聚(3,4-乙烯二氧吩)與離子液體複合修飾電極的製備以及雙酚A分析應用

Preparation of Poly(3,4-ethylenedioxythiophene) and Ionic liquid Composite Film Modified Electrodes for Bisphenol A Determination

汪哲毅(Jhe-Yi Wang)

指導教授 ： 鄭淑華

國立暨南國際大學/科技學院/應用化學系/碩士(2014年)

https://doi.org/10.6837/NCNU.2014.00067

摘要

本研究利用電聚合方式，在水溶液下製備聚(3,4-乙烯二氧吩)(poly-3,4-ehtylene-dioxythiophene ,PEDOT) 修飾網版印刷碳電極(SPCE/PEDOT)，接著將離子液體[BMIM+][Br-]利用旋轉塗佈方法修飾到電極表面，成功製備聚(3,4-乙烯二氧吩)複合修飾電極(SPCE/PEDOT/[BMIM+][Br-])。
在電分析應用上，發現SPCE/PEDOT/[BMIM+][Br-]具有氧化雙酚A的效果，氧化電位為0.61V ，和bare SPCE相比，修飾電極偵測雙酚A的氧化電流值增加了15倍，推測PEDOT和離子液體具有良好的導電性，並能促進電子轉移速率，此外，在0.20V出現一對氧化還原對推測為雙酚A的聚合產物，導致電極被毒化的原因。
我們利用循環伏安法，在不同pH值環境下觀察雙酚A的氧化，發現在pH 8環境下其氧化電流值為最大，在pH > 9環境下，由於雙酚A解離(pKa=9.73)使得電極間之吸引力減少，造成電流值下降。為了改善毒化現象，我們在SPCE/PEDOT電極表面修飾上離子液體[BMIM+][Br-]，離子液體本身具有抗毒化的效果，SPCE/PEDOT
/[BMIM+][Br-]在經CV掃完一圈並經過清洗，電流值仍相當穩定，10圈平均電位大約都在0.61 V，可看出經由二次水清洗過後，SPCE/PEDOT/[BMIM+][Br-]第二圈可以藉由沖洗穩定電流值，Br-離子減緩毒化效果為最佳，因此選用[BMIM+][Br-]離子液體，來進行本次研究。並利用FIA方法來進行定量的工作，線性範圍為0.1-20 μM，偵測極限0.025 μM (S/N = 3)，此修飾電極可以應用於含有雙酚A真實樣品的定量工作，獲得不錯的回收率。

關鍵字

電化學 ； 聚(3,4-乙烯二氧吩) ； 離子液體 ； 雙酚A

並列摘要

In the study, we modified a thin layer of poly (3,4-ehtylenedioxythiophene) on SPCE (screen-printed carbon electrode) by electrochemical methods, and then ionic liquid ([BMIM+][Br-]) was fabricated onto SPCE/PEDOT by spin coating. The obtained modified electrodes were further examined as electrochemical sensors for bisphenol A (BPA). Cyclic voltammetric studies showed that the SPCE/PEDOT/[BMIM+][Br-] showed enhanced oxidation current over 15 times compared to bare SPCE. In addition, a new redox couple at 0.20 V was observed following the second potential scan. The peak current of BPA decreased during the second cyclic voltammetry scanning. This is clearly evidence that the for the formation of an electroactive product of BPA on the electrode surface. The oxidized product could decrease oxidation current because of electrode poison, and modification of a layer of ionic liquid can improve the electrode activity. We used flow-injection analytical methods for the determination of BPA. A linear calibration plot was obtained for 0.1-20 μM BPA, and a sensitivity of 0.2595 μA/ μM was obtained. The detection limit was 0.025 μM (S/N = 3). The proposed SPCE/PEDOT/[BMIM+][Br-] was successfully applied to
determine BPA in real sample with good recovery.

並列關鍵字

Electrochemical ； Poly (3,4-ethylenedioxythiophene) ； Ionic liquid ； Bisphenol A

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