Homogeneous Liquid-liquid Extraction Research Articles

Development of salt-induced homogeneous liquid-liquid extraction using a deep eutectic solvent performed in a narrow-bore tube for the extraction of Zn(II), Cu(II), and Cd(II) ions from honey samples.

In this study, a sample preparation procedure based on salt-induced homogeneous liquid-liquid extraction performed in a narrow-bore tube was used for the preconcentration and extraction of Zn(II), Cu(II), and Cd(II) ions from honey samples. To perform the procedure, a mixture of working solution containing sodium chloride, acetonitrile, and a synthesized deep eutectic solvent (as an extraction solvent) was transferred into a narrow tube filled with solid sodium chloride up to a specific level. As the solution flowed through the tube, tiny droplets of the extraction solvent were formed at the boundary between the solution and salt layer. The droplets moved upwards in the tube and eventually collected as a distinct layer on the top of the solution. The separated phase was removed and dispersed into ionized water. After centrifugation, tiny droplets of the extraction solvent containing the analytes were sedimented at the bottom of the tube. The concentrated analytes were measured using flame atomic absorption spectrophotometry. The linear ranges and extraction recoveries were obtained in the ranges of 1.5-100 μg kg-1 and 89.6-94.8%, respectively. The detection limits ranged from 0.35 to 0.48 μg kg-1. Low relative standard deviations (C = 10 μg L-1, n = 6) of 3.1, 2.8, and 3.4% for Zn(II), Cu(II), and Cd(II), respectively, were obtained. Finally, the optimized method was successfully used in determination of concentration of the selected heavy metal ions in various honey samples.

In-situ derivatisation, extraction, and preconcentration of some phenolic compounds from water and wastewater samples through cold-induced homogenous liquid-liquid extraction followed by dispersive liquid-liquid microextraction

ABSTRACT In this study, an efficient sample preparation method for the extraction and preconcentration of some phenolic compounds was developed before their analysis with gas chromatography equipped with a flame ionisation detector. Initially, cold-induced homogeneous liquid-liquid extraction was performed for the extraction of polar target compounds from petrochemical, pharmaceutical, well water, and city sewage samples. In the following for more preconcentration, dispersive liquid-liquid microextraction was carried out to enhance enrichment factors. For this purpose, in a glass test tube, a mixture of acetonitrile and acetic anhydride (derivatisation agent) was added to the sample solution in which sodium chloride and sodium carbonate were dissolved. A homogeneous solution was obtained. The solution was frozen by immersion of the tube in liquid nitrogen for a few seconds. The frozen solution was removed from the bath and let stand for a few minutes at room temperature. The organic phase (acetonitrile) was melted and collected on the solidified aqueous solution. The organic phase containing the derivatised phenols was removed and mixed with µL-level of 1,2-dibromoethane and injected into an aqueous solution of sodium chloride. The created cloudy solution was centrifuged and 1 μL of the sedimented phase was injected into the separation system. The effective parameters including the type and amount of base, amount of derivatisation agent, ionic strength of solutions, type and volume of solvents, and vortexing time were investigated. High extraction recoveries (80–92%) and enrichment factors (412–478), wide linear ranges, and satisfactory limits of detection (4.82–9.27 μg L−1) and quantification (14.25–30.86 μg L−1) were obtained.

Combination of homogeneous liquid–liquid extraction and vortex assisted dispersive liquid–liquid microextraction for the extraction and analysis of ochratoxin A in dried fruit samples: Central composite design optimization

This paper presents a new analytical procedure based on combination of homogeneous liquid–liquid extraction (HLLE) and vortex-assisted dispersive liquid–liquid microextraction (VA-DLLME) for the accurate and reliable determination of ochratoxin A (OTA) in dried fruit samples. To enable selective extraction of the OTA, six hydrophobic deep eutectic solvents (hDESs) were prepared and tested as extraction solvents. Optimization of DES volume, pH, NaCl amount, and mixing time affecting the efficiency of VA-DES-DLLME step was achieved by central composite design (CCD). Using optimized conditions, the working range was obtained in the range 0.4–350 ng mL−1 with an enrichment factor of 138. The limit of detection was 0.12 ng mL−1. To evaluate the accuracy of the method, the samples were analyzed with both the HLLE-VA-DES-DLLME procedure and reference method. The precision of the method was investigated by intraday/interday studies. The robustness of the method was also evaluated by making minor changes to the optimized conditions. The HLLE-VA-DES-DLLME procedure was successfully applied to dried fruit samples and quantitative recoveries were obtained (92.1–99.2%) confirming its usefulness for implementation in routine analysis of food samples.

