scholarly journals Carvacrol electrochemical reaction characteristics on screen printed electrode modified with La2O3/Co3O4 nanocomposite

2019 ◽  
Vol 9 (2) ◽  
pp. 113-123 ◽  
Author(s):  
Sayed Zia Mohammadi ◽  
Hadi Beitollahi ◽  
Tahereh Rohani ◽  
Hossein Allahabadi
Keyword(s):  
Limit Of Detection ◽  
Phosphate Buffer Solution ◽  
Differential Pulse ◽  
Co3o4 Nanoparticles ◽  
Electrochemical Characteristics ◽  
Screen Printed Electrode ◽  
Buffer Solution ◽  
Voltammetric Techniques ◽  
Screen Printed

Electrochemical characteristics of carvacrol were investigated on a screen-printed electrode (SPE) modified with La2O3/Co3O4 nanocomposite by using voltammetric techniques, which displayed a well-defined peak for sensitive carvacrol determination in phosphate buffer solution (PBS) at pH 7.0. La2O3/Co3O4 nanoparticles demonstrated suitable catalytic activity for carvacrol determination by differential pulse voltammetry (DPV) technique. Besides, determination of carvacrol in a real samples was recognized in the light of electrochemical findings and a validated voltammetric technique for quantitative analysis of carvacrol in a real formulation was proposed. The DPV peak currents were found to be linear in the concentration range of 10.0 to 800.0 μM. The limit of detection (LOD) was found to be 1.0 μM.

scholarly journals A novel dopamine electrochemical sensor based on La3+/ZnO nanoflower modified graphite screen printed electrode

2019 ◽  
Vol 9 (3) ◽  
pp. 187-195 ◽  
Author(s):  
Somayeh Tajik ◽  
Hadi Beitollahi ◽  
Mohammad Reza Aflatoonian
Keyword(s):  
Modified Electrode ◽  
Phosphate Buffer Solution ◽  
High Sensitivity ◽  
Differential Pulse ◽  
Electrochemical Determination ◽  
Screen Printed Electrode ◽  
Buffer Solution ◽  
Optimized Conditions ◽  
Screen Printed

Flower-like La3+/ZnO nanocomposite was facile synthesized. A simple and ultrasensitive sensor based on graphite screen printed electrode (SPE) modified by La3+/ZnO nanoflower was developed for the electrochemical determination of dopamine. The electrochemical behavior of dopamine was studied in 0.1 M phosphate buffer solution (PBS) using cyclic voltammetry (CV), chronoamperometry (CA) and differential pulse voltammetry (DPV). Compared with the unmodified graphite screen printed electrode, the modified electrode facilitates the electron transfer of dopamine, since it notably increases the oxidation peak current of dopamine. Also, according to CV results the maximum oxidation of dopamine on La3+/ZnO/SPE occurs at 150 mV which is about 140 mV more negative compared with unmodified SPE. Under optimized conditions, the modified electrode exhibited a linear response over the concentration range from 0.15 to 300.0 μM, with a detection limit of 0.08 μM (S/N = 3). The proposed sensor exhibited a high sensitivity, good stability and was successfully applied for dopamine determination in dopamine ampoule, with high recovery.

Sensitive Determination of Epinephrine in the Presence of Ascorbic Acid at Poly(diphenylamine sulfonic acid) Modified Sensor

2020 ◽  
Vol 18 (4) ◽  
pp. 253-258
Author(s):  
Gamze Erdoğdu
Keyword(s):  
Ascorbic Acid ◽  
Sulfonic Acid ◽  
Limit Of Detection ◽  
Phosphate Buffer Solution ◽  
Differential Pulse ◽  
Buffer Solution ◽  
Sensitive Determination ◽  
Pulse Voltammetry ◽  
Modified Sensor

A sensitive and simple modified sensor was prepared by electrodeposition of diphenylamine sulfonic acid (DPSA) to the glassy carbon electrode surface by cyclic voltammetry (CV) technique. The electrooxidation of epinephrine (EP) was accomplished by CV and differential pulse voltammetry at poly(DPSA) modified sensor. As a result of the findings, the current values were enhanced and both substances were separated at the modified sensor compared to the bare electrode. There was linearly between the oxidation current and concentration of EP from 0.2 to 100 μM in phosphate buffer solution at pH 7.0. The limit of detection was 5.0 nM and the sensitivity was 0.4205 μA/μM. The determination of EP was successfully and satisfactorily carried out in real samples such as human blood serum and urine at the poly(DPSA) sensor. To the best knowledge of this work, this is the first study that detect the EP in the presence of ascorbic acid at poly(DPSA) sensor in the literature.

