Cloud Point Extraction For Preconcentration Research Articles

Development of Cloud Point Extraction for Preconcentration and Spectrophotometric Determination of Entecavir as Antiviral Drug in Pharmaceutical Formulations and Application to Content Uniformity Testing

Development of Cloud Point Extraction for Preconcentration and Spectrophotometric Determination of Entecavir as Antiviral Drug in Pharmaceutical Formulations and Application to Content Uniformity Testing

An Eco-Friendly Cloud Point Extraction for Preconcentration of Iron(III) in Water Samples prior to Spectrophotometric Determination

An Eco-Friendly Cloud Point Extraction for Preconcentration of Iron(III) in Water Samples prior to Spectrophotometric Determination

Surface-Active Ionic Liquid-Assisted Cloud Point Extraction for Pre-Concentration and Determination of Cobalt Ions in Pharmaceutical Preparations.

Herein we describe an efficient, simple, and precise micelle-mediated microextraction strategy based on the aggregation behavior of surface-active ionic liquids (SAILs) for the preconcentration and determination of cobalt ions in pharmaceutical preparations. Unlike the commonly used hydrophobic ionic liquids in IL-based microextraction methods, a water-soluble surface-active ionic liquid [1-hexadecyl 3-methylimidazolium chloride (C16MeImCl)] was used. A modified cloud point extraction (CPE) procedure based on the C16MeImCl-Triton X-114 mixed micellar system was proposed as an efficient extracting phase. A comparison of the analytical features of the extraction process with and without SAILs revealed the benefits of the proposed method. Advantages such as a wider linear range, lower detection limit, higher reproducibility, and improved extraction efficiency highlighted the proposed method over the conventional CPE method. These attractive specifications are due to the higher extraction efficiencies achieved in the presence of the SAIL and its favorable effects at the phase separation stage. Various parameters affecting the extraction efficiency were optimized by univariate and multivariate (Box-Behnken design) approaches. The calibration curve was obtained in the optimal experimental conditions with a linear range from 0.01 to 5.5 mg L-1 of cobalt ion concentration (R = 0.9992) and a detection limit of about 0.005 mg L-1. The RSD% for 10 replicate determinations of 1.0 mg L-1 Co was 0.9%. The proposed method was successfully applied to determine cobalt ions in vitamin B12 ampoules and tablets.

Using Cloud Point Extraction for Preconcentration and Determination of Iron, Lead, and Cadmium in Drinking Water by Flame Atomic Absorption Spectrometry

The determination of heavy metals in drinking water is an important assessment for quality as well as for the detection of pipeline corrosion. The aim of this research was to develop a simple, low cost, and accurate method based on cloud point extraction for the preconcentration and determination of iron, lead, and cadmium by flame atomic absorption spectrometry (FAAS) when the metal concentration in the sample is below the limit of detection without enrichment. By utilizing both 2,4-diamino-6-phenyl-1,3,5-triazine (DPT) and 3-amino-7-dimethylamino-2-methylphenazine (Neutral Red, NR) as chelating agents, and using Triton X-114 as the surfactant, lead, cadmium, and iron were concentrated in water samples prior to determination. The preconcentration was optimized by varying experimental factors, including the temperature, pH, and the concentrations of the chelating agents and surfactant. Using the optimized conditions, this novel procedure allows the determination of these trace elements with a 20-fold reduction in the detection limit with recoveries as high as 99%. The good reproducibility of the results demonstrates that this method was successfully applied to the determination of iron, lead, and cadmium in water samples by FAAS.

Cloud Point Extraction for Pre-Concentration and Spectrophotometric Determination of Trace Amounts of Silver Ions

During the last years, the cloud point extraction was applied for determination, separation, and enrichment of the elements. The current study used cloud point extraction (CPE) for the extraction of Ag(I) ions pre-concentration from watery solutions by a non-ionic surfactant (Triton X-114) and chelating agent a 6-(4-bromo-phenylazo)m-anisidine[6-(4-BrPAA)], then estimation by using the spectrophotometry at 514 nm. Several condition effects on the efficiency of the cloud-point extraction included Triton X-114 concentration, [6-(4-BrPAA)] concentration, pH, time, and incubation temperature. The silver reacts with [6-(4-BrPAA)] to produce complex at a ratio of one to one. 0.009 to 1.5 μg mL-1 is the range of linearity. The detection limit and quantification of Ag(I) ion were 0.0054 and 0.0182 μg mL-1, respectively. The interference of the cations was examined. The cloud-point extraction was used for the evaluation of silver concentration in the water specimen.

