scholarly journals Electrochemical determination of ascorbic acid at p-phenylenediamine film-holes modified glassy carbon electrode

2015 ◽  
Vol 80 (9) ◽  
pp. 1161-1175 ◽  
Author(s):  
Bikila Olana ◽  
Shimeles Kitte ◽  
Tesfaye Soreta
Keyword(s):  
Ascorbic Acid ◽  
Detection Limit ◽  
Glassy Carbon Electrode ◽  
Modified Electrode ◽  
Glassy Carbon ◽  
Linear Response ◽  
Modified Electrodes ◽  
Electrochemical Determination ◽  
Carbon Electrode

In this work the determination of ascorbic acid (AA) at glassy carbon electrode (GCE) modified with a perforated film produced by reduction of diazonium generated in situ from p-phenylenediamine (PD) is reported. Holes were intentionally created in the modifier film by stripping a pre-deposited gold nanoparticles. The modified electrodes were electrochemically characterized by common redox probes: hydroquinone, ferrocyanide and hexamineruthenium(III). The cyclic voltammetric and amperometric response of AA using the modified electrodes was compared with that of bare GCE. The bare GCE showed a linear response to AA in the concentration range of 5 mM to 45 mM with detection limit of 1.656 mM and the modified GCE showed a linear response to AA in the concentration range of 5 ?M to 45 ?M with detection limit of 0.123 ?M. The effect of potential intereferents on amperometric signal of AA at the modified GCE was examined and found to be minimal. The inter-electrode reproducibility, stability, and accuracy were determined. The modified electrode showed excellent inter-electrode reproducibility, accuracy and stability. The modified electrode reported is a promising candidate for use in electroanalysis of AA.

scholarly journals Electrochemical Determination of Dopamine on a Glassy Carbon Electrode Modified by Using Nanostructure Ruthenium Oxide Hexacyanoferrate/Ruthenium Hexacyanoferrate Thin Film

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Reza Karimi Shervedani ◽  
Hossein Ali Alinajafi-Najafabadi
Keyword(s):  
Ascorbic Acid ◽  
Detection Limit ◽  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Ruthenium Oxide ◽  
Electrochemical Determination ◽  
Human Blood Plasma ◽  
Carbon Electrode ◽  
Oxidation Potentials

Application of mixed ruthenium oxide hexacyanoferrate/ruthenium hexacyanoferrate glassy carbon electrode for electrochemical determination of dopamine (DA) is described for the first time. The overlapped voltammetric oxidation potentials of ascorbic acid (AA) and DA are separated and shifted to more facile direction, +170 and +320 mV versus Ag/AgCl, respectively. Voltammetric response of the electrode toward the DA showed a dynamic calibration curve with two linear parts, from 0.50 to 10.00 μM and 25.00 to 550.00 μM DA, and a detection limit of 0.195 μM. The sensitivity (0.2917 μA/μM) and detection limit (0.195×10−7 μMDA) of this electrode are 21 times higher and 11.5 times lower than those found in our previous paper. The sensor response of 9.95 μMDA was not affected by 5.0 mM of glucose, 4.5 mM of fructose, 0.58 mM of sucrose, 0.28 mM of cystine, 0.25 mM of ascorbic acid, 79.60 μM of cysteine, and 49.70 μM of uric acid and urea. The fabricated sensor was successfully tested for determination of DA in injection medicine and human blood plasma samples.

scholarly journals Differential Electroanalysis of Dopamine in the Presence of a Large Excess of Ascorbic Acid at a Nickel Oxide Nanoparticle-Modified Glassy Carbon Electrode

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Zahrah T. Althagafi ◽  
Jalal T. Althakafy ◽  
Badriah A. Al Jahdaly ◽  
Mohamed I. Awad
Keyword(s):  
Ascorbic Acid ◽  
Nickel Oxide ◽  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Electrochemical Determination ◽  
Carbon Electrode ◽  
Large Excess ◽  
Nickel Oxide Nanoparticle ◽  
Oxide Nanoparticle

Electrochemical determination of dopamine (DA) in the presence of a large excess of ascorbic acid (AA) in their coexistence at a nickel oxide nanoparticle-modified preoxidized glassy carbon electrode (GCox/nano-NiOx) is achieved. The GCox/nano-NiOx electrode is prepared by electrodeposition of nickel nanoparticles (nano-Ni) onto an electrochemically activated glassy carbon (GC) electrode, and the thus prepared nano-Ni were subjected to electrochemical oxidation in alkaline medium for the formation of nickel oxide (NiOx). Modified electrodes were electrochemically and morphologically characterized. The effect of loading level of nickel was investigated by changing the number of potential cycles for the deposition of nano-Ni, i.e., 1, 2, 5, and 10 potential cycles, in the potential range from 0 to -1.0 V vs. SCE. Also, the experimental and instrumental parameters were optimized. Experimental results showed that the modified electrode differentiates well the oxidation peaks of DA and AA enabling the electrochemical determination of DA in the presence of a large excess of AA. Remarkably, it is found that the oxidation current of DA is 2 times larger than that of AA even the concentration of AA is about 5 times larger than that of DA. The LOD and LOQ of DA were calculated and were found to equal 0.69 and 2.3 mM, respectively. This offers the advantage of simple and selective detection of DA free of the interference of AA in real samples.

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