A hexafluoroarsenate(V) ion selective PVC membrane electrode based on an ion pair of a lipophilic quaternary ammonium-hexafluoroarsenate is described. Three hexafluoroarsenate salts of tetradodecylammonium (TDA), triheptyldodecylammonium and trioctylmethylammomum ions are evaluated as an anion-exchange site. The TDA salt is estimated to give the best sensitivity. The linear response range of the electrode with a PVC membrane containing TDA-hexafluoroarsenate and di-2-(ethyl- hexyl)phthalate as a solvent mediator is from 10-2M down to 10-7M with a slope of 57~58 mV/decade at pH 2~12. The detection limit is 4X10-8M. The selectivity coefficients of the electrode for anions are determined by the mixed solution method. The electrode based on TDA-hexafluoroarsenate is superior with respects to sensitivity and selectivity to that based on tetradecylphosphonium-hexafluoroarsenate.
All Science Journal Classification (ASJC) codes