International Journal of Electrochemistry http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Solvent Effects on the Electrochemical Behavior of TAPD-Based Redox-Responsive Probes for Cadmium(II) Tue, 25 Nov 2014 11:12:20 +0000 http://www.hindawi.com/journals/ijelc/2014/305721/ Two tetralkylated phenylenediamines (TAPD) 1 and 2 have been prepared by reductive alkylation of para-dimethylaminoaniline with furfural or thiophene 2-carboxaldehyde, respectively. Their chelation ability has been evaluated as electrochemical guest-responsive chemosensors for Cd(II) in acetonitrile (ACN), dimethylformamide (DMF), propylene carbonate (PC), and nitromethane (NM). The voltamperometric studies showed that these compounds are able to bind the Cd(II) cation with strong affinities except in DMF. The redox features of the chemosensors changed drastically when they are bounded to Cd(II) to undergo important anodic potential peak shifts comprised between ca. 500 and ca. 900 mV depending on the solvent. The addition of ∼4–10% molar triflic acid (TfOH) was found to be necessary to achieve rapidly the cation chelation which is slow without the acid. The electrochemical investigations suggested the formation of 1 : 2 stoichiometry complexes [Cd(L)2]2+. The results are discussed in terms of solvent effects as a competitive electron donating ligand to the cation. The reaction coupling efficiency (RCE) values were determined and were also found to be solvent-dependent. Rihab Sahli, Janet Bahri, Issa Tapsoba, Khaled Boujlel, and Noureddine Raouafi Copyright © 2014 Rihab Sahli et al. All rights reserved. Action of Chicory Fructooligosaccharides on Biomimetic Membranes Sun, 16 Nov 2014 11:48:27 +0000 http://www.hindawi.com/journals/ijelc/2014/186109/ Fructooligosaccharides from chicory (FOSC) are functional prebiotic foods recognized to exert several well-being effects in human health and animal production, as decreasing blood lipids, modulating the gut immune system, enhancing mineral bioavailability, and inhibiting microbial growth, among others. Mechanisms of actions directly on cell metabolism and structure are however little known. In this sense this work was targeted to investigate the interaction of FOSC with biomimetic membranes (liposomes and supported bilayer membrane; s-BLM) through cyclic voltammetry, impedance spectroscopy, spectrofluorimetry, and microscopy. FOSC was able to disrupt the membrane structure of liposomes and s-BLM from the onset of molecular pores induced on it. The mechanism of interaction of fructans with biomimetic membranes suggests hydrogen bonding between the polyhydroxylated structure of the oligosaccharides and the negative polar group of L--phosphatidylcholine (PC) present in both liposomes and s-BLM. A. F. Barbosa, R. S. Henrique, A. S. Lucho, V. Paffaro Jr., and J. M. Schneedorf Copyright © 2014 A. F. Barbosa et al. All rights reserved. Effect of Low Cobalt Loading on TiO2 Nanotube Arrays for Water-Splitting Sun, 09 Nov 2014 07:23:41 +0000 http://www.hindawi.com/journals/ijelc/2014/904128/ This work is intended to define a new possible methodology for the TiO2 doping through the use of an electrochemical deposition of cobalt directly on the titanium nanotubes obtained by a previous galvanostatic anodization treatment in an ethylene glycol solution. This method does not seem to cause any influence on the nanotube structure, showing final products with news and interesting features with respect to the unmodified sample. Together with an unmodified photoconversion efficiency under UV light, the cobalt doped specimen reports an increase of the electrocatalytic efficiency for the oxygen evolution reaction (OER). Alfonso Pozio Copyright © 2014 Alfonso Pozio. All rights reserved. Synthesis and Characterization of Electrodeposited C-PANI-Pd-Ni Composite Electrocatalyst for Methanol Oxidation Thu, 16 Oct 2014 14:42:07 +0000 http://www.hindawi.com/journals/ijelc/2014/383892/ Electropolymerization of aniline at the graphite electrodes was achieved by potentiodynamic method. Electrodeposition of Pd (C-PANI-Pd) and Ni (C-PANI-Ni) and codeposition of Pd-Ni (C-PANI-Pd-Ni) microparticles into the polyaniline (PANI) film coated graphite (C-PANI) were carried out under galvanostatic control. The morphology and composition of the composite electrodes were obtained using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) techniques. The electrochemical behavior and electrocatalytic activity of the electrode were characterized using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometric (CA) methods in acidic medium. The C-PANI-Pd-Ni electrode showed an improved catalytic performance towards methanol oxidation in terms of lower onset potential, higher anodic oxidation current, greater stability, lower activation energy, and lower charge