電化學沉積修飾電極於電化學感測器之應用

Modified Electrodes via Electrodeposition for Electrochemical Sensors

連健宏(Chien-Hung Lien)

指導教授 ： 胡啟章 ； 汪上曉

國立清華大學/工學院/化學工程學系/博士(2013年)

摘要

由於日益嚴重的環境污染和健康照護問題，本研究致力於發展重金屬感測器及非酵素型-雙材料葡萄糖感測器.
首先,在重金屬離子感測器部分，主要著眼於篩選出影響Sn2+靈敏度的鉍薄膜電極關鍵因素。由實驗結果發現，鉍薄膜電極的最佳成晶面向比例(preferred orientation ratio)是主要關鍵因素，但是當最佳成晶面向比例高於0.11時，晶粒尺寸(grain size)大小和最佳成晶面向比例的協同作用(synergistic effect)，讓Sn2+的偵測能力提升。根據此結果，由部分因素實驗設計，我們找出影響最佳成晶面向比例的因素為溶液的pH值和溫度。因此，我們可以控制最佳成晶面向比例由0.09至1.09，並建立最佳成晶面向比例和偵測Sn2+感測能力的關係。
在重金屬離子感測器得第二部分，乃致力於開發氟烯磺酸聚合物(Nafion)修飾石墨烯/奈米碳管及金屬Bi的網版印刷複合電極(簡寫為：Nafion-G/CNT-BiSPE)，並將此電極用於微量的鉛離子偵測。結果發現，Nafion-G/CNT-BiSPE複合電極對於Pb2+的偵測，其電流應答(current response)遠大於其他單一成分之Bi電極。由部分因素實驗設計結果發現，對於Nafion-G/CNT-BiSPE複合電極，影響Pb2 +的偵測的主要因素影響為分析溶液的和Nafion濃度。由此結果，進一步進行陡升實驗，發現在pH值4.75及Nafion濃度0.3%時，偵測1ppm Pb2+的電流可由0.65uA上升至1.03uA。最後，我們使用此複合電極與其他電極在最佳偵測條件下相比較，發現複合電極對於 1ppm Pb2+的偵測，有最佳的偵測電流。
在最後一章節，我們介紹一種新穎的非酵素葡萄糖感測器，此感測器經由使用電沉積方式製備(Ni-Co)(OH)2複合材料於網版印刷碳電極上。研究結果顯示，相較於Ni(OH)2 和Co(OH)2 ，(Ni-Co)(OH)2有明顯的葡萄糖催化行為及較低的氧化電位，此特性歸因於Ni離子和Co離子的原子級混合。在定電位安培法檢測下，可得校準曲線(calibration curve)線性範圍為0 - 3.7mM，靈敏度為122.45 uA mM−1 cm−2，相關係數為0.989。此外， 25uM的抗壞血酸(Ascorbic acid)，尿酸(Uric acid)和多巴胺 (Dopamine) 的干擾測試結果顯示：其干擾百分比為10.76％，14.29％和1.41％，(相較於0.2mM葡萄糖的電流應答)。因此，由以上實驗結果得知本實驗室所開發之非酵素型葡萄糖感測器複合材料，擁有較明顯的葡萄糖催化行為，較低的氧化電位及較大校準曲線範圍。

關鍵字

鉍薄膜電極 ； 電鍍 ； 複合電極 ； 重金屬感測器 ； 非酵素型葡萄糖感測器

並列摘要

The study aims at the development of the heavy metal ion sensors and the non-enzymatic glucose sensor consisting of binary materials due to the growing concerns about the environmental pollution and the health care issue, respectively.
In the first part of the study for heavy metal ion sensors, we developed the bismuth film electrodes (BFEs) for the detection of Sn2+. The preferred orientation ratio (f) of the deposited bismuth was found to be a key factor determining the Sn2+-sensing ability of BFEs. Especially when f is above 0.11, the synergistic effect from the grain size and the f value on the sensing ability for Sn2+ can be observed. Since the fractional factorial design (FFD) of experiments indicate that the deposition pH value and the temperature affect the f of the deposited bismuth, the f was controlled from 0.09 to 1.09 by adjusting these two factors to establish the relationship between the preferred orientation of the deposited bismuth and the sensing ability for Sn2+.
The second heavy metal ion sensor utilized Nafion-modified (graphene/carbon nanotube) composite to deposit with Bi on the screen printed electrodes (SPEs) for detecting trace amount of Pb2+. The preliminary test shows that the Pb2+-sensing ability for Nafion-(G/CNT)-BiSPE was 50-times higher than that of BiSPE. The FFD study revealed that the key factors determining the sensing ability are the deposition pH value and the concentration of Nafion. The steepest ascent pathway (SAP) study further established that the highest sensing ability for Pb2+ can be achieved when utilizing 0.3% Nafion and the stripping buffer solution with the pH equals to 4.75. Finally, the sensitivity and the sensing current obtained under the optimal conditions for SPE, Bi/SPE, Bi/Nafion/SPE, Bi/G-CNT/SPE, and Bi/Nafion/G-CNT/SPE were compared by the results from sqaure wave anodic stripping voltammetry (SWASV).
In the last part, we introduced a novel non-enzymatic glucose sensor via the cathodic deposition of nickel-cobalt hydroxide (denoted as (Ni-Co)(OH)2) on the screen-printed carbon electrodes (SPCEs). Due to the atomic-scale mixing of Ni and Co ions, (Ni-Co)(OH)2 demonstrates the more significant signal and the less positive detecting potential for glucose oxidation compared with Co(OH)2 and Ni(OH)2, respectively. The detection sensitivity for glucose is 122.45 uA mM−1 cm−2 (R2 = 0.989) in the linear detection range up to 3700 uM. In addition, low interference responses from 25 uM ascobic acid (AA), uric acid (UA), and dopamine (DA) were obtained, which were 10.76 %, 14.29 %, and 1.41 % of the detection signal from 0.2 mM glucose, respectively. Consequetly, the non-enzymatic glucose sensor exhibits the low detecting potential, the wide linear detection range, and the high signal-to-noise ratio.

並列關鍵字

Bismuth film electrode (BFE) ； Electrodeposition ； Composite electrode ； Heavy-metal sensor ； Nonenzymatic glucose sensor

參考文獻

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