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Sample records for ionic liquid-based ultrasound-assisted

  1. Determination of atenolol in human plasma using ionic-liquid-based ultrasound-assisted in situ solvent formation microextraction followed by high-performance liquid chromatography.

    Science.gov (United States)

    Zeeb, Mohsen; Farahani, Hadi; Papan, Mohammad Kazem

    2016-06-01

    An efficient analytical method called ionic-liquid-based ultrasound-assisted in situ solvent formation microextraction followed by high-performance liquid chromatography was developed for the determination of atenolol in human plasma. A hydrophobic ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) was formed by the addition of a hydrophilic ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate) to a sample solution containing an ion-pairing agent during microextraction. The analyte was extracted into the ionic liquid phase while the microextraction solvent was dispersed throughout the sample by utilizing ultrasound. The sample was then centrifuged, and the extracting phase retracted into the microsyringe and injected to liquid chromatography. After optimization, the calibration curve showed linearity in the range of 2-750 ng/mL with the regression coefficient corresponding to 0.998. The limits of detection (S/N = 3) and quantification (S/N = 10) were 0.5 and 2 ng/mL, respectively. A reasonable relative recovery range of 90-96.7% and satisfactory intra-assay (4.8-5.1%, n = 6) and interassay (5.0-5.6%, n = 9) precision along with a substantial sample clean-up demonstrated good performance of the procedure. It was applied for the determination of atenolol in human plasma after oral administration and some pharmacokinetic data were obtained. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Ionic liquid-based ultrasound-assisted dispersive liquid-liquid microextraction combined with electrothermal atomic absorption spectrometry for a sensitive determination of cadmium in water samples

    International Nuclear Information System (INIS)

    Li Shengqing; Cai Shun; Hu Wei; Chen Hao; Liu Hanlan

    2009-01-01

    A new method was developed for the determination of cadmium in water samples using ionic liquid-based ultrasound-assisted dispersive liquid-liquid microextraction (IL-based USA-DLLME) followed by electrothermal atomic absorption spectrometry (ETAAS). The IL-based USA-DLLME procedure is free of volatile organic solvents, and there is no need for a dispersive solvent, in contrast to conventional DLLME. The ionic liquid, 1-hexyl-3-methylimidazolium hexafluorophosphate (HMIMPF 6 ), was quickly disrupted by an ultrasonic probe for 1 min and dispersed in water samples like a cloud. At this stage, a hydrophobic cadmium-DDTC complex was formed and extracted into the fine droplets of HMIMPF 6 . After centrifugation, the concentration of the enriched cadmium in the sedimented phase was determined by ETAAS. Some effective parameters of the complex formation and microextraction, such as the concentration of the chelating agent, the pH, the volume of the extraction solvent, the extraction time, and the salt effect, have been optimized. Under optimal conditions, a high extraction efficiency and selectivity were reached for the extraction of 1.0 ng of cadmium in 10.0 mL of water solution employing 73 μL of HMIMPF 6 as the extraction solvent. The enrichment factor of the method is 67. The detection limit was 7.4 ng L - 1 , and the characteristic mass (m 0 , 0.0044 absorbance) of the proposed method was 0.02 pg for cadmium (Cd). The relative standard deviation (RSD) for 11 replicates of 50 ng L - 1 Cd was 3.3%. The method was applied to the analysis of tap, well, river, and lake water samples and the Environmental Water Reference Material GSBZ 50009-88 (200921). The recoveries of spiked samples were in the range of 87.2-106%.

  3. Ionic-liquid-based ultrasound-assisted extraction of isoflavones from Belamcanda chinensis and subsequent screening and isolation of potential α-glucosidase inhibitors by ultrafiltration and semipreparative high-performance liquid chromatography.

    Science.gov (United States)

    Li, Senlin; Li, Sainan; Huang, Yu; Liu, Chunming; Chen, Lina; Zhang, Yuchi

    2017-06-01

    The separation of a compound of interest from its structurally similar homologues to produce high-purity natural products is a challenging problem. This work proposes a novel method for the separation of iristectorigenin A from its structurally similar homologues by ionic-liquid-based ultrasound-assisted extraction and the subsequent screening and isolation of potential α-glucosidase inhibitors via ultrafiltration and semipreparative high-performance liquid chromatography. Ionic-liquid-based ultrasound-assisted extraction was successfully applied to the extraction of tectorigenin, iristectorigenin A, irigenin, and irisflorentin from Belamcanda chinensis. The optimum conditions for the efficient extraction of isoflavones were determined as 1.0 M 1-ethyl-3-methylimidazolium tetrafluoroborate with extraction time of 30 min and a solvent to solid ratio of 30 mL/g. Ultrafiltration with liquid chromatography and mass spectrometry was applied to screen and identify α-glucosidase inhibitors from B. chinensis, followed by the application of semipreparative high-performance liquid chromatography to separate and isolate the active constituents. Four major compounds including tectorigenin, iristectorigenin A, irigenin, and irisflorentin were screened and identified as α-glucosidase inhibitors, and then the four active compounds abovementioned were subsequently isolated by semipreparative high-performance liquid chromatography (99.89, 88.97, 99.79, and 99.97% purity, respectively). The results demonstrate that ionic liquid extraction can be successfully applied to the extraction of isoflavones from B. chinensis. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Extraction and reliable determination of acrylamide from thermally processed foods using ionic liquid-based ultrasound-assisted selective microextraction combined with spectrophotometry.

    Science.gov (United States)

    Altunay, Nail; Elik, Adil; Gürkan, Ramazan

    2018-02-01

    Acrylamide (AAm) is a carcinogenic chemical that can form in thermally processed foods by the Maillard reaction of glucose with asparagine. AAm can easily be formed especially in frequently consumed chips and cereal-based foods depending on processing conditions. Considering these properties of AAm, a new, simple and green method is proposed for the extraction of AAm from thermally processed food samples. In this study, an ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate, [Bmim][BF 4 ]) as extractant was used in the presence of a cationic phenazine group dye, 3,7-diamino-5-phenylphenazinium chloride (PSH + , phenosafranine) at pH 7.5 for the extraction of AAm as an ion-pair complex from selected samples. Under optimum conditions, the analytical features obtained for the proposed method were as follows; linear working range, the limits of detection (LOD, 3S b /m) and quantification (LOQ, 10S b /m), preconcentration factor, sensitivity enhancement factor, sample volume and recovery% were 2.2-350 µg kg -1 , 0.7 µg kg -1 , 2.3 µg kg -1 , 120, 95, 60 mL and 94.1-102.7%, respectively. The validity of the method was tested by analysis of two certified reference materials (CRMs) and intra-day and inter-day precision studies. Finally, the method was successfully applied to the determination of AAm levels in thermally processed foods using the standard addition method.

  5. Ultrasound-Assisted Extraction of Carnosic Acid and Rosmarinic Acid Using Ionic Liquid Solution from Rosmarinus officinalis

    Directory of Open Access Journals (Sweden)

    Chunjian Zhao

    2012-09-01

    Full Text Available Ionic liquid based, ultrasound-assisted extraction was successfully applied to the extraction of phenolcarboxylic acids, carnosic acid and rosmarinic acid, from Rosmarinus officinalis. Eight ionic liquids, with different cations and anions, were investigated in this work and [C8mim]Br was selected as the optimal solvent. Ultrasound extraction parameters, including soaking time, solid–liquid ratio, ultrasound power and time, and the number of extraction cycles, were discussed by single factor experiments and the main influence factors were optimized by response surface methodology. The proposed approach was demonstrated as having higher efficiency, shorter extraction time and as a new alternative for the extraction of carnosic acid and rosmarinic acid from R. officinalis compared with traditional reference extraction methods. Ionic liquids are considered to be green solvents, in the ultrasound-assisted extraction of key chemicals from medicinal plants, and show great potential.

  6. Design of guanidinium ionic liquid based microwave-assisted extraction for the efficient extraction of Praeruptorin A from Radix peucedani.

    Science.gov (United States)

    Ding, Xueqin; Li, Li; Wang, Yuzhi; Chen, Jing; Huang, Yanhua; Xu, Kaijia

    2014-12-01

    A series of novel tetramethylguanidinium ionic liquids and hexaalkylguanidinium ionic liquids have been synthesized based on 1,1,3,3-tetramethylguanidine. The structures of the ionic liquids were confirmed by (1)H NMR spectroscopy and mass spectrometry. A green guanidinium ionic liquid based microwave-assisted extraction method has been developed with these guanidinium ionic liquids for the effective extraction of Praeruptorin A from Radix peucedani. After extraction, reversed-phase high-performance liquid chromatography with UV detection was employed for the analysis of Praeruptorin A. Several significant operating parameters were systematically optimized by single-factor and L9 (3(4)) orthogonal array experiments. The amount of Praeruptorin A extracted by [1,1,3,3-tetramethylguanidine]CH2CH(OH)COOH is the highest, reaching 11.05 ± 0.13 mg/g. Guanidinium ionic liquid based microwave-assisted extraction presents unique advantages in Praeruptorin A extraction compared with guanidinium ionic liquid based maceration extraction, guanidinium ionic liquid based heat reflux extraction and guanidinium ionic liquid based ultrasound-assisted extraction. The precision, stability, and repeatability of the process were investigated. The mechanisms of guanidinium ionic liquid based microwave-assisted extraction were researched by scanning electron microscopy and IR spectroscopy. All the results show that guanidinium ionic liquid based microwave-assisted extraction has a huge potential in the extraction of bioactive compounds from complex samples. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Ionic liquid ultrasound assisted dispersive liquid-liquid microextraction method for preconcentration of trace amounts of rhodium prior to flame atomic absorption spectrometry determination

    Energy Technology Data Exchange (ETDEWEB)

    Molaakbari, Elaheh [Chemistry Department, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Young Research Society, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Mostafavi, Ali, E-mail: mostafavi.ali@gmail.com [Chemistry Department, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Afzali, Daryoush [Environment and Nanochemistry Department, Research Institute of Environmental Science, International Center for Science, High Technology and Environmental Science, Kerman (Iran, Islamic Republic of); Mineral Industries Research Center, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of)

    2011-01-30

    In this article, we consider ionic liquid based ultrasound-assisted dispersive liquid-liquid microextraction of trace amounts of rhodium from aqueous samples and show that this is a fast and reliable sample pre-treatment for the determination of rhodium ions by flame atomic absorption spectrometry. The Rh(III) was transferred into its complex with 2-(5-bromo-2-pyridylazo)-5-diethylamino phenol as a chelating agent, and an ultrasonic bath with the ionic liquid, 1-octyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide at room temperature was used to extract the analyte. The centrifuged rhodium complex was then enriched in the form of ionic liquid droplets and prior to its analysis by flame atomic absorption spectrometry, 300 {mu}L ethanol was added to the ionic liquid-rich phase. Finally, the influence of various parameters on the recovery of Rh(III) was optimized. Under optimum conditions, the calibration graph was linear in the range of 4.0-500.0 ng mL{sup -1}, the detection limit was 0.37 ng mL{sup -1} (3S{sub b}/m, n = 7) and the relative standard deviation was {+-}1.63% (n = 7, C = 200 ng mL{sup -1}). The results show that ionic liquid based ultrasound assisted dispersive liquid-liquid microextraction, combined with flame atomic absorption spectrometry, is a rapid, simple, sensitive and efficient analytical method for the separation and determination of trace amounts of Rh(III) ions with minimum organic solvent consumption.

  8. Ionic liquid based multifunctional double network gel

    Science.gov (United States)

    Ahmed, Kumkum; Higashihara, Tomoya; Arafune, Hiroyuki; Kamijo, Toshio; Morinaga, Takashi; Sato, Takaya; Furukawa, Hidemitsu

    2015-04-01

    Gels are a promising class of soft and wet materials with diverse application in tissue engineering and bio-medical purpose. In order to accelerate the development of gels, it is required to synthesize multi-functional gels of high mechanical strength, ultra low surface friction and suitable elastic modulus with a variety of methods and new materials. Among many types of gel ionic gel made from ionic liquids (ILs) could be used for diverse applications in electrochemical devices and in the field of tribology. IL, a promising materials for lubrication, is a salt with a melting point lower than 100 °C. As a lubricant, ILs are characterized by an extremely low vapor pressure, high thermal stability and high ion conductivity. In this work a novel approach of making double network DN ionic gel using IL has been made utilizing photo polymerization process. A hydrophobic monomer Methyl methacrylate (MMA) has been used as a first network and a hydrophobic IL monomer, N,N-diethyl-N-(2-mthacryloylethyl)-N-methylammonium bistrifluoromethylsulfonyl)imide (DEMM-TFSI) has been used as a second network using photo initiator benzophenon and crosslinker triethylene glycol dimethacrylate (TEGDMA). The resulting DN ionic gel shows transparency, flexibility, high thermal stability, good mechanical toughness and low friction coefficient value which can be a potential candidate as a gel slider in different mechanical devices and can open a new area in the field of gel tribology.

  9. Removal of residual functionalized ionic liquids from water by ultrasound-assisted zero-valent iron/activated carbon.

    Science.gov (United States)

    Zhou, Haimei; Lv, Ping; Qi, Hang; Ma, Jinqi; Wang, Jianji

    2018-03-02

    Numerous applications of ionic liquids (ILs) are often accompanied by the generation of aqueous wastes. Due to the high toxicity and poor biodegradability of ILs, effective chemical treatment is of great importance for their removal from aqueous solution. In this work, an ultrasound-assisted zero-valent iron/activated carbon (US-ZVI/AC) micro-electrolysis technique was used to degrade residual functionalized ILs, 1-butyl-3-methyl benzimidazolium bromide ([BMBIM]Br) and 1-allyl-3-methylimidazolium chloride ([AMIM]Cl) in aqueous solution, and the degradation degree, degradation kinetics and possible degradation pathways were investigated. It was shown that the degradation of these functionalized ILs was highly efficient in the US-ZVI/AC system, and the degradation degree was as high as 96.1% and 92.9% in 110 min for [BMBIM]Br and [AMIM]Cl, respectively. The degradation of [BMBIM]Br could be described by the second-order kinetics model, and [BMBIM] + was decomposed in two ways: (i) sequential cleavage of N-alkyl side chain of the cation produced three intermediates; (ii) the 2-positioned H atoms of the benzimidazolium ring were first oxidized, and then the imidazolium ring was opened. The degradation of [AMIM]Cl followed the first-order kinetics rule, and the 2,4,5-positioned H atoms of the imidazolium ring were oxidized to induce ring opening. In addition, the removal of total organic carbon was found to be >87%, which indicates that most of the ILs was mineralized in the degradation process. These results suggest that ultrasound-assisted ZVI/AC micro-electrolysis is highly effective for the removal of residual functionalized ILs from aqueous environment.

  10. Impurity effects on ionic-liquid-based supercapacitors

    International Nuclear Information System (INIS)

    Liu, Kun; Lian, Cheng; Henderson, Douglas; Wu, Jianzhong

    2016-01-01

    Small amounts of an impurity may affect the key properties of an ionic liquid and such effects can be dramatically amplified when the electrolyte is under confinement. Here the classical density functional theory is employed to investigate the impurity effects on the microscopic structure and the performance of ionic-liquid-based electrical double-layer capacitors, also known as supercapacitors. Using a primitive model for ionic species, we study the effects of an impurity on the double layer structure and the integral capacitance of a room temperature ionic liquid in model electrode pores and find that an impurity strongly binding to the surface of a porous electrode can significantly alter the electric double layer structure and dampen the oscillatory dependence of the capacitance with the pore size of the electrode. Meanwhile, a strong affinity of the impurity with the ionic species affects the dependence of the integral capacitance on the pore size. Up to 30% increase in the integral capacitance can be achieved even at a very low impurity bulk concentration. As a result, by comparing with an ionic liquid mixture containing modified ionic species, we find that the cooperative effect of the bounded impurities is mainly responsible for the significant enhancement of the supercapacitor performance.

  11. Impurity effects on ionic-liquid-based supercapacitors

    Science.gov (United States)

    Liu, Kun; Lian, Cheng; Henderson, Douglas; Wu, Jianzhong

    2017-02-01

    Small amounts of an impurity may affect the key properties of an ionic liquid and such effects can be dramatically amplified when the electrolyte is under confinement. Here the classical density functional theory is employed to investigate the impurity effects on the microscopic structure and the performance of ionic-liquid-based electrical double-layer capacitors, also known as supercapacitors. Using a primitive model for ionic species, we study the effects of an impurity on the double layer structure and the integral capacitance of a room temperature ionic liquid in model electrode pores and find that an impurity strongly binding to the surface of a porous electrode can significantly alter the electric double layer structure and dampen the oscillatory dependence of the capacitance with the pore size of the electrode. Meanwhile, a strong affinity of the impurity with the ionic species affects the dependence of the integral capacitance on the pore size. Up to 30% increase in the integral capacitance can be achieved even at a very low impurity bulk concentration. By comparing with an ionic liquid mixture containing modified ionic species, we find that the cooperative effect of the bounded impurities is mainly responsible for the significant enhancement of the supercapacitor performance.

  12. Ionic liquid-based materials: a platform to design engineered CO2 separation membranes.

    Science.gov (United States)

    Tomé, Liliana C; Marrucho, Isabel M

    2016-05-21

    During the past decade, significant advances in ionic liquid-based materials for the development of CO2 separation membranes have been accomplished. This review presents a perspective on different strategies that use ionic liquid-based materials as a unique tuneable platform to design task-specific advanced materials for CO2 separation membranes. Based on compilation and analysis of the data hitherto reported, we provide a judicious assessment of the CO2 separation efficiency of different membranes, and highlight breakthroughs and key challenges in this field. In particular, configurations such as supported ionic liquid membranes, polymer/ionic liquid composite membranes, gelled ionic liquid membranes and poly(ionic liquid)-based membranes are detailed, discussed and evaluated in terms of their efficiency, which is attributed to their chemical and structural features. Finally, an integrated perspective on technology, economy and sustainability is provided.

  13. Determination of antimony and tin in beverages using inductively coupled plasma-optical emission spectrometry after ultrasound-assisted ionic liquid dispersive liquid-liquid phase microextraction.

    Science.gov (United States)

    Biata, N Raphael; Nyaba, Luthando; Ramontja, James; Mketo, Nomvano; Nomngongo, Philiswa N

    2017-12-15

    The aim of this study was to develop a simple and fast ultrasound-assisted ionic liquid dispersive liquid-liquid phase microextraction (UA-IL-DLLME) method for preconcetration of trace antimony and tin in beverage samples. The novelty of this study was based on the application of ligandless UA-IL-DLLME using low-density ionic liquid and organic solvents for preconcentration of Sb and Sn. The concentration of Sb and Sn were quantified using ICP-OES. Under the optimum conditions, the calibration graph was found to be LOQ-250µgL -1 (r 2 =0.9987) for Sb and LOQ-350µgL -1 for Sn. The LOD and LOQ of Sb and Sn ranged from 1.2to 2.5ngL -1 and 4.0 to 8.3ngL -1 , respectively, with high preconcentration factors. The precisions (%RSD) of the proposed method ranged from 2.1% to 2.5% and 3.9% to 4.7% for Sb and Sn, respectively. The proposed method was successfully applied for determination of Sb and Sn in beverages. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Ultrasound-assisted ionic liquid dispersive liquid-liquid microextraction combined with graphite furnace atomic absorption spectrometric for selenium speciation in foods and beverages.

    Science.gov (United States)

    Tuzen, Mustafa; Pekiner, Ozlem Zeynep

    2015-12-01

    A rapid and environmentally friendly ultrasound assisted ionic liquid dispersive liquid liquid microextraction (USA-IL-DLLME) was developed for the speciation of inorganic selenium in beverages and total selenium in food samples by using graphite furnace atomic absorption spectrometry. Some analytical parameters including pH, amount of complexing agent, extraction time, volume of ionic liquid, sample volume, etc. were optimized. Matrix effects were also investigated. Enhancement factor (EF) and limit of detection (LOD) for Se(IV) were found to be 150 and 12 ng L(-1), respectively. The relative standard deviation (RSD) was found 4.2%. The accuracy of the method was confirmed with analysis of LGC 6010 Hard drinking water and NIST SRM 1573a Tomato leaves standard reference materials. Optimized method was applied to ice tea, soda and mineral water for the speciation of Se(IV) and Se(VI) and some food samples including beer, cow's milk, red wine, mixed fruit juice, date, apple, orange, grapefruit, egg and honey for the determination of total selenium. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Ionic Liquid-Based Ultrasonic/Microwave-Assisted Extraction of ...

    African Journals Online (AJOL)

    Conclusion: Compared with traditional methods, IL-UMAE method uses Ionic liquid-solvent which greatly shortens the extraction time. IL-UMAE as a simple, effective and environmentally friendly approach shows a broad prospect for active ingredient extraction. Keywords: Dioscorea zingiberensis Steroidal saponins, Ionic ...

  16. Ionic Liquid-Based Optical and Electrochemical Carbon Dioxide Sensors

    Science.gov (United States)

    Behera, Kamalakanta; Pandey, Shubha; Kadyan, Anu; Pandey, Siddharth

    2015-01-01

    Due to their unusual physicochemical properties (e.g., high thermal stability, low volatility, high intrinsic conductivity, wide electrochemical windows and good solvating ability), ionic liquids have shown immense application potential in many research areas. Applications of ionic liquid in developing various sensors, especially for the sensing of biomolecules, such as nucleic acids, proteins and enzymes, gas sensing and sensing of various important ions, among other chemosensing platforms, are currently being explored by researchers worldwide. The use of ionic liquids for the detection of carbon dioxide (CO2) gas is currently a major topic of research due to the associated importance of this gas with daily human life. This review focuses on the application of ionic liquids in optical and electrochemical CO2 sensors. The design, mechanism, sensitivity and detection limit of each type of sensor are highlighted in this review. PMID:26690155

  17. Ionic Liquid-Based Optical and Electrochemical Carbon Dioxide Sensors.

    Science.gov (United States)

    Behera, Kamalakanta; Pandey, Shubha; Kadyan, Anu; Pandey, Siddharth

    2015-12-04

    Due to their unusual physicochemical properties (e.g., high thermal stability, low volatility, high intrinsic conductivity, wide electrochemical windows and good solvating ability), ionic liquids have shown immense application potential in many research areas. Applications of ionic liquid in developing various sensors, especially for the sensing of biomolecules, such as nucleic acids, proteins and enzymes, gas sensing and sensing of various important ions, among other chemosensing platforms, are currently being explored by researchers worldwide. The use of ionic liquids for the detection of carbon dioxide (CO₂) gas is currently a major topic of research due to the associated importance of this gas with daily human life. This review focuses on the application of ionic liquids in optical and electrochemical CO₂ sensors. The design, mechanism, sensitivity and detection limit of each type of sensor are highlighted in this review.