scholarly journals Electrochemical Polymerised Graphene Paste Electrode and Application to Catechol Sensing

2019 ◽  
Vol 13 (1) ◽  
pp. 81-87 ◽  
Author(s):  
Jamballi G. Manjunatha
Keyword(s):  
Modified Electrode ◽  
Limit Of Detection ◽  
Phosphate Buffer Solution ◽  
Sample Pretreatment ◽  
Differential Pulse ◽  
Buffer Solution ◽  
Solution Ph ◽  
Graphene Paste Electrode ◽  
Paste Electrode

Objective: To build up an advantageous strategy for sensitive determination of catechol (CC), a poly (proline) modified graphene paste electrode (PPMGPE) was fabricated and used as a voltammetric sensor for the determination of CC. Methods: The performance of the modified electrode was studied using cyclic voltammetric (CV) and differential pulse voltammetric method (DPV). The modified electrode was characterized by CV and DPV. The surface of the modified electrode was examined by FESEM. The electrochemical behavior of CC in phosphate buffer solution (pH 7.5) was inspected using bare graphene paste electrode (BGPE) and PPMGPE. Results & Conclusion: The PPMGPE shows a lower limit of detection, calculated to be 8.7×10–7mol L−1 (S/N=3). This modified electrode was applied successfully for the determination of CC in water samples without applying any sample pretreatment.

scholarly journals Electrochemical sensor for determination of hydroxylamine using functionalized Fe3O4 nanoparticles and graphene oxide modified screen-printed electrode

2021 ◽  
Author(s):  
Hamed Tashakkorian ◽  
Behnaz Aflatoonian ◽  
Peyman Mohammadzadeh Jahani ◽  
Mohammad Reza Aflatoonian
Keyword(s):  
Graphene Oxide ◽  
Electrochemical Sensor ◽  
Fe3o4 Nanoparticles ◽  
Phosphate Buffer Solution ◽  
Electrochemical Process ◽  
Screen Printed Electrode ◽  
Buffer Solution ◽  
Solution Ph ◽  
Screen Printed

A simple strategy for determination of hydroxylamine based on Fe3O4 nanoparticles function­nalized by [2-(4-((3-(trimethoxysilyl)propylthio)methyl)1-H1,2,3-triazol-1-yl)acetic­acid] (FNPs) and graphene oxide (GO) modified screen-printed electrode (SPE), denoted as (Fe3O4 FNPs/GO/SPE), is reported. The electrochemical behavior of hydroxylamine was investigated at Fe3O4FNPs/GO/SPE by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chro­noamperometry (CHA) techniques in phosphate buffer solution (pH 7.0). Fe3O4 FNPs/GO/SPE as a novel electrochemical sensor exhibited catalytic activity toward the oxidation of hydroxyl­ami­ne. The potential of hydroxylamine oxidation was shifted to more negative potentials, and its oxidation peak current increased on the modified electrode, also indicating that under these conditions, the electrochemical process is irreversible. The electrocatalytic current of hydroxyl­amine showed a good relationship in the concentration range of 0.05–700.0 μM, with a detection limit of 10.0 nM. The proposed electrode was applied for the determination of hydroxyl­amine in water samples, too.

Electrochemical Determination of Norepinephrine at Poly (p-aminobenzenesulfonic Acid) Modified Sensor

2020 ◽  
Vol 16 (5) ◽  
pp. 591-600
Author(s):  
Şevket Zişan Yağcı ◽  
Ebru Kuyumcu Savan ◽  
Gamze Erdoğdu
Keyword(s):  
Ascorbic Acid ◽  
Limit Of Detection ◽  
Phosphate Buffer Solution ◽  
Differential Pulse ◽  
Electrochemical Determination ◽  
Buffer Solution ◽  
Oxidation Current ◽  
Pulse Voltammetry ◽  
Modified Sensor

Objective: In this study, it was aimed to prepare an electrochemical sensor capable of assigning Norepinephrine in the presence of an interference such as ascorbic acid. Methods: A sensitive modified sensor was prepared by electrodeposition of p-aminobenzenesulfonic acid (p-ABSA) to the glassy carbon electrode by cyclic voltammetry. The electrooxidation of Norepinephrine was accomplished by cyclic and differential pulse voltammetry. Results: The current values were enhanced and the peak potentials of Norepinephrine and ascorbic acid were separated at the sensor compared to the bare electrode. There was linearity between the oxidation current and concentration of Norepinephrine ranging from 0.5 to 99.8 μM in phosphate buffer solution at pH 7.0. The limit of detection was 10.0 nM and the sensitivity was 0.455 μA/μM. Conclusion: The determination of Norepinephrine was successfully performed in real samples such as blood serum and urine at the poly (p-ABSA) sensor. To the best of our knowledge, this is the first study to detect Norepinephrine in the presence of ascorbic acid at poly (p-ABSA) modified sensor in the literature.

