scholarly journals Interaction between Amorphous Zirconia Nanoparticles and Graphite: Electrochemical Applications for Gallic Acid Sensing Using Carbon Paste Electrodes in Wine

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 537 ◽  
Author(s):  
Chrys. O. Chikere ◽  
Nadimul Haque Faisal ◽  
Paul Kong-Thoo-Lin ◽  
Carlos Fernandez

Amorphous zirconium oxide nanoparticles (ZrO2) have been used for the first time, to modify carbon paste electrode (CPE) and used as a sensor for the electrochemical determination of gallic acid (GA). The voltammetric results of the ZrO2 nanoparticles-modified CPE showed efficient electrochemical oxidation of gallic acid, with a significantly enhanced peak current from 261 µA ± 3 to about 451 µA ± 1. The modified surface of the electrode and the synthesised zirconia nanoparticles were characterised by scanning electrode microscopy (SEM), Energy-dispersive x-ray spectroscopy (EDXA), X-ray powdered diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). Meanwhile, the electrochemical behaviour of GA on the surface of the modified electrode was studied using differential pulse voltammetry (DPV), showing a sensitivity of the electrode for GA determination, within a concentration range of 1 × 10−6 mol L−1 to 1 × 10−3 mol L−1 with a correlation coefficient of R2 of 0.9945 and a limit of detection of 1.24 × 10−7 mol L−1 (S/N = 3). The proposed ZrO2 nanoparticles modified CPE was successfully used for the determination of GA in red and white wine, with concentrations of 0.103 mmol L−1 and 0.049 mmol L−1 respectively.

Author(s):  
Ashraf Mahmoud ◽  
Mater Mahnashi ◽  
Samer Abu-Alrub ◽  
Saad Kahatani ◽  
Mohamed El-Wekil

Abstract An innovative and reliable electrochemical sensor was proposed for simple, sensitive and selective determination of F- ions. The sensor is based on the fabrication of porous and electroactive Fe-based metal organic frameworks [MIL-101(Fe)]. It was blended with graphite powder and liquid paraffin oil to from carbon paste electrode (CPE). The MIL-101(Fe)@CPE was characterized using different techniques such as scanning electron microscope, powder X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, energy dispersive X-ray, cyclic voltammetry, electrochemical impedance spectroscopy, differential pulse voltammetry. The MIL-101(Fe)@CPE exhibited two redox peaks (anodic and cathodic) corresponding to Fe3+ and Fe2+, respectively. The determination of F- ions based on the formation of a stable fluoroferric complex with Fe3+/ Fe2+, decreasing the currents of redox species. It was found that the anodic peak current (Ipa) is linearly proportional to the concentration of F- in the range of 0.67-130 µM with a limit of detection (S/N=3) of 0.201 µM. The electrode exhibited good selectivity towards F- detection with no significant interferences from common anions. The as-fabricated sensor was applied for the determination of F- in environmental water samples with recoveries % and RSDs % in the range of 98.1-102.4 % and 2.4-3.7 %, respectively.


2021 ◽  
Vol 4 (01) ◽  
pp. 16-25
Author(s):  
Hamideh Asadollahzadeh

Zinc oxide (ZnO) nanoparticles with an average size of 60 nm have been successfully prepared by microwave irradiation. Carbon paste electrode (CPE) was modified with ZnO nanoparticles and used for the electrochemical oxidation of chlorpheniramine maleate (CPM). Cyclic voltammetry (CV) study of the modified electrode indicated that the oxidation potential shifted towards a lower potential by approximately 106 mV and the peak current was enhanced by 2 fold in comparison to the bare CPE (ZnO/CPE-CV). The electrochemical behaviour was further described by characterization studies of scan rate, pH and concentration of CPM. Under the optimal conditions, the peak current was proportional to CPM concentration in the range of 8.0 ×10-7 to 1.0 × 10-3 mol L-1 with a detection limit of 5.0 × 10-7 mol L-1 by differential pulse voltammetry (DPV). The peak current of CPM is linear in the concentration range of 0.8 - 1000 µM (R2=0.998). The ZnO/CPE has good reproducibility and high stability for the determination of CPM using this electrode. The proposed method was successfully applied to the determination of CPM in pharmaceutical samples. In addition, the important analytical parameters were compared with other methods which show that ZnO/CPE-CV procedure is comparable to recently reported methods.


