Development of Highly Sensitive and Selective Optical and Electrical Sensors for Micro-Gas Chromatography.

[摘要] Gas chromatography (GC) is a powerful tool in the analysis of volatile organic compound (VOC) mixtures. It has found applications in healthcare, industrial safety, homeland security, and environmental studies. However to extend its use from lab based to in-situ based applications it is vital to miniaturize the systems to develop so called micro-gas chromatographs (micro-GC). There are a multitude of issues associated with developing µGC systems. Most of these issues arise from miniaturization of the various components used in GC systems. From a sensing point of view, many sensors that have been reported are too bulky or fragile for use in portable GC systems, show a lack of uniformity in their sensing responses, or have very long response times prohibiting their use in micro-GC. This dissertation presents the development of optical and electrical sensors aimed at alleviating some of these issues.The first optical sensor developed consists of a polymer sensing film coated on silicon substrate via a variety of methods including, spin coating, drop coating, and spray coating. Several issues with the Fabry-Perot (FP) are discussed and solved including non-uniformity of responses, reproducibility, dead volumes due to integration, and fabrication ofsensor arrays. The sensors showed excellent sensitivity, with detection limits as low as 0.7 pg. An array of these sensors was also demonstrated and showed promise for use in pattern analysis and analyte discrimination. The second optical sensor characterized, worked on the principle of localized surface plasmon resonance (LSPR). The sensor was shown be capable of differentiating between vapors without the need for an array, i.e. with the use of only a single sensor. However the low sensitivity is still a stumbling block for this type of sensor.The final sensor detailed within this dissertation is a high frequency graphene field effect transistor sensor (GrFET). The detailed testing results described herein indicate unprecedented sensitivity for a pristine graphene nanoelectronic sensor along with ideal response and desorption times which have not been shown in previous sensors using this material. The sensors were also tested for their response to a series of eluted analytes separated using standard GC techniques.

[发布机构] University of Michigan

[效力级别] Optical and Electrical Sensors

[关键词] Sensors for Gas Chromatography;Optical and Electrical Sensors;Biomedical Engineering;Electrical Engineering;Engineering;Electrical Engineering