  18. Ionic Liquid-Based Optical and Electrochemical Carbon Dioxide Sensors

    Directory of Open Access Journals (Sweden)

    Kamalakanta Behera

    2015-12-01

    Full Text Available Due to their unusual physicochemical properties (e.g., high thermal stability, low volatility, high intrinsic conductivity, wide electrochemical windows and good solvating ability, ionic liquids have shown immense application potential in many research areas. Applications of ionic liquid in developing various sensors, especially for the sensing of biomolecules, such as nucleic acids, proteins and enzymes, gas sensing and sensing of various important ions, among other chemosensing platforms, are currently being explored by researchers worldwide. The use of ionic liquids for the detection of carbon dioxide (CO2 gas is currently a major topic of research due to the associated importance of this gas with daily human life. This review focuses on the application of ionic liquids in optical and electrochemical CO2 sensors. The design, mechanism, sensitivity and detection limit of each type of sensor are highlighted in this review.

  19. Ionic Liquid-Based Optical and Electrochemical Carbon Dioxide Sensors

    OpenAIRE

    Kamalakanta Behera; Shubha Pandey; Anu Kadyan; Siddharth Pandey

    2015-01-01

    Due to their unusual physicochemical properties (e.g., high thermal stability, low volatility, high intrinsic conductivity, wide electrochemical windows and good solvating ability), ionic liquids have shown immense application potential in many research areas. Applications of ionic liquid in developing various sensors, especially for the sensing of biomolecules, such as nucleic acids, proteins and enzymes, gas sensing and sensing of various important ions, among other chemosensing platforms, ...

  20. Particle self-assembly at ionic liquid-based interfaces.

    Science.gov (United States)

    Frost, Denzil S; Nofen, Elizabeth M; Dai, Lenore L

    2014-04-01

    This review presents an overview of the nature of ionic liquid (IL)-based interfaces and self-assembled particle morphologies of IL-in-water, oil- and water-in-IL, and novel IL-in-IL Pickering emulsions with emphasis on their unique phenomena, by means of experimental and computational studies. In IL-in-water Pickering emulsions, particles formed monolayers at ionic liquid-water interfaces and were close-packed on fully covered emulsion droplets or aggregated on partially covered droplets. Interestingly, other than equilibrating at the ionic liquid-water interfaces, microparticles with certain surface chemistries were extracted into the ionic liquid phase with a high efficiency. These experimental findings were supported by potential of mean force calculations, which showed large energy drops as hydrophobic particles crossed the interface into the IL phase. In the oil- and water-in-IL Pickering emulsions, microparticles with acidic surface chemistries formed monolayer bridges between the internal phase droplets rather than residing at the oil/water-ionic liquid interfaces, a significant deviation from traditional Pickering emulsion morphology. Molecular dynamics simulations revealed aspects of the mechanism behind this bridging phenomenon, including the role of the droplet phase, surface chemistry, and inter-particle film. Novel IL-in-IL Pickering emulsions exhibited an array of self-assembled morphologies including the previously observed particle absorption and bridging phenomena. The appearance of these morphologies depended on the particle surface chemistry as well as the ILs used. The incorporation of particle self-assembly with ionic liquid science allows for new applications at the intersection of these two fields, and have the potential to be numerous due to the tunability of the ionic liquids and particles incorporated, as well as the particle morphology by combining certain groups of particle surface chemistry, IL type (protic or aprotic), and whether oil

  1. Capturing CO2: conventional versus ionic-liquid based technologies

    International Nuclear Information System (INIS)

    Privalova, E I; Mäki-Arvela, P; Murzin, Dmitry Yu; Mikkhola, J P

    2012-01-01

    Since CO 2 facilitates pipeline corrosion and contributes to a decrease of the calorific value of gaseous fuels, its removal has become an issue of significant economic importance. The present review discusses various types of traditional CO 2 capture technologies in terms of their efficiency, complexity in system design, costs and environmental impact. The focus is hereby not only on conventional approaches but also on emerging 'green' solvents such as ionic liquids. The suitability of different ionic liquids as gas separation solvents is discussed in the present review and a description on their synthesis and properties in terms of CO 2 capture is provided. The bibliography includes 136 references.

  2. Selective determination of inorganic cobalt in nutritional supplements by ultrasound-assisted temperature-controlled ionic liquid dispersive liquid phase microextraction and electrothermal atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Berton, Paula; Martinis, Estefanía M.; Martinez, Luis D.; Wuilloud, Rodolfo G.

    2012-01-01

    Highlights: ► Synergy of ultrasound energy and TILDLME technique for improved metal extraction. ► Highly selective determination of inorganic Co species at trace levels. ► Speciation analysis of Co in several nutritional supplements with highly complex matrices. ► Development of an environmentally friendly microextraction technique with minimal waste production and sample consumption. - Abstract: In the present work, a simple and rapid analytical method based on application of ionic liquids (ILs) for inorganic Co(II) species (iCo) microextraction in a variety of nutrient supplements was developed. Inorganic Co was initially chelated with 1-nitroso-2-naphtol (1N2N) reagent followed by a modern technique named ultrasound-assisted temperature-controlled ionic liquid dispersive liquid phase microextraction (USA-TILDLME). The extraction was performed with 1-hexyl-3-methylimidazolium hexafluorophosphate [C 6 mim][PF 6 ] with the aid of ultrasound to improve iCo recovery. Finally, the iCo-enriched IL phase was solubilized in methanol and directly injected into an electrothermal atomic absorption spectrometer (ETAAS). Several parameters that could influence iCo microextraction and detection were carefully studied. Since the main difficulty in these samples is caused by high concentrations of potential interfering ions, different approaches were evaluated to eliminate interferences. The limit of detection (LOD) was 5.4 ng L −1 , while the relative standard deviation (RSD) was 4.7% (at 0.5 μg L −1 Co level and n = 10), calculated from the peak height of absorbance signals. Selective microextraction of iCo species was achieved only by controlling the pH value during the procedure. The method was thus successfully applied for determination of iCo species in nutritional supplements.

  3. Selective determination of inorganic cobalt in nutritional supplements by ultrasound-assisted temperature-controlled ionic liquid dispersive liquid phase microextraction and electrothermal atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Berton, Paula; Martinis, Estefania M. [Analytical Chemistry Research and Development Group (QUIANID), (LISAMEN-CCT-CONICET-Mendoza), Av. Ruiz Leal S/N Parque General San Martin, M 5502 IRA Mendoza (Argentina); Martinez, Luis D. [INQUISAL-CONICET, Departamento de Quimica Analitica, Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, San Luis (Argentina); Wuilloud, Rodolfo G., E-mail: rwuilloud@mendoza-conicet.gob.ar [Analytical Chemistry Research and Development Group (QUIANID), (LISAMEN-CCT-CONICET-Mendoza), Av. Ruiz Leal S/N Parque General San Martin, M 5502 IRA Mendoza (Argentina); Instituto de Ciencias Basicas, Universidad Nacional de Cuyo, Mendoza (Argentina)

    2012-02-03

    Highlights: Black-Right-Pointing-Pointer Synergy of ultrasound energy and TILDLME technique for improved metal extraction. Black-Right-Pointing-Pointer Highly selective determination of inorganic Co species at trace levels. Black-Right-Pointing-Pointer Speciation analysis of Co in several nutritional supplements with highly complex matrices. Black-Right-Pointing-Pointer Development of an environmentally friendly microextraction technique with minimal waste production and sample consumption. - Abstract: In the present work, a simple and rapid analytical method based on application of ionic liquids (ILs) for inorganic Co(II) species (iCo) microextraction in a variety of nutrient supplements was developed. Inorganic Co was initially chelated with 1-nitroso-2-naphtol (1N2N) reagent followed by a modern technique named ultrasound-assisted temperature-controlled ionic liquid dispersive liquid phase microextraction (USA-TILDLME). The extraction was performed with 1-hexyl-3-methylimidazolium hexafluorophosphate [C{sub 6}mim][PF{sub 6}] with the aid of ultrasound to improve iCo recovery. Finally, the iCo-enriched IL phase was solubilized in methanol and directly injected into an electrothermal atomic absorption spectrometer (ETAAS). Several parameters that could influence iCo microextraction and detection were carefully studied. Since the main difficulty in these samples is caused by high concentrations of potential interfering ions, different approaches were evaluated to eliminate interferences. The limit of detection (LOD) was 5.4 ng L{sup -1}, while the relative standard deviation (RSD) was 4.7% (at 0.5 {mu}g L{sup -1} Co level and n = 10), calculated from the peak height of absorbance signals. Selective microextraction of iCo species was achieved only by controlling the pH value during the procedure. The method was thus successfully applied for determination of iCo species in nutritional supplements.

  4. Ionic-Liquid Based Separation of Azeotropic Mixtures

    DEFF Research Database (Denmark)

    Kulajanpeng, Kusuma; Suriyapraphadilok, Uthaiporn; Gani, Rafiqul

    2014-01-01

    methodology for the screening of ionic liquids (ILs) as entrainers for ILs-based separation processes in binary aqueous azeotropic systems (e.g., water + ethanol and water + isopropanol) is presented. Ionic liquids as entrainers were first screened based on a combination of criteria such as stabi......methodology for the screening of ionic liquids (ILs) as entrainers for ILs-based separation processes in binary aqueous azeotropic systems (e.g., water + ethanol and water + isopropanol) is presented. Ionic liquids as entrainers were first screened based on a combination of criteria...... [C1MIM][DMP]. For the final evaluation, the best candidates for aqueous systems were used as entrainers, and then the vapor-liquid equilibrium (VLE) of the ternary systems containing ILs was predicted by the Non Random Two Liquids (NRTL) model to confirm the breaking of the azeotrope. Based...... on minimum concentration of the ILs required to break the given azeotrope, the best ILs as entrainers for water + ethanol and water + isopropanol azeotropic mixtures were [C1MIM][DMP] and [C2MIM][N(CN)2], respectively....

  5. Electrode Materials for Ionic Liquid Based-Supercapacitors

    OpenAIRE

    Lazzari, Mariachiara

    2010-01-01

    The development of safe, high energy and power electrochemical energy-conversion systems can be a response to the worldwide demand for a clean and low-fuel-consuming transport. This thesis work, starting from a basic studies on the ionic liquid (IL) electrolytes and carbon electrodes and concluding with tests on large-size IL-based supercapacitor prototypes demonstrated that the IL-based asymmetric configuration (AEDLCs) is a powerful strategy to develop safe, high-energy supercapacitors that...

  6. Lithium conducting ionic liquids based on lithium borate salts

    Energy Technology Data Exchange (ETDEWEB)

    Zygadlo-Monikowska, E.; Florjanczyk, Z.; Sluzewska, K.; Ostrowska, J.; Langwald, N.; Tomaszewska, A. [Warsaw University of Technology, Faculty of Chemistry, ul. Noakowskiego 3, 00-664 Warsaw (Poland)

    2010-09-15

    The simple reaction of trialkoxyborates with butyllithium resulted in the obtaining of new lithium borate salts: Li{l_brace}[CH{sub 3}(OCH{sub 2}CH{sub 2}){sub n}O]{sub 3}BC{sub 4}H{sub 9}{r_brace}, containing oxyethylene substituents (EO) of n=1, 2, 3 and 7. Salts of n {>=} 2 show properties of room temperature ionic liquid (RTIL) of low glass transition temperature, T{sub g} of the order from -70 to -80 C. The ionic conductivity of the salts depends on the number of EO units, the highest conductivity is shown by the salt with n = 3; in bulk its ambient temperature conductivity is 2 x 10{sup -5} S cm{sup -1} and in solution in cyclic propylene sulfite or EC/PC mixture, conductivity increases by an order of magnitude. Solid polymer electrolytes with borate salts over a wide concentration range, from 10 to 90 mol.% were obtained and characterized. Three types of polymeric matrices: poly(ethylene oxide) (PEO), poly(trimethylene carbonate) (PTMC) and two copolymers of acrylonitrile and butyl acrylate p(AN-BuA) were used in them as polymer matrices. It has been found that for systems of low salt concentration (10 mol.%) the best conducting properties were shown by solid polymer electrolytes with PEO, whereas for systems of high salt concentration, of the polymer-in-salt type, good results were achieved for PTMC as polymer matrix. (author)

  7. Ionic Liquid based polymer electrolytes for electrochemical sensors

    Directory of Open Access Journals (Sweden)

    Jakub Altšmíd

    2015-09-01

    Full Text Available Amperometric NO2 printed sensor with a new type of solid polymer electrolyte and a carbon working electrode has been developed. The electrolytes based on 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonylimide [EMIM][N(Tf2], 1-butyl-3-methylimidazolium trifluoromethanesulfonate [BMIM][CF3SO3] and 1-ethyl-3-methylimidazolium tetrafluoroborate [EMIM][BF4] ionic liquids were immobilized in poly(vinylidene fluoride matrix [PVDF]. The analyte, gaseous nitrogen dioxide, was detected by reduction at -500 mV vs. platinum pseudoreference electrode. The sensors showed a linear behavior in the whole tested range, i.e., 0 - 5 ppm and their sensitivities were in order of 0.3 x∙10-6 A/ppm. The sensor sensitivity was influenced by the electric conductivity of printing formulation; the higher the conductivity, the higher the sensor sensitivity. The rise/recovery times were in order of tens of seconds. The use of  screen printing technology and platinum pseudoreference electrode simplify the sensor fabrication and it does not have any negative effect on the sensor stability.DOI: http://dx.doi.org/10.5755/j01.ms.21.3.7371

  8. Solvent extraction of gold using ionic liquid based process

    Science.gov (United States)

    Makertihartha, I. G. B. N.; Zunita, Megawati; Rizki, Z.; Dharmawijaya, P. T.

    2017-01-01

    In decades, many research and mineral processing industries are using solvent extraction technology for metal ions separation. Solvent extraction technique has been used for the purification of precious metals such as Au and Pd, and base metals such as Cu, Zn and Cd. This process uses organic compounds as solvent. Organic solvents have some undesired properties i.e. toxic, volatile, excessive used, flammable, difficult to recycle, low reusability, low Au recovery, together with the problems related to the disposal of spent extractants and diluents, even the costs associated with these processes are relatively expensive. Therefore, a lot of research have boosted into the development of safe and environmentally friendly process for Au separation. Ionic liquids (ILs) are the potential alternative for gold extraction because they possess several desirable properties, such as a the ability to expanse temperature process up to 300°C, good solvent properties for a wide range of metal ions, high selectivity, low vapor pressures, stability up to 200°C, easy preparation, environmentally friendly (commonly called as "green solvent"), and relatively low cost. This review paper is focused in investigate of some ILs that have the potentials as solvent in extraction of Au from mineral/metal alloy at various conditions (pH, temperature, and pressure). Performances of ILs extraction of Au are studied in depth, i.e. structural relationship of ILs with capability to separate Au from metal ions aggregate. Optimal extraction conditon in order to gain high percent of Au in mineral processing is also investigated.

  9. Electrochemical deposition of magnesium from analogous ionic liquid based on dimethylformamide

    International Nuclear Information System (INIS)

    Wang, Huaiyou; Jia, Yongzhong; Wang, Xiaohua; Yao, Ying; Yue, Duyuan; Jing, Yan

    2013-01-01

    In this paper, a homogeneous, colorless analogous ionic liquid containing dimethylformamide (DMF) and magnesium chloride hexahydrate is synthesized. The conductivity of analogous ionic liquid is measured as a function of temperature and composition. Irreversible electrochemical behavior was generally observed by cyclic voltammetry (CV) in the analogous ionic liquid based electrolytes containing simple Mg salt. CV also shows that the reducing reaction of Mg 2+ is a diffusion control process. Electrochemical impedance spectroscopy (EIS) of analogous ionic liquid was measured at 20 °C, 40 °C and 60 °C. Electrodeposition of magnesium metal from analogous ionic liquid has been studied. The Mg deposits are also systematically characterized by the techniques of powder X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). Results showed that magnesium was found in the deposited film

  10. Evaluation of carbon fiber composites fabricated using ionic liquid based epoxies for cryogenic fluid applications

    Directory of Open Access Journals (Sweden)

    R.N. Grugel

    Full Text Available Utilizing tanks fabricated from fiber reinforced polymeric composites for storing cryogenic fluids such as liquid oxygen and liquid hydrogen is of great interest to NASA as considerable weight savings can be gained. Unfortunately such composites, especially at cryogenic temperatures, develop a mismatch that initiates detrimental delamination and crack growth, which promotes leaking. On-going work with ionic liquid-based epoxies appears promising in mitigating these detrimental effects. Some recent results are presented and discussed. Keywords: Ionic liquid, Carbon fiber, Epoxy, COPV, Cryogenic fluids

  11. Application of ionic liquids based enzyme-assisted extraction of chlorogenic acid from Eucommia ulmoides leaves

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Tingting; Sui, Xiaoyu, E-mail: suixiaoyu@outlook.com; Li, Li; Zhang, Jie; Liang, Xin; Li, Wenjing; Zhang, Honglian; Fu, Shuang

    2016-01-15

    A new approach for ionic liquid based enzyme-assisted extraction (ILEAE) of chlorogenic acid (CGA) from Eucommia ulmoides is presented in which enzyme pretreatment was used in ionic liquids aqueous media to enhance extraction yield. For this purpose, the solubility of CGA and the activity of cellulase were investigated in eight 1-alkyl-3-methylimidazolium ionic liquids. Cellulase in 0.5 M [C6mim]Br aqueous solution was found to provide better performance in extraction. The factors of ILEAE procedures including extraction time, extraction phase pH, extraction temperatures and enzyme concentrations were investigated. Moreover, the novel developed approach offered advantages in term of yield and efficiency compared with other conventional extraction techniques. Scanning electronic microscopy of plant samples indicated that cellulase treated cell wall in ionic liquid solution was subjected to extract, which led to more efficient extraction by reducing mass transfer barrier. The proposed ILEAE method would develope a continuous process for enzyme-assisted extraction including enzyme incubation and solvent extraction process. In this research, we propose a novel view for enzyme-assisted extraction of plant active component, besides concentrating on enzyme facilitated cell wall degradation, focusing on improvement of bad permeability of ionic liquids solutions. - Highlights: • An ionic liquid based enzyme-assisted extraction method of natural product was explored. • ILEAE utilizes enzymatic treatment to improve permeability of ionic liquids solution. • Enzyme incubation and solvent extraction process were ongoing simultaneously. • ILEAE process simplified operating process and suitable for more complete extraction.

  12. Application of ionic liquids based enzyme-assisted extraction of chlorogenic acid from Eucommia ulmoides leaves

    International Nuclear Information System (INIS)

    Liu, Tingting; Sui, Xiaoyu; Li, Li; Zhang, Jie; Liang, Xin; Li, Wenjing; Zhang, Honglian; Fu, Shuang

    2016-01-01

    A new approach for ionic liquid based enzyme-assisted extraction (ILEAE) of chlorogenic acid (CGA) from Eucommia ulmoides is presented in which enzyme pretreatment was used in ionic liquids aqueous media to enhance extraction yield. For this purpose, the solubility of CGA and the activity of cellulase were investigated in eight 1-alkyl-3-methylimidazolium ionic liquids. Cellulase in 0.5 M [C6mim]Br aqueous solution was found to provide better performance in extraction. The factors of ILEAE procedures including extraction time, extraction phase pH, extraction temperatures and enzyme concentrations were investigated. Moreover, the novel developed approach offered advantages in term of yield and efficiency compared with other conventional extraction techniques. Scanning electronic microscopy of plant samples indicated that cellulase treated cell wall in ionic liquid solution was subjected to extract, which led to more efficient extraction by reducing mass transfer barrier. The proposed ILEAE method would develope a continuous process for enzyme-assisted extraction including enzyme incubation and solvent extraction process. In this research, we propose a novel view for enzyme-assisted extraction of plant active component, besides concentrating on enzyme facilitated cell wall degradation, focusing on improvement of bad permeability of ionic liquids solutions. - Highlights: • An ionic liquid based enzyme-assisted extraction method of natural product was explored. • ILEAE utilizes enzymatic treatment to improve permeability of ionic liquids solution. • Enzyme incubation and solvent extraction process were ongoing simultaneously. • ILEAE process simplified operating process and suitable for more complete extraction.

  13. Ionic liquid-based microwave-assisted extraction of rutin from Chinese medicinal plants.

    Science.gov (United States)

    Zeng, Huan; Wang, Yuzhi; Kong, Jinhuan; Nie, Chan; Yuan, Ya

    2010-12-15

    An ionic liquid-based microwave-assisted extraction (ILMAE) method has been developed for the effective extraction of rutin from Chinese medicinal plants including Saururus chinensis (Lour.) Bail. (S. chinensis) and Flos Sophorae. A series of 1-butyl-3-methylimidazolium ionic liquids with different anions were investigated. The results indicated that the characteristics of anions have remarkable effects on the extraction efficiency of rutin and among the investigated ionic liquids, 1-butyl-3-methylimidazolium bromide ([bmim]Br) aqueous solution was the best. In addition, the ILMAE procedures for the two kinds of medicinal herbs were also optimized by means of a series of single factor experiments and an L(9) (3(4)) orthogonal design. Compared with the optimal ionic liquid-based heating extraction (ILHE), marinated extraction (ILME), ultrasonic-assisted extraction (ILUAE), the optimized approach of ILMAE gained higher extraction efficiency which is 4.879 mg/g in S. chinensis with RSD 1.33% and 171.82 mg/g in Flos Sophorae with RSD 1.47% within the shortest extraction time. Reversed phase high performance liquid chromatography (RP-HPLC) with ultraviolet detection was employed for the analysis of rutin in Chinese medicinal plants. Under the optimum conditions, the average recoveries of rutin from S. chinensis and Flos Sophorae were 101.23% and 99.62% with RSD lower than 3%, respectively. The developed approach is linear at concentrations from 42 to 252 mg L(-1) of rutin solution, with the regression coefficient (r) at 0.99917. Moreover, the extraction mechanism of ILMAE and the microstructures and chemical structures of the two researched samples before and after extraction were also investigated. With the help of LC-MS, it was future demonstrated that the two researched herbs do contain active ingredient of rutin and ionic liquids would not influence the structure of rutin. Copyright © 2010 Elsevier B.V. All rights reserved.