Application of cloud point extraction for preconcentration, separation and determination of Aluminum in food samples

Application of cloud point extraction for preconcentration, separation and determination of Aluminum in food samples

Application of ultrasound-assisted cloud point extraction for preconcentration of antimony, tin and thallium in food and water samples prior to ICP-OES determination

This study reports a simple, rapid and greener method based on ultrasound assisted-cloud point extraction coupled with inductively coupled plasma-optical emission spectroscopy (ICP-OES) for preconcentration and determination of antimony (Sb), tin (Sn) and thallium (Tl) in food and water samples. Factors affecting the preconcentration procedure were optimized using fractional factorial design and response surface methodology based on Box-Behnken design. Under optimum conditions, the calibration graphs were linear over the concentration range of 0.023–700 μg L−1 with correlation coefficients up to 0.9994, the limits of detection ranged from 0.007–0.010 μg L−1, the limits of quantification were from 0.023 to 0.033 μg L−1 and the relative standard deviations (n = 15) were between 1.3% and 4.1%. In addition, the preconcentration factors were found to be 150, 145 and 160 for Sb, Sn and Tl, respectively. Finally, the developed method was successfully applied in various food and water samples as well as certified reference materials for rapid determination of Sb, Sn and Tl.

Speciation and Determination of Low Concentration of Iron in Beer Samples by Cloud Point Extraction

A laboratory experiment is described in which students determine the concentration and speciation of iron in beer samples using cloud point extraction and absorbance spectroscopy. The basis of determination is the complexation between iron and 2-(5-bromo-2- pyridylazo)-5-diethylaminophenol (5-Br-PADAP) as a colorimetric reagent in an aqueous micellar solution followed by cloud point extraction for preconcentration. Total iron and Fe(II) were determined with and without addition of ascorbic acid as a reducing agent, respectively. The determination of iron concentration in real beer samples using cloud point extraction provides an opportunity for students to become familiar with preconcentration, complexation chemistry, masking agents, and the speciation of an analyte. Students also gain hands-on experience with adapting methods from scientific literature, using absorbance spectroscopy, and exploring quality control techniques, such as method detection limits and spike recovery.

Cloud-Point Extraction for Preconcentration and Platinum Determination Using Spectrophotometry in Environmental Samples

The present work outlines novel, simple and sensitive method to determine platinum using spectrophotometry after separation and preconcentration by cloud point extraction. The methodology was successfully applied for platinum determination using synthesized reagent 5-(2′,4′-dimethylphenylazo)-6-hydroxy-pyrimidine-2,4-dione (DMPAHPD), as complexing agent and Triton X-100 added as nonionic surfactant, respectively. Variable parameters such as pH, concentration of the reagent and Triton X-100, equilibrating temperature and centrifuging time were studied to enhance the sensitivity and extraction efficiency of the proposed method. Under optimum conditions the detection limit was found as 0.9 ng mL−1 for platinum in different environmental matrices. The present method was successfully applied for the determination of platinum in vegetable, soil, water, catalysis and ore samples. The results show good agreement with reported methods.

Cloud point extraction for preconcentration of trace beryllium and chromium in water samples prior to electrothermal atomic absorption spectrometry

In the present work, a simple, sensitive method was developed for the determination of beryllium and chromium by electrothermal atomic absorption spectrometry (ETAAS) after simultaneous pre-concentration by cloud point extraction (CPE). The procedure was based on the formation of the hydrophobic chelates of Be and Cr(III) and/or Cr(VI) with cupferron, followed by their quantitative extraction into the surfactant-rich phase by the Triton X-114. The effects of the main parameters affecting the extraction recovery of CPE, such as pH of the sample solution, concentration of the chelating agent and surfactant, equilibration temperature and incubation time, were investigated and optimised. Under the optimal experimental conditions, the limits of detection and limits of quantification for Be were 0.33 and 1.11 pg and for Cr(VI) were 0.98 and 3.28 pg, respectively. The pre-concentration factor for Be and Cr(VI) was found to be 20 for 10 mL of the water sample. The accuracy of the method was confirmed by analysis of certified reference materials of waters (“Trace Metals in Drinking Water” and SRM 1643e “Trace Elements in Water”) with satisfactory results. The method developed was successfully applied to the pre-concentration and determination of trace quantities of beryllium and chromium(VI) in different natural waters.