| Abstract: | 本研究以開發利用電化學方法偵測的線上體外經皮吸收系統為目標。研究重點在於電化學分析關鍵元件—電極的製作與效能分析。由於碳電極材料成本較白金電極低，因此本實驗選擇碳電極為主要的評估對象。
實驗包括比較電極中添加不同量之導電碳(0%、5%和10%)對電極活性的影響，利用電化學阻抗頻譜法(Electrochemical Impedance Spectroscopy,EIS)進行電極特性的分析，使用循環伏安法(Cyclic Voltammetry,CV)偵測不同濃度的赤血鹽和化粧品中常用之活性成份—維生素C及其衍生物，觀察分析電極的響應並探討不同濃度的支持電解質(Supporting electrolyte)對響應電流的影響。
實驗研究結果發現，實驗中製作之碳電極，利用電化學阻抗頻譜法分析得到的極化電阻與電容等電極特性參數有相當好的再現性，顯示製作之碳電極具有相當的穩定性。而循環伏安法分析的結果也顯示在不同濃度的赤血鹽溶液中此電極對於氧化還原反應的響應也有相當一致的穩定度與再現性。至於分析化粧品中常用之活性成分—維生素C及其衍生物時發現，維生素C、維生素C磷酸鎂鹽及維生素C葡萄糖苷的濃度在5.0x10-2~1.0x10-4M範圍時，其濃度與電流響應之線性相關係數均可達到0.9988以上，同時維生素C、維生素C磷酸鎂鹽及維生素C葡萄糖苷三者之分析中以分析維生素C具有最高的靈敏度，維生素C葡萄糖苷之分析次之，分析維生素C磷酸鎂鹽的靈敏度最低。
綜合上述的結果，利用此研究所製備的碳電極具有相當的穩定性且對於氧化還原反應的響應也有相當一致的穩定度與再現性。只要分析其對分析物的靈敏度與線性響應關係就可建立此電極應用在活性成份偵測時的適用範圍，因此應用此電極建立電化學線上體外經皮吸收系統應有不錯的發展潛力。
The ultimate purpose of this research is to develop a on-line electrochemical analysis system used for in-situ transdermal absorption studied for cosmetics. The manufacturing and performance analysis of electrode which is the key component in electrochemical analysis are the main scope in this study. Compared to platinum electrode, the cost of materials used for fabricating carbon electrode is much lower. Therefore, this study is focused on the manufacturing process and performance analysis of carbon electrode.
The effect of conductive carbon content on the activity of electrode was studied. Electrochemical Impedance Spectroscopy(EIS) was used to characterize the electrode. Cyclic Voltammetry(CV) was used to analysis the response of the electrode to K3[Fe(CN)6] and vitamin C and its derivatives which are the common active ingredient of in cosmetics. The effect of supporting electrolyte’s concentration on response current was also studied.
The polarization resistance and capacity of the carbon electrode obtained from electrochemical impedance analysis show good reproducibility. The response of self-made carbon electrode to K3[Fe(CN)6] shows well redox behavior and the responses to ascorbic acid, magnesium ascorbyl phosphate and ascorbyl glucoside show competent linear relation to the concentration of the analyte in the range of 5.0x10-2~1.0x10-4 M with correlation coefficient higher than 0.9988. Furthermore, the response of carbon electrode to ascorbic acid has the highest sensitivity than it to ascorbyl glucoside and the response to magnesium ascorbyl phosphate got the lowest sensitivity among these three vitamin C related substances.
In summary, the self-made carbon electrode in this study shows good stability and competent reproducible response to analyte. The applicable concentration range for active ingredient in cosmetics can be established by analyzing the linear relation and sensitivity of the response to the analyte. It is promising that there are great potential for the utilization of this electrode in the developing of on-line electrochemical in-situ transdermal absorption analysis system.
The test and research result found the carbon electrode of manufacture, make use of the Electrochemical Impedance Spectroscopy method to get characteristic parameters, such as...etc, representability the carbon electrode of manufacture have fairly good and stability. And analysis result of Cyclic Voltammetry method have rather consistent and stability at different contained respondence of redox.As for analyze the often used active ingredient - vitamin C and its derivatives, we found concentrations of within the scope of, its respond of value of line relationship factor,all reaches 0.9988 above, simultaneously at vitamin C, vitamin C phosphoric acid magnesium and the vitamin C glucose between the vitamin C have the highest sensitivity,vitamin C glucose secondly, the vitamin C phosphoric acid magnesium lowest.
Summary above result, this research of the carbon electrode have an equal, moreover analysis respondence of redox with fairly good reproducibility and stability,to utilize the electrode analyze sensitivity of samples and line relation of samples respond that we can build up a scope of detected with electrode application in the active ingredient,therefore applies this electrode establishment electrochemical the on-line and in-situ absorbed system through the skin that should have a good development potential. |
