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Search Results: 1 - 10 of 10465 matches for " glassy carbon electrode "
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Electrochemical Behavior of Chalcone at a Glassy Carbon Electrode and Its Analytical Applications  [PDF]
Keerti M. Naik, Sharanappa T. Nandibewoor
American Journal of Analytical Chemistry (AJAC) , 2012, DOI: 10.4236/ajac.2012.39086
Abstract: A simple and rapid method was developed using cyclic, differential pulse and square wave voltammetric techniques for the determination of trace-level chalcone at a glassy carbon electrode. Chalcone could produce two anodic peaks at about 0.514 V and 1.478 V and a cathodic peak at about -0.689 V. The differential pulse voltammerty presents a good linear response as compared to square wave voltammetry in the range of 0.2 - 10 μM with a detection limit of 0.18 μM. The proposed method was used successfully for its quantitative determination in spiked human plasma and urine as real samples.
Use of Graphene and Cucurbit[7]uril Electrodes for the Determination of Amantadine in Biological Fluids  [PDF]
C. S. H. Domínguez, P. Hernández
American Journal of Analytical Chemistry (AJAC) , 2015, DOI: 10.4236/ajac.2015.67060
Abstract: A differential pulse voltammetry (DPV) method for amantadine (AT) determination is developed. To this end, all the chemical and instrumental variables affecting the determination of amantadine are optimized. These studies have used three types of glassy-carbon electrode, first electrode which has not undergone surface modification or coating, to then modify the working electrode surface with two kinds of suspensions: graphene and graphene-cucurbit[7]uril (CB[7]). From studies of the mechanisms governing the electrochemical response of amantadine, it was concluded that it is an electrochemically system with a diffusive reduction phenomenon. Under optimal conditions and with the appropriate electrode modification, we proceed to study the relation between the peak intensity with the analyte concentration. Thus, we find that when the electrode surface is covered with graphene-CB[7], two linear sections are obtained, the first one in the concentration range of between 0.05 μg·mL﹣1 and 0.75 μg·mL﹣1 ; and the second one between 1.00 μg·mL﹣1 and 6.00 μg·mL﹣1, with Er (%) = 87 and R.S.D. = 0.94% (n = 10 at 0.5 μg·mL﹣1 level). The minimum detectable amount was 15 ng·mL﹣1 while a concentration of 44 ng·mL﹣1 was calculated as determination limit. The optimized method was applied to the determination of amantadine in biological fluids.
Electrochemical Behavior and the Determination of Omeprazole Using Glassy Carbon Electrode
Jin-Long Yan
Journal of Applied Sciences , 2006,
Abstract: The electrochemical behavior of omeprazole on a glassy carbon electrode was investigated by cyclic voltammetry and differential pulse voltammetry. It was found that omeprazole would give a sensitive oxidation peak at +0.74 V in the HAc-NaAc buffer solution (pH 5.10) under the Differential Pulse Voltammetric (DPV) mode. The peak current was linear with the concentration of omeprazole in the range of 1.0~20 mg L-1. Based on which, a DPV method for determination of omeprazole with the detection limit of 0.19 mg L-1 has been developed. The proposed method has been used for determination of omeprazole concentration in omeprazole enteric-coated tablets, the recovery was found to be in the range of 99.3~102%. The mechanism for this electrochemical reaction at the glassy carbon electrode was also discussed in this study.
