scholarly journals Experimental Design to Enhance Dopamine Electrochemical Detection Using Carbon Paste Electrodes

2021 ◽  
Vol 8 (32) ◽  
pp. 178-197
Author(s):  
Soraya Blum ◽  
Felipe Zahrebelnei ◽  
Noemi Nagata ◽  
Valtencir Zucolotto ◽  
Luiz Mattoso ◽  
...  
Keyword(s):  
Carbon Black ◽  
Modified Electrodes ◽  
Electrochemical Sensing ◽  
Current Response ◽  
Carbon Paste ◽  
Fast Determination ◽  
Intrinsically Conducting Polymers ◽  
Influence Of Ph ◽  
Central Composite

Efforts have been made on the development of new modified electrodes to be used in the fast determination of neurotransmitters, either in commercial drugs or in biological samples. Determination of dopamine (DA), for example, is of great importance since the lack of this neurotransmitter is related to many neurological disorders, including Parkinson’s and Alzheimer’s diseases. In this paper, we present a detailed electrochemical characterization, as well as DA detection studies of paste electrodes incorporating carbon materials in different allotropic forms, including carbon black modified with intrinsically conducting polymers (Eeonomers®), pristine carbon black, graphite, and carbon nanotubes. Emphasis is put on the smaller particle size and larger specific surface area of CB Eeonomers® materials, which led to an improved electroanalytical performance for the developed devices. The electrodes fabricated with Eeonomers® modified with polyaniline exhibited the higher current response towards DA detection, in addition to the ability of distinguishing DA from its natural interferent, ascorbic acid. Furthermore, a central composite design was used to investigate the influence of pH and electrode composition (proportion of Eeonomers®) on the electrochemical sensing of DA. A greater sensitivity was achieved for 50:50 (w/w) KP20/KPy20 electrode at pH 7.0. The optimized devices showed to be promising tools to perform quick, cheap and sensitive detection of this neurotransmitter in bioanalytical systems.

scholarly journals Efficient Electrochemical Sensor Based on Gold Nanoclusters/Carbon Ionic Liquid Crystal for Sensitive Determination of Neurotransmitters and Anti-Parkinson Drugs

2019 ◽  
Vol 10 (1) ◽  
pp. 46-55 ◽  
Author(s):  
Nada Farouk Atta ◽  
Ahmed Galal ◽  
Ekram Hamdy El-Ads ◽  
Aya Essam Galal
Keyword(s):  
Ionic Liquid ◽  
Liquid Crystal ◽  
Electrochemical Sensor ◽  
Gold Nanoclusters ◽  
Electrochemical Determination ◽  
Electrochemical Sensing ◽  
Current Response ◽  
Carbon Paste ◽  
Electro Catalytic Oxidation

Purpose: Herein we introduce a simple and sensitive sensor for the electrochemical determination of neurotransmitters compounds and anti-Parkinson drugs. Methods: The electrochemical sensor (Au/CILCE) based on gold nanoclusters modified carbon ionic liquid crystal (ILC) electrode was characterized using scanning electron microscopy and voltammetry measurements. Results: The effect of ionic liquid type in the carbon paste composite for the electro-catalytic oxidation of L-dopa was evaluated. Highest current response was obtained in case of ILC compared to other studied kinds of ionic liquids. The effective combination of gold nanoclusters and ILC resulted in extra advantages including large surface area and high ionic conductivity of the nanocomposite. L-dopa is considered one of the most important prescribed medicines for treating Parkinson’s disease. Moreover, a binary therapy using L-dopa and carbidopa proved effective and promising as it avoids the short comings of L-dopa mono-therapy for Parkinson’s patients. The Au/CILCE can detect L-dopa in human serum in the linear concentration range of 0.1 μM to 90 μM with detection and quantification limits of 4.5 nM and 15.0 nM, respectively. Also, the Au/CILCE sensor can simultaneously and sensitively detect L-dopa in the presence of carbidopa with low detection limits. Conclusion: The sensor is advantageous to be applicable for electrochemical sensing of other biologically electroactive species.

