Some critical parameters in collection, recovery and gas chromatographic analysis of organic pollutants in ambient air using light adsorbents

Bertoni, G.; Bruner, F.; Liberti, A.; Perrino, Cinzia

doi:10.1016/s0021-9673(00)80299-x

Cited by 91 publications

(26 citation statements)

References 15 publications

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“…Figure 1 shows the pattern ofdesorption recovery ofacetonitrile (y axis) when varying the amount loaded (x axis) and the air volume sampled (z axis). It should be noted that o f the amount trapped decreases exponentially when the amount loaded increases (at the same sampling volume) [30]. The same pattern can be observed in the desorption recoveries when the sampling volume increases (at the same loaded amount).…”

Section: Resultssupporting

confidence: 68%

“…The most volatile compounds are not completely retained by the first trap for the higher amounts and volumes o f air sampled, as discussed above. At the higher amounts, methanol is not retained even by the back-up trap because, as is known, its B T V strongly decreases when concentrations are increased [30]. The compounds retained best are not mentioned in Table III because they were not found in the back-up trap.…”

Section: Resultsmentioning

confidence: 96%

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Evaluation of a new dualsorbent trap for organic pollutants of different volatility

1999

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Section: Resultssupporting

confidence: 68%

Section: Resultsmentioning

confidence: 96%

Evaluation of a new dualsorbent trap for organic pollutants of different volatility

1999

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“…A back-up trap was employed in all the experiments to verify that all the compounds were completely retained by the main trap. The BTVs were strongly dependent on the concentration of the compounds examined and also on the concentrations of the other constituents of the mixture [40]. Therefore, values reported in the literature must be verified before application under real conditions.…”

Section: Resultsmentioning

confidence: 97%

Sampling and analysis of volatile organic compounds in air using a dualsorbent trap

2000

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“…In order to trap odorous compounds with very different properties, multi-bed sorbents seem to be useful [7] and therefore two sorbents: a carbon molecular sieve, Carboxen 564, and a porous polymer, Tenax TA were used alone or combined in this study. In a two-bed sorbent, Tenax TA is placed first to trap heavy molecules and Carboxen 564 is put secondly to trap smaller compounds.The influence of several factors such as temperature, concentration, flow rate and humidity should be considered on adsorption process [8]. In some cases, field sampling depends on weather conditions.…”

mentioning

confidence: 99%

“…The influence of several factors such as temperature, concentration, flow rate and humidity should be considered on adsorption process [8]. In some cases, field sampling depends on weather conditions.…”

mentioning

confidence: 99%

Advantages and limits of adsorption sampling for physico-chemical measurements of odorous compounds

Guillot¹,

Fernández²,

Cloirec³

2000

Analusis

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A lot of activities such as agricultural and industrial plants can be responsible of malodorous emissions that induce annoyance for human beings [1]. Odours, which are due to the presence in the air of organic and inorganic complex mixture at very low concentrations, are still not easy to analyse. Gas chromatography coupled with mass spectrometry (GC/MS) is generally used and seems to be the most powerful analytical technique available today to analyse organic odorous compounds. According to the very low perception levels, an adsorption step on a suitable solid sorbent is often required as sample preconcentration. Sample recovery is generally carried out by thermal desorption (TD) followed by analytes separation and detection using gas chromatography and mass spectrometry (GC/MS). This last technique is convenient for evaluating present organic molecules and their concentration [2]. For many applications, it has become the standard method for the determination of target compounds in atmosphere [3][4][5][6].Difficulties in the overall analysis of malodorous atmospheres arise from the different properties of their components, such as volatility, polarity and reactivity. None of commercial sorbents can be considered universal, i.e. available to retain quantitatively and later to release all volatile organic pollutants. So, the choice of a sorbent is very important to preserve sample integrity. In order to trap odorous compounds with very different properties, multi-bed sorbents seem to be useful [7] and therefore two sorbents: a carbon molecular sieve, Carboxen 564, and a porous polymer, Tenax TA were used alone or combined in this study. In a two-bed sorbent, Tenax TA is placed first to trap heavy molecules and Carboxen 564 is put secondly to trap smaller compounds.The influence of several factors such as temperature, concentration, flow rate and humidity should be considered on adsorption process [8]. In some cases, field sampling depends on weather conditions. For example, 90 % relative humidity (r.h.) at 25°C refers to a water vapour concentration of 21000 mg.m . Thus, when air is collected during rain or high atmospheric humidity, water may be the only major compound retained on sorbent material because of organic compound levels which are typically lower [9]. Presence of water in the collected sample is also unacceptable because it presents a major problem in the subsequent GC/MS analysis. There is a gradual desactivation of the chromatographic column after repeated analysis and injection of water can cause failure when using mass spectrometry. In humid conditions, Tenax TA and Carboxen 564 were studied. Several methods have also been developed to remove water vapour from the sample stream before reaching the sorbent tube, involving absorption with hygroscopic salts [10][11] or Nafion dryers [12], but water removal leads to losses of polar compounds. Another approach is to trap the water of the effluent by condensation at low temperatures [13]. However, their suitability for the whole set of compounds is stil...

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Some critical parameters in collection, recovery and gas chromatographic analysis of organic pollutants in ambient air using light adsorbents

Cited by 91 publications

References 15 publications

Evaluation of a new dualsorbent trap for organic pollutants of different volatility

Evaluation of a new dualsorbent trap for organic pollutants of different volatility

Sampling and analysis of volatile organic compounds in air using a dualsorbent trap

Advantages and limits of adsorption sampling for physico-chemical measurements of odorous compounds

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