Highly selective potentiometric oxalate ion sensors based on Ni(II) bis-(m-aminoacetophenone)ethylenediamine

Abstract

A plasticized PVC (polyvinyl chloride) membrane based oxalate ion selective electrode has been developed by using the condensation product of m-aminoacetophenone and ethylenediamine. The transition metal complexes of the ligand N,N′-bis(m-aminoacetophenene)ethylenediamine (L) were synthesized and incorporated as ionophore for the synthesis of oxalate ion selective electrodes. Most appropriate result in terms of dynamic range, detection limit and response behavior was determined for the Ni(II) bis-(m-aminoacetophenone) ethylenediamine complex. The electrode demonstrated higher selectivity for oxalate ion with improved performance as compared to other carriers reported in past. The electrode shows Nernstian slope of (-28.5 ± 0.4) mV•decade1 with improved linear range of 1×10 1-1 × 107 mol•L1, with a comparatively lower detection limit in the pH range of 5-10.5, giving a relatively fast response within 10 s and reasonable reproducibility. The selectivity coefficient was calculated using matched potential method and fixed interference method. The lifetime of the electrode was found to be nearly 2 months. The response mechanism and the interaction of oxalate ion with the complexes have been discussed by UV-visible spectroscopic technique. Further the electrode was also successfully applied to determine the oxalate content in water samples. © 2010 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.