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Abstract: Preliminary solution study shows the selectivity of di-tert-butylazodicarboxylate (TBADC) toward Fe(III) ions. Due to this selectivity, it was applied as an ionophore for construction of a Fe(III) sensor. The proposed sensor exhibits a wide linear response range with a Nerstian slope of 19.4±0.4mVdecade−1 and detection limit of 4.8×10−8 molL−1. The sensor response is pH independent in the range of 2.3–3.4 and has a fast response time of <10s. It also shows very good selectivity to Fe(III) ion over many mono-,di- and trivalent transition and heavy metal ions. The life time of the electrode was at least 10weeks. The application of the TBADC-based sensor to analysis of Fe(III) ion in a pharmaceutical formulation, and also to the monitoring of Fe(III) ion in mixtures of two, three and four different ions showed satisfactory results. [Copyright &y& Elsevier]

Based on a selective complexation of N′-(2-oxo-1,2-di(pyridin-2-yl)ethylidene)furan-2-carbohydrazide (L) with Gd(III) ions, it was used as a selectophore in construction of a Gd(III) selective PVC membrane sensor. Different compositions for the membrane were tested. The o -nitrophenyloctyl ether (NPOE) was used as suitable plasticizer, and a mixture of sodium tetraphenyl borate (NaTPB) and oleic acid (OA) as anion excluders. The proposed sensor displayed a Nernstian behavior with the slope of 19.9 ± 0.6 mV decade − 1 in concentration range of 1.0 × 10 − 6 to 1.0 × 10 − 2 mol L − 1 . Detection limit was 4.2 × 10 − 7 mol L − 1 and response time was ~ 10 s. Applicable pH range of the electrode was 4.2–8.0. Lifetime of the sensor is at least 10 weeks. Analysis of certified reference materials confirmed the accuracy of the proposed electrode. [ABSTRACT FROM AUTHOR]

Abstract: In this research, we report a new Ho3+-PVC membrane electrode based on N-(4,5-dimethyl-2-(picolinamido)phenyl)picolinamide (H2Me2bpb) as a suitable ion carrier. Poly vinylchloride (PVC)-based membrane composed of H2Me2bpb with oleic acid (OA) as anionic additives, and o-nitrophenyloctyl ether (NPOE) as plasticized solvent mediator. The sensor exhibits a Nernstian slope of 20.1±0.2mV decade−1 over the concentration range of 1.0×10−6 to 1.0×1−2 molL−1, and a detection limit of 5.0×10−7 molL−1 of Ho3+ ions. The potentiometric response of the sensor is independent of the solution pH in the range of 3.5–9.4. It has a very short response time, in the whole concentration range (<10s), and can be used for at least eight weeks. The proposed electrode shows a good selectivity towards Ho3+ ions over a wide variety of cations, including alkali, alkaline earth, transition and heavy metal ions. To assess its analytical applicability the proposed Ho3+ sensor was successfully applied as an indicator electrode in the titration of Ho3+ ion solutions in certified reference materials, alloy samples and for the determination of the fluoride ion in two mouthwash preparations. [Copyright &y& Elsevier]

Abstract: A new ion-selective electrode for Sm3+ ion is described based on the incorporation of N,N′,N″-tris(4-pyridyl)trimesic amide (TPTA) in a poly(vinylchloride) (PVC) matrix. The membrane sensor comprises nitrobenzene (NB) as a plasticizer, and oleic acid (OA) as an anionic additive. The sensor with the optimized composition shows a Nernstian potential response of 19.8±0.5mV decade−1 over a wide concentration range of 1.0×10−2 and 1×10−6 molL−1, with a lower detection limit of 4.7×10−7 molL−1 and satisfactor applicable pH range of 3.6–9.2. Having a short response time of less than 10s and a very good selectivity towards the Sm3+ over a wide variety of interfering cations (e.g. alkali, alkaline earth, transition and heavy metal ions) the sensor seemed to be a promising analytical tool for determination of the Sm3+. Hence, it was used as an indicator electrode in the potentiometric titration of samarium ion with EDTA. It was also applied to the direct samarium recovery in binary mixtures. [Copyright &y& Elsevier]

