導電高分子與金屬奈米複合物合成及其在電化學分析的應用

Studies of conducting polymer-metal nanocomposite and polymer composite electrodes for electroanalytical applications

BALAMURUGAN A(A.BALAMURUGAN M.Sc., B. Ed.,)

指導教授 ： 陳生明

國立臺北科技大學/工程學院/工程科技研究所/博士(2009年)

摘要

Poly[3,4-ethylenedioxythiophene-co-(5-amino-2-naphthalenesulfonic acid)] [PEDOT-PANS]的複合薄膜修飾玻璃碳電極是利用電化學方法來做高分子合成和對此複合薄膜修飾電極做研究，我們可以得知此複合薄膜修飾電極的性質是與實驗條件與狀況有很大的關聯性，例如：高分子單體的氧化電位和酸鹼值，而在複合薄膜修飾電極的表面情形，我們則是利用SEM來做觀察與研究，而PEDOT-PANS的複合薄膜修飾電極對多巴胺在醋酸緩衝水溶液(pH 5.0)中的氧化，有很高的電催化活性，其結果也增加了電流的訊號。在線性掃描伏安法的波峰高度也與多巴胺的濃度呈線性關西,其濃度範圍約在2×10-6 到1×10-5 M，偵測極限約為5×10-7 M，也能夠有效的降低抗壞血酸與尿酸的干擾，本研究主要在提供一個簡易的方法在含抗壞血酸與尿酸的溶液當中來對多巴胺做選擇性的偵測。
導電高分子poly (3,4-ethylenedioxythiophene) (PEDOT)摻雜silicomolybdate (SiMo12O404-or SiMo12)利用電化學方法來合成高分子複合薄膜.在強酸溶液0.2 M H2SO4當中此複合薄膜的氧化還原反應有很快速的電子轉移，其複合薄膜修飾電極對bromate的電催化還原有很好的效果以及能成功作為bromate的安培法偵測器且也能利用來對抗壞血酸的氧化做研究。
導電高分子poly (3,4-ethylenedioxythiophene) (PEDOT)摻雜4-Phenyl azo aniline (4-PAA)利用電化學沉積來做修飾薄膜電極，其中把4-PAA當做中間物並利用循環伏安法來做製備，而上述的修飾電極我們稱為4-PAA/PEDOT/GC修飾電極，我們將利用循環伏安法對其電化學特性和氧化還原性質對pH值的影響做研究，我們可以發現此複合薄膜修飾電極是一種與pH值相關的修飾電極，而在伏安圖中我們也可知道此複合薄膜修飾電極在KHP緩衝水溶液中有良好的穩定性，4-PAA/PEDOT/GC電極對NADH (nicotinamide adenine dinucleotide) 的氧化有很好的電催化活性，大約是在400 mV並低於裸電極，在4-PAA/PEDOT/GC修飾電極中，其PEDOT扮演了一個很重要的角色去分離NADH與AA的氧化波峰，此修飾電極對FIA有很穩定的訊號，其偵測極限在生理上的酸鹼值是50 nM。
銀的奈米粒子與poly [3, 4-ethylenedioxythiophene] PEDOT修飾電極也是利用電化學方法來製備，而銀奈米粒子與PEDOT修飾電極是使用簡易的電化方法在“soft conditions”下來製備，即是在低溫度之下，沒有利用強還原劑與穩定劑來製備得到，此複合薄膜修飾電極的表面型態我們則是利用AFM來做觀察，我們可以看到銀的奈米粒子在PEDOT當中是比在裸電極製備的情形之下來得更小顆，從AFM也同時可以得知銀奈米粒子均勻分布在PEDOT當中而其薄膜厚度約為35nm，此複合薄膜修飾電極在沒有酵素或中間物的輔助下對過氧化氫的還原有很好的電催化活性，並有7uM的偵測極限與5s的反應時間。

