Kinds Of Volatile Organic Compounds Research Articles

Sector instruments for chemical analysis and research

When the last chemical elements were successfully measured by mass spectrometry its use for the characterisation of isotopes declined, but its use for chemical analysis and research grew. This new field of activity was aided by the emergence of commercially manufactured sector mass spectrometers designed for the analysis of oil refinery gases. Although the 1940s saw the use of mass spectrometry dominated by the petroleum industry it also saw many developments in its application to chemical analysis. By the early 1950s heated inlet systems were allowing spectra of all kinds of volatile organic compounds to be obtained. The 1950s saw the development of accurate mass measurement of organic molecules as a means of determining their elemental composition. This led to a demand for higher resolution double focusing instruments. Two types of design competed for this application, each with their perceived advantages and disadvantages. It was another decade, following the application of computers to high throughput accurate mass measurement, before one of these came to dominate. Double focusing sector instruments also enhance the information afforded by “metastable” ions, allowing identification of precursor and product ions. This led to the developments of Collision Induced Decompositions, MIKES and “linked scans”. The mass range demanded of mass spectrometers jumped to new levels with the development of Fast Atom Bombardment (FAB). This led to new sector designs incorporating innovative new magnets. The success of FAB as a soft ionisation technique meant it produced little fragmentation and structural information. This led to a growth in the use of tandem MS/MS instrumentation as a tool for determining structures. This paper recounts these and many other developments which kept magnetic sectors at the centre of major new developments in mass spectrometry for chemical analysis and research for so long.

The Method Study on Emergency Detection of Aromatic Compounds and Chlorides based on Portable GC-MS

In order to quickly identify the kinds of volatile organic compounds(VOCs) and quantified their concentrations, a method based on portable GC−MS was developed, which was especially suitable for the detection of aromatic compounds and chlorides. The mixed gases were directly collected by solid phase microextraction head for 120seconds. After that, they were analyzed on the portable GC-MS, identified by retention time and MS peaks, quantified by external standard method. It only took 6.4min from sampling to get the result. The linear correlation was larger than 0.98, and the minimum detectable concentration was lower than half of their occupational exposure limits, respectively. In the simulation test, the relative error was lower than 4.4%. This method can directly collect the air sample in the field, rarely depends on external conditions, and is very convenient to carry out. It takes very short time to complete the detection, at the same time it can identify and quantify multiple kinds of gases at a time. So this method is quite suitable for the emergency detection at the gas leak site.

Effects of subchronic exposure to low‐dose volatile organic compounds on lung inflammation in mice

Inflammatory lung diseases are characterized by chronic inflammation and oxidant/antioxidant imbalance. Exposure to some kinds of volatile organic compounds (VOCs) leads to lung inflammation, oxidative stress, and immune modulation. However, it is suspected that sub-chronic exposure to low-dose VOCs mixture induces or aggravates lung inflammation. To clarify the effect of this exposure on lung inflammatory responses, 40 male Kunming mice were exposed in four similar static chambers, 0 (control) and three different doses of VOCs mixture (groups 1-3). The concentrations of VOCs mixture were as follows: formaldehyde, benzene, toluene, and xylene 0.10 + 0.11 + 0.20 + 0.20 mg/m(3) , 0.50 + 0.55 + 1.00 + 1.00 mg/m(3) , 1.00 + 1.10 + 2.00 + 2.00 mg/m(3) , respectively, which corresponded to 1, 5, and 10 times of indoor air quality standard in China. After 90 consecutive days of exposure (2 h/day), oxidative stress markers in lung, cellular infiltration and cytokines, chemokine, neurotrophin in bronchoalveolar lavage fluid (BALF), and immunoglobulin (Ig) in serum were examined. VOCs exposure could increase significantly reactive oxygen species (ROS) in lung, the levels of interleukin-8 (IL-8), IL-4, eotaxin, nerve growth factor (NGF), and various types of leukocytes in BALF, IgE concentration in serum. In contrast, GSH to GSSG ratio and interferon-gamma were significantly decreased following the VOCs exposure. These results indicate that the VOCs mixture-induced inflammatory response is at least partly caused by release of the ROS and mediators from the activated eosinophils, neutrophils, alveolar macrophages and epithelial cells.

