scholarly journals Electrochemical Glucose Oxidation Using Glassy Carbon Electrodes Modified with Au-Ag Nanoparticles: Influence of Ag Content

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Nancy Gabriela García-Morales ◽  
Luis Alfonso García-Cerda ◽  
Bertha Alicia Puente-Urbina ◽  
Leonor María Blanco-Jerez ◽  
René Antaño-López ◽  
...  
Keyword(s):  
Glassy Carbon ◽  
Electrode Surface ◽  
Glucose Oxidation ◽  
Modified Electrodes ◽  
Alkaline Media ◽  
Carbon Electrodes ◽  
X Ray Diffraction ◽  
Simple Method ◽  
Glassy Carbon Electrodes ◽  
Transmission Electron

This paper describes the application of glassy carbon modified electrodes bearing Aux-Agynanoparticles to catalyze the electrochemical oxidation of glucose. In particular, the paper shows the influence of the Ag content on this oxidation process. A simple method was applied to prepare the nanoparticles, which were characterized by transmission electron microscopy, Ultraviolet-Visible spectroscopy, X-ray diffraction spectroscopy, and cyclic voltammetry. These nanoparticles were used to modify glassy carbon electrodes. The effectiveness of these electrodes for electrochemical glucose oxidation was evaluated. The modified glassy carbon electrodes are highly sensitive to glucose oxidation in alkaline media, which could be attributed to the presence of Aux-Agynanoparticles on the electrode surface. The voltammetric results suggest that the glucose oxidation speed is controlled by the glucose diffusion to the electrode surface. These results also show that the catalytic activity of the electrodes depends on the Ag content of the nanoparticles. Best results were obtained for the Au80-Ag20nanoparticles modified electrode. This electrode could be used for Gluconic acid (GA) production.

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.

Enhanced photostability of cuprous oxide by lignin films on glassy carbon electrodes in the transformation of carbon dioxide

2018 ◽  
Vol 20 (10) ◽  
pp. 2356-2364 ◽  
Author(s):  
Esteban Landaeta ◽  
Zachary D. Schultz ◽  
Ana Burgos ◽  
Ricardo Schrebler ◽  
Mauricio Isaacs
Keyword(s):  
Carbon Dioxide ◽  
Glassy Carbon ◽  
Cuprous Oxide ◽  
Modified Electrodes ◽  
Carbon Electrodes ◽  
Glassy Carbon Electrodes ◽  
Residual Product ◽  
Enhanced Photostability

Lignin is a residual product can be reused for stabilize Cu2O on modified electrodes in CO2 reduction.

Effects of the number of ring substituents of cobalt carboxyphthalocyanines on the electrocatalytic detection of nitrite, cysteine and melatonin

2009 ◽  
Vol 13 (08n09) ◽  
pp. 986-997 ◽  
Author(s):  
Fungisai Matemadombo ◽  
Nthapo Sehlotho ◽  
Tebello Nyokong
Keyword(s):  
Ascorbic Acid ◽  
Glassy Carbon ◽  
Detection Limits ◽  
Modified Electrodes ◽  
Carbon Electrodes ◽  
Cobalt Phthalocyanine ◽  
Carbon Electrode ◽  
Good Separation ◽  
Glassy Carbon Electrodes ◽  
A Value

Cobalt phthalocyanine (CoPc), cobalt tetracarboxy phthalocyanine (CoTCPc) and cobalt octacarboxy phthalocyanine (CoOCPc), adsorbed onto glassy carbon electrodes, have been used for the electrocatalytic detection of nitrite, L-cysteine and melatonin. The modified electrodes electrocatalytically detected nitrite around 800 mV vs. Ag|AgCl , a value less positive compared to that of an unmodified glassy carbon electrode (at 950 mV vs. Ag|AgCl ) and also gave detection limits in the 10-7 M range for nitrite detection. L-cysteine was detected by the modified electrodes at potentials between 0.50 to 0.65 V vs. Ag|AgCl , with L-cysteine detection limits also in the 10-7 M range. The detection limits for melatonin ranged from 10-7 to 10-6 M. CoPc-modified electrodes displayed good separation of interferents (tryptophan and ascorbic acid) in the presence of melatonin. Analyses of commercial melatonin tablets using modified electrodes gave excellent agreement with manufacturer's value for all modified electrodes of this work.

scholarly journals Glassy Carbon Electrode Modified by Molybdenum to Detection Hydrochlorothiazide

2020 ◽  
Author(s):  
Ahmad Khalaf Alkhawaldeh ◽  
Rawia Alkhawaldeh
Keyword(s):  
Glassy Carbon ◽  
Correlation Coefficients ◽  
Modified Electrodes ◽  
Pharmaceutical Formulations ◽  
Carbon Electrodes ◽  
Low Molecular Weight ◽  
Molybdenum Oxides ◽  
Statistical Parameters ◽  
Glassy Carbon Electrodes

Molybdenum oxides is well-known electro-catalysts in fuel cells systems, they are usually used as anodic materials for the oxidation of low molecular weight alcohols. The utilization of Mo as catalysts in the pharmaceutical analysis is not common yet. In this study, bare glassy carbon electrodes were modified by the oxides by means of electrochemical deposition and the modified electrodes were used as catalysts for the electrochemical oxidation of hydrochlorothiazide (HCT). Well-resolved anodic peaks were reported for the analyzed pharmaceuticals when the Mo/GCE was utilized for the analysis of HCT. Analytical performance of the modified electrodes was evaluated based on the following statistical parameters; linearity ranges, correlation coefficients, limits of detection and quantitation, and recovery values. The prepared electrodes were used for the determination of the active ingredients in their pharmaceutical formulations and the reported activity was correlated to influence of the utilized pH on both structures of the used electrodes and the detected analytes.

Hydrazine electrooxidation mediated by transition metal octaethylporphyrin-modified electrodes

2016 ◽  
Vol 40 (3) ◽  
pp. 2806-2813 ◽  
Author(s):  
Camila Canales ◽  
Leyla Gidi ◽  
Roxana Arce ◽  
Galo Ramírez
Keyword(s):  
Transition Metal ◽  
Glassy Carbon ◽  
Modified Electrodes ◽  
Carbon Electrodes ◽  
Glassy Carbon Electrodes ◽  
Hydrazine Oxidation ◽  
Hydrazine Electrooxidation

Glassy carbon electrodes modified with cobalt(ii) octaethylporphyrin capable of catalyzing hydrazine oxidation at low overpotentials.

Covalent attachment of diphosphine ligands to glassy carbon electrodes via Cu-catalyzed alkyne-azide cycloaddition. Metallation with Ni(ii)

2015 ◽  
Vol 44 (27) ◽  
pp. 12225-12233 ◽  
Author(s):  
Atanu K. Das ◽  
Mark H. Engelhard ◽  
Sheri Lense ◽  
John A. S. Roberts ◽  
R. Morris Bullock
Keyword(s):  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Electrode Surface ◽  
Click Reaction ◽  
Covalent Attachment ◽  
Carbon Electrodes ◽  
Diphosphine Ligands ◽  
Carbon Electrode ◽  
Glassy Carbon Electrodes

Covalent tethering of a P2N2 ligand to a planar, azide-terminated glassy carbon electrode surface was accomplished using a CuI-catalyzed “click” reaction, followed by metallation with NiII.

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