Emulsification Microextraction Method Research Articles

Development of an Ultrasound-Assisted Emulsification Microextraction Method for the Determination of Volatile Compounds in Wines

A fast and simple method based on ultrasound-assisted emulsification microextraction (USAEME) was developed for the analysis of volatile compounds in wines. A full factorial 24 screening design was built to investigate the main factors affecting the extraction of volatile components, namely the volume of extraction solvent, sonication time, salt content, and pH. Then, the factors with significant effects were optimized using an I-optimal design. The optimal value for all the variables studied was reached under the following experimental conditions: volume of extraction solvent 200 μL and salt content 5% m/v. The suitability of the optimized method was evaluated, resulting in very good linearity with coefficients of determination (R2) higher than 0.995 in all cases, while repeatability was lower than 8.4% except for d-limonene and p-cymene. Recoveries higher than 82% were observed for the groups of ethyl esters, acetate esters, alcohols, and terpenoid alcohols (linalool, α-terpineol). The recovery of acids ranged from 70.5% to 88.9%, whereas the three monoterpenes studied (d-limonene, γ-terpinene, p-cymene) were not extracted satisfactorily. The proposed method was effectively applied for the analysis of volatile compounds in laboratory-scale fermentations with selected strains of Saccharomyces cerevisiae.

A natural hydrophobic deep eutectic solvent-based microextraction method integrated with a spectrofluorimetric technique for the determination of daclatasvir as a direct-acting hepatitis C antiviral drug in plasma samples

An ultrasound-assisted emulsification microextraction method based on a natural hydrophobic deep eutectic solvent (USAEME-HDES) was developed for extraction and preconcentration of daclatasvir, a hepatitis C virus inhibitor, from plasma samples prior to spectrofluorimetric measurement. To make the deep eutectic solvent (DES) compatible with the fluorescence device, fatty acids were used as components of DES that can simultaneously act as hydrogen bond donors (HBD) and hydrogen bond acceptors (HBA). Various parameters, such as the solvent effect on the fluorescence spectrum and the composition and ratio of DES, were investigated and optimized. Other parameters, including pH, DES volume, sonication time, and NaCl concentration, were investigated and optimized using the central composite design combined with the desirability function. Under optimal conditions, compared to other methods, this method had a wide linear range (5–600 ng/mL) with a good coefficient of determination (0.9985) and a low limit of detection (1.42 ng/mL). Drug analysis results in the plasma samples showed that the method has good accuracy. Finally, the Green Analytical Procedure Index (GAPI) tool was used to evaluate the greenness of the method, which demonstrates our method's superior eco-friendship in comparison to other reported methods.

Ultrasound-Assisted Emulsified Microextraction Based on Deep Eutectic Solvent for Trace Residue Analysis of Metribuzin in Urine Samples

Deep eutectic solvent was used as extraction solvent to develop and optimize a new sample preparation method for the determination of metribuzin in urine samples. In order to determine the optimal values of the effective factors in the deep eutectic solvent-based ultrasound assisted emulsification microextraction method, six effective parameters were selected. The design of experiments was performed using the onevariable- at-a-time method. Totally, 96 experimental runs were performed, and the samples were analyzed using high-performance liquid chromatography with a UV detector. Under the optimum conditions, the calibration curve for metribuzin was linear in the concentration range of 5 to 500 μg L-1 for urine samples. The accuracy and reproducibility of the introduced method were determined using the relative recovery (RR %) and relative standard deviation (RSD %) tests on the fortified urine samples. RR % and RSD % were found to be 96.3 – 101.7 % and 3.2 – 7.6 %, respectively. The limit of quantification and the limit of detection were obtained 5 and 0.8 μg L-1, respectively.

Simple Emulsification Microextraction for the Preconcentration of Palladium in Water Samples by Flame Atomic Absorption Spectrometry

A simple and selective emulsification microextraction (EME) method in conjunction with flame atomic absorption spectrometry (FAAS) is reported for the preconcentration of palladium ions in aqueous solution. In this approach, N-(3-chloro-4-fluorophenyl)-N-phenylthiourea (CFPT) was synthesized for the first time for the complexation of metal ions including manganese, nickel, cadmium, cobalt, copper, gold, lead, palladium, iron, zinc, aluminum, and chromium and platinum with the microextraction method. The new CFPT ligand provided excellent selectivity toward Pd2+ ions in highly acidic conditions. The formation of a palladium hydrophobic compound with the new synthesized ligand was extracted into chloroform by shaking a model solution for a few seconds. The cloudy solution was centrifuged and the organic phase containing Pd2+ was diluted with nitric acid and transferred for the monitoring of the palladium absorbance by FAAS. Under the optimum conditions, the linearity (R 2 = 0.9986) was in the range from 10 to 1000 µg L−1 and the limit of detection was 2.28 µg L−1 for Pd2+. The developed EME-FAAS method was successfully applied for preconcentration and determination of Pd2+ in spiked samples such as well, stream, tap and sea water with good recoveries.

