Top Phase Research Articles

The temperature influence on the phase behavior of ionic liquid based aqueous two-phase systems and its extraction efficiency of 2-chlorophenol

With the increasing research on the aqueous two-phase systems (ATPS), the ATPS containing ionic liquid (IL) and salt have been widely used in the extraction and purification process. In this work, the partitioning of 2-chlorophenol in novel ATPS composed of n-butylpyridinium trifluoromethanesulfonate and salts (ammonium sulfate, sodium dihydrogen phosphate) is evaluated. Firstly, the cloud point titration method was used to determine the binodal curves data experimentally at four temperatures and atmospheric pressure. And Merchuk equation was used to fit the binodal curves. Then, the gravimetric method was used to initially determine the tie-lines data and the concentration of all the ions in the top and bottom phases were determined by ion chromatography method to study the ion exchange in the ATPS. The reliability of tie-lines was evaluated by Othmer-Tobias and Bancroft equations. Finally, the influence of types of salts and temperature on the phase diagrams were studied carefully. Besides, in order to analyze the application of ATPS in the extraction, the partition coefficient of 2-chlorophenol was calculated at the same total composition while at different temperature. The ATPS formed by n-butylpyridinium trifluoromethanesulfonate, ammonium sulfate, and water at 298.15 K was found to have the maximum amount of partition coefficient and extraction efficiency.

Partition efficiency of cytochrome c with alcohol/salt aqueous biphasic flotation system

Aqueous biphasic flotation (ABF) integrates aqueous biphasic system (ABS) and solvent sublation for recovery of target biomolecules. The feasibility of the alcohol/salt ABF for exclusive partition of cytochrome c to one specific phase of the system was investigated. Aliphatic alcohols of different carbon chain length (ethanol, 1-propanol and 2-propanol) and salts (sulfate, phosphate and citrate) were used for the phase formation. The effects of phase composition, concentration of sample loading, pH, flotation time and flow rate of the system on the partition efficiency of cytochrome c were determined. Cytochrome c was exclusively partitioned to the alcohol-rich top phase of the ABF of 18% (w/w) ethanol and 26% (w/w) ammonium sulfate with pH 6 and 20% (w/w) of sample loading. Highest partition coefficient (K) of 6.85±0.21 and yield (YT) of 99.40%±0.02 were obtained with optimum flotation rate of 10mL/min and flow rate of 10min.

Separation of erythromycin using aqueous two-phase system based on acetonitrile and carbohydrates

In this work, the ability of aqueous two-phase system (ATPS) based on carbohydrates (sorbitol, maltose monohydrate, and fructose) and acetonitrile for separation of erythromycin was investigated. For this purpose, binodal curves and tie-lines for three ATPSs were determined. The LLE data was also successfully correlated with the Othmer-Tobias and the Bancroft equations. The effective excluded volume (EEV) model was used to estimate the soluting-out ability of carbohydrates. Moreover, the partitioning of erythromycin in the ATPS was studied. Furthermore, the effect of carbohydrate and acetonitrile concentrations as well as temperature on the partitioning behavior of erythromycin were examined. In order to estimate the effect of temperature on the partitioning of erythromycin, molar Gibbs energy (ΔGEA), molar entropy (ΔSEA), and molar enthalpy (ΔHEA) were calculated. In all ATPSs the top phase is acetonitrile-rich while the bottom phase is carbohydrate-rich and erythromycin tends to migrate to the top phase. The results show that sorbitol has a higher soluting-out ability than maltose monohydrate and fructose. In addition, it can be concluded that the partitioning process of erythromycin is exothermic and the partition coefficient was decreased with increasing of erythromycin content.

