Coated-wire Electrodes Research Articles

Fast chromium determination in pharmaceutical tablets by using electrochemical sensors: Preparation and comparison

In the present paper, three electrodes were prepared with the aim of detecting chromium (III) in pharmaceutical tablets and comparing their capabilities and efficiency. At first, N-(pyridine-2-ylcarbamothioyl) benzamide (NP2YCTB) was synthesized and characterized by 1H NMR, FTIR, and 13C NMR spectroscopy methods. Then, it is used as a sensing material to prepare three types of chromium potentiometry sensors including solid-state electrodes (SSE), coated wire electrodes (CWE) as asymmetric electrodes, and liquid membrane electrodes (LME) as symmetric electrodes. The responses of all electrodes were Nernstian. Field-emission scanning electron microscopy was utilized to investigate the liquid membrane morphology. The presence of chromium (III) in the membrane was proved using Energy-dispersive X-ray spectroscopy and the coordination of NP2YCTB heteroatoms with chromium (III) was confirmed by Fourier transform infrared spectroscopy. The limit of detection for SSE (3 × 10−9 mol/L) was enhanced compared with LME (7 × 10−6 mol/L) and CWE (3 × 10−7 mol/L). The response time of electrodes was very short so it was about 5–6 s for LME and CWE and 5–8 s for SSE. The sensors were used for the potentiometric determination of chromium (III) in pharmaceutical tablets and in the potentiometric titration of it with EDTA.

A new coated-wire electrode based on clopidogrel-hexathiocyanato ferrate (III) ion-pair

A new coated-wire electrode based on clopidogrel-hexathiocyanato ferrate (III) ion-pair

A Summary of Recent Developments in Potentiometric Sensor Arrays

With upgrades in as far as possible and selectivity of ISEs, the presentation of new materials, new detecting ideas (from regular potentiometric to dynamic electrochemistry draws near), and more profound hypothetical getting it and displaying of the potentiometric reactions of ISEs, potentiometric in light of particle specific cathodes (ISEs) has encountered a renaissance. Ion sensors based on solid-state or polymeric membranes are currently available and can be used in sensor array formats for a variety of analytical applications. Coated wire electrodes (CWE), ion-sensitive field-effect transistors (ISFETs), and light-addressable potentiometric sensors (LAPS) are just a few of the strategies that have been developed to construct and use potentiometric sensor arrays based on various transduction principles. This review aims to provide a critical overview of these strategies. After reading recent papers on the development and applications of potentiometric sensor arrays, several issues and trends have been identified.

Construction of a Zinc Oxide Nanorod-Modified Coated Wire Electrode for Potentiometric Determination of Levocetirizine Dihydrochloride in Its Pure and Combined Form.

Coated wire electrodes (CWEs) are considered the most effective and selective type of ion- selective electrodes because of the electroactive materials which are used in surface modification. This study aims to construct the first potentiometric method for analysis of levocetirizine (LVZ) in its combination form with montelukast (MON) drug. A novel potentiometric sensor which consists of a silver wire coated with zinc oxide (ZnO) nanorod modified with a polymeric membrane (combining β-cyclodextrin and tetraphenyl borate, and plasticized with di-butyl phthalate) was constructed for the determination of LVZ·2HCl in its pure form and its combination dosage form. The fabricated sensor exhibited a linearity range of 5 × 10-6-1 × 10-2 mol/L with a Nernstian slope 57.88 mV/decade over the pH range 2-4.5. The effect of temperature on the constructed sensor was studied and it was found that the electrode worked effectively over 10-50°C. The electrode showed a fast response time and the lifetime of the electrode was found to be 72 days without significant change in the Nernstian slope value. The selectivity of the electrode toward LVZ was estimated in the presence of some obstructive ions. The method was validated according to International Council for Harmonisation of Technical Requirments for Registration of Pharmaceuticals for Human Use (ICH) rules and applied to the determination of LVZ in its pure and combined pharmaceutical dosage forms. This article introduces the synthesis of the first coated wire electrode modified with zinc oxide (ZnO) nanorods for the determination of the drug levocetirizine. The results demonstrate the ability of electrochemical methods to analyze drugs in combination. The presented method excels over the other analytical methods in terms of sensitivity, selectivity, and simplicity.

