利用奈米碳管結合染料的電化學研究

The Electrochemical Research of Carbon Nanotube – Dye Composite Electrodes

丁子瑋(Tzu-Wei Ting)

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(2009年)

摘要

本研究第一部份，主要是發展出分析過氧化氫的一種生物感測器。此生物感測器的製備，是由ormosils和亞甲基綠結合多層奈米碳管和過氧化酶所構成的。其中ormosils是指3-aminopropyltrimethoxysilane(APTMOS)、
2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane(EETMOS)和 phenyltrimethoxysilane(PHTMOS)所結合而成的。APTMOS可以強化ormosils結構的親水性，PHTMOS和EETMOS則會增加ormosils結構中的物理和機械強度。藉由使用掃描式電子顯微鏡(SEM)、紫外線可見光譜(UV-VIS)和電化學方法，來檢驗此修飾電極的特性。循環伏安法和安培電流的測量，可以證明亞甲基綠和過氧化酶與多層奈米碳管結合在一起時，會顯示出好的穩定性及可以在酵素和電極中有效率的電子轉移，也可以有效地促進過氧化氫的還原電催化及降低其還原反應的過電壓。本研究製備出的生物感測器在最適化的條件下，低於十秒內，過氧化氫有著很快速的反應和從5x10-7到2x10-5 M有極佳的線性濃度範圍，且其偵測極限是0.5 µM。同時，也會研究此生物感測器對pH濃度、酵素量以及在標準狀態下電位的影響。而本研究所發展出的生物感測器，很方便使用且顯示出高選擇性及好的穩定性。
第二部份為利用ormosils、亞甲基藍和Nafion結合單層奈米碳管和過氧化酶製備出高靈敏度、快速偵測、高穩定性的過氧化氫生物感測器。而Nafion會擴散到ormosils的修飾膜裡，去強化電子轉移的功能。過氧化酶則會吸附到單層奈米碳管/ormosils的修飾電極表面上，而藉由單層奈米碳管的多孔性來增加有效的表面積，使修飾電極性能可以達到最佳化。本研究將使用掃描式電子顯微鏡、原子力顯微鏡和紫外線可見光譜儀來探測單層奈米碳管/ormosils修飾電極的特性。此外，藉由循環伏安法和計時安培法來測量此生物感測器，使其性能達到最佳化。同時，也會系統化地研究此生物感測器對不同pH值濃度、酵素量、和應用電位的影響。而實驗的結果也顯示出此複合膜修飾電極，可供過氧化酶固定在修飾電極上。且在最適化的條件下，偵測過氧化氫會顯示出低的偵測極限(0.3 µ M)、高穩定性、好的再現性及出色的線性濃度範圍(5x10-7到1x10-4 M)。
第三部份則利用官能基化的多層奈米碳管與結晶紫染料結合在一起，並吸附在玻璃碳電極上。此修飾膜經照光下，不但會降低電子轉移阻抗，同時也會增加氧還原的電催化活性。而此官能基化的修飾膜會使用紫外線可見光譜儀和傅立葉紅外線來檢測其吸收峰和官能基。而氧的電催化反應會使用循環伏安法和旋轉環-碟電極(RRDE)來做研究。從電催化上來做探討，經照光的結晶紫-多層奈米碳管修飾膜，氧還原電流訊號比多層奈米碳管及没照光的結晶紫-多層奈米碳管修飾膜還要來的大。

關鍵字

單層奈米碳管 ； 多層奈米碳管 ； 亞甲基綠 ； 亞甲基藍 ； 結晶紫 ； ormosils ； 過氧化酶過氧化氫 ； Nafion

並列摘要

Part I：A novel amperometric biosensor for the analytical determination of hydrogen peroxide was developed. The fabrication of the biosensor was based on the coimmobilization of horseradish peroxidase (HRP), methylene green (MG) and multiwalled carbon nanotubes within ormosils; 3-aminopropyltrimethoxysilane (APTMOS), 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (ETMOS) and phenyltrimethoxysilane (PHTMOS). APTMOS determined the hydrophilicity / hydrophobicity of the ormosils and PHTMOS and ETMOS increased the physical and mechanical strength of the ormosil matrix. The ormosil modified electrodes were characterized with SEM, UV-vis spectroscopy and electrochemical methods. Cyclic voltammetry and amperometric measurements demonstrated the MG coimmobilized with HRP in this way, displayed good stability and could efficiently shuttle electrons between immobilized enzyme and electrode, and MWCNTs facilitated the electrocatalytic reduction of H2O2 at reduced over potential. The prepared biosensor had a fast response of H2O2, less than 10s, and excellent linear range of concentration from 5x10-7 to 2x10-5M with the detection limit of 0.5µM (S/N=3) under the optimum conditions. At the same time, the influence of solution pH, effect of enzyme amount, steady-state applied potential on the biosensor was investigated. The preparation of the developed biosensor was convenient and showed high sensitivity with good stability.
PartⅡ：A biosensor for the detection of hydrogen peroxide has been developed. The feature of biosensor is highly sensitive, fast responding and stable. It is fabricated by using coimmobilizd the SWNT and methylene blue (MB) derived organically modified sol-gel (ormosils); Nafion was dispersed within the ormosil matrix to enhance the electron transportation in the modified film. Horseradish peroxidase (HRP) was diffusionally adsorbed onto the SWNT/ormosil modified electrode surface. The SWNT/ormosil-modified electrodes were characterized with scanning electron microscopy (SEM), Atomic Force microscopy (AFM) and UV-vis spectroscopy. Cyclic voltammetry and amperometry measurements were used to study and optimize the performance of the resulting peroxide biosensor. The effect of pH, enzyme amount, apply potential on the peroxide biosensor has been systemically studied. Experimental results showed that SWNT/ormosil modified provide excellent matrices for the immobilization of HRP and the optimized electrochemical biosensor exhibited long linearity, a low limit of detection, high stability and good reproducibility for the detection of H2O2. The fabricated biosensor had a fast response of H2O2 and excellent linear range of concentration from 5x10-7 to 1x10-4M with the detection limit of 0.3µ M (S/N=3) under the optimum conditions.
Part Ⅲ：A film (CrV-MWCNTs) which contains multi-walled carbon nanotubes (MWCNTs) functionalized with crystal violet (CrV) has been deposited on glassy carbon electrode (GCE). The presence of light at the film decreases the electron transfer resistance. The film also exhibits a promising enhanced electrocatalytic activity towards oxygen reduction in presence of light. The functionalization of MWCNTs with CrV has been confirmed using UV-Visible and FT-IR spectroscopy. The electrocatalytic responses of oxygen at CrV-MWCNTs were measured using cyclic voltammetry (CV) and hydrodynamic experiments (RDE). From electrocatalysis studies, it is obvious that, the reduction current of oxygen is higher at CrV-MWCNTs film in presence of light when compare in the absence of light or only at MWCNTs.

並列關鍵字

Singlewalled carbon nanotubes ； Multiwalled carbon nanotubes ； Methylene green ； Methylene blue ； Crystal violet ； Ormosils ； Horseradish peroxidase ； Hydrogen peroxide ； Nafion

參考文獻

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