Showing papers on "Polarography published in 2022"
TL;DR: In this article , the authors highlight some of the most important achievements of voltammetry so far and highlight the role of nanomaterials in the development of the field of electrochemical microscopy.
Abstract: It is exactly one hundred years ago when the first paper about the development of polarography was published in 1922. Polarography is considered a predecessor of voltammetry, and this iconic electrochemical technique was designed by the Nobel laureate Jaroslav Heyrovsky. In this short review, the aim is to highlight some of the most important achievements of voltammetry so far. While hints are given to some of the most important theoretical works related to various electrode mechanisms in cyclic voltammetry and pulse voltammetric techniques, a critical part is written that should help to improve the communication between theoretical and experimental electrochemists. Since a main application of voltammetry is in the field of constructing biosensors, some of the major achievements and several drawbacks of applying voltammetric techniques in designing sensors are discussed. In a small part of this review, the role of nanomaterials in voltammetry is also considered. As scanning electrochemical microscopy (SECM) seems to be most promising instrumental system that will bring voltammetry a step closer to probing real biological systems, critical aspects about the weaknesses of this technique are also briefly discussed. In the final outlooks, we present a set of directions in which voltammetry will develop in the coming years. The paper is written in a way to motivate younger electrochemists to get more involved in exploring the voltammetry.
2 citations
TL;DR: In this article , the authors reduced quinones in aqueous/organic mixtures with dielectric constants (ε) from 78.4 to 47, using protic or aprotic organic co-solvents.
Abstract:
We reduced quinones in aqueous/organic mixtures with dielectric constants (ε) from 78.4 to 47, using protic or aprotic organic co-solvents. The increase in half-wave potential (E1/2) with declining ε was fit to the Born equation down to ε ≈ 55. Cu2+ and ubiquinone-0 were reduced in a two-electron step that was more ε-sensitive with aprotic co-solvent. Naphtho- and anthraquinone were reduced in two one-electron steps that were influenced identically by protic or aprotic co-solvents. The first reduction wave produced neutral semiquinone (·QH), which was protonated to ·QH2
+ before reduction in the second wave. Most radii derived from fitting E1/2 vs. ε data to the Born equation were too small; non-electrostatic effects destabilized the oxidized species, enhancing the Born electrostatic increase in E1/2. Additionally, for ε < 55, deviation from the Born equation was probably due to changes in solvent structure, dynamics, and solvent-solute interactions. Finally, quinones were incorporated into phosphatidyl choline sonicated vesicles: Ubiquinone-0 had two irreversible two-electron reduction waves, one from a membrane surface-bound population, and another (whose E1/2 was negatively shifted by 150 mV) localized in the membrane interior. Ubiquinone-10 had a single irreversible two-electron reduction wave that was 250 mV more negative than the UQ-0 membrane-interior population.
1 citations
1 citations
TL;DR: In this article , a Clark-type polarographic oxygen electrode device (OXYG1-PLUS) was introduced for oxygen measurement, allowing the dilution of fine bubbles without the influence of ambient air and the adhesion of FBs on the electrode surface due to its special shape.
Abstract: Fine bubbles (FBs) have attracted significant attention in several research fields. Although some reports have argued that FB dispersion is useful as an oxygen (gas) carrier, only a few reports have examined its properties as an oxygen carrier using experimental data. As one of the reasons for this, there are no standard methods for measuring the oxygen content in FB dispersions. Conventional oxygen measurement methods have certain drawbacks in accuracy or speed; thus, it is difficult to use oxygen content as the primary outcome. In this study, we introduce a Clark-type polarographic oxygen electrode device (OXYG1-PLUS) for oxygen measurement, allowing the dilution of FB dispersion without the influence of ambient air and the adhesion of FBs on the electrode surface due to its special shape. First, the accuracy of our dilution method was evaluated using pure water as a sample, and it was confirmed that our method could measure with an accuracy of ±0.5 mg/L from the results with conventional dissolved oxygen meters. Second, the oxygen content in FB dispersion was evaluated with our method and a chemical titration method (Winkler’s method), and it was found that our method could measure the oxygen content in FB dispersions quantitively. This method satisfies the easiness (4 steps) and quickness (within 8 min) for a wide range of oxygen contents (0 to 332 mg/L, theoretical range) with low coefficient variation (< 4.7%) and requires a small sample volume (50–500 μL); thus, it is a useful method for measuring the oxygen in FB dispersions.
