Rapid Cloud Point Extraction Research Articles

A novel fast room-temperature cloud point extraction coupled to graphite furnace atomic absorption spectroscopy for Copper(II) traces determination

ABSTRACT A novel environmentally friendly rapid cloud point extraction at room temperature coupled to graphite furnace atomic absorption spectroscopy (RT-CPE-GFAAS) for Copper (II) traces quantification was developed. Were found the most optimal conditions for the instant surfactant rich phase of Triton X-100 formation and the extraction of Copper (II) as a complex with 6,7-dihydroxy-2-phenyl-4-methylbenzopyrylium perchlorate (DHMPhB) at room temperature immediately: addition of 0.5 mol L−1 H2SO4 solution to pH 4.5; 0.15 mol L−1 ammonium benzoate; 1.5 · 10–4 mol L−1 DHMPhB and 1 v/v.% Triton X-100. As a diluent for surfactant rich phase was used 2-propanol. The calibration plot constructed under the optimal conditions is linear in the range of Copper (II) concentrations of 0.31–127 μg L−1, and the limit of quantification and limit of detection are 0.31 and 0.09 μg L−1 respectively. The developed RT-CPE-GFAAS technique was successfully used to determinate Copper (II) traces in water samples with affordable results.

A rapid cloud point extraction of Molybdenum(VI) with 6,7-dihydroxy-2,4-diphenylbenzopyrylium perchlorate prior to its spectrophotometric determination

A novel and rapid cloud point extraction at room temperature (RT-CPE) for preconcentration of Molybdenum(VI) binded with 6,7-dihydroxy-2,4-diphenylbenzopyrylium perchlorate coupled with spectrophotometric detection was developed. The proposed technique includes the formation of red complex of Molybdenum(VI) with 6,7-dihydroxy-2,4-diphenylbenzopyrylium perchlorate (DHDPhB), its extraction at room temperature into chemically induced Triton X-100 surfactant-rich phase, and measurement of absorbance at 560 nm. Optimal RT-CPE conditions were found: 0.8% (v/v) of Triton X-100 and 0.04 M of sodium salicylate for initiating of RT-CPE; pH 1.8; 2.5·10–5 M of DHDPhB. The calibration plot is linear in the Molybdenum(VI) concentrations range of 7.9–160 μg L−1 and limit of detection is 2.3 μg L−1. The developed RT-CPE method has been successfully applied to spectrophotometric determination of Molybdenum(VI) traces in water and milk samples.

Non-aqueous phase hydride generation and determination of trace bismuth by atomic fluorescence spectrometry

Hydride generation (HG) of bismuth was accomplished in non-aqueous media by using solid reductant of potassium borohydride (KBH4) as a derivation reagent. The riched micelle phase of surfactant Triton X-114 was used as the non-aqueous media for the chemical vapor generation (CVG), and atomic fluorescence spectrometry (AFS) was used for the elemental determination. The analyte ions were firstly extracted into the non-aqueous media from the bulk aqueous phase of analyte/sample solution via a rapid cloud point extraction (RCPE) process and then directly mixed with the solid reductant KBH4 to generate volatile bismuth hydride in a specially designed reactor, which was then rapidly transported to a commercial atomic fluorescence spectrometer for detection. Under the optimal conditions, the limit of detection (LOD) for bismuth was 0.08μg/L. Compared to conventional HG-AFS, the efficiency of non-aqueous phase HG accomplished using solid reductant and the analytical performance of the developed method was considerably improved.

Development of a cloud-point extraction method for determination of trace amounts of copper(II) in water samples

A simple and rapid cloud-point extraction method by using a Schiff base extractant, named bis(2hydroxynaphthaldehyde)-1,2-propanediimine, is presented for preconcentration of trace amounts of copper ions in water samples, prior to the determination by flame atomic absorption spectrometry. The process is based upon the complexation of Cu(II) ions by the Schiff base. The formed complexes are soluble in a micellar phase composed by the non-ionic surfactant octylphenoxypolyethoxyethanol (Triton X-114), and then are extracted into the surfactant-rich phase at above its cloud-point temperature. The effect of parameters influencing the extraction efficiency, such as aqueous solution pH, concentration of the Schiff base, amount of the surfactant, equilibration temperature and incubation time were investigated and discussed. Under the optimum experimental conditions, the calibration plot was linear in the range 1–400 µg/L with a limit of detection 0.3 µg/L. A preconcentration factor of 20 was achieved by the presented method. The proposed method was successfully applied for the determination of copper in various water samples.