2020 ◽  
Author(s):  
Miao Liu ◽  
Mingxuan Jia ◽  
Dong Hui Li

Abstract An innovative method for the determination of isoniazid tablets is studied through electrochemical method for the modification of glassy carbon electrode (GCE). Polyoxomolybdate, with stable structures, has not been widely used for the determination of substance. In this study, the mentioned polyoxomolybdate was characterized by Fourier transform infrared spectroscopy (FT-IR), UV-vis, X-ray diffraction (XRD), Atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS), and used to modify the glassy carbon electrode. The electrochemical performance of the polyoxomolybdate@GCE was investigated with cyclic voltammetry (CV) and differential pulse voltammetry (DPV), compared with the unmodified electrode, the proposed polyoxomolybdate modified electrode exhibited strong electro-catalytic activities towards isoniazid (INH). Under the optimized conditions, there was linear relationships between the DPV peak currents and the concentrations in the range of 1 × 10 -7 g/L to 3 × 10 -7 g/L for INH (R 2 = 0.9979), with the limit of detection (LOD) of 0.024 μg/L (based on S/N = 3). The modified electrode has proper reproducibility (RSD < 5%), stability, response time (< 3 min) and lifetime (up to 6 days).


2009 ◽  
Vol 74 (10) ◽  
pp. 1503-1515 ◽  
Author(s):  
Zuzana Jemelková ◽  
Jiří Zima ◽  
Jiří Barek

Direct current voltammetric (DCV) and differential pulse voltammetric (DPV) determination of antineoplastic agent doxorubicin (DOX) at a carbon paste electrode (CPE) was developed. Britton–Robinson buffer (pH 7.0) was used as a supporting electrolyte. The limits of detection are 8 × 10–7 mol l–1 (DCV) and 6 × 10–8 mol l–1 (DPV). The accumulation of DOX at the electrode surface was used to decrease the limits of detection down to 2.2 × 10–7 mol l–1 for adsorptive stripping DC voltammetry (DCAdSV) and 2.8 × 10–9 mol l–1 for adsorptive stripping differential pulse voltammetry (DPAdSV) at CPE. The results of the voltammetric methods were utilized for the development of a new determination of doxorubicin using HPLC with amperometric detection on CPE based on spherical microparticles of glassy carbon in a wall-jet configuration. A column with chemically bonded C18 stationary phase and a mobile phase containing 0.01 M phosphate buffer (pH 5.0)–methanol 25:75 (v/v) were used. The limit of detection is 4 × 10–7 mol l–1 (HPLC with electrochemical detection (ED)).


2016 ◽  
Vol 11 (2) ◽  
pp. 175
Author(s):  
Irdhawati Irdhawati ◽  
Manuntun Manurung ◽  
Anisha Maulinasari

In this research, the modified carbon paste electrode with crown ether (dibenzo-18-crown-6) has been prepared, for determination of ascorbic acid. Some of parameters observed were optimization of crown ether composition in carbon paste, pH of solution, linear concentration range, limit of detection, reproducibility, and recovery. The optimum performance of the prepared electrode was applied for determination of commercialsampleswhich contain of ascorbic acid. The result of this research showsthat the optimum composition of crown ether in carbon paste is 0.6 % at pH 4. Linear range of concentration obtained is from 2 - 200 μM. The detection limit and percentage of recovery are 1.243 μM and 101.31 %, respectively. The modified electrode has HorRat value less than 2, it indicates a good reproducibility. Analysis of 4 commercial samples which contain of ascorbic acid were in agreement with the content listed in the label with the suitability of 94 - 100 %.


