Electrochemical Determination of Copper(II) in Water Samples Using a Novel Ion-Selective Electrode Based on a Graphite Oxide–Imprinted Polymer Composite

A novel copper(II)-selective electrode based on graphite oxide/imprinted polymer composite was developed for the electrochemical monitoring of copper(II) (Cu²⁺) ions. The electrode exhibited highly selective potentiometric response to Cu²⁺ with respect to common alkaline, alkaline earth and heavy metal cations. The composite composition studies indicated that the most suitable composite composition performing the most promising potentiometric properties was 20.0% ionophore (Cu²⁺-ion imprinted polymer), 10.0% paraffin oil, 5.0% multiwalled carbon nanotubes, and 65.0% graphite oxide. The fabricated electrode exhibited a linear response to Cu²⁺ over the concentration range of 1.0?×?10^??6–1.0?×?10^??1?M (correlation coefficient of 0.9998) with a sensitivity of 26.1?±?0.9?mV decade^??1. The detection limit of the fabricated electrode was determined to be 4.0?×?10^??7?M. The electrode worked well in the pH range of 4.0–8.0. The electrode had stable, reversible and fast potentiometric response (3?s). In addition, the electrode had a lifetime of more than 1 year. The analytical applications of the proposed electrode were performed using as an indicator electrode for the potentiometric titration of Cu²⁺ with ethylene diamine tetraacetic acid solution and for the determination of Cu²⁺ of spiked river, dam, and tap water samples. The obtained results for potentiometric titration and water samples were satisfactory.     

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.     

Ion-Selective Electrode for the Determination of Furaltadone

ABSTRACT

A Furaltadone (FD) ion-selective PVC membrane electrode based on the ion-pair complex of FD with sodium tetraphenylborate was prepared with dioctyl phthalate as a plasticiser. The electrode exhibits a linear response with an approximate Nernstian slope (50 mV decade^?1 at 20 ⁰C) with the concentration range 2.18 x 10^?5–2.18 x 10^?4 FD. The effects of ionic strength and pH of the test solution on the electrode performance were studied. The electrode exhibited very good selectivity for FD with respect to a large number of inorganic and organic cations of biological importance. The standard addition method and potentiometric titration were used to determine the FD in pure solution and in pharmaceutical preparations with satisfactory results.     

Zinc-Selective Membrane Electrode Based On 5, 6, 14, 15-Dibenzo-l, 4-Dioxa-8, 12-Diazacyclopentadecane-5, 14-Diene

ABSTRACT

A new PVC membrane for zinc ions based on DBDA15C4 as membrane carrier was prepared. The electrode shows a linear stable response over a wide concentration range (5.0 × 10^?5-1.0 × 10^?1 M) with a slope of 22 mV/decade and a limit of detection of 3.0 × 10^?5 M (2.0 μg/ml). It has a very short response time of less than 5 s and can be use for at least 11 months without any divergence in potential. The zinc ion-selective electrode exhibited very good selectivities with respect to alkali, alkaline earth and some transition and heavy metal ions and could be used in a pH range 1.5-7.0. It was successfully applied for the direct determination of zinc in a pharmaceutical sample and, as an indicator electrode, in potentiometric titration of Zn²⁺ ions.     

Bifunctional Ion‐Selective Electrode Based on C60‐Cryptand 22 for Silver and Iodine Ions

Fullerence C60‐cryptand 22 was prepared and successfully applied as the electric carrier in the PVC electrode membrane of a bifunctional ion‐selective electrode for cations, e.g., Ag⁺ ions as well as anions, e.g., I^? ions. The bifunctional ion‐selective electrode based on C60‐cryptand 22 can be applied as a Silver (Ag⁺) ion selective electrode with an internal electrode solution of 10^?3 M AgNO₃ in water (pH = 6.3), or as an Iodide (I^?) ion selective electrode with an acidic internal electrode solution of 10^?4 M KI_(aq) (pH = 2) in which the cryptand 22 is protonated, and the C60‐cryptand 22 is changed to C60‐Cryptand22–H⁺ and becomes an anionic electro‐carrier to absorb the I^? ion. The Ag⁺ ion selective electrode based on C60‐cryptand 22 gave a linear response with a near‐Nernstian slope (59.5 mV decade^?1) within the concentration range 10^?1‐10^?3 M Ag⁺_(aq). The Ag⁺ ion electrode exhibited comparatively good selectivity for silver ions, over other transition‐metal ions, alkali and alkaline earth metal ions. The Ag⁺ ion selective electrode with good stability and reproducibility was successfully used for the titration of Ag⁺_(aq) with Cl^? ions. The Iodide (I^?) Ion selective electrode based on protonated C60–cryptand22‐H⁺ also showed a linear response with a nearly Nernstian slope (58.5 mV decade^?1) within 10^?1 ‐ 10^?3 M I^? _(aq) and exhibited good selectivity for I^? ions and had small selectivity coefficients (10^?2–10^?3) for most of other anions, e.g., F^? , OH^?, CH₃COO^?, SO₄^2?, CO₃^2?, CrO₄^2?, Cr₂O₇^2? and PO₄^3? ions.     

