Eutectic Sample Research Articles

Anisaldehyde-based deep eutectic solvent dispersive liquid–liquid microextraction (DES-DLLME) followed by UPLC–MS/MS for simultaneous determination of selected parabens and bisphenols in food products: Method development and assessment of the ecological implications

A rapid and environmentally friendly method based on dispersive liquid–liquid microextraction (DLLME) technique, coupled with UPLC–MS/MS analysis was employed for simultaneous determination of selected bisphenols and parabens residues in food products. In this research, anisaldehyde and decanoic acid with a molar ration of 3:1 was prepared as a natural deep eutectic extracting solvent. Various extraction parameters such as the volume of the natural deep eutectic solvent, vortex duration, centrifugation duration, sample volume and pH were systematically explored and optimized. Determination coefficients of ≥0.9990 were achieved for the analyzed compounds under the optimal conditions. The limits detection were in the range of 0.0005 to 0.02 µg/L, while extraction recoveries ranged from 97.8 % to 100.2 % with relative standard deviations (%RSD) not exceeding 6.8 %. To assess the practical applicability of the proposed method, it was employed for the determination of five parabens and three bisphenols in eighty food products including soft drinks, energy drinks, sauces and juices collected from the Saudi market. The environmental implications of the proposed method were assessed using the following evaluation tools, Eco-Scale Assessment (ESA), Green Analytical Procedure Index (GAPI) and Analytical GREEnness metric (AGREE). To the best of our knowledge, this is the first study to determine the investigated analytes using anisaldehyde based deep eutectic solvent.

Morphology and formation mechanism of cracks in Al2O3–ZrO2 eutectic ceramics fabricated via laser powder bed fusion

AbstractThe cracks in Al2O3–ZrO2 eutectic ceramics produced by laser powder bed fusion (LPBF) have a significant impact on their practical applications in various industries. In order to understand the factors influencing crack formation, a systematic study of the characterization and propagation of cracks in single‐track, multi‐track, and bulk samples by varying the process parameters has been carried out in this research. The results showed that parallel cracks can be healed by reducing the scanning spacing and scanning length. Additionally, it was found that using a modest scanning speed and a shorter length can minimize the accumulation of thermal stress, resulting in the suppress crack formation. Based on this conclusion, a crack‐free Al2O3–ZrO2 eutectic ceramic sample was finally obtained under the optimized parameters with the power of 100 W, the scanning speed of 100 mm/s, the hatch spacing of 100 μm, the scanning length of 3 mm, and the layer thickness of 50 μm. Additionally, three typical microstructures, including eutectic, cellular, and dendritic structures, were identified in the LPBF‐fabricated Al2O3–ZrO2 samples. The cellular microstructure showed improved crack inhibition capability due to the deflection and pinning effects. Cracks expand more easily in dendritic and eutectic microstructures, where anisotropy is more prominent.

Hydrogen Transport Model in Eutectic PbLi for Data Evaluation in an Absorption-Desorption Experimental Facility

The determination of the transport parameters of the hydrogen isotopes in the eutectic lead-lithium (PbLi) alloy represents a key issue for the design of the different breeding blanket systems that are being developed based on this liquid metal. This is the case for the dual-coolant lithium-lead blanket where the values of the Sieverts’ constant and diffusivity will delimit the magnitude and the kinetics of the induced tritium flux produced by the breeding blanket toward the circuit of He for the refrigeration of the structures. In addition, the design (sizing and efficiency) of future tritium extraction systems of the breeding alloy or the He coolant purification system will be defined on the basis of these transport parameters. Taking into account the current literature, there exists a very wide band (even more than three orders of magnitude) in the experimental results for the Sieverts’ constant obtained by different research groups using different experimental techniques. This dispersion band in terms of solubility is not acceptable from the point of view of the design of a breeding blanket for a fusion reactor. With the aim of reducing this dispersion of results, the Absorption-Desorption facility available at the University of the Basque Country (UPV/EHU) has been upgraded and new samples of high quality PbLi will be measured in the near future in collaboration with CIEMAT. In this work, a complete theoretical model is described for the interaction between isotopes of hydrogen and the eutectic PbLi sample considering the particular boundary conditions for the absorption and desorption processes. This model has been specifically developed for the upgraded Absorption-Desorption facility available at the UPV/EHU, according to the new configuration of the experimental chamber made of glass and quartz and the geometry of the crucible made of tungsten that is designed to hold the PbLi sample. Three different phases are described (loading, pumping, and release) together with the boundary conditions that have been taken into account in each one. This way, different mathematical expressions for the concentration profile of the isotopes of hydrogen through the PbLi sample are posed for each phase so that the experimental measurements to be carried out in the upgraded Absorption-Desorption facility will be fitted to them, and as a result, the transport parameters will be obtained.

