Microfabricated chemical preconcentrators for gas-phase microanalytical detection systems

Voiculescu, Ioana; Zaghloul, Mona; Narasimhan, Nachchinarkkinian

doi:10.1016/j.trac.2008.01.016

Cited by 70 publications

(64 citation statements)

References 27 publications

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“…Nonetheless, Sandia Lab. (11,12) , among several others, proposed a layout that suspended the adsorbent inside the device (13) , or even the column (14) , which is a good approximation of three-dimensional devices.…”

Section: Introductionmentioning

confidence: 99%

The Use of Microchannels for Separation and Preconcentration: Comparison Between Three-Dimensional and Planar Configurations

Lima¹,

Silva

Simões

et al. 2014

RBAV

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Simulation and experimental measurements were used aiming at better understanding flow behavior in planar and three-dimensional microchannels used for separation or preconcentration. Two different microchannels configurations were designed, manufactured in acrylic and the surface was modified to adsorb volatile organic compounds (VOCs). Both channels configuration are 73 cm long, 100 µm wide and 40 µm deep. Simulation was carried out in COMSOL (FEMLAB) 3.2 ® and COSMOS flow 5.0 ® programs, tracer visualization and quartz crystal microbalance data were evaluated according to chromatographic concepts. Due to the higher axial velocity, planar microchannels are more adequate for preconcentration whereas three-dimensional ones show a good performance in the separation process.Keywords: Microchannels; Planar, Three-dimensional, Preconcentration. Resumo Foram usadas simulações computacionais e medidas experimentais com o objetivo de compreender o comportamento de fluidos em microcanais tridimensionais e planares que foram testados na função de separação ou pré-concentração. Duas configurações diferentes foram projetadas, construídas em acrílico e tiveram sua superfície modificada para adsorver compostos orgânicos voláteis (COVs

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Section: Introductionmentioning

confidence: 99%

The Use of Microchannels for Separation and Preconcentration: Comparison Between Three-Dimensional and Planar Configurations

Lima¹,

Silva

Simões

et al. 2014

RBAV

View full text Add to dashboard Cite

show abstract

“… metal fibres covered with an adsorbing material [6],  cylindrical tube coated with thin layer of a resistively heated material [6],  micro-electro-mechanical structures (MEMS) [7],  perforated polyimide hotplates [8][9][10][11][12],  3D planar concentrator [13,14],  chemical devices [15].…”

Section: Introductionmentioning

confidence: 99%

Explosives Vapors–Concentrating and Optoelectronic Detection

Wojtas¹,

Rutecka²,

Popiel³

et al. 2014

Metrology and Measurement Systems

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Detection of explosives vapors is an extremely difficult task. The sensitivity of currently constructed detectors is often insufficient. The paper presents a description of an explosive vapors concentrator that improves the detection limit of some explosives detectors. These detectors have been developed at the Institute of Optoelectronics. The concentrator is especially dedicated to operate with nitrogen oxide detectors. Preliminary measurements show that using the concentrator, the recorded amount of nitrogen dioxide released from a 0.5 ng sample of TNT increases by a factor of approx. 20. In the concentrator an induction heater is applied. Thanks to this and because of the miniaturization of the container with an adsorbing material (approx. 1 cm 3 ), an extremely high rate of temperature growth is achieved (up to 500 °C within approx. 25 s). The concentration process is controlled by a microcontroller. Compact construction and battery power supply provide a possibility of using the concentrator as a portable device.

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“…To improve the detection limit of sensor systems, a preconcentrator is incorporated into the analytical system to enhance the overall performance of the detector by preconcentrating the analyte using adsorbents. (1)(2)(3) Over the past several years, compounds in the material class of zeolites have been receiving increasing attention as sensitive adsorbents for gas detection. (4)(5)(6)(7) Zeolites are of interest because of their generally high adsorptivities and large surface areas.…”

Section: Introductionmentioning

confidence: 99%

Adsorption and Desorption Characteristics of Nanozeolites as Adsorbent for Dimethyl Methylphosphonate

2011

Sensors and Materials

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The selective adsorption of dimethyl methylphosphonate (DMMP) onto zeolites is described in this paper. Three types of zeolite, silicalite-1, ZSM (Zeolite Socony Mobil)-5, and Cu-ZSM-5, were synthesized and assembled onto the surface of a quartz crystal microbalance (QCM) covered with a Au film. The QCM was adopted as an effective tool to analyze the adsorption and desorption characteristics. The optimum desorption conditions were determined experimentally as a desorption temperature of 523 K and a desorption time of 30 min. Good repeatability could be obtained under these optimal desorption conditions. Adsorption capacity was determined by comparing the different zeolites as selective adsorbents for DMMP. Cu-ZSM-5 had the highest adsorption capacity and the best selectivity for the three zeolites. The effect of copper ions on the adsorption of DMMP was tested by synthesizing five Cu-ZSM-5 zeolites with different copper ion contents. Adsorption sensitivity increased in proportion to copper content before saturation. The sensitivity and detection limit of a QCM coated with Cu-ZSM-5 reached about 8.8 Hz/ppm and 0.3 ppm, respectively, confirming that Cu-ZSM-5 zeolite is a promising adsorbent for DMMP detection.

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Microfabricated chemical preconcentrators for gas-phase microanalytical detection systems

Cited by 70 publications

References 27 publications

The Use of Microchannels for Separation and Preconcentration: Comparison Between Three-Dimensional and Planar Configurations

The Use of Microchannels for Separation and Preconcentration: Comparison Between Three-Dimensional and Planar Configurations

Explosives Vapors–Concentrating and Optoelectronic Detection

Adsorption and Desorption Characteristics of Nanozeolites as Adsorbent for Dimethyl Methylphosphonate

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