PEDOT薄膜修飾電極對化學及生物感測之電化學應用

PEDOT Composite Electrode for Chemical and Biosensing Applications

陳志瑋(Zhi-Wei Chen)

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(2008年)

摘要

本研究主要分為三部分來討論，第一部份研究以循環伏安法製備 聚3, 4-二氧乙基噻吩 ( PEDOT ) /溴瑞香草酚藍 ( BTB ) 複合薄膜電極。由前文所述，我們將此修飾電極稱之為PEDOT-BTB複合薄膜電極。PEDOT-BTB複合薄膜電極在0.1 M的硫酸溶液下表現出好的可逆對稱的氧化還原波峰在電位0.5 V的位置，形式電位差 (△Ep ) 為75 mV，而只有BTB的修飾薄膜電極表現出較差的氧化還原波峰。高傳導性的PEDOT有著較小的電子能隙使的PEDOT-BTB複合薄膜電極有對稱的氧化還原波峰，我們利用循環伏安法 ( CV ) 、電化學石英晶體微量天平 ( EQCM )、原子力顯微鏡 ( AFM ) 等電化學分析方法來解釋此修飾電極的電化學特性。而我們可以使用電化學石英晶體微量天平 ( EQCM ) 測量複合薄膜在黃金電極上的沉積量。此修飾電極在0.1 M硫酸溶液中有一對好的氧化還原波峰在電位0.5 V附近。此修飾電極表現出的電化學特性包含表面的受限制性和對於pH的依賴性。PEDOT-BTB複合電極被拿來對鉻 ( VI ) 作催化還原反應，其結果顯示PEDOT-BTB複合電極成功的電催化還原鉻 ( VI )。
第二部分在說明擴展生物DNA的電化學效益上已經成功了，電沉積PEDOT在電極表面上結合生物DNA再利用浸泡沉積尼羅(河)藍 ( NB ) 。我們將此修飾電極稱之PEDOT/DNA/NB複合薄膜電極。PEDOT/DNA/NB複合薄膜電極可以顯示出ㄧ對好的氧化還原波峰在電壓-0.35 V的位置。此修飾電極被拿來跟PEDOT/NB修飾薄膜電極和DNA/NB修飾薄膜電極做比較對於表面覆蓋濃度 (Γ ) 以及形式電位差 (△Ep ) 的差異。我們利用循環伏安法 ( CV ) 、原子力顯微鏡 ( AFM ) 、電化學阻抗頻譜儀 ( EIS ) 等電化學分析方法來解釋此修飾電極的電化學特性。此複合薄膜電極表面的受限制性在中性環境 ( pH 7 ) 下，在中性環境下亦可以電催化還原雙氧水 ( H2O2 ) 。並且使用計時安培法 ( Amperometric, I-T curve ) 偵測雙氧水催化反應其反應時間不超過六秒且其偵測極限為1μM。此外我們測試了PEDOT/DNA/NB複合薄膜電極對於細胞色素C ( Cyt c ) 的電催化還原反應，當加入Cyt c到pH7緩衝溶液中，可以觀察到還原波峰電流的增加以及氧化波峰電流的減小，這也指出有間接電極反應。其結果顯示PEDOT/DNA/NB複合薄膜電極成功的電催化還原細胞色素C ( Cyt c )。
第三部分成功的製備出胭脂紅酸 ( CA ) 薄膜修飾電極，胭脂紅酸是一種陰離子蒽醌型食用色素染料，溶於水，無毒，可以利用吸附作用和有機化學物質形成化合物，在酸性介質下我們觀察到蒽醌物質有兩電子氧化還原反應。我們利用不同的浸泡時間製備胭脂紅酸薄膜修飾電極，明顯知道當浸泡30分鐘對胭脂紅酸薄膜修飾電極為最佳。我們使用電化學阻抗儀分析此修飾薄膜電極的電化學性質，在酸性環境下亦可以電催化還原SO32-，濃度範圍為1×10–6 到8×10–3 M，其偵側極限為1×10–6 M。

關鍵字

碘溴百里酚藍 ； 複合電極 ； 鉻(VI)催化還原反應 ； 尼羅(河)藍 ； 雙氧水偵測 ； 計時安培法 ； 細胞色素C電催化還原 ； 胭脂紅酸 ； SO32-偵測 ； 電化學阻抗

並列摘要

Part I：Poly (3, 4-ethylenedioxythiophene) (PEDOT) doped with Bromo Thymol Blue (BTB) composite electrode have been prepared electrochemically by using cyclic voltammetric (CV) technique. Hereafter, above modified electrode called as PEDOT-BTB composite electrode. PEDOT-BTB composite electrode showed well defined reversible symmetric redox peak reversible peak with △Ep 75 mV at around 0.5 V (vs Ag/AgCl) and BTB modified electrode showed ill defined peak in 0.1 M H2SO4 solution. The symmetric peak in PEDOT-BTB composite electrode might be due to small electronic bandgap and its high conductivity of PEDOT. The modified electrode was characterized by using cyclic voltammetry, electrochemical quartz crystal microbalance (EQCM), and atomic force microscopy (AFM). The amount of composite deposited in Au electrode was determined by using EQCM technique. The modified electrode exhibits a pair well defined redox peak in 0.1 M H2SO4 soultion. The modified electrode displayed surface confined and pH dependent electrochemical property. The PEDOT-BTB composite electrode was used to catalyze Cr (VI) reduction.
Part II：Glassy carbon electrode, based on PEDOT-DNA with immobilized N-methylphenazonium or Nile blue were prepared. Herein, above modified electrode called as PEDOT/DNA/NB composite electrode. PEDOT/DNA/NB composite electrode exhibited well defined redox peak at -0.35 V (Ag/AgCl) corresponding to NB. The composite electrode was compared with PEDOT/NB and DNA/NB modified electrode and it was found that enhanced peak current and reduced △Ep. Atomic Force microscopy (AFM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy were used to characterize the PEDOT/DNA/NB composite electrode. The composite electrode was exhibited surface confined redox process in neutral pH. The composite electrode was found that pH dependent. The composite electrode exhibited catalytic property towards reduction of hydrogen peroxide. The composite electrode was utilized to amperometric study and its response towards H2O2 detection was less than 6 s and the detection limit was 1μM. The composite electrode also exhibited catalytic property towards reduction of Cyt c.
Part III：The Carminic acid is an anionic, anthraquinone-based food coloring dye. Since CA is relatively water soluble and nontoxic, it forms a model compound for investigation the recovery of organic chemicals utilizing adsorption techniques. For these dyes, reversible reduction waves are observed for the two-electron reduction of the anthraquinone moiety in acidic medium. Carminic acid modified electrode prepared by different immersion time. Obvious current observed when immersing 30 mts in Carminic acid containing solution. This electrode characterized by EIS and electrode used for electrocatalytic reduction of sulfur oxoanions. The linear range 1×10–6 to 8×10–3 M and detection limit for SO32- is 0.1 ×10–6 M.

並列關鍵字

Polymer ； Bromo Thymol Blue ； composite electrode ； chromium (VI) reduction ； nile blue ； H2O2 detection ； amperometric ； Carminic acid ； SO32- detection ； EIS

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