Analytical Sciences

Highly Selective Iodide Electrode Based on the Copper(II)-N,N′-bis(salicylidene)-1,2-bis(p-aminophenoxy)ethane Tetradentate Complex

Wen-Ju XU, Ya-Qin CHAI, Ruo YUAN, Lan XU, and Su-Li LIU

Chongqing Key Laboratory of Analytical Chemistry, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, P. R. China

In this paper, a new PVC-based liquid-membrane anion-selective electrode based on a copper(II) of N,N′-bis(salicylidene)-1,2-bis(p-aminophenoxy)ethane tetradentate complex (Cu(II)BBAP) is described, which displays a preferential potentiometric response to iodide ion at pH 2.0 and an anti-Hofmeister selectivity sequence: I^- > SCN^- > ClO₄^- > NO₂^- > H₂PO₄^- > NO₃^- > SO₄^2- > Br^- > Cl^-. The electrode exhibits a near-Nernstian potential linear range of 8.2 × 10^-7 - 1.0 × 10^-1 M with a detection limit of 5.3 × 10^-7 M and a slope of -58.8 mV per decade. The A.C. impedance technique and the UV/Vis spectroscopy technique were used to analyze the response mechanism. The electrode could be applied to determine iodide in medicine analysis, and the obtained results were fairly satisfactory.

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