Poly Vinyl Chloride Membrane Sensor Research Articles

New potentiometric sensor for total phenolic assay of plant extracts

Abstract In this study, a sensitive, fast, and inexpensive new potentiometric determination method based on the Folin–Ciocalteu reagent (FCR) is proposed to determine the total phenolic content in plant extracts. For this purpose, a potentiometric-based all-solid-state-contact polyvinyl chloride membrane sensor was developed. Gallic acid compound was used as the active component (ionophore) in the developed sensor and the potentiometric behavior of the sensor was characterized. The detection limit of the selective sensor to the FCR was determined as 0.022 mol L−1 and showed a linear potential change in the concentration range of 0.0039 to 0.5 mol L−1 and a fast response time of 40 to 45 s. The developed sensor was also applied to the plant extracts and the obtained measurement results were found to be in agreement with the spectrometer results in the literature.

Green electrochemical and chromatographic quantifications of the extremolyte ectoine in halophilic bacterial cultures and related pharmaceutical preparations

The realistic implementation of electrochemistry into bacterial biosynthesis monitoring programs has always been a challenging task. In this study, two simple, rapid, selective, and sensitive potentiometric sensors were developed and optimized for quantitative analysis of the extremolyte / osmoprotector ectoine (ECT) in halophilic bacterial cultures and also in its related pharmaceutical products. The developed sensors were a Polyvinyl chloride membrane sensor (ECT-PVC) and a coated graphite sensor (ECT-CG). They were established based on the ion association complex of ectoine cation with phosphotungstic acid (ECT-PTA) counter anion as ion exchange site using dioctyl-phthalate (DOP) as a solvent mediator or plasticizer. The sensors exhibited fast, stable, selective, and linear Nernstian responses over a broad range of concentrations ranging from 1 × 10−5 to 1 × 10−2 M of the studied drug. The developed sensors were optimized and cross-validated with a proposed HPLC method according to ICH guidelines. The proposed methods were successfully employed to quantify the studied drug in three different types of halophilic bacterial cultures and in an ectoine nasal spray pharmaceutical product. The selected bacteria species were Chromohalobacter salexigens, Halobacillus halophilus, and Halomonas elongata. The proposed methods were statistically compared with the reported methods, demonstrating no significant difference with respect to accuracy and precision. Greenness and environmental impact were also evaluated for the proposed procedures, verifying that they were excellent green and eco-friendly analytical methods.

A non-destructive detection method for evaluating beef taste quality based on electrochemical PVC membrane sensor

A polyvinyl chloride (PVC) membrane sensor was developed to accurately detect beef taste quality grades. The beef taste was identified by the Fisher discriminant and verified by sensory evaluation. The PVC membrane sensor with the maximum open circuit potential (OCP) value and excellent performance was composed of 0.4 mL of dibutyl phthalate (DBP), 0.25 mL of lauryl ether phosphate, 3.6 mg of magnesium stearate and 6 mg of thermoplastic polyurethanes (TPU). Texture analyzer tests showed that the membranes showed desired physical properties, and the elasticity, viscosity and cohesion of the PVC membrane sensor were 4.74 mm, 2.17 mJ and 1.89 respectively. Scanning electron microscopy (SEM) showed the electrode immersed for 6 h without separation with PVC membrane. The coefficient of variation was less than 10% with a storage period of 7 months. Sensory evaluation showed that the beef sensory rated grades array determination by the Fisher discriminant method to verify the sensitivity of ammonia-sensitive substance-modified PVC membrane sensor had an accuracy of 93.3%.

Molecular docking of different ionophores host-guest inclusion complexes for electrochemical determination of solifenacin succinate in pure and pharmaceutical dosage form: Computer aided design

The work was especially focused on confirming a brilliant connection of molecular modeling application as a modern computational chemistry and practical application to design, develop and characterize electrochemical sensors for determination of drugs. Here, for the first time, three modified polyvinyl chloride membrane sensors were developed for the electrochemical determination of solifenacin succinate in pure and pharmaceutical dosage form. These sensors were modified using alpha (α), beta (β) and gamma (γ) cyclodextrin (CD) ionophores and each membrane contained dioctyl phthalate as a plasticizer. The α, β and γ-modified sensors showed stable and rapid near-Nernstian responses of 48.92, 57.05 and 52.37, respectively, over a solifenacin concentration range of (1 × 10−2–5 × 10−5 mol L−1) and a limit of detection 2.5 × 10−5, 7.9 × 10−6 and 3.9 × 10−5 mol L−1, respectively. Molecular modeling and docking techniques were used to study the nature of the binding between the drug and ionophore molecules. Also, to assist the interpretation of the obtained results and to compare the performance of different sensors. The proposed electrodes were successfully applied for its determination in the pharmaceutical dosage form.

