Micro gas analyzers for environmental and medical applications

This paper presents the optimization of a micro gas preconcentrator based on a micro-channel in porous and non-porous silicon filled with an adequate adsorbent. This micro gas preconcentrator is both applicable in the fields of atmospheric pollution monitoring (Volatil Organic Compounds-VOCs) and explosives detection (nitroaromatic compounds). Different designs of micro-devices and adsorbent materials have been investigated since these two parameters are of importance in the performances of the microdevice. The optimization of the device and its operation were driven by its future application in outdoor environments. Parameters such as the preconcentration factor, cycle time and the influence of the humidity were considered along the optimization process. As a result of this study, a preconcentrator with a total cycle time of 10 minutes and the use of single wall carbon nanotubes (SWCNTs) as adsorbent exhibits a good preconcentration factor for VOCs with a limited influence of the humidity. The benefits of using porous silicon 1 24 25 26 27 28 to modify the gas desorption kinetics are also investigated.

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“…31 [6,7,8,9,10] , ion mobility spectrometry (IMS) and electronic nose (E-nose) . [11,12,13] [ 14,15,16,17] 32…”

Section: Introductionmentioning

confidence: 99%

A micro gas preconcentrator with improved performance for pollution monitoring and explosives detection

Camara

Breuil

Briand

et al. 2011

Analytica Chimica Acta

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“…2 Reducing power consumption and detector dead volume were equally important goals of our handheld micro-PDHID prototype for field testing. Consequently, the present work was focused upon understanding the impact of miniaturization upon detector performance and to use modeling in order to optimize gas flow rates, voltage biases and the GC outlet position for maximum sensitivity.…”

Section: Resultsmentioning

confidence: 99%

“…1 For field applications involving VOC detection, miniaturization of gas chromatography (GC) systems is essential. 2 Miniaturization of GC instruments includes decreasing the footprint of the overall package in order to improve size, weight, and power/portability (SWAPP) factors. We have extensively described the fabrication of a variety of monolithically-integrated micro-GC instrumentation previously, including valves, pumps, heaters, GC columns, sensors, and sample pre-concentrators, [3][4][5][6][7][8][9] for the detection of a broad range of chemical and biological VOCs.…”

Section: Introductionmentioning

confidence: 99%

Development of a Mesoscale Pulsed Discharge Helium Ionization Detector for Portable Gas Chromatography

et al. 2015

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Miniaturization of gas chromatography (GC) instrumentation enables field detection of volatile organic compounds (VOCs) for chembio-applications such as clandestine human transport and disease diagnostics. We fabricated a mesoscale pulsed discharge helium ionization detector (micro-PDHID) for integrating with our previously described mini-GC hardware. Stainless steel electrodes fabricated by photochemical etching and electroforming facilitated rapid prototyping and enabled nesting of inter-electrode insulators for self-alignment of the detector core during assembly. The prototype was ~10 cm 3 relative to >400 cm 3 of a commercial PDHID, but with a comparable time to sweep a VOC peak from the detector cell (170 ms and 127 ms, respectively). Electron trajectory modeling, gas flow rate, voltage bias, and GC outlet location were optimized for improving sensitivity. Despite 40-fold miniaturization, the micro-PDHID detected 18 ng of the human emanation, 3-methyl-2-hexenoic acid with <3-fold decrease in sensitivity relative to the commercial detector. The micro-PDHID was rugged and operated for 9 months without failure.

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“…Gas sensors are increasingly used in the growing markets of automotive industry and environmental monitoring [1]. The most common gas sensors are based on chemical interaction [2].…”

Section: Introductionmentioning

confidence: 99%

Flow compensation in a MEMS dual-thermal conductivity detector for hydrogen sensing in natural gas

Graaf

Prouza

Wolffenbuttel

2015

2015 Transducers - 2015 18th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS)

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Conventional thermal conductivity detectors (TCDs) demonstrate a flow dependence. The approach presented here to reduce the flow dependence is based on the on-line flow compensation using two thin-film sensors on membranes in parallel on the same chip that are differentially operated. These are laterally identically, but with a different depth of the detection chamber, resulting in different quasi-static sensitivities to the thermal conductivity of the sample gas. The effects of conduction and convection in the structure have been studied using COMSOL Multiphysics. First prototypes have been fabricated and are presently tested.

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Micro gas analyzers for environmental and medical applications

Cited by 101 publications

References 142 publications

A micro gas preconcentrator with improved performance for pollution monitoring and explosives detection

A micro gas preconcentrator with improved performance for pollution monitoring and explosives detection

Development of a Mesoscale Pulsed Discharge Helium Ionization Detector for Portable Gas Chromatography

Flow compensation in a MEMS dual-thermal conductivity detector for hydrogen sensing in natural gas

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