Sampling of organic compounds in the presence of reactive inorganic gases with Tenax GC

Pellizzari, Edo D.; Demian, Barbu A.; Krost, K. J.

doi:10.1021/ac00268a046

Cited by 79 publications

(40 citation statements)

References 21 publications

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“…Problems recognized with Tenax GC when used for air sampling include a rather high background 14 and chemical decomposition in the presence of oxidants, such as O 3 and NO x , that can produce VOC artifacts. 15,16 Often, however, no O 3 artifacts are reported. 17 Subsequently, Tenax TA was developed for air sampling purposes, a material with lower background, and some localized negative charges.…”

Section: Polymer/tenax Adsorbentsmentioning

confidence: 99%

“…Artifact formation with Tenax has been studied or reported for exposures to O 3 , 16,[21][22][23][24] nitrogen dioxide (NO 2 ), 16,22,24 nitrogen oxide (NO), 16,24 sulfur dioxide, hydrogen peroxide, 24 OH radical, 24 limonene oxidation products (with O 3 and NO 2 ), 22,24 and halogens (Cl 2 and Br 2 ). 25 Table 2 summarizes the O 3 -Tenax artifacts identified in the literature.…”

Section: Polymer/tenax Adsorbentsmentioning

confidence: 99%

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Ozone Artifacts and Carbonyl Measurements Using Tenax GR, Tenax TA, Carbopack B, and Carbopack X Adsorbents

Lee

Batterman

Jia

et al. 2006

Journal of the Air & Waste Management Association

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Four popular thermally desorbable adsorbents used for air sampling (Tenax TA, Tenax GR, Carbopack B, and Carbopack X) are examined for the potential to form artifacts with ozone (O 3 ) at environmental concentrations. The performance of these adsorbents for the ketone and aldehyde species identified as O 3 -adsorbent artifacts was also characterized, including recovery, linearity, and method detection limits (MDLs). Using gas chromatography/mass spectrometry, 13 different artifacts were identified and confirmed for both Tenax TA and Tenax GR, 9 for Carbopack B, but none for Carbopack X. Several O 3 artifacts not reported previously were identified, including: pentanal, 3-hexanone, 2-hexanone, hexanal, 3-heptanone, and heptanal with Tenax TA; pentanal, 3-hexanone, 2-hexanone, hexanal, and 3-heptanone on Tenax GR; and 1-octene and 1-nonene with Carbopack B. Levels of straight-chain aldehyde artifacts rapidly diminished after a few cycles of adsorbent conditioning/O 3 exposure, and concentrations could be predicted using a first-order model. Phenyl-substituted carbonyl artifacts (benzaldehyde and acetophenone) persisted on Tenax TA and GR even after 10 O 3 exposure-conditioning cycles. O 3 breakthrough through the adsorbent bed was most rapid in adsorbents that yielded the highest levels of artifacts. Overall, artifact composition and concentration are shown to depend on O 3 concentration and dose, conditioning method, and adsorbent type and age. Calibrations showed good linearity, and most compounds had reasonable recoveries, for example, 90 Ϯ 15% for Tenax TA, 97 Ϯ 23% for Tenax GR, 101 Ϯ 24% for Carbopack B, and 79 Ϯ 25% (91 Ϯ 9% for n-aldehydes) for Carbopack X. Benzeneacetaldehyde recovery was notably poorer (22-63% across the four adsorbents). MDLs for several compounds were relatively high, up to 5 ng. By accounting for both artifact formation and method performance, this work helps to identify which carbonyl compounds can be measured using thermally desorbable adsorbents and which may be prone to bias because of the formation of O 3 -adsorbent artifacts.

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Section: Polymer/tenax Adsorbentsmentioning

confidence: 99%

Section: Polymer/tenax Adsorbentsmentioning

confidence: 99%

Ozone Artifacts and Carbonyl Measurements Using Tenax GR, Tenax TA, Carbopack B, and Carbopack X Adsorbents

Lee

Batterman

Jia

et al. 2006

Journal of the Air & Waste Management Association

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“…20,21 Factors that may affect the volume of saturation considerably are temperature, sampling flow, relative humidity of the air, the concentration of pollutants, the physicochemical properties of the adsorbent and analyte, and the presence of other components in the mixture. 22,23 …”

Section: Comparison Between the Direct Sampling And Preconcentrationmentioning

confidence: 99%

Online Hourly Determination of 62 VOCs in Ambient Air: System Evaluation and Comparison with Another Two Analytical Techniques

Durana

Navazo

Alonso

et al. 2002

Journal of the Air & Waste Management Association

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This paper presents results of the processing and validation of data collected by an automatic gas chromatograph (AGC). This system was used to monitor 62 volatile organic compounds (VOCs) in urban air in the Basque Country, Spain. The nonpolar compounds (C 2 -C 10 ) identified-paraffins, olefins, aromatics, and chlorinated compounds-accounted for 88% of the mass of total nonmethane hydrocarbons (TNMHCs) in ambient air. The evaluation of linearity, precision, detection limits (DLs), and stability of retention times (RTs) indicates that the equipment is suitable for measuring ambient air automatically for prolonged periods (6 months). The calibration of the equipment using response factors calculated on the basis of the effective carbon number (ECN) showed variations of over 10% for acetylene, isoprene, and n-hexane. The results provided by the automatic chromatograph correlated significantly with simultaneous results from other widely used techniques for determining VOCs in ambient air: (1) portable GC, equipped with photoionization detector (PID), and (2) active adsorption on Tenax-TA followed by thermal desorption and chromatographic analysis.