Partitioning of salicylic and acetylsalicylic acids by aqueous two-phase systems: Mechanism aspects and optimization study

Emerging contaminants such as drugs and pharmaceuticals have attracted attention in recent years due to their adverse effects in humans and the environment. They are difficult to monitor, since they are present at very low concentrations in environmental matrices. Acetylsalicylic acid (ASA) and salicylic acid (SA) are the most highly consumed drugs worldwide. In this investigation, an extensive study of acetylsalicylic acid and salicylic acid partitioning was carried out in aqueous two-phase systems (ATPSs) formed by a polymer, salt, and water. In the univariate analysis, the length of the tie line and the nature of the polymer and electrolyte that form the ATPS were found to have strong effects on the partition coefficients (K) of ASA and SA, while pH had a significant effect on the partition coefficient of ASA only. In all conditions, the analytes partitioned preferentially to the top phase (K >>1), indicating a preferential interaction of the analytes with the components of this phase. A multivariate study of the optimal SA partition conditions was carried out through a central composite design, showing that the optimal ATPS for SA partitioning is composed of [PEO1500] = 29.06 %wt and [Li2SO4] = 11.94 %wt at pH 6.1. Under these optimal conditions, the expected value for K is ±940. Eight replicates of this system reported a real value of K = 949 (±47). Thus, the ATPS was demonstrated to be an efficient system for the extraction of SA and ASA, with high K values.

Microwave-assisted three-liquid-phase salting-out extraction of docosahexaenoic acid (DHA)-rich oil from cultivation broths of Schizochytrium limacinium SR21

The extraction and separation of docosahexaenoic acid (DHA)-rich oils, proteins, and polysaccharides from microalgae is a challenge for industrial commercialization of DHA, such as drying and dewatering, cell wall disruption, laborious conventional extraction procedures and exploitation of large volumes of solvents. To address these concerns, a novel microwave-assisted three-liquid-phase salting-out extraction (MA-TLPSOE) was used to separate DHA-rich oils, proteins, and polysaccharides from wet cultivation broths of Schizochytrium limacinum SR21. The optimized MA-TLPSOE system was composed of 30% (w/w) n-hexane/13% (w/w) ethanol/9% (w/w) sodium carbonate and treated at high microwave power (650W) for 30s. Under optimized conditions, 100±0.59% oil and 100±0.64% DHA were partitioned in the top n-hexane phase while 93.75±0.25% of polysaccharides and 92.96±0.43% of proteins were distributed in the solid-phase interface. The effects of microwave power and duration, sodium carbonate, n-hexane, ethanol concentration and extraction time were studied. When the optimized system was enlarged from 20g to 60g, the yields of all effective components were almost the same. Thus, the MA-TLPSOE system is a promising and attractive technology, which could be used for the separation and extraction of various effective ingredients from complex natural products in a single step with significant recovery yield.

Partitioning of tylosin in recyclable aqueous two-phase systems based on two pH-responsive polymers

Abstract Aqueous two-phase systems (ATPS) are a promising biotechnology in bioseparation. However, recycling of the phase-forming polymer is a key issue. In this research, new recyclable ATPS composed of two pH-responsive polymers (PADB4.01 and PMDBH3.27) were prepared. The ATPS could be recycled by adjusting the pH of the solution, with recovery of 93.8%. The ATPS were evaluated for the first time in the partitioning of tylosin. The effects of the main parameters, such as the polymer concentration, pH, temperature, salt species and concentrations, on the partition of crude tylosin and tylosin from fermentation broth were studied. In the 2% PMDBH3.27/3% PADB4.01 ATPS, the partition coefficient (K) and extraction recovery (ERtop) of crude tylosin could reach 5.12 and 93.9%, respectively, in the presence of 90 mM KCl at pH 5.83 and 25 °C. In the 2.5% PMDBH3.27/3% PADB4.01 ATPS, the K and ERtop of tylosin from fermentation broth reached 3.58 and 87.3%, respectively, in the presence of 20 mM KBr at pH 5.69 and 25 °C. Through partition mechanism analysis by Fourier transform infrared spectroscopy (FT-IR) and interphase potential measurements, the appearance of a new absorption peak and interphase potential difference, respectively, may contribute to the partitioning of tylosin in the PADB4.01-enriched top phase.

Enantioselective liquid-liquid extraction of valine enantiomers in the aqueous two-phase system formed by the cholinium amino acid ionic liquid copper complexes and salt

It was widely reported that the heterocyclic ionic liquids (ILs) had relatively high biotoxicity and the cholinium amino acid ionic liquids (ChAAILs) were much environmentally friendly. Therefore, the ChAAILs/salt aqueous two-phase systems (ATPSs) were developed for the chiral resolution of valine enantiomers in this study. The copper complexes were prepared by ChAAILs and Cu(Ac)2, which can be used as both the phase-forming components and the chiral selectors. A series of factors affecting the enantioseparation result were investigated, including type and concentration of ChAAILs, molar ratio of ChAAIL and Cu(Ac)2, type and concentration of salt, concentration of valine, and operation temperature. The valine enantiomers were preferentially recognized in the ChAAIL-rich phase (top phase) and the maximum e.e. value of 55.6% was obtained in the top phase. This ATPS used for the enantioseparation of valine enantiomers has the advantages of environmental friendliness, high enantioseparation efficiency and simple operation by one step extraction.

