A deuterium–palladium electrode as a new sensor in non-aqueous solutions: potentiometric titration of weak acids in N,N-dimethylformamide and N-methylpyrrolidone

Abstract

A deuterium–palladium electrode was employed as a new indicator electrode for the titration of weak acids in N,N-dimethylformamide and methylpyrrolidone. The investigated electrode showed a linear dynamic response for p-toluenesulfonic acid in the concentration range from 0.1 to 0.001 M, with a nernstian slope of 78.0 mV in N,N-dimethylformamide and of 64 mV per decade in N-methylpyrrolidone. Sodium methylate, potassium hydroxide, and tetrabutylammonium hydroxide proved to be very suitable titrating agents for these titrations. The potential in the course of the titration and at the titration end point was rapidly established. The response time was less than 10–11 s, and the lifetime of the electrode is long. The experimental results obtained for the proposed electrochemical sensor and a conventional glass electrode were in good agreement. The advantages of the electrode are log-term stability, fast response, reproducibility, and easy preparation.