MICRONIZED EUTECTIC MIXTURE OF FENOFIBRIC ACID-SACCHARIN FORMATION FOR SOLUBILITY AND DISSOLUTION ENHANCEMENT

Objective: This study aims to increase the solubility and dissolution rate of fenofibric acid by forming a micronized eutectic mixture of fenofibric acid-saccharin with spray drying technique.
 Methods: Suspension of the eutectic mixture was prepared in ethanol: distilled water (3:1) followed by a spray drying method to obtain the microparticles. Microparticles characterization was performed by particle size analysis (PSA), powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), FT-IR spectroscopy, and scanning electron microscopy (SEM). Solubility test was carried out in CO2-free distilled water, meanwhile the dissolution rate study was conducted in phosphate buffer solution at pH 6.8.
 Results: The results showed the mean of the samples’ particle size was 72.29±7.33 µm. Compared to the intact fenofibric acid, the micronized eutectic mixture sample has a decreased melting point, fusion enthalpy, and crystallinity without any wavenumber shifted in the FT-IR spectra. The solubility of micronized eutectic mixture was 2.2 times higher than intact fenofibric acid, while the amount of micronized eutectic mixture dissolved at 60 min was 11.7 times higher.
 Conclusion: It can be concluded that the spray-dried micronized eutectic mixture of fenofibric acid-saccharin was having the ability to enhance the dissolution of fenofibric acid.

Dispersive liquid-liquid microextraction utilizing menthol-based deep eutectic solvent for simultaneous determination of sulfonamides residues in powdered milk-based infant formulas

An eco-friendly, fast, sensitive dispersive liquid–liquid microextraction (DLLME) method followed by UPLC-MS/MS was developed and validated for multi-residue determination of sulfonamides in milk-based infant and young children formulas. In this study, a natural deep eutectic solvent was synthesized using menthol and octanoic acid at a molar ratio of 1:2 for the extraction of seven sulfonamides in infant formulas. Different extraction parameters including volume of deep eutectic solvent, vortex time, centrifugation time, sample volume and pH were investigated and optimized. Under the optimum conditions, determination coefficients of ≥ 0.9993 were obtained for all studied analytes. The limits of detection ranged from 0.5 to 1.5 µg Kg−1. The extraction recoveries were in the range of 82.6–100.1% with RSDs %≤ 7.5. To investigate the applicability of the proposed method, it was applied to determination of the studied sulfonamides in thirty milk-based infant formulas of different brands. The environmental impact of the presented method was evaluated using three assessment tools namely: Eco-Scale Assessment (ESA), Green Analytical Procedure Index (GAPI) and Analytical GREEnness metric (AGREE). The characteristic performance of the developed DLLME-UPLC-MS/MS method was also compared with other reported methods.

A new green method employing ultrasonic-assisted liquid-phase microextraction and digital imaging colorimetry for the determination of mefenamic acid in medicinal products

A simple, fast, and low-cost method was developed to determine mefenamic acid in drug samples. Ultrasonic-assisted liquid-phase microextraction (UA-LPME) is applied to the preconcentration of mefenamic acid and subsequent detection by digital imaging colorimetry (DIC). The UA-LPME was performed with a eutectic solvent consisting of thymol and menthol (extraction solvent) and a solution of copper sulfate. Univariate optimization has been used to find the optimal working conditions. The variables studied were: copper sulfate concentration, eutectic solvent type, pH, sample volume, reaction time, and ultrasound time. The limit of detection obtained was 0.43 μg mL−1, and the precision (relative standard deviation) was 2.38%. The method was successfully applied to determine mefenamic acid in drug samples. The procedure follows the principles of green chemistry, as it uses small amounts of samples and reagents, generates few residues, and uses an environmentally friendly extraction solvent.

Silver as a capturing material for iodine released from lead\u2013bismuth eutectic in various conditions

The usage of silver as a filtering material for removal of iodine from the gas phase of a lead–bismuth eutectic based nuclear reactor was investigated in various atmospheres representing normal operation as well as accident conditions. Thermochromatography experiments were performed to quantify the retention experienced on a silver surface by iodine species evaporated from a lead–bismuth eutectic sample. Measured adsorption enthalpies ranged from −171 to − 208 kJ mol−1 with observed differences attributed to various surface effects rather than a change in iodine speciation. The postulated adsorption mechanism is chemisorption of iodine atoms on the silver surface. Metallic silver fulfills the desired criteria for a capturing material in water-free filtering systems to be used as an alternative to traditional alkaline scrubbers commonly used in LWR systems.

