Ion-selective PVC Membrane Electrode Research Articles

Cacodylate Sensors and their Application in the Determination of Amino Acid Levels in Biological Samples.

The importance of recognizing and quantifying chemical anions/cations found in various types of samples, including environmental and biological samples, has been extensively studied. Recent findings suggest the possibility of health risks caused by organic compound dimethylarsinic acid (DMAs) rather than its inorganic arsenic metabolite. This article aims to fabricate polymeric-membrane electrochemical sensors with high sensitivity and selectivity for the cacodylic acid sodium salt dimethylarsinate (DMAs) based on silver diethyldithiocarbamate (AgDDTC) and CuIIphthalocyanine (CuPC) as novel neutral carriers and their applications. DMAs calibration relations and titrations were carried out using a potentiometric workstation equipped with a double-junction reference electrode, in conjunction with the fabricated working electrodes. Sensors revealed fast and stable anionic response with near-Nernstian slopes (-38.6 ± 0.9 and -31.5 ± 0.6 mV/decade), within concentration ranges (1.7 × 10-5 -1.0 × 10-2 and 3.0 × 10-5 -1.0 × 10-2 M) and detection limits (1.0 × 10-5 and 1.6 × 10-5 M) for AgDDTC- and CuPC-based sensors, respectively. Sensors are characterized by extended life-time, signal stability, high precision and short response times. Selectivity for the cacodylate anion over most common anions was tested for the proposed electrodes. Sensors were satisfactorily applied for DMAs quantification in biological matrices with recoveries ranging between 96.2 and 99.0%. Membrane sensors were interfaced with a flow-through system for continuous monitoring of DMAs. The sensors were tested for the assay of different amino acids based on their reaction with cacodylate, where reaction end points were monitored with the proposed electrodes using direct potentiometric determination and flow injection analysis (FIA). Potentiometric ion-selective PVC-membrane electrodes based on silver diethyldithiocarbamate (AgDDTC) and CuIIphthalothyanine (CuPC) provide adequate and reliable means for the determination of dimethylarsenate anion (cacodylate anion, DMAs). These membrane electrodes are easy to manufacture, they have the advantages of high selectivity and sensitivity, broad dynamic ranges, low detection limits, quick response times and cost effectiveness. Such properties make these sensors suitable for the assay of DMAs levels in aqueous solutions by direct potentiometry, flow injection and potentiometric titration, as well as in monitoring of the titration end points of the reactions between various amino acids and DMAs anion in aqueous solutions. Simple electrochemical membranes for dimethylarsinate (DMAs) were prepared, based on diethyldithiocarbamate (AgDDTC) and CuIIphthalocyanine (CuPC). - DMAs sensors were fabricated in two different modules: batch (for static) and flow-through (for hydrodynamic) approaches. - Levels of DMAs were determined in spiked biological samples. - AgDDTC-based sensors were successfully applied in the determination of several amino acids via potentiometric titration with DMAs.

Farmasötik İlaçta İzoprenalin Tayini İçin Potansiyometrik Sensör Geliştirilmesi

In this study, a potentiometric ion-selective electrode (ISE) was developed for the determination of isoprenaline, a pharmaceutical active substance. For this purpose, initially, IP-PM, IP-TCA, IP-TPB, IP-REY, IP-PTA ion pairs were synthesized. The synthesized ion pairs were used as the ionophore in the structure of the electrode membrane. In order to ensure membrane optimization, PVC membrane ion selective electrodes were produced in various compositions using the synthesized ion pair and the potentiometric performance characteristics of these electrodes were investigated. It was determined that the best potentiometric performance characteristics were obtained with the PVC membrane electrode in the composition of 3.0% isoprenaline-tetrafenylborate ion pair, %64.0 nitrophenyloctylether, 32.0% polyvinylchloride and %1.0 Tetrakis (4-chlorophenyl) boron potassium compound. The linear operating range of this electrode is 5.0x 10 -6 M - 1.0x 10 -1 M and the slope at the 10-fold concentration change is 45.3 mV; determination limit, 5.0x10 -6 M, pH working range, 2.6-3.6 and 5.7-7.9; response time < 5s. The electrode exhibited a reproducible potentiometric response. Isoprenaline content was determined in drug by using the isoprenaline selective electrode.