Sedimentation rate-based screening of oleaginous microalgae for utilization as a direct combustion fuel

The co-combustion of microalgae biomass with coal has the potential to significantly reduce CO2 emissions by eliminating expensive and carbon-emitting downstream processes. In this study, the utilization of microalgal biomass as a direct combustion fuel in co-firing industries and the screening of potential oleaginous strains of high calorific value was investigated. High-lipid accumulating mutants were selected from mutant mixtures based on cell density using differential sedimentation rates. Of the mutant strains obtained in the top phase of the separation medium, 72% showed a higher lipid content than the wild-type strain. One mutant strain exhibited a 57.3% enhanced lipid content and a 9.3% lower heating value (LHV), both indicators of direct combustion fuel performance, compared to the wild-type strain. Our findings indicate that sedimentation rate-based strain selection allows for the easy and rapid screening of high-lipid content algal strains for the use of microalgae as direct combustion fuels.

Separation of adjacent rare earth elements enhanced by “external push-pull” extraction system: An example for the separation of Pr and Nd

Separation of adjacent rare-earth elements, such as Pr and Nd, is extremely difficult due to the similarity in their physicochemical properties. Enhanced separation of adjacent rare-earth elements based on the “push-pull effect” by addition of water-soluble complexing agents was an effective strategy in traditional organic-aqueous two-phase extraction. However, environmental pollution is serious due to the residual of complexing agent in the extraction raffinates. In present work, a novel “external push-pull” extraction system, composed of three coexisting liquid phases, P507 organic phase, ionic liquid (tributyl-methyl ammonium nitrate, N4441NO3)-rich phase and NaNO3 aqueous solutions, is suggested to improve the separation between Pr and Nd. It is revealed that Nd and Pr can be enriched respectively into the P507 organic top phase and N4441NO3-rich ionic liquid middle phase in the external push-pull extraction system, owing to a so-called “external push-pull effect” from a reversed extraction selectivity of P507 organic phase and N4441NO3 ionic liquid-rich phase towards Nd and Pr, respectively. Compared to traditional organic-water two-phase systems, the separation factor of Pr to Nd in the suggested external push-pull extraction system could increase obviously to 3.5 or even more. Various effects from the aqueous pH, NaNO3 concentration, the initial concentration ratios of Pr to Nd in feed aqueous solutions, and the addition amount of N4441NO3, the volume of P507 organic phase on the separation between Pr and Nd are discussed. In addition, reversal extraction of rare earth ions in the ionic liquid-rich phase is found to be closely related to the complexation behavior of rare earth ions with NO3− ions by using molecular dynamic simulations. Based on this work, a possibility for extraction and separation of 14 rare-earth element ions from their coexisting aqueous solutions using the suggested external push-pull extraction system is also explored. The present work highlights a novel green strategy for improving the separation of adjacent rare-earth elements.

Extraction induced by microemulsion breaking as a novel tool for the simultaneous determination of Cd, Mn, Pb and Sb in gasoline samples by ICP-MS and discrete sample introduction

