Application of Nb 2 O 5 -SiO 2 in Pre-Concentration and Determination of Copper and Cadmium by Flow System with Flame Atomic Absorption Spectrometry

Budziak, Dilma; Silva, Edson Luiz da; Campos, Sílvia Denofre de; Carasek, Eduardo

doi:10.1007/s00604-002-0934-4

Cited by 23 publications

(11 citation statements)

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“…They included atomic absorption spectrometry [4,5], fast neutron activation analysis [6], inductively coupled plasma atomic emission spectrometry [7], and electrochemical methods [8][9][10]. Among these methods, some of them needed relatively high cost apparatus and were not easily adaptable for online monitoring.…”

Section: Introductionmentioning

confidence: 99%

Highly sensitive fluorescent sensor for copper (II) based on amplified fluorescence quenching of a water-soluble NIR emitting conjugated polymer

et al. 2012

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We have synthesized the near-infrared watersoluble conjugated polymer poly[2,5-di(propyloxysulfonate)-1,4-phenylene-ethynylene-9,10-anthrylene (referred to as PPEASO3). Its fluorescence (at wavelengths between 650 and 800 nm following photoexcitation at 550 nm) is efficiently quenched by Cu(II) ions, while other physiologically relevant metal ions do not cause significant quenching at the same concentrations. Under optimum conditions, fluorescence intensity is inversely proportional to the concentration of Cu (II). The calibration curve displays two linear regions over the range of 0-3.2×10 −7 mol L −1 and 3.2×10 −7 mol L −1 to 1.0× 10 −4 mol L −1 of Cu(II), respectively. The long-wavelength excitation and emission can substantially reduce interferences by the autofluorescence and light scattering of biological matter under UV excitation. The method was successfully applied to the determination of Cu(II) in synthetic and tea samples.

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Section: Introductionmentioning

confidence: 99%

Highly sensitive fluorescent sensor for copper (II) based on amplified fluorescence quenching of a water-soluble NIR emitting conjugated polymer

et al. 2012

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“…27 It is also important to emphasize that the metal oxide dispersed on the silica matrix presents chemical and physical properties different from those observed for bulk metal oxide, including a higher capacity for ion exchange. 28 The use of SiO 2 Particular interest was given to zinc ions owing to their intrinsic importance in various biological systems, where it is found in more than 80 enzymes (as in carboxypeptidase, carbonic anhydrase, bovine superoxide dismutase, etc.) 36 and environmental samples, as well as to their trace amount commonly found in these samples.…”

Section: Introductionmentioning

confidence: 99%

Silica-alumina-niobia (SiO2/Al2O3/Nb2O5) matrix obtained by the sol-gel processing method: new material for online extraction of zinc ions

Tarley

Ávila

Segatelli

et al. 2010

J. Braz. Chem. Soc.

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No presente trabalho foi avaliado um novo material como adsorvente, SiO 2 /Al 2 O 3 /Nb 2 O 5 (designado SiAlNb), empregado na determinação e pré-concentração online de Zn 2+ por um método espectrofotométrico por injeção em fluxo. O método de pré-concentração é baseado na adsorção de Zn 2+ em meio alcalino (pH 9,0) sobre a superfície de SiAlNb. A etapa de eluição é realizada usando solução de HNO 3 e é seguida da reação dos íons Zn , respectivamente. De acordo com o modelo linear de Langmuir, a capacidade máxima de adsorção foi de 7,0 mg de Zn 2+ por grama de SiAlNb. O método proposto foi aplicado com sucesso na determinação de Zn 2+ em amostras de água (lago, mineral e torneira) e material certificado de referência (TORT-2 Lobster Hepatopancreas).In the present work, a new material, SiO 2 /Al 2 O 3 /Nb 2 O 5 (designated as SiAlNb), was evaluated as an adsorbent in a flow injection spectrophotometric method for online preconcentration and determination of trace amounts of Zn 2+ ions. The preconcentration method is based on Zn 2+ adsorption onto the surface of SiAlNb in alkaline medium (pH 9.0). The elution step is carried out using HNO 3 solution, followed by reaction of the Zn 2+ ions with 1-(2-piridylazo)-2-naphtol (pan) in ammoniacal buffer solution (pH 9.3) containing of SiAlNb. The proposed method was successfully applied to the Zn 2+ determination in water samples (lake, mineral, tap) and certified reference material (TORT-2 Lobster Hepatopancreas).