  14. Ionic liquids-lithium salts pretreatment followed by ultrasound-assisted extraction of vitexin-4″-O-glucoside, vitexin-2″-O-rhamnoside and vitexin from Phyllostachys edulis leaves.

    Science.gov (United States)

    Hou, Kexin; Chen, Fengli; Zu, Yuangang; Yang, Lei

    2016-01-29

    An efficient method for the extraction of vitexin, vitexin-4″-O-glucoside, and vitexin-2″-O-rhamnoside from Phyllostachys edulis leaves comprises heat treatment using an ionic liquid-lithium salt mixture (using 1-butyl-3-methylimidazolium bromide as the solvent and lithium chloride as the additive), followed by ultrasound-assisted extraction. To obtain higher extraction yields, the effects of the relevant experimental parameters (including heat treatment temperature and time, relative amounts of 1-butyl-3-methylimidazolium bromide and lithium chloride, power and time of the ultrasound irradiation, and the liquid-solid ratio) are evaluated and response surface methodology is used to optimize the significant factors. The morphologies of the treated and untreated P. edulis leaves are studied by scanning electron microscopy. The improved extraction method proposed provides high extraction yield, good repeatability and precision, and has wide potential applications in the analysis of plant samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. An efficient ultrasound assisted approach for the impregnation of room temperature ionic liquid onto Dowex 1 × 8 resin matrix and its application toward the enhanced adsorption of chromium (VI)

    International Nuclear Information System (INIS)

    Kalidhasan, S.; Santhana Krishna Kumar, A.; Vidya Rajesh; Rajesh, N.

    2012-01-01

    Highlights: ► Ultrasound assisted impregnation of an ionic liquid in a Dowex resin matrix is studied through various physicochemical and spectroscopic techniques. ► Chromium is adsorbed with a high adsorption capacity of 230.9 mg g −1 . ► The adsorbent is regenerated using HCl–ascorbic acid mixture. ► Chromium could be effectively detoxified from an industrial effluent and the developed method was validated with the analysis of a certified reference material. - Abstract: The work discussed in this paper is based on the utilization of ultrasound in conjunction with an ionic liquid (Aliquat 336) impregnated Dowex 1 × 8 resin for the effective adsorption of chromium. Ionic liquids are known for their selectivity toward metal extraction and ultrasonic medium offers efficient energy transfer for impregnating the ionic liquid in the resin matrix. The molecular interaction between the ionic liquid impregnated resin and chromium was studied through various physicochemical and spectroscopic techniques. The influence of various analytical parameters on the adsorption of Cr(VI) such as pH, adsorbent dosage, temperature and interference of foreign ions was studied in detail. Chromium (VI) was quantitatively adsorbed in the pH range of 3.5–4, with a high adsorption capacity of 230.9 mg g −1 in conformity with the Langmuir isotherm model. The study of thermodynamic parameters showed that the adsorption process is exothermic and spontaneous. The adsorbent could be regenerated using 1 mol L −1 HCl–0.28 mol L −1 ascorbic acid mixture. Chromium could be effectively detoxified from an industrial effluent and finally the developed method was validated with the analysis of a certified reference material (BCR-715). The obtained results indicated that the ultrasonic assisted impregnation of the room temperature ionic liquid significantly enhances and improves the removal efficiency of Cr(VI).

  16. Ionic liquids based simultaneous ultrasonic and microwave assisted extraction of phenolic compounds from burdock leaves

    International Nuclear Information System (INIS)

    Lou Zaixiang; Wang Hongxin; Zhu Song; Chen Shangwei; Zhang Ming; Wang Zhouping

    2012-01-01

    The ionic liquids based simultaneous ultrasonic and microwave assisted extraction (IL-UMAE) technique was first proposed and applied to isolate compounds. The ionic liquids comprising a range of four anions, five 1-alkyl-3-methylimidazolium derivatives were designed and prepared. The results suggested that varying the anion and cation both had apparent effects on the extraction of phenolics. The results also showed that irradiation power, time and solid–liquid ratio significantly affected the yields. The yields of caffeic acid and quercetin obtained by IL-UMAE were higher than those by regular UMAE. Compared with conventional heat-reflux extraction (HRE), the proposed approach exhibited higher efficiency (8–17% enhanced) and shorter extraction time (from 5 h to 30 s). The results indicated ILUMAE to be a fast and efficient extraction technique. Moreover, the proposed method was validated by the reproducibility and recovery experiments. The ILUMAE method provided good recoveries (from 96.1% to 105.3%) with RSD lower than 5.2%, which indicated that the proposed method was credible. Based on the designable nature of ionic liquids, and the rapid and highly efficient performance of the proposed approach, ILUMAE provided a new alternative for preparation of various useful substances from solid samples.

  17. Determination of heat capacity of ionic liquid based nanofluids using group method of data handling technique

    Science.gov (United States)

    Sadi, Maryam

    2018-01-01

    In this study a group method of data handling model has been successfully developed to predict heat capacity of ionic liquid based nanofluids by considering reduced temperature, acentric factor and molecular weight of ionic liquids, and nanoparticle concentration as input parameters. In order to accomplish modeling, 528 experimental data points extracted from the literature have been divided into training and testing subsets. The training set has been used to predict model coefficients and the testing set has been applied for model validation. The ability and accuracy of developed model, has been evaluated by comparison of model predictions with experimental values using different statistical parameters such as coefficient of determination, mean square error and mean absolute percentage error. The mean absolute percentage error of developed model for training and testing sets are 1.38% and 1.66%, respectively, which indicate excellent agreement between model predictions and experimental data. Also, the results estimated by the developed GMDH model exhibit a higher accuracy when compared to the available theoretical correlations.

  18. Advances in the electrodeposition of aluminum from ionic liquid based electrolytes

    Science.gov (United States)

    Leadbetter, Kirt C.

    Aluminum plating is of considerable technical and economic interest because it provides an eco-friendly substitute for cadmium coatings used on many military systems. However, cadmium has been determined to be a significant environmental safety and occupational health (ESOH) hazard because of its toxicity and carcinogenic nature. Furthermore, the cost of treating and disposing of generated wastes, which often contain cyanide, is costly and is becoming prohibitive in the face of increasingly stringent regulatory standards. The non-toxic alternative aluminum is equivalent or superior in performance to cadmium. In addition, it could serve to provide an alternative to hexavalent chromium coatings used on military systems for similar reasons to that of cadmium. Aluminum is a beneficial alternative in that it demonstrates self-healing corrosion resistance in the form of a tightly-bound, impervious oxide layer. A successfully plated layer would be serviceable over a wider temperature range, 925 °F for aluminum compared to 450 oF for cadmium. In addition, an aluminum layer can be anodized to make it non-conducting and colorable. In consideration of the plating process, aluminum cannot be deposited from aqueous solutions because of its reduction potential. Therefore, nonaqueous electrolytes are required for deposition. Currently, aluminum can be electrodeposited in nonaqueous processes that use hazardous chemicals such as toluene and pyrophoric aluminum alkyls. Electrodeposition from ionic liquids provides the potential for a safer method that could be easily scaled up for industrial application. The plating process could be performed at a lower temperature and higher current density than other commercially available aluminum electrodeposition processes; thus a reduced process cost could be possible. The current ionic liquid based electrolytes are more expensive; however production on a larger scale and a long electrolyte lifetime are associated with a reduction in price

  19. Self-Supporting, Hydrophobic, Ionic Liquid-Based Reference Electrodes Prepared by Polymerization-Induced Microphase Separation.

    Science.gov (United States)

    Chopade, Sujay A; Anderson, Evan L; Schmidt, Peter W; Lodge, Timothy P; Hillmyer, Marc A; Bühlmann, Philippe

    2017-10-27

    Interfaces of ionic liquids and aqueous solutions exhibit stable electrical potentials over a wide range of aqueous electrolyte concentrations. This makes ionic liquids suitable as bridge materials that separate in electroanalytical measurements the reference electrode from samples with low and/or unknown ionic strengths. However, methods for the preparation of ionic liquid-based reference electrodes have not been explored widely. We have designed a convenient and reliable synthesis of ionic liquid-based reference electrodes by polymerization-induced microphase separation. This technique allows for a facile, single-pot synthesis of ready-to-use reference electrodes that incorporate ion conducting nanochannels filled with either 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide or 1-dodecyl-3-methylimidazolium bis(trifluoromethyl sulfonyl)imide as ionic liquid, supported by a mechanically robust cross-linked polystyrene phase. This synthesis procedure allows for the straightforward design of various reference electrode geometries. These reference electrodes exhibit a low resistance as well as good reference potential stability and reproducibility when immersed into aqueous solutions varying from deionized, purified water to 100 mM KCl, while requiring no correction for liquid junction potentials.

  20. Ionic liquid ultrasound-assisted dispersive liquid-liquid microextraction based on solidification of the aqueous phase for preconcentration of heavy metals ions prior to determination by LC-UV.

    Science.gov (United States)

    Werner, Justyna

    2018-05-15

    Ionic liquid ultrasound-assisted dispersive liquid-liquid microextraction based on solidification of the aqueous phase was used for preconcentration of Ni 2+ , Co 2+ , Cd 2+ , Cu 2+ , Pb 2+ in natural water samples prior to liquid chromatography with UV detection. In the proposed method, the ammonium pyrrolidinedithiocarbamate was used as a complexing agent and the phosphonium ionic liquid trihexyl(tetradecyl)phosphonium bis[(2,4,4-trimethyl)pentyl]phosphinate (Cyphos IL 104) was used as an extractant. Ultrasound energy was used to disperse the extractant in the aqueous phase. After microextraction, the ionic liquid and aqueous phases were separated by centrifugation. Then the aqueous phase was frozen and the lighter than water ionic liquid phase containing metal ions complexes with pyrrolidinedithiocarbamate was separated and dissolved in a small volume of methanol prior to injection into the liquid chromatograph. Several parameters including the volume of extractant, the pH of the sample, the concentration of complexing agent, the time of ultrasound energy treatment, the time and speed of centrifugation and the effect of ionic strength were optimized. Under the optimized conditions (10 µL of Cyphos IL 104, pH = 5, 0.3% w/v ammonium pyrrolidinedithiocarbamate, 60 s of ultrasound use, 5 min/5000 rpm (2516×g) of centrifugation, 2.0 mg of NaCl), preconcentration factors were 211, 210, 209, 207 and 211 for Ni 2+ , Co 2+ , Cd 2+ , Cu 2+ and Pb 2+ respectively. Linearity was observed in the ranges 0.2-75.0 µg L -1 for Pb 2+ , Cd 2+ , Co 2+ and 0.5-100.0 µg L -1 for Cu 2+ , Ni 2+ . The limits of detection were 0.03 µg L -1 for Ni 2+ , 0.03 µg L -1 for Co 2+ , 0.03 µg L -1 for Cd 2+ , 0.02 µg L -1 for Cu 2+ , 0.02 µg L -1 for Pb 2+ , respectively. The accuracy of this method was evaluated by preconcentration and determination of Ni 2+ , Co 2+ , Cd 2+ , Cu 2+ , Pb 2+ in certified reference materials (TMRAIN-04 and NIST 1643e

  1. Cycling Performance of Li4Ti5O12 Electrodes in Ionic Liquid-Based Gel Polymer Electrolytes

    International Nuclear Information System (INIS)

    Kim, Jin Hee; Kim, Dong Won; Kang, Yong Ku

    2012-01-01

    We investigated the cycling behavior of Li 4 Ti 5 O 12 electrode in a cross-linked gel polymer electrolyte based on non-flammable ionic liquid consisting of 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl) imide and vinylene carbonate. The Li 4 Ti 5 O 12 electrodes in ionic liquid-based gel polymer electrolytes exhibited reversible cycling behavior with good capacity retention. Cycling data and electrochemical impedance spectroscopy analyses revealed that the optimum content of the cross-linking agent necessary to ensure both acceptable initial discharge capacity and good capacity retention was about 8 wt %

  2. Ultrasound-assisted synthesis of 2,4-thiazolidinedione and rhodanine derivatives catalyzed by task-specific ionic liquid: [TMG][Lac].

    Science.gov (United States)

    Suresh; Sandhu, Jagir Singh

    2013-03-03

    Synthesized arylidene derivatives of rhodanine and 2,4-thiazolidiendione have potent pharmacological activities, and these are also key substrates for the preparation of clinically used antidiabetics. Some 1,1,3,3-tetramethylguanidine-based task-specific ionic liquids (TSILs) 1a-1e were prepared and employed to the catalyzed solvent-free Knoevenagel condensation of 2,4-thiazolidinedione 3a and rhodanine 3b with a variety of aldehydes. Best results were obtained with 1,1,3,3-tetramethylguanidine lactate ([TMG][Lac]) 1c. The TSIL used can be easily recovered and recycled, yielding products 4-5 in excellent yields under ultrasonic environment without the formation of any side products or toxic waste.

  3. An efficient binary ionic liquid based quasi solid-state electrolyte for dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Chen, Junnian; Peng, Tianyou; Shi, Wenye; Li, Renjie; Xia, Jiangbin

    2013-01-01

    A novel binary ionic liquid electrolyte containing lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) and binary ionic liquids, which is composed of 1-butyl-3-methylimidazolium iodide (BMII) and 1-butyl-3-methylimidazolium thiocyanate (BMISCN), is developed for dye-sensitized solar cells (DSSCs). It is found that incorporation of LiTFSI as charge transfer promoter with BMII has positive effect on the interfacial charge transfer of the dye/TiO 2 film, further addition of BMISCN into the above composite electrolyte can take advantage of its low viscosity to enhance the ionic conductivity and reduce the interfacial charge transfer resistance, and a photovoltaic conversion efficiency of 5.55% is obtained from the solar cell fabricated with the optimized binary ionic liquid electrolyte without iodine participation under AM 1.5 illumination at 100 mW cm −2 , with a 108.6% improvement in the efficiency with lower resistance and higher ionic conductivity as compared to the solar cell fabricated with single BMII ionic liquid-based electrolyte. The above results should be attributed to the reduced charge recombination and the effective interfacial charge transfer in the solar cell

  4. Identification of degradation products of ionic liquids in an ultrasound assisted zero-valent iron activated carbon micro-electrolysis system and their degradation mechanism.

    Science.gov (United States)

    Zhou, Haimei; Lv, Ping; Shen, Yuanyuan; Wang, Jianji; Fan, Jing

    2013-06-15

    Ionic liquids (ILs) have potential applications in many areas of chemical industry because of their unique properties. However, it has been shown that the ILs commonly used to date are toxic and not biodegradable in nature, thus development of efficient chemical methods for the degradation of ILs is imperative. In this work, degradation of imidazolium, piperidinium, pyrrolidinium and morpholinium based ILs in an ultrasound and zero-valent iron activated carbon (ZVI/AC) micro-electrolysis system was investigated, and some intermediates generated during the degradation were identified. It was found that more than 90% of 1-alkyl-3-methylimidazolium bromide ([Cnmim]Br, n = 2, 4, 6, 8, 10) could be degraded within 110 min, and three intermediates 1-alkyl-3-methyl-2,4,5-trioxoimidazolidine, 1-alkyl-3-methylurea and N-alkylformamide were detected. On the other hand, 1-butyl-1-methylpiperidinium bromide ([C4mpip]Br), 1-butyl-1-methylpyrrolidinium bromide ([C4mpyr]Br) and N-butyl-N-methylmorpholinium bromide ([C4mmor]Br) were also effectively degraded through the sequential oxidization into hydroxyl, carbonyl and carboxyl groups in different positions of the butyl side chain, and then the N-butyl side chain was broken to form the final products of N-methylpiperidinium, N-methylpyrrolidinium and N-methylmorpholinium, respectively. Based on these intermediate products, degradation pathways of these ILs were suggested. These findings may provide fundamental information on the assessment of the factors related to the environmental fate and environmental behavior of these commonly used ILs. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Extraction of acetanilides in rice using ionic liquid-based matrix solid phase dispersion-solvent flotation.

    Science.gov (United States)

    Zhang, Liyuan; Wang, Changyuan; Li, Zuotong; Zhao, Changjiang; Zhang, Hanqi; Zhang, Dongjie

    2018-04-15

    Ionic liquid-based matrix solid phase dispersion-solvent flotation coupled with high performance liquid chromatography was developed for the determination of the acetanilide herbicides, including metazachlor, propanil, alachlor, propisochlor, pretilachlor, and butachlor in rice samples. Some experimental parameters, including the type of dispersant, the mass ratio of dispersant to sample, pH of sample solution, the type of extraction solvent, the type of ionic liquid, flotation time, and flow rate of N 2 were optimized. The average recoveries of the acetanilide herbicides at spiked concentrations of 50, 125, and 250 µg/kg ranged from 89.4% to 108.7%, and relative standard deviations were equal to or lower than 7.1%, the limits of quantification were in the range of 38.0 to 84.7 µg/kg. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Determination of phenolic acids and flavonoids in raw propolis by silica-supported ionic liquid-based matrix solid phase dispersion extraction high performance liquid chromatography-diode array detection.

    Science.gov (United States)

    Wang, Zhibing; Sun, Rui; Wang, Yuanpeng; Li, Na; Lei, Lei; Yang, Xiao; Yu, Aimin; Qiu, Fangping; Zhang, Hanqi

    2014-10-15

    The silica-supported ionic liquid (S-SIL) was prepared by impregnation and used as the dispersion adsorbent of matrix solid phase dispersion (MSPD) for the simultaneous extraction of eight phenolic acids and flavonoids, including caffeic acid, ferulic acid, morin, luteolin, quercetin, apigenin, chrysin, and kaempferide in raw propolis. High performance liquid chromatography with a Zorbax SB-C18 column (150mm×4.6mm, 3.5μm) was used for separation of the analytes. The mobile phase consisted of 0.2% phosphoric acid aqueous solution and acetonitrile and the flow rate of the mobile phase was 0.5mL/min. The experimental conditions for silica-supported ionic liquid-based matrix solid phase dispersion (S-SIL-based MSPD) were optimized. S-SIL containing 10% [C6MIM]Cl was used as dispersant, 20mL of n-hexane as washing solvent and 15mL of methanol as elution solvent. The ratio of S-SIL to sample was selected to be 4:1. The standard curves showed good linear relationship (r>0.9995). The limits of detection and quantification were in the range of 5.8-22.2ngmL(-1) and 19.2-74.0ngmL(-1), respectively. The relative standard deviations (RSDs) of intra-day and inter-day determination were lower than 8.80% and 11.19%, respectively. The recoveries were between 65.51% and 92.32% with RSDs lower than 8.95%. Compared with ultrasound-assisted extraction (UAE) and soxhlet extraction, the present method consumed less sample, organic solvent, and extraction time, although the extraction yields obtained by S-SIL-based MSPD are slightly lower than those obtained by UAE. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Toxicity prediction of ionic liquids based on Daphnia magna by using density functional theory

    Science.gov (United States)

    Nu’aim, M. N.; Bustam, M. A.

    2018-04-01

    By using a model called density functional theory, the toxicity of ionic liquids can be predicted and forecast. It is a theory that allowing the researcher to have a substantial tool for computation of the quantum state of atoms, molecules and solids, and molecular dynamics which also known as computer simulation method. It can be done by using structural feature based quantum chemical reactivity descriptor. The identification of ionic liquids and its Log[EC50] data are from literature data that available in Ismail Hossain thesis entitled “Synthesis, Characterization and Quantitative Structure Toxicity Relationship of Imidazolium, Pyridinium and Ammonium Based Ionic Liquids”. Each cation and anion of the ionic liquids were optimized and calculated. The geometry optimization and calculation from the software, produce the value of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). From the value of HOMO and LUMO, the value for other toxicity descriptors were obtained according to their formulas. The toxicity descriptor that involves are electrophilicity index, HOMO, LUMO, energy gap, chemical potential, hardness and electronegativity. The interrelation between the descriptors are being determined by using a multiple linear regression (MLR). From this MLR, all descriptors being analyzed and the descriptors that are significant were chosen. In order to develop the finest model equation for toxicity prediction of ionic liquids, the selected descriptors that are significant were used. The validation of model equation was performed with the Log[EC50] data from the literature and the final model equation was developed. A bigger range of ionic liquids which nearly 108 of ionic liquids can be predicted from this model equation.

