整合TEOS靜相及無電極電鍍加熱金層之微型分離管柱晶片應用於微型氣相層析系統之研究

Abstract

氣相層析系統為一標準之分析儀器，用以分離及檢測未知的混和氣體。由於其高解析度和高靈敏度，已被廣泛應用於食物檢測、環境監控以及藥物分析。但是，由於其體積過於龐大，無法達到可攜式以及即時檢測之目標；除此之外，過多的功率損耗，也是其缺點之一。因此，如何將其微小化達到可攜式的目標，以及降低系統的功率損耗，為目前重要的課題。 本論文利用微機電(Micro-electromechanical System, MEMS)製程技術開發一微型分離管柱晶片，並使用新穎之無電極鍍金法製備金加熱器於流道內，成功地整合加熱器及微型分離管柱晶片。相較於過去文獻所提出之金屬加熱器製備法，無電極鍍金法優點為不需要經過大型且昂貴的真空機台即可製備金加熱器，不僅具備較低之製備成本，且所製備出之金層可以分布於流道四周，相較於傳統半導體製程只能進行水平面塗佈，具有相當大的優勢。本研究使用之微型分離管柱晶片，結合DB-1靜相後可以成功地於250秒內分離如烷類、苯類等分子量較大之有機氣體。此外，本研究提出一稱為四乙氧基矽烷的多孔性化學結構材料作為靜相，用以分離分子量較低、無法藉由DB-1靜相而分離之混和氣體；以TEOS為靜相之微型分離管柱晶片成功地在300秒內分離4種醇類混和氣體。 本研究成功地提出之無電極電鍍法製備金加熱器不僅可以塗佈於流道四周、除去了過去烘箱的使用，也免除了其他外部加熱器的使用。而整合了此加熱器與微機電系統製作出之微型分離管柱晶片大幅地縮小了氣相層析系統分離步驟所佔據的體積。除此之外，TEOS靜相的使用使得微型分離管柱晶片成功地於2米流道內達成低分子量有機氣體分離並偵測，希望在未來能將此些應用嵌入於微型氣相層析系統中用於如酒測等等之即時量測上。

Gas chromatography (GC) is one of the best analytical methods to separate and analyze the unknown gas mixture. Because of the high resolution and sensitivity, a GC system has been widely applied to food processing, environmental monitoring, and medical diagnostic, etc. However, the size of a conventional GC is very large that can’t be carried for the point-of-test applications. Although having a great accuracy, the conventional GC is unable to do point-of-test analysis. In addition, high power consumption is also one of the disadvantages of a conventional GC. Therefore, miniaturizing the size of the GC and lower power consumption are important research topics in recent years. In this research, a micro-machined separation column (μSC) is fabricated by micro-electromechanical systems (MEMS) technologies. A novel electroless gold deposition method is utilized to fabricate a gold heater on the surface of the μSC channels. Compared to electroplating, this process is very simple and requires no vacuum based equipment, which has the advantages of not only lower cost but also capable of depositing the gold layer on all sides of the channels. With DB-1 stationary phase coated inside the μSC, our column is able to separate selected heavy hydrocarbons, such as alkanes or aromatics hydrocarbons in less than 250 seconds. Moreover, a porous chemical structure material called TEOS is developed as a novel stationary phase for light mixture’s separation, which cannot be achieved by utilizing DB-1 as stationary phase. With a programmed temperature control, μSC with TEOS as stationary phase can separate the alcohols easily in less than 300 seconds. The electroless gold deposition method not only eliminates the requirement of the heating element, but also provides great uniformity of the Au film on all sides of the channels. With the combination of the Au heater and micro-machined column, the size of the separation process is successfully reduced. In addition, the development of the TEOS stationary phase is indeed a breakthrough for light hydrocarbons’ separation with 2-meter μSC. It could apply to point-of-test measurements such as driving under the influence (DUI) detection in the future by integrating this μSC to a portable GC or Micro-GC system.