Effects of flow rate and temperature on the thermal desorbability of polycyclic aromatic hydrocarbons and pesticides from Tenax-GC

Pankow, James F.; Kristensen, Toni J.; Isabelle, Lorne M.

doi:10.1021/ac00263a042

Cited by 36 publications

(24 citation statements)

References 15 publications

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“…With desorption then occurring in a backflush mode, maximum recoveries of all compounds would be obtained. The investigation of SRTD with cartridges of Tenax-TA alone allowed an examination of: 1) the suitability of Tenax-TA in SRTD with PCBs and PBBs; as well as 2) the inherent desorbabilities of PCBs and PBBs from that sorbent, as discussed elsewhere for pesticides and polycyclic aromatic hydrocarbons (PAHs) [32].…”

Section: Srtd Cartridgesmentioning

confidence: 99%

“…When ATD with these compounds is possible, or when SRTD with desorption flow through a portion of Tenax-TA is used, it will be of interest to know the optimal, congener-dependent temperatures and desorption carrier gas flow rates. This information may be obtained from the above data in a manner similar to that used by Pankow and Kristensen [32] for the thermal desorption of PAHs and pesticides from Tenax-GC.…”

Section: Retention Volume Vr and Sorbent Cartridge Theoretical Platesmentioning

confidence: 99%

“…When the desorption is occurring to a GC column, then during the desorption, V = Ve (TIT,) (Pe/P) where Ve, T, , and P, are the desorption carrier gas volume, temperature (Kelvin), and pressure (absolute) measured at the end of the cartridge, and T and P are the desorption temperature and pressure in the cartridge. By plotting the cumulative percentage recovered vs. V, estimates of N and VR can be obtained [32]. The steepness of the curve at V= VR provides a measure of N. When the compound is 50% recovered, V = VR.…”

Section: Retention Volume Vr and Sorbent Cartridge Theoretical Platesmentioning

confidence: 99%

“…For reasons explained elsewhere [32] Table 2 can be used to help in selecting the required conditions for desorbing PCBs and PBBs from a bed of Tenax-TA with a cross section and packing density (Le., HETP values for the various compounds) similar to that used in this study. Since VR/N"* equals the standard deviation (a) of a desorbing peak, for that peak, near quantitative desorption from asorbent bed will occurwhen V=VR + 2a = VR (1 + 2/N1/*) [38].…”

Section: Retention Volume Vr and Sorbent Cartridge Theoretical Platesmentioning

confidence: 99%

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Solvent removal/thermal desorption (SRTD) for extract concentration and capillary column injection

Hart¹,

Pankow²

1987

J. High Resol. Chromatogr.

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SummaryMany solvent extracts must be concentrated prior to analysis. Both Kuderna-Danish (K-D) concentration and inert gas blowdown are commonly used. Significant losses often occur with the latter. Solvent removaVthermal desorption (SRTD) on a precolumn was investigated here as an alternative or supplement to these methods. The compounds studied included polychlorinated biphenyls (PCBs) and polybrominated biphenyls (PBBs).SRTD wascarriedout by injecting 100pLofextractintoa cartridge-type precolumn, selectively volatilizing the solvent with a stream of carrier gas, then thermally desorbing the analytes to a fused silica capillary gas chromatography (GC) column. The mean total recoveries and mean standard errors obtained were 109 and t 12%, respectively. SRTD was found to give sharper peaks than were obtainable with on-column injection. Method detection limits accessible for PCBs by capillary GC with electron impact mass spectrometry with the assistance of SRTD were estimated. Overall, SRTD was found to be an effective, rapid, high recovery concentration method for solvent extracts.

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Section: Srtd Cartridgesmentioning

confidence: 99%

Section: Retention Volume Vr and Sorbent Cartridge Theoretical Platesmentioning

confidence: 99%

Section: Retention Volume Vr and Sorbent Cartridge Theoretical Platesmentioning

confidence: 99%

Section: Retention Volume Vr and Sorbent Cartridge Theoretical Platesmentioning

confidence: 99%

See 2 more Smart Citations

Solvent removal/thermal desorption (SRTD) for extract concentration and capillary column injection

Hart¹,

Pankow²

1987

J. High Resol. Chromatogr.

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“…The thermal stability of both the adsorbent and the adsorbate limit the maximum temperatures for the thermal desorption process and thus reduces the recovery efficiency for compounds of very low volatility [54]. 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.…”

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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Cold trapping of volatile organic compounds on fused silica capillary columns

Pankow

1983

J. High Resol. Chromatogr.

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SummaryA 30 m, 0.25 mm ID, fused silica capillary column at temperatures from -60 to -1 OOOC has been shown to be a quantitative trap for organic compounds with volatilities ranging from that of 1 ,I -dichloroethene to that of chlorobenzene.Thistypeof "whole column cryotrapping" provided sharp peaks (peak width approximately 4-7 seconds) for all compounds at a trapping temperature of -8OOC and with high carrier gas pressures and linear velocities (30 psi and 110 cm/s, respectively). Whole column cryotrapping possesses great simplicity, chromatographic efficiency (no trapping loop connections), and a built-in indicator of quality assurance for trapping efficiency (i.e., peak shape). These advantages are extremely attractive and are indicative of the fact that the potential of this approach has not yet been fully appreciated.

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Effects of flow rate and temperature on the thermal desorbability of polycyclic aromatic hydrocarbons and pesticides from Tenax-GC

Cited by 36 publications

References 15 publications

Solvent removal/thermal desorption (SRTD) for extract concentration and capillary column injection

Solvent removal/thermal desorption (SRTD) for extract concentration and capillary column injection

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

Cold trapping of volatile organic compounds on fused silica capillary columns

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