Lab-in-syringe automated protein precipitation and salting-out homogenous liquid-liquid extraction coupled online to UHPLC-MS/MS for the determination of beta-blockers in serum

A sample preparation method involving tandem implementation of protein precipitation and salting-out homogenous liquid-liquid extraction was developed for the determination of beta-blockers in serum. The entire procedure was automated using a computer-controlled syringe pump following the Lab-In-Syringe approach. It is based on the denaturation of serum proteins with acetonitrile followed by salt-induced phase separation upon which the proteins accumulate as a compact layer at the interphase of the solutions. The extract is then separated and diluted in-syringe before being submitted to online coupled UHPLC-MS/MS. A 1 mL glass syringe containing a small stir bar for solution mixing at up to 3000 rpm, was used to deal with sample volumes as small as 100 μL. A sample throughput of 7 h−1 was achieved by performing the chromatographic run and sample preparation procedure in parallel. Linear working ranges were obtained for all analytes between 5 and 100 ng mL−1, with LOD values ranging from 0.4 to 1.5 ng mL−1. Accuracy values in the range of 88.2–106% and high precision of <11% RSD suggest applicability for routine analysis that can be further improved using deuterated standards.

Subzero-temperature homogeneous liquid-liquid extraction for the stereoselective determination of chiral triadimefon and its metabolite in water, fruit juice, vinegar, and fermented liquor by HPLC.

A novel method based on homogeneous liquid-liquid extraction with deep eutectic solvents (DES) under subzero-temperature conditions in combination with high performance liquid chromatography (HPLC) for the determination of chiral fungicide triadimefon (TF) and its metabolite triadimenol (TN) in water, fruit juice, vinegar, and fermented liquor was developed in this study. The method involved using deep eutectic solvents (DES) under subzero-temperature conditions in combination with high performance liquid chromatography (HPLC). This novel technique, known as subzero-temperature homogeneous liquid-liquid extraction (STHLLE), offers several advantages, including high efficiency, time-saving, low-cost, and eco-friendliness. The enantiomers of chiral TF and TN were simultaneously separated and quantified using HPLC coupled with a Daicel Chiralpak OD-RH column. Various experimental parameters such as DES composition and volume, freezing condition, salt concentration, and pH were optimized to enhance the recoveries of the target analytes. Under the optimized conditions, spiked recoveries of six enantiomers (i.e., S-TF, R-TF, SR-TN, RS-TN, SS-TN, and RR-TN) in the water, fruit juice, vinegar, and fermented liquor samples were 82.2-100.1% with relative standard deviations of 0.4-10.1%. The current method demonstrated a detection range of 0.03-0.06 mg L-1 in the target analytes. This established technique exhibits potential for efficient and precise extraction and quantification of the enantiomers of TF and TN in water phase samples.

Development of salt-induced homogenous liquid-liquid extraction based on ternary deep eutectic solvent coupled with dispersive liquid-liquid microextraction for the determination of heavy metals in honey

