A Solid-State Electrochemical Sensor for Determination of Effective Acidity of Aqueous Solutions with High Acidity

A new all. solid state electrode modified with poly(o-aminophenol-co-o-phenylenediamine) film was prepared by cyclic voltammetry. The electrochemical response of the electrode to various solutions in the available acidity range of 1. 00 x 10(-12) -10. 0 mol/L was studied by cyclic voltammetry. The results showed that the reduction peak potentials and the available acidity of solution showed good linear relationship in 3 stages of 1. 00 x 10(-10) -0. 10 mol/L, 0. 10-2. 00 mol/L and 2. 00-10. 0 mol/L respectively, and the regression equations were E-pc = 0. 0456lgC(H+)-0. 295, E-pc = 0. 0803c(H+)-0. 309, and E-pc = 0. 0278c(H+)-0. 188, respectively. There were similar responses in the solutions of H2SO4, HNO3 and HClO4 in the concentration range of 1. 00-8. 00 mol/L. The preparation method of electrode was simple, and the determination range of available acidity was as wide as 1. 0. 10(-10) -10. 0 mol/L, which laid the foundation for the development of solid. state electrochemical sensors for determination of acidity of high acidity solution.