Triiodide Ion-Selective Electrode Based on Charge-Transfer Complex of 4,7,13,16,21,24-Hexaoxa-1,10-diazabicyclo-[8.8.8]hexacosane (original) (raw)
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Two new highly selective triiodide electrodes have been prepared using charge-transfer complex of iodine with cryptand 222 as an electroactive ionophore and nitrophenyl octyl ether as a plasticizing agent. The electrodes showed Nernstian response to triiodide ions over a concentration range from 1.0´10 -2 -7.9´10 -7 M and from 1.0´10 -2 -1´10 -6 M with detection limits of 6.3´10 -7 and 7.9´10 -7 M for cryptand and its charge-transfer complex with iodine, respectively. The response times (t 95% ) of the sensors were 10 and 5 s. The membrane could be used for more than 1 month without any divergence in potentials. The proposed sensors exhibited very high selectivity for triiodide ion over other anions, and could be used in a wide pH range~2-10. These electrodes were successfully applied as an indicator electrode in potentiometric titration of copper in ore samples.
Analytical Chemistry, 1999
A novel triiodide ion-selective electrode based on a chargetransfer complex of iodine with 2,4,6,8-tetraphenyl-2,4,6,8-tetraazabicyclo[3.3.0]octane as membrane carrier was prepared. The electrode has a linear dynamic range between 5.0 × 10 -2 and 3.5 × 10 -6 M, with a near-Nernstian slope of 54.7 ( 0.8 mV decade -1 and a detection limit of 2.0 × 10 -6 M. The potentiometric response is independent of the pH of the solution in the pH range 4.0-10.5. The electrode possesses the advantages of low resistance, short conditioning time, fast response, and, especially, very good selectivities over a wide variety of other anions. The electrode can be used for at least 10 months without any considerable divergence in potentials. It was used as an indicator electrode in potentiometric titration of triiodide ions.
A new triiodide ion-selective electrode based on a charge-transfer complex of iodine with ditertbutyldicyclohexyl-18-crown-6 (t-Bu) 2 DC18C6 as membrane carrier was prepared. The electrode has a linear dynamic range from 6.3´10 -3 -5´10 -6 with a Nernstian response of 58.6 ± 1 mV decade -1 and a detection limit of 1.3´10 -6 M. The response time of the sensor was 25 s. The membrane could be used for two months without any divergence in potentials. The electrode exhibits an anti-Hofmeistetr selectivity sequence with a preference for triiodide at pH 2.0-10.0. The response mechanism of the electrode was investigated by Uv-Vis spectroscopic technique. The electrode can be used for the determination of ascorbic acid in orange juice.
Triiodide PVC Membrane Electrodes Based on Charge-Transfer Complexes
Analytical Chemistry, 2002
Three new electrodes were prepared by incorporating two different charge-transfer complexes and amino crown ether into plasticized PVC membranes. The electrodes showed Nernstian response to triiodide ion over the activity range from 1.0 × 10-5 to 1.0 × 10-1 mol‚L-1 with detection limits at ∼1.0 × 10-6 mol‚L-1. The resulting electrodes have fast response times (20-30 s) and good stabilities (4 months) and can be used over a wide pH range of 2.5-9.0. The proposed electrodes exhibit anti-Hofmeister behavior with excellent selectivity toward triiodide ion against a wide range of common interferences. Comparative study suggests that amino (aza) crown ether alone or in the form of a charge-transfer complex with iodine, as an ionophore in a PVC liquid membrane, is sensitive to triiodide ion. The electrodes were used as indicator electrodes in potentiometric titration of triiodide ion against thiosulfate ion.
Chinese Chemical Letters, 2011
A PVC membrane electrode based on copper(II) bis(N-2-bromophenylsalicyldenaminato) as ionophor was prepared. The ion selective electrode was tested by inorganic anions and showed a good selectivity for iodide ion. This sensor exhibited Nernstian behavior with a slope of À57.8 mV per decade at 25 8C. The proposed electrode showed a linear range from 1.0 Â 10 À5 to 1.0 Â 10 À1 mol/L with a detection limit of 5.0 Â 10 À6 mol/L. The electrode response was independent of pH in the range of 3.0-10.0. The proposed sensor was applied to determine the iodide in water and antiseptic samples.