Development of a potentiometric ractopamine-selective electrode and its application

In this study, a potentiometric ion-selective electrode (ISE) was developed in order to quantifyractopamine. Ractopamine is a phenylethanolamine with s2-adrenergic agonist properties; was in fact developed for treating respiratory diseases; and is used as tocolytic, bronchodilator and heart tonic in human and veterinary medicine (1). Ion-pair of Ractopamine-Tetraphenylborate was synthesized. The synthesized ion pair was used as ionophore in the structure of electrode membranes. For membrane optimization, PVC membrane ion-selective electrodes were produced in various compositions using the synthesized ion pairs and potentiometric performance characteristics of these electrodes were investigated. It was determined that the electrode with the composition of 5% Rac-TPB+32%PVC+62.6%DBF+0.4% KTpClPB (Potassium tetrakis (4-chlorophenyl borate) demonstrated the best potentiometric performance characteristics. The linear range, slope, limit of quantification, pH range, and response time of this electrode were determined to be 1.0×10 -5 -1.0×10 -1 M, 51.0 mV/decade, 1.0×10 -5 M, 3.0-5.0, and< 5s, respectively. The electrode has demonstrated a highlyrepeatable potentiometric response. It was applied in pigswill using ractopamine selective electrode .

Highly selective solid-state sensor for iodide based on the combined use of platinum (IV) phthalocyanine and solidified pyridinium ionic liquid

Solid-state iodide-selective electrodes based on the commercial screen-printed electrodes modified with readily available low-melting ionic material (ionic liquid solidifying at room temperature), such as N-cetylpyridinium bromide, CPBr, and a specially synthesized metallo-complex, namely, platinum (IV) phthalocyanine, PctPtCl2, are obtained. For comparison, PVC-membrane ion-selective electrodes (ISE) based on the same compounds and solid-state ISEs with other solid matrices (N-cetylpyridinium chloride, 1,3-dicetylimidazolium iodide) are studied. Plasticized PVC-membrane ISEs exhibit normal selectivity corresponding to the Hofmeister series: interfering effect of large hydrophobic ions (perchlorate, dodecyl sulfate, etc.) is significant. Incorporation of PctPtCl2 metallo-complex into plasticized membranes improves selectivity to a certain extent, but not dramatically. At the same time, the CPBr-based solid-state ISEs demonstrate high selectivity toward iodide even in the presence of hydrophobic anions: the interfering effect of perchlorate and dodecyl sulfate decreases by 3 and 6 orders of magnitude, respectively. The introduction of the metallo-complex into the matrix improves selectivity even more significantly. The CPBr-PctPtCl2-based solid-state sensor demonstrates a reversible and reproducible response to iodide. The electrode function slope S = − (54 ± 1) mV/dec, Cmin = 1.9 × 10−5 M, response time is 5–10 s.

A bismuth(III) PVC membrane ion selective electrode based on 5-(3,4,5-trimethoxyphenyl)-4-amino-1,2,4-triazole-3-thiol

Abstract The construction, performance characteristics and application of a new bismuth(III) PVC membrane electrode based on 5-(3,4,5-trimethoxyphenyl)-4-amino-1,2,4-triazole-3-thiol are reported in this paper. The designed sensor exhibited a Nernstian response for Bi3+ ion ranging from 5.0 × 10−7 mol/L to 1.0 × 10−2 mol/L with a slope of 19.8 mV/decade. The operational pH range of the sensor is 3.0–6.0. The electrode shows a response time of 6 s and can be used for at least five 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. The proposed electrode could be used as an indicator electrode in potentiometric titration of Bi3+ ions with EDTA and in the determination of Bi3+ content in stomach medicine.

