a 1:1 molar ratio of iron and sulfide (FeS) was evaluated with respect to complexation of copper, zinc, and nickel and to the corresponding reduction in toxicity using 10-d H. azteca toxicity texts. Amphipod mortality in metal-spiked LFS with metal/AVS molar ratios > 1 was high relative to controls. In contrast, amphipod survival in metal-spiked LFS with metal/AVS molar ratios < 1 was generally similar to amphipod survival in nonspiked LFS containing synthetic AVS. A few exceptions, where toxicity was noted when metal/AVS ratios were < 1, could be explained by high concentrations of dissolved iron, which was released by the metal + AVS displacement reaction. The LFS containing synthetic AVS appears to mimic natural sediment AVS and thus can provide consistent and controlled substrates suitable for investigating metal/sediment chemistry and toxicity and for developing realistic sediment quality criteria for metals.

  16. Acid Gas Emissions Measured by COSPEC, Volatile Trap, and Filter Pack at Volcán Villarrica, South Chile

    NASA Astrophysics Data System (ADS)

    Witter, J. B.; Kress, V. C.; Delmelle, P.; Hersum, T. G.

    2001-12-01

    Volcán Villarrica is a basaltic andesite stratovolcano 170 km SE of Temuco, Chile. Villarrica has been characterized by continuous degassing from a summit lava lake since 1985. We present new measurements of the flux of SO2, HCl, and HF from Villarrica using correlation spectrometry (COSPEC) combined with the method of volatile traps and filter packs. COSPEC measurements yielded an average SO2 flux of 460+/-260 tons/day SO2. This is greater than, but within error of, the 260+/-170 tons/day SO2 measured by us last year. We assume H2S emission is negligible. Volatile trap and filter pack measurements were made at the summit crater. To test for diffuse degassing on the flanks of the volcano, we conducted a soil CO2 flux survey. Using an accumulation chamber configured with a continuous infrared CO2 gas analyzer, we found diffuse degassing of CO2 to be undetectable. We assume flank degassing of other gases is similarly low. Four volatile traps (6N KOH solution in a plastic beaker) were deployed at the active crater on three occasions for periods ranging from 8 to 13 days. Acid gas species were absorbed into the alkaline solution and the relative concentrations of SO4, Cl, and F were obtained by ion chromatography. Volatile traps yielded an average SO2/HCl ratio of 5.9+/-1.2 and HCl/HF ratio of 4.1+/-0.7. This compares with an average SO2/HCl ratio of 9.3+/-2.6 and HCl/HF ratio of 3.0+/-0.4 obtained with volatile traps in the 2000 field season. Twenty-three gas measurements were made using filter packs during eight summit days. Using a small vacuum pump we filtered the gas through a series of three paper filters each impregnated with a saturated sodium bicarbonate solution. Total filtration time varied from 3 to 46.5 minutes. Filtration time was chosen so that nearly all of the acid gases were absorbed by the first two filters in the filter stack. Relative concentrations of the acid gas species (SO4, Cl, and F) absorbed onto the filter paper were obtained by ion chromatography. Measurements of the acid gas species with filter packs yielded an average SO2/HCl ratio of 4.5+/-0.7 and HCl/HF ratio of 7.8+/-1.6. The volatile trap method is based on the assumption that the proportions of acid species absorbed into the alkaline solution are the same as those in the volcanic gas. Simultaneous collection of gas data using volatile traps and filter packs allows for a comparison of the two methods and an evaluation of this assumption. Filter packs yielded lower average SO2/HCl ratios but higher average HCl/HF and SO2/HF ratios. These results imply that the KOH solution in the volatile traps may not absorb S-gases and Cl as readily as it does F. Using gas ratios from filter pack measurements, we calculate average HCl and HF fluxes from Villarrica's summit crater of 102+/-42 tons/day and 13+/-3 tons/day, respectively. These values may be higher if H2S emission is significant.

  17. Two-dimensional metal-organic framework with wide channels and responsive turn-on fluorescence for the chemical sensing of volatile organic compounds.

    PubMed

    Zhang, Mei; Feng, Guangxue; Song, Zhegang; Zhou, Yu-Peng; Chao, Hsiu-Yi; Yuan, Daqiang; Tan, Tristan T Y; Guo, Zhengang; Hu, Zhigang; Tang, Ben Zhong; Liu, Bin; Zhao, Dan

    2014-05-21

    We report a 2D layered metal-organic framework (MOF) with wide channels named NUS-1 and its activated analogue NUS-1a composed of Zn4O-like secondary building units and tetraphenylethene (TPE)-based ligand 4,4'-(2,2-diphenylethene-1,1-diyl)dibenzoic acid. Due to its special structure, NUS-1a exhibits unprecedented gas sorption behavior, glass-transition-like phase transition under cryogenic conditions, and responsive turn-on fluorescence to various volatile organic compounds. Our approach using angular ligand containing partially fixed TPE units paves a way toward highly porous MOFs with fluorescence turn-on response that will find wide applications in chemical sensing. PMID:24824627

  18. Effects of acetic acid, ethanol, and SO(2) on the removal of volatile acidity from acidic wines by two Saccharomyces cerevisiae commercial strains.

    PubMed

    Vilela-Moura, Alice; Schuller, Dorit; Mendes-Faia, Arlete; Côrte-Real, Manuela

    2010-07-01

    Herein, we report the influence of different combinations of initial concentration of acetic acid and ethanol on the removal of acetic acid from acidic wines by two commercial Saccharomyces cerevisiae strains S26 and S29. Both strains reduced the volatile acidity of an acidic wine (1.0 gl(-1) acetic acid and 11% (v/v) ethanol) by 78% and 48%, respectively. Acetic acid removal by strains S26 and S29 was associated with a decrease in ethanol concentration of 0.7 and 1.2% (v/v), respectively. Strain S26 revealed better removal efficiency due to its higher tolerance to stress factors imposed by acidic wines. Sulfur dioxide (SO(2)) in the concentration range 95-170 mg l(-1)inhibits the ability of both strains to reduce the volatile acidity of the acidic wine used under our experimental conditions. Therefore, deacidification should be carried out either in wines stabilized by filtration or in wines with SO(2)concentrations up to 70 mg l(-1). Deacidification of wines with the better performing strain S26 was associated with changes in the concentration of volatile compounds. The most pronounced increase was observed for isoamyl acetate (banana) and ethyl hexanoate (apple, pineapple), with an 18- and 25-fold increment, respectively, to values above the detection threshold. The acetaldehyde concentration of the deacidified wine was 2.3 times higher, and may have a detrimental effect on the wine aroma. Moreover, deacidification led to increased fatty acids concentration, but still within the range of values described for spontaneous fermentations, and with apparently no negative impact on the organoleptical properties. PMID:20390413

  19. A global perspective on aerosol from low-volatility organic compounds

    NASA Astrophysics Data System (ADS)

    Pye, H. O. T.; Seinfeld, J. H.

    2010-05-01

    Global production of organic aerosol from primary emissions of semivolatile (SVOCs) and intermediate (IVOCs) volatility organic compounds is estimated using the global chemical transport model, GEOS-Chem. SVOC oxidation is predicted to be a larger global source of net aerosol production than oxidation of traditional parent hydrocarbons (terpenes, isoprene, and aromatics). Using a prescribed rate constant and reduction in volatility for atmospheric oxidation, the yield of aerosol from SVOCs is predicted to be about 75% on a global, annually-averaged basis. For IVOCs, the use of a naphthalene-like surrogate with different high-NOx and low-NOx parameterizations produces a global aerosol yield of about 30%, or roughly 5 Tg/yr of aerosol. Estimates of the total global organic aerosol source presented here range between 60 and 100 Tg/yr. This range reflects uncertainty in the parameters for SVOC volatility, SVOC oxidation, SVOC emissions, and IVOC emissions, as well as wet deposition. The highest estimates result if SVOC emissions are significantly underestimated (by more than a factor of 2) or if wet deposition of the gas-phase semivolatile species is less effective than previous estimates. A significant increase in SVOC emissions, a reduction of the volatility of the SVOC emissions, or an increase in the enthalpy of vaporization of the organic aerosol all lead to an appreciable reduction of prediction/measurement discrepancy. In addition, if current primary organic aerosol (POA) inventories capture only about one-half of the SVOC emission and the Henrys Law coefficient for oxidized semivolatiles is on the order of 103 M/atm, a global estimate of OA production is not inconsistent with the top-down estimate of 140 Tg/yr by (Goldstein and Galbally, 2007). Additional information is needed to constrain the emissions and treatment of SVOCs and IVOCs, which have traditionally not been included in models.

  20. Influence of temperature on volatile fatty acid production and microbial community structure during anaerobic fermentation of microalgae.

    PubMed

    Cho, Hyun Uk; Kim, Young Mo; Choi, Yun-Nam; Kim, Hye Gyeong; Park, Jong Moon

    2015-09-01

    The objectives of this study were to investigate the effect of operating temperature on volatile fatty acids (VFAs) production from microalgal biomass, and to clarify the relationships between VFAs accumulation at different temperatures and the corresponding bacterial communities. The VFA yields were 0.10±0.017, 0.12±0.008, and 0.34±0.009g/g VS at 35, 45, and 55°C, respectively. The proportion of acetic acid decreased from 85.6% to 65.8% as operating temperature increased, whereas that of propionic acid increased from near 0% to 15.5% and that of iso-valeric acid remained relatively stable (10.2-11.2%). Bacterial communities at different operating temperatures consisted mostly of the phyla Proteobacteria, Bacteroidetes, and Firmicutes, which can degrade organic compounds effectively. Bacillus sp. was more predominant at 55°C than at mesophilic temperatures, suggesting that this microorganism contributed significantly to the higher hydrolysis rate and VFA yield at this operating temperature. PMID:25791331

  1. Volatile free fatty acids as ripening indicators for Serra da Estrela cheese.

    PubMed

    Tavaria, F K; Silva Ferreira, A C; Malcata, F Xavier

    2004-12-01

    Serra da Estrela cheese is an artisanal cheese manufactured from raw ewe's milk coagulated with Cynara cardunculus; it is highly appreciated for its unique flavor and bouquet. This research effort focused on a search for the molecules responsible for those organoleptic characteristics. Eighty cheeses manufactured in 4 dairies located in the Appelation d'Origine Protegee region of Serra da Estrela, Portugal, were thus assayed for volatiles, in an attempt to characterize their odorous profile. Cheeses were analyzed from the time of manufacture up to 180 d of ripening. The volatile fraction was assayed by solid phase microextraction-gas chromatography/mass spectroscopy, and several compounds belonging to different chemical groups (e.g., fatty acids, esters, carbonyl compounds, pyrazines, and sulfur compounds) were detected in that traditional cheese. Among these, free fatty acids (FFA) were quantitatively the dominant family present. Furthermore, sensory descriptors for the typical aroma of this cheese included acidic, sweaty, and sheepy-like. Acetic, isobutyric, and isovaleric acids increased in concentration during the ripening process up to 90 d, and remained constant thereafter. Preliminary sensory analysis was performed by addition of the major FFA to an unripened cheese matrix; results showed that they could successfully be used as ripening indicators for this cheese. Such key molecules may thus be used to monitor ripening, and hence find the optimal consumption time for this gourmet dairy product. PMID:15545367

  2. Laboratory investigations of the hydroxyl radical-initiated oxidation of atmospheric volatile organic compounds

    NASA Astrophysics Data System (ADS)

    Vimal, Deepali

    The hydroxyl radical (OH) is one of the most important oxidants in the atmosphere, because reaction with OH is the dominant atmospheric fate of most trace atmospheric species. OH is intimately involved in a complex non-linear photochemical pathway involving anthropogenic and biogenic emissions of volatile organic compounds (VOCs) and nitrogen oxides that are emitted from vehicular exhaust and industrial emissions. This chemistry generates secondary tropospheric ozone which is an important greenhouse gas as well as a component of photochemical smog. In addition, this chemistry leads to the formation of secondary organic aerosols in the atmosphere which have implications for public health and climate change. The focus of this dissertation is to improve our understanding of this complex chemistry by investigating the rate-limiting elementary reactions which are part of the OH-initiated oxidation of important VOCs. Experimental (discharge flow technique coupled with resonance fluorescence and laser induced fluorescence) and theoretical studies (Density Functional Theory computations) of the kinetics of three atmospheric VOCs, acetic acid, 1,3-butadiene and methyl ethyl ketone are discussed. The acetic acid and OH reaction has been thought to undergo a hydrogen-bonded complex mediated pathway instead of a direct one leading to faster rate constants at lower temperature. Our results for the experimental investigation between 263-373 K and pressures of 2-5 Torr for the gas phase reaction of acetic acid with OH confirm the complex mediated reaction mechanism and indicate that acetic acid can play an important role especially in the oxidative chemistry of upper troposphere. The 1,3-butadiene and OH reaction is thought to undergo electrophilicaddition by OH which could display a complex pressure dependence similar to isoprene and 232-butenol as noted earlier in this laboratory. However, our results for the kinetics of the reaction between 273-423 K and a pressure range of 1-6 Torr indicate a lack of pressure independence owing to a more efficient scavenging of the intermediate butadiene-OH peroxy radicals by oxygen. The reaction of methyl ethyl ketone and OH has relatively few kinetic investigations and its reaction mechanism is thought to be similar to that of acetone, mediated by a hydrogen bonded prereactive complex. Our kinetic investigations between 2-5 Torr and 263-388 K confirm the above mechanism but are contrary to earlier product studies that suggest that the preferential abstraction of an alpha-hydrogen from MEK by OH takes place. Instead, based on the results of our kinetic isotope effect we propose that the reaction proceeds via the abstraction of beta-hydrogen. In addition, results from measurements and model simulations of OH and HO2 radicals in photooxidation of isoprene in a photochemical reaction chamber at Purdue University are presented. Isoprene is one of the most important reactive biogenic VOCs in the atmosphere because it can contribute to regional ozone production as well secondary organic aerosol production. Measurements of OH, isoprene and its oxidation products in an environmental chamber are compared to model predictions using the Regional Atmospheric Chemistry Mechanism to test and validate current models of isoprene oxidation in the atmosphere.

