| Summary: | 碩士 === 國立臺灣科技大學 === 化學工程系 === 105 === In this study, two different electrochemical sensors were developed, aiming to be applied for onsite detection for metal ions and methylene blue, respectively. At the first part, the electrochemical sensors based on the anodic stripping voltammetry were developed for the detection of heavy metals, including zinc and copper ions. The aim of the second part of this study is to develop electrochemical sensors for DNA detection.
For first part of the thesis, two electrodes were applied for evaluating the sensitivity toward zinc and copper ions: (I) screen printed electrode (SPE), and (II) gold electrode (AuE). In order to enhance the sensitivity and the limit of detection (LOD), the electrode was modified with electrospun a-Al2O3 fibers mixed with polyaniline (PANI) (a-Al2O3-PANI). The functionalities, crystallinity, morphology of a-Al2O3 were characterized by ATR-FTIR, XRD, and FE-SEM, respectively. To detect zinc and copper ions by square wave anodic stripping voltammetry (SWASV). The a-Al2O3-PANI/SPE revealed a good sensitivity of 1.45 uA ppb-1 cm-2 toward zinc ions with the linear range of from 80 to 200 ppb, and the limit of detection of 24.33 ppb. On the other hand, the a-Al2O3-PANI/SPE and a-Al2O3-PANI/AuE revealed good sensitivity of 1.50 and 6.54 uA ppb-1 cm-2 toward Cu2+ ions, respectively. The linear range for the detection of Cu2+ was from 20-200 ppb on both electrodes, and the limit of detection was 7.70 and 2.14 ppb, respectively.
For the second part of the thesis, the surface of SPE was modified to prepare DNA sensor. In order to enhance the affinity between DNA and SPE, the electrode was modified with three different amine functionalities containing compounds: PANI, PEI, and APTES. The sensitivity and LOD (limit of detection) of the prepared sensors was determined toward methylene blue (MB). For the SPE decorated with PEI3(PEI3/SPE), the sensitivity for the detection of MB was 0.65 uA uM-1 cm-2,with the linear range from 10 to 50 uM, and the LOD of 74.0 uM. For the APTES/SPE, the sensitivity toward MB detection was 4.37 uA uM-1 cm-2 at lower concentration range from 1 to 10 uM. On the other hand, the sensitivity was 0.87 uA uM-1 cm-2 at higher concentration, from 10 to 50 uM, with the LOD of 4.83 uM.
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