Efficacious and environmentally friendly deep eutectic solvent-based liquid-phase microextraction for speciation of Cr(III) and Cr(VI) ions in food and water samples

ABSTRACT A rapid, sensitive, and environmentally friendly air-assisted emulsification microextraction based on a deep eutectic solvent was developed for speciation of trace amounts of Cr6+ and Cr3+ ions in real samples. 1-(2-pyridylazo)-2-naphthol was used as a complexing agent and the decomposable and environmental friendly choline chloride-phenylethanol extraction solvent (ChCl:Ph-EtOH) was used as the extraction solvent. The resulting hydrophobic complex, i.e. Cr3+-1-(2-pyridylazo)-2-naphthol, was extracted into the extraction solvent by the air-assisted emulsification microextraction method, followed by its determination with flame atomic absorption spectrometry (FAAS). Different parameters affecting the extraction efficiency, including pH of the sample solution, ratio of the complexing agent to the analyte, number of extraction cycles and volume of the extraction solvent, were optimised using response surface methodology based on the central composite design (RSM-CCD). Under the optimum experimental conditions, the calibration curve was linear in the range of 1.0–300.0 ng mL−1 Cr3+ with a correlation coefficient of 0.997. The relative standard deviation (RSD) based on five replicate analyses of 200.0 ng mL−1 of Cr3+ ions was 4.7%, the limit of detection was 0.4 ng mL−1 (n = 5) and the preconcentration factor (PF) was 39. In order to check the applicability of the method, the chromium ions were determined in tap water and rice, as the model samples. Based on the results obtained, the proposed method was successfully used to determine the chromium species in different water and food samples.

A surfactant-based emulsification microextraction (SBEME) method for the atomic absorption determination of gold

A surfactant-based emulsification microextraction (SBEME) method for the atomic absorption determination of gold

Simple determination of amphetamine and methamphetamine in complicated matrices by filter‐based emulsification microextraction followed by high‐performance liquid chromatography

AbstractIn this work, a filter‐based emulsification microextraction method is combined with high‐performance liquid chromatography for a fast, simple, and efficient determination of amphetamine and methamphetamine in the human plasma and pharmaceutical wastewater samples. In this method, in order to enhance the extraction speed without the use of a disperser solvent, the extraction solvent is dispersed as fine droplets in the sample solution, and a filtration step completes the extraction process by separation of the extraction phase from the sample solution. This method is centrifuge‐free, provides a good sample clean‐up, and is totally accomplished in about 60 s. In order to achieve the optimal experimental conditions, the effective parameters involved including the type and volume of the extraction solvent, pH of the sample solution, and ionic strength are thoroughly examined. Under the optimized experimental conditions, the calibration curves were obtained in the range of 3–2000 ng mL−1. The relative standard deviations for the method were in the range of 7.1–9.2% and the limits of detection ranged between 1.0 and 1.5 ng mL−1.

Development of a new emulsification microextraction method based on solidification of settled organic drop: application of a novel ultra-hydrophobic tailor-made deep eutectic solvent

In this research, a new microextraction method based on the solidification of settled organic drop (SSOD) was developed by coupling a novel tailor-made ultra-hydrophobic deep eutectic solvent (DES) with effervescence assisted emulsification microextraction.

Determination of ochratoxin A in fruit juice by high-performance liquid chromatography after vortex-assisted emulsification microextraction based on solidification of floating organic drop.

A rapid, simple, and green vortex-assisted emulsification microextraction method based on solidification of floating organic drop was developed for the extraction and determination of ochratoxin A (OTA) with high-performance liquid chromatography. Some factors influencing the extraction efficiency of OTA such as the type and volume of extraction solvent, sample pH, salt concentration, vortex time, and sample volume were optimized. Under optimized conditions, the calibration curve exhibited linearity in the range of 50.0-500ngL-1 with a coefficient of determination higher than 0.999. The limit of detection was 15.0ngL-1. The inter- and intra-assays relative standard deviations were in a range of 4.7-8.7%. The accuracy of the developed method was investigated through recovery experiments, and it was successfully used for the quantification of OTA in 40 samples of fruit juice.

