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Segor, Fred; Orata, Duke

doi:10.1023/a:1019038219556

Cited by 9 publications

(8 citation statements)

References 15 publications

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“…Cyclic voltammetry is a versatile electro-analytical technique for the study of electro-active species, and has been labeled 'electrochemical spectroscopy' (Orata and Segor, 1999). Modified electrodes, that is, electrodes on whose surfaces that chemical species has been deliberately immobilized have been used to facilitate electron transfer from bacteria to electrodes (Heinze and Muller, 1998)., as sensors (Guo et al, 2013;Rezaei et al, 2013), catalysts (Rahul et al, 2007) and to provide new methods of analysis (Nada et al, 2007;Kuralay et al, 2013;Oukil et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

“…It has also been used to remove pollutants from waste waters (Jovic-Jovicic et al, 2013;Zhang et al, 2013;Shi et al, 2013;Reitzel et al, 2013). Kenyan bentonite has been used, with good results, to modify electrodes for electrodeposition of polyaniline (Orata and Segor, 1999). However, the same has not been used to monitor other species like cations in aqueous systems.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of Kenyan bentonite in adsorption of some heavy metals in aqueous systems using cyclic voltammetric techniques

Mbui¹,

Orata²,

Jackson³

et al. 2014

Int. J. Phys. Sci.

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Potential application of Kenyan bentonite for adsorption of iron, cobalt, copper, nickel and zinc and for analysis of electroactive species in water from a polluted water course using a 3-electrode potentiostat and cyclic voltammetry was studied. Polished carbon graphite electrodes were used either bare or modified with Kenyan bentonite using an electrochemically inert adhesive to a thickness of about 0.8 mm. These were used to prepare calibration curves of iron, cobalt, copper, nickel and zinc by plotting cyclic voltammograms of the ions at different concentrations and using 0.1 M sulphuric acid as supporting electrolyte. The slopes of the curves from bentonite-modified electrodes were observed to be higher than those obtained from bare carbon electrodes by a factor of between 1.7 and 24, implying that bentonite enhanced electron transfer kinetics of the metal ions. It was also observed that the magnitude of the ratio depended on the proximity of the element to either filled or half-filled 3d orbitals, which implied that a chemical reaction may have taken place between the bentonite and the ions (chemisorption). Carbon graphite electrodes were modified with bentonite that had been soaked in water samples from a polluted water course at a ratio of 1:1 w/w. The cyclic voltammograms showed clear oxidative and reductive peaks indicating that electroactive species that previously could not be detected on the potentiostat were pre-concentrated on the bentonite and could thus be detected. Thus Kenyan bentonite is observed to chemically adsorb zinc, cobalt, copper, nickel and iron species in aqueous solution and can be used to monitor electroactive pollutants in aqueous systems using electroanalytical techniques.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Investigation of Kenyan bentonite in adsorption of some heavy metals in aqueous systems using cyclic voltammetric techniques

Mbui¹,

Orata²,

Jackson³

et al. 2014

Int. J. Phys. Sci.

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“…T 4 has been determined in urine by cathodic striping square wave voltammetry at the hanging mercury drop electrode and a low detection limit of 2.71 ng/mL was achived [20]. Chemically modified electrodes were initially used by D. Orarat and F. Seger [21]. Later on, Hus group utilized modified carbon paste and glassy carbon electrodes for determination of T 4 [22][23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Electrochemistry of Levo‐Thyroxin on Edge‐Plane Pyrolytic Graphite Electrode: Application to Sensitive Analytical Determinations

Khafaji¹,

Shahrokhian²,

Ghalkhani³

2011

Electroanalysis

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The electrochemical response of sodium levo-thyroxin (T 4 ) at the surface of an edge plane pyrolytic graphite (EPPG) electrode is investigated using cyclic voltammetric technique in the presence of 0.1 M HCl as supporting electrolyte. T 4 underwent totally irreversible oxidation at this system and a well-defined peak at 821 mV was obtained. Compared to the signals obtained in the optimized conditions at bare glassy carbon and carbon paste electrodes, the oxidation current of T 4 at an EPPG electrode was greatly enhanced. The electrochemical process of T 4 was explored and the experimental conditions were optimized. The oxidation peak current represented a linear dependence on T 4 concentration from 0.01 to 10 mM. The detection limit of 3 nM (S/N = 3) was obtained for 250 s accumulation at 0.3 V. Determination of T 4 in a synthetic serum sample demonstrated that this sensor has good selectivity and high sensitivity.

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“…With respect to the electrical properties of nanoparticles and of all kind of arrangements constructed from nanoparticles, the most important property is the amount of energy needed to add one extra electron to an initially uncharged particle. Chemically modified electrodes (CMEs) have played an important role in studies of electrocatalysis, 8 electron transfer kinetics, 9 membrane barriers, 10 electro-organic syntheses, 11 etc. 7 The chemical modification of electrodes with a suitable reagent has been widely used for analytical applications.…”

Section: Introductionmentioning

confidence: 99%

Fabrication and characterization of molybdenum(VI)complex-TiO2 nanoparticles modified electrode for the electrocatalytic determination of L-cysteine

Mazloum-Ardakani

Beitollahi

Taleat

et al. 2011

JSCS

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A novel voltammetric sensor for the determination of L-cysteine (L-Cys) was fabricated based on a TiO 2 nanoparticles/bis[bis(salicylidene-1,4--phenylenediamine) molybdenum(VI)] carbon paste electrode. The electrochemical behavior of the sensor was investigated in detail by cyclic voltammetry. The apparent electron transfer rate constant (k s ) and charge transfer coefficient (α) of the TiO 2 nanoparticles/molybdenum(VI) complex/carbon paste electrode (CPE) were also determined by cyclic voltammetry and found to be about 4.53 s -1 and 0.54, respectively. The sensor displayed good electrocatalytic activity towards the oxidation of L-Cys. The peak potential for the oxidation of L-Cys was lowered by at least 130 mV compared with that obtained at an unmodified CPE. Under optimal conditions, the linear range spans L-Cys concentrations from 1.5×10 -6 to 1.2×10 -3 M and the detection limit was 0.70±0.01 µM at a signal-to-noise ratio of 2. In addition, the sensor showed good stability and reproducibility.

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Untitled

Cited by 9 publications

References 15 publications

Investigation of Kenyan bentonite in adsorption of some heavy metals in aqueous systems using cyclic voltammetric techniques

Investigation of Kenyan bentonite in adsorption of some heavy metals in aqueous systems using cyclic voltammetric techniques

Electrochemistry of Levo‐Thyroxin on Edge‐Plane Pyrolytic Graphite Electrode: Application to Sensitive Analytical Determinations

Fabrication and characterization of molybdenum(VI)complex-TiO2 nanoparticles modified electrode for the electrocatalytic determination of L-cysteine

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