Anuj Kumar; Vinod Kumar Vashistha; Saeed Ahmed; Asif Ali; Dipak Kumar Das
Volume 12, Issue 7 , July 2020, , Pages 922-930
Abstract
The precise analysis of redox chemistry of MN4-based macrocyclic complexes is of great importance because of stabilization of unusual oxidation states of metal ions by macrocyclic ligand and thus have various applications in biochemistry, electrochemistry, electrocatalysis, pharmaceuticals etc. In this ...
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The precise analysis of redox chemistry of MN4-based macrocyclic complexes is of great importance because of stabilization of unusual oxidation states of metal ions by macrocyclic ligand and thus have various applications in biochemistry, electrochemistry, electrocatalysis, pharmaceuticals etc. In this work, MN4-macrocyclic complexes of Co (II) and Ni(II) transition metal ions have been synthesized by using template condensation method. Further, the MN4-macrocyclic complexes were characterized by elemental, molar conductance and multiple spectroscopic analysis. The spectral and elemental analysis suggested that both complexes would possess the saddle shape distorted octahedral geometry. Further, the electrochemical investigation of both complexes was carried out by cyclic voltammetry. Both complexes showed quasi-reversible one-electron transfer redox process indicating the stabilization of oxidation state of central metal ions. Moreover, the MN4-macrocyclic complexes have shown to have good antimicrobial activity against the various pathogens such as Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), Bacillus subtilis (B. subtilis) and Staphylococcus aureus (S. aureus).
ahmad khalaf alkhawaldeh
Volume 12, Issue 6 , June 2020, , Pages 780-792
Abstract
This study investigated the oxidation of ascorbic acid (Vitamin C) using a platinum nanoparticle electrode coated with an iodine monolayer, called a modified electrode. The electrode were grown using the cyclic voltammetry technique and the electrochemical measurements were taken using the cyclic voltammetry ...
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This study investigated the oxidation of ascorbic acid (Vitamin C) using a platinum nanoparticle electrode coated with an iodine monolayer, called a modified electrode. The electrode were grown using the cyclic voltammetry technique and the electrochemical measurements were taken using the cyclic voltammetry and chronoamperometric technique. In the case of platinum nanoparticle electrode modified iodine by and ascorbic acid, the analyzed the anodic peak current and anodic maximum potential is done. The also examined the effect of the concentration of ascorbic acid and the effect of the scan rate on anodic top parameters. The results show that the anodic current peak increases and that the anodic peak potentials increase in comparison to the clean electrode to a negative value. Anodic peak current increases with scan rate of ascorbic acid increases. As the ascorbic acid concentration and scan rate increase, the anodic peak potential changes to more positive values. The SEM and EDX demonstrate some fascinating characteristics of the uniform particle distribution, growth and self-assembly of the iodin-modified platinum nanoparticle. The sensor was ascorbic acid with a sensitivity of 0.215 μA/μM-cm2 and a detection limit of 0.01 μM (R2=0.994).The results show that the iodine-modified platinum nanoparticle electrode developed can be used in food sampling to voltammetric determine Vitamin C.
Sakina TOUZARA; Amina Amlil; Madiha Ennachete; Mohamed Amine Smaini; Abdelilah Chtaini
Volume 12, Issue 5 , May 2020, , Pages 644-652
Abstract
The method used to immobilize the polymer on the Disodium ethylenediamine tetraacetate (EDTA) modified carbon paste electrode (CPE/EDTA) has proved its effectiveness for the detection and chelation of heavy metals in aqueous solution. Its complex formation with Pb(II) was examined by square wave voltammetry ...
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The method used to immobilize the polymer on the Disodium ethylenediamine tetraacetate (EDTA) modified carbon paste electrode (CPE/EDTA) has proved its effectiveness for the detection and chelation of heavy metals in aqueous solution. Its complex formation with Pb(II) was examined by square wave voltammetry and cyclic voltammetry. CPE/EDTA electrodes are predisposed to the phenomenon of dissolution due to several factors, such as pH, we thought to cover these electrodes with a selective polymer synthesized (9% of the polysulfone and 91% of the polyacrylonitrile) for remedy this problem. It was found that the CPE/EDTA/polymer electrode shows a better performance than the carbon paste electrode modified by EDTA molecular (CPE/EDTA). The polymer used protects the surface of the electrode while preserving its activity. These modified electrodes developed in this study allow simple, rapid and inexpensive identifi1cation of lead ions with 1.08×10-9mol/l of detection limit. The morphological study of polymer surface was examined by Atomic Force Microscopy (AFM).
Milivoj Lovrić
Volume 12, Issue 5 , May 2020, , Pages 688-699
Abstract
Theoretical models of irreversible electro-oxidation of dissolved reactant giving dissolved product on the stationary planar electrode are developed for the conditions of staircase cyclic voltammetry. In the first model it is assumed that the product is adsorbed on the electrode surface and that the ...
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Theoretical models of irreversible electro-oxidation of dissolved reactant giving dissolved product on the stationary planar electrode are developed for the conditions of staircase cyclic voltammetry. In the first model it is assumed that the product is adsorbed on the electrode surface and that the adsorbate prevents the transfer of electrons. In the second model it is assumed that the electrode surface is reversibly covered by the oxide monolayer and that the product of electro-oxidation forms the inhibiting complex with the oxide. The calculations were performed by the transformation of transport defining differential equations into integral equations and by the numerical solution of the latter. The described mechanisms are investigated in order to analyse the relationship between the second anodic peak in cyclic voltammetry and the type of inhibition. It is shown that anomalous responses appear only if the electro-oxidation is inhibited by the surface complex of its product and the electrode oxide. The condition is that the electrode oxidation is reversible and that the complex disappears when the oxide is reduced.