scholarly journals Determination of Simvastatin by Voltammetry Method at Screen-Printed Electrode Modified by Graphene Oxide Nanosheets and Sodium Dodecyl Sulfate

2022 ◽  
Author(s):  
Abolfazl Darroudi ◽  
Saeid Nazari ◽  
Seyed Ali Marashi ◽  
Mahdi Karimi-Nazarabad
Keyword(s):  
Graphene Oxide ◽  
Sodium Dodecyl Sulfate ◽  
Limit Of Detection ◽  
Sodium Dodecyl ◽  
Screen Printed Electrode ◽  
Support Electrolyte ◽  
Limit Of Quantitation ◽  
Dodecyl Sulfate ◽  
Screen Printed

Abstract An accurate, rapid, simple, and novel technique was developed to determine simvastatin (SMV). In this research, a screen-printed electrode (SPE) was deposited with graphene oxide (GO) and sodium dodecyl sulfate (SDS), respectively. For the first time, the handmade modified SPE measured the SMV by differential pulse voltammetry (DPV) with high sensitivity and selectivity. The results of cyclic voltammetry indicated the oxidation irreversible process of SMV. Various parameters (pH, concentration, scan rate, support electrolyte) were performed to optimize the conditions for the determination of SMV. Under the optimum experiment condition of 0.1 M KNO3 as support electrolyte and pH 7.0, the linear range was achieved for SMV concentration from 1.8 to 36.6 µM with a limit of detection (LOD), and a limit of quantitation (LOQ) of 0.06 and 1.8 µM, respectively. The proposed method was successfully utilized to determine SMV in tablets and urine samples with a satisfactory recovery in the range of 96.2 to 103.3%.

Enhanced Electrochemical Determination Of Riboflavin In Biological And Pharmaceutical Samples At Poly (Arginine) Modified Carbon Paste Electrode

2019 ◽  
Vol 14 (4) ◽  
pp. 216-223 ◽  
Author(s):  
Girish Tigari ◽  
J.G. Manjunatha ◽  
D.K. Ravishankar ◽  
G. Siddaraju
Keyword(s):  
Carbon Paste Electrode ◽  
Limit Of Detection ◽  
Phosphate Buffer Solution ◽  
Differential Pulse ◽  
Modified Carbon Paste Electrode ◽  
Current Response ◽  
Carbon Paste ◽  
Serum Samples ◽  
Buffer Solution ◽  
Paste Electrode

An electrogenerated Polyarginine modified carbon paste electrode (PAMCPE) was fabricated through a simple electropolymerization procedure. The devised electrode was characterized by cyclic voltammetry (CV) and Field Emission Scanning Electron Microscopy (FESEM). This electrode was utilized for electrocatalytic estimation of Riboflavin (RF) and its instantaneous resolution with ascorbic acid (AA) and folic acid (FA) in phosphate buffer solution (PBS) of pH 6.0 by differential pulse voltammetry (DPV). It was observed to be a very responsive electrode for the electrochemical detection and quantification of RF. It was revealed that PAMCPE generates higher current response towards RF contrast to the bare carbon paste electrode (BCPE). Under optimized condition, the RF oxidation current values were linearly reliant on the RF concentration increment with a limit of detection (LOD) of 9.3·10-8 M using DPV. The stable PAMCPE was effectively applied for estimation of RF in B-complex pill and complex human blood serum samples.

Cadmium Selenide Quantum Dots - MWCNTs Nanocomposite Modified Electrode for the Determination of Epinephrine

2014 ◽  
Vol 938 ◽  
pp. 176-181 ◽  
Author(s):  
Arumugam Kalaivani ◽  
Sangilimuthu Sriman Narayanan
Keyword(s):  
Electron Microscopy ◽  
Quantum Dots ◽  
Cadmium Selenide ◽  
Modified Electrode ◽  
Phosphate Buffer Solution ◽  
Electrochemical Characteristics ◽  
Buffer Solution ◽  
Transmission Electron ◽  
Cadmium Selenide Quantum Dots

