Solvent Mediator Research Articles

Energetic aqueous zinc-sulfur battery achieved via co-solvent and redox mediator synergistic regulation

Aqueous Zn–S batteries (AZSBs) have received significant attention due to the outstanding energy density, low cost, and high safety. However, the slow kinetics and poor reversibility of the sulfur conversion reaction, coupled with the formation of dendrites in zinc anode and hydrogen evolution reaction (HER), hinder the practical applications of AZSBs. In this paper, we developed a novel co-solvent electrolyte that utilizes N-methylpyridine (NMP) and KI as additives to regulate the cathode reversibility and anode stability synergistically. Firstly, the electrophilic group of NMP (–CO–NR2-) effectively activates the oxidation of I− to form I3−. The resulting I3−/I− redox mediator participates in the sulfur conversion reaction and lowers its energy barrier, thus enhancing the reaction kinetics of ZnS ↔ S and inhibiting the formation of irreversible by-products. Secondly, NMP alters the solvation structure of Zn(H2O)62+, achieving uniform deposition of Zn2+ and inhibiting the growth of zinc dendrites. Thirdly, NMP forms a dense solid-electrolyte-interphase layer between the zinc metal and H2O during cycling, inhibiting HER. Under the synergistic effect from solvent and redox mediator, AZSBs exhibit an impressive capacity of 775 mAh g−1 at 5 A g−1 (10 C) with 77.5 % capacity retention after 300 cycles.

Enhancing the Sustainability of Eco-Friendly Potentiometric Ion-Selective Electrodes for Stability-Indicating Measurement of Ethamsylate: Application in Bulk and Pharmaceutical Formulations.

Through the use of sustainable and green chemistry concepts, scientists need to decrease waste, conserve energy, and develop safe substitutes for hazardous compounds, all for protecting and benefiting society and the environment. Four novel eco-friendly ion selective electrodes (ISE) were generated to determine Ethamsylate (ETM) in bulk powder and different pharmaceutical formulations. The present electrodes were fabricated to clearly distinguish ETM from a variety of inorganic, organic ions, sugars, some common drug excipients and the degradation product, hydroquinone (HQ) of ETM, and thus used for stability-indicating methods. The electrodes fabrication was based on 2-nitrophenyl octyl ether (NPOE) that was employed as a plasticizer in electrodes 1, 2, and 3 within a polymeric matrix of polyvinyl chloride (PVC) except for electrode 4, in which dibutyl sebacate was used as a plasticizer. Electrodes 1 and 2 were fabricated usingtetradodecylammonium bromide as an anionic exchanger, adding 4-sulfocalix-8-arene as an ionophore only to electrode 2 and preparing electrode 1 without incorporation of an ionophore. The fabrication of electrodes 3 and 4 was based on ethamsylate-tetraphenylborate (ETM-TPB) as an ion-association complex in a PVC matrix. The environmental sustainability was assessed using the green analytical procedure index (GAPI), and analytical greenness metric for sample preparation (AGREEprep). Electrodes 1 and 2 had linear dynamic ranges of 10-1-10-5 mol/L and 10-1-10-4 mol/L, respectively, with a Nernstian slope of 49.6 and 53.2 mV/decade, respectively. Electrodes 3 and 4 had linear dynamic ranges of 10-1-10-4 mol/L, with a Nernstian slope of 43.9 and 40.2 mV/decade, respectively. The electrodes' selectivity coefficients showed good selectivity for ETM. The utility of 4-sulfocalix-8-arene as an ionophore had a significant influence on increasing the membrane sensitivity and selectivity of electrode 2 compared to other electrodes. Four novel eco-friendly ISEs were used for determination of ETM in bulk powder and different pharmaceutical formulations. Different experimental parameters were performed to optimize the determination conditions such as solvent mediators, dynamic response time, effect of pH, and temperature. Stability-indicating measurement of ETM in the presence of its degradate HQ and co-formulated drug tranexamic acid. Using new ecological assessment tools to determine whiteness and greenness profiles.

