www.jocpr.com Available on line Journal of Chemical and Pharmaceutical Research ISSN No: 0975-7384 CODEN(USA): JCPRC5 J. Chem. Pharm. Res., 2011, 3(4):551-555 551 Fabrication of Eu 3+ Polymeric Membrane Ion-Selective Sensor Hassan Ali Zamani, a,* Neda Rohani, a Mohammad Reza Abedi, a Soraia Meghdadi, b a Department of Applied Chemistry, Quchan branch, Islamic Azad University, Quchan, Iran b Department of Chemistry, Isfahan University of Technology, Isfahan, Iran ______________________________________________________________________________ ABSTRACT A new Eu(III) PVC membrane sensor has been constructed by using 1,4-bis[o-(thiophene-2- carboxamidophenyl)]-1,4-dithiobutane (TCD) as a suitable ion carrier. The proposed electrode based on (TCD) with nitrobenzene (NB) as a solvent mediator in a poly(vinyl chloride) membrane matrix exhibited a near-Nernstian response to Eu 3+ in the concentration range of 1.0 × 10 -6 to 1.0 × 10 -2 M with a slope of 19.5 mV per decade of activity of Eu 3+ , a relatively fast response of ~5 s in a wide pH range 2.7-8.8. The lower limit of detection was 6.7 × 10 -7 M. Keywords: PVC Membrane, Potentiometry, Ion-Selective Electrode, Sensor. ______________________________________________________________________________ INTRODUCTION Construction and then application of ion-selective electrode as a potentiometric sensor offers interesting advantages such as simplicity, speed, fast response, low cost, wide linearity range and procedure. These characteristics have inevitably led to sensors for ionic species. Although instrumental techniques such as inductively couple plasma atomic emission spectrometry (ICP- AES), neutron activation analysis, mass spectrometry (MS), X-ray fluorescence spectrometry, inductively couple plasma mass spectrometry (ICP-MS), Isotope dilution mass spectrometry, etc, provide an accurate measurement in trace amount of elements. But all of these methode are expensive and need complicated equipmens [1,2]. In this paper we report a highly selective europium electrode using 1,4-bis[o-(thiophene-2-carboxamidophenyl)]-1,4-dithiobutane (TCD) as an active material in poly vinyl chloride matrix for the preparation of Eu 3+ -selective electrode. EXPERIMENTAL SECTION Analytical reagent grade chemicals and triply-distilled water were used for preparing all aqueous solutions. The ionophore 1,4-bis[o-(thiophene-2-carboxamidophenyl)]-1,4-dithiobutane was prepared as formerly described [3-6]. The high molecular weight PVC powder, dibutyl phthalate