Novel Ionophores for Barium-Selective Electrodes: Synthesis and Analytical Characterization

• Published in: Electroanalysis (New York, N.Y.) Vol. 22; no. 19; pp. 2147 - 2156
• Main Authors: Peshkova, Maria A., Timofeeva, Natalia V., Grekovich, Alexander L., Korneev, Sergei M., Mikhelson, Konstantin N.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01-10-2010; WILEY‐VCH Verlag
• Subjects: Barium; Characterization; Complex formation; Constants; Derivatives; Electrodes; Ionophores; Mathematical analysis; Membranes; Selectivity; Sensors; Synthesis
• ISSN: 1040-0397; 1521-4109; 1521-4109
• DOI: 10.1002/elan.201000222

A novel way of synthesis is developed for the Ba2+ selective neutral Ionophore 2a: 2,2′‐[1,2‐phenylenebis(oxyethane‐2,1‐diyloxy)]bis(N‐benzyl‐N‐phenylacetamide) and its methyl (2b), buthyl (2c), and hexyl (2d) derivatives. Ba2+ selective electrodes based on Ionophores 2a–d are compared with those with commonly used Ionophore 1: N,N,N′,N′‐tetracyclohexyl‐oxybis(o‐phenyleneoxy) diacetamide. It is shown that Ionophores 2a–d, particularly 2b, are superior for measurements of Ba2+ in the presence of Ca2+, and in acidic solutions. Segmented sandwich membrane studies suggest formation of complexes IL22+ for Ba2+, Ca2+ and Mg2+ ions with Ionophore 2b, while H+ ions apparently form complexes H2L2+. The values of the complex formation constants are consistent with the selectivity coefficients.