Dissertation Defense

Progressive Cellular Architecture in Microscale Gas Chromatographs for Broad Chemical Analyses

Weilin Liao

Passcode: 191184

The detection and identification of volatile organic compounds (VOCs) is necessary for environmental monitoring applications such as for homeland security, industrial regulation, chemical process monitoring, healthcare, and more. A microscale gas chromatograph (μGC) is an instrument that separates, detects, identifies, and quantifies VOCs of interest by the characteristic individual retention time within a separation column and by the nature of the detector response.

This work investigates a μGC architecture that provides partial separation of the analytes into groups during sampling, and subsequently provides refined separation of each group using a cell tailored for that group. This architecture allows broad chemical analyses in an energy efficient manner and is amenable to monolithic integration on a microchip. Its final implementation incorporates three cells, each with a customized preconcentrator, separation column, and three detectors with distinct detection methods. All the essential microfluidic components are monolithically integrated within a single chip of 40.3×55.7 cm2.  The overall brassboard system is designed for performance, power efficiency, reliability, repeatability, and manufacturability. It has shown successful detection of a wide variety of polar and non-polar analytes over 58-170 Da with 86% correct identification rate in complex backgrounds.

Co-Chairs: Professor’s Yogesh B. Gianchandani & Dr. Yutao