A multicommuted flow-system for spectrophotometric determination of tannin exploiting the Cu(I)/BCA complex formation

Moya, Horácio Dorigan; Dantoni, Patricia; Rocha, Fábio R.P.; Coichev, Nina

doi:10.1016/j.microc.2007.08.006

Cited by 25 publications

(32 citation statements)

References 11 publications

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“…24 In addition, a NH 4 OH solution was used as carrier to avoid solid deposition in the analytical path. This strategy was previously employed in the flow systems for tannin 23 and uric acid 24 determinations, and successfully overcame this drawback. In this work, the baseline drift was evaluated through 100 measurements using different NH 4 OH concentrations.…”

Section: System Optimizationmentioning

confidence: 99%

“…The procedure was based on the redox reaction between Cu(II) and captopril, followed by quantification of Cu(I) ions by spectrophotometry in the presence of 4,4'-dicarboxy-2,2'-bichinoline (BCA). Previous works exploited this reaction for the determination of proteins in biological materials, 21,22 tannins in beverages 23 and uric acid in urine. 24 …”

Section: Introductionmentioning

confidence: 99%

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A multicommuted flow system for dissolution studies of Captopril in pharmaceutical preparations

Sanchez

Rocha

Melchert

et al. 2011

J. Braz. Chem. Soc.

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Um procedimento analítico em sistema de análises em fluxo com multicomutação é proposto para a determinação de captopril e construção de curvas de dissolução de medicamentos. O método é baseado na reação do fármaco com Cu(II), com posterior complexação de Cu(I) com 4,4'-dicarboxi-2,2'-biquinolina (BQA) e detecção espectrofotométrica. Foi observada resposta linear entre 25 e 300 μmol L -1 captopril, com limite de detecção de 7 μmol L -1 (99,7% de confiança). O coeficiente de variação (n = 20) e a frequência de amostragem foram 2,2% e 47 determinações por hora, respectivamente, com consumo de 290 μg de BQA e geração de 3,6 mL de resíduo por determinação. Os resultados para 7 amostras de preparações farmacêuticas concordaram com os obtidos pelo procedimento volumétrico de referência com 95% de confiança. Perfis de dissolução obtidos com um aparato construído no laboratório foram concordantes com os relatados na literatura, com coeficiente de variação de 1,8% para três replicatas do produto de referência.A flow-based analytical procedure exploiting multicommutation is proposed for captopril determination and the construction of dissolution curves. The procedure is based on the redox reaction between Cu(II) and the drug with the subsequent complexation of Cu(I) with 4,4'-dicarboxy-2,2'-bichinoline (BCA) and spectrophotometric detection. A linear response was observed between 25 and 300 μmol L -1 captopril and the detection limit was estimated as 7 μmol L -1 (99.7% confidence level). The coefficient of variation (n = 20) and sampling rate were 2.2% and 47 determinations per hour, respectively, consuming 290 μg of BCA and generating 3.6 mL of waste per determination. The results for seven pharmaceutical samples agreed with those obtained by the reference volumetric procedure at the 95% confidence level. The dissolution profiles attained with a lab-made dissolution apparatus agreed with those reported in the literature, with a coefficient of variation of 1.8% for three replicates of the reference product.

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Section: System Optimizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A multicommuted flow system for dissolution studies of Captopril in pharmaceutical preparations

Sanchez

Rocha

Melchert

et al. 2011

J. Braz. Chem. Soc.

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“…Usando somente água deionizada como transportador, foi observada deriva de linha base, causada pelo depósito do sólido verde de Cu(BQA) na cela de fluxo. Hidróxido de amônio foi adicionado ao transportador para melhorar a limpeza da cela de fluxo, 13 3 ) e amônia. Embora este ligante esteja presente em baixa concentração em solução de acetato de amônio em pH 7,0, a elevada constante de formação favorece a dissolução do sólido CuBQA.…”

