Novel Gadolinium PVC‐Based Membrane Sensor Based on Omeprazole as an Antibiotic

A novel gadolinium ion‐selective electrode based on the antibiotic omeprazole as membrane carrier was prepared. The electrode has a linear dynamic range between 1.0×10^?1 and 1.0×10^?5 M, with a Nernstian slope of 19.3 ± 0.3 mV decade^?1 and a detection limit of 5.0×10^?6 M. The potentiometric response is independent of the pH of the solution in the pH range 4.0–10.0. The electrode possesses the advantages of short conditioning time, fast response time and especially, very good selectivity over a large number of other cations. The electrode can be used for at least 2 months without any considerable divergence in potentials. It was used as an indicator electrode in potentiometric titration of Gd(III) ions with EDTA.     

Cobalt(II)-selective membrane electrode based on N,N′-di(thiazol-2-yl)formimidamide

A new PVC-membrane electrode for Co²⁺ ions based on N,N′-di(thiazol-2-yl)formimidamide (TF) as membrane carrier has been developed. The electrode resulted in Nernstian response (29.5?±?0.4?mV decade^?1) for Co²⁺ ion over a wide concentration range (2.5?×?10^?7 ?1.0?×?10^?1?M) with a detection limit of 6.1?×?10^?8?M. The sensor has a response time of about 10?s, and can be used for at least 2 months without observing any deviation from the Nernstain response. The electrode revealed good selectivity towards cobalt(II) ion over a wide variety of alkali, alkaline earth, transition, and heavy metal ions and could be used in the pH range 2.0–7.0. The electrode was used for determination of Co²⁺ in real samples.     

Iodide‐Selective Electrode Based on Copper Phthalocyanine

Copper phthalocyanine was used as ion carrier for preparing polymeric membrane selective sensor for detection of iodide. The electrode was prepared by incorporating the ionophore into plasticized poly(vinyl chloride) (PVC) membrane, coated on the surface of graphite electrode. This novel electrode shows high selectivity for iodide with respect to many common inorganic and organic anions. The effects of membrane composition, pH and the influence of lipophilic cationic and anionic additives and also nature of plasticizer on the response characteristics of the electrode were investigated. A calibration plot with near‐Nernestian slope for iodide was observed over a wide linear range of five decades of concentration (5×10^?6?1×10^?1 M). The electrode has a fast response time, and micro‐molar detection limit (ca. 1×10^?6 M iodide) and could be used over a wide pH range of 3.0–8.0. Application of the electrode to the potentiometric titration of iodide ion with silver nitrate is reported. This sensor is used for determination of the minute amounts of iodide in lake water samples.     

Triiodide PVC Membrane Electrode Based on a Charge‐Transfer Complex of Iodine with Ditertbutyl‐Dicyclohexyl‐18‐Crown‐6

A new triiodide ion‐selective electrode based on a charge‐transfer complex of iodine with ditertbutyl‐dicyclohexyl‐18‐crown‐6 (t‐Bu)₂DC18C6 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.     

Thiocyanate-Selective PVC Membrane Electrode Based on Copper and Nickel Complexes of Para-tolualdehydesemicarbazone as Carrier

Abstract

Copper(Cu) and nickel(Ni) complexes of para-tolualdehydesemicarbazone (pTSC) were used as carrier for an thiocyanate ion–selective electrode. The Ni(II)pTSC demonstrated higher selectivity for thiocyanate ions with better performance than Cu(II)pTSC as carrier. The electrode shows a Nernstian slope of 58.8 ± 0.3 mV decade^?1 with improved linear range of 1 × 10^?2 to 1 × 10^?7 M and a low detection limit of 1.25 × 10^?7 M in the pH range of 3–10, giving a relatively fast response and reversibility within 10 s. The selectivity coefficient was calculated using matched potential method. The electrode worked well for nearly 3 months. The response mechanism is discussed by UV-visible spectroscopic technique. The electrodes were used in potentiometric titration of thiocyanate with silver nitrate. Further, the electrode was successfully applied to determine the thiocyanate content in physiological fluids.     

