以飛秒雷射誘發多光子離子化質譜法與電子撞擊離子化質譜法分析人體呼氣中氣體分子及對離子化效率之比較

Abstract

本研究分別利用氣相層析電子撞擊式質譜儀(gas chromatography-electron ionization-mass spectrometry, GC-EI/ MS)以及飛秒雷射誘發多光子離子化飛行時間質譜儀(femtosecond laser-induced multiphoton ionization/time-of-flight mass spectrometry, FL-MPI/ TOFMS)研究並且比較非吸菸者／吸菸者呼吸氣體中成分的質譜資訊。藉由固相微萃取(solid phase microextraction, SPME)提升分析物訊號強度後，本研究能夠在人體呼氣樣品中檢測出40種以上的揮發性有機化合物(VOCs)其中有24種揮發性有機化合物可以被鑑定出來。GC-EI / MS利於偵測己烷(hexane)，乙脲(ethylurea)，甲苯(toluene)和檸烯(limonene)。相對的，FL-MPI/ TOFMS則利於偵測鄰二甲苯(o-xylene)，萘(naphthalene)和甲基丙基苯(methylpropyl benzene)等化合物。而有些化合物在兩種質譜儀中皆有被偵測到，例如丙酮(acetone)以及異戊二烯(isoprene)。除此之外，本研究亦利用FL-MPI/ TOFMS檢測同一名志願者吸菸後的呼氣樣品，發現其中含有有2,3-二甲基吡嗪(2,3-dimethly pyrazine)，2-甲基吡啶(2-methyl pyridine)和吡嗪(pyrazine)等化合物。GC-EI/MS和FL-MPI/TOFMS的組合，成功地為研究人體呼氣中的VOCs提供一種新的檢測方法。

Characteristic mass fragmentation of breathing gases from nonsmoker/smoker was investigated and compared by means of gas chromatography-electron ionization-mass spectrometry (GC-EI/MS) and femtosecond laser excited multiphoton ionization/time-of-flight mass spectrometry (FL-MPI/TOFM) methods, respectively. Solid phase microextraction (SPME) was used to improve the concentration levels. As a result, more than 40 types of volatile organic compounds (VOCs) in human breath were detected and 24 types of them were identified by database. The use of GC-EI/MS was useful for the detection of hexane, ethylurea, toluene, and limonene. In contrast to this, FL-MPI/TOFMS was useful for the detection of o-xylene, naphthalene, and methylpropyl benzene, etc. Some compounds were detected by either methods, including acetone and isoprene, etc. However, 2,3-dimethly pyrazine, 2-methyl pyridine, and pyrazines were found this time by FL-MPI/TOFM from the same volunteer after he smoked a cigarette. The combination of GC-EI/MS and FL-MPI/TOFMS was successfully to provide a new methodology for the study of VOCs from human breath.