NITRORADICAL ANION FORMATION FROM NITROFURANTOIN IN CARBON ELECTRODES
MERINO,M.; CARBAJO,J.; NU?EZ-VERGARA,L.J.; SQUELLA,J.A.;
Boletín de la Sociedad Chilena de Química , 2000, DOI: 10.4067/S0366-16442000000100013
Abstract: the electrochemical nitroreduction of nitrofurantoin has been studiedon carbon paste and glassy carbon electrodes. we can observe a monoelectronicreversible couple arno2/arno2.- and anirreversible peak due to the further reduction of nitro radical to thehidroxilamine via three electrons. according to the experimental results, the reduction process shows atypical behavior of an ec mechanism. the k2 obtained values showed that the nitroradical anion was better stabilized on carbon paste electrode
Study of the electrochemical reduction of amoebicide teclozan and its amperometric determination in pharmaceutical formulations
Santos, André L.;Takeuchi, Regina M.;Stradiotto, Nelson R.;Esteves, Ana Paula;Medeiros, Maria José;
Journal of the Brazilian Chemical Society , 2008, DOI: 10.1590/S0103-50532008000600014
Abstract: the electrochemical reduction of amoebicide teclozan (tec) was studied on a glassy carbon electrode in acetonitrile. controlled-potential electrolyses were performed for coulometric and preparative purposes. the electrogenerated products were isolated by liquid-liquid extraction and characterized by 1h nmr. it was observed that tec presents two voltammetric peaks, each one associated with the cleavage of two c-cl bonds. in presence of a proton donor it was observed that the first peak at -1.8 v promotes mainly the reduction of the groups chcl2 to ch2cl and the second one at -2.2 v promotes the reduction of the groups ch2cl to ch3 giving as the sole product the completely dechlorinated tec derivative with yields between 82 and 97%. in addition, a comparative study between the analytical performance of voltammetric techniques and amperometric detection of tec in hydrodynamic conditions was performed. the amperometric detection was more sensitive than all evaluated voltammetric techniques, providing a detection limit of 8.9 × 10-6 mol l-1.
Investigation of Electrochemical Behavior of Hydrazine with Alizarin as a Mediator on Glassy Carbon Electrode
Mohammad Mazloum Ardakani , Mohammad Ali Karimi, Mohammad Mahdi Zare, Sayed Mahdi Mirdehghan
International Journal of Electrochemical Science , 2008,
Abstract: The anodic oxidation of hydrazine has been studied on a glassy carbon electrode by electrocatalytic effect of alizarin as a homogenous mediator at 0.1 M concentration of phosphate buffer (pH=6). Using linear sweep voltammetry study showed that, the catalytic current of this system depends on the concentration of hydrazine. The catalytic peak current obtained, was linearly dependent on the hydrazine concentration in the ranges of 10-800 μM and the detection limit was 4.6 μM by linear sweep voltammetry. The magnitude of the peak current for alizarin increased severely in the presence of hydrazine, and proportional to concentration of hydrazine. The diffusion coefficient of hydrazine was estimated using chronoamperometry. This method also were used for determine the catalytic rate constant at catalytic reaction between alizarin and hydrazine. The experimental results showed that the peak current varied in the presence of different metal cations, but these effects were omitted in the presence of EDTA, while almost all of anions had no effect on the peak current of hydrazine. The importance of the technique is its ability to electrocatalytic determination of hydrazine with alizarin as homogenous electrocatalyst, while it does not need to prepare as for modified electrode. The independency of this method from the interferences, and its ability at removing the effect of most cationic interferences easily are the features of the technique.
Determination of Fluvastatin Sodium by Differential Pulse Voltammetry
Jin-Long Yan
Pakistan Journal of Biological Sciences , 2006,
Abstract: To establish method for the determination of fluvastatin sodium in Loscol capsule, the electrochemical behavior of fluvastatin sodium on a glassy carbon electrode was investigated by cyclic voltammetry, linear sweep voltammetry and differential pulse voltammetry. It was found that fluvastatin sodium would give a sensitive oxidation peak at +0. 64 V in the HAc-NaAc buffer solution (pH 5.10) under the Differential Pulse Voltammetric (DPV) mode. The peak current was linear with the concentration of fluvastatin sodium in the range of 2.0~40 mg L-1. Based on which, a DPV method for determination of fluvastatin sodium with the detection limit of 0.24 mg L-1 has been developed. The proposed method has been used for determination of fluvastatin sodium in the Loscol capsule, the recovery was found to be in the range of 98.0~101.2%. The mechanism for this electrochemical reaction at the glassy carbon electrode was also discussed in this study. The electrochemical analysis method described here enables simple and rapid determination of fluvastatin sodium in real samples.