  3. Selective sensing of volatile organic compounds using novel conducting polymer-metal nanoparticle hybrids

    NASA Astrophysics Data System (ADS)

    Vaddiraju, Sreeram; Gleason, Karen K.

    2010-03-01

    Conducting polymer-metal nanoparticle hybrids, fabricated by assembling metal nanoparticles on top of functionalized conducting polymer film surfaces using conjugated linker molecules, enable the selective sensing of volatile organic compounds (VOCs). In these conducting polymer-metal nanoparticle hybrids, selectivity is achieved by assembling different metals on the same conducting polymer film. This eliminates the need to develop either different polymers chemistries or device configurations for each specific analyte. In the hybrids, chemisorption of the analyte vapor induces charge redistribution in the metal nanoparticles and changes their work function. The conjugated linker molecule causes this change in the work function of the tethered nanoparticles to affect the electronic states in the underlying conducting polymer film. The result is an easily measurable change in the resistance of the hybrid structure. The fabrication of these sensing elements involved the covalent assembly of nickel (Ni) and palladium (Pd) metal nanoparticles on top of poly(3,4-ethylenedioxythiophene-co-thiophene-3-acetic acid), poly(EDOT-co-TAA), films using 4-aminothiophenol linker molecules. The change in resistance of hybrid Pd/poly(EDOT-co-TAA) and Ni/poly(EDOT-co-TAA) hybrid films to acetone and toluene, respectively, is observed to be in proportion to their concentrations. The projected detection limits are 2 and 10 ppm for toluene and acetone, respectively. A negligible response (resistance change) of the Pd/poly(EDOT-co-TAA) films to toluene exposure confirmed its selectivity for detecting acetone. Similarly, lack of response to acetone confirmed the selectivity of the Ni/poly(EDOT-co-TAA) stacks for detecting toluene. It is anticipated that the assembly of other metals such as Ag, Au and Cu on top of poly(EDOT-co-TAA) would provide selectivity for detecting and discriminating other VOCs.

  4. Annual cycle of volatile organic compound exchange between a boreal pine forest and the atmosphere

    NASA Astrophysics Data System (ADS)

    Rantala, P.; Aalto, J.; Taipale, R.; Ruuskanen, T. M.; Rinne, J.

    2015-06-01

    Long-term flux measurements of volatile organic compounds (VOC) over boreal forests are rare, although the forests are known to emit considerable amounts of VOCs into the atmosphere. Thus, we measured fluxes of several VOCs and oxygenated VOCs over a Scots pine dominated boreal forest semi-continuously between May 2010 and December 2013. The VOC profiles were obtained with a proton-transfer-reaction mass-spectrometry, and the fluxes were calculated using vertical concentration profiles and the surface layer profile method connected to the Monin-Obukhov similarity theory. In total fluxes that differed significantly from zero on a monthly basis were observed for 14 out 27 measured masses. Monoterpenes had the highest net emission in all seasons and statistically significant positive fluxes were detected from March until November. Other important compounds emitted were methanol, ethanol/formic acid, acetone and isoprene/MBO. Oxygenated VOCs showed also deposition fluxes that were statistically different from zero. Isoprene/methylbutenol and monoterpene fluxes followed well the traditional isoprene algorithm and the hybrid algorithm, respectively. Emission potentials of monoterpenes were largest in late spring and fall which was possibly driven by growth processes and decaying of soil litter, respectively. Conversely, largest emission potentials of isoprene/methylbutenol were found in July. Thus, we concluded that most of the emissions of m/z 69 at the site consisted of isoprene that originated from broadleaved trees. Methanol had deposition fluxes especially before sunrise. This can be connected to water films on surfaces. Based on this assumption, we were able to build an empirical algorithm for bi-directional methanol exchange that described both emission term and deposition term. Methanol emissions were highest in May and June and deposition level increased towards fall, probably as a result of increasing relative humidity levels leading to predominance of deposition.

  5. Single-carbon discrimination by selected peptides for individual detection of volatile organic compounds

    NASA Astrophysics Data System (ADS)

    Ju, Soomi; Lee, Ki-Young; Min, Sun-Joon; Yoo, Yong Kyoung; Hwang, Kyo Seon; Kim, Sang Kyung; Yi, Hyunjung

    2015-03-01

    Although volatile organic compounds (VOCs) are becoming increasingly recognized as harmful agents and potential biomarkers, selective detection of the organic targets remains a tremendous challenge. Among the materials being investigated for target recognition, peptides are attractive candidates because of their chemical robustness, divergence, and their homology to natural olfactory receptors. Using a combinatorial peptide library and either a graphitic surface or phenyl-terminated self-assembled monolayer as relevant target surfaces, we successfully selected three interesting peptides that differentiate a single carbon deviation among benzene and its analogues. The heterogeneity of the designed target surfaces provided peptides with varying affinity toward targeted molecules and generated a set of selective peptides that complemented each other. Microcantilever sensors conjugated with each peptide quantitated benzene, toluene and xylene to sub-ppm levels in real time. The selection of specific receptors for a group of volatile molecules will provide a strong foundation for general approach to individually monitoring VOCs.

  6. Measurement of surface emission flux rates for volatile organic compounds at Technical Area 54

    SciTech Connect

    Trujillo, V.; Morgenstern, M.; Krier, D. [Los Alamos National Lab., NM (United States); Gilkeson, R. [Weirich and Associates, Albuquerque, NM (United States)

    1998-06-01

    The survey described in this report was conducted to estimate the mass of volatile organic compounds venting to the atmosphere from active and inactive waste disposal sites at Technical Area 54. A large number of nonintrusive passive sample collection devices were placed on the ground surface for 72 hours to characterize an area of approximately 150 acres. Results provided an indication of the boundary location of the known volatile organic plume, plume constituents, and isolated high concentration areas. The data from this survey enhanced existing data from a limited number of monitor wells currently used for plume surveillance. Results indicate that the estimated mass emission to the atmosphere is orders of magnitude lower than what is considered a small flux rate at a spill site or a Resource Conservation and Recovery Act landfill and is far below the threshold limit established by the State of New Mexico as an air quality concern.

  7. [Emission characteristics and hazard assessment analysis of volatile organic compounds from chemical synthesis pharmaceutical industry].

    PubMed

    Li, Yan; Wang, Zhe-Ming; Song, Shuang; Xu, Zhi-Rong; Xu, Ming-Zhu; Xu, Wei-Li

    2014-10-01

    In this study, volatile organic compounds (VOCs) released from chemical synthesis pharmaceutical industry in Taizhou, Zhejiang province were analyzed quantitatively and qualitatively. The total volatile organic compounds (TVOCs) was in the range of 14.9-308.6 mg · m(-3). Evaluation models of ozone formation potentials (OFP) and health risk assessment were adopted to preliminarily assess the environmental impact and health risk of VOCs. The results showed that the values of OFP of VOCs were in the range of 3.1-315.1 mg · m(-3), based on the maximum incremental reactivity, the main principal contribution was toluene, tetrahydrofuran (THF), acetic ether etc. The non-carcinogenic risk and the carcinogen risk fell in the ranges of 9.48 x 10(-7)-4.98 x 10(-4) a(-1) and 3.17 x 10(-5)- 6.33 x 10(-3). The principal contribution of VOCs was benzene, formaldehyde and methylene chloride. PMID:25693367

  8. Single-carbon discrimination by selected peptides for individual detection of volatile organic compounds

    PubMed Central

    Ju, Soomi; Lee, Ki-Young; Min, Sun-Joon; Yoo, Yong Kyoung; Hwang, Kyo Seon; Kim, Sang Kyung; Yi, Hyunjung

    2015-01-01

    Although volatile organic compounds (VOCs) are becoming increasingly recognized as harmful agents and potential biomarkers, selective detection of the organic targets remains a tremendous challenge. Among the materials being investigated for target recognition, peptides are attractive candidates because of their chemical robustness, divergence, and their homology to natural olfactory receptors. Using a combinatorial peptide library and either a graphitic surface or phenyl-terminated self-assembled monolayer as relevant target surfaces, we successfully selected three interesting peptides that differentiate a single carbon deviation among benzene and its analogues. The heterogeneity of the designed target surfaces provided peptides with varying affinity toward targeted molecules and generated a set of selective peptides that complemented each other. Microcantilever sensors conjugated with each peptide quantitated benzene, toluene and xylene to sub-ppm levels in real time. The selection of specific receptors for a group of volatile molecules will provide a strong foundation for general approach to individually monitoring VOCs. PMID:25779765

  9. Detection of volatile organic compounds as biomarkers in breath analysis by different analytical techniques.

    PubMed

    Buszewski, Bogus?aw; Grzywinski, Damian; Ligor, Tomasz; Stacewicz, Tadeusz; Bielecki, Zygmunt; Wojtas, Jacek

    2013-09-01

    Breath is a rich mixture containing numerous volatile organic compounds at trace amounts (ppbv-pptv level) such as: hydrocarbons, alcohols, ketones, aldehydes, esters or heterocycles. The presence of some of them depends on health status. Therefore, breath analysis might be useful for clinical diagnostics, therapy monitoring and control of metabolic or biochemical cell cycle products. This Review presents an update on the latest developments in breath analysis applied to diagnosing different diseases with the help of high-quality equipment. Efforts were made to fully and accurately describe traditional and modern techniques used to determine the components of breath. The techniques were compared in terms of design, function and also detection limit of different volatile organic compounds. GC with different detectors, MS, optical sensor and laser spectroscopic detection techniques are also discussed. PMID:24053244

  10. Banding of urea increased ammonia volatilization in a dry acidic soil.

    PubMed

    Rochette, Philippe; Macdonald, J Douglas; Angers, Denis A; Chantigny, Martin H; Gasser, Marc-Olivier; Bertrand, Normand

    2009-01-01

    Volatilization of ammonia following application of urea contributes to smog formation and degradation of natural ecosystems. The objective of this study was to evaluate the impact of (i) incorporation and banding of urea and (ii) surface broadcast of slow-release urea types on NH(3) volatilization in a dry acidic soil. Volatilization was measured using wind tunnels for 25 d after standard urea (140 kg N ha(-1)) was broadcast, broadcast and incorporated (0-5 cm), or incorporated in shallow bands (3-5 cm) to a conventionally tilled silty loam soil. Urea supplemented with a urease inhibitor or coated with a polymer was also broadcast at the soil surface. Little N diffused out of the polymer-coated granules and ammonia losses were low (4% of applied N). Use of a urease inhibitor also resulted in a low NH(3) loss (5% of applied N) while maintaining soil mineral N at levels similar to plots where untreated urea was broadcast. The rate of hydrolysis of urea broadcast at the soil surface was slowed by the lack of moisture and NH(3) loss (9% applied N) was the lowest of all treatments with standard urea. Incorporation of broadcast urea increased emissions (16% applied N) by increasing urea hydrolysis relative to surface application. Furthermore, incorporation in band also increased emissions (27% applied N) due to a localized increase in soil pH from 6.0 to 8.7. We conclude that incorporating urea in bands in a dry acidic soil can increase NH(3) volatilization compared to broadcast application followed by incorporation. PMID:19465713

