Investigations on the Reduction of Molecular Oxygen on Polyphenol Oxidase-Modified Electrode

2005 ◽  
Vol 70 (3) ◽  
pp. 305-312 ◽  
Author(s):  
Hui Jiang ◽  
Chun-Hua Shi ◽  
Yong-Shu Xie ◽  
Qing-Liang Liu
Keyword(s):  
Polyphenol Oxidase ◽  
Transfer Process ◽  
Square Wave Voltammetry ◽  
Carbon Electrode ◽  
Modified Glassy Carbon Electrode ◽  
Cathodic Peak ◽  
Wave Voltammetry ◽  
Nicotiana Tobacum ◽  
Optimum Salt Concentration ◽  
Proton Transfer Process

Polyphenol oxidase (PPO, E.C.1.10.3.1) from Nicotiana tobacum, PPO II, shows a different behavior from that of PPOs from other sources. A one-electron oxygen reduction on PPO II - Nafion modified glassy carbon electrode surface has been observed by square-wave voltammetry. The cathodic peak has been found to be proportional to the concentration of dissolved oxygen. The optimum salt concentration was 0.2 mol/l. The study of its dependence on pH (4-9) indicates that the reduction of oxygen is accompanied by a one-proton-transfer process. Temperature shows little influence on the cathodic peak. The electrode storage has also been studied to evaluate its stability.

Electrochemical Aptasensor for L-Histidine Detection via Self-Cleavage of DNAzymes and Amplification of End-Truncated Elongated Tetrahexaheral Gold Nanocrystals

2012 ◽  
Vol 485 ◽  
pp. 213-216 ◽  
Author(s):  
Zheng Bo Chen ◽  
Xiao Jiao Mu ◽  
Jing Li ◽  
Li Dong Li ◽  
Lin Guo
Keyword(s):  
Amino Acids ◽  
Electron Transfer ◽  
Glassy Carbon ◽  
Square Wave Voltammetry ◽  
High Specificity ◽  
Carbon Electrode ◽  
Electrochemical Aptasensor ◽  
Modified Glassy Carbon Electrode ◽  
Gold Nanocrystals ◽  
Wave Voltammetry

A sensitive aptamer-based signal-on sensor for real-time detection of L-histidine via self-cleavage of DNAzymes and amplification of elongated tetrahexaheral gold nanocrystals (end-truncated-ETHH-Au-NCs) is presented. The introduction of target L-histidine induced self-cleavage of DNAzymes on the end-truncated-ETHH-Au-NCs modified glassy carbon electrode (GCE) into the solution. The resulting change in electron transfer efficiency is readily measured by square wave voltammetry (SWV) at target L-histidine concentrations as low as 0.1 pM, the increase in the SWV peak current is linear with the concentration of L-histidine in the range from 0.1 pM to 0.1 μM. The fabricated aptasensor shows a high specificity for L-histidine which is not affected by the coexistence of other amino acids, and an excellent enantio-selectivity toward L-histidine was achieved.

scholarly journals Electrochemical Detection of Phenanthrene Using Nickel Oxide Doped PANI Nanofiber Based Modified Electrodes

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Omolola E. Fayemi ◽  
Abolanle S. Adekunle ◽  
Eno E. Ebenso
Keyword(s):  
Nickel Oxide ◽  
Square Wave Voltammetry ◽  
Modified Electrodes ◽  
Oxidation Potential ◽  
Current Response ◽  
Modified Glassy Carbon Electrode ◽  
Square Wave ◽  
Wave Voltammetry ◽  
Doped Polyaniline ◽  
Uv Visible

A nickel oxide doped polyaniline nanofibers (PANI-NiO) based electrochemical sensor was constructed for detection of phenanthrene. Successful synthesis of PANI-NiO nanocomposite was confirmed with techniques such as SEM, XRD, EDX, FTIR, and UV-visible spectroscopy. The electrocatalytic oxidation of phenanthrene on PANI-NiO on modified glassy carbon electrode (GCE-PANI-NiO) was studied using cyclic voltammetry, square wave voltammetry, and impedance spectroscopy and discussed. Results showed that detection of phenanthrene was enhanced by the nanostructure of PANI-NiO film. The square wave voltammetry analysis shows a very low detection limit of 0.732 pM for phenanthrene with the linear range of 7.6 pM–1.4 × 10−11 M. The Tafel value of 227 mVdec−1suggests adsorption of phenanthrene oxidation intermediates on the GCE-PANI-NiO electrode. The GCE-PANI-NiO modified electrodes gave better performance towards phenanthrene in terms of current response, oxidation potential, current recovery, stability, and resistance to electrode fouling effects.

Adsorptive stripping voltammetric determination of dicyclomine hydrochloride at a glassy carbon electrode modified with silver decorated Fe3O4nanocubes in pharmaceutical and biological samples

2018 ◽  
Vol 10 (12) ◽  
pp. 1441-1451 ◽  
Author(s):  
Chaitali R. Rawool ◽  
Anuja S. Rajpurohit ◽  
Ninad S. Punde ◽  
Ashwini K. Srivastava
Keyword(s):  
Electrochemical Sensor ◽  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Biological Samples ◽  
Square Wave Voltammetry ◽  
Synthesis Process ◽  
Carbon Electrode ◽  
Square Wave ◽  
Wave Voltammetry

Synthesis process of Fe3O4/Ag nanocomposite followed by its fabrication as an electrochemical sensor for determination of DcCl using adsorptive stripping square wave voltammetry.

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