  8. Solvation of ionic liquids based on N-methyl-N-alkyl morpholinium cations in dimethylsulfoxide – volumetric and compressibility studies

    International Nuclear Information System (INIS)

    Marcinkowski, Łukasz; Kloskowski, Adam; Czub, Jacek; Namieśnik, Jacek; Warmińska, Dorota

    2015-01-01

    Highlights: • In DMSO both volumes and compressibilities of ionic liquids were studied. • Molecular dynamics simulations were performed for all studied ionic liquids. • V Φ of DMSO solutions of [Mor 1,R ][TFSI] decrease with increasing IL concentration. • Results indicate that [Mor 1,R ][TFSI] are structure breakers in dimethylsulfoxide. • Obtained results are the consequence of the cation size of the ionic liquid. - Abstract: The density and sound velocity of the solutions of ionic liquids based on N-alkyl-N-methyl-morpholinium cations, N-ethyl-N-methylmorpholinium bis(trifluoromethanesulfonyl)imide, N-butyl-N-methylmorpholinium bis(trifluoromethanesulfonyl)imide, N-methyl-N-octyl-morpholinium bis(trifluoromethanesulfonyl)imide and N-decyl-N-methylmorpholinium bis(trifluoromethanesulfonyl)imide in dimethylsulfoxide were measured at T = (298.15 to 318.15) K and at atmospheric pressure. The apparent molar volume and apparent molar compressibility values were evaluated from density and sound velocity values and fitted to the Masson equation from which the partial molar volume and partial molar isentropic compressibility of the ILs at infinite dilution were also calculated at working temperatures. By using the density values, the limiting apparent molar expansibilities were estimated. The effect of the alkyl chain length of the ILs and experimental temperature on these thermodynamic properties is discussed. In addition, molecular dynamics simulations were used to interpret the measured properties in terms of interactions of ILs with solvent molecules. Both, volumetric measurements results and molecular dynamics simulations for ionic liquids in dimethylsulfoxide were compared and discussed with results obtained for the same IL in acetonitrile

  9. All-solid-state flexible supercapacitors based on papers coated with carbon nanotubes and ionic-liquid-based gel electrolytes

    International Nuclear Information System (INIS)

    Kang, Yu Jin; Kim, Woong; Chung, Haegeun; Han, Chi-Hwan

    2012-01-01

    All-solid-state flexible supercapacitors were fabricated using carbon nanotubes (CNTs), regular office papers, and ionic-liquid-based gel electrolytes. Flexible electrodes were made by coating CNTs on office papers by a drop-dry method. The gel electrolyte was prepared by mixing fumed silica nanopowders with ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][NTf 2 ]). This supercapacitor showed high power and energy performance as a solid-state flexible supercapacitor. The specific capacitance of the CNT electrodes was 135 F g −1 at a current density of 2 A g −1 , when considering the mass of active materials only. The maximum power and energy density of the supercapacitors were 164 kW kg −1 and 41 Wh kg −1 , respectively. Interestingly, the solid-state supercapacitor with the gel electrolyte showed comparable performance to the supercapacitors with ionic-liquid electrolyte. Moreover, the supercapacitor showed excellent stability and flexibility. The CNT/paper- and gel-based supercapacitors may hold great potential for low-cost and high-performance flexible energy storage applications. (paper)

  10. Factors affecting the stability and performance of ionic liquid-based planar transient photodetectors.

    Science.gov (United States)

    Dalgleish, Simon; Reissig, Louisa; Hu, Laigui; Matsushita, Michio M; Sudo, Yuki; Awaga, Kunio

    2015-05-12

    A novel planar architecture has been developed for the study of photodetectors utilizing the transient photocurrent response induced by a metal/insulator/semiconductor/metal (MISM) structured device, where the insulator is an ionic liquid (IL-MISM). Using vanadyl 2,3-naphthalocyanine, which absorbs in the communications-relevant near-infrared wavelength region (λ(max,film) ≈ 850 nm), in conjunction with C60 as a bulk heterojunction, the high capacitance of the formed electric double layers at the ionic liquid interfaces yields high charge separation efficiency within the semiconductor layer, and the minimal potential drop in the bulk ionic liquid allows the electrodes to be offset by distances of over 7 mm. Furthermore, the decrease in operational speed with increased electrode separation is beneficial for a clear modeling of the waveform of the photocurrent signal, free from the influence of measurement circuitry. Despite the use of a molecular semiconductor as the active layer in conjunction with a liquid insulating layer, devices with a stability of several days could be achieved, and the operational stability of such devices was shown to be dependent solely on the solubility of the active layer in the ionic liquid, even under atmospheric conditions. Furthermore, the greatly simplified device construction process, which does not rely on transparent electrode materials or direct electrode deposition, provides a highly reproducible platform for the study of the electronic processes within IL-MISM detectors that is largely free from architectural constraints.

  11. Mesoporous Carbon Design for Ionic Liquid-Based, Double-Layer Supercapacitors

    OpenAIRE

    2010-01-01

    Abstract The use of pyrrolidinium-based ionic liquids (ILs) in asymmetric electric double-layer capacitors (AEDLC) with positive and negative carbon electrodes of different weight is a powerful strategy for developing safe, high specific-energy supercapacitors operating at > 3.5 V. The preparation and characterization of ordered (OTC) and disordered (DTC) template carbons, the latter obtained by a fast and low-cost method, are reported. The porosity and capacitance features of the ...

  12. Hydrophobic ionic liquids based on the 1-butyl-3-methylimidazolium cation for lithium/seawater batteries

    Science.gov (United States)

    Zhang, Yancheng; Urquidi-Macdonald, Mirna

    Two hydrophobic ionic liquids (room temperature molten salts) based on 1-butyl-3-methylimidazolium cation (BMI +), BMI +PF 6- and BMI +Tf 2N -, were used in developing a highly efficient lithium anode system for lithium/seawater batteries. The lithium anode system was composed of lithium metal/ionic liquid/Celgard membrane. Both BMI +PF 6-and BMI +Tf 2N - maintained high apparent anodic efficiency (up to 100%) under potentiostatic polarization (at +0.5 V versus open-circuit potential (OCP)) in a 3% NaCl solution. Eventually, traces of water contaminated the ionic liquid and a bilayer film (LiH and LiOH) on the lithium surface was formed, decreasing the rate of lithium anodic reaction and hence the discharge current density. BMI +Tf 2N - prevented traces of water from reaching the lithium metal surface longer than BMI +PF 6- (60 h versus 7 h). However, BMI +PF 6- was better than BMI +Tf 2N - in keeping a constant current density (˜0.2 mA cm -2) before the traces of water contaminated the lithium surface due to the non-reactivity of BMI +PF 6- with the lithium metal that kept the bare lithium surface. During the discharge process, BMI +PF 6- and BMI +Tf 2N - acted as ion transport media of Li +, Cl -, OH - and H 2O, but did not react with them because of the excellent chemical stability, high conductivity, and high hydrophobicity of these two ionic liquids. Both BMI +PF 6- and BMI +Tf 2N - gels were tentative approaches used to delay the traces of water coming in contact with the lithium surface.

  13. Polymeric ionic liquid based on magnetic materials fabricated through layer-by-layer assembly as adsorbents for extraction of pesticides.

    Science.gov (United States)

    He, Lijun; Cui, Wenhang; Wang, Yali; Zhao, Wenjie; Xiang, Guoqiang; Jiang, Xiuming; Mao, Pu; He, Juan; Zhang, Shusheng

    2017-11-03

    In this study, layer-by-layer assembly of polyelectrolyte multilayer films on magnetic silica provided a convenient and controllable way to prepare polymeric ionic liquid-based magnetic adsorbents. The resulting particles were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, and magnetic measurements. The data showed that the magnetic particles had more homogeneous spherical shapes with higher saturation magnetization when compared to those obtained by free radical polymerization method. This facilitated the convenient collection of magnetic particles, with higher extraction repeatability. The extraction performance of the multilayer polymeric ionic liquid-based adsorbents was evaluated by magnetic solid-phase extraction of four pesticides including quinalphos, fenthion, phoxim, and chlorpropham. The data suggested that the extraction efficiency depended on the number of layers in the film. The parameters affecting the extraction efficiency were optimized, and good linearity ranging from 2 to 250μgL -1 was obtained with correlation coefficients of 0.9994-0.9998. Moreover, the proposed method presented low limit of detection (0.5μgL -1 , S/N=3) and limit of quantification (1.5μgL -1 , S/N=10), and good repeatability expressed by the relative standard deviation (2.0%-4.6%, n=5). The extraction recoveries of four pesticides were found to range from 58.9% to 85.8%. The reliability of the proposed method was demonstrated by analyzing environmental water samples, and the results revealed satisfactory spiked recovery, relative standard deviation, and selectivity. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Fabrication of an ionic-liquid-based polymer monolithic column and its application in the fractionation of proteins from complex biosamples.

    Science.gov (United States)

    Zhang, Doudou; Zhang, Qian; Bai, Ligai; Han, Dandan; Liu, Haiyan; Yan, Hongyuan

    2018-05-01

    An ionic-liquid-based polymer monolithic column was synthesized by free radical polymerization within the confines of a stainless-steel column (50 mm × 4.6 mm id). In the processes, ionic liquid and stearyl methacrylate were used as dual monomers, ethylene glycol dimethacrylate as the cross-linking agent, and polyethylene glycol 200 and isopropanol as co-porogens. Effects of the prepolymerization solution components on the properties of the resulting monoliths were studied in detail. Scanning electron microscopy, nitrogen adsorption-desorption measurements, and mercury intrusion porosimetry were used to investigate the morphology and pore size distribution of the prepared monoliths, which showed that the homemade ionic-liquid-based monolith column possessed a relatively uniform macropore structure with a total macropore specific surface area of 44.72 m 2 /g. Compared to a non-ionic-liquid-based monolith prepared under the same conditions, the ionic-liquid-based monolith exhibited excellent selectivity and high performance for separating proteins from complex biosamples, such as egg white, snailase, bovine serum albumin digest solution, human plasma, etc., indicating promising applications in the fractionation and analysis of proteins from the complex biosamples in proteomics research. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Instability of Ionic Liquid-Based Electrolytes in Li−O2 Batteries

    DEFF Research Database (Denmark)

    Das, Supti; Højberg, Jonathan; Knudsen, Kristian Bastholm

    2015-01-01

    Ionic liquids (ILs) have been proposed as promising solvents for Li−air battery electrolytes. Here, several ILs have been investigated using differential electrochemical mass spectrometry (DEMS) to investigate the electrochemical stability in a Li−O2 system, by means of quantitative determination...... of the rechargeability (OER/ORR), and thereby the Coulombic efficiency of discharge and charge. None of the IL-based electrolytes are found to behave as needed for a functional Li−O2 battery but perform better than commonly used organic solvents. Also the extent of rechargeability/reversibility has been found...

  16. Systematic screening methodology and energy efficient design of ionic liquid-based separation processes

    DEFF Research Database (Denmark)

    Kulajanpeng, Kusuma; Suriyapraphadilok, Uthaiporn; Gani, Rafiqul

    2016-01-01

    in size of the target solute was investigated using the same separation process and IL entrainer to obtain the same product purity. The proposed methodology has been evaluated through a case study of binary alcoholic aqueous azeotropic separation: water+ethanol and water+isopropanol.......A systematic methodology for the screening of ionic liquids (ILs) as entrainers and for the design of ILs-based separation processes in various homogeneous binary azeotropic mixtures has been developed. The methodology focuses on the homogeneous binary aqueous azeotropic systems (for example, water...

  17. Phenyl and ionic liquid based bifunctional periodic mesoporous organosilica supported copper: An efficient nanocatalyst for clean production of polyhydroquinolines.

    Science.gov (United States)

    Elhamifar, Dawood; Ardeshirfard, Hakimeh

    2017-11-01

    A novel phenyl and ionic liquid based bifunctional periodic mesoporous organosilica supported copper (Cu@BPMO-Ph-IL) is prepared, characterized and its catalytic application is developed in the clean production of polyhydroquinolines. The Cu@BPMO-Ph-IL was prepared via chemical grafting of ionic liquid groups onto phenyl-based PMO followed by treatment with copper acetate. This nanocatalyst was characterized with transmission electron microscopy (TEM), scanning electron microscopy (SEM), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTs), thermal gravimetric analysis (TGA), powder X-ray diffraction (PXRD), nitrogen-sorption and energy dispersive X-ray (EDX) analyses. This was successfully applied in the one-pot Hantzsch condensation of aldehydes, ammonium acetate, alkylacetoacetates and dimedone to prepare a set of different derivatives of polyhydroquinolines in high yields and selectivity. The catalyst was effectively recovered and reused several times without important decrease in efficiency. The recovered catalyst was also characterized with TEM analysis to study its stability and durability under applied conditions. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Ionic liquid-based microwave-assisted extraction of essential oil and biphenyl cyclooctene lignans from Schisandra chinensis Baill fruits.

    Science.gov (United States)

    Ma, Chun-hui; Liu, Ting-ting; Yang, Lei; Zu, Yuan-gang; Chen, Xiaoqiang; Zhang, Lin; Zhang, Ying; Zhao, Chunjian

    2011-12-02

    Ionic liquid-based microwave-assisted extraction (ILMAE) has been successfully applied in extracting essential oil and four kinds of biphenyl cyclooctene lignans from Schisandra chinensis Baill. 0.25 M 1-lauryl-3-methylimidazolium bromide ionic liquid is selected as solvent. The optimum parameters of dealing with 25.0 g sample are 385 W irradiation power, 40 min microwave extraction time and 1:12 solid-liquid ratio. The yields of essential oil and lignans are 12.12±0.37 ml/kg and 250.2±38.2 mg/kg under the optimum conditions. The composition of the essential oil extracted by hydro-distillation, steam-distillation and ILMAE is analyzed by GC-MS. With ILMAE method, the energy consumption time has not only been shortened to 40 min (hydro-distillation 3.0 h for extracting essential oil and reflux extraction 4.0 h for extracting lignans, respectively), but also the extraction efficiency has been improved (extraction of lignans and distillation of essential oil at the same time) and reduces the environmental pollution. S. chinensis materials treated by different methods are observed by scanning electronic microscopy. Micrographs provide more evidence to prove that ILMAE is a better and faster method. The experimental results also indicate that ILMAE is a simple and efficient technique for sample preparation. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. Treatment of Mineral Oil Refinery Wastewater in Microbial Fuel Cells Using Ionic Liquid Based Separators

    Directory of Open Access Journals (Sweden)

    Hasna Addi

    2018-03-01

    Full Text Available Microbial fuel cells (MFCs are an environmentally friendly technology that can recover electricity directly from several wastes at ambient temperatures. This work explores the use of mineral oil refinery wastewater as feedstock in single-chamber air-cathode MFC devices. A polymer inclusion membrane based on the ionic liquid methyltrioctylammonium chloride, [MTOA+][Cl−], at a concentration of 70% w/w, was used as separator, showing a good efficiency in power production and chemical oxygen demand (COD removal. The power and the chemical oxygen demand removal reached values of 45 mW/m3 and over 80%, respectively. The evolution of other parameters of the wastewater including nitrites, phosphates and sulphates were also studied. Kjeldahl nitrogen and sulphates were significantly reduced during MFC operation. The results show that mineral oil refinery wastewater can be used as feedstock in air breathing cathode-microbial fuel cells based on polymer ionic liquid inclusion membranes. This configuration could represent a good alternative for wastewater depuration while producing energy during the process.

  20. Solid-state supercapacitors with ionic liquid based gel polymer electrolyte: Effect of lithium salt addition

    Science.gov (United States)

    Pandey, G. P.; Hashmi, S. A.

    2013-12-01

    Performance characteristics of the solid-state supercapacitors fabricated with ionic liquid (IL) incorporated gel polymer electrolyte and acid treated multiwalled carbon nanotube (MWCNT) electrodes have been studied. The effect of Li-salt (LiPF6) addition in the IL (1-ethyl-3-methylimidazolium tris(pentafluoroethyl) trifluorophosphate, EMImFAP) based gel electrolyte on the performance of supercapacitors has been specifically investigated. The LiPF6/IL/poly(vinylidine fluoride-co-hexafluoropropylene) (PVdF-HFP) gel electrolyte film possesses excellent electrochemical window of 4 V (from -2.0 to 2.0 V), high ionic conductivity ∼2.6 × 10-3 S cm-1 at 20 °C and high enough thermal stability. The comparative performance of supercapacitors employing electrolytes with and without lithium salt has been evaluated by impedance spectroscopy and cyclic voltammetric studies. The acid-treated MWCNT electrodes show specific capacitance of ∼127 F g-1 with IL/LiPF6 containing gel polymer electrolyte as compared to that with the gel polymer electrolyte without Li-salt, showing the value of ∼76 F g-1. The long cycling stability of the solid state supercapacitor based on the Li-salt containing gel polymer electrolyte confirms the electrochemical stability of the electrolyte.

  1. A New Green Ionic Liquid-Based Corrosion Inhibitor for Steel in Acidic Environments

    Directory of Open Access Journals (Sweden)

    Ayman M. Atta

    2015-06-01

    Full Text Available This work examines the use of new hydrophobic ionic liquid derivatives, namely octadecylammonium tosylate (ODA-TS and oleylammonium tosylate (OA-TS for corrosion protection of steel in 1 M hydrochloric acid solution. Their chemical structures were determined from NMR analyses. The surface activity characteristics of the prepared ODA-TS and OA-TS were evaluated from conductance, surface tension and contact angle measurements. The data indicate the presence of a double bond in the chemical structure of OA-TS modified its surface activity parameters. Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS measurements, scanning electron microscope (SEM, Energy dispersive X-rays (EDX analysis and contact angle measurements were utilized to investigate the corrosion protection performance of ODA-TS and OA-TS on steel in acidic solution. The OA-TS and ODA-TS compounds showed good protection performance in acidic chloride solution due to formation of an inhibitive film on the steel surface.

  2. Flexible, ionic liquid-based micro-supercapacitor produced by supersonic cluster beam deposition

    International Nuclear Information System (INIS)

    Bettini, L.G.; Piseri, P.; De Giorgio, F.; Arbizzani, C.; Milani, P.; Soavi, F.

    2015-01-01

    Highlights: • We exploited Supersonic Cluster Beam Deposition for the fabrication of a flexible, planar micro-supercapacitor featuring nanostructured carbon electrodes deposited on a plastic Mylar substrate and N-trimethyl-N-propyl-ammonium bis(trifluoromethanesulfonyl) imide (N 1113 TFSI) ionic liquid electrolyte. • The micro-supercapacitor operates at 3 V above RT up to 80 °C with a capacitance density approaching 10 F cm −3 and delivering maximum specific energy and power densities of 10 mWh cm −3 and 8-10 W cm −3 . • The micro-supercapacitor features long cycling stability over 2x10 4 cycle on flat and bent configuration. -- Graphical abstract: Display Omitted -- Abstract: Power generation and storage in electronics require flexible, thin micro-electrochemical energy storage/conversion systems. Micro-supercapacitors (μSCs) with double-layer capacitance carbon electrodes are attracting much attention for their capability of delivering short power pulses with high stability over repeated charge/discharge cycling. Supersonic Cluster Beam Deposition (SCBD) is an effective strategy for the development of nanostructured, binder-free porous carbon electrodes on temperature sensitive substrates including polymers. We exploited SCBD for the development of a flexible, planar μSC featuring nanostructured carbon (ns-C) electrodes deposited on a plastic Mylar substrate and N-trimethyl-N-propyl-ammonium bis(trifluoromethanesulfonyl) imide (N 1113 TFSI) ionic liquid electrolyte. The electrochemical performance at different temperatures of the μSC which operates at 3 V above RT up to 80 °C with a capacitance density approaching 10 F cm −3 and delivering maximum specific energy and power densities of 10 mWh cm −3 and 8-10 W cm −3 with long cycling stability over 2 × 10 4 cycles is here reported and discussed

  3. Pesticide extraction from table grapes and plums using ionic liquid based dispersive liquid-liquid microextraction.

    Science.gov (United States)

    Ravelo-Pérez, Lidia M; Hernández-Borges, Javier; Herrera-Herrera, Antonio V; Rodríguez-Delgado, Miguel Angel

    2009-12-01

    Room temperature ionic liquids (RTILs) have been used as extraction solvents in dispersive liquid-liquid microextraction (DLLME) for the determination of eight multi-class pesticides (i.e. thiophanate-methyl, carbofuran, carbaryl, tebuconazole, iprodione, oxyfluorfen, hexythiazox, and fenazaquin) in table grapes and plums. The developed method involves the combination of DLLME and high-performance liquid chromatography with diode array detection. Samples were first homogenized and extracted with acetonitrile. After evaporation and reconstitution of the extract in water containing sodium chloride, a quick DLLME procedure that used the ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate ([C(6)MIM][PF(6)]) and methanol was developed. The RTIL dissolved in a very small volume of acetonitrile was directed injected in the chromatographic system. The comparison between the calibration curves obtained from standards and from spiked sample extracts (matrix-matched calibration) showed the existence of a strong matrix effect for most of the analyzed pesticides. A recovery study was also developed with five consecutive extractions of the two types of fruits spiked at three concentration levels. Mean recovery values were in the range of 72-100% for table grapes and 66-105% for plum samples (except for thiophanate-methyl and carbofuran, which were 64-75% and 58-66%, respectively). Limits of detection (LODs) were in the range 0.651-5.44 microg/kg for table grapes and 0.902-6.33 microg/kg for plums, representing LODs below the maximum residue limits (MRLs) established by the European Union in these fruits. The potential of the method was demonstrated by analyzing 12 commercial fruit samples (six of each type).

  4. Ionic liquid based dispersive liquid-liquid microextraction for the extraction of pesticides from bananas.

    Science.gov (United States)

    Ravelo-Pérez, Lidia M; Hernández-Borges, Javier; Asensio-Ramos, María; Rodríguez-Delgado, Miguel Angel

    2009-10-23

    This paper describes a dispersive liquid-liquid microextraction (DLLME) procedure using room temperature ionic liquids (RTILs) coupled to high-performance liquid chromatography with diode array detection capable of quantifying trace amounts of eight pesticides (i.e. thiophanate-methyl, carbofuran, carbaryl, tebuconazole, iprodione, oxyfluorfen, hexythiazox and fenazaquin) in bananas. Fruit samples were first homogenized and extracted (1g) with acetonitrile and after suitable evaporation and reconstitution of the extract in 10 mL of water, a DLLME procedure using 1-hexyl-3-methylimidazolium hexafluorophosphate ([C(6)MIM][PF(6)]) as extraction solvent was used. Experimental conditions affecting the DLLME procedure (sample pH, sodium chloride percentage, ionic liquid amount and volume of disperser solvent) were optimized by means of an experimental design. In order to determine the presence of a matrix effect, calibration curves for standards and fortified banana extracts (matrix matched calibration) were studied. Mean recovery values of the extraction of the pesticides from banana samples were in the range of 69-97% (except for thiophanate-methyl and carbofuran, which were 53-63%) with a relative standard deviation lower than 8.7% in all cases. Limits of detection achieved (0.320-4.66 microg/kg) were below the harmonized maximum residue limits established by the European Union (EU). The proposed method, was also applied to the analysis of this group of pesticides in nine banana samples taken from the local markets of the Canary Islands (Spain). To the best of our knowledge, this is the first application of RTILs as extraction solvents for DLLME of pesticides from samples different than water.

