A New Lead(II)-Selective PVC-Coated Graphite Rod Electrode Based on a Schiff Base Complex

Abstract

A new lead(II)-selective electrode has been developed based on bis(acetylacetone)-p-phenylenediamine-lead(II) [LPb(NO₃)₂]H₂O complex ionophore as a sensing material, dioctylphthalate (DOP) as a solvent mediator and PVC as a matrix. This electrode exhibits a linear Nernstian response over the concentration range of 1 × 10^-5 - 1 × 10^-1 mol l^-1 of Pb(II) cation, with a cationic calibration slope of 30.0 ± 0.2 mV/concentration decade and a detection limit of 2 × 10^-6 mol l^-1 (0.40 ppm). It has a fast response time and can be used for a period of 2 months without any divergence in potentials. The proposed electrode reveals a good selectivity for Pb(II) over a wide variety of other tested cations and could be used in the pH range of 4 - 8. It was successfully used for direct determination of Pb(II) concentration in some samples. The obtained results show a good agreement with those obtained by an atomic absorption spectrometric method. The average recovery obtained is 96.5 ± 0.5% with standard deviation of 1.2% (n = 8).