  11. Acid neutralizing capacity, alkalinity, and acid-base status of natural waters containing organic acids

    Microsoft Academic Search

    Harold F. Hemond

    1990-01-01

    The terms acid neutralizing capacity (ANC) and alkalinity (Alk) are extensively employed in the characterization of natural waters, including soft circumneutral or acidic waters. However, in the presence of organic acids, ANC measurements are inconsistent with many conceptual definitions of ANC or Alk and do not provide an adequate characterization of the acid-base chemistry of water. Knowledge of Gran ANC

  12. Recognition of volatile organic compounds using SnO 2 sensor array and pattern recognition analysis

    Microsoft Academic Search

    Dae-Sik Lee; Jong-Kyong Jung; Jun-Woo Lim; Jeung-Soo Huh; Duk-Dong Lee

    2001-01-01

    A sensor array with 10 sensors integrated on a substrate was developed to recognize various kinds and quantities of volatile organic compounds (VOCs), such as benzene, toluene, ethyl alcohol, methyl alcohol, and acetone. The sensor array consists of gas-sensing materials using SnO2 as the base material, plus a heating element based on a meandered platinum layer, all deposited on the

  13. Fabrication and characteristics of SnO 2 gas sensor array for volatile organic compounds recognition

    Microsoft Academic Search

    Dae-Sik Lee; Youn Tae Kim; Jeung-Soo Huh; Duk-Dong Lee

    2002-01-01

    Ten different gas sensors were integrated as an array on a substrate to identify various kinds and quantities of volatile organic compounds (VOCs), such as benzene, toluene, ethyl alcohol, methyl alcohol, and acetone. The sensor array consists of gas-sensing materials with SnO2 as the base material and a platinum heater and is fabricated using silk printing methods on an alumina

  14. Groundwater cleanup by in-situ sparging. II. Modeling of dissolved volatile organic compound removal

    SciTech Connect

    Wilson, D.J. (Vanderbilt Univ., Nashville, TN (United States))

    1992-10-01

    Simple steady-state and nonsteady-state models are developed for describing the removal of dissolved volatile organic compounds (VOCs) from aquifers by sparging techniques. A method is given for estimating the streamlines and transit times of water in a stagnant or nearly stagnant aquifer in the vicinity of a sparging well, and the resulting flow velocities are used to develop a model for the sparging of a VOC obeying Henry's law.

  15. Plasmochemical degradation of volatile organic compounds (VOC) in a capillary discharge plasma Reactor

    Microsoft Academic Search

    Agamemnon D. Koutsospyros; Shu-Min Yin; Christos Christodoulatos; Kurt Becker

    2005-01-01

    We report the results of parametric and kinetic studies of the plasmochemical degradation of volatile organic compounds (VOCs) present in respirable atmospheres using a nonthermal ambient-pressure plasma generated in a pin-to-plate capillary plasma electrode (CPE) discharge reactor. Parameters studied included the reactor volume, contaminant residence time, energy density, and influent contaminant concentration. A kinetic model was developed based on a

  16. GC × GC-MS HYPHENATED TECHNIQUES FOR THE ANALYSIS OF VOLATILE ORGANIC COMPOUNDS IN AIR

    Microsoft Academic Search

    Cecilia Arsene; Davide Vione; Nelu Grinberg; Romeo Iulian Olariu

    2011-01-01

    Comprehensive two-dimensional gas chromatography (GC × GC) and its direct applications to measurement of volatile and semivolatile organic compounds in air are reviewed and discussed. The paper includes a brief discussion of the instrumental set-up and theory for the comprehensive GC × GC hyphenated with different detection techniques. Several reviewed types of modulators demonstrate that the applications of comprehensive GC × GC are still under development,

  17. Analysis of Volatile Organic Compounds in a Controlled Environment: Ethylene Gas Measurement Studies on Radish

    NASA Technical Reports Server (NTRS)

    Kong, Suk Bin

    2001-01-01

    Volatile organic compound(VOC), ethylene gas, was characterized and quantified by GC/FID. 20-50 ppb levels were detected during the growth stages of radish. SPME could be a good analytical tool for the purpose. Low temperature trapping method using dry ice/diethyl ether and liquid nitrogen bath was recommended for the sampling process for GC/PID and GC/MS analysis.

  18. Real-time monitoring of volatile organic compounds using chemical ionization mass spectrometry

    DOEpatents

    Mowry, Curtis Dale (Albuquerque, NM); Thornberg, Steven Michael (Peralta, NM)

    1999-01-01

    A system for on-line quantitative monitoring of volatile organic compounds (VOCs) includes pressure reduction means for carrying a gaseous sample from a first location to a measuring input location maintained at a low pressure, the system utilizing active feedback to keep both the vapor flow and pressure to a chemical ionization mode mass spectrometer constant. A multiple input manifold for VOC and gas distribution permits a combination of calibration gases or samples to be applied to the spectrometer.

  19. Housewives’ exposure to volatile organic compounds relative to proximity to roadside service stations

    Microsoft Academic Search

    Wan-Kuen Jo; Kung-Cho Moon

    1999-01-01

    Residents in neighborhoods near a service station and\\/or major roadway would be expected to be exposed to elevated ambient volatile organic compound (VOC) levels compared to those further away from such source(s). We confirmed this and examined whether the anticipated high outdoor levels near a service station and\\/or major roadway outweighed the indoor levels as a factor for the exposure

  20. The speciation of volatile organic compounds (VOCs) from motorcycle engine exhaust at different driving modes

    Microsoft Academic Search

    Jiun-Horng Tsai; Hung-Lung Chiang; Yi-Chun Hsu; Hung-Cheng Weng; Chang-Yu Yang

    2003-01-01

    This study investigated the emissions of volatile organic compound (VOC) from motorcycle engine exhaust at different driving modes on a dynamometer. The speciations and the ozone formation potential of VOC samples also had been investigated by GC\\/MS and maximum increment reactivity (MIR), respectively. Both brand new and in-use motorcycles were tested in this study. The tested motorcycles include 2-stroke and

  1. A Study on Dynamic Volatile Organic Compound Emission Characterization of Water-Based Paints

    Microsoft Academic Search

    Yu-Min Chang; Wei-Hsing Hu; Wen-Bing Fang; Shiao-Shing Chen; Chang-Tang Chang; Hsiao-Wei Ching

    2011-01-01

    Volatile organic compounds (VOCs) emitted from surface coatings have caused growing public concern for air quality. Even the low-emitted VOC impact from water-based paints on indoor air quality in urban areas has caused concern. This paper presents experimental data using a mathematical model to simulate dynamic VOC emissions from water-based paints that is based on mass transfer and molecular diffusion

  2. Release and uptake of volatile inorganic and organic gases through the snowpack at Niwot Ridge, Colorado

    Microsoft Academic Search

    Detlev Helmig; Eric Apel; Donald Blake; Laurens Ganzeveld; Barry L. Lefer; Simone Meinardi; Aaron L. Swanson

    2009-01-01

    Whole air drawn from four heights within the high elevation (3,340 m asl), deep, winter snowpack at Niwot Ridge, Colorado,\\u000a were sampled into stainless steel canisters, and subsequently analyzed by gas chromatography for 51 volatile inorganic and\\u000a organic gases. Two adjacent plots with similar snow cover were sampled, one over bare soil and a second one from within a\\u000a snow-filled chamber

  3. Method for the Collection and Assay of Volatile Organic Compounds in Breath

    Microsoft Academic Search

    Michael Phillips

    1997-01-01

    Breath testing for volatile organic compounds (VOCs) provides an intrinsically safe method for investigating human metabolism. An improved breath-collecting apparatus (BCA) is described which was acceptable to patients, simple to use, highly sensitive, and free from chemical contamination. VOCs in 10.0 L alveolar breath and 10.0 L room air were collected onto adsorptive traps. Using automated instrumentation, VOCs were thermally

  4. Monitoring of polyaromatic hydrocarbons and volatile organic compounds in two major traffic tunnels in Seoul, Korea

    Microsoft Academic Search

    Ki-Hyun Kim; Ashish Anthwal; Chan Goo Park; Suk-Joo Jo; Young-Zoo Chae; Jin-A Park; Jong Heub Jung; Jong Ryeul Sohn; Jong-Min Oh

    2012-01-01

    To describe the fundamental aspects of air quality in tunnel environments, field campaigns were conducted to measure polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs), and some criteria pollutants from two tunnel sites of Nam San (NS) and Hong Ji (HJ) gates in Seoul, Korea. The total PAH values (ng m) for the NS tunnel (137.8±10.9) were notably higher than the

  5. Hybrid membranes and their use in volatile organic compound/air separations

    E-print Network

    Krohn, John Eric

    2001-01-01

    out that the membrane modifications resulted in a much smaller reduction in CsHs permeance than 15 reported in an earlier study. The difference bctwccn the two studies' graft-solution ODS concentrations was highlighted as potentially important...ff P . I 2SS: )l/ jflg~ ti;, + HYBRID MEMBRANES AND THEIR USE IN VOLATILE ORGANIC COMPOIJND/AIR SEPARATIONS A Thesis by JOHN ERIC KROHN Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment...

  6. Distributions and Source Apportionment of Ambient Volatile Organic Compounds in Beijing City, China

    Microsoft Academic Search

    YING LIU; MIN SHAO; JING ZHANG; LINLIN FU; SIHUA LU

    2005-01-01

    Ambient measurements of 108 volatile organic compounds (VOCs), including alkanes, alkenes, aromatics, and halogenated hydrocarbons, were conducted from 2002 to 2003 at six sites in Beijing city. The mean mass concentration of total VOCs was 132.6 ± 52.2 ?g\\/m, with alkanes, aromatics, and alkenes accounting for 35%, 22%, and 17%, respectively. The concentrations of most VOC species showed a seasonal

  7. Two-component aqueous epoxy binders free of volatile organic content (VOC)

    Microsoft Academic Search

    D. H Klein; K Jörg

    1997-01-01

    Water-borne two-pack coatings based on a novel epoxy resin emulsion, cross-linked with three different amine group containing curing agents, are discussed. The aqueous binders developed at the Research Laboratory at Dow Deutschland Inc. are free of volatile organic content. The epoxy resin emulsion has a low MFFT (minimum film formation temperature) and is hence capable of forming a continuous film

  8. Relationships between levels of volatile organic compounds in air and blood from the general population

    Microsoft Academic Search

    Y S Lin; P P Egeghy; S M Rappaport

    2008-01-01

    The relationships between levels of volatile organic compounds (VOCs) in blood and air have not been well characterized in the general population where exposure concentrations are generally at parts per billion levels. This study investigates relationships between the levels of nine VOCs, namely, benzene, chloroform, 1,4-dichlorobenzene, ethylbenzene, methyl tert-butyl ether (MTBE), tetrachloroethene, toluene, and m-\\/p- and o-xylene, in blood and

  9. Henry's law constants and micellar partitioning of volatile organic compounds in surfactant solutions

    Microsoft Academic Search

    Leland M. Vane; Eugene L. Giroux

    2000-01-01

    Partitioning of volatile organic compounds (VOCs) into surfactant micelles affects the apparent vapor-liquid equilibrium of VOCs in surfactant solutions. This partitioning will complicate removal of VOCs from surfactant solutions by standard separation processes. Headspace experiments were performed to quantify the effect of four anionic surfactants and one nonionic surfactant on the Henry's law constants of 1,1,1-trichloroethane, tirchloroethylene, toluene, and tetrachloroethylene

  10. Photoenhanced anaerobic digestion of organic acids

    SciTech Connect

    Weaver, P.F.

    1989-08-25

    A process is described for rapid conversion of organic acids and alcohols in anaerobic digesters into hydrogen and carbon dioxide, the optimal precursor substrates for production of methane. The process includes addition of photosynthetic bacteria to the digester and exposure of the bacteria to radiant energy (e.g., solar energy). The process also increases the pH stability of the digester to prevent failure of the digester. Preferred substrates for photosynthetic bacteria are the organic acid and alcohol waste products of fermentative bacteria. In mixed culture with methanogenic bacteria or in defined co-culture with non-aceticlastic methanogenic bacteria, photosynthetic bacteria are capable of facilitating the conversion of organic acids and alcohols into methane with low levels of light energy input. 8 figs.

  11. Photoenhanced anaerobic digestion of organic acids

    SciTech Connect

    Weaver, P.F.

    1990-04-24

    This patent describes a process for rapid conversion of organic acids and alcohols in anaerobic digesters into hydrogen and carbon dioxide, the optimal precursor substrates for production of methane. The process includes addition of photosynthetic bacteria to the digester and exposure of the bacteria to radiant energy (solar energy). The process also increases the pH stability of the digester to prevent failure of the digester. Preferred substrates for photosynthetic bacteria are the organic acid and alcohol waste products of fermentative bacteria. In mixed culture with methanogenic bacteria or in defined co-culture with non-aceticlastic methanogenic bacteria, photosynthetic bacteria are capable of facilitating the conversion or organic acids and alcohols into methane with low levels of light energy input.

