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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: 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: 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]

Based on the former experience on the design and construction of metal ions sensors, especially those of high sensitivity for lanthanides, (2-oxo-1,2-diphenylethylidene)-N-phenylhydrazinecarbothioamide (PHCT) was used to construct a Lu3+ PVC sensor exhibiting a Nernstian slope of 19.8±0.3 mV dec-1. The sensor was found to function well over a concentration range of 1.0x10-2 and 1.0x10-6 mol L-1 of the target ion with a detection limit of 6.8x10-7 mol L-1. The sensor selectivity against many common alkaline, alkaline earth, transition, heavy metals and specially lanthanide ions was very good and it functioned well in the pH range 2.5-8.7. Having a lifetime of at least 2 months and a short response time of ≈ 5 s, the sensor was successfully used as an indicator electrode in the potentiometric titration of Lu3+. [ABSTRACT FROM AUTHOR]

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: 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]

2,5-Dioxo-4-imidazolidinyl was used as an excellent sensing material in the preparation of a PVC membrane for a Ce(III)-selective sensor. The electrode shows a good selectivity for the Ce(III) ion with respect to most common cations including alkali, alkaline earth, transition, and heavy metal ions. The developed sensor exhibits a wide linear response with a slope of 19.6 ± 0.3 mV per decade over the concentration range of 1.0 × 10-6 to 1.0 × 10-1 M, while the illustrated detection limit is 5.7 × 10-7 M of Ce(III) ions. Moreover, it is concluded that the sensor response is pH-independent in the range of 3.1-9.8. The applications of the recommended electrode include the determination of concentration of Ce(III) ions in soil and sediment samples, validation with CRM's, and the Ce(III) ion potentiometric titration with EDTA as an indicator electrode. [ABSTRACT FROM AUTHOR]

2,5-Dioxo-4-imidazolidinyl was used as an excellent sensing material in the preparation of a PVC membrane for a Ce(III)-selective sensor. The electrode shows a good selectivity for the Ce(III) ion with respect to most common cations including alkali, alkaline earth, transition, and heavy metal ions. The developed sensor exhibits a wide linear response with a slope of 19.6 ± 0.3 mV per decade over the concentration range of 1.0 × 10-6 to 1.0 × 10-1 M, while the illustrated detection limit is 5.7 × 10-7 M of Ce(III) ions. Moreover, it is concluded that the sensor response is pH-independent in the range of 3.1-9.8. The applications of the recommended electrode include the determination of concentration of Ce(III) ions in soil and sediment samples, validation with CRM's, and the Ce(III) ion potentiometric titration with EDTA as an indicator electrode. [ABSTRACT FROM AUTHOR]

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]

• Superwetting exhibited when EGFP was applied on roughened PVC coated with GO immediately. • After substrate was stored for 3 h and used, superwetting was lost with the contact angle at 54°. • The average radius spread according to a power-law relationship, and at a faster rate with higher relative humidity. • EGFP deposition was ring-like due to pinning around the islands of GO accumulation. • 20 μL water drop in sealed 240-mL container kept relative humidity at 80 % for 150 min. The use of superhydrophilic surfaces for superwetting applications can be hampered by their wetting degradation over time. In this work, superhydrophilic surfaces were fabricated by graphene oxide (GO) deposition on roughened polyvinyl chloride (PVC) substrates. These surfaces were found to exhibit zero contact angle when enhanced green fluorescent protein (EGFP) was deposited on the surface immediately after GO was applied. However, when the GO-coated substrate was stored for 3 h, the surface displayed a contact angle of 54°. The main contact line spreading of the EGFP drop was more easily discernible using normal (500 lx, low glare and shadow free) lighting than with blue LED lighting in the dark. The average radius of the spreading main contact line was found to follow a power-law relationship that increased at a faster rate with higher relative humidity. Confocal imaging revealed rings of EGFP deposition following superwetting that is attributable to pinning around the islands of GO accumulation. Substrate superhydrophilic and superwetting properties can be preserved by adequate control of relative humidity. Relative humidity of 80 % was easily maintained for 150 min by incorporating a 20 μL water drop in a sealed 240-mL container. [ABSTRACT FROM AUTHOR]