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Chemical Micro Preconcentrators Development for Micro Gas Chromatography Systems

Microelectromechanical systems (MEMS) technology allows the realization of mechanical parts, sensors, actuators and electronics on silicon substrate. An attractive utilization of MEMS is to develop micro instruments for chemical analysis. An example is gas chromatography (GC) which is widely used in food, environmental, pharmaceutical, petroleum/refining, forensic/security, and flavors and fragrances industries. A MEMS-based micro GC (µGC) provides capabilities for quantitative analysis of complex chemical mixtures in the field with very short analysis time and small amounts of consumables.

The aim of this research effort is to enhance the sensitivity and selectivity of µGC instruments by implementing chemical amplification method known as preconcentration. A micro preconcentrator (µPC) extracts the target analytes from the sample matrix, concentrates them, and injects them into the separation column for analysis.

This work resulted in the development of silicon-glass bonded chips consisting of 7 mm x 7 mm x 0.38 mm multiport cavity with thousands of embedded 3D microstructures (to achieve high surface-to-volume ratio) coated with polymeric thin film adsorbents. Deep reactive ion etching (DRIE) was the enabling technology for the realization of µPCs. Several coating methods, such as inkjet printing of polymers and polymer precipitation from solution have been utilized to coat complex geometrical structures. One major outcome was the development of cobweb adsorbent structure. Moreover, the porous polymeric adsorbent Tenax TA in the film form was characterized, for the first time, for μPC application and shown to have similar properties to that of the granular form.

Several μPC designs were experimentally evaluated for their performance in concentrating volatile organic compounds, including cancer biomarkers, Propofol (anesthetic agent), environmental pollutants, and chemical warfare simulants. The possibility of utilizing the μPCs in practical applications such breath analysis was also demonstrated. / Ph. D.

Identiferoai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/29305
Date29 November 2010
CreatorsAlfeeli, Bassam
ContributorsElectrical and Computer Engineering, Agah, Masoud, Taylor, Larry T., Hendricks, Robert W., Wang, Anbo, Meehan, Kathleen
PublisherVirginia Tech
Source SetsVirginia Tech Theses and Dissertation
Detected LanguageEnglish
TypeDissertation
Formatapplication/pdf
RightsIn Copyright, http://rightsstatements.org/vocab/InC/1.0/
RelationAlfeeli_B_D_2010.pdf

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