奈米碳管修飾氧化銦錫電極對多巴胺電流之影響

Abstract

氧化銦錫玻璃(ITO)因其具有良好的導電性與光的通透性，是個極為廣泛使用的光電材料。在一些微晶片電泳的研究中，ITO是一個新型的晶片基材。然而，若把氧化銦錫拿來作電化學的偵測器時，會發現他的電化學活性比起其他的材料要來得低很多。為了增加電化學活性，我們勢必要在這類型電極表面作一些修飾。 奈米碳管的一些特殊的電子特性，及化學與機械穩定性，讓ITO在電化學與生物化學感測器的研究上有著很大的的吸引力。高導電度、高比表面積，這些性質讓奈米碳管在掃描循環伏安法時能夠增加催化電流，有時能夠些微的減少施加的催化電壓。本實驗中，使用離子型高分子Nafion(R)來幫助固定多壁奈米碳管在電極表面。儘管Nafion(R)可能會造成催化電流的減少，可是和奈米碳管所帶來的增益相比，這種減少是在可容許的範圍內。 在電極的表面，旋轉塗佈了一層無序排列的奈米碳管薄膜，而碳管表面的官能基，可以讓電極對特定分析物更俱選擇性。當使用這種電極偵測兒茶酚與多巴胺時，氧化電流分別增加100倍與20倍，而還原電流則增加分別增加110倍與1000倍。

Tin-Doped indium oxide (ITO) film is a good photoelectric material for its good conductivity and photo penetrability. It is a new type of microchip substrate in some research. However, the electro-catalytic activity of ITO is relative low versus most kind of detector. In order to increase the electro-catalytic activity, modification of surface of ITO glass was needed. The electronic property, chemical and mechanical stability of carbon nanotubes (CNTs) make them attractive for electrochemical and biochemical sensor. In addition, high surface area, high conductivity of CNTs increases the catalytic current and sometimes decreases catalytic voltage of cyclic voltammetry. Ionic polymer would help for binding nanotubes on ITO electrode under the allowable of catalytic current lost. In this research, multi-walled carbon nanotubes (MWNTs)/Nafion(R) composite films were made. The surface of ITO glass was modified with such nano composite films for the measurement of pyrocatechol. The functional groups beside CNTs make them more attractive and selective under electrocatalysis. We use CNTs matrix as none-oriented films spin-coated on ITO electrode for specific analyte. The oxidation current of modified-electrode measuring with Catechol and Dopamine is 100 fold and 20 fold larger than bare ITO respective. The reduction current is 100 fold and 1000 fold lager than bare ITO respective.