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The different structural‐type zeolites (FER, MFI, FAU, BEA) are investigated as catalysts in (bio)isobutanol conversion into linear butenes. The zeolites' structure and morphology are confirmed by XRD, N2 (77 K) ad(de)sorption, SEM, EDX, XPS, and 27Al, 29Si, 1H MAS NMR, 1H‐29Si CP MAS NMR. The nature and strength of acid‐base sites are determined by FTIR spectroscopy of adsorbed pyridine, potentiometric titration, and TPD of NH3/CO2/H2O with MS control. The acid‐base properties of the zeolites′ surfaces influence their catalytic properties in the target process. The higher selectivity towards linear butene isomers achieved over FER and MFI can be explained by the high strength and density of Brønsted acid sites (over 90 % of the total surface acidity). MFI might be regarded as a potential material for the creation of novel catalysts for isobutanol conversion into linear butenes at moderate temperatures (448–473 K) since it offers greater operating stability throughout the process. [ABSTRACT FROM AUTHOR]

A newly prepared solid contact ion selective electrode based on polyvinyl chloride membrane has been optimized and developed for determining nitrazepam in its pure form and synthetically prepared tablet dosage form. The proposed electrode was fabricated based on zeolite modified carbon paste electrode as a solid contact acting as a support for the membrane of PVC containing the ion complex of nitrazepam‐tetraphenyl borate as an electroactive material, and the plasticizer dibutyl phthalate. By improving the composition, the potentiometric properties were further enhanced, and the sensor achieved a Nernstian slope of 60.89 mV dec−1. The sensor was effective for detecting nitrazepam in the concentration range of 1.0×10−7 to 1.0×10−2 M, with a detection limit of 4.7×10−8 M. The sensor demonstrated excellent reversibility and reproducibility with a fast response time and application over a wide pH range. The developed electrode showed no significant effect when tested with various interfering species. It is successfully applied for accurate determination of nitrazepam in pure form, synthetically prepared tablet and spiked human plasma. The developed technique was validated and demonstrated high accuracy and precision. When compared statistically with the official method, there were no significant differences observed. [ABSTRACT FROM AUTHOR]

Self‐powered pressure detection using smart wearable devices is the subject of intense research attention, which is intended to address the critical need for prolonged and uninterrupted operations. Current piezoelectric and triboelectric sensors well respond to dynamic stimuli while overlooking static stimuli. This study proposes a dual‐response potentiometric pressure sensor that responds to both dynamic and static stimuli. The proposed sensor utilizes interdigital electrodes with MnO2/carbon/polyvinyl alcohol (PVA) as the cathode and conductive silver paste as the anode. The electrolyte layer incorporates a mixed hydrogel of PVA and phosphoric acid. The optimized interdigital electrodes and sandpaper‐like microstructured surface of the hydrogel electrolyte contribute to enhanced performance by facilitating an increased contact area between the electrolyte and electrodes. The sensor features an open‐circuit voltage of 0.927 V, a short‐circuit current of 6 µA, a higher sensitivity of 14 mV/kPa, and outstanding cycling performance (>5000 cycles). It can accurately recognize letter writing and enable capacitor charging and LED lighting. Additionally, a data acquisition and display system employing the proposed sensor, which facilitates the monitoring of athletes' rehabilitation training, and machine learning algorithms that effectively guide rehabilitation actions are presented. This study offers novel solutions for the future development of smart wearable devices. [ABSTRACT FROM AUTHOR]

Neuropeptide Y (NPY) plays a central role in a variety of emotional and physiological functions in humans, such as forming a part of the body′s response to stress and anxiety. This work compares the impact of MCH and PEG spacer molecules on the performance of a potentiometric NPY sensor. An NPY‐specific DNA aptamer with thiol termination was immobilized onto a gold electrode surface. The performance of the sensor is compared when either an MCH‐ or PEG‐based self‐assembled monolayer is formed following aptamer immobilization. Backfilling the surface with alkanethiol spacer molecules like these is key for proper conformational folding of aptamer‐target binding. Non‐specific adhesion of NPY to the MCH‐based sensor surface was observed via surface plasmon resonance (SPR), and then confirmed via potentiometry. It is then shown that PEG improves the sensor′s sensitivity to NPY compared to the surfaces with an MCH‐based SAM. We achieve the detection of picomolar range NPY levels in buffer with a sensitivity of 36.1 mV/decade for the aptamer and PEG‐based sensor surface, thus demonstrating the promise of potentiometric sensing of NPY for future wearable deployment. The sensor′s selectivity was also studied via exposure to cortisol, a different stress marker, resulting in a 13x smaller differential voltage (aptamer‐specific) response compared to that of NPY. [ABSTRACT FROM AUTHOR]

Phosphate is an important fertilizer in agriculture and electrochemical sensors based on cobalt (Co) are promising for measurement of phosphate. The deposition of Co onto conductive substrates to form a nano/microstructured Co layer with rich active sites is a typical strategy to improve detection performances. However, the widely used substrates show smooth surfaces, which cannot provide extra active sites. Herein, a high‐performance phosphate sensor is fabricated by generating Co nanoparticles (NPs) on a hierarchically porous laser‐induced graphene (LIG) matrix with a large surface area. Specifically, a Co layer is first electroplated on the LIG matrix. Nevertheless, the pores of LIG will be blocked by the dense Co layer so the performances of the fabricated LIG‐Co sensor exhibit limited enhancements. Therefore, a "nearly all etching (NAE)" technique is developed to transform the dense Co layer to dispersive Co NPs and re‐expose the pores of LIG, both increasing the active sites. Compared to the LIG‐Co sensor, the LIG‐Co NP sensor displays overall superiority. The response time, sensitivity, and linearity are enhanced from ≈60 to ≈10 s, from 0.012 to 0.069 V dec−1, and from 0.973 to 0.998, respectively. The LIG‐Co NP sensor also shows a decent anti‐interference capability. [ABSTRACT FROM AUTHOR]

Intense pulsed light was investigated for partial photoreduction of AgCl in a poly(vinyl butyral) matrix to obtain a Ag/AgCl reference membrane. The membrane was deposited on both glassy carbon and inkjet‐printed silver electrodes giving all‐solid‐state reference electrodes. Regardless of the electrode material, a sufficient potential stability was obtained in a broad concentration range of various salt solutions. Long‐term potential stability was significantly improved with inkjet‐printed silver electrical contacts. The electroanalytical performance of inkjet‐printed electrodes was successfully demonstrated in potentiometric and amperometric systems. [ABSTRACT FROM AUTHOR]