transfer resistance. The enhanced electrocatalytic activity might be due to the greater permeability of C-PANI films for methanol molecules, better dispersion of Pd-Ni microparticles into the polymer matrixes, and the synergistic effects between the dispersed metal particles and their matrixes. S. S. Mahapatra, S. Shekhar, B. K. Thakur, and H. Priyadarshi Copyright © 2014 S. S. Mahapatra et al. All rights reserved. Role of Indium Alloying with Lead as a Means to Reduce the Passivation Phenomena in Lead/Acid Batteries Tue, 23 Sep 2014 00:00:00 +0000 http://www.hindawi.com/journals/ijelc/2014/932654/ The influence of indium content on the anodic behaviour of Pb-In alloys in 4 M H2SO4 solution is investigated by potentiodynamic, potentiostatic, chronopotentiometric, and cyclic voltammetric techniques. The composition and microstructure of the corrosion layer on Pb-In alloys are characterized by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy analysis (EDX), and scanning electron microscopy (SEM). The potentiodynamic and chronopotentiometric curves show that the anodic behavior of all investigated electrodes exhibits active/passive transition. The active dissolution (except for alloy I) and passive currents increase with increasing both In content and temperature. This indicates that the conductivity of the anodic film on Pb-In alloy is enhanced. This study exhibits that indium catalyses the oxidation of Pb (II) to Pb (IV) and facilitates the formation of a more highly conductive corrosion layer on lead. Alloy I (0.5% In) exhibits that the corrosion rate is lower, while the passive current is higher than that of Pb. XRD, EDX, and SEM results reveal that the formation of both PbSO4 and PbO on the surface decreases gradually with increasing In level in the alloy and completely disappear at higher In content (15% In). Therefore, recharge of the battery will be improved due to indium addition to Pb. Abdel-Rahman El-Sayed, Hossnia S. Mohran, and Hoda Abdel Shafy Shilkamy Copyright © 2014 Abdel-Rahman El-Sayed et al. All rights reserved. Using Poly-L-Histidine Modified Glassy Carbon Electrode to Trace Hydroquinone in the Sewage Water Mon, 08 Sep 2014 00:00:00 +0000 http://www.hindawi.com/journals/ijelc/2014/701284/ A sensitive voltammetric method for trace measurements of hydroquinone in the sewage water is described. The poly-L-histidine is prepared to modify the glassy carbon electrode in order to improve the electrochemical catalysis of interesting substances such as hydroquinone. The influence of the base solution, pH value, and scanning speed on the tracing of hydroquinone is discussed, and the experimental procedures and conditions are optimized. The laboratory results show that it is possible to construct a linear calibration curve between the peak current of hydroquinone on modified electrode and its concentration at the level of 0.00001 mol/L. The potential limitation of the method is suggested by a linear peaking shift model as well. The method was successfully applied to the determination of hydroquinone in the actual sample of industrial waste water. Bin Wang and Jun Steed Huang Copyright © 2014 Bin Wang and Jun Steed Huang. All rights reserved. Electron Transfer of Myoglobin Immobilized in Au Electrodes Modified with a RAFT PMMA-Block-PDMAEMA Polymer Sun, 31 Aug 2014 08:24:50 +0000 http://www.hindawi.com/journals/ijelc/2014/184206/ Myoglobin was immobilized with poly(methyl methacrylate)-block-poly[(2-dimethylamino)ethyl methacrylate]PMMA-block-PDMAEMA polymer synthesized by reversible addition-fragmentation chain transfer technique (RAFT). Cyclic voltammograms gave direct and slow quasireversible heterogeneous electron transfer kinetics between Mb-PMMA-block-PDMAEMA modified electrode and the redox center of the protein. The values for electron rate constant () and transfer coefficient () were ·s−1 and , respectively. The reduction potential determined as a function of temperature (293–328 K) revealed a value of reaction center entropy of of  J·mol−1·K−1 and enthalpy change of  kJ·mol−1, suggesting solvent effects and charge ionization atmosphere involved in the reaction parallel to hydrophobic interactions with the copolymer. The immobilized protein also exhibits an electrocatalytical response to reduction of hydrogen peroxide, with an apparent Km of  μM. The overall results substantiate the design and use of RAFT polymers towards the development of third-generation biosensors. Carla N. Toledo, Fábio H. Florenzano, and José M. Schneedorf Copyright © 2014 Carla N. Toledo et al. All rights reserved. Exploration of Electrochemical Intermediates of the Anticancer Drug Doxorubicin Hydrochloride Using Cyclic Voltammetry and Simulation Studies with an Evaluation for Its Interaction with DNA Sun, 03 Aug 2014 11:46:06 +0000 