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“…As amostras coletadas foram previamente submetidas ao procedimento de micro extração e foi determinado que o teor original de chumbo e cádmio estava abaixo do limite de detecção do método proposto. Além do estudo da recuperação analí-tica realizado com amostras de água enriquecidas com chumbo e cádmio, os resultados obtidos com o método proposto foram comparados com aqueles obtidos por uma metodologia alternativa de preparo de amostra (extração em fase sólida) 22 . Os resultados destes estudos estão apresentados na Tabela 2 e são indicativos de que os íons chumbo e cádmio podem ser quantitativamente recuperados das amostras testadas.…”

Section: Características Analíticas Do Métodounclassified

Pré-concentração de chumbo e cádmio em um sistema de micro extração líquido-líquido e determinação por espectrometria de absorção atômica com chama

Carasek¹,

Tonjes²,

Scharf³

2002

Quím. Nova

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lead and cadmium in aqueous samples using solvent microextraction and dithizone as complexing agent with FAAS was developed. Solvent microextraction parameters were optimized. The effect of foreign ions on the extraction yields was studied. The extraction was carried out until the aqueous to organic phase ratio achieved a 250 fold preconcentration of metals. For preconcentration times of 4 min the 3s detection limits, relative standard deviations (n=7) and linear calibration ranges were 1.6 mg L -1 , 5.8% and 10.0 -80.0 mg L -1 for lead and 11.1 ng L -1 , 5.9% and 0.3 -3.0 mg L -1 for cadmium, respectively. The solvent microextraction procedure presented here was applied to the determination of lead and cadmium in natural waters.Keywords: preconcentration; dithizone; flame atomic absorption spectrometry; natural waters. INTRODUÇÃOEmbora o desenvolvimento da instrumentação tenha possibilitado avanços em muitos aspectos da Química Analítica, em muitos casos a instrumentação disponível não apresenta sensibilidade analí-tica suficiente para a determinação de traços. Além disso, é comum não se analisar quimicamente amostras em sua forma original (aquosa ou sólida), pois elas podem conter espécies interferentes e serem incompatíveis com os equipamentos analíticos. Para contornar tais problemas são empregados procedimentos de preparo da amostra, os quais incluem várias etapas: coleta, armazenagem, solubilização, extração, pré-concentração, isolamento dos compostos de interesse e análise qualitativa e quantitativa. As etapas de extração e pré-concentração dos analitos são ainda o "calcanhar de Aquiles" de todo o procedimento analítico devido ao fato dessas etapas serem lentas, apresentarem a possibilidade de contaminação e a perda das espé-cies de interesse durante o manuseio da amostra. Assim, o desenvolvimento de procedimentos para a separação e pré-concentração de contaminantes de matrizes ambientais têm sido propostos, como por exemplo, extração líquido-líquido 1-4 , co-precipitação 5

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Application of Nb 2 O 5 -SiO 2 in Pre-Concentration and Determination of Copper and Cadmium by Flow System with Flame Atomic Absorption Spectrometry

Cited by 23 publications

References 0 publications

Highly sensitive fluorescent sensor for copper (II) based on amplified fluorescence quenching of a water-soluble NIR emitting conjugated polymer

Highly sensitive fluorescent sensor for copper (II) based on amplified fluorescence quenching of a water-soluble NIR emitting conjugated polymer

Silica-alumina-niobia (SiO2/Al2O3/Nb2O5) matrix obtained by the sol-gel processing method: new material for online extraction of zinc ions

Pré-concentração de chumbo e cádmio em um sistema de micro extração líquido-líquido e determinação por espectrometria de absorção atômica com chama

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