Mixed-micelle Cloud Point Extraction Research Articles

Selective removal of lanthanum from monazite – (Nd) ores by pH-controlled mixed micelle cloud point extraction

A novel extraction method via cloud point extraction was used for the pH- selective separation of lanthanum ions from a number of real samples. The formation of a binary complex between La(III) with cetyltrimethyl ammonium bromide (CTAB) and Eriochrome cyanine R (ECR) is the main idea for the proposed study. The obtained complex could be extracted easily by Triton X-114 at 45 °C. The amount of La(III) was determined before and after separation process using an ICP-OES. The primary factors controlling the extraction of La3+ were extensively examined. To cause the clouding phenomenon and, achieve high extraction efficiency, KNO3 and CTAB must be present. The extraction efficiency was greater than 95% under ideal conditions for the concentrations strating from 0.09 to 60 µg mL−1 and a low detection limit (0.3 μg L- 1) with a preconcentration factor of 100. Moreover, by simply changing the pH of the aqueous phase, La(III) can be extracted with high selectivity from a variety of complicated matrices. The findings showed that at pH 3.5, La3+ completely extracted in the micellar phase but Nd(III) does not separate at all. These results demonstrate the reliability of the new method for selective separation of La(III).

PH-controlled mixed micelle cloud point extraction for selective removal of trace levels of iron from titanium concentrates

Removal of trace iron contaminations from valuable concentrates such as titanium is necessary to obtain highly-pure metals. In this regard, a new green mixed-micelle cloud point extraction is proposed to preferentially remove trace concentrations of iron from various geological samples. The developed procedure is based on the formation of a ternary complex of Fe(III) with eriochrome cyanine R (ECR) and cetyltrimethylammonium bromide (CTAB) that is simply extracted by Triton X-114 in the existence of KNO3 at 35 °C. The concentration of Fe(III) in the surfactant-rich phase was detected by ICP-OES. The main parameters influencing the extraction efficiency of Fe(III) were investigated systematically. The presence of KNO3 and CTAB is crucial to induce the clouding phenomena, consequently, achieving high extraction efficiency. At the optimum conditions, the extraction efficiency of Fe(III) was higher than 98.50% in the concentration range of 0.03–80 mg L−1, accompanied by an enrichment factor of 100. Interestingly, Fe(III) can be selectively extracted from complex matrices by a simple modulation of the aqueous phase pH. Fe(III) is completely extracted in the micellar phase at pH 1.0, where no separation of Ti(IV) is observable. These findings reflect the validity of the developed method for preferential removal of trace concentrations of iron from different metal concentrates.

A new sequential and simultaneous speciation analysis of thallium in coal effluents by graphite furnace atomic absorption spectrometry after a novel ligandless mixed micelle cloud point extraction

ABSTRACT A novel sequential/simultaneous extraction procedure was developed for determining Tl(I) and Tl(III) and total Tl in coal mine effluents. In this method, the selective formation of anionic species of Tl(I) and Tl(III) with HCl and diethylenetriamine pentaaceticacid (DTPA), respectively, were introduced in a mixed micelle cloud point extraction. An Aliquat-336 and Triton X-114 aggregates acted as ion-pair and extracting agents. In sequential extraction, the hydrophilic Tl(III)-DTPA2−, first reacted with cationic aggregate through electrostatic interaction and extracted into a small aggregate rich phase and leaves the cationic Tl(I) in supernatant. This was subjected to a similar extraction after converting Tl(I) into TlCl3 2− on addition of HCl. In simultaneous extraction, total Tl was extracted by adapting a similar extraction, adding HCl and DTPA, avoiding the chelating and oxidation/reducing agents. Parameters affecting the process are optimised using GFAAS. Under the optimised conditions, the detection limit and pre-concentration factor were 15 pg mL−1 and 25, respectively for both sequential and simultaneous extractions. The recoveries of Tl(III) and Tl(I) were between 85% and 104% in the range of 0.5 to 3 ng mL−1. A certified reference material, NIST 1643c, was used to verify the accuracy of the procedure. The method was applied to natural waters and coal effluents.

