| 摘要: | 室內環境中低濃度揮發性有機物的暴露被懷疑與病態建築症候群(sick building syndrome)有關。本研究針對室內空氣污染的暴露評估，利用固相微萃取設備所製作的被動式採樣器，對低濃度之苯、甲苯、乙苯、及二甲苯蒸氣進行採集效能之測試。 本研究以Carboxen/Polydimethylsiloxane (CAR/PDMS)纖維為採樣器之主體，經組裝成被動式採樣器後，利用空氣採樣袋及動態標準氣體製造系統製備不同濃度之苯、甲苯、乙苯、及鄰二甲苯蒸氣，進行擴散式被動採樣及相關評估。樣本收集完畢後，直接插入氣相層析質譜儀之注射部進行樣本之脫附與分析，並以Selected Ion Recording(SIR)模式偵測。 本研究利用標準溶液建立檢量線所推算之方法偵測極限分別為: 0.21ng(苯)、0.026 ng(甲苯)、0.0028 ng(乙苯)及0.159ng(鄰二甲苯)。利用製備之已知濃度標準蒸氣評估，本研究所設計之被動式採樣器之實驗採樣率分別為苯: (7.46?0.63)?10-3 mL/min﹔甲苯: (6.61?0.87)?10-3 mL/min﹔乙苯: (7.22?0.71)?10-3 mL/min﹔及鄰二甲苯: (7.39?0.84)?10-3 mL/min。溫度(4℃~25℃)和風速(0~50fpm)不會四種物質的影響採樣率，但甲苯和鄰二甲苯之採樣則會受濕度影響。此外，短時間(如5min)、低濃度(如: 0.1 ppm)的暴露，四種物質皆可有效採集；4℃下儲存兩天，BTEX四種物質的樣本回收都可達100?20%。 本研究所設計之採樣分析方法結合被動式採樣與固相微萃取設備的優點，與現有方法比較，更具有方便、敏感的特色。對於未來室內低濃度揮發性有機物的偵測與相關的個人暴露評估，本研究所設計的採樣方法應是理想的工具。; Diffusive Sampling of Low-Concentration VOCs by Solid-Phase Microextraction Exposures to low-level VOCs in indoor environments were suspected to be related with “sick building syndrome”. The purpose of this study was to validate a new diffusive sampling device for VOCs based on the technique of solid-phase microextraction (SPME). Four different VOCs, including benzene, toluene, ethylenebenzene, and xylenes (BTEX), were tested in this research. Carboxen/Polydimethylsiloxane (CAR/PDMS) fiber was selected for the study. After the diffusive sampler was assembled, the performance of the designed method were validated at known concentrations of BTEX vapors which were prepared in gas bags and/or by a dynamic standard gas generation system. After sampling, the sampler was inserted into the injection port of gas chromatography/mass spectrometry (GC-MS) for thermal desorption and Selected Ion Recording (SIR) mode was used for sample analysis. The method detection limits were 0.21 ng (benzene), 0.026ng (toluene), 0.0028 ng (ethylenebenzene), and 0.159 ng (o-xylene), respectively which were determined by syringe injection of standard solutions. The desorption efficiency was 100% when the time for thermal desorption was 5 mins. The experimental sampling rates were (7.46?0.63)?10-3, (6.61?0.87)?10-3, (7.22?0.71)?10-3, and (7.39?0.84)?10-3 cm3/min, for benzene, toluene, ethylene, and o-xylene, respectively. The experimental sampling rates of BTEX were not affected by different temperatures (4℃~25℃) and wind velocities(0~50fpm). Relative humidity at 80% also had no effects on the sampling rates for benzene and ethylbenzene (compared to R.H. = 10%) while statistical differences were observed for toluene and o-xylene. Besides, the designed method was found to be able to collect BTEX effectively at instantaneous low-concentration (e.g., 5 min at 0.1 ppm) and sample stability test showed the recovery around 100?20% after 48 hours’ storage at 4℃. The designed diffusive sampling device for VOCs has both the advantages of passive sampling and SPME technique. Compared with other methods, the current designed method provides a more convenient and sensitive tool for the exposure assessments of indoor-low-level VOCs . |
