REVIEWS IN ANALYTICAL CHEMISTRY, cilt.28, sa.1, ss.51-65, 2009 (SCI-Expanded)
A new solid-state membrane ion-selective electrode sensitive to Pb(II) ions was developed. Two different methods based on two different sulfide preparation techniques were employed to make up the membrane of the electrode. The electrodes with the membranes prepared by these two methods did not show any appreciable difference in performance. The proposed electrode exhibited a Nernstian slope of 28.3 +/- 0.2 mV/pPb over a wide working range from 1.0 x 10(-1) to 1.0 x 10(-5) M. It has a fast response time (< 10 s), a satisfactory reproducibility and a relatively long lifetime (> a year) without any considerable divergence in potential. The selectivity coefficients of thirteen cations were determined by the fixed interference method and the electrode showed a fairly good selectivity to Pb2+ ion in comparison to other common cations, namely Cd2+, Cu2+, Co2+, Fe2+, Ni2+, Ca2+, Mg2+, Ba2+, Mn2+, Zn2+ and Sr2+. It was found that only Ag+ and Hg2+ had an interfering effect. The influence of pH was studied and the potential response was independent of the pH of the test solutions in the range 3.5-6.0. It was successfully used as an indicator electrode in the potentiometric titration of lead ions with EDTA to determine the lead contents of a standard lead solution and standard lead samples. The results obtained were compared with those obtained by the use of commercial Pb(II)-selective electrode. Such a Pb(II)-selective electrode, proposed here, can be constructed for commercial purposes.