In this work, a homogenous liquid–liquid extraction method was combined with dispersive liquid–liquid microextraction and utilized for the extraction of Co, Zn, Ni, Cu, Pb, and Tl from honey samples before their determination by inductively coupled plasma-atomic emission spectrometry. For this purpose, firstly, diluted honey solution was transferred into a glass test tube and mixed with a few milliliters of a mixture of n-butanol and choline chloride: menthol: p-aminophenol deep eutectic solvent. A homogenous solution was obtained. After that an appropriate amount of sodium chloride was added into the solution and sonicated for 6 min. During this step, the homogenous solution was broken and the mixture of n-butanol and the deep eutectic solvent mixture was collected on top of the solution. The supernatant phase was removed and quickly injected into deionized water. After centrifugation, the collected phase at the bottom of the tube was injected into the determination system. Under the optimum situations, low limits of detection (0.24–0.74 ng g–1) and quantification (0.79–2.46 ng g–1), high extraction recoveries (80–92%), and good repeatability (relative standard deviations equal to or less than 3.6% and 3.9% for intra– and inter-day precisions, respectively) were acquired. Finally, the offered method was employed for determination of the studied heavy metals in various honey samples marketed in Tabriz city, Iran.

Automated centrifugation-less milk deproteinization and homogenous liquid-liquid extraction of sulfonamides for online liquid chromatography

A novel approach to the determination of sulfonamides in milk based on the Lab-In-Syringe technique is presented. The method involves automated salting-out liquid-liquid extraction of the analytes, allowing simultaneous sample deproteination without requiring centrifugation or manual sample handling. The procedural parameters, including salt type, solvent-to-sample ratio, and salt solution volume, were studied. The extracts obtained were diluted in situ and transferred to online coupled liquid chromatography for analyte separation carried out in parallel to the subsequent extraction. In this way, a sample throughput of approximately 6 h−1 was achieved. The detection limits ranged from 25 to 32 μg L−1 using a 500 μL milk sample and spectrophotometric detection. The applicability of the developed method to sample analysis was proven by recovery values ranging from 73.2% to 94.1% (86.3% on average) for milk samples of different fat content spiked at 3 μg mL−1 level. Straightforward automation of one of the most laborious preparation steps in food analysis, i.e., deproteination, was demonstrated.

Toward green and efficient recycling of Au(III), Pd(II) and Pt(IV) from acidic medium using UCST-type ionic liquid

The development of efficient ionic liquids (ILs) for disposable separation and recovery of various precious metals was of great importance, but still faced difficult challenges. A phase change temperature-controlled system composed of IL and HCl solution was developed for the extraction and separation of Au(III), Pd(II) and Pt(IV) from secondary resources. UCST (upper critical solution temperature)-type IL ([1,4,7-TMTA][Tf2N]) possessed outstanding selectivity of precious metals and the property of temperature-controlled phase transition. The ability of ILs to form solvated hydrogen bonds was confirmed by quantum-chemical calculation to be correlated with their corresponding UCST. Different experimental parameters were optimized to explore the extraction behavior of IL. It is noteworthy that homogeneous liquid-liquid extraction system (HLLE) constructed by UCST-type IL could significantly enhance the extraction kinetic of Au(III), Pd(II) and Pt(IV) by decreasing phase interface resistance. For Au(III), Pd(II) and Pt(IV), when the system temperatures were higher than 40 °C, 49 °C and 65 °C, the maximum values were 98.5%, 98.3% and 93.2% at the highest efficiency. In addition, the extraction mechanism of anion exchange was revealed by UV–vis, IR, NMR and LC-MS spectrometry. At last, Au(III), Pd(II) and Pt(IV) could be selectively separated from multi-metal solutions where impurity ions coexist by K2C2O4, NH3·H2O and CS(NH2)2/HCl, respectively. After 5 cycles, the extraction performance of [1,4,7-TMTA][Tf2N] maintained. In summary, this paper overcame the obstacle of slow kinetics of solvent extraction technology, and pointed out a way for polymetallic co-extraction and separation in HLLE system.

