Organic Compounds In Ambient Air Research Articles

Monitoring volatile organic compounds in ambient air inside and outside buildings with the use of a radio‐frequency‐based ion‐mobility analyzer with a micromachined drift tube

Monitoring volatile organic compounds in ambient air inside and outside buildings with the use of a radio‐frequency‐based ion‐mobility analyzer with a micromachined drift tube

A sensitive diffusion sampler for the determination of volatile organic compounds in ambient air

We developed a diffusive sampling device (DSD-voc) for volatile organic compounds (VOCs) which is suitable for collection of low level VOCs and analysis with thermal desorption. This sampling device is composed of two parts, an exposure part made of a porous polytetrafluoroethylene (PTFE) filter, and an analysis part made of stainless-steel tubing. The DSD-voc collects VOCs through the mechanism of molecular diffusion. Collection is controlled by moving the adsorbent from the exposure part to the analysis part by changing the posture of the DSD-voc. Adsorbates in the DSD-voc were analyzed by GC/MS with a thermal desorption cold trap injector (TCT). The TCT has the advantage of being able to accept the entire quantity of VOCs. We connected a condenser between the DSD-voc and the trap tube to prevent moisture from freezing in the trap tube when the sampler was packed with strong adsorbent. We also examined the desorption efficiency for VOCs from several types of adsorbents (Carboxen TM 1000, Carbosieve TM G, Carbosieve S III, Carbotrap TM B, and activated carbon) over a wide range of temperatures. Carboxen 1000 was suitable for the determination of VOCs with a low boiling point range, from CFC12 to hexane, while Carbotrap B was suitable for VOCs from hexane to 1,4-dichlorobenzene. The limits of detection with Carboxen 1000 and Carbotrap B were 0.036–0.046 and 0.0035–0.014 ppb, respectively, for a sampling duration of 24 h. Coefficients of variation for concentrations of major VOCs ranged from 3.8 to 14%. It is possible to estimate atmospheric VOCs at sub-parts per billion (sub-ppb), with high sensitivity, by using both adsorbents in combination.

Determination of a Wide Range of Volatile Organic Compounds in Ambient Air Using Multisorbent Adsorption/Thermal Desorption and Gas Chromatography/Mass Spectrometry

Adsorption/thermal desorption with multisorbent air-sampling cartridges was developed for the determination of 87 method analytes including halogenated alkanes, halogenated alkenes, ethers, alcohols, nitriles, esters, ketones, aromatics, a disulfide, and a furan. The volatilities of the compounds ranged from that of dichlorofluoromethane (CFC12) to that of 1,2,3-trichlorobenzene. The eight most volatile compounds were determined using a 1.5-L air sample and a sample cartridge containing 50 mg of Carbotrap B and 280 mg of Carboxen 1000; the remaining 79 compounds were determined using a 5-L air sample and a cartridge containing 180 mg of Carbotrap B and 70 mg of Carboxen 1000. Analysis and detection were by gas chromatography/mass spectrometry. The minimum detectable level (MDL) concentration values ranged from 0.01 parts per billion by volume (ppbv) for chlorobenzene to 0.4 ppbv for bromomethane; most of the MDL values were in the range 0.02−0.06 ppbv. No breakthrough was detected with the prescribed samp...

The influence of localized emittants on the concentration of volatile organic compounds in the ambient air measured close to ground level

As part of an investigation into the relationship of volatile organic compounds in ambient air and a nearby refinery, a risk assessment was performed as well as an analysis of the attribution of each source contributing to the emission of pollutants. The compounds under consideration being the alkanes, chlorinated hydrocarbons, aromatics, and aldehydes. Taking into account the sources (refinery and/or traffic) and the possible source-attributable pollutant combinations, locally dependent pollution profiles were observed. While aromatics and aldehydes were distributed relatively uniformly, the combination aromatics and alkanes at several localities pointed clearly to the refinery as the source of the pollution. An analysis of the indoor measurements at a school close to the refinery demonstrated the necessity of identifying the source of the pollutants in order to be able to bring about environmental conditions acceptable to human health. © 1997 by John Wiley & Sons, Inc. Environ Toxicol Water Qual 12: 31–37, 1997

