The Experts below are selected from a list of 4965 Experts worldwide ranked by ideXlab platform

Sergio Luis Costa Ferreira - One of the best experts on this subject based on the ideXlab platform.

  • Cloud Point Extraction as a procedure of separation and pre concentration for metal determination using spectroanalytical techniques a review
    Applied Spectroscopy Reviews, 2005
    Co-Authors: Marcos Almeida Bezerra, Marco Aurelio Zezzi Arruda, Sergio Luis Costa Ferreira
    Abstract:

    Abstract Cloud Point Extraction is a separation and preconcentration procedure that has been extensively applied for trace metal determination in several different matrices. Its major advantages are simple experimental procedures, low cost, high preconcentration factors, and environmental safety. These aspects include it in a set of analytical methods in agreement with the “green chemistry” principles. The surfactants characteristics and the process of micelle formation are outlined for a better understanding of the technique. After general considerations about the Cloud Point Extraction basis and its Extraction mechanism for metal chelates are considered, selected spectroanalytical techniques and their application for analysis of the micellar phase are discussed. The micellar Extraction in metal speciation analysis, the on‐line incorporation of Cloud Point Extraction to flow injection analysis, and coupling with capillary electrophoresis are described.

  • Cloud Point Extraction as a Procedure of Separation and Pre‐Concentration for Metal Determination Using Spectroanalytical Techniques: A Review
    Applied Spectroscopy Reviews, 2005
    Co-Authors: Marcos Almeida Bezerra, Marco Aurelio Zezzi Arruda, Sergio Luis Costa Ferreira
    Abstract:

    Abstract Cloud Point Extraction is a separation and preconcentration procedure that has been extensively applied for trace metal determination in several different matrices. Its major advantages are simple experimental procedures, low cost, high preconcentration factors, and environmental safety. These aspects include it in a set of analytical methods in agreement with the “green chemistry” principles. The surfactants characteristics and the process of micelle formation are outlined for a better understanding of the technique. After general considerations about the Cloud Point Extraction basis and its Extraction mechanism for metal chelates are considered, selected spectroanalytical techniques and their application for analysis of the micellar phase are discussed. The micellar Extraction in metal speciation analysis, the on‐line incorporation of Cloud Point Extraction to flow injection analysis, and coupling with capillary electrophoresis are described.

Nahid Pourreza - One of the best experts on this subject based on the ideXlab platform.

  • Indirect Cloud Point Extraction and spectrophotometric determination of nitrite in water and meat products
    Microchemical Journal, 2012
    Co-Authors: Nahid Pourreza, Mohammad Reza Fat'hi, Ali Hatami
    Abstract:

    Abstract A new indirect micelle mediated Cloud Point Extraction method has been developed for sensitive determination of trace amounts of nitrite by spectrophotometry. The method is based on the well known oxidation–reduction reaction of nitrite by iodide ion in acidic medium and Cloud Point Extraction of I 3 − formed from aqueous solution using Triton X-100. The extracted surfactant rich phase is diluted with water and its absorbance is measured at 365 nm. The effects of different operating parameters such as concentration of surfactant, KI concentration, temperature, incubation time and acid concentration on the Cloud Point Extraction were studied in details and a set of optimum conditions was obtained. A linear calibration graph was obtained in the range of 8–120 ng mL − 1 . The limit of detection (LOD) based on three times the standard deviation of the blank (3S b ) was 6.0 ng mL − 1 (n = 10) and the relative standard deviation (RSD) for determination of 60 ng mL − 1 of nitrite was 3.40% (n = 10). The method was applied to the determination of nitrite in meat products and water samples.

  • determination of allura red in food samples after Cloud Point Extraction using mixed micelles
    Food Chemistry, 2011
    Co-Authors: Nahid Pourreza, Saadat Rastegarzadeh, Arash Larki
    Abstract:

    Abstract A Cloud Point Extraction process using mixed micelles of CTAB, Triton X-114 and Triton X-100 for preconcentration and spectrophotometric determination of trace amounts of Allura red in food samples was developed. The effect of different parameters such as concentration of surfactants, electrolyte concentration, temperature and pH on the Cloud Point Extraction of Allura red was studied in detail and a set of optimum conditions were established. A linear calibration curve in the range of 20–1400 μg/L of Allura red was obtained. Detection limit based on 3S b was 7.8 μg/L and the relative standard deviation for 75 μg/L of Allura red was 3.87 ( n  = 10). The method was applied to the determination of Allura red in food samples such as candy, soft drink and jellies.