Response of PVC membrane ion-selective electrodes to alkylmethylimidazolium ionic liquid cations

Several alkylmethylimidazolium tetraphenylborates (Cnmim-TPB, n=2–10) were synthesized and explored as ion exchangers in plasticized PVC membranes with very attractive sensing behaviors. And then a series of ion-selective electrodes (ISEs) were prepared and their potentiometric properties were investigated. The proposed electrodes exhibited Nernstian responses to alkylmethylimidazolium-based ionic liquid cations [Cnmim]+. These electrodes were successfully applied in the determination of thermodynamic parameters of ionic liquids in aqueous solutions and in the detection of [Cnmim]+ in tap water and distilled water with satisfactory results. For the as-prepared ISEs, one special and important relationship was observed between the selectivity coefficients and the length of alkyl side chains of interfering cations [Cnmim]+. The proper understanding of this relationship should facilitate the development of new method for the determination of ionic liquids using ISEs.

Application of the Mixed-Potential Theory to the Interpretation of the Potential Response of a PVC Membrane Ion-Selective Electrode for Desipramine

The potential response of an ion-exchanger type PVC ion-selective electrode (ISE) for a drug ion, desipramine(+) (DES(+)), was analyzed by a mixed-potential (MP) theory proposed previously. The transfer of DES(+) and its analogous ions, imipramine(+) (IMP(+)) and neostigmine(+) (NEO(+)), at a micro Ο-nitrophenyl octyl ether/water interface was studied by ion-transfer voltammetry; also, the standard ion-transfer potentials (Δ(O)(W)φ(j)(o)) of the ions were then determined. The application of MP theory with the Δ(O)(W)φ(j)(o) values successfully explained the under-Nernstian response of DES(+)-ISE due to interference from IMP(+) or NEO(+). In this study, a universal method based on numerical calculations was developed for evaluating MP associated with plural interfering ions, which was impossible in the previous method based on analytical equations. Using the universal method, we could well predict the detection limit of DES(+)-ISE theoretically. The MP theory is promising for the sophisticated design of ISEs, which is not due to conventional "trial-and-error" procedures.

PVC membrane ion selective electrodes for determination of cationic surfactants

PVC membrane ion selective electrodes for determination of cationic surfactants

Development of a new copper(II) ion-selective PVC membrane electrode based on tris(2-benzimidazolylmethyl)amine

Development of a new copper(II) ion-selective PVC membrane electrode based on tris(2-benzimidazolylmethyl)amine

A New PVC Membrane Ion Selective Electrode for Determination of Cationic Surfactant in Mouthwash

AbstractA new membrane electrode was prepared, using cetylpyridinium chloride based Sn(IV) phosphate (CPC‐SnP) as the electroactive material. The electrode exhibits a linear response for the surfactant cetylpyridinium chloride (CPC) in the concentration range 5.0 × 10−3–5.0 × 10−6 mol dm−3 with a slope as a 29.1 mV/decade change in the concentration. The working pH range and the response time for the electrode are 2–6 and 30 s respectively. Selectivity coefficients for several cations were determined. The determination of CPC in mouth wash gave results that compare favorably with those obtained by the two phase titration method. This electrode has been utilized as an indicator electrode in the potentiometric titration of cationic surfactant CPC as well as in direct determination of CPC.

Thiocyanate Ion-Selective PVC Membrane Electrode

A potentiometric selective sensor based on trinuclear chromium(III) complex as a novel ionophore for the thiocyanateselective electrode is reported. The sensor displays a near Nernstian slope of 57 ± 2 mV per decade, over a wide pH range 3 - 11. The working concentration range of the electrode is 1.10-5 – 1.10-1 mol/l with a detection limit of 5.10-6 mol/l. The sensor has a response time of 20 s and can be used for at least 6 months without any considerable fluctuation of the potential. The selectivity coefficients determined at using the fixed interference method indicate a good discriminating ability towards other anions. The prepared sensor was applied as an indicator electrode in the titration of thiocyanate with Ag+.