A cloud point extraction procedure for gallium, indium and thallium determination in liquid crystal display and sediment samples

A simple, sensitive and rapid cloud point extraction (CPE) methodology has been developed for the selective separation and preconcentration of gallium, indium and thallium, after complexation with gallic acid in the presence of Triton X-114 as a non-ionic surfactant.

Selective separation of palladium from synthetic highly active liquid waste by cloud point extraction using benzil mono-(2-pyridyl)hydrazone and Triton X-114

A simple and rapid cloud point extraction methodology has been developed for the separation and determination of palladium, after complexation with benzil mono-(2-pyridyl) hydrazone in acidic medium, using Triton X-114 as nonionic surfactant. Under the optimum experimental conditions, the calibration curve was linear in the range of 0.05–25 µg L−1. The enrichment factor was 104 for a 50 mL sample volume. The limits of detection, based on three times the standard deviation of the blank signal by seven replicate measurements was 0.12 µg L−1. The relative standard deviation (RSD) for seven replicate determination at 5 µg L−1 of palladium was 1.85 %. Under the presence of foreign ions and EDTA as a strong complexing agent, no significant interference was observed. The accuracy of the results was verified by analyzing spiked water samples. The proposed method has been applied for the separation and determination of palladium from synthetic highly active radioactive waste with satisfactory results.

Cloud point extraction of Pd(II), Au(III), and Ag(I) prior to their determination by graphite furnace atomic absorption spectrometry

A simple and rapid cloud point extraction methodology has been developed for the separation and preconcentration of palladium (Pd2+), gold (Au3+), and silver (Ag+) ions. The metal ions in the initial aqueous solution were complexed with 4-allylthiosemicarbazide, and Triton X-114 was added as surfactant. Dilution of the surfactant-rich phase with acidified metanol was performed after phase separation, and the metal ions were determined by graphite furnace atomic absorption spectrometry. The main factors affecting the cloud point extraction procedure, such as pH, concentration of the ligand, amount of Triton X-114, equilibrium temperature, and incubation time, were investigated and optimized. Under the optimum experimental, the calibration graphs were linear upto 100 μg L−1 for Pd2+ and Au3+ and up to 80 μg L−1 for Ag+. The enrichment factors were 48, 53, and 51 for Pd2+, Au3+, and Ag+, respectively. The limits of detection, based on three times the standard deviation of the blank signal by seven replicate measurements, were 0.15, 0.07, and 0.04 μg L−1 for Pd2+, Au3+, and Ag+, respectively. The accuracy of the results was verified by analyzing spiked real samples (water, blood, and urine) as well as by comparison the results of geological samples with those obtained by ICP−MS after solvent extraction using ammonium pyrrolidinedithiocarbamate in methyl isobutyl ketone. The proposed method has been applied for the determination of the metal ions in real samples with satisfactory results.

Application of rapid cloud point extraction method for trace cobalt analysis coupled with spectrophotometric determination

In this work, the analytical performance of conventional spectrophotometer was improved through the coupling of effective preconcentration method with spectrophotometric determination. Rapidly synergistic cloud point extraction (RS–CPE) was used to pre-concentrate ultra trace cobalt and firstly coupled with spectrophotometric determination. The developed coupling was simple, rapid and efficient. The factors influencing RS–CPE and spectrophotometer were optimized. Under the optimal conditions, the limit of detection (LOD) was 0.6μgL−1, with sensitivity enhancement factor of 23. The relative standard deviation (RSD) for seven replicate measurements of 50μgL−1 of cobalt was 4.3%. The recoveries for the spiked samples were in the acceptable range of 93.8–105%.

