The Electrochemical Study Of Cu/L-Cys/HRP Layer By Layer Self-assemble Membrane

L-cysteine containing the-SH radical can combine with the metal firmly, and can connect with the enzyme by intermolecular interaction. Therefore, in our laboratory, Horseradish peroxidase (HRP) and L-cysteine(L-Cys) were directly connected on the copper surfaces by using self-assembly method which have been successfully implemented. The ideal results were obtained. In this paper, the L-Cys was used as a linker.Then HRP was further connected to the L-Cys layer by the intermolecular interaction to prepare Cu/L-Cys/HRP self-assembled films. The electrochemical behavior of different self-assembled film electrodes were characterized by cyclic voltammetry and AC impedance spectroscopy. The preparation conditions of the Cu/L-Cys/HRP self-assembled films electrode were explored.The catalytic effects on benzodiazepines of various electrodes such as the bare copper electrode, Cu/HRP electrode, Cu/L-Cys electrode and Cu/L-Cys/HRP electrode films were researched.The full text was divided into five chapters:In the first chapter, an overview of the self-assembly technique, self-assembly films, the status of the research and application of HRP and HRP enzyme electrode were introduced. And the research purpose, significance and innovative points were proposed.The reagents, solutions, experimental apparatus, experimental method and test method were introduced in the second chapter.In the third chapter, L-cysteine was used as a linker to prepare Cu/L-Cys/HRP double self-assembled films. Cyclic voltammetry and AC impedance was performed to determine the optimal preparation conditions. The optimal time for preparation was4h, and the optimal concentration of HRP solution was15mg/L, the optimal pH values of HRP assembly solution were5and7, respectively. To study the film peroperties, the experimental conditions such as the pH of base liquid, temperature, scanning speed were explored. The results showed the optimal pH values were5.5. The optimal temperature was20℃. The stability of the films was good. A good linear relationship between the redox peak current and the square root of the scanning rate was revealed. The oxidation reaction mechanism were for5electrons and5protons.In the fourth chapter, the electrocatalytic effects on benzodiazepines of different electrodes such as the copper electrode, Cu/L-Cys SAMs, Cu/HRP SAMs, Cu/L-Cys/HRP films, were studied.The results showed that the copper electrode could obviously electrocatalyzed catechol. And the optimal pH values for the electrocatalytic effect was8.0. When the concentration was more than50mmol/L, the good electrocatalytic oxidation were revealed. The optimal standing time of electrocatalysis was240s. The optimal temperature of electrocatalysis was35℃. A good linear relationship between the oxidation peak potential and the natural logarithm of the scan rate was found, which showed the reaction mechanism was2protons and2electrons reaction. A good linear relationships between oxidation peak current and the scan rate, and between oxidation peak current and the square root of the scan rate, could be found respectively. The Cu/L-Cys SAMs electrode could obviously electrocatalyze catechol and hydroquinone. And the optimal pH values for the electrocatalytic effect were7.5and6.5, respectively.The optimal concentration of catechol and hydroquinone were15mmol/L and20mmol/L, respectively. The Cu/HRP SAMs electrode could obviously electrocatalyze catechol. The optimal pH range of the electrocatalytic effects was6.0-7.5. And the optimal concentration was15mmol/L.The Cu/L-Cys/HRP electrode could obviously electrocatalyze catechol and hydroquinone. The optimal pH values were7.0,5.5and7.0, respectively. And the optimal concentration were12mmol/L and10mmol/L, respectively. The optimal electrode to electrocatalyze catechol and hydroquinone were Cu/HRP and Cu/L-Cys/HRP, respectively.The fifth chapter was the research summary and outlook.