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“…The use of combinations of different adsorbents in series can Increase the range of organic volatiles which might be determined by adsorptIOn-thermal desorption techniques [SS], but the problem of artefact formation increases with the number of different adsorbents used. The main problem which limits the applicability of adsorptive sampling is the formation of artefacts and losses by various mechanisms [41,[56][57][58][59][60][61][62][63][64][65][66]. Apart from the formation of artefacts during sample desorption by thermal decay of the sorbent, the main source of sample degradation are the reaction of reactive adsorbed compounds with each other, eIther during sampling or during storage, the reactIOn of adsorbed organic compounds with reactive trace species in the gas phase, e.g., ozone or nitrogen dioxide, and the thermal decay of sampled compounds during desorption.…”

Section: Thermal Desorptlonmentioning

confidence: 99%

“…Another possibhty is the formation of artefacts from the reaction of oxidizing atmospheric trace constituents such as ozone, hydrogen perOXIde, nitric acid or nitrogen dioxide with the adsorbent. As all these possible sources of sample degradatIOn depend strongly on the type of adsorbent, its preconditioning, the sampling condItions (temperature, sample volume, loading of adsorbent with sample) and the composition of the atmosphere, e.g., ozone concentration [56][57][58], it is difficult to generalize the limitations caused by these problems. Nevertheless, it is possible to establish a few rough guidelines.…”

Section: Thermal Desorptlonmentioning

confidence: 99%

Sampling of organic volatiles in the atmosphere at moderate and low pollution levels

Rudolph¹,

Müller²,

Koppmann³

1990

Analytica Chimica Acta

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Several techntques are avatlable for measunng organic volattles m the atmosphere. For measurements at low and moderate pollUtlon levels (between several p.g m-3 and a fraction of a p.g m-3 ), the eXIstmg methods can be adopted to a broad range of different compounds. Whole-atr samphng m stamless-steel containers With metal bellows valves combmed With subsequent gas chromatograpluc separatIOn after preconcentratlon 10 the laboratory IS probably the best procedure for low and medium molecular Weight trace gases of moderate or low polanty and reasonable cherrncal stability (e.g., hydrocarbons and halocarbons). For orgamc compounds of lower volatility, adsorptlve samphng on non-polar porous orgaruc polymers (e.g, Tenax) and thermal desorptlon combmed WIth cryotrappmg and gas chromatograpluc separation of the sampled compounds IS Widely used However, there are often substantial problems due to artefact formatIOn or loss reactIOns Owmg to the generally larger sample volumes, these problems are even more pronounced for sorptlve samphng techntques combmed with sample recovery by solvent extraction. Unfortunately, the general understandmg of the vanous processes of sample degradatlon due to cherrncal reactlons of reactlve components of the atmosphere With each other or WIth the sorbent IS not yet suffiCient to allow reasonable estlmates of the extent of such mterferences Without elaborate test procedures. Keywords. Au, Samplmg procedures; Extractlon, Orgamc volatdesThe demand for accurate, reliable and sensitive techniques for the monitoring of organic trace constituents in the atmosphere has increased tremendously in the recent past. The reasons include not only a growing concern for the quality of the environment but also the realization that atmosphenc pollution is not only a local problem. At the same time, the number of different organic compounds which are emitted into the atmosphere has been rising steadily. Further, it has been recognized that several substances which had been considered harmless can pose serious hazards to the enVIronment. There is a broad range of techniques for the determination of organic compounds at trace levels wmch are sufficiently sensitive and selective. Chromatography (predominantly LC and GC) is the most widely used method and allows the identification and quantification of organic compounds in sub-nanogram amounts. With few exceptions, the analysis itself is carried out in the laboratory, which means that the sample has somehow to be transported to the laboratory. For many kinds of environmental measurements, representative and contamination-or lossfree sampling often requires substantial efforts and iD general air is one of the most difficult environmenal media for sampling. The problems are easy to understand but difficult to solve. Sample contamers for air are not only more complicated than those for solid or liquid material but also, owing to the low density of air, the volume which has to be collected for an analysis for trace components is generally larger than that for...

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Sampling of organic compounds in the presence of reactive inorganic gases with Tenax GC

Cited by 79 publications

References 21 publications

Ozone Artifacts and Carbonyl Measurements Using Tenax GR, Tenax TA, Carbopack B, and Carbopack X Adsorbents

Ozone Artifacts and Carbonyl Measurements Using Tenax GR, Tenax TA, Carbopack B, and Carbopack X Adsorbents

Online Hourly Determination of 62 VOCs in Ambient Air: System Evaluation and Comparison with Another Two Analytical Techniques

Sampling of organic volatiles in the atmosphere at moderate and low pollution levels

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