The Preparation And Application Of The Hydrogen Peroxide Biosensor Based On Gelatin-Hierarchical Porous Carbon

Biosensors for continuous application are becoming more important, and long-life biosensors have not been commercialized due to the lack of stability of its components. Taking into account of these problems, the highly stable biosensors based on gelatin-hierarchical porous carbon have been developed in this work, and their performance and application were systematically studied. Specific works are as follows:Firstly, a physical adsorption-chemical crosslinked method was used to achieve the immobilization of catalase. A highly stable third-generation hydrogen peroxide biosensor modified by gelatin-hierarchical porous carbon was successfully prepared. As the dispersing agent of the electrode materials, gelatin can disperse the hierarchical porous carbon well and obtain a stable and uniform suspension. The biocompatibility of gelatin can provide a suitable environment for the catalase to maintain high activity. The hierarchical porous structure of hierarchical porous carbon obtained from fish scales and the uniform porous structure of the composite film provide channels for ions rapid transfer, and promote the direct electron transfer between enzyme and electrode surface. This biosensor exhibited a good catalytic performance for H2O2, and showed a linear range from 0.2 to 10.7 mM, low detection limit of 0.7 μM and a sensitivity of 74.69 μAmM-1cm=2. Also, the modified electrode exhibited strong interference immunity and high operational stability and long-term storage stability. When used to determine the H2O2 in milk, the recoveries were around 97%～103%.Secondly, with gelatin as the multifunctional agent and ascorbic acid as the reducing agent, silver nanoparticles have been prepared by reducing silver nitrate. A highly stable enzyme-free hydrogen peroxide biosensor based on gelatin/silver nanoparticles-hierarchical porous carbon was successfully prepared. The hierarchical porous carbon do not only promote the direct electron transfer between enzyme and electrode surface, but also obviously increase the stability of biosensor cooperating with gelatin. This enzyme-free biosensor exhibited excellent amperometric response towards H2O2 in the linear concentration range from 0.2 to 12.3 mM, low detection limit of 0.6 μM and a sensitivity of 228.92 μAmM-1cm-2. Moreover, the developed biosensor exhibited good interference immunity and long-term stability. When used to determine the H2O2 in milk, the recoveries were raound 97%-103%. And it would pave a good platform to enzyme-free determination of H2O2.