This study reports a simple and efficient method for the simultaneous determination of Cd, Mn, Pb, and Sb at trace levels in gasoline samples by discrete sample introduction in inductively coupled plasma mass spectrometry (ICP-MS), employing the extraction induced by microemulsion breaking as a sample preparation method. In this work, a microemulsion was formed by mixing 0.7 mL of the gasoline sample with 0.28 mL of ethanol and 0.02 mL of 7 mol L−1 HNO3 solution. Afterwards, 0.1 mL of ultrapure water was added to induce microemulsion breaking. This lead to the formation of two different phases: (i) a top organic phase and (ii) a bottom aqueous phase that contained acid, ethanol and the extracted analytes. After that, 20 μL of the bottom phase (extract) was collected, and the analyte concentrations were determined by discrete sample introduction in ICP-MS. Calibration curves with 20 μg L−1 of Rh as an internal standard were set up to each analyte in the range from 1 up to 10 μg L−1, wherein the standard solutions were prepared in the matrix-matched extract (70:25:5, ethanol: deionized water: 7 mol L−1 HNO3 solution). The optimization of the EIMB conditions was carried out by analyzing the effects of the parameters that could affect the extraction efficiency, such as the relation between the nature of the alcohol and the proportion of the volumes of the microemulsion constituents (sample, HNO3 and alcohol), acid concentration, and the water volume used for the microemulsion breaking. The following limits of detection relative to the amount of sample were obtained: 0.03 (Cd), 0.49 (Mn), 0.07 (Pb) and 0.02 (Sb), all of them in μg L−1. The accuracy of the method was evaluated by the analysis of spiked samples, because no certified gasoline reference material is available. The average recoveries achieved for every analyte ranged from 96% to 114%. The developed methodology was successfully applied to the determination of these metals in five commercial gasoline samples.

Acetonitrile and Na+ or K+ Salts as Constituents of the Aqueous Two-Phase System: Equilibrium Data and Capsaicin Purification

The pharmaceutical and food industries are interested in capsaicin because of its therapeutic and functional potential; however, it is necessary to develop an efficient protocol for extraction and purification of capsaicin from natural sources. Thus, this paper aims to study the partitioning and purification of capsaicin from capsicum peppers using aqueous two-phase systems (ATPSs) based on Na+ or K+ salts. Initially, phase diagrams were determined, and the ease of phase formation of acetonitrile + different salts ATPS followed the reverse of Gibbs free energy of hydrations. Capsaicin migrated preferentially to the top phase (acetonitrile-rich phase) by an endothermic and spontaneous process governed by entropic forces. The best condition of separation (KCPS = 43.95 ± 1.52; EECPS = 89.06 ± 1.17%; PFCPS = 2.65 ± 0.01 fold) was found using acetonitrile (20 wt %) + K2CO3 (15 wt %) + water (65 wt %) at 318 K and 0.1 MPa.

Surfactant as selective modulator in the partitioning of dyes in aqueous two-phase systems: A strategy for separation

In this work, aqueous two-phase systems (ATPSs) were employed to separate two model dyes, remazol golden yellow (RY) and methylene blue (MB), using the cetyltrimethylammonium bromide (CTAB) surfactant as a selective modulator in the partitioning. Experiments involving individual and simultaneous partitioning of the dyes were performed in the absence and presence of CTAB in ATPSs formed by a polymer (polyethylene glycol (PEG), polypropylene glycol (PPG), or poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) copolymer (L35)), a salt ((NH4)2SO4, MgSO4, Na2SO4, or Li2SO4), and water. In experiments of individual partitioning, RY and MB were transferred to the top phase in ATPSs formed using PEG in the absence of CTAB. However, in the presence of certain surfactant concentrations, the MB dye remained in the top phase, while the RY dye was transferred to the bottom phase. The same result was obtained in experiments of simultaneous partitioning. This was attributed to a specific interaction between CTAB and RY, which promoted the formation of RY-CTAB aggregates that were stabilized in the bottom phase. The amount of RY transferred to the bottom phase in the presence of CTAB was highly dependent on the polymer molar mass and the natures of the salt and the polymer. Interestingly, the surfactant did not promote the transfer of RY to the bottom phase in ATPSs formed by PPG or L35, due to competition between the polymer and the RY dye for the CTAB monomers. The best separation factor between the dyes was of 271.2 in the ATPS formed by PEG with molar mass of 1500 g mol−1, MgSO4, and water, hence demonstrating the potential of ATPSs for separation among dyes.

