Investigation to develop a nitric oxide-selective electrode

为实现一氧化氮(NO)的实时检测，研制了一种简便实用的NO选择性电极。工作电极直径0.2 mm，由涂有三层膜的铂/Ir合金制成。对电极是由碳纤维制成的。当施加稳定的NO供体S-亚硝基-N-乙酰-dl-青霉胺时，电极电流呈剂量依赖性增加。电流与计算的NO浓度在0.2nM(S/N=1)~1um NO范围内呈线性关系，电极响应为1.14sy。-.[)0.09s。还研究了温度、pH和NO以外的其他化学物质对电极电流的影响。放置在大鼠主动脉环内侧的电极，由于加入10~(-1)~(-6)~(-1)D_(1M)乙酰胆碱而不产生电流，电流为30pA。在一氧化氮合酶抑制剂D_1-单甲基-L-精氨酸存在下，该电流被消除。因此，这种非选择性电极适用于生物体系中NO的实时测定。NO2 H_2O*NO^-_4H^3E^-。施加大约0.8V的正电压来区分电流和可能的污染物

An NO-selective electrode was developed as an easily applicable tool for a real-time nitric oxide (NO) measurement. The working electrode (0.2 mm diam) was made from Pt/Ir alloy coated with a three-layred membrane. The counterelectrode was made from a carbon fiber. When a stable NO donor, S-nitroso-N-acetyl-dl-penicillamine, was applied, the electrode current increased in a dose-dependent fashion. The current and calculated NO concentration showed a linear relationship in the range from 0.2 nM (S/N=1) to 1 muM of NO.The response of the electrode was 1.14(]SY.+-。[)0.09s. The effects of temperature, pH,and chemicals other than NO on the electrode current were also evaluated. Electrodes which were placed in the luminal side of rat aortic rings exhibited 30 pA of current due to NO generation induced by the addition of 10<@D1-6@>D1M of acetylcholine. The current was eliminated in the presence of 50 muM N<@D1G@>D1-monomethyl-L-arginine, an inhibitor of NO synthase. Thus, this NO-selective electrode is applicable to real-time NO assay in biological systems.NO+2H_2O*NO^-_+4H^++3e^-.A positive voltage of approximately 0.8 V was applied t discriminate against the current from possible contaminant