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標題: 利用化學修飾電極偵測銅、亞硝酸鹽及一氧化氮之研究
The Determination of Copper(II) Nitrite and Nitric Oxide Using Chemically Modified Electrode
作者: 王樹範 論文開放日期:20050101
Wang, Hsu-Fann
關鍵字: 化學修飾電極;CME;粘粒;全氟磺酸聚合物;一氧化氮;亞硝酸鹽;nontronite;Nafion
出版社: 化學系
在偵測銅離子部分,是將銅離子置於 ammonia solution中,使其成為 Cu(NH3)42+ 錯合物,利用硬酸硬鹼理論使其與粘粒中高氧化態的鐵離子之間產生吸附作用而沈積於電極表面,再配合方波剝除伏安法對銅離子進行定量,在pH 10之 ammonia solution中,配合實驗最佳化參數下,濃度校正曲線線性範圍為 20 ppb ~ 4 ppm,偵測極限為1.87 ppb(S/N = 3)。
在第二部分的實驗中,先對全氟磺酸聚合物鉛釕黃綠石氧化物修飾電極之特性作一詳盡之探討,並將光滑碳電極與全氟磺酸聚合物修飾電極作電化學性質之比較,其後運用亞硝酸鹽在酸性溶液中生成一氧化氮之反應,使用催化物電極在含有亞硝酸鹽之 pH 1.65的 0.1 M KCl 溶液中,發現催化物電極對於亞硝酸鹽的氧化以及一氧化氮還原有極佳之催化效果。
定量分析方面,使用催化物電極結合流動注入分析法偵測亞硝酸鹽,於 pH 5.4之0.1 M KCl 流動相中其濃度線性範圍為 0.1 μM ~ 100 μM,偵測極限為 4.8 nM(S/N = 3)。而在一氧化氮部分,在 pH 1.65 之0.1 M KCl 的流動相中,其濃度線性範圍為 0.8 μM ~ 63.3 μM,偵測極限為 15.6 nM(S/N = 3)。

There are two parts in this thesis, according to different chemically modified electrode. Part 1 were "A Nontronite Clay/Cellulose Acetate Modified Film Electrode for the Trace Detection of Copper in Water", and part 2 were" Mechanistic Study of NO2- Oxidation and NO Reduction on the Nafion/Lead-Ruthenium Oxide Pyrochlore Chemically Modified Electrode".
In part 1, The behavior of nontronite clay modified glassy carbon (NGC) electrode towards Cu2+ in various solution pH has studied. The NGC electrode exhibits excellent electrocatalytic activity for Cu2+ reduction. However, the regeneration of the NGC is poor and therefore, a permselective membrane cellulose acetate is used as the immobiliser for the nontronite clay on GC (NCAGC) electrode. The NCAGC electrode exhibits higher regeneration compared to NGC electrode. NCAGC electrode is applied for the determination of trace level Cu2+ in aqueous solution. A detection limit of 20 ppb was achieved with the preconcentration time of 2 minutes ( in pH 10 ammonia solution ) , as determined for a signal-to-noise ratio of 3, and linear calibration plot was obtained in the 20 ppb to 4000 ppb. The practical utility of the electrode was assessed for real sample application.
In part 2, The Nafion/lead-ruthenium oxide pyrochlore modified electrode (NCME) was found very efficient for both the NO2- oxidation and NO reduction reaction. Both the cyclic voltammetry and ac-impedance techniques were adopted to probe the mechanistic aspects of the NCME towards these reactions. The obtained current function for NO2- oxidation on the NCME was around 3 times higher than that at a GCE. The ac-impedance results showed a much lower Faradic charge transfer resistance on the NCME than either a GCE or Nafion/GCE for both the oxidation and reduction processes. Meanwhile, both the exchange current density and intrinsic heterogeneous rate constant were calculated and the mechanism was systematically analyzed. These catalytic reactions were explained in terms of redox mediations through higher Ru(VI)/Ru(IV) and lower Ru(III)/Ru(II) pathways.
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