為了監測工業區的空氣品質，使用多床吸附管搭配常見的主動採樣方法，並透過熱脫附串聯氣相層析質譜儀 (TD-GC/MS) 進行分析。本研究目的是為實驗室所設計的熱脫附系統建立一套採集周界空氣中最大量揮發性有機化合物的方法，並達到GC/MS高品質分析性能。將填有Carbotrap, Carboxen 1000和Carboxen 1003的不鏽鋼管成功應用於小體積採樣來檢測污染物，於2019年11月5日至20日在桃園觀音工業園區附近進行採樣，並在16天中進行每日24小時線上監測，數據顯示在半夜時揮發性有機化合物具有較高的濃度。使用既定方法來鑑定各種化合物和準確地定量，化合物中包含了有害空氣污染物 (HAPs) 。本方法準確、靈敏、簡單且非常適合用於確定VOCs的來源與分佈。TD-GC / MS系統於最佳化條件下，回收率介於84.14%-105.62%之間，方法偵測限介於0.09-0.86 ppb之間，相對標準偏差 (RSD) 小於17.7%。此外，還開發了一種新技術，在污染事件發生時能觸發採樣設備，可以在長期線上監測中支持及驗證TD-GC/MS的結果。;In order to observe trace-level volatile organic pollutants in the air of an industrial zone, a widely used active sampling methodology based on multi-sorbent bed tubes and analysis by thermal desorption (TD) coupled with gas chromatography mass spectrometry (GC/MS) was used. This study investigated the use of a lab-designed TD method to analyze the maximum possible number of VOCs in ambient air and achieve high-quality measurements with the TD-GC/MS technique. Stainless steel (s.s.) tubes filled with Carbotrap, Carboxen 1000 and Carboxen 1003 were applied successfully for low-volume sampling (0.03-1 L) to detect target VOCs at trace levels. Continuous on-line monitoring using TD-GC/MS was undertaken over a period of 16 days from November 5th to 20th, 2019 within the Guanyin industrial complex. The hourly data showed higher concentrations of volatile organic compounds (VOCs) in midnight. A wide variety of compounds including the ones classified as the hazardous air pollutants (HAPs) were identified and accurately quantified with the established method. The method is accurate, sensitive, simple and well-suited for determining VOC distributions from various sources in an industrial zone. Optimal running conditions for the TD-GC/MS system were developed in the laboratory yielding recoveries in the range of 84.14%-105.62%, method detection limits between 0.09 and 0.86 ppb and relative standard deviation (RSD) < 17.7%. During the on-line monitoring mode, the ion source was found to be rapidly contaminated by air matrix. Frequent cleaning of the ion source was necessary to maintain the required sensitivity of MS detection. As a result, an innovative technique of trigger-measurement was also subsequently developed by connecting an analyzer of total non-methane hydrocarbons (THC) to trigger TD-GC/MS measurements only when the THC levels surpass a threshold value of THC for which the air is deemed polluted. Since only polluted air is measured by TD-GC/MS, the ware-and-tare of the ion source in MS can be greatly reduced to prolong the service time of the ion source.
