微型铂基Nafion固定酶、电子媒体的葡萄糖传感器

A miniaturized glucose biosensor by coimmobilizing glucose oxidase and mediator on a platinum microelectrode

将葡萄糖氧化酶和高氯酸二茂铁同时固定在微盘铂电极表面上的含Nafion的聚电解质内,成功地研制出微型化的葡萄糖传感器,获得了各种优化的实验条件:如稀释Nafion的水溶液中葡萄糖氧化酶的相对浓度、高氯酸二茂铁的浓度以及氧气等对葡萄糖测定的影响。高氯酸二茂铁对过氧化氢具有电催化氧化作用,酶基反应生成的过氧化氢能够在电极表面上用安培法检测。另外,在无氧条件下,高氯酸二茂铁本身也可单独作为葡萄糖氧化酶的电子媒体从而保证该修饰电极的酶循环。Nafion膜具有阳离子交换性能,抗坏血酸在电极上表现出较小的干扰,同时,由于检测电位较低,象尿酸这类需要在较高电位下才能检测的电活性物质在此修饰电极上也无干扰,在无氧条件下,根据Michaehs-Menten方程分析:当C_(Fe)=1.0mmol/L,Miehaelis常数为10.7mmol/L。最大极限电流为5.1nA;当C_(Fe)=2.0mmol/L,Michaelis常数和最大极限电流分别为7.06mmol/L和5.8nA。而且该修饰电极显示了较好的电极稳定性。

A miniaturized glucose biosensor based on the coimmobilization of ferrocene per-chlorate and glucose oxidase in Nafion film at the surface of a microdisk platium electrode was fabricated and successfully used for theamperometric determination of glucose. The influences of various conditional parameters and experimental conditions, including the relative amounts of glucose oxidase in diluted Nafion aqueous solution, the concentration of ferrocene perchlo-rate and oxygen etc, were investigated. The response of glucose on this enzyme electrode was evaluated by the Michaelis-Menten equation, and the results showed that the Michaelis constants and the maximum limiting currents were 10. 7mmol/L and 5. InA, 7. 06mmol/L and 5. 8nA for 1. 0mmol/L and 2.0mmol/L Fc+, respectively. Moreover, this enzyme modified microelectrode showed a good stability for a long-term use.