Pandey P C, Singh G
Department of Chemistry, Banaras Hindu University, Varanasi 221 005, India.
Talanta. 2001 Oct 31;55(4):773-82. doi: 10.1016/s0039-9140(01)00505-7.
A novel pH sensor suitable for use in both aqueous and non-aqueous mediums is reported. The sensor is derived from polymer modified electrode obtained from electrochemical polymerisation of aniline in dry acetonitrile containing 0.5 M tetraphenyl borate at 2.0 V versus Ag/AgCl. The light yellow colour polymer modified electrode obtained under the present experimental condition has been characterised by scanning electron microscopy (SEM). The pH sensing of polymer modified electrode in both aqueous and non-aqueous mediums is examined and reported. As the typical examples, we used weak acid (acetic acid) and weak base (ammonium hydroxide) as analytes. The acetic acid is analysed in both aqueous and dry acetonitrile whereas ammonium hydroxide is analysed only in aqueous medium. The analysis in aqueous medium is conducted in 1 mM Tris-HCl buffer pH 7.0 and also in 0.1 M KCl. The slope of pH sensing is calculated from the data recorded in typical buffers and found to be approximately 86 mV per pH. The application of polymer modified electrode for the construction of urea biosensor is described based on immobilised urease within poly vinyl alcohol (PVA) matrix and also within organically modified sol-gel glass on the surface of polymer-modified electrode. The new urea sensor has shown maximum response of 160 mV at 25 degrees C with a lowest detection limit of 20 muM. The performance of new pH sensor and urea sensor has been studied and reported in this communication.
报道了一种适用于水性和非水性介质的新型pH传感器。该传感器源自通过在含有0.5 M四苯基硼酸盐的干燥乙腈中于2.0 V（相对于Ag/AgCl）对苯胺进行电化学聚合而获得的聚合物修饰电极。在当前实验条件下获得的浅黄色聚合物修饰电极已通过扫描电子显微镜（SEM）进行了表征。研究并报道了聚合物修饰电极在水性和非水性介质中的pH传感。作为典型示例，我们使用弱酸（乙酸）和弱碱（氢氧化铵）作为分析物。乙酸在水性和干燥乙腈中均进行分析，而氢氧化铵仅在水性介质中进行分析。在水性介质中的分析在pH 7.0的1 mM Tris-HCl缓冲液以及0.1 M KCl中进行。根据在典型缓冲液中记录的数据计算pH传感的斜率，发现其约为每pH 86 mV。基于将脲酶固定在聚乙烯醇（PVA）基质中以及聚合物修饰电极表面的有机改性溶胶-凝胶玻璃中，描述了聚合物修饰电极在构建尿素生物传感器中的应用。新型尿素传感器在25℃下显示出最大响应为160 mV，最低检测限为20μM。本通讯中研究并报道了新型pH传感器和尿素传感器的性能。