Surfactant-assisted salting-out homogenous liquid–liquid extraction based on deep eutectic solvents using central composite design; application in the extraction of natamycin from fruit juices before its determination by HPLC-UV

In this study, for the first time, surfactant-assisted deep eutectic solvent-based salting-out homogenous liquid-liquid extraction performed in a narrow-bore tube has been introduced as a new sample pretreatment approach and used for the isolation of natamycin from fruit juices. In this method, firstly, tween 80 (as a surfactant) and a water-miscible ternary deep eutectic solvent composed of choline chloride: acetic acid: butanol (as an extractant) were added to the sample solution and a homogenous state was formed. This solution was transferred into a narrow-bore tube and in the following, the homogenous solution was broken by addition of sodium chloride (as a phase separation agent). By this action, the analyte was extracted into the produced tiny droplets of extractant. This phase was quantified by high–performance liquid chromatography-ultraviolet detection. Experimental conditions of the developed extraction procedure were investigated and optimized by means of central composite design with variables including surfactant and extraction solvent volume, pH, and sodium chloride amount. Under optimum conditions, low limits of determination and quantification (0.78 and 2.60 ng mL−1, respectively), acceptable repeatability (relative standard deviations of 4.9 and 7.1% for intra- and inter day precisions at a concentration of 25 ng mL−1), and satisfactory extraction recovery (76%) were obtained using the proposed method. At the end, the suggested method was effectively utilized for the analysis of natamycin in different juice samples.

Application of calcium oxide as an efficient phase separation agent in temperature-induced counter-current homogenous liquid-liquid extraction of aflatoxins from dried fruit chips followed by high-performance liquid chromatography-tandem mass spectrometry determination.

A temperature-induced counter-current homogenous liquid-liquid extraction procedure performed in a burette has been proposed for the isolation of aflatoxins B1, B2, G1, and G2 from various fruit chip samples. In this method, a homogenous solution of deionized water and cyclohexylamine is added to the solid sample and the resulted mixture is vortexed. In the following, the liquid phase is taken and passed through the burette filled with a mixture of calcium oxide (as a phase separation agent) and sand (to avoid clumping the calcium oxide). By doing so, the temperature of the solution is increased by hydration of calcium oxide and consequently, the homogenous state is broken and the aflatoxins are migrated into the resulted tiny droplets of cyclohexylamine. This phase is collected on the top of the solution owing to its low density with respect to an aqueous solution. Numerous parameters which can affect the efficiency of the suggested approach were evaluated and under the best situations, great repeatability, low limits of determination and quantification, and high extraction recoveries were acquired. In the end, the suggested approach was employed for the quantification of the selected aflatoxins in various fruit chips samples marketed in Tabriz City, Iran.

Polycyclic Aromatic Hydrocarbons in Antarctic Ice Core: Prior Study by Homogeneous Liquid-Liquid Extraction and High-Performance Liquid Chromatography.

Organic contamination has been less investigated in Antarctic snow and ice than in other matrices due to analytical operational problems. In this study, the concentration of 14 Polycyclic Aromatic Hydrocarbons was determined in a shallow firn core by Homogeneous Liquid-Liquid Extraction and High-Performance Liquid Chromatography with a Fluorescence Detector. This investigation aimed to develop a simple analytical methodology for future application directly in fieldwork, taking advantage of the simplicity and small sample volumes. The analyte recoveries were 71-99% considering a 100 ng L-1 initial concentration of each compound, with a relative standard deviation of 1.1-9.9%. Analytical sensitivity/ detection limit/ quantification limits varied from 7.8/ 20.3/ 67.6 ng L-1 for fluoranthene to 0.6/ 1.5/ 5.1 ng L-1 for anthracene. These analytical parameters allow us to apply the method to real samples. We found visible differences at various firn core depths when considering the sum of total analytes under study. The highest total concentration was 741 ng L-1 and the lowest one 134.9 ng L-1. The methodology can be applied without mixing samples with adequate analytical parameters, and it can preserve the firn core temporal resolution, which is an advantage for application in fieldwork.

Countercurrent Salting-out Homogenous Liquid-Liquid Extraction and Dispersive Liquid-Liquid Microextraction Based on the Solidification of Floating Organic Drop Followed by High-Performance Liquid Chromatography for the Isolation and Preconcentration of Pesticides from Fruit Samples.