  12. Photoenhanced anaerobic digestion of organic acids

    DOEpatents

    Weaver, Paul F. (Golden, CO)

    1990-01-01

    A process is described for rapid conversion of organic acids and alcohols anaerobic digesters into hydrogen and carbon dioxide, the optimal precursor substrates for production of methane. The process includes addition of photosynthetic bacteria to the digester and exposure of the bacteria to radiant energy (e.g., solar energy). The process also increases the pH stability of the digester to prevent failure of the digester. Preferred substrates for photosynthetic bacteria are the organic acid and alcohol waste products of fermentative bacteria. In mixed culture with methanogenic bacteria or in defined co-culture with non-aceticlastic methanogenic bacteria, photosynthetic bacteria are capable of facilitating the conversion or organic acids and alcohols into methane with low levels of light energy input.

  13. Volatile and sensory profile of organic red wines produced by different selected autochthonous and commercial Saccharomyces cerevisiae strains.

    PubMed

    Callejon, R M; Clavijo, A; Ortigueira, P; Troncoso, A M; Paneque, P; Morales, M L

    2010-02-15

    Organic wines were produced at pilot scale to select the best autochthonous and commercial yeast strains to obtain wines with high organoleptic qualities. We tested the behaviour of five S. cerevisiae yeast strains and determined their volatile composition and organoleptic characteristics by sensory analysis. A total of 51 volatile compounds were quantified in the wines produced. The concentration of most of the volatile compounds was significantly influenced depending on which yeast strain was inoculated. The differences observed in the volatile composition of the wines appear to be quantitative rather than qualitative. In general, acetals were the most abundant group of volatile compounds in all the samples studied, followed by alcohols without ethanol. The highest contents of volatile compounds were found in two of the wines produced by autochthonous yeast strains. The results obtained in the sensory analysis suggest that autochthonous yeast produced wines of higher organoleptic quality because this sample gave the highest value for the general impression attribute. PMID:20103145

  14. Oxidation of Volatile Organic Compounds on Al 2O 3, Pd\\/Al 2O 3, and PdO\\/Al 2O 3Catalysts

    Microsoft Academic Search

    Eric M Cordi; John L Falconer

    1996-01-01

    Temperature-programmed desorption (TPD) and oxidation (TPO) were used to study the decomposition and oxidation of methanol, ethanol, acetaldehyde, formic acid, and acetic acid on Al2O3, Pd\\/Al2O3, and PdO\\/Al2O3catalysts. The oxidation and decomposition rates were much higher on Pd\\/Al2O3than on Al2O3, even though the volatile organic compounds (VOCs) were adsorbed on the Al2O3support in both cases. The VOCs surface-diffused to Pd

  15. Detection of volatile organic compounds indicative of human presence in the air.

    PubMed

    Kwak, Jae; Geier, Brian A; Fan, Maomian; Gogate, Sanjay A; Rinehardt, Sage A; Watts, Brandy S; Grigsby, Claude C; Ott, Darrin K

    2015-07-01

    Volatile organic compounds were collected and analyzed from a variety of indoor and outdoor air samples to test whether human-derived compounds can be readily detected in the air and if they can be associated with human occupancy or presence. Compounds were captured with thermal desorption tubes and then analyzed by gas chromatography with mass spectrometry. Isoprene, a major volatile organic compound in exhaled breath, was shown to be the best indicator of human presence. Acetone, another major breath-borne compound, was higher in unoccupied or minimally occupied areas than in human-occupied areas, indicating that its majority may be derived from exogenous sources. The association of endogenous skin-derived compounds with human occupancy was not significant. In contrast, numerous compounds that are found in foods and consumer products were detected at elevated levels in the occupied areas. Our results revealed that isoprene and many exogenous volatile organic compounds consumed by humans are emitted at levels sufficient for detection in the air, which may be indicative of human presence. PMID:25944350

  16. Air monitoring for volatile organic compounds at the Pilot Plant Complex, Aberdeen Proving Ground, Maryland

    SciTech Connect

    Schneider, J.F.; O`Neill, H.J.; Raphaelian, L.A.; Tomczyk, N.A.; Sytsma, L.F.; Cohut, V.J.; Cobo, H.A.; O`Reilly, D.P.; Zimmerman, R.E.

    1995-03-01

    The US Army`s Aberdeen Proving Ground has been a test site for a variety of munitions, including chemical warfare agents (CWA). The Pilot Plant Complex (PPC) at Aberdeen was the site of development, manufacture, storage, and disposal of CWA. Deterioration of the buildings and violations of environmental laws led to closure of the complex in 1986. Since that time, all equipment, piping, and conduit in the buildings have been removed. The buildings have been declared free of surface CWA contamination as a result of air sampling using the military system. However, no air sampling has been done to determine if other hazardous volatile organic compounds are present in the PPC, although a wide range of toxic and/or hazardous materials other than CWA was used in the PPC. The assumption has been that the air in the PPC is not hazardous. The purpose of this air-monitoring study was to screen the indoor air in the PPC to confirm the assumption that the air does not contain volatile organic contaminants at levels that would endanger persons in the buildings. A secondary purpose was to identify any potential sources of volatile organic contaminants that need to be monitored in subsequent sampling efforts.

  17. Soil Samplers: New Techniques for Subsurface Sampling for Volatile Organic Compounds

    SciTech Connect

    Susan Sorini; John Schabron; Joseph Rovani; Mark Sanderson

    2009-03-31

    Soil sampling techniques for volatile organic analysis must be designed to minimize loss of volatile organic compounds (VOCs) from the soil that is being sampled. Preventing VOC loss from soil cores that are collected from the subsurface and brought to the surface for subsampling is often difficult. Subsurface bulk sample retrieval systems are designed to obtain intact cylindrical cores of soil ranging anywhere from one to four inches in diameter, and one to several feet in length. The current technique that is used to subsample these soil cores for VOC analysis is to expose a horizontal section of the soil core to the atmosphere; screen the exposed soil using a photoionization detector (PID) or other appropriate device to locate contamination in the soil core; and use a hand-operated coring tool to collect samples from the exposed soil for analysis. Because the soil core can be exposed to the atmosphere for a considerable length of time during screening and sample collection, the current sub-sampling technique provides opportunity for VOCs to be lost from the soil. This report describes three alternative techniques from the current technique for screening and collecting soil samples from subsurface soil cores for VOC analysis and field testing that has been done to evaluate the techniques. Based on the results of the field testing, ASTM D4547, Standard Guide for Sampling Waste and Soils for Volatile Organic Compounds, was revised to include information about the new techniques.

  18. Similar PAH Fate in Anaerobic Digesters Inoculated with Three Microbial Communities Accumulating Either Volatile Fatty Acids or Methane

    PubMed Central

    Braun, Florence; Hamelin, Jérôme; Bonnafous, Anaïs; Delgenès, Nadine; Steyer, Jean-Philippe; Patureau, Dominique

    2015-01-01

    Urban sludge produced on wastewater treatment plants are often contaminated by organic pollutants such as polycyclic aromatic hydrocarbons (PAH). Their removal under methanogenic conditions was already reported, but the factors influencing this removal remain unclear. Here, we determined the influence of microbial communities on PAH removal under controlled physico-chemical conditions. Twelve mesophilic anaerobic digesters were inoculated with three microbial communities extracted from ecosystems with contrasting pollution histories: a PAH contaminated soil, a PCB contaminated sediment and a low contaminated anaerobic sludge. These anaerobic digesters were operated during 100 days in continuous mode. A sterilised activated sludge, spiked with 13 PAH at concentrations usually encountered in full-scale wastewater treatment plants, was used as substrate. The dry matter and volatile solid degradation, the biogas production rate and composition, the volatile fatty acids (VFA) production and the PAH removals were monitored. Bacterial and archaeal communities were compared in abundance (qPCR), in community structure (SSCP fingerprinting) and in dominant microbial species (454-pyrosequencing). The bioreactors inoculated with the community extracted from low contaminated anaerobic sludge showed the greater methane production. The PAH removals ranged from 10 % to 30 %, respectively, for high and low molecular weight PAH, whatever the inoculums tested, and were highly correlated with the dry matter and volatile solid removals. The microbial community structure and diversity differed with the inoculum source; this difference was maintained after the 100 days of digestion. However, the PAH removal was not correlated to these diverse structures and diversities. We hence obtained three functional stable consortia with two contrasted metabolic activities, and three different pictures of microbial diversity, but similar PAH and matter removals. These results confirm that PAH removal depends on the molecule type and on the solid matter removal. But, as PAH elimination is similar whether the solid substrate is degraded into VFA or into methane, it seems that the fermentative communities are responsible for their elimination. PMID:25874750

  19. Tracing the link between plant volatile organic compound emissions and CO2 fluxes and by stable isotopes

    NASA Astrophysics Data System (ADS)

    Werner, Christiane; Wegener, Frederik; Jardine, Kolby

    2015-04-01

    The vegetation exerts a large influence on the atmosphere through the emission of volatile organic compounds (VOCs) and the emission and uptake of the greenhouse gas CO2. Despite the enormous importance, processes controlling plant carbon allocation into primary and secondary metabolism, such as photosynthetic carbon uptake, respiratory CO2 emission and VOC synthesis, remains unclear. Moreover, vegetation-atmosphere CO2 exchange is associated with a large isotopic imprint due to photosynthetic carbon isotope discrimination and 13C-fractionation during respiratory CO2 release1. The latter has been proposed to be related to carbon partitioning in the metabolic branching points of the respiratory pathways and secondary metabolism, which are linked via a number of interfaces including the central metabolite pyruvate. Notably, it is a known substrate in a large array of secondary pathways leading to the biosynthesis of many volatile organic compounds (VOCs), such as volatile isoprenoids, oxygenated VOCs, aromatics, fatty acid oxidation products, which can be emitted by plants. Here we investigate the linkage between VOC emissions, CO2 fluxes and associated isotope effects based on simultaneous real-time measurements of stable carbon isotope composition of branch respired CO2 (CRDS) and VOC fluxes (PTR-MS). We utilized positionally specific 13C-labeled pyruvate branch feeding experiments in the mediterranean shrub (Halimium halimifolium) to trace the partitioning of C1, C2, and C3 carbon atoms of pyruvate into VOCs versus CO2 emissions in the light and in the dark. In the light, we found high emission rates of a large array of VOC including volatile isoprenoids, oxygenated VOCs, green leaf volatiles, aromatics, sulfides, and nitrogen containing VOCs. These observations suggest that in the light, H. halimifolium dedicates a high carbon flux through secondary biosynthetic pathways including the pyruvate dehydrogenase bypass, mevalonic acid, MEP/DOXP, shikimic acid, and fatty acid pathways. Moreover, we found that high VOC emissions were closely related to 13CO2 decarboxylation from pyruvate-1-13C in the light, while mitochondrial respiration mas markedly down-regulated. Moreover, we found that in the dark, VOC emissions dramatically declined while respiration was stimulated with 13CO2 emissions under pyruvate-1-13C exceeding those under pyruvate-2-13C and pyruvate-2,3-13C during light-dark transitions. Our observations suggest VOC emissions are associated with significant pyruvate C1 decarboxylation. Moreover, the data suggests that light fundamentally controls the partitioning of assimilated carbon in leaves by regulating the competition for pyruvate between secondary biosynthetic reactions (e.g. VOC production) and mitochondrial respiration. Our investigation provides novel tool to better understand the mechanistic links between primary and secondary carbon metabolism in plants with important implications for a better understanding biosphere-atmosphere exchange of CO2 and VOCs. References 1. Werner C. & Gessler A. (2011) Diel variations in the carbon isotope composition of respired CO2 and associated carbon sources: a review of dynamics and mechanisms. Biogeosciences 8, 2437-2459 2. Jardine K, Wegener F, Abrell L, vonHaren J, Werner C (2014) Phytogenic biosynthesis and emission of methyl acetate. PCE 37, 414-424.

  20. Separation of boric acid from PWR waste by volatilization during evaporation

    SciTech Connect

    Bruggeman, A.; Braet, J.; Smaers, F.; De Regge, P. [SCK CEN Mol (Belgium)

    1997-01-01

    SCK{circ}CEN has developed a process to separate boric acid during and/or after evaporation of the liquid waste from pressurized light-water reactors. The key goal is to achieve higher waste volume reduction factors, while maintaining low activity discharge limits. An additional goal is to obtain purified boric acid for recycling. The process is based on the volatility of boric acid in steam. The liquid waste is treated in a semicontinuous evaporator, which operates preferentially at a higher temperature than the present evaporators. The stream loaded with boric acid is fed to a column for fractional condensation with partial reflux. In this way, one obtains a highly concentrated waste that contains all the radioactive and chemical impurities and little boron, a concentrated boric acid solution which can be reused, as well as a highly decontaminated effluent without boron. In case replacement or adaptation of existing evaporators is less practical, one can adapt the process for the treatment of evaporator concentrates. After having been intensively tested at SCK{circ}CEN, the process has recently been demonstrated in a small pilot installation and with realistic liquid waste, at the nuclear power station in Doel, Belgium. The results corresponded to the theoretical predictions. After a transitional period, the boron concentration in the evaporator no longer increased and consequently did not limit the achievable waste volume reduction factor. The boric acid was recovered from the steam and during a supplementary treatment additional boric acid from the waste concentrate was recovered.

