製備多層奈米碳管複合薄膜修飾電極偵測膽固醇,過氧化氫和苯酚

Fabrication of Multiwalled Carbon Nanotube Composite Film Modified Electrode for Electrochemical Determination of Chlesterol, H2O2 and Phenol

楊政祐(Jeng-You Yang)

指導教授 ： 陳生明

國立臺北科技大學/工程學院/化學工程研究所/碩士(2011年)

https://doi.org/10.6841/NTUT.2011.00014

摘要

第一部分：利用膽固醇氧化酵素(ChOx)和多層奈米碳管(MWCNTs)一起複合在玻璃碳電極上形成膽固醇氧化酵素與多層奈米碳管複合膜修飾電極。多層奈米碳管除了可以增加電極的表面覆蓋率(Γ)還可以增強過氧化氫在電化學分析上的電活性。
　　膽固醇氧化酵素與多層奈米碳管複合膜的表面覆蓋率為1.86×10-11 mol cm-2比只有多層奈米碳管修飾薄膜和只有膽固醇氧化酵素修飾薄膜來得還高。我們利用Ep = K – 2.303(RT/nF)logv和膽固醇氧化酵素為兩個電子轉移一起來計算可得到膽固醇氧化酵素與多層奈米碳管複合膜修飾電極的電子轉移效率為0.22，電子轉移常數(Ks)為0.0269-1。並且利用SEM 可得到奈米碳管修飾電極和膽固醇氧化酵素修飾電極還有膽固醇氧化酵素與多層奈米碳管複合膜修飾電極間的表面特性有明顯的差異。利用循環伏安法(CV)和計時安培法(AMP)可得到膽固醇氧化酵素與多層奈米碳管複合膜修飾電極的電催化活性比單只有奈米碳管修飾電極的電催化活性來得佳。膽固醇氧化酵素與多層奈米碳管複合膜修飾電極對膽固醇的偵測靈敏度為1261.74 μA mM-1 cm-2偵測範圍為4.68×10-5 – 2.79×10-4 M偵測極限為4.68×10-5 M。
第二部分：本部份的研究多層奈米碳管(f-MWCNT )/具二苯胺(PDPA)薄膜修飾電極對苯酚(Phenol)電催化反應的特性。DPA 在5m MH2SO4溶液中電聚合在MWCNT薄膜修飾電極上，利用電子掃描顯微鏡觀察表面形態和EIS研究修飾電極表面電子轉移現象。循環伏安法得到氧化電位在 -0.68V，且f-MWCNT/.PDPA薄膜修飾電極對phenol的陽極電流比f-MWCNT薄膜修飾電結的陽極電流大2.93倍，由計時安培法可得知其線性範圍在9.8 μM to 80 μM。
第三部分：我們利用官能基化的多層奈米碳管(f-MWCNT)和食用色素藍色1號(BB)發展出一個能對光有反應且對H2O2做偵測的修飾薄膜。我們將f-MWCNT/BB修飾於ITO玻璃上來對其表面性質(AFM、SEM)做探討，並且利用EIS和UV一起來對f-MWCNT/BB的特性做探討，經由實驗證明，f-MWCNT/BB修飾薄膜對H2O2有良好的偵測效果。

關鍵字

多層耐米碳管 ； 膽固醇氧化酵素 ； 修飾電極 ； 電化學分析 ； 膽固醇

並列摘要

Part I：A cholesterol biosensor of ChOx/MWCNTs containing multiwall carbon nanotubes (MWCNTs) and cholesterol oxidase (ChOx) has been successfully synthesized on glassy carbon electrode (GCE). The presence of MWCNTs not only enhances the surface coverage (Γ) but also exhibits a promising enhanced electrocatalytic activity to hydrogen peroxide. It is stable, pH-dependent, and electroactive as produced on electrode surface. The average surface coverage (Γ) was estimated about 1.86×10-11 mol cm-2 higher than both of MWCNTs and ChOx modified electrodes. Using the equation Ep = K – 2.303(RT/nF)logv and the two electrons transferred for ChOx a charge transfer coefficient 0.22 was obtained. An apparent surface electron transfer rate constant (Ks) 0.0269 s-1 was estimated for the redox peaks. Compared with the SEM images of the MWCNTs/GCE and ChOx/GCE, the ChOx/MWCNTs film shows significant the surface morphology. The electrocatalytic responses of ChOx/MWCNTs film were investigated with various analytes by cyclic voltammetry (CV) and amperometry (AMP). Compared with bare electrode and ChOx/GCE, the ChOx/MWCNTs/GCE has better electrocatalytic current response to cholesterol. This sensor shows excellent performance with a sensitivity of 1261.74 μA mM-1 cm-2, a linear range of 4.68×10-5 – 2.79×10-4 M, and a detection limit of 4.68×10-5 M.
　　Part II：In this study I report the electrochemical oxidation of phenol at a multi-walled carbon nanotube (MWCNT)/poly diphenylamine (PDPA) composite film modified glassy carbon electrode (GCE). PDPA was polymerized on the MWCNT modified GCE by cyclic voltammetry (CV) in 5 M H2SO4. The surface morphology of MWCNT/PDPA was studied using Scanning Electron Microscope (SEM). The interfacial electron transfer phenomenon at the modified electrode was studied using electrochemical impedance spectroscopy (EIS). The MWCNT/PDPA composite film showed good electrocatalytic behavior towards the oxidation of phenol in pH 7. Phenol showed a well defined anodic peak at 0.68 V (vs. Ag/AgCl electrode). The MWCNT in MWCNT/PDPA film enhanced the anodic peak current by 2.93 times than that of GCE/MWCNT electrode. The peak current increased linearly with phenol concentration. The amperometric determination of phenol at the composite film modified electrode showed linear range from 9.8 to 80 μM. This result shows that the proposed composite electrode may be developed for potential application in real sample analysis.
Part III：A novel phtoelectrocatalytic response for the determination of hydrogen peroxide (H2O2) by functionalized multi-walled carbon nanotubes (f-MWCNT) with brilliant blue FCF (BB) modified electrode has been developed. f-MWCNT/BB modified electrode has been synthesized on glassy carbon electrode (GCE) and indium tin oxide (ITO). We have studied the surface morphology of the modified ITO electrode using scanning electron microscopy (SEM) and atomic force microscopy (AFM), which revealed that BB is coated on f-MWCNTs. electrochemical impedance spectroscopy (EIS) and UV-visible absorption spectrophotometry (UV-vis) have been used to investigate the brilliant blue FCF (BB) film. The cyclic voltammetry(CVs) has been used for the measurement of electroanalytical properties of analytes by means of modified electrodes. The presence of f-MWCNTs enhances the surface coverage (Γ) and stability. The modified electrode also exhibits a promising enhanced electrocatalytic activity of H2O2. The sensitivity values of f-MWCNTs/BB modified glassy carbon electrode are higher than the values which are obtained for only BB and f-MWCNTs modified electrode. Finally, typical amperometric curve has been used for the detection of H2O2 at f-MWCNTs/BB modified electrode.

並列關鍵字

Multiwall carbon nanotubes ； Cholesterol oxidase ； Modified electrodes ； Electrocatalysis ； Cholesterol

參考文獻

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