Abstract: A novel Dy(III) ion-selective PVC membrane sensor was made using a new synthesized organic compound, 3,4-diamino-N′-((pyridin-2-yl)methylene)benzohydrazide (L) as an excellent sensing element. The electrode showed a Nernstian slope of 19.8±0.6mV per decade in a wide concentration range of 1.0×10−6–1.0×10−2 molL−1, a detection limit of 5.5×10−7 molL−1, a short conditioning time, a fast response time (<10s), and high selectivity towards Dy(III) ion in contrast to other cations. The proposed sensor was successfully used as an indicator electrode in the potentiometric titration of Dy(III) ions with EDTA. The membrane sensor was also applied to the F– ion indirect determination of some mouth washing solutions and to the Dy3+ determination in binary mixtures. [Copyright &y& Elsevier]

Abstract: According to a solution study which showed a selective complexation between N,N′-bis(methylsalicylidene)-2-aminobenzylamine (MSAB) and gadolinium ions, MSAB was used as a sensing element in construction of a gadolinium(III) ion selective electrode. Acetophenon (AP) was used as solvent mediator and sodium tetraphenyl borate (NaTPB) as an anion excluder. The electrode showed a good selectivity towards Gd(III) ions over a wide variety of cations tested. The constructed sensor displayed a Nernstian behavior (19.7±0.3mV/decade) in the concentration range of 1.0×10−6 to 1.0×10−2 molL−1 with detection limit of 5.0×10−7 molL−1 and a short response time (<10s). The working pH range of the electrode was 3.5–10.1 and lifetime of the sensor was at least 10weeks. Analysis of certified reference materials confirmed the accuracy of the proposed sensor. The electrode was successfully applied as an indicator electrode in gadolinium titration with EDTA. [Copyright &y& Elsevier]

Abstract: Tests performed using heptadentate Schiff''s base ((tris(3-(thiophenal)propyl)amine (TTA)) toward Fe(III) ions indicated that it could be used as an Fe(III) selective ionophore to be used in a plasticized polymeric membrane sensor. The resulting sensors were found to produce a linear response range of five orders of magnitude with a slope of 19.8±0.3mV decade−1 with a detection limit is 8.3×10−9 molL−1. The sensor could be used in a pH window of 2.4–4.3 and the response time of the sensor was below 10s, in addition to its very good Fe(III) selectivity over many mono-,di- and trivalent transition and heavy metal ions. The life time of the electrode was found to be at least 10weeks. [Copyright &y& Elsevier]

Abstract: Conductometric study in acetonitrile solution shows the selectivity of PCQ toward europium ion. Therefore, a new europium PVC membrane electrode was prepared based on N-pyridine-2-carboxamido-8-aminoquinoline (PCQ) as an ion carrier. The electrode has a wide concentration range from 1.0×10−2 and 1.0×10−6 molL−1, Nernstian slope of 19.8±0.3mV per decade and a detection limit of 6.4×10−7 molL−1. The potentiometric response is pH independent in the range of 2.4–7.4. The proposed sensor has a relatively fast response time less than 10s and it can be used for at least 2months without any considerable divergence in its potentials. The proposed electrode revealed good selectivity toward europium ion in comparison with variety of other metal ions. The practical utility of the electrodes has been demonstrated by their use as indicator electrodes in the potentiometric titration of Eu3+ ions with EDTA and for determination of Eu3+ ion concentration in mixtures of two and three different ions. [Copyright &y& Elsevier]

Abstract: A thulium(III) membrane sensor was made using 2% sodium tetraphenyl borate (NaTPB), 65% dibutylphthalate (DBP), 30% poly(vinyl chloride) (PVC) and 3% 1-ethyl-3-(2,5-dihydro-4-(3,5-dimethyl-1H-pyrazol-4-yl)-5-oxo-1H-pyrazol-3-yl)thiourea (ET) as an ionophore. Conductometric study shows selectivity of the Et toward Tm3+ ions. Nernstian response of 19.6±0.4mV per decade of thulium concentration was observed, and the electrode worked well in concentration range of 1.0×10−6 to 1.0×10−2 mol L−1 with a lower detection limit (LDL) of 7.2×10−7 mol L−1, in a pH range of 4.3–10.4. The selectivity of the sensor over alkaline, alkaline earth, transition and heavy metal ions was also found to be in a satisfactory range. To check the analytical applicability of the proposed Tm3+ sensor, it was successfully used as an indicator electrode in analysis of thulium in certified reference materials. [Copyright &y& Elsevier]

