Selective uranyl ion detection by polymeric ion-selective electrodes based on salphenH 2 derivatives

Abstract

The new ion-selective electrodes (ISEs) based on salphenH 2 derivatives such as N, N′-(propylenedioxy)benzenebis(salicylideneimine) L 1 and N, N′-4,5-(propylenedioxy)benzenebis(3,5-di- tert-butylsalicylideneimine) L 2 as cation carriers are developed for a uranyl ion. The combination of these new ionophores with tris(2-ethylhexyl)phosphate (TEHP) as a plasticizer particularly shows near Nernstian slope in the wide concentration range (1.0 × 10 −6 to 1.0 × 10 −2 M) of UO 2 2+ and is observed well in the pH range from 1.0 to 5.0 with a response time less than 20 s. Since the employed ionophores were confirmed to form well-defined stable 1:1 complexes with UO 2 2+, the observed high selectivity for a uranyl ion over the other cations was attributed to the selective complexation as well as the lipophilic behavior of these ligands especially for L 2 . The proposed electrodes offered practically low detection limit of 6.5 × 10 −7 M and reasonably good end-points within experimental error were obtained when the sensor was used as an indicator electrode for the potentiometric titration.