A Novel Synergetic Salt- and Acid-induced Ligandless Mixed Micelle Cloud Point Extraction of Ultratrace Levels of Cd, Hg, Bi, and Tl From Petrochemical Effluents Followed by ETAAS Determination

A Novel Synergetic Salt- and Acid-induced Ligandless Mixed Micelle Cloud Point Extraction of Ultratrace Levels of Cd, Hg, Bi, and Tl From Petrochemical Effluents Followed by ETAAS Determination

Green technology for monitoring the quality of water: determination of toxic trace analyte concentrations using multielemental mixed micelle cloud point extraction

AbstractA simple multielemental mixed micelle cloud point extraction procedure has been developed for the simultaneous separation and preconcentration of toxic trace analytes from natural and wastewater samples prior to their determination by electrothermal atomic absorption spectrometry. The analytes Cr, Be, Pb, Cd, Tl, and Hg were converted simultaneously, as hydrophilic anionic iodide species formed with KI in the presence of HCl. The method is based on the formation of extractable ion associates of anionic iodide species with solubilizing cationic and hydrophobic sites of mixed micelles. The mixed micelles are formed by cationic, Aliquat-336 (N-methyl-N,N,N-trioctylammonium chloride) and nonionic, Triton X-114. The ion associates formed are preconcentrated from bulk aqueous phase into a small mixed micelle-rich phase, avoiding the addition of an external chelating agent. The parameters affecting the process are evaluated and optimized. The recoveries of anaytes are in the range of 86–102% at 0.1–10 μg...

Preconcentration/separation of lead at trace level from water samples by mixed micelle cloud point extraction

A mixed micelle-mediated cloud point extraction procedure was developed for lead. Triton-X114 and benzyldimethyl hexadecyl-ammonium chloride were used as mixed micellar medium. Lead(II) was reacted with 4-(2-pyridylazo) resorcinol at pH 6.0 to form hydrophobic chelates. The parameters including pH, ligand volume, concentrations of surfactants and centrifugation time were optimized. The effect of some common ions was also tested. The limit of detection was 1.15μgL−1 with preconcentration factor of 50. The accuracy of method was evaluated by the analysis of certified reference materials. The method was successfully applied to determination of levels of lead in water samples.

Mixed micelle cloud point-magnetic dispersive μ-solid phase extraction of doxazosin and alfuzosin

Mixed micelle cloud point extraction (MM-CPE) combined with magnetic dispersive μ-solid phase extraction (MD-μ-SPE) has been developed as a new approach for the extraction of doxazosin (DOX) and alfuzosin (ALF) prior to fluorescence analysis. The mixed micelle anionic surfactant sodium dodecyl sulfate and non-ionic polyoxyethylene(7.5)nonylphenylether was used as the extraction solvent in MM-CPE, and diatomite bonding Fe3O4 magnetic nanoparticles were used as the adsorbent in MD-μ-SPE. The method was based on MM-CPE of DOX and ALF in the surfactant-rich phase. Magnetic materials were used to retrieve the surfactant-rich phase, which easily separated from the aqueous phase under magnetic field. At optimum conditions, a linear relationship between DOX and ALF was obtained in the range of 5–300ngmL−1, and the limits of detection were 0.21 and 0.16ngmL−1, respectively. The proposed method was successfully applied for the determination of the drugs in pharmaceutical preparations, urine samples, and plasma samples.