Deep eutectic solvent-based continuous sample drop flow microextraction combined with electrothermal atomic absorption spectrometry for speciation and determination of chromium ions in aqueous samples

Deep eutectic solvent-based continuous sample drop flow-microextraction technique along with electrothermal atomic absorption spectroscopy has been developed as a green procedure to extract and measure chromium (Cr) speciation in aqueous samples. The efficacy of the independent variables was evaluated on the extraction efficiency through chemometric methods in three steps. The methods indicated good linearity for the analyte (R2 = 0.9989). The analytical signal, under optimal conditions, was linear in the range of 0.1–20 μg L−1. The limit of detection and quantification was estimated at the concentration of 0.096 and 0.162 μg L−1, respectively. The precision like repeatability and reproducibility was assessed by calculating relative standard deviation (RSD %), and these values were lower than 4.1% and 12.6%, respectively. Consequently, the proposed procedure was used to extract and analyze Cr ion in real samples, indicating satisfactory recoveries (95.6–106.2%).

ESTIMATION OF HELIUM AND TRITIUM RELEASE FROM THE Li15.7Pb LEAD-LITHIUM EUTECTIC IN THE SOLID PHASE STATE UNDER IRRADIATION AT THE IVG.1M REACTOR

The studies described in this paper are devoted to the study of helium and tritium release formation in the solid phase state of new Li15.7Pb lithium-lead eutectic under irradiation. The paper describes the main properties of the new material and its microstructure. The comparison of microstructures of eutectic Li15.7Pb and Pb17Li is given. Helium and tritium free path length in the near-surface layer of the lead lithium eutectic sample were calculated. The rate of helium and tritium formation in this material during its irradiation at the IVG.1M reactor has been determined. Estimation of helium and tritium release formation from the near-surface layer of the Li15.7Pb lithium-lead eutectic has been done and a comparison with experimental data obtained in in-pile test has been presented.

Thiomalic acid/ferric chloride-based deep eutectic solvent for microextraction of chromium in natural water samples prior to FAAS analysis

ABSTRACT Deep eutectic solvents have become interested green materials for microextraction applications. In this study, a novel deep eutectic solvent have been formed by combination of thiomalic acid and ferric chloride in ethylene glycol medium, which then used for liquid–liquid microextraction of trace chromium from water samples. The microextraction process is donated the name of deep eutectic solvent-liquid liquid microextraction (DES-LLME). The microextraction procedure was optimised by evaluating the effect of pH, amount of deep eutectic solvent and sample volume. The optimum recoveries for chromium were achieved at pH 7.0, 200 µL of deep eutectic solvents, and sample volume up to 40 mL, with limits of detection and quantification of 1.18 µg·L−1 and 3.54 µg·L−1 respectively. By validating the DES-LLME with TMDA-53.3 fortified water reference materials, the chromium recovery was 99%.

Microstructural Analysis of CaO-Fe2O3 Heat Treated at Different Temperature

In present paper a study has been carried out to analyze the thermophysical properties and microstructural behavior of CaO.Fe2O3.A binary eutectic sample material is taken in the ratio of 22:78 by Wt. % in mixed powder form prepared manually. The sample powder is heat-treated at 950°C, 1050°C, and 1150°C for three hour holding time in programmable furnace. Further, the characterization is done with the help of different characterization technique like DSC, XRD, TGA to analyze its thermophysical properties and microstructural changes. This studies became necessary to analyze and interpret the data collected from prototype material found from nuclear severe accident occurred in the past. As heat transfer phenomena plays the crucial role in nuclear severe accident due to high temperature gradient developed inside the reactor vessel. Hence a non-prototype material is needed to study about heat transfer phenomena and in context of this study the material CaO.Fe2O3 is being considered. This study bears the first stage to validate the given material is simulant material. In the current study, heat absorbed, phase analysis, unit cell volume, melting point, crystallite size, dislocation density, and weight loss have been reported and analyzed.

