Voltametria de onda quadrada. Primeira parte: aspectos teóricos

Souza, Djenaine De; Machado, Sérgio Antônio Spínola; Avaca, Luís Alberto

doi:10.1590/s0100-40422003000100015

Cited by 144 publications

(102 citation statements)

References 26 publications

(35 reference statements)

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“…24 Insights on the mechanism were also obtained using square wave voltammetry. 25 For equivalent concentrations of sibutramine-HCl, SWV produced peak current intensities about two times the one achieved using DPV as indicated by the ratio between the angular coefficient of the analytical curves obtained by SWV (m SWV = 4.8) and by DPV (m DPV = 2.1). This is characteristic of reversible systems with adsorption of the product on the electrode.…”

Section: Mechanism Insights Based On Cyclic Voltammetry Square-wave mentioning

confidence: 93%

Voltammetric determination of sibutramine in beverages and in pharmaceutical formulations

Carvalho¹,

Silva²,

Cunha³

et al. 2012

Quím. Nova

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Recebido em 6/10/11; aceito em 30/11/11; publicado na web em 23/1/12 A simple and sensitive method has been proposed for the determination of sibutramine-HCl in energy drinks, green tea and pharmaceutical formulations using differential pulse voltammetry performed on a hanging mercury drop electrode. In the chosen experimental condition (Mcllvaine pH 4.0 buffer, 50 mV pulse amplitude and 40 mV s -1 scan velocity), sibutramine-HCl presented a reversible behavior and a peak maximum at -80 mV. Detection limit was 0.4 mg L -1 and the working linear range extended up to 33.3 mg L -1 (r = 0.99). Analysis of real and fortified samples enabled recoveries between 91 and 102%. The electroanalytical method was compared with a HPLC method which indicated it accuracy.

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Section: Mechanism Insights Based On Cyclic Voltammetry Square-wave mentioning

confidence: 93%

Voltammetric determination of sibutramine in beverages and in pharmaceutical formulations

Carvalho¹,

Silva²,

Cunha³

et al. 2012

Quím. Nova

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“…Machado, Avacca and coworkers [137][138][139] have reviewed some theoretical aspects and studied the utilization of Pt, Co, or Ni-Co microelectrodes (UME) to characterize copper electrocrystallization and hydrogen evolution. Mori and Bertotti 140 have investigated the chemical reaction between nitrite and iodide by using microelectrodes and Cavalheiro and co-workers 141 have shown the application of nanostructured carbon fiber disk microelectrodes for determination of adenosine and uric acid in physiological buffers.…”

Section: Amperometric Biosensorsmentioning

confidence: 99%

Electrochemical sensors: a powerful tool in analytical chemistry

Stradiotto¹,

Yamanaka²,

Zanoni³

2003

J. Braz. Chem. Soc.

318

154

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Sensores potenciométricos, amperométricos e condutométricos são sensores eletroquímicos com imensa aplicação nas áreas de meio ambiente, indústria e análises clínicas. O presente trabalho apresenta uma revisão generalizada dos aspectos fundamentais, os desenvolvimento e a contribuição destes sensores na área de química analítica, e reporta alguns aspectos relevantes dos avanços na área de sensores eletroquímicos no Brasil.Potentiometric, amperometric and conductometric electrochemical sensors have found a number of interesting applications in the areas of environmental, industrial, and clinical analyses. This review presents a general overview of the three main types of electrochemical sensors, describing fundamental aspects, developments and their contribution to the area of analytical chemistry, relating relevant aspects of the development of electrochemical sensors in Brazil.

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“…The technique employed was square wave voltammetry (SWV), 30 and the SWV characteristic parameters were: step potential (ΔE s ) 0.002 V, frequency (f) 100 Hz and pulse amplitude (ΔE SW ) 0.050 V.…”

Section: Analytical Curvementioning

confidence: 99%

Electrochemical determination of oncocalyxone A using an iron-phthalocyanine/iron-porphyrin modified glassy carbon electrode

Costa¹,

Souza²,

Luz³

et al. 2008

J. Braz. Chem. Soc.

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Descreve-se, no presente trabalho, o desenvolvimento de um sensor voltamétrico altamente sensível para a oncocalixona A, utilizando-se eletrodo de carbono vítreo modificado com uma bicamada de ftalocianina tetrassulfonada de ferro(II) (FeTSPc) e tetra-(N-metil-4-piridil)-porfirina de ferro(III) (FeT 4 MPyP). O eletrodo modificado apresentou alta atividade catalítica e estabilidade em relação à redução da oncocalixona, proporcionando deslocamento anódico de ca. de 30 mV e amplificação da corrente de pico, em relação a iguais parâmetros obtidos em eletrodo de carbono vítreo não modificado. Um ampla faixa linear de resposta entre 0.005-1.2 µmol L -1 , com sensibilidade de 8.11 µA L µmol -1 e limites de detecção (LOD) e quantificação (LOQ) de 1.5 e 5 nmol L -1 foram obtidos, com o uso desse sensor.The development of a highly sensitive voltammetric sensor for oncocalyxone A using a glassy carbon electrode modified with a bilayer iron(II) tetrasulfonated phthalocyanine (FeTSPc) and iron(III) tetra-(N-methyl-4-pyridyl)-porphyrin (FeT 4 MPyP) is described. The modified electrode showed high catalytic activity and stability for the oncocalyxone A reduction, provoking the anodic shift of the reduction peak potentials of ca. 30 mV and presenting much higher peak currents than those obtained on the bare GC electrode. A wide linear response range between 0.005-1.2 µmol L -1 , with a sensitivity of 8.11 µA L µmol -1 and limits of detection (LOD) and quantification (LOQ) of 1.5 and 5 nmol L -1 were obtained with this sensor.Keywords: voltammetric sensor, oncocalyxone, quinone, chemically modified electrodes, catalysis IntroductionPlants are repositories for bioactive organic molecules. Several classes of natural compounds are pharmacologically active ingredients and serve as drugs and/or leads for drug developments. Among them, quinones, ubiquitous secondary metabolites, play essential roles, mainly in the biochemistry of energy production, serving as vital links in the electron transport. 1 They form an important class of toxic metabolites and paradoxically, can be either, potentially carcinogenic or effective anticancer agents. The cytotoxic activity of quinones can often be correlated to their chemical behavior. The striking feature of quinone chemistry is the ease reduction and therefore their ability to act as oxidizing or dehydrogenating agents, the driving force being the formation of a fully aromatic system. [2][3][4][5] Auxemma oncocalyx Taub. is a native Brazilian tree, characteristic of the xerophytic vegetation present in the northeastern region. It is commonly called "pau branco." The chemical investigation of A. oncocalyx heartwood extracts resulted in the isolation and characterization of several unusual terpenoid quinones and hydroquinones of C 16 framework. 6-9 These secondary metabolites seem to be typical of the genus and, interestingly, were isolated in a homolog series differing in their degree of oxidation, oxygenation (ether or alcohol), rearrangement and intramolecular cyclization of the terpenoid side ...

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Voltametria de onda quadrada. Primeira parte: aspectos teóricos

Cited by 144 publications

References 26 publications

Voltammetric determination of sibutramine in beverages and in pharmaceutical formulations

Voltammetric determination of sibutramine in beverages and in pharmaceutical formulations

Electrochemical sensors: a powerful tool in analytical chemistry

Electrochemical determination of oncocalyxone A using an iron-phthalocyanine/iron-porphyrin modified glassy carbon electrode

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