Novel potentiometric sensor for monitoring barium(II) based on 2,3,4-pyridine-1,3,5,7,12-pentaazacyclopentadeca-3-ene

Abstract

A poly (vinyl chloride)-based membrane of 2,3,4-pyridine-1,3,5,7,12-pentaazacyclopentadeca-3-ene with sodium tetraphenylborate(NaTPB) as an anion excluder and dioctyl phthalate (DOP) as plasticizer was prepared and investigated as a Ba(II)-selective electrode. The best performance was observed with the membrane having the ligand–PVC–DOP–NaTPB composition 1:4:1:1, which worked well over a wide concentration range (1.41 × 10 −6–1.0 × 10 −1 mol L −1) with a Nernstian slope of 30.0 mV per decade of activity between pH 2.5 and 7.0. This electrode showed a fast response time of 18 s and was used over a period of 3 months with good reproducibility ( S = 0.4 mV). The selectivity coefficient for mono-, di- and trivalent cations indicates excellent selectivity for Ba(II) ions over a large number of cations. Electrode works satisfactorily in methanolic and ethanolic content up to a maximum of 30%. The sensor has been used as an indicator electrode in potentiometric titration of Ba(II) with EDTA.