scholarly journals Cyclic Voltammetric Investigations of Thiazine Dyes on Modified Electrodes

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Amitabha Chakraborty ◽  
Shamsuzzaman Ahamed ◽  
Subrata Pal ◽  
Swapan K. Saha
Keyword(s):  
Diffusion Coefficient ◽  
Modified Electrode ◽  
Glassy Carbon ◽  
Electrochemical Behavior ◽  
Modified Electrodes ◽  
Electron Hopping ◽  
Cyclic Voltammetric ◽  
Peak Current ◽  
Quantitative Characteristics ◽  
Thiazine Dyes

Electrochemical behavior of five progressively alkylated thiazine dyes has been investigated at glassy carbon/montmorillonite and glassy carbon/zeolite electrodes. Quantitative characteristics, associated with the positions of peak potentials (Ea and Ec) and current ratios (ia/ic), are measured with scan rates. The peak current observed in the modified electrodes is dependent on both the porosity and nature and number of sites involved in partitioning the complex into film. The values of diffusion coefficient for different dyes have been calculated from electrochemical data. It is suggested that in clay-modified electrode along with physical diffusion the process of electron hopping seems to be most likely.

scholarly journals Electrochemical determination of ascorbic acid at p-phenylenediamine film-holes modified glassy carbon electrode

2015 ◽  
Vol 80 (9) ◽  
pp. 1161-1175 ◽  
Author(s):  
Bikila Olana ◽  
Shimeles Kitte ◽  
Tesfaye Soreta
Keyword(s):  
Ascorbic Acid ◽  
Detection Limit ◽  
Glassy Carbon Electrode ◽  
Modified Electrode ◽  
Glassy Carbon ◽  
Linear Response ◽  
Modified Electrodes ◽  
Electrochemical Determination ◽  
Carbon Electrode

In this work the determination of ascorbic acid (AA) at glassy carbon electrode (GCE) modified with a perforated film produced by reduction of diazonium generated in situ from p-phenylenediamine (PD) is reported. Holes were intentionally created in the modifier film by stripping a pre-deposited gold nanoparticles. The modified electrodes were electrochemically characterized by common redox probes: hydroquinone, ferrocyanide and hexamineruthenium(III). The cyclic voltammetric and amperometric response of AA using the modified electrodes was compared with that of bare GCE. The bare GCE showed a linear response to AA in the concentration range of 5 mM to 45 mM with detection limit of 1.656 mM and the modified GCE showed a linear response to AA in the concentration range of 5 ?M to 45 ?M with detection limit of 0.123 ?M. The effect of potential intereferents on amperometric signal of AA at the modified GCE was examined and found to be minimal. The inter-electrode reproducibility, stability, and accuracy were determined. The modified electrode showed excellent inter-electrode reproducibility, accuracy and stability. The modified electrode reported is a promising candidate for use in electroanalysis of AA.

scholarly journals Peroxide Electrochemical Sensor and Biosensor Based on Nanocomposite of TiO2 Nanoparticle/Multi-Walled Carbon Nanotube Modified Glassy Carbon Electrode

Nanomaterials ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 64 ◽  
Author(s):  
L. Andrés Guerrero ◽  
Lenys Fernández ◽  
Gema González ◽  
Marjorie Montero-Jiménez ◽  
Rafael Uribe ◽  
...  
Keyword(s):  
Modified Electrode ◽  
Glassy Carbon ◽  
Sodium Dodecylsulfate ◽  
Modified Electrodes ◽  
Dimethyl Formamide ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Before And After ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

A hydrogen peroxide (H2O2) sensor and biosensor based on modified multi-walled carbon nanotubes (CNTs) with titanium dioxide (TiO2) nanostructures was designed and evaluated. The construction of the sensor was performed using a glassy carbon (GC) modified electrode with a TiO2–CNT film and Prussian blue (PB) as an electrocalatyzer. The same sensor was also employed as the basis for H2O2 biosensor construction through further modification with horseradish peroxidase (HRP) immobilized at the TiO2–fCNT film. Functionalized CNTs (fCNTs) and modified TiO2–fCNTs were characterized by Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), and X-Ray DifFraction (XRD), confirming the presence of anatase over the fCNTs. Depending on the surface charge, a solvent which optimizes the CNT dispersion was selected: dimethyl formamide (DMF) for fCNTs and sodium dodecylsulfate (SDS) for TiO2–fCNTs. Calculated values for the electron transfer rate constant (ks) were 0.027 s−1 at the PB–fCNT/GC modified electrode and 4.7 × 10−4 s−1 at the PB–TiO2/fCNT/GC electrode, suggesting that, at the PB–TiO2/fCNT/GC modified electrode, the electronic transfer was improved. According to these results, the PB–fCNT/GC electrode exhibited better Detection Limit (LD) and Quantification Limit (LQ) than the PB–TiO2/fCNT/GC electrode for H2O2. However, the PB film was very unstable at the potentials used. Therefore, the PB–TiO2/fCNT/GC modified electrode was considered the best for H2O2 detection in terms of operability. Cyclic Voltammetry (CV) behaviors of the HRP–TiO2/fCNT/GC modified electrodes before and after the chronoamperometric test for H2O2, suggest the high stability of the enzymatic electrode. In comparison with other HRP/fCNT-based electrochemical biosensors previously described in the literature, the HRP–fCNTs/GC modified electrode did not show an electroanalytical response toward H2O2.