This work demonstrates the use of jute stick extract as a reducing and stabilizing agent for the synthesis of spherical gold nanoparticles (AuNPs). In UV‐Vis spectroscopy, peak at 550 nm was used to confirm the formation of AuNPs. The spherical surface morphology of AuNPs was determined through SEM and TEM analysis. While XRD investigation revealed the crystallinity of the prepared AuNPs. To ensure the biocompatibility of synthesized AuNPs, a bacterial investigation was conducted with negative results towards bacterial strain. The, modified FTO with AuNPs were able to detect glucose in CV analysis and the constructed sensor displayed a wide linear range of 50 μM to 40 mM with a detection limit of 20 μM. Scan rate analysis was performed to determine the charge transfer coefficient (0.42) and Tafel slope (102 mV/decade). Furthermore, the interfacial surface mechanism is illustrated to understand the interaction of glucose with the electrode surface in an alkaline medium and the product formation through the dehydrogenation and hydrolysis process. The prepared sensor also showed good stability, reproducibility, and anti‐interference capabilities. In the case of real sample analysis, we used a blood serum sample. A low RSD value (<10 %) suggests the practical use of AuNPs/FTO in real‐life applications. [ABSTRACT FROM AUTHOR]

Amine solvents remain popular in the industries for post combustion carbon dioxide (CO2) capture. Dissociation constant of basic amine solvents plays significant role to influence the CO2 absorption. It is thus important to study the dissociation of new amine solvents for assessing their viability for CO2 capture. In the present work, potentiometric titration method is employed to determine the dissociation constants of dibasic (e. g. Piperazine (PZ), 1‐methyl piperazine (1‐MPZ) and tribasic amines (1‐(2‐aminoethyl‐piperazine) (AEPZ) which could be promising for formulating blended solvent system towards enhancing the rate of CO2 absorption. The estimated dissociation constants for the PZ and 1‐MPZ while match well with reported results, the dissociation constants for AEPZ has been determined newly here within the temperature range 298—318 K. In addition, the structural geometric parameters and Natural Bond Order (NBO) calculations of the amine solvents are performed based on Density Functional Theory (DFT). The NBO calculations predict charge distribution on the nitrogen and other elements, and envisage its effect on the pKa values of the amines. Further, potential energy surface (PES) scanning calculations are performed for AEPZ to explain it's ring inversion which is responsible for obtaining a single pKa value in experimental studies. [ABSTRACT FROM AUTHOR]

The syntheses of two macrocycles containing original imidazothiadiazole heterocycles are presented. The protonation constants of the ligands have been determined by potentiometry and photophysical measurements. The photophysical properties of the corresponding Tb3+ complexes have been analyzed and the sensitization of the Tb3+ by the heterocyclic moiety demonstrated with modest quantum yields. The corresponding Gd3+ complexes are monohydrated and display higher relaxivities than GdDOTA, which could be explained by the larger size of these complexes. The different substitutions on the heterocycle do not affect strongly the protonation constants of the ligand, the quantum yield, water exchange rate or relaxation properties of the system. [ABSTRACT FROM AUTHOR]

The fabrication of cathodes with carbonized Agave tequilana bagasse for Li–S batteries is performed for the first time. Three porous carbonaceous structures are developed and studied to elucidate the best carbon textural properties in terms of their surface area and pore size distribution: hierarchical porosity, highly microporous, and nonporous material, for sulfur hosting in Li–S cathodes. N2 physorption, scanning electron microscopy, infrared spectroscopy, and potentiometric titrations analysis are performed to determine the textural, morphology, and physicochemical properties. The fabricated coin cells, CR2032, with cathodes made of mesoporous carbons, display a high discharge current (≈1600 mAh g−1), superior performance, and cyclability up to 250 cycles. The performance of batteries is found to be strongly influenced by surface area and pore size of the carbon materials. The carbonized tequila bagasse hosting sulfur can be very useful to fabricate cathodes for Li–S batteries with high initial capacity and cycling stability. [ABSTRACT FROM AUTHOR]

In this paper, a simple, sensitive, and precise flow injection system was optimized and applied to ascorbic acid determination with a carbon paste electrode modified with the Schiff base copper complex. The modified sensor showed increased sensitivity toward ascorbic acid oxidation with a decrease of oxidation potential by 200 mV. Under optimized flow parameters, working potential, gasket thickness, sample and reaction coil volumes, and flow rate, the developed flow system gave a linear response from 5 to 75 μmol/L of ascorbic acid. The calculated limit of detection was 4.5 μmol/L, calculated as 3σ/s which corresponds to the absolute value of 40 ng for the 50 μL sample coil. The precision for six consecutive injections of 5 and 75 μmol/L ascorbic acid solutions was determined as a relative standard deviation of 5.8 % and 1.5 %, respectively. The flow injection system enabled up to 120 analyses per hour. An optimized flow system was applied to the determination of ascorbic acid in dietary supplements, after simple preparation. [ABSTRACT FROM AUTHOR]

Modern potentiometric sensors based on polymeric membrane ion‐selective electrodes (ISEs) have achieved new breakthroughs in sensitivity, selectivity, and stability and have extended applications in environmental surveillance, medical diagnostics, and industrial analysis. Moreover, nonclassical potentiometry shows promise for many applications and opens up new opportunities for potentiometric biosensing. Here, we aim to provide a concept to summarize advances over the past decade in the development of potentiometric biosensors with polymeric membrane ISEs. This Concept article articulates sensing mechanisms based on non‐equilibrium measurement techniques. In particular, we emphasize new trends in potentiometric biosensing based on attractive dynamic approaches. Representative examples are selected to illustrate key applications under zero‐current conditions and stimulus‐controlled modes. More importantly, fruitful information obtained from non‐equilibrium measurements with dynamic responses can be useful for artificial intelligence (AI). The combination of ISEs with advanced AI techniques for effective data processing is also discussed. We hope that this Concept will illustrate the great possibilities offered by non‐equilibrium measurement techniques and AI in potentiometric biosensing and encourage further innovations in this exciting field. [ABSTRACT FROM AUTHOR]

