環境中揮發性有機物質監測儀器

The Environmental Monitoring Instrument of VOCs

王介亨(Chieh-Heng Wang) ； 王家麟(Jia-Lin Wang)

《科儀新知》 145期 (2005/04) Pp. 24-37

https://doi.org/10.29662/IT.200504.0002

摘要

揮發性有機物質為臭氧生成之前驅物，其主要來源為機動車輛、石化工業、塗料、電子廠及民生工業溶劑使用與生物源排放，直接或間接對於人類健康有相當的影響，以往普遍使用不鏽鋼罐或採樣袋作為採樣與分析的方式，但仍存在價格昂貴與時間解析不夠的缺點，因此近年來陸續出現新的自動化監測儀器，以滿足若干研究空氣污染問題上的需求。本文將因此針對現今VOCs在量測時所使用的主流分析儀器各部分的原理進行介紹。

並列摘要

Volatile organic compounds (VOCs) are pervasively present in the air and affect air quality in two aspects. The sources of VOCs are numerous and can be categorized into biogenic or anthropogenic with the latter being dominant and also posing greater hazards in terms of direct toxicity. Because the abundance of individual VOC is often low with several pptv to several tens of ppbv being the common levels, measurement of each individual VOC species with optimal precision and accuracy demands sample treatment and separation prior to detection. Direct measurement with absorption spectrometry although is fast and can obtain average abundance over a long distance, the accuracy, precision, sensitivity and compound coverage are often inadequate. Recently, the environmental monitoring of VOCs has been more relying on gas chromatographic (GC) based techniques owing to its high sensitivity, species resolution and time resolution in the range of minutes to an hour. Both flask sampling (off-line technique) and continuous automated GC measurement (on-line technique) are the two basic operation modes that account for the majority of the VOC measurement applications. In particular the on-line GC for continuous monitoring ambient VOCs is emerging as the more effective solution than the off-line usage. In this review article the basic principles of VOC analysis is reviewed; and also the basic designs or configurations of on-line systems developed in our laboratory and also found in commercial instruments are illustrated and compared.