Diltiazem-tetraiodide bismuthate (III) based PVC membrane for selective determination of diltiazem hydrochloride

A new coated-wire electrode based on PVC membrane plasticized with dioctyl phthalate (DOP) and containing the diltiazem-tetraiodido bismuthate (III) ion association coated on a silver wire was constructed and used for potentiometric determination of diltiazem hydrochloride. The electrode performance was characterized and optimized according to the following experimental criteria: membrane composition, soaking time, working pH range, and response time. The interference caused by different species was investigated as well. The best membrane composition was found to be 49.75% of PVC and DOP, 0.5% ion pair. This sensor showed a linear response with a good Nernstian slope of 57.60±1.38 mV/decade over the concentration range5.0×10-5 – 2.50×10-2 M, the detection limit was 2.88×10-5 M, and it was usable within a wide pH range of 2.5–8.0. The electrode showed a fast response time (18 sec), with a relative long lifetime (2.4 months, 2 h a day). The isothermal coefficient (dE°/dT) of the electrode was calculated and found to be 5.36×10-4 V/℃ within 20 – 80℃, which exhibits a good thermal stability. The coted-wire electrode was successfully applied for the potentiometric determination of diltiazem hydrochloride both in pure form and pharmaceutical preparations. The dissolution test of the drug was carried out as well.

Finishing the surface micro-layer of additively manufactured TiAl alloy using electro-thermal discharge assisted post-processing

Selective laser melting (SLM) of titanium–aluminium (TiAl) alloy components has gained significant attention in the modern industrial world. The flexibility of the SLM process in producing complex shapes with minimum utilization of material and energy makes it dominant over other manufacturing techniques. As aerospace and biomedical industries demand complex-shaped TiAl alloy components, part fabrication using SLM becomes the ultimate solution. However, the unacceptable level of surface integrity and anisotropic behavior of SLM components demand post processing operations such as laser polishing, chemical polishing, and conventional polishing methods. In this study, a recently developed polishing method called wire electrical discharge polishing (WEDP) is performed on TiAl alloys for obtaining a smooth and defect-free surface. This study aims to investigate the micro-layer modification occurring to the WEDP-processed surface in detail. The experimental results establish the effectiveness of WEDP method in terms of improved surface integrity. The surface finish (Sa) got enhanced by ~88% after WEDP processing. In addition, the thickness of recast layer formed by WEDP was found to be minimum. Moreover, post-processing of TiAl alloy resulted in better surface morphology specifically at lower settings of peak current. It is noteworthy that the migration of wire material was minimum with zinc-coated brass electrode compared to the normal brass electrode. Hence, coated wire electrodes are recommended for WEDP process. In short, an excellent surface integrity can be achieved using WEDP process through favorable surface modification aided by lower peak current and coated wire electrodes. Furthermore, less electrode wear observed in WEDP process enables the deployment of lower feed rates leading to minimal electrode consumption.

The Machinability Characteristics of Multidirectional CFRP Composites Using High-Performance Wire EDM Electrodes

Due to the abrasive nature of the material, the conventional machining of CFRP composites is typically characterised by high mechanical forces and poor tool life, which can have a detrimental effect on workpiece surface quality, mechanical properties, dimensional accuracy, and, ultimately, functional performance. The present paper details an experimental investigation to assess the feasibility of wire electrical discharge machining (WEDM) as an alternative for cutting multidirectional CFRP composite laminates using high-performance wire electrodes. A full factorial experimental array comprising a total of 8 tests was employed to evaluate the effect of varying ignition current (3 and 5 A), pulse-off time (8 and 10 µs), and wire type (Topas Plus D and Compeed) on material removal rate (MRR), kerf width, workpiece surface roughness, and surface damage. The Compeed wire achieved a lower MRR of up to ~40% compared with the Topas wire when operating at comparable cutting parameters, despite having a higher electrical conductivity. Statistical investigation involving analysis of variance (ANOVA) showed that the pulse-off time was the only significant factor impacting the material removal rate, with a percentage contribution ratio of 67.76%. In terms of cut accuracy and surface quality, machining with the Compeed wire resulted in marginally wider kerfs (~8%) and a higher workpiece surface roughness (~11%) compared to the Topas wire, with maximum recorded values of 374.38 µm and 27.53 µm Sa, respectively. Micrographs from scanning electron microscopy revealed the presence of considerable fibre fragments, voids, and adhered re-solidified matrix material on the machined surfaces, which was likely due to the thermal nature of the WEDM process. The research demonstrated the viability of WEDM for cutting relatively thick (9 mm) multidirectional CFRP laminates without the need for employing conductive assistive electrodes. The advanced coated wire electrodes used in combination with higher ignition current and lower pulse-off time levels resulted in an increased MRR of up to ~15 mm3/min.

