铂电极上溶液酸碱性的电位溶出法响应

Potentiometric Stripping Analysis of Acidity and Alkalinity of Solutions with Platinum Electrode

提出了一个广谱测定强酸、强碱溶液浓度的方法。用铂电极作工作电极 ,电位溶出法对溶液酸碱性产生响应。通过调节沉积时间和沉积电位 ,利用电位溶出法可以检测溶液酸、碱的浓度范围为 2 .5mol/LH+～ 1.0mol/LOH-。详细研究了不同测定范围的实验条件 ,以及溶出过程的响应机理。在不同酸碱性溶液中电沉积产生的氢吸附于电极表面 ,溶出过程中被溶液中的氧氧化成氢离子 ,从而产生电位平台。该平台的出现还与随后的电极表面金属

A method was proposed to determine the acidity and basicity of solutions by potential stripping analysis using a working electrode of Pt disc. The factors which mainly affect the stripping time are deposition potential (E-d) and deposition time (t(d)), and t(d) was chosen as less than 0.001 s in order to obtain reproducible determination. The solutions ranged from 5.0 mol/L H+ to 1.0 mol/L OH- can be measured by adjustment of deposition potential between - 0.3 similar to -1.2 V. The relative standard deviation was 1.4% for pH 2.0 and 2.1% for pH 10.0 respectively (n = 11). The response mechanism of the method for acidity and basicity has been investigated. The stripping signal is related to the oxidation of hydrogen adsorbed on electrode surface. Hydrogen, whose amount is proportional to the acidity of solution, is oxidized by the oxygen in solution to produce a potential platform where the stripping time is directly proportional to the amount of hydrogen adsorbed on the electrode surface.