Pesticides are widely used to control pests and prevent diseases in crops, including cereals, vegetables, and fruits. Due to factors such as the persistence of pesticides, bioaccumulation, and potential toxicity, pesticide residue monitoring in foodstuffs is very important. In the current research, we proposed a novel approach using countercurrent salting-out homogenous liquid-liquid extraction combined with dispersive liquid-liquid microextraction based on the solidification of floating organic droplets (DLLME-SFO) for isolation and preconcentration of pesticides from aqueous samples for analysis by high-performance liquid chromatography-ultraviolet detection (HPLC-UV). In brief, sodium chloride was used as a separation reagent, in a small glass column, through which was passed a mixture of an aqueous solution of, for example, fruit juice and acetonitrile. In this process, the droplets rose through the column and a separated layer would be formed on the remained an aqueous phase. Following that, acetonitrile as the organic phase was mixed with 50.0 µL of 1-undecanol (extraction solvent). To further enrich the analytes, the mixture was injected into 5 mL of a 4% w/v sodium chloride solution and placed in a tube for the DLLME-SFO. Under optimal conditions, a dynamic linear range of 0.5-500 μg/L, extraction recovery of 65-85%, enrichment factors of 108-142, and limit of detection of 0.2-0.4 μg/L were obtained for the organophosphorus pesticides analysed. In addition, the repeatability and reproducibility from five replicate measurements of the pesticides (100 μg/L) were within the ranges of 3.5-5.1% and 4.5-6.3%, respectively . In this research, a new extraction method based on countercurrent salting out homogeneous liquid-liquid extraction combined with DLLME-SFO has been applied for the determination of pesticide residues in fruits, juice and environmental samples before using HPLC-UV analysis. The combined method not only leads to high enrichment factors, but can also be used in complex matrices (such as fruits, juices and high-salt solutions) without pre-treatment or dilution. Compared with other sample preparation methods, this analysis procedure has many advantages, including simplicity, ease of operation, high pre-enrichment factor, low detection limit and relatively short analysis time. Combination of CCSHLLE and DLLME-SFO was applied for the analysis of organophosphorous pesticide residues in fruit, fruit juices and environmental samples. The DLLME-SFO method avoided using high density and toxic extraction solvents. LODs are achievable at ng L-1 using CCSLLE-DLLME-SFO-HPLC-UV.

Development of sodium hydroxide-induced homogenous liquid-liquid extraction-effervescent assisted dispersive liquid-liquid microextraction based on deep eutectic solvents; Application in the extraction of phytosterols from cow cream samples

In this study, sodium hydroxide-induced homogenous liquid-liquid extraction was combined with effervescent assisted-dispersive liquid-liquid microextraction and used for the extraction of phytosterols (lupeol, β-sitosterol, stigmasterol, campesterol, and brassicasterol) from cream samples. Two types of deep eutectic solvents (water-miscible and water-immiscible solvents) were prepared and used in the extraction procedure. In this approach, firstly, the sample was dissolved in a mixture of n-hexane and tetrabutylammonium bromide: ethylene glycol deep eutectic solvent (as extraction/disperser solvent) and a homogenous solution was obtained. After that, a few microliters of sodium hydroxide solution (as fatty acid saponification and phase separation agent) was quickly injected into the mixture. By doing so, a three-phase system was formed. Then, the supernatant phase (tetrabutylammonium bromide: ethylene glycol deep eutectic solvent) was removed and mixed with tetrabutylammonium bromide: dichloroacetic acid: octanoic acid deep eutectic solvent. The obtained solution was applied in the microextraction step. To obtain effective, reliable, robust, accurate, and precise analytical results, the effective parameters for the presented method were investigated and optimized in detail. Detection limits, extraction recoveries, and enrichment factors were in the ranges of 0.06–0.26 μg kg–1, 86–93 %, and 215–232, respectively. Intra- and inter-day repeatabilities were investigated at a concentration of 1.5 μg kg–1 (each analyte) and they were in the ranges of 5.3−7.5 and 7.2–8.8 %, respectively. Finally, the presented method was easily used in determination of the phytosterols in cow milk cream samples.

Dispersive liquid-liquid microextraction method combined with sugaring-out homogeneous liquid-liquid extraction for the determination of some pesticides in molasses samples.