Development of a Highly Selective Chloride Ion Potentiometric Sensor Utilizing a Novel N, N-Ethylene-bis-(Salicylideneaminato) Zinc (II) Molecule for Clean Environment

The present study focuses on the advancement of a chloride ion potentiometric sensor that exhibits high selectivity. This sensor employs a novel molecule, namely N, N-Ethylene-bis-(Salicylideneaminato) zinc (II), in order to achieve accurate measurements in the pursuit of maintaining a clean environment. N, N′-Ethylenebis( salicylideneaminato) nickel (II) ionophore has been generated as well as evaluated using analysis of NMR, IR and C, H, N. Subsequently, membranes incorporating the ionophore (I) were developed utilizing poly(vinyl chloride) (PVC) as a matrix, with plasticizing solvent mediators including Dioctyl phthalate (DOP), chloronapthalene (CN), Dibutyl phthalate (DBP), and tri-n-butylphosphate (TBP). Additionally, catalyzed cation discriminator, hexadecyltrimethylammonium bromide (HDTMA) was employed to enhance membrane formation. This sensor performed better than all other variants. Its membrane composition was 5 mg ionophore, 32 mg PVC, 60 mg DBP, and 3 mg HDTMA. Notably, the sensor exhibited an extended operational range of 2.0×10−6 to 1.0×10−1 M, in addition to Nernstian compliance (58.8 mV/Decade) within pH span of 2.3–9.3, and an impressive response time of 19 s. A detection range as low as 1.64×10−6 was attained, indicative of its high sensitivity. Furthermore, the sensor exhibited remarkable selectivity for chloride ions, as confirmed by selectivity coefficient measurements obtained through fixed interference technique (FIM). The sensor demonstrated a satisfactory three-month shelf life and acceptable repeatability. In practical application, the sensor demonstrated effectiveness in quantifying chloride ions in wastewater samples. This work addresses important sustainability issues while contributing to an improved comprehension of the underlying concepts of self-assembled behavior and setting up an option for the generation of efficient sensors with potential uses in photonics and microelectronics.

Electrochemically-selective electrode for quantification of dorzolamide in bulk drug substance and dosage form

Three smart carbon paste electrodes were fabricated to quantify dorzolamide hydrochloride DRZ, including conventional carbon paste I, modified carbon paste embedding Silica II, and modified carbon paste embedding β-cyclodextrin III. This study is based on the insertion of DRZ with phosphomolybdic acid to create an electroactive moiety dorzolamide-phosphomolybdate ion exchanger using a solvent mediator dibutyl phthalate. The three constructed carbon paste electrodes displayed Nernstian responses and linear concentration ranges with lower detection limits. The vital performance of the created electrodes was verified in relation to various parameters. The electrodes enhance the selective determination of DRZ in the presence of inorganic ions, a co-formulated drug in the dosage form timolol maleate, and the excipient benzalkonium chloride. The modified carbon paste electrode including Silica was utilized to detect DRZ in ophthalmic eye drop form utilizing the direct calibration curve and potentiometric titration methods. Satisfactory findings were achieved by comparing them to other reported methods.

Electroanalytical sensors-based biogenic synthesized metal oxide nanoparticles for potentiometric assay of pantoprazole sodium

ABSTRACT Two modified coated membrane sensors were designed and tested. Pantoprazole-phosphotungstate was prepared by a reaction of pantoprazole with phosphotungstic acid in the solvent mediator o-nitrophenyloctyl ether. Two metal oxide nanoparticles nickel oxide and iron oxide nanoparticles, were synthesized from green sources Matricaria recutita flowers and Salvia officinalis leaves extracts, respectively. These nanoparticles were used for the potentiometric assay of pantoprazole sodium in the authentic sample and commercial products. The results showed that the improved nickel oxide and iron oxide nanosensors exhibited linearity using the concentration range of 1.0 × 10−9–1.0 × 10−2 and 1.0 × 10−10–1.0 × 10−2 mol L−1, respectively compared with 1.0 × 10−6–1.0 × 10−2 mol L−1 for the normally coated sensor. The lower limits of detection (7.6 × 10−6, 2.3 × 10−10, 2.8 × 10−11 mol L−1) and quantification (1.0 × 10−6, 1.0 × 10−9, 1.0 × 10−10 mol L−1) were determined for each of the three proposed sensors. Least squares calculations gave EmV = (27.266 ± 0.5) log (pantoprazole) + 433.37, EmV = (30.967 ± 0.3) log (pantoprazole) + 432.24 for the enriched nano-metal oxides, and EmV = (26.642 ± 0.6) log (pantoprazole) + 443.69 for the conventional type, respectively with correlation coefficients around 0.999 for the proposed sensors. The accuracy and precision of the modified potentiometric systems were estimated and the results showed excellent validity and suitability for the determination of pantoprazole in an authentic sample.