1 citations
1 citations
TL;DR: In this article , a review of non-mercury configurations that have been reported in the literature as the working electrodes applicable in polarographic measurements is presented, discussed, and critically assessed with respect to their potential employment in the present day's electrochemistry and electroanalysis.
Abstract: This article reviews non-mercury configurations that have hitherto been reported in the literature as the working electrodes applicable in polarographic measurements. The individual types, namely gallium, liquid amalgams, dropping electrolyte, and carbon fluid electrodes, together with a carbon paste-based assembly or even solid disc electrodes with a periodically renewable surface, are presented, discussed, and critically assessed with respect to their potential employment in the present day's electrochemistry and electroanalysis.
1 citations
TL;DR: In this article , the United States Environmental Protection Agency (U.S.EPA) has put forth SW-846, Method 7198, using differential pulse polarography for determination of hexavalent chromium in both, the natural as well as waste waters.
Abstract: The accurate determination of hexavalent chromium in environmental matrices such as natural and waste waters is crucial for the safety of both human and wildlife populations. The United States Environmental Protection Agency (U.S.EPA) has put forth SW-846, Method 7198, using differential pulse polarography for determination of Cr (VI) in both, the natural as well as waste waters. In Method 7198, the cathodic peak current resulting from the reduction of Cr (VI) to Cr (III) is measured and the concentration range for this method is listed as 10 ppb to 5 ppm Cr (VI). Using BASi Epsilon potentiostat that is specifically made for measuring ultra-low current resolutions and a controlled growth mercury electrode (CGME) set-up, the US EPA method 7198 has been successfully optimized in this work for higher detection limits. It is observed that a detection limit of up to 7 ppb can be easily obtained by efficiently managing the interference of iron and sulphur through a combination of various supporting electrolytes. This work may also become a valuable source of reference information on the behavior of wide variety of electrolytes and their control parameters needed to achieve extremely low detection limits.
Figure 1
13 Jun 2022
TL;DR: In this paper , the electrochemical properties of inorganic and organothallium compounds were investigated using differential pulse polarization (DPP) and differential pulse anodic stripping voltammetry (DPASV).
Abstract: Because of increasing concern over global pollution by the energy production industry, especially large, centralized utility complexes, the quantitation and speciation of heavy metals have taken on great importance. These metals are emitted with coal fly ash and may be subsequently deposited in natural waters. Complications arise when certain inorganic compounds undergo biomethylation by microbial action in these waters. Therefore, procedures must be developed to analyze and differentiate the mixture of inorganic and organometallic compounds present. This work is a study of the electrochemical properties of inorganic and organothallium compounds. The toxicological significance of thallium compounds is known, and their presence in coal fly ash and natural waters indicates a need for study of their mixtures. Environmental concentrations are thought to be in the ppb range so that very sensitive quantitation procedures must be developed. After discussions of the current literature and the theory pertinent to this work are presented, the experimental procedures for electrochemical analyses are described. Cyclic voltammetry experiments allowed the determination of the irreversible nature of the electron transfer reactions of organothallium compounds used, (CH(,3))(,2)TlI and (CH(,3))(,2)TlNO(,3), and described the transfer coefficients and rate constants for them. The similarity of these respective coefficients as well as the diffusion coefficients found by normal pulse polarography confirmed their ionic nature, appearing as (CH(,3))(,2)Tl('+), in aqueous solutions. Also, its was shown that they undergo a three-electron reduction to Tl(DEGREES). Routine analytical methods were developed for mixtures of TlNO(,3) with (CN(,3))(,2)TlI and (CH(,3))(,2)TlNO(,3) using differential pulse polarography (DPP) and differential pulse anodic stripping voltammetry (DPASV). Direct speciation and quantitation of these solutions were accomplished with DPP at the ppm level. DPASV allows the same analyses at the ppb level by making use of the different electrolysis potentials of the compounds. This method is applicable to other metal systems and is adaptable to field analyses.
TL;DR: Differential Pulse Polarography (DPP) was used in this article to determine Cd and Pb levels in cold-pressed olive oil brought from 5 different provinces of Turkey, where the samples were dissolved in microwave digestion using concentrated HNO3 and H2O2, and analyses were carried out in acetate buffer (pH 4) to which EDTA was added.
