Cloud Point Extraction Method Research Articles

Development of Cloud Point Extraction for Parabens Using Different Surfactants with Modifiers

Abstract Cloud point extraction (CPE) is a simple, fast, inexpensive and environmental friendly methodology for preconcentration in extraction of trace organic pollutants from aqueous solutions. CPE has been developed and modified by various researcher to improve the method. This paper is review and compilation of the whole development and modification of CPE from the research group of Noorashikin Md Saleh from year 2013 to 2018 that focus on extraction of organic pollutant which is parabens (methylparaben, ethylparaben, propylparaben and benzylparaben). Modification done by using different surfactants (Sylgard 309 and DC193C) and adding modifier (β-cyclodextrin) into the CPE method and to compare the effectiveness of the modification. The preconcentration and extraction is analysed using analytical instruments such as ultra-violet spectrometry (UV-Vis) or high performance liquid chromatography coupled with ultra-violet spectrometry (HPLC-UV). Each developed method will have parameters optimization such as effect of salt concentration, surfactant and modifier concentration, temperature, pH and extraction time. Each successful development and modification of methodology is validated on various kind of samples such as water samples, beverages and cosmetic products. The limit of detection for parabens extraction using CPE with Sylgard 309, DC193C and DC193C with β - cyclodextrin were 0.01 – 0.02 μg/L, 0.17–0.20 μg/L, and 0.017–0.027 μg/L respectively while the percentage recovery for water samples using CPE with Sylgard 309, DC193C and DC193C with β-cyclodextrin were 80.5–95.2%, 71.2–97.7% and 90.3–98.9% respectively. In addition, the percentage recovery for beverages using CPE with Sylgard 309 and DC193C were 76.4–117.4% and 80.9–106.4% respectively while the percentage recovery for cosmetics using CPE and Sylgard 309 were 69.6–112.8%. Throughout the research, it shows that CPE have potential to work with different surfactants in preconcentration for extraction of parabens from aqueous samples.

Cloud Point Extraction and Spectrophotometric Determination of Allura Red (E129) in Foodstuffs

A new cloud point extraction method was developed for preconcentration of allura red food dyeas a prior step to its spectrophotometric determination by UV-Vis spectrometry. Allura red was determined at 506nm. Extraction parameters such as H2SO4 and surfactant concentrations, equilibration time and temperature wereinvestigated and optimized. Interference efects of matrix components were investigated. Preconcentration factor ofthe method was obtained as 25. The relative standard deviations of the method were lower than 6%. Detection limitand quantitation limit of the method were determined as 3.0 and 8.5 ng mL-1, respectively. Linear calibration curvewas plotted in the range of 0-6 µg mL-1. Finally, the method was successfully applied to foodstuffs to determinethe allura red contents of energy drink, candy, drink powder, syrup and jelly samples. Allura red concentrations offoodstuffs were determined between 9-499 µg g-1 and 47-231 µg mL-1 for solid and liquid samples, respectively.

Evaluation of a cloud point extraction method for the preconcentration and quantification of silver nanoparticles in water samples by ETAAS

ABSTRACTA simple and reliable analytical method using instrumentation available in most of the laboratories has been developed for the separation and determination of silver nanoparticles in water samples. Cloud point extraction (CPE) was used for the separation of silver nanoparticles (AgNPs) from the sample and these nanoparticles were then determined by electrothermal atomic absorption spectrometry (ETAAS). Parameters related to the cloud point extraction procedure (Triton X-114 concentration, type of complexing agent (EDTA or Na2S2O3), pH, incubation temperature, incubation and centrifugation time) were selected using a multivariate approach (designs of experiments); 8.6% (v/v) Triton X-114, 750 µL saturated EDTA and pH 7 were selected as the optimum conditions. Calibration standards in a concentration range from 0 to 10 µg L−1 of AgNPs were subjected to the CPE procedure to obtain quantitative recoveries. The LOD and LOQ were 0.04 and 0.13 µg L−1, respectively. The method is selective for the extraction of AgNPs, and ionic Ag remains in the aqueous phase. Single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) was used to evaluate the effect of the CPE procedure in particle size, and no changes were observed. Finally, the procedure was applied to wastewater samples spiked with nanoparticles with quantitative recoveries.

