TETRAPHENYLBORATE-SELECTIVE COATED WIRE ELECTRODE BASED ON TETRAPHENYLBORATE-ALKYLTRIPHENYLPHOSPHONIUM DERIVATIVES

A coated wire electrode selectively sensitive to tetraphenylborate ion (TPB-) based on an ion-pair complex of TPB- ion with alkyltriphenylph osphonium derivatives was prepared with poly(vinyl chloride)-membrane plasticized with o-nitrophenyloctyl ether. The electrodes responded wi th Nernstian slopes (ca. 58 mV/decade) over a concentration range of 2 x10(-7)-10(-2) M. A change in pH did not affect the electrode performa nce within the range of pH 5.5-12. The electrodes exhibited very good selectivity for TPB- ion against other organic and inorganic anions. T he reproducibility, stablity, response time and lifetime of the electr ode were studied. The electrode was used to determine benzalkonium and zephiramine in a bactericidal solution with sodium tetraphenylborate as a titrant.