Department of Chemistry and Environmental Engineering, Hunan City University, Yiyang, P.R. China Abstract: A novel approach to assemble an H2O2 amperometric biosensor was introduced. The biosensor was constructed by entrapping horseradish peroxidase (HRP) labeled nano-scaled particulate gold (nano-Au) (HRP-nano-Au electrostatic composite) in a new silica sol-gel/alginate hybrid film using glassy carbon electrode as based electrode. This suggested strategy fully merged the merits of sol-gel derived inorganic-organic composite film and the nano-Au intermediator. The silica sol-gel/alginate hybrid material can improve the properties of conventional sol-gel material and effectively prevent cracking of film. The entrapment of HRP in the form of HRP-nano-Au can not only factually prevent the leaking of enzyme out of the film but also provide a favorable microenvironment for HRP. With hydroquinone as an electron mediator, the proposed HRP electrode exhibited good catalytic activity for the reduction of H2O2. The parameters affecting both the qualities of sol-gel/ alginate hybrid film and the biosensor response were optimized. The biosensor exhibited high sensitivity of 0.40 Al mol21 cm22 for H2O2 over a wide linear range of concentration from 1.22 ⨯ 1025 to 1.46 ⨯ 1023 mol L21, rapid response of ,5s and a detection limit of 0.61 ⨯ 1026 mol L21. The enzyme electrode has remarkable Received 10 May 2005; accepted 1 June 2005 The authors thank the Scientific Research Fund of Hunan Provincial Education Department (04C160) and Hunan Provincial Natural Science Foundation of China (04JJ40017) for financial support. Address correspondence to Cun-Xi Lei, Department of Chemistry and Environmental Engineering, Hunan City University, Yiyang 413049, P.R. China. E-mail: leicunxi@163.com