Lead(II) ion selective electrodes with PVC membranes based on two bis-thioureas as ionophores: 1,3-bis(N′-benzoylthioureido)benzene and 1,3-bis(N′-furoylthioureido)benzene

Two PVC membrane ion selective electrodes for Pb(II) ion based on two bis-thioureas: 1,3-bis(N′-benzoylthioureido)benzene and 1,3-bis(N′-furoylthioureido)benzene as ionophores, are reported. A first membrane formulated using 1,3-bis(N′-benzoylthioureido)benzene as carrier exhibited a Nernstian response to Pb(II) over a wide concentration range (4.0 × 10 −6 to 1.0 × 10 −2 M) with a slope of 31.5 ± 1.6 mV/dec. It showed a fast response time ( t 90% = 14 s) and could be used for 10 weeks without any divergence in potentials. The membrane formulated using 1,3-bis(N′-furoylthioureido)benzene as carrier exhibited a Nernstian response in the concentration range (5.0 × 10 −6 to 1.0 × 10 −2 M), with a slope of 30.0 ± 1.3 mV/dec. Its response time was t 90% = 14 s, and it could be used for 14 weeks without any divergence in potentials. The two proposed potentiometric sensors revealed acceptable selectivities for Pb(II) over a wide variety of other metal ions and could be used in a pH range of 2.2–6.0. Both electrodes were assayed in direct potentiometric determination of lead in soils (10–30 mg/kg range) with very good performance (0.99935 correlation coefficient in the comparison against ICP-MS method).

A New Ritodrine Selective Electrode and its Pharmaceutical Application

A novel ritodrine hydrochloride ion‐selective PVC membrane electrode based on ion‐pair complex of ritodrine‐tetra phenyl borate was prepared with di-n‐butyl phosphate as a plasticizer. The influences of membrane composition, temperature, pH of the test solution and foreign ions on the electrode performance were investigated. The electrode showed a Nernstian response over a wide ritodrine concentration range (1×10−5‐ 1×10−2 M) with a slope of 59.33 mV decade−1 and was found to be very selective, precise and usable within the pH range 3‐7.5. The standard electrode potentials, E°, were determined at different temperatures and used to calculate the isothermal temperature coefficient (dE°/dT) of the electrode, which was 0.00075. The electrode was successfully used for potentiometric determination of ritodrine hydrochloride both in pure solutions and in pharmaceutical preparations.

New Copper(II) Ion-Selective Membrane Electrode Based on Erythromycin Ethyl Succinate as a Neutral Ionophore

The potentiometric response characteristics of a new copper(II) ion-selective PVC membrane electrode based on erythromycin ethyl succinate (EES) as ionophore were investigated. The electrode exhibited a Nernstian response to Cu2+ ions over the activity range of 1.5 × 10−2 to 2.0 × 10−6 mol L−1 with a limit of detection of 6.3 × 10−7 mol L−1. Stable potentials were obtained in the pH range of 5.5–6.5. The potentiometric selectivity coefficients were calculated by using fixed interference method and revealed no important interferences except for Ag+. This electrode was successfully applied as an indicator electrode in determination of copper ions in real water samples.

New Silver Ion-selective PVC Membrane and Coated-Graphite Electrodes based on a Novel Calix|4|arene Derivative

New Silver Ion-selective PVC Membrane and Coated-Graphite Electrodes based on a Novel Calix|4|arene Derivative

Application of the cobaltabisdicarbollide anion to the development of ion selective PVC membrane electrodes for tuberculosis drug analysis

The cobaltabisdicarbollide anion is used as a new material able to generate an ion-pair complex used for PVC membrane ion selective electrodes.

A New Phosphonium Calix[4]arene for Selective Anion Recognition: Synthesis and Studies in Solution and in Ion Selective Electrodes

The synthesis and characterization of a new tetra (triphenylphosphonium) p-tert-butylcalix[4]arene 2 is presented. Its interactions with anions were studied by 1H and 31P NMR and UV absorption spectrophotometry, showing the biggest interaction with ClO4 − , I− and SCN− . Anion selectivity in ion-selective PVC-membrane electrodes (ISEs) plasticized with o-NPOE containing ionophore 2 was also investigated. Compound 2 shows a potentiometric response for various anions with the following selectivity pattern: ClO4 − > SCN− > I− > Cr2O7 2 − > NO3 − > Br− > Cl− .

