scholarly journals Electroanalytical determination of gallic acid in red and white wine samples using cobalt oxide nanoparticles-modified carbon-paste electrodes

2021 ◽  
Vol 160 ◽  
pp. 105668
Author(s):  
Chrys.O. Chikere ◽  
Emma Hobben ◽  
Nadimul Haque Faisal ◽  
Paul Kong-Thoo-Lin ◽  
Carlos Fernandez
2019 ◽  
Vol 9 (1) ◽  
pp. 110-121 ◽  
Author(s):  
Nada Farouk Atta ◽  
Ahmed Galal ◽  
Ekram Hamdy El-Ads ◽  
Samar Hamed Hassan

Purpose: Drug-abuse, namely morphine (MO) affects the metabolism of neurotransmitterssuch as dopamine (DA). Therefore, it is crucial to devise a sensitive sensing technique tosimultaneously determine both compounds in real samples.Methods: The fabrication of the sensor is based on in situ modification of a carbon paste (CP)electrode with cobalt oxide nanoparticles, graphene, and ionic liquid crystal in presence ofsodium dodecyl sulfate; CoGILCCP-SDS. The modified sensor is characterized using scanningelectron microscopy, electrochemical impedance spectroscopy and voltammetry measurements.Results: Electron transfer kinetics and analytical performance of the proposed sensor wereenhanced due to the synergistic role of all the modifiers. The simultaneous determination of MOand DA achieved low detection limits of 0.54 nmol L−1 and 0.25 nmol L−1, respectively. Besides,a carbon-based electrochemical sensor is fabricated for the nano-molar determination of MOin real samples and formulations. The sensor showed fouling resistance and anti-interferenceability in presence of other species in human fluids. The real sample analysis of MO wassuccessfully achieved with good recovery results in urine samples and pharmaceutical tablets.Linear dynamic range, sensitivity, detection limit and quantification limit of MO in urine were5 nmol L−1 to 0.6 μmol L−1, 6.19 μA/μmol L-1, 0.484 nmol L−1 and 1.61 nmol L−1, respectively.Conclusion: This sensor has great ability to be extended for electrochemical applications inassaying of many drugs.


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.


2017 ◽  
Vol 41 (24) ◽  
pp. 15612-15624 ◽  
Author(s):  
Gehad G. Mohamed ◽  
Eman Y. Z. Frag ◽  
M. A. Zayed ◽  
M. M. Omar ◽  
Sally E. A. Elashery

Newly developed modified and in situ modified carbon paste sensors were developed for the determination of chlorpromazine hydrochloride (CPZHC) in pharmaceutical formulations and biological fluids (urine and serum).


2011 ◽  
Vol 56 (19) ◽  
pp. 6673-6677 ◽  
Author(s):  
Eva Svobodova-Tesarova ◽  
Lucie Baldrianova ◽  
Matej Stoces ◽  
Ivan Svancara ◽  
Karel Vytras ◽  
...  

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