Titration of Anionic Surfactants Using a New Potentiometric Sensor

Abstract

An anionic surfactant ion selective electrode has been developed by coating the Ru?i?ka Selectrode with plasticised polyvinyl chloride containing hyaminedodecylsulfate active substance. The electrode responds to dodecylsulfate, in the range 10^?2 ? 10^?2 mol dm^?3 and has been used for potentiometric titration of micromolar amounts of dodecylsulfate with an accuracy of 0.3%. The influence of several organic and inorganic anions has been investigated.     

Efficient Synthesis of a New Podand and Application as a Suitable Carrier for Silver Ion‐Selective Electrode

A new podand of 1,1′‐thia‐bis‐[1‐(chloroethan‐2‐acetamid‐α‐oxy)] naphtol was synthesized and used as a suitable carrier for Ag⁺ PVC membrane electrode. The electrode exhibited linear response with a Nernstian slope of (59.5±0.8 mV/decade) within a wide concentration range of 1.0×10^?7 to 1.5×10^?2 mol L^?1 silver ions. The electrode had a fast response time of <10 s and detection limit of 8.6×10^?8 mol L^?1 with a working pH range from 3.7 to 9.0. The electrode was highly selective for Ag(I) ions over a large number of cations such as alkali, alkaline earth, and heavy metal ions. The proposed sensor has been applied as an indicator electrode for indirect determination of vitamin B₁ in tablets by determination of Cl^? ions in this compound with a standard solution of Ag(NO₃).     

Zn(II)‐Selective Membrane Electrode Based on Tetraazamacrocycle [Bzo2Me2Ph2(16)hexaeneN4]

A PVC membrane electrode using [Bzo₂Me₂Ph₂(16)hexaeneN₄] ( I ) as ionophore, oleic acid as lipophilic additive and o‐nitrophenyloctyl ether as plasticizer has been investigated as Zn(II)‐selective electrode. The membrane incorporating 34.9% (w/w) PVC, 2.3% I , 4.7% OA and 58.1% o‐NPOE gave linear response over the concentration range 2.82×10^?6?1.0×10^?1 M with a Nernstian slope of 28.5±0.2 mV/decade of concentration with a detection limit of 2.24×10^?6 M (0.146 ppm) and showed a response time of less than 10 s and could be used in pH range 2.5–8.5. High selectivity was obtained over a wide variety of metal ions. The proposed electrode was successfully used as an indicator electrode in potentiometric titration of zinc ions with EDTA and for determination of zinc in real samples.     

Copper(II) Ion‐Selective Electrodes Based on Dithiosalicylic and Thiosalicylic Acids

Potentiometric carbon paste electrodes for copper(II) based on dithiosalicylic and thiosalicylic acids are described. The sensor based on dithiosalicylic acid (DTS) exhibits a linear response with a nearly Nernstian slope of 27.7 mV per decade, whereas the electrode based on thiosalicylic acid (TS) shows a super‐Nernstian slope. The limits of detection for the DTS sensor and the TS sensor are 10^?7.9and 10^?6.3 M for copper(II) activity, respectively. Selectivity coefficients are tabulated, and the influence of the pH on the response of these ISEs is studied. The DTS electrode is successfully used for potentiometric titration of humic acids with copper in order to get more information about complexing properties of these acids.     

Determination of Hg(II) ions in water samples by a novel Hg(II) sensor,based on calix[4]arene derivative

A PVC membrane electrode for Hg(II) ions, based on a new cone shaped calix[4]arene (L) as a suitable ionophore was constructed. The sensor exhibits a linear dynamic in the range of 1.0 × 10^?6–1.0 × 10^?1 M, with a Nernstian slope of 29.4 ± 0.4 mV decade^?1, and a detection limit of 4.0 × 10^?7 M. The response time is quick (less than 10 s), it can be used in the pH range of 1.5–4, and the electrode response and selectivity remained almost unchanged for about 2 months. The sensor revealed comparatively good selectivity with respect to most alkali, alkaline earth, and some transition and heavy metal ions. It was successfully employed as an indicator electrode in the potentiometric titration of Hg²⁺ ions with potassium iodide, and the direct determination of mercury content of amalgam alloy and water samples.     