In order to deepen the understanding of the role of transition metal oxides in electron transfer at the electrochemical interface, the performance of ZnxNi1−xFe2O4 (x = 0, 0.2, 0.4, 0.6, 0.8, 1) nanomaterials in electrochemical sensing is studied. Nanomaterials are synthesized by simple autocombustion synthesis procedure. Field‐emission scanning electron microscopy characterization shows that the particles have a size between 30 and 70 nm with an average crystallite size between 24 and 35 nm. The bandgap energies of the nanomaterials, as estimated by UV–vis experiments, are in the 2.32–2.56 eV range. The valence band maximum is evaluated using X‐ray photoelectron spectroscopy and the position of the conduction band minimum is estimated. The ZnFe2O4 sensor has the best performances: highest rate constant (13.1 ± 2.8 ms−1), lowest peak‐to‐peak separation (386 ± 2 mV), and highest sensitivity (37.75 ± 0.17 μA mM−1). Its limit of detection (7.94 ± 0.04 μM) is second best, and its sensitivity is more than twice the sensitivity of the bare sensor (16.7 ± 0.9 μA mM−1). Nanomaterials energy bands mapping with the experimental redox potentials is performed to predict the electron transfer at the electrochemical interface, and the importance of surface states/defects is highlighted in the electron transfer mechanism. [ABSTRACT FROM AUTHOR]

It is important to accurately control the setting of concrete and mortars. Functional admixtures such as hydroxy carboxylic acids can modify the hydration mechanism by influencing the dissolution of clinker phases and the crystallization of hydrate phases. While the crystallization of phases like CaCO3 under the influence of various additives has been studied intensively, there is substantially less understanding with regard to the main products of cement hydration, i.e., C‐S‐H, portlandite, ettringite, etc. In this work a potentiometry based setup was used to study the influence of succinic, tartaric, and citric acid on the nucleation and growth of portlandite and C‐S‐H. We found that the investigated molecules not only lead to a significant delay in nucleation by stabilization of prenucleation clusters, but also show a strong influence on the process of crystal growth. Further the effect of these molecules on the hydration reaction of tricalcium silicate was examined using ex‐situ calorimetry. We found a decent retarding effect on this reaction, even when there was almost no observable effect on the nucleation process in the previous experiments. [ABSTRACT FROM AUTHOR]

A fast HPLC method was developed to study the hydrophobicity extent of pharmaceutically relevant molecular fragments. By this strategy, the reduced amount of sample available for physico‐chemical evaluations in early‐phase drug discovery programs does not represent a limiting factor. The sixteen acid fragments investigated were previously synthesized also determining potentiometrically their experimental log D values. For four fragments it was not possible to determine such property since their values were outside of the instrumental working range (2 < pKa < 12). An RP‐HPLC method was therefore optimized. For each scrutinized method, some derived chromatographic indices were calculated, and Pearson's correlation coefficient (r) allowed to select the so‐called "φ0 index" as the best correlating with the log D. The wspH${}_w^spH$ was fixed at 3.5 and a modification of some variables [organic modifier (methanol vs. ACN), stationary phase (octyl vs. octadecyl), presence/absence of the additives n‐octanol, n‐butylamine, and n‐octylamine], allowed to select the best correlation conditions, producing a r = 0.94 (p < 0.001). Importantly, the φ0 index enabled the estimation of log D values for four fragments which were unattainable by potentiometric titration. Moreover, a series of molecular descriptors were calculated to identify the chemical characteristics of the fragments explaining the obtained φ0. The number of hydrogen bond donors and the index of cohesive interaction correlated with the experimental data. [ABSTRACT FROM AUTHOR]

Background: Ionophores in the composition of potentiometric ion‐selective electrodes interact directly with the analyte ion and enable the determination of ionic species in various samples. Objectives: In this study, a novel ion‐selective electrode based on 5‐bromosalicylaldehyde thiosemicarbazone was developed for the selective determination of Cr3+ ions. Methods: The optimum electrode composition contained ionophore, poly (vinyl chloride) (PVC), bis (2‐ethylhexyl) sebacate (BEHS) and potassium tetrakis (p‐chlorophenyl) borate (KTpClPB) in ratios of 4.0: 61.0: 34.0: 1.0 (mg), respectively. Potential measurements were performed using a computer‐controlled multi‐channel potentiometric measurement system. Results: The developed Cr (III)‐selective electrode exhibited a low detection limit of 3.96 × 10−6 M over a wide concentration range of 1.0 × 10−5 – 1.0 × 10−1 M (R2: 0.9979). The electrode exhibited good selectivity towards Cr3+ ions among metal ions with different charges. The chromium (III)‐selective electrode, which exhibited highly reproducible results in three different concentration ranges, also had a very fast response time of 5 s. Conclusions: The developed Cr (III)‐selective electrode were successfully performed in various beverage samples. As a result, the proposed electrode can be an alternative to other analytical methods in the analysis of Cr3+ ions. [ABSTRACT FROM AUTHOR]

The use of solid‐contact ion‐selective electrodes (ISEs) is of interest to many clinical, environmental, and industrial applications. However, upon extended exposure to samples and under thermal and mechanical stress, adhesion between these membranes and underlying substrates often weakens gradually. Eventually, this results in the formation of a water layer at the interface to the underlying electron conductor and in delamination of the membrane from the electrode body, both major limitations to long‐term monitoring. To prevent these problems without increasing the complexity of design with a mechanical attachment, we use photo‐induced graft polymerization to simultaneously attach ionophore‐doped crosslinked poly(decyl methacrylate) sensing membranes covalently both to a high surface area carbon as ion‐to‐electron transducer and to inert polymeric electrode body materials (i.e., polypropylene and poly(ethylene‐co‐tetrafluoroethylene)). The sensors provide high reproducibility (standard deviation of E0 of 0.2 mV), long‐term stability (potential drift 7 μV h−1 over 260 h), and resistance to sterilization in an autoclave (121 °C, 2.0 atm for 30 min). For this work, a covalently attached H+ selective ionophore was used to prepare pH sensors with advantages over conventional pH glass electrodes, but similar use of other ionophores makes this approach suitable to the fabrication of ISEs for a variety of analytes. [ABSTRACT FROM AUTHOR]