http://www.hindawi.com/journals/ijelc/2014/517371/ Electrochemical behavior of the anticancer drug doxorubicin hydrochloride was studied using cyclic voltammetry in aqueous medium using Hepes buffer (pH~7.4). At this pH, doxorubicin hydrochloride undergoes a reversible two-electron reduction with value − mV (versus Ag/AgCl, saturated KCl). Depending on scan rates, processes were either quasireversible (at low scan rates) or near perfect reversible (at high scan rates). This difference in behavior of doxorubicin hydrochloride with scan rate studied over the same potential range speaks of differences in electron transfer processes in doxorubicin hydrochloride. Attempt was made to identify and understand the species involved using simulation. The information obtained was used to study the interaction of doxorubicin hydrochloride with calf thymus DNA. Cathodic peak current gradually decreased as more calf thymus DNA was added. The decrease in cathodic peak current was used to estimate the interaction of the drug with calf thymus DNA. Nonlinear curve fit analysis was applied to evaluate the intrinsic binding constant and site size of interaction that was compared with previous results on doxorubicin hydrochloride-DNA interaction monitored by cyclic voltammetry or spectroscopic techniques. Partha Sarathi Guin and Saurabh Das Copyright © 2014 Partha Sarathi Guin and Saurabh Das. All rights reserved. Synthesis and Electrochemical Performance of LiMnPO4 by Hydrothermal Method Tue, 08 Jul 2014 07:19:54 +0000 http://www.hindawi.com/journals/ijelc/2014/768912/ LiMnPO4 with olivinestructure which is the promising candidate for high voltage cathode material was synthesized by hydrothermal method. In order to synthesize high purity and well-defined LiMnPO4, several precursors for Li, Mn, and P sources and hydrothermal reaction parameters including temperature and [H2O]/[Mn] value are optimized. By analyzing the structure, Mn valence, morphology, and chemical ratio via XRD, XPS, Raman, SEM, and ICP LiMnPO4 synthesized from manganese acetate tetrahydrate have single phase of LiMnPO4 without impurity and showed charge and discharge reaction caused by Mn2+/Mn3+ redox. Specific capacity of synthesized LiMnPO4 grew up during cycling. Moreover, when hydrothermal temperature was set at 150°C and [H2O]/[Mn] value was set at 15, discharge capacity as high as 70 mAh/g was obtained at rate. Daichi Fujimoto, Yu Lei, Zheng-Hong Huang, Feiyu Kang, and Junichi Kawamura Copyright © 2014 Daichi Fujimoto et al. All rights reserved. Synthesis of Nitrogen Doped Carbon and Its Enhanced Electrochemical Activity towards Ascorbic Acid Electrooxidation Thu, 26 Jun 2014 13:31:17 +0000 http://www.hindawi.com/journals/ijelc/2014/246746/ Nitrogen doped carbon, synthesized by a novel way of carbonizing polyaniline in an inert atmosphere at a constant temperature of , exhibits several unique features. The carbon: nitrogen ratio is found to increase with the treatment duration up to 120 minutes and a mass reduction of 60 wt% is observed with an interesting observation of the retention of the bulk polymer morphology, surprisingly, even after the carbonization process. The electrochemical activity evaluated with potassium hexacyanoferrate and hexamine ruthenium redox systems at a regular time interval helps to tune the catalytic activity. This type of nitrogen doped carbon prepared from polyaniline base exhibits excellent electrocatalytic activity as illustrated by the oxidation of ascorbic acid in neutral medium. Sankararao Mutyala and Mathiyarasu Jayaraman Copyright © 2014 Sankararao Mutyala and Mathiyarasu Jayaraman. All rights reserved. Pd-Au Electrocatalysts for Hydrogen Evolution Reaction at Neutral pH Mon, 31 Mar 2014 12:12:23 +0000 http://www.hindawi.com/journals/ijelc/2014/239270/ Pd-Au codeposits with different ratio of both metals were electrodeposited on carbon felt, characterized by scanning electron microscopy, and investigated as electrocatalysts towards hydrogen evolution reaction in neutral phosphate buffer solution. The quantities of the produced hydrogen gas with different electrocatalysts, estimated from data obtained by chronoamperometry, were confirmed by mass spectrometry analysis. The highest hydrogen evolution rate was achieved with the electrocatalysts, produced from electrolyte with equal Pd and Au content. Elitsa Chorbadzhiyska, Mario Mitov, Georgi Hristov, Nina Dimcheva, Lori Nalbandian, Antigoni Evdou, and Yolina Hubenova Copyright © 2014 Elitsa Chorbadzhiyska et al. All rights reserved. Development of Membraneless Sodium Perborate Fuel Cell for Media Flexible Power Generation Thu, 27 Mar 2014 11:52:25 +0000 http://www.hindawi.com/journals/ijelc/2014/962161/ This paper reports the media flexibility of membraneless sodium perborate fuel cell (MLSPBFC) using acid/alkaline