Syncytiotrophoblast basal membrane-derived exosomes increase NO generation in human umbilical vein endothelial cells

Rhenium and molybdenum are valuable metals present in the earth's crust in very low concentration and are increasingly used in industry thanks to their multiple properties, but due to the harmful aspects of the production process, there is a need to develop systems of concentration or purification of salts of these elements. For this work a PEG/Na2MoO4 aqueous two phase system (ATPS) was used for the partition of ReO4- anion. By using a central composite design, the effects of PEG concentration, sodium molybdate concentration, temperature, pH and their possible interaction on the partition coefficient were studied, also to estimate the optimal configuration of the factors that influence the process. At the same time, experimental density, sound velocity and isentropic compressibility were also obtained for top and bottom phases. The results showed that the optimal conditions for the partition of ReO4− anion using the ATPS formed by PEG and Na2MoO4 were 14.7 wt% PEG 4000, 16.3 wt% Na2MoO4, 35 °C and pH 6. For these conditions, the partition coefficient (K) obtained was up to 17.8 ± 0.78. The order of factors with high significance on the partition coefficient was: Na2MoO4 concentration > PEG concentration > temperature > pH > interaction between Na2MoO4 and PEG concentrations; the effect of these parameters mainly is related with the speciation, salting-out effect and hydrophobicity. The influence of these factors on the density, and sound velocity of the top phase was minimal, unlike its influence on the properties of the bottom phase, not isentropic compressibility and effect of PEG and Na2MoO4 concentrations on sound velocity. The evaluation of the partitioning behavior was made by experimental design, applying statistical regression analysis and analysis of variance (ANOVA). The statistical models for partition coefficient and for phase densities (and the other properties) as function of parameters with significant effects were obtained, and also a good correlation between experimental and correlated data was observed (R-Squared = 0.9379, ReO4− partition coefficient; 0.9882, bottom phase; and 0.9836 upper phase). This work is oriented to the possible application in stripping of a top phase provided for a co-extraction of rhenium and molybdenum by ATPS in acidic media or in solutions with high contend of Mo such as those provided by pressure oxidative leaching of molybdenite in basic media.

HR analytics a roadmap for decision making: case study

<p>In the socio-economic world, the human resources are in the most top phase of the enterprise evolution. This evolution began when the arithmetic, statistics are applicable over a vast of opportunities and used to identify problems and support decision. However, analytics has been emerged to provide predictions and understand the people performance based on available data.</p>In light of this vast amount of information, human resources services need to deploy a predictive management model and operating system of analytics that can be an efficient and an instead solution that can respond to the gaps of the traditional existing ones and facilitate the decision making. In this paper, we present a literature review of this HR analytics concept and a case study concerning the impact of interventions using an analytics solution.<p> </p>

Selective purification of protease from ginger and sodom apple by ultrasound assisted liquid-liquid microextraction using natural deep eutectic solvent

Ultrasonic assisted liquid-liquid microextraction (UA-LLME) of cysteine proteases from ginger and sodom apple were accomplished with natural deep eutectic solvents (NADES). Five imidazole-based NADES with carbohydrates were synthesised and their thermophysical properties were investigated. Selective partitioning of NADES assisted UA-LLME yielded more protease in NADES enriched top phase. Choice of phase forming compounds and their influence in the concentration of protease was evaluated by calculating the partition coefficient. The linearity of detection, LOD and LOQ for protease were found to be 10–50 μg/ml, 15 and 60 μg/ml respectively. Influential variables towards the extraction were optimised with response surface methodology and it was noted that maximum yield was achieved with 25% (v/v) of NADES, 15% (w/v) of source concentration and ultrasound temperature and time as 35 °C and 10 min respectively. The concentrated extract was purified by gel filtration chromatography was performed followed by affinity chromatography and purity fold with %yield of the enzyme was observed.

Localized surface plasmon resonance tunability of VO2/Au/VO2 composite nanotriangle sandwich array

A vanadium dioxide (VO2) and Gold nanotriangle composite sandwich structure (VO2/Au/VO2) was fabricated via nanosphere lithography technique. It exhibits reversible localized surface plasmon resonance tunability through external thermal stimuli VO2 phase transition by tuning the near-field permittivity of Au nanotriangle. Compared optical response to the Au/VO2 (bottom Au top VO2) and VO2/Au (bottomVO2 top Au) composite nanotriangle arrays, VO2/Au/VO2 structure shows a largest wavelength shift of 42 nm and a largest transmittance modulation of 13.2% between the hot-metallic and cold-insulating states. And the wavelength shift of Au/VO2 nanotriangle array is larger than that of VO2/Au array for the higher electric intensity on top surface of Au nanotriangle. The results suggest that this sandwich architecture is one path for designing a plasmonic structure with tunable resonance responses that can be tailored by varying the top and bottom phase materials properties of the hybrid structures.