Antifungal activity of volatile organic compounds fromStreptomyces alboflavusTD-1

Streptomyces sp. TD-1 was identified as Streptomyces alboflavus based on its morphological characteristics, physiological properties, and 16S rDNA gene sequence analysis. The antifungal activity of the volatile-producing S. alboflavus TD-1 was investigated. Results showed that volatiles generated by S. alboflavus TD-1 inhibited storage fungi Fusarium moniliforme Sheldon, Aspergillus flavus, Aspergillus ochraceus, Aspergillus niger, and Penicillum citrinum in vitro. GC/MS analysis revealed that 27 kinds of volatile organic compounds were identified from the volatiles of S. alboflavus TD-1 mycelia, among which the most abundant compound was 2-methylisoborneol. Dimethyl disulfide was proved to have antifungal activity against F. moniliforme by fumigation in vitro.

Consequences of cavity size and chemical environment on the adsorption properties of isoreticular metal-organic frameworks: An inverse gas chromatography study

The role of the structure of three isoreticular metal-organic frameworks (IRMOFs) on their adsorption behavior has been studied in this work, selecting different kinds of volatile organic compounds (VOCs) as adsorbates (alkanes, alkenes, cycloalkanes, aromatics and chlorinated). For this purpose, three samples (IRMOF-1, IRMOF-8 and IRMOF-10) with cubic structure and without functionalities on the organic linkers were synthesized. Adsorption capacities at infinite dilution were derived from the adsorption isotherms, whereas thermodynamic properties have been determined from chromatographic retention volume. The capacity and the strength of adsorption were strongly influenced by the adsorbate size. This effect is especially relevant for n-alkanes adsorption, indicating the key role of the cavity size on this phenomenon, and hence the importance of the IRMOF structural properties. A different behavior has been observed for the polar compounds, where an enhancement on the specificity of the adsorption with the π-electron rich regions was observed. This fact suggests the specific interaction of these molecules with the organic linkers of the IRMOFs.

The Research of Gas-Sensing and Optical Characterization of Chlorinated Metallic Porphyrin Spin-Coated Films

In this text, the Chlorinated metallic porphyrin (TPPMncl and TPPFecl) thin films were fabricated by Spin-coated technique onto quartz substrates. In order to search for the gas-sensing characterization of Chlorinated metallic porphyrin Spin-coated films, the changes of UV-Visible absorption spectrums of TPPMncl and TPPFecl Spin-coated films respectively exposed in vapor of Chloroform, pyridine, Ammonia, triethylamine and dimethylamine were analyzed. The experimental results show that, the spectral response of TPPMncl and TPPFecl on organic gas molecular is obviously found. And we know that chlorinated metallic porphyrin film formed the J-aggregates. Moreover, through two kinds of chlorinated metallic porphyrin integral area rate of histogram, it is easy to identify and distinguish between the four kinds of volatile organic compounds. It indicates that these Chlorinated metallic porphyrin have gasochromic characteristics while responding with organic gas. Therefore, these materials can be prepared into gas sensor array for detecting VOCS.

Quantitative analysis of different volatile organic compounds using an improved electronic nose

This paper sets up an improved electronic nose with an automatic sampling mode, large volumetric vapors and constant temperature for headspace vapors and gas sensor array. In order to facilitate the fast recovery and good repeatability of gas sensors, the steps taken include (A) short-time contact with odors measured; (B) long-time purification using environmental air; (C) exact calibration using clean air before sampling. We employ multiple single-output perceptrons to discriminate and quantify multiple kinds of odors. This task is first regarded as multiple two-class discrimination problems and then multiple quantification problems, and accomplished by multiple single-output perceptrons followed by multiple single-output perceptrons. The experimental results for measuring and quantifying 12 kinds of volatile organic compounds with changing concentrations show that the type of electronic nose with a hierarchical perceptron model has a simple structure, easy operation, good repeatability and good discrimination and quantification performance.

The removal of styrene using a dielectric barrier discharge (DBD) reactor and the analysis of the by-products and intermediates

As a kind of volatile organic compound, styrene is a typical industrial pollutant with high toxicity and odorous smell. In this study, the removal of malodorous styrene simulation waste gas was carried out in a self-made wire-tube dielectric barrier discharge reactor. The decomposition efficiency of the reaction was investigated under different applied voltages and flow rates. The results showed that nearly 99.6 % of styrene could be removed with a concentration of 3,600 mg/m3 and the applied voltage of 10.8 kV. However, the selectivity of CO2 and CO showed that the mineralization efficiency of styrene was less than 25 %. The by-products of the reaction, including O3, NO x and other intermediates, were also detected and analyzed under different applied voltages. The relationships between the applied voltage and the quantity of final product (CO2) and by-products (intermediate organics, NO x , O3) were investigated. The reaction mechanism was also described according to the bond energy and the intermediates that formed.