Pemmatte A Pushpanjali; Jamballi G Manjunatha; Girish Tigari; Santosh Fattepur
Volume 12, Issue 4 , April 2020, , Pages 553-568
Abstract
In the current work, a novel sensor was developed for the analysis of Vanillin (VN) by electrochemical polymerization of Niacin over the surface of carbon nanotube paste electrode. The features of electrode surface was studied using Field Emission Scanning Electron Microscopy (FE‒SEM) images. Sweep ...
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In the current work, a novel sensor was developed for the analysis of Vanillin (VN) by electrochemical polymerization of Niacin over the surface of carbon nanotube paste electrode. The features of electrode surface was studied using Field Emission Scanning Electron Microscopy (FE‒SEM) images. Sweep rate variation study was conducted in the optimum pH (pH 7.0) for the evaluation of number of electrons involved in the electrochemical reaction and to investigate the mode of mass transfer phenomena. This investigation reveals that the electrode undergoes adsorption controlled mass transfer process. Based on the data obtained from the measurements the oxidation mechanism of VN was proposed. The prepared sensor was also applied for the simultaneous detection of VN and Caffeine (CF). Quantitative determination of VN was accomplished by cyclic voltammetric (CV) method. The corresponding value of limit of detection (LOD) and limit of quantification (LOQ) of VN was found to be 10.1×10-7 M and 3.3×10-6 M, respectively. In addition, the applicability of the proposed method was checked with the detection of VN in real sample with good recovery data.
Rubin Gulaboski; Pavlinka Kokoskarova; Sofija Petkovska
Volume 12, Issue 3 , March 2020, , Pages 345-364
Abstract
In this review, we focus on cyclic voltammetry as a reliable electrochemical technique to study mechanisms, kinetics and thermodynamics of various types of drug-drug interactions. While we present and discuss six theoretical models relevant to analyze drug-drug (or drug-DNA) interactions, we also give ...
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In this review, we focus on cyclic voltammetry as a reliable electrochemical technique to study mechanisms, kinetics and thermodynamics of various types of drug-drug interactions. While we present and discuss six theoretical models relevant to analyze drug-drug (or drug-DNA) interactions, we also give hints about recent experimental achievements in this field. In addition, we provide the readers several sets of simulated voltammograms and data in tabular form, which can be used to recognize particular mechanism of drug-drug interactions in cyclic voltammetry. Moreover, we give hints to the voltammetric procedures that allow access to kinetics and thermodynamics parameters, which are relevant to various types of drug-drug interactions. The results we present in this work can be of big help to the scientists working in the field of pharmacy, pharmacology, medicinal chemistry and bio-electrochemistry.
K. S. Ashoka; G. P. Mamatha; H. M. Santhosh
Volume 12, Issue 3 , March 2020, , Pages 415-424
Abstract
Isatins, derivatives of indole, represent important class of compounds belonging to nitrogen heterocycles. These compounds comprise synthetically vital substrates that are used as precursors for drug synthesis and raw materials for heterocycles etc. Research in this group of compounds has engrossed interest ...
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Isatins, derivatives of indole, represent important class of compounds belonging to nitrogen heterocycles. These compounds comprise synthetically vital substrates that are used as precursors for drug synthesis and raw materials for heterocycles etc. Research in this group of compounds has engrossed interest among scientific community in recent and past as Isatins are known to possess immense biological activities. Present work delineates synthesis, characterization, electrochemical and antimicrobial studies of four substituted derivatives of isatin derivatives. The cyclic voltammetric studies of all the analytes showed that four derivatives have better electro catalytic activity towards the analytes at glassy carbon electrode. These synthesized isatin derivatives were screened for their antimicrobial activity against Gram-negative bacteria (Escherichia coli and Staphylococcus aureus) and fungi such as Candida albicans and Penicillin chrysogenum, and found to possess considerable antimicrobial activity suggesting their effectiveness in developing antibiotics and novel drugs.
Hayat EL Ouafy; Tarik EL Ouafy; Mustapha Oubenali; Mohammed EL Idrissi; Malika Echajia; Aziz EL Haimouti; Mohamed Mbarki; Hassan Oulfajrite
Volume 12, Issue 2 , February 2020, , Pages 168-179
Abstract
Clay modified carbon paste electrode (CPE-C) its applicability for electroanalysis of N, N’-ethylene-2,2’-bipyridinium (diquat) has been described in the present work. Electrochemical modification was performed by electronic impedance spectroscopy (EIS) and cyclic voltammetry (CV) in the ...
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Clay modified carbon paste electrode (CPE-C) its applicability for electroanalysis of N, N’-ethylene-2,2’-bipyridinium (diquat) has been described in the present work. Electrochemical modification was performed by electronic impedance spectroscopy (EIS) and cyclic voltammetry (CV) in the range of -0.6 V to 1.2 V in 0.1 M K2SO4 (pH 3). The voltammetric method behavior of DQ is suggested where an anodic and cathodic peak appeared at Epa=0.55 V and Epc=0.1 V, successively. These peaks obtained from the reversible redox of DQ at the CPE-C surface. The optimal preconcentration time and percentage of clay insert were 10 min and 20% respectively. The proposed method exhibits certainly an electro-catalytic success toward DQ redox. The peaks current recorded using cyclic voltammetry has been linearly dependent on the DQ concentration ranging from 1×10-5 to 5×10-5 molL-1. The detection limit (DL) calculated for the anodic peak is 5.33×10-8 molL-1. Then relative standard deviation for 2×10-5 molL-1 diquat has been 4.3% for nine repetitions. The proposed detector has been successfully applied for DQ electroanalysis in a river water sample with a DL of 8.17×10-8 molL-1.