  1. Emission rates of selected volatile organic compounds from skin of healthy volunteers

    PubMed Central

    Mochalski, Pawe?; King, Julian; Unterkofler, Karl; Hinterhuber, Hartmann; Amann, Anton

    2014-01-01

    Gas chromatography with mass spectrometric detection (GC–MS) coupled with solid phase micro-extraction as pre-concentration method (SPME) was applied to identify and quantify volatile organic compounds (VOCs) emitted by human skin. A total of 64 C4-C10 compounds were quantified in skin emanation of 31 healthy volunteers. Amongst them aldehydes and hydrocarbons were the predominant chemical families with eighteen and seventeen species, respectively. Apart from these, there were eight ketones, six heterocyclic compounds, six terpenes, four esters, two alcohols, two volatile sulphur compounds, and one nitrile. The observed median emission rates ranged from 0.55 to 4790 fmol cm?2 min?1. Within this set of analytes three volatiles; acetone, 6-methyl-5-hepten-2-one, and acetaldehyde exhibited especially high emission rates exceeding 100 fmol cm?2 min?1. Thirty-three volatiles were highly present in skin emanation with incidence rates over 80%. These species can be considered as potential markers of human presence, which could be used for early location of entrapped victims during Urban Search and Rescue Operations (USaR). PMID:24768920

  2. Volatile organic compounds produced by the phytopathogenic bacterium Xanthomonas campestris pv. vesicatoria 85-10

    PubMed Central

    Weise, Teresa; Kai, Marco; Gummesson, Anja; Troeger, Armin; von Reuß, Stephan; Piepenborn, Silvia; Kosterka, Francine; Sklorz, Martin; Zimmermann, Ralf; Francke, Wittko

    2012-01-01

    Summary Xanthomonas campestris is a phytopathogenic bacterium and causes many diseases of agricultural relevance. Volatiles were shown to be important in inter- and intraorganismic attraction and defense reactions. Recently it became apparent that also bacteria emit a plethora of volatiles, which influence other organisms such as invertebrates, plants and fungi. As a first step to study volatile-based bacterial–plant interactions, the emission profile of Xanthomonas c. pv. vesicatoria 85-10 was determined by using GC/MS and PTR–MS techniques. More than 50 compounds were emitted by this species, the majority comprising ketones and methylketones. The structure of the dominant compound, 10-methylundecan-2-one, was assigned on the basis of its analytical data, obtained by GC/MS and verified by comparison of these data with those of a synthetic reference sample. Application of commercially available decan-2-one, undecan-2-one, dodecan-2-one, and the newly synthesized 10-methylundecan-2-one in bi-partite Petri dish bioassays revealed growth promotions in low quantities (0.01 to 10 ?mol), whereas decan-2-one at 100 ?mol caused growth inhibitions of the fungus Rhizoctonia solani. Volatile emission profiles of the bacteria were different for growth on media (nutrient broth) with or without glucose. PMID:22563356

  3. Blood and breath profiles of volatile organic compounds in patients with end-stage renal disease

    PubMed Central

    2014-01-01

    Background Monitoring of volatile organic compounds (VOCs) in exhaled breath shows great potential as a non-invasive method for assessing hemodialysis efficiency. In this work we aim at identifying and quantifying of a wide range of VOCs characterizing uremic breath and blood, with a particular focus on species responding to the dialysis treatment. Methods Gas chromatography with mass spectrometric detection coupled with solid-phase microextraction as pre-concentration method. Results A total of 60 VOCs were reliably identified and quantified in blood and breath of CKD patients. Excluding contaminants, six compounds (isoprene, dimethyl sulfide, methyl propyl sulfide, allyl methyl sulfide, thiophene and benzene) changed their blood and breath levels during the hemodialysis treatment. Conclusions Uremic breath and blood patterns were found to be notably affected by the contaminants from the extracorporeal circuits and hospital room air. Consequently, patient exposure to a wide spectrum of volatile species (hydrocarbons, aldehydes, ketones, aromatics, heterocyclic compounds) is expected during hemodialysis. Whereas highly volatile pollutants were relatively quickly removed from blood by exhalation, more soluble ones were retained and contributed to the uremic syndrome. At least two of the species observed (cyclohexanone and 2-propenal) are uremic toxins. Perhaps other volatile substances reported within this study may be toxic and have negative impact on human body functions. Further studies are required to investigate if VOCs responding to HD treatment could be used as markers for monitoring hemodialysis efficiency. PMID:24607025

  4. Potential contribution of semi-volatile and intermediate volatility primary organic compounds to secondary organic aerosol in the Mexico City region

    NASA Astrophysics Data System (ADS)

    Hodzic, A.; Jimenez, J. L.; Madronich, S.; Canagaratna, M. R.; Decarlo, P. F.; Kleinman, L.; Fast, J.

    2010-01-01

    It has been established that observed local and regional levels of secondary organic aerosols (SOA) in polluted areas cannot be explained by the oxidation and partitioning of anthropogenic and biogenic VOC precursors, at least using current mechanisms and parameterizations. In this study, the 3-D regional air quality model CHIMERE is applied to quantify the contribution to SOA formation of recently identified semi-volatile and intermediate volatility organic vapors (S/IVOC) in and around Mexico City for the MILAGRO field experiment during March 2006. The model has been updated to include explicitly the volatility distribution of primary organic aerosols (POA), their gas-particle partitioning and the gas-phase oxidation of the vapors. Two recently proposed parameterizations, those of Robinson et al. (2007) ("ROB") and Grieshop et al. (2009) ("GRI") are compared and evaluated against surface and aircraft measurements. The 3-D model results are assessed by comparing with the concentrations of OA components from Positive Matrix Factorization of Aerosol Mass Spectrometer (AMS) data, and for the first time also with oxygen-to-carbon ratios derived from high-resolution AMS measurements. The results show a substantial enhancement in predicted SOA concentrations (3-6 times) with respect to the previously published base case without S/IVOCs (Hodzic et al., 2009), both within and downwind of the city leading to much reduced discrepancies with the total OA measurements. The predicted anthropogenic POA levels are found to agree within 20% with the observed HOA concentrations for both the ROB and GRI simulations, consistent with the interpretation of the emissions inventory by previous studies. The impact of biomass burning POA within the city is underestimated in comparison to the AMS BBOA, presumably due to insufficient nighttime smoldering emissions. Model improvements in OA predictions are associated with the better-captured SOA magnitude and diurnal variability. The predicted production from anthropogenic and biomass burning S/IVOC represents 40-60% of the total SOA at the surface during the day and is somewhat larger than that from aromatics, especially at the T1 site at the edge of the city. The SOA production from the continued multi-generation S/IVOC oxidation products continues actively downwind. Similar to aircraft observations, the predicted OA/?CO ratio for the ROB case increases from 20-30 ?g sm-3 ppm-1 up to 60-70 ?g sm-3 ppm-1 between a fresh and 1-day aged air mass, while the GRI case produces a 30-40% higher OA growth than observed. The predicted average O/C ratio of total OA for the ROB case is 0.16 at T0, substantially below observed value of 0.5. A much better agreement for O/C ratios and temporal variability (R2=0.63) is achieved with the updated GRI treatment. Both treatments show a deficiency in regard to POA evolution with a tendency to over-evaporate POA upon dilution of the urban plume suggesting that atmospheric HOA may be less volatile than assumed in these parameterizations. This study highlights the important potential role of S/IVOC chemistry in the SOA budget in this region, and highlights the need for improvements in current parameterizations. We note that our simulations did not include other proposed pathways of SOA formation such as formation from very volatile species like glyoxal, which can also contribute SOA mass and especially increase the O/C ratio.

  5. Potential contribution of semi-volatile and intermediate volatility primary organic compounds to secondary organic aerosol in the Mexico City region

    SciTech Connect

    Hodzic, A.; Kleinman, L.; Jimenez, J. L.; Madronich, S.; Canagaratna, M. R.; DeCarlo, P. F.; Fast, J.

    2010-03-01

    It has been established that observed local and regional levels of secondary organic aerosols (SOA) in polluted areas cannot be explained by the oxidation and partitioning of anthropogenic and biogenic VOC precursors, at least using current mechanisms and parameterizations. In this study, the 3-D regional air quality model CHIMERE is applied to quantify the contribution to SOA formation of recently identified semi-volatile and intermediate volatility organic vapors (S/IVOC) in and around Mexico City for the MILAGRO field experiment during March 2006. The model has been updated to include explicitly the volatility distribution of primary organic aerosols (POA), their gas-particle partitioning and the gas-phase oxidation of the vapors. Two recently proposed parameterizations, those of Robinson et al. (2007) ('ROB') and Grieshop et al. (2009) ('GRI') are compared and evaluated against surface and aircraft measurements. The 3-D model results are assessed by comparing with the concentrations of OA components from Positive Matrix Factorization of Aerosol Mass Spectrometer (AMS) data, and for the first time also with oxygen-to-carbon ratios derived from high-resolution AMS measurements. The results show a substantial enhancement in predicted SOA concentrations (3–6 times) with respect to the previously published base case without S/IVOCs (Hodzic et al., 2009), both within and downwind of the city leading to much reduced discrepancies with the total OA measurements. The predicted anthropogenic POA levels are found to agree within 20% with the observed HOA concentrations for both the ROB and GRI simulations, consistent with the interpretation of the emissions inventory by previous studies. The impact of biomass burning POA within the city is underestimated in comparison to the AMS BBOA, presumably due to insufficient nighttime smoldering emissions. Model improvements in OA predictions are associated with the better-captured SOA magnitude and diurnal variability. The predicted production from anthropogenic and biomass burning S/IVOC represents 40–60% of the total SOA at the surface during the day and is somewhat larger than that from aromatics, especially at the T1 site at the edge of the city. The SOA production from the continued multi-generation S/IVOC oxidation products continues actively downwind. Similar to aircraft observations, the predicted OA/?CO ratio for the ROB case increases from 20–30 ?g sm?3 ppm?1 up to 60–70 ?g sm?3 ppm?1 between a fresh and 1-day aged air mass, while the GRI case produces a 30–40% higher OA growth than observed. The predicted average O/C ratio of total OA for the ROB case is 0.16 at T0, substantially below observed value of 0.5. A much better agreement for O/C ratios and temporal variability (R2=0.63) is achieved with the updated GRI treatment. Both treatments show a deficiency in regard to POA evolution with a tendency to over-evaporate POA upon dilution of the urban plume suggesting that atmospheric HOA may be less volatile than assumed in these parameterizations. This study highlights the important potential role of S/IVOC chemistry in the SOA budget in this region, and highlights the need for improvements in current parameterizations. We note that our simulations did not include other proposed pathways of SOA formation such as formation from very volatile species like glyoxal, which can also contribute SOA mass and especially increase the O/C ratio.

  6. 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. PMID:24526614

  7. Comparisons of diffusive and advective fluxes of gas phase volatile organic compounds (VOCs) in unsaturated zones under natural conditions

    E-print Network

    Zhan, Hongbin

    , and large amounts of organic wastes are ex- pelled carelessly into the subsurface from leaking storage tank, accidental spill of petroleum hydrocarbons, agricultural pesticides usage, etc. Most of these volatile

  8. 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...

  9. A NONSTEADY-STATE ANALYTICAL MODEL TO PREDICT GASEOUS EMISSIONS OF VOLATILE ORGANIC COMPOUNDS FROM LANDFILLS. (R825689C072)

    EPA Science Inventory

    Abstract A general mathematical model is developed to predict emissions of volatile organic compounds (VOCs) from hazardous or sanitary landfills. The model is analytical in nature and includes important mechanisms occurring in unsaturated subsurface landfill environme...

  10. NEAR-REAL-TIME MEASUREMENT OF TRACE VOLATILE ORGANIC COMPOUNDS FROM COMBUSTION PROCESSES USING AN ON-LINE GAS CHROMATOGRAPH

    EPA Science Inventory

    The U.S. EPA's current regulatory approach for combustion and incineration sources emphasizes the use of real-time continuous emission monitors (CEMs) for particulate, Metals, and volatile, semivolatile, and of nonvolatile organic compounds to monitor source emissions. Currently...

