Carbon paste electrode modified with copper(II) phosphate immobilized in a polyester resin for voltammetric determination of l -ascorbic acid in pharmaceutical formulations

Teixeira, Marcos F.S.; Ramos, Luiz Antônio; Fatibello‐Filho, Orlando; Cavalheiro, Éder Tadeu Gomes

doi:10.1007/s00216-003-1866-5

Cited by 32 publications

(13 citation statements)

References 43 publications

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“…Cu(II) ions are chemically reduced by ascorbic acid, forming Cu(I) ions that, in the subsequence, are electrochemically oxidized, this gives rise to the electrocatalytic cycle shown in Scheme 1. 22 The use of carbon nanotubes for the synthesis of the electrode material provided greater resistance and greater sensitivity in the simultaneous response of Cu 2+ and Pb…”

Section: +2mentioning

confidence: 99%

An alternative method for the simultaneous determination of copper and lead for quality control of sugar cane spirit using a nanotube-based sensor

Tavares¹,

Okumura²,

Cardoso³

et al. 2012

J. Braz. Chem. Soc.

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Um método eletroanalítico foi desenvolvido para determinação simultânea de íons cobre e chumbo em cachaça empregando eletrodo de pasta de carbono modificado com ácido ascórbico e nanotubos de carbono (CPE-AaCNT). A técnica de voltametria de onda quadrada (SWV) com redissolução anódica foi empregada e otimizada com relação aos seguintes parâmetros: frequência (50 Hz), amplitude (100 mV) e incremento de varredura (9 mV). As curvas analíticas apresentaram intervalo linear de 0,09 a 7,00 mg L -1 para o chumbo e para o cobre. Os limites de detecção foram de 48,5 e 23,9 µg L -1 para o chumbo e o cobre, respectivamente. O método desenvolvido foi aplicado na determinação simultânea de chumbo e cobre em cinco amostras comerciais de cachaça. Os resultados apresentaram-se concordantes com os obtidos por F AAS/GF AAS (espectrometria de absorção atômica com chama/espectrometria de absorção atômica com forno de grafite) e revelaram que CPE-AaCNT podem ser empregados com êxito na quantificação de cobre e chumbo em amostras comerciais de cachaça.The development of an electroanalytical method for simultaneous determination of copper and lead ions in sugar cane spirit (cachaça) using carbon paste electrode modified with ascorbic acid and carbon nanotubes (CPE-AaCNT) is described. Squarewave voltammetry (SWV) with anodic stripping was employed, and this technique was optimized with respect to the following parameters: frequency (50 Hz), amplitude (100 mV) and scan increment (9 mV). The analytical curves were linear in the range from 0.0900 to 7.00 mg L -1 for lead and copper. The limits of detection were 48.5 and 23.9 µg L -1 for lead and copper, respectively. The developed method was applied to the simultaneous determination of copper and lead in five commercial samples of sugar cane spirit. The results were in good agreement with those obtained by F AAS/GF AAS (flame atomic absorption spectrometry/graphite furnace atomic absorption spectrometry) and showed that CPE-AaCNT can be successfully employed in the simultaneous determination of these metals in real sugar cane spirit samples.

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Section: +2mentioning

confidence: 99%

An alternative method for the simultaneous determination of copper and lead for quality control of sugar cane spirit using a nanotube-based sensor

Tavares¹,

Okumura²,

Cardoso³

et al. 2012

J. Braz. Chem. Soc.

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“…These include indirect spectrophotometric methods based on the reduction of compounds such as DCIP [1][2][3][4] , Iron(III) [5][6][7][8][9][10] , the ketone derivatisation method with ophenylenediamine [11][12][13] .Electrochemical [14][15][16][17][18][19] ,fluorimetric [20][21][22][23] ,kinetic 24,25 ,enzymatic 26,27 ,and chemiluminescence [28][29][30][31] methods have also been proposed. These methods have been used to increase the analytical sensitivity for ascorbic acid and some of them have been automated, but specialised equipment's are required for these procedures.…”

Section: Introductionmentioning

confidence: 99%

Colorimetric determination of vitamin C using Fe(II)-5-Chloro-7-iodo-8-hydroxyquinoline complex

2017

JCBSC

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An extractive spectrophotometric procedure based on the complexation of reduced Iron (II) with 5-Chloro-7-iodo-8-hydroxyquinoline (CIHQ) for the estimation of micro amounts of vitamin C is described. The resulting complex is extracted into chloroform to give a reddish brown extract which shows an absorption band at 485 nm. Linear relationship between absorbance and concentration of ascorbic acid is observed up to 0.8 μg ml -1 . Interference studies of different substances including sugars, vitamins and amino acids, metal ions and organic acids were carried out. The utility of the method was tested by analysing some of the marketed products of vitamin C.

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“…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.…”

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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Carbon paste electrode modified with copper(II) phosphate immobilized in a polyester resin for voltammetric determination of l -ascorbic acid in pharmaceutical formulations

Cited by 32 publications

References 43 publications

An alternative method for the simultaneous determination of copper and lead for quality control of sugar cane spirit using a nanotube-based sensor

An alternative method for the simultaneous determination of copper and lead for quality control of sugar cane spirit using a nanotube-based sensor

Colorimetric determination of vitamin C using Fe(II)-5-Chloro-7-iodo-8-hydroxyquinoline complex

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

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