scholarly journals Nature of Volatile Organic Matter in Lake Sediments as a Reflection of Paleoclimate Changes Occurring at 4 ka in the Central Qaidam Basin

2021 ◽  
Vol 9 ◽  
Author(s):  
Xiaohang Lu ◽  
Yongsheng Zhang ◽  
Lei Yi ◽  
Zhe Ma ◽  
Weigang Su ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Compound ◽  
Lake Sediments ◽  
Organic Compounds ◽  
Negative Correlation ◽  
Qaidam Basin ◽  
Silty Sand ◽  
Strong Positive Correlation ◽  
Significant Difference ◽  
Volatile Organic

This study explores the paleoclimate changes around the 4 ka BP period in the central Qaidam Basin (QB), assessing the differences in spectral characteristics and organic composition of salt lake sediments under different climate change conditions. Sediment samples (10-m-depth profile) were collected from the middle of dry salt flats in East Taijinar Lake (China). Sediment organic matter (SOM) was assessed by Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GC-MS). Results showed a significant difference in the TOC content of sediments with different lithological characteristics. A lower TOC content in salt-bearing strata was attributed to the extreme sedimentary environment with minimal exogenous inputs. FTIR spectroscopy revealed that the SOM in sediments included aliphatic C, ketones and alcohols. Sediments of salt-bearing strata generally exhibited a rise in the content of ketone C=O groups and a decrease in aliphatic C, with an equal content of alcohols compared with silty sand. Therefore, exogenous OM and the content of TOC in silty sand strata are higher than in salt-bearing strata, indicating that the paleoclimate became warmer and wetter after 4 ka BP. GC-MS analysis showed a significant difference between the phenol and aldehyde content in different strata, further indicating that the paleoclimate changed from dry to relatively warm around 4 ka BP. Seven organic compound types were identified in SOM, including aldehydes, hydrocarbons, phenols, esters, ketones, alcohols, and furans. Different strata exhibited different distributions of organic compounds, with particularly high concentrations of aldehydes in salt-bearing strata and phenols in silty sand. Correlation analysis was performed between detrital minerals and OM types in all samples. Results showed a strong positive correlation between detrital minerals and phenols and a strong negative correlation between detrital minerals and aldehydes, with a negative correlation also identified between detrital minerals and ketones. Overall, the reduction in volatile organic compounds demonstrates that the paleoclimate changed from cooler and dry to wet and warm around the 4 ka BP period in the central QB, with the carbon preference index and n-alkane values further demonstrating these results. This study also confirms the importance of volatile organic compound monitoring to assess paleoclimate changes.

scholarly journals The Composition and Distribution of Volatile Organic Compounds in Sediments of the East Taijinar Salt Lake in Northern Qinghai-Tibet Plateau

2021 ◽  
Vol 2 ◽  
Author(s):  
Xiaohang Lu ◽  
Zhe Ma ◽  
Lei Yi ◽  
Guangwu Zhang ◽  
Fuhong Chen ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Organic Matter ◽  
Volatile Organic Compounds ◽  
Lake Sediments ◽  
Organic Compounds ◽  
Salt Lake ◽  
Sediment Samples ◽  
Group I ◽  
Volatile Organic ◽  
Biological Sources

The main objective of this study was to explore the composition and distribution of volatile organic compounds (VOCs) and the factors that affect their distribution in the salt lake sediments. Thirteen sediment samples were collected from a depth profile in the East Taijinar Lake, China. VOCs of different samples were extracted by headspace solid phase microextraction. Gas chromatography-ion mobility spectrometry, gas chromatography-mass spectrometry, and X-ray diffraction were used to analyze the VOCs, n-alkanes, and minerals present in samples. Thirty-four VOCs were identified and classified into seven types, including terpenes, furans, esters, aldehydes, ketones, alcohols, and acids, apart from six contaminants. It was found that 24 of the most prevalent compounds in clay were on average 101.45% higher than those in sandstone and halite because of the sedimentary environment, while the remaining ten (2-acetylfuran, 2-pinene D, etc.) were on average 13.27% higher in sandstone and halite sediments than in clay. This can be attributed to their different biological sources, porosity, and higher salinity. Based on the Q-cluster analysis, the 13 sediment samples were split into two groups, including the group according to composition and the group based on distribution of VOCs. In this study, it was found that the VOCs correlate positively with detrital minerals, with Group I exhibiting a high content of detrital minerals (>25%), while Group II showed the opposite characteristics. The consumption of organic matter (OM) by microorganisms leads to the formation of VOCs in sediment. The values of carbon preference index and n-alkane further demonstrate that the organic matter of the two groups came from different sources, exogenous and endogenous. Pr/Ph ratios, Pr/C17, and Pr/C18 also suggest that the OM in all sediments was strongly affected by microorganisms in an anoxic environment. Together, these results demonstrate that the OM from different biological sources and microbial activities played a critical role in deciding the composition and distribution of VOCs in the sediment. This study also shows that the proportion of VOCs in halite was discernably higher than that in clay and sandstone and that the content of VOCs should be considered when studying OM in salt lake sediments.

