Talanta 84 (2011) 34–41 Contents lists available at ScienceDirect Talanta journal homepage: www.elsevier.com/locate/talanta Construction of a new Cu 2+ coated wire ion selective electrode based on 2-((2-(2-(2-(2-hydroxy-5-methoxybenzylidene amino)phenyl)disufanyl)phenylimino)methyl)-4-methoxyphenol Schiff base A. Shokrollahi a,∗ , A. Abbaspour b,∗∗ , M. Ghaedi a , A. Naghashian Haghighi a , A.H. Kianfar a , M. Ranjbar a a Department of Chemistry, Yasouj University, Yasouj, Iran b Department of Chemistry, Shiraz University, Shiraz, Iran article info Article history: Received 26 September 2010 Received in revised form 21 November 2010 Accepted 1 December 2010 Available online 9 December 2010 Keywords: Cu 2+ ion selective electrode Potentiometric sensors Coated platinum electrode Schiff base abstract In this article a new coated platinum Cu 2+ ion selective electrode based on 2-((2-(2-(2-(2-hydroxy- 5-methoxybenzylideneamino)phenyl)disufanyl)phenylimino) methyl)-4-methoxyphenol Schiff base (L 1 ) as a new ionophore is described. This sensor has a wide linear range of concentration (1.2 × 10 -7 –1.0 × 10 -1 mol L -1 ) and a low detection limit of 9.8 × 10 -8 mol L -1 of Cu(NO 3 ) 2 . It has a Nern- stian response with slope of 29.54 ± 1.62 mV decade -1 and it is applicable in the pH range of 4.0–6.0 without any divergence in potentioal. The coated electrode has a short response time of approximately 9 s and is stable at least for 3.5 months. The electrode shows a good selectivity for Cu 2+ ion toward a wide variety of metal ions. The proposed sensor was successfully applied for the determination of Cu 2+ ion in different real and environmental samples and as indicator electrode for potentiometric titration of Cu 2+ ion with EDTA. © 2010 Elsevier B.V. All rights reserved. 1. Introduction Copper is an essential element in human body and plays an important role in various biological processes and has widespread occurrence in environmental samples. Large amount of Cu 2+ ion can be tolerated by human beings, however, excessive dosage and long term exposure may cause irritation of the nose, mouth and eyes and it causes headache, stomach ache, dizziness, vomiting and diarrhea. Copper deficiency results in anemia while its accu- mulation resulting in Wilson disease [1]. Copper also has vital importance in biological [2,3], geochemical [4] and industrial sys- tems [5]. In this regard various methods including flame atomic absorption spectroscopy (FAAS), inductively coupled plasma (ICP), voltammetry, coupling of these techniques with preconcentration methods [6–10] and ion selective electrode have been used for trace determination of Cu 2+ ion. Among these methods ion selec- tive electrodes have a wide spread use for the direct determination of ionic species in complex systems and direct potentiometric mea- surement of various ionic species in environmental, industrial and clinical samples [11–21]. In recent decades, many intensive studies have been reported on the design and synthesis of highly selective ∗ Corresponding author. Tel.: +98 741 2223048; fax: +98 741 2223048. ∗∗ Corresponding author. E-mail addresses: ashokrollahi@mail.yu.ac.ir (A. Shokrollahi), abbaspour@chem.susc.ac.ir (A. Abbaspour). ionophores as sensory molecules for ISEs [22,23]. The development of miniaturized and micro sized ISE probes continues to be a “hot” area of research, because most commercial ISEs, with tip diame- ters of the order of 3–15 mm, are regarded as macro in size. One way to reduce the size of conventional ISEs is to remove the inter- nal reference solution [24,25]. Coated wire ion selective electrodes (CWEs) using solid metals such as platinum, copper, or silver as the internal contact wires [26] have been found to be quite use- ful for many direct determinations if the electrodes are calibrated often [24]. The first report on CWEs was published by Cattrall and Freiser [27], since then a variety have been reported [14,28]. In this procedure electroactive species directly incorporated into a thin polymeric film coated directly on a metallic or graphite conductor have been shown to be very effective for a wide variety of inor- ganic and organic ions [29–34]. Electrodes of this sort has unique advantages including simplicity, low cost, durability, capability of reliable response in a wide concentration range for a wide variety of both organic and inorganic ions and suitable for measurements in small volumes of sample or for the desired in vivo applications. In comparison with most commercially available electrodes, these electrodes were readily prepared and had high sensitivities with a low detection limits [26,35]. The purpose of this work is the development of Cu 2+ ion selec- tive electrode based on plasticized PVC membranes containing L 1 with high selectivity toward Cu 2+ ion as the membrane active ingredients coated on the surface of platinum wire electrode. The selectivity for a variety of ions and the effect of the membrane 0039-9140/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.talanta.2010.12.002