Salicylate-selective electrodes based on tripodal tris-thiourea derivatives

Abstract

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°C. The stability constant (log KS) of the anionsionophore complex was also determined at 25°C by a conductometric titration in DMSO solution.