title: Optimization of polymeric triiodide membrane electrode based on clozapine-triiodide ion-pair using experimental design.
abstract: Central composite design (CCD) and response surface methodology (RSM) were developed as experimental strategies for modeling and optimization of the influence of some variables on the performance of a new PVC membrane triiodide ion-selective electrode. This triiodide sensor is based on triiodide-clozapine ion-pair complexation. PVC, plasticizers, ion-pair amounts and pH were investigated as four variables to build a model to achieve the best Nernstian slope (59.9 mV) as response. The electrode is prepared by incorporating the ion-exchanger in PVC matrix plasticized with 2-nitrophenyl octal ether, which is directly coated on the surface of a graphite electrode. The influence of foreign ions on the electrode performance was also investigated. The optimized membranes demonstrate Nernstian response for triiodide ions over a wide linear range from 5.0 x 10(-6) to 1.0 x 10(-2)mol L(-1) with a limit of detection 2.0 x 10(-6) mol L(-1) at 25 degrees C. The electrodes could be used over a wide pH range 4-8, and have the advantages of easy to prepare, good selectivity and fast response time, long lifetime (over 3 months) and small interferences from hydrogen ion. The proposed electrode was successfully used as indicator electrode in potentiometric titration of triiodide ions and ascorbic acid.
authors.affiliation: Department of Chemistry, Faculty of Science, Urmia University, Urmia, Iran. khfarhadi@yahoo.com
authors.forename: Khalil
authors.initials: K
authors.lastname: Farhadi
authors.forename: Morteza
authors.initials: M
authors.lastname: Bahram
authors.forename: Donya
authors.initials: D
authors.lastname: Shokatynia
authors.forename: Floria
authors.initials: F
authors.lastname: Salehiyan
mesh_terms: D001205:Ascorbic Acid / Q000032:analysis; D003024:Clozapine; D006108:Graphite; D006863:Hydrogen-Ion Concentration; D007454:Iodides / Q000032:analysis*; D017736:Ion-Selective Electrodes / Q000592:standards*; D008722:Methods; D011143:Polyvinyl Chloride; D012680:Sensitivity and Specificity
chemical_list: D007454:Iodides; D006108:Graphite; D011143:Polyvinyl Chloride; D003024:Clozapine; D001205:Ascorbic Acid