Thermal aspects of a micro thermal conductivity detector for micro gas chromatography

International audienceWe report on a micro Thermal Conductivity Detector (µTCD) design, simulation, fabrication and experimental characterization. The considered detector has been fabricated and integrated in a full micro gas chromatography device. It has been experimentally tested for different carrier gases, air, nitrogen and ethanol with different concentrations of three pollutants, Toluene, Ethylbenzene, and Xylene for instance. The device reveals to be sensitive for concentrations as low as 500 ppm. We consider different operation modes under constant temperature and constant current. We also consider steady state and transient operation modes. We show that for the same device, sensitivity strongly depends on operation mode. In addition to sensitivity enhancement, the transient operation mode enables energy consumption reduction and fast responses with measurements as fast as 0.9 ms. Experimental results are in very good agreement with 3D numerical multi-physical simulations based on Finite Element Method