以二維氣相層析監測空氣中氟氯碳化物及氫氟氯碳化物; Monitoring CFC and HCFC using Oxygen-doping two dimensional gas chromatography

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题名:	以二維氣相層析監測空氣中氟氯碳化物及氫氟氯碳化物;Monitoring CFC and HCFC using Oxygen-doping two dimensional gas chromatography
作者:	劉文治;Wen-tzu Liu
贡献者:	化學研究所
关键词:	氟氯碳化物;氫氟氯碳化物;氣相層析儀;綴氧;高斯分佈;二維;Gaussian distributtion;CFCs;HCFCs;Oxygen doping;GC;two dimensional
日期:	2008-07-02
上传时间:	2009-09-22 10:18:19 (UTC+8)
出版者:	國立中央大學圖書館
摘要:	氟氯碳化物(chlorofluorocarbon ; CFC)，因長生命期及化性穩定，一旦排放後會穩定漂至平流層破壞臭氧。隨著蒙特婁協議禁用氟氯碳化物，其取代品-氫氟氯碳化物(hydrochlorofluorocarbon ; HCFC)和氫氟碳化物(hydrofluorocarbon ; HFC)的使用量與日俱增，雖不致破壞臭氧，卻是極強的溫室效應氣體，面對全球暖化劇變。人們開始注意此三類物種排放。本研究將對三類物種作量測方法開發和結合野外長期監測研究三類物種在台灣的排放情形，以化學吸附劑前濃縮系統搭配二維氣相層析技術作為監測氟氯碳化物的基本分析方法，但ECD對HCFC和HFC偵測感度不佳，我們使用綴氧法(Oxygen Doping)於ECD中，形成綴氧電子捕獲偵檢器(Doping ECD)，提高此兩類取代物的靈敏度，使用管柱為PoraPLOT-Q+ PLOT雙管柱。此法優點為易於定性和定量，且系統簡單低廉，適合至野外架設長期監測站。將開發完成的方法應用於野外長期監測，在雲林台西監測針對CFC、HCFC和HFC作為期一個月的長期監測，在中大氣象站無排放的CF2ClCFCl2和CCl4在此區測得些許人為排放，其中CCl4明顯受東北風影響甚鉅；同樣受東北風影響物種CH2Cl2，濃度高達8 ppb；其餘物種如CF2Cl2、CF2CBr和CHCl3也測得人為排放。將監測數據以高斯分佈概念研析鹵碳化物的排放情形，發現物種若無人為排放，則數據符合高斯分佈；若存在人為排放，則呈現非高斯分佈，且整體分佈明顯傾向正偏差。 The continual anthropogenic chlorofluorocarbons (CFCs) are known to destroy stratospheric ozone because of their long lifetimes and chemical stability. The advent of the Montreal Protocol caused total phase-out of CFCs in 1996. The consumption of the replacements, hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs), have been increasing rapidly. Although they have limitted or no ozone depleting potentials (ODPs), they are very potent green house gases. In this study, a gas chromatographic (GC) method was developed to simultaneously measure CFCs, HCFCs and HFCs in the atmosphere. The system involved an automated preconcentration unit using chemical adsorbents combined with two dimensional GC equipped with electronic captured detector (ECD) for measuring CFCs. For HCFCs and HFCs the oxygen-doping ECD method was employed to enhance the sensitivity. The system was tested on campus and at the Taishi EPA monitoring station. Limited emissions of CF2ClCFCl2 and CCl4 were found, which can serve as a useful quality assurance tool to validate measurements. Other more variable species, i.g., CF2Cl2, CF2ClBr and CHCl3, were detected revealing the existence of sources. For the doping system deployed in Taishi station, strong emissions of CH2Cl2 with concentration excess of 8 ppb relative to the baseline condition was found. The datasets were further examined by Gaussian distribution, which is a novel approach to reveal variability and sources of halocarbons.
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