Abstract: In this study, Differential Pulse Polarography (DPP) method was preferred of Cd (II) and Pb (II) levels, which have toxic effects. This method was applied to determine Cd and Pb levels in cold-pressed olive oil brought from 5 different provinces of Turkey. The samples were dissolved in microwave digestion using concentrated HNO3 and H2O2. Analyses were carried out in acetate buffer (pH 4) to which EDTA was added. The LOD for Cd and Pb was found as 0.74, 0.52 µg L-1 and the LOQ was 0.96, 0.82 µg L-1. Additions were made from standard Cd and Pb solutions and the % recovery values were measured as 98 and 99. The relative standard deviation (RSD, %) was found < 5. This method was found to be sensitive to the analyses of two toxic elements in cold pressed olive oil.
TL;DR: In this paper , the curcumin reaction in blood was studied by cyclic voltammetry (CV) using a glassy carbon electrode (GCE) to find each of the electrochemical parameters such as different concentrations, pH, scan rates, and reliability.
Abstract: Curcumin is a chemical produced from the Curcuma longa family. Curcumin compounds can be used in various types of cancers. The study focused on the electrochemical properties of curcumin in the blood medium. The redox reaction of curcumin in blood was studied by cyclic voltammetry (CV) using a glassy carbon electrode (GCE) to find each of the electrochemical parameters such as different concentrations, pH, scan rates, and reliability (stability). In-vitro experiments found that the activity of curcumin in the blood has good behavior against disease through the interaction of curcumin molecules with blood components that have only one peak reduction current that appeared at a voltage of -0.750 V. A good indication for these reactions is to serve as an antioxidant reagent enhanced by the alkaline medium (pH = 8) of the blood medium. Also, the curcumin compounds present in the alkaline medium can be used for patients suffering from cancer diseases.
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TL;DR: The cover image is part of the special collection celebrating 100 Years of Polarography, edited by Jiří Ludvík and Alan Liŝka, from the J. Heyrovský Institute of Physical Chemistry, Prague as mentioned in this paper .
Abstract: Electrochemical Science AdvancesVolume 2, Issue 6 e2280601 Cover pictureOpen Access Cover Picture First published: 21 December 2022 https://doi.org/10.1002/elsa.202280601AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Graphical Abstract The cover image is part of the special collection celebrating 100 Years of Polarography, edited by Jiří Ludvík and Alan Liŝka, from the J. Heyrovský Institute of Physical Chemistry, Prague. Read the Editorial: https://doi.org/10.1002/elsa.202260007. Volume2, Issue6December 2022e2280601 This article also appears in:100 Years of Polarography RelatedInformation
21 Apr 2022
TL;DR: In this paper , a tentative structure has been suggested to the Zn(II) -Aspirin complex and its physicochemical and microbial studies have been carried out in solid and aqueous phases.
Abstract: Stroke is becoming one of the biggest health hazardous now days. According to the data, it is estimated that it is becoming a third leading cause of death throughout the world. Aspirin, acetil salicylic acid is well known analgesic, anti-inflammatory and antipyretic drug. It also is having anticancer, anti-oxidant and anticonvulsant property. It plays a significant role in reduction of blood clotting as well as anti-stroke drug. But Aspirin has a property to cause ulcer and Zn bio metal is known to possess anti-ulcer as well as anti-inflammatory property. Keeping the importance of Zn(II) bio metal in mind and Zn(II) - Aspirin complex is prepared, its physicochemical and microbial studies have been carried out in solid and aqueous phases. On the basis of polarographic studies amperometric titrations and IR spectral studies the probable formula for the complex has been worked out to be 1:2. The metal ligand interaction has been studied using polarographic method at 27ºC and ionic strength µ = 1.0. A tentative structure has been suggested to the complex. A microbial study on the complex was carried out against various pathogenic bacteria and fungi. The results of studies revealed that the complex is more effective anti-stroke drug as compared to pure Aspirin.
TL;DR: In this article , a short-time asymptotic analysis is performed to establish corrections of the Ilkovich equation, which describes the polarographic response of a dropping mercury electrode.
Abstract: A short-time asymptotic analysis is performed to establish corrections of the Ilkovich equation, which describes the polarographic response of a dropping mercury electrode. The convective diffusion equation governing diffusion limited reactant flux for small drop times is solved by a regular perturbation based on powers of the sixth root of time. This produces a framework within which higher terms of the Ilkovich equation can be derived systematically. As well as reproducing Ilkovich’s original formula and verifying Newman’s correction of Koutecky’s first-order term, we calculate the second-order term for the first time. The calculation is compared to the Newman–Levich procedure and tested against numerical simulations with finite-element software.