Abstract: A new selective Nd(III) sensor has been made by using N,N′-bis(quinoline-2-carboxamido)-4,5-dimethylbenzene (H2L4) as a suitable ionophore. The sensor exhibits Nernstian response to Nd(III) ions in the concentration range of 5.0×10−6 to 1.0×10−2 M. It displays a Nernstian slope of 19.5±0.4mV/decade in the pH range of 2.9–9.2. The proposed sensor also exhibits a fast response time of

Abstract: Solution study showed N,N′-bis(5-nitrosalicylidene)-2-aminobenzylamin (L) trends toward Tb3+ ion. Then, it was used as a suitable ionophore in construction of terbium ion selective electrode. The electrode with composition of 30% PVC, 65% solvent mediator (NB), 3% ionophore (L) and 2% anionic additive (NaTPB) shows the best potentiometric response characteristics. It displays a Nernstian behavior (20.1mVdecade−1) over the concentration range 1.0×10−6 to 1.0×10−2 molL−1. The detection limit of the electrode is 6.3×10−7 molL−1. It has a very short response time (~10s) and a useful working pH range of 2.6–9.4 for at least 2months. The proposed membrane sensor shows excellent discriminating ability towards Tb3+ ions with regard to several alkali, alkaline earth, transition and heavy metal ions. To investigate the analytical applicability of the sensor, it was successfully applied to the determination of terbium in certified reference material. [ABSTRACT FROM AUTHOR]

Abstract: A new Pr3+ poly vinyl chloride PVC membrane sensor based on a membrane containing 3% N,N′-bis(4-hydroxysalicylidene)-1-3-phenylenediamine (HSPDA) as an ionophore, 2% sodium tetraphenyl borate (NaTPB) as an anionic additive, 65% benzyl acetate (BA) as solvent mediator and 30% poly(vinyl chloride) was prepared. This sensor responds to praseodymium ion in a wide linear dynamic range of 1.0×10−6 to 1.0×10−2 molL−1 with Nernstian slope of 19.8±0.4mV per decade and a detection limit of 5.7×10−7 molL−1 in pH range of 3.1 to 9.8. It has a fast response time of ~5s in the whole concentration range, and can be used for at least 2months without any considerable divergences in the potentials. The proposed sensor displays an excellent selectivity for Pr3+ ions with respect to a large number of alkali, alkaline earth, transition and heavy metal ions. The developed sensor was successfully applied as an indicator electrode in Pr3+ ion potentiometric titration with EDTA, and in direct determination of fluoride ion in two mouth wash samples. [ABSTRACT FROM AUTHOR]

Abstract: A novel Lu(III) PVC membrane sensor has been constructed based on a new synthesized symmetric S–N Schiff''s base, namely N-[(Z)-1-(2-thienyl)methylidene]-N-[4-(4-{[(Z)-1-(2-thienyl) methylidene]amino}benzyl)phenyl] amine (TBPA). The electrode showed a Nernstian slope of 19.8±0.5mV per decade across a wide concentration range of 1.0×10−6 to 1.0×10−2 molL−1 with a detection limit of 7.2×10−7 molL−1. The proposed sensor showed high selectivity toward Lu(III) ion in comparison with common alkaline, alkaline earth, transition, and heavy metals specially lanthanide ions, and could be used over a pH range of 2.7–10.6. It can be used for at least 2months without any considerable divergency in potentials and it has a relatively fast response time of <10s. The sensor was effectively used as an indicator electrode in the potentiometric titration of Lu(III) ions with EDTA. The constructed sensor accuracy was investigated by the monitoring of Lu(III) ion in mixtures of two and three different ions. [Copyright &y& Elsevier]