Modified Screen-Printed Microchip for Potentiometric Detection of Terbinafine Drugs

The development of miniaturized microchips has widespread and growing interest in manufacturing potentiometric sensors with extremely valuable modifying response characteristics. In this context, here, we demonstrate microfabrication, electrochemical evaluation, and analytical applications of disposable thin-film potentiometric microsensors responsive to terbinafine antifungal medication. Miniaturized microchips have been realized by integration of the sensitive layer membrane modified by carbon nanotubes onto the surface of the plastic screen-printed microchip support using a new approach, which has been recently developed. The sensitive membrane comprises terbinafine HCl: ammonium heptamolybdate complex ion pair as ionophore, o-nitrophenyl octyl ether as a solvent mediator, potassium tetrakis (4-chlorophenyl) borate as an anion excluder, and polyvinyl chloride as support. The microsensor based on this plasticised sensitive membrane provides the Nernstian response and covers a wide concentration range of terbinafine of 10−8–10−2 mole·L−1. The merits offered by the elaborated terbinafine microchip over the bulk-based electrode include reasonable sensitivity (58.5 mV/concentration decade), fast response time (∼30 s.), long-term stability (4 months), integration, and automation feasibility. Furthermore, microfabricated terbinafine chips were successfully applied to the measurements of the investigated medication in some real samples with high accuracy (96.9%) and precision (<3%).

Potential Application of Carbon‐based Electrical Sensor for the Highly Sensitive Diltiazem HCl Quantification in its Pharmaceutical Products and Biological Samples

AbstractDiltiazem (DTZ) hydrochloride, a calcium channel blocker compound, is a very well‐known drug used by many clinicians to treat important diseases playing a role in increased morbidity and mortality among adults worldwide, namely hypertension, cardiac arrhythmia, and ischemic heart disease (angina pectoris). These diseases are a common public health concern, implying that the construction of a specific, accurate, and simple sensor for DTZ determination is needed. Herein, an innovative, portable, and sensitive modified carbon paste electrode (MCPE) was seamlessly developed based on the affordable green compound N‐bromosuccinimide (NBS) as a sensing material and tricresyl phosphate as a solvent mediator for the voltammetric determination of DTZ. The proposed NBS‐MCPE exhibited an excellent electrocatalytic activity towards the oxidation of DTZ molecules in a phosphate buffer solution of pH 5.0 in presence of 20 μM sodium dodecyl sulfate to improve the developed sensor performance. The sensor was found to respond linearly to the DTZ drug over a wide concentration ranging from 1 μM to 300 μM with a low limit of detection. LSV and EIS measurements were also used to scrutinize our sensor, in addition to using scanning electron microscopy and energy dispersive X‐ray analysis techniques for its surface morphology inspection before and after soaking in the drug‐containing solution. The applicability of the proposed sensor for the rapid, sensitive, and selective determination of DTZ in pharmaceutical preparation and human urine samples was assessed and the obtained results were compared with that of the reported HPLC analytical method.

On the analytical response of lead(II) selective electrodes using 1-aroyl-3,3-dimethylthioureas as ionophores: membrane analysis and quantum chemical calculations

Solid-state Pb2+-ion selective electrodes (Pb2+-ISEs) based on liquid membranes using three 1-aroyl-3,3-dimethylthioureas as ionophores were developed. The receptors differ structurally in the aromatic ring of the 1-aroyl group and have been labeled as FDM, BDM, and TDM. The analytical performance of the constructed electrodes was studied by determining the calibration parameters. The electrodes showed Nernstian behavior with average sensitivities of 30.1, 31.5 and 26.6 mV/dec, as well as average lifetimes of 100, 60 and 7 days, respectively. Cd2+ and Cu2+ cations were interfering toward Pb2+ ions detection. The sensing membranes were studied by SEM-EDS and the results have suggested the formation of aggregates through time related to complex species Pb2+-aroylthioureas. Additionally, quantum chemical calculations were carried out at the B3LYP/6-311G(d,p) level of theory to compute the geometry, frontier molecular orbital energies and global reactivity parameters of the aroylthioureas in tributyl phosphate (TBP) as solvent mediator. Correlation studies between the receptor’s quantum chemical parameters and the experimental analytical response of the Pb2+-ISEs were addressed in order to clarify the differences observed in the analytical response of the constructed electrodes. The results support the chemical model of interaction between thioureas and Pb2+ ions through orbital control involving vacant d-orbitals of the metal ion and electrons from the HOMO of the organic molecule.