A novel deep eutectic solvent microextraction procedure for enrichment, separation and atomic absorption spectrometric determination of palladium at ultra-trace levels in environmental samples

A dispersive deep eutectic solvent microextraction procedure for the separation and preconcentration of palladium from environmental samples has been established prior to its flame atomic absorption spectrometric determination. The deep eutectic solvent (DES) was prepared by mixing disodium 4,5-dihydroxy-1,3-benzenedisulfonate, hydroxyl ammonium chloride, FeCl3 and phenol resulting in homogenous solution which used directly for the extraction of palladium. The analytical parameter including pH, amount of deep eutectic solvent and sample volume were optimized. The developed microextraction procedure was found to have tolerance for the common matrix ions in real samples. The optimization studies resulted in pH was suitable at 6.0 with sample volume up to 35 mL. The preconcentration factor was 116. The detection limit was found as 1.18 µg·L−1. The presented microextraction method was applied to determination of palladium in marble mine and catalytic converter samples.

Deep eutectic solvent microextraction of lead(II), cobalt(II), nickel(II) and manganese(II) ions for the separation and preconcentration in some oil samples from Turkey prior to their microsampling flame atomic absorption spectrometric determination

A new liquid phase microextraction method based on deep eutectic solvent microextraction was developed for separation and preconcentration of lead, cobalt, nickel and manganese from edible oil samples like sunflower oil, baby oil, trout, waste frying oil and syrup-soaked pastry oil. A choline chloride deep eutectic solvent was used for microextraction. After extraction, analytical concentrations were determined by flame atomic absorption spectrometry. Effects of analytical parameters such as type and volume of deep eutectic solvent, sample volume, and temperature on extraction efficiency of lead, cobalt, nickel and manganese were optimized. The recoveries were generally >95%. The relative standard deviation (RSD, %, n = 7) of 50 μg/ L of analyte elements was in the range of 0.9–4.3%. Accuracy of presented microextraction method was checked by addition-recovery studies to oil samples. The presented deep eutectic solvent microextraction method was finally applied to edible oil samples and waste oils with different properties for the determination of analyte contents.

Estimation and Mode Selection of Deuterium Flux Supply into Ampoule Device Through Diffusion Filter in Experiments with Pb15.7Li Eutectic at the IVG1.M Reactor

One of the most promising materials to produce tritium in fuel cycle of fusion facilities is the lead-lithium eutectic Pb15.7Li. Tritium will be generated in nuclear reactions in a lithium-containing material under the influence of neutron irradiation. However, nowadays a limited number of studies have been conducted with the eutectic of such a composition (with a lithium content of 15.7%) and consequently, there is a lack of data on mechanisms of tritium generation and release from Pb15.7Li. In this regard, there is an urgent necessity for research of tritium generation and release from Pb15.7 Li directly under neutron irradiation conditions. For these studies a differential method will be used, which consists in follows: a controlled flux of spectrally pure deuterium will be continuously fed into the experimental cell with the eutectic sample during the reactor experiment. The regulated flux of deuterium will be fed to the experimental cell with the Pb15.7Li sample using diffusion palladium-silver filter. The article describes the process of determination of deuterium flux supply modes into the experimental cell. The temperature dependences of deuterium penetration through diffusion palladium-silver filter are presented. The coefficients of diffusion, solubility and permeability of deuterium through a palladium-silver filter are estimated and the activation energies of these processes as well as the Arrhenius dependence are presented.

The Nanometer-Sized Eutectic Structure of Si/CrSi2 Thermoelectric Materials Fabricated by Rapid Solidification

Nanostructuring is known to be an effective method to improve thermoelectric performance but, generally, it requires complex procedures and much labor. In the present study, self-assembled nanometer-sized composite structures of silicon (Si) and chromium disilicide (CrSi2) were easily fabricated by the rapid solidification of a melt with a eutectic composition. Ribbon-like samples were obtained with a dominant nanostructure of fine aligned lamellae with a spacing range of 20–35 nm. The thermoelectric power factor of the ribbon was observed to be 1.2 mW/mK2 at room temperature and reached 3.0 mW/mK2 at 773 K. The thermal conductivity was 65% lower than that of a bulk eutectic sample. The results suggest that this method is promising for fabricating an effective nanostructure for thermoelectric performance.

