Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/14967
標題: 利用全氟磺酸聚合物修飾電極偵測尿酸、多巴胺及巴拉松之研究
A Selective Voltammetric Method for Uric Acid Detection Using Preanodized Perfluorosulfonated Ionomer-Coated Glassy Carbon Electrodes
作者: 周家禎
Jou, Jia-Jen
關鍵字: Voltammetric;全氟磺酸聚合物;Uric Acid;Preanodized;Perfluorosulfonated;巴拉松;尿酸;多巴胺
出版社: 化學系
摘要: 
在許多電化學分析的文獻中,許多學者先在光滑碳電極表面施以一前
處理步驟後再對分析物加以偵測,如此可改變電極表面的電化學行為並增
加電極的靈敏度。本研究第一部份即是以一預氧化(preanodization)之前
處理步驟偵測尿酸。首先在光滑碳電極表面修飾一層陽離子交換薄膜(
Nafion),然後將電極置於緩衝溶液中以+2.0 V預氧化90秒後,配合方波
剝除伏安法進行偵測,發現靈敏度的提高是因為電極預氧化之後在電極表
面產生的羰基(carbonyl group,>C=O)與尿酸產生氫鍵,進而觀察到明顯
的吸附現象,雖僅預濃縮10秒,偵測極限卻可達到10 nM,又溶液的pH值
為5,剛好介於尿酸與維他命C的pKa之間,此時由於兩者帶電性的不同,
加上Nafion的修飾使得此分析方法可成功的避免50倍維他命C之干擾,因
此對於真實尿液樣品的分析,皆可得到很好的回收率。 第二部份亦是
利用偵測尿酸之方法來偵測多巴胺,先將Nafion修飾電極置於緩衝溶液中
以+2.0 V預氧化15秒後,由實驗結果發現多巴胺在電極表面的行為和尿酸
完全一樣,故推斷也是因氫鍵的形成而有吸附的現象。在偵測方面,以
open circuit方式預濃縮30秒,其偵測極限為4.7 nM,同時對於1000倍的
維他命C,干擾情形亦很小。 第三部份則是利用Nafion修飾電極直接
偵測溶液中的巴拉松,利用其電化學特性,以-0.6 V預濃縮40秒後,將在
電極表面的巴拉松還原成一具有可逆性之物種,由於方波掃描對可逆性之
物種會有較高的靈敏度,因此立即以方波剝除伏安法進行掃描。此電極的
再現性極佳(CV = 1.9 %),偵測極限則為50 nM。

The electrochemically preanodized Nafion-coated glassy carbon
electrodes(NCGCEs) were used for the selective determination of
uric acid (UA) by square-wave voltammetry. The major
interference of ascorbic acid (AA) is overcome due to the
distinct ability of the preanodized NCGCE to yield its best
performance around pH 5. At pH 5, AA exists in the anionic form
whileUA is in the cationic form since the pKa''s are 5.4 and 4.1
at 25 ℃ for UAand AA, respectively. Consequently, the Nafion
film repels the negativelycharged AA and the selective sensing
of UA can be achieved. Moreover, theanodized surface has an
high affinity towards the UA through hydrogen bonding. Thus,
the combination of the preanodization and the Nafion film
modification works excellently in the determination of UA.
Under optimized conditions,the detection limit for UA has been
improved to 10 nM (S/N = 3). The practical analytical is
demonstrated by the measurement of UA in human urine without
anypreliminary treatment.
URI: http://hdl.handle.net/11455/14967
Appears in Collections:化學系所

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