辣根过氧化物酶生物传感器的制备及其应用于过氧化氢的测定

Preparation of Horseradish Peroxidase Biosensor and Its Application to the Determination of Hydrogen Peroxide

通过将碳纳米管及二氧化钛复合材料（CNT-TiO2）修饰于金电极表面,并借其对辣根过氧化物酶的静电吸附和对羧酸基的高反应特性,使辣根过氧化物酶（HRP）固定在CNT-TiO2表面,制成了辣根过氧化物酶生物传感器（HRP-CNT-TiO2）。对此修饰电极在磷酸盐缓冲介质（pH7.2）中的电催化性质及其电催化反应的最佳条件作了研究。试验结果表明,此电极对过氧化氢有很好的电催化特性,且发现当过氧化氢的浓度在4.2×10^-7-3.2×10^-4mol·L^-1之间与ΔI之间呈线性关系,检出限（S/N=3）为7.2×10^-8mol·L^-1。为试验方法的精密度,对过氧化氢的浓度水平为5×10^-5mol·L^-1的条件下进行了8次测定,结果的RSD值为4.5%。

A horseradish peroxidase （HRP） biosensor was prepared by modifying the gold electrode with the composite material of carbon nanotube and titanium dioxide （CNT-TiO2）, and immobilizing the HRP on CNT-TiO2 through its electrostatic adsorption and high reactivity to carboxyl group. The electrocatalytic behavior of the biosensor in a phosphate buffer of pH 7.2, and the optimum conditions of the electrocatalytic reaction were studied. It was found by cyclovoltammetric study that good electrocatalyfic activity of the HRP-CNT-TiO2 biosensor toward hydrogen peroxide was observed. Linear relationship between ΔI and concentration of H2O2 was obtained in the range of 4.2×10^-7-3.2×10^-4mol·L^-1, and the detection limit （S/N=3） was found to be 7.2×10^-8mol·L^-1. Test for precision was made at the concentration level of 5×10^-5mol·L^-1 of H2O2 for 8 determinations, value of RSD found was 4. 5%.