Determination of Triprolidine Hydrochloride Using High Sensitivity Selective Nano-Electrode and Conventional Coated Wire Electrodes

Determination of Triprolidine Hydrochloride Using High Sensitivity Selective Nano-Electrode and Conventional Coated Wire Electrodes

The Coated-Wire Ion-Selective Electrode (CWISE) of Tartrazine Using Chitosan as an Ionophore

Research on the Ion-Selective Electrode (ISE) of coated wire-type tartrazine using chitosan as an ionophore has been developed. The variables used in the manufacture of ISE are membrane composition and immersion time. Meanwhile, the basic characteristics of ISE measured are Nernst value, measurement concentration range, detection limit, and measurement response time. The results showed that ISE tartrazine coated wire type had an optimum membrane composition in a mixture of chitosan: PVC: DOP of 3: 34: 63 (% w/w) and a membrane immersion time 20 minutes. The basic characteristics of ISE produce a Nernst value of 20.976 mV/decade. The measurement concentration range is 1×10-7-1×10-2 M with a detection limit of 2.749×10-7 M or 0.1469 ppm. The response time ranges from 10-60 seconds, with an average of 40 seconds.

A Novel Coated Wire Electrode And Coated Graphite Electrode for Potentiometric Determination of Amitriptyline Hydrochloride in its pharmaceutical preparations, urine and blood plasma

This paper uses the potentiometric method to evaluate (amitriptyline hydrochloride, AM) by creating selective electrodes for AM drugs with the active ingredient (Ammonium Reinackate, AR) using a plasticizer (Dibutyl phthalate, DBP). The results showed that for (Coated Wire Electrode (CWE)) and Coated Graphite Electrode (CGE) respectively, the Nernstian slope of the prepared Am-AR-DBP electrodes is (57.293, 58.803 mV / decade). With a pH range of (4-7) and a concentration range of 1 ?? 10 ?? Λ(-6)-1 ?? 10 ?? Λ(-1) M for both electrodes, the upper and lower limit of detection for the Am-AR-DBP CGE is 0.2042M, 4.8 ?? 10 ? Λ(-7) M, and the upper and lower limit of detection for the Am-AR-DBP CWE electrode is 0.2051M, 4.91 ?? 10Λ(-7) M, respectively. The response time ranges from 20-83 sec, 14-76 sec for CWE and CGE electrodes respectively. For the CWE electrode, the age of the electrodes is 26 days, and for the CGE electrode, 42 days. The research included calculating the selectivity with the presence of interferers of these electrodes where the K(i, j)Λpot values for all ions were less than 1. In the estimation of the drug Amitriptyline Hydrochloride in the pharmaceutical preparation (Amitriptyline tablets), the manufactured electrodes were used by following the direct process, the standard method of additions, the possible titration method and the homogeneity of the material sample, as well as the drug was estimated in urine and blood plasma with a recovery of not less than 100.57 for urine and 99.46 f for urine.

WEDM of complex profile of IN718: multi-objective GA-based optimization of surface roughness, dimensional deviation, and cutting speed

Over the past decade, components featuring complex curved geometries have become a prerequisite for the high performance of aeroengines, thus necessitating stringent limits for excellent surface quality and high dimensional precision. As such, the manufacturing of complex features presents machining challenges. Wire electric discharge machining is a non-conventional process that has the potential to effectively mitigate these challenges, but further research is needed. Specifically, the coated wire electrodes that are incorporated in machining have been examined in terms of their impact on cutting speed, but their influence on the surface roughness and the dimensional accuracies is somewhat unexplored. In this experimental study, the influence of zinc-coated copper wire (BroncoCut-X) and corresponding process parameters (wire tension, pulse-on-time, pulse-off-time, servo voltage, and wire feed) were scrutinized to machine a complex profile in IN718 superalloy. The response characteristics associated with the complex profile, namely, surface roughness, dimensional deviation, and cutting speed, were thoroughly investigated. The machining results were analysed through main effect plots, analysis of variance, and scanning electron microscopy. The results revealed that BroncoCut-X was effective in machining the complex curved geometry profiles (convex, concave, straight, and inclined) and produced the best results for the concave geometrical feature. Considering the conflicting nature of response attributes, multi-objective genetic algorithm was employed to obtain the best combination of control parameters for the each geometry of the complex profile. The best optimal solution set the values of control variables at 2.6405 g wire tension, 2.9931 μs pulse-on-time, 22.4108 μs pulse-off-time, 54.620 V servo voltage, and 4.1730 mm/s wire feed. The exactness of multi-objective genetic algorithm was verified through confirmatory tests wherein the average percentage error was found less than 2%.

