以固相微萃取技術發展偵測室內MVOCs之方法

Abstract

本研究利用固相微萃取技術(Solid-Phase Microextraction, SPME)免溶劑脫附與操作簡單等優點，發展多種MVOCs同步偵測之採樣分析方法，以便在未來能更方便且準確地評估室內MVOCs濃度並推估室內環境中黴菌生長狀況，進而提高室內空氣品質。 本研究依據文獻記載選擇存在於室內環境中之MVOCs進行測試(包括: 1-butanol、1-octen-3-ol、2-methyl-1-propanol、2-heptanone, 2-pentylfuran、2-hexanone與3-methyl-1-butanol)。研究中使用所選定的65 μm PDMS/DVB纖維搭配動態暴露系統，使纖維暴露於固定流速下( 17.77 cm3/min)進行外推式的採樣，並利用已知濃度的MVOCs進行不同暴露時間之測試，再利用氣相層析質譜儀(GC/MS)進行樣本的脫附與分析。 本研究所設計之SPME纖維外推採樣方法對多種MVOCs同步暴露與偵測後發現，除了隨著暴露濃度與暴露時間乘積的增加、纖維上MVOCs之採集量將增加外，在相同濃度變化條件下，纖維對MVOCs的採樣率會隨著暴露時間的增加而變小。另外，在相同暴露時間變化條件下，纖維對MVOCs的採樣率亦會隨著暴露濃度的不同而呈現差異；上述觀察顯示，纖維上之MVOCs採集量同時受到暴露濃度、暴露時間、及暴露濃度與暴露時間乘積的共同影響。 本研究利用回歸分析後發現，纖維上各物質之採集量與暴露濃度及暴露時間之乘積呈現分段線性關係，而所得之採樣率如下：2-methyl-1-propanol 0.06~1.21 cm3/s (採樣時間: 10秒~40分鐘)、1-butanol 0.05~1.75 cm3/s (採樣時間: 10秒~60分鐘)、1-octen-3-ol 0.50~0.98 cm3/s (採樣時間: 20秒~40分鐘)、2-heptanone 0.41~1.04 cm3/s (採樣時間: 10秒~60分鐘)、2-pentylfuran 0.55~0.97 cm3/s (採樣時間: 10秒~60分鐘)、2-hexanone 0.27~1.07 cm3/s (採樣時間: 10秒~60分鐘)以及3-methyl-1-butanol 0.26~2.19 cm3/s (採樣時間: 20秒~40分鐘)。此外，儀器偵測極限為0.20到1.56 ng/μL，方法偵測極限為1.15到3.74 ng/μL。本研究所設計之MVOCs採樣方法具有免溶劑脫附、樣本前處理時間短、組合簡單、攜帶方便、分析時間短等優點；配合GC的使用，未來可實際應用於室內空氣品質之監測。

Indoor air pollution is a major problem of public health nowadays because people usually spend more than 80% of time indoor. Fungus is an important indoor air pollutant and is known to be a fundamental allergen of asthma. Microbial volatile organic compounds (MVOCs) which are the metabolites of fungi can also be used to relate the presence of fungi even there is no spore. To improve the quality of indoor air, setting standards for indoor biological hazards are very important. Therefore the purpose of this study is to develope the sampling and analysis technique for indoor MVOCs based on solid-phase microextraction (SPME) device. SPME technique was utilized as a rapid air sampling sampler while its performances on major indoor MOVCS, including 1-butanol, 1-octen-3-ol, 2-methyl-1-propanol, 2-heptanone, 2-pentylfuran, 2-hexanone and 3-methyl-1-butanol were validated. 65 μm PDMS/DVB fiber was selected. Known concentration of MVOCs were generated in dynamic vapor generation system for the validations of SPME rapid air sampling samplers. After sampling, the sampler was inserted into the injection port of gas chromatography with mass spectrometry (GC/MS) for thermal desorption and analysis. The results showed that the desorption efficiency was 100% when the time for thermal desorption was 1.5 min. It was also found that different ranges of linearity were observed for all the MVOCs at different sampling conditions. Under the sampling time of 10 seconds to 60 minutes, the experimental sampling rates were 0.05~1.75 cm3/s, 0.41~1.04 cm3/s, 0.55~0.97 cm3/s and 0.27~1.07 cm3/s for 1-butanol, 2-heptanone, 2-pentylfuran and 2-hexanone, respectively. Under the sampling time of 20 seconds to 40 minutes, the experimental sampling rates were 0.50~0.98 cm3/s and 0.26~2.19 cm3/s for 1-octen-3-ol and 3-methyl-1-butanol, respectively. The experimental sampling rates was 0.06~1.21 cm3/s for 2-methyl-1-propanol under the sampling time of 10 seconds to 40 minutes. Moreover, the instrumental detection limit (IDL) ranged between 0.20 and 1.56 ng/μL while the method detection limit (MDL) ranged between 1.15 and 3.74 ng/μL. The designed rapid air sampling device for MVOCs has the advantages of SPME technique which can be used for monitoring indoor air quality (IAQ) in the future.