本研究利用微機電技術，且使用陽離子選擇性膜(Nafion)替代奈米管道製作出可用於樣品預濃縮的微流體晶片。當施加電場於微流體晶片時，由於陽離子選擇性膜內孔徑的電雙層重疊現象，使得陽離子選擇性膜內形成離子選擇之特性。此特性造成奈米通道內存在陽離子與陰離子的通量差異，導致在微奈米管道介面形成濃度極化之效應，在離子交換膜附近濃度梯度的發生。陽極端可觀察到離子消散區形成，而在離子消散區與電滲流流場交接處有一電場降幅區，利用電場降幅使離子累積，因此在管道中形成一個高濃度的界面，達到濃度預集中之目的。
本論文主旨，在探討陽離子選擇性膜的改質，在傳統陽離子選擇膜(Nafion)內添加氧化石墨烯應用於樣品預濃縮晶片上，藉由氧化石墨烯內自身的官能基，來提高我們預濃縮現象。探討如何提高富集效果的可行性，進而達到最佳化。因此，我們分別討論氧化石墨烯與Nafion的混合比例和不同氧化石墨烯的含量，找出彼此參雜的最佳比例及濃度，再與單純的Nafion材料，進行比較。由實驗結果可發現，我們利用30 V電壓差進行實驗，在直通管道下，利用0.5 wt %氧化石墨烯與Nafion以體積比三比一進行調配，所製造出的離子選擇膜，可聚集螢光在30分鐘裡達到60倍，優於傳統Nafion的40倍。

In this thesis, we utilized the micro-electromechanical technique using Nafion instead of a nanochannel in microfludic chips for use in sample preconcentration. When an electric field is applied to the micro-nano chip, the cation selective membrane (Nafion) has the characteristic of cation and anion flux difference due to the overlapped double layer effect in the nanochannel, which results in the concentration polarization phenomenon at the micro- and nano-interface. The concentration polarization phenomenon causes a concentration gradient to occur near the membrane. On the anodic side, the ion depletion zone can be induced by applying a voltage. The ion accumulation is the result of the difference in electro-migration at the boundary between the depletion zone and electroosmotic flow. Therefore, it creates a high concentration interface in the channel to achieve ion concentration.

The aim of this study was to explore a modified cation selective membrane by adding graphene oxide (GO) to a traditional Nafion membrane used in preconcentration chips. It was found that the GO functional group, enhanced our preconcentration phenomenon. We also discuss how to enhance the feasibility, after which we optimize the preconcentration effect in this modified membrane. To this end, we respectively mix GO and Nafion with different volume ratios and GO content (%) to find the optimal volume ratio and concentrations. Then, we compare GO/Nafion with Nafion alone. Based on the experimental result, we applied a voltage of 30 V in a straight microchannel. In using 0.5 wt % GO to mix with Nafion, the GO volume was three times more than that of the Nafion. These kinds of GO/Nafion ion selectivity membranes can achieve a 60-fold increase in preconcentration factor within 30 min, which is superior Nafion membranes that offer a 40-fold increase.

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