Experimental Investigation of the AISI H-13 die steel by Wire-Cut EDM

The current study is done to provide a comprehensive report on the machining of AISI H-13 Die Steel with bare and coated wire electrodes. The study is carried out for the pulse duration-on time and pulse duration-off time process parameters effect on both electrodes and surface roughness is taken as response parameter of material along with the best viable combination of process parameter for machining.

Potentiometric determination of finsatride by novel ion selective electrodes

In this research, five ion selective electrodes for finsatride drug were successfully prepared including: coated wire electrode (CWE), coated graphite electrode (CGE), carbon paste electrode (CPE), carbon paste-carbon nanotube electrode (CPCNT) and carbon paste-nanosilica electrode (CPNS) depending on the formation of finsatride-TPB complex. Furthermore, the Nernastain response was studied by determination of slope and detection limit with the study pH effect on the response for finsatride electrodes and response time. However, the selectivity was calculated with applied the potentiometric method which including: direct, standard addition method and potentiometric titration for pure and pharmaceutical formulation of finsatride. The RSD was 2.82, 1.52, 2.04, 2.27, 1.84, respectively. And the 6.350 × 10-7, 7.449 × 10-8, 6.334 × 10-6, 5.316 × 10-6 and 5.433 × 10-6 M, respectively.

Sustainable production of high-uniformity workpiece surface quality in wire electrical discharge machining by fabricating surface microstructure on wire electrode

When the traditional wire electrode is used in wire electrical discharge machining (WEDM), the workpiece surface quality along thickness direction is always nonuniform which has a significant impact to the usability and reliability of workpiece. To address this issue, this paper aims to propose a new method of fabricating surface microstructure on wire electrode (SMWE) for sustainable production of high-uniformity workpiece surface quality. Firstly, an experimental research of workpiece surface quality uniformity is implemented when zinc coated wire electrode (ZCWE) is used. It can be found that the surface roughness (Ra) and surface quality on the middle area are the worst followed by the top area and bottom area. The uniformity of Ra can be up to 0.44. Additionally, the production process of SMWE is described which includes casting, coating, annealing and plastic processing. The forming mechanism of surface microstructure on wire electrode is based on the thermal expansion coefficient of coating layer is lower than that of wire core. And then, compared with ZCWE, the improvements of SMWE on the discharge characteristic and workpiece surface quality uniformity are analyzed. It can be obtained that SWEM can increase the probability of point discharge and the ratio of normal discharge status. Besides, SMWE can reduce the mean value of surface roughness by 17.3%–22.2% and increase the uniformity of surface roughness by 9.5%–52.1%. Namely, the proposed SMWE for sustainable production of high-uniformity workpiece surface quality is feasible. Eventually, the effects of process parameters on the uniformity of surface roughness are also analyzed. It can be found that small discharge peak current, short pulse on time, long pulse off time, high gap reference voltage and appropriate wire speed are recommended for high-uniformity surface quality.

Parametric analysis and GRA approach in WEDM of Al 7075 alloy

In the present research work, Taguchi grey relational analysis (GRA) technique have been employed to optimized the multi-performance characteristics in WEDM of Al 7075 alloy using brass coated wire electrode. The influence of input factors such as pulse duration (Ton), pulse interval (Toff), flushing pressure (Fp) and servo voltage (Sv) on output response machining speed (Vc) and corner inaccuracy (er) have been studied using deionized water as a dielectric fluid. Analysis of variance (ANOVA) and percentage of contribution have been performed on grey relational grade (GRG) to evaluate the influencing factors at 95% confidence level. Predicted results are validated by confirmatory experiments. From the analysis of confirmation experiments, it has been evident that an improvement of GR grade value is 0.0067 which is satisfactory.

A solid-contact Ca2+-selective electrode based on an inorganic redox buffer of Ag@AgCl/1-tetradecyl-3-methylimidazolium chloride as ion-to-electron transducer

For construction of solid-contact ion-selective electrodes (SC-ISEs), ion-to-electron transducers based on the redox capacitance transduction mechanism are currently restricted to organic materials. Exploring inorganic nanomaterials with high redox buffer capacities as intermediate layers for SC-ISEs would offer another alternative. Herein, a solid-contact calcium ion-selective electrode (SC–Ca2+-ISE) with a new inorganic redox buffer-Ag@AgCl/1-tetradecyl-3-methylimidazolium chloride (TMMCl) as the ion-to-electron transducer is presented. In this system, the predominant component core-shell Ag@AgCl nanoparticles with diameters ranging from 30 to 100 nm can be prepared through a two-step process. An ionic liquid TMMCl is used to offer a source of free Cl−. The developed SC-Ca2+-ISE exhibits a near Nernstian slope of 28.3 mV/decade for Ca2+ in the range of 10−6 - 10−2 M. By using of the inorganic redox buffer, the SC-Ca2+-ISE has a smaller impedance and higher capacitance than the coated-wire electrode, which guarantees a stable potential response. Additionally, the proposed SC-Ca2+-ISE shows excellent resistances to interferences of light, O2 and CO2, with a reduced water layer formed between the ion-selective membrane and the underlying solid contact. The developed inorganic redox buffer of Ag@AgCl/TMMCl can be effectively used as a new ion-to-electron transducer for construction of solid contact ISEs.

