A graphene composite electrochemical sensor for determination of caffeine

摘要 本研究目的是以石墨烯(rGO)做為主要感測器材料並且對咖啡因做測量以及探討。 本研究分成三部份，第一部份使用Hummers method的製備方法，將氧化石墨烯(GO)還原成為石墨烯(rGO)，藉由UV-Vis光譜儀以及循環伏安法測量，以證實此方法確實將氧化石墨烯(GO)還原成石墨烯(rGO)使用。 第二部份藉由Nafion 高分子分散石墨烯(rGO)並修飾於玻璃碳電極上，以應用於咖啡因感測器。並且使用原子力顯微鏡觀察檢視rGO / Nafion 修飾電極的表面形貌，之後在從圖中觀察到rGO均勻分散在電極表面，接著使用循環伏安法來偵測rGO / Nafion/GCE修飾電極對於咖啡因之電化學特性。經實驗後發現使用rGO / Nafion / GCE修飾的電極比未修飾的GCE電極擁有更好的電流信號，顯示rGO具有良好的電催化效果。 第三部份使用安培法來研究以rGO / Nafion / GCE製備的修飾電極的電化學特性。並且對此咖啡因感測器作干擾物測試和真實樣品檢測，以證實此感測器可避免抗壞血酸、葡萄糖以及檸檬酸的干擾以及可運用在真實樣品之檢測。Abstract Graphene (rGO)for the caffeine determination usingas a sensor material was measured and discussed. The first part is preparation graphene (rGO) and measuring graphene oxide (GO) is reduced to graphene (rGO) by UV-Vis spectroscopy and cyclic voltammetry. The result showed that graphene oxide (GO) is already reduced to graphene (rGO). Another is, investigating the surface morphology of rGO / Nafion modified electrode by using atomic force microscope. In addition,In addition, it made use of cyclic voltammetry determined rGO / Nafion modified electrode to pH, electrode composition, scan rate and electrochemical properties and obcerved the what of the effect on rGO / Nafion modified electrode. Finally, the study using amperometry method investigated the electrochemical properties of modified electrode rGO / Nafion / GCE properties. Besides, disruptors and real sample of testing for the rGO / Nafion modified electrode and make sure that the sensor isavoided interfering of ascorbic acid, citric acid and glucose and using it by detected real sample. The sensor shows greatpromise for simple and sensitive determination of caffeine.總目錄 摘要....................................................I ABSTRACT...............................................II 第一章 緒論..............................................1 1.1前言.................................................1 1.2 分析物簡介以及文獻探討.................................2 1.2.1分析物簡介..........................................2 1.2.2文獻探討............................................4 1.3 感測器簡介...........................................11 1.3.1 物理感測器.........................................11 1.3.2 化學感測器.........................................11 1.3.2.1 電化學感測器................................12 1.3.2.2 信號傳感器..................................12 1.4 石墨烯簡介質與應用....................................13 1.4.2 石墨烯的製備 .......................................14 1.5 全氟磺酸聚合物簡介....................................16 1.6 電化學原理與方法......................................17 1.6.1 循環伏安法(CYCLIC VOLTAMMETRY).....................17 1.6.2安培法(AMPEROMETRY)................................20 1.7 咖啡因電化學反應機制...................................22 第二章 實驗方法與步驟......................................23 2.1實驗藥品..............................................23 2.2實驗儀器..............................................24 2.3實驗步驟..............................................25 2.3.1 石墨烯氧化物(GRAPHRNR OXIDE，GO)製備................25 2.3.2 石墨烯 (GRAPHRNR，RGO)製備.........................25 2.3.3 玻璃碳電極(GCE)前處理...............................26 2.3.4 石墨烯/全氟磺酸聚合物複合薄膜電極製備以及實驗步驟........26 第三章 結果與討論.........................................28 3.1石墨烯氧化物(GO)還原成石墨烯(RGO)之探討..................28 3.1.1 紫外光/可見光(UV-VIS)吸收光譜儀......................28 3.1.2 原子力顯微鏡(AFM)..................................30 3.2 RGO/NAFION複合薄膜玻璃碳電極咖啡因感測器電化學分析探討.....32 3.2.1循環伏安法..........................................32 3.2.2最佳克數............................................36 3.2.3 PH值對電極影響之探討................................38 3.2.4 掃描速率對電極影響之探討.............................40 3.3 RGO/NAFION複合薄膜玻璃碳電極咖啡因感測器真實樣品分析探討...42 3.3.1安培法對電極之最適電壓探討.............................42 3.3.2文獻資料比較........................................44 3.3.3干擾物測試..........................................45 3.3.4真實樣品檢測........................................46 第四章 結論與未來展望......................................50 4.1 結論................................................50 4.2 未來展望.............................................51 第五章 參考文獻...........................................5