三嗪衍生物-銅複合物之離子液體碳糊電極的製備及過氧化氫偵測上的應用

過氧化氫(H2O2)被廣泛的應用在工業科技上例如紙張的漂白劑、燃料的推進劑等…。此外，過氧化氫是許多氧化酶反應後的副產物。在體內若干酵素反應亦可能產生H2O2。過氧化氫是一種強氧化劑在人體內會氧化正常細胞、蛋白質或DNA導致細胞凋亡，因此對生物體來說是一種毒性物質。綜合上述原因過氧化氫在生物體及環境的偵測是重要且必需。比較常見的電化學偵測方法是利用貴金屬或酵素電極進行電催化，但銀、白金這類貴金屬的價格高昂而酵素電極在極端環境下像是高溫、高濃度離子、強酸或強鹼條件下容易失去活性。因此有部分研究是利用非貴金屬如鐵、鈷、鎳或銅等金屬配合有機或無機配位分子製備出仿酵素電極以進行過氧化氫的電催化反應，進而達到降低成本和環境穩定性之目的。本實驗用一簡單且快速的方法製備離子液體碳糊電極，並進一步利用合成出的新有機配位化合物:吡啶修飾之三聚氰胺化合物與銅二價進行配位形成一種仿酵素之銅金屬錯合物電極。這種仿酵素化合物銅錯合物電極對於電化學催化過氧化氫還原有很好的效率，對於以混合含銅錯合物粉末為修飾法之複合電極，其偵測極限為10 uM，線性範圍在20 uM~1700 uM間。以混合離子液體溶解有機分子銅錯合物為修飾法之複合電極方面，使用氯化銅時，其偵測極限為0.25 uM，線性範圍介於0.5~360 uM之間，而使用硫酸銅時其則僅為1 uM，線性範圍在 6~360 uM間。但由於銅金屬對於氧氣也有很好的催化效果，因此在過氧化氫催化實驗時必須在除氧的條件下進行方得到較佳的結果。此外，本實驗亦發現當銅二價來源為硫酸銅，所製備之碳糊電極受尿酸之干擾相當嚴重。

關鍵字

離子液體；電化學；過氧化氫

並列摘要

Hydrogen peroxide (H2O2) is a strong oxidant widely used in industry such as paper bleaching, propellant and etc. Moreover, H2O2 is a product of various biological reactions of oxidases and it is toxic to cells due to its oxidizing ability on proteins and DNA. Therefore, it is important and necessary to detect H2O2 in environment or body fluids. There were many studies of analytical H2O2 sensing where noble metals or enzymes were used as the electrocatalysts. However, noble metals such as Ag or Pt are expensive and enzymes lose activity in critical environments such as high temperature, strong acids or bases, and high concentrations of ionic species. Therefore, some studies were focused on the preparation of cheap and reliable enzyme mimics such as iron, copper, nickel or cobalt complexes for H2O2 detection. In this study, we used a simple and convenient method to prepare ionic liquid carbon paste electrode. We also synthesised a new organic ligand: pyridine functionalized melamine, which coordinated copper as an enzyme mimic that is employed for the preparation of enzymeless H2O2 electrode. This enzyme mimic electrode shows good electrocatalytic efficiency toward H2O2 reduction. The steady-state reduction current linearly depends on the concentration of hydrogen peroxide from 20 μM to 1700 μM with the detection limit of 10 μM for copper complex powder modified electrode. For the modified electrodes in with copper complexs were directly dissolved in ionic liquid, a linearity was observed in the range from 0.5 μM to 360 μM with the detection limit of 0.25 μM for using CuCl2 as the copper source. A linearity was observed in the range from 6 μM to 860 μM with the detection limit of 1 μM for using CuSO4. Unfortunately, this enzyme mimic also shows good electrocatalytic activity to oxygen reduction so that the catalysis of hydrogen peroxide should take place in saturated Ar electrolyte. Moreover, it was found the uric acid (UA) produced a serious interfering effect on H2O2 detection if CuSO4 is used as the copper source of the copper complex.