Salicylate-Selective Electrodes Based on Tripodal Tris-thiourea Derivatives

摘要

A new highly salicylate-selective PVC membrane electrode based on tripodal tris-thiourea derivatives, L¹ and L², as neutral carriers is described. The electrodes display an excellent potentiometric response to salicylate ions and an anti-Hofmeister selectivity sequence in the following order: Salicylate^? ClO₄ ^? Benzoate^? I? NO₃^? NO₂^? Maleate^? Acetate^? Lactate^? Fumarate^?. It also exhibited a near-Nernstian potential in a linear range of 5.0 】 10?5 - 1.0 】 10?1 M with a detection limit of 9.0 】 10?5 mol/L and a slope of ?59.9 mV/decade at a pH of 7.0 in a saline buffer solution at 25 oC. The stability constant (log K_S) of the anionsionophore complex was also determined at 25 oC by a conductometric titration in DMSO solution.