scholarly journals A MEMS µ-Preconcentrator Employing a Carbon Molecular Sieve Membrane for Highly Volatile Organic Compound Sampling

Chemosensors ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 104
Author(s):  
Hung-Yang Kuo ◽  
Wei-Riu Cheng ◽  
Tzu-Heng Wu ◽  
Horn-Jiunn Sheen ◽  
Chih-Chia Wang ◽  
...  
Keyword(s):  
Organic Compound ◽  
Organic Compounds ◽  
Volatile Organic Compound ◽  
Molecular Sieve ◽  
Amplification Factor ◽  
Microfluidic Channel ◽  
Carbon Molecular Sieve ◽  
Volatile Organic ◽  
Chromatographic Peaks ◽  
Gaseous Toluene

This paper presents the synthesis and evaluation of a carbon molecular sieve membrane (CMSM) grown inside a MEMS-fabricated μ-preconcentrator for sampling highly volatile organic compounds. An array of µ-pillars measuring 100 µm in diameter and 250 µm in height were fabricated inside a microfluidic channel to increase the attaching surface for the CMSM. The surface area of the CMSM was measured as high as 899 m2/g. A GC peak amplification factor >2 × 104 was demonstrated with gaseous ethyl acetate. Up to 1.4 L of gaseous ethanol at the 100 ppb level could be concentrated without exceeding the capacity of this microchip device. Sharp desorption chromatographic peaks (<3.5 s) were obtained while using this device directly as a GC injector. Less volatile compounds such as gaseous toluene, m-xylene, and mesitylene appeared to be adsorbed strongly on CMSM, showing a memory effect. Sampling parameters such as sample volatilities, sampling capacities, and compound residual issues were empirically determined and discussed.

Volatile organic compounds sources in Paris in spring 2007. Part II: source apportionment using positive matrix factorisation

2011 ◽  
Vol 8 (1) ◽  
pp. 91 ◽  
Author(s):  
Cécile Gaimoz ◽  
Stéphane Sauvage ◽  
Valérie Gros ◽  
Frank Herrmann ◽  
Jonathan Williams ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compound ◽  
Organic Compounds ◽  
Emission Inventory ◽  
Positive Matrix ◽  
Air Mass ◽  
Volatile Organic ◽  
Industrial Sources ◽  
Fuel Evaporation ◽  
Matrix Factorisation

Environmental context Volatile organic compounds are key compounds in atmospheric chemistry as precursors of ozone and secondary organic aerosols. To determine their impact at a megacity scale, a first important step is to characterise their sources. We present an estimate of volatile organic compound sources in Paris based on a combination of measurements and model results. The data suggest that the current emission inventory strongly overestimates the volatile organic compounds emitted from solvent industries, and thus needs to be corrected. Abstract A positive matrix factorisation model has been used for the determination of volatile organic compound (VOC) source contributions in Paris during an intensive campaign (May–June 2007). The major sources were traffic-related emissions (vehicle exhaust, 22% of the total mixing ratio of the measured VOCs, and fuel evaporation, 17%), with the remaining emissions from remote industrial sources (35%), natural gas and background (13%), local sources (7%), biogenic and fuel evaporation (5%) and wood-burning (2%). It was noted that the remote industrial contribution was highly dependent on the air-mass origin. During the period of oceanic influences (when only local and regional pollution was observed), this source made a relatively low contribution (<15%), whereas the source contribution linked to traffic was high (54%). During the period of continental influences (when additional continental pollution was observed), remote industrial sources played a dominant role, contributing up to 50% of measured VOCs. Finally, the positive matrix factorisation results obtained during the oceanic air mass-influenced period were compared with the local emission inventory. This comparison suggests that the VOC emission from solvent industries might be overestimated in the inventory, consistent with findings in other European cities.

