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): 814-819 814 Investigation of response behavior of a Lu 3+ ion-selective sensor in presence of interfering ions Hassan Ali Zamani, * Mohammad Reza Abedi Department of Applied Chemistry, Quchan branch, Islamic Azad University, Quchan, Iran _____________________________________________________________________________ ABSTRACT A selective and sensitive polymeric membrane sensor based on the incorporation of Di-tert- butyl-1-(tert-butyl thio)-1,2-hydrazine dicarboxylate as a sensing compound in a poly(vinylchloride) (PVC) for the determination of the Lu 3+ ions was constructed.. The membrane sensor further comprises nitrobenzene (NB) as a plasticizer, and the role of sodium tetraphenyl borate (NaTPB) as an anionic additives was also evaluated. To investigate the membrane electrode selectivity, its potential response was monitored in the presence of various interfering foreign cations using the matched potential method. The sensor's selectivity against a lot of common alkaline, alkaline earth, transition, heavy metals and specially lanthanide ions was very good. The developed sensor was successfully applied as an indicator electrode in Lu 3+ ion potentiometric titration with EDTA. The constructed sensor accuracy was investigated by the monitoring of Lu 3+ in mixtures of two and three different ions. Keywords: Sensor, PVC membrane, Potentiometry, Ion selective electrode. _____________________________________________________________________________ INTRODUCTION Solvent polymeric membrane based ISEs, together with the incorporation of new ion carriers, have shown to be a very useful tool for clinical, environmental, and chemical analyses as well as for process monitoring. In the area of membrane based ISEs, emphasis has been focused on the development of new ion-carriers. Fabrication of a new, ionspecific ISEs with high selectivity and sensitivity, wide linear concentration range, long lifetime and good reproducibility, is always in need [1, 2]. The fact that lanthanides have similar chemical and physical properties, makes their analyses an extremely time consuming and complicated procedure, especially in case other similar ions are present in the sample solution [3]. Lutetium is one of the rare elements that can