W/WO_3/Nafion新型pH修饰电极的研究及其应用

讨论了一种新型pH修饰电极的制备及其应用。将钨(W)电极放置于2 0mol/LH2SO4中,在1 0～2 0V的电位区间内进行电化学氧化,通过该方法在W电极表面生成三氧化钨(WO3)膜。为了排除样品中的污染,在W/WO3电极表面涂敷了一层Nafion(全氟化离子交换剂)膜。该W/WO3/Nafion修饰电极在pH值2.0～12.0的范围内有良好的线性关系,能斯特(Nernstian)斜率为(-53.5±0.5)mV/pH;该电极对pH值6 0～7.0范围内的缓冲溶液响应时间为3s左右;同时,对pH测量过程中的干扰离子、稳定性、寿命和重现性等问题也进行了讨论。最后,还将该修饰pH电极用于多种饮料中pH水平的测定,并和常规的pH玻璃电极进行了比较,获得满意的结果。

Study on the W/WO3/Nafion new pH modified electrode and its application

The preparation of a new pH modified electrode and its application is discussed.The electrode was put into 2.0 mol/L H\-2SO\-4 and was oxidized at an electric potential of 1.0～2.0V. By doing so,the WO\-3 film was created on the surface of the W electrode.To get the sample rid of any impurities, a film of Nafion was applied to the W/WO\-3 electrode,which has good linear relation at the electric potential range of pH 2.0～12.0. The Nernstian gradient was(-53.5±0.5)mV/pH.The response time of the electrode to the buffer solution at pH 6.0～7.0 was only around 3s. The interfering ion,stability,lifespan and reproducibility in the course of pH measurement are discussed. Finally,the modified electrode was applied to measuring the pH level of many drinks and a comparison was made between it and other conventional pH glass electrodes.The results obtained therelf were satisfactory.