辣根过氧化物酶在巯基丁二酸铜(II)自组装单分子层修饰电极表面的固定及对H_2O_2传感研究

Incorporation of Horseradish Peroxidase on Self-Assembled Monolayer Modified Electrode by Mercapto-Butanedioic Acid Combined Copper(II) and Study of Sensitivity to H_2O_2

利用气相沉积技术制备TiO2凝胶膜,将辣根过氧化酶固定在巯基丁二酸铜(II)(CuL-SH)自组装单分子层修饰金电极表面,制得测定H2O2的电流型生物传感器.金电极表面的CuL-SH同时作为电子媒介体.研究了各种因素如pH、工作电位等对传感器响应电流的影响.传感器对H2O2的还原显示出快速电催化响应(<10s),计时电流法测定H2O2的线性范围为2.2μmol/L-0.6mmol/L(R=0.999),检出限为1.0×10-6mol/L.测得酶催化动力学参数米氏常数KMapp=0.56mmol/L.传感器的稳定性好,60d其响应值仍保持90%.对其灵敏度和选择性进行了研究,并应用于实际样品测定.

A vapor depositive titania （TiO2） sol-gel film was developed for the fabrication of an amperometric hydrogen peroxide （H2O2） biosensor. The film was used to immobilize horseradish peroxidase （HRP） on a modified Au electrode self-assembled by Mercapto-butanedioic acid combined copper （Ⅱ） （CuL-SH） monolayer which was also employed as an electron mediator. Effects of some experimental conditions such as pH , applied potential on the response current of the biosensor were investigated. The biosensor had a fast response of less than 10 s and linear calibration range of 2.2×10^-6-6. 0 × 10^-4 mol/L with a correlation coefficient of 0. 998 9 and detection limit of 1. 0× 10^-6 mol/L for H2O2. The Michaelis-Menten constant KMapp was found to be 0. 56 mmol/ L. The sensor remains 90 % of its response after using 60 days. Both sensitivity and selectivity of the biosensor were investigated. This method was used to determine the content of H2O2 in the real sample.