Evaluation and Optimization of the Factors Affecting Nonionic Surfactant-Mediated Phase Separations

Frankewich, Raymond P.; Hinze, Willie L.

doi:10.1021/ac00079a005

Cited by 203 publications

(134 citation statements)

References 31 publications

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“…In order to employ the lowest possible equilibration temperature to the efficient separation of phases, the equilibration temperature was examined. Theoretically, the optimal equilibration temperature of the extraction occurs when the equilibration temperature is 15-20 • C greater than the cloud point temperature of surfactant [26]. Fig.…”

Section: Effect Of the Equilibration Temperaturementioning

confidence: 99%

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Determination of estrogens in water by HPLC–UV using cloud point extraction

Wang

Cai

et al. 2006

Talanta

135

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A method based on cloud point extraction was developed to determine four kinds of estrogens: estriol (E3), estradiol (E2), estrone (E1), and progesterone (P) in water by high performance liquid chromatography separation and ultraviolet detection (HPLC-UV). The non-ionic surfactant Triton X-114 was chosen as extractant solvent. The parameters affecting extraction efficiency, such as concentrations of Triton X-114 and Na 2 SO 4 , equilibration temperature, equilibration time and centrifugation time were evaluated and optimized. Under the optimum conditions, preconcentration factors of 99 for E3, 73 for E2, 152 for E1 and 86 for P were obtained for 10 mL water sample. The detection of limitation was 0.23 ng mL −1 for E3, 0.32 ng mL −1 for E2, 0.25 ng mL −1 for E1 and 5.0 ng mL −1 for P. The proposed method was successfully applied to the determination of trace amount of estrogens in wastewater treatment plant (WWTP) effluent water and exposure water with 10 ng mL −1 E2 for toxicological study in our lab. For the case of WWTP effluent water samples, no estrogen was found. The accuracy of the proposed method was tested by recovery measurements of spiked samples and good recoveries of 81.2-99.5% were obtained.

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Section: Effect Of the Equilibration Temperaturementioning

confidence: 99%

“…When the cloud point extraction procedure was processed at equilibration temperature of the surfactant, the best extraction effect was achieved [26]. Thus, it is necessary to examine the effect of temperature on cloud point extraction.…”

Section: Effect Of the Equilibration Temperaturementioning

confidence: 99%

Determination of estrogens in water by HPLC–UV using cloud point extraction

Wang

Cai

et al. 2006

Talanta

135

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“…This ratio increases with a decrease in the concentration of the surfactant. 29 However, since the volume of the surfactant-rich phase must be manageable, a compromise must be reached so that the surfactant concentration will allow a high phase ratio and a manageable surfactant-rich phase. The phases ratio is an important factor, which has an effect on the extraction recovery of cations.…”

Section: Sample Sizesmentioning

confidence: 99%

Simultaneous Cloud-Point Extraction of Nine Cations from Water Samples and Their Determination by Flame Atomic Absorption Spectrometry

Farajzadeh

Fallahi

2006

ANAL. SCI.