A novel silver(I)-selective PVC membrane sensor and its potentiometricapplications

Silver(I)-selective sensors were prepared from a solid-state contact polyvinyl chloride (PVC) membrane. ($Z)$-2-(2-((3-(2-hydroxyphenyl)-5-(p-tolyl)-1$H$-pyrrol-2-yl)imino)-5-(p-tolyl)-2$H$-pyrrol-3-yl)phenol was synthesized as an ionophore molecule and embedded in the silver(I)-selective PVC membrane composition. The optimum membrane composition was determined as 2.5% ionophore, 61.7% bis-(2-ethylhexyl)sebacate, 1.0% potassium tetrakis (p-chlorophenyl) borate, and 34.8% PVC. The developed sensor exhibited a linear potential change $E$ = 67.42 (-log [Ag$^{+}$]) $+$ 1152.9 and $R^{2}$ = 0.9960) in the varying concentration range of 1.0 $\times $ 10$^{-1}$ to 1.0 $\times $ 10$^{-5}$ mol L$^{-1}$ silver ions. This sensor shows a detection limit of 7.3 $\times $ 10$^{-7}$ mol L$^{-1}$. The proposed sensor showed a good potential change with high sensitivity even in a wide range of pH values (2.0-11.0). The proposed sensor had a quick electrochemical response of less than 3 s with good selectivity and repeatability. The sensor was also successfully applied in the analysis of real water samples. In real water samples prepared by standard addition method, recoveries in the range of 82.30%-95.15% were obtained.

Graphene nanoplatelets in potentiometry: A nanocomposite carbon paste and PVC based membrane sensors for analysis of Vilazodone HCl in plasma and milk samples

Graphene is the ''new star'' material for electrochemical sensing. It has unique mechanical, thermal and electrical properties, in addition to its ultra light weight. In the present work we combine for the first time the special features offered by graphene and the advantages of ion selective potentiometric sensors in a single study. We propose two types of sensors, a graphene based carbon paste and a poly vinyl chloride (PVC) based membrane sensors for the analysis of Vilazodone hydrochloride in bulk, human plasma and formula milk samples. Electro active agent is an ion- association complex based on coupling of Vilazodone cationic cite with anionic cite of Molybdate ion in a ratio 1:1. Both sensors are evaluated according to the IUPAC recommendation data, revealing linear response in the concentration range 10−7 − 10−3 and10−8 − 10−3 M with a Nernestian slope 59.89 and 59.91 mV/decade for PVC membrane and Carbon paste sensors, respectively. Both sensors were successfully applied to the analysis of Vilazodone HCl in human plasma and formula milk samples showing good recovery percentage values. Graphene based carbon paste sensor shows several advantages over conventional PVC membrane sensor regarding lower limit of detection, faster response time, longer life time and higher selectivity towards target ion.

Cd (II) Ion-Selective Electrode Based on 2 –Acetylthiophene Semicarbazone in Polymeric Membrane

A new polyvinylchloride membrane sensor for Cd+2 ions has been prepared using 2–acetylthiophene Semicarbazone ligand as an electroactive ionophore and dibutylphthalate (DBP) as a plasticizing agent. The best performance was recorded with a membrane composition of PVC: DBP: Ionophore: NaTPB as 31: 64: 3.2: 1.8 (w/w %).The sensor exhibits a Nernstian response for Cd+2 ions over a wide concentration range (1.0 ×10–5 to 1.0 ×10–1 M) with a slope of 29.4 ± 0.2 mV decade–1. It has a fast response time of ˂ 10 s and can be used for at least 5 weeks without any divergence in potential. The electrode can be used in the pH range from 3.4 to 7.6. The proposed sensorrevealed relatively good selectivity and high sensitivity for Cd+2 ions in presence of a number of mono, di andtrivalent interfering cations within the working range of the electrode. The electrode was successfully applied for the direct determination of Cd+2in solution and, as an indicator electrode, in potentiometric titration of cadmium ions using ethylenediamine tetraacetic acid (EDTA) as titrant. Keywords: Ion Selective Electrodes, Cadmium, PVC membrane, semicarbazide