Advanced Functionalized CeO2/Al2O3 Nanocomposite Sensor for Determination of Opioid Medication Tramadol Hydrochloride in Pharmaceutical Formulations.

Background: The exceptional characteristics of cerium oxide (CeO2) and aluminum oxide (Al2O3) nanoscales have inspired significant attention to those nanocomposites as possible electroactive resources for applications of sensing and biosensing. Methods: In this research, an innovative new factionalized CeO2/Al2O3 nanocomposite membrane sensor was presented to assess tramadol hydrochloride (TRD) in marketable products. Results: Tramadol-phosphomolybdate (TRD-PM) was formed by mixing tramadol hydrochloride and phosphomolybdic acid (PMA) in the attendance of polymeric matrix and o-nitrophenyloctyl ether solvent mediator. With 1.0 × 10−10–1.0 × 10−2 mol L−1 as a range of linearity and EmV = (57.567 ± 0.2) log [TRD] + 676.29 as a regression equation, the functionalized sensor using TRD-PM-CeO2/Al2O3 nanocomposite showed great selectivity and sensitivity for the discriminating and measurement of TRD. Using the regression equation EmV = (52.143 ± 0.4) log [TRD] + 431.45, the unmodified coated wire sensor of TRD-PM, on the other hand, showed a Nernstian response between 1.0 × 10−6 and 1.0 × 10−2 mol L−1, Using the methodology’s specified guidelines, the proposed improved potentiometric system was validated against several criteria. Conclusion: The suggested method is suitable for the determination of TRD in its products.

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.

New Construction of Functionalized CuO/Al2O3 Nanocomposite-Based Polymeric Sensor for Potentiometric Estimation of Naltrexone Hydrochloride in Commercial Formulations.

Electrically conductive polymeric nanocomposites with nanoparticles are adaptable types of nanomaterials that are prospective for various applications. The extraordinary features of copper oxide (CuO) and aluminium oxide (Al2O3) nanostructures, encourages extensive studies to prospect these metal oxide nanocomposites as potential electroactive materials in sensing and biosensing applications. This study suggested a new CuO/Al2O3 nanocomposite-based polymeric coated wire membrane sensor for estimating naltrexone hydrochloride (NTX) in commercial formulations. Naltrexone hydrochloride and sodium tetraphenylborate (Na-TPB) were incorporated in the presence of polymeric polyvinyl chloride (PVC) and solvent mediator o-nitrophenyloctyl ether (o-NPOE) to form naltrexone tetraphenylborate (NTX-TPB) as an electroactive material. The modified sensor using NTX-TPB-CuO/Al2O3 nanocomposite displayed high selectivity and sensitivity for the discrimination and quantification of NTX with a linearity range 1.0 × 10−9–1.0 × 10−2 mol L−1 and a regression equation EmV = (58.25 ± 0.3) log [NTX] + 754.25. Contrarily, the unmodified coated wire sensor of NTX-TPB exhibited a Nernstian response at 1.0 × 10−5–1.0 × 10−2 mol L−1 and a regression equation EmV = (52.1 ± 0.2) log [NTX] + 406.6. The suggested modified potentiometric system was validated with respect to various criteria using the methodology recommended guidelines.

Solvent Mediating the in Situ Self-Assembly of Polysaccharides for 3D Printing Biomimetic Tissue Scaffolds.