  • simultaneous Cloud Point Extraction and spectrophotometric determination of carmoisine and brilliant blue fcf in food samples
    Talanta, 2011
    Co-Authors: Nahid Pourreza, Matineh Ghomi
    Abstract:

    Abstract A novel simultaneous Cloud Point Extraction method for the determination of carmoisine and brilliant blue FCF by spectrophotometry has been developed. The method is based on the Cloud Point Extraction of carmoisine and brilliant blue FCF from aqueous solution using Triton X-100, diluting the extracted surfactant rich phase with water and measuring the absorbance at 522 and 640 nm for carmoisine and brilliant blue FCF, respectively. The effects of different parameters such as pH, concentration of surfactant and temperature on the Cloud Point Extraction of both dyes were investigated and optimum conditions were established. Linear calibration curves were obtained in the range of 0.02–3.50 μg mL −1 for carmoisine and 0.05–3.50 μg mL −1 for brilliant blue FCF under optimum conditions. Detection limit based on three times the standard deviation of the blank (3S b ) was 0.017 and 0.016 μg mL −1 ( n  = 10) for carmoisine and brilliant blue FCF, respectively. The relative standard deviation (RSD) for 0.1 μg mL −1 was 4.14 and 3.30% ( n  = 10), for carmoisine and brilliant blue FCF, respectively. The method was applied to the simultaneous determination of the dyes in different food samples.

  • micelle mediated Cloud Point Extraction and spectrophotometric determination of rhodamine b using triton x 100
    Talanta, 2008
    Co-Authors: Nahid Pourreza, Saadat Rastegarzadeh, Arash Larki
    Abstract:

    Abstract A new micelle-mediated Cloud Point Extraction method is described for sensitive and selective determination of trace amounts of rhodamine B by spectrophotometry. The method is based on the Cloud Point Extraction of rhodamine B from aqueous solution using Triton X-100 in acidic media. The extracted surfactant rich phase is diluted with water and its absorbance is measured at 563 nm by a spectophotometer. The effects of different operating parameters such as concentration of surfactant and salt, temperature and pH on the Cloud Point Extraction of rhodamine B were studied in details and a set of optimum conditions were obtained. Under optimum conditions a linear calibration graph in the range of 5–550 ng mL−1 of rhodamine B in the initial solution with r = 0.9991 (n = 15) was obtained. Detection limit based on three times the standard deviation of the blank (3Sb) was 1.3 ng mL−1 (n = 10) and the relative standard deviation (R.S.D.) for 50 and 350 ng mL−1 of rhodamine B was 2.40 and 0.87% (n = 10), respectively. The method was applied for the determination of rhodamine B in soft pastel, hand washing liquid soap, matches tip and textile dyes mixture samples.

Marcos Almeida Bezerra - One of the best experts on this subject based on the ideXlab platform.

  • Cloud Point Extraction as a procedure of separation and pre concentration for metal determination using spectroanalytical techniques a review
    Applied Spectroscopy Reviews, 2005
    Co-Authors: Marcos Almeida Bezerra, Marco Aurelio Zezzi Arruda, Sergio Luis Costa Ferreira
    Abstract:

    Abstract Cloud Point Extraction is a separation and preconcentration procedure that has been extensively applied for trace metal determination in several different matrices. Its major advantages are simple experimental procedures, low cost, high preconcentration factors, and environmental safety. These aspects include it in a set of analytical methods in agreement with the “green chemistry” principles. The surfactants characteristics and the process of micelle formation are outlined for a better understanding of the technique. After general considerations about the Cloud Point Extraction basis and its Extraction mechanism for metal chelates are considered, selected spectroanalytical techniques and their application for analysis of the micellar phase are discussed. The micellar Extraction in metal speciation analysis, the on‐line incorporation of Cloud Point Extraction to flow injection analysis, and coupling with capillary electrophoresis are described.

