Development of an on-line preconcentration system for zinc determination in biological samples

Dutra, Rosilene Linhares; Maltez, Heloísa França; Carasek, Eduardo

doi:10.1016/j.talanta.2005.10.019

Cited by 52 publications

(40 citation statements)

References 22 publications

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“…Several researchers have applied these techniques to optimize different process parameters (VANOT et al, 2002;DUTRA;MALTEZ;CARASEK, 2006;IMANDI et al, 2007).…”

Section: Doehlert Experimental Design -Yeast Cells Lysismentioning

confidence: 99%

Application of Doehlert experimental design in the optimization of experimental variables for the Pseudozyma sp. (CCMB 306) and Pseudozyma sp. (CCMB 300) cell lysis

et al. 2012

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Application of Doehlert experimental design in the optimization of experimental variables for the Pseudozyma sp. (CCMB 306) and Pseudozyma sp. (CCMB 300) cell lysis Aplicação do modelo Doehlert na otimização das variáveis experimentais para a lise de Pseudozyma sp. (CCMB 306) e Pseudozyma sp. (CCMB 300)Amanda Reges de SENA 1,3 , Gildomar Lima VALASQUES JÚNIOR 1,2 , Ingara Keisle São Paulo BARRETTO 1 , Sandra Aparecida ASSIS 1 * IntroductionThe cell wall of yeast is basically made of glucan and mannan-protein. Lytic enzymes such as chitinases, proteases and β-1,3-glucanases are usually necessary. There are numerous applications for biotechnologies: preparation of protoplasts, extraction of pigments, mass treatment of residual yeast cell fermentation industries for preparation of animal feed, in studies of the mechanism of cell wall synthesis for control of pathogenic yeast, etc. (HUNTER;ASENJO, 1988;SATO, 2005;SALAZAR; ASENJO, 2007).These enzymes are capable of lysing the cell wall of Saccharomyces cereviseae, Candida sp. and other genera of yeasts, which extends their use allowing the selective manufacture of products, regardless of scale, and can be performed under temperature and pH conditions that do not involve the denaturation of cellular products of interest (FLEURI; SATO, 2005). Mathematical models have been increasingly used to help explain responses of biochemical reactions. This technique is often used for optimization and/or verification of the influence of medium components and cultivation parameters for enzyme production (FLEURI; SATO, 2008).The production and optimization of the parameters that affect the enzymatic synthesis should always be investigated because the optimal conditions vary among different organisms and different enzymes (BRAVO et al., 2000). In many cases, the interaction of parameters that influence fermentation processes can be evaluated with a reduced number of tests using an experimental design (THÉODORE; PANDA, 1995). Several experimental design models could be used to reduce the number of experiments under different conditions. Among them are the Plackett-Burman, Doehlert, Central Composite, and Box-Behnken (LI et al., 2007).The choice of Doehlert design is justified by a number of advantages such as (1) its spherical experimental domain with an uniformity in space filling, (2) its ability to explore the whole of the domain, and (3) its potential for sequentially where the experiments can be reused when the boundaries have not been well chosen at first (BENSALAH et al., 2010). Doehlert designs are easily applied to optimized variables and offer advantages over the Central Composite (CCD) and Box-Behnken designs, used in response surface analysis. They need fewer experiments, ResumoO presente trabalho visou verificar a influência do pH e temperatura na lise de leveduras utilizando planejamento experimental. No estudo, foi utilizado o extrato enzimático, contendo β-1,3-glucanase e quitinase líticas, obtidas do micro-organismo Moniliophthora perniciosa. O delineamento experiment...

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“…Several researchers have applied these techniques to optimize different process parameters (VANOT et al, 2002;DUTRA;MALTEZ;CARASEK, 2006;IMANDI et al, 2007).…”

Section: Doehlert Experimental Design -Yeast Cells Lysismentioning

confidence: 99%

Application of Doehlert experimental design in the optimization of experimental variables for the Pseudozyma sp. (CCMB 306) and Pseudozyma sp. (CCMB 300) cell lysis

et al. 2012

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“…Therefore, very sensitive analytical techniques such as electrothermal atomic absorption spectrometry (ETAAS) [7,8] or inductively coupled plasma-mass spectrometry (ICP-MS) [9,10] are required for its determination. However, inductively coupled plasma-atomic emission spectrometry (ICP-AES) [11] and flame atomic absorption spectrometry (FAAS) [12] do not have sufficient sensitivity for direct trace determinations of zinc. Thus, for lowering the detection limits of zinc analysis by these techniques a separation/preconcentration step is required.…”