scholarly journals Voltammetric sensor based on long alkyl chain tetraalkylammonium ionic liquids comprising ascorbate anion for determination of nitrite

2021 ◽  
Vol 188 (2) ◽  
Author(s):  
Tomasz Rębiś ◽  
Michał Niemczak ◽  
Patrycja Płócienniczak ◽  
Juliusz Pernak ◽  
Grzegorz Milczarek
Keyword(s):  
Ionic Liquids ◽  
Electrostatic Interactions ◽  
Film Surface ◽  
Modified Electrodes ◽  
Voltammetric Sensor ◽  
Nitrite Oxidation ◽  
Alkyl Chains ◽  
Modified Surface ◽  
Influence Of Ph

AbstractAn electrochemical sensor was fabricated utilizing ionic liquids possessing cations with long alkyl chains such as trimethyl octadecylammonium and behenyl trimethylammonium and ascorbate anion. The ionic liquids were drop-coated onto the electrode. Thin modifying layers were prepared. Cyclic voltammetric investigations revealed electrostatic interactions between the electrochemical probes and the modified surface, proving that a positive charge was established at the film surface. Hence, negatively charged species such as nitrite can be pre-concentrated on the surface of presented modified electrodes. The fabricated electrodes have been used as a voltammetric sensor for nitrite. Due to the electrostatic accumulation properties of long alkyl cation, the assay exhibits a remarkable improvement in the voltammetric response toward nitrite oxidation. The influence of pH on the electrode response was thoroughly investigated, and the mechanism of the electrode was established. The developed sensor showed a linear electrochemical response in the range 1.0–50 μM with a detection limit of 0.1 μM. The electrode revealed good storage stability, reproducibility, and anti-interference ability. The determination of nitrite performed in curing salts brought satisfactory results. Graphical abstract

scholarly journals A Sensitive and Low-cost Analytical Method for the Electrochemical Determination of Quercetin, Based on 1-Ethylpyridinium Bromide/Carbon Paste Composite Electrode

2015 ◽  
Vol 7 (2) ◽  
pp. 27 ◽  
Author(s):  
Francis Tchieno ◽  
Ignas Tonle ◽  
Evangeline Njanja ◽  
Emmanuel Ngameni
Keyword(s):  
Carbon Paste Electrode ◽  
Analytical Method ◽  
Composite Electrode ◽  
Low Cost ◽  
Reduction Peak ◽  
Cyclic Voltammogram ◽  
Current Response ◽  
Carbon Paste ◽  
Paste Electrode

We report a simple, sensitive and low-cost electrochemical procedure for the quantification of quercetin (QCT), a flavonoid and an antioxidant, based on 1-ethylpyridinium bromide modified carbon paste electrode. A 1-ethylpyridinium bromide/carbon paste composite electrode was used. The cyclic voltammogram of QCT showed two oxidation peaks at +0.575 V (vs Ag/AgCl/3M KCl) and +0.865 V (vs Ag/AgCl/3M KCl), and a reduction peak at +0.371 V (vs Ag/AgCl/3M KCl) in HCl/KCl solution at pH 1. Differential pulse voltammetry (DPV) analysis in HCl/KCl at pH 1 showed three well-defined oxidation peaks while a single peak was recorded in phosphate buffer at pH 3. The peak currents of QCT significantly increased at the 1-ethylpyridinium bromide modified electrode in comparison with those recorded at the bare carbon paste electrode. This allowed the use of adsorptive stripping voltammetry to develop a simple and sensitive electroanalytical method for the determination of QCT. Key experimental parameters such as pH of the supporting electrolyte, the preconcentration time, the electrolysis potential, electrode composition, QCT concentration and interferents were investigated. The current response was found to be directly proportional to the concentration of QCT in the range from 2.48 x 10-7 M to 7.43 x 10-6 M, leading to a detection limit of 4.48 x 10-8 M. The developed analytical method was successfully applied to the determination of QCT in human urine samples.