Optimization of a new cloud point extraction procedure for the selective determination of trace amounts of total iron in some environmental samples

A new, simple, and rapid cloud point extraction (CPE) procedure system, combined with flame atomic absorption spectrometry (FAAS), was developed for selective separation, preconcentration, and determination of trace amounts of total iron in some environmental samples. The complexing agent, N,N'-(2,2'-(ethane-1,2-diylbis(oxy)) bis(ethane-2,1-diyl))bis(2-chloroacetamide) (EDBOCA), is selective at pH 5.0 for only Fe(II) and Fe(III) ions in the presence of Cu(II), Pb(II), Cd(II), Mn(II), Co(II), Cr(III), Cr(VI), Ni(II), Zn(II), Al(III), Mo(VI), Pd(II), Pt(IV), Au(III), and V(V) ions. The procedure is based on the complexation of Fe(III) ions with EDBOCA reagent in the presence of Triton X-114 (TX-114) as a non-ionic surfactant. The optimum conditions for the CPE of Fe(III) ions were investigated with respect to several experimental parameters such as pH of the solution, TX-114 and EDBOCA concentrations, incubation time and temperature, and centrifugation rate and time. The detection limit for Fe(III) ions based on the 3 times the standard deviation of the blanks (N:10) was found to be 1.22 \mu g L^{-1}, while the relative standard deviation (RSD) was 4.2%. Environment Canada TM-25.3 and CRM-SA-C Sandy Soil C, as certified reference materials, were used, and spike tests were applied to validate the method. The method was applied to some real environmental samples to evaluate their total iron levels.

Indirect Determination of Sulfadiazine by Cloud Point Extraction/Flow Injection‐Flame Atomic Absorption (CPE/FI‐FAAS) Spectrometry

AbstractAn indirect simple and rapid cloud point extraction is proposed for separation and preconcentration of sulfadiazine and its determination by flow injection‐flame atomic absorption spectroscopy (FI‐FAAS). The sulfadiazine from 35 mL of solution was readily converted to silver sulfadiazine upon addition of silver nitrate (9.7 × 10‐5 mol/L). Then, Triton X‐114 a non ionic surfactant was added and the solution was heated to 60 °C. At this stage, two separate phases was formed and silver sulfadiazine enters the surfactant rich phase of non‐ionic micelles of Triton X‐114. The surfactant‐rich phase (∼50 μL) was then separated and diluted to 300 μL with acidic methanol. The concentration of silver in the surfactant‐rich phase which is proportional to the concentration of sulfadiazine in sample solution was determined by FI‐FAAS. The parameters affecting extraction and separation were optimized. Under the optimum conditions (i.e. pH 2‐10, silver concentration (9.7 × 10 ‐5 mol/L), Triton X‐114 (0.075% v/v) and temperature 60 °C) a preconcentration factor of 117 and a relative standard deviation of 4.9% at 37 μg L‐1 of sulfadiazine was obtained. The method was successfully applied to analysis of milk, urine and tablet samples and accuracy was determined by recovery experiments.

Determination of Arsenic in Scalp Hair Samples from Exposed Subjects Using Microwave-Assisted Digestion With and Without Enrichment Based on Cloud Point Extraction by Electrothermal Atomic Absorption Spectrometry

A simple and rapid cloud point extraction (CPE) procedure was applied for preconcentration of trace quantities of arsenic (As) in scalp hair samples. The samples were subjected to microwave-assisted digestion in a mixture of nitric acid and hydrogen peroxide (2 + 1, v/v) prior to preconcentration by CPE. The As in digested samples was complexed with ammonium pyrrolidine dithiocarbamate (APDC), and the resultant As-PDC complex was extracted by a nonionic surfactant, octylphenoxypolyethoxyethanol (Triton X-114). After centrifugation, the surfactant-rich phase was diluted with 0.1 M HNO3 in methanol and analyzed by electrothermal atomic absorption spectrometry. The experimental parameters, i.e., amount of APDC, concentration of Triton X-114, equilibrium temperature and time, were optimized. For validation of the proposed method, a certified reference material (CRM) of human hair (BCR 397) was used. No significant difference (P > 0.05) was observed between the experimental results and certified values of the CRM (paired t-test). The LOD and LOQ obtained under the optimal conditions were 0.025 and 0.083 microg/kg, respectively. The developed method was applied for the determination of As in scalp hair samples from male and female subjects of two villages of Khairpur Mir's, Pakistan.