| Summary: | 碩士 === 國立成功大學 === 化學工程學系 === 104 === Firstly, three-dimensional (3D) reduced graphene oxide-carbon nanotube (rGO-CNT) nanocomposite was fabricated via the electrochemical reduction of graphene oxide-carbon nanotube (GO-CNT) on the screen printed carbon electrode (SPCE) to yield the rGO-CNT/SPCE for the electrochemical detection of phoxim. The presence of carbon nanotubes (CNTs) could lead to the formation of 3D structure, making the surface area of rGO can be utilized more efficiently to improve the sensitivity. It was demonstrated that CNTs were uniformly dispersed on GO, and GO has been electrochemically reduced to rGO. The electrochemical detection of phoxim on rGO-CNT/SPCE was performed in 0.1 M phosphate buffer at pH 7.0 by differential pulse voltammetry. A linear concentration range of 0.005~5 μM with a limit of detection (LOD) of 0.002 μM was obtained. For the detection of real samples and interference test, rGO-CNT/SPCE also exhibited an excellent performance. This revealed that it indeed could be used for the electrochemical detection and environmental monitoring of organophosphate pesticides. Secondly, β-cyclodextrin-modified graphene quantum dots (βCD-GQD) of about 9 nm were synthesized by the direct heating of citric acid and βCD at 200oC for the fluorescent detection of p-nitrophenol. The modification with βCD could significantly enhance the fluorescence intensity of GQD. Furthermore, for the fluorescent detection of by βCD-GQD, two linear concentration ranges of 0.1~7.5 μM and 7.5~100 μM with a LOD of 0.093 μM were obtained. The performance was significantly better than the un-modified GQD, revealing the resulting βCD-GQD indeed could be utilized in the fluorescent detection of toxic organic contaminants.
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