scholarly journals Online Coupling of Lab-on-Valve Format to Amperometry Based on Polyvinylpyrrolidone-Doped Carbon Paste Electrode and Its Application to the Analysis of Morin

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Yang Wang ◽  
Guojun Yao ◽  
Jie Tang ◽  
Chun Yang ◽  
Qin Xu ◽  
...  
Keyword(s):  
Carbon Paste Electrode ◽  
Supporting Electrolyte ◽  
Phosphate Buffer Solution ◽  
Current Response ◽  
Oxidation Peak ◽  
Carbon Paste ◽  
Buffer Solution ◽  
Electrochemical Behaviors ◽  
Paste Electrode

The potential capabilities and analytical performance of lab-on-valve (LOV) manifold as a front end to amperometry have been explored for the on-line determination of morin. Meanwhile, the electrochemical behaviors of morin were investigated based on polyvinylpyrrolidone- (PVP-) doped carbon paste electrode (CPE), which found that PVP can significantly improve its oxidation peak current. The excellent amperometric current response was achieved when the potential difference (ΔE) of 0.6 V was implemented in pH 6.5 phosphate buffer solution (PBS) that served as the supporting electrolyte. A well-defined oxidation peak has been obtained in studies using PVP as a modifier of CPE based on the oxidation of morin. The present work introduces the LOV technique as a useful tool for amperometric measurement, documents advantages of using programmable flow, and outlines means for miniaturization of assays on the basis of PVP modified CPE. The proposed method was applied successfully to the determination of morin in real samples, and the spiked recoveries were satisfactory.

scholarly journals Electrochemical determination of atenolol and propranolol using a carbon paste sensor modified with natural ilmenite

2021 ◽  
Vol 19 (1) ◽  
pp. 875-883
Author(s):  
Nevila Broli ◽  
Majlinda Vasjari ◽  
Loreta Vallja ◽  
Sonila Duka ◽  
Alma Shehu ◽  
...  
Keyword(s):  
Carbon Paste Electrode ◽  
Beta Blockers ◽  
High Sensitivity ◽  
Modified Carbon Paste Electrode ◽  
Current Response ◽  
Carbon Paste ◽  
Linear Calibration ◽  
Pharmaceutical Tablets ◽  
Paste Electrode

Abstract In this study, a simple voltammetric method was reported for independent determination of propranolol (PROP) and atenolol (ATN) in pharmaceutical tablets using carbon paste electrode modified with natural Ilmenite (CPE-I). The analytical performance of the modified sensor was evaluated using the square wave voltammetry and cyclic voltammetry for determination of both β(beta) blockers in 0.1 mol L−1 of sulfuric acid solution (H2SO4). The signal obtained with modified carbon paste electrode in 0.1 mol L−1 of H2SO4 showed a good electrocatalytic activity toward the oxidations of PROP and ATN compared with the bare one. The enhanced oxidation peak current response can be attributed to the catalytic effect of the ilmenite nanomaterial incorporated into the carbon paste electrode. Under optimal condition, good linear calibration curves were obtained ranging from 0.20 to 8.9 mmol L−1 for PROP and 2.0 to 9.9 µmol L−1 for ATN, with detection limits of 80 and 0.31 µmol L−1, respectively. The CPE-I sensor had good repeatability and reproducibility (RSD ≤ 3.2%) and high sensitivity for the detection of both ATN and PROP. The proposed sensor was applied for detection of these drugs in pharmaceutical tablets. The obtained results indicate that the voltammetric CPE-I sensor could be an alternative method for the routine quality control of the β blockers in complex matrices.

