Development of Smartphone-Based Gas Sensor Using Plasma Emission Spectroscopy

• Main Authors: Po-Wei Yeh, 葉柏緯
• Other Authors: Cheng-Che Hsu
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/07011122671600422611

碩士 === 國立臺灣大學 === 化學工程學研究所 === 104 === A low-cost and flexible atmospheric-pressure microplasma generation device (MGD), which is used to detect gas, is presented. This MGD is made of double-side copper clad laminate (CCL) and dielectric fiberglass; the MGD electrode patterns are defined using the toner-transfer method and wet etching. Comparing to traditional manufacture of plasma device, this work demonstrates a less-cost, more customized method for electrode patterning and the capability of mass production. Furthermore, using this MGD with a specially-designed electrode arrangement (floating electrode), the optical intensity of plasma is enhanced. We also discuss the influence of different parameters of floating electrode on plasma properties. When plasma reacts with the analyte, the vapor is excited and emits light. Then, we obtain plasma optical emission from spectrometer. Each molecule emits the light with its specific wavelength; therefore, we can utilize this unique information to qualify and/or quantify contamination in the sample. There are two parts in this thesis. In the first part, we use optimal parameters of floationg electrode of MGD to analyze organic compounds by plasma emission spectroscopy in Argon. This system can identify organic compounds with CN (388 nm) bond and detect ethanol with detection limit at 25 ppm. A nearly linear calibration curve can be obtained for ethanol. The second part of this study is focused on developing a real portable gas sensor. We miniaturize the whole system, including the power supply, plasma device and spectrometer. Moreover, we use the smartphone as a platform for analysis. In this part, there is a discussion of matching between portable power supply and MGD. Finally, we identify normal gas and organic gas and the possibility of quantitative analysis.