A hydrogen ion-selective poly(aniline) solid contact electrode based on dibenzylpyrenemethylamine ionophore for highly acidic solutions.

Hydrogen-ion selective solid contact electrodes based on tribenzylamine, dibenzylnaphthalenemethylamine, and dibenzylpyrenemethylamine ionophores were prepared. With these electrodes, we showed that the response ranges were influenced by the number of phenyl rings in the ionophores. The lower limits for a linear pH response in acidic solutions were pH 2.50, 0.65, and 0.50, respectively. As the number of phenyl rings in the ionophores increased, the slopes of the EMF responses of these electrodes did not change significantly, but their response extended toward an acidic range (shifted to pH 0.50). Thus, their dynamic response range became wider. A solid contact electrode with dibenzylpyrenemethylamine ionophore, in particular, showed the best selectivity, from the interference of cations and anions, and the best reproducibility of the EMF. This electrode was stored in Tris buffer solutions, artificial serum, and hydrofluoric acid solutions for one month without any loss of performance. Their response time was 8 s. Satisfactory results were obtained when it was tested directly with artificial serum (in pH range 6.0 - 8.5) and hydrofluoric acid.