Intensively studied 3D printing technology is frequently hindered by the effective printable ink preparation method. Herein, we propose an elegant and gentle solvent consumption strategy to slowly disrupt the thermodynamic stability of the biopolymer (polysaccharide: cellulose, chitin, and chitosan) solution to slightly induce the molecule chains to in situ self-assemble into nanostructures for regulating the rheological properties, eventually achieving the acceptable printability. The polysaccharides are dissolved in the alkali/urea solvent. The weak Lewis acid fumed silica (as solvent mediator) is used to (i) slowly and partially consume the alkali/urea solvent to induce the polysaccharide chains to self-assemble into nanofibers to form a percolating network in a limited scale without leading to gelation and (ii) act as the support to increase the solution modulus, for achieving superior printability and scaffold design flexibility. As a demonstration, the resulting polysaccharide scaffolds with biomimetic nanofibrous structures exhibit superior performances in both the cell-free and cell-loaded bone tissue engineering strategies, showing the potential in tissue engineering. Moreover, the fumed silica could be completely removed by alkali treatment without defecting the nanofibrous structure, showing the potential in various applications. We anticipate our solvent-mediated 3D printing ink preparation concept could be used to fabricate other polymeric facile inks and for widespread applications in diverse fields.

Supramolecular Atropine Potentiometric Sensor

A supramolecular atropine sensor was developed, using cucurbit[6]uril as the recognition element. The solid-contact electrode is based on a polymeric membrane incorporating cucurbit[6]uril (CB[6]) as an ionophore, 2-nitrophenyl octyl ether as a solvent mediator, and potassium tetrakis (4-chlorophenyl) borate as an additive. In a MES-NaOH buffer at pH 6, the performance of the atropine sensor is characterized by a slope of (58.7 ± 0.6) mV/dec with a practical detection limit of (6.30 ± 1.62) × 10−7 mol/L and a lower limit of the linear range of (1.52 ± 0.64) × 10−6 mol/L. Selectivity coefficients were determined for different ions and excipients. The obtained results were bolstered by the docking and spectroscopic studies which demonstrated the interaction between atropine and CB[6]. The accuracy of the potentiometric analysis of atropine content in certified reference material was evaluated by the t-Student test. The herein proposed sensor answers the need for reliable methods providing better management of this hospital drug shelf-life while reducing its flush and remediation costs.

Hybrid Nanocomposite Based Graphene Sensor for Ultrasensitive Clomipramine HCl Detection

AbstractA potentiometric sensor modified with a nanocomposite of montmorillonite sheets decorated with polyaniline nanofibers (MT‐PANI‐NFs) as an efficient electroactive material and tricresyl phosphate (TCP) as a solvent mediator has been developed for the estimation of clomipramine HCl (CLP.HCl). The optimum potentiometric performance of the sensor was achieved by mixing of MT‐PANI‐NFs : TCP : graphene with a ratio of 2.69 : 30.11 : 67.20 (% wt/wt). The sensor exhibited a Nernstian slope of 59.0±0.1 mV decade−1 over the concentration range of 1.0×10−5−1.0×10−2 mol L−1 with a theoretically calculated detection limit of 5.0×10−6 mol L−1. The sensor performance was scrutinized in terms of several factors including thermal stability, pH effect, response time and selectivity. As, it displayed a high thermal stability at various temperature degrees (10–60 °C) with pH independency in the range of 3.5–8.5. Additionally, the developed sensor exhibited a very rapid performance for CLP.HCl detection with a fast response time of 4 s and reflecting a superior selectivity towards CLP.HCl over the other interfering species. SEM (scanning electron microscope) was used as a characteristic tool for the investigation of the proposed graphene sensor surface. Furthermore, the graphene sensor has been efficiently used for CLP.HCl estimation in its pharmaceutical formulations.

Ni(II)-selective PVC membrane sensor based on 1,2,4-triazole bis Schiff base ionophore: Synthesis, characterization and application for potentiometric titration of Ni2+ ions against EDTA

