(2-膦酸乙基)-4,4’-氯砒碇與5-N,N-甲基胺基-1-磺醯氯電極的製作與應用

Abstract

實驗結果顯示：部分發光與敏光物質，如5-N,N-甲基胺基-1-磺醯氯 (Dansyl chloride)與 4,4`-砒碇衍生物(Viologen)對環境中酸鹼值變化極為敏感，並可經由化學修飾法，將之固定修飾於TiO2或SnO2奈米微粒表面成為化學修飾電極。根據此一持性，我們可藉由反射式螢光與吸收光譜分析法環境中氫離子濃度變化進行分析，進而對生化重要物質，如葡萄糖，進行濃度檢測。若對Viologen 修飾電極施加適當電壓時，此電極會顯現藍色色澤，在600 nm處的吸收度會隨溶液pH值降低而呈線性成長。根據此一特性，我們可進一步將該電極修飾成葡萄糖偵測電極，對溶液中葡萄糖進行濃度分析。Dansyl chloride 修飾電極也具有類似應用潛力，其螢光強度會隨環境中的酸鹼值增加而呈線性成長，線性範圍為:2<pH<6。由於此一特性， Dansyl chloride 修飾電極亦具有檢測葡萄糖的應用潛力。另外，我們也利用其他電化學方法如計時電位法(chronopotentiometry)和電化學交流阻抗分析法(Electrochemical Impedance Spectroscopy, 簡稱EIS)對其中的物理現象作進一步的探討。 此外，我們也發現Dansyl chloride修飾電極對Fe3+離子的存在極為敏感，但對Fe2+則幾乎不產生訊號。因此，本電極具有作為Fe3+偵測器的潛力。

In view of the unique spectral and electrochemical properties inherent in viologen and dansyl chloride, we prepared viologen- and dansyl chloride-modified electrodes for chemical analysis. With the assistance of SnO2- and TiO2- nano particles, viologen can be anchored on the surface of indium-tin-oxide conductive glass. The resulting electrodes show color changes on their surface as biased with proper cathodic potentials. In-situ absorption spectral analysis shows that the absorbance of the 600-nm band increases in a linear manner with a decrease in pH, leading to a further possibility for the detection of glucose at ambient condition after the electrodes are further modified with glucose oxidase. Dansyl chloride-modified electrode also reveals a potential in chemical analysis. In aprotic solution systems, the anchored dansyl group emits light as exposed to UV irradiation. The emitted light increases in intensity with a decrease in [H+]. A linear calibration curve between pH 2 and 6 thus results. Although this unique property is sacrificed in aqueous solutions, the electrode turns out to show a remarkable response to Fe3+, which is more significant than to Fe2+. In view of this difference, the dansyl chloride-modified electrode can be used to distinguish Fe3+ from Fe2+ in aqueous solutions. Fiber optics and electrochemical impedance support this potential.