bipolar electrolyte in which the anode is in acidic media while the cathode is in alkaline media, or vice versa. Investigation of the cell operation is conducted by using formic acid as a fuel and sodium perborate as an oxidant for the first time under “acid-alkaline media” configurations. The MLSPBFC architecture enables interchangeable operation with different media combinations. The experimental results indicate that operating under “acid-alkaline media” conditions significantly improves the fuel cell performance compared with all-acidic and all-alkaline conditions. The effects of flow rates and the concentrations of various species at both the anode and cathode on the cell performance are also investigated. It has been demonstrated that the laminar flow based microfluidic membraneless fuel cell can reach a maximum power density of 28.2 mW cm−2 with a fuel mixture flow rate of 0.3 mL min−1 at room temperature. K. Ponmani, S. Durga, A. Arun, S. Kiruthika, and B. Muthukumaran Copyright © 2014 K. Ponmani et al. All rights reserved. Isomers of Poly Aminophenol: Chemical Synthesis, Characterization, and Its Corrosion Protection Aspect on Mild Steel in 1 M HCl Mon, 17 Mar 2014 06:30:28 +0000 http://www.hindawi.com/journals/ijelc/2014/961617/ The oxidative chemical polymerizations of three isomers of aminophenol, ortho, meta, and para (PoAP, PmAP, and PpAP), were performed in aqueous HCl using ammonium persulfate as an oxidant at 0–3°C. The synthesized polymers were characterized by employing elemental analysis, GPC, UV-VIS-NIR, FT-IR, XRD, and TGA. The corrosion inhibition effect of these three polymers on mild steel in 1 M HCl solution was studied by using electrochemical techniques such as potentiodynamic polarization and electrochemical impedance spectroscopy. These measurements reveal that the inhibition efficiency obtained by these polymers increased by increasing their concentration. The inhibition efficiency follows the order PpAP > PoAP > PmAP. The results further revealed that PpAP at a concentration of 250 mg/L furnishes maximum inhibition efficiency (96.5%). Polarization studies indicated that these three polymers act as the mixed type corrosion inhibitors. G. Thenmozhi, P. Arockiasamy, and R. Jaya Santhi Copyright © 2014 G. Thenmozhi et al. All rights reserved. Electroanalytical Methodology for the Direct Determination of 2,4-Dichlorophenoxyacetic Acid in Soil Samples Using a Graphite-Polyurethane Electrode Sun, 16 Mar 2014 13:08:57 +0000 http://www.hindawi.com/journals/ijelc/2014/308926/ An electroanalytical methodology was developed for the direct determination of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) using a graphite-polyurethane composite electrode and square wave voltammetry (SWV). 2,4-D exhibited one reduction peak with characteristics of an irreversible process at −0.54 V (versus Ag/AgCl), which is controlled by the diffusion of the reagent on the electrode surface. After the experimental parameters optimization (pH 2.0,  s−1,  V, and  V), analytical curves were constructed in the range of 0.66 mg L−1 to 2.62  mg L−1. Detection (LD) and quantification (LQ) limits were 17.6 g L−1 and 58.6 g L−1, respectively. The methodology was successfully applied to measure the percolation of the herbicide 2,4-D in undisturbed soil columns of different granulometric compositions. Fernanda Ramos de Andrade, Renata Alves de Toledo, and Carlos Manoel Pedro Vaz Copyright © 2014 Fernanda Ramos de Andrade et al. All rights reserved. The Corrosion Behaviour of WC-Co-Ru Alloys in Aggressive Chloride Media Thu, 27 Feb 2014 07:34:45 +0000 http://www.hindawi.com/journals/ijelc/2014/594871/ Hardmetals possess excellent wear resistance, making them suitable alloys in several industrial applications. Mine waters with both dissolved chloride and sulphate salts can be severely corrosive and can limit the application of hardmetal tools in the mining industry. Ru additions to these alloys can refine and improve selected mechanical properties, but its influence on the corrosion resistance is unknown. A series of WC-Co-Ru alloys was evaluated in different chloride containing media to investigate their corrosion resistance. Standard electrochemical corrosion tests, chronoamperometric measurements, and surface analyses with Raman spectroscopy were conducted. An increasing amount of Ru improves the corrosion resistance of all the alloys. The effect is not as dramatic as that observed with stainless steels containing Ru in corrosive media. In both corrosive media Ru decreased the cathodic Tafel constant and has a retarding influence on the cathodic part of the corrosion reaction. Raman analyses indicated the presence of tungsten oxide, hydrated tungsten oxide compounds, and CoO and Co3O4 formed on the alloy surfaces during the corrosion