The potentiometric titration of a carbonate mixture or an acetate solution is a common experiment in analytical laboratories. Typically, a glass electrode combined with a calomel or Ag/AgCl reference electrode is used to locate the equivalence points in neutralization titrations. The dissociation constants of weak acids and bases can be calculated from the pH at the half‐neutralization point. Recently, a new commercial product for measuring pH has been developed. This novel acid–base detection strip is a single‐use sensor that requires neither storage in a preservation liquid nor calibration prior to use. This study examined its suitability for the continuous monitoring of pH changes in potentiometric titrations of carbonate mixtures, acetate solutions, or ammonia solutions. There were no significant differences in the concentrations of solutions tested using a glass electrode and a pH test strip. The pKa, pKb, and pH values determined using the two systems differed by less than 5%. The results confirmed that the pH strips are suitable for continuously monitoring pH changes during neutralization titrations. However, the strips can only be used once. [ABSTRACT FROM AUTHOR]

All vanadium flow batteries (VFBs) are considered one of the most promising large‐scale energy storage technology, but restricts by the high manufacturing cost of V3.5+ electrolytes using the current electrolysis method. Here, a bifunctional liquid fuel cell is designed and proposed to produce V3.5+ electrolytes and generate power energy by using formic acid as fuels and V4+ as oxidants. Compared with the traditional electrolysis method, this method not only does not consume additional electric energy, but also can output electric energy. Therefore, the process cost of producing V3.5+ electrolytes is reduced by 16.3%. This fuel cell has a maximum power of 0.276 mW cm−2 at an operating current of 1.75 mA cm−2. Ultraviolet–visible spectrum and potentiometric titration identify the oxidation state of prepared vanadium electrolytes is 3.48 ± 0.06, close to the ideal 3.5. VFBs with prepared V3.5+ electrolytes deliver similar energy conversion efficiency and superior capacity retention to that with commercial V3.5+ electrolytes. This work proposes a simple and practical strategy to prepare V3.5+ electrolytes. [ABSTRACT FROM AUTHOR]

Facile, lightweight, and sustainable aerogels have been a growing interest in their applications as support matrixes in the current environmental and energy challenges. In this study, a cellulose aerogel (CA) is fabricated using a homogeneous dispersion of cellulose fibers in an alkali‐urea aqueous solution and a carbon nanotube ink (CNT‐ink) to increase its electrical and conductive behavior in a potentiometric analysis. The physicochemical and morphological properties of the resultant composite aerogels (CA, CA1, and CA2) are investigated by thermal, water resistance, mechanical, FTIR, and SEM analysis. The prepared material exhibits a structured solid network that is visualized through SEM in which fibers are functionalized with CNTs. The results from compressive tests reveal that CA2 has excellent mechanical properties. A saturated CA with CNT‐ink can turn on a white LED and potentiometric measurements by preparing an aerogel‐based ion‐selective electrode (CA2 ‐ ISE) with a potassium ion‐selective membrane (K+ − ISM) reveal good sensitivity at room temperature for the detection in a specific electrolyte solution. [ABSTRACT FROM AUTHOR]

This work presents a potentiometric approach for the detection of two cathinone derivatives, namely mephedrone (4‐MMC) and clephedrone (4‐CMC). Contrary to neutral‐carriers (dibenzo‐18‐crown‐6‐ether and calix[4]arene), cation‐exchanger (tetraphenylborate sodium) as active component of ion‐selective membrane showed near‐Nernstian response (+47 mV/decade from 1.7 ⋅ 10−6 to 5.6 ⋅ 10−4 mol l−1) and selectivity for 4‐MMC in oral fluids (OF). The agreement between the quantitative results obtained with the potentiometric approach and the HPLC/MS‐MS method determination of 4‐MMC in OF shows the potential of the proposed potentiometric approach for forensic analysis. [ABSTRACT FROM AUTHOR]

Recently a novel chronopotentiometric method has been introduced that was found useful for assessing antioxidant activity. In our experiments, the performance of chemically modified working electrodes made of different pencil materials were tested in the novel method. Redox mediator film of Meldola Blue was formed on electrode surfaces. The stability of the film, the number of molecules structuring it has been studied. In antioxidant measurements, controlled potential oxidation of the mediator was made followed by recording the open cell potential in time. The initial slope of this was used as analytical signal. Results proved applicability of the pencil probes. [ABSTRACT FROM AUTHOR]

In this study, seven new and known 1,4‐naphthoquinone acyl thiourea hybrids were synthesized and their molecular structures were confirmed by various analytical methods. These derivatives were tested for their anti‐inflammatory potential on the murine macrophages. Pro‐inflammatory cytokine production levels and cell viabilities were compared between the groups and with LPS positive control groups to determine the most potent anti‐inflammatory drug candidate. Our results suggest that these derivatives had anti‐inflammatory activity without exerting major cytotoxicity. Their future evaluation in inflammatory and autoimmune disease settings will be crucial for their possible utilization in the clinical setting. The acid dissociation constants of synthesized hybrids 1–7 were determined potentiometrically at 25.0±0.1 °C, at an ionic strength of 0.1 M NaCl in 20 % (v/v) DMSO – water hydro‐organic solvent mixture in an acidic medium. Three acid dissociation constants were calculated for each hybrid with the HYPERQUAD computer program using the data obtained as a result of potentiometric titrations under the specified conditions. [ABSTRACT FROM AUTHOR]

Diaryliodonium salts are used in organic chemistry, materials science and pharmaceutical chemistry. For the quantitative analysis of diaryliodonium salts, only instrumentally demanding techniques requiring highly skilled operators are available. Surprisingly, no titration method taking advantage of the oxidising ability of diaryliodonium is available in the literature. In the present work, a titration method for the determination of diaryliodonium salts is presented. It is based on the reaction of diaryliodonium species with ascorbic acid, whose excess is subsequently determined by means of iodometric potentiometric titration. Application of the protocol to various diaryliodonium salts revealed the scope and limitations of the method. [ABSTRACT FROM AUTHOR]