Technique for monitoring ozone precursor hydrocarbons in air at photochemical assessment monitoring stations: Sorbent preconcentration, closed-cycle cooler cryofocusing, and GC-FID analysis

An automated gas chromatograph (autoGC) system that may be used to collect and analyze both polar and nonpolar volatile organic compounds in ambient air has been evaluated. This system combines the use of dual multiadsorbent traps for sampling 57 min h −1 at ambient temperature, a dry helium purge to remove residual water from the sorbents, thermal desorption of analytes onto a Stirling-cooled trap for refocusing, and GC-flame ionization detection (FID). Method detection limits (MDLs), linearity, cleanliness, precision, and accuracy of the autoGC were determined for a set of 57 ozone precursor hydrocarbons. For most of the compounds tested, MDLs were less than 0.40 ppbv, the FID response was linear over the 5–40-ppbv range, and the trap-to-trap precision was ± 10%. This autoGC was found to be a reliable system that would be suitable for use in field sites such as the Photochemical Assessment Monitoring Stations network, which is being implemented in the United States of America.

Superfund contract laboratory program method evaluation — ambient air volatile organic compounds from canisters

A GC/MS system that is modified for the addition of internal standards has been used to run the Superfund method for volatile organic compounds in ambient air as described in the Statement of Work for the Superfund Contract Laboratory Program/Statement of Work (CLPSOW). The analysis method applies to air samples retrieved from GL (SUMMA-polished) stainless steel canisters. Generic performance criteria were tested by using full-scan mass spectrometry. The method quantitalion limit was determined to be less than the contract-required quantitation limit (CRQL) for 37 of the 41 target compounds; replicate analyses of field samples achieved CLP/SOW-specified values of precision (±25% difference relative to the average value for two analyses) for all target gas concentrations above the CRQLs; and audit accuracy values at a nominal 5-ppb v concentration averaged 9.6% unsigned average relative percentage difference. Field tests at the French Limited Superfund site near Crosby, Texas, support the choice of the scanning mode of mass spectrometer operation in that many nontargeted compounds occur at high concentrations. However, method quantitation limits for targeted compounds are increased by factors ranging from five to ten from those obtainable in the selected ion monitoring mode of mass spectrometer operation in that many nontargeted compounds occur at high concentrations. However, method quantitation limits for targeted compounds are increased by factors ranging from five to an from those obtainable in the selected ion monitoring mode

Build-up of artifacts on adsorbents during storage and its effect on passive sampling and gas chromatography-flame ionization detection of low concentrations of volatile organic compounds in air

The levels of blank artifacts on four adsorbents commonly used for air sampling (Tenax-TA, Tenax-GR, Carbotrap and Chromosorb 106) were observed to increase during storage. This may determine the detection limits and hence their suitability for the passive sampling of volatile organic compounds in ambient air. Blank build-up on Chromosorb 106 was very high. and this material cannot be used for passive sampling in ambient air. The blank build-up on Carbotrap was also high, especially in the Chromatographic range corresponding to hydrocarbons of ⩽C 5, but that on Tenax-TA and Tenax-GR was very low. Simultaneous sampling was carried out using different adsorbents, and for compounds that are the main artifacts on adsorbents (e.g., benzene on Tenax, benzene and toluene on Carbotrap) the results from Carbotrap are much higher than those from Tenax-TA and Tenax-GR, and the results from Tenax-TA and Tenax-GR also vary.

Hazardous wastes assessment, management, and minimization

Hazardous wastes assessment, management, and minimization

A sampling device for semivolatile organic compounds in ambient air

A filter/adsorbent sampler is presented which reduces handling problems and contamination risks associated with using XAD-resins as gas traps for semivolatile organic compounds. Since Soxhlet extraction is used in most routine analyses for SOC, the sampler employs a standard Soxhlet cartridge containing XAD. This allows adsorbent precleaning, air sampling and adsorbent extraction in one vessel without transfering the resin.