Performance evaluation of multilayer perceptrons for discriminating and quantifying multiple kinds of odors with an electronic nose

This paper studies several types and arrangements of perceptron modules to discriminate and quantify multiple odors with an electronic nose. We evaluate the following types of multilayer perceptron. (A) A single multi-output (SMO) perceptron both for discrimination and for quantification. (B) An SMO perceptron for discrimination followed by multiple multi-output (MMO) perceptrons for quantification. (C) An SMO perceptron for discrimination followed by multiple single-output (MSO) perceptrons for quantification. (D) MSO perceptrons for discrimination followed by MSO perceptrons for quantification, called the MSO-MSO perceptron model, under the following conditions: (D1) using a simple one-against-all (OAA) decomposition method; (D2) adopting a simple OAA decomposition method and virtual balance step; and (D3) employing a local OAA decomposition method, virtual balance step and local generalization strategy all together. The experimental results for 12 kinds of volatile organic compounds at 85 concentration levels in the training set and 155 concentration levels in the test set show that the MSO-MSO perceptron model with the D3 learning procedure is the most effective of those tested for discrimination and quantification of many kinds of odors.

The atmospheric chemistry of trace gases and particulate matter emitted by different land uses in Borneo

We report measurements of atmospheric composition over a tropical rainforest and over a nearby oil palm plantation in Sabah, Borneo. The primary vegetation in each of the two landscapes emits very different amounts and kinds of volatile organic compounds (VOCs), resulting in distinctive VOC fingerprints in the atmospheric boundary layer for both landscapes. VOCs over the Borneo rainforest are dominated by isoprene and its oxidation products, with a significant additional contribution from monoterpenes. Rather than consuming the main atmospheric oxidant, OH, these high concentrations of VOCs appear to maintain OH, as has been observed previously over Amazonia. The boundary-layer characteristics and mixing ratios of VOCs observed over the Borneo rainforest are different to those measured previously over Amazonia. Compared with the Bornean rainforest, air over the oil palm plantation contains much more isoprene, monoterpenes are relatively less important, and the flower scent, estragole, is prominent. Concentrations of nitrogen oxides are greater above the agro-industrial oil palm landscape than over the rainforest, and this leads to changes in some secondary pollutant mixing ratios (but not, currently, differences in ozone). Secondary organic aerosol over both landscapes shows a significant contribution from isoprene. Primary biological aerosol dominates the super-micrometre aerosol over the rainforest and is likely to be sensitive to land-use change, since the fungal source of the bioaerosol is closely linked to above-ground biodiversity.

Quantitative analysis of multiple kinds of volatile organic compounds using hierarchical models with an electronic nose

This paper studies hierarchical discrimination and quantification models in order to simultaneously quantify multiple kinds of odors with an improved electronic nose. Such tasks are first regard as multiple discrimination tasks and then as multiple quantification tasks, and implemented by the hierarchical models with the divide-and-conquer strategy. The discrimination models are the common classifiers, including nearest neighbor classifiers, local Euclidean distance templates, local Mahalanobis distance templates, multi-layer perceptrons (MLPs), support vector machines (SVMs) with Gaussian or polynomial kernels. Similarly, the quantification models are multivariate linear regressions, partial least squares regressions, multivariate quadratic regressions, MLPs, SVMs. We developed several types of hierarchical model and compared their capabilities for quantifying 12 kinds of volatile organic compounds with the improved electronic nose. The experimental results show that the hierarchical model composed of multiple single-output MLPs followed by multiple single-output MLPs with local decomposition, virtual balance and local generalization techniques, has advantages over the others in the aspects of time complexity, structure complexity and generalization performance.

Determination of Three Kinds of Volatile Residue of Ozone-Depleting Substances in Polyurethane Foam by Gas Chromatography

This paper developed a gas chromatography for the determination of volatile residue of ozone-depleting substances (OSD) in polyurethane foam. The sample was detected by gas chromatography - electron capture detector (GC-ECD) under the condition of 120 oC, 5 oC of condensing reflux temperature, 30 min of extraction time and external standard method for quantification. The experimental results of spike recovery showed that: the average recovery of residue of Trichloromonofluoromethane, difluoromonochloroethane and 1, 1, 2 - trifluoro -1, 2, 2 – trichloroethane, the three volatile organic solvent, was 72.7% ~ 116.1%, and the relative standard deviations were less than 5%. This method can effectively overcome the matrix interference, and one introduction of samples can separate and detect three kinds of volatile organic compounds in polyurethane, which has the characteristics of wide linear range and short response time and improves the analytical efficiency.