Single-Piece All-Solid-State Potential Ion-Selective Electrodes Integrated with Molecularly Imprinted Polymers (MIPs) for Neutral 2,4-Dichlorophenol Assessment.

A novel single-piece all-solid-state ion-selective electrode (SC/ISE) based on carbon-screen printed is introduced. Polyaniline (PANI) is dissolved in a membrane cocktail that contains the same components used for making a conventional ion-selective polyvinyl chloride (PVC) matrix membrane. The membrane, having the PANI, is directly drop-casted on a carbon substrate (screen-printed-carbon electrode). PANI was added to act as an intermediary between the substrate and the membrane for the charge transfer process. Under non-equilibrium sensing mechanism, the sensors revealed high sensitivity towards 2,4-dichlorophenol (DCP) over the linearity range 0.47 to 13 µM and a detection limit 0.13 µm. The selectivity was measured by the modified separate solution method (MSSM) and showed good selectivity towards 2,4-DCP over the most commonly studied ions. All measurements were done in 30 mm Tris buffer solution at a pH 5.0. Using constant-current chronopotentiometry, the potential drift for the proposed electrodes was checked. Improvement in the potential stability of the SPE was observed after the addition of PANI in the sensing membrane as compared to the corresponding coated-wire electrode (membrane without PANI). The applicability of the sensor has been checked by measuring 2,4-DCP in different water samples and the results were compared with the standard HPLC method.

A simple method to determine tramadol using a coated-wire electrode as a detector in the flow injection analysis

A new simple and fast electrochemical method has been developed, in the current paper, to quantify tramadol hydrochloride in pure solutions and pharmaceuticals, employing the flow injection analysis (FIA) technique. To achieve this, a coated-wire electrode detector has been manufactured using tramadol with phospho molibidic acid in the presence of chlorovinyl benzene. The characteristics of this electrode were studied by assessing the optimal conditions, concentration range, minimal limit of Nernst response, a minimal range of sensitivity, response time, flow rate, the degree of dispersion, accuracy, precision, and detection limits. The study also identified the selectivity of the electrode in the presence of other ions as interferences. The electrode gave the best Nernstian slope of the calibration curve at -58 mV per decade. The response time was 8 s; detection limit 1.2 × 10–6 M; concentration ranged between 100 and 0.01 mM, with a sampling rate of 90 samples per hour. Results of the statistical analysis confirmed that the developed method has high accuracy (the relative error was 0.8192%). The recovered percentage of tramadol from pharmaceutical dosage forms ranged 99.53 to 100.64%.

Analysis of surface performance measures on WEDM processed titanium alloy with coated electrodes

Owing to its distinct physical properties, titanium alloy is usually machined using unconventional machining process. In the present study, an effort has been performed to enhance the machinability of titanium alloy using wire electrical machining process with coated wire electrodes. An experimental investigation has been done to evaluate the significance of wire coating such as zinc and diffused coating on surface performance measures. The compositional analysis of the machined surface has been made to analyze the effects of coating on material deposition. From the experimental results, it has been inferred that diffused type of electrode has produced better surface morphology than conventional wire electrodes.

Electric Discharge Machining of Tungsten Carbide using Uncoated and Coated Wire Electrodes: Analysis of Cutting Speed and Workpiece Geometrical Accuracy

Tungsten carbide is an important tool and die material due to its excellent mechanical properties such as high hardness, good toughness, and wear resistance. Wire electric discharge machining (WEDM) is regarded as a process capable of machining complex geometries and curved features in difficult-to-cut tungsten carbide. The present research work is carried out to study the influence of wire electrode, workpiece taper angle, and WEDM parameters on cutting speed and geometrical error of curved profile machined in tungsten carbide. Experiments are performed based on Taguchi’s L18 orthogonal array using two types of wires; uncoated brass wire and zinc-coated brass wire. Experimental results indicate that zinc-coated brass wire offers higher cutting speed as compared to uncoated brass wire. Main effects plots show that pulse-on time and pulse-off time are the most significant factors affecting cutting speed while taper angle is the most significant factor for geometrical error.