Analytica Chimica Acta 418 (2000) 197–203 A bromide ion-selective polymeric membrane electrode based on a benzo-derivative xanthenium bromide salt Mojtaba Shamsipur a,∗ , Shohreh Rouhani b , Ali Mohajeri c , Mohammad Reza Ganjali c , Parviz Rashidi-Ranjbar c a Department of Chemistry, Razi University, Kermanshah, Iran b Department of Chemistry, Bou-Ali Sina University, Hamadan, Iran c Department of Chemistry, Tehran University, Tehran, Iran Received 29 December 1999; received in revised form 17 April 2000; accepted 1 May 2000 Abstract A novel bromide ion-selective PVC membrane sensor based on 14-phenyldibenzo[a,j]xanthenium bromide as a membrane carrier was prepared. The electrode has a linear dynamic range between 1.0×10 −1 and 3.2×10 −5 M with a near-Nernstian slope of 61±1 mV per decade and a detection limit of 2.0×10 −5 M. The potentiometric response is independent of the pH of the solution in the pH range 4.5–8.5. The electrode possesses the advantages of low resistance, fast response and good selectivities over a variety of other anions. It was applied as an indicator electrode in potentiometric titration of bromide ions. © 2000 Elsevier Science B.V. All rights reserved. Keywords: Bromide ion-selective electrode; 14-Phenyldibenzo[a,j]xanthenium bromide; PVC membrane; Potentiometry 1. Introduction To date, a wide variety of carrier-based ion-selective polymeric membranes for chloride [1–8] and iodide [9–15] ions have been reported in the literature and their widespread use in clinical chemistry are well established [16–19]. These electrodes usually employ various types of anion carriers including lipophilic cationic salts, quaternary ammoniums, organometal- lic compounds, vitamin B 12 derivatives, metallopor- phyrins, Schiff base complexes and other cationic complexes. In comparison, the literature reports on the ion-selective sensors that can directly monitor Br − ions in different aqueous solutions are quite ∗ Corresponding author. Tel.: +98-831-723307; fax: 98-831-831618. sparse [20–22]. The reported bromide ion-selective electrodes are based on heterogeneous membranes containing silver bromide. To the best of our knowl- edge, there is no previous report on the carrier-based ion-selective membrane sensors for bromide ion. We have recently introduced PVC-based membrane sensors for K + [23], Be 2+ [24], Sr 2+ [25], Zn 2+ [26], Pb 2+ [27,28], Hg 2+ [29,30], Ag + [31], I 3 − [32], I − [33] and SCN − [34] ions based on different noncyclic and macrocyclic ligands (for cations) and metallopor- phyrin and charge-transfer complexes (for anions). Due to the vital importance of bromide determination in chemical, industrial and clinical analyses [35], we were interested in the preparation of a new solvent polymeric membrane sensor for selective monitoring of Br − ion in solution. In this paper, we report a se- lective PVC membrane electrode for Br − ion based 0003-2670/00/$ – see front matter © 2000 Elsevier Science B.V. All rights reserved. PII:S0003-2670(00)00954-5