BACKGROUND: Epilepsy is a neurological disorder and its treatment is carried out with anti–epileptic drugs. Carbamazepine has been in use since 1965, as a safe and effective anti–epileptic agent. In this paper, a poly(vinyl chloride) (PVC) membrane carbamazepine selective potentiometric sensor was developed for the determination of carbamazepine in pharmaceutical formulations. Carbamazepine–tetraphenylborate (CBZ–TPB) ion−pair was synthesized as an electroactive component and PVC membrane sensors were prepared with different CBZ–TPB ratios. The membrane with the best analytical properties was determined as the one with 2.0% CBZ–TPB ion–pair, 33.0% PVC and 65.0% o–nitrophenyl octyl ether (o–NPOE). RESULTS: The proposed sensor exhibited linear responses over the concentration range 1.0 × 10−5 – 1.0 × 10−2 mol L−1 (R2 = 0.999). The limit of detection was 9.60 × 10−6 mol L−1. The developed sensor showed high selectivity against carbamazepine over some ionic species investigated and also over other anti–epileptic drugs. The potentiometric response of the sensor was not affected by pH in the wide pH range of 4.0–9.0 and the response was fast, at ≈10s. CONCLUSION: The fabricated carbamazepine–selective sensor was applied for the determination of carbamazepine contents of some pharmaceutical formulations. The potentiometric measurement results for the pharmaceutical formulations gave results with good agreement with data obtained using UV–visible spectroscopy. As a result, the developed carbamazepine selective potentiometric sensor can be considered as an alternative to other analytical methods for the determination of carbamazepine in pharmaceutical samples. © 2022 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

The present investigation deals with the development of a polyvinyl chloride (PVC) based potentiometric sensor for Eu(III) containing N,N,N',N'‐tetrapentyl diglycolamide (TPDGA) as ionophore, 2‐nitrophenyl octylether (NPOE) as plasticizer and sodium tetraphenylborate (NaTPB) as ionic additive. The membrane with 8.7 % TPDGA, 29.7 % PVC, 59.0 % NPOE, 2.5 % NaTPB exhibited a linear response behaviour from 1.5×10−6 m to 1.1×10−2 m Eu(III) with a slope of 23.4±0.3 mV/decade and a limit of detection (LOD) of 1.2×10−6 m. The sensor showed fast response times (<5 s) and a lifetime of two months. It showed good tolerance for monovalent/divalent interfering ions and moderate/poor tolerance for trivalent ions. The membrane was characterized using photoluminesce (PL) spectroscopy which suggested NPOE can alter the nature of species in the membrane and evidence the presence of two species. The membrane can be used as an indicator electrode for the potentiometric titration of Eu(III) and in the estimation of europium in the synthetic and laboratory bearing waste which compared well with the x‐ray fluorescene (XRF) results. [ABSTRACT FROM AUTHOR]

Serotonin (5‐HT) is a major neurotransmitter broadly involved in many aspects of feeling and behavior. Although its electro‐activity makes it a promising candidate for electrochemical sensing, the persistent generation of fouling layers on the electrode by its oxidation products presents a hurdle for reliable sensing. Here, we present a fouling‐free 5‐HT sensor based on galvanic redox potentiometry. The sensor efficiently minimizes electrode fouling as revealed by in situ Raman spectroscopy, ensuring a less than 3 % signal change in a 2 hour continuous experiment, whereas amperometric sensors losing 90 % within 30 min. Most importantly, the sensor is highly amenable for in vivo studies, permitting real‐time 5‐HT monitoring, and supporting the mechanism associated with serotonin release in brain. Our system offers an effective way for sensing different neurochemicals having significant fouling issues, thus facilitating the molecular‐level understanding of brain function. [ABSTRACT FROM AUTHOR]

Typically, ion‐selective electrodes used in current triggered electrochemical sensing apply a conducting polymer layer covered with an ion‐selective membrane. In this work we propose an ion‐selective membrane containing a dispersed conducting polymer. Thus obtained system allows elimination of the Achilles hell of heterogeneous ion‐selective membranes containing solid particulates dispersed within the ion‐selective polymeric membrane. The herein proposed system, even for high conducting polymer loading equal to 5 % w/w, is characterized with insensitivity towards redox interferences, as well as potentiometric detection limits, selectivity well comparable with that for other ion‐selective electrodes constructions. Under voltammetric conditions, with increasing loading of the conducting polymer in the membrane cathodic peak potentials are shifted towards more negative values, yet the linear dependence of the peak potential on logarithm of concentration of the analyte in the solution is preserved. [ABSTRACT FROM AUTHOR]

A new stoichiometric FTIR Base Number (BN) method of significant utility and analytical benefit to the tribology sector has been developed, providing ASTM D4739‐comparable BN results in lieu of titration in a fraction of the time. Thirty‐six new/in‐service oils analysed by both methods were linearly related with a between‐method accuracy of ~±1.0 BN and a within‐FTIR method reproducibility of ~±0.50 BN. Acid pKa differences and the comparative similarity of the FTIR results to HCl titration are discussed, including analytical benefits. It provides a rapid means of producing quality ASTM‐comparable results, taking ~1 min/sample for spectral analysis versus 30–40 min for potentiometric titration. Method protocols are best suited to an open architecture FTIR accessory but can be readily adapted to flow cell equipped FTIRs. As structured, ASTM‐like results are obtained rapidly with a major analytical environmental/maintenance footprint reduction, being ideally suited for in‐service lubricant or research labs analysing 20–50 samples/day. [ABSTRACT FROM AUTHOR]

Nitrate sensing is an important application for potentiometry in environmental applications. Its recognition is by ion‐exchangers whose selectivity is governed by the lipophilicity of the ions in solution. Yet, considerable research efforts have been dedicated to the development of such ionophores and some have already been commercialized. This work examines two commercially available nitrate ionophores, nitrate ionophores V and VI, and compares their performance with widely used ion‐exchangers by determining the resulting membrane selectivity and complexation to nitrate. Unfortunately, adding a nitrate ionophore to the membrane did not result in improved selectivity. Sandwich membrane experiments indicated that binding interaction is too weak to be measurable, with a logarithmic formation constant of just 1.36±0.14 for ionophore V with nitrate. Ways to improve the reporting of relevant data are suggested. [ABSTRACT FROM AUTHOR]

A single nanoparticle (NP) attached to a nanoelectrode is a very useful system in understanding the relationship between the size of nanoparticles and their electrochemical properties. In this study, a single Au NP was spontaneously formed on a Pt nanoelectrode. The potential measured on such a system can be employed to study the effect of size of an Au nanoparticle on the Nernst potential of the reaction, AuCl4− +3e → Au(s) +4Cl−. Moreover, the nucleation period and the growth period can be distinguished from the potential graph, and the nucleation rate of the spontaneously formed Au NP can be evaluated. [ABSTRACT FROM AUTHOR]