Combination of magnetic dispersive micro solid-phase extraction and supramolecular solvent-based microextraction followed by high-performance liquid chromatography for determination of trace amounts of cholesterol-lowering drugs in complicated matrices.

A novel, efficient, rapid, simple, sensitive, selective, and environmentally friendly method termed magnetic dispersive micro solid-phase extraction combined with supramolecular solvent-based microextraction (Mdμ-SPE-SSME) followed by high-performance liquid chromatography (HPLC) with UV detection is introduced for the simultaneous microextraction of cholesterol-lowering drugs in complicated matrices. In the first microextraction procedure, using layered double hydroxide (LDH)-coated Fe3O4 magnetic nanoparticles, an efficient sample cleanup is simply and rapidly provided without the need for time-consuming centrifugation and elution steps. In the first step, desorption of the target analytes is easily performed through dissolution of the LDH-coated magnetic nanoparticles containing the target analytes in an acidic solution. In the next step, an emulsification microextraction method based on a supramolecular solvent is used for excellent preconcentration, ultimately resulting in an appropriate determination of the target analytes in real samples. Under the optimal experimental conditions, the Mdμ-SPE-SSME-HPLC-UV detection procedure provides good linearity in the ranges of 1.0-1500 ng mL-1, 1.5-2000 ng mL-1, and 2.0-2000 ng mL-1 with coefficients of determination of 0.995 or less, low limits of detection (0.3, 0.5, and 0.5 ng mL-1), and good extraction repeatabilities (relative standard deviations below 7.8%, n = 5) in deionized water for rosuvastatin, atorvastatin, and gemfibrozil, respectively. Finally, the proposed method is successfully applied for the determination of the target analytes in complicated matrices. Graphical Abstract Mdμ-SPE-SSME procedure.

Binary-solvent-based ionic-liquid-assisted surfactant-enhanced emulsification microextraction for the determination of four fungicides in apple juice and apple vinegar.

A binary-solvent-based ionic-liquid-assisted surfactant-enhanced emulsification microextraction method was developed for the separation/preconcentration and determination of four fungicides (pyrimethanil, fludioxonil, cyprodynil, pyraclostrobin) in apple juice and apple vinegar. A nonchlorinated solvent amyl acetate, which has a lower density than water, was used as the extraction solvent, and an ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate, which has a high density and low toxicity, was used as a secondary solvent mixed with the extraction solvent. After centrifugation, the binary solvent drop with a relatively high density was deposited on the bottom of the tube. Some parameters influencing the extraction efficiency of analytes such as type of extraction solvent, ratio of ionic liquid, volume of mixed solvent, type and concentration of surfactant, sample pH, NaCl concentration, and vortex time were investigated and optimized. Under the optimized conditions, the proposed method provided a good linearity in the range of 5-200 μg/L. The limits of quantification of the method were in the range of 2-5 μg/L. The relative standard deviations for interday assays were 1.7-11.9%. The method was applied to the determination of pyrimethanil, fludioxonil, cyprodynil, and pyraclostrobin in apple juice and apple vinegar samples, and the accuracy was evaluated through recovery experiments.

Polytetrafluoroethylene physisorption-assisted emulsification microextraction as a cleanup and preconcentration step in the gas chromatography determination of aliphatic hydrocarbons in marine sediment samples.

For the first time, the application of polytetrafluoroethylene powder as an extractant phase collector or holder in liquid-phase microextraction has been developed. For this purpose, the analytical performances of two different ways of applying polytetrafluoroethylene powder in microextraction methods including polytetrafluoroethylene physisorption-assisted emulsification microextraction and dispersive liquid-phase microextraction via polytetrafluoroethylene extractant phase holders have been compared for analysis of aliphatic hydrocarbons in aqueous phases. Under the same conditions, the former showed better extraction efficiencies over the latter and as a result, it was applied as preconcentration and cleanup step in the analysis of aliphatic hydrocarbons in sediment samples followed by gas chromatography analysis. The linearity of the polytetrafluoroethylene physisorption-assisted emulsification microextraction method was obtained over a range of 3.7 and 2000 ng/g (R2 > 0.993). The relative standard deviations were less than 6.5% (n = 3). The limits of detection and quantification obtained by this method were 1.1-9.0 and 3.7-30 ng/g, respectively, indicating that satisfactory results were achieved by the procedure.

Development of a Microextraction Method Based on Dissolved Carbon Dioxide Flotation after Emulsification for the Determination of Triazole Pesticides Residues in Water Samples by Gas Chromatography-Mass Spectrometry.

