Cobalt(II)-selective membrane sensor based on a Me-2(13)dieneN(4) macrocyclic cobalt complex

摘要

A new poly(vinyl chloride)-based membrane was fabricated with the cobalt(II) complex of 2,4-dimethyl-1,5,8,11-tetraazacyclotrideca-1,4-diene Me-2(13) dieneN(4) as an ion carrier. The membrane composition was Co2+ complex/ PVC/ NaTPB/ DBP 15: 50: 15: 20 (w/ w). The sensor exhibited a Nernstian response for Co2+ ions over a wide concentration range (7.94 x 10(-6) -1.0 x 10(-1) M) at pH 2.5 -7.0, a response time of 10 s, and it could be used for 3 months without any significant divergence in potential. The proposed membrane sensor exhibited good selectivity for Co2+ over a wide variety of other metal ions and in mixtures containing up to 25 (v/ v) non-aqueous content. The sensor was successfully used as an indicator electrode in the potentiometric titration of Co2+ with EDTA and the direct determination of Co2+ in real samples.