  11. A team of researchers is modeling ozone formation induced by volatile organic NORTHWESTERN CHEMICAL AND BIOLOGICAL ENGINEERING

    E-print Network

    Ottino, Julio M.

    mechanistic models based on kinetics and photochemistry, from which predictions of ozone production canA team of researchers is modeling ozone formation induced by volatile organic compounds. NORTHWESTERN CHEMICAL AND BIOLOGICAL ENGINEERING MECHANISTIC MODEL OF OZONE FORMATION Principal Investigator

  12. BIOGENIC VOLATILE ORGANIC COMPOUND EMISSIONS (BVOCS) II. LANDSCAPE FLUX POTENTIALS FROM THREE CONTINENTAL SITES IN THE U.S.

    EPA Science Inventory

    Landscape flux potentials for biogenic volatile organic compounds (BVOCs) were derived for three ecosystems in the continental U. S. (Fernbank Forest, Atlanta, GA; Willow Creek, Rhinelander, WI; Temple Ridge, CO). Analytical data from branch enclosure measurements reported in a ...

  13. PTR-MS analysis of reference and plant-emitted volatile organic compounds

    NASA Astrophysics Data System (ADS)

    Maleknia, Simin D.; Bell, Tina L.; Adams, Mark A.

    2007-05-01

    Proton transfer reaction-mass spectrometry (PTR-MS) was applied to the analysis of a series of volatile organic compounds (VOCs) that emit from various plants. These include a group of alcohols (methanol, ethanol and butanol), carbonyl-containing compounds (acetic acid, acetone and benzaldehyde), isoprene, acetonitrile, tetrahydrofuran (THF), pyrazine, toluene and xylene and a series of terpenes (p-cymene, camphene, 2-carene, limonene, [beta]-myrcene, [alpha]-pinene, [beta]-pinene, [gamma]-tepinene and terpinolene) and oxygen-containing terpenes (1,8-cineole and linalool). These mass spectral data were compared to an electron ionization (EI) database identifying that not all PTR-MS fragments were common to EI. PTR-MS studies of these reference compounds were utilized to identify VOCs emitted from Eucalyptus grandis leaf at a temperature range of 30-100 °C. In addition to protonated molecules (M + H)+, abundant proton-bound dimers or trimers were detected for alcohols, acetone, acetonitrile and THF. Abundant fragment ions attributed to the loss of water from these proton-bound clusters were also observed. The stability of butyl (C4H9+ m/z 57) and acetyl (CH3CO+ m/z 43) fragment ions directed the proton-transfer reactions of butanol and acetic acid. Abundant (M + H)+ ions were detected for pyrazine, THF, toluene and xylene, as well as for all terpenes except those containing oxygen. For linalool and 1,8-cineole, the loss of water generated an abundant fragment ion at m/z 137. PTR-MS fragmentation patterns for terpenes were proposed for m/z 81 (C6H9+), 93 (C7H9+), 95 (C7H11+), 107 (C8H11+), 109 (C8H13+), 119 (C9H11+), 121 (C9H13+) and 137 (loss of water for oxygen-containing terpenes; C10H17+). The relative abundances of (M + H)+ and fragments for all terpenes (except linalool) were dependent on the drift tube voltage and the optimum voltage for detection of molecular ions was different for various terpenes.

  14. Control techniques for volatile organic compound emissions from stationary sources, December 1992. Final report

    SciTech Connect

    Not Available

    1992-12-01

    The document is a summary document containing general information on sources of volatile organic compound (VOC) emissions, applicable control techniques, and the impacts resulting from control applications. It references other documents which contain much more detailed information on individual sources and control techniques. This is the third edition of a report originally published by the Department of Health, Education, and Welfare (HEW) titled, 'Control Techniques for Hydrocarbon and Organic Solvent Emissions from Stationary Sources (AP-68).' The first edition was published in March 1970 by the National Air Pollution Control Administration, a part of HEW.

  15. Effect of volatile fatty acids on seedling growth of anoxia-tolerant rice (Oryza sativa L.) genotypes

    Microsoft Academic Search

    Jiban Krishna Biswas; Ho Ando; Ken-ichi Kakuda

    2001-01-01

    Some of the rice genotypes were selected as anoxia-tolerant. But when seeded directly in lowland soil, the seedling establishment of these genotypes varied with the locations. It was assumed that volatile fatty acids (VFA) like acetic, propionic, or butyric acid might be one of the factors that affected this phenomenon along with the pH level. Very specific data related to

  16. Reduction of volatile fatty acids and odor offensiveness by anaerobic digestion and solid separation of dairy manure during manure storage.

    PubMed

    Page, Laura H; Ni, Ji-Qin; Zhang, Hao; Heber, Albert J; Mosier, Nathan S; Liu, Xingya; Joo, Hung-Soo; Ndegwa, Pius M; Harrison, Joseph H

    2015-04-01

    Volatile fatty acids (VFA) play an important role in the biodegradation of organic wastes and production of bioenergy under anaerobic digestion, and are related to malodors. However, little is known about the dynamics of VFA during dairy manure storage. This study evaluated the characteristics of VFA in dairy manure before and after anaerobic co-digestion in a laboratory experiment using eight lab-scale reactors. The reactors were loaded with four different types of dairy manure: (1) liquid dairy manure from a freestall barn, (2) mixture of dairy manure and co-digestion food processing wastes at the inlet of an anaerobic digester, (3) effluent from the digester outlet, and (4) the liquid fraction of effluent from a solid separator. Four VFA (acetic, propionic, butyric, and 2-methylbutyric acids) were identified and quantified in weekly manure samples from all reactors. Results showed that the dominant VFA was acetic acid in all four manure sources. The off-farm co-digestion wastes significantly increased the total VFA concentrations and the proportions of individual VFA in the influent. The dairy manure under storage demonstrated high temporal and spatial variations in pH and VFA concentrations. Anaerobic digestion reduced the total VFA by 86%-96%; but solid-liquid separation did not demonstrate a significant reduction in total VFA in this study. Using VFA as an indicator, anaerobic digestion exhibited an effective reduction of dairy manure odor offensiveness. PMID:25617873

  17. Determination of volatility distributions of primary organic aerosol emissions from internal combustion engines using thermal desorption gas chromatography mass spectrometry

    Microsoft Academic Search

    Albert A. Presto; Christopher J. Hennigan; Ngoc T. Nguyen; Allen L. Robinson

    2012-01-01

    A new technique for measuring the primary organic aerosol emissions from internal combustion engines is presented. The method combines thermal-optical OC\\/EC analysis and thermal desorption gas chromatography mass spectrometry (TD-GC-MS) of quartz filter samples collected using a dilution sampler to quantify the total emissions of low-volatility organics and to distribute them across the volatility basis set. These data can be

  18. Improved sparger for purge and trap concentrator used for the analysis of volatile organics in landfill leachates and septic samples

    SciTech Connect

    Chichester-Constable, D.J.; Barbeau, M.E.; Liu, S.L.; Smith, S.R.; Stuart, J.D.

    1987-01-01

    An improved sparger unit, part of a commercially available purge and trap concentrator, has allowed for the determination of volatile organics in very dirty landfill leachates and septic samples. The loss of volatile organics is minimized during transfer steps by using the same glass tube for sample collection, for storage and for the analytical sparging operation. Chemometrics was used to compare the sparging efficiency of the original and the improved sparger unit.

  19. Enhancers of iron absorption: ascorbic acid and other organic acids.

    PubMed

    Teucher, Birgit; Olivares, Manuel; Cori, Héctor

    2004-11-01

    Ascorbic acid (AA), with its reducing and chelating properties, is the most efficient enhancer of non-heme iron absorption when its stability in the food vehicle is ensured. The number of studies investigating the effect of AA on ferrous sulfate absorption far outweighs that of other iron fortificants. The promotion of iron absorption in the presence of AA is more pronounced in meals containing inhibitors of iron absorption. Meals containing low to medium levels of inhibitors require the addition of AA at a molar ratio of 2:1 (e.g., 20 mg AA: 3 mg iron). To promote absorption in the presence of high levels of inhibitors, AA needs to be added at a molar ratio in excess of 4:1, which may be impractical. The effectiveness of AA in promoting absorption from less soluble compounds, such as ferrous fumarate and elemental iron, requires further investigation. The instability of AA during food processing, storage, and cooking, and the possibility of unwanted sensory changes limits the number of suitable food vehicles for AA, whether used as vitamin fortificant or as an iron enhancer. Suitable vehicles include dry-blended foods, such as complementary, precooked cereal-based infant foods, powdered milk, and other dry beverage products made for reconstitution that are packaged, stored, and prepared in a way that maximizes retention of this vitamin. The consumption of natural sources of Vitamin C (fruits and vegetables) with iron-fortified dry blended foods is also recommended. Encapsulation can mitigate some of the AA losses during processing and storage, but these interventions will also add cost. In addition, the bioavailability of encapsulated iron in the presence/absence of AA will need careful assessment in human clinical trials. The long-term effect of high AA intake on iron status may be less than predicted from single meal studies. The hypothesis that an overall increase of dietary AA intake, or fortification of some foods commonly consumed with the main meal with AA alone, may be as effective as the fortification of the same food vehicle with AA and iron, merits further investigation. This must involve the consideration of practicalities of implementation. To date, programs based on iron and AA fortification of infant formulas and cow's milk provide the strongest evidence for the efficacy of AA fortification. Present results suggest that the effect of organic acids, as measured by in vitro and in vivo methods, is dependent on the source of iron, the type and concentration of organic acid, pH, processing methods, and the food matrix. The iron absorption-enhancing effect of AA is more potent than that of other organic acids due to its ability to reduce ferric to ferrous iron. Based on the limited data available, other organic acids may only be effective at ratios of acid to iron in excess of 100 molar. This would translate into the minimum presence/addition of 1 g citric acid to a meal containing 3 mg iron. Further characterization of the effectiveness of various organic acids in promoting iron absorption is required, in particular with respect to the optimal molar ratio of organic acid to iron, and associated feasibility for food application purposes. The suggested amount of any organic acid required to produce a nutritional benefit will result in unwanted organoleptic changes in most foods, thus limiting its application to a small number of food vehicles (e.g., condiments, beverages). However, fermented foods that already contain high levels of organic acid may be suitable iron fortification vehicles. PMID:15743017

  20. Water-enhanced solubility of carboxylic acids in organic solvents and its application to extraction processes

    SciTech Connect

    Starr, J.N. (Abbott Labs., North Chicago, IL (United States)); King, C.J. (Lawrence Berkeley Lab., CA (United States))

    1992-11-01

    This paper reports on solubilities of carboxylic acids in certain organic solvents which increase sharply as the concentration of water in the solvent increases. This phenomenon leads to a method of regeneration for solvent-extraction processes whereby coextracted water is selectively removed from the extract, such as by stripping, thereby precipitating the acid. The removal of a minor constituent to cause precipitation reduces energy consumption, in contrast with bulk removal of solvent. Solubilities of fumaric acid were measured in a number of organic solvents, with varying amounts of water in the organic phase. Cyclohexanone and methylcyclohexanone were chosen as solvents for which detailed solid-liquid and liquid-liquid equilibria were measured for adipic, fumaric, and succinic acids in the presence of varying concentrations of water, at both 25 and 45[degrees]C. Batch precipitation experiments were performed to demonstrate the processing concept and determine the relative volatility of water to solvent in the presence of carbon.

  1. Tropospheric Chemistry of Internally Mixed Sea Salt and Organic Particles: Surprising Reactivity of NaCl with Weak Organic Acids

    SciTech Connect

    Laskin, Alexander; Moffet, Ryan C.; Gilles, Marry K.; Fast, Jerome D.; Zaveri, Rahul A.; Wang, Bingbing; Nigge, P.; Shutthanandan, Janani I.

    2012-08-03

    Chemical imaging analysis of internally mixed sea salt/organic particles collected on board the Department of Energy (DOE) G-1 aircraft during the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES) was performed using electron microscopy and X-ray spectro-microscopy techniques. Substantial chloride depletion in aged sea salt particles was observed, which could not be explained by the known atmospheric reactivity of sea salt with inorganic nitric and sulfuric acids. We present field evidence that chloride components in sea salt particles may effectively react with organic acids releasing HCl gas to the atmosphere, leaving behind particles depleted in chloride and enriched in the corresponding organic salts. While formation of the organic salts products is not thermodynamically favored for bulk aqueous chemistry, these reactions in aerosol are driven by high volatility and irreversible evaporation of the HCl product from drying particles. These field observations were corroborated in a set of laboratory experiments where NaCl particles mixed with organic acids were found to be depleted in chloride. Combined together, the results indicate substantial chemical reactivity of sea salt particles with secondary organics that has been largely overlooked in the atmospheric aerosol chemistry. Atmospheric aging, and especially hydration-dehydration cycles of mixed sea salt/organic particles may result in formation of organic salts that will modify acidity, hygroscopic and optical properties of aged particles.