electroanalysis, 2016
1Introduction Iodide is necessary for human health as it guarantees the proper thyroid gland function and it is used as antiseptic for skin wounds.I odidea lso exists in food, drug compound and in drinking water and it is added to table salts as as upply of iodine to prevent iodine shortage disorders [1].I na ddition, it is used as catalyst or stabilizer in polymer production and as purifying agent of drinking and swimming pool waters. Therefore,d etermination of iodide in the field of food, biological, and environmental samples is of vital importance.F or this purpose,m any methods have been developed, among of them potentio-metric basedi on selective electrode methodw hich offers speed determination, ease of preparation,f ast response time,w ide working linear range,f air selectivity,a nd low cost. Anion-selective electrodesb ased on lipophilic quater-nary ammonium or phosphonium saltse xhibit Hofmeister selectivity pattern that is basedo na nionl ipophilicity (ClO 4 À > SCN À > salicylate > I À > NO 3 À > Br À > Cl À)[ 2]. Thus,t he construction of anion potentiometric sensors based on new metal complexes which display non-Hof-meister selectivity pattern is an attractive pointo fr e-search in the field of chemical sensors.T he selectivity manner of theses ensors towards anions is found to be influenced by the steric effect related with the structure of ligandsa nd the properties of the central metal ions [2-4] where ad irect interaction occurs between the central metal of the membrane active components and the ana-lyte anion.S everal iodide selective electrodes have been reported in literature based on variousm etal complexes such as Cu 2 + [5],H g 2 + ,C d 2 + [6],T i 4 + [7],C o 3 + [8],Z n 2 + [9],C o 2 + [10],F e 3 + [11],M n 3 + [12],N i 2 + [13],a nd Fe 2 + [14] in various matrices including polyvinyl chloride and carbon paste.T ot he best of our knowledge,t here is only one published paper on the use of screen printed electrode for iodided etermination [15]. Schiff bases are condensation products of primary amines with carbonyl compounds and they were first reported by Hugo Schiffi n1 864. Schiff bases have wide applications in foodi ndustry,d ye industry,a nalytical chemistry,c atalysis,f ungicidal, agrochemical and biological activities [16].T he transition metal complexes of Schiff-bases have been foundt os how attractive properties over the other ligands such as ease of preparation, formationo fh ighly lipophilic complexes,r emarkable biological and pharmacologicala pplications and the construction of different highly selective anion and environmental sensors,e nergy storage devices and solar cells [17-20]. In this work, the synthesized Cu(II)-Schiff base complex (1) namely N-(4,6-Dimethyl-pyrimidin-2-yl)-4-[(2-hy-droxybenzylidene)amino] benzene sulfonamidec opper-(II) dihydrated complex [21] (Fig.1)w as used as iono-phore in polymeric membrane,c arbon paste,a nd screen printed electrodes.D ifferent compositions were studied, the selectivity behaviorw as examineda nd the electrodes were successfully applied for determination of iodide by Abstract:N ew poly vinyl chloride (PVC)m embrane, carbon paste (CP), and screenp rinted (SP) electrodes are constructed for iodide sensing.T hey are based on copper (II)-sulphamethazine Schiff base complex as suitable carrier. Mechanism was proved by FT-IR and UV-Vis spec-troscopy.C omputational studyi nvolvingb inding energies calculationsa tD FT/B3LYP level of theoryc onfirmed the proposed mechanism and agreed the observed selectivity pattern. Responses are near-Nernstian (À55.0, À51.0 mV/ concentration decade) for PVC,a nd SP electrodes,a nd super-Nernstian (À61.2 mV/concentration decade) for the CP electrode. Lower limit of detection (3.2 10 À6 mol L À1) and improved selectivity over the highly interfering thio-cyanate were obtainedi nc omparisonw ith the previously reported Schiff base complexes-based iodide sensors.
Analytical Sciences, 2001
Despite urgent need for a cobalt-responsive sensor for the potentiometric monitoring of Co 2+ in many industrial, clinical, pharmaceutical, plant, soil and food samples, 1 there have been only a few reports on cobalt ion-selective electrodes in the literature. 2-7 However, most of these potentiometric sensors have not been very fruitful, because the developed electrodes possess a narrow working concentration range with a near Nernstian response and relatively long response times, and suffer serious interferences from various ions, including iron, nickel, sodium, zinc, copper and cadmium. 2-7 In recent years, we have used some aza and thia-substituted crown ethers as neutral carriers in membrane transport and in PVC membrane electrode studies of some transition and heavy-metal ions. 8-11 In this paper, we report on the use of a new benzo-substituted macrocyclic diamide which was recently synthesized in our laboratories 12 as an excellent neutral carrier in the construction of a cobalt(II)-PVC membrane electrode. Experimental Reagents Reagent-grade benzyl acetate (BA), dibutyl phthalate (DBP), high relative-molecular weight PVC, oleic acid (OA), sodium tetraphenylborate (STB) and tetrahydrofurane (THF) were purchased from Merck Chemical company and used as received. 9-t-Butyl-3,9,15,21-tetraaza-4,5,13,14-dibenzo-6,12dioxabicyclo[15.3.1]henicosa-1(21),17,19-triene-2,16-dione (L) was synthesized and purified as described elsewhere. 12 Reagent-grade nitrate salts of the cations used (all from Merck) were of the highest purity available and used without any further purification, except for vacuum drying over P2O5. All other reagents were obtained from Fluka or Merck Chemical Companies and used as received. Triply distilled deionized water was used throughout.