SUMMARY

Recent advances in Micro and Nano technology have given gas chromatography (GC) systems improved detection ability, power efficiency and mobility. As a result, GC sub-systems, the preconcentrator, separation column and detector(s) have all been made more effective. Continuous efforts have been made to miniaturize the various detection devices, while improving the limit of detection and the range of gas type that can be detected. The Thermal Conductive Detector (TCD) is a joule-heating based sensor that is a commonly used detector in GC systems. This research will highlight a new concept of TCD that has been proposed to enhance the limit of detection of the sensor. The sensor model was developed with COMSOL Multi-physics software, and Finite Element Analysis (FEA) was used to study the proposed structure. The enhancement of the TCD sensor has been achieved through the realization of a novel structural design; platinum balanced cantilever-based TCD. The sensor was realized by using a selection of compatible materials and micro-fabrication processes at the Institute of Electronics and Nanotechnology, IEN. The 3-omega is a high SNR resistance measurement technique which uses continuous current. The sensor was designed and fabricated to withstand the high thermal stresses caused by this technique. Sensor performance has been studied in a GC system, and was compared with a commercial Flame Ionization Detector (FID) sensor. To further improve the detection limit of the TCD and simplify the resistance measurement technique, a TCD structure with double layer platinum balanced will be proposed. The new sensor design performance will be studied for a combined DC and AC resistance measurement technique, providing the high signal to noise ratio. The final assessment would be to investigate sensor performance in a GC system.