scholarly journals Volatile organic compound signature from co-culture of lung epithelial cell line with Pseudomonas aeruginosa

The Analyst ◽  
2018 ◽  
Vol 143 (13) ◽  
pp. 3148-3155 ◽  
Author(s):  
Oluwasola Lawal ◽  
Hugo Knobel ◽  
Hans Weda ◽  
Lieuwe D. Bos ◽  
Tamara M. E. Nijsen ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Volatile Organic Compounds ◽  
Organic Compound ◽  
Epithelial Cell ◽  
Organic Compounds ◽  
Volatile Organic Compound ◽  
Epithelial Cell Line ◽  
Diagnostic Biomarkers ◽  
Lung Epithelial ◽  
Volatile Organic

Bacterial volatile organic compounds have the potential to be utilised as diagnostic biomarkers for infections.

scholarly journals Mid-IR evanescent-field fiber sensor with enhanced sensitivity for volatile organic compounds

RSC Advances ◽  
2019 ◽  
Vol 9 (37) ◽  
pp. 21186-21191 ◽  
Author(s):  
Farah Alimagham ◽  
Max Platkov ◽  
Joshua Prestage ◽  
Svetlana Basov ◽  
Gregory Izakson ◽  
...  
Keyword(s):  
Organic Compound ◽  
Gas Phase ◽  
Organic Compounds ◽  
Volatile Organic Compound ◽  
Evanescent Field ◽  
Fiber Sensor ◽  
Porous Coating ◽  
Enhanced Sensitivity ◽  
Volatile Organic ◽  
Increased Sensitivity

Increased sensitivity of mid-IR evanescent field sensing for gas-phase volatile organic compound detection using a nano-porous coating of an optical-fibre.

Review of Distribution Characteristics and Sources of Volatile Organic Compound in Atmosphere

2013 ◽  
Vol 726-731 ◽  
pp. 944-949
Author(s):  
Zhen Hua Xiong ◽  
Feng Qian ◽  
Xue Feng ◽  
Rong Rong Su ◽  
Yu Zeng
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compound ◽  
Human Health ◽  
Organic Compounds ◽  
Volatile Organic Compound ◽  
Distribution Characteristics ◽  
Sources Apportionment ◽  
Secondary Pollutants ◽  
Volatile Organic ◽  
Many Sources

Volatile Organic Compounds (VOCs) have many sources, and they have effects on ecology and human health, which has aroused extensive attentions of many researchers. The Chinese and other countries studies in VOCs in atmosphere focused on detecting concentrations and compositions, sources apportionment, secondary pollutants transformation, health effects and other aspects. In the present paper, VOCs level in atmosphere, distribution characteristics and sources apportionment of VOCs in atmosphere were reviewed, the current studies results of VOCs in atmosphere were summarized.

Snow - a photobiochemical exchange platform for volatile and semi-volatile organic compounds with the atmosphere

2011 ◽  
Vol 8 (1) ◽  
pp. 62 ◽  
Author(s):  
P. A. Ariya ◽  
F. Domine ◽  
G. Kos ◽  
M. Amyot ◽  
V. Côté ◽  
...  
Keyword(s):  
Climate Change ◽  
Organic Matter ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Chemical Species ◽  
The Arctic ◽  
Exchange Processes ◽  
Colony Forming Units ◽  
Volatile Organic

Environmental context Recent research has been directed towards the exchange of microorganisms and chemical compounds between snow and air. We investigate how microorganisms and chemical species in snow from the Arctic and temperate regions are transferred to the atmosphere and altered by the sun's energy. Results suggest that snow photo-biochemical reactions, in addition to physical‐chemical reactions, should be considered in describing organic matter in air–snow exchanges, and in investigations of climate change. AbstractField and laboratory studies of organic compounds in snow (12 species; concentrations ≤17 µg L–1) were conducted and microorganisms in snow and aerosols at urban and Arctic sites were investigated (snow: total bacteria count ≤40000 colony forming units per millilitre (CFU mL–1), fungi ≤400 CFU mL–1; air: bacteria ≤2.2 × 107 CFU m–3, fungi ≤84 CFU m–3). Bio-organic material is transferred between snow and air and influence on snow-air exchange processes is demonstrated. Volatile organic compounds in snow are released into the air upon melting. In vitro photochemistry indicated an increase of ≤60 µg L–1 for 1,3- and 1,4-dimethylbenzenes. Bacillus cereus was identified and observed in snow and air with ice-nucleating being P. syringae absent. As a result snow photobiochemical reactions should be considered in describing organic matter air–snow exchanges, and the investigation of climate change.