Relationship between flight ratio and relative vertical acceleration force of the upper limbs and the recovery leg during the top speed phase in sprint running

Relationship between flight ratio and relative vertical acceleration force of the upper limbs and the recovery leg during the top speed phase in sprint running

Characterization of Ionic Liquid Aqueous Two-Phase Systems: Phase Separation Behaviors and the Hydrophobicity Index between the Two Phases.

1-Allyl-3-methylimidazolium chloride [Amim][Cl] and 1-butyl-3-methylimidazolium chloride [Bmim][Cl] are water-soluble ionic liquids (ILs) that can from an aqueous two-phase system (ATPS) when mixed with specific salts. Herein, we prepared [Amim][Cl]- and [Bmim][Cl]-ATPSs by adding the salts (K2CO3, K2HPO4). To investigate the phase separation behavior of the IL-ATPSs, binodal curves were drawn at different temperatures and the length and slope of the tie lines were analyzed. The [Bmim][Cl]/K2HPO4 system underwent two-phase separation at lower temperature conditions, suggesting that the phase separation might depend on the salting-out effect in the bottom phase. Using the IL-ATPS, the distribution coefficients, Kaa, of amino acids were determined and used to characterize the hydrophobicity index (HF) between the top and bottom phases, which is a good indicator to understand the molecular partitioning behaviors in conventional ATPSs. The HF values of the IL-ATPSs were in the range 0.13-0.41 mol/kJ; these values were almost the same as the HF values reported for an ATPS composed of poly(ethylene glycol) and salt.

Microwave-assisted aqueous two-phase extraction of diverse polysaccharides from Lentinus edodes: Process optimization, structure characterization and antioxidant activity

Microwave-assisted aqueous two-phase extraction (MAATPE) was applied to simultaneous extraction of diverse polysaccharides from Lentinus edodes with aqueous two-phase extraction system (ATPS) of ethanol/ammonium sulfate as the biphasic extractant. Key factors in MAATPE process were optimized by response surface methodology, and the optimum conditions were concluded as follows: the ATPS composition of ethanol concentration 26.0% (w/w) and (NH4)2SO4 concentration 19.58% (w/w), extraction temperature 78.7 °C, extraction time 19.55 min and solid-to-solvent ratio 1:50. The extraction yields of the polysaccharides from the top phase (PTP) and the bottom phase (PBP) were 2.12 ± 0.21% and 11.16 ± 0.28%, respectively. By means of FT-IR, HPGPC and HPLC analysis, PTP and PBP were different from each other in chemical structure, their average molecular weight (MW) were respectively 119,533 Da and 3906 Da. Also, the mechanism of MAATPE process was explored by composition analysis and scanning electron microscopy. Both polysaccharides exhibited stronger antioxidant activities, EC50 values of scavenging DPPH, hydroxyl and superoxide radicals for PBP achieved 580 ± 3, 83.1 ± 3.6 and 91.1 ± 0.5 μg/mL as against 560 ± 4, 76.3 ± 2.2 and 89.3 ± 2.4 μg/mL of PTP, respectively. Compared with conventional methods using a mono-phase solvent, MAATPE can not only greatly improve extraction efficiency, but also selectively extract diverse polysaccharides.

Optimized Microstructure and Properties of Cr3C2-NiCr Cermet Coating by HVOF/Laser Hybrid Processing

Thermal spraying has been widely used to obtain functional surface coatings against wear or corrosion in various industrial fields. However, pores and low bonding strength are the two inevitable drawbacks for thermal-sprayed coatings. In this study, a hybrid process combining thermal spraying with laser beam irradiation was employed to solve the drawbacks. A Cr3C2-NiCr cermet coating was processed successively by high-velocity oxygen-fuel spraying and laser remelting. A fully dense remelt layer without any cracks was successfully obtained. The remelt layer was composed of fused steel base metallurgically bonded with cermet coating, showing a transverse gradient microstructure in aspects of chemical composition and grain shapes. On the top surface, chemical composition and phases from the original coating were preserved, contributing to the enhanced properties of electrochemical corrosion and wear resistance. The improvement was discussed in terms of structure densifying and homogenization. The enhanced properties by the HVOF/laser hybrid process indicate promising application in industrial fields.