This study involves the preparation and investigation of a novel and highly selective poly(vinyl chloride)-based membrane of 2-((5-(2-hydroxy-3-methoxybenzylideneamino)-2H-1,2,4-triazol-3-ylimino)methyl)-6-methoxyphenol Schiff base ligand (HMBT), which is a neutral ionophore with sodium tetraphenyl borate (STB) in the form of an excluder and o -nitrophenyloctyl ether ( o -NPOE) in the form of solvent mediators (plasticizing) as a Ni(II)-selective electrode. The observation of optimal performance was done wherein the membrane was shown to have the HMBT–PVC–NPOE-STB composition of 4:32:63:1.It worked effectively across a broad range of concentration (1.0 × 10 −8 to 1.0 × 10 −2 mol L −1 ). Meanwhile, the Nernstian slope was recorded as 29.3 mV per decade of activity between pH 3.0 and 8.0. The response time of this electrode was fast at 11 s which was used for a span of 100 days with sound reproducibility. According to the selectivity coefficients for trivalent, divalent, and monovalent cations, excellent selectivity was indicated for Ni(II) ions across a large number of citations, whereas no interference was caused by anions like PO 4 3− , SO 4 2− and Cl − . The proposed method in this study was applied successfully to determine Ni(II) content in different samples of water, obtaining suitable recoveries. Additionally, the probed sensor is utilized as indicator electrode when considering Ni 2+ ion potentiometric titration against EDTA. In addition, the chelate’s geometry and structure of the complex formed between Ni 2+ ions and HMBT, abbreviated as HMBT-Ni 2 , was evaluated by separating the solid product. Complex structure was confirmed based on alternative analytical and spectral methods to be structured in the bimetallic form with the formula [Ni 2 (HMBT)(H 2 O) 2 Cl 2 ]. The diamagnetic nature of the complex, which was concluded from the room temperature magnetic moment measurement combined with the UV–Vis measurement, suggested the square planar geometry around the Ni centers.

A Novel Reduced Graphene Oxide Modified Carbon Paste Electrode for Potentiometric Determination of Trihexyphenidyl Hydrochloride in Pharmaceutical and Biological Matrices.

A novel promising carbon paste electrode with excellent potentiometric properties was prepared for the analysis of trihexyphenidyl hydrochloride (THP), the acetylcholine receptor and an anticholinergic drug in real samples. It contains 10.2% trihexyphenidy-tetraphenylborate ionic pair as the electroactive material, with the addition of 3.9% reduced graphene oxide and 0.3% of anionic additive into the paste, which consists of 45.0% dibutylphthalate as the solvent mediator and 40.6% graphite. Under the optimized experimental conditions, the electrode showed a Nernstian slope of 58.9 ± 0.2 mV/decade with a regression coefficient of 0.9992. It exhibited high selectivity and reproducibility as well as a fast and linear dynamic response range from 4.0 × 10−7 to 1.0 × 10−2 M. The electrode remained usable for up to 19 days. Analytical applications showed excellent recoveries ranging from 96.8 to 101.7%, LOD was 2.5 × 10−7 M. The electrode was successfully used for THP analysis of pharmaceutical and biological samples.

Highly Functionalized Modified Metal Oxides Polymeric Sensors for Potentiometric Determination of Letrozole in Commercial Oral Tablets and Biosamples.

The advanced and high-functional activities of magnesium oxide and copper oxide nanoparticles encourage the extensive use of these metal oxides as remarkable electroactive materials in electrochemical and sensing detections. The current study described a comparative sensing activity and selectivity of modified coated wire membrane sensors enriched with magnesium oxide and copper oxide nanoparticles for quantifying the breast cancer medication letrozole (LTZ) in its pharmaceutical form and human plasma. The fabricated sensors were based on the incorporation of LTZ with phosphomolybdic acid (PMA) to form the electroactive complex letrozole-phosphomolybate (LTZ-PM) in the presence of o-nitrophenyloctyl ether (o-NPOE) as a solvent mediator. Under optimum conditions, the modified sensors LTZ-PM-MgONPs and LTZ-PM-CuONPs demonstrated linear relationships of 1.0 × 10−8–1.0 × 10−2 and 1.0 × 10−10–1.0 × 10−2 mol L−1, respectively. Least square equations were calculated as EmV = (56.4 ± 0.7) log [LTZ] + 569.6 and EmV = (58.7 ± 0.3) log [LTZ] + 692.6 for LTZ-PM-MgONPs and LTZ-PM-CuONPs, respectively. The conventional type LTZ-PM showed a potential response EmV = (53.3 ± 0.5) log [LTZ] + 451.4 over concentration range of 1.0 × 10−6–1.0 × 10−2 mol L−1. The suggested sensors were successfully used to determine LTZ in pharmaceutical formulations and biosamples. Method validation ensured the suitability of the suggested potentiometric sensors.

