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.

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.

Fabrication of Graphene/Carbon Nanotube Composite Modified Electrode for Selective and Sensitive Determination of Uric Acid

2013 ◽  
Vol 641-642 ◽  
pp. 562-565
Author(s):  
Zheng Xiao Liu ◽  
Jian Fei Xia ◽  
Zong Hua Wang ◽  
Yan Zhi Xia ◽  
Fei Fei Zhang ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Uric Acid ◽  
Carbon Nanotube ◽  
Modified Electrode ◽  
Phosphate Buffer Solution ◽  
Carbon Electrode ◽  
Buffer Solution ◽  
Sensitive Determination ◽  
Carbon Nanotube Composite

A novel composite was firstly synthesized by compositing graphenes (G) and carbon nanotubes (CNTs) and then a new composite modified electrode (G/CNTs/GCE) was prepared by coating the resulting composite on the surface of the glassy carbon electrode (GCE). The composite modified electrode G/CNTs/GCE showed great electrochemical activities which were studied by sensitive determining the electrochemistry behaviors of uric acid (UA). It revealed when the concentration range of UA changed from 1×10-7 mol/L to 1×10-3 mol/L, the peak currents had linear relationship with the concentration of UA in the phosphate buffer solution (PBS) which the value of pH is 7.0. And the linear equation is ip (μA) = 21.55C+28.94 (C: mmol/L), with the related coefficient 0.9964.

Electrochemistry and Electrocatalysis of Hemoglobin Based on Graphene Quantum Dots Modified Electrode

2020 ◽  
Vol 16 (3) ◽  
pp. 308-315
Author(s):  
Xiaoyan Li ◽  
Hui Xie ◽  
Guiling Luo ◽  
Yanyan Niu ◽  
Xiaobao Li ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Modified Electrode ◽  
Electrochemical Impedance ◽  
Ph Value ◽  
Catalytic Reduction ◽  
Graphene Quantum Dots ◽  
Phosphate Buffer Solution ◽  
Buffer Solution ◽  
Detection Range ◽  
Electrochemical Behaviors

Background: Graphene quantum dots (GQD) is a new member of carbon nanomaterial that has attracted increasing attention owing to its better chemical inertness, low cytotoxicity, large specific surface area, cheap cost, suitable conductivity and excellent biocompatibility. Methods: Electrochemical behaviors of this modified electrode were studied by cyclic voltammetry and electrochemical impedance spectroscopy. Electrochemical investigations of Nafion/Hb/GQD/ CILE were carried out with electrochemical parameters calculated. Results: In the phosphate buffer solution with a pH value of 5.0, good linear relationships between the catalytic reduction current and the concentration of substrate were got for TCA (6.0~100.0 mmol·L-1), NaNO2 (2.0~12.0 mmol·L-1) and H2O2 (6.0~30.0 mmol·L-1). The proposed method was applied to NaNO2 concentration detection in soak water from picked vegetables with satisfactory results. Conclusion: This Nafion/Hb/GQD/CILE had a good bioelectrocatalytic activity to different substrates such as trichloroacetic acid, NaNO2 and H2O2 reduction with the advantages including wide detection range, low detection limit and good stability. Therefore, the application of GQD in electrochemical sensor was extended in this paper.

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.

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.

Determination of the size, shape, and composition of indium-flushed self-assembled quantum dots by transmission electron microscopy

2000 ◽  
Vol 88 (5) ◽  
pp. 2272-2277 ◽  
Author(s):  
J. P. McCaffrey ◽  
M. D. Robertson ◽  
S. Fafard ◽  
Z. R. Wasilewski ◽  
E. M. Griswold ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Dots ◽  
Transmission Electron ◽  
Self Assembled

The determination of the size and shape of buried InAs/InP quantum dots by transmission electron microscopy

2005 ◽  
Vol 103 (3) ◽  
pp. 205-219 ◽  
Author(s):  
M.D. Robertson ◽  
J.C. Bennett ◽  
A.M. Webb ◽  
J.M. Corbett ◽  
S. Raymond ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Dots ◽  
Size And Shape ◽  
Transmission Electron ◽  
Inp Quantum Dots

Immobilization of Porcine pancreatic Lipase on Vesicle-Like Silica Material with Large Pore

2012 ◽  
Vol 485 ◽  
pp. 314-317
Author(s):  
Cui Cui Wu ◽  
Guo Wei Zhou ◽  
De Lan Xu ◽  
Tian Duo Li
Keyword(s):  
Electron Microscopy ◽  
Cetyltrimethylammonium Bromide ◽  
Physical Adsorption ◽  
Sodium Dodecyl ◽  
Phosphate Buffer Solution ◽  
Buffer Solution ◽  
Excellent Thermal Stability ◽  
Silica Material ◽  
Transmission Electron ◽  
Adsorption Desorption

Vesicle-like silica (VS) was prepared by utilizing cationic surfactant cetyltrimethylammonium bromide (CTAB) and anionic surfactant sodium dodecyl sulfate (SDS) as a dual-template. The mesostructures of VS were characterized by N2adsorption-desorption isotherms, field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). Results showed that mean mesopore size of unilayer and multilayer VS was about 14 nm and shell thickness was nearly 6 nm. The VS was chosen as support for immobilization of Porcine pancreatic lipase (PPL) by physical adsorption. The immobilized PPL possessed excellent thermal stability and reusability in the hydrolysis reaction of triacetin in phosphate buffer solution.

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