Berners M O, Boutelle M G, Fillenz M
University Laboratory of Physiology, Oxford, U.K.
Anal Chem. 1994 Jul 1;66(13):2017-21. doi: 10.1021/ac00085a016.
An on-line tubular electrode system is described which provides real time measurements of glutamate in brain microdialysate. It is based on the enzyme glutamate oxidase (EC 1.4.3.11) and the detection of H2O2 on a platinum electrode at 600 mV vs Ag/AgCl. The enzyme is immobilized in a layer of o-phenylenediamine electropolymerized at 750 mV in a phosphate buffer, pH 7.0. The layer is 10-15 nm thick and enables good enzyme loading and fast response time. The ability of the polymer to block out electroactive interferents like ascorbate and uric acid combined with a preoxidation system run at 600 mV resulted in a virtually interference free glutamate assay with a lower detection limit of 0.3 microM in the presence of physiological levels of interferents, a sensitivity of 4 nA/microM, and a linear region up to 30 microM. The system is optimized for use with a microdialysis probe implanted in the brain and perfused at 2 microL/min. It provides a time resolution of < 1 min and has been tested in vivo.
本文描述了一种在线管状电极系统，该系统可实时测量脑微透析液中的谷氨酸。它基于谷氨酸氧化酶（EC 1.4.3.11），并在相对于Ag/AgCl为600 mV的铂电极上检测H2O2。该酶固定在pH 7.0的磷酸盐缓冲液中于750 mV下电聚合的邻苯二胺层中。该层厚度为10 - 15 nm，能实现良好的酶负载量和快速响应时间。该聚合物能够阻挡诸如抗坏血酸和尿酸等电活性干扰物，结合在600 mV运行的预氧化系统，在存在生理水平干扰物的情况下，实现了几乎无干扰的谷氨酸测定，检测下限为0.3 microM，灵敏度为4 nA/microM，线性范围高达30 microM。该系统针对植入大脑并以2微升/分钟灌注的微透析探针进行了优化。它提供了小于1分钟的时间分辨率，并已在体内进行了测试。
