scholarly journals Evaluation Of Carbon Paste Electrode Modified With Heavy Metals For The Analysis Of Paracetamol By Voltammetry And Impedance Spectroscopy

2020 ◽  
Vol 15 (2) ◽  
pp. 93-99
Author(s):  
Hayat EL Ouafy ◽  
Tarik EL Ouafy ◽  
Mustapha Oubenali ◽  
Mohamed Mbarki ◽  
Malika Echajia
Keyword(s):  
Heavy Metals ◽  
Impedance Spectroscopy ◽  
Carbon Paste Electrode ◽  
Electrochemical Impedance ◽  
Charge Transfer Resistance ◽  
Carbon Paste ◽  
Transfer Resistance ◽  
Voltammetric Behavior ◽  
Paste Electrode ◽  
Weak Concentration

The present document reports on the electrocatalytic activity of heavy metals (Copper(II), Nickel(II), Manganese(II) and Lead(II)) modified carbon paste electrodes (HM/CPE) for the paracetamol (Pr) oxidation where its results are compared with carbon paste electrode. The voltammetric behavior of Pr is explored where a sensitive anodic peak has appeared at about 0.27 V (vs. Ag/AgCl/3 M KCl) in 0.1 M Na2SO4 (pH 12). This peak results from the irreversible oxidation of Pr at HM/CPE surface. The catalytic effect was evaluated using cyclic and square wave voltammetry. Electrochemical impedance spectroscopy also confirms our experimental results as the HM/CPE shows the least charge transfer resistance. Also, HM/ CPE can be utilized successfully to ameliorate the electroanalysis of Pr at very weak concentration with excellent sensitivity. The calibration curves were linear from 6.0 · 10-5 to 8.0 · 10-4 mol L-1. The detection limits were found approaching 10-9 mol L-1. Then, the proposed method was applied to detect Pr in river water samples with satisfactory results.

scholarly journals NaOH Pretreated Molybdate-Carbon Paste Electrode for the Determination of Phosphate in Seawater by Square Wave Voltammetry with Impedimetric Evaluation

2021 ◽  
Author(s):  
Mahmoud Fatehy Abdalqader Altahan ◽  
Eric Achterberg ◽  
Asmaa Galal ◽  
Magdi Abdel Azzem
Keyword(s):  
Cyclic Voltammetry ◽  
Carbon Paste Electrode ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Calibration Plot ◽  
Good Precision ◽  
Carbon Paste ◽  
Transfer Resistance ◽  
Paste Electrode

Abstract Here we describe a new electrochemical sensor for PO4 3− detection in seawater. In this work, we prepared a carbon paste electrode (CPE) modified with molybdate and pretreated in 0.1 M NaOH using cyclic voltammetry (CV). The modified CPE was employed for the determination of PO4 3− in artificial seawater (35 g/L NaCl) acidified with sulfuric acid to pH 0.8. An additional cleaning step (cyclic voltammetry (CV)) of 10 cycles in 0.1 M NaOH at −0.5 to 0.5 V was required between PO4 3− determinations to dissolve the phosphomolybdic complex formed on the surface of the working electrode. Electrochemical impedance spectroscopy (EIS) results confirmed that the molybdate-modified CPE (molybdate/CPE) exhibited a low charge-transfer resistance (Rct) toward PO4 3−, and showed an improved analytical performance for different concentrations of PO4 3−. A calibration plot in the range of 0.01–5 µM with a limit of detection (LOD) of 0.003 µM was obtained. The proposed electrode demonstrated good precision (4.3% and 5.8%) for concentrations of 5 and 0.2 µM, respectively. The proposed method was employed to analyze PO4 3− in seawater samples on a research cruise in the North Sea, with results in close agreement to those obtained using conventional colorimetric measuremen

scholarly journals Deciphering the Disaggregation Mechanism of Amyloid Beta Aggregate by 4-(2-Hydroxyethyl)-1-Piperazinepropanesulfonic Acid Using Electrochemical Impedance Spectroscopy

