Chloride-selective Electrode Research Articles

Acylhydrazone-based reversibly photoswitchable ion pair transporter with OFF-ON cotransport activity.

The cellular membrane transport of physiologically important cations and anions is omnipresent and regulates different physiological functions. Whereas a notable number of cation-anion transporters are being developed to transport salts across the membrane, developing an artificial cation-anion symporter with stimulus-responsive activities is an immense obstacle. Herein, for the first time, we report reversibly photoswitchable acylhydrazone-based transporter 2 that has distinctive OFF-ON cation-anion co-transport abilities. The substituent was modified in 1a-1c and 2, to change the to-and-fro movement of the transporter to enhance the ion transport efficiency. Ion transport experiments across the lipid bilayer membrane demonstrate that 1a has the highest transport activity among the series with irreversible photoisomerization properties, whereas 2 has a unique reversible photoisomerization property. A detailed transport study indicated that the E-conformer of compound 2 facilitates Na+/Cl- transport via the symport process by following the carrier mode of ion transport. 23Na NMR and chloride selective electrode assays confirmed the OFF and ON state of ion transport of compound 2 with photoirradiation. An assembly of [(2 E )2 + NaCl] was subjected to geometry optimization to understand the responsible ion binding motif. Geometry optimization followed by the natural bond orbital analysis of 1a Z and 2 Z demonstrated that 1a Z forms comparatively stronger intramolecular H-bonding than 2 Z , making it accessible for reversible photoisomerization.

Correlation between chemical composition of enamel and oral fluid in patients with intact teeth and cervical pathology

Annotation. Cervical pathology of teeth is widespread and polyetiological, saliva plays an important role in its occurrence and progression. The aim of the study is to determine the chemical composition of oral fluid in patients with cervical caries, wedge-shaped defect, intact hard dental tissues; establish correlations between oral fluid and cervical enamel. In this regard 33 patients were divided depending on the condition of hard dental tissues and there were determined: Сa2+, РО43-, SO42-, Na+, К+, Al3+, Mg2+, Zn2+ – by spectrometric methods, Cl- – using a chloride-selective electrode pH-meter. The chemical composition of cervical enamel of 29 removed intact teeth and with cervical pathology was studied using a scanning electron microscope JSM-6490 LV with energy-dispersive X-ray microanalysis system INCA Penta FETx3. Molar coefficients were calculated as the ratio of the number of chemical analytes in the supernatant. Statistical analysis was performed using the computer program Statistica 8.0 (STA862D175437Q). Applied: analysis of variance (Welch test), correlation analysis (Pearson's parametric correlation method) based on the determination of the parametric Brave-Pearson coefficient (r) at p<95%. The reliability of the obtained results was evaluated by Student's t-test and by Student's test using the Z-test (Fisher's z-test) at p≤0.05. There was no significant difference in the amount of chemical elements in saliva between the groups (p>0.05) and significant differences were determined in K/Na (p=0.0258). There was correlation between chemical analyte content in the oral fluid and cervical tooth enamel: direct ‑ between Са2+ and РО43-, К+ and Cl-, К+ and Na+; inverse – between Са2+ and К+, Са2+ and Cl-, РО43- and К+, РО43- and Cl- (p<0.0001). Correlation was identified: direct – between Ca/P and Ca/Mg, Ca/P and Ca/Cl, P/Ca and K/Na, Mg/Ca and Mg/P; inverse -‑between K/Na and Ca/P, K/Na and Ca/Cl, P/Ca and Ca/Cl, P/Ca and Ca/P (p≤0.05). Obtained results allowed to use Ca/Mg ratio as an indicator of enamel mineralization. We propose to use certain differences in correlation of chemical elements of oral fluid and tooth enamel to assess the mineral state of tooth enamel and control the effectiveness of preventive measures. Based on saliva parameters and microbiological indicators of dental biofilm the search for ways of preclinical diagnosis of cervical pathology is promising.

