Continuous monitoring of volatile organic compounds in air emissions using an on-line membrane extraction-microtrap-gas chromatographic system

Mitra, Somenath; Zhu, Naihong; Zhang, Xin; Kebbekus, Barbara B.

doi:10.1016/0021-9673(95)01374-1

Cited by 59 publications

(30 citation statements)

References 12 publications

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“…It provides better quality data at a lower cost, and eliminates errors introduced during sampling and laboratory handling [12,13]. On-line methods also provide real-time information that can be used for process control [12,14]. Consequently there is much interest in continuous monitoring of organics in drinking water, industrial wastewater, groundwater, and process water, and in safeguarding water reservoirs for homeland security.…”

Section: Introductionmentioning

confidence: 97%

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Development of continuous on-line purge and trap analysis

Saridara

Brukh

Mitra³

2006

J. Sep. Sci.

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An on-line purge and trap system for continuous monitoring of Volatile Organic Compounds (VOC) is presented. The purge chamber was designed for continuous extraction of VOC from water with nitrogen. The analytes were preconcentrated on a microtrap prior to analysis by GC with flame ionization detection. The microtrap served as a fast injection device for carrying out analysis at high frequency. Continuous monitoring was accomplished by performing injections at fixed intervals. This system showed high sensitivity, high precision, detection limits at the ppb level, and stable response over long periods of continuous operation. Factors affecting system performance were studied. A predictive model based on gas-liquid partitioning is also presented.

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Section: Introductionmentioning

confidence: 97%

“…The microtrap has been used as a stand-alone device, or in conjunction with a gas sampling valve [19,23,24]. Such devices show several advantages; for example, they are simple, can be operated automatically in on-line monitoring, yield low detection limits, and can handle relatively large concentrations of moisture [14,25].…”

Section: Introductionmentioning

confidence: 99%

Development of continuous on-line purge and trap analysis

Saridara

Brukh

Mitra³

2006

J. Sep. Sci.

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“…[6][7][8][9][10] A fused-silica column has a very low capacity for analytes and breakthrough time is very short. A long-capillary column is difficult to heat uniformly, which results in broad peaks.…”

Section: Resultsmentioning

confidence: 99%

Design of continuous‐monitoring device based on membrane extraction with sorbent interface and micro‐gas chromatograph

Ciucanu

Pawliszyn

2001

Field Analytical Chem & Tech

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A device for the continuous monitoring of the volatile and semivolatile organic compounds in air by membrane extraction followed by sorbent concentration and gas chromatographic separation is discussed. The device samples headspace and makes automatic injections followed by rapid separation and quantification. The main components of the system include membrane module, microtrap, and transfer line. A membrane module, microtrap, and fan are mounted in a housing, together constituting a MESI (membrane-extraction sorbent interface) sampling unit. A heated silicosteel capillary column was used as the transfer line, avoiding adsorption and condensation of analytes and performing separation of the analytes prior to detection. The device demonstrated potential for field monitoring of aromatic hydrocarbons, chlorinated compounds, and terpenoids.

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“…No caso de uma membrana microporosa a permeação ocorre por difusão direta dos analitos através dos poros da membrana 8 . Para membranas não porosas o mecanismo de transporte dos analitos da amostra para a membrana e desta para a corrente de gás inerte ocorre em três etapas: migração dos analitos da fase aquosa para a superfície da membrana, onde eles são dissolvidos; migração pela parede da membrana, sob gradiente de concentração; e dessorção na outra face da membrana, com dissolução no gás de transporte 8,13 . Pode-se demonstrar que, para membranas tubulares finas e amostras gasosas, a velocidade de transferência de massa, n, de uma determinada espécie é dada por 7 :…”

Section: Membranas E Processo De Permeaçãounclassified

Extração e pré-concentração de compostos orgânicos voláteis por permeação em membrana para análise cromatográfica

Carasek¹,

Valente²,

Augusto³

2000

Quím. Nova

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EXTRACTION AND PRE-CONCENTRATION OF VOLATILE ORGANIC COMPOUNDS BY MEMBRANE PERMEATION FOR CHROMATOGRAPHY ANALYSIS. This work discusses sample preparation processes for gas chromatography (GC) based on the technique of extraction through membrane permeation (MPE). The MPE technique may be easily coupled to GC via a relatively simple device, which is a module that holds the membrane and is directly connected to the GC column. The possibility of operational errors due to sample handling is substantially reduced in an MPE-GC system because the sample preparation and the chemical analysis are accomplished as a one-step process. The MPE technique is of relatively wide application as it can be used for aqueous samples, solid samples and gaseous samples. Depending on the type of sample the extraction is performed with the membrane in direct contact with the sample or in contact with its headspace. The MPE-GC technique is very useful in trace analysis, due to the timedependent enrichment of the analyte. A typical application of MPE-GC is the analysis of VOCs present in water that may be accomplished with detection limits at the low ppb (µgL -1 ) level.Keywords: membrane permeation; volatile organic compounds; gas chromatography. DIVULGAÇÃO INTRODUÇÃOA extração de analitos por permeação em membranas (EPM) como técnica de preparação de amostras para análise química foi primeiramente relatada na década de sessenta, para análises de ar e água por espectroscopia de massas (EM), utilizando-se membranas semipermeáveis planas 1 . Este relato motivou a continuidade de pesquisas com EPM, pela sua potencialidade como método de preparação de amostras seletivo, eficiente, livre de solventes, simples, rápido, de baixo custo e independente do tipo de instrumento utilizado. Ademais, com dispositivos adequados, a EPM permite, em uma única etapa, separar os componentes da matriz, concentrá-los e dirigí-los para o instrumento analítico, possibilitando determinações analíticas rápidas e monitoramento contínuo direto (on-line) 2 . A partir de 1974 3 as características de membranas tubulares vêm sendo exploradas, pois elas apresentam vantagens sobre as membranas planas para certas aplicações analíticas 4-6 . Apesar de três décadas de desenvolvimento de tecnologia de EPM existe pouca informação de seu uso em preparação de amostras para cromatografia gasosa (CG) 7 . Recentemente foi demonstrado que a combinação de EPM-CG é uma promissora tecnologia para a extração e análise de compostos orgânicos voláteis (COV) de água e ar 8 . No Brasil, diversos pesquisadores tem contribuído com estudos fundamentais e propostas de uso de separação por permeação em membranas para diversas aplicações. Pereira, Habert, Nóbrega e Borges 9 estudaram a separação de contaminantes voláteis em águas por pervaporação através de membranas poliméricas. Mendes, Pimpim, Kotiaho, Barone e Eberlin desenvolveram um módulo de permeação em membrana para introdução seletiva de analitos em espectrômetro de massas 10 ; uma modificação deste dispositivo foi empregada na determina...

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Continuous monitoring of volatile organic compounds in air emissions using an on-line membrane extraction-microtrap-gas chromatographic system

Cited by 59 publications

References 12 publications

Development of continuous on-line purge and trap analysis

Development of continuous on-line purge and trap analysis

Design of continuous‐monitoring device based on membrane extraction with sorbent interface and micro‐gas chromatograph

Extração e pré-concentração de compostos orgânicos voláteis por permeação em membrana para análise cromatográfica

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