發展存在於液相、固相以及吸附於表面的有機揮發物之分析方法

在具揮發性之有機分析物通過層析/質譜儀前，通常會牽涉到將分析物攜至氣相的過程。特別是當有機揮發性物質廣泛存在於食品、土壤與人體基質中，有效率且可再現的萃取方法即顯得重要。在這項研究中，我們開發了針對氣相有機揮發物的萃取技術與吸附於皮膚表面有機揮發物的取樣方法，萃取物可直接注入質譜或氣相層析質譜儀做檢測。在第一個研究中，藉由小液珠(<10μm)移除氣相分子來萃取有機揮發物質，萃取溶液之冷霧是由超音波霧化器產生。於常壓條件下，冷霧朝盛裝樣品之容器上空移動，進而以些微的壓力差將樣品內揮發性物質導入冷凝管。在緩慢經過樣品上空時，微小的液珠對樣品上空的揮發性物質進行萃取，而被萃取的揮發性物質會在冷凝管中冷凝，收集之冷凝液得以直接注入質譜儀或氣相層析質譜儀進行分析。樣品於萃取前後濃度之間的關係在理論上和實驗上都得到了驗證，而有些複合效應也被測試與討論。此方法也被應用於複雜的液態和固態樣品中特定物質之定性分析與酯化反應。於第二個研究中所開發之簡易皮膚取樣技術證實了廣泛應用的護膚產品(吸油面紙)可以從皮膚表面提取足量的化學殘留物，以進行後續的色層分析。分析樣品的製備簡單且僅需數分鐘完成。我們以市售防蚊液作為本研究之示範樣品。防蚊液於不同取樣時間上噴灑在豬皮與人的皮膚上，研究數據顯示皮膚表面之防蚊液成分的釋放(基於蒸發、吸收及/或分解)。此研究提供一個非侵入性偵測外用藥物和化妝品的方法。在此論文所發表的兩種方法皆為簡易、快速，及有效的揮發性化合物分析方法，它們的應用可以進一步擴展，以滿足食品，化妝品和藥物化學的特定要求。

關鍵字

揮發性有機化合物；萃取；冷霧；吸油面紙

並列摘要

Analysis of volatile organic compounds (VOCs) in solid or liquid samples often involves transferring those analytes into the gas phase prior to separation/detection by chromatography and/or mass spectrometry. Especially, when VOCs are present in complex matrices such as food, soil and human skin, it is necessary to extract these compounds efficiently and reproducibly. In this work, an extraction method for gas-phase VOCs and a sampling method targeting VOCs adsorbed on skin surface have been developed. These methods are compatible with direct infusion mass spectrometry (MS) or gas chromatography (GC) coupled with mass spectrometry. In the first project, a technique of extracting VOCs by scavenging gas-phase molecules with tiny liquid droplets (< 10 μm) was introduced. A ¬cool mist of the extracting solvent is generated by an ultrasonic transducer, transferred to the headspace of the sample chamber under atmospheric conditions, and pushed by a small pressure difference toward a condenser. By slowly passing over the sample, the microdroplets extract VOCs present in the sample headspace, and they coalesce in a cooled zone. The condensed liquid was collected for analysis by direct infusion MS or GC-MS. The relationship between the sample concentration and the extract concentration was verified theoretically and experimentally. Some of the possible confounding effects were tested and discussed. The technique was subsequently applied to qualitative analysis of selected complex samples in liquid and solid phase as well as an esterification reaction. In the second project, a simple skin sampling technique was developed. We show that a widely available commercial skin-care product (oil-control blotting paper) can lift chemical residues from skin surface in the amounts sufficient for subsequent chromatographic analysis. Sample preparation is straightforward and takes only few minutes. In this study, a commercially available mosquito repellent was used as a model sample. It was dispersed on porcine or human skin at different times prior to sampling. The datasets allowed us to characterize the kinetics of repellent ingredient release (due to evaporation, absorption, and/or decomposition) from the skin surface. This method provides a non-invasive way to detect topical drugs and cosmetics. The two methods disclosed in this thesis are simple, fast, and enable efficient analysis of various VOCs. Their applications can be further extended to fulfill specific requirements of food, cosmetic, and pharmaceutical chemistry.

並列關鍵字

volatile organic compounds ； extract ； cool-mist ； blotting paper

參考文獻

1. Volatile Organic Compounds (VOC). Luxembourg: Eurofins Scientific. Available at: https://www.eurofins.com/voc.aspx. Retrieved Jul 03,2012. (accessed January 30, 2018 )

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