Fast screening for presence of muddy/earthy odorants in wine and in wine must using a hyphenated gas chromatography-differential ion mobility spectrometry (GC/DMS)

Rapid, hyphenated detection techniques involving a gas chromatograph (GC) coupled to a classical time-of-flight ion mobility (IMS) spectrometer, or more recently, to a micro-machined, miniature differential ion mobility spectrometer (DMS) are quite attractive for in-situ detection of many kinds of volatile organic compounds (VOCs) of concern and notably of natural contaminants appearing in the headspaces of selected foodstuff. This work aims at a rapid detection, identification and quantification of geosmin in the headspace of grape must and of wine. Samples of white and red wines have both been analyzed with a hyphenated GC/DMS and by Solid Phase Micro-Extraction (SPME) coupled to GC/MS taken as a reference. The detection of geosmin at concentrations below the human olfactory threshold of 50 ng/L has been demonstrated.

Elimination of NH3 and odor from composting by biotrickling filter and preliminary exploration on molecular biology

A biotrickling filter was focused on treatment of odorous NH(3) gas, along with volatile organic compounds (VOCs) and other odorous gases during cattle manure composting. The biotrickling filter could treat NH(3), the main composition, with removal efficiencies of close to 100% because NH(4)(+) was bio-oxidized in the biofilm to NO(3)(-) resulting final NO(3)(-) concentrations of about 1000 mg/L. Results of polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) revealed that ammonia-oxidizing bacteria, Nitrosospira sp, and nitrite-oxidizing bacteria, Nitrococcus mobilis, coexisted in the biofilm. There were 23 kinds of VOCs detected in the exhaust gas. A significant observation was that the biofilm itself of the biotrickling biofilter released VOCs. The odor concentrations of inlet and outlet gases were 1425 and 110, respectively, with removal efficiency of 92.2%, suggesting that the biotrickling filter was effective for treatment of odorous gases during composting.

Total OH reactivity and VOC analyses for gasoline vehicular exhaust with a chassis dynamometer

Total OH reactivity for the exhaust gas of gasoline vehicles was measured for the first time under nine different driving conditions with a chassis dynamometer at the National Institute for Environmental Studies (NIES). Along with the total OH reactivity measurements, analysis of trace species such as CH 4, CO, NO, NO 2, and 56 kinds of volatile organic compounds (VOCs), including two aldehydes, was carried out. The ratio of alkanes to alkenes in the exhaust gas turned out to depend on the condition of the driving cycles. There were a considerable number of unidentified peaks obtained during GC analysis. About 15–30% of the total carbon was unidentified species. The chemical compositions of vehicular exhaust were found to depend on the temperature of the engine or catalysts. The contribution of OH reactivity to the species obtained depended on the temperature condition for the engine. The calculated total OH reactivity for VOCs was compared with ozone formation potential (OFP) and it turned out that there are in good correlation, while the correlation for “Cold” start deviates from that for “Hot” start. The measured and calculated OH reactivities were compared with each other. For all driving cycles, the calculated OH reactivity was confirmed to be an underestimation, implying the existence of unknown species in the exhaust gas. The percentage contribution of OH reactivity to the unknown species during “Cold” start was about 17.5%, which was almost the same as that for “Hot” start at 17.0%. However, the absolute value of OH reactivity for “Cold” start was about ten times higher than that for “Hot” start.

Supramolecular Assembly of Perylene Bisimide with β‐Cyclodextrin Grafts as a Solid‐State Fluorescence Sensor for Vapor Detection

AbstractA nanoscopic supramolecular aggregate is constructed from perylene bisimide‐bridged bis‐(permethyl‐β‐cyclodextrins) 1 via π–π stacking interactions. Its self‐assembly behavior in organic and aqueous solutions is investigated by UV–Vis, fluorescence, and 1H NMR spectroscopy. Transmission electron microscopy and scanning electron microscopy images show the 1D nanorod aggregation of 1, which is birefringent under crossed polarizer conditions and strongly fluorescent as depicted in the fluorescence microscopy image. X‐ray powder diffraction measurements indicate that 1 forms a well‐ordered crystalline arrangement with a π–π stacking distance of 4.02 Å. Furthermore, the solid‐state fluorescence sensing is explored by utilizing the poly(vinylidene fluoride) membrane‐embedded 1, giving that 1, as a novel vapor detecting material, can probe several kinds of volatile organic compounds and, especially, exhibits high sensitivity to organic amines.