Diagnosis of Sugarcane White Leaf Disease Using the Highly Sensitive DNA Based Voltammetric Electrochemical Determination  [PDF]
Porntip Wongkaew, Suta Poosittisak
American Journal of Plant Sciences (AJPS) , 2014, DOI: 10.4236/ajps.2014.515240
Abstract:

A simple and highly sensitive analysis by electrochemical voltammetry has been developed for diagnosis of the most destructive crop disease in Thailand known as sugarcane white leaf (SCWL). Determination of the corresponding DNA interaction has been obtained from the voltammetric signals of electroactive redox methylene blue (MB) by means of cyclic and differential pulse voltammetry. In this study, a chitosan-modified glassy carbon electrode (GCE) was created by self-assembly to produce electrostatic platform for effective immobilization of the DNA. Fabrication of SCWL-DNA hybridization detection system was performed by immobilizing the ssDNA probe as a specific sensor onto chitosan-modified GCE. Hybridization of complementary DNA from the real samples could then be detected by its respective MB signal. This fabricated DNA probe sensor was shown to be capable for discriminative identification among the DNAs from SCWL plants, mosaic virus infected sugarcane and healthy sugarcane plants. Relationship between the specific hybridization signal and DNA target concentration was also observed under optimal condition. The detection limit of 4.709 ng/μl with the regression coefficient (R2) of 0.998 and overall RSD of 2.44% were obtained by response curve fit analysis. The actual SCWL-ssDNA immobilization and hybridizing event were subsequently confirmed by an observation under atomic force microscope. Thus these experiments demonstrate the first successful and effective DNA based voltammetric electrochemical determination for a verification of the specific pathogenic infection within plants from the real epidemic field.

Comportamento voltamétrico da redu??o de 2-furfuraldeído em etanol utilizando eletrodo de carbono vítreo
Saczk, Adelir Aparecida;Oliveira, Marcelo Firmino de;Okumura, Leonardo Luiz;Stradiotto, Nelson Ramos;
Eclética Química , 2002, DOI: 10.1590/S0100-46702002000200012
Abstract: this study reports the electrochemical behavior of 2-furfuraldehide reduction in ethanol using glassy carbon electrode, aiming to correlate adequate experimental conditions for determination of this 2-furfuraldehide in fuel ethanol. obtained voltammograms for 2-furfuraldehide in a scan rate of 100mv.s-1 present a cathodic peak current in a potential of -1,45v vs. sce for aqueous medium and -1,71v vs. sce for alcoholic medium, being observed no anodic currents in these reactional media. the relation of ipc with v1/2 showed linear behavior in both media, exhibiting a mass transport controlled by diffusion. the analysis of electrochemical parameters obtained in this work has exhibited an irreversible behavior for the electrodic process. the dependence of cathodic peak current against concentration showed linearity in the interval of 9,5x10-4 to 5,8x10-3 mol l-1 for both media. the sensitivity of method on the aqueous and alcoholic medium was 13,4 and 13,0 (x 10-3) ma mol-1 l respectively. the limits of detection (l.d.) for 2-furfuraldehide, on the aqueous and alcoholic medium was 0,70 e 0,80 (x 10-3) mol l-1 respectively.
Electrochemical behavior of Propranolol and its major metabolites, 4'-hydroxypropranolol and 4'-hydroxypropranolol Sulfate, on glassy carbon electrode
Baranowska, Irena;Koper, Marta;
Journal of the Brazilian Chemical Society , 2011, DOI: 10.1590/S0103-50532011000800025
Abstract: the electrochemical behavior of propranolol (pro) and its major metabolites was studied. voltammetric measurements were made on glassy carbon electrode (gce). all examined compounds were electrochemically oxidized. in all cases, a separation of oxidation peaks was observed, suggesting the possibility of simultaneous electroanalysis of propranolol and its metabolites. the linearity of the calibration curves was obtained for concentrations between 4.22×10-6-1.35×10-4 mol l-1 for pro, 4.00×10-6-4.81×10-5 mol l-1 for 4'-hydroxypropranolol (4'oh ph) and 3.52×10-6-4.22×10-5 mol l-1 for 4'-hydroxypropranolol sulfate (4'oh ps). the described method is rapid and simple, and could be applied to determine the above mentioned compounds in biological samples. the obtained results were verified by ultra-high performance liquid chromatography (ultra hplc) method.
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