An ion selective electrode for mercury(II) based on mercury(II) complex of poly(4-vinyl pyridine)

This study reports on the fabrication, characterization and utilization of the heterogeneous poly(Hg(II)-4-vinyl pyridine) membrane electrode. The electrode, with plasticiser tris(2-ethyl hexyl) phosphate, has a Nernstian response with slope of 30 +/- 1 mV decade(-1) in concentration range of 10(-7)-10(-2) M Hg2+, and in solution of pH 3-4. It has response and life time of less than 25 s and more than 120 days, respectively. Limit of detection is at 0.5 x 10(-7) M Hg2+. interferences from other cations are not serious, except silver(l) at mercury(II) concentration less than 10(-4) M. Analyses of water samples show that the proposed electrode agrees well with the standard method with correlation coefficient, R-2, 0.9998. The electrode is also suitable as an indicator electrode in the potentiometric titration of Hg(II) with iodide. (C) 2008 Elsevier B.V. All rights reserved.