Combination of sequential cloud point extraction and hydride generation atomic fluorescence spectrometry for preconcentration and determination of inorganic and methyl mercury in water samples

A sequential cloud point extraction method was established for the determination of trace mercury species in water samples by hydride generation atomic fluorescence spectrometry (HGAFS). The proposed extraction system consisted of two chief steps: isolation of inorganic mercury (Hg2+) by chelating with potassium-iodide and methyl green, and then isolation of methyl mercury (CH3Hg+) by chelating with ammonium pyrrolidinedithiocarbamate. The nonionic surfactant Triton X-114 was chosen as the extractant, while the brominating agent was applied to convert extracted CH3Hg+ into Hg2+. Before HGAFS detection, the two surfactant-rich phases obtained in the sequential process were separately diluted to 3 mL with 5% (v/v) HCl after the addition of antifoam (0.4 mL). The effects of experimental conditions, including pH and concentration of surfactant and chelating agents, on cloud point extraction were optimized. Under the optimum conditions, the limits of detection for Hg2+ and CH3Hg+ were 0.007 and 0.018 μg/L with the enrichment factors of 15.1 and 11.2, respectively. The proposed method was successfully used for the determination of trace Hg2+ and CH3Hg+ in water samples with satisfactory recoveries of 95–104%.

Determination of Trace Nickel in Water Samples by Graphite Furnace Atomic Absorption Spectrometry after Mixed Micelle-Mediated Cloud Point Extraction

A simple and sensitive cloud point extraction method for the preconcentration of ultra-trace amounts of nickel as a prior step to its determination by graphite furnace atomic absorption spectrometry was proposed. It is based on the reaction of nickel with 2-(5-bromo-2-pyridylazo)-5-dimethylaminoaniline (5-Br-PADMA) in HAc–NaAc buffer media and mixed micelle-mediated extraction of the complex using the anionic surfactant sodium dodecyl sulfate sodium (SDS) and non-ionic surfactant (1,1,3,3-Tetramethylbutyl)phenyl-polyethylene (Triton X-114). The optimal reaction and extraction conditions such as pH, concentration of 5-Br-PADMA, SDS and Triton X-114, equilibrium temperature, incubation, and centrifuge time were evaluated and optimized. Under the optimal conditions, the calibration graph was linear over the range 0.1–5.5 ng/mL of nickel with a correlation coefficient of 0.9942. The detection limit obtained was 0.031 ng/mL, and the relative standard deviation was 2.1% for nickel (c = 2 ng/mL, n = 6). The proposed method was successfully applied to the determination of nickel in water samples.

A simple Spectrophotometric Evaluation Method Of Allura Red (E129) in The several Samples Using Cloud Point Extraction

Cloud point extraction (CPE) method was successfully used for estimation and preconcentration of Allura red (E129) by spectrophotometry. The procedure was depended on the extraction of Allura red as an ion pair with cetyl pyridinium chloride from aqueous solution using a nonionic surfactant TX-114 or Brij-35. The absorbance of the extracted surfactant- rich phase was measured at 507 nm after diluted with water.The influence of different factors on cloud point extraction(CPE) of Allura red such as pH media ,equilibrium temperature ,incubation time , concentration of surfactant and electrolyte concentration was investigated.Calibration graph was linear in a concentration range between 2-40 µgml-1 of Allura red with correlation coefficient r= 0.9998 for TX-114 and 0.9992 for Brij-35 .The developed procedure was applied to estimation and preconcentration of Allura red in the different beverages

Preconcentration and Determination of Trace Nickel and Cobalt in Milk-Based Samples by Ultrasound-Assisted Cloud Point Extraction Coupled with Flame Atomic Absorption Spectrometry.

