Prevention of water vapour adsorption by carbon molecular sieves in sampling humid gases

Gawryś, Małgorzata; Fastyn, Patrycja; Gawlowski, J.; Gierczak, Tomasz; Niedzielski, Jan

doi:10.1016/s0021-9673(01)01250-x

Cited by 47 publications

(29 citation statements)

References 10 publications

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“…Since commonly used techniques of water removal like drying agents and Nafion tubes result in substantial loss of low-molecular-mass polar compounds and since dry purge of water after sample adsorption causes depletion of highly volatile VOCs, we decided to avoid excessive adsorption of water by reduction of the sample's relative humidity by diluting the bacterial headspace with dry air (Fig. 1) as proposed by Gawryś et al (2001). The dilution ratio of 1 : 8 (5 ml sample min 21 : 35 ml air min 21 ) was found to be optimal, providing the highest sampling efficiency (higher ratios resulted in purging of already adsorbed VOCs, while lower ratios did not reduce the Fig.…”

Section: Methodsmentioning

confidence: 99%

Characterization of volatile metabolites taken up by or released from Streptococcus pneumoniae and Haemophilus influenzae by using GC-MS

et al. 2012

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Volatile organic compounds (VOCs) released from or taken up by Streptococcus pneumoniae and Haemophilus influenzae cultures were analysed by means of GC-MS after adsorption of headspace samples on multi-bed sorption tubes. Sampling was performed at different time points during cultivation of bacteria to follow the dynamics of VOC metabolism. VOCs were identified not only by spectral library match but also based on retention times of native standards. As many as 34 volatile metabolites were released from S. pneumoniae and 28 from H. influenzae, comprising alcohols, aldehydes, esters, hydrocarbons, ketones and sulfur-containing compounds. For both species, acetic acid, acetaldehyde, methyl methacrylate, 2,3-butanedione and methanethiol were found in strongly elevated concentrations and 1-butanol and butanal in moderately elevated concentrations. In addition, characteristic volatile biomarkers were detected for both bacterial species and exclusively for S. pneumoniae, also catabolism of aldehydes (3-methylbutanal and hexanal) was found. The results obtained provide important input into the knowledge about volatile bacterial biomarkers, which may become particularly important for detection of pathogens in upper airways by breath-gas analysis in the future.

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Section: Methodsmentioning

confidence: 99%

Characterization of volatile metabolites taken up by or released from Streptococcus pneumoniae and Haemophilus influenzae by using GC-MS

et al. 2012

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“…Experimentally, the adsorption capacities of chloroanilines on montmorillonite and kaolinite sieves depend on the hydrophilicity and lipophilicity of adsorbates; that is, the extent of adsorption on hydrophobic adsorbents increases with lipophilicity of adsorbates (Angioi, et al, 2005;Polati, et al, 2006). Additionally, the effects of moisture competition and high temperature desorption, which reduce the VOC adsorption capacities of adsorbents, have been extensively investigated (Keener and Zhou, 1990;Chou and Chiou, 1997;Lercher and Seshan, 1997;Yun, et al, 1998;Gawryś et al, 2001;Bilgiç and Aşkin, 2003;Manjare and Ghoshal, 2006). Generally, various solvents (such as ketones and alcohols) are gathered together in an internal circulation cabinet.…”

Section: Introductionmentioning

confidence: 99%

Competition among Mixed Adsorbates Affecting the Adsorption of Gaseous Methyl Ethyl Ketone by Hydrophobic Molecular Sieve

Cheng

Tsai

2007

Aerosol Air Qual. Res.

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Internal circulation cabinets, equipped with adsorbents for emitted volatile organic compounds (VOCs), are extensively used to store organic solvents in Taiwanese university and hospital laboratories.This work evaluates how ketone and isopropanol (IPA) respectively influence the methyl ethyl ketone (MEK) adsorption capacity of a hydrophobic molecular sieve (MS) with a high Si/Al ratio of 1000, and concentration (C, ppm) are closely fitted using a Langmuir isotherm. Lower VOC concentration ratios less than 0.17 for mixing acetone and IPA respectively with MEK rarely affect the MEK adsorption by HiSiv 1000. However, the effect of competitive adsorption, which evidently reduces the adsorption capacity of MEK, is related to the higher mixture concentration ratio (> 0.80) of IPA to MEK. The experimental results show that the hydrophobicity characteristics of MEK, acetone and IPA were responsible for variation in adsorption capacity of hydrophobic molecular sieve. Working parameters of adsorbent materials in the internal circulation cabinet have been also provided for preventing breakthrough of VOC adsorption by the molecular sieve.

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“…Also, the adsorbent must avoid irreproducible results as well as contamination. Detailed description of characteristics of adsorbents is given in Table I (Camel & Caude, 1995;Gawrys, Fastyn, Gawlowski, Gierczak, & Niedzielski, 2001;Harper, 2000;Matisová & Škrabáková, 1995;Zielinska & Faujita, 1994).…”

Section: Sorbent Samplingmentioning

confidence: 99%

Volatile Organic Compounds: Sampling Methods and Their Worldwide Profile in Ambient Air

Kumar

Víden

2006

Environ Monit Assess

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The atmosphere is a particularly difficult analytical system because of the very low levels of substances to be analysed, sharp variations in pollutant levels with time and location, differences in wind, temperature and humidity. This makes the selection of an efficient sampling technique for air analysis a key step to reliable results. Generally, methods for volatile organic compounds sampling include collection of the whole air or preconcentration of samples on adsorbents. All the methods vary from each other according to the sampling technique, type of sorbent, method of extraction and identification technique. In this review paper we discuss various important aspects for sampling of volatile organic compounds by the widely used and advanced sampling methods. Characteristics of various adsorbents used for VOCs sampling are also described. Furthermore, this paper makes an effort to comprehensively review the concentration levels of volatile organic compounds along with the methodology used for analysis, in major cities of the world.

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Prevention of water vapour adsorption by carbon molecular sieves in sampling humid gases

Cited by 47 publications

References 10 publications

Characterization of volatile metabolites taken up by or released from Streptococcus pneumoniae and Haemophilus influenzae by using GC-MS

Characterization of volatile metabolites taken up by or released from Streptococcus pneumoniae and Haemophilus influenzae by using GC-MS

Competition among Mixed Adsorbates Affecting the Adsorption of Gaseous Methyl Ethyl Ketone by Hydrophobic Molecular Sieve

Volatile Organic Compounds: Sampling Methods and Their Worldwide Profile in Ambient Air

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