Thermodynamic reevaluation and experimental validation of the CsNO3-KNO3-NaNO3 system and its subsystems

Phase equilibria and thermodynamic properties of the CsNO3-KNO3-NaNO3 system and its three subsys-tems were optimized thermodynamically and validated experimentally. The liquid and end solid solution phases of the KNO3-NaNO3 and CsNO3-KNO3 systems were modeled using the substitutional solution and compound energy formalism models, respectively. The CsNO3-KNO3-NaNO3 ternary system was described thermodynamically based on the self-consistent thermodynamic parameters of the three binary systems. A set of thermodynamic parameters was obtained to reproduce the available information on the thermodynamic properties and phase equilibria. Melting temperature, enthalpy, and specific heat capacity of a eutectic sample were determined using differential scanning calorimetry(DSC). The results show a good consistency with the calculated results, suggesting the reliability of the current thermodynamic database. This work is useful for the construction of multicomponent nitrates and to provide guidance for the development of new medium for thermal energy storage.

Deep eutectic solvent-mediated extraction for ligand-less preconcentration of lead and cadmium from environmental samples using magnetic nanoparticles

A simple, rapid and eco-friendly deep eutectic solvent-modified magnetic nanoparticles extraction method has been reported for ligand-less separation/preconcentration of lead(II) and cadmium(II) for the first time. The metal ions interact with the deep eutectic solvent adhering to the magnetic nanoparticles. Trapped analytes can be easily desorbed with 1.0 M nitric acid and determined by flame atomic absorption spectrometry. The effects of pH value, type of deep eutectic solvent, sample volume, nature and concentration of desorbing solution, ionic strength and extraction time on the extraction were optimized. Under the optimized experimental conditions, the detection limits (defined as 3Sb/m) were 0.4 and 0.1 μg L−1 and the linear dynamic ranges were 2 to 250 μg L−1 and 0.5 to 30 μg L−1 for lead and cadmium, respectively. The relative standard deviations for six replicate measurements at 150 and 20 μg L−1 levels of lead and cadmium were 1.8 and 2.1 %, respectively. A sample volume of 60 mL resulted in a preconcentration factor of 100. The sorbent showed high capacity for lead (25.0 mg g−1) and cadmium (23.7 mg g−1). The method was successfully applied to the determination of lead and cadmium in soil, hair and several water samples.

Directionally solidified Al2O3–Yb3Al5O12 eutectics for selective emitters

Al2O3–Yb3Al5O12 eutectic rods were directionally solidified using the laser floating zone method at rates between 25 and 750mm/h. The microstructure consisted of an interpenetrated network of both eutectic phases for all the growth rates. The size of the phases was strongly dependent on the growth rate, the eutectic interspacing decreasing from 4.5μm at the lowest growth rate to 600nm at 750mm/h. The optical transmission of the sample with coarser microstructure was measured and compared with that of an Yb3Al5O12 single crystal grown “ad hoc” using the same method. The apparent “oscillator strength” of the single 2F7/2→2F5/2 Yb3+ absorption band was larger in the eutectic sample than in the single crystal, which was attributed to the increase in the light path caused by multiple refractions at the eutectic interphases. The thermal emission of the eutectic rod was studied between 1000°C and 1500°C. An intense and relatively narrow emission band at about 1μm corresponding to the 2F5/2→2F7/2 Yb3+ electronic transition was observed in the whole temperature range. The intensity of the band increased with the temperature up to about 1300°C. At higher temperatures a saturation of the selective emission was observed which was attributed to the competition between the increase in the thermal population of the excited state and the enhancement of the non-radiative de-excitation channels with the temperature.

Phase complex of the LiCl-NaCl-KCl-Sr(NO3)2 quaternary system and physicochemical properties of its eutectic mixture

For the first time, the coordinates of the invariant point of a eutectic sample in the LiCl-NaCl-KCl-Sr(NO3)2 quaternary system were determined by a calculation-experimental method, and the efficiency of this method was confirmed by thermal analysis. The temperature dependences of the specific density and electrical conductivity of the eutectic melt in the system were studied, and the volumetric expansion of this melt to the maximal working temperature was calculated.

Estimation Of Cooling Rates In Suction Casting And Copper-Mould Casting Processes

Abstract The cooling rates associated with suction and copper-mould casting of ø2, ø3 and ø5 mm rods made in Fe-25wt%Ni and Al-33wt%Cu alloys were determined based on their cellular and lamellar spacings, respectively. The work showed that the temperature profile in cylindrical samples can not be determined merely by microstructural examination of eutectic sample alloys. A concave solidification front, as a result of eutectic transformation, caused decrease of a lamellar spacing while approaching to the rod centre. The minimum axial cooling rates, estimated based on the cellular spacing in the Fe-25wt%Ni alloy, were evaluated to be about 200 K/s for both ø2 and ø3 mm and only 30 K/s for the ø5 mm suction cast rods. The corresponding values were slightly lower for the copper-mould cast rods.