  5. Ionic liquid-based microwave-assisted extraction of flavonoids from Bauhinia championii (Benth.) Benth.

    Science.gov (United States)

    Xu, Wei; Chu, Kedan; Li, Huang; Zhang, Yuqin; Zheng, Haiyin; Chen, Ruilan; Chen, Lidian

    2012-12-03

    An ionic liquids (IL)-based microwave-assisted approach for extraction and determination of flavonoids from Bauhinia championii (Benth.) Benth. was proposed for the first time. Several ILs with different cations and anions and the microwave-assisted extraction (MAE) conditions, including sample particle size, extraction time and liquid-solid ratio, were investigated. Two M 1-butyl-3-methylimidazolium bromide ([bmim] Br) solution with 0.80 M HCl was selected as the optimal solvent. Meanwhile the optimized conditions a ratio of liquid to material of 30:1, and the extraction for 10 min at 70 °C. Compared with conventional heat-reflux extraction (CHRE) and the regular MAE, IL-MAE exhibited a higher extraction yield and shorter extraction time (from 1.5 h to 10 min). The optimized extraction samples were analysed by LC-MS/MS. IL extracts of Bauhinia championii (Benth.)Benth consisted mainly of flavonoids, among which myricetin, quercetin and kaempferol, β-sitosterol, triacontane and hexacontane were identified. The study indicated that IL-MAE was an efficient and rapid method with simple sample preparation. LC-MS/MS was also used to determine the chemical composition of the ethyl acetate/MAE extract of Bauhinia championii (Benth.) Benth, and it maybe become a rapid method to determine the composition of new plant extracts.

  6. Pyridinium ionic liquid-based liquid-solid extraction of inorganic and organic iodine from Laminaria.

    Science.gov (United States)

    Peng, Li-Qing; Yu, Wen-Yan; Xu, Jing-Jing; Cao, Jun

    2018-01-15

    A simple, green and effective extraction method, namely, pyridinium ionic liquid- (IL) based liquid-solid extraction (LSE), was first designed to extract the main inorganic and organic iodine compounds (I - , monoiodo-tyrosine (MIT) and diiodo-tyrosine (DIT)). The optimal extraction conditions were as follows: ultrasonic intensity 100W, IL ([EPy]Br) concentration 200mM, extraction time 30min, liquid/solid ratio 10mL/g, and pH value 6.5. The morphologies of Laminaria were studied by scanning electron microscopy and transmission electron microscopy. The recovery values of I - , MIT and DIT from Laminaria were in the range of 88% to 94%, and limits of detection were in the range of 59.40 to 283.6ng/g. The proposed method was applied to the extraction and determination of iodine compounds in three Laminaria. The results showed that IL-based LSE could be a promising method for rapid extraction of bioactive iodine from complex food matrices. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Ionic-Liquid-Based CO2 Capture Systems: Structure, Interaction and Process.

    Science.gov (United States)

    Zeng, Shaojuan; Zhang, Xiangping; Bai, Lu; Zhang, Xiaochun; Wang, Hui; Wang, Jianji; Bao, Di; Li, Mengdie; Liu, Xinyan; Zhang, Suojiang

    2017-07-26

    The inherent structure tunability, good affinity with CO 2 , and nonvolatility of ionic liquids (ILs) drive their exploration and exploitation in CO 2 separation field, and has attracted remarkable interest from both industries and academia. The aim of this Review is to give a detailed overview on the recent advances on IL-based materials, including pure ILs, IL-based solvents, and IL-based membranes for CO 2 capture and separation from the viewpoint of molecule to engineering. The effects of anions, cations and functional groups on CO 2 solubility and selectivity of ILs, as well as the studies on degradability of ILs are reviewed, and the recent developments on functionalized ILs, IL-based solvents, and IL-based membranes are also discussed. CO 2 separation mechanism with IL-based solvents and IL-based membranes are explained by combining molecular simulation and experimental characterization. Taking into consideration of the applications and industrialization, the recent achievements and developments on the transport properties of IL fluids and the process design of IL-based processes are highlighted. Finally, the future research challenges and perspectives of the commercialization of CO 2 capture and separation with IL-based materials are posed.

  8. The Mechanism of Room-Temperature Ionic-Liquid-Based Electrochemical CO₂ Reduction: A Review.

    Science.gov (United States)

    Lim, Hyung-Kyu; Kim, Hyungjun

    2017-03-28

    Electrochemical CO₂ conversion technology is becoming indispensable in the development of a sustainable carbon-based economy. While various types of electrocatalytic systems have been designed, those based on room-temperature ionic liquids (RTILs) have attracted considerable attention because of their high efficiencies and selectivities. Furthermore, it should be possible to develop more advanced electrocatalytic systems for commercial use because target-specific characteristics can be fine-tuned using various combinations of RTIL ions. To achieve this goal, we require a systematic understanding of the role of the RTIL components in electrocatalytic systems, however, their role has not yet been clarified by experiment or theory. Thus, the purpose of this short review is to summarize recent experimental and theoretical mechanistic studies to provide insight into and to develop guidelines for the successful development of new CO₂ conversion systems. The results discussed here can be summarized as follows. Complex physical and chemical interactions between the RTIL components and the reaction intermediates, in particular at the electrode surface, are critical for determining the activity and selectivity of the electrocatalytic system, although no single factor dominates. Therefore, more fundamental research is required to understand the physical, chemical, and thermodynamic characteristics of complex RTIL-based electrocatalytic systems.

  9. Mesoporous carbon design for ionic liquid-based, double-layer supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Lazzari, M.; Soavi, F.; Mastragostino, M. [Dipartimento di Scienza dei Metalli, Elettrochimica e Tecniche Chimiche, University of Bologna (Italy)

    2010-10-15

    The use of pyrrolidinium-based ionic liquids (ILs) in asymmetric electric double-layer capacitors (AEDLC) with positive and negative carbon electrodes of different weight is a powerful strategy for developing safe, high specific-energy supercapacitors operating at >3.5 V. The preparation and characterisation of ordered (OTC) and disordered (DTC) template carbons, the latter obtained by a fast and low-cost method, are reported. The porosity and capacitance features of the template carbons are discussed in view of their application in IL-based AEDLCs and compared with the properties of aero/cryo/xerogel carbons and a commercial activated carbon. The performance of an N-butyl-N-methyl pyrrolidinium bis(trifluoromethanesulfonyl)imide-based AEDLC assembled with DTC carbon electrodes operating at 3.9 V featuring high specific energy of 47 Wh kg{sup -1} is then reported. The impact of porosity and surface chemistry of carbons on the electrode capacitive response in IL and on the performance of the IL-based AEDLC in terms of energy, power and weight distribution of module components is discussed. The effect of IL nature and carbon porosity on the time constant of the double-layer charging process was also investigated by voltammetric and impedance studies. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  10. Boosting the Performance of Ionic-Liquid-Based Supercapacitors with Polar Additives

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Kun [Univ. of California, Riverside, CA (United States). Dept. of Chemical and Environmental Engineering; Wu, Jianzhong [Univ. of California, Riverside, CA (United States). Dept. of Chemical and Environmental Engineering

    2016-10-05

    Recent years have witnessed growing interests in both the fundamentals and applications of electric double layer capacitors (EDLCs), also known as supercapacitors. A number of strategies have been explored to optimize the device performance in terms of both the energy and power densities. Because the properties of electric double layers (EDL) are sensitive to ion distributions in the close vicinity of the electrode surfaces, the supercapacitor performance is sensitive to both the electrode pore structure and the electrolyte composition. In this paper, we study the effects of polar additives on EDLC capacitance using the classical density functional theory within the framework of a coarse-grained model for the microscopic structure of the porous electrodes and room-temperature ionic liquids. The theoretical results indicate that a highly polar, low-molecular-weight additive is able to drastically increase the EDLC capacitance at low bulk concentration. Additionally, the additive is able to dampen the oscillatory dependence of the capacitance on the pore size, thereby boosting the performance of amorphous electrode materials. Finally, the theoretical predictions are directly testable with experiments and provide new insights into the additive effects on EDL properties.

  11. Ionic liquid-based dispersive microextraction of nitro toluenes in water samples

    International Nuclear Information System (INIS)

    Berton, Paula; Regmi, Bishnu P.; Spivak, David A.; Warner, Isiah M.

    2014-01-01

    We describe a method for dispersive liquid-liquid microextraction of nitrotoluene-based compounds. This method is based on use of the room temperature ionic liquid (RTIL) 1-hexyl-4-methylpyridinium bis(trifluoromethylsulfonyl)imide as the accepting phase, and is shown to work well for extraction of 4-nitrotoluene, 2,4-dinitrotoluene, and 2,4,6-trinitrotoluene. Separation and subsequent detection of analytes were accomplished via HPLC with UV detection. Several parameters that influence the efficiency of the extraction were optimized using experimental design. In this regard, a Plackett–Burman design was used for initial screening, followed by a central composite design to further optimize the influencing variables. For a 5-mL water sample, the optimized IL-DLLME procedure requires 26 mg of the RTIL as extraction solvent and 680 μL of methanol as the dispersant. Under optimum conditions, limits of detection (LODs) are lower than 1.05 μg L −1 . Relative standard deviations for 6 replicate determinations at a 4 μg L −1 analyte level are <4.3 % (calculated using peak areas). Correlation coefficients of >0.998 were achieved. This method was successfully applied to extraction and determination of nitrotoluene-based compounds in spiked tap and lake water samples. (author)

  12. Simultaneous extraction and concentration of water pollution tracers using ionic-liquid-based systems.

    Science.gov (United States)

    Dinis, Teresa B V; Passos, Helena; Lima, Diana L D; Sousa, Ana C A; Coutinho, João A P; Esteves, Valdemar I; Freire, Mara G

    2017-07-29

    Human activities are responsible for the release of innumerous substances into the aquatic environment. Some of these substances can be used as pollution tracers to identify contamination sources and to prioritize monitoring and remediation actions. Thus, their identification and quantification are of high priority. However, due to their presence in complex matrices and at significantly low concentrations, a pre-treatment/concentration step is always required. As an alternative to the currently used pre-treatment methods, mainly based on solid-phase extractions, aqueous biphasic systems (ABS) composed of ionic liquids (ILs) and K 3 C 6 H 5 O 7 are here proposed for the simultaneous extraction and concentration of mixtures of two important pollution tracers, caffeine (CAF) and carbamazepine (CBZ). An initial screening of the IL chemical structure was carried out, with extraction efficiencies of both tracers to the IL-rich phase ranging between 95 and 100%, obtained in a single-step. These systems were then optimized in order to simultaneously concentrate CAF and CBZ from water samples followed by HPLC-UV analysis, for which no interferences of the ABS phase-forming components and other interferents present in a wastewater effluent sample have been found. Based on the saturation solubility data of both pollution tracers in the IL-rich phase, the maximum estimated concentration factors of CAF and CBZ are 28595- and 8259-fold. IL-based ABS can be thus envisioned as effective pre-treatment techniques of environmentally-related aqueous samples for a more accurate monitoring of mixtures of pollution tracers. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Applications and Properties of Ionic Liquid- Based Gels and Soft Solid Composites

    Science.gov (United States)

    Voss, Bret Alan McGinness

    2011-12-01

    Solid-liquid composites (gels) have a combination of properties that afford new material applications in which high solute diffusion is desirable. These composites have a soft-solid mechanical integrity and will not flow under gravity, but entrain a liquid matrix (i.e. 60-98 mass %) which allows for high diffusion and high reactivity. Room temperature ionic liquid (RTILs) are molten organic salts with a melting point below room temperature and negligible vapor pressure. If the RTILs are used as the liquid component of a gel, then the gel matrix will not evaporate (unlike other organic solvents) and may be used for long term applications. This thesis research applies RTIL gels for two new applications; carbon dioxide/nitrogen separation and chemical warfare agent (CWA) barrier and decontamination. Separating CO2 from the flue gas of coal and gas fired power-plants is an increasingly economically and environmentally important gas separation. In this first study, RTIL gels are cast in a supported membrane and gas permeability and ideal selectivity are measured. The RTIL matrix has an inherent affinity for CO2 and provides a high diffusion, hence high permeability (i.e. 500-700 barrer). The solidifying component is a low molecular-weight organic gelator (LMOG) which through physical bonding interactions (i.e. hydrogen bonding, pi-pi stacking and van der Walls forces) forms an entangled network which provides mechanical stability (i.e. increase trans-membrane pressure required to expel selective material from the support). In these studies two LMOGs and five RTILs are used to make supported gel membranes and determine gas permeability and temperature dependent trends. The second application for RTIL gels is a decontaminating barrier for CWAs and toxic industrial compounds (TICs). In these studies a layer of RTIL gel is applied on top of a substrate contaminated with a CWA simulant (i.e. chloroethylethylsulfide, CEES). The gel performs well as a barrier, preventing CEES

  14. Quantification of amino acids and peptides in an ionic liquid based aqueous two-phase system by LC-MS analysis.

    Science.gov (United States)

    Oppermann, Sebastian; Oppermann, Christina; Böhm, Miriam; Kühl, Toni; Imhof, Diana; Kragl, Udo

    2018-04-25

    Aqueous two-phase systems (ATPS) occur by the mixture of two polymers or a polymer and an inorganic salt in water. It was shown that not only polymers but also ionic liquids in combination with inorganic cosmotrophic salts are able to build ATPS. Suitable for the formation of ionic liquid-based ATPS systems are hydrophilic water miscible ionic liquids. To understand the driving force for amino acid and peptide distribution in IL-ATPS at different pH values, the ionic liquid Ammoeng 110™ and K 2 HPO 4 have been chosen as a test system. To quantify the concentration of amino acids and peptides in the different phases, liquid chromatography and mass spectrometry (LC-MS) technologies were used. Therefore the peptides and amino acids have been processed with EZ:faast™-Kit from Phenomenex for an easy and reliable quantification method even in complex sample matrices. Partitioning is a surface-dependent phenomenon, investigations were focused on surface-related amino acid respectively peptide properties such as charge and hydrophobicity. Only a very low dependence between the amino acids or peptides hydrophobicity and the partition coefficient was found. Nevertheless, the presented results show that electrostatic respectively ionic interactions between the ionic liquid and the amino acids or peptides have a strong impact on their partitioning behavior.

  15. Ultrasound-Assisted Oxidative Desulfurization of Diesel

    OpenAIRE

    Niran K. Ibrahim; Walla A. Noori; Jaffar M. Khasbag

    2016-01-01

    Due to the dramatic environmental impact of sulfur emissions associated with the exhaust of diesel engines, last environmental regulations for ultra-low-sulfur diesel require a very deep desulfurization (up to 15 ppm), which cannot be met by the conventional hydrodesulfurization units alone. The proposed method involves a batch ultrasound-assisted oxidative desulfurization (UAODS) of a previously hydrotreated diesel (containing 480 ppm sulfur) so as to convert the residual sulfur-bearing comp...

  16. Ionic liquid-based single-drop microextraction/gas chromatographic/mass spectrometric determination of benzene, toluene, ethylbenzene and xylene isomers in waters.

    Science.gov (United States)

    Aguilera-Herrador, Eva; Lucena, Rafael; Cárdenas, Soledad; Valcárcel, Miguel

    2008-08-01

    The direct coupling between ionic liquid-based single-drop microextraction and gas chromatography/mass spectrometry is proposed for the rapid and simple determination of benzene, toluene, ethylbenzene and xylenes isomers (BTEX) in water samples. The extraction procedure exploits not only the high affinity of the selected ionic liquid (1-methyl-3-octyl-imidazolium hexaflourophosphate) to these aromatic compounds but also its special properties like viscosity, low vapour pressure and immiscibility with water. All the variables involved in the extraction process have been studied in depth. The developed method allows the determination of these single-ring compounds in water under the reference concentration level fixed by the international legislation. In this case, limits of detection were in the range 20 ng L(-1) (obtained for benzene) and 91 ng L(-1) (for o-xylene). The repeatability of the proposed method, expressed as RSD (n=5), varied between 3.0% (o-xylene) and 5.2% (toluene).

  17. Protic ionic liquids based on the dimeric and oligomeric anions: [(AcO)xH(x-1)]-.

    Science.gov (United States)

    Johansson, K M; Izgorodina, E I; Forsyth, M; MacFarlane, D R; Seddon, K R

    2008-05-28

    We describe a fluidity and conductivity study as a function of composition in N-methylpyrrolidine-acetic acid mixtures. The simple 1 : 1 acid-base mixture appears to form an ionic liquid, but its degree of ionicity is quite low and such liquids are better thought of as poorly dissociated mixtures of acid and base. The composition consisting of 3 moles acetic acid and 1 mole N-methylpyrrolidine is shown to form the highest ionicity mixture in this binary due to the presence of oligomeric anionic species [(AcO)(x)H(x-1)](-) stabilised by hydrogen bonds. These oligomeric species, being weaker bases than the acetate anion, shift the proton transfer equilibrium towards formation of ionic species, thus generating a higher degree of ionicity than is present at the 1 : 1 composition. A Walden plot analysis, thermogravimetric behaviour and proton NMR data, as well as ab initio calculations of the oligomeric species, all support this conclusion.

  18. Development of an ionic-liquid-based dispersive liquid-liquid microextraction method for the determination of antichagasic drugs in human breast milk: Optimization by central composite design.

    Science.gov (United States)

    Padró, Juan M; Pellegrino Vidal, Rocío B; Echevarria, Romina N; Califano, Alicia N; Reta, Mario R

    2015-05-01

    Chagas disease constitutes a major public health problem in Latin America. Human breast milk is a biological sample of great importance for the analysis of therapeutic drugs, as unwanted exposure through breast milk could result in pharmacological effects in the nursing infant. Thus, the goal of breast milk drug analysis is to inquire to which extent a neonate may be exposed to a drug during lactation. In this work, we developed an analytical technique to quantify benznidazole and nifurtimox (the two antichagasic drugs currently available for medical treatment) in human breast milk, with a simple sample pretreatment followed by an ionic-liquid-based dispersive liquid-liquid microextraction combined with high-performance liquid chromatography and UV detection. For this technique, the ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate has been used as the "extraction solvent." A central composite design was used to find the optimum values for the significant variables affecting the extraction process: volume of ionic liquid, volume of dispersant solvent, ionic strength, and pH. At the optimum working conditions, the average recoveries were 77.5 and 89.7%, the limits of detection were 0.06 and 0.09 μg/mL and the interday reproducibilities were 6.25 and 5.77% for benznidazole and nifurtimox, respectively. The proposed methodology can be considered sensitive, simple, robust, accurate, and green. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Ionic Liquid-Based Ultrasonic-Assisted Extraction of Secoisolariciresinol Diglucoside from Flaxseed (Linum usitatissimum L. with Further Purification by an Aqueous Two-Phase System

    Directory of Open Access Journals (Sweden)

    Zhi-Jian Tan

    2015-09-01

    Full Text Available In this work, a two-step extraction methodology of ionic liquid-based ultrasonic-assisted extraction (IL-UAE and ionic liquid-based aqueous two-phase system (IL-ATPS was developed for the extraction and purification of secoisolariciresinol diglucoside (SDG from flaxseed. In the IL-UAE step, several kinds of ILs were investigated as the extractants, to identify the IL that affords the optimum extraction yield. The extraction conditions such as IL concentration, ultrasonic irradiation time, and liquid–solid ratio were optimized using response surface methodology (RSM. In the IL-ATPS step, ATPS formed by adding kosmotropic salts to the IL extract was used for further separation and purification of SDG. The most influential parameters (type and concentration of salt, temperature, and pH were investigated to obtain the optimum extraction efficiency. The maximum extraction efficiency was 93.35% under the optimal conditions of 45.86% (w/w IL and 8.27% (w/w Na2SO4 at 22 °C and pH 11.0. Thus, the combination of IL-UAE and IL-ATPS makes up a simple and effective methodology for the extraction and purification of SDG. This process is also expected to be highly useful for the extraction and purification of bioactive compounds from other important medicinal plants.

  20. Ultrasound-assisted oxidative desulfurization of bitumen

    Science.gov (United States)

    Kamal, Wan Mohamad Ikhwan bin Wan; Okawa, Hirokazu; Kato, Takahiro; Sugawara, Katsuyasu

    2017-07-01

    Bitumen contains a high percentage of sulfur (about 4.6 wt %). A hydrodesulfurization method is used to remove sulfur from bitumen. The drawback of this method is the requirement for a high temperature of >300 °C. Most of the sulfur in bitumen exists as thiophene. Oxidative desulfurization (ODS), involving oxidizing sulfur using H2O2, then removing it using NaOH, allows the removal of sulfur in thiophene at low temperatures. We removed sulfur from bitumen using ODS treatment under ultrasound irradiation, and 52% of sulfur was successfully removed. Additionally, the physical action of ultrasound assisted the desulfurization of bitumen, even at low H2O2 concentrations.

  1. Electrochemistry of poly(3,4-ethylenedioxythiophene)-polyaniline/ Prussian blue electrochromic devices containing an ionic liquid based gel electrolyte film.

    Science.gov (United States)

    Deepa, Melepurath; Awadhia, Arvind; Bhandari, Shweta

    2009-07-21

    Electrochromic devices based on poly(3,4-ethylenedioxythiophene) (PEDOT) as the cathodic coloring electrode and polyaniline (PANI) or Prussian blue (PB) as the counter electrode containing a highly conductive, self-supporting, distensible and transparent polymer-gel electrolyte film encapsulating an ionic liquid, 1-butyl-1-methylpyrrolidiniumbis-(trifluoromethylsulfonyl)imide, have been fabricated. Polarization, charge transfer and diffusion processes control the electrochemistry of the functional electrodes during coloration and bleaching and these phenomena differ when PEDOT and PANI/PB were employed alternately as working electrodes. While the electrochemical impedance response shows good similitude for PEDOT and PANI electrodes, the responses of PEDOT and PB were significantly different in the PEDOT-PB device, especially during reduction of PB, wherein the overall amplitude of the impedance response is enormous. Large values of the coloration efficiency maxima of 281 cm2 C(-1) (lambda = 583 nm) and 274 cm2 C(-1) (lambda = 602 nm), achieved at -1.0 and -1.5 V for the PEDOT PANI and PEDOT-PB devices have been correlated to the particularly low magnitude of charge transfer resistance and high polarization capacitance operative at the PEDOT ionic liquid based electrolyte interface at these dc potentials, thus allowing facile ion-transport and consequently resulting in enhanced absorption modulation. Moderately fast switching kinetics and the ability of these devices to sustain about 2500 cycles of clear-to-dark and dark-to-clear without incurring major losses in the optical contrast, along with the ease of construction of these cells in terms of high scalability and reproducibility of the synthetic procedure for fabrication of the electrochromic films and the ionic liquid based gel electrolyte film, are indicators of the promise these devices hold for practical applications like electrochromic windows and displays.

