Microfluidic RF Communication System for Data Retrieval 🔥
	Micro Gas Chromatography for On-Chip Sensing and Analysis  🔥
	Material Behavior and Thermal Management in Microscale Systems
	MEMS Micropumps for Cryogenic Heat Transport
	MicroEngine: Structures and Devices
	MicroEngine: Fabrication and Characterization

  Micro Gas Chromatography for On-Chip Sensing and Analysis

The objective of this research is to develop a highly sensitive, mechanically robust, and mass-producible gas micro-detector designed for integration into a portable micro-gas chromatographic system capable of competing with the performance of traditionally laboratory instrumentation. The approach involves optimizing the performance and sensitivity of the detector by modeling, analyzing, and experimentally validating various heat flux pathways from the detector's active element. In addition, the modeling and testing processes are conducted to ensure the detector's resilience to mechanical shock and its compatibility with a wide range of thermal and chemical operating environments.

In the pursuit of novel gas sensors and detection mechanisms, limited effort has been directed toward improving thermal conductivity detectors—one of the oldest gas sensor technologies. However, thermal conductivity detectors are particularly well-suited for miniaturization, as they are sensitive to the concentration of components in a mixture rather than the total sample mass—a limitation of flame ionization detectors and mass spectrometers. As a result, miniaturized gas chromatographic systems employing thermal conductivity detectors can maintain functional sensitivity while handling smaller sample volumes, with the added benefits of lower power consumption and improved mechanical robustness.

The development of a highly sensitive, yet simple and durable detector—integrated into a miniaturized system—positions gas chromatography to have a broader impact across various fields. These include point-of-care health diagnostics, homeland security, industrial process control, and geological exploration.

Representative Publications
(^#denotes graduate students/postdocs supervised by X. Zhang; *denotes corresponding author by X. Zhang)

	Temperature distribution on thermal conductivity detectors for flow rate insensitivity B.C. Kaanta#, A.J. Jonca#, H. Chen, and X. Zhang* Sensors and Actuators A: Physical, 2011, 167(2): 146-151
	Effect of forced convection on thermal distribution in micro thermal conductivity detectors B.C. Kaanta#, H. Chen, and X. Zhang* Journal of Micromechanics and Microengineering, 2011, 21(4): 045017
	Novel device for calibration-free flow rate measurements in micro gas chromatographic systems B.C. Kaanta#, H. Chen, and X. Zhang* Journal of Micromechanics and Microengineering, 2010, 20(9): 095034
	A monolithically fabricated gas chromatography separation column with an integrated high sensitivity thermal conductivity detector B.C. Kaanta#, H. Chen, and X. Zhang* Journal of Micromechanics and Microengineering, 2010, 20(5): 055016

Ph.D. Dissertation

MEMS thermal conductivity sensor with flow rate detection and invariance for gas chromatography systems Bradley Kaanta, Ph.D. Dissertation, Boston University. (Advisor: Xin Zhang; January 2011)

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