Simultaneous determination of ascorbic acid and dopamine at a sol–gel composite electrode

Shankaran, Dhesingh Ravi; Iimura, Ken–ichi; Kato, Takeshi

doi:10.1016/s0925-4005(03)00327-7

Cited by 97 publications

(52 citation statements)

References 29 publications

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“…Using the PLSR2 model developed here, four synthetic mixtures were analyzed (Xval compose by 4 lines and 1501 columns). The multivariate calibration models allow a simultaneous determination of dopamine and ascorbic acid with the relative errors reduced ( These results showed relative errors greater than that obtained by Ravi et al, 17 for which the peaks for the oxidation of ascorbic acid and dopamine were well resolved. However, in our work the multivariate calibration methodology was effective in determining these species, which presented serious problems of the overlapping of oxidations signals.…”

Section: Multivariate Methodologymentioning

confidence: 69%

“…17,19 For example, Ravi et al 17 observed a difference between the two potentials for AA and DA of 250 mV in a mixture, using a sol-gel composite electrode. Selvaraju and Ramaraj 19 found a difference of ca.…”

Section: Multivariate Methodologymentioning

confidence: 99%

“…Furthermore, oxidized DA mediates AA oxidation and the electrode surface can be easily fouled by the product of AA oxidation. In order to distinguish between DA and AA, various methods to prepare electrodes have been developed, as modified carbon nanotubes, 15,16 sol-gel composites, 17 selfassembled monolayers, 18 polymer films, 19 modified carbon pastes 20 and electrochemically pretreated glassy carbon electrodes. 21 Carbon-based electrodes have been used to study the electrochemical oxidation of DA because noble metal electrodes are easily contaminated.…”

Section: Introductionmentioning

confidence: 99%

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Simultaneous voltammetric determination of dopamine and ascorbic acid using multivariate calibration methodology performed on a carbon paste electrode modified by a mer-[RuCl3(dppb)(4-pic)] complex

Santos¹,

Sandrino²,

Moreira³

et al. 2007

J. Braz. Chem. Soc.

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A preparação e caracterização eletroquímica do eletrodo de pasta de carbono (EPC) modificado com o mer- [RuCl 3 (dppb)(4-pic)] (dppb= Ph 2 P(CH 2 ) 4 PPh 2 , 4-pic= CH 3 C 5 H 4 N), denominado Rupic, foi investigada. O sistema EPC/Rupic apresentou apenas um par de picos com potencial médio de 0,28 V vs. Ag/AgCl, o qual foi atribuído ao processo de transferência de elétrons do Ru III /Ru II . Este eletrodo modificado apresentou a propriedade de eletrocatalisar a oxidação da dopamina (DA) e do ácido ascórbico (AA) em 0,35 V e 0,30 V, respectivamente. Como a oxidação dos analitos, AA e DA, ocorreu praticamente no mesmo potencial, não foi possível a distinção dos sinais voltamétricos utilizando-se a voltametria cíclica. Esta limitação foi resolvida empregando-se a Regressão de Mínimos Quadrados Parciais (PLSR), a qual permitiu a determinação de quatro amostras sintéticas, com erros de previsão (RMSEP) de 5,55×10 -5 mol L -1 e 7,48×10 -6 mol L -1 para DA e AA, respectivamente.The preparation and electrochemical characterization of a carbon paste electrode (CPE) modified with mer-[Ru0Cl 3 (dppb)(4-pic)] (dppb=Ph 2 P(CH 2 ) 4 PPh 2 , 4-pic=CH 3 C 5 H 4 N), referred to as Rupic, were investigated. The CPE/Rupic system displayed only one pair of redox peaks, with a midpoint potential at 0.28 V vs. Ag/AgCl, which were ascribed to Ru III /Ru II charge transfer. This modified electrode presented the property of electrocatalysing the oxidation of dopamine (DA) and ascorbic acid (AA) at 0.35 V and 0.30 V vs. Ag/AgCl, respectively. Because the oxidation for both AA and DA practically occurred at the same potential, distinguishing between them was difficult with cyclic voltammetry. This limitation was overcome using Partial Least Square Regression (PLSR), which allowed us, with the optimised models, to determine four synthetic samples with prediction errors (RMSEP) of 5.55×10 -5 mol L -1 and 7.48×10 -6 mol L -1 for DA and AA, respectively. Keywords: carbon paste electrodes, ruthenium complexes, dopamine, ascorbic acid, multivariate calibration methodology IntroductionConsiderable progress has been made over the last few years on chemically modified carbon paste electrodes, having an easier and faster procedure to assemble and renew the paste surfaces, low cost, background currents and possibility to incorporate a series of materials. [1][2][3][4][5] Among the materials that may be used in conjunction with carbon paste are the ruthenium-containing compounds such as oxides, mixed valence compounds and complexes. These Ru-based materials possess electrocatalytic properties, which have been used to modify electrodes for electroanalysis of ascorbic acid, 6,7 L-dopa, 8 glucose, 9 benzylic compounds 10 and dopamine. 11 Dopamine (DA) and ascorbic acid (AA), in particular, are relevant from the biomedical and neurochemical point of view, for their importance to human metabolism. DA is involved in the functioning of the central nervous system, in addition to the cardiovascular, renal and hormonal systems, and plays an important role in ...

