Fabrication of Amperometric Hydrogen Peroxide Biosensor Based on Trisoctahedral Nano-Metallic Catalyst and its Applications

• Main Authors: You-syuan Jhai, 翟祐暄
• Other Authors: Meng-jiy Wang
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/7a9fgh

碩士 === 國立臺灣科技大學 === 化學工程系 === 100 === This study was comprised of two parts: (I) the synthesis of trisoctahedral gold nanocrystal (AuNC) and core-shell AuNCs@Pt catalysts for the applications of electrochemical sensing of hydrogen peroxide; (II) the immobilization of enzymatic species by adding cross-linking agent to fabricate electrochemical glucose sensor. For the first part, the surface morphology and crystal lattice of the synthesized nano-metallic catalysts were investigated using SEM, XRD. The synthesized AuNCs showed many active sites due to their polyhedral structure. In order to enhance the catalytic ability, the AuNCs with outer layer of platinum (to form polyhedral nano platinum crystals) was synthesized which provides a particular advantage of only a small amout of platinum was needed. The results of UV-vis spectropy and electrochemical acid treatment showed that the bimetallic catalyst is core-shell structure which was almost completely covered by reduced platinum. The detection of hydrogen peroxide was measured by electrochemical methods. Moreoer, the optimized parameters for electrochemical analyses including the applied voltage and the surface protection layer were applied for the detection of hydrogen peroxide. The results showed that the detection limit of 10 μM, with a linear range of detection from 0.01 to 5.1 mM (R2=0.997), high sensitivity of 397.37 μA/(mMcm2), and excellent anti-interfering ability were obtained for the prepared sensing system. For the second part, the prepared sensing layer on the electrodes was further applied for the detection of glucose. In this study, the synthesized AuNCs were used to adsorb enzyme molecules which were followed by the addition of cross-linking agent to ensure the combination. The enzyme loading and operating parameters were optimized. It showed that the assembled sensor prepared under the optimized condition provided mild environment for enzyme immobilization and facilitated the bio-reaction between enzyme and bio-species, which allowed enzyme exhibiting good affinity and stability. The obtained glucose sensing at 0.5 V v.s Ag/AgCl applied potential showed linear range of 1.0 to 7.0 mM (R2=0.996), with sensitivity of 86.93 μA/mMcm2. We have shown that a highly sensitive glucose biosensor with good reproducibility and precision, high sensitivity, and great stability was successfully prepared.