Designed electrochemical sensor based on metallocene modified conducting polymer composite for effective determination of tramadol in real samples

2020 ◽  
Author(s):  
Nada F. Atta ◽  
Ghada Abdo ◽  
Ahmed Elzatahry ◽  
Ahmed Galal ◽  
Samar Hassan
Keyword(s):  
Sodium Dodecyl ◽  
Electrochemical Sensing ◽  
Electronic Conduction ◽  
Current Response ◽  
Good Resolution ◽  
Practical Application ◽  
Serum Samples ◽  
High Reproducibility ◽  
Urine And Serum

A novel composite for the electrochemical sensing of tramadol (Tr) was developed by the inclusion of metallocene mediator between two layers of conducting poly(3,4-ethylenedioxythiophene) (PEDOT) polymer, in presence of sodium dodecyl sulfate (SDS); (P/mediator/P…SDS). Three charge transfer mediators were evaluated: ferrocene carboxylic acid (FC1), ferrocene (FC2) and cobaltocene (CC) for Tr electrocatalytic oxidation. FC1-charge mediator showed relatively higher current response that was assisted by the electronic conduction of the polymer film. Moreover, SDS presented a great impact, resulting in the enhancement of the preconcentration/accumulation of Tr ions at the interface leading to faster electron transfer. In addition, the practical application of the proposed FC1 composite for the determination of Tr in real urine and serum samples was successfully achieved with adequate recovery results. Very low detection limits of 18.6 nM and 16 nM in the linear dynamic ranges of 7 µM to 300 µM and 5 µM to 280 µM, respectively, were obtained at the proposed sensor. Furthermore, the simultaneous determination of of Tr with common interfering species; paracetamol (PAPA), morphine (MO), dopamine (DA), ascorbic acid (AA) and uric acid (UA) proved excellent with good resolution and large potential peaks separation. The excellent characteristics of the proposed composite such as high reproducibility, good sensitivity, selectivity, anti-interference ability and good stability enhanced its application for determination of other narcotics drugs.

Cobalt porphyrins immobilized on niobium(V) oxide grafted on a silica gel surface: study of the catalytic reduction of dissolved dioxygen

2001 ◽  
Vol 05 (06) ◽  
pp. 537-544 ◽  
Author(s):  
CHRISTIANA A. PESSÔA ◽  
YOSHITAKA GUSHIKEM
Keyword(s):  
Silica Gel ◽  
Catalytic Reduction ◽  
Protoporphyrin Ix ◽  
Modified Electrodes ◽  
Rotating Disk ◽  
Local Symmetry ◽  
Carbon Paste ◽  
Cobalt Porphyrins ◽  
Hematoporphyrin Ix

Hematoporphyrin IX, H 2 HMP , 8,13-bis(1-hydroxyethyl)-3,7,12,17-tetramethyl-21 H ,23 H -porphine-2,18-dipropionic acid and protoporphyrin IX, H 2 PP , 8,13-divinyl-3,7,12,17-tetramethyl-21 H ,23 H -porphine-2,18-dipropionic acid were efficiently immobilized on niobium oxide grafted on a silica gel surface, SiO 2/ Nb 2 O 5, by the - COO – Nb bond formed between the porphyrin carboxyl groups and the grafted Nb 2 O 5. These immobilized porphyrins, SiO 2/ Nb 2 O 5/ H 2 HMP and SiO 2/ Nb 2 O 5/ H 2 PP , were further reacted with Co (II) in dimethylformamide, resulting in SiO 2/ Nb 2 O 5/ CoHMP and SiO 2/ Nb 2 O 5/ CoPP metallated complexes. The UV-vis spectra of the solid materials showed changes of the Q-bands ( a 2 u → e g transition) upon metallation, indicating that by incorporation of Co (II) in the porphyrin ring the local symmetry changed from D2 h to D4 h . These materials, when incorporated in carbon paste electrodes, presented the property of electrocatalyzing O 2 reduction. Rotating disk experiments were performed in order to estimate the number of electrons involved in the process. It was observed that, for both modified electrodes, O 2 was reduced to water in a four-electron process. Amperometric studies showed the potentiality of both modified electrodes as sensors for the determination of dissolved dioxygen. The response time was less than 3 s. A linear response for both systems was obtained between 2 and 12 ppm.

