Achievement of Near-Reversible Behavior for the [Fe(CN)6]3-/4-Redox Couple Using Cyclic Voltammetry at Glassy Carbon, Gold, and Platinum Macrodisk Electrodes in the Absence of Added Supporting Electrolyte

2000 ◽  
Vol 72 (15) ◽  
pp. 3486-3491 ◽  
Author(s):  
Melissa B. Rooney ◽  
Darren C. Coomber ◽  
Alan M. Bond
Keyword(s):  
Cyclic Voltammetry ◽  
Glassy Carbon ◽  
Supporting Electrolyte ◽  
Redox Couple

scholarly journals Electrochemical Oxidation of Paracetamol Mediated byMgB2Microparticles Modified Glassy Carbon Electrode

2011 ◽  
Vol 8 (2) ◽  
pp. 553-560 ◽  
Author(s):  
Mohammed Zidan ◽  
Tan Wee Tee ◽  
A. Halim Abdullah ◽  
Zulkarnain Zainal ◽  
Goh Joo Kheng
Keyword(s):  
Cyclic Voltammetry ◽  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Supporting Electrolyte ◽  
Carbon Electrode ◽  
Modified Glassy Carbon Electrode ◽  
Diffusion Controlled ◽  
Scan Rate ◽  
Degree Of Stability ◽  
A Current

A MgB2microparticles modified glassy carbon electrode (MgB2/GCE) was fabricated by adhering microparticles of MgB2onto the electrode surface of GCE. It was used as a working electrode for the detection of paracetamol in 0.1 M KH2PO4aqueous solution during cyclic voltammetry. Use of the MgB2/GCE the oxidation process of paracetamol with a current enhancement significantly by about 2.1 times. The detection limit of this modified electrode was found to be 30 μM. The sensitivity under conditions of cyclic voltammetry is significantly dependent on pH, supporting electrolyte, temperature and scan rate. The current enhancement observed in different electrolytic media varied in the following order: KH2PO4> KCl > K2SO4> KBr. Interestingly, the oxidation of paracetamol using modified GC electrode remain constant even after 15 cycling. It is therefore evident that the MgB2modifiedGCelectrode possesses some degree of stability. A slope of 0.52 dependent of scan rate on current indicates that the system undergoes diffusion-controlled process.

Determination of Drimarene Blue X-BLN at a glassy carbon electrode by differential pulse voltammetry

2011 ◽  
Vol 76 (12) ◽  
pp. 1765-1773 ◽  
Author(s):  
Abd-Elgawad M. Radi ◽  
Mohammed R. Mostafa ◽  
Reda M. Elshafey ◽  
Talaat A. Hegazy
Keyword(s):  
Differential Pulse Voltammetry ◽  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Supporting Electrolyte ◽  
Differential Pulse ◽  
Redox Couple ◽  
Carbon Electrode ◽  
Validation Parameters ◽  
Pulse Voltammetry

The electrochemical oxidation behaviour of Drimarene Blue X-BLN (DB) has been investigated in phosphate buffers (pH 2.54–10.18) by cyclic and differential pulse voltammetry (DPV) at a glassy carbon electrode (GCE). The oxidation of DB dye generated well-defined pH-dependent two pairs of quasi-reversible anodic-cathodic peak couples. DB exhibited the second redox couple over the entire pH range, while the first redox couple disappeared for pH ≥ 6.70. The redox processes were adsorption-controlled. An electroanalytical method was developed for the determination of DB in phosphate buffer solution (pH 2.85) as supporting electrolyte using DPV. The anodic current heights varied linearly with DB concentrations in the ranges 2 × 10–6–3 × 10–5 and 6 × 10–6–3 × 10–5 mol l–1 with limits of detection (LOD) of 8.7 × 10–7 and 5.7 × 10–7 mol l–1 and limits of quantification (LOQ) of 2.9 × 10–6 and 1.9 × 10–6 mol l–1 for the first and second anodic peaks, respectively. Validation parameters, such as accuracy, precision and recovery were evaluated. The proposed method was successfully applied to the determination of DB in tap water and the analytical results compared well with those obtained by the spectrophotometric method.

scholarly journals Novel cyclic voltammetry behavior of 3-((benzothiazol-2- diazenylnaphthalene-2,7-diol and use it for spectrophotometric determination of copper (II )in honey sample

2017 ◽  
Vol 12 (7) ◽  
pp. 4243-4255
Author(s):  
Fatma .A. Khazaal ◽  
Hussein. J. Mohammed ◽  
Muhammed . M.Radhi
Keyword(s):  
Cyclic Voltammetry ◽  
Spectrophotometric Determination ◽  
Glassy Carbon ◽  
Supporting Electrolyte ◽  
Honey Sample ◽  
Spectral Techniques ◽  
Scan Rate ◽  
Ft Ir ◽  
Determination Of Copper