In this study, ultrasound-assisted cloud point extraction (UA-CPE) method was developed for the determination of Ni(II) and Co(II) in milk-based products. After extraction and preconcentration, the Ni(II) and Co(II) contents of samples were determined by flame atomic absorption spectrometry (FAAS). After their complexation with hydroxy naphthol blue (HNB) in the presence of cationic surfactant, CTAB at pH 4.0, the Ni(II) and Co(II) were taken within the micellar phase of nonionic surfactant, TX-114. The micellar phase containing the analytes were diluted to a volume of 0.7mL with 1.0-mol/L HNO3 in ethanol to reduce its viscosity and to facilitate sample treatment and then was analyzed by FAAS. The various analytical parameters affecting UA-CPE efficiency were investigated. The analytical features obtained after optimization are as follows: limits of detection are 0.56 and 0.78μg/L; sensitivity enhancement factors are 48.6 and 53.9; the calibration curves were linear 3-180 and 2-160μg/L for Co(II) and Ni(II), respectively, after preconcentration of 50-fold. The precision (as RSD%) between 1.8-3.6% and 2.2-3.8% (25 and 100μg/L, n = 5) for Ni(II) and Co(II), respectively. The accuracy was statistically verified by analysis of two certified reference material samples (CRMs), including recovery studies after spiking. The method was applied to the analysis of milk-based samples with satisfied results.

Separation, Preconcentration and Spectrophotometric Determination of Rhodamine B in Industrial, Cosmetic and Water Samples by Cloud Point and Solid Phase Extraction

The aim of this study is extraction, preconcentration and spectrophotometric determination of Rhodamine B (RB) in aqueous media by developing solid phase extraction (SPE) and cloud point extraction (CPE) methods. Amberlite XAD-1180 adsorbent and Tergitol NP-7 surfactant were used for SPE and CPE, respectively. Parameters of SPE and CPE which effected quantitative extractions were investigated and optimized. Matrix effects of some ions and dyes were analyzed at the optimum conditions. Developed methods were used to determine RB contents of anti-freeze, lipstick and water samples. The results of both methods demonstrated that the RB was quantitatively extracted and determined. RB contents of solid samples were found between 473 ± 15 and 317 ± 8 μg/g; 472 ± 11 and 312 ± 6 μg/L dye contents were determined for liquid samples. The methods were tested by analysis of spiked samples. Analytical characteristics of the methods were compared with each other and previously reported studies.

A new approach for separation and recovery of betaine from beet molasses based on cloud point extraction technique.

The aim of this work was to explore the possibility of the application of cloud point extraction (CPE) method in micelle media to recovery betaine from beet molasses. Response surface method was employed to assess the effects of surfactant concentration, molasses concentration, incubation time, pH, electrolyte concentration, mixing time, and surfactant type on efficiency of betaine recovery from beet molasses. Also, a mathematical model was developed to predict the effect of each variable and their interactions on the efficiency of betaine recovery. The model showed that best surfactant was Triton X-114 and under the optimum conditions, betaine recovery from beet molasses was achieved up to 80% when three CPE steps with total of 1.5% (w/v) of surfactant were used. Subsequently, betaine was recovered nearly 100% from surfactant rich phase after adjusting pH at 2.5 and re-incubation at 40°C. The results showed that the proposed method is suitable for extraction of betaine from beet molasses.