process. J. H. Potgieter, P. Olubambi, and S. S. Potgieter-Vermaak Copyright © 2014 J. H. Potgieter et al. All rights reserved. Power Generation from Human Leukocytes/Lymphocytes in Mammalian Biofuel Cell Mon, 30 Dec 2013 18:34:39 +0000 http://www.hindawi.com/journals/ijelc/2013/706792/ Alternative to batteries power sources is needed for the human implants of the future that tend to be less invasive and more integrated to human biology and physiology. Human metabolism could be exploited for the generation of power, but mammalian cells protect their energy production apparatus from external electrochemical scavengers. We report here evidence that, in the case of white blood cells, chemical energy can be harvested directly on an electrode as electricity in fuel cells whose stability is roughly parallel to the viability of cells in vitro. Electrochemical activity of human leukocytes immobilized on modified carbon mesh electrodes was investigated by cyclic voltammetry. Oxidation peaks at 0.33 V versus Ag/AgCl were observed. An open-circuit potential of 0.44 V was recorded between anode and cathode compartments where the biofuel cell potential operating under an external load of 5 kΩ was below 0.35 V. Average power outputs of 10 μW ( μW/cell) were increased to 15 μW by the activation of white blood cells. Power densities of 1.5 μW cm−2 for lower than physiological cell concentrations are low for most of today’s implants, but possibility of cell immobilization allows a positive outlook for the future utility of the reported findings. Güray Güven, Pablo Lozano-Sanchez, and Arcan Güven Copyright © 2013 Güray Güven et al. All rights reserved. Electrochemical and Spectroscopic Characterization of Aluminium(III)-para-methyl-meso-tetraphenylporphyrin Complexes Containing Substituted Salicylates as Axial Ligands Mon, 30 Dec 2013 11:44:58 +0000 http://www.hindawi.com/journals/ijelc/2013/409375/ A series of aluminium(III)-p-methyl-meso-tetraphenylporphyrin (p-CH3TPP-Al(III)) containing axially coordinated salicylate anion [p-CH3TPP-Al-X)], where X = salicylate (SA), 4-chlorosalicylate (4-CSA), 5-chlorosalicylate (5-CSA), 5-flourosalicylate (5-FSA), 4-aminosalicylate (4-ASA), 5-aminosalicylate (5-ASA), 5-nitrosalicylate (5-NSA), and 5-sulfosalicylate (5-SSA), have been synthesized and characterized by various spectroscopic techniques including ultraviolet-visible (UV-vis), infrared (IR) spectroscopy, proton nuclear magnetic resonance (1H NMR) spectroscopy, 13C NMR, and elemental analysis. A detailed study of electrochemistry of all the synthesized compounds has been done to compare their oxidation and reduction mechanisms and to explain the effect of axial coordination on their redox properties. Gauri D. Bajju, Deepmala, Sunil Kumar Anand, Sujata Kundan, and Narinder Singh Copyright © 2013 Gauri D. Bajju et al. All rights reserved. Analytical Expressions for Steady-State Concentrations of Substrate and Oxidized and Reduced Mediator in an Amperometric Biosensor Tue, 24 Dec 2013 13:18:47 +0000 http://www.hindawi.com/journals/ijelc/2013/812856/ A mathematical model of modified enzyme-membrane electrode for steady-state condition is discussed. This model contains a nonlinear term related to enzyme kinetics reaction mechanism. The thickness dependence of an amperometric biosensor is presented both analytically and numerically where the biological layer is immobilized between a solid substrate and permeable electrode. The analytical expressions pertaining to the concentration of species and normalized current are obtained using the Adomian decomposition method (ADM). Simple and approximate polynomial expressions of concentrations of an oxidized mediator, substrate, and reduced mediator are derived for all possible values of parameters (Thiele modulus), (normalized surface concentration of oxidized mediator), and (normalized surface concentration of substrate). A comparison of the analytical approximation and numerical simulation is also presented. A good agreement between theoretical predictions and numerical results is observed. Loghambal Shunmugham and L. Rajendran Copyright © 2013 Loghambal Shunmugham and L. Rajendran. All rights reserved. Square Wave Voltammetric Determination of 2-Thiouracil in Pharmaceuticals and Real Samples Using Glassy Carbon Electrode Tue, 24 Dec 2013 11:05:44 +0000 http://www.hindawi.com/journals/ijelc/2013/627854/ A simple and rapid method was developed using cyclic and square wave voltammetric techniques for the determination of trace-level sulfur containing compound, 2-thiouracil, at a glassy carbon electrode. 