容器包装プラスチックの圧縮梱包施設における化学物質の排出実態

Chemicals that were discharged from a compactor for used plastic containers and packages regulated by Japanese Law for the Promotion of Sorted Collection and Recycling of Containers and Packages, were measured in seasonally for one year at 3 medium-scale facilities. Among 39 kinds of volatile organic compounds (VOC) measured, chloromethane, 1,3-butadiene and styrene were detected at high concentrations, because chloromethane is used as foaming additive for plastics, styrene and 1,3-butadiene are raw materials for polystyrene (PS) and high-impact PS (HIPS). Detected concentrations of diethyl phthalate (DEP), di-n-butyl phthalate (DBP), bis-2-ethylhexyl adipate (DEHA) and bis-2-ethylhexyl phthalate(DEHP) in front of the compactor device were 2 to 120 times higher than the concentrations at the site boundary. However, 24-hour monitoring concentrations of VOC and phthalates at a site boundary went within the range of monitoring results of hazardous air pollutants measured by several local public bodies.

Dilute TCE Decomposition by the Nonthermal Plasma Combined with MnO2-supported Alumina

Atmospheric pressure nonthermal plasma has very high chemical reactivity and can decompose various toxic materials. The authors are engaged in decomposing the various kinds of VOCs (volatile organic compounds) by using the nonthermal plasma (typically barrier discharge reactor). To improve the energy efficiency, modification of the plasma reactor has been done. A new catalyst, manganese dioxide—supported alumina sphere of 3 mm in diameter was manufactured by ourselves for the combined process with the plasma. That can decompose the ozone very well, where the ozone is one of the typical byproducts produced by the strong barrier discharge in the air. At that ozone decomposition process, dilute TCE (trichloroethylene) is also oxidized very well. The ozone decomposition generates single atomic oxygen which oxidizes TCE very well. The total performance of that alumina assisted plasma process is investigated. The specific energy density (SED) is only 10 J/L when the TCE decomposition efficiency is more than 99 % which is the least record in our experiments. Moreover, the carbon balance from TCE to carbon oxide is also more than 90 % at the SED of 90 J/L.

Removal of dichloromethane from waste gases with a bio-contact oxidation reactor

Dichloromethane (DCM) is a kind of volatile organic compound (VOC), and many biological technologies have been studied and applied to meet the treatment of the waste gases. In this paper, a new bio-contact oxidation reactor, in which biofilm attached on the assembly semi-soft plastic media filled in column, was set up to removal DCM from waste gases. The influences of empty bed residence time (EBRT), temperature, pH and organic load on the removal efficiency (RE) and the elimination capacity (EC) of DCM were investigated and discussed. The optimum operation conditions were obtained as the temperature of 20–30 °C, pH 6.0–7.0 and EBRT of 28.3 s for the inlet gas concentration range of 500–1260 mg/m3. Under the optimum operation conditions, the average removal efficiency of DCM was higher than 82%, at the inlet concentration of DCM lower than 1260 mg/m3. The maximum elimination capacity (ECmax) of DCM in the bio-contact reactor was higher than that in the biofilters reported in the literature under the same operation conditions.

Removal of toluene from air streams using a gas–liquid–solid three‐phase airlift loop bioreactor containing immobilized cells

AbstractToluene, a kind of volatile organic compound (VOC), is widely used as a solvent (paints and coatings, gums, resins, rubber) as well as a reagent (medicines, dyes, perfumes) and is one of the components of gasoline. Over the more recent decades, many studies have led to the development of biological methods to treat toluene. This paper presents the results of a study on the treatment of airborne toluene using a laboratory‐scale gas–liquid–solid three‐phase airlift loop bioreactor containing immobilized cells. Based on the optimum operating conditions such as the temperature of 28–30 °C, pH of 7.0–7.2, and an empty bed residence time (EBRT) of 39.6 s, a continuous bioprocess showed that this immobilized airlift loop bioreactor had a steady‐state performance within 15 days, the outlet concentrations of toluene were lower than the national emission standard in China (GB 16297‐1996), and the chemical oxygen demand and NH4+‐N of the effluent also satisfied the primary discharge standard in China (GB 8978‐1996). In addition, this immobilized airlift loop bioreactor had a good ability to tolerate shock loads, while the maximum elimination capacity of toluene was 168 g m−3 h−1 which was higher than those not only in biofilters and biotrickling filters but also in the airlift bioreactor with free microorganisms. Copyright © 2005 Society of Chemical Industry