The azo reagent 3-((benzothiazol-2-diazenylnaphthalene-2,7-diol] was synthesized and characterized by FT-IR ,1H-NMRand 13CNMR spectral techniques. The electrochemical behavior of the azo reagent and its complex with Cu (II) has beenstudied at glassy carbon disk GCE electrode in different supporting electrolyte at concentration (1M) and scan rate(100mv.s-1). Spectrophotometric determination of copper (II ) is based on the formation of a 2:1 complex with abovereagent. The complex has λmax at(588) nm and Ԑmax of( 1.436x104)L.mol-1.cm-1 .A linear correlation (0.1 – 3.0 μg. ml-1) was found between absorbance at λmax and concentration . The effect of diverseions on the determination of copper (II) to investigate the selectivity of the method were also studied . The stabilityconstant of the product was (1.1x108 ) . The proposed method was successfully applied to the analysis of honey sample .

Solar Exfoliated Graphene Oxide: A Platform for Electrochemical Sensing of Epinephrine

2020 ◽  
Vol 16 (4) ◽  
pp. 393-403 ◽  
Author(s):  
Renjini Sadhana ◽  
Pinky Abraham ◽  
Anithakumary Vidyadharan
Keyword(s):  
Cyclic Voltammetry ◽  
Graphene Oxide ◽  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Simultaneous Detection ◽  
Differential Pulse ◽  
Carbon Electrode ◽  
Modified Glassy Carbon Electrode ◽  
Reduced Graphene ◽  
Pulse Voltammetry

Introduction: In this study, solar exfoliated graphite oxide modified glassy carbon electrode was used for the anodic oxidation of epinephrine in a phosphate buffer medium at pH7. The modified electrode showed fast response and sensitivity towards Epinephrine Molecule (EP). The electrode was characterized electrochemically through Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV). Area of the electrode enhanced three times during modification and studies reveal that the oxidation process of EP occurs by an adsorption controlled process involving two electrons. The results showed a detection limit of 0.50 ± 0.01μM with a linear range up to 100 μM. The rate constant calculated for the electron transfer reaction is 1.35 s-1. The electrode was effective for simultaneous detection of EP in the presence of Ascorbic Acid (AA) and Uric Acid (UA) with well-resolved signals. The sensitivity, selectivity and stability of the sensor were also confirmed. Methods: Glassy carbon electrode modified by reduced graphene oxide was used for the detection and quantification of epinephrine using cyclic voltammetry and differential pulse voltammetry. Results: The results showed an enhancement in the electrocatalytic oxidation of epinephrine due to the increase in the effective surface area of the modified electrode. The anodic transfer coefficient, detection limit and electron transfer rate constant of the reaction were also calculated. Conclusion: The paper reports the determination of epinephrine using reduced graphene oxide modified glassy carbon electrode through CV and DPV. The sensor exhibited excellent reproducibility and repeatability for the detection of epinephrine and also its simultaneous detection of ascorbic acid and uric acid, which coexist in the biological system.

Zinc Electrodeposition in the Presence of an Aqueous Electrolyte Containing 1-Ethylpyridinium Bromide: Unexpected Oddities

2017 ◽  
Vol 70 (9) ◽  
pp. 1025 ◽  
Author(s):  
Max E. Easton ◽  
Lisa C. Player ◽  
Anthony F. Masters ◽  
Thomas Maschmeyer
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cyclic Voltammetry ◽  
Aqueous Electrolyte ◽  
Redox Couple ◽  
Nucleation Process ◽  
Zinc Electrodeposition ◽  
Unusual Behaviour ◽  
Scanning Electron

The reversible electrodeposition of zinc was investigated in an aqueous electrolyte containing zinc bromide (50 mM) and 1-ethylpyridinium bromide ([C2Py]Br, 50 mM) by cyclic voltammetry, chronoamperometry, and scanning electron microscopy. Unusual voltammetric behaviour for the Zn/ZnII redox couple was observed in the presence of [C2Py]Br. Passivation of the redox couple was observed after a single deposition–stripping cycle at switching potentials more negative than −1.25 V versus Ag/AgCl. This unusual behaviour was attributed to the reduction of 1-ethylpyridinium cations to pyridyl radicals and their follow-up reactions, which influenced the zinc electrochemistry. This behaviour was further seen to modify the nucleation process of electrodeposition, which altered the morphology of zinc electrodeposits.

scholarly journals Electrochemical Behaviour of a Gold Film- Glassy Carbon Electrode for Determination of Chromium (VI)

2021 ◽  
Author(s):  
Nevila Broli ◽  
Loreta Vallja ◽  
Majlinda Vasjari
Keyword(s):  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Electrochemical Behaviour ◽  
Supporting Electrolyte ◽  
Anodic Stripping Voltammetry ◽  
Carbon Electrode ◽  
Modulation Amplitude ◽  
Chromium Vi ◽  
Relative Standard