In this study, a sensitive analytical method was developed to determine some pesticides (cyprodinil, trifloxystrobin, prometryn, propachlor, fenitrothion, chlorpyrifos, profenofos, and phosalone) in molasses samples. Pesticides were extracted from samples by dispersive liquid-liquid microextraction method combined with sugaring-out homogeneous liquid-liquid extraction and determined by gas chromatography-mass spectrometry analysis. In this method, pesticides in molasses samples were first extracted using a water-miscible solvent (acetonitrile) in the sugaring-out homogeneous liquid-liquid extraction stage. The sugar in the ratio of 84-88% naturally contained in the molasses sample enabled phase separation in the acetonitrile-water homogeneous mixture. Then acetonitrile phase containing pesticides was used as dispersing solvent in the second step of the process. Under the specified optimum conditions, the limit of detection was calculated between 0.8-6.1ng/g and the limit of quantification was in the range of 2.5-20ng/g. The relative standard deviation values of molasses samples containing 150ng/g of each analyte were found to be lower than 4.9% intra-day and 5.6% for inter-day. This validated method has been successfully applied to different types of molasses.

Homogeneous liquid-liquid extraction as an alternative sample preparation technique for biomedical analysis.

Liquid-liquid extraction is a widely used technique of sample preparation in biomedical analysis. In spite of the high pre-concentration capacities of liquid-liquid extraction, it suffers from a number of limitations including time and effort consumption, large organic solvent utilization, and poor performance in highly polar analytes. Homogeneous liquid-liquid extraction is an alternative sample preparation technique that overcomes some drawbacks of conventional liquid-liquid extraction, and allows employing greener organic solvents in sample treatment. In homogeneous liquid-liquid extraction, a homogeneous phase is formed between the aqueous sample and the water-miscible extractant, followed by chemically or physically induced phase separation. To form the homogeneous phase, aqueous samples are mixed with water-miscible organic solvents, water-immiscible solvents/cosolvents, surfactants, or smart polymers. Then, phase separation is induced chemically (adding salt, sugar, or buffer) or physically (changing temperature or pH). This mode is rapid, sustainable, and cost-effective in comparison with other sample preparation techniques. Moreover, homogeneous liquid-liquid extraction is more suitable for the extraction of delicate macromolecules such as enzymes, hormones, and proteins and it is more compatible with liquid chromatography with tandem mass spectrometry, which is a vital technique in metabolomics and proteomics. In this review, the principle, types, applications, automation, and technical aspects of homogeneous liquid-liquid extraction are discussed.

High-throughput subzero-temperature assisted homogenous liquid-liquid extraction for the fast sample preparation of multiple phenolic compounds in propolis

In the present study, a high-throughput homogenous liquid-liquid extraction method was developed for fast sample preparation of multiple phenolic compounds in propolis. This method was proposed based on cooling samples array in subzero temperature to induce phase separation of ACN-H2O extractant. Due to the high-throughput ability, optimization of extraction parameters was rapidly achieved by using a 5 × 4 × 3 samples array. In addition, multiple arrays were investigated for evaluating the analytical performance of the high-throughput method, which indicated that limits of detection and quantification were ranged from 0.04 to 0.35 µg/mL and 0.12 to 1.05 µg/mL, respectively. Recoveries and precisions in inter-day high-throughput studies were in the range of 90.55–105.50% and 2.58–4.30%, respectively. Comparing with the conventional liquid extraction method, this ecofriendly high-throughput method presented remarkable advantages in reducing sample and chemical consumption, as well as saving labor and time cost. The proposed method might provide a valuable strategy for the design of high-throughput extraction procedures.