Polymeric Membrane Lanthanum(III)‐Selective Electrode Based on N,N′‐Adipylbis(5‐phenylazo salicylaldehyde hydrazone)

A recently synthesized azao‐containing Schiff's base N,N′‐adipylbis(5‐phenylazo salicylaldehyde hydrazone) was used as a suitable neutral ion carrier in construction of a highly selective La³⁺‐PVC membrane electrode. The electrode exhibits a Nernstian response with a slope of 19.4 mV decade^?1 over a wide concentration range (1.0×10^?6–1.0×10^?2 M) and a limit of detection of 4.0×10^?7 M (0.05 ppm). The electrode possesses a fast response time of ca. 10 s and can be used for at least 3 months without observing any deviation. The proposed electrode revealed excellent selectivity for La³⁺ over a wide variety of alkali, alkaline earth, transition and heavy metal ions and could be used in a pH range of 4.0–8.0. The practical utility of the electrode has been demonstrated by its use as an indicator electrode in the potentiometric titration of La³⁺ ions with EDTA and in determination of F^? ion in some pharmaceutical preparations.     

Determination of lead (II) ion by highly selective and sensitive lead (II) membrane electrode based on 2-(((E)-2-((E)-1-(2-hydroxyphenyl) methyliden)hydrazono)metyl)phenol

A PVC (poly vinyl chloride) membrane electrode for lead ion based on 2-(((E)-2-((E)-1-(2-hydroxyphenyl)methyliden)hydrazono)metyl)phenol (HMHMP) as a membrane carrier was prepared. This electrode exhibited linear response with Nernstian slope of 29.2?±?0.2?mV per decade within the concentration range of 2.0?×?10^?7–1.0?×?10^?1?M lead ion. The limit of detection, as determined from the intersection of the extrapolated linear segments of the calibration plot, was 8.0?×?10^?8 M. The electrode exhibited high selectivity for Pb (II). The response time of the electrode was about 5–10?s for different concentrations. The electrode is suitable for use in aqueous solutions in a pH range of 5.0–7.5. It was used as an indicator electrode in a titration of Pb (II) with chromate at constant pH. This electrode was used for the determination of lead in ore samples, and the results were in agreement with those obtained with an atomic absorption spectroscopy (AAS) method. Also lead selective electrode was used for monitoring of lead in spiked samples of the Zayanderud River and waste water by the potentiometry technique.     

Lead Ion‐Selective Polypyrrole Solid‐Contact Electrode Based on Crown Ether

Abstract

The lead(II) ion selective solid‐contact electrode based on polypyrrole film, covered with a polyvinyl chloride membrane has been prepared. Polypyrrole film was used as a mediating layer of the solid‐contact electrode due to the conductivity. Crown ether has been used as ionophores in polyvinyl chloride cocktail solutions. This solid‐contact electrode based on benzo‐15‐crown‐5 exhibited Nernstian‐response within 30 s response time over concentration range, 1×10^?1～5×10^?7 M. The selectivity of this electrode to other metal cations was comparatively good. This electrode showed much better results, such as detection range, slope, response time and reproducibility than conventional ion selective electrode and coated wire electrode.     

Self‐Assembled Mercapto‐Compound‐Gold‐Nanoparticle‐Modified Carbon Paste Electrode for Potentiometric Determination of Cadmium(II)

A new modified carbon paste electrode (CPE) based on a recently synthesized ligand [2‐mercapto‐5‐(3‐nitrophenyl)‐1,3,4‐thiadiazole] (MNT), self‐assembled to gold nanoparticles (GNP) as suitable carrier for Cd(II) ion with potentiometric method are described. The proposed electrode exhibits a Nernstian slope of 29.4±1.0 mV per decade for Cd(II) ion over a wide concentration range from 3.1×10^?8 to 3.1×10^?4 mol L^?1. The detection limit of electrode was 2.0×10^?8 mol L^?1 of cadmium ion. The potentiometric responses of electrode based on MNT is independent of the pH of test solution in the pH range 2.0–4.0. It has quick response with response time of about 6 s. The proposed electrode show fairly good selectivity over some alkali, alkaline earth, transition and heavy metal ions. Finally, the proposed electrode was successfully employed to detect Cd(II) ion in hair and water samples.     

