Electrochemical determination of thiols at poly(3,4-ethylenedioxythiophene)-modified screen-printed electrodes

[[abstract]]本論文利用電化學的方法在水溶液環境中製備聚(3,4-乙烯二氧吩)(PEDOT)的修飾電極，我們利用LiClO4 為電解質，成功的將PEDOT 修飾在網版印刷電極(SPE)上。我們用SPE/PEDOT 修飾電極在pH 2.0 ~ 12.0 環境下偵測榖胱甘?(Glutathione,GSH)的氧化，發現PEDOT 薄膜在酸性到鹼性環境下偵測GSH 都有很好的催化效果，而在pH 7.0 的環境下催化效果最為明顯。同時我們也利用SPE/PEDOT 修飾電極偵測其他硫醇分子。如： (Cysteine,CySH)、(Homocysteine,HCySH)、(N- Acetyl -L-cysteine,NAC)、(Penicillamine,PSH)等。 本研究使用流動注入分析系統，以提昇偵測的靈敏度及降低偵測極限，偵測榖胱甘? (Glutathione,GSH)、半胱氨酸 (Cysteine,CySH)、高半胱氨酸(Homocysteine,HCySH)、N-乙醯基半胱氨酸 (N- Acetyl -L-cysteine,NAC)、二甲半胱氨酸 (Penicillamine,PSH)，其分別偵測極限可以達到0.024、0.038、0.020、0.023、0.039μM，偵測濃度範圍在0.05μM~ 200μM 之間有良好的線性關係，靈敏度分別為0.031、0.031、0.039、0.046、0.043μA/μM。 另外，我們也利用流動注入分析系統（Flow Injection Analysis, FIA）與 column 管做結合，成功可以將CySH和GSH分離且同時進行偵測。[[abstract]]In this study, we prepared a poly(3,4-ethylenedioxythiophene) (PEDOT) modified electrode by the electropolymerization of 0.01 M 3,4-ethylenedioxythiophene at a screen-printed electrode (SPE) in the presence of 0.1 M LiClO4 and 5 mM hydroxypropyl-β-cyclodexdrine. Many thiol compounds were selected as test analytes. Electrochemical oxidation of glutathione in various pH buffer solutions (pH 2.0 ~12.0) was conducted at the SPE/PEDOT modified electrodes. Cyclic voltammetric studies showed that the SPE/PEDOT modified electrodes possessed great catalytic activity toward glutathione oxidation, and the best catalytic responses occurred in pH 7.0 buffer solution. Flow injection analysis (FIA) coupled amperometric detection was used in order to decrease detection limit. The FIA conditions were examined and the FIA signals were optimized. Linear calibration plots were obtained for 0.05-200 ?μM thiols (glutathione、cysteine、homocysteine、N- Acetyl -L-cysteine、penicillamine) with a slope of 0.031、0.031、0.039、0.046、0.043 μA/μM,respectively. The detection limits (S/N = 3) were 0.024、0.038、0.020、0.023、0.039 μM. In addition, cysteine and glutathione can be separated successfully by column and detected by amperomertry simultaneously.[[note]]碩