  2. Tropospheric chemistry of internally mixed sea salt and organic particles: Surprising reactivity of NaCl with weak organic acids

    NASA Astrophysics Data System (ADS)

    Laskin, Alexander; Moffet, Ryan C.; Gilles, Mary K.; Fast, Jerome D.; Zaveri, Rahul A.; Wang, Bingbing; Nigge, Pascal; Shutthanandan, Janani

    2012-08-01

    Chemical imaging analysis of internally mixed sea salt/organic particles collected onboard the Department of Energy (DOE) G-1 aircraft during the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES) was performed using electron microscopy and X-ray spectro-microscopy. Substantial chloride depletion in aged sea salt particles was observed, which could not be explained by the known atmospheric reactivity of sea salt with inorganic nitric and sulfuric acids. We present field evidence that chloride components in sea salt particles may effectively react with organic acids releasing HCl gas to the atmosphere, leaving behind particles depleted in chloride and enriched in the corresponding organic salts. While formation of the organic salts products is not thermodynamically favored for bulk aqueous chemistry, these reactions in aerosol are driven by high volatility and evaporation of the HCl product from drying particles. These field observations were corroborated in a set of laboratory experiments where NaCl particles mixed with organic acids were found to be depleted in chloride. Combined together, the results indicate substantial chemical reactivity of sea salt particles with secondary organics that has been largely overlooked in the atmospheric aerosol chemistry. Atmospheric aging, and in particular hydration-dehydration cycles of mixed sea salt/organic particles, may result in formation of organic salts that will modify the acidity, hygroscopic, and optical properties of aged particles.

  3. Removal of volatile organic compounds using amphiphilic cyclodextrin-coated polypropylene

    PubMed Central

    Lumholdt, Ludmilla; Fourmentin, Sophie; Nielsen, Thorbjørn T

    2014-01-01

    Summary 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. PMID:25550739

  4. Reconciling Organic Aerosol Volatility, Hygroscopicity, and Oxidation State During the Colorado DISCOVER-AQ Deployment

    NASA Astrophysics Data System (ADS)

    Hite, J. R.; Moore, R.; Martin, R.; Thornhill, K. L., II; Winstead, E.; Anderson, B. E.; Nenes, A.

    2014-12-01

    The organic fraction of submicron aerosol can profoundly impact radiative forcing on climate directly, through enhancement of extinction, or indirectly through modulation of cloud formation. Semi-volatile constituents of organic ambient aerosol are of particular interest as their partitioning between the vapor and aerosol phases is not well constrained by current atmospheric models and appears to play an important role in the formation of cloud condensation nuclei (CCN) as suggested by recent research. An experimental setup consisting of a DMT CCN counter and SMPS downstream of a custom-built thermodenuder assembly was deployed during the summer 2014 DISCOVER-AQ field campaign to retrieve simultaneous, size-resolved volatility and hygroscopicity - through the use of scanning mobility CCN analysis (SMCA). Housed in the NASA Langley mobile laboratory, a suite of complimentary measurements were made available onboard including submicron aerosol composition and oxidation state provided by an HR-ToF-AMS, and aerosol optical properties provided by a range of other instruments including an SP2. Air masses sampled from locations across the Central Colorado region include influences from regional aerosol nucleation/growth events, long-range transport of Canadian biomass burning aerosols, cattle feedlot emissions and influences of the Denver urban plume - amidst a backdrop of widespread oil and gas exploration. The analysis focuses on the reconciliation of the retrieved aerosol volatility distributions and corresponding hygroscopicity and oxidation state observations, including the use of AMS factor analysis.

  5. Soft ionization chemical analysis of secondary organic aerosol from green leaf volatiles emitted by turf grass.

    PubMed

    Jain, Shashank; Zahardis, James; Petrucci, Giuseppe A

    2014-05-01

    Globally, biogenic volatile organic compound (BVOC) emissions contribute 90% of the overall VOC emissions. Green leaf volatiles (GLVs) are an important component of plant-derived BVOCs, including cis-3-hexenylacetate (CHA) and cis-3-hexen-1-ol (HXL), which are emitted by cut grass. In this study we describe secondary organic aerosol (SOA) formation from the ozonolysis of dominant GLVs, their mixtures and grass clippings. Near-infrared laser desorption/ionization aerosol mass spectrometry (NIR-LDI-AMS) was used for chemical analysis of the aerosol. The chemical profile of SOA generated from grass clippings was correlated with that from chemical standards of CHA and HXL. We found that SOA derived from HXL most closely approximated SOA from turf grass, in spite of the approximately 5× lower emission rate of HXL as compared to CHA. Ozonolysis of HXL results in formation of low volatility, higher molecular weight compounds, such as oligomers, and formation of ester-type linkages. This is in contrast to CHA, where the hydroperoxide channel is the dominant oxidation pathway, as oligomer formation is inhibited by the acetate functionality. PMID:24666343

  6. Effects of chemical aging on global secondary organic aerosol using the volatility basis set approach

    NASA Astrophysics Data System (ADS)

    Jo, D. S.; Park, R. J.; Kim, M. J.; Spracklen, D. V.

    2013-12-01

    A global 3-D chemical transport model (GEOS-Chem) is used with the volatility basis set (VBS) approach to examine the effects of chemical aging on global secondary organic aerosol (SOA) concentrations and budgets. We present full-year simulations and their comparisons with the global aerosol mass spectrometer (AMS) dataset, the Interagency Monitoring of Protected Visual Environments (IMPROVE) dataset from the United States, the European Monitoring and Evaluation Programme (EMEP) dataset from Europe, and water-soluble organic carbon observation data collected over East Asia. Using different chemical aging constants, we find that the model results with 4 × 10-11 cm3 molecule-1 s-1 are in better agreement with all observations relative to the model results with other aging constants, without aging, and with the two-product approach. The model simulations are improved when chemical aging is considered, especially for rural regions. However, the simulations still underestimate observed oxygenated organic aerosol (OOA) in urban areas. Two sensitivity simulations including semi-volatile primary organic aerosol (POA) were conducted. We find that including semi-volatile POA improves the model in terms of the hydrogen-like organic aerosol (HOA) to OOA ratio. However, the total OA concentrations are not improved. The total SOA production is considerably increased by 53%, from 26.0 to 39.9 Tg yr-1, after considering chemical aging, remaining lower than top-down estimates of SOA production. Direct radiative forcing (DRF) increases by -0.07 W m-2 due to the chemical aging of SOA, which is comparable to the mean DRF (-0.13 W m-2) of OA from the AeroCom multi-model study. This result indicates considerable global and, more importantly, regional climate implications. For example, the regional DRF change due to chemical aging of SOA in the eastern US is -0.29 W m-2, which is 4 times greater in magnitude than the global mean value.

  7. Interlaboratory evaluation of volatile organic compound determinations in soils prepared by vapor fortification

    SciTech Connect

    Hewitt, A.D. [Army Cold Regions Research and Engineering Lab., Hanover, NH (United States); Grant, C.L. [Univ. of New Hampshire, Durham, NH (United States)

    1995-12-31

    The feasibility of using vapor fortification to prepare secondary soil standards containing volatile organic compounds (VOCs) was evaluated by an interlaboratory study. Twelve laboratories used EPA Method 8240 (SW846) to analyze two independently prepared subsamples of three different soil matrices fortified with trans-1,2-dichloroethylene (TDCE), trichloroethylene (TCE), benzene (Ben), and toluene (Tol). A quality assurance (QA) standard with certified concentrations of TCE, Ben, and Tol (no TDCE) was also analyzed. The pooled relative standard deviation (RSD) for the QA standard was 7.8%, while the same analytes in the soils produced a pooled RSD of 10.4%. Agreement of these precision estimates is excellent, considering that soil analysis required an extraction step while the QA Standard was solvent (methanol) based. TDCE in the soils yielded less precise results (pooled RSD of 20.3%), presumably because of its high volatility.

  8. Energy densification of biomass-derived organic acids

    DOEpatents

    Wheeler, M. Clayton; van Walsum, G. Peter; Schwartz, Thomas J.; van Heiningen, Adriaan

    2013-01-29

    A process for upgrading an organic acid includes neutralizing the organic acid to form a salt and thermally decomposing the resulting salt to form an energy densified product. In certain embodiments, the organic acid is levulinic acid. The process may further include upgrading the energy densified product by conversion to alcohol and subsequent dehydration.

  9. Fungal colonization of air filters and insulation in a multi-story office building: production of volatile organics

    NASA Technical Reports Server (NTRS)

    Ahearn, D. G.; Crow, S. A.; Simmons, R. B.; Price, D. L.; Mishra, S. K.; Pierson, D. L.

    1997-01-01

    Secondary air filters in the air-handling units on four floors of a multi-story office building with a history of fungal colonization of insulation within the air distribution system were examined for the presence of growing fungi and production of volatile organic compounds. Fungal mycelium and conidia of Cladosporium and Penicillium spp. were observed on insulation from all floors and both sides of the air filters from one floor. Lower concentrations of volatile organics were released from air filter medium colonized with fungi as compared with noncolonized filter medium. However, the volatiles from the colonized filter medium included fungal metabolites such as acetone and a carbonyl sulfide-like compound that were not released from noncolonized filter medium. The growth of fungi in air distribution systems may affect the content of volatile organics in indoor air.

  10. Fungal colonization of air filters and insulation in a multi-story office building: production of volatile organics.

    PubMed

    Ahearn, D G; Crow, S A; Simmons, R B; Price, D L; Mishra, S K; Pierson, D L

    1997-11-01

    Secondary air filters in the air-handling units on four floors of a multi-story office building with a history of fungal colonization of insulation within the air distribution system were examined for the presence of growing fungi and production of volatile organic compounds. Fungal mycelium and conidia of Cladosporium and Penicillium spp. were observed on insulation from all floors and both sides of the air filters from one floor. Lower concentrations of volatile organics were released from air filter medium colonized with fungi as compared with noncolonized filter medium. However, the volatiles from the colonized filter medium included fungal metabolites such as acetone and a carbonyl sulfide-like compound that were not released from noncolonized filter medium. The growth of fungi in air distribution systems may affect the content of volatile organics in indoor air. PMID:9462961

  11. Authentication of dried distilled grain with solubles (DDGS) by fatty acid and volatile profiling.

    PubMed

    Tres, Alba; Heenan, Samuel P; van Ruth, Saskia

    2014-11-01

    Demand for ethanol substituted fuels from the utilisation of cereal based biofuel has resulted in an over production of dried distillers grains with solubles (DDGS) that are now readily available on the animal feed market. With this rapid emerging availability comes potential variability in the nutritional value of DDGS and possible risks of feed contaminants. Subsequently, the authentication and traceability of alternative animal feed sources is of high priority. In this study and as part of the EU research project "Quality and Safety of Feeds and Food for Europe (QSAFFE FP7-KBBE-2010-4) an attempt was made to classify the geographical origin of cereal grains used in the production of DDGS material. DDGS material of wheat and corn origin were obtained from Europe, China, and the USA. Fatty acid profiles and volatile fingerprints were assessed by gas chromatography flame ionisation (GC-FID) and rapid proton transfer reaction mass spectrometry (PTR-MS) respectively. Chemometric analysis of fatty acid profiles and volatile fingerprints allowed for promising classifications of cereals used in DDGS material by geographical and botanical origin and enabled visual representation of the data. This objective analytical approach could be adapted for routine verification of cereal grains used in the production of DDGS material. PMID:25368433

  12. Authentication of dried distilled grain with solubles (DDGS) by fatty acid and volatile profiling

    PubMed Central

    Tres, Alba; Heenan, Samuel P.; van Ruth, Saskia

    2014-01-01

    Demand for ethanol substituted fuels from the utilisation of cereal based biofuel has resulted in an over production of dried distillers grains with solubles (DDGS) that are now readily available on the animal feed market. With this rapid emerging availability comes potential variability in the nutritional value of DDGS and possible risks of feed contaminants. Subsequently, the authentication and traceability of alternative animal feed sources is of high priority. In this study and as part of the EU research project “Quality and Safety of Feeds and Food for Europe (QSAFFE FP7-KBBE-2010-4) an attempt was made to classify the geographical origin of cereal grains used in the production of DDGS material. DDGS material of wheat and corn origin were obtained from Europe, China, and the USA. Fatty acid profiles and volatile fingerprints were assessed by gas chromatography flame ionisation (GC-FID) and rapid proton transfer reaction mass spectrometry (PTR-MS) respectively. Chemometric analysis of fatty acid profiles and volatile fingerprints allowed for promising classifications of cereals used in DDGS material by geographical and botanical origin and enabled visual representation of the data. This objective analytical approach could be adapted for routine verification of cereal grains used in the production of DDGS material. PMID:25368433

  13. Volatile organic components of air samples collected from Vertical Launch Missile capsules. Summary report

    SciTech Connect

    Tappan, D.V.; Knight, D.R.; Heyder, E.; Weathersby, P.K.