Recovery of phenolic compounds from table olive processing wastewaters using cloud point extraction method

Table olive processing wastewaters lead to large environmental problems mainly due to its relatively high phenolic content. In the present study, the Cloud Point Extraction (CPE) technique was used to preconcentrate the natural phenolic compounds from table olive processing wastewaters (TOPW) using three different nonionic surfactants: Genapol X-080, Triton X100 and Tween 80. The optimum conditions for the CPE of phenolic compounds were studied with respect to different experimental parameters, surfactant concentration, pH of the solution, equilibrium temperature and incubation time. The most appropriate conditions were found to be 10% of surfactant (w/v), a pH value of 2, a temperature of 70 °C and an equilibrium time of 30 min. The recovery factors of phenolic compounds from TOPW with one step CPE under optimized conditions were 62%, 65% and 68% using 10% of Tween 80, Triton X100 and Genapol X-080, respectively.

Spectrophotometric Determination of Sunset Yellow (E-110) in Powdered Beverages and Pharmaceutical Preparations After Cloud Point Extraction Method

In this study, for the first time Brij 58 was used for the spectrophotometric determination of sunset yellow (SY) (E-110) in pharmaceutical preparations and powdered beverages after cloud point extraction (CPE). Certain parameters such as pH, surfactant concentration, extraction time and temperature, centrifuge speed and salt concentration were optimized. Linear range in the optimum conditions was 0.01 – 4.00 mg mL-1 and the correlation coefficient was 0.9995. The limit of detection (LOD) and the limit of quantification (LOQ) of this method were 0.0078 mg mL-1 and 0.0261 mg mL-1, respectively.

Triton X-100/β-Cyclodextrin Cloud Point Extraction for Removal of Phenol Using Different of Sodium Salts as Inducing Phase Separation Agent

A simple and low-cost cloud point extraction (CPE) method was developed for the removal of phenol in water samples prior to its spectrophotometric detection. Two CPE methods; CPE-(TX/βCD)-NaOH and CPE-(TX/βCD)-Na2CO3 were developed based on Triton X-100/β-cyclodextrin (TX-100/β-CD) using electrolytes of sodium hydroxide (NaOH) and sodium carbonate (Na2CO3), respectively as inducing phase separation agents. The effects of parameters; electrolytes, surfactant, β-CD, and analyte concentrations, temperature, incubation time, and pH were evaluated in the context of extracting phenol from an aqueous media. Under optimized conditions, the CPE-(TX-βCD)-NaOH was selected to extract phenol from real water samples due to its superior performance vis-a-vis the CPE-(TX-βCD)-Na2CO3. The calibration curve was linear in the range of 1.0 mg L-1 to 3.0 mg L-1 of phenol, with a regression coefficient of 0.9855. The extraction efficiency in spiked and without spiked phenol in real water samples was in the range of 91.9 - 116.1 %. The results confirmed that the developed method can be applied satisfactorily to detect the presence of phenol in real water samples.

Ionic liquid-based cloud-point extraction of quercetin for its sensitive HPLC–UV determination in juice samples

An ionic liquid-based cloud-point extraction (IL-CPE) method was developed for the extraction of quercetin in juice samples before its determination by high-performance liquid chromatography (HPLC). 1-Butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) was used as the ionic liquid. The cloud-point extraction parameters such as sample pH, extraction temperature, extraction time, amount of ionic liquid, extraction volume, and salt concentration were carefully studied and optimized for the achievement of maximum extraction recovery. Under the optimized conditions, i.e., 20 min heating at 40 °C, 100 μL IL volume, pH 2.0, and no salt addition, a mean recovery of 92.5% and an enrichment factor of 20 were obtained for quercetin. Relative standard deviation of the method was 3.76% for 6 replicates, and the calculated detection limit (3σ) of quercetin was 0.002 mg L−1. The method, coupled to HPLC was successfully applied to the sensitive determination of quercetin in apple and gapes juice samples with quantitative recoveries.