Determination of Cd, Pb, Cu, Ni and Mn in effluents and natural waters by a novel salt induced mixed-micelle cloud point extraction using ETAAS

A novel salt induced low temperature mixed-micelle cloud point extraction procedure is developed for simultaneous separation and pre-concentration of Cd, Pb, Cu, Mn and Ni from industrial effluents and natural water matrices. Electrothermal atomic absorption spectrometry has been used for their determination. The mixed-micelles are formed by micelle–micelle interaction of Triton X-114 and sodium dodecyl sulfate (SDS) micelles. These mixed aggregates have a strong hydrophobic core, due to strong packing of both hydrophobic cores of Triton X-114 and SDS micelles, which is further enhanced by the addition of an electrolyte. These enhanced hydrophobic solubilising sites are used for efficient extraction of ammonium pyrrolidine dithiocarbamate (APDC) metal chelates at temperatures of 25–5 °C. This low temperature extraction avoids the thermal decomposition of these thermally labile complexes. The parameters affecting the extraction procedures are optimized. Under the optimized conditions, a pre-concentration factor of 10 was obtained with limits of detection of 5, 80, 30, 50 and 10 pg mL−1, respectively for Cd, Pb, Cu, Ni and Mn. The recoveries are in the range of 95–102% with 2–5% relative standard deviation. The accuracy of the procedure is evaluated by analyzing various certified reference materials such as BCR-713 final effluent, BCR-715 industrial effluent, BCR-609 ground water and NIST-1640a natural water matrices and also applied to real samples.

Application of mixed-micelle cloud point extraction for speciation analysis of chromium in water samples by electrothermal atomic absorption spectrometry

A simple mixed-micelle cloud point extraction procedure has been developed for speciation analysis of chromium in water samples by electrothermal atomic absorption spectrometry (ET-AAS). A mixed micelle consisting of sodium dodecyl sulfate (SDS) and Triton X-114 is used as an extracting agent. Cr(VI) was complexed with 1,5 diphenyle carbazid (DPC) in an HCl medium and it was concentrated in the surfactant rich phase after phase separation. Total chromium is subjected to a similar extraction procedure after oxidation. Then Cr(III) has been calculated by subtracting Cr(VI) from the total chromium. The main factors affecting the mixed-micelle cloud point extraction, such as concentration of HCl, DPC, SDS and Triton X-114, equilibrium temperature and incubation time, were investigated in detail. Under the optimum conditions, a detection limit of 1 ng L − 1 with preconcentration factor of 92 was achieved. Also the relative standard deviation for five replicate determinations of 0.1 μg L − 1 Cr(VI) was 3.5%. The proposed method was successfully applied to speciation of Cr(III) and Cr(VI) in environmental water samples.

Mixed micelle-cloud point extraction for the analysis of penicillin residues in bovine milk by high performance liquid chromatography

A mixed micelle-cloud point extraction (MM-CPE) has been developed for the analysis of penicillin antibiotics (ampicillin, penicillin G, oxacillin, and cloxacillin) in milk samples using Triton X-114 (TX-114) and cethyl trimethylammonium bromide (CTAB) as the mixed micellar extractant. The parameters affecting the MM-CPE that were investigated including solution pH, CTAB concentration, TX-114 concentration, electrolyte salt, equilibration temperature and incubation time. The optimum MM-CPE conditions were: 10 mmol L(-1) phosphate buffer pH 8, 0.06% (w/v) CTAB, 1.5% (w/v) TX-114, and 7% (w/v) Na(2)SO(4), and 5 min equilibration at 40 degrees C. The separation of penicillins was achieved within 8 min under the HPLC conditions: a Vydac C(18) column, isocratic elution of 5 mmol L(-1) phosphate buffer (pH 6.6) and methanol (55:45, v/v), and a flow rate of 1 mL min(-1), with photodiode array detection at 215 and 244 nm. Under the selected condition, the proposed method gave linear calibrations in the range 0.002-10 microg mL(-1) with correlation coefficients greater than 0.999. Limits of detection (LOD) were 2-3 ng mL(-1), and 15-40-fold enhancement compared to that without preconcentration. Good reproducibility was achieved with relative standard deviation <5% for peak area and <3% for retention time. High accuracy, with recoveries higher than 80%, was obtained. The proposed mixed micelle-CPE-HPLC method has shown to be of high potential for the analysis of penicillin residues in milk with LOD comparable to the established maximum residue limits (4-30 ng mL(-1)).

