- 學位論文
電化學式之鏡像選擇L與D谷胺酸之感測器
Molecularly Imprinted Electrochemical Sensor able to Enantioselectively Recognize L and D- glutamate
摘要
本文研究具有鏡像辨識的L和D-谷胺酸分子功能之分子模板電化學式感測器，以砒咯與目標分子在Pt電極上進行電聚合，利用多電位手段(Multi-Potential Steps) 在0V和5V(vs. Ag/AgCl)分別持續1sec和2sec總共進行20循環，來探討鏡像選擇性，評估他們的感測表現。對於在10mM之L與D谷胺酸待測液濃度進行檢測，擁有高鏡像選擇性分別為L/D = 11.41和D/L=10.90。本文並針對分子模板的功能包括:目標物萃取時間、目標物萃取電壓、薄膜前處理電壓與前處理時間…等進行探討；另一方面利用一系列的分析技術包括: AC Impedance、chronoamperometry、FTIR和SEM來鑑定薄膜之特性。另外；研究發現熱效應對谷胺酸分子模板感測薄膜具有明顯的影響，隨著時間感測器的(L/D)鏡像選擇性將會明顯下降從11.4到1.2，暴露在空氣中當置放時間從初始狀態到90分鐘(在薄膜中的目標分子萃取後)，無論如何，此(L/D)鏡像選擇性可以被維持在低溫的液態氮蒸氣環境中。最後，本研究提出熱效應與施加正電壓對聚砒咯分子模板作用影響的辨識機制。
並列摘要
Enantioselective molecularly imprinted electrochemical sensors for the recognition of D and L glutamate were prepared by the electro-polymerization of pyrrole together with the target molecules on Pt electrodes. Enantioselectivities were investigated using multi-potential steps to evaluate sensing performances. Using this procedure high enantioselectivities were found for each imprinted film. The individual selectivities for L and D- glutamate, on their respective imprinted films, were estimated to be L/D=11.4/1 and D/L=10.9/1, these values being determined by applying potential steps at 0V and 5V(vs. Ag/AgCl) held for 1sec and 2sec, respectively, for a total of 20 cycles with the two enantiomers being present at the same concentration (10mM). Several factors affecting rebinding, e.g. the extraction time, the applied potential used for extraction, film pretreatment potential and pretreatment time, were investigated to achieve optimum recognition ability. Techniques including: AC impedences, chronoamperometry, FTIR, SEM, were used to characterize the films’ properties. The recognition ability of the glutamate sensor was found to be significantly affected by Thermal effect, with enantioselectivity rapidly decreasing from 11.4 to 1.2, i.e. from the initial time of exposure to air to 90min after the extraction of the target molecule from the film. However, the enantioselectivity could be maintained at a lower temperature in liquid nitrogen vapor environment. Finally, a recognition mechanism based on the interaction of the polypyrrole film with the template molecule, under the joint influences of applied positive potential and Thermal effect, is proposed in this study.