2-thiouracil produced two anodic peaks at 0.334 V and 1.421 V and a cathodic peak at −0.534 V. The square wave voltammetry of 2-thiouracil gave a good linear response in the range of 1–20 μM with a detection limit of 0.16 μM and quantification limit of 0.53 μM (0.0679 μg/g), which is in good agreement as per IUPAC definition of trace component analysis (100 μg/g). The obtained recoveries range from 98.10% to 102.1%. The proposed method was used successfully for its quantitative determination in pharmaceutical formulations and urine as real samples. Naveen M. Gokavi, Vijay P. Pattar, Atmanand M. Bagoji, and Sharanappa T. Nandibewoor Copyright © 2013 Naveen M. Gokavi et al. All rights reserved. Faster-Than-Real-Time Simulation of Lithium Ion Batteries with Full Spatial and Temporal Resolution Tue, 24 Dec 2013 08:56:55 +0000 http://www.hindawi.com/journals/ijelc/2013/268747/ A one-dimensional coupled electrochemical-thermal model of a lithium ion battery with full temporal and normal-to-electrode spatial resolution is presented. Only a single pair of electrodes is considered in the model. It is shown that simulation of a lithium ion battery with the inclusion of detailed transport phenomena and electrochemistry is possible with faster-than-real-time compute times. The governing conservation equations of mass, charge, and energy are discretized using the finite volume method and solved using an iterative procedure. The model is first successfully validated against experimental data for both charge and discharge processes in a battery. Finally, it is demonstrated for an arbitrary rapidly changing transient load typical of a hybrid electric vehicle drive cycle. The model is able to predict the cell voltage of a 15-minute drive cycle in less than 12 seconds of compute time on a laptop with a 2.33 GHz Intel Pentium 4 processor. Sandip Mazumder and Jiheng Lu Copyright © 2013 Sandip Mazumder and Jiheng Lu. All rights reserved. Electrochemical Studies of Betti Base and Its Copper(II) Complex by Cyclic and Elimination Voltammetry Sun, 22 Dec 2013 13:59:50 +0000 http://www.hindawi.com/journals/ijelc/2013/678013/ The electrochemical behavior of Betti base 1-(α-amino benzyl)-2-naphthol (BB) and its copper(II) complex by cyclic and elimination voltammetry (EVLS) is reported in the present study. The cyclic voltammetric studies carried out at a glassy carbon working electrode, Ag/Ag+ reference electrode (0.01 M AgNO3 in acetonitrile) in DCM at 100 mV/sec, 200 mV/sec, and 400 mV/sec scan rates indicated a preceding chemical oxidation of the adsorbed BB species to form an iminium ion followed by formation of a carbanion via two-step quasireversible reduction. The suggested reaction mechanism has been supported by the elimination voltammetry. The CV and EVLS studies revealed Cu(II)BB complex to undergo a chemical or a surface reaction before electron transfer from the electrode at −0.49 V to form Cu(I)BB species. The oxidation of Cu(I)BB species has been observed to be CV silent. Shardul Bhatt and Bhavna Trivedi Copyright © 2013 Shardul Bhatt and Bhavna Trivedi. All rights reserved. Electrochemical Sandwich Immunoassay for the Ultrasensitive Detection of Human MUC1 Cancer Biomarker Sun, 22 Dec 2013 10:22:38 +0000 http://www.hindawi.com/journals/ijelc/2013/740265/ A new electrochemical sandwich immunoassay for the ultrasensitive detection of human MUC1 cancer biomarker using protein G-functionalized magnetic beads (MBs) and graphite-based screen-printed electrodes (SPEs) was developed. Magnetic beads were employed as the platforms for the immobilization and immunoreaction process. A pair of primary and secondary antibodies was used to capture the MUC1 protein. After labeling with a third antibody conjugated with horseradish peroxidase (HRP), the resulting conjugate was trapped at the surface of the graphite-based SPEs and MUC1 determination was carried out by differential pulse voltammetry (DPV) at 0.4 V upon H2O2 addition using acetaminophen (APAP) as the redox mediator. A linear relationship was obtained for the detection of human MUC1 over a range of 0–25 ppb with the lowest detection limit of 1.34 ppb when HRP was applied as a label. Preliminary experiments were performed using disposable electrochemical sensors in order to optimize some parameters (i.e., incubation times, concentrations, and blocking agent). Zahra Taleat, Cecilia Cristea, Giovanna Marrazza, and Robert Săndulescu Copyright © 2013 Zahra Taleat et al. All rights reserved. Cyclic Voltammetric Investigation of Caffeine at Anthraquinone Modified Carbon Paste Electrode Tue, 17 Dec 2013 14:54:16 +0000 http://www.hindawi.com/journals/ijelc/2013/849327/ Electrochemical methods have been widely used for the determination of electroactive compounds due to their simplicity, sensitivity, stability, and low cost. A carbon paste electrode was modified with anthraquinone. Cyclic voltammetry (CV) was employed to study the properties of the modified electrode toward the oxidation of caffeine (CAF). Compared to the unmodified