Analytical Sciences

Abstract − Analytical Sciences, 23(2), 171 (2007).

Salicylate Ion-Selective Electrode Based on New Tetranuclear Copper Complexes of O-Vannlin-methionine as Neutral Carriers
Guangrong YE, Yaqin CHAI, Yuan RUO, Lu ZHOU, Yan LI, and Lina ZHANG
Chongqing Key Laboratory of Analytical Chemistry, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, P. R. China
A new salicylate-selective PVC membrane electrode based on a new Schiff base tetranuclear copper complex of O-vannlin-methionine (Cu(II)4-TVM) as a neutral carrier is described. This electrode displays a preferential potentiometric response to salicylate and an anti-Hofmeister selectivity sequence in the following order: Sal- > ClO4- > SCN- > I- > NO2- > NO3- > Br- > Cl- > SO32- > SO42- > H2PO4-. The electrode exhibits near-Nernstian potential linear range of 1.5 × 10-6 - 1.0 × 10-1 M with a detection limit of 8.0 × 10-7 M and a slope of -56.3 mV/decade in pH 3.0 - 8.0 of phosphorate buffer solution at 20°C. Thanks to the tetranuclear copper(II) in the carrier, the electrode has the advantages of simplicity, fast response, fair stability and reproducibility and low detection limit. The response mechanism to the electrodes is discussed by the a.c. impedance technique and the UV spectroscopy technique. The electrode can be applied to analyses of medicine and the results obtained are in fair agreement with the results given by a standard method.