Section: Introductionmentioning

confidence: 99%

Solid phase extraction of zinc with octadecyl silica membrane disks modified by N,N’-disalicylidene-1,2-phenylendiamine and determination by flame atomic absorption spectrometry

et al. 2008

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A procedure for separation and preconcentration of trace amounts of Zn(II) from aqueous media is proposed. The procedure is based on the adsorption of Zn2+ on octadecyl bonded silica membrane disk modified with N,N’-disalicylidene-1,2-phenylendiamine at pH 7. The retained zinc ions were then stripped from the disk with a minimal amount of 1.5 mol L-1 hydrochloric acid solution as eluent, and determined by flame atomic absorption spectrometry. Maximum capacity of the membrane disk modified with 5 mg of the ligand was found to be 226 μg Zn2+. The relative standard deviation of zinc for ten replicate extraction of 10 μg zinc from 1000 mL samples was 1.2%. The limit of detection of the proposed method was 14 ng of Zn2+ per 1000 mL. The method was successfully applied to the determination of zinc in natural water samples and accuracy was examined by recovery experiments and independent analysis by graphite furnace atomic absorption spectrometry (GFAAS).

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“…A espécie analítica presente na amostra, ao passar pela mini-coluna, é extraída pelos sítios ativos do material extrator e a quantidade de analito retido na coluna é proporcional à vazão da amostra e ao tempo de pré-concentração. O analito é extraído da mini-coluna com o auxílio de um eluente apropriado, onde a solução resultante contendo o analito é deslocada até um detector e o sinal analítico é monitorado [8].…”

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“…Entre estas técnicas, o planejamento fatorial completo é bastante empregado para avaliar a significância de variáveis [8]. O número de experimentos requeridos para isto é calculado como N = 2 k , onde k é o número de variáveis.…”

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“…O número de experimentos requeridos para isto é calculado como N = 2 k , onde k é o número de variáveis. Quando há apenas variáveis quantitativas podem-se usar pontos centrais, neste caso três replicatas, resultando em N = 2 k +3, garantindo melhor ajuste do erro estatísti-co. A matriz Doehlert é um planejamento uniforme proposto por Doehlert em 1970 e tem sido muito usado para otimização de duas variáveis, consistindo de um ponto central e seis pontos formando um hexágono, situado em um círculo [8].…”

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Otimização multivariada e aplicação do sorvente SiO2-Nb2O5 para determinação em linha de Ni(II) em matriz aquosa

et al. 2008

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IntroduçãoO níquel é um elemento natural muito abundante no meio ambiente e pode ser combinado com outros metais, tais como ferro, cobre, cromo e zinco, para formar ligas [1]. A importância da determinação de íons de elementos de transição, tais como Ni(II), em amostras ambientais, é bastante enfatizada devido a sérios riscos que esses elementos causam ao sistema biológico. As principais fontes de Ni(II) em sistemas aquáticos são provenientes da dissolução das rochas e solos, ciclos biológicos, e especialmente de processos industriais [2]. Sabe-se que a inalação de compostos que Esses metais encontram-se, em geral, em concentrações-traço e por isso é necessário o desenvolvimento de métodos analíticos que possibilitem suas determinações quantitativas de acordo com os crescentes níveis de exigência das organizações governamentais.A espectrometria de absorção atômica em chama (F AAS) é uma das técnicas mais uti-

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Development of an on-line preconcentration system for zinc determination in biological samples

Cited by 52 publications

References 22 publications

Application of Doehlert experimental design in the optimization of experimental variables for the Pseudozyma sp. (CCMB 306) and Pseudozyma sp. (CCMB 300) cell lysis

Application of Doehlert experimental design in the optimization of experimental variables for the Pseudozyma sp. (CCMB 306) and Pseudozyma sp. (CCMB 300) cell lysis

Solid phase extraction of zinc with octadecyl silica membrane disks modified by N,N’-disalicylidene-1,2-phenylendiamine and determination by flame atomic absorption spectrometry

Otimização multivariada e aplicação do sorvente SiO2-Nb2O5 para determinação em linha de Ni(II) em matriz aquosa

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