Application of modified cloud point extraction method for the chromium speciation in artificial saliva extracts of different snuff products

A modified cloud point extraction method (m-CPE) was developed for the speciation of chromium species (Cr3+ and Cr6+) in artificial saliva extracts (ASE) of snuff products. In this method, Cr3+ was complexed with 8-hydroxyquinoline, which was trapped in nonionic surfactant (Triton X-114), prior to analyzed by electrothermal atomic absorption spectrometer (ETAAS). Whereas, the total extractable Cr was determined by reducing Cr6+ to Cr3+ using Na2SO3 as a reducing reagent. Several parameters were optimized for the developed m-CPE. Under the most favorable conditions, enrichment factor, enhancement factor and limit of detection for the proposed method were 60, 134 and 0.04μgL−1, respectively having relative standard deviation <5%. Health risks associated with the intake of total Cr in snuff products was also assessed. Estimated daily intake of Cr via sniffing 10g/day of dry and moist snuff products was found below the maximum tolerable daily intake whereas the calculated risk for cancer due to Cr was observed in the acceptable range of 10 E−6–E−4.

Simultaneous Determination of Vitamins B1 and B2 in Food Samples by Modified Cloud Point Extraction Method and HPLC-DAD

A preconcentration and determination method was developed for vitamins B1 (thiamin) and B2 (riboflavin) at trace amounts based on cloud point extraction (CPE) and HPLC analysis. As a new approach in this method, Ag(I) ion was used to increase the transferring of vitamin molecules to micelle medium. Then, the formed complexes between Ag(I) ions and vitamins were easily extracted to nonionic surfactant phase. Following phase separation by centrifugation, aqua phase was separated and then surfactant-rich phase was diluted with 300 μL of 0.1 M HCl in 50% methanol. Under the optimized conditions, linear calibration curves were obtained in the range of 4–400 ng mL−1 for thiamin and 1–500 ng mL−1 for riboflavin. The detection limits of method were calculated as 1.33 and 0.35 ng mL−1, respectively. The relative standard deviations were 2.90 and 2.20% for five replicate measurements at 100 ng mL−1 concentration level. The method was validated by the analysis of three certified reference materials (NIST 3280, BCR-485, and ERM-BD600) and recovery test. Finally, the method was applied to the determination of vitamins B1 and B2 in real samples, including baby foods, milk, and cereals.

Using Safranin T as a Charge Transfer-Sensitive Ion-Pairing Reagent in Ultrasound-Assisted Cloud Point Extraction: Determination of Bisphenol A in Selected Beverages.

In this study, a new ultrasonic-assisted cloud point extraction method coupled with spectrophotometry was developed to extract from and determine bisphenol A (BPA) in a sample matrix. The method is based on charge transfer-sensitive ion-pairing complex formation between BPA and Safranin T in the presence of nitrate in a micellar interface at pH 5.0. The variables affecting extraction efficiency were optimized. A good linear relationship with a significant sensitivity difference was obtained in the ranges of 2-40 and 2-120 µg/L with LODs of 0.54 and 0.38 µg/L after preconcentration with two different extractants, respectively. From a preconcentration of a 15 mL sample, a preconcentration factor of 60 was obtained. Due to the lack of a certified material compatible with the sample matrix, the method was validated by conducting intraday and interday accuracy and precision studies based on two spiked QC samples (with a recovery rate greater than 94% and an RSD ranging from 3.8 to 5.9%). Moreover, the beverage samples were analyzed by the standard addition method to control for possible matrix effects. BPA was detected in the range of 1.8-7.2 µg/L in beverages with Triton X-114, whereas the levels changed to a range of 1.8-7.3 µg/L with Triton X-45. In such a way not to create a threat, these levels were considerably lower than the specific migration limit set by the European Union.

A novel cloud point extraction method for separation and preconcentration of cadmium and copper from natural waters and their determination by flame atomic absorption spectrometry

A sensitive and simple cloud point extraction method was developed for simultaneous separation and preconcentration of cadmium and copper prior to their determination by flame atomic absorption spectrometry. 4-phenyl-3-thiosemicarbazide was used as complexing agent and the cadmium and copper complexes were extracted from the aqueous phase by Triton X-114 surfactant. The effects of parameters such as sample pH, ligand amount, concentration of surfactant, incubation temperature and time were optimized. For 20 mL of preconcentrated solution, the detection limits (3σ) were 0.20 and 0.49 μg L−1, and the enrichment factors were 20.7 and 19.9 for Cd(II) and Cu(II), respectively. In order to verify the accuracy of the developed method, certified reference materials (SLRS-5 river water and SPS-SW2 Batch 127 surface water) were analysed. Results obtained were in good agreement with the certified values. The proposed method was applied to tap water, river water and seawater samples with satisfactory results.