Abstract: In this study, a new thulium(III) membrane sensor was constructed. The proposed membrane sensor was fabricated based on a membrane containing 2% sodium tetraphenyl borate (NaTPB) as an anionic additive, 65% benzyl acetate (BA) as solvent mediator, 3% 1-(2-thiazolylazo)-2-naphthol (TN) as ionophore, and 30% poly(vinyl chloride) (PVC). The proposed Tm3+ electrode exhibits a Nernstian response of 19.5±0.2mV per decade of thulium concentration, and has a lower detection limit of 8.7×10−7 molL−1. The linear range of the sensors was 1.0×10−6 to 1.0×10−2 molL−1. It works well in the pH range of 3.2–9.5. Moreover, the recommended selective sensor revealed a comparatively satisfactory selectivity regarding most of the alkali, alkaline earth, some transition and heavy metal ions. The membrane sensor was applied to the determination of fluoride ions in mouth wash samples. [Copyright &y& Elsevier]

Abstract: In this study, a new ion-selective electrode for Ba2+ is described, illustrating 3-deoxy-d-erythro-hexos-2-ulose bis (thiosemicarbazone) (DHUT) in a poly(vinylchloride) (PVC) membrane with benzyl acetate (BA) as a plasticizer and sodium tetraphenyl borate (NaTPB) as an anionic additive. This sensor presented very good selectivity and sensitivity towards the Ba2+ ions over a wide variety of cations, including alkali, alkaline earth, transition and heavy metal ions. The electrode revealed a great improvement in the selectivity coefficients for the Ba2+ ions in comparison with the formerly reported Ba2+ sensors. The proposed electrode exhibited a significantly enhanced response towards the Ba2+ ions across the concentration range of 1.0×10−6–1.0×10−2 M for the pH variation from 2.6 to 11 with a lower detection limit of 5.6×10−7 M. Moreover, the sensors displayed the Nernstian slope of 29.6±0.5mV per decade, having a fast response time within 15s over the entire concentration range. It could also be used for at least 2months with no potential divergence. As a result, the developed sensor was successfully applied to the direct barium ion determination in solutions, rock samples and as an indicator electrode in the Ba2+ ion potentiometric titration with EDTA. [Copyright &y& Elsevier]

Abstract: The construction, performance characteristics, and application of a novel iron(III) membrane sensor based on a new bis-benzilthiocarbohydrazide (BBTC) are reported in this paper. The sensor is prepared by incorporating of BBTC, nitrobenzene (NB), and sodium tetraphenyl borate (NaTPB) into a plasticized poly(vinyl chloride) membrane. The electrode reveals a Nernstian behavior over a wide iron ion concentration range (1.0×10−2–1.0×10−7 mol L−1), and relatively low detection limit (8.6×10−8 mol L−1). The potentiometric response is independent on the pH of the solution in the range of 1.6–4.3. The electrode shows a very short response time (<10 s). The proposed electrode can be used for at least nine weeks without any considerable divergence in potentials. It exhibits very good selectivity relative to a wide variety of alkali, alkaline earth, transition and heavy metal ions. In fact, the selectivity of the proposed sensor shows great improvements compared to the previously reported electrodes for the iron ion. Also, the sensors accuracy was investigated in two ways: (i) with the potentiometric titration of a Fe(III) solution with EDTA and (ii) with the Fe(III) monitoring in river and wastewater samples. [Copyright &y& Elsevier]

Abstract: The PVC membrane containing 2,3-diphenylquinoxaline-4′,4″-dioxytriethylene glycol (PQTEG) as a suitable ionophore, presents a linear dynamic range of 1.0×10−6–1.0×10−2 M with a Nernstian slope of 29.9 mV per decade and a detection limit of 6.7×10−7 M. The response time is quick (smaller than 15 s), it can be used in the pH range of 4.1–8.9 and its duration is at least 55 days without noticing any considerable potential divergence. The proposed electrode has very good selectivity with respect to all common alkali, alkaline earth in the range of −3.28 to −4.00, and for transition metal ions in the range of −3.38 to −4.00. It was successfully applied as an indicator electrode in potentiometric titration of Sr(II) ions with EDTA. [Copyright &y& Elsevier]

