微型氣相層析儀關鍵元件開發及可靠性系統整合應用於氣態有機化合物檢測

Abstract

基於文明進步和產業成熟發展，造成各種污染物的產生。揮發性有機化合物(VOCs)的污染已經成為環境和人類健康最嚴重的問題。因此，空氣品質監測需要客觀、標準、低成本和可攜式的氣體分析裝置。 於微型氣相層析儀關鍵元件的開發中，全氟磺酸薄膜除水器(Nafion® dehydrator)成功的被提出，並且與微型氣相層析系統整合，用於選擇性除去氣態有機化合物採樣氣流中的水氣。本研究證實其最大脫水效率可達55％，而且最小相對濕度(R.H.)可達到20％。應用於微型氣相層析系統，在於含有水氣的揮發性有機氣體混合物的採樣實驗中，顯示色譜峰值信號在經過除水處理後可以恢復。此成果證明了使用全氟磺酸薄膜除水器，可以成功的防止微型氣相層析儀在長期測量的過程中，因為高濕度環境所造成的信號失真。無電極鍍金技術(electroless gold plating)成功的在本論文中，證實能夠在微型前濃縮器(μPCT)和分離管柱晶片(μSC)流道內進行微型加熱器的製造，並且其快速的熱脫附和分離效率證實了此微型加熱器的加熱效率。此外，四乙氧基矽烷(TEOS)於本研究中首例被應用為靜相材料，並整合於無電極鍍金的分離管柱晶片。並且由於四乙氧基矽烷呈現親水性質，於本研究中成功的應用於高極性有機化合物的分離和分析。堆疊式的電極感測平台藉由標準的互補式金屬氧化物半導體微機電(CMOSMEMS)技術實現，其獨特的堆疊狀結構可以有效的增加感測器的面積。藉由使用奈米單層膜保護團簇(MPCs)感測材料可以證明此平台具備良好的線性度和靈敏度。此感測平台可以進一步與標準氣相層析系統整合，其能夠應用於感測經由分離管柱洗滌出的揮發性有機氣體，並且與標準之火焰離子燃燒感測器具備相同的分析結果。 在可靠性的微型氣相層析系統的整合中，本研究成功的提出一微型氣相層析系統，該系統與高流量前濃縮器、分離管柱模組、光離子化感測器模組、Arduino™開發平台、觸控螢幕元件以及無線模組整合。並且兩種使用者情境的物聯網解決方案被首次的整合於本微型氣相層析系統之中。三種標準配置的揮發性有機氣體(苯、甲苯和間二甲苯)被應用於驗證本系統的功能性。本研究首例應用微型氣相層析儀應用於氯胺酮熱裂解物標誌感測，並鑑定2-氯苯甲醛為其標記物。微型氣相層析系統對於2-氯苯甲醛呈現良好的再現性和線性度，證實本系統可應用於氯胺酮熱裂解物檢測。本系統針對2-氯苯甲醛標記物的最低量測極限為7.54 ppb。

With the increasing civilization and the evolution of technologies in different industry sectors, the generation of various pollutants has become an in-ignorable issue for the human beings. The volatile organic compounds (VOCs) pollutions has become one of the most serious problems for the environment and human health. Therefore, an objective, standard, cost effective, and near-real-time portable gas analysis device are necessary for air quality monitoring. In this dissertation, a micro gas chromatograph (μGC) including several key components are developed. A Nafion® dehydrator is successfully developed and integrated with the μGC to selectively remove the water vapor from the gaseous organic compounds sampling stream. The maximum dehydration efficiency of approximately 55% can be obtained and the minimum relative humidity (R.H.) of 20% can be achieved. For the μGC application of separating different compounds with water vapor, we successfully demonstrate that the peak signal of chromatogram can be rehabilitated after dehydration and the signal distortion can be prevented after long term measurement at high humidity environment. For the other key components, the electroless gold plating is successfully performed to fabricate the microheater inside the micromachined preconcentrator (μPCT) and the micromachined separation column (μSC). The rapid thermal desorption and efficiency of separation are demonstrated due to high heating efficiency. The novel tetraethoxysilane (TEOS) is firstly proposed to serve as the stationary phase integrated with the electroless gold plated μSC, and it is successfully demonstrated to separate and analyze the high polarity organic compounds due to the hydrophilic property of TEOS. As for the detection components, the reliable stacked electrode type gas sensor platforms are successfully demonstrated by using the standard CMOS-MEMS fabrication processes, and its unique structure can effectively increase the sensor sensitivity due to increased sensing area at a given volume. The great linearity and sensitivity of the CMOS-MEMS based sensor were demonstrated by employing monolayer-protected gold nanoclusters (MPCs) materials. The stacked electrode sensor platform with MPCs sensing material is successfully integrated with the standard GC system. The injected VOCs can be effectively sensed and the accurate retention times can be achieved compared to a standard flame ionization detector (FID). We have successfully demonstrated a μGC system including a high flow volume preconcentrator, a separation column module, a PID module, the Arduino™ platform, the touchscreen and wireless modules. The IoT (internet of things) solution with two user scenarios and the back-end peak detection algorithm are firstly developed and integrated with μGC system. The functionalities of the device architecture are verified in this study by three VOC vapors (benzene, toluene and m-xylene). This is the first study to apply the μGC to analyze the pyrolysis vapor products generated from ketamine, and 2-chlorobenzaldehyde is identified as the marker. The high reproducibility, good linearity and repeatable results are demonstrated using this μGC system and the limit of the detection (LOD) was approximately 7.54 ppb.