electrode, the AQMCPE showed excellent catalytic activity for the oxidation of caffeine. AQMCPE was used to determine CAF in drug samples electrochemically. SWV was used to plot the calibration curve and there was a good linear relationship between anodic peak current and CAF concentration in the range  M, with the correlation coefficient of 0.998 and a detection limit of  M. The application of the modified electrode for the determination of CAF in pharmaceutical formulation showed good recovery with reproducible results. Yemane Tadesse, Abraha Tadese, R. C. Saini, and Rishi Pal Copyright © 2013 Yemane Tadesse et al. All rights reserved. Ion Dynamics Study of Potato Starch + Sodium Salts Electrolyte System Wed, 11 Dec 2013 12:14:00 +0000 http://www.hindawi.com/journals/ijelc/2013/670914/ The effect of different anions, namely, , , and , on the electrical properties of starch-based polymer electrolytes has been studied. Anion size and conductivity are having an inverse trend indicating systems to be predominantly anionic conductor. Impact of anion size and multiplet forming tendency is reflected in number of charge carriers and mobility, respectively. Ion dynamics study reveals the presence of different mechanisms in different frequency ranges. Interestingly, superlinear power law (SLPL) is found to be present at <5 MHz frequency, which is further confirmed by dielectric data. Tuhina Tiwari, Neelam Srivastava, and P. C. Srivastava Copyright © 2013 Tuhina Tiwari et al. All rights reserved. Influence of Bath Composition at Acidic pH on Electrodeposition of Nickel-Layered Silicate Nanocomposites for Corrosion Protection Wed, 20 Nov 2013 18:48:35 +0000 http://www.hindawi.com/journals/ijelc/2013/853869/ Nickel-layered silicates were electrochemically deposited from acidic bath solutions. Citrate was used as a ligand to stabilize nickel (II) ions in the plating solution. The silicate, montmorillonite, was exfoliated by stirring in aqueous solution over 24 hours. The plating solutions were analyzed for zeta-potential, particle size, viscosity, and conductivity to investigate the effects of the composition at various pHs. The solution particles at pH 2.5 (−22.2 mV) and pH 3.0 (−21.9 mV) were more stable than at pH 1.6 (−10.1 mV) as shown by zeta-potential analysis of the nickel-citrate-montmorillonite plating solution. for the films ranged from −0.32 to −0.39 V with varying pH from 1.6 to 3.0. The films were immersed in 3.5% NaCl and the open circuit potential monitored for one month. The coatings deposited at pH 3.0 were stable 13 days longer in the salt solution than the other coatings. X-ray diffraction showed a change in the (111)/(200) ratio for the coatings at the various pHs. The scanning electron microscopy and hardness results also support that the electrodeposition of nickel-montmorillonite at pH 3.0 (234 GPa) had improved hardness and morphology compared to pH 2.5 (174 GPa) and pH 1.6 (147 GPa). Jeerapan Tientong, Casey R. Thurber, Nandika D’Souza, Adel Mohamed, and Teresa D. Golden Copyright © 2013 Jeerapan Tientong et al. All rights reserved. Electrodeposition of Oriented Cerium Oxide Films Sun, 27 Oct 2013 10:19:50 +0000 http://www.hindawi.com/journals/ijelc/2013/482187/ Cerium oxide films of preferred orientation are electrodeposited under anodic conditions. A complexing ligand, acetate, was used to stabilize the cerium (III) ion in solution for deposition of the thin films. Fourier transform infrared spectroscopy showed that the ligand and metal tended to bind as a weakly bidentate complex. The crystallite size of the films was in the nanometer range as shown by Raman spectroscopy and was calculated from X-ray diffraction data. Crystallite sizes from 6 to 20 nm were obtained under the anodic deposition conditions. Sintering of the (111) oriented films showed an increase in the (111) orientation with temperatures up to 900°C. Also, the crystallite size increased from 20 nm to 120 nm under sintering conditions. Addition of the deposited films to the substrate improved corrosion resistance for the substrate. Adele Qi Wang and Teresa D. Golden Copyright © 2013 Adele Qi Wang and Teresa D. Golden. All rights reserved. Electrochemical Characterization of Platinum Nanotubules Made via Template Wetting Nanofabrication Thu, 24 Oct 2013 17:28:29 +0000 http://www.hindawi.com/journals/ijelc/2013/960513/ Standard oxidation-reduction reactions such as those of ferrocyanide and ferrocene have long been employed in evaluating and comparing new electrode structures with more traditional configurations. A variety of nanostructured carbon electrodes developed in recent years have been reported to exhibit faster electron transfer kinetics than more traditional carbon structures when studied with these redox reactions. This type of comparison has not