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A highly selective polymeric membrane barium(II) electrode based on a macrocyclic tetrabasic ligand as neutral carrier
- Ma, Yu-Hua, Yuan, Ruo, Chai, Ya-Qin, Liu, Xin-Lu
- Analytical and bioanalytical chemistry 2009 v.395 no.3 pp. 855-862
- barium, detection limit, electrodes, impedance, ions, nitrates, pH, sulfates, ultraviolet-visible spectroscopy
- A novel barium(II) ion-selective polymeric membrane electrode based on a macrocyclic tetrabasic ligand that derived from the reaction of 4,6-diacetylresorcinol and ethylenediamine in the molar ratio 1:1 as neutral carrier was described. The electrode, with optimum membrane composition, exhibited an excellent near-Nernstian response for Ba²⁺ ion ranging from 3.6 x 10⁻⁶ to 1.0 x 10⁻¹ mol/L with a detection limit of 1.9 x 10⁻⁶ mol/L and a slope of 29.7 ± 0.2 mV/dec in pH 4.0 nitrate buffer solution at 25 °C. It had a relatively fast response time (10 s), good selectivity towards Ba²⁺ ion, and could be used over a wide pH range of 2.5-7.5. Then, the response mechanism was discussed in view of UV-visible spectroscopy and the A.C. impedance technique. Finally, the proposed electrode was successfully applied to the detection of Ba²⁺ ions in real samples as well as in sulfate(II) ions in water.