Abstract: This work introduces a unique ionophore for the selective determination of Fe(III) ions. This ionophore was N-(2-hydroxyethyl)ethylenediamine-N,N′,N″-triacetic acid (NTA), presenting a high affinity towards the trivalent iron cations. The designed sensor exhibited a wide linear response with a slope of 19.5±0.4 mV per decade over the concentration range of 1.0×10−9–1.0×10−2 mol L−1, while the illustrated detection limit was 3.0×10−10 mol L−1 of the Fe(III) ions concentration. It was concluded that the sensor response was pH independent in the range of 1.8–4.5. The sensor possessed the advantages of short conditioning time, fast response time (10 s) and, especially, good selectivity towards the transition and heavy metal ions as well as some mono, di and trivalent cations. Concerning the electrode lifetime, no considerable potential divergence was noticed for at least 10 weeks. The sensor accuracy was investigated in the potentiometric titration of a Fe(III) solution with EDTA. [Copyright &y& Elsevier]

Abstract: A poly (vinyl chloride)-based membrane of N, N-Dimethyl-N′, N″-bis(4-methoxyphenyl)phosphoramidate (DMP) as a neutral carrier was prepared and investigated as a Tb3+-selective electrode. This electrode constructed with sodium tetraphenylborate (NaTPB) as the anion excluder and 2-nitrophenyl octyl ether (NPOE) as the plasticizer. Its performance was found to be the following: a Nernstian slope of 19.7±0.4 mV per decade across a broad range (1.0×10−6 to 1.0×10−1 M); a detection limit of 8.0×10−7 M between the pH values of 3.5 and 8.0; additionally, the response time was about 10 s; usage of more than 2 months without any potential divergence; good Tb3+ selectivity over a wide variety of other metal ions. The membrane sensor was applied to the Tb3+ recovery from different water samples, determination of fluoride ions in mouth wash samples and the determination of Tb3+ in phosphate rock samples. It was also used as an indicator electrode in the potentiometric titration of Tb3+ ions with EDTA. [Copyright &y& Elsevier]

Abstract: The 2-[(2-mercaptophenylimino)methyl]phenol (MPMP) was used as an excellent ionophore in the construction of a Sr2+ PVC-based membrane sensor. The best performance was obtained with a membrane composition of 30% poly(vinyl chloride), 62% nitrobenzen (NB), 5.5% MPMP and 2.5% sodium tetraphenyl borate (NaTBP). This sensor demonstrates a good selectivity and sensitivity towards the strontium ion for many cations, including alkali, alkaline earth, transition and heavy metal ions. The sensor revealed a great enhancement in selectivity coefficients for strontium ions in comparison with the previously reported strontium sensors. The proposed sensor exhibits a Nernstian behavior (with a slope of 29.6±0.3 mV per decade) for the concentration range of (1.0×10−6–1.0×10−1 M) with a detection limit of 5.5×10−7 M (48.2 ng/mL). It illustrates a relatively fast response time in the whole concentration range (<10 s) and it can be used for at least 10 weeks in a pH range of 2.8–9.6. The developed sensor was successfully used as an indicator electrode in the Sr(II) titration with EDTA and the Sr2+ ion recovery from binary mixtures. [Copyright &y& Elsevier]

Abstract: The PVC membrane, containing benzyl bisthiosemicarbazone (BTC) as a suitable ionophore, exhibited a Nernstian response for the Nd3+ ions over a wide concentration range between 1.0×10−2 and 1×10−6 M, with a detection limit of 6.2×10−7 M in the pH range of 3.7–8.3. It demonstrated a fast response time (<10s) and it could be used for at least 7 weeks without any major potential deviation. Furthermore, the electrode revealed high selectivity with respect to all the common alkali, alkaline earth, transition and heavy metal ions, including the members of the lanthanide family other than Nd3+. Concerning its applications, it was effectively employed for the determination of neodymium ions in soil and sediment samples and its validation with CRM. [Copyright &y& Elsevier]