Solid contact Zn2+ -selective electrode with low detection limit and stable and reversible potential

Abstract A new solid contact Zn2+ polyvinylchloride membrane sensor with 2-(2-Hydroxy-1-naphthylazo)-1,3,4 -thiadiazole as an ionophore has been prepared. For the electrode construction, ionic liquids, alkylmethylimidazolium chlorides are used as transducer media and as a lipophilic ionic membrane component. The addition of ionic liquid to the membrane phase was found to reduce membrane resistance and determine the potential of an internal reference Ag/AgCl electrode. The electrode with the membrane composition: ionophore: PVC: o-NPOE: ionic liquid in the percentage ratio of (wt.) 1:30:66:3, respectively, exhibited the best performance, having a slope of 29.8 mV decade−1 in the concentration range 3×10−7–1×10−1 M. The detection limit is 6.9×10−8 M. It has a fast response time of 5–7 s and exhibits stable and reproducible potential. It has a fast response time of 5–7 s and exhibits stable and reproducible potential, which does not depend on pH in the range 3.8–8.0. The proposed sensor shows a good and satisfactory selectivity towards Zn2+ ion in comparison with other cations including alkali, alkaline earth, transition and heavy metal ions. It was successfully applied for direct determination of zinc ions in tap water and as an indicator electrode in potentiometric titration of Zn2+ ions with EDTA.

The use of calixarene as ionophores in potentiometric ion-selective electrodes of naftidrofuryl oxalate using microsized membrane sensors for kinetic study of naftidrofuryl (NFT) degradation

Novel miniaturized polyvinyl chloride membrane sensors in all-solid state graphite and platinum wire supports were developed, electrochemically evaluated and used for the assay of naftidrofuryl oxalate. The naftidrofuryl oxalate sensors were based on the formation of an ion-association complex between the drug cation and tetrakis -(4-chlorophenyl)borateanionic exchanger as electroactive material and sulfocalix-8-arene as ionophore dispersed in a polyvinyl chloride matrix. Linear responses of 10 -2 -10 -6 M and 10 -2 -10 -5 M with cationic slopes of 56.9 mV and 54.1 mV over the pH range 2-5 were obtained by using the naftidrofuryl oxalate-coated graphite (Sensor 1) and platinum wire (Sensor 2) membrane sensors, respectively. The utility of 4-sulfocalix-8-arene as ionophore had a significant influence on increasing the membrane sensitivity and selectivity. The methods were also used to determine the intact drug in the presence of it’s degradate in Praxilene ® tablets, plasma and cerebrospinal fluid with good recovery. Sensor 1 was used to study the kinetics of naftidrofuryl oxalate alkaline degradation that was found to follow a pseudo first-order reaction. The activation energy could be estimated from the Arrhenius plot to be 12.572 Kcal/mol.

New lead-sensitive ion selective electrode with low detection limit

A new polyvinylchloride membrane sensor for Pb 2+ with solid contact has been prepared. The electrode membrane phase contains 1-heksyl-3-methylimidazolium hexafluorophosphate (HMImPF6) as lipophilic ionic additive. The electrode shows a Nernstian response for lead ions over a wide concentration range (1x10 -8 -1x10 -1 mol L -1 ) and the slope of 28.1 mV/decade. The limit of detection is 2.3x10 -9 mol L -1 . It has a fast response time of 5-7 s and can be used more than 2 months without any divergence in potential. The proposed sensor is not pH sensitive in the range 4.0-6.9 and shows a very good discriminating ability towards Pb 2+ ion in comparison with some alkali, alkaline earth, transition and heavy metal ions. It was successfully applied as an indicator electrode in potentiometric titration of lead ions with K2CrO4 and for direct determination of Pb 2+ ions in real sample solution.