Anion-Responsive Manganese Porphyrin Facilitates Chloride Transport and Induces Immunogenic Cell Death

Anion-Responsive Manganese Porphyrin Facilitates Chloride Transport and Induces Immunogenic Cell Death

Method for predicting the development of cervical caries and teeth with wedge-shaped defect in young people

Annotation. Significant prevalence of cervical caries and teeth with wedge-shaped defect is the reason for the search for ways to predict their development that is possible only with an individual approach. The purpose of the study is to design and test the method for predicting the development of cervical caries and teeth with wedge-shaped defect in young people based on the results of determining the chemical composition of enamel, dentin and oral fluid. The chemical composition of the enamel and dentin of 29 teeth was examined using JSM-6490 LV focused beam electron microscope (scanning). We determined the content of the chemical elements in the oral fluid of 33 patients: Сa2+, РО43-, SO42 - by spectrophotometric method, Na+, К+, Al3+ by atomic emission spectrometry, Mg2+, Zn2+ by atomic absorption spectrometry, Cl- using chloride selective electrode of pH meter. Statistical analysis was performed using the computer program Statistica 8.0 (STA862D175437Q). Analysis of variance (Welch test), Pearson's parametric correlation method (Brave-Pearson coefficient (r)) was used. The reliability of the obtained results was evaluated by Student's t-test, the correlation between the indicators – by Student's test using the Z-test (Fisher's z-test) at p≤0.05. It was determined that the values of the К/Na+Са/Сl coefficient in enamel (equator, cervical region), dentin (cervical region), oral fluid significantly differed depending on the state of hard dental tissues (p≤0.05). Direct correlation of moderate and high strength was revealed between Са/Р and К/Na+Са/Сl – coefficients in cervical enamel and saliva (p≤0.0001). Obtained results became the basis for the development of the method for individual prediction of the development of cervical pathology in young people. Its approbation was carried out in 43 patients, its effectiveness was assessed a year later. With the values of the К/Na+Са/Сl 2 coefficient and lower we diagnosed the absence of the risk of developing cervical caries and wedge-shaped defect, from 2.1 to 5.3 the risk of developing cervical caries was diagnosed, from 5.4 and more the risk of developing wedge-shaped defect was found out. It was confirmed that the proposed method is informative (the prediction accuracy reaches 83,7%), its non-invasiveness is the basis for widespread use. We consider the search for the ways to predict particularly the development of teeth cervical pathology based on the parameters of the oral fluid and dental biofilm to be promising.

Solute–Solute and Solute–Solvent Interactions in the Ternary LiCl + Sucrose + Water System at 298.15 K

In this work, the potentiometric method was used to study the thermodynamic properties of the ternary LiCl + sucrose + water system, where the galvanic cell contained a solid-state chloride-selective electrode and a sodium-selective glass electrode. Measurements have been made for LiCl electrolyte concentrations ranging from 0.0046 up to about 3.800 mol·kg−1 in aqueous sucrose solutions whose molalities varied between mN = 0.1537 and mN = 5.4255 molal (65 wt%). Activity coefficients and standard Gibbs energies of transference of the electrolyte have been determined at 298.15 K. For describing the variation of activity coefficients of LiCl, Pitzer’s equation and a modified form of Pitzer’s equation were used and it was shown that there is a good agreement between them. Evaluation of activity coefficients and the optimized parameters of the two models made it possible to discuss the non-ideality behaviors of the systems in terms of solute–solute and solute–solvent interactions and of their variation according to medium effects. The interactions between electrolyte, sucrose and water were also interpreted in terms of the Gibbs energies of pairwise interaction gEN, for which the positive sign implies repulsive forces between the electrolyte and sucrose. Moreover, the estimated value of the primary hydration number of lithium chloride was within the range of those found by other researchers. Finally the calculated salting constant has confirmed that sucrose may be salted-out by the electrolyte and this fact is consistent with the literature.

Effect of different organized media on ion-selective electrode (ISE) determination of propranolol in pharmaceutical dosage forms

This study examined the effect of different organized media such as β-cyclodextrin and micelle surfactants, either anionic (sodium dodecyl sulphate), cationic (cetrimide) or non-ionic (tween-20 and tween-80), on the potentiometric properties of propranolol polyvinyl chloride selective electrode based on tetraphenyl borate (PRO-TPB) ion-exchanger as an electroactive material. It was found that the Nernstian slope for propranolol over the concentration range of 1 × 10-5 to 10-2 M was unaffected by non ionic surfactant, whereas cationic surfactant significantly decreased the Nernstian slope. However, anionic surfactant significantly increased the Nernstian slope. The electrode basic analytical parameters such as measurement range, slope characteristics, detection limit, response time, and selectivity coefficients in relation to some inorganic cations, sugars, amino acids and some β-blockers were investigated in presence or absence of organized media. Electrode was used for the potentiometric determination of propranolol in pharmaceutical preparations with and without organised compounds. The results were consistent with those obtained using a reference method.