08 Dec 2022
TL;DR: In this article , the levels of lead and cadmium in the liver samples of slaughtered sheep in Zanjan and Sanandaj were investigated in the summer of 2014, and 96 samples were collected from both cities.
Abstract: Background: Lead and cadmium can enter the human body through consuming the liver of animals such as sheep, which may accumulate and cause adverse effects. The levels of lead and cadmium in the liver samples of slaughtered sheep in Zanjan and Sanandaj were investigated in the summer of 2014. Methods: 96 Samples were collected from both cities. Lead and cadmium levels were measured by anodic stripping voltammetry (ASV) after digestion with nitric acid and hydrogen peroxide in 3 steps by a 400-watt microwave digester. Lead and cadmium concentrations were determined in µg/L using standard solutions of lead and cadmium as standard addition in their specific potential, -0.42 and -0.58 V for lead and cadmium, respectively. Results: Mean values of cadmium in the livers of sheep in Zanjan and Sanandaj were 0.42 ± 0.13 and 0.35 ± 0.13 mg/kg, respectively, which had no significant difference (P < 0.05). On the other hand, mean concentrations of lead in the livers of sheep in Zanjan and Sanandaj sheep were equal to 3.69 ± 1.43 and 2.36 ± 0.18 mg/kg, respectively, which had a significant difference (P < 0.05). Conclusion: The concentrations of lead and cadmium in the livers of sheep were higher than WHO standards. However, only the lead levels were higher than the maximum residue levels (MRLs) standard lists. The obtained results can be due to the activities of lead industries and factories in both cities, which may increase pollution levels in the water, air, and animal feed.
14 Jun 2022
TL;DR: In this article , the United States Environmental Protection Agency (U.S.EPA) has put forth SW-846, Method 7198, using differential pulse polarography for determination of hexavalent chromium in both, the natural as well as waste waters.
Abstract: The accurate determination of hexavalent chromium in environmental matrices such as natural and waste waters is crucial for the safety of both human and wildlife populations. The United States Environmental Protection Agency (U.S.EPA) has put forth SW-846, Method 7198, using differential pulse polarography for determination of Cr (VI) in both, the natural as well as waste waters. In Method 7198, the cathodic peak current resulting from the reduction of Cr (VI) to Cr (III) is measured and the concentration range for this method is listed as 10 ppb to 5 ppm Cr (VI). Using BASi Epsilon Potentiostat that is specifically made for measuring ultra-low current resolutions and a controlled growth mercury electrode (CGME) set-up, the US EPA method 7198 has been successfully optimized in this work for higher detection limits. It is observed that a detection limit of up to 7 ppb can be easily obtained by efficiently managing the interference of iron and Sulphur through a combination of various supporting electrolytes. This work may also become a valuable source of reference information on the behavior of wide variety of electrolytes and their control parameters needed to achieve extremely low detection limits.
Figure 1
TL;DR: Primary teeth are an important biological indicator to evaluate the concentration of heavy elements in the human body and could be attributed to the high concentrations of these Elements in the environment of Zanjan.
TL;DR: In this paper , a short overview of the major achievements of five women electrochemists who contributed immensely to the theoretical and practical application of pulse voltammetric technique is presented.
Abstract:
It is exactly a century since polarography was developed, which is seen as a predecessor of all voltammetric techniques. As cyclic voltammetry (CV) is the most prominent member in the family of voltammetric techniques for mechanistic studies, the socalled “pulse voltammetric techniques” emerged as simple and viable alternatives to CV for mechanistic characterizations and analytical application, as well as for kinetic and thermodynamic evaluations. The theories and practical application of pulse voltammetric techniques were largely developed by several women electrochemists. In this short overview, we outline some of the major achievements of five women electrochemists who contributed immensely to the theoretical and practical application of pulse voltammetric technique. Since the theory and application of pulse voltammetric techniques largely relies on the works of Janet Osteryoung, Sebojka Komorsky Lovric, Angela Molina, Anna Brainina, and Oliveira Brett, we give in this review a short historical overview of the major accomplishments of these five exceptional women electrochemists
TL;DR: In this article , the results of a series of investigations on the indirect chronovoltametric dosing of alkaline earth metals, carried out in the Laboratory of the Analytical Chemistry at the Institute of Chemistry, currently called the laboratory of Physicochemical Methods of Research and Analysis, conducted in 1971-1993 by the doctor of chemical sciences Ion Vatamanu, are presented.