  • Cloud Point Extraction as a Procedure of Separation and Pre‐Concentration for Metal Determination Using Spectroanalytical Techniques: A Review
    Applied Spectroscopy Reviews, 2005
    Co-Authors: Marcos Almeida Bezerra, Marco Aurelio Zezzi Arruda, Sergio Luis Costa Ferreira
    Abstract:

    Abstract Cloud Point Extraction is a separation and preconcentration procedure that has been extensively applied for trace metal determination in several different matrices. Its major advantages are simple experimental procedures, low cost, high preconcentration factors, and environmental safety. These aspects include it in a set of analytical methods in agreement with the “green chemistry” principles. The surfactants characteristics and the process of micelle formation are outlined for a better understanding of the technique. After general considerations about the Cloud Point Extraction basis and its Extraction mechanism for metal chelates are considered, selected spectroanalytical techniques and their application for analysis of the micellar phase are discussed. The micellar Extraction in metal speciation analysis, the on‐line incorporation of Cloud Point Extraction to flow injection analysis, and coupling with capillary electrophoresis are described.

Fuensanta Sánchez Rojas - One of the best experts on this subject based on the ideXlab platform.

  • Separation and preconcentration by Cloud Point Extraction procedures for determination of ions: recent trends and applications
    Microchimica Acta, 2012
    Co-Authors: Catalina Bosch Ojeda, Fuensanta Sánchez Rojas
    Abstract:

    The Cloud Point Extraction procedure is an alternative to liquid–liquid Extraction and based on the phase separation that occurs in aqueous solutions of non-ionic surfactants when heated above the so-called Cloud Point temperature. We review the more recent applications for determination of ions by means of this procedure for sample preparation over the range 2009 to first part of 2011. Following an introduction, the article covers aspects of Cloud Point Extraction of one metal ion, two metals ions simultaneously, three metal ions simultaneously, multielement analysis, anions analysis, and on-line Cloud Point Extraction. One hundred sixteen references are cited. Figure Scheme of the CPE procedure. CPE techniques exploit a property of most non-ionic surfactants that form micelles in aqueous solution: they become turbid when heated to the appropriate Cloud Point temperature. Above the Cloud Point temperature, the micellar solution separates into a small, surfactant rich phase and a larger diluted aqueous phase

  • separation and preconcentration by Cloud Point Extraction procedures for determination of ions recent trends and applications
    Mikrochimica Acta, 2012
    Co-Authors: Catalina Bosch Ojeda, Fuensanta Sánchez Rojas
    Abstract:

    The Cloud Point Extraction procedure is an alternative to liquid–liquid Extraction and based on the phase separation that occurs in aqueous solutions of non-ionic surfactants when heated above the so-called Cloud Point temperature. We review the more recent applications for determination of ions by means of this procedure for sample preparation over the range 2009 to first part of 2011. Following an introduction, the article covers aspects of Cloud Point Extraction of one metal ion, two metals ions simultaneously, three metal ions simultaneously, multielement analysis, anions analysis, and on-line Cloud Point Extraction. One hundred sixteen references are cited.

Qiao Feng Wang - One of the best experts on this subject based on the ideXlab platform.

  • determination of isoquercitrin in rat plasma by high performance liquid chromatography coupled with a novel synergistic Cloud Point Extraction
    Journal of Chromatography B, 2018
    Co-Authors: Jun Zhou, Qiao Feng Wang
    Abstract:

    Abstract A novel improved preconcentration method known as synergistic Cloud Point Extraction was established for isoquercitrin preconcentration and determination in rat plasma prior to its determination by high performance liquid chromatography. Synergistic Cloud Point Extraction greatly simplified isoquercitrin Extraction and detection. This method was accomplished at room temperature (about 22 °C) in 1 min with the nonionic surfactant Tergitol TMN-6 as the extractant, n-octanol as Cloud Point revulsant and synergic reagent. Parameters that affect the synergistic Cloud Point Extraction processes, such as the concentrations of Tergitol TMN-6, volume of n-octanol, sample pH, salt content and Extraction time were investigated and optimized. Under the optimum conditions, the calibration curve for the analyte was linear in the range from 5 to 500 ng mL−1 with the correlation coefficients greater than 0.9996. Meanwhile, limit of detection (S/N = 3) was less than 1.6 ng mL−1 and limit of quantification (S/N = 10) was less than 5 ng mL−1. It demonstrated that the method can be successfully applied to the pharmacokinetic investigation of isoquercitrin.