PVC-membrane potentiometric sensors based on a recently synthesized Schiff base for Fe(III) ion

Abstract

A potentiometric iron sensor based on the use 3-(2-diethylamino-ethylimino)-1,3-dihydro-indol-2-one (DEDIO) as an ionophore in poly(vinyl chloride) (PVC) matrix, is reported. The plasticized membrane sensor exhibits a Nernstian response for Fe(III) ions over a wide concentration range (2.0 × 10^-6 - 5.0 × 10^-2 M) with a super Nernstian slope of 26(±1) mV per decade. It has a fast response time of <12 s and can be used for ten weeks without any considerable divergences in its potentials .the electrode can be used in the pH range 4.5-8.0. The proposed sensor shows fairly good discriminating ability towards Fe(III) ion in comparison with a large number of alkali, alkaline earth, transition and heavy metal ions. The sensor was used as indicator electrode in potentiometric titration of Fe(III) ions vs. EDTA.

KEY WORDS: Iron, Ion selective electrode, PVC membrane, Schiff base, Potentiometry

Bull. Chem. Soc. Ethiop. 2012, 26(1), 65-72.

DOI: http://dx.doi.org/10.4314/bcse.v26i1.7