Analytical Study of New Creatininium and Tetramethyl-ammonium Cation Selective Membrane Electrodes

Abstract

Two new liquid membrane electrodes which respond to creatininium and tetramethylammonium cations are described. The creatininium cation electrode exhibits rapid and near Nernstian response to creatininium cation activity, at pH 3, in the 10^?3?10^?1 mol/L range. The useful concentration range extends to 10^?4 mol/L. The tetramethyl-ammonium cation electrode exhibits rapid and near Nernstian response to tetramethylammonium cation activity, at pH 2–11.5, in the 2x10^?5? 10^?1 mol/L range. Major interferences for the creatininium electrode are Na⁺, K⁺, NH⁺ ₄ and creatine. The pK_a of the creatininium cation was calculated. A method is described for the potentiometric precipitation titration of tetramethylammonium cation with sodium tetraphenylboron. Amounts of tetramethylammonium in the range 20–200 μol have been determined using Gran's plots, with an average error of about 0.6%.     

Papaverine-Selective Plastic Membrane Electrode Based on Papaverinium Tetraphenylborate

Abstract

A plasticized PVC membrane containing the lipophilic salt papaverinium-tetraphenylborate was used to construct an ion-selective electrode for papaverine hydrochloride (Pv⁺Cl^?). The electrode shows near Nernstian response over the concentration range 1.6 × 10^?5 1.3C × 10^?2M PvCl in solutions of pH 1.0–6.2 at 25[ddot]C. The standard electrode potentials were determined at different temperatures and used to calculate the isothermal coefficient of the electrode. The electrode showed very good selectivity for Pv with respect to a large number of inorganic and organic cations. The potentiometric titration and standard addition methods were used to determine Pv in pure solutions and in pharmaceutical preparations.     

Highly Selective Potassium Ion Responsive Liquid-Membrane Electrode

Abstract

The performance of a new liquid-membrane electrode using valinomycin as membrane component is described with respect to selectivity, working range, speed of response and accuracy. The electrode makes possible the measurement of potassium ion activities in the range of 10^?1 M to at least 10^?6 M in unbuffered systems with a selectivity of potassium over sodium ions of more than 4,000. The electrode was used for the direct titration of potassium ions.     

Electroanalytical Studies of Chromone Based Ionophores for the Selective Determination of Arsenite Ion

Two chemosensors 4H‐1‐benzopyran‐3‐carboxaldehyde, 4‐oxo‐, 3‐(2‐phenylhydrazone), [I₁] and 4H‐1‐benzopyran‐3‐carboxaldehyde, 4‐oxo‐, 3‐[2‐(2,4‐dinitrophenyl)hydrazone], [I₂] with hydrazone‐NH group as binding site have been shown excellent selectivity for arsenite ion. It is confirmed by the UV‐vis titration that I₂ is more selective than I₁. The performance of the coated graphite electrode (CGE) was found to be better than polymeric membrane electrode (PME) in terms of linear range of 4.89×10^?7–1.0×10^?1 mol L^?1, low detection limit of 8.31×10^?8 mol L^?1 and short response time. The proposed sensors were also used to determine the arsenite ion in different water samples.     

Highly Sensitive Membrane Electrode Based on a Copper(II)-bis(N-4-Methylphenyl-Salicyldenaminato) Complex for the Determination of Chromate

A highly sensitive polyvinyl chloride (PVC) membrane electrode, based on copper(II)-bis(N-4-methylphenyl-salicyldenaminato) complex, (CuL₂), as a carrier was reported for the determination of chromate ion. The influence of membrane composition, pH, and possible interfering anions on the response of the ion selective electrode was investigated. The sensor exhibited a Nernstian slope of 29.7 mV per decade when the chromate concentration was varied between 2.0 × 10^?7–1.50 × 10^?2 M in a wide pH range (6.0 to 9.0). The detection limit of the ion selective electrode was 9.2 × 10^?8 M. The proposed sensor was used for at least 4 months without any considerable divergence in potential. It was applied as indicator electrode in potentiometric titration of chromate ion with Pb²⁺ and Tl⁺.     

