自組裝修飾網版印刷金電極電催化氧化抗壞血酸及多巴胺之研究

本論文於網版印刷金電極上修飾一層自組裝單層薄膜，成功製備AuSPE-AET修飾電極，並以此修飾電極來電催化氧化抗壞血酸(AA)及多巴胺(DA)。 AA為人體中的必須維生素，也是人體中重要的抗氧化劑，當人體缺乏時會得到敗血症，嚴重時甚至死亡。DA則為人大腦所分泌的一種神經傳導物質，當缺乏時手腳會不自主的顫抖，俗稱帕金森氏症。AA及DA在人體中為不可缺少的物質，故對AA及DA的偵測便顯得格外對重要。首先，我們以電化學方法求出自組裝薄膜的表面覆蓋率(Γ)及表面電容(Cdl)，再利用ESCA、AFM對AuSPE-AET電極進行表面鑑定。而後，再以循環伏安法(CV)來探討於不同pH環境下AA與DA電流及電位的變化，並探討電極與偵測物之間的作用力。以差式脈衝伏安法(DPV)偵測不同濃度下的AA與DA混合溶液，求出其偵測極限都為0.7 μM，AA與DA的線性範圍分別為1~1000 μM、2~1000 μM，斜率分別為0.1603 μA/μM、0.1583 μA/μM。以流動注入分析系統(FIA)偵測不同濃度下之AA，求出其偵測極限為6.7×10-4 μM，線性範圍為0.01~100 μM，斜率為0.03719 μA/μM。而在電極穩定性方面，我們以AuSPE-AET修飾電極利用FIA偵測50 μM AA連續針測100次，得其RSD% = 1.647，證明此修飾電極相當穩定。其後再以FIA偵測AA的真實樣品，回覆率為94%~102.5%。

關鍵字

自組裝單層薄膜；修飾電極；抗壞血酸；多巴胺；電催化氧化

並列摘要

A monolayer of 2-aminoethanethiol (AET) was modified on a screen-print gold electrode through self-assembly procedure to form AuSPE-AET SAM modified electrode. The modified electrode was confirmed by atomic force microscope (AFM) and electron spectroscopy for chemical analysis (ESCA). The modified electrode was characterized by cyclic voltammetry (CV). The obtained surface coverage (ΓSAM) and double-layer capacitance (Cdl) of the AuSPE-AET SAM were 3.65×10-10 mol/cm2 and 64.38 μF/cm2, respectively. The AuSPE-AET SAM modified electrode was used for the simultaneous determination of dopamine (DA) and ascorbic acid (AA) using differential pulse voltammetry (DPV) in pH7 PBS. A linear calibration plot of AA and DA were 1-1000 μM and 2-1000 μM with the slope of 0.1603 and 0.583 μA/μM, respectively. The detection limit were 0.7 μM. The determination of AA was performed at 0.2 V in a flow injection analysis system with pH 7 PBS as a carrier solution. A linear calibration plot was obtained for 0.01-100 μM AA with the slope of 0.03719 μA/μM. The detection limit was 6.7×10-4 μM. The recovery of AA from the real sample were 94%-102.5%.