矽單晶上超微電極陣列之電化學重金屬偵測及其它應用

近年來，我們實驗室開發製作的矽單晶上含銅超微電極陣列 (Cu-LSO)是由低成本、低汙染的方式進行制備，在矽單晶上依照特定方向自組裝生成奈米顆粒規則排列而成的陣列狀結構，並且有許多島狀結構遍佈其中。由於超微電極本身可用於微量分析以及化學反應的動力學分析，對其性質的鑑定及認識有助於提升其應用性，而此超微電極陣列在本論文中主要用以進行水溶液相中的微量元素分析的研究。本實驗中首先利用酸蝕方式將材料表面的銅移去，再以簡單的電化學技術將鉍金屬沉積於材料表面，用以增進電化學重金屬元素分析的表現。本篇論文中使用差式脈波陽極剝除伏安法(DPASV)進行重金屬偵測：先以負電位進行預沉積後再逐次向正電位掃描並將被沉積的重金屬元素氧化脫附。為了有效提升電化學偵測的效果，本篇論文中也做一系列的參數調整，包括脈衝強度、掃描速率、預沉積電位及時間等，以期達到最佳化的電化學偵測效果以優化偵測極限。重金屬偵測實驗中，主要是針對鎘金屬以及鉛金屬還有鋅金屬的標準溶液進行偵測，並且進行混合溶液的電化學反應測試，以模擬在真實樣品中的多種分析物的相互干擾現象。而在本論文中也以化學分析能譜儀 (XPS)以及歐傑影像分析能譜儀 (AES)對樣品的表面進行分析，藉此了解各種元素及其化合物在超微電極陣列表面分佈的情況。最後，本論文也進行偵測器的重複使用 (re-use)實驗，藉此檢驗作為偵測器，其是否可以符合可重複使用的特性，結果呈現出此超微電極陣列在數十次的偵測內訊號仍能維持在一定程度。

關鍵字

超微電極；重金屬偵測；差式脈波陽極剝除伏安法；鉍

並列摘要

The ultramicroelectode arrays (UMEA) called LSO our lab has developed in recent years hold promises for trace analysis and kinetic studies of electron transfer reactions. In the development, we introduce a novel, facile method to fabricate copper-based UMEAs (Cu-LSO) on silicon wafers. It has the advantages of low fabrication cost and of posing no harm to the environment. Plane, island, and extruded structures are present on the Cu-UMEAs surface. Besides, Bi-based UMEAs (Bi-LSO) were fabricated by removing Cu, of Cu-LSO with acid and depositing Bi via cathodic potentiostatic deposition or continuous cyclic sweeping of the potential. Acid etched the island structure of LSO, leaving the extruded structure intact. Bismuth sprouted randomly on the acid-etched LSO surface during the deposition process for both deposition methods. Bi-LSO prepared via either potentiostatic deposition or cyclic sweeping of the potential had the ability to detect the heavy metal ions. In this thesis study, we explored the factors that could enhance the performance of heavy metal detection. In addition, analyzing standard Cd and Pb solutions using differential pulse anodic stripping voltammetry (DPASV) showed that Bi-LSO exhibited higher sensitivity to heavy metal ions than Cu-UMEAs. The detection limit was about 50-100 ppb. X-ray photoelectron spectroscopy (XPS) studies showed that, for re-use of the electrodes, acid etching could remove almost all the metals on the LSO before Bi was deposited again. Auger electron microscopy (AES) and scanning Auger-electron microscopy (SAM) performed the surface images with the element distribution. And the refresh test showed that the LSO could be re-used for at least 20 times.

並列關鍵字

ultramicroelectrode ； heavy metal detection ； differential pulse anodic stripping voltammetry ； bismuth

參考文獻

3. H.Y. Liao, K.J. Lo, C.C. Chang, Nanotech., 2009, 20, 465607

36. H.Y. Liao, K.J. Lo, C.C. Chang, Nanotech., 2009, 20, 465607

28. V. Viswanathan, F.Y. Wang, Nanoscale, 2012,4, 5110-5117

14. X. Wang, U.S. Ozkan, Journal of Physical Chemistry B, 2005, 109, 1882-1890

Chapter I

國際替代計量

矽單晶上超微電極陣列之電化學重金屬偵測及其它應用

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