Ultra-trace speciation analysis of thallium in environmental water samples by inductively coupled plasma mass spectrometry after a novel sequential mixed-micelle cloud point extraction

Download options Please wait... Article information DOI https://doi.org/10.1039/B718149C Article type Paper Submitted 23 Nov 2007 Accepted 14 Jan 2008 First published 25 Feb 2008 Download Citation J. Anal. At. Spectrom., 2008,23, 555-560 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions Ultra-trace speciation analysis of thallium in environmental water samples by inductively coupled plasma mass spectrometry after a novel sequential mixed-micelle cloud point extraction N. N. Meeravali and S. Jiang, J. Anal. At. Spectrom., 2008, 23, 555 DOI: 10.1039/B718149C To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Social activity Tweet Share Search articles by author Noorbasha N. Meeravali Shiuh-Jen Jiang

Microwave assisted mixed-micelle cloud point extraction of Au and Tl from environmental samples without using a chelating agent prior to ICP-MS determination

A rapid microwave assisted mixed-micelle cloud point extraction procedure is developed for the pre-concentration and separation of ultra trace levels of Au and Tl simultaneously from environmental samples prior to their determination by ICP-MS. The method is based on the formation of extractable complexes of anionic species AuCl4− and TlCl32− with solubilizing cationic and hydrophobic sites of mixed-micelles, in the presence of HCl. The mixed-micelles consisting of cetyltrimethylammonium bromide (CTAB) and Triton X-114 are used for pre-concentration and extraction of formed extractable complexes of Au and Tl from a bulk aqueous phase into a small surfactant-rich phase, avoiding the addition of an external chelating agent. The phase separation is induced by microwave irradiation. The potential oxide interferences of Ta and Hf are eliminated effectively up to 2 and 5 μg mL−1 levels, respectively, enabling interference free determination of mono isotopic 197Au. The main parameters affecting the cloud point extraction process are evaluated and optimized. Under the optimized conditions, the pre-concentration factors and limits of detection are 125 and 110, and 0.12 and 0.02 pg mL−1, respectively, for Au and Tl. The recoveries of analytes are in the range of 97–103% at 10–40 pg mL−1 for Au and Tl with relative standard deviations of 0.5–2.2%. The accuracy of the procedure is validated by analyzing certified reference materials such as NIST SRM 1643c and 1643d (Trace elements in water), 2709 (San Joaquin soil) and 2711 (Montana soil), and NRCC NASS-5 (Open ocean seawater), as well as being applied to tap and seawater samples.

On-line sorption preconcentration of metals based on mixed micelle cloud point extraction prior to their determination with micellar chemiluminescence: Application to the determination of chromium at ng l −1 levels

The on-line incorporation of cloud point extraction (CPE) to flow injection analysis (FIA) is modified to extract and preconcentrate metal species rapidly, avoiding the formation of hydrophobic complexes, using a mixed micellar medium. Coupling the procedure with chemiluminescence (CL) detection based on the catalytic activity of metal species on the luminol–hydrogen peroxide reaction and enhancing the signal with the presence of a micellar carrier containing bromide ions produces a powerful tool for the preconcentration and determination of metal species at ng l −1 levels. As an analytical demonstration ultratrace concentrations of chromium were conveniently detected and quantified in samples with a complex matrix such as seawater and wastewater. The figures of merit for the determination of chromium were: 0.9–1.6% R.S.D. ( n=5) with detection and quantification limits 0.5 and 2.0 ng l −1, respectively. The calibration graph was rectilinear from 2 to 200 ng l −1 ( r=0.9996, n=6). Several other metal ions were determined in ideal situations, with analogous results.