Application of nickel cobalt oxide nanoflakes for electrochemical sensing of estriol in milk

RSC Advances ◽  
2016 ◽  
Vol 6 (70) ◽  
pp. 65588-65593 ◽  
Author(s):  
Hui-Jun Fu ◽  
Yu Wang ◽  
Xiu-Xiu Dong ◽  
Yi-Xin Liu ◽  
Zi-Jian Chen ◽  
...  
Keyword(s):  
Electrochemical Sensor ◽  
Cobalt Oxide ◽  
Electrochemical Sensing ◽  
Fast Determination ◽  
Nickel Cobalt ◽  
Nickel Cobalt Oxide ◽  
First Time

In this work, a nickel cobalt oxide (Ni/Co oxide) nanoflake based electrochemical sensor for the fast determination of estriol in milk is presented for the first time.

scholarly journals Gold Electrodes Modified with Self-Assembled Layers Made of Sulphur Compounds and Gold Nanoparticles Used for Selective Electrocatalytic Oxidation of Catecholamine in the Presence of Interfering Ascorbic and Uric Acids

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Teresa Łuczak
Keyword(s):  
Gold Nanoparticles ◽  
Detection Limit ◽  
Electrocatalytic Oxidation ◽  
Modified Electrodes ◽  
Gold Electrodes ◽  
Current Response ◽  
Good Sensitivity ◽  
Sulphur Compounds ◽  
Peak Separation

Gold electrodes modified with S-containing compounds and gold nanoparticles were used for determination of epinephrine (EP) in aqueous solution. The modified electrodes exhibited a good sensitivity, reproducibility, and stability. The results have shown that modified electrodes could clearly resolve the oxidation peaks of epinephrine, ascorbic acid (AA), and uric acid (UA) with peak-to-peak separation enabling determination of EP, AA, and UA in their simultaneous presence. A linear relationship between EP concentration and current response was obtained in the range of 0.1 μM to 700 μM with the detection limit ≥0.034 μM for the electrodes modified at 2D template and in the range of 0.1 μM to 800 μM with the detection limit ≥0.030 μM for the electrodes modified at 3D template.

scholarly journals Effect of RGO-Y2O3 and RGO-Y2O3:Cr3+ nanocomposite sensor for dopamine

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
J. K. Shashikumara ◽  
Bhimanagouda Kalaburgi ◽  
B. E. Kumara Swamy ◽  
H. Nagabhushana ◽  
S. C. Sharma ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Emission Spectra ◽  
Modified Electrodes ◽  
Current Response ◽  
Carbon Paste ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carbon Paste Electrodes ◽  
Transmission Electron ◽  
Voltammetric Detection

AbstractThe RGO-Y2O3 and RGO-Y2O3: Cr3+ (5 mol %) nanocomposite (NC) synthesized by hydrothermal technique. The structure and morphology of the synthesized NCs were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Y2O3:Cr3+ displays spherical-shaped particles. Conversely, the surface of the RGO displays a wrinkly texture connecting with the existence of flexible and ultrathin graphene sheets. The photoluminescence (PL) emission spectra showed series of sharp peaks at 490, 591, and 687 nm which corresponding to 4F9/2 → 6H15/2, 4F9/2 → 6H13/2, and 4F9/2 → 6H11/2 transitions and lies in the blue, orange, and red region. The prepared NCs were used for the preparation of modified carbon paste electrodes (MCPE) in the electrochemical detection of dopamine (DA) at pH 7.4. Both modified electrodes provide a good current response towards voltammetric detection of DA. Doping is an effective method to improve the conductivity of Y2O3:Cr3+ and developed a method for the sensor used in analytical applications.

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