    1988-09-27

    Gas chromatographic/mass spectroscopic analyses are presented for the volatile organic components found in air samples collected from the inboard vents from Vertical Launch System (VLS) missile capsules aboard a 688 class submarine. Similar analyses were also conducted for a sample of the ship's high pressure air used to fill the missile tubes. A wide variety of organics was detected in the air from the missile capsules; and while no unique components have yet been identified, a significant contribution has been shown to be made by pressure-ventilation of the VLS capsules into the submarine atmosphere which is already heavily laden with volatile organic compounds. The most apparent conclusion from these preliminary analyses is that the mixtures of organic components in the air within VLS missile capsules vary greatly from capsule to capsule (and probably from time to time). Many such samples need to be investigated to provide sufficient information to judge the seriousness of the possibility of venting toxic components into the submarine atmosphere during the maintenance or firing of VLS missiles.

  14. [Quantification assessment of the relationship between chemical and olfactory concentrations for malodorous volatile organic compounds].

    PubMed

    Liu, Shu-Le; Wang, Bo-Guang; He, Jie; Tang, Xiao-Dong; Zhao, De-Jun; Guo, Wei

    2011-12-01

    Using self-made cold-traps and gas bags, the odor samples were collected from 6 sewage treatment workshops of a typical municipal sewage treatment plant in Guangzhou City. The chemical composition and olfactory concentrations of these samples were respectively analyzed by thermal-desorption/GC-MS and triangle odor bag method. Finally, a mathematical equation was built for assessing the relationship between principal organic odorants and the olfactory concentrations. The result showing that: (1) More than 70 volatile organic compounds were detected in municipal sewage treatment plant, among which were 30 malodorous volatile organic compounds (MVOCs), ranging from 0.37 to 1 872.24 microg x m(-3) and appearing in sludge dewatering, thickening and aeration tank with the highest concentrations. (2) Principle component analysis was used to group the target MVOCs into 5 categories: benzenes, halohydrocarbons, aldehydes, hydrocarbons and S, N-containing organic compounds. (3) Multiple lineal regression analysis was used to build a quantified relationship between chemical and olfactory concentrations of MVOCs. The result indicated that 25% of the odor problem of sewage treatment unit was due to MVOCs. The predicted values were fitting well with measured values. The sensitivity of mathematical equation for measuring odor concentration was higher than that of human olfactory system. PMID:22468522

  15. The impact of acetate metabolism on yeast fermentative performance and wine quality: reduction of volatile acidity of grape musts and wines

    Microsoft Academic Search

    Alice Vilela-Moura; Dorit Schuller; Arlete Mendes-Faia; Rui D. Silva; Susana R. Chaves; Maria João Sousa; Manuela Côrte-Real

    2011-01-01

    Acetic acid is the main component of the volatile acidity of grape musts and wines. It can be formed as a by-product of alcoholic\\u000a fermentation or as a product of the metabolism of acetic and lactic acid bacteria, which can metabolize residual sugars to\\u000a increase volatile acidity. Acetic acid has a negative impact on yeast fermentative performance and affects the

  16. Volatile organic compounds and metal leaching from composite products made from fiberglass-resin portion of printed circuit board waste.

    PubMed

    Guo, Jie; Jiang, Ying; Hu, Xiaofang; Xu, Zhenming

    2012-01-17

    This study focused on the volatile organic compounds (VOCs) and metal leaching from three kinds of composite products made from fiberglass-resin portion (FRP) of crushed printed circuit board (PCB) waste, including phenolic molding compound (PMC), wood plastic composite (WPC), and nonmetallic plate (NMP). Released VOCs from the composite products were quantified by air sampling on adsorbent followed by thermal desorption and GC-MS analysis. The results showed that VOCs emitted from composite products originated from the added organic components during manufacturing process. Phenol in PMC panels came primarily from phenolic resin, and the airborne concentration of phenol emitted from PMC product was 59.4 ± 6.1 ?g/m(3), which was lower than odor threshold of 100% response for phenol (180 ?g/m(3)). VOCs from WPC product mainly originated from wood flour, e.g., benzaldehyde, octanal, and d-limonene were emitted in relatively low concentrations. For VOCs emitted from NMP product, the airborne concentration of styrene was the highest (633 ± 67 ?g/m(3)). Leaching characteristics of metal ions from composite products were tested using acetic acid buffer solution and sulphuric acid and nitric acid solution. Then the metal concentrations in the leachates were tested by ICP-AES. The results showed that only the concentration of Cu (average = 893 mg/L; limit = 100 mg/L) in the leachate solution of the FRP using acetic acid buffer solution exceeded the standard limit. However, concentrations of other metal ions (Pb, Cd, Cr, Ba, and Ni) were within the standard limit. All the results indicated that the FRP in composite products was not a major concern in terms of environmental assessment based upon VOCs tests and leaching characteristics. PMID:22142243

  17. Urinary metabolites of a polycyclic aromatic hydrocarbon and volatile organic compounds in relation to lung cancer development in lifelong never smokers in the Shanghai Cohort Study

    PubMed Central

    Yuan, Jian-Min

    2014-01-01

    Exposures to polycyclic aromatic hydrocarbons (PAHs) from various environmental and occupational sources are considered a primary risk factor for lung cancer among lifelong never smokers, based largely on results from epidemiologic studies utilizing self-reported exposure information. Prospective, biomarker-based human studies on the role of PAH and other airborne carcinogens in the development of lung cancer among lifelong non-smokers have been lacking. We prospectively investigated levels of urinary metabolites of a PAH and volatile organic compounds in relation to lung cancer risk in a nested case–control study of 82 cases and 83 controls among lifelong never smokers of the Shanghai Cohort Study, a prospective cohort of 18 244 Chinese men aged 45–64 years at enrollment. We quantified three PAH metabolites: r-1,t-2,3,c-4-tetrahydroxy-1,2,3,4-tetrahydrophenanthrene (PheT), 3-hydroxyphenanthrene (3-OH-Phe) and total hydroxyphenanthrenes (total OH-Phe, the sum of 1-, 2-, 3- and 4-OH-Phe), as well as metabolites of the volatile organic compounds acrolein (3-hydroxypropyl mercapturic acid), benzene (S-phenyl mercapturic acid), crotonaldehyde (3-hydroxy-1-methylpropylmercapturic acid) and ethylene oxide (2-hydroxyethyl mercapturic acid). Urinary cotinine was also quantified to confirm non-smoking status. Compared with the lowest quartile, odds ratios (95% confidence intervals) for lung cancer risk for the highest quartile levels of PheT, 3-OH-Phe and total OH-Phe were 2.98 (1.13–7.87), 3.10 (1.12–7.75) and 2.59 (1.01–6.65) (all P trend < 0.05), respectively. None of the metabolites of the volatile organic compounds were associated with overall lung cancer risk. This study demonstrates a potentially important role of exposure to PAH in the development of lung cancer among lifelong never smokers. PMID:24148823

  18. Urinary metabolites of a polycyclic aromatic hydrocarbon and volatile organic compounds in relation to lung cancer development in lifelong never smokers in the Shanghai Cohort Study.

    PubMed

    Yuan, Jian-Min; Butler, Lesley M; Gao, Yu-Tang; Murphy, Sharon E; Carmella, Steven G; Wang, Renwei; Nelson, Heather H; Hecht, Stephen S

    2014-02-01

    Exposures to polycyclic aromatic hydrocarbons (PAHs) from various environmental and occupational sources are considered a primary risk factor for lung cancer among lifelong never smokers, based largely on results from epidemiologic studies utilizing self-reported exposure information. Prospective, biomarker-based human studies on the role of PAH and other airborne carcinogens in the development of lung cancer among lifelong non-smokers have been lacking. We prospectively investigated levels of urinary metabolites of a PAH and volatile organic compounds in relation to lung cancer risk in a nested case-control study of 82 cases and 83 controls among lifelong never smokers of the Shanghai Cohort Study, a prospective cohort of 18 244 Chinese men aged 45-64 years at enrollment. We quantified three PAH metabolites: r-1,t-2,3,c-4-tetrahydroxy-1,2,3,4-tetrahydrophenanthrene (PheT), 3-hydroxyphenanthrene (3-OH-Phe) and total hydroxyphenanthrenes (total OH-Phe, the sum of 1-, 2-, 3- and 4-OH-Phe), as well as metabolites of the volatile organic compounds acrolein (3-hydroxypropyl mercapturic acid), benzene (S-phenyl mercapturic acid), crotonaldehyde (3-hydroxy-1-methylpropylmercapturic acid) and ethylene oxide (2-hydroxyethyl mercapturic acid). Urinary cotinine was also quantified to confirm non-smoking status. Compared with the lowest quartile, odds ratios (95% confidence intervals) for lung cancer risk for the highest quartile levels of PheT, 3-OH-Phe and total OH-Phe were 2.98 (1.13-7.87), 3.10 (1.12-7.75) and 2.59 (1.01-6.65) (all P trend < 0.05), respectively. None of the metabolites of the volatile organic compounds were associated with overall lung cancer risk. This study demonstrates a potentially important role of exposure to PAH in the development of lung cancer among lifelong never smokers. PMID:24148823

  19. Molecular characterization of polar organosulfates in secondary organic aerosol from the green leaf volatile 3-Z-hexenal

    NASA Astrophysics Data System (ADS)

    Safi Shalamzari, Mohammad; Kahnt, Ariane; Wang, Wu; Vermeylen, Reinhilde; Kleindienst, Tadeusz; Lewandovski, Michael; Maenhaut, Willy; Claeys, Magda

    2014-05-01

    Much information is available about secondary organic aerosol (SOA) formation from terpenes, including mono- and sesquiterpenes, and isoprene. However, information about SOA formation from green leaf volatiles (GLVs), an important class of biogenic volatile organic compounds, which are emitted when plants are wounded or attacked by insects, is very scarce. In the present study, we provide evidence that 3-Z-hexenal is a potential precursor for SOA through formation of organosulfates. Organosulfate formation from 3-Z-hexenal was studied by conducting smog chamber photooxidation experiments in the presence of NO and acidic ammonium seed aerosol, where OH radicals were generated from the NOx mediated photochemical chain reactions. The focus of the study was on the structural characterization of products, i.e., organosulfates (OSs) with a molecular weight (MW) of 226, which are also present in ambient fine aerosol from a forested site (K puszta, Hungary) at a substantial relative abundance that is comparable to that of the MW 216 isoprene-related OSs. Polar OSs are of climatic relevance because of their capacity to increase the hydrophilic properties of aerosols and as such their cloud-condensation nuclei effects. Two different liquid chromatography (LC) techniques were employed to separate the polar OSs: the first technique uses a reversed-phase trifunctionally bonded C18 stationary phase, whereas the second one is based on ion-pairing C18 LC using dibutylammonium acetate as ion-pairing reagent. With regard to mass spectrometry (MS) techniques, use was made of high-resolution MS to determine the accurate mass (measured mass, 225.00809; elemental composition, C6H9O7S) as well as linear ion trap MS to obtain detailed structural information. The MW 226 OSs were structurally characterized as sulfated derivatives of 3,4-dihydroxyhex-2-enoic acid with the sulfate group positioned at C-3 or C-4. The formation of these OSs is explained through photooxidation in the gas phase resulting in a hydroperoxide, followed by acid-catalyzed rearrangement into an epoxyhydroxide and subsequent sulfation of the epoxy group in the particle phase. This work was supported by the Belgian Federal Science Policy Office through the network project "Biogenic Influence on Oxidants and Secondary Organic Aerosol: theoretical, laboratory and modeling investigations (BIOSOA)" and the Research Foundation - Flanders (FWO).

  20. Emissions of volatile organic compounds from vegetation and the implications for atmospheric chemistry

    Microsoft Academic Search

    Fred Fehsenfeld; Jack Calvert; Ray Fall; Paul Goldan; A. B. Guenther; C. N. Hewitt; Brian Lamb; Shaw Liu; Michael Trainer; Hal Westberg; Pat Zimmerman

    1992-01-01

    Vegetation provides a major source of reactive carbon entering the atmosphere. These compounds play an important role in (1) shaping global tropospheric chemistry, (2) regional photochemical oxidant formation, (3) balancing the global carbon cycle, and (4) production of organic acids which contribute to acidic deposition in rural areas. Present estimates place the total annual global emission of these compounds between