A novel Cadmium selenide Quantum dots MWCNTs nanocomposite modified electrode was achieved by simple drop casting method and its application towards the quantitative determination of epinephrine. The Cadmium selenide Quantum Dots was characterized by transmission electron microscopy and MWCNT was characterized by scanning electron microscopy. The electrochemical characteristics of the modified electrode were studied using cyclic voltammetry. The voltammetric response of the modified electrode was higher than that of the MWCNT and bare electrodes. The modified electrode exhibits excellent electrocatalytic activity towards the oxidation of epinephrine by enhancing its oxidation current in 0.1M phosphate buffer solution. The determination range of epinephrine is from 0.16 μM to 14 μM and the detection limit was 0.05 μM (S/N = 3). The proposed modified electrode exhibited good stability and reproducibility.

The Application of Glassy Carbon Electrode Modified by Multi-Walled Carbon Nanotubes for the Fast Determination of Hydroquinone in Wastewater

2014 ◽  
Vol 955-959 ◽  
pp. 1160-1166
Author(s):  
Shao Hua Li ◽  
Ying Ying Zhao ◽  
Jun Qing Yang ◽  
Guo Yan Zhang ◽  
Ju Rui Qi
Keyword(s):  
Carbon Nanotubes ◽  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Phosphate Buffer Solution ◽  
Differential Pulse ◽  
Carbon Electrode ◽  
Buffer Solution ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

A novel multi-walled carbon nanotubes (MWCNTs)-modified glassy carbon electrode (GCE) with excellent stability, repeatability and anti-interference was synthesized and it exhibited an electrocatalytic signal for hydroquinone (HQ) compared to bare GCE, which suggested that the presence of MWCNTs efficiently enhances electron transfer. Various parameters such as pH, modifier volume, and scan rate were optimized using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods. Under optimum conditions, linear responses for HQ in 0.1mol·L-1 phosphate buffer solution of pH 6.0 were obtained in the range of 5×10-6 mol·L-1 to 2×10-4 mol·L-1 with detection limits of 2.7×10-6 mol·L-1 (signal-to-noise ratio of 3). Such MWCNTs-modified GCE was successfully applied for the determination of hydroquinone in simulated water samples and can be developed for the the detection of HQ.

A Renewable Amperometric Immunosensor for hs-CRP Based on Functionalized Fe3O4@Au Magnetic Nanoparticles Attracted on Fe (III) Phthlocyanine/Chitosan-Membrane Modified Screen-Printed Carbon Electrode by a Magnet

2011 ◽  
Vol 110-116 ◽  
pp. 519-526 ◽  
Author(s):  
Ning Gan ◽  
Ling Hua Meng ◽  
Fu Tao Hu ◽  
Yu Ting Cao ◽  
Yuan Zhao Wu ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Rapid Determination ◽  
Phosphate Buffer Solution ◽  
Carbon Electrode ◽  
Buffer Solution ◽  
Chitosan Membrane ◽  
Screen Printed Carbon Electrode ◽  
Hs Crp ◽  
Screen Printed

A novel disposable screen-printed immunosensor for rapid determination of highly sensitive C reactiveprotein (hs-CRP) in human serum has been developed in the experiment. The sensor was constructed on one screen-printed carbon electrode (SPCE) with HRP labeled anti-hs-CRP antibody functionalized Fe3O4@Au magnetic nanoparticles (HRP labeled anti hs-CRP/ Fe3O4@Au) as the biorecognition probes attracted on the surface of Fe (III) phthalocyanine (FePc)/ chitosan membrane modified screen-printed carbon electrode (SPCE|FePc/Chit/chitosan) by external magnetic field. FePc was acted as electron immediate. The modified electrode shows an excellent electrocatalytic activity for hs-CRP in phosphate buffer solution (pH=7.0). After the immunosensor is incubated with hs-CRP antigen solution at 37°C for 20 min, the access of activity center of the HRP to electrode is partly inhibited, which leads to a linear decrease of the catalytic efficiency of the HRP to the reduction of immobilized FePc by H2O2 at –50 mV in hs-CRP’s concentration ranges from 1.2 to 200 ng/mL. The detection limit was 0.5ng/mL. The immunosensor was successfully utilized for determination of hs-CRP in real serum samples of heart disease patients, whose results were consistent with that by ELISA method. The accuracy and precision of the assay were 91.5-104.4% and 15.8-24.4%, respectively. The immunosensor was reusable once constructed and can be regenerated by adding new nanoprobes on the surface of basal electrode through magnet on its bottom. It can greatly reduce the detection cost which is valuable for the early diagnosis of tumors.

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