  2. Ultrasound assisted extraction of bioactive compounds

    Directory of Open Access Journals (Sweden)

    Helena Drmić

    2010-01-01

    Full Text Available Many novel and innovative techniques are nowadays researched and explored in order to replace or improve classical, thermal processing technologies. One of newer technique is technique of minimal food processing, under what we assume ultrasound processing. Ultrasound technology can be very useful for minimal food processing because transmission of acoustic energy through product is fast and complete, which allows reduction in total processing time, and therefore lower energy consumption. Industrial processing is growing more and more waste products, and in desire of preservation of global recourses and energy efficiency, several ways of active compounds extraction techniques are now explored. The goal is to implement novel extraction techniques in food and pharmaceutical industry as well in medicine. Ultrasound assisted extraction of bioactive compounds offers increase in yield, and reduction or total avoiding of solvent usage. Increase in temperature of treatment is controlled and restricted, thereby preserving extracted bioactive compounds. In this paper, several methods of ultrasound assisted extraction of bioactive compounds from plant materials are shown. Ultrasound can improve classic mechanisms of extraction, and thereby offer novel possibilities of commercial extraction of desired compounds. Application of sonochemistry (ultrasound chemistry is providing better yield in desired compounds and reduction in treatment time.

  3. Ionic liquid-based microwave-assisted dispersive liquid-liquid microextraction and derivatization of sulfonamides in river water, honey, milk, and animal plasma.

    Science.gov (United States)

    Xu, Xu; Su, Rui; Zhao, Xin; Liu, Zhuang; Zhang, Yupu; Li, Dan; Li, Xueyuan; Zhang, Hanqi; Wang, Ziming

    2011-11-30

    The ionic liquid-based microwave-assisted dispersive liquid-liquid microextraction (IL-based MADLLME) and derivatization was applied for the pretreatment of six sulfonamides (SAs) prior to the determination by high-performance liquid chromatography (HPLC). By adding methanol (disperser), fluorescamine solution (derivatization reagent) and ionic liquid (extraction solvent) into sample, extraction, derivatization, and preconcentration were continuously performed. Several experimental parameters, such as the type and volume of extraction solvent, the type and volume of disperser, amount of derivatization reagent, microwave power, microwave irradiation time, pH of sample solution, and ionic strength were investigated and optimized. When the microwave power was 240 W, the analytes could be derivatized and extracted simultaneously within 90 s. The proposed method was applied to the analysis of river water, honey, milk, and pig plasma samples, and the recoveries of analytes obtained were in the range of 95.0-110.8, 95.4-106.3, 95.0-108.3, and 95.7-107.7, respectively. The relative standard deviations varied between 1.5% and 7.3% (n=5). The results showed that the proposed method was a rapid, convenient and feasible method for the determination of SAs in liquid samples. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. Determination of trihalomethanes in waters by ionic liquid-based single drop microextraction/gas chromatographic/mass spectrometry.

    Science.gov (United States)

    Aguilera-Herrador, Eva; Lucena, Rafael; Cárdenas, Soledad; Valcárcel, Miguel

    2008-10-31

    A simple, rapid, solventless method for the determination of trihalomethanes (THMs) (chloroform, bromodichloromethane, dibromochloromethane and bromoform) in water samples is presented. The analytes are extracted from the headspace of the aqueous matrix into a 2 microL drop of the ionic liquid 1-octyl-3-methyl-imidazolium hexafluorophosphate working at 30 degrees C for 30 min. The separation and detection of the target compounds is accomplished by gas chromatography/mass spectrometry owing to the use of an interface that efficiently transfers the analytes extracted in the ionic liquid drop to the gas chromatograph while preventing the ionic liquid from entering the column. The detection limits obtained are below the values compelled by the legislation, ranging from 0.5 microg L(-1) for chloroform and bromodichloromethane to 0.9 microg L(-1) for dibromochloromethane. The use of ionic liquid in the extraction procedure avoids the use of organic solvents and leads to relative standard deviations that range from 3.1% to 4.8%.

  5. Ionic liquid-based microwave-assisted dispersive liquid-liquid microextraction and derivatization of sulfonamides in river water, honey, milk, and animal plasma

    Energy Technology Data Exchange (ETDEWEB)

    Xu Xu; Su Rui; Zhao Xin; Liu Zhuang; Zhang Yupu; Li Dan; Li Xueyuan; Zhang Hanqi [College of Chemistry, Jilin University, Changchun 130012 (China); Wang Ziming, E-mail: analchem@jlu.edu.cn [College of Chemistry, Jilin University, Changchun 130012 (China)

    2011-11-30

    Graphical abstract: The extraction and derivatization efficiency of SAs is dependent on type and volume of extraction solvent, type and volume of disperser, microwave power and irradiation time, volume of derivatization reagent, pH of sample solution as well as ionic strength. Highlights: Black-Right-Pointing-Pointer A new, rapid and sensitive method for determining sulfonamides (SAs) was proposed. Black-Right-Pointing-Pointer Derivatization, extraction and preconcentration of SAs were performed in one step. Black-Right-Pointing-Pointer IL-based MADLLME and derivatization were first applied for the determination of SAs. Black-Right-Pointing-Pointer Trace SAs in river water, honey, milk, and pig plasma were determined. - Abstract: The ionic liquid-based microwave-assisted dispersive liquid-liquid microextraction (IL-based MADLLME) and derivatization was applied for the pretreatment of six sulfonamides (SAs) prior to the determination by high-performance liquid chromatography (HPLC). By adding methanol (disperser), fluorescamine solution (derivatization reagent) and ionic liquid (extraction solvent) into sample, extraction, derivatization, and preconcentration were continuously performed. Several experimental parameters, such as the type and volume of extraction solvent, the type and volume of disperser, amount of derivatization reagent, microwave power, microwave irradiation time, pH of sample solution, and ionic strength were investigated and optimized. When the microwave power was 240 W, the analytes could be derivatized and extracted simultaneously within 90 s. The proposed method was applied to the analysis of river water, honey, milk, and pig plasma samples, and the recoveries of analytes obtained were in the range of 95.0-110.8, 95.4-106.3, 95.0-108.3, and 95.7-107.7, respectively. The relative standard deviations varied between 1.5% and 7.3% (n = 5). The results showed that the proposed method was a rapid, convenient and feasible method for the determination

  6. Ionic liquid-based microwave-assisted dispersive liquid–liquid microextraction and derivatization of sulfonamides in river water, honey, milk, and animal plasma

    International Nuclear Information System (INIS)

    Xu Xu; Su Rui; Zhao Xin; Liu Zhuang; Zhang Yupu; Li Dan; Li Xueyuan; Zhang Hanqi; Wang Ziming

    2011-01-01

    Graphical abstract: The extraction and derivatization efficiency of SAs is dependent on type and volume of extraction solvent, type and volume of disperser, microwave power and irradiation time, volume of derivatization reagent, pH of sample solution as well as ionic strength. Highlights: ► A new, rapid and sensitive method for determining sulfonamides (SAs) was proposed. ► Derivatization, extraction and preconcentration of SAs were performed in one step. ► IL-based MADLLME and derivatization were first applied for the determination of SAs. ► Trace SAs in river water, honey, milk, and pig plasma were determined. - Abstract: The ionic liquid-based microwave-assisted dispersive liquid–liquid microextraction (IL-based MADLLME) and derivatization was applied for the pretreatment of six sulfonamides (SAs) prior to the determination by high-performance liquid chromatography (HPLC). By adding methanol (disperser), fluorescamine solution (derivatization reagent) and ionic liquid (extraction solvent) into sample, extraction, derivatization, and preconcentration were continuously performed. Several experimental parameters, such as the type and volume of extraction solvent, the type and volume of disperser, amount of derivatization reagent, microwave power, microwave irradiation time, pH of sample solution, and ionic strength were investigated and optimized. When the microwave power was 240 W, the analytes could be derivatized and extracted simultaneously within 90 s. The proposed method was applied to the analysis of river water, honey, milk, and pig plasma samples, and the recoveries of analytes obtained were in the range of 95.0–110.8, 95.4–106.3, 95.0–108.3, and 95.7–107.7, respectively. The relative standard deviations varied between 1.5% and 7.3% (n = 5). The results showed that the proposed method was a rapid, convenient and feasible method for the determination of SAs in liquid samples.

  7. Electrodeposition of compact zinc from the hydrophobic Brønsted acidic ionic liquid-based electrolytes and the study of zinc stability along with the acidity manipulation

    International Nuclear Information System (INIS)

    Chen, Yi-Han; Yeh, Hsin-Wen; Lo, Nai-Chang; Chiu, Chen-Wei; Sun, I-Wen; Chen, Po-Yu

    2017-01-01

    Highlights: • Compact Zn with no crack is deposited from protic ionic liquid-based electrolytes. • The ionic liquid is composed of the protonated betaine ion. • This ionic liquid is hydrophobic and zinc oxide is soluble in it. • The effects of co-solvents, propylene carbonate and water, are studied. • The Zn stripping/deposition efficiency can be manipulated via acidity adjustment. - Abstract: Compact crystalline zinc was electrodeposited on stainless-steel electrode (SS) via potentiostatic/galvanostatic electrolysis from the hydrophobic Brønsted acidic ionic liquid, protonated betaine bis((trifluoromethyl)sulfonyl)imide (IL [Hbet][TFSI]), −based electrolytes containing ZnCl 2 or ZnO under argon or ambient air atmosphere. Approximate 10 wt% of propylene carbonate and water, respectively, were used as the co-solvents for [Hbet][TFSI] to form the IL-based electrolytes. The efficiency of zinc deposition/stripping, which is significantly affected by the Brønsted acidity of the IL-based electrolytes, was studied at glassy carbon electrode (GC) to evaluate the stability of the zinc electrodeposits along with the electrolyte acidity. The stability is very poor for the zinc electrodeposits obtained from ZnCl 2 solution. However, it increases with increasing the quantity of ZnO or urea in the electrolytes; the former neutralize the dissociable protons in [Hbet] cations to form water, and the latter may form H-bonding with [Hbet] or be protonated to form the weakly acidic cations [HUrea]. Both suppress the reaction between the Zn electrodeposits and protons. The stability of the Zn electrodeposits, therefore, can be improved via the manipulation of the IL acidity.

  8. Determination of Sunset Yellow and Tartrazine in Food Samples by Combining Ionic Liquid-Based Aqueous Two-Phase System with High Performance Liquid Chromatography

    Science.gov (United States)

    Sha, Ou; Zhu, Xiashi; Feng, Yanli; Ma, Weixing

    2014-01-01

    We proposed a simple and effective method, by coupling ionic liquid-based aqueous two-phase systems (IL-ATPSs) with high performance liquid chromatography (HPLC), for the analysis of determining tartrazine and sunset yellow in food samples. Under the optimized conditions, IL-ATPSs generated an extraction efficiency of 99% for both analytes, which could then be directly analyzed by HPLC without further treatment. Calibration plots were linear in the range of 0.01–50.0 μg/mL for both Ta and SY. The limits of detection were 5.2 ng/mL for Ta and 6.9 ng/mL for SY. This method proves successful for the separation/analysis of tartrazine and sunset yellow in soft drink sample, candy sample, and instant powder drink and leads to consistent results as obtained from the Chinese national standard method. PMID:25538857

  9. Determination of Sunset Yellow and Tartrazine in Food Samples by Combining Ionic Liquid-Based Aqueous Two-Phase System with High Performance Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    Ou Sha

    2014-01-01

    Full Text Available We proposed a simple and effective method, by coupling ionic liquid-based aqueous two-phase systems (IL-ATPSs with high performance liquid chromatography (HPLC, for the analysis of determining tartrazine and sunset yellow in food samples. Under the optimized conditions, IL-ATPSs generated an extraction efficiency of 99% for both analytes, which could then be directly analyzed by HPLC without further treatment. Calibration plots were linear in the range of 0.01–50.0 μg/mL for both Ta and SY. The limits of detection were 5.2 ng/mL for Ta and 6.9 ng/mL for SY. This method proves successful for the separation/analysis of tartrazine and sunset yellow in soft drink sample, candy sample, and instant powder drink and leads to consistent results as obtained from the Chinese national standard method.

  10. Determination of sunset yellow and tartrazine in food samples by combining ionic liquid-based aqueous two-phase system with high performance liquid chromatography.

    Science.gov (United States)

    Sha, Ou; Zhu, Xiashi; Feng, Yanli; Ma, Weixing

    2014-01-01

    We proposed a simple and effective method, by coupling ionic liquid-based aqueous two-phase systems (IL-ATPSs) with high performance liquid chromatography (HPLC), for the analysis of determining tartrazine and sunset yellow in food samples. Under the optimized conditions, IL-ATPSs generated an extraction efficiency of 99% for both analytes, which could then be directly analyzed by HPLC without further treatment. Calibration plots were linear in the range of 0.01-50.0 μg/mL for both Ta and SY. The limits of detection were 5.2 ng/mL for Ta and 6.9 ng/mL for SY. This method proves successful for the separation/analysis of tartrazine and sunset yellow in soft drink sample, candy sample, and instant powder drink and leads to consistent results as obtained from the Chinese national standard method.

  11. Self-Assembled Polymeric Ionic Liquid-Functionalized Cellulose Nano-crystals: Constructing 3D Ion-conducting Channels Within Ionic Liquid-based Composite Polymer Electrolytes.

    Science.gov (United States)

    Shi, Qing Xuan; Xia, Qing; Xiang, Xiao; Ye, Yun Sheng; Peng, Hai Yan; Xue, Zhi Gang; Xie, Xiao Lin; Mai, Yiu-Wing

    2017-09-04

    Composite polymeric and ionic liquid (IL) electrolytes are some of the most promising electrolyte systems for safer battery technology. Although much effort has been directed towards enhancing the transport properties of polymer electrolytes (PEs) through nanoscopic modification by incorporating nano-fillers, it is still difficult to construct ideal ion conducting networks. Here, a novel class of three-dimensional self-assembled polymeric ionic liquid (PIL)-functionalized cellulose nano-crystals (CNC) confining ILs in surface-grafted PIL polymer chains, able to form colloidal crystal polymer electrolytes (CCPE), is reported. The high-strength CNC nano-fibers, decorated with PIL polymer chains, can spontaneously form three-dimensional interpenetrating nano-network scaffolds capable of supporting electrolytes with continuously connected ion conducting networks with IL being concentrated in conducting domains. These new CCPE have exceptional ionic conductivities, low activation energies (close to bulk IL electrolyte with dissolved Li salt), high Li + transport numbers, low interface resistances and improved interface compatibilities. Furthermore, the CCPE displays good electrochemical properties and a good battery performance. This approach offers a route to leak-free, non-flammable and high ionic conductivity solid-state PE in energy conversion devices. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Ionic liquid-based air-assisted liquid-liquid microextraction followed by high performance liquid chromatography for the determination of five fungicides in juice samples.

    Science.gov (United States)

    You, Xiangwei; Chen, Xiaochu; Liu, Fengmao; Hou, Fan; Li, Yiqiang

    2018-01-15

    A novel and simple ionic liquid-based air-assisted liquid-liquid microextraction technique combined with high performance liquid chromatography was developed to analyze five fungicides in juice samples. In this method, ionic liquid was used instead of a volatile organic solvent as the extraction solvent. The emulsion was formed by pulling in and pushing out the mixture of aqueous sample solution and extraction solvent repeatedly using a 10mL glass syringe. No organic dispersive solvent was required. Under the optimized conditions, the limits of detection (LODs) were 0.4-1.8μgL -1 at a signal-to-noise ratio of 3. The limits of quantification (LOQs) set as the lowest spiking levels with acceptable recovery in juices were 10μgL -1 , except for fludioxonil whose LOQ was 20μgL -1 . The proposed method was applied to determine the target fungicides in juice samples, and acceptable recoveries ranging from 74.9% to 115.4% were achieved. Copyright © 2017. Published by Elsevier Ltd.

  13. Optimization of Ionic Liquid Based Simultaneous Ultrasonic- and Microwave-Assisted Extraction of Rutin and Quercetin from Leaves of Velvetleaf (Abutilon theophrasti by Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Chunjian Zhao

    2014-01-01

    Full Text Available An ionic liquids based simultaneous ultrasonic and microwave assisted extraction (ILs-UMAE method has been proposed for the extraction of rutin (RU, quercetin (QU, from velvetleaf leaves. The influential parameters of the ILs-UMAE were optimized by the single factor and the central composite design (CCD experiments. A 2.00 M 1-butyl-3-methylimidazolium bromide ([C4mim]Br was used as the experimental ionic liquid, extraction temperature 60°C, extraction time 12 min, liquid-solid ratio 32 mL/g, microwave power of 534 W, and a fixed ultrasonic power of 50 W. Compared to conventional heating reflux extraction (HRE, the RU and QU extraction yields obtained by ILs-UMAE were, respectively, 5.49 mg/g and 0.27 mg/g, which increased, respectively, 2.01-fold and 2.34-fold with the recoveries that were in the range of 97.62–102.36% for RU and 97.33–102.21% for QU with RSDs lower than 3.2% under the optimized UMAE conditions. In addition, the shorter extraction time was used in ILs-UMAE, compared with HRE. Therefore, ILs-UMAE was a rapid and an efficient method for the extraction of RU and QU from the leaves of velvetleaf.

  14. Performance analysis of absorption heat transformer cycles using ionic liquids based on imidazolium cation as absorbents with 2,2,2-trifluoroethanol as refrigerant

    International Nuclear Information System (INIS)

    Ayou, Dereje S.; Currás, Moisés R.; Salavera, Daniel; García, Josefa; Bruno, Joan C.; Coronas, Alberto

    2014-01-01

    Highlights: • TFE + [emim][BF 4 ] (or [bmim][BF 4 ]) absorption heat transformer cycles are studied. • Influence of various operating conditions on cycle’s performance is investigated. • Performance comparisons with H 2 O + LiBr and TFE + TEGDME cycles are done. • Enthalpy data for TFE + [emim][BF 4 ] (or [bmim][BF 4 ]) liquid mixtures are calculated. • TFE + [emim][BF 4 ] (or [bmim][BF 4 ]) cycles have higher gross temperature lift (GTL). - Abstract: A detailed thermodynamic performance analysis of a single-stage absorption heat transformer and double absorption heat transformer cycles using new working pairs composed of ionic liquids (1-ethyl-3-methylimidazolium tetrafluoroborate ([emim][BF 4 ]) and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF 4 ])) as absorbent and 2,2,2-trifluoroethanol (TFE) as refrigerant has been studied. Several performance indicators were used to evaluate and compare the performance of the cycles using the TFE + [emim][BF 4 ] and TFE + [bmim][BF 4 ] working pairs with the conventional H 2 O + LiBr and organic TFE + TEGDME working pairs. The obtained results show that the ionic liquid based working pairs are suitable candidates to replace the conventional H 2 O + LiBr working pairs in order to avoid the disadvantages associated with it mainly crystallization and corrosion and also they perform better (higher gross temperature lift) than TFE + TEGDME working pair at several operating conditions considered in this work

  15. Detection of Organophosphorus Pesticides in Wheat by Ionic Liquid-Based Dispersive Liquid-Liquid Microextraction Combined with HPLC

    Directory of Open Access Journals (Sweden)

    Wei Liu

    2018-01-01

    Full Text Available Food safety issues closely related to human health have always received widespread attention from the world society. As a basic food source, wheat is the fundamental support of human survival; therefore, the detection of pesticide residues in wheat is very necessary. In this work, the ultrasonic-assisted ionic liquid-dispersive liquid-liquid microextraction (DLLME method was firstly proposed, and the extraction and analysis of three organophosphorus pesticides were carried out by combining high-performance liquid chromatography (HPLC. The extraction efficiencies of three ionic liquids with bis(trifluoromethylsulfonylimide (Tf2N anion were compared by extracting organophosphorus in wheat samples. It was found that the use of 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonylimide ([OMIM][Tf2N] had both high enrichment efficiency and appropriate extraction recovery. Finally, the method was used for the determination of three wheat samples, and the recoveries of them were 74.8–112.5%, 71.8–104.5%, and 83.8–115.5%, respectively. The results show that the method proposed is simple, fast, and efficient, which can be applied to the extraction of organic matters in wheat samples.

  16. Highly selective ionic liquid-based microextraction method for sensitive trace cobalt determination in environmental and biological samples

    International Nuclear Information System (INIS)

    Berton, Paula; Wuilloud, Rodolfo G.

    2010-01-01

    A simple and rapid dispersive liquid-liquid microextraction procedure based on an ionic liquid (IL-DLLME) was developed for selective determination of cobalt (Co) with electrothermal atomic absorption spectrometry (ETAAS) detection. Cobalt was initially complexed with 1-nitroso-2-naphtol (1N2N) reagent at pH 4.0. The IL-DLLME procedure was then performed by using a few microliters of the room temperature ionic liquid (RTIL) 1-hexyl-3-methylimidazolium hexafluorophosphate [C 6 mim][PF 6 ] as extractant while methanol was the dispersant solvent. After microextraction procedure, the Co-enriched RTIL phase was solubilized in methanol and directly injected into the graphite furnace. The effect of several variables on Co-1N2N complex formation, extraction with the dispersed RTIL phase, and analyte detection with ETAAS, was carefully studied in this work. An enrichment factor of 120 was obtained with only 6 mL of sample solution and under optimal experimental conditions. The resultant limit of detection (LOD) was 3.8 ng L -1 , while the relative standard deviation (RSD) was 3.4% (at 1 μg L -1 Co level and n = 10), calculated from the peak height of absorbance signals. The accuracy of the proposed methodology was tested by analysis of a certified reference material. The method was successfully applied for the determination of Co in environmental and biological samples.

  17. Sono- and photoelectrocatalytic processes for the removal of ionic liquids based on the 1-butyl-3-methylimidazolium cation.