關鍵字

PEDOT奈米複合物 ； NADH ； 抗壞血酸 ； 多巴胺 ； FIA計時安培法 ； 銀奈米粒子

並列摘要

Poly[3,4-ethylenedioxythiophene-co-(5-amino-2-naphthalenesulfonic acid)] [PEDOT-PANS] film modified glassy carbon electrode was prepared by electrochemical polymerization technique. The properties of modified electrode were studied. It was found that the electrochemical properties of modified electrode were very much dependent on the experimental conditions such as monomer oxidation potential and pH. The modified electrode surface was characterized by scanning electron microscopy (SEM). The PEDOT-PANS film modified electrode shows electrocatalytic activity toward oxidation of dopamine (DA) in acetate buffer solution (pH 5.0) with a marked enhancement of the current. More over, the interferences of ascorbic acid (AA) and uric acid (UA) were studied.
Electrically conducting poly (3,4-ethylenedioxythiophene) (PEDOT) film doped with silicomolybdate (SiMo12O404- or SiMo12) was synthesized by electrochemical polymerization. The synthesized film is capable of fast charge propagation during redox reactions in strong acid medium 0.2 M H2SO4 solution. The modified electrode was used towards reduction of bromate and successfully employed as an amperometric sensor for bromate and also above modified electrode was investigated for ascorbic acid oxidation.
Poly(3,4-ethylenedioxythiophene) (PEDOT) electrode, modified by the electrodeposition of 4-Phenyl azo aniline (4-PAA) in which 4-PAA acts as mediator, was prepared by an cyclic voltammetric procedure. Here after, the above modified electrode denoted as 4-PAA/PEDOT/GC modified electrode. The electrochemical properties and an effect of pH on the redox properties of 4-PAA/PEDOT/GC modified electrode were studied by cyclic voltammetrically and it was found that pH dependent electrode and has surface confined character. 4-PAA/PEDOT/GC electrode exhibits electrocatalytic activity towards the oxidation of NADH (nicotinamide adenine dinucleotide) with an activation overpotential, which is ca 400 mV lower than bare electrode. In the 4-PAA/PEDOT/GC modified electrode, the PEDOT film plays important role to separate oxidation peaks of NADH and ascorbic acid (AA). The modified electrode exhibits stable FIA amperometric response and the detection limit was 50 nM in physiological pH.
Silver nanograins (AgNGs) incorporated poly [3, 4-ethylenedioxythiophene] PEDOT modified electrode was electrochemically prepared. AgNGs incorporated PEDOT modified electrode was carried out by simple electrochemical method under “soft conditions” i.e., at low temperatures and without using strong reducing agent and any stabilizer. Surface morphology of silver nanograins (AgNGs) incorporated poly [3, 4-ethylenedioxythiophene] PEDOT modified electrode was characterized by using AFM and it was found particle size of silver in PEDOT modified electrode smaller than in bare electrode. AgNGs incorporated PEDOT modified electrode exhibited good electrocatalytic activity towards reduction of hydrogen peroxide without an enzyme or mediator immobilized in the electrode. It has shown good amperometric response to hydrogen peroxide (H2O2) with the detection limit of 7uM and with response time of 5s.
The above modified electrodes provide a simple and easy approach to selective determination of dopamine, ascorbic acid, NADH, bromate and hydrogen peroxide by using electrochemical techniques.

並列關鍵字

PEDOT nanocomposite ； NADH ； Ascorbic acid ； Dopamine ； FIA amperometry ； Silver nanoparticles

參考文獻

[101] J. Wang, Analytical Electrochemistry, VCH Publishers (1994).

[1] R. W. Murray, “Chemically Modified Electrodes,” Electroanalytical Chemistry, Vol. 13, A. J. Bard, ed., Marcel Dekker Inc., NY, 1984.

[2] R. P. Buck,“Theory and Principles of Membrane Electrodes,” Chapt. 1, Ion-Selective Electrodes in Analytical Chemistry, Vol. 1, H. Freiser, ed., Plenum Press, NY, 1978.

[3] Τ. Matsue, Μ. Fujihara, Τ.Osa, J. Electrochem. Soc. 126 (1979) 500.

[4] R.W. Murray, Acc. Chem. Res.13 (1980) 135.