Bioelectronic sensors that report charge changes of a biomolecule upon target binding enable direct and sensitive analyte detection but remain a major challenge for potentiometric measurement, mainly due to Debye Length limitations and the need for molecular‐level platforms. Here, we report on a magneto‐controlled potentiometric method to directly and sensitively measure the target‐binding induced charge change of DNA aptamers assembled on magnetic beads using a polymeric membrane potentiometric ion sensor. The potentiometric responses of the negatively charged aptamer, serving as a receptor and reporter, were dynamically controlled and modulated by applying a magnetic field. Based on a potentiometric array, this non‐equilibrium measurement technique combined with deep learning algorithms allows for rapidly and reliably classifying and quantifying diverse small molecules using antibiotics as models. This potentiometric strategy opens new modalities for sensing applications. [ABSTRACT FROM AUTHOR]

This work represents first attempt for potentiometric determination of the most recent antidiabetic; omarigliptin. Three sensors, employing potassium tetrakis (p‐chlorophenyl) borate as a lipophilic cation exchanger, were developed and compared. One liquid contact ion‐selective electrode and two carbon paste‐based solid contact ones, plain one and another one modified with polyaniline nanoparticles, were employed. Performances of fabricated sensors were assessed as per IUPAC recommendations. Incorporation of hydrophobic polyaniline nanoparticles as ion‐to‐electron transducer layer at solid contact/ion‐sensitive membrane interface enhanced sensitivity and stability of the third sensor showing LOD of 2.5×10−7 mol L−1 and slope of 58.57 mV decade−1. The three sensors were applied for omarigliptin determination in presence of its degradation products, in dosage form and spiked human plasma. [ABSTRACT FROM AUTHOR]

Multiplexed solid‐contact ion‐selective electrodes (SCISEs) are fabricated using printed circuit board (PCB) and mesoporous carbon black (MCB) as ion‐to‐electron transducer (solid contact). Four sensor configurations were examined and showed that in addition to MCB, the sensor configuration plays crucial role in the stability of the potential response. The enhanced sensor stability was also linked with suppression of transmembrane flux of water. The sensors exhibited near‐Nernstian sensitivity (58.1 mV/dec for K+ ISEs and −55.1 mV/dec for NO3‐ ISEs), low detection limits (1.5–2.2 μM), and good short‐term stability (∼0.1 mV/min). Sensors can be stored dry and used without preconditioning. This work demonstrates a promising approach to combining PCB technology and carbon black for large‐scale production of low cost ISEs for point‐of‐care testing, wearables, or in situ field measurements. [ABSTRACT FROM AUTHOR]

Peptide nucleic acids (PNAs) are neutral mimics of natural DNA and RNA biopolymers that have caught the attention of researchers working on the identification of specific sequences of nucleobases in DNA/RNA strands. For this purpose, specific analytical protocols need to be developed to optimize the nucleic acid recognition ability of PNAs, exploiting both the high intrinsic affinity of PNA/DNA(RNA) couples as well as suitable markers, either linked to the PNA backbone or properly interacting with it in the working medium. In this context, the paper reports on phthalimide and 4‐nitrophthalimide as two cheap, metal‐free electroactive markers covalently bound to the pseudo‐peptide backbone of a PNA decamer. After a preliminary characterization of the markers, as such and in PNA conjugates, attention has been moved toward the optimization of the detectability of the labeled PNA decamers in aqueous solutions. Exploiting the potentiometric stripping analysis on hanging mercury drop electrode it has been possible to reach satisfactory detection limits of ca. 10 nM avoiding the use of expensive transition metal complexes as labels and/or of co‐reagents. [ABSTRACT FROM AUTHOR]

Isomerization of d‐glucose (Glc) into d‐fructose (Fru) is of great importance for food sector as well as for valorization of lignocellulosic biomass. Soluble and solid bases exhibit high catalytic activity for the isomerization. Here, we report a salt effect on the base‐catalyzed aqueous‐phase Glc‐Fru isomerization. Addition of soluble salts (Na2SO4, NaNO3, K2SO4, and NaCl) results in an increased apparent reaction rate (factors of 1.5 to 6). The salt effect was observed both in the presence of soluble base NaOH at constant pH value and solid bases MgO, Li3PO4, and Mg−Al hydrotalcite. Apparent activation energy and UV absorption spectra were not significantly influenced by addition of salts. Potentiometric titration showed that the acidity constants of the saccharides increase in the presence of electrolytes. Since the rate of the isomerization depends on the thermodynamic acidity constant of Glc, the isomerization is accelerated by the presence of electrolytes. [ABSTRACT FROM AUTHOR]

Higher stability of tetrahedral hydroxyboronate cyclic esters of 1,2‐diols in comparison with the respective trigonal esters and the associated increased acidity of the trigonal esters in comparison with free boronic acids are well‐known and important aspects of the thermodynamics of boronate ester formation usually attributed to the strain in O–B–O angle created in the trigonal esters and released in the tetrahedral hydroxyboronates. The stability constants of tetrahedral (Ktet) and trigonal (Ktrig) boronate esters of several aliphatic and aromatic 1,2‐ and 1,3‐diols with a series of five boronic acids of variable acidity were determined by potentiometric titrations in water. The ratio Ktet/Ktrig varies from ~10 for cis‐1,2‐cyclopentanediol to ~104 for catechol entirely due to the increase in Ktet for more acidic diols and is weakly affected by the acidity of boronic acids. Analysis of DFT minimized structures of trigonal and tetrahedral esters of phenylboronic acid with cis‐1,2‐cyclopentanediol, 1,4‐anhydroerythritol, and catechol demonstrates the absence of postulated strain release in the tetrahedral esters. A global analysis of new and previously reported relevant data on Ktet, Ktrig, and Ktet/Ktrig values for 1,2‐ and 1,3‐diols and different boronic acids in terms of the Brønsted‐type correlations with pKa values of the reaction components shows that Ktet/Ktrig values vary in a wide range from ~1 to ~106, and this variation can be satisfactorily explained by the stabilization of tetrahedral hydroxyboronate cyclic esters by more acidic diols without invoking of the strain release effect. [ABSTRACT FROM AUTHOR]