Exploitation of o-benzoyl benzoic acid as an efficient electroactive material for selective determination of Cr (III) ions in pharmaceutical samples and industrial waste water using carbon sensor

Herein, for the first time, o-benzoyl benzoic acid has been explored as a promising electroactive material for the fabrication of sensitive, precise and accurate carbon paste electrode (CPE) for selective detection of Cr (III) ion. o-benzoyl benzoic acid (o-BBA) as a sensing material and tricresylphosphate (TCP) as a solvent mediator improved the developed sensor performance to get the Nernstian cationic slope of 20.03 ± 0.11 mV decade−1 within the concentration range of 5.0 × 10−7-1.0 × 10−1 mol L−1. The sensor displayed a fast response time of 12 s reflecting a pH independency over the pH range of 3.1–4.7. Moreover, the reaction between the sensing material and Cr (III) ion on the developed sensor surface was elucidated using the microscopic technique such as scanning electron microscope (SEM) in addition to the energy dispersive X-ray analyzer (EDX). The proposed sensor showed an adequate shelf lifetime (∼33 days). The values of potentiometric selectivity coefficient were obtained by fixed interference and separate solution methods affirming a high distinguishing power of the fabricated sensor toward Cr (III) ions over the other interfering ions. The established sensor could be utilized with a promising success for the Cr (III) ion estimation in the industrial waste water and in the pharmaceutical forms. Additionally, it has been employed as a promising indicator sensor with a superior performance for potentiometric titration of Cr (III) ion against EDTA.

Effective screen-printed potentiometric devices modified with carbon nanotubes for the detection of chlorogenic acid: application to food quality monitoring.

All-solid state screen-printed electrodes were fabricated for chlorogenic acid (CGA) detection. The screen-printed platforms were modified with multi-walled carbon nanotubes (MWCNTs) to work as a lipophilic solid-contact transducer. The sensing-membrane was plasticized with a suitable solvent mediator and incorporating [NiII(bathophenanthroline)3][CGA]2 complex as a sensory material. In a 30 mM phosphate solution (buffer, pH 6), the sensor revealed a Nernstian-response towards CGA ions with a slope of −55.1 ± 1.1 (r2 = 0.9997) over the linear range 1.0 × 10−7 to 1.0 × 10−3 (0.035–354.31 μg mL−1) with a detection limit 7.0 × 10−8 M (24.8 ng mL−1). It revealed a stable potentiometric response with excellent reproducibility and enhanced selectivity over several common ions. Short-term potential stability and the interfacial sensor capacitance was estimated using both electrochemical-impedance spectroscopy (EIS) and chronopotentiometry techniques. The presented electrochemical platform revealed the merits of design simplicity, ease of miniaturization, good potential-stability, and cost-effectiveness. It is successfully applied to CGA determination in different coffee beans extracts and juice samples. The data obtained were compared with those obtained by liquid chromatography reference method (HPLC).

New Functionalized Polymeric Sensor Based NiO/MgO Nanocomposite for Potentiometric Determination of Doxorubicin Hydrochloride in Commercial Injections and Human Plasma.

The ultra-functional potential of nickel oxide (NiO) and magnesium oxide (MgO) nanoparticles (NPs), provides for extensive attention in the use of these metal oxides as a remarkable and electroactive nanocomposite in potentiometric and sensing investigations. This work proposed a new strategy for quantifying doxorubicin hydrochloride (DOX) in pharmaceuticals and human plasma by preparing a NiO/MgO core-shell nanocomposite modified coated wire membrane sensor. Doxorubicin hydrochloride was incorporated with phosphomolybdic acid (PMA) to produce doxorubicin hydrochloride phosphomolybdate (DOX-PM) as an electroactive material in the presence of polymeric high molecular weight poly vinyl chloride (PVC) and solvent mediator o-nitrophenyloctyl ether (o-NPOE). The modified sensor exhibited ultra sensitivity and high selectivity for the detection and quantification of doxorubicin hydrochloride with a linear relationship in the range of 1.0 × 10−11–1.0 × 10−2 mol L−1. The equation of regression was estimated to be EmV = (57.86 ± 0.8) log [DOX] + 723.19. However, the conventional type DOX-PM showed a potential response over a concentration range of 1.0 × 10−6–1.0 × 10−2 mol L−1 and a regression equation of EmV = (52.92 ± 0.5) log [DOX] + 453.42. The suggested sensors were successfully used in the determination of doxorubicin hydrochloride in commercial injections and human plasma.