Flame atomic absorption determination of manganese(II) in natural water after cloud point extraction

O presente trabalho descreve um procedimento para emulsificação-microextração de quantidades traço de íons cobalto e manganês sem uso de ligantes, assistido por ultrasom, em amostras de água. Os metais extraídos foram determinados por espectrometria de absorção atômica em chama (FAAS). Foram estudados e otimizados diversos fatores que influenciam a eficiência de extração de íons cobalto e manganês, tais como tipo e volume do solvente de extração, pH, tempo de extração, temperatura de extração e força iônica. Íons cobalto e manganês foram extraídos em um meio emulsificado acusticamente com 20,0 mL de tetracloreto de carbono. Os limites de detecção foram 0,8 e 0,5 ng mL -1 para Co(II) e Mn(II), respectivamente (3 S b /m). Oito determinações em replicata de uma mistura de 100,0 ng mL -1 de cobalto e 50,0 ng mL -1 de manganês resultaram em absorbâncias média de 0,055 e 0,061 com desvios padrão relativos de 3,2% e 2,9%, respectivamente. O procedimento proposto foi aplicado com sucesso na determinação de cobalto e manganês em amostras de água.The present work reports a procedure based on ligandless-ultrasound-assisted emulsificationmicroextraction of trace amounts of cobalt and manganese ions in water samples prior to flame atomic absorption spectrometry determination (FAAS). Different factors influencing the extraction efficiency of cobalt and manganese ions, such as type and volume of the extraction solvent, pH, extraction time, extraction temperature, and ionic strength were studied and optimized. Cobalt and manganese ions were extracted in an acoustically emulsified media by 20.0 µL carbon tetrachloride. The limits of detection were 0.8 and 0.5 ng mL -1 for Co(II) and Mn(II), respectively (3S b /m). Eight replicate determinations of a mixture of 100.0 ng mL -1 cobalt and 50.0 ng mL -1 manganese gave a mean absorbance of 0.055 and 0.061 with relative standard deviations of 3.2 and 2.9%, respectively. The proposed procedure was successfully applied to determination of cobalt and manganese in water samples.

Section: Comparisonmentioning

confidence: 99%

Ultrasound-assisted emulsification microextraction of trace amounts of Co and Mn ions prior to flame atomic absorption spectrometry

Mohammadi¹,

Afzali²,

Baghelani³

et al. 2011

“…14 The cloud point extraction of water-soluble metal complexes with 4-(2-pyridylazo) resorcinol (PAR) has been described before. 15,16 A surfactant media is necessary to dissolve chelating reagents such as 1-(2-thiazolylazo)-2-naphtol (TAN), 17 dithizone 18 and 1-(2-pyridylazo)2-naphtol (PAN). 1 Cloud point extraction has been extensively described as a separation and pre-concentration procedure for metals prior to their determination by atomic spectrometric techniques.…”

Section: Introductionmentioning

confidence: 99%

“…Methanol or ethanol plus nitric acid have been described to facilitate the introduction of micellar phases into F AAS, 10 ET AAS, 11 ETV-ICP-MS 12 and ICP-MS. 13 Tetrahydrofuran has been used for introduction into ETAAS, 18 or just water has been applied for dilution. 15,20 The combination of electrothermal devices using appropriately programmed vaporization temperatures avoided matrix interferences in the atomic spectrometry detection of micellar phases. 11,12,18 The flow injection of small sample volumes (100 µL) by using an ultrasonic nebulizer with a dessolvation unit avoided the main drawbacks of introducing micelles dissolved in methanol into an ICP-MS.…”

Section: Introductionmentioning

confidence: 99%

Sequential cloud point extraction of trace elements from biological samples and determination by inductively coupled plasma mass spectrometry