Trace Determination of Lead and Cadmium using Graphene/[Ru(NH3)6]3+/Nafion Modi-fied Glassy Carbon Electrodes

2017 ◽  
Vol 19 (4) ◽  
pp. 223-228 ◽  
Author(s):  
Shirley Palisoc ◽  
Michelle Natividad ◽  
Diana Mae Mae Calde ◽  
Elias Rafael Rosopa
Keyword(s):  
Glassy Carbon ◽  
Anodic Stripping Voltammetry ◽  
High Surface ◽  
Simultaneous Detection ◽  
Volume Ratio ◽  
Modified Electrodes ◽  
Carbon Electrodes ◽  
Peak Current ◽  
Glassy Carbon Electrodes ◽  
Lead And Cadmium

Graphene/[Ru(NH3)6]3+/nafion modified glassy carbon electrodes were fabricated using the drop coating technique. The fab-ricated electrodes were characterized using scanning electron microscopy (SEM) and cyclic voltammetry (CV). Simultaneous detection of lead (Pb2+) and cadmium (Cd2+) was done via anodic stripping voltammetry (ASV). The effects of varying the amounts of graphene and [Ru(NH3)6]3+ on the transport and sensing properties of the modified electrodes were determined. SEM results showed that the deposited films were smooth and uniform. CV results showed that the peak currents increase monotonically with the amounts of graphene and [Ru(NH3)6]3+. ASV results showed that modification of the GCE with graphene, [Ru(NH3)6]3+ and Nafion greatly enhanced the electrode’s sensitivity in detecting Pb2+ and Cd2+. This can be attributed to the high surface area-to-volume ratio of graphene, the mediation of elec-tron transfer by [Ru(NH3)6]3+ and the antifouling and cationic exchange capabilities of Nafion. The highest peak current for both Pb2+ and Cd2+ were obtained from the electrode modified with 1.5 mg [Ru(NH3)6]3+ and 3.0 mg graphene. A linear relationship between the peak current and metal concentration was obtained in the range of 1.4 ppb to 20 ppb for both Pb2+ and Cd2+ with a detection limit of 1.4 ppb. The modified electrodes were successful in detecting Cd2+ in real water samples. ASV results were verified using atomic absorption spec-troscopy.

scholarly journals Cyclic voltammetric study of the influence of porosity on electrochemical response of nickel-alumina modified glassy carbon electrode

2018 ◽  
Vol 50 (3) ◽  
pp. 313-321
Author(s):  
Ana Ivanovic-Sasic ◽  
Tatjana Novakovic ◽  
Zorica Mojovic ◽  
Zeljko Cupic ◽  
Dusan Jovanovic
Keyword(s):  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Modified Electrodes ◽  
Textural Properties ◽  
Nitrogen Adsorption ◽  
Carbon Electrode ◽  
Modified Glassy Carbon Electrode ◽  
Cyclic Voltammetric ◽  
Cyclic Voltammetric Study ◽  
Adsorption Desorption

Pure and nickel-modified alumina powders with different porosity were synthesized and applied on the glassy carbon electrode by means of Nafion polymer. The data obtained from the nitrogen adsorption-desorption isotherm confirmed that the pore structures in these materials are complex and tend to be made up of interconnected networks of pores of different size and shape. The addition of Ni2+ ions caused the changes in the textural properties of the samples. The influence of porosity on the electrochemical behavior of modified electrodes in quasi-reversible process was tested by cyclic voltammetry. Numerical correlations between electrochemical responses of GCE modified with alumina samples and textural properties have been established.

A simple and sensitive electrochemical detection of furazolidone based on an Au nanoparticle functionalized graphene modified electrode

2017 ◽  
Vol 9 (30) ◽  
pp. 4341-4348 ◽  
Author(s):  
Bao-Shan He ◽  
Geng-An Du
Keyword(s):  
Glassy Carbon Electrode ◽  
Modified Electrode ◽  
Electrochemical Detection ◽  
Glassy Carbon ◽  
Electrochemical Behavior ◽  
Au Nanoparticles ◽  
Au Nanoparticle ◽  
Carbon Electrode ◽  
Functionalized Graphene

A new sensor using a glassy carbon electrode modified with graphene and Au nanoparticles (Gr/Au/GCE) was designed to investigate the electrochemical behavior of furazolidone (FZD).