Preparation of PbS Nanoparticles by Phase-Transfer Method and Application to Pb2+-Selective Electrode Based on PVC Membrane

Abstract

A novel approach to prepare homogeneous PbS nanoparticles by phase-transfer method was developed. The preparatory conditions were studied in detail, and the nanoparticles were characterized by transmission electron microscopy (TEM) and UV-vis spectroscopy. Then a novel lead ion-selective electrode of polyvinyl chloride (PVC) membrane based on these lead sulfide nanoparticles was prepared, and the optimum ratio of components in the membrane was determined. The results indicated that the sensor exhibited a wide concentration range of 1.0 × 10^?5 to 1.0 × 10^?2 mol·L^?1. The response time of the electrode was about 10 s, and the optimal pH in which the electrode could be used was from 3.0 to 7.0. Selectivity coefficients indicated that the electrode was selective to the primary ion over the interfering ion. The electrode can be used for at least 3 months without any divergence in potential. It was successfully applied to directly determine lead ions in solution and used as an indicator electrode in potentiometric titration of lead ions with EDTA.     

Cationic Surfactant Ion-Selective PVC Membrane Electrode Containing Macrocyclic Diimine Crown Ether

ABSTRACT

DP⁺ ion-selective PVC membrane electrode based on 2,3,11,12-dibenzo-5,9-diaza-4,9(10)-cis-diimino-1,13-dioxacyclopentadecane as a novel macrocyclic diimine crown ether is proposed. o-Nitrophenyl octyl ether as plasticizer and potassium tetrakis(4-chlorophenyl)borate as lipophilic salt were used. The electrode exhibits a Nernstian response for 1.0 x 10^?2-1.0 x 10^?6 mol 1^?1 DPCl with a slope of 58 mVdecade^?1. The detection limit is 2.5 x 10^?7 mol 1^?1. The electrode response was stable over a wide pH range (3-11). The lifetime of the electrode was about 2 months. The electrode shows a high selectivity towards inorganic cations. Among the organic cations tested, only hexadecyltrimethylammonium ion interferes. The electrode was suitable for determining the critical micelle concentration and as an end-point detector in the potentiometric titration of the cationic surfactants.     

Trace Analysis of Al (III) Ions Based on the Redox Current of a Conducting Polymer

A conducting polymer was electrochemically prepared on a Pt electrode with newly synthesized 3′‐(4‐formyl‐3‐hydroxy‐1‐phenyl)‐5,2′ : 5′,2″‐terthiophene (FHPT) in a 0.1 M TBAP/CH₂Cl₂ solution. The polymer‐modified electrode exhibited a response to proton and metal ions, especially Al(III) ions. The poly[FHPT] was characterized with cyclic voltammetry, EQCM, and applied to the analysis of trace levels of Al(III) ions. Experimental parameters affecting the response of the poly[FHPT] were investigated and optimized. Other metal ions in low concentration did not interfere with the analysis of Al(III) ions in a buffer solution at pH 7.4. The response was linear over the concentration range of 5.0×10^?8–7.0×10^?10 M, and the detection limit was 5.0×10^?10 M using the linear sweep voltammetry (LSV). Employing the differential pulse voltammetry (DPV), the response was linear over the 1.0×10^?9–5.0×10^?11 M range and the detection limit was 3.0×10^?11 M. The relative standard deviation at 5.0×10^?11 M was 7.2% (n=5) in DPV. This analytical method was successfully verified for the analysis of trace amounts of Al(III) ions in a human urine sample.     

Lead(II)-Selective Membrane Electrode Based on Tetraphenylporphyrin

ABSTRACT

A PVC membrane electrode for Pb² ions based on tetraphenylporphyrin was prepared. The sensor exhibits a Nernstian response for lead ions over a wide concentration range (1.0 x 10^?5-1.0 x 10^?2 M). The limit of detection is 8.5 x 10^?6M. It has a response time of 15 s and can be used for at least three months without any divergence in potential. The proposed electrode shows a fairly good discriminating ability towards Pb² ion in comparison to some alkali, alkaline earth, transition and heavy metal ions. The electrode can be used in the pH range 5.0 to 7.5. It was used as an indicator electrode in potentiometric titration of lead ion.     

Electrochemical Behavior of Verapamil at Graphite–Polyurethane Composite Electrodes: Determination of Release Profiles in Pharmaceutical Samples

Abstract

A solid graphite–polyurethane composite electrode has been used to determine release profiles of verapamil, a calcium-channel blocker. The electro-oxidation process was characterized by cyclic voltammetry and electrochemical impedance spectroscopy and showed no adsorption of analyte or oxidation products, unlike at other carbon-based electrodes. Quantification gave linear ranges up to 40 µmol L^?1 with cyclic voltammetry and detection limits of 0.7 µmol L^?1 by differential pulse and square-wave voltammetry. Commercial product samples were successfully analyzed with results equal to those from spectrophotometry. Because no electrode surface renewal is needed, this electrode material has many advantages.