Analytical Sciences

Bis-dimethylaminobenzaldehyde Schiff-Base Cobalt(II) Complex as a Neutral Carrier for a Highly Selective Iodide Electrode

Jianyuan DAI, Yaqin CHAI, Ruo YUAN, Xia ZHONG, Yan LIU, and Dianping TANG

Chongqing Key Laboratory of Analytical Chemistry, Southwest China Normal University, Chongqing 400715, P. R. China

A new solvent polymeric membrane electrode based on N,N′-bis-(dimethylaminobenzaldehyde)-glycine cobalt(II) [Co(II)-BDMABG] as a neutral carrier is described, which displays a preferential potentiometric response to iodide ion and an anti-Hofmeister selectivity sequence in the following order: I^- > ClO₄^- > Sal^- > SCN^- > NO₂^- > Br^- > NO₃^- > Cl^- > SO₃^2- > SO₄^2-. The electrode exhibits a near-Nernstian potential linear range of 9.0 × 10^-7 - 1.0 × 10^-1 M with a detection limit of 6.8 × 10^-7 M and a slope of -53.0 mV/decade in pH 2.0 of a phosphate buffer solution at 20°C. The response mechanism is discussed in view of the A.C. impedance technique and the UV spectroscopy technique. The electrode was successfully applied to the determination of iodide in Jialing River and Spring in Jinyun Mountains with satisfactory results.

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