多維度分析方法用於動態樣品監測之開發

Abstract

許多化學反應具有非勻相及動態的特性，為了探究此類型的系統，開發具有空間及時間解析能力之分析方法是不可或缺的。另一方面，若將含有複雜基質的樣品直接以質譜方法分析，除了容易污染儀器之外，離子抑制效應亦會造成不良的分析結果，因此，樣品前處理的步驟變得相當重要。在此篇論文中，我們開發了兩種分析平台，分別可用於非勻相以及動態樣品的偵測。 在第一項研究中，我們運用數位相機與電腦螢幕，建構了一個具有時間與空間解析能力的光譜影像平台，並展示了其於觀測化學振盪反應（Belousov-Zhabotinsky 反應與Old-Nassau反應）的應用。我們將電腦螢幕當作可見光源，利用自製的程式控制使其在三個不同顏色（波長）來回變換，並以數位相機作為偵測器紀錄光源被樣品吸收的情形。在實驗結果中，能夠清楚地觀察因振盪反應產生的化學波前，以及化學反應產生的沈澱物將光線散射的現象。此光譜影像系統不僅成本低廉，並且成功地捕捉了動態樣品的時空特性。 在第二項研究裡，我們開發了一套自動化液相萃取系統，其結合了低成本的開源控制器（例如：Arduino與Netduino）來控制整個萃取過程，並利用大氣游離法進行萃取物的質譜分析。在真實的應用上，我們將該系統運用在兩種常見止痛藥的溶解測試之化學分析，並成功地監測了藥物溶解的過程長達10個小時。藥物溶解的實驗結果透過數學函式分析其動力學特性。此外，該系統的控制器能夠藉由不同管道與使用者溝通，例如：螢幕顯示、網頁、聲音及簡訊，這些功能使得這個系統具備了實現物聯網的潛力。

Many chemical processes possess intrinsic heterogeneous or dynamic properties. In order to study these systems, techniques that enable spatial and temporal characterization of the samples are required. On the other hand, mass spectrometric analysis of complex samples is often challenging and requires proper sample pre-treatment. Here, we have developed two analytical methods for two kinds of dynamic samples. In the first study, we constructed a system implementing a digital camera and a computer display to perform time-lapse spectral imaging of two model oscillating reactions. The display serves as a multi-wavelength light source while the camera records distribution of the light transmitted through a two-dimensional non-homogeneous dynamic sample (reaction mixture). The display alternately relays light of different wavelength onto the sample. During the first demonstration of the system, the Belousov-Zhabotinsky oscillating reaction and the Old Nassau (Halloween) clock reaction were investigated. Chemical front formation could be observed for the analytes absorbing light at one of the three wavelength bands. The proposed spectral imaging system is cost-efficient and succeeds in capturing some spatiotemporal features of dynamic mixtures. In the second study, an automated on-line liquid-liquid extraction system was developed to enable unsupervised repetitive treatment of dynamic samples and instantaneous analysis by MS. It incorporates inexpensive open-source microcontrollers (Arduino and Netduino) to guide the extraction and analysis processes. Extracts are automatically transferred to the ion source by implementing the Venturi pump. To exemplify its usefulness in real-world applications, the system was applied in chemical profiling of the pharmaceutical formulation dissolution process. Temporal dissolution profiles of commercial analgesic tablets were recorded during 10 hours. The fitted extraction-MS datasets provide kinetic characteristics of the dissolution process. Furthermore, the electronic control unit of this system interacts with the operator via touch screen, internet, voice and short text messages. It is helpful when launching long-term measurements. Due to these interactive features, the platform brings the concept of the Internet-of-Things to the chemistry laboratory environment.