A Novel Modified Carbon Paste Electrode for Potentiometric Determination of Mercury(II) Ion

A new modified carbon paste electrode (CPE) based on a recently synthesized ligand of Ethyl‐2‐(benzoylamino)‐3‐(2‐hydroxy‐4‐methoxyphenyl)‐2‐propenoate (EBHMP) as a suitable carrier for Hg²⁺ ion was described. The electrode exhibit a super Nernstian slope of 48.5±1.0 mV per decade for Hg²⁺ ion over a wide concentration range from 3.0×10^?7–3.1×10^?2 M. The lower detection limits are 1.0×10^?7 M Hg²⁺. The electrode has a fast response time (ca. 5 s), a satisfactory reproducibility and relatively long life time. The proposed sensor shows a fairly good selectivity toward Hg²⁺ ion in comparison to other common cations. The potentiometric responses are independent of the pH of the test solution in the pH range 1.0–4.0. The proposed electrode was used as an indicator electrode in potentiometric titration of mercuric ion with standard solution of EDTA. The direct determination of mercury in spiked wastewater and an amalgam sample gave results that compare favorably with those obtained by the cold vapor atomic absorption spectrometric method.     

Highly Thiocyanate‐Selective PVC Membrane Electrode Based on Lipophilic Ferrocene Derivative

A novel anion‐selective PVC membrane electrode based on bis‐[(3‐ferrocenyl)‐(2‐crotonic acid)] copper(II) complex [Cu(II)‐BFCA] as neutral carrier is described, which demonstrates excellent potentiometric response characteristics toward thiocyanate ion and anti‐Hofmeister selectivity sequence in following order: SCN^?>I^?>ClO >Sal^?>Br^?>NO >Cl^?≈NO >SO >SO . The electrode shows a near‐Nernstian response for thiocyanate ion in a wide range of 9.0×10^?7–1.0×10^?1 M with a detection limit 6.8×10^?7 M and a slope of ?59.1 mV/decade in pH 5.0 of phosphate buffer solution at 20 °C. The influences of lipophilic cationic and anionic additives on the response properties of the electrode were investigated. High sensitivity and wide linear dynamic range were observed for the electrode in the presence of hexadecyltrimethylammoniumborate (HTAB) as a lipophilic cationic additive. The electrode was successfully applied to the determination of thiocyanate ion in waste water and human saliva.     

Highly Selective and Sensitive Triiodide PVC‐Membrane Electrode Based on a New Charge‐Transfer Complex of Bis(2,4‐Dimethoxybenzaldehyde)butane‐2,3‐Dihydrazone with Iodine

In this work, a highly selective membrane triiodide sensor based on a new charge‐transfer complex of bis(2,4‐dimethoxybenzaldehyde)butane‐2,3‐dihydrazone with iodine (Iodide Charge Transfer complex: ICT) as membrane carrier is introduced. The influences of five different solvent mediators on sensitivity and selectivity of the proposed sensor were considered. The best performance was obtained with the membrane composition containing 30% poly (vinyl chloride), 63% DBP, 5% ICT and 2% HTAB. The electrode shows a Nernstian behavior over a very wide triiodide ion concentration range (1.0 × 10^?7‐1.0 × 10^?2 M), and a detection limit value of 8.0 × 10^?8 M. The effect of pH on the potentiometric response of the sensor was also studied, and it was found that the response of the electrode is independent of the pH of the solution in the pH range of 4.0–10. The proposed sensor has a very fast response time (< 12 s), and good selectivities relative to a wide variety of common inorganic and organic anions, including iodide, acetate, bromide, chloride, fluoride, nitrite, nitrate, sulfite, sulfate, cyanide and thiocyanate. In fact the selectivity behavior of the proposed triiodide ion‐selective electrode shows great improvements compared to the previously reported electrodes for triiodide ion. The proposed membrane sensor can be used for at least 6 months without any divergence in the potentials. The electrode was successfully applied as an indicator electrode in the titration of triiodide with thiosulfate ion.     

