CHARACTERIZATION OF GLUCOSE OXIDASE-MODIFIED POLY(PHENYLENEDIAMINE)-COATED ELECTRODES IN-VITRO AND IN-VIVO - HOMOGENEOUS INTERFERENCE BY ASCORBIC-ACID IN HYDROGEN-PEROXIDE DETECTION
CHARACTERIZATION OF GLUCOSE OXIDASE-MODIFIED POLY(PHENYLENEDIAMINE)-COATED ELECTRODES IN-VITRO AND IN-VIVO - HOMOGENEOUS INTERFERENCE BY ASCORBIC-ACID IN HYDROGEN-PEROXIDE DETECTION
复制标题
DOI：
10.1021/ac00082a025
复制
发表时间：
1994-05-15
影响因子：
7.4
通讯作者：
ONEILL, RD
中科院分区：
文献类型：
--
作者：
LOWRY, JP;MCATEER, K;ONEILL, RD
葡萄糖氧化酶 (GOx) 修饰的聚邻苯二胺涂层 Pt 圆盘电极对葡萄糖的响应表现良好，响应时间快，并显示米氏动力学。然而，当在含有抗坏血酸的溶液中进行葡萄糖校准时，葡萄糖响应以浓度依赖性方式降低。研究了均相氧化还原反应的可能性，其中 GOx/聚合物表面葡萄糖酶促氧化产生的 H2O2 被抗坏血酸消耗。不涉及膜的 GOx 改性碳粉电极以及裸 Pt 电极上的 H2O2 校准的类似“负”干扰支持了这一假设。观察到这种干扰可以被螯合剂 EDTA 阻断，这表明均相反应是由溶液中的痕量金属离子杂质催化的。基于这些实验结果提出了均相反应模型，并通过比较静态和搅拌溶液进行了测试。没有观察到尿酸的均匀干扰。发现电极在体外没有脂质污染，并且体内监测脑葡萄糖水平的实验表明在该环境中不存在均相反应。结果强调需要在相关条件下测试涉及 H2O2 的每个单独测定程序，以检测抗坏血酸的正面和负面干扰。
The response of glucose oxidase (GOx) modified poly(o-phenylenediamine) coated Pt disk electrodes to glucose was well-behaved with a rapid response time and displaying Michaelis-Menten kinetics. However, the glucose response was lowered in a concentration-dependent manner by ascorbic acid when the glucose calibrations were carried out in solutions containing this reducing agent. The possibility of a homogeneous redox reaction in which the H2O2 generated by tie enzymatic oxidation of glucose at the GOx/polymer surface is consumed by ascorbate was investigated. Similar ''negative'' interference at GOx-modified carbon powder electrodes not involving membranes and for H2O2 calibrations at bare Pt electrodes supported the hypothesis. The observation that this interference could be blocked by the chelating agent EDTA suggests that the homogeneous reaction is catalyzed by trace metal ion impurities in solution. A model for the homogeneous reaction based on these experimental findings is proposed and tested by comparing quiescent and stirred solutions. No homogeneous interference by uric acid was observed. The electrodes were found to be free from lipid fouling in vitro, and experiments monitoring brain glucose levels in vivo indicate the absence of the homogeneous reaction in this environment. The results highlight the need to test each individual assay procedure involving H2O2 under relevant conditions for both positive and negative interference by ascorbic acid.