Abstract: The paper presents the results of a series of investigations on the indirect chronovoltametric dosing of alkaline earth metals, carried out in the Laboratory of the Analytical Chemistry at the Institute of Chemistry, currently called the Laboratory of Physicochemical Methods of Research and Analysis, conducted in 1971–1993 by the doctor of chemical sciences Ion Vatamanu. During the elaboration of the presented polarographic methods for determining the ions of alkaline-earth metals, a series of techniques were used to increase the sensitivity and selectivity of the determination. Based on two indirect polarographic methods for measuring alkaline earth metals, developed by Ion Vatamanu and coworkers and analyzed in this paper, two fundamental physicochemical principles were applied: (I) anion-induced adsorption of ligands adsorbed on the electrode surface and (II) thermodynamic determination of the optimal dosing conditions by calculating the conditional constants or the equilibrium chemical composition of complex reactant systems. The developed methods were used in the electrochemical analysis of standard alloy samples based on various metals, in the analysis of semiconductor systems, ferrous metals, nickel electrolytes, copper plating, cadmium plating, chromium plating, aluminum oxidation, wastewater analysis in galvanic baths, clays and limestones from Moldovan deposits, determination of pesticides, tanning extracts, dyes for the textile industry, etc.
TL;DR: In this article , the Differential Puls Polarographic Techanique was used to determine the kinetics parameters (Kס f,h , αn) using Meites- Israel method, also thermodynamic parameters such as enthalpy change (∆H), free energy chang ( ∆G) , entropy change(∆S) of poly hydroxylated flavonoids, the quercetin molecule, at (293- 313k).
Abstract: Dietry flavonoids(Poly phenols) are important phytonutrient component widely distributed in plant foods , flavonoids have beneficial biological activities,such as antioxidant activity , flavonoids can chelate with metal ions , the interaction of lead(׀׀) ion with a poly hydroxylated flavonoids, the quercetin molecule,were investigated electrochemically in acidic media .The Differential Puls Polarographic Techanique was used to determine the kinetics parameters (Kס f,h , αn) using Meites- Israel method, also thermodynamic parameters such as enthalpy change (∆H), free energy chang (∆G) , entropy change(∆S) of Pb+2 – complexes with Quercetin at (293- 313k) . The(Kסf,h, αn)values for the kinetics of the electrode processes show that the electrode processes were irreversible and diffusion controlled.
TL;DR: Polarography was used to determine the stability constants (log b) of mixed ligand bioinorganic complexes of Mn (II) with some antibiotics as primary ligands and aspirin as secondary ligand at pH=7.30 ± 0.01 and ionic strength m=1.0 M NaClO4 at 298 K as mentioned in this paper .
Abstract: Polarography was used to determine the stability constants (log b) of mixed ligand bioinorganic complexes of Mn (II) with some antibiotics as primary ligands and aspirin as secondary ligand at pH=7.30 ± 0.01 and ionic strength m=1.0 M NaClO4 at 298 K. The waves of Mn and its complexes were quasireversible. Mn (II) formed 1:1:1, 1:2:1 and 1:1:2 complexes. Stability of these complexes is explain on the basis of sizes and basic nature of these Ligands.
TL;DR: In this paper , a new Zn(II)-salicylidene-4-p-chlorophenyl)-2-aminothiazole (SCAT) ligand was synthesized and studied in DMF media by the polarographic method and produce a DC and DPP polarogram in KCl (supporting electrolyte) with Britton- Robinson buffer.
Abstract: Newly Zn(II)-salicylidene–4–(p-chlorophenyl)–2–aminothiazole (SCAT) ligand was synthesized and studied in DMF media by the polarographic method and produce a DC and DPP polarogram in KCl (supporting electrolyte) with Britton- Robinson buffer. The far FT- IR spectral study show signals at 465 and 412 cm−1 respectively which confirm the metal-ligand bonding. The serial tube dilution method (MIC) was used for investigating the antibacterial activity of this newly synthesized complex and ligand toward pathogenic bacteria, B. subtilis, and E. coli. The results concluded that the ligand enhanced the biological activity when it binds with Zn(II) ion.