The behavior of a poly(aniline) solid contact pH selective electrode basedon N,N,N ',N '-tetrabenzylethanediamine ionophore

A hydrogen ion-selective solid-contact electrode based on N,N,N',N'-tetrabe nzylethanediamine has shown the best Nernstian slope and selectivity and th e widest response range in a Tris buffered pH sample solution. Its linear d ynamic range was pH 3.50 - 11.94, and the Nernstian slope showed 52.1 mV/pH (at 20 +/- 0.2 degreesC). When it was directly applied to human whole bloo d tin pH range 6.0 - 8.5) we could obtain the same satisfying results. This electrode continuously contacted a Tris 7.47 buffered solution, human whol e blood and a hydrofluoric acid solution for one month without any loss of performance. Also, hydrofluoric acid did not influence the surface of this electrode, and thus it was maintained without showing any changes in potent ials after being used in a hydrofluoric acid solution. The standard deviati on in the determined e.m.f. differences was 1.5 mV (N = 5) for Tris buffer solutions of pH 6.5 and 1.1 mV at a Tris buffer solutions of pH 8.5. The 90 % response time of the electrodes obtained by injecting of hydrochloric aci d into the Tris buffer sample solution was less than 10 s. Especially, in t he this paper, with these potential response characteristics of hydrogen io n selective poly(aniline) solid contact electrode, we have also presented t he pH response mechanism of this electrode and the role of poly(aniline) an d a doped anion in a poly(aniline) layer.