Highly Selective Salicylate Membrane Electrode Based on N,N'-(Aminoethyl)ethylenediamide Bis(2-salicylideneimine) Binuclear Copper(Ⅱ) Complex as Neutral Carrier

摘要

A new ion selective electrode for salicylate based on N,N'-(aminoethyl)ethylenediamide bis(2-salicylideneimine)binuclear copper(Ⅱ) complex [Cu(Ⅱ)2-AEBS] as an ionophore was developed. The electrode has a linear range from 1.0 × 10-1 to 5.0 × 10-7 mol· L-1 with a near-Nemstian slope of (-55 ± 1) mV/decade and a detection limit of 2.0 ×10-7 mol·L-1 in phosphorate buffer solution of pH 5.0 at 25 ℃. It shows good selectivity for Sal and displays anti-Hofmeister selectivity sequence: Sal- ＞ SCN-＞ ClO4-＞ I- ＞ NO2- ＞ Br- ＞ NO3- ＞ Cl- ＞ SO32- ＞ SO42-The proposed sensor based on binuclear copper(Ⅱ)complex has a fast response time of 5-10 s and can be used for at least 2 months without any major deviation. The response mechanism is discussed in view of the alternating current (AC) impedance technique and the UV-vis spectroscopy technique. The effect of the electrode membrane compositions and the experimental conditions were studied. The electrode has been successfully used for the determination of salicylate ion in drug pharmaceutical preparations.