Method development and field measurements for polar volatile organic compounds in ambient air

The paper reports on a program which had two main objectives: (1) to develop an analytical method for polar volatile organic compounds (PVOCs) in ambient air using sample collection in canisters and (2) to perform PVOC analysis on ambient air samples collected at two sites formerly used in the U.S. EPA's Toxic Air Monitoring Study (TAMS). The analytical method consists of gas chromatographic separation of PVOCs with quantification by a quadrupole ion trap mass spectrometer. The PVOCs most often found in ambient samples include methanol, ethanol, acetone, 2-propanol, methyl ethyl ketone, and 1-butanol. Measured levels of these species often substantially exceed the levels of benzene and toluene present in the same samples. (Copyright (c) 1993 American Chemical Society.)

Testing of a sampling system and analytical method for determination of semivolatile organic compounds in ambient air

A sampling system and analytical procedure for determining PCDD/Fs, PCBs, HCB, and PAHs in ambient air was tested. The reproducibility of the concentrations and the gas/particle partitioning was ± 10% for most compounds. The removal of gaseous compounds on the XAD resin trap was greater than 99%. The adsorption of gaseous substances on the glass fiber filter was negligible for compounds primarily found in the gas phase, but could not be ruled out for compounds found mainly on particles.

Occurrence and vapor particle partitioning of heavy organic compounds in ambient air in Brazzaville, Congo

High volume air samples for organochlorine (OC) pesticides, polychlorinated biphenyls (PCB) and polycyclic aromatic hydrocarbons (PAH) were collected during August–September 1989 in Brazzaville, Congo (4·14°S, 15·14°E). Average concentrations (ng/m 3) were ΣDDT = 2·8; ΣHCH (hexachlorocyclohexane) 0·42; Σchlordane = 0.027; ΣPCB = 0.55; Σ3–6 ring PAH = 42; total DDT concentrations in Brazzaville fell between those reported in Porto Novo and Delhi (India) and were 20–100 times higher than those found in US cities. The average γ-HCH to α-HCH ratio (11) indicated use of lindane instead of technical HCH. The similarities between chlordane levels in Brazzaville and the open ocean indicated that little or no local use occurs. PAH levels were about equal to or lower than those reported in US cities, whereas PCB levels were three times lower. Vapor/particle distribution coefficients for several OC and PAH were in good correlation with their vapor pressures. The fraction of PAH on particles was greater than that of OC pesticides.

Optimizing Sensitivity of SIM Mode of GC/MS Analysis for EPA’s TO-14 Air Toxics Method

Guidelines for determining volatile organic compounds (VOCs) at ambient levels In air are published In Method TO-14 ol the U.S. Environmental Protection Agency’s “Compendium 01 Methods lor the Determination of Toxic Organic Compounds In Ambient Air.” To achieve the sensitivity required for sub-part-per-bllllon-by-volume (ppbv) determinations of VOCs, TO-14 recommends selective Ion monitoring (SIM) mode of operation when a conventional quadru-pole mass spectrometer Is used as the analytical finish. This paper describes the Implementation of SIM mode of analysis and presents the rationale and methods for optimizing SIM parameters for maximum sensitivity when analyzing whole-air samples for trace levels of targeted VOCs.

Sorbent-Based Method for the Analysis of Ambient Air Using Supercritical Fluid Desorption/Gas Chromatography

Abstract The work described in this paper shows how we have investigated the utility of polar polyimide sorbents for the collection of polar and non-polar volatile organic compounds in ambient air. The results indicate that supercritical carbon dioxide can be used to recover a variety of compounds with a wide range of volatilities from polyimide sorbents and that these compounds can be effectively collected onto an adsorbent micro-trap after the expansion of the fluid prior to thermal desorption gas chromatographic analysis. Molecular sieve 3A was used and found to have a very high capacity for removal of water from the supercritical fluid extract stream. The sieve tended to adsorb polar compounds in the absence of water; the presence of water sometimes reduced analyte adsorption. The method was used to collect, recover, and analyze volatile organic compounds from the air of a laboratory building and was shown to be quite sensitive for appropriate compounds.