Giné¹,

Patreze²,

Silva³

et al. 2008

A extração no ponto nuvem (CPE) foi realizada em duas etapas seqüenciais para a determinação de elementos traço em soro humano, sangue animal e dieta alimentar por espectrometria de massas com fonte de plasma indutivamente acoplado. A primeira CPE foi realizada adicionando dietil-ditiofosfato, Triton ® X-114 seguida de aquecimento a 40 °C, centrifugação e esfriamento a 0 °C. A fase rica em surfactante foi separada para determinar Cd, Pb e Cu pela técnica de quantificação por diluição isotópica. As medidas das razões isotópicas foram caracterizadas por RSD < 0.7%. O pH da solução empobrecida em surfactantante foi ajustado entre 4 e 5 antes da adição de 4-(2-pirilidazo)resorcinol, Triton ® X-114 e seguiram-se os procedimentos para atingir o ponto nuvem. Na segunda fase rica em surfactante extraída foram quantificados Co e Ni pelo método de adições de padrão com RSD < 2%. Recuperações entre 85 a 96% foram obtidas para todos os elementos. A exatidão foi aferida pela análise de materiais de referência com valores recomendados e certificados.A two-step sequential cloud point extraction (CPE) of trace elements from small sample volumes of human serum, animal blood, and food diet is proposed to gain analytical information in the analysis by inductively coupled plasma mass spectrometry. The first CPE was attained by adding O,O-diethyldithiophosphate, the non ionic surfactant Triton ® X-114 followed by heating at 40 °C, centrifugation and cooling at 0 °C. The resulting surfactant-rich phase was separated to determine Cd, Pb and Cu by isotope dilution. Isotope ratio measurements presented RSD < 0.7%. The residual surfactant-poor phase solution had the pH adjusted in the range 4 to 5 before the chelating reagent, 4-(2-pyridylazo) resorcinol plus surfactant Triton ® X-114 were added followed by the sequence to attain the CPE. Co and Ni were quantified in the second extracted surfactantrich phases by standard additions method with RSD < 2%. Recoveries from 85 to 96% were obtained for all elements. Analyzing reference materials with certified and recommended values assessed accuracy.Keywords: sequential cloud point extraction, CPE, inductively coupled plasma mass spectrometry, isotope dilution, biological samples, trace elements IntroductionSurfactant mediated phase separation constitutes the basis for the approach known as cloud point extraction 1 which is a liquid-liquid extraction alternative to that of organic solvents. The main parameter to attain a surfactant monomer agglomeration in a micelle-rich phase is the surfactant concentration at the cloud point temperature. The temperature-concentration phase diagram is specific for each surfactant. 2 The effect of additives such as salts and other surfactants also has to be considered. 1,3 The first application of cloud point extraction for analytical purposes described the micelle aggregation of hydrophobic anionic metal complexes. 2 The ability of surfactant micelles to bind organic compounds separated by CPE was applied for pre-concentration of organic Sequential Cloud Poin...

“…[21][22][23][24][25][26][27][28] CPE combination with FAAS for determination of manganese and iron has also been reported. [29][30][31][32][33][34] In the present work we report the results obtained from studying the CPE to determine the Cu content of sea and river waters by using Cupron as a complexing agent and Triton X-114 as a surfactant. FAAS was used for the detection.…”

Section: Introductionmentioning

confidence: 99%

Determination of trace amounts of copper in river and sea water samples by flame atomic absorption spectrometry (FAAS) after cloud-point preconcentration

Goudarzi

2007

Este trabalho propõe um novo método de pré-concentração baseado em ponto nuvem para a determinação de cobre. O reagente 1,5-difenil-benzoína (Cupron) foi usado como complexante e Triton X-114 foi adicionado como surfactante. Após a separação das fases e diluição da fase rica em surfactante com metanol em meio acidificado foi feita a determinação do cobre por espectrometria de absorção atômica com chama (FAAS). O fator de enriquecimento do cobre, após a otimização das condições de complexação e otimização, foi igual a 88. O procedimento proposto possibilitou a determinação de cobre com limite de detecção igual a 0,04 μg L -1 . O procedimento foi aplicado com sucesso na determinação de cobre em amostras de água de rio e de mar. O desvio padrão relativo foi de 1,9 % para o Cu. Também foram investigados efeitos de interferência de alguns ânions e cátions.A new preconcentration method was proposed using the cloud point approach for copper determination. The reagent 1,5-diphenyl-benzoin (Cupron) was used as a complexing agent and Triton X-114 was added as a surfactant. After phase separation, dilution of the surfactantrich phase was carried out using acidified methanol and the copper content was subsequently measured by flame atomic absorption spectrometry. After optimization of the complexation and extraction conditions, the enrichment factor for Cu was found to be 88. The proposed procedure allowed determination of the copper content with the detection limit of 0.04 μg L -1 . The method was successfully applied to copper determination in river and sea water samples. The relative standard deviation for the method was found to be 1.9 % for Cu. The interference effects of some anions and cations were also investigated.