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 788
Author(s):  
Hien T. Ngoc Le ◽  
Sungbo Cho
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Specific Binding ◽  
Amyloid Β ◽  
Electrochemical Measurement ◽  
Charge Transfer Resistance ◽  
Chemical Agent ◽  
Transfer Resistance ◽  
K Value

Aggregation of amyloid-β (aβ) peptides into toxic oligomers, fibrils, and plaques is central in the molecular pathogenesis of Alzheimer’s disease (AD) and is the primary focus of AD diagnostics. Disaggregation or elimination of toxic aβ aggregates in patients is important for delaying the progression of neurodegenerative disorders in AD. Recently, 4-(2-hydroxyethyl)-1-piperazinepropanesulfonic acid (EPPS) was introduced as a chemical agent that binds with toxic aβ aggregates and transforms them into monomers to reduce the negative effects of aβ aggregates in the brain. However, the mechanism of aβ disaggregation by EPPS has not yet been completely clarified. In this study, an electrochemical impedimetric immunosensor for aβ diagnostics was developed by immobilizing a specific anti-amyloid-β (aβ) antibody onto a self-assembled monolayer functionalized with a new interdigitated chain-shaped electrode (anti-aβ/SAM/ICE). To investigate the ability of EPPS in recognizing AD by extricating aβ aggregation, commercially available aβ aggregates (aβagg) were used. Electrochemical impedance spectroscopy was used to probe the changes in charge transfer resistance (Rct) of the immunosensor after the specific binding of biosensor with aβagg. The subsequent incubation of the aβagg complex with a specific concentration of EPPS at different time intervals divulged AD progression. The decline in the Rct of the immunosensor started at 10 min of EPPS incubation and continued to decrease gradually from 20 min, indicating that the accumulation of aβagg on the surface of the anti-aβ/SAM/ICE sensor has been extricated. Here, the kinetic disaggregation rate k value of aβagg was found to be 0.038. This innovative study using electrochemical measurement to investigate the mechanism of aβagg disaggregation by EPPS could provide a new perspective in monitoring the disaggregation periods of aβagg from oligomeric to monomeric form, and then support for the prediction and handling AD symptoms at different stages after treatment by a drug, EPPS.

scholarly journals A new electrochemical sensor based on carbon paste electrode/Ru(III) complex for determination of nitrite: Electrochemical impedance and cyclic voltammetry measurements

Measurement ◽  
2016 ◽  
Vol 92 ◽  
pp. 524-533 ◽  
Author(s):  
Achour Terbouche ◽  
Siham Lameche ◽  
Chafia Ait-Ramdane-Terbouche ◽  
Djamila Guerniche ◽  
Djahida Lerari ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Sensor ◽  
Carbon Paste Electrode ◽  
Electrochemical Impedance ◽  
Carbon Paste ◽  
Paste Electrode

scholarly journals Investigation of Temperature and Aging Effects in Nanostructured Dye Solar Cells Studied by Electrochemical Impedance Spectroscopy

2009 ◽  
Vol 2009 ◽  
pp. 1-15 ◽  
Author(s):  
Minna Toivola ◽  
Janne Halme ◽  
Lauri Peltokorpi ◽  
Peter Lund
Keyword(s):  
Solar Cells ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Charge Transfer Resistance ◽  
Aging Effects ◽  
Transfer Resistance ◽  
Deterioration Rate ◽  
Dye Solar Cells ◽  
Effects Of Aging

Effects of aging and cyclically varying temperature on the electrical parameters of dye solar cells were analyzed with electrochemical impedance spectroscopy. Photoelectrode total resistance increased as a function of time due to increasing electron transport resistance in theTiO2film. On the other hand, photoelectrode recombination resistance was generally larger, electron lifetimes in theTiO2were film longer, and charge transfer resistance on the counter electrode was smaller after the temperature treatments than before them. These effects correlated with the slower deterioration rate of the temperature-treated cells, in comparison to the reference cells.

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