Application of Tetra Cyclohexyl Tin(IV) as an Anionic Carrier for the Construction of a New Salicylate Membrane Sensor

A new tin complex namely tetracyclohexyl tin(IV) (TCHT) was synthesized and used as the ion carrier for the construction of a highly selective salicylate sensor. This sensor shows a Nernstian response to salicylate ions over a very wide concentration (1.0 × 10^?7–1.0 × 10^?1 M) in a pH range of 5.5–10.5. The optimum selectivity and response could be obtained for a membrane incorporating 30% PVC, 61% BA, 3% of cationic additive (HTAB) and 6% of TCHT. The response time of the electrode is very short in the whole concentration range (15 s). The electrode also shows an excellent discriminating ability for salicylate ions with respect to the most common organic and inorganic anions including chloride, sulfate, nitrate, nitrite, cyanide, sulfite, iodide, thiocyanate, phosphate, acetate, oxalate, citrate, and tartarate ions. The detection limit of the proposed sensor is 8.0 × 10^?8 M. The electrode was successfully used for determining the concentration of salicylate ion in synthetic serums.     

Novel Copper(II)‐Selective Membrane Electrode Based on a New Synthesized Schiff Base

A PVC membrane electrode for copper(II) ion based on a recently synthesized Schiff base as a suitable ion carrier was constructed. The electrode exhibits a Nernstian slope of 28.3 ± 0.6 mV per decade of Cu²⁺ over a wide concentration range of 7.0 × 10^?6‐2.6 × 10^?2 M with a detection limit of 5.0 × 10^?6M in the pH range of 4.2–5.8. The response time is about 10s and it can be used for at least 1 month without any considerable divergence in potential. It was successfully applied as an indicator electrode in the potentiometric titration of copper ions.     

Highly Selective and Sensitive Triiodide PVC‐Based Membrane Electrode Based on a New Charge Transfer Complex of 2‐(((2‐(((E)‐1‐(2‐Hydroxyphenyl) Methylidine) Amino) Phenyl) Imino) Methyl) Phenol for Nano‐Level Monitoring of Triiodide

Abstract

A highly selective and sensitive triiodide sensor based on a 2‐(((2‐(((E)‐1‐(2‐hydroxy phenyl) methylidine) amino) phenyl) imino) methyl) phenol with iodine (CTC) as membrane carrier was developed. The electrode revealed a Nernstian behavior over a very wide triiodide‐ion concentration range (5.0×10^?8–1.0×10^?2 M), and relatively low detection limit (3.0×10^?8 M). The potentiometric response is independent of the pH of solution in the pH range of 3.0–10.0. The electrodes manifest advantages of low resistance, very fast response (<12 s), and most importantly, good selectivities relative to a wide variety of inorganic and organic anions, including iodide, bromide, chloride, fluoride, sulfite, sulfate, cyanide, thiocyanate, and acetate. In fact, the selectivity behavior of the proposed triiodide ion‐selective electrode shows great improvements compared to the previously reported electrodes for the triiodide ion. The proposed membrane sensor can be used for at least 6 months without any significant divergences in the potential. The electrode was successfully applied as an indicator electrode in the titration of triiodide with thiosulfate ion.     

Ketoconazol‐Triiodide Ion Pair Complex as a Suitable Carrier in an Iodide Selective Membrane Electrode

A novel membrane sensor for selective monitoring of iodide, consisting of a triiodide‐ketoconazole ion pair complex dispersed in a PVC matrix, plasticized with a mixture of 2‐nitrophenyl octyl ether and dioctylphtalate with unique selectivity toward iodide ions, is described. The influence of membrane composition, pH of test solution and foreign ions on the electrode performance were investigated. The optimized membrane demonstrates a near‐Nernstian response for iodide ions over a wide linear range from 1.0 × 10^?2 to 1.0 × 10^?5 M, at 25 ± 1 °C. The electrode could be used over a wide pH range 3–10 and has the advantages of high selectivity, fast response time and good lifetime (over 4 months). It was successfully used as indicator electrode in potentiometric titrations and direct potentiometric assay of iodide ions.     