Hexachlorobenzene (HCB) is a pollutant still found in the environment despite being widely banned. Considering that basidiomycetes are useful to degrade a variety of organochlorinated pollutants, we therefore report the influence of HCB on the ligninolytic enzymatic system of Deconica castanella. The inoculum was prepared with sugarcane bagasse and soybean flour and was added in soil with and without HCB (2000 mg kg soil−1), 5% emulsion containing soybean oil and Tween 20 at proportion 9:1, v:v; with 70% moisture at 25°C. Fungal biomass was quantified by widely acknowledged growth biomarker ergosterol. The extraction of the enzymatic complex was performed and laccase, Mn‐dependent peroxidase (MnP), and lignin peroxidase (LiP) activities were determined. Furthermore, HCB and its metabolites were quantified by gas chromatography and chlorides by potentiometric titration. Results evidenced that HCB did not interfere in fungal growth, though the only detected enzymatic activity was laccase. MnP and Lip were not detected during D. castanella growth in soil. The peak of laccase enzymatic activity occurred in the presence of HCB. In addition, the laccase exhibited thermostability. Therefore, we hereby shed light on the role of laccase in the degradation of HCB by an efficient low‐cost and environmentally safe detoxification mechanism. [ABSTRACT FROM AUTHOR]

Eugenol is a compound with well‐known bioactivity; however, its volatility limits its therapeutic applicability. In the present study, carboxymethylated xanthan gum (CXG) is synthesized and characterized regarding its degree of substitution (DS) by potentiometric titration and by infrared spectroscopy (FTIR). Oil‐in‐water xanthan gum‐based nanoemulsions enriched with eugenol have been prepared in variable conditions, using XG (xanthan gum) and CXG as matrices to produce a stable formulation with an effective ovicidal activity. Physical–chemical characterizations are performed, besides ovicidal activity on Haemonchus contortus, the main gastrointestinal nematode infecting and affecting small ruminants. FTIR results indicate the insertion of the carboxymethyl groups in the structure of xanthan gum through the peaks at 1100 and 1600 cm−1, and titration shows a DS of 1.25 for CXG. XG and CXG emulsions present stability over 30 days and encapsulation efficiency higher than 50%. The CXG2 emulsion (CXG:oil:tween 4:2:1) shows better stability concerning the lower zeta potential value, and the morphology shows domains with smaller sizes in the range of 1.41 µm. The evaluated nanoemulsions show ovicidal activity against H. contortus, which encourages their future use as an alternative to control haemonchosis in sheep and goats. [ABSTRACT FROM AUTHOR]

In current research, we determined the stability constants and kinetic properties of Bi3+ complexes with the benzoazacrown ligand H4BATA along with the H4DOTA ligand. Correct determination of the stability constants is possible when equilibrium with the free forms of the cation is observed. Unlike potentiometric titration, it is possible to apply the free‐ion selective radiotracer extraction (FISRE) method with highly stable complexes at low pH values, where the true equilibrium with the free cation forms in the solution is achieved. FISRE clarified the stability constants of Bi3+ complexes with H4BATA towards higher values. According to the UV spectroscopy data, the H4BATA ligand binds Bi3+ at room temperature within a few minutes at pH 1. We also defined the acid‐assisted mechanism of complex dissociation, where monoprotonated and deprotonated forms of the complex were found to be inert. In summary, the H4BATA ligand is highly suitable for use as a component of bismuth‐based radiopharmaceuticals. [ABSTRACT FROM AUTHOR]

Recently, mortality linked to the intake of the antidepressant mirtazapine (MTZ) together with other drugs has been recently detected, and measuring the MTZ concentration in biological fluids has become crucial. The proposed electrode is thought to be the first potentiometric carbon paste electrode for quantifying MTZ in various biological matrices. It is based on the covalent polymerization of the aniline monomers onto the surface of the multi‐walled carbon nanotubes (MWCNTs) /TiO2 nanocomposite to be applied as an ion‐to‐electron transducer element with 18‐crown‐6‐ether as a recognition element. The MWCNTs/TiO2/Polyaniline (PANI) composite was characterized by XRD and FT‐IR. The electrode demonstrated a wide linearity range of 1×10−7 M to 1×10−2 M with a Nernstian slope of 59.76±1.55 mV/concentration decade and a LOD of 3.2×10−8 M. It was successfully applied for the determination of MTZ in spiked plasma, urine, and artificial cerebrospinal fluid without any significant interference from matrix components, with average recovery, ranged from 97.91 % to 99.31 %. [ABSTRACT FROM AUTHOR]

Conduction layer plays an important role in ion‐selective electrodes (ISEs) with solid‐state transduction. Herein, a lead ISE was prepared with Ti3C2 as the conductive layer, which has less water film and good anti‐interference ability to O2, CO2 and light. Concentration of lead ions can be quickly determined by detecting the electromotive force of the galvanic cell. In 10−3–10−7 M, the Nernst slope is found to be 28.3±1.02 mV/decade. And the detection limit is 4.4×10−8 M (n=3). It indicates that Ti3C2 is suitable for the conductive layer in solid ISEs. [ABSTRACT FROM AUTHOR]

Cover picture provided by Dr. Elena Benito‐Peña and Dr. Susana Campuzano. Electroanalysis covers all branches of electroanalytical chemistry, including both fundamental and application papers as well as reviews dealing with analytical voltammetry, potentiometry, new electrochemical sensors and detection schemes, nanoscale electrochemistry, advanced electromaterials, nanobioelectronics, point‐of‐care diagnostics, wearable sensors, and practical applications.. [Extracted from the article]

In this study, a novel PVC‐based membrane containing (E)‐2‐(1‐(4‐(3‐(4‐chlorophenyl)ureido)phenyl)ethylidene)hydrazine carbothioamide (5) as an electroactive component (ionophore) along with potassium tetrakis (p‐chlorophenyl) borate (KTpClPB) and bis(2‐ethylhexyl)adipate (DEHA) in the ratio 4.0 : 32.0 : 1.0 : 63.0 (ionophore:PVC:KTpClPB:DEHA) (w/w) was used to develop a lead(II)‐selective potentiometric sensor. The sensor exhibited a Nernstian response over a wide concentration range from 1.0×10−5 to 1.0×10−1 mol L−1 with a slope of 28.0±2.0 mV/decade, and a detection limit of 1.65×10−6 mol L−1. It displayed very good selectivity towards Pb(II) ions over other cationic species. The lead(II)‐selective sensor showed a fast response time of 5 s, good repeatability, and it worked in the broad pH range of 5.0–11.0. The sensor could be used as an indicator electrode in the quantification of Pb(II) by potentiometric titration against ethylenediaminetetraacetic acid (EDTA). In addition, this sensor was applied for the direct determination of Pb(II) in different water samples including spring water, purification water, commercial water, waste water and in a waste battery sample. [ABSTRACT FROM AUTHOR]