Section: Otimização Das Variáveisunclassified

“…Apesar de resultados distintos terem sido obtidos para cada fármaco, a melhor resposta, considerando o sinal analítico e a reprodutibilidade, foi obtida em pH 7,0, no qual o sistema tampão apresenta sua maior capacidade tamponante. Este pH coincide com o empregado em estudos anteriores, [13][14][15][16][17] exceto no caso da determinação de proteínas. 12 O comprimento do reator afeta tanto o tempo de residência, quanto a dispersão da amostra.…”

Section: Otimização Das Variáveisunclassified

Sistema de análises em fluxo polivalente para a determinação espectrofotométrica de fármacos

Schmidt¹,

Melchert²,

Rocha³

2011

Quím. Nova

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Recebido em 17/12/10; aceito em 3/3/11; publicado na web em 5/5/11 A POLIVALENT FLOW SYSTEM FOR THE SPECTROPHOTOMETRIC DETERMINATION OF PHARMACEUTICALS. A flow system based on the sandwich technique is proposed for the sequential determination of ascorbic acid, dipyrone, acetylcysteine, captopril and paracetamol. The procedure is based on the reduction of Cu(II) by the analytes followed by the spectrophotometric measurement of the complex of Cu(I) with 2,2′-biquinoline 4,4′-dicarboxylic acid. Linear responses were achieved in the μmol L -1 range, with coefficients of variation better than 1.7%. Sampling rate was estimated as 60 determinations per hour, consuming 230 μg of BQA and generating 2.5 mL of waste per determination. Results for commercial samples agreed with those obtained by procedures recommended by the American and European pharmacopeias at the 95% confidence level.

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“…68 In other approach, a multicommuted flow system was employed for determination of tannin in tea and wine samples, exploiting Cu(II) reduction and complex formation with 4,4′-dicarboxy-2,2′-biquinoline. 69 Another popular beverage in Brazil and world-wide consumed is obtained from fermentation and distillation of sugar-cane, popularly called as cachaça. One of the focuses is the determination of polycyclic aromatic hydrocarbons, PHAs, because of their potential effects on human health.…”

mentioning

confidence: 99%

Analytical chemistry in Brazil: healthy and growing

Rocha

Pereira-Filho²,

Nóbrega³

2009

J. Braz. Chem. Soc.

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A química brasileira está crescendo rapidamente, sendo um dos principais alicerces para o contínuo desenvolvimento do país. Inspirados no 15º Encontro Nacional de Química Analítica, ENQA, com um número recorde de participantes e comunicações, decidiu-se revisar os recentes desenvolvimentos em química analítica no Brasil. Foram escolhidas as mesmas áreas de aplicação adotadas para a organização temática do ENQA e selecionados artigos publicados por autores brasileiros em 7 periódicos de ampla penetração na área. Os dois periódicos científicos editados pela Sociedade Brasileira de Química também foram pesquisados. Esta revisão não é exaustiva, porém os trabalhos selecionados após 2008 mostram uma significativa visão geral da área. Pode-se concluir que a química analítica brasileira está saudável, em crescimento e certamente atenderá as demandas do país como uma potência emergida.Chemical sciences in Brazil are growing fast and being one of the main supports for the continuous development of the country. Inspired on the 15 th Brazilian Meeting on Analytical Chemistry, ENQA, with a record number of participants and communications, we have decided to review recent developments in analytical chemistry in Brazil. We have chosen the same application areas used for the thematic organization of the ENQA and have searched papers published by Brazilian authors in 7 major and general journals in analytical chemistry. The two scientific journals published by the Brazilian Chemical Society were also searched. This review is not comprehensive, but the selected papers published after 2008 shown an impressive overview of the area. We may conclude that analytical chemistry is healthy and growing in Brazilian scenario and certainly will attend the demands of Brazil as an emerged power.

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A multicommuted flow-system for spectrophotometric determination of tannin exploiting the Cu(I)/BCA complex formation

Cited by 25 publications

References 11 publications

A multicommuted flow system for dissolution studies of Captopril in pharmaceutical preparations

A multicommuted flow system for dissolution studies of Captopril in pharmaceutical preparations

Sistema de análises em fluxo polivalente para a determinação espectrofotométrica de fármacos

Analytical chemistry in Brazil: healthy and growing

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