Solid-state ion selective electrode based on polypyrrole conducting polymer nanofilm as a new potentiometric sensor for Zn2+ ion

A pencil graphite electrode (PGE) electrodeposited by a polypyrrole conducting polymer doped with tartrazine (termed as PGE/PPy/Tar) was prepared and used as a zinc (II) solid-state ion-selective electrode. For the preparation of the zinc sensor electrode, electrodeposition of a polypyrrole nanofilm was carried out potentiostatically (E _app?=?0.75 V vs SCE) in a solution containing 0.010 M pyrrole and 0.001 M tartrazine trisodium salt. A pencil graphite and Pt wire were used as working and auxiliary electrodes, respectively. The introduced electrode in the current paper can be fabricated simply and was found to possess high selectivity, exhibited wide working concentration range, sufficiently rapid response, potential stability, and very good sensitivity to Zn (II) ion. The sensor electrode showed a linear Nernstian response over the range of 1.0?×?10^?5 to 1.0?×?10^?1 M with a slope of 28.23 mV per decade change in zinc ion concentration. A detection limit of 8.0?×?10^?6 M was obtained. The optimum pH working of the electrode was found to be 5.0.     

Preparation of Cu (II) imprinted polymer electrode and its application for potentiometric and voltammetric determination of Cu (II)

The Cu (II) imprinted polymer glassy carbon electrode (GCE/Cu-IP) was prepared by electropolymerization of pyrrole at GCE in the presence of methyl red as a dopant and then imprinting by Cu²⁺ ions. This electrode was applied for potentiometric and voltammetric detection of Cu²⁺ ion. The potentiometric response of the electrode was linear within the Cu²⁺ concentration range of 3.9 × 10^?6 to 5.0 × 10^?2 M with a near-Nernstian slope of 29.0 mV decade^?1 and a detection limit of 5.0 × 10^?7 M. The electrode was also used for preconcentration anodic stripping voltammetry and results exhibited that peak currents for the incorporated copper species were dependent on the metal ion concentration in the range of 1.0 × 10^?8 to 1.0 × 10^?3 M and detection limit was 6.5 × 10^?9 M. Also the selectivity of the prepared electrode was investigated. The imprinted polymer electrode was used for the successful assay of copper in two standard reference material samples.     

Original Potentiometric Ytterbium(III) PVC-Membrane Sensor Based on N1,N2-Bis-[1-(2-hydroxy-1,2-diphenyl)ethylidene]ethanedihydrazide

Abstract

In this work, we describe the construction, performance, and applications of an original ytterbium(III) sensor based on N¹,N²-bis-[1-(2-hydroxy-1,2-diphenyl)ethylidene]ethanedihydrazide (BHDEH), which acts as a suitable carrier. Because it has a low detection limit of 4.2 × 10^?7 M, the sensor response for the Yb(III) ion is Nernstian over a wide concentration range: four decades of concentration (1.0 × 10^?6 to 1.0 × 10^?2 M). The response time of the electrode is less than 10 s, it can be used in the pH range of 3.2–8.3, and its duration is at least 2 months without any considerable potential divergence. The sensor revealed very good selectivity for Yb(III) in the presence of several metal ions. To investigate the sensor analytical applicability, it was tested as an indicator electrode in the potentiometric titration of Yb(III) solution with standard EDTA solution. The proposed electrode was also used to determine fluoride ions in mouthwash.     

A Novel Al(III)‐Selective Electrochemical Sensor Based on N,N′‐Bis(salicylidene)‐1,2‐phenylenediamine Complexes

A polyvinylchloride membrane sensor based on N,N′‐bis(salecylidene)‐1,2‐phenylenediamine (salophen) as membrane carrier was prepared and investigated as a Al³⁺‐selective electrode. The sensor exhibits a Nernstian response toward Al(III) over a wide concentration range (8.0×10^?7–3.0×10^?2 M), with a detection limit of 6.0×10^?7 M. The potentiometric response of the sensor is independent of the pH of the test solution in the pH range 3.2–4.5. The electrode possesses advantages of very fast response and high selectivity for Al³⁺ in comparison with alkali, alkaline earth and some heavy metal ions. The sensor was used as an indicator electrode, in the potentiometric titration of aluminum ion and in determination of Al³⁺ contents in drug, water and waste water samples.