A new chemically modified potentiometric carbon paste electrode was fabricated based on incorporation of the ion association complex of sitagliptin‐phosphotungstate to determine sitagliptin. The proposed sensor displayed a Nernstian slope of 59.4 mV/decade for sitagliptin over a concentration range of 1.7×10−8 to 2.2×10−5 M and a detection limit of 9.1×10−9 M. It represented the advantages of fast response, long lifetime and, most importantly, excellent selectivity for sitagliptin versus a wide variety of usual inorganic cations and also biological species such as amino acids and sugars. The temperature dependence of sensor potential was examined, and it was figured out that the sensor has a low thermal coefficient in the temperature range of 15–55 °C. The sensor was applied to determine sitagliptin in pharmaceutical tablets, milk and blood serum samples. The obtained suitable recoveries and relative standard deviations confirmed that the developed sensor could be precisely applied to determine sitagliptin in real samples. [ABSTRACT FROM AUTHOR]

This study outlines the improvement on anticorrosion behavior of chitosan‐based sol‐gel coatings on carbon steel surface obtained for high deacetylation degree values of this natural biopolymer. Important economic losses in major industries represent a problem due to corrosion of metals in aggressive medium, such as carbon steel, which is widely used due to its hardness, durability, ductility, low cost, handiness. Therefore, non‐toxic, cost‐effective, and eco‐friendly strategies are needed to protect metallic surface of steel. Against this background, the anticorrosion coating performance of chitosan, from three different commercial sources, as a single component, on carbon steel in chloride solutions is investigated using electrochemical impedance spectroscopy technique. The present study is performed to evaluate the corrosion protective abilities of chitosan in order to determine the relationship with its deacetylation degree (DDA), evaluated by potentiometric titration, a simple and reliable method. Depending on the DDA, the experimental results indicate that there is a remarkable difference between different chitosan samples regarding the value of the charge transfer resistance of coating on steel. [ABSTRACT FROM AUTHOR]

In this study, a simple and highly selective potentiometric sensor has been developed for the determination of cobalt(II) ions based on a poly(vinly chloride) (PVC) membrane. As an ionophore, a hydrazone derivative molecule (3) was synthesized for the first time, and its characterization was completed using NMR, FT‐IR and Q‐TOF spectroscopic techniques. The developed sensor works well in the linear concentration range of 1.0×10−6–1.0×10−1 Μ with Nernstian slope of 28.6±1.7 mV/decade of activity. The developed cobalt(II)–selective sensor has a low detection limit of 3.09×10−7 Μ, and a very fast response time of 5 seconds. The sensor, which exhibits a highly selective behaviour towards cobalt(II) ions compared to other metal cations, works in the pH range of 6.0–10.0 without being affected by changes in pH. The developed sensor could be used as an indicator electrode in potentiometric titration of Co(II) ions with EDTA. Finally, the developed cobalt(II)‐selective sensor was successfully used for the determination of Co(II) in various water samples. [ABSTRACT FROM AUTHOR]

This work demonstrates the analytical applicability of single ion‐selective membranes (ISMs) and potentiometric sensor array to distinguish and detect cathinone derivatives. Potentiometric data from ISMs based on cation exchanger and varying content of calix[4]arene derivative were processed by principal component analysis (PCA). Such a combination of methods allowed discriminating various individual synthetic cathinones and their recognition from the mixture comprising primary amines (substituted amphetamines+aminoindane). Analytical parameters of ISM containing 1wt % of calix[4]arene derivative were sufficient to detect 1.0×10−4 mol.l−1 1‐(4‐fluorophenyl)‐2‐(ethylamino)butan‐1‐one and 2‐(methylamino)‐1‐phenylbutan‐1‐one (buphedrone) in both model and saliva samples. [ABSTRACT FROM AUTHOR]

A novel poly(vinyl chloride; PVC) membrane‐based Cu(II)–selective sensor has been developed using synthesized 5,10,15,20‐tetrakis(4‐methoxycarbonylphenyl)porphyrin as an ionophore. The Cu(II)–selective sensor exhibits a Nernstian response for Cu(II) ion over a wide concentration range of 1.0 × 10−5 to 1.0 × 10−1 mol L−1 with the slope of 27.0 ± 2.5 mV/decade, and a lower limit of detection of 1.88 × 10−6 mol L−1. The novel sensor shows good repeatability and high selectivity for Cu(II) ions over other mono‐, bi‐ and trivalent cations. The sensor potential response remains unaffected by pH in the range of 4.4–10.6 and exhibits a fast response time of less than 10s. Finally the developed Cu(II)–selective sensor has been successfully used as an indicator electrode in the potentiometric titration of Cu2+ against ethylenediaminetetraacetic acid and also in the determination of Cu(II) ion concentration in different water and beverage samples. [ABSTRACT FROM AUTHOR]

Poly‐N‐n‐propylacrylamide based microgels with embedded Pd‐nanoparticles are synthesized with varying amounts (5–25 mol%) of methacrylic acid (MAc) comonomer. The microgels are characterized to investigate the influence of the comonomer content on catalytic activity of the hybrid particles. Since the acidity changes significantly upon copolymerization, the incorporated amount and apparent p Ka value of the MAc via potentiometric titration are determined. The thermoresponsive properties of the microgels are characterized by means of photon correlation spectroscopy at pH values of 4 and 10, which correspond to the protonated and deprotonated state of the acidic copolymer according to the determined p Kavalues. MAc shows tremendous influence on the thermoresponsivity of the microgels not only related to the amount of MAc but especially upon change in pH. The prepared microgel systems are subsequently loaded with palladium nanoparticles. Their catalytic activity is investigated by the reduction of 4‐nitrophenol. The catalytic degradation of the educt is monitored via UV–vis spectroscopy and the observed absorbance decay is analyzed by a pseudo‐first order kinetic. Derived reaction rate constants are normalized with respect to the surface area of the palladium nanoparticles, revealing that the charge density and hydrophilicity within the microgel template greatly affect reactivity of embedded nanoparticles. [ABSTRACT FROM AUTHOR]