scholarly journals Evaluating In Silico the Potential Health and Environmental Benefits of Houseplant Volatile Organic Compounds for an Emerging ‘Indoor Forest Bathing’ Approach

2021 ◽  
Vol 19 (1) ◽  
pp. 273
Author(s):  
Valentina Roviello ◽  
Pasqualina Liana Scognamiglio ◽  
Ugo Caruso ◽  
Caterina Vicidomini ◽  
Giovanni N. Roviello
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compound ◽  
Organic Compounds ◽  
In Silico ◽  
Health Benefits ◽  
Biogenic Volatile Organic Compounds ◽  
Potential Health ◽  
Forest Bathing ◽  
In Silico Studies ◽  
Volatile Organic

The practice of spending time in green areas to gain the health benefits provided by trees is well known, especially in Asia, as ‘forest bathing’, and the consequent protective and experimentally detectable effects on the human body have been linked to the biogenic volatile organic compounds released by plants. Houseplants are common in houses over the globe and are particularly appreciated for aesthetic reasons as well for their ability to purify air from some environmental volatile pollutants indoors. However, to the best of our knowledge, no attempt has been made to describe the health benefits achievable from houseplants thanks to the biogenic volatile organic compounds released, especially during the day, from some of them. Therefore, we performed the present study, based on both a literature analysis and in silico studies, to investigate whether the volatile compounds and aerosol constituents emitted by some of the most common houseplants (such as peace lily plant, Spathiphyllum wallisii, and iron plant, Aspidistra eliator) could be exploited in ‘indoor forest bathing’ approaches, as proposed here for the first time not only in private houses but also public spaces, such as offices, hospitals, and schools. By using molecular docking (MD) and other in silico methodologies for estimating vapor pressures and chemico-physical/pharmacokinetic properties prediction, we found that β-costol is an organic compound, emitted in appreciable amounts by the houseplant Spathiphyllum wallisii, endowed with potential antiviral properties as emerged by our MD calculations in a SARS-CoV-2 Mpro (main protease) inhibition study, together with sesquirosefuran. Our studies suggest that the anti-COVID-19 potential of these houseplant-emitted compounds is comparable or even higher than known Mpro inhibitors, such as eugenol, and sustain the utility of houseplants as indoor biogenic volatile organic compound emitters for immunity boosting and health protection.

Investigation of indoor total volatile organic compound concentrations in densely occupied university buildings under natural ventilation: Temporal variation, correlation and source contribution

2020 ◽  
pp. 1420326X2091400
Author(s):  
Yabin Jia ◽  
Xu Zheng ◽  
Jun Guan ◽  
Xue Tan ◽  
Shuqin Chen ◽  
...  
Keyword(s):  
Organic Compound ◽  
Temporal Variation ◽  
Volatile Organic Compound ◽  
Natural Ventilation ◽  
Impact Analysis ◽  
Strong Positive Correlation ◽  
Total Volatile ◽  
Indoor Sources ◽  
Volatile Organic ◽  
Indoor And Outdoor

Human activities have been proven to be one of the most important sources of indoor volatile organic compound (VOC) emissions, especially in densely occupied environments. However, characterization of temporal variation and its impact analysis of indoor total volatile organic compounds (TVOC) have not been presented adequately. In this study, indoor concentrations and temporal variation of TVOC concentrations were investigated using a continuous monitoring instrument in 20 densely occupied education buildings randomly selected at one university in Nanjing, China, including nine lecture halls and 11 classrooms. Indoor and outdoor CO2 concentration, temperature and relative humidity were monitored to analyse the correlation and contribution rates of TVOC from indoor and outdoor sources. Results show that the variation in the indoor TVOC concentration was similar to the indoor CO2 concentration in densely occupied education buildings with the exception of sudden indoor sources, such as food service. Further analysis indicates that a strong positive correlation was observed between the number of occupants and TVOC concentrations. The average contribution rate could reach 69.2% from indoor sources and 30.8% from outdoors. This study provided a better understanding of the status quo and could help in developing control strategies of indoor air quality in densely occupied education buildings.

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