A novel dissolved carbon dioxide flotation after emulsification microextraction (DCF-EME) method was proposed for the determination of four triazole pesticides in water samples coupled with gas chromatography-mass spectrometry (GC-MS) in a home-made glass round flask. The DCF-EME method is based on a rapid and simple phase separation of low-density organic solvent (toluene) from the aqueous phase via introducing a saturated NaHCO3 solution into the acidified sample (0.1 mol L-1 HCl); then analytes were extracted in toluene. Various parameters affecting the extraction process were optimized. Under the optimal conditions, the recoveries for four pesticides ranged from 82.8 to 121.2%. Meanwhile the limits of detection were at the range of 0.14 - 1.04 μg L-1, and the preconcentration factors were varied between 342 and 473 for different triazoles. The method is simple, fast and environmentally friendly, being successfully applied for the determination of triazole pesticides in water samples.

Analysis of Malathion pesticide residues in rice samples using ultrasound-assisted emulsification-microextraction coupled to UV photoionization source ion mobility spectrometry

The present paper describes the validation of ultrasound-assisted emulsification-microextraction method followed by ion mobility spectrometry (IMS) for determination malathion pesticides. Ultrasound radiation was applied for accelerating the emulsification of microliter organic solvent in aqueous solutions and enhancing the microextraction efficiency. This preconcentration step combined with IMS detection provided a precise and accurate method for determination of trace amounts of malathion pesticides. The effect of parameters influencing the extraction efficiency such as sonication time, type of extraction solvent, extraction solvent volume, and salt concentration were investigated and discussed. Under the optimum conditions, enrichment factors was 270 with corresponding LOD of 4 μg/L. Linearity with a coefficient of estimation (r2) were >0.99 in the concentration level range of 6–750 μg/L for extraction of Malathion in water samples. The applicability of the proposed method was evaluated by determination of the residues of the investigated pesticide in rice paddy water gathered from four stations during 60 days after spraying (June 2014), and in storage rice samples in Mazandaran province, Iran.

Development of an ultrasound-assisted emulsification microextraction method for the determination of chlorpyrifos and organochlorine pesticide residues in honey samples using gas chromatography with mass spectrometry.

A simple, rapid, and efficient ultrasound-assisted emulsification microextraction method followed by gas chromatography mass spectrometry in selected ion monitoring mode was developed for the determination of organochlorine pesticides in honey samples. The type and volume of organic extraction solvent, pH, effect of added salt content, and centrifuging time and speed were investigated. Under the optimum extraction conditions, 30 μL of 1, 2-dibromoethane (extraction solvent) was immersed into an ultrasonic bath for 1 min at 40°C. The limits of detection and quantification for all target pesticides were 0.003-0.06 and 0.01-0.2 ng/g, respectively. The extraction recovery was 91-100% and the enrichment factors were 168-192. The relative standard deviation for the method was <6% for intraday (n = 6) and <8% for interday precision (n = 4). The proposed method was successfully applied for the analysis of organochlorine pesticides in honey samples.

Ultrasound-assisted temperature-controlled ionic liquid emulsification microextraction coupled with capillary electrophoresis for the determination of parabens in personal care products.

We developed a CE and ultrasound-assisted temperature-controlled ionic liquid emulsification microextraction method for the determination of four parabens (methyl paraben, ethyl paraben, propyl paraben, and butyl paraben) in personal care products including mouthwash and toning lotion. In the proposed extraction procedure, ionic liquid (IL, 1-octyl-3-methylimidazolium hexafluorophosphate) was used as extraction solvent, moreover, no disperser solvent was needed. Parameters affecting the extraction efficiency including volume of IL, heating temperature, ultrasonic time, extraction time, sample pH, ionic strength, and centrifugation time were optimized. Under the optimized conditions, the method was found to be linear over the range of 3-500 ng/mL with coefficient of determination (R(2) ) in the range of 0.9990-0.9998. The LODs and LOQs for the four parabens were 0.45-0.72 ng/mL and 1.50-2.40 ng/mL, respectively. Intraday and interday precisions (RSDs, n = 5) were in the range of 5.4-6.8% and 7.0-8.7%, respectively. The recoveries of parabens at different spiked levels ranged from 71.9 to 119.2% with RSDs less than 9.5%.

