本研究主要於發展微晶片電泳與電化學偵測之結合，在微晶片的製作過程中，首先利用微積電製程技術於矽晶圓的表面製造出微流道的陽模，再使用poly(dimethylsiloxane) (PDMS)採用造模法的方式翻模製造出微流道，本法的優點有材料成本較低、製作過程簡便適合大量製造等。就電化學偵測而言，本系統利用網版印刷碳電極作為工作電極，並將此工作電極垂直置於微流道之末端以進行偵測分析物，具有可簡單且快速的更換工作電極之優點。 此系統透過於PDMS的製作過程中混入的cellulose acetate以改善分離acetaminophen與p-aminophenol的拖尾現象，而系統在最佳化的條件下，溶液組成20mM 2-(4-Morpholino)ethanesulfonic acid (MES)緩衝溶液pH5.5，內含1mM 氯化鈉，以偵測電位900mV(vs. Ag/AgCl)偵測自電泳分離的acetaminophen與p-aminophenol，偵測時工作電極與流道末端距離為60μm，分離的條件為樣品注入時間3秒，分離電壓2000V，分離時樣品槽與樣品廢液槽所施加的電壓控制在分離電壓80%的水準，所得之分析特性分別為：p-aminophenol的線性範圍從5μM到1.25mM(R=0.999)，偵測靈敏度為0.32nA/μM，acetaminophen的線性範圍從10μM到1mM(R=0.995)，偵測靈敏度為0.17nA/μM，重複17次實驗操作對200μM p-aminophenol與acetaminophen水溶液的偵測，所得之相對標準偏差分別為3.22%與3.62%。 This research demonstrates the feasibility of using microchip for acetaminophen and p-aminophenol with thick film printed electrochemical detector. First, we used the microelectromechanical systems (MEMS) technology to create a positive pattern on the silicon wafer, and then the poly(dimethylsiloxane) (PDMS) microchannel was formed by casting. The PDMS owns many advantages such as low cost, readily mechanical processing and mass replication. For electrochemical detector, the working electrode was fabricated by screen printed technology and subsequently the electrode was mounted perpendicularly to the outlet of microchannel. The advantage of the electrode is easy and fast replacement. The peak spreading of acetaminophen and p-aminophenol was improved by blending 0.2% cellulose acetate for the PDMS. Acetaminophen and p-aminophenol was measured by using amperometry at the optimum condition at buffer solution: 20mM 2-(4-Morpholino)ethanesulfonic acid (MES) buffer pH5.5 containing 1mM sodium chloride; detection potential: 900mV (vs. Ag/AgCl); the distance between the working electrode and microchannel outlet : 60μm; injection time: 3s; the hold voltage in sample and sample waste reservoir during separation: 80% of separation voltage; separation voltage: 2000V. According to optimum operation conditions, the linear ranges of acetaminophen and p-aminophenol are obtained between 10μM to 1mM(R=0.995) and 5μM to 1.25mM(R=0.999), respectively. The sensitivities are 0.17nA/μM for acetaminophen and 0.32nA/μM for p-aminophenol. The detection limits of acetaminophen and p-aminophenol are 3.5μM and 1.8μM(S/N=3), respectively. The relative standard deviation of seventeen repetitive detections are 3.62% for acetaminophen and 3.22 for p-aminophenol.