고 선택성 수은(II) 이온 막 센서

A new ion selective PVC membrane electrode is developed as a sensor for mercury(II) ions based on bis(benzoylacetone) propylenediimine (H 2 (BA) 2 PD) as an ionophore. The electrode shows good response characteristics and displays, a linear Emf vs. log[Hg 2+ ] response over the concentration range of 1.0×10 -6 to 1.0×10 -1 M Hg(II) with a Nemstian slope of 29.8±0.75 mV per decade and with a detection limit of 2.2×10 -7 M Hg(II) over the pH range of 2.5-11.5. Selectivity concentrations for Hg(II) relative to a number of potential interfering ions were also investigated. The sensor is highly selective for Hg(II) ions over a large number of cations with different charge. The sensor has been found to be chemically inert showing a fast response time of 60 s and was used over a period of 3 months with a good reproducibility (S = 0.27 mV). The electrode was successfully applied to determine mercury(II) in real samples with satisfactory results.

Batch and Flow‐Injection Determination of Catecholamines Using Ion Selective Electrodes

New epinephrine (EP), dopamine (DA), and L‐Dopa (LD) ion selective PVC membrane electrodes based on ion‐pairs of catecholamines with tetraphenylborate (TPhB) are prepared. In the present work, plastic membrane selective electrodes have been constructed. They are based on the incorporation of EP‐TPhB, DA‐TPhB, or LD‐TPhB ion exchangers in poly(vinylchloride) (PVC) membranes plasticized with di(2‐ethylhexyl)sebacate (DES). The electrodes show a near – Nernstian response in the concentration ranges: 1.0×10−4—1.0×10−2 mol/L (epinephrine), 5.0×10−5–1.0×10−2 mol/L (dopamine), and 5.0×10−4–1.0×10−2 mol/L (L‐Dopa). The electrodes selective for epinephrine and L‐Dopa are used as detectors in the flow injection system. The proposed methods allow determination of catecholamines in pharmaceutical preparations.

8-Hydroxyquinoline based neutral tripodal ionophore as a copper (II) selective electrode and the effect of remote substitutents on electrode properties

New PVC membrane ion selective electrodes based on 1,3,5-Tris(8-quinolinoxymethyl)-2,4,6-trimethylbenzene (MO8HQ) are reported. The basic sensing material belongs to the group of tripodal ionophores. Also their derivatives prepared by placing suitable substitutents at fifth position of 8-oxine moiety, i.e, 1,3,5-Tris(5-chloro-8-quinolinoxymethyl)-2,4,6-trimethylbenzene (5CHQ), 1,3,5-Tris(5-benzoyl-8-quinolinoxymethyl)-2,4,6-trimethylbenzene (5BHQ) and 1,3,5-Tris[(5-phenylhydroxymethylene)-8-quinolinoxymethyl]-2,4,6-trimethylbenzene (HYD-8HQ) ionophores have also been used to make copper-selective membrane electrodes. Among all the four electrodes, MO8HQ and HYD-8HQ ionophores based electrodes show excellent response towards Cu (II) ions. The electrodes having composition 33% PVC, 4% MO8HQ and 63% dibutyl phthalate (DBP) and 33% PVC, 6% HYD-8HQ, 63% dibutyl phthalate (DBP) exhibit a good Nernstian response to Cu (II) ions in the range of 1.0 × 10 −6 to 1 × 10 −1 M. The electrode shows a reasonably fast response time of 15 s. The effect of pH and electrode response is also reported. It shows good selectivity for Cu (II) ions in comparison to heavy metal ions, transition metal ions and for alkali and alkaline earth metal ions. The electrode response and selectivity remains unchanged for at least 5 months. The electrode can be used as an indicator electrode in the potentiometric titration of Cu (II) ions with EDTA.