    Science.gov (United States)

    Mena, Ismael F; Cotillas, Salvador; Díaz, Elena; Sáez, Cristina; Mohedano, Ángel F; Rodrigo, Manuel A

    2017-12-06

    In this work, sono- and photoelectrolysis of synthetic wastewaters polluted with the ionic liquids 1-Butyl-3-methylimidazolium acetate (BmimAc) and chloride (BmimCl) were investigated with diamond anodes. The results were compared to those attained by enhancing bare electrolysis with irradiation by UV light or with the application of high-frequency ultrasound (US). Despite its complex heterocyclic structure, the Bmim + cation was successfully depleted with the three technologies that were tested and was mainly transformed into four different organic intermediates, an inorganic nitrogen species and carbon dioxide. Regardless of the technology that was evaluated, removal of the heterocyclic ring is much less efficient (and much slower) than oxidation of the counter ion. In turn, the counter ion influences the rate of removal of the ionic liquid cation. Thus, the electrolysis and photoelectrolysis of BmimAc are much less efficient than sonoelectrolysis, but their differences become much less important in the case of BmimCl. In this later case, the most efficient technology is photoelectrolysis. This result is directly related to the generation of free radicals in the solution by irradiation of the electrochemical system with UV light, which contributes significantly to the removal of Bmim + . Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Preparation of a polymeric ionic liquid-based adsorbent for stir cake sorptive extraction of preservatives in orange juices and tea drinks

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Lei; Huang, Xiaojia, E-mail: hxj@xmu.edu.cn

    2016-04-15

    In this study, a new polymeric ionic liquid-based adsorbent was prepared and used as the extraction medium of stir cake sorptive extraction (SCSE) of three organic acid preservatives, namely, p-hydroxybenzoic acid, sorbic acid and cinnamic acid. The adsorbent was synthesized by the copolymerization of 1-ally-3-vinylimidazolium chloride (AV) and divinylbenzene (DVB) in the presence of a porogen solvent containing 1-propanol and 1,4-butanediol. The effect of the content of monomer and the porogen solvent in the polymerization mixture on the extraction performance was investigated thoroughly. The adsorbent was characterized by infrared spectroscopy, elemental analysis, scanning electron microscopy and mercury intrusion porosimetry. To obtain the optimal extraction conditions of SCSE/AVDVB for target analytes, key parameters including desorption solvent, adsorption and desorption time, ionic strength and pH value in sample matrix were studied in detail. The results showed that under the optimized conditions, the SCSE/AVDVB could extract the preservatives effectively through multiply interactions. At the same time, a simple and sensitive method by combining SCSE/AVDVB and high-performance liquid chromatography with diode array detection was developed for the simultaneous analysis of the target preservatives in orange juices and tea drinks. Low limits of detection (S/N = 3) and quantification limits (S/N = 10) of the proposed method for the target analytes were achieved within the range of 0.012–0.23 μg/L and 0.039–0.42 μg/L, respectively. The precision of the proposed method was evaluated in terms of intra- and inter-assay variability calculated as relative standard deviation (RSD), and it was found that the values were all below 10%. Finally, the proposed method was used to detect preservatives in different orange juice and tea drink samples successfully. The recoveries were in the range of 71.9–116%, and the RSDs were below 10% in the all cases

  19. Preparation of a polymeric ionic liquid-based adsorbent for stir cake sorptive extraction of preservatives in orange juices and tea drinks

    International Nuclear Information System (INIS)

    Chen, Lei; Huang, Xiaojia

    2016-01-01

    In this study, a new polymeric ionic liquid-based adsorbent was prepared and used as the extraction medium of stir cake sorptive extraction (SCSE) of three organic acid preservatives, namely, p-hydroxybenzoic acid, sorbic acid and cinnamic acid. The adsorbent was synthesized by the copolymerization of 1-ally-3-vinylimidazolium chloride (AV) and divinylbenzene (DVB) in the presence of a porogen solvent containing 1-propanol and 1,4-butanediol. The effect of the content of monomer and the porogen solvent in the polymerization mixture on the extraction performance was investigated thoroughly. The adsorbent was characterized by infrared spectroscopy, elemental analysis, scanning electron microscopy and mercury intrusion porosimetry. To obtain the optimal extraction conditions of SCSE/AVDVB for target analytes, key parameters including desorption solvent, adsorption and desorption time, ionic strength and pH value in sample matrix were studied in detail. The results showed that under the optimized conditions, the SCSE/AVDVB could extract the preservatives effectively through multiply interactions. At the same time, a simple and sensitive method by combining SCSE/AVDVB and high-performance liquid chromatography with diode array detection was developed for the simultaneous analysis of the target preservatives in orange juices and tea drinks. Low limits of detection (S/N = 3) and quantification limits (S/N = 10) of the proposed method for the target analytes were achieved within the range of 0.012–0.23 μg/L and 0.039–0.42 μg/L, respectively. The precision of the proposed method was evaluated in terms of intra- and inter-assay variability calculated as relative standard deviation (RSD), and it was found that the values were all below 10%. Finally, the proposed method was used to detect preservatives in different orange juice and tea drink samples successfully. The recoveries were in the range of 71.9–116%, and the RSDs were below 10% in the all cases

  20. The influence of pore size and surface area of activated carbons on the performance of ionic liquid based supercapacitors.

    Science.gov (United States)

    Pohlmann, Sebastian; Lobato, Belén; Centeno, Teresa A; Balducci, Andrea

    2013-10-28

    This study analyses and compares the behaviour of 5 commercial porous carbons in the ionic liquid N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR14TFSI) and its mixture with propylene carbonate (PC) as electrolytes. The results of this investigation show that the existence of a distribution of pore sizes and/or constrictions at the entrance of the pores leads to significant changes in the specific capacitance of the investigated materials. The use of PYR14TFSI as an electrolyte has a positive effect on the EDLC energy storage, but its high viscosity limits the power density. The mixture 50 : 50 wt% propylene carbonate-PYR14TFSI provides high operative voltage as well as low viscosity and thus notably enhances EDLC operation.

  1. Effect of lithium salts addition on the ionic liquid based extraction of essential oil from Farfarae Flos.

    Science.gov (United States)

    Li, Zhen-Yu; Zhang, Sha-Sha; Jie-Xing; Qin, Xue-Mei

    2015-01-01

    In this study, an ionic liquids (ILs) based extraction approach has been successfully applied to the extraction of essential oil from Farfarae Flos, and the effect of lithium chloride was also investigated. The results indicated that the oil yields can be increased by the ILs, and the extraction time can be reduced significantly (from 4h to 2h), compared with the conventional water distillation. The addition of lithium chloride showed different effect according to the structures of ILs, and the oil yields may be related with the structure of cation, while the chemical compositions of essential oil may be related with the anion. The reduction of extraction time and remarkable higher efficiency (5.41-62.17% improved) by combination of lithium salt and proper ILs supports the suitability of the proposed approach. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Nitrogen-doped carbon capsules via poly(ionic liquid)-based layer-by-layer assembly.

    Science.gov (United States)

    Zhao, Qiang; Fellinger, Tim-Patrick; Antonietti, Markus; Yuan, Jiayin

    2012-07-13

    Layer-by-layer (LbL) assembly technique is applied for the first time for the preparation of nitrogen-doped carbon capsules. This approach uses colloid silica as template and two polymeric deposition components, that is, poly(ammonium acrylate) and a poly (ionic liquid) poly(3-cyanomethyl-1-vinylimidazolium bromide), which acts as both the carbon precursor and nitrogen source. Nitrogen-doped carbon capsules are prepared successfully by polymer wrapping, subsequent carbonization and template removal. The as-synthesized carbon capsules contain ≈7 wt% of nitrogen and have a structured specific surface area of 423 m(2) g(-1). Their application as supercapacitor has been briefly introduced. This work proves that LbL assembly methodology is available for preparing carbon structures of complex morphology. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Influence of polyoxyethylene phytosterol addition in ionic liquid-based electrolyte on photovoltaic performance of dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Takahashi, Masashi; Sato, Kei; Sakurai, Sho; Kobayashi, Koichi

    2016-01-01

    Highlights: • The ionic liquid solution of less solvophilic BPS exhibits a better surface active property and a weaker dye-desorption effect. • Photovoltaic performances of the N719- and NKX2677-sensitized DSSCs can be improved by the BPS addition to the IL-based electrolyte. • BPS added to the electrolyte plays a key role in reducing charge-transfer resistance and increasing electron lifetime in the TiO 2 electrode. - Abstract: In this work, we studied influence of polyoxyethylene phytosterol (BPS) addition in ionic liquid (IL)-based electrolyte on photovoltaic performance of dye-sensitized solar cells (DSSCs) using 1-methyl-3-propylimidazolium iodide as an IL. Surface tension, photocurrent density-voltage characteristics and electrochemical impedance spectra were measured to clarify the role of BPS in the DSSCs using three different dyes. The results showed that the IL solution of less solvophilic BPS-EO5 exhibited a better surface active property and a weaker dye-desorption effect than BPS-EO30 and BPS-PO7/EO30. Short-circuit current densities of the N719- and NKX2677-sensitized cells were found to be noticeably increased by the addition of either BPS-EO5 or BPS-EO30 to the IL-based electrolyte in the concentration range of 0.001–0.01 mol dm −3 . Enhanced photovoltaic conversion efficiencies were obtained for these DSSCs, which most likely resulted from the effects of BPS on reducing charge-transfer resistance at the TiO 2 /dye/electrolyte interface and on increasing electron lifetime within the TiO 2 photoanode.

  4. Proton-conducting ionic liquid-based proton exchange membrane fuel cell membranes: The key role of ionomer-ionic liquid interaction

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, Mathieu; Cointeaux, Laure; Iojoiu, Cristina; Lepretre, Jean-Claude; Sanchez, Jean-Yves [LEPMI, UMR 5631, CNRS-INP-UJF, PHELMA-Campus, BP.75, 1130 rue de la Piscine, 38402 Saint-Martin-d' Heres Cedex (France); Molmeret, Yannick; El Kissi, Nadia [Laboratoire de Rheologie, UMR 5520 CNRS-INPG-UJF, ENSHMG, BP 53, 38041 Grenoble (France); Judeinstein, Patrick [Institut de Chimie Moleculaire et des Materiaux d' Orsay (UMR 8182), Batiment 410, Universite Paris-Sud 11, 91405 Orsay Cedex (France)

    2010-09-15

    The paper deals with the synthesis and characterisation of proton-conducting ionic liquids (PCILs) and their polymer electrolytes obtained by blending modified Nafion membranes with different concentrations of PCILs. The PCILs are obtained by the neutralization of triethylamine with different organic acids. The first part of the paper studies the influence of acidity and acid structure on PCIL thermal and electrochemical performance, while the second part examines membrane conductivity and reveals it to depend more on PCIL structure than on its intrinsic conductivity. At 130 C, conductivities exceeding 10 mS cm{sup -1} were obtained in fully anhydrous conditions. (author)

  5. Polymeric ionic liquid-based portable tip microextraction device for on-site sample preparation of water samples.

    Science.gov (United States)

    Chen, Lei; Pei, Junxian; Huang, Xiaojia; Lu, Min

    2018-06-05

    On-site sample preparation is highly desired because it avoids the transportation of large-volume samples and ensures the accuracy of the analytical results. In this work, a portable prototype of tip microextraction device (TMD) was designed and developed for on-site sample pretreatment. The assembly procedure of TMD is quite simple. Firstly, polymeric ionic liquid (PIL)-based adsorbent was in-situ prepared in a pipette tip. After that, the tip was connected with a syringe which was driven by a bidirectional motor. The flow rates in adsorption and desorption steps were controlled accurately by the motor. To evaluate the practicability of the developed device, the TMD was used to on-site sample preparation of waters and combined with high-performance liquid chromatography with diode array detection to measure trace estrogens in water samples. Under the most favorable conditions, the limits of detection (LODs, S/N = 3) for the target analytes were in the range of 4.9-22 ng/L, with good coefficients of determination. Confirmatory study well evidences that the extraction performance of TMD is comparable to that of the traditional laboratory solid-phase extraction process, but the proposed TMD is more simple and convenient. At the same time, the TMD avoids complicated sampling and transferring steps of large-volume water samples. Copyright © 2018 Elsevier B.V. All rights reserved.

  6. Tuning the morphology and structure of nanocarbons with activating agents for ultrafast ionic liquid-based supercapacitors

    Science.gov (United States)

    Cui, Yongpeng; Wang, Huanlei; Mao, Nan; Yu, Wenhua; Shi, Jing; Huang, Minghua; Liu, Wei; Chen, Shougang; Wang, Xin

    2017-09-01

    The increasing demand for supercapacitors with high energy and power density has attracted extensive attention in designing advanced carbon materials with high accessible surface area, hierarchical porosity, and 2D/3D morphology. Here, we report a new approach to tune the morphology and structure of the nanocarbons by using methyl cellulose as the precursor. Due to the varying effect of different activating agents, the interconnected sheet-like carbon with a high surface area of up to 2285 m2 g-1 and a thickness down to ∼4 nm can be obtained. These important characteristics make the nanocarbons demonstrate a high capacitance of 144 F g-1 at 1 A g-1 and 20 °C, and an excellent capacitance retention ratio of 64% at 100 A g-1 in ionic liquid. Because of the high fraction of meso/macropores for nanocarbons, an outstanding capacitance of 116 F g-1 can be achieved at 0 °C, with a high capacitance retention ratio of 39% at 100 A g-1. A high energy of 16-17 and 9-10 W h kg-1 can be maintained at 20 and 0 °C when the supercapacitor is charged in less than 1s. The excellent electrochemical response of nanocarbons suggests that the proposed preparation process is promising for developing advanced carbon electrodes.

  7. Efficient asymmetric hydrolysis of styrene oxide catalyzed by Mung bean epoxide hydrolases in ionic liquid-based biphasic systems.

    Science.gov (United States)

    Chen, Wen-Jing; Lou, Wen-Yong; Zong, Min-Hua

    2012-07-01

    The asymmetric hydrolysis of styrene oxide to (R)-1-phenyl-1,2-ethanediol using Mung bean epoxide hydrolases was, for the first time, successfully conducted in an ionic liquid (IL)-containing biphasic system. Compared to aqueous monophasic system, IL-based biphasic systems could not only dissolve the substrate, but also effectively inhibit the non-enzymatic hydrolysis, and therefore markedly improve the reaction efficiency. Of all the tested ILs, the best results were observed in the biphasic system containing C(4)MIM·PF(6), which exhibited good biocompatibility with the enzyme and was an excellent solvent for the substrate. In the C(4)MIM·PF(6)/buffer biphasic system, it was found that the optimal volume ratio of IL to buffer, reaction temperature, buffer pH and substrate concentration were 1/6, 35°C, 6.5 and 100 mM, respectively, under which the initial reaction rate, the yield and the product e.e. were 18.4 mM/h, 49.4% and 97.0%. The biocatalytic process was shown to be feasible on a 500-mL preparative scale. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. Ultrasonic-energy enhance the ionic liquid-based dual microextraction to preconcentrate the lead in ground and stored rain water samples as compared to conventional shaking method.

    Science.gov (United States)

    Nizamani, Sooraj; Kazi, Tasneem G; Afridi, Hassan I

    2018-01-01

    An efficient preconcentration technique based on ultrasonic-assisted ionic liquid-based dual microextraction (UA-ILDµE) method has been developed to preconcentrate the lead (Pb +2 ) in ground and stored rain water. In the current proposed method, Pb +2 was complexed with a chelating agent (dithizone), whereas an ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) was used for extraction purpose. The ultrasonic irradiation and electrical shaking system were applied to enhance the dispersion and extraction of Pb +2 complex in aqueous samples. For second phase, dual microextraction (DµE phase), the enriched Pb +2 complex in ionic liquid, extracted back into the acidic aqueous solution and finally determined by flame atomic absorption spectrometry. Some major analytical parameters that influenced the extraction efficiency of developed method, such as pH, concentration of ligand, volume of ionic liquid and samples, time of shaking in thermostatic electrical shaker and ultrasonic bath, effect of back extracting HNO 3 volume, matrix effect, centrifugation time and rate were optimized. At the sample volume of 25mL, the calculated preconcentration factor was 62.2. The limit of detection of proposed procedure for Pb +2 ions was found to be 0.54μgL -1 . The validation of developed method was performed by the analysis of certified sample of water SRM 1643e and standard addition method in a real water sample. The extraction recovery of Pb +2 was enhanced≥2% with shaking time of 80s in ultrasonic bath as compared to used thermostatic electrical shaker, where for optimum recovery up to 10min was required. The developed procedure was successfully used for the enrichment of Pb +2 in ground and stored rain water (surface water) samples of an endemic region of Pakistan. The resulted data indicated that the ground water samples were highly contaminated with Pb +2 , while some of the surface water samples were also have higher values of Pb +2 than permissible limit of

  9. Ultrasound-assisted sol-gel synthesis of ZrO2.

    Science.gov (United States)

    Guel, Marlene Lariza Andrade; Jiménez, Lourdes Díaz; Hernández, Dora Alicia Cortés

    2017-03-01

    Synthesis of tetragonal ZrO 2 by both conventional sol-gel and ultrasound-assisted sol-gel methods and using a non-ionic surfactant Tween-20, was performed. A porous microstructure composed of nanometric particles was observed. Tetragonal ZrO 2 was obtained using a low heat treatment temperature of powders, 500°C by both methods. A higher crystallinity and a shorter reaction time were observed when ultrasound was used in the sol-gel method due to the cavitation phenomenon. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Ultrasound-assisted dyeing of cellulose acetate.

    Science.gov (United States)

    Udrescu, C; Ferrero, F; Periolatto, M

    2014-07-01

    The possibility of reducing the use of auxiliaries in conventional cellulose acetate dyeing with Disperse Red 50 using ultrasound technique was studied as an alternative to the standard procedure. Dyeing of cellulose acetate yarn was carried out by using either mechanical agitation alone, with and without auxiliaries, or coupling mechanical and ultrasound agitation in the bath where the temperature range was maintained between 60 and 80 °C. The best results of dyeing kinetics were obtained with ultrasound coupled with mechanical agitation without auxiliaries (90% of bath exhaustion value at 80 °C). Hence the corresponding half dyeing times, absorption rate constants according to Cegarra-Puente modified equation and ultrasound efficiency were calculated confirming the synergic effect of sonication on the dyeing kinetics. Moreover the apparent activation energies were also evaluated and the positive effect of ultrasound added to mechanical agitation was evidenced by the lower value (48 kJ/mol) in comparison with 112 and 169 kJ/mol for mechanical stirring alone with auxiliaries and without, respectively. Finally, the fastness tests gave good values for samples dyed with ultrasound technique even without auxiliaries. Moreover color measurements on dyed yarns showed that the color yield obtained by ultrasound-assisted dyeing at 80 °C of cellulose acetate without using additional chemicals into the dye bath reached the same value yielded by mechanical agitation, but with remarkably shorter time. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Sensitive determination of estrogens in environmental waters treated with polymeric ionic liquid-based stir cake sorptive extraction and liquid chromatographic analysis.

    Science.gov (United States)

    Chen, Lei; Mei, Meng; Huang, Xiaojia; Yuan, Dongxing

    2016-05-15

    A simple, sensitive and environmentally friendly method using polymeric ionic liquid-based stir cake sorptive extraction followed by high performance liquid chromatography with diode array detection (HPLC/DAD) has been developed for efficient quantification of six selected estrogens in environmental waters. To extract trace estrogens effectively, a poly (1-ally-3-vinylimidazolium chloride-co-ethylene dimethacrylate) monolithic cake was prepared and used as the sorbent of stir cake sorptive extraction (SCSE). The effects of preparation conditions of sorbent and extraction parameters of SCSE for estrogens were investigated and optimized. Under optimal conditions, the developed method showed satisfactory analytical performance for targeted analytes. Low limits of detection (S/N=3) and quantification limits (S/N=10) were achieved within the range of 0.024-0.057 µg/L and 0.08-0.19 µg/L, respectively. Good linearity of method was obtained for analytes with the correlation coefficients (R(2)) above 0.99. At the same time, satisfactory method repeatability and reproducibility was achieved in terms of intra- and inter-day precisions, respectively. Finally, the established SCSE-HPLC/DAD method was successfully applied for the determination of estrogens in different environmental water samples. Recoveries obtained for the determination of estrogens in spiked samples ranged from 71.2% to 108%, with RSDs below 10% in all cases. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Ionic liquid-based single-drop microextraction followed by liquid chromatography-ultraviolet spectrophotometry detection to determine typical UV filters in surface water samples.

    Science.gov (United States)

    Vidal, Lorena; Chisvert, Alberto; Canals, Antonio; Salvador, Amparo

    2010-04-15

    A user-friendly and inexpensive ionic liquid-based single-drop microextraction (IL-SDME) procedure has been developed to preconcentrate trace amounts of six typical UV filters extensively used in cosmetic products (i.e., 2-hydroxy-4-methoxybenzophenone, isoamyl 4-methoxycinnamate, 3-(4'-methylbenzylidene)camphor, 2-ethylhexyl 2-cyano-3,3-diphenylacrylate, 2-ethylhexyl 4-dimethylaminobenzoate and 2-ethylhexyl 4-methoxycinnamate) from surface water samples prior to analysis by liquid chromatography-ultraviolet spectrophotometry detection (LC-UV). A two-stage multivariate optimization approach was developed by means of a Plackett-Burman design for screening and selecting the significant variables involved in the SDME procedure, which were later optimized by means of a circumscribed central composite design. The studied variables were drop volume, sample volume, agitation speed, ionic strength, extraction time and ethanol quantity. Owing to particularities, ionic liquid type and pH of the sample were optimized separately. Under optimized experimental conditions (i.e., 10 microL of 1-hexyl-3-methylimidazolium hexafluorophosphate, 20 mL of sample containing 1% (v/v) ethanol and NaCl free adjusted to pH 2, 37 min extraction time and 1300 rpm agitation speed) enrichment factors up to ca. 100-fold were obtained depending on the target analyte. The method gave good levels of repeatability with relative standard deviations varying between 2.8 and 8.8% (n=6). Limits of detection were found in the low microg L(-1) range, varying between 0.06 and 3.0 microg L(-1) depending on the target analyte. Recovery studies from different types of surface water samples collected during the winter period, which were analysed and confirmed free of all target analytes, ranged between 92 and 115%, showing that the matrix had a negligible effect upon extraction. Finally, the proposed method was applied to the analysis of different water samples (taken from two beaches, two swimming pools and a

  13. Ultrasound-Assisted Oxidative Desulfurization of Diesel

    Directory of Open Access Journals (Sweden)

    Niran K. Ibrahim

    2016-11-01

    Full Text Available Due to the dramatic environmental impact of sulfur emissions associated with the exhaust of diesel engines, last environmental regulations for ultra-low-sulfur diesel require a very deep desulfurization (up to 15 ppm, which cannot be met by the conventional hydrodesulfurization units alone. The proposed method involves a batch ultrasound-assisted oxidative desulfurization (UAODS of a previously hydrotreated diesel (containing 480 ppm sulfur so as to convert the residual sulfur-bearing compounds into their corresponding highly polar oxides, which can be eliminated easily by extraction with a certain highly polar solvent. The oxidizing system utilized was H2O2 as an oxidant, CH3COOH as a promoter, with FeSO4 as a catalyst; whereas acetonitrile was used as extractant. The major influential parameters related to UAODS process have been investigated, namely: ratio of oxidant/fuel, ratio of the promoter/oxidant, dose of catalyst, reaction temperature, and intensity of ultrasonic waves. Kinetics of the reaction has been also studied; it was observed that the UAODS of diesel fuels fitted pseudo-first-order kinetics under the best experimental conditions, whereas values of the apparent rate constant and activation energy were 0.373 min-1 and 24 KJ/mol, respectively. The oxidation treatment, in combination with ultrasonic irradiation, revealed a synergistic effect for diesel desulfurization. The experimental results showed that sulfur removal efficiency could amount to 98% at mild operating conditions (70 ○C and 1 bar. This indicates that the process is efficient and promising for the production of ultra-low-sulfur diesel fuels.