Dissolution Testing and Potentiometric Assay of Sertraline Hydrochloride in Batch and FIA Conditions

An electrochemical polyvinyl chloride membrane sensor for sertraline (Ser) was prepared based on the ion associate of sertraline with phosphotungstic acid. The sensor was fully characterized in terms of its membrane composition, life span, effect of soaking, pH, interferences, and temperature and exhibited an average Nernestian response (61.6 ± 0.9 mV/decade) in the concentration range of 1.0 × 10−2 –5.0 × 10−5 M. Sertraline was assayed potentiometrically in its pure solutions and pharmaceutical preparations using the developed electrode under batch and flow injection conditions and the recovery values ranged from 93.44–101.12%, with a relative standard deviation of 0.53–1.27%. The sensor was successfully applied to the determination of the dissolution profile study of (Ser) tablets and the results were validated by comparison with spectrophotometric assays according to the quality control unit of the tablets pharmaceutical company producers. The results obtained from the proposed electrode were statistically analyzed and compared to a reported method. No significant difference was observed regarding both accuracy and precision.

Construction of Tb3+ PVC-MembraneElectrode Based on N,N’-Bis(pyrrolylmethylene)-2-aminobenzylamine

In this work, we report as new Tb3+-PVC membrane sensor based onN,N’-bis(pyrrolylmethylene)- 2-aminobenzylamine (PMA) as a suitable ion carrier. Poly vinylchloride (PVC)-based membrane composed of PMA with oleic acid (OA) as anionic additives and acetophenone (AP) as plasticizing solvent mediators. The Tb3+sensor exhibits a Nernstian slope of 19.7±0.4 mV per decade over the concentration range of 1.0×10-5to 1.0×10-2M and a detection limit of 4.6×10-6M of Tb3+ions. The potentiometric response of the sensor is independent of the solution pH in the range of 2.9–8.1. It has a very short response time, in the whole concentration range (∼5 s). The recommended sensor revealed comparatively good selectivity with respect to most alkali, alkaline earth, some transition and heavy metal ions. It was successfully employed as an indicator electrode in the potentiometric titration of Tb(III) ions with EDTA. The electrode was also employed for the determination of the fluoride ion in two mouth wash preparations and the determination of Tb3+ions concentration in mixtures of three different ions.

A highly selective lead-sensitive electrode with solid contact based on ionic liquid

A new polyvinylchloride membrane sensor for Pb2+ with solid contact based on ionic liquid has been prepared. The electrode shows a Nernstian response for lead ions over a wide concentration range (1×10−8 to 1×10−1molL−1) and the slope of 29.8mV/decade. The limit of detection is 4.3×10−9molL−1. It has a fast response time of 5–7s and can be used for 4 months without any divergence in potential. The proposed sensor is not pH sensitive in the range 3.5–7.3 and shows a very good discriminating ability towards Pb2+ ion in comparison with some alkali, alkaline earth, transition and heavy metal ions. It was successfully applied as an indicator electrode in potentiometric titration of lead ions with K2CrO4 and for direct determination of Pb2+ ions in real sample solution.

Determination of Ytterbium(III) Ions in Soil and Sediment Samples by a New Polymeric Yb3+-PVC Membrane Sensor

A polyvinyl chloride (PVC) membrane sensor for ytterbium(III) ions was prepared, based on 2,5-bis(5-tert-butyl-benzoxazol-2-yl)thiophene (BBT) as a membrane carrier. The sensor illustrates the following characteristics: a linear dynamic range of 1.0 × 10−6 to 1.0 × 10−2 M; a Nernstian slope of 19.7 ± 0.5 mV decade−1; a detection limit of 4.4 × 10−7 M; a response time of <10 s; and use for at least 2 months without any significant potential divergence in the pH range of 3.5–8.4. Moreover, the recommended selective sensor revealed a comparatively satisfactory selectivity regarding most of the alkali and alkaline earth ions and some of the transition-metal and heavy-metal ions. In fact, it was used as an indicator electrode in the Yb(III) potentiometric titration with ethylene diamine tetra-acetic acid (EDTA) and the determination of concentration of Yb(III) ions in soil and sediment samples.

