Electrosynthesis and electrochemical characteristics of 2,2′-(4,5-dihydroxy-3-methoxy-1,2-phenylene)bis(3-oxo-3-phenylpropanenitrile): application as a mediator for determination of hydroxylamine at a carbon nanotube modified electrode surface

2014 ◽  
Vol 6 (15) ◽  
pp. 5999-6008 ◽  
Author(s):  
Hamid R. Zare ◽  
Milad Tashkili ◽  
Hossein Khoshro ◽  
Davood Nematollahi ◽  
Ali Benvidi

Electrosynthesis and electrochemical characteristics of an electrodeposited DMPP film on a multi-wall carbon nanotube modified glassy carbon electrode and its role as a mediator for electrocatalytic oxidation of hydroxylamine.

2011 ◽  
Vol 14 (3) ◽  
pp. 183-189
Author(s):  
Yong-Ping Dong ◽  
Qian-Feng Zhang ◽  
Taike Duan

A gold nanoparticle/carbon nanotube composite modified glassy carbon electrode was fabricated and used to investigate electrochemical characteristics of hydroquinone, catechol, and resorcinol via cyclic voltammetric analysis under neutral pH conditions. The results imply that the gold nanoparticle/carbon nanotbue modified electrode exhibited a synergistic and excellent electrocatalytic effect of gold nanoparticles and carbon nanotube on the redox behaviors of benzenediols. The reversibility of electrochemical reaction was improved greatly and the peak currents were increased significantly compared with a bare electrode. Good linear relationships were obtained between the oxidation peak currents and the concentrations of catechol and resorcinol. The electrochemical process of catechol was controlled by surface adsorption process, while that of resorcinol was controlled by diffusion process. However, the peak current and the concentration of hydroquinone were not proportional in the whole concentration range, which is because the controlling process of electrochemical reactions was different in the different hydroquinone concentration. Benzenediols could be detected simultaneously at the modified electrode but not at the bare electrode. The stability of the modified electrode was excellent in the benzenediols solutions, which made it possible for the practical application of the modified electrode.


A modified glassy carbon electrode (GCE) compositing multi-walled carbon nanotubes (MWCNTs), Nafion and bismuth film was prepared and applied for the sensitive detection of trace Pb (II). MWCNTs were dispersed into ethanol by ultrasonication in the presence of Nafion and the nanotubes are coated onto the bare GCE. After that, an extra Nafion adhesion agent is added to the electrode. By the in situ plating, a bismuth film was fabricated on the MWCNTs-NA/GCE, making the desired electrode, MWCNTs-NA-Bi/GCE. The modified electrode was characterized by differential pulse anodic stripping voltammetry, scanning electron microscopy, and cyclic voltammetry. A deposition potential of –1.4 V (vs. Ag/AgCl) and a deposition time of 300 s were applied to the working electrode under stirred conditions after optimizing. Nanotubes and Nafion concentrations and pH were carefully optimized to determine trace lead ions by using the electrode as an electrochemical-sensing platform. Nafion effectively increased the stability and adhesivity of the composite film. The MWCNTs-NA-Bi film modified electrode can remarkably increase the anodic peak current of Pb2+. The sensitivity of MWCNTs-NA-Bi/GCE is 4.35 times higher than that of the bare GCE with bismuth film. The prepared electrode showed excellent stability and reproducibility and can be applied for determination of Pb2+ contained wastewater.


2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Koh Sing Ngai ◽  
Wee Tee Tan ◽  
Zulkarnain Zainal ◽  
Ruzniza Mohd Zawawi ◽  
Joon Ching Juan

A rapid, simple, and sensitive method for the electrochemical determination of paracetamol was developed. A single-walled carbon nanotube/nickel (SWCNT/Ni) nanocomposite was prepared and immobilized on a glassy carbon electrode (GCE) surface via mechanical attachment. This paper reports the voltammetry study on the effect of paracetamol concentration, scan rate, pH, and temperature at a SWCNT/Ni-modified electrode in the determination of paracetamol. The characterization of the SWCNT/Ni/GCE was performed by cyclic voltammetry. Variable pressure scanning electron microscopy (VPSEM) and energy dispersive X-ray (EDX) spectrometer were used to examine the surface morphology and elemental profile of the modified electrode, respectively. Cyclic voltammetry showed significant enhancement in peak current for the determination of paracetamol at the SWCNT/Ni-modified electrode. A linear calibration curve was obtained for the paracetamol concentration between 0.05 and 0.50 mM. The SWCNT/Ni/GCE displayed a sensitivity of 64 mA M−1and a detection limit of 1.17 × 10−7 M in paracetamol detection. The proposed electrode can be applied for the determination of paracetamol in real pharmaceutical samples with satisfactory performance. Results indicate that electrodes modified with SWCNT and nickel nanoparticles exhibit better electrocatalytic activity towards paracetamol.


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