Centrifuge-less Emulsification Microextraction Using Effervescent CO2 Tablet for On-site Extraction of PAHs in Water Samples Prior to GC–MS Detection

For the first time, centrifuge-less emulsification microextraction using effervescent CO2 tablet (EME-ECT) coupled with gas chromatography-mass spectrometry (GC–MS) is presented for the preconcentration and determination of polycyclic aromatic hydrocarbons (PAHs) in aqueous samples. In this method, after injection of a mixture of extraction and disperser solvents into the sample with volume of 90 mL, an effervescent tablet containing the effervescence precursors (sodium bicarbonate as carbon dioxide source and sodium dihydrogen phosphate as proton donor) was applied for phase separation. Thanks to the in situ generation of carbon dioxide, as a consequence of the effervescence reaction, the dispersed extraction solvent was collected at the surface of the aqueous sample and then was narrowed to the capillary part of a special home-made extraction cell for facile retrieval. The experimental variables, including volume of extraction and disperser solvents, ionic strength and weight of effervescent tablet, were investigated and optimized by a central composite design. Under the optimal conditions, the limits of detection were at the range of 0.01–0.1 µg L−1 and preconcentration factors were varied between 134 and 406 for different PAHs. As can be seen here, there is no need for centrifugation or a special apparatus for the proposed emulsification microextraction method and it can easily be applied for the analysis of large volumes of samples. Taking these advantages to account, EME-ECT has the most promise for becoming a quick, simple and economical approach to reduce transportation costs after water sampling in the field.

Ultrasound-assisted emulsification microextraction and preconcentration of trace amounts of silver ions as a cyclam complex

Silver has been recognized as a toxic element for biological systems. A low level of exposure to silver compounds is widespread owing to the use of soluble silver compounds to disinfect water for drinking and reaction purposes. The present paper describes an ultrasound-assisted emulsification microextraction method for the preconcentration and determination of silver ions in drinking water. Determination was carried out using 1,4,8,11-tetraazacyclotetradecane as a complexing reagent and chloroform as extracting solvent, followed by flame atomic absorption determination of silver ions. The main factors affecting microextraction efficiency, such as extraction solvent type and volume, concentration of chelating reagent, concentration of picrate ions, and pH, were optimized. Under optimal conditions, a limit of detection and enrichment factor of 6.79 ng mL−1 and 9.8 were obtained for silver ions, respectively. The analytical curve was linear in the range of 0.055–1.5 μg mL−1, with a correlation coefficient (R 2) of 0.997. The use of ultrasound as a powerful energy for the microextraction and determination of silver was proposed. The main advantages of the method are as follows: minimum use of toxic organic solvent and wide linear dynamic range.

Ionic liquid based microextraction of targeted lipids from serum using UPLC-MS/MS with a chemometric approach: a pilot study

An ionic liquid based vortex assisted surfactant-enhanced emulsification microextraction method followed by using liquid chromatography-electrospray mass spectrometry have been used for the determination of fatty acids, triglycerides and phospholipids in serum samples.

Tandem dispersive liquid–liquid microextraction as an efficient method for determination of basic drugs in complicated matrices

A simple and efficient approach is introduced for the improvement of the clean-up and applicability of the dispersive liquid–liquid microextraction (DLLME) method in complicated matrices. For this purpose, two dispersive microextraction methods were combined, and the tandem dispersive liquid–liquid microextraction (TDLLME) method was provided. At first, using the ultrasound-assisted emulsification microextraction (USAEME) method, the tricyclic anti-depressant (TCA) drugs nortriptyline, imipramine, and amitriptyline, as the model compounds, contained in an aqueous sample solution (8.0mL), were extracted into an organic solvent (35μL). Then by utilizing the air-agitated liquid–liquid microextraction (AALLME) method, these analytes were simply back-extracted into 50μL of an aqueous acceptor phase. By performing this convenient extraction method, a high sample clean-up was obtained; the overall extraction time was 7min. The back-extraction step could be performed in less than 2min, and very simple tools were required for this purpose. The response surface methodology (RSM) was used for the optimization of the experimental parameters so that the volumes 95 and 50μL were obtained for the organic solvent and the acceptor phase, respectively, and the pH values of 11.25 and 1.75 were obtained for the donor and acceptor phases, respectively, as the optimal extraction conditions. Under the optimized conditions, TDLLME-HPLC-UV provided a good linearity in the range of 2.5–5000ngmL−1, low limits of detection (0.7–1.0ngmL−1), good extraction repeatabilities (relative standard deviations below 6.2%, n=5), and enrichment factors (EFs) of 50–101. Finally, the developed method was successfully used for the determination of the mentioned drugs in the wastewater and human plasma samples.