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Section: Multivariate Methodologymentioning

confidence: 69%

Section: Multivariate Methodologymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Simultaneous voltammetric determination of dopamine and ascorbic acid using multivariate calibration methodology performed on a carbon paste electrode modified by a mer-[RuCl3(dppb)(4-pic)] complex

Santos¹,

Sandrino²,

Moreira³

et al. 2007

J. Braz. Chem. Soc.

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“…Therefore, the quick determination of dopamine in vitro and in living creatures has attracted considerable attention. [25][26][27][28] This paper proposes an electrochemical procedure employing an innovative, stable inorganic support.…”

Section: Introductionmentioning

confidence: 99%

Adsorption of a copper (II) complex on calcium phosphate intercalated with 4-aminobenzoic acid: synthesis and electrochemical investigation

Silva¹,

Souza²,

Santos³

et al. 2013

Quím. Nova

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Recebido em 14/2/13; aceito em 9/5/13; publicado na web em 17/7/13In this study, the adsorption isotherm of copper (II) on a calcium phosphate host intercalated with 4-aminobenzoic acid in an ethanol solution was investigated. This gave a maximum adsorption capacity of 1.74 mmol g -1 . The material was incorporated into a carbonpaste electrode, and its electrochemical properties were investigated. However, for a dopamine solution, the anodic peak current increased owing to the electrocatalytic oxidation. The electrode presented the same response for at least 150 successive measurements, showing good repeatability. The modified electrode is very stable and reproducible. The electrode sensor was successfully applied for dopamine determination in pharmaceutical preparations.

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“…2 AA has also been used to prevent and treat the common cold, mental illness, infertility and cancer. 3 Moreover, ascorbic acid has also been used clinically in the treatment and prevention of scurvy. 4 Uric acid (2,6,8-trihydroxypurine, UA) is the primary product of purine metabolism in the human body and is formed in liver and tissues during the oxidation of aminopurines.…”

Section: Introductionmentioning

confidence: 99%

Micelle-mediated method for simultaneous determination of ascorbic acid and uric acid by differential pulse voltammetry

Reis¹,

Tarley²,

Kubota³

2008

J. Braz. Chem. Soc.

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O presente trabalho descreve uma metodologia analítica para determinação simultânea de ácido ascórbico (AA) e ácido úrico (AU) por voltametria de pulso diferencial empregando o surfactante catiônico cloreto de cetilpiridínio. Medidas voltamétricas de pulso diferencial realizadas em pH 7,0 revelaram que o meio micelar catiônico permite separar em 282 mV os picos de oxidação de AA e AU na mesma solução, valor suficiente para determinar ambas as espécies simultaneamente. Como em pH 7,0 o AA está mais ionizado que o AU, sua atração eletrostática em direção às micelas catiônicas, formadas sobre a superfície do eletrodo de carbono vítreo, é maior; desta forma, promove a diminuição no sobrepotencial e o aumento na taxa de transferência de elétrons. Foram construídas curvas de calibração para AA e AU na faixa de concentração de 4,70 até 220 µmol L -1 e 0,50 até 110 µmol L -1 . A metodologia proposta foi aplicada para a determinação de AA e AU em amostras de urina humana.The present work describes an analytical methodology for simultaneous determination of ascorbic acid (AA) and uric acid (UA) by differential pulse voltammetry employing the cationic surfactant, cetylpyridinium chloride. Differential pulse voltammetry measurements revealed that the cationic micellar media may separate the oxidation peak potentials of AA and UA present in the same solution by about 282 mV, which is enough to determine both species simultaneously. As in pH 7.0 the AA is more ionized than UA, its electrostatic attraction towards the cationic micelles formed onto the surface of glassy carbon electrode is higher, therefore, promoting a decrease in the overpotential and increasing the electron transfer rate. Calibration curves to AA and UA in the concentration range from 4.70 up to 220 µmol L -1 and 0.50 up to 110 µmol L -1 were built. The proposed methodology was applied for the simultaneous determination of AA and UA in human urine samples.Keywords: uric acid, ascorbic acid, differential pulse voltammetry, cationic surfactant, micelles IntroductionAscorbic acid (AA) and uric acid (UA) coexist in biological fluids such as blood and urine, 1 being in practical medicine, necessary to determine AA and UA simultaneously. Ascorbic acid (a water soluble vitamin C) plays a vital role in processes of oxidation and reduction in the human organism by participating in many metabolic reactions. 2 AA has also been used to prevent and treat the common cold, mental illness, infertility and cancer. 3 Moreover, ascorbic acid has also been used clinically in the treatment and prevention of scurvy. 4 Uric acid (2,6,8-trihydroxypurine, UA) is the primary product of purine metabolism in the human body and is formed in liver and tissues during the oxidation of aminopurines. 5 Its abnormal concentration level in urine and serum are symptoms of several diseases like gout, hyperuricaemia and Lesch-Nyhan syndrome. 6,7 For instance, the concentration of uric acid in the blood of patients suffering from gout increases up to 1 mmol L -1 , which is above the concentration ...

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Simultaneous determination of ascorbic acid and dopamine at a sol–gel composite electrode

Cited by 97 publications

References 29 publications

Simultaneous voltammetric determination of dopamine and ascorbic acid using multivariate calibration methodology performed on a carbon paste electrode modified by a mer-[RuCl3(dppb)(4-pic)] complex

Simultaneous voltammetric determination of dopamine and ascorbic acid using multivariate calibration methodology performed on a carbon paste electrode modified by a mer-[RuCl3(dppb)(4-pic)] complex

Adsorption of a copper (II) complex on calcium phosphate intercalated with 4-aminobenzoic acid: synthesis and electrochemical investigation

Micelle-mediated method for simultaneous determination of ascorbic acid and uric acid by differential pulse voltammetry

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