| Summary: | 碩士 === 淡江大學 === 化學學系碩士班 === 95 === 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.
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