Cloud Point Extraction as a Preconcentration Step Prior to Capillary Electrophoresis

Carabias‐Martínez, Rita; Rodríguez‐Gonzalo, Encarnación; Domínguez-Alvarez, and J.; Hernández-Méndez, J.

doi:10.1021/ac9812227

Cited by 98 publications

(48 citation statements)

References 25 publications

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“…17 It is based on a ternary component solvent system like homogeneous liquid-liquid extraction (HLLE) 18 and cloud point extraction (CPE). 19 The advantages of the DLLME method are rapidity, low cost and high enrichment factors. Its main drawbacks are the difficulty to automate and the necessity of using a third component (disperser solvent), which usually decreases the partition coefficient of analytes into the extractant solvent.…”

Section: Introductionmentioning

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

J. Braz. Chem. Soc.

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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.

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Section: Introductionmentioning

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

J. Braz. Chem. Soc.

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“…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.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…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 compounds prior to the separation of species by capillary electrophoresis 3 and chromatography. 4 The surfactants octylphenoxy polyethoxyethanol (Triton ® X-114) and polyoxyethylene(7.5)nonylphenyl ether (PONPE ® 7.5) with cloud point temperatures (CPT) below 40 °C and 20 °C, respectively, have been used preferentially for cloud point extraction of soluble metal ions complexes.…”

Section: Introductionmentioning

confidence: 99%

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

Giné¹,

Patreze²,

Silva³

et al. 2008

J. Braz. Chem. Soc.

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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...

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“…As a new and environmentally friendly liquid-liquid extraction method, cloud point extraction (CPE) has been employed in analytical chemistry to separate and preconcentrate both organic compounds [21][22][23] and metal ions [24][25][26][27][28][29][30] in recent years. Compared with other methods reported for the preconcentration of tin, especially the traditional liquid-liquid extraction method, CPE can yield high enrichment factors with relatively small volumes of samples, it is simple and safe and requires no additional special instruments or dangerous solvents.…”

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confidence: 99%

Preconcentration and Determination of Tin in Water Samples by Using Cloud Point Extraction and Graphite Furnace Atomic Absorption Spectrometry

Yuan

Jiang

et al. 2005

Microchim Acta

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Abstract. A method based on cloud point extraction and graphite furnace atomic absorption spectrometry (GFAAS) was developed for the analysis of trace tin in water samples. After cloud point extraction, the tin in the water samples was preconcentrated and successfully separated from most interferents. During the procedure, 8-hydroxyquinoline (8-HQ) was used as chelating reagent, and Triton X-114 was added as surfactant. The parameters affecting the sensitivity and the extraction efficiency, such as solution pH, concentration of 8-HQ and Triton X-114, equilibration temperature and centrifuge time, were evaluated and optimized. Under the optimum conditions, a preconcentration factor of 96.2 was obtained for a 20 mL water sample. The detection limit (LOD) was as low as 0.012 ng mL À1 , and the analytical curve was linear in the range of 0.05-2.0 ng mL À1 with satisfactory precision (RSD <4.1%). The proposed method was successfully applied to the determination of trace tin in water samples with recoveries in the range of 85.0-112.0%.

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Cloud Point Extraction as a Preconcentration Step Prior to Capillary Electrophoresis

Cited by 98 publications

References 25 publications

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

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

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

Preconcentration and Determination of Tin in Water Samples by Using Cloud Point Extraction and Graphite Furnace Atomic Absorption Spectrometry

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