Preparation of Pt Colloids via a Wet-Chemical Method for Methanol Sensor

2011 ◽  
Vol 295-297 ◽  
pp. 527-530
Author(s):  
Hong Cheng Pan ◽  
Jiang Tao Liu ◽  
Jin Ming Liang ◽  
Dun Nan Li ◽  
Jian Ping Li ◽  
...  
Keyword(s):  
Modified Electrode ◽  
Glassy Carbon ◽  
Electrochemical Behavior ◽  
Chemical Method ◽  
Carbon Electrode ◽  
Wet Chemical Method ◽  
Oxidation Current ◽  
Methanol Sensor ◽  
Wet Chemical

Pt colloids were synthesized by a wet-chemical method. The Pt colloids were modified on the glassy carbon electrode (GCE). The electrochemical behavior and electrocatalyst for methanol of the colloidal Pt-modified electrode in H2SO4medium were investigated. The results show that the as-prepared Pt colloids are good electrocatalysts for methanol oxidation and the oxidation current increases with methanol concentration in the range of 0.002 to 0.5 M. The colloidal Pt-modified electrode is simple, easy-to-use and reusable, showing promising applications in the electrocatalyst and determination of methanol.

scholarly journals Nafion-coated cadmium pentacyanonitrosylferrate-modified glassy carbon electrode for detection of dopamine in biological samples

Bioimpacts ◽  
2017 ◽  
Vol 8 (4) ◽  
pp. 263-270
Author(s):  
Mohammad Johari-Ahar ◽  
Jaleh Barar ◽  
Pari Karami ◽  
Davoud Asgari ◽  
Soodabeh Davaran ◽  
...  
Keyword(s):  
Modified Electrode ◽  
Glassy Carbon ◽  
Biological Samples ◽  
Limit Of Detection ◽  
Biological Fluids ◽  
Modified Electrodes ◽  
Serum Samples ◽  
Selective Determination ◽  
Sensitivity And Selectivity

Introduction: Dopamine is one of the key neurotransmitters (NTs) in nature, which plays a crucial role in the mammalian central nervous system (CNS). Its selective determination in the biological fluids is an essential need in the field of biomedicine studies. Methods: In this work, an amperometric sensor was developed using Nafion-coated cadmium pentacyanonitrosylferrate (CdPCNF) modified glassy carbon (GC) electrode (Nafion|CdPCNF|GC electrode) as an electrocatalyst to detect dopamine (DA) in human serum samples. To develop this sensor, the surface of bare GC electrode was coated with the film of CdPCNF through an electropolymerization method and then the modified electrode was coated with Nafion to minimize interferences, especially those arising from the presence of anionic compounds. The electrocatalytic behavior of the modified electrodes was studied using the cyclic voltammetry and amperometry, and then the ability of the sensor for the determination of DA in synthetic and biological samples was investigated. Results: The modified electrode was showed a significant electrocatalytic activity for the oxidation of DA at pH 7.4. The limit of detection (LOD) was 0.7 µM and also no interference effects arose from ascorbic acid (AA), uric acid (UA) or the other biological NTs was observed in the DA detection using the modified Nafion|CdPCNF|GC electrode. Conclusion: In comparison with the bare electrode, the Nafion|CdPCNF|GC electrode could determine DA in the biological samples with adequate sensitivity and selectivity. Therefore, we propose that the modified electrode is utilizable as an amperometric DA sensor for the biological sample analysis.

Study on Electrochemical Behavior of Ortho-Aminophenol on Nano-Gold/Carbon Nanotubes Composite Modified Electrode

2013 ◽  
Vol 16 (2) ◽  
pp. 073-077
Author(s):  
Yingliang Wei ◽  
Anting Wang ◽  
Shengbin Wu
Keyword(s):  
Modified Electrode ◽  
Electrochemical Behavior ◽  
Linear Sweep Voltammetry ◽  
Scanning Speed ◽  
Nano Particles ◽  
Oxidation Peak ◽  
Linear Calibration ◽  
Buffer Solution ◽  
Peak Current ◽  
Nano Gold

The aim of this work was to construct a novel modified electrode based on Au nano-particles and carbon nanotube for studying the electrochemical behavior of ortho-aminophenol (OAP). A sensitive oxidation peak of OAP at the potential of 0.352V was observed in HAc-NaAc-PHP buffer solution. The effect factors of the electrochemical response of OAP were optimized by linear sweep voltammetry (LSV). Under the optimum conditions, a linear calibration curve of the peak current of OAP and concentration was obtained in the range of 4.0×10-7~2.0×10-4 mol/L. The oxidation peak current increases direct proportionally with the square root of scanning speed, which indicates that the electrochemical oxidation process of OAP on this modified electrode is diffusion-controlled process. The diffusion coefficient (D) could be estimated and the result was 5.42×10-7 cm2·s-1 by employing chronocoulometry. The charge transfer rate constant (ks) was also discussed and the result was 7.85×10-4 cm·s-1. Concurrently, based on the experiment results, the electrode reaction process of OAP with one electron and one proton was proposed.

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