New Poly Vinyl Chloride Ion Selective Electrode for Potentiometric Analysis of Propranolol in its Pharmaceutical Formulations and Human Fluids

New, simple, sensitive and rapid method for the determination of propranolol in the pharmaceutical preparations and human fluids. The Buildup and electrochemical response characteristics of a poly vinyl chloride (PVC) selective membrane electrode for the determination of propranolol (POP) are described in this research. The proposed electrodes was composed of propranolol-bromophenol blue as ion-exchanger and Di-butyl phthalate (DBPH) (electrode A), tris (2-ethylhexyl) phosphate (TEHP) (electrode B), and ortho-nitrophenyloctylether (ONPOE) (electrode C), as plasticizers. The slope was 50.94, 57.77, and 49.75 mV/decade for electrode A, B and C. the linear range was 5 ×10-5 – 1×10-2, 1×10-4 – 1×10-2, and 5×10-5 – 1×10-2 M, a detection limit of 4.2×10-5, 8.9×10-5, and 4.8×10-5 M, lifetime of 21, 42, and 1-day, respectively. Electrode B gives the best results, so the application of pharmaceutical and human fluids was based upon this electrode, the recovery percentage was 103, 101, 102.5, and 104 for POP tablet 10mg, tablet 40mg, urine and plasma by standard addition method, respectively.

Application of Ag/AgCl Sensor for Chloride Monitoring of Mortar under Dry-Wet Cycles.

An Ag/AgCl electrode used as a corrosion sensor in a reinforced concrete structure is considered as having good application prospect. However, its performance under complex conditions, such as dry-wet cycle condition, is not affirmed. In the current study, the performance of Ag/AgCl as chloride selective electrode in mortar exposed to dry-wet cycle condition was investigated. A simple Ag/AgCl electrode was prepared and fabricated by electrochemical anodization. These Ag/AgCl electrodes were embedded into a mortar specimen with temperature sensors, humidity sensors and anode ladder monitoring system (ALS). After 28 d curing time, the upper surface of mortar specimen was wetted (with 5% NaCl solution) and dried regularly. The obtained results indicate that Ag/AgCl electrode responds to the ingress of chloride ion, sensitively. The chloride ion concentration variation can be reflected by the potential trend. Furthermore, the balance potential of Ag/AgCl electrodes is influenced by dry-wet cycles. Compared with ALS, it demonstrates that Ag/AgCl electrodes are more sensitive to chloride. The research provides the key element for the specific application of Ag/AgCl electrode for corrosion monitoring in the future.

Simple isophthalamides/dipicolineamides as active transmembrane anion transporters

ABSTRACTEight N,N´-diarylisophthalamide/dipicolineamide derivatives have been synthesised and fully characterised, both in solution and in the solid state. The transmembrane anion transport properties of these compounds have been studied by chloride-selective electrode and fluorescence experiments. The substitution pattern of the aromatic moieties determines the transport properties of these systems, with those containing electron-withdrawing groups in their structures being the most active ones of the series.

Molecular organic materials intermediate layers modified with carbon black in potentiometric sensors for chloride determination

Design of sensors with improved parameters is still an extensive field of analytical research. A comparative study between seven types of all-solid-state ion-selective electrodes (ASS-ISEs) and coated disc ion-selective electrode (CD-ISE) was carried out. This work developed solid contact layers designed from molecular organic materials (MOMs): tetrathiafulvalene (TTF), its chloride salt (TTFCl) or tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) with or without the addition of carbon black (CB) acting as inner transducers. Intermediate layers were deposited by a solution casting on the top of glassy carbon disc electrodes and then were covered with a membrane containing tridodecylmethylammonium chloride, o-nitrophenyl octyl ether, and poly(vinyl chloride). Molecular organic conductive materials were compared with CB-MOM composites as materials responsible for transduction process in all-solid-state chloride-selective electrodes. The proposed solid contact layers were characterized by scanning electron microscopy and electrochemical methods. The intermediate layer effect on the electrodes was tested, and prepared sensors were investigated by potentiometric, chronopotentiometric and electrochemical impedance spectroscopy measurements. All the modified electrodes displayed a satisfactory performance and Nernstian electrode function for chloride in the concentration range from 10−5 M to 10−1 M, however the best sensitivity and detection limit were observed for the CB-TTFCl-contacted electrode. The obtained results showed that the electrodes with internal layer consisting of CB-MOM nanocomposite presented slightly more sensitive response to chloride, lower impedance and a higher capacitance than electrodes based only on various molecular organic materials.