Application of ultrasonically modified cloud point extraction method for simultaneous enrichment of cadmium and lead in sera of different types of gallstone patients

A novel and greener ultrasonically assisted/modified cloud point extraction procedure for the simultaneous preconcentration of lead and cadmium in serum samples of different types of gallstone patients was developed. The chelates of the under study metals, formerly formed with 8-hydroxyquinoline, were extracted in the micelles of a nonionic surfactant prior to analysis by flame atomic absorption spectrometer (FAAS). After the arrival of the cloud point, the critical micellar mass produced was homogenously dispersed in the aqueous phase with the help of ultrasound energy. The reliability of the developed procedure was tested by relative standard deviation (% RSD), which was found to be <5%. The performance of the proposed procedure was checked by applying to certified reference material and spiking standard in real samples. All the experimental parameters were optimized. The developed procedure of Um-CPE was applied successfully for the analysis of the target heavy metals in serum samples of different types of gallstone patients and referents. The higher levels of the understudy metals were observed in the patients as compared to the referents but the levels of the both metal were found to be considerably higher in patients with pigmented gallstones.

A new ligandless cloud point extraction method for preconcentration of iron from natural water samples and FAAS detection

A simple, efficient and inexpensive ligandless cloud point extraction method was developed for the preconcentration of trace amounts of iron from natural water samples, followed by flame atomic absorption spectrometry detection. The proposed method is based on the extraction of Fe(III) ions at pH 7.0 using the non-ionic surfactant Triton X-114 without the addition of any chelating ligand. The effect of parameters influencing the extraction efficiency such as sample pH, concentration of surfactant, incubation temperature and time, concentration of NaCl and sample volume were investigated and optimized. The effect of potentially interfering ions on the recovery of iron was also examined. Under optimum conditions, the detection limit (3σ) was 0.95 μg L−1 for Fe using a sample volume of 10 mL. A preconcentration factor of 20 was achieved. The accuracy of the method was checked through the analysis of certified reference materials (SLRS-5 river water, SPS-SW2 Batch 127 surface water) and spiked water samples. The percentage recovery values for spiked water samples were between 92% and 101%.

Flow injection-based cloud point extraction of phosalone and ethion in seawater of Chabahar Bay and determination by high-performance liquid chromatography: study of use of carbon nanotube and nanofibers as a column filler in flow system

This study presents an easy and cost-effective flow-based cloud point extraction (CPE) method for determining partial amounts of two organophosphorus pesticides (phosalone and ethion) in seawater by HPLC–UV–Vis. In continues CPE methodology, the effect of the different column packing type such as carbon nanotube, polyacrylonitrile nanofiber and fiberglass on pesticide extraction was investigated. The Triton X-100 was utilized as nonionic surfactant, and moreover, effect of different parameters such as pH, temperature, extraction time, surfactant concentration, type and volume of the eluent solution on the extraction efficiency was optimized. Under optimum conditions, the figures of merit of the method for phosalone and ethion were obtained as: the enrichment factor (172 and 166), line range (0.8–300 and 0.5–300 µg L−1, R2 = 0.9973 and 0.9982), relative standard deviation in concentration of 200 µg L−1 (%RSD = %5.4 and %7.99, N = 5) and limit of detection (LOD = 0.24 and 0.14 µg L−1). The suggested method was successfully used for determination of phosalone and ethion in Chabahar Bay seawaters with satisfactory results.