可調變電場吸氣式離子遷移譜儀研究

A Study of Swept-Field Aspiration Condenser as an Ion Mobility Spectrometry

薛建富(Chien-Fu Hsueh)

指導教授 ： 鄭桂忠

國立清華大學/電機資訊學院/電機工程學系/碩士(2014年)

摘要

氣體辨識一直是一重要且切關生活的研究課題，不僅是在科學研究上常以氣相分析不明化學物質，在國防維安上常利用氣體辨識偵測爆裂物、毒氣、毒品，此外大至環境監測，小至醫學檢驗、個人健康照護也常看見氣體辨識系統的身影。
本研究所探討的氣體辨識技術是離子遷移譜儀，離子遷移譜儀自70年代開始發展至今已是一成熟且可靠的技術，普遍應用於機場維安、化學戰劑及有毒工業化合物偵測。離子遷移譜儀是一藉由電場加速氣體離子團以達到分析位置氣體成分的技術，傳統的離子遷移譜儀在均勻電場中加速氣體離子團並記錄其飛行時間用以分析資訊，一般常見的離子遷移譜儀具有5至12公分長之氣體離子飄移管，加以300V/cm~600V/cm的電場，因此不論是在體積及電壓需求上皆會使其應用範圍受到限制。
本研究之基礎是基於Heikki Pakkanen 在 1991 年提出用於化學戰劑偵測用之多頻道吸氣式離子遷移譜儀，在此種離子遷移譜儀之電場方向與氣流方向垂直，所需之外加電場電壓視其設計需求，一般約在數十伏特之上下，此種構型之離子遷移譜儀雖具有低電壓需求及方便製造、維護之優點，但其對氣體之辨識能力並不如傳統分析氣體飄移時間之離子遷移譜儀優秀，為提升其氣體辨識能力，本研究加入可調變電場機制，使其能獲取代測氣體中完整的氣體離子資訊，並配合Discrete Tammet Transform對量測得之訊號進行分析。此外本研究對吸氣式飄移管中之氣體離子團運動特性提出了基於氣體擴散效應的分析及轉換方程，此轉換方程與Discrete Tammet Transform相比更加貼近氣體飄移管中離子的分布情形，幫助我們了解吸氣式離子遷移圖譜的訊號特性。

關鍵字

離子遷移圖譜

並列摘要

IMS (Ion Mobility Spectrometry) is a well-known gas analytical technique for ionized gas molecular. In the past decades, IMS has been widely used for detecting hazardous compounds, explosives and chemical warfare agent. Recently, IMS also established a strong foot hold in medical application like detection of drug abuse, clinical examination and personal health care.
In this research, we established an aspiration condenser as an ion mobility spectrometry. Ionized gas molecular are separated by electric field intersect with carrier gas flow. Gas recognition in aspiration condenser usually done by analyzing multi-channel data. Heikki Pakkanen proposed a multi-channel aspiration condenser for CWA(chemical warfare agent) detection in 1991 and become a popular solution for military purpose. Although aspiration condenser is good at chemical compounds fast detection, the poor analyzing and gas recognition ability limit it application. The aspiration condenser designed in this research is based on the model proposed by Emilio Sacristan and Andro A. Solis. Swept-field mechanism and Discrete Tammet Transform increased the gas recognition ability in aspiration condenser. We introduce the effect of Brownian motion in aspiration condenser and modified the analyze process and transform equation. The new transform equation had been examed with experiment and the result shows Brownian motion has unnegligible effect in aspiration condenser.

並列關鍵字

Ion mobility spectrometry

參考文獻

[13] Blanchard, William C,” Electric field control in ion mobility spectrometry” pat. No. US 4855595, 1989

[1] Gushinder Kaur-Atwal, “Chemical standards for ion mobility spectrometry: a review”, Int. J. Ion Mobil. Spec. (2009) 12:1–14

[2] Mikko Utriainen, “Combining miniaturized ion mobility spectrometer and metal oxide gas sensor for the fast detection of toxic chemical vapors”, Sens. Actuat. B-chem. 2003,93(1-3), pp. 17-24

[5] Tapio Kotiaho, Membrane inlet ion mobility spectrometry for on-line measurement of ethanol in beer and in yeast fermentation, Anal Chem. Acta 1995,309 pp.317-325.

[6] Elham Jazan, Hadi Mirzaei, Direct analysis of human breath ammonia using corona discharge ion mobility spectrometry, Journal of Pharmaceutical and Biomedical Analysis, Volume 88, 25 January 2014, Pages 315-320, ISSN 0731-7085