Development of Homogeneous Liquid-Liquid Extraction in Combination with Dispersive Liquid-Liquid Microextraction Based on Deep Eutectic Solvents for the Extraction and Assessment of Phytosterols in Animal Cream Samples using Gas Chromatography Equipped with Flame Ionization Detector

Development of Homogeneous Liquid-Liquid Extraction in Combination with Dispersive Liquid-Liquid Microextraction Based on Deep Eutectic Solvents for the Extraction and Assessment of Phytosterols in Animal Cream Samples using Gas Chromatography Equipped with Flame Ionization Detector

Development of a pH-dependent homogeneous liquid-liquid extraction by cold-induced phase separation in acetonitrile/water mixtures for determination of quinolone residues in animal-derived foods

A simple extraction procedure coupled with liquid chromatography-Q Orbitrap high resolution mass spectrometry (LC-Q Orbitrap HRMS) for the determination of 19 quinolones in animal-derived foods (pork, fish, egg and milk) has been developed. Sample preparation is based on homogeneous liquid-liquid extraction at pH > 9 using water-miscible acetonitrile with cold-induced phase separation. The procedure allowed one-step enrichment and cleanup of all the 19 quinolones with different logP properties to lower aqueous phase, which eliminated the process of preconcentration and re-dissolution for sample solution. Furthermore, an adsorption phenomenon was observed between conventional borosilicate glass injection vials and most of quinolones. In detection analysis, a scheduled variable full scan strategy was performed to improve detection performance in Q Orbitrap HRMS. Under optimal conditions, a superior limit of quantitation (0.028–0.192 μg/kg) in animal-derived foods was achieved using this proposed method. Lastly, this method was validated and applied successfully in real samples.

Micro Salting-Out Assisted Matrix Solid-Phase Dispersion: A Simple and Fast Sample Preparation Method for the Analysis of Bisphenol Contaminants in Bee Pollen.

In the present work, a novel sample preparation method, micro salting-out assisted matrix solid-phase dispersion (μ-SOA-MSPD), was developed for the determination of bisphenol A (BPA) and bisphenol B (BPB) contaminants in bee pollen. The proposed method was designed to combine two classical sample preparation methodologies, matrix solid-phase dispersion (MSPD) and homogenous liquid-liquid extraction (HLLE), to simplify and speed-up the preparation process. Parameters of μ-SOA-MSPD were systematically investigated, and results indicated the significant effect of salt and ACN-H2O extractant on the signal response of analytes. In addition, excellent clean-up ability in removing matrix components was observed when primary secondary amine (PSA) sorbent was introduced into the blending operation. The developed method was fully validated, and the limits of detection for BPA and BPB were 20 μg/kg and 30 μg/kg, respectively. Average recoveries and precisions were ranged from 83.03% to 94.64% and 1.76% to 5.45%, respectively. This is the first report on the analysis of bisphenol contaminants in bee pollen sample, and also on the combination of MSPD and HLLE. The present method might provide a new strategy for simple and fast sample preparation of solid and semi-solid samples.

Homogenous Liquid–Liquid Extraction of Au(III) from Acidic Medium by Ionic Liquid Thermomorphic Systems

Two ionic liquid (IL) thermomorphic systems were designed. The thermoregulated property exhibited by the IL systems was utilized for the recovery of Au(III) from acidic medium. The cloud point order of the two ILs was proposed and evidenced via a combination of experimental measurements and quantum chemical calculations. The impacts of salt ions and acid on the thermomorphic phase behavior of the IL–H₂O binary mixture system were investigated. After comprehensive comparison, a systematic study of Au(III) extraction by the [Suc][Tf₂N]₂ (succinyl bis(trifluoromethylsulfonyl)imide) system was carried out because of its outstanding hydrophobicity and extraction ability. Then, a comparison between traditional liquid–liquid extraction (TLLE) and homogeneous liquid–liquid extraction (HLLE) was made during the process of optimization of various extraction parameters. In addition, the anion-exchange mechanism in the extraction process was revealed. The thermoregulated [Suc][Tf₂N]₂ system presented an excellent selectivity for Au(III) in a solution of coexisting multimetallic ions. Finally, Au(III) was almost completely stripped from the loaded IL phase by oxalic acid. The extraction efficiency of Au(III) using regenerated IL still maintains a surprising stability after five turns of cycling experiments. Hence, the dicationic IL [Suc][Tf₂N]₂ was regarded as a potential extractant for the recovery of gold.