A Method of Preparation of Ag/AgCl Chloride Selective Electrode

We put forward a method of rapid preparation of chloride selective electrode (Ag/AgCl electrode) by dipping silver wire into sodium hypochlorite solution. The electrodes were prepared through different immersion time. The properties of the electrodes, such as Nernst response, response time and long-term stability, were tested in simulated concrete pore solutions (SCPS). Moreover, the surface morphology of the electrodes was also detected after immersion in solutions over three months. The experimental results reveal that the Ag/AgCl electrode with the fabrication time of 20 minutes (E-20) which is recommended to work as the chloride ion selective electrode has the best performance. Compared to that fabricated by the electrolytic process (E-EP), E-20 can be manufactured in mass. The method has almost the same good performance of Nernst response as E-EP, and has a better response time which is less than 25 seconds. The method also shows a better good long-term stability in SCPS containing chloride ions over three months.

Determining the chlorine content in the blast-furnace system

The production of ferrous metals and the extraction and processing of raw materials are environmentally hazardous. Besides atmospheric and water pollution, many solid wastes are formed. Chlorine plays a special role in blast-furnace processes. The chlorine compounds present in the blast-furnace gas lead to the corrosion of pipelines, air heaters, and tuyeres in the furnace. The behavior of chlorine in the blast furnace determines the sinter properties during the reduction process. If the content of mineral chlorine (chlorine bound with metals) in residues at filters and dust traps is monitored, the toxicity of the wastes may be assessed, and the production processes may be evaluated. The chlorine content is determined by various physical methods: atomic-emission spectrometry, mass spectrometry with inductively bound plasma, and neutron-activated analysis. However, chemical methods have been widely adopted: titrimetric, photometric, electrochemical, and ion-chromatographic methods. It is important to develop fast and inexpensive methods of determining chlorine for the analysis of materials encountered in technological systems, including metallurgical systems. In the present work, attention focuses on samples of blast-furnace slag from PAO Tulachermet and dusty wastes from PAO Kosogorskii Metallurgicheskii Zavod. X-ray fluorescent methods are used for preliminary analysis of the sample composition. The interfering influence of other components is considered. Ionometric determination of chlorine by means of a crystalline chloride-selective electrode is proposed. The samples are decomposed by high-temperature sintering in a mixture with Na2CO3 and ZnO and subsequent leaching with water. The details of this method are described. The results of the analysis are confirmed by variation in the sample weight (n = 10; t tab = 2.26, P = 0.95) and also by comparison with X-ray fluorescent data. The precision of ionometric determination of chlorine in the blast-furnace system is assessed. The working range of the chlorine concentrations observed is 0.037–1.340 wt %.

A semiconductor sensor based on indium antimonide for the potentiometric analysis of soils from the Chinarev oil and gas field

The ion−salt composition of soils from the Chinarev oil and gas field (West Kazakhstan Region) was studied. A semiconductor sensor based on indium antimonide (InSb) and classical ion-selective electrodes were used to analyze soil extracts. Comparative results of determinations of pH, HCO3- Cl–, and SO42- in soil samples with a semiconductor InSb-electrode and with glass, chloride-selective, and copper-selective electrodes are presented. The use of a single semiconductor sensor for the determination of four components in a soil extract allowed us to reduce the duration of analysis and to unify the determination. Based on the results obtained, the salt composition of soils from the studied field was estimated.

Investigation on the performance characteristics of chloride selective electrode in concrete

A monitoring technique based on the chloride selective electrodes for the chloride content in concrete which is accurate, non-destructive, and continuous would be highly desirable. For this reason, the performance, such as Nernst response and resisting polarization, of the electrode was tested both in simulated concrete pore solutions and concrete. Moreover, the surface morphology of electrode after immersion in solutions over 3 months was detected. Results revealed that the electrode potential showed a good Nernst response with chloride concentration and was affected little by sulfate ion. The detection limit for the chloride concentration was 10−3 mol L−1 at pH 13.5 and 10−4 at lower pH values. In addition, the electrode also had a high exchange current density and a high equivalent capacitance. The Ag/AgCl coating showed good long-term stability over 3 months in solutions containing chloride ions. Besides, there was a good agreement between the free chloride content determined by the electrode and by pore solution expression.