Abstract: Highly selective and sensitive poly(vinyl chloride) (PVC) membrane electrodes based on 6-methyl-4-{[1-(2-thienyl)methylidene]amino}3-thioxo-3,4-dihydro-1,2,4-triazin-5-(2H)-one (MATDTO) as new carriers for gadolinium ion-selective electrode was reported. The membrane solutions containing PVC, o-nitrophenyl octyl ether (NPOE) as plasticizer, sodium tetraphenyl borate (NaTPB) as lipophilic ionic additive, and MATDTO, displays a calibration response for Gd3+ ions over a wide concentration range of 1.0×10−6–1.0×10−1 M with Nernstian slopes of 19.8±0.2mV per decade and a detection limit as 5.8×10−7 M. The sensor has a relatively fast response time of <10s and can be used in the pH range 3.2–8.7 for at least 2 months without any significant divergence in potentials. The selectivity coefficients for mono-, di-, and trivalent cations indicate good selectivity for Gd(III) ions over a large number of interfering cations. The membrane sensor was used as an indicator electrode in the potentiometric titration of Gd(III) ions with EDTA. The proposed electrode was also applied to the determination of concentration of Gd(III) ions in soil and sediment samples and validation with CRMs. [Copyright &y& Elsevier]

Abstract: A highly Ce(III) ion-selective poly vinyl chloride (PVC) membrane sensor based on N′-[(2-hydroxyphenyl)methylidene]-2-furohydrazide (NHMF) as an excellent sensing material is successfully developed. The electrode shows a good selectivity for Ce(III) ions with respect to most common cations including alkali, alkaline earth, transition and heavy metal ions. The proposed sensor exhibits a wide linear response with a slope of 19.4±0.3mV/decade over the concentration range of 1.0×10−5 to 1.0×10−1 M, and a detection limit of 7.6×10−6 M of Ce(III) ions. The sensor response is independent of pH in the range of 3.5–10.0. The proposed electrode was applied as an indicator electrode in potentiometric titration of Ce(III) ions with EDTA and C2O4 2. It was also successfully applied in the determination of cerium ions in aqueous samples. [Copyright &y& Elsevier]

Abstract: A poly vinyl chloride membrane sensor for chromium(III) ions was prepared based on 4-amino-3-hydrazino-6-methyl-1,2,4-triazin-5-one (AHMTO) as a membrane carrier. The sensor has a linear dynamic range of 1.0×10−6 to 1.0×10−1 M, with a Nernstian slope of 19.7±0.3mV decade−1, and a detection limit of 5.8×10−7 M. It has a fast response time of <10s and can be used for at least 3 months without any considerable divergences in its potentials. The proposed sensor revealed comparatively good selectivity with respect to most alkali, alkaline earth, some transition and heavy metal ions, and could be used in a pH range of 2.7–6.6. It was successfully used as an indicator electrode in potentiometric titration of Cr(III) with EDTA and also to the determination of Cr(III) in wastewaters of chromium electroplating industries. [Copyright &y& Elsevier]

Abstract: A highly selective membrane electrode based on nickel(II)-1,4,8,11,15,18,22,25-octabutoxyphthalocyanine (NOBP) is presented. The proposed electrode shows very good selectivity for thiocyanate ions over a wide variety of common inorganic and organic anions. The sensor displays a near Nernstian slope of −58.7±0.6mV per decade. The working concentration range of the electrode is 1.0×10−6 to −1.0×10−1 M with a detection limit of 5.7×10−7 M (33.06ng/mL). The response time of the sensor in whole concentration ranges is very short (<10s). The response of the sensor is independent on the pH range of 4.3–9.8. The best performance was obtained with a membrane composition of 30% PVC, 65% dibutyl phthalate, 3% NOBP and 2% hexadecyltrimethylammonium bromide. It was successfully applied to direct determination of thiocyanate in biological samples, and as an indicator electrode for titration of thiocyanate ions with AgNO3 solution. [Copyright &y& Elsevier]