Poly(vinyl chloride) membrane electrode on a graphite substrate for the potentiometric titration of tetramethylammonium bromide with sodium tetraphenylborate

Abstract

A poly(vinyl chloride) membrane electrode, based on the ion-pair complex of tetramethylammonium bromide (TMAB) with sodium tetraphenylborate, is described. The electrode exhibits a linear response with a slope of 49 mV per decade of concentration at 20 °C within the range 1 × 10^–4–0.1 M TMAB, at an ionic strength of 0.1 M NaBr. The effect of the pH of the test solution and the interference of other cations and SiO₄^4–(or silicate ions of lower charge such as HSiO₄^3– or H₂SiO₄^2–) were studied. Potentiometric titration was used to determine TMAB, in the presence of SiO₄^4–, with satisfactory results.