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Several analytical techniques, such as atomic absorption spectrometry (AAS), inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS), are available for the determination of trace metals with sufficient sensitivity for most applications. However, the determination of trace metal ions in natural water samples is difficult due to various factors, particularly their low concentration and matrix effects.Preconcentration and separation can solve these problems and lead to a higher confidence level and an easy determination of trace elements by less sensitive, but more accessible instrumentation, such as flame atomic absorption spectrometry (FAAS) Cloud-point extraction (CPE) is related to the conventional LLE, and is used in micellar liquid chromatography (MLC). 7The first applications of phase separation based on the cloudpoint phenomenon refer to the extraction of metal ions forming complexes that are sparingly soluble in water. The efficiency of the process depends on the hydrophobicity of the ligand and of the complex formed, on the apparent equilibrium constants in the micellar medium, and on the formation kinetics of the complex and on the transference between the phases. This type of extraction by the cloud-point method was initially described by Watanabe and coworkers 8 for the preconcentration of Zn(II) using 1-(2-pyridylazo)naphthol (PAN) as a ligand and PONPE 7.5 as an extractant. Later, this methodology was also applied to the determination of different metal ions in different types of samples. 9 Like for all other established LLE methods, the metal ion is required to be in the uncharged chelated form prior to its extraction to the organic phase.The phase separation phenomenon has also been used for the extraction and preconcentration of metal ions after the formation of sparingly water-soluble complexes. 10 U, 11 Er 12 and Gd 13 were determined by spectrophotometry by room temperature phosphorescence; Cu, 14 Cd, 15 Ni and Zn, 16 Ag and Au, 17 by FAAS after CPE using complexing agents. Gold and lead were extracted efficiently without a complexing agent, using a non-ionic surfactant, such as poly oxyethylene nonyl phenyl ether (PONPE 7.5). Gold 18 in the aqueous phase was determined by ICP-MS and in the surfactant phase by a calculation based on mass balances. Lead 19 in the surfactant-rich phase was determined by FAAS after diluting with ethanol. Recently, the determination of trace elements by X-ray fluorescence spectrometry 20 and ultrasonic nebulization ICP-MS using phase separation with a surfactant have been reported. reviewed the use of surfactant-based assemblies in analytical atomic spectrometry. Also, concentration by CPE has been established for a number of trace organic pollutants from an aqueous phase. 22Based on the present work we report on the results obtained in a study of the simultaneous cloud-point preconcentration of Cu 2+ , Mn 2+ , Ni 2+ , Cd 2+ , Fe 3+ , Co 2+ , Zn 2+ , Cr 3+ and Pb 2+ after the formation of a compl...

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“…It is reported that the greatest analyte preconcentration factor is achieved when the CPE process is conducted with equilibration temperatures that are well above the cloud point temperature of the surfactant. 31 Increasing time and temperature is necessary for having complete reaction, facile separation and complete pre-concentration, therefore, by increasing them the absorbance will be increased. From the optimum points on, there is a probability for collapsing the formed complex and weak clouding of the surfactants, therefore, absorbance will be decreased.…”

Section: Effects Of Equilibration Temperature and Timementioning

confidence: 99%

Cloud Point Extraction and Spectrophotometric Determination of Uranium (VI) in Water Samples after Mixed Micelle-Mediated Extraction Using Chromotrope 2R as Complexing Agent

Gholivand¹,

Omidi²,

Khodadadian³

2012

Croat. Chem. Acta

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Abstract. A rapid, selective and sensitive method for the preconcentration and determination of uranium (VI) by cloud point extraction (CPE) was developed. The method was based on the color reaction of 5.00 ng mL −1 uranium (VI) with 1.5×10 −4 mol L −1 of chromotrope 2R in the presence of 0.015 mol L −1 potassium iodide at pH 8 in HEPES buffer and mixed micelle-mediated extraction of complex. The mixture of a nonionic surfactant (0.2 % (v/v) of (Triton X-114) and a cationic (2.0×10−4 mol L −1 of CTAB) was utilized as a suitable micellar medium for preconcentration and extraction of uranium (VI) complexes. Effect of extraction and reaction parameters was studied and optimum parameters were established. The analytical characteristics of the method (e.g. linear range, limit of detection, preconcentration and improvement factors) were obtained. Linearity was obeyed in the range of 0.2−10 ng mL −1 of uranium (VI) with a detection limit of 0.035 ng mL −1 . The diverse ion effect of some anions and cations on the extraction efficiency of target ions was tested. The proposed method was successfully applied for the determination of uranium (VI) in various water samples. (doi: 10.5562/cca1922)

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Evaluation and Optimization of the Factors Affecting Nonionic Surfactant-Mediated Phase Separations

Cited by 203 publications

References 31 publications

Determination of estrogens in water by HPLC–UV using cloud point extraction

Determination of estrogens in water by HPLC–UV using cloud point extraction

Simultaneous Cloud-Point Extraction of Nine Cations from Water Samples and Their Determination by Flame Atomic Absorption Spectrometry

Cloud Point Extraction and Spectrophotometric Determination of Uranium (VI) in Water Samples after Mixed Micelle-Mediated Extraction Using Chromotrope 2R as Complexing Agent

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