A gold nanostructured film modified glassy carbon electrode (Aufilm/GCE) was developed for the determination of chromium (VI) in water sample. GCE was immersed into HAuCl4 solution (10-3M) and electrodeposition of thin gold layer was conducted at –0.4 V (vs Ag/AgCl) for 10 min. The strong affinity between Au and Cr species resulted with increasing of Cr (VI) signal, compared with the bare glassy carbon electrode. The electrodepositing time, type of supporting electrolyte, pH, the scan rate, modulation amplitude, and modulation time were optimized using differential pulse anodic stripping voltammetry (DP-ASV). The calibration graph using accumulation time of 120 s was linear from 10 to 120 µgL-1 with a sensitivity 1.3 x 10-2 µA/µgL-1. Under optimum experimental conditions, a good correlation coefficient R2=0.9971, and a low detection limit 5.5 µg/L Cr (VI) was obtained. The signal was reproducible with a relative standard deviation ±4.5 %. The developed Aufilm/GCE sensor was applied for the Cr (VI) determination of in sewage water samples.

scholarly journals Nucleation/Growth and Optical Proprieties of Co-doped ZnO Electrodeposited on ITO Substrate

2021 ◽  
Vol 12 (5) ◽  
pp. 6776-6787
Keyword(s):  
Cyclic Voltammetry ◽  
Growth Mechanism ◽  
Supporting Electrolyte ◽  
Saturated Calomel Electrode ◽  
Nucleation And Growth ◽  
Visible Range ◽  
Zno Films ◽  
Doped Zno ◽  
Nucleation And Growth Mechanism ◽  
Co Doped

A Co-doped ZnO layer was prepared by electrodeposition method on indium doped tin oxide (ITO) substrate using a cathodic reduction from nitrate medium with different doping percentages of cobalt. The bath temperature was controlled at 70 °C. The films were cathodically electrodeposited in a bath containing 5 mM Zn(NO3)2. 6H2O, while the source of Co is Co(NO3)2.6H2O where 0.1M KNO3 was used as supporting electrolyte. The nucleation and growth mechanism of Co-doped ZnO nuclei have been studied by cyclic voltammetry and chronoamperometry. The cyclic voltammetry shows that the electrodeposition of ZnO and Co-doped ZnO at a negative potential around -1.0 V versus saturated calomel electrode (SCE) is a quasi-reversible reaction controlled by the diffusion process. Comparing current transients curves obtained by the chronoamperometric method with the theoretical curves of current density j versus t ½ allows us to say that the nucleation is 3D instantaneous, as shown in SEM analysis. The presence of Co does not modify the nucleation and growth mechanism. The XRD patterns show that the substitution of zinc by cobalt does not change the würtzite crystal structure, but the crystallite size decreases with the cobalt percentage. The transmittance spectra indicate that the Co-doped ZnO films are transparent in the visible range. The optical gap increases with the doping percentage of cobalt.

scholarly journals Effects of State of Charge on the Physical Characteristics of V(IV)/V(V) Electrolytes and Membrane for the All Vanadium Flow Battery

Batteries ◽  
2020 ◽  
Vol 6 (4) ◽  
pp. 49
Author(s):  
Wyndom S. Chace ◽  
Sophia M. Tiano ◽  
Thomas M. Arruda ◽  
Jamie S. Lawton
Keyword(s):  
Cyclic Voltammetry ◽  
Rotational Diffusion ◽  
Supporting Electrolyte ◽  
State Of Charge ◽  
Vanadium Redox Flow Battery ◽  
Bulk Solution ◽  
Flow Battery ◽  
Vanadium Concentration ◽  
H2so4 Concentration ◽  
Order Of Magnitude

The VO2+/VO2+ redox couple commonly employed on the positive terminal of the all-vanadium redox flow battery was investigated at various states of charge (SOC) and H2SO4 supporting electrolyte concentrations. Electron paramagnetic resonance was used to investigate the VO2+ concentration and translational and rotational diffusion coefficient (DT, DR) in both bulk solution and Nafion membranes. Values of DT and DR were relatively unaffected by SOC and on the order of 10−10 m2s−1. Cyclic voltammetry measurements revealed that no significant changes to the redox mechanism were observed as the state of charge increased; however, the mechanism does appear to be affected by H2SO4 concentration. Electron transfer rate (k0) increased by an order of magnitude (10−6 ms−1 to 10−8 ms−1) for each H2SO4 concentrations investigated (1, 3 and 5 M). Analysis of cyclic voltammetry switching currents suggests that the technique might be suitable for fast determination of state of charge if the system is well calibrated. Membrane uptake and permeability measurements show that vanadium absorption and crossover is more dependent on both acid and vanadium concentration than state of charge. Vanadium diffusion in the membrane is about an order of magnitude slower (~10−11 m2s−1) than in solution (~10−10 m2s−1).

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