针型钨丝pH传感器的研究及在番茄测试中的应用

Investigations on Tungsten Filament Needle-Concentric pH Sensor and Its Applications in Tomato Sample Analysis

由电聚合法将聚苯胺修饰的钨丝电极作为pH敏感电极,把Ag—AgCl体系填入针型塑料管内构成参比电极,把经聚苯胺修饰的钨丝电极安置入该针型电极内构成复合针型微pH传感器。该传感器在pH2～12范围内呈现Nernst响应,响应时间小于1min。该传感器在测定番茄微区内pH值时获得满意的结果。

A Tungsten filament electrode modified with polyaniline by electro-polymerization was prepared to work as pH-sensitive electrode. A plastics needle filled with Ag/AgCl redox system was used as reference electrode. A micro needle-concentric pH sensor was constructed by inserting the polyaniline-modified Tungsten filament electrode in the needle reference electrode obtained above. The sensor exhibits a linear response in the range 2-12 pH,with a Nernstian response slope of 55mV/pH and a response time of less than 1 min. The results obtained from the sensor are in good agreement with those from the glass pH electrode. The sensor has been successfully employed to determine pH in micro region of tomato.