Fabrication of a Praseodymium(III) PVC-Membrane Sensor Based on N′1,N′2-Bis(2-oxo-1,2-diphenylethylidene) ethanedihydrazide

A polyvinyl chloride membrane sensor for praseodymium(III) ions was prepared based on N′1,N′2-bis(2-oxo-1,2-diphenylethylidene)ethanedihydrazide (BEH) as a membrane carrier. This electrode has a wide linear dynamic range from 1.0 × 10−6 to 1.0 × 10−2 M with a Nernstian slope of 19.6 ± 0.4 mV per decade and a low detection limit of 4.3 × 10−7 M between the pH values of 2.8 and 8.7; additionally, the response time was about 10 s and usage was 2 months without any potential divergence. Moreover, the recommended selective sensor revealed a comparatively satisfactory selectivity regarding most of the alkali and alkaline earths and some transition- and heavy-metal ions. It was employed as an indicator electrode in the potentiometric titration of Pr(III) ions with EDTA. The membrane sensor was also applied to the Pr3+ recovery from different water samples and the determination of fluoride ions in mouthwash samples.

Fabrication of an iron(III)-selective PVC membrane sensor based on a bis-bidentate Schiff base ionophore

A Fe3+ ion-selective membrane sensor was fabricated from polyvinyl chloride (PVC) matrix membrane containing bis-bidentate Schiff base (BBS) as a neutral carrier, sodium tetraphenyl borate (NaTPB) as anionic excluder, and o-nitrophenyloctyl ether (NPOE) as a plasticizing solvent mediator. The effects of the membrane composition, pH, and additive anionic influence on the response properties were investigated. The best performance was obtained with a membrane containing 32% PVC, 62.5% NPOE, 3% BBS, and 2.5% NaTPB. The electrode shows a Nernstian behavior (slope of 19.3 ± 0.6) over a very wide iron ion concentration range (1.0 × 10−7–1.0 × 10−2 M) and has a low detection limit (7.4 × 10−8 M). The potentiometric response of the sensor is independent of pH of the solution in the pH range 1.9–5.1. The proposed sensor has a very low response time (<15 s) and a good selectivity relative to a wide variety of other metal ions including common alkali, alkaline earth, heavy, and transition metal ions. The electrode can be used for at least 60 days without any considerable divergence in potentials. The proposed sensor was successfully applied as an indicator electrode for the potentiometric titration of 1.0 × 10−2 M Fe3+ ions with a 1.0 × 10−4 M EDTA and the direct determination of Fe3+ in mineral water and wastewater samples.

A fast response cadmium-selective polymeric membrane electrode based on N, N′-(4-methyl-1,2-phenylene)diquinoline-2-carboxamide as a new neutral carrier

A new polyvinylchloride membrane sensor for Cd 2+ ions based on N, N′-(4-methyl-1,2-phenylene)diquinoline-2-carboxamide (Mebqb) as a new and excellent neutral ionophore has been prepared. The sensor shows a Nernestian response for cadmium ions over a wide concentration range (1.0 × 10 −6 to 1.0 × 10 −1 M) with the determination coefficient of 0.9964 and slope of 29.9 ± 0.5 mV decade −1. The limit of detection is 8 × 10 −7 M. It has a fast response time of 3–8 s and can be used for at least 8 weeks without any divergence in potential. The electrode can be used in the pH range from 4.0 to 9.0. The proposed sensor shows a very good discriminating ability towards Cd 2+ ion in comparison to some alkali, alkaline earth, transition and heavy metal ions. It was successfully applied for the direct determination of Cd 2+in standard and real sample solutions.

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

AbstractA 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.

Highly selective and sensitive chromium(III) membrane sensors based on 4-amino-3-hydrazino-6-methyl-1,2,4-triazin-5-one as a new neutral ionophore

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 ± 0.3 mV decade −1, and a detection limit of 5.8 × 10 −7 M. It has a fast response time of <10 s 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.

Cadmium ion-selective electrode based on tetrathia-12-crown-4

A new polyvinylchloride membrane sensor for Cd 2+ ions based on tetrathia-12-crown-4 as an ionophore was prepared. The sensor exhibits a Nernstian response for cadmium ions over a wide concentration range (4.0×10 −7 to 1.0×10 −1 M) with a slope of 29±1 mV decade −1. The limit of detection is 1.0×10 −7 M (0.01 ppm). It has a fast response time of <10 s and can be used for at least 6 weeks without any divergence in potential. The electrode can be used in the pH range from 2.5 to 8.5. The proposed sensor shows fairly good discriminating ability towards Cd 2+ ion in comparison with some alkali, alkaline earth, transition and heavy metal ions. It was successfully applied for the direct determination of Cd 2+ in solution and, as an indicator electrode, in potentiometric titration of cadmium ions.