Flexible Chloride Sensor for Sweat Analysis

This work demonstrates a low cost flexible sweat patch, which consists of a reference electrode and an array of chloride selective electrodes for real-time monitoring chloride concentration in sweat. The chloride sensitive electrodes were made by screen printing AgCl paste on polyethylene terephthalate (PET) substrate. The AgCl electrodes were stable for more than a week in liquid and showed a chloride sensitivity of 57mV per decade. A reference electrode (RE) was successful developed on the same patch by adding a polyhydroxyethylmethacrylate hydrogel layer on top of one of the AgCl electrode in the array and followed by conditioning in 3M KCl solution. The sweat patch, which was worn on the chest of a test subject during an one hour treadmill exercise, was able to continuously detect the chloride ions in a small amount of sweat adsorbed in a gauze layer placed on top of the patch.

Chloride-selective electrodes based on "two-wall" aryl-extended calix[4]pyrroles: combining hydrogen bonds and anion-π interactions to achieve optimum performance.

The performance of chloride-selective electrodes based on "two-wall" aryl-extended calix[4]pyrroles and multiwall carbon nanotubes is presented. The calix[4]pyrrole receptors bear two phenyl groups at opposite meso-positions. When the meso-phenyl groups are decorated with strong electron-withdrawing substituents, attractive anion-π interactions may exist between the receptor's aromatic walls and the sandwiched anion. These anion-π interactions are shown to significantly affect the selectivity of the electrodes. Calix[4]pyrrole, bearing a p-nitro withdrawing group on each of the meso-phenyl rings, afforded sensors that display anti-Hofmeister behavior against the lipophilic salicylate and nitrate anions. Based on the experimental data, a series of principles that help in predicting the suitability of synthetic receptors for use as anion-specific ionophores is discussed. Finally, the sensors deliver excellent results in the direct detection of chloride in bodily fluids.

Speciation of [ZrCl<sub>x</sub>(OH).y(H<sub>2</sub>O)<sub>z</sub>]<sub>q</sub> by electrochemical measurements

Speciation of [ZrClx(OH).y(H2O)z]q by electrochemical measurements. Speciation of zirconium complexes is important for liquid-liquid extraction of the metal. Spectrophotometry cannot be used as speciation method because d0-complexes form in an aqueous solution, and therefore the use of a chloride selective electrode is tested by firstly applying it to iron(III) chloride speciation, which is known.

Evaluating capacitive deionization for water desalination by direct determination of chloride ions

Ionic conductivity and capacitance measurements are widely used methods for evaluating the desalination efficiency in capacity deionization processes. In this study, these methods are revised and several problems associated to them are identified and evaluated. Furthermore, a new method based on the determination of the chloride ion concentration by means of a chloride selective electrode is proposed as a more reliable alternative for evaluating the desalination performance in these systems. This method has been shown not only to be precise in a wide range of salt concentrations but also to be independent of pH, one of the main limitations of the determinations based on ionic conductivity measurements.

BEHAVIOR OF A POLYMERIC LIQUID MEMBRANE ION- SELECTIVE ELECTRODE FOR CHLORIDE ION

Chloride selective polymeric liquid membrane electrode has been developed by using Bis-(2-ethylhexyl) Sebacate (DOS) as plasticizer and 2-[5-(4-nitrophenyl) furyl]-4,5-diphenyl imidazole (FFDFIN) as ionophore. Some parameters of evaluation of the electrode are presented in this work. The constructed electrode showed fast potentiometric response to chloride ion in the concentration range from 10-6 to 10-2 mol.dm-3 with Nernstian slope of -63.43 ± 0.85 mV/decade, response time of 25 seconds and life time of 15 days.

Selectivity Enhancement for Chloride Ion by In(III)‐Porphyrin‐Based Polymeric Membrane Electrode Operated in Pulsed Chronopotentiometric Mode

A robust selectivity enhancement of an In(III)-porphyrin ionophore-based chloride-selective electrode under pulsed chronopotentiometric measurement mode that enables the detection of chloride ions in the presence of a normally interfering concentration of salicylate ions is described. This enhancement is achieved by the rapid depletion of the surface concentration of the more dilute lipophilic anion during an initial anodic current pulse period due to extraction of this preferred anion into the membrane phase. Measurement of chloride with a detection limit of 8 mM and near Nernstian response slope in the presence of 1 mM salicylate is possible using the pulstrode method.