  14. Application of Ultrasound-assisted Emulsification Microextraction ...

    African Journals Online (AJOL)

    Several factors influencing the extraction efficiency, such as the nature and volume of organic solvent, extraction temperature, ionic strength and centrifugation time, were investigated and optimized. Using optimum extraction conditions a detection limit of 0.1 μg L–1 and a good linearity in a calibration range of 0.25–250 μg ...

  15. Eco-friendly ionic liquid based ultrasonic assisted selective extraction coupled with a simple liquid chromatography for the reliable determination of acrylamide in food samples.

    Science.gov (United States)

    Albishri, Hassan M; El-Hady, Deia Abd

    2014-01-01

    Acrylamide in food has drawn worldwide attention since 2002 due to its neurotoxic and carcinogenic effects. These influences brought out the dual polar and non-polar characters of acrylamide as they enabled it to dissolve in aqueous blood medium or penetrate the non-polar plasma membrane. In the current work, a simple HPLC/UV system was used to reveal that the penetration of acrylamide in non-polar phase was stronger than its dissolution in polar phase. The presence of phosphate salts in the polar phase reduced the acrylamide interaction with the non-polar phase. Furthermore, an eco-friendly and costless coupling of the HPLC/UV with ionic liquid based ultrasonic assisted extraction (ILUAE) was developed to determine the acrylamide content in food samples. ILUAE was proposed for the efficient extraction of acrylamide from bread and potato chips samples. The extracts were obtained by soaking of potato chips and bread samples in 1.5 mol L(-1) 1-butyl-3-methylimmidazolium bromide (BMIMBr) for 30.0 and 60.0 min, respectively and subsequent chromatographic separation within 12.0 min using Luna C18 column and 100% water mobile phase with 0.5 mL min(-1) under 25 °C column temperature at 250 nm. The extraction and analysis of acrylamide could be achieved within 2h. The mean extraction efficiency of acrylamide showed adequate repeatability with relative standard deviation (RSD) of 4.5%. The limit of detection and limit of quantitation were 25.0 and 80.0 ng mL(-1), respectively. The accuracy of the proposed method was tested by recovery in seven food samples giving values ranged between 90.6% and 109.8%. Therefore, the methodology was successfully validated by official guidelines, indicating its reliability to be applied to analysis of real samples, proven to be useful for its intended purpose. Moreover, it served as a simple, eco-friendly and costless alternative method over hitherto reported ones. © 2013 Elsevier B.V. All rights reserved.

  16. KINETICS OF ULTRASOUND ASSISTED EXTRACTION OF WEDELOLACTONE FROM Eclipta alba

    Directory of Open Access Journals (Sweden)

    T. W. Charpe

    Full Text Available Abstract Ultrasound assisted extraction of wedelolactone, a major coumestan present in Eclipta alba, is investigated in the present work.Various process parameters such as type of solvent, power, solvent to solid ratio and extraction temperature, which affect the extraction yield, are optimized. In the ultrasound-assisted extraction with final optimized conditions, i.e., methanol as solvent, 170 W power, 60:1 solvent to solid ratio, 50 °C temperature and 60% duty cycle, amaximum extraction yieldof 0.62 mg/g is obtained in 45 minutes. The kinetic model (Peleg's model has been used for the prediction of the yield of wedelolactone in the extract at a given time for all experimental conditions. The values of predicted yields show good agreement with the experimental data for all parameters, i.e., power, solvent to solid ratio and temperature. The extraction of wedelolactone from Eclipta alba is also carried out by conventional extraction methods, i.e., Soxhlet and batch extraction. Ultrasound-assisted extraction gives higher extraction yield in less time as compared to batch extraction (0.41 mg/g in 90 min and Soxhlet extraction(0.7 mg/g in 360 min. The ultrasound-assisted extraction of wedelolactone from Eclipta alba is an effective way of extraction with the advantages of lower time and higher extraction.

  17. The ultrasound-assisted aqueous extraction of rice bran oil.

    Science.gov (United States)

    Khoei, Maryam; Chekin, Fereshteh

    2016-03-01

    In this work, aqueous extraction of rice bran oil was done without and with ultrasound pretreatment. Key factors controlling the extraction and optimal operating conditions were identified. The highest extraction efficiency was found at pH=12, temperature of 45°C, agitation speed of 800rpm and agitation time of 15min, ultrasound treatment time of 70min and ultrasound treatment temperature of 25°C. Moreover, extraction yields were compared to ultrasound-assisted aqueous extraction and Soxhlet extraction. The results showed that the yield of rice bran oil at ultrasound-assisted aqueous extraction was close to the yield of oil extracted by hexane Soxhlet extraction. This result implied that the yield of rice bran oil was significantly influenced by ultrasound. With regard to quality, the oil extracted by ultrasound-assisted aqueous process had a lower content of free fatty acid and lower color imparting components than the hexane-extracted oil. Also, effect of parboiling of paddy on hexane and ultrasound-assisted aqueous extraction was studied. Both extraction methods gives higher percentage of oil from par boiled rice bran compared with raw rice bran. This may be due to the fact that parboiling releases the oil. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Cu(II complexes of an ionic liquid-based Schiff base [1-{2-(2-hydroxy benzylidene amino ethyl}-3-methyl­imidazolium]Pf6: Synthesis, characterization and biological activities

    Directory of Open Access Journals (Sweden)

    Saha Sanjoy

    2015-01-01

    Full Text Available Two Cu(II complexes of an ionic liquid based Schiff base 1-{2-(2-hydroxybenzylideneamino ethyl}-3-methylimidazolium hexaflurophosphate, were prepared and characterized by different analytical and spectroscopic methods such as elemental analysis, magnetic susceptibility, UV-Vis, IR, NMR and mass spectroscopy. The Schiff base ligand was found to act as a potential bidentate chelating ligand with N, O donor sites and formed 1:2 metal chelates with Cu(II salts. The synthesized Cu(II complexes were tested for biological activity.

  19. Ultrasound assisted evaluation of chest pain in the emergency department.

    Science.gov (United States)

    Colony, M Deborah; Edwards, Frank; Kellogg, Dylan

    2018-04-01

    Chest pain is a commonly encountered emergency department complaint, with a broad differential including several life-threatening possible conditions. Ultrasound-assisted evaluation can potentially be used to rapidly and accurately arrive at the correct diagnosis. We propose an organized, ultrasound assisted evaluation of the patient with chest pain using a combination of ultrasound, echocardiography and clinical parameters. Basic echo techniques which can be mastered by residents in a short time are used plus standardized clinical questions and examination. Information is kept on a checklist. We hypothesize that this will result in a quicker, more accurate evaluation of chest pain in the ED leading to timely treatment and disposition of the patient, less provider anxiety, a reduction in the number of diagnostic errors, and the removal of false assumptions from the diagnostic process. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. The ultrasound-assisted sugar extraction from sugar beet cossettes

    International Nuclear Information System (INIS)

    Stasiak, D.M.

    2005-01-01

    The aim of this work was to study the ultrasound-assisted water extraction of sugar from sugar beet cossettes. The ultrasound bath device (25 kHz, 200 W) was used. The sonication accelerated sugar diffusion at both temperatures 18 deg C and 77.6 deg C and gave the higher level of dry matter content SS (4-6 percent) and sugar content CK (7-22 percent) in juice. The SS and CK depended on time of exposition, time and temperature of extraction. In particular, the effects of 5 min ultrasound-assisted extraction were equal to 20 min extraction in traditional conditions. The shorter time, lower temperature, higher efficiency and purity of juice could be the effects of sugar extraction with ultrasound. The change of thickness of diffusion membrane, microflows in tissue as well as it's environment caused by ultrasound was the reason of acceleration of sugar extraction

  1. Ultrasound assisted extraction of polyphenols from Punica granatum (Grenada) fruit

    International Nuclear Information System (INIS)

    Rodriguez Chanfrau, Jorge Enrique; Lopez Armas, Marilyn

    2014-01-01

    Extraction of bioactive compounds from vegetable materials is a classical operation applied in many industrial processes. Few studies have made reference to processes to obtain extracts from Punica granatum. This fruit is generally consumed as such or as fermented juices. In Cuba, it is known as grenade and numerous studies have shown antiviral, antioxidant and antimicrobial properties. Maceration process is the main used technology in the preparation of extracts from Punica granatum fruit, being this a long and expensive process. Ultrasound-assisted extractions have been proven to significantly decreased extraction time and increased extraction yields in many vegetable materials. However, few papers report the use of this methodology in the extraction processes of Punica granatum. To evaluate an ultrasound-assisted extraction process to extract polyphenols from Punica granatum fruit

  2. Ultrasound-Assisted Hot Air Drying of Foods

    Science.gov (United States)

    Mulet, Antonio; Cárcel, Juan Andrés; García-Pérez, José Vicente; Riera, Enrique

    This chapter deals with the application of power ultrasound, also named high-intensity ultrasound, in the hot air drying of foods. The aim of ultrasound-assisted drying is to overcome some of the limitations of traditional convective drying systems, especially by increasing drying rate without reducing quality attributes. The effects of ultrasound on drying rate are responsible for some of the phenomena produced in the internal and/or external resistance to mass transfer.

  3. A green ionic liquid-based vortex-forced MSPD method for the simultaneous determination of 5-HMF and iridoid glycosides from Fructus Corni by ultra-high performance liquid chromatography.

    Science.gov (United States)

    Du, Kunze; Li, Jin; Bai, Yun; An, Mingrui; Gao, Xiu-Mei; Chang, Yan-Xu

    2018-04-01

    A simple and green ionic liquid-based vortex-forced matrix solid phase dispersion (IL-VFMSPD) method was presented to simultaneously extract 5-hydroxymethyl furfurol (5-HMF) and iridoid glycosides in Fructus Corni by ultra-high performance liquid chromatography. Ionic liquid was used as a green elution reagent in vortex-forced MSPD process. A few parameters such as the type of ionic liquid, the type of sorbent, ratio of sample to sorbent, the concentration and volume of ionic liquid, grinding time and vortex time, were investigated in detail and an orthogonal design experiment was introduced to confirm the best conditions in this procedure. With the final optimized method, the recoveries of the target compounds in Fructus Corni were in the range of 95.2-103% (RSD<5.0%) and the method displayed a good linearity within the range of 0.8-200 μg mL -1 for morroniside, sweroside, loganin, cornuside and 1.2-300 μg mL -1 for 5-HMF. The limits of detection ranged from 0.02 to 0.08 μg mL -1 for all compounds. The results showed that the newly established method was efficiently applied to extract and determine iridoid glycosides and 5-HMF for quality control of Fructus Corni. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Extraction and Chromatographic Determination of Shikimic Acid in Chinese Conifer Needles with 1-Benzyl-3-methylimidazolium Bromide Ionic Liquid Aqueous Solutions

    Science.gov (United States)

    Chen, Fengli; Hou, Kexin; Li, Shuangyang; Zu, Yuangang; Yang, Lei

    2014-01-01

    An ionic liquids-based ultrasound-assisted extraction (ILUAE) method was successfully developed for extracting shikimic acid from conifer needles. Eleven 1-alkyl-3-methylimidazolium ionic liquids with different cations and anions were investigated and 1-benzyl-3-methylimidazolium bromide solution was selected as the solvent. The conditions for ILUAE, including the ionic liquid concentration, ultrasound power, ultrasound time, and liquid-solid ratio, were optimized. The proposed method had good recovery (99.37%–100.11%) and reproducibility (RSD, n = 6; 3.6%). ILUAE was an efficient, rapid, and simple sample preparation technique that showed high reproducibility. Based on the results, a number of plant species, namely, Picea koraiensis, Picea meyeri, Pinus elliottii, and Pinus banksiana, were identified as among the best resources of shikimic acid. PMID:24782942

  5. Development of a robust ionic liquid-based dispersive liquid-liquid microextraction against high concentration of salt for preconcentration of trace metals in saline aqueous samples: Application to the determination of Pb and Cd

    International Nuclear Information System (INIS)

    Yousefi, Seyed Reza; Shemirani, Farzaneh

    2010-01-01

    A new ionic liquid-based dispersive liquid-liquid microextraction method was developed for preconcentration and determination of compounds in aqueous samples containing very high salt concentrations. This method can solve the problems associated with the limited application of the conventional IL-based DLLME in these samples. This is believed to arise from dissolving of the ionic liquids in aqueous samples with high salt content. In this method, the robustness of microextraction system against high salt concentration (up to 40%, w/v) is increased by introducing a common ion of the ionic liquid into the sample solution. The proposed method was applied satisfactorily to the preconcentration of lead and cadmium in saline samples. After preconcentration, the settled IL-phase was dissolved in 100 μL ethanol and aspirated into the flame atomic absorption spectrometer (FAAS) using a home-made microsample introduction system. Several variables affecting the microextraction efficiency were investigated and optimized. Under the optimized conditions and preconcentration of only 10 mL of sample, the enhancement factors of 273 and 311 and the detection limits of 0.6 μg L -1 and 0.03 μg L -1 were obtained for lead and cadmium, respectively. Validation of the method was performed by both an analysis of a certified reference material (CRM) and comparison of results with those obtained by ISO standard method.

  6. Solvation of ionic liquids based on N-alkyl-N-methylmorpholinium cations in N,N-dimethylformamide and dimethyl sulfoxide – A volumetric and acoustic study

    International Nuclear Information System (INIS)

    Marcinkowski, Łukasz; Szepiński, Emil; Kloskowski, Adam; Namieśnik, Jacek; Warmińska, Dorota

    2017-01-01

    Highlights: • V ϕ of DMSO and DMF solutions of [Mor1,R][BF 4 ] increase with increasing IL concentration at all investigated temperatures. • Ion–ion interaction are stronger for DMF solutions than corresponding for DMSO. • DMSO interacts more effectively with ionic liquids studied than DMF. • Obtained results are the consequence of the cation size of the ionic liquid. - Abstract: Apparent molar volumes and molar isentropic compressibilities for N-ethyl-N-methylmorpholinium and N-decyl-N-methylmorpholinium tetrafluoroborates in N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) have been determined from density and speed of sound measurements over the temperature range T = (298.15, 303.15, 308.15, 313.15, 318.15 and 328.15) K at experimental pressure p = 0.1 MPa. This data has been used to calculate partial molar volumes and partial molar isentropic compressibilities at infinite dilution. The partial molar expansion coefficients and their secondary derivative have been estimated as well. The obtained results indicate that dimethyl sulfoxide interacts more effectively with ionic liquids studied than N,N-dimetylformamide and ion–ion interaction are stronger for N,N-dimetylformamide solutions than corresponding in dimethyl sulfoxide. Moreover the temperature dependence of the limiting apparent molar volumes and compressibilities is a result of temperature influence on the electrostriction effect, the ordering of a bulk solvent and number solvent molecules in the nearest presence of the salt.

  7. A new dispersive liquid-liquid microextraction using ionic liquid based microemulsion coupled with cloud point extraction for determination of copper in serum and water samples.

    Science.gov (United States)

    Arain, Salma Aslam; Kazi, Tasneem Gul; Afridi, Hassan Imran; Arain, Mariam Shahzadi; Panhwar, Abdul Haleem; Khan, Naeemullah; Baig, Jameel Ahmed; Shah, Faheem

    2016-04-01

    A simple and rapid dispersive liquid-liquid microextraction procedure based on ionic liquid assisted microemulsion (IL-µE-DLLME) combined with cloud point extraction has been developed for preconcentration copper (Cu(2+)) in drinking water and serum samples of adolescent female hepatitits C (HCV) patients. In this method a ternary system was developed to form microemulsion (µE) by phase inversion method (PIM), using ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([C4mim][PF6]) and nonionic surfactant, TX-100 (as a stabilizer in aqueous media). The Ionic liquid microemulsion (IL-µE) was evaluated through visual assessment, optical light microscope and spectrophotometrically. The Cu(2+) in real water and aqueous acid digested serum samples were complexed with 8-hydroxyquinoline (oxine) and extracted into IL-µE medium. The phase separation of stable IL-µE was carried out by the micellar cloud point extraction approach. The influence of of different parameters such as pH, oxine concentration, centrifugation time and rate were investigated. At optimized experimental conditions, the limit of detection and enhancement factor were found to be 0.132 µg/L and 70 respectively, with relative standard deviation <5%. In order to validate the developed method, certified reference materials (SLRS-4 Riverine water) and human serum (Sero-M10181) were analyzed. The resulting data indicated a non-significant difference in obtained and certified values of Cu(2+). The developed procedure was successfully applied for the preconcentration and determination of trace levels of Cu(2+) in environmental and biological samples. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Influence of reaction conditions on formation of ionic liquid-based nanostructured Bi2O3 as an efficient visible-light-driven photocatalyst

    Science.gov (United States)

    Bagheri, Mozhgan; Heydari, Mojgan; Vaezi, Mohammad Reza

    2018-01-01

    In this study, nanostructured bismuth oxide was synthesized based on the chemical reaction of bismuth nitrate and NaOH in the ionic liquid 1-butyl-3-methylimidazolium chloride ([C4mim]Cl) under ultrasonic irradiation. The effect of sodium hydroxide with a different molar ratio of NaOH to bismuth in the range of 3-10 was investigated. The results of fourier-transform infrared spectroscopy (FT-IR) and X-ray powder diffraction (XRD) showed that NaOH has a critical role in the formation of pure α-Bi2O3. So, at high concentrations of NaOH (NaOH:Bi ≥ 7.5), the chloride anion from the ionic liquid cannot be entered into the crystalline structure of bismuth oxide, which resulted in the formation of pure bismuth oxide, while at lower concentrations of NaOH (NaOH:Bi ≤ 5), Bi3O4Cl was formed with a layered structure. The XRD results revealed that the synthesized α-Bi2O3 has a monoclinic structure and scanning electron microscopy (SEM) images showed that the sample consists of needle like particles with an average thickness of 50 nm. The ionic liquid has an important role in the prevention of an agglomeration of particles in the Bi2O3 sample. The photocatalytic activity of the synthesized Bi2O3 was investigated to study the degradation of malachite green dye as a model pollutant under visible light. The effects of various parameters such as the pH, concentration of the dye, and the catalyst on the degradation of malachite green were also investigated.

  9. Trace determination of volatile polycyclic aromatic hydrocarbons in natural waters by magnetic ionic liquid-based stir bar dispersive liquid microextraction.

    Science.gov (United States)

    Benedé, Juan L; Anderson, Jared L; Chisvert, Alberto

    2018-01-01

    In this work, a novel hybrid approach called stir bar dispersive liquid microextraction (SBDLME) that combines the advantages of stir bar sorptive extraction (SBSE) and dispersive liquid-liquid microextraction (DLLME) has been employed for the accurate and sensitive determination of ten polycyclic aromatic hydrocarbons (PAHs) in natural water samples. The extraction is carried out using a neodymium stir bar magnetically coated with a magnetic ionic liquid (MIL) as extraction device, in such a way that the MIL is dispersed into the solution at high stirring rates. Once the stirring is ceased, the MIL is magnetically retrieved onto the stir bar, and subsequently subjected to thermal desorption (TD) coupled to a gas chromatography-mass spectrometry (GC-MS) system. The main parameters involved in TD, as well as in the extraction step affecting the extraction efficiency (i.e., MIL amount, extraction time and ionic strength) were evaluated. Under the optimized conditions, the method was successfully validated showing good linearity, limits of detection and quantification in the low ng L -1 level, good intra- and inter-day repeatability (RSD < 13%) and good enrichment factors (18 - 717). This sensitive analytical method was applied to the determination of trace amounts of PAHs in three natural water samples (river, tap and rainwater) with satisfactory relative recovery values (84-115%), highlighting that the matrices under consideration do not affect the extraction process. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Long-chain ionic liquid based mixed hemimicelles and magnetic dispersed solid-phase extraction for the extraction of fluorescent whitening agents in paper materials.

    Science.gov (United States)

    Wang, Qing; Qiu, Bin; Chen, Xianbo; Wang, Bin; Zhang, Hui; Zhang, Xiaoyuan

    2017-06-01

    A novel mixed hemimicelles and magnetic dispersive solid-phase extraction method based on long-chain ionic liquids for the extraction of five fluorescent whitening agents was established. The factors influenced on extraction efficiency were investigated. Under the optimal conditions, namely, the pH of sample solution at 8.0, the concentration of long chain ionic liquid at 0.5 mmol/L, the amount of Fe 3 O 4 nanoparticle at 12 mg, extraction time at 10 min, pH 6.0 of methanol as eluent, and the desorption time at 1 min, satisfactory results were obtained. Wide linear ranges (0.02-10 ng/mL) and good linearity were attained (0.9997-0.9999). The intraday and interday RSDs were 2.1-8.3%. Limits of detection were 0.004-0.01 ng/mL, which were decreased by almost an order of magnitude compared to direct detection without extraction. The present method was applied to extract the fluorescent whitening agents in two kinds of paper samples, obtaining satisfactory results. All showed results illustrated that