been widely explored for nanostructured platinum electrodes that have become increasingly common. In this work, a platinum nanotubule array electrode was fabricated via a simple template-based process and evaluated using the standard ferrocyanide redox reaction. The nanotubule array electrodes were observed to more closely approach ideal reversible behavior than a typical Pt black/Nafion fuel cell electrode or a standard polished Pt disc electrode. The apparent heterogeneous electron transfer coefficient was determined using the Nicholson method and found to be one to two orders of magnitude greater for the nanotubule array electrodes, depending on the diameter of the nanotubules, in comparison with these same two more traditional electrode structures. Eric Broaddus, Joel Brubaker, and Scott A. Gold Copyright © 2013 Eric Broaddus et al. All rights reserved. Fast Switching Electrochromic Devices Containing Optimized BEMA/PEGMA Gel Polymer Electrolytes Mon, 07 Oct 2013 09:12:35 +0000 http://www.hindawi.com/journals/ijelc/2013/138753/ An optimized thermoset gel polymer electrolyte based on Bisphenol A ethoxylate dimethacrylate and Poly(ethylene glycol) methyl ether methacrylate (BEMA/PEGMA) was prepared by facile photo-induced free radical polymerisation technique and tested for the first time in electrochromic devices (ECD) combining WO3 sputtered on ITO as cathodes and V2O5 electrodeposited on ITO as anodes. The behaviour of the prepared ECD was investigated electrochemically and electro-optically. The ECD transmission spectrum was monitored in the visible and near-infrared region by varying applied potential. A switching time of ca. 2 s for Li+ insertion (coloring) and of ca. 1 s for Li+ de-insertion (bleaching) were found. UV-VIS spectroelectrochemical measurements evidenced a considerable contrast between bleached and colored state along with a good stability over repeated cycles. The reported electrochromic devices showed a considerable enhancement of switching time with respect to the previously reported polymeric ECD indicating that they are good candidates for the implementation of intelligent windows and smart displays. N. Garino, S. Zanarini, S. Bodoardo, J. R. Nair, S. Pereira, L. Pereira, R. Martins, E. Fortunato, and N. Penazzi Copyright © 2013 N. Garino et al. All rights reserved. A Dopamine Sensor Based on Pre-Concentration by Magnetic Nanoparticles Mon, 30 Sep 2013 11:23:14 +0000 http://www.hindawi.com/journals/ijelc/2013/803672/ Herein, Fe3O4 magnetic nanoparticles (MNPs) were synthesized and characterized. Afterward, a magnetic carbon paste electrode (MCPE) was modified with MNPs via casting and drying MNPs on top of the MCPE (MCPE/MNP). Electrochemical behavior of the MCPE/MNP was studied by cyclic voltammetry in the presence of [Fe(CN)6]3−/4− as a redox probe, and surface of MNPs was evaluated as . The behavior of MCPE/MNP towards dopamine (DA) and ascorbic acid (AA) has been investigated by electrochemical methods, and the obtained results showed that the MCPE/MNP has adsorption behavior towards only DA. Based on this behavior, the DA molecules were pre-concentrated on top of the MCPE/MNP and followed with stripping in DA free solution. Subsequent to experimental and instrumental optimization, a calibration curve from to  M DA with , DL =  M DA, and RSD = 4.6%, was obtained in the presence of  M AA. Performance of the MCPE/MNP was successfully tested in a pharmaceutical sample. Mojtaba Bagherzadeh, Somayeh Ansari, Fariborz Riahi, and Anahita Farahbakhsh Copyright © 2013 Mojtaba Bagherzadeh et al. All rights reserved. Voltammetry Study of an Anti-HIV Compound by means of a Thin Organic Membrane Tue, 24 Sep 2013 10:47:07 +0000 http://www.hindawi.com/journals/ijelc/2013/902872/ Cyclic and square wave voltammetries have been used to study electrochemical behaviour of an anti-HIV agent (Guttiferone A) at the liquid-liquid interface. The thin organic membrane is formed by an organic solvent containing redox probe. Guttiferone A, a benzophenone (BP) with appropriate electrolyte. It is demonstrated that BP possesses three reduction systems due to the redox transformation of the three tautomeric forms that lead to the migration of proton between the hydroxyl group in position 4 and the carbonyl group in positions 2 and 10. The transfer of proton from the aqueous solution to the organic phase is crucial for the redox transformation of BP into the organic membrane. The voltammograms obtained are strongly influenced by the pH of the aqueous phase. The electrochemical mechanism consists of 2e−/2H+ exchange to form the separate redox compound BPH2. Achille Nassi, Thiery Christophe Ebelle, Joseph M. Dika Manga, Jules-Blaise Mabou Leuna, Joel Donkeng Dazie, and Emmanuel Ngameni Copyright © 2013 Achille Nassi et al. All rights reserved.