2016 ◽  
Vol 11 (2) ◽  
pp. 175
Author(s):  
Irdhawati Irdhawati ◽  
Manuntun Manurung ◽  
Anisha Maulinasari

In this research, the modified carbon paste electrode with crown ether (dibenzo-18-crown-6) has been prepared, for determination of ascorbic acid. Some of parameters observed were optimization of crown ether composition in carbon paste, pH of solution, linear concentration range, limit of detection, reproducibility, and recovery. The optimum performance of the prepared electrode was applied for determination of commercialsampleswhich contain of ascorbic acid. The result of this research showsthat the optimum composition of crown ether in carbon paste is 0.6 % at pH 4. Linear range of concentration obtained is from 2 - 200 μM. The detection limit and percentage of recovery are 1.243 μM and 101.31 %, respectively. The modified electrode has HorRat value less than 2, it indicates a good reproducibility. Analysis of 4 commercial samples which contain of ascorbic acid were in agreement with the content listed in the label with the suitability of 94 - 100 %.


2015 ◽  
Vol 22 (3) ◽  
pp. 451-458
Author(s):  
Vít Novotný ◽  
Jiří Barek

Abstract A method for the determination of aclonifen at a carbon paste electrode modified with tricresyl phosphate has been developed. The optimum electrochemical regime proved to be differential pulse voltammetry (DPV) in the negative potential range from −200 to −1600 mV. The optimum pH for the determination proved to be pH = 8. The calibration dependence is linear and the limit of detection achieved for the method was 2·10−6 mol/dm3. The method is fast, reliable and it is suitable for the detection of aclonifen in the concentration range from 2·10−6 to 1·10−4 mol/dm3.


2005 ◽  
Vol 70 (3) ◽  
pp. 292-304 ◽  
Author(s):  
Natalija German ◽  
Saulius Armalis ◽  
Jiří Zima ◽  
Jiří Barek

Square wave voltammetry and differential pulse voltammetry have been used for the determination of 2-acetamidofluorene and fluoren-9-ol using carbon paste electrodes, following the study of the influence of the carbon paste composition on the voltammetric signals of the analytes. The methods are based on the oxidation of the above compounds and they include adsorptive accumulation of the analyte on the surface of the working electrode. The limit of detection was 1 μmol l-1for fluoren-9-ol in a medium of 0.1 M H2SO4, and 40 nmol l-1for 2-acetamidofluorene in Britton-Robinson buffer (pH 7).


2018 ◽  
Vol 11 (4) ◽  
pp. 99
Author(s):  
Luane Ferreira Garcia ◽  
Carlos Eduardo Peixoto da Cunha ◽  
Emily Kussmaul Gonçalves Moreno ◽  
Douglas Vieira Thomaz ◽  
Germán Sanz Lobón ◽  
...  

Methyldopa is a catecholamine widely used in the treatment of mild to moderate hypertension whose determination in pharmaceutical formulae is of upmost importance for dose precision. Henceforth, a low-cost carbon paste electrode (CPE) consisting of graphite powder obtained from a crushed pencil stick was herein modified with nanostructured TiO2 (TiO2@CPE) aiming for the detection of methyldopa in pharmaceutical samples. The TiO2-modified graphite powder was characterized by scanning electron microscopy and X-ray diffraction, which demonstrated the oxide nanostructured morphology. Results evidenced that sensitivity was nonetheless increased due to electro-catalytic effects promoted by metal modification, and linear response obtained by differential pulse voltammetry for the determination of methyldopa (pH = 5.0) was between 10–180 μmol/L (Limit of Detection = 1 μmol/L) with the TiO2@CPE sensor. Furthermore, the constructed sensor was successfully applied in the detection of methyldopa in pharmaceutical formulations and excipients promoted no interference, that indicates that the sensor herein developed is a cheap, reliable, and useful strategy to detect methyldopa in pharmaceutical samples, and may also be applicable in determinations of similar compounds.


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