Atmospheric sampling glow discharge ionization source for the determination of trace organic compounds in ambient air

A new atmospheric sampling ion source, based on the establishment of a glow discharge in ambient air drawn into a region of reduced pressure, is described. The source is simple, rugged, and relatively maintenance-free, exhibits a very short memory, and is extremely sensitive for compounds with high proton affinities, high electron affinities, high gas-phase acidities, and/or low ionization potentials. The effects of discharge voltage and ion source pressure on the nature of the mass spectra observed are described. These operating parameters affect the absolute number of ions observed and, particularly for positive ions, affect the distribution of the reagent ions and the degree of fragmentation. For illustrative purposes, the limit of detection of dynamic range of the ion source coupled with a mass spectrometer are discussed for 2,4,6-trinitrotoluene. For the present system, a detection limit of 1-2 parts per trillion and a linear dynamic range of at least 6 orders of magnitude are observed.

Development and evaluation of a novel gas and particle sampler for semivolatile chlorinated organic compounds in ambient air

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDevelopment and evaluation of a novel gas and particle sampler for semivolatile chlorinated organic compounds in ambient airDouglas A. Lane, N. Douglas. Johnson, Sydney C. Barton, Gordon H. S. Thomas, and William H. SchroederCite this: Environ. Sci. Technol. 1988, 22, 8, 941–947Publication Date (Print):August 1, 1988Publication History Published online1 May 2002Published inissue 1 August 1988https://doi.org/10.1021/es00173a012RIGHTS & PERMISSIONSArticle Views105Altmetric-Citations45LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (953 KB) Get e-Alerts Get e-Alerts

Sequential automated-analysis system for lower oxygenated organic-compounds in ambient air

Sequential automated-analysis system for lower oxygenated organic-compounds in ambient air

Application of pattern recognition to mass spectral data of toxic organic compounds in ambient air

The low resolution mass spectra of a set of 78 toxic, volatile organic compounds, the presence of which is routinely monitored in ambient air samples, were examined for information concerning chemical classes and compound identification. The mass spectra were converted to their autocorrelation spectra, and the transformed spectra were studied using pattern recognition techniques. The inherent structure of the data showed three major classes: nonhaloaromatics, chlorocarbons, and bromo- and bromochlorocarbons. Principal components models, with dimensionality obtained with a cross-validation technique, contained two or three dimensions. Classification accuracy for the training set compounds was high. A hierarchical classification scheme, using statistical pattern recognition and k-nearest neighbor methods, was developed for chemical class assignment and for compound identification from mass spectral data files. The method was applied to gas chromatography—mass spectral data of known compounds of calibration sets obtained on the air quality monitoring mass spectrometer. Classification accuracy as to chemical class was 87% and compound identification accuracy was 84% for the calibration data. A classification scheme, which could be the basis for a microcomputer based expert system for mass spectral interpretation, is described.

Classification and identification of hazardous organic compounds in ambient air by pattern recognition of mass spectral data

A new method for classification and identification of target air pollutants based on class modeling pattern recognition of autocorrelation transformed mass spectra has been developed. Target and other compounds can be classified into three classes: chloro compounds, bromoalkanes and bromoalkenes, and non-halobenzenes. After classification, the 78 target compounds are identified by comparing their mass spectra with those of their three nearest neighbors in the target set. This pattern recognition scheme has been applied to gas chromatography-mass spectrometry data from three field samples obtained in routine ambient air monitoring. The accuracy of target compound classification and identification was 88 and 85%. Seventy-five other compounds were tentatively identified in these samples by library search methods. Classification results showed good agreement between pattern recognition and library search techniques for the limited number of chloro and non-halobenzene compounds in the samples. However, a large number of hydrocarbons were misclassified as chloro compounds.

Sample integrity of trace level volatile organic compounds in ambient air stored in SUMMA® polished canisters

Sets of new and used SUMMA® polished stainless steel canisters were tested for storage stability of volatile organic compounds (VOCs). Evacuated canisters were filled at a controlled rate with ambient air containing added concentrations of 15 VOCs (14 chlorinated, one brominated) at < 2 ppbv. Concentrations of VOCs in each canister were then periodically determined during 7-day or 30-day storage periods using simultaneous flame ionization and electron capture detection. No initial decreases in concentrations of target compounds were observed. Statistical analysis of data showed that the relative standard deviation of concentrations of most VOCs in each canister set was 10% or less during the storage periods. For the 7-day tests, the mean change in concentration per day was within ± 3.2 %. These canisters appear suitable as an alternative to other sampling techniques, at least for most of the compounds tested here.