scholarly journals Voltammetric determination of dopamine in the presence of uric acid using a 2-hydroxy-1-(1-hydroxynaphthyl-2-azo)- naphthalin-4-sulfonic acid modified glassy carbon electrode

2010 ◽  
Vol 75 (12) ◽  
pp. 1685-1699 ◽  
Author(s):  
Asghar Ensafi ◽  
Samira Dadkhah-Tehrani ◽  
B. Rezaei
Keyword(s):  
Uric Acid ◽  
Glassy Carbon Electrode ◽  
Modified Electrode ◽  
Glassy Carbon ◽  
Sulfonic Acid ◽  
Reaction Rate Constant ◽  
Carbon Electrode ◽  
Electrochemical Behaviors ◽  
Peak Separation

A polymerized film of 2-hydroxy-1-(1-hydroxynaphthyl-2-azo)- naphthalin-4-sulfonic acid (HHNANSA) was prepared at the surface of a glassy carbon electrode by electropolymerization. The modified electrode was used for the simultaneous determination of dopamine (DA) and uric acid (UA). The electrochemical behaviors of the compounds at the surface of the modified electrode were studied using cyclic voltammetry, chronoamperometry, and square wave voltammetry (SWV). The experimental results indicated that the modified electrode exhibited an efficient electrocatalytic activity towards the oxidation of DA and UA, with a peak separation of about 140 mV at pH 5.0. Using chronoamperometry, the catalytic reaction rate constant was measured and found to equal to 1.23 ? 104 mol-1 L s-1. At pH 5.0, the catalytic peak currents linearly depended on the DA and/or UA concentrations in the range of 1.0 - 300 ?mol L-1 DA (two linear segments with different slopes) and 6.7 - 20 ?mol L-1 UA, using SWV. The detection limits for DA and UA were 0.25 ?mol L-1 and 1.17 ?mol L-1, respectively. The RSD % for 40.0 and 140.0 ?mol L-1 DA were 1.9 % and 2.2 %, respectively, whereas for 10.0 and 20.0 ?mol L-1 UA, they were 1.8 % and 1.2 %, respectively. The modified electrode showed good sensitivity, selectivity, and stability. It was successfully applied for the determination of DA and UA in real samples, such as drugs and urine.

A Novel Silver-Doped Poly(p-aminobenzene sulfonic acid) Modified Glassy Carbon Electrode for Analysis of H2O2

2012 ◽  
Vol 600 ◽  
pp. 133-136
Author(s):  
De Ling Chi ◽  
Kai Zhao ◽  
Zheng Xiao Liu ◽  
Fei Fei Zhang ◽  
Zong Hua Wang
Keyword(s):  
Glassy Carbon Electrode ◽  
Modified Electrode ◽  
Glassy Carbon ◽  
Sulfonic Acid ◽  
Carbon Electrode ◽  
Modified Glassy Carbon Electrode ◽  
Electrochemical Behaviors

A novel silver-doped poly (p-aminobenzene sulfonic acid) modified electrode was fabricated, of which the electrochemical behaviors were studied with H2O2as a probe. In pH 7.0 PBS, a sensitive reductive peak of H2O2was observed. The modified electrode is of potential in practice for analysis of H2O2in samples such as milk.

scholarly journals Poly(4-amino-3-hydroxynaphthalene-1-sulfonic acid) modified glassy carbon electrode for square wave voltammetric determination of amoxicillin in four tablet brands

BMC Chemistry ◽  
2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Adane Kassa ◽  
Meareg Amare
Keyword(s):  
Glassy Carbon Electrode ◽  
Modified Electrode ◽  
Glassy Carbon ◽  
Sulfonic Acid ◽  
Current Response ◽  
Carbon Electrode ◽  
Modified Glassy Carbon Electrode ◽  
Serum Samples ◽  
Square Wave

Abstract Background Amoxicillin (AMX), which is one of the β-lactam antibiotics used in the treatment of bacterial infections, is known to have a serious mechanism of resistance necessitating continuous monitoring of its level in pharmaceutical and serum samples. Results In this study, we presented selective, accurate, and precise square wave voltammetric method based on poly(4-amino-3-hydroxynaphthalene-1-sulfonic acid) modified glassy carbon electrode (poly(AHNSA/GCE)) for determination of amoxicillin in four selected tablet brands. Appearance of a peak in the oxidative scan direction without a peak in the reductive direction of cyclic voltammograms of both bare GCE and poly(AHNSA/GCE) with four folds current and much reduced potential on the modified electrode showed catalytic property of the modifier towards oxidation of AMX. While cyclic voltammetric studies of effect of scan rate showed predominantly diffusion controlled oxidation of AMX with one electron participation, effect of pH revealed participation of protons and electrons in a 1:1 ratio. The square wave voltammetric peak current response of the modified electrode for AMX showed linear dependence on the concentration of the spiked standard AMX in the range 10–150 µmol L−1 with 9.9 nmol L−1 LOD. The AMX content of the studied tablet brands were found in the range 97.84–100.78% of the labeled value. Spike recovery results of 99.6–100.5%, and interference recovery results of 95.4–100.8% AMX in the presence of 50–200% of ampicillin and cloxicillin validated the applicability of the method for determination of amoxicillin in tablet formulation. Conclusion In contrast to the previously reported works on determination of amoxicillin, the present method showed an excellent performance making it a potential method for determination of amoxicillin in real samples including serum samples.

Electrocatalytic Property Toward Dopamine and Uric Acid of the Nanoparticles TiO2 Modified Electrode

2013 ◽  
Vol 785-786 ◽  
pp. 508-511
Author(s):  
Ying Zhang ◽  
Guo Bao Li ◽  
Qiu Xia Yang
Keyword(s):  
Uric Acid ◽  
Linear Relationship ◽  
Glassy Carbon Electrode ◽  
Modified Electrode ◽  
Glassy Carbon ◽  
Differential Pulse ◽  
Carbon Electrode ◽  
Oxidation Peak ◽  
Good Electrocatalytic Activity

The titanium sol was prepared by depositing the organic titanium on glassy carbon electrode surface. Electrophoresis time and the applied voltage as well can markedly influence the electrochemical behavior of the nanoTiO2film. In contrast with bare glassy carbon electrode, the nanoTiO2film on glassy carbon electrode had a good electrocatalytic activity to dopamine (DA) and uric acid (UA) in PBS solution. The result showed that there was a linear relationship between the oxidation peak currents and the concentration of DA from 8.0×10-6to 4.0×10-4mol·L-1by differential pulse voltammetry (DPV) and there was a linear relationship between the oxidation peak currents and the concentration of UA from 8×10-6to 1.0×10-3mol·L-1. This modified electrode was quite effective to detect DA and UA in simultaneous determination of these species in a mixture.

Simultaneous Determination of Hydroquinone and Catechol at Poly-Histidine Film Modified Glassy Carbon Electrode

2013 ◽  
Vol 781-784 ◽  
pp. 89-92
Author(s):  
Qiu Xia Yang ◽  
Wei Ping Sui ◽  
Da Wei Fan ◽  
Guo Bao Li
Keyword(s):  
Simultaneous Determination ◽  
Glassy Carbon Electrode ◽  
Modified Electrode ◽  
Glassy Carbon ◽  
Differential Pulse ◽  
Electrode Reaction ◽  
Carbon Electrode ◽  
Selective Determination ◽  
Peak Separation

The poly-histidine (poly-HTD) film was prepared at glassy carbon electrode by electropolymerization, and its electrochemical behavior was investigated by cyclic voltammetry. Results show that the behavior of this poly-HTD film is in good agreement with quasi-reversible process characteristic. At low scan rates, the electronic transfer process of electrode reaction is controlled by surface process. At this poly-HTD film modified electrode, an excellent electrocatalytic ability towards the redox of hydroquinone (HQ) and catechol (CC) with decrease of the overpotential and improvement of the redox peak currents was found. Differential pulse voltammetry was used for the simultaneous determination of HQ and CC in their mixture, and the peak-to-peak separation ΔEpfor HQ and CC was 110 mV. Therefore, this polymer modified electrode can be used for the simultaneously selective determination of HQ and CC without interference with each other.

scholarly journals Electrochemical Determination of Uric Acid in Urine by Using Zeolite Imidazolate Framework-11 Modified Electrode

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Tran Si Thanh ◽  
Phan Tu Qui ◽  
Nguyen Thi Thanh Tu ◽  
Tran Thanh Tam Toan ◽  
Tran Thi Bich Hoa ◽  
...  
Keyword(s):  
Uric Acid ◽  
Glassy Carbon Electrode ◽  
Modified Electrode ◽  
Glassy Carbon ◽  
Anodic Stripping Voltammetry ◽  
High Surface ◽  
Hydrothermal Process ◽  
Electrochemical Determination ◽  
Carbon Electrode

In the present article, the synthesis of zeolite imidazole framework-11 (ZIF-11) by ultrasonic-assisted hydrothermal process and its application as an electrode modifier for electrochemical determination of uric acid in urine are demonstrated. The obtained materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and nitrogen adsorption/desorption isotherms. It was found that the ZIF-11 with rhombic dodecahedron topology and high surface area (1066 m2.g-1) was synthesized in a certain temperature and found in around 25–40°C, and other crystalline phases of zinc benzimidazolate deferring from ZIF-11 phase were found in less 25°C or higher than 40°C. The ZIF-11 is stable in the pH range 6-10. The modification of glassy carbon electrode was performed with ZIF-67 using the drop-casting procedure. The present ZIF-11 modified electrode was employed to study the electrochemical behavior of uric acid (UA). UA oxidation is catalyzed by this electrode in aqueous buffer solution (pH 7) with a decrease of 70 mV in overpotential compared to glassy carbon electrode. With the differential pulse–anodic stripping voltammetry (DP-ASV) method, the oxidation current of UA versus its concentration shows good linearity in the range 20–540μM ( R = 0.998 ) with a detection limit of 0.48 μM ( S / N = 3 ). The obtained ZIF-11 modified electrode was applied in the detection of UA content in urine samples, and satisfied results were obtained.

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 Electrochemical Determination of Trace Pb (II) by The Modified Glassy Carbon Electrode Compositing MultiWalled Carbon Nanotubes-Nafion-Bi Film

2020 ◽  
pp. 1-12
Keyword(s):  
Carbon Nanotubes ◽  
Glassy Carbon Electrode ◽  
Modified Electrode ◽  
Glassy Carbon ◽  
Anodic Stripping Voltammetry ◽  
Electrochemical Sensing ◽  
Carbon Electrode ◽  
Bismuth Film ◽  
Modified Glassy Carbon Electrode

A modified glassy carbon electrode (GCE) compositing multi-walled carbon nanotubes (MWCNTs), Nafion and bismuth film was prepared and applied for the sensitive detection of trace Pb (II). MWCNTs were dispersed into ethanol by ultrasonication in the presence of Nafion and the nanotubes are coated onto the bare GCE. After that, an extra Nafion adhesion agent is added to the electrode. By the in situ plating, a bismuth film was fabricated on the MWCNTs-NA/GCE, making the desired electrode, MWCNTs-NA-Bi/GCE. The modified electrode was characterized by differential pulse anodic stripping voltammetry, scanning electron microscopy, and cyclic voltammetry. A deposition potential of –1.4 V (vs. Ag/AgCl) and a deposition time of 300 s were applied to the working electrode under stirred conditions after optimizing. Nanotubes and Nafion concentrations and pH were carefully optimized to determine trace lead ions by using the electrode as an electrochemical-sensing platform. Nafion effectively increased the stability and adhesivity of the composite film. The MWCNTs-NA-Bi film modified electrode can remarkably increase the anodic peak current of Pb2+. The sensitivity of MWCNTs-NA-Bi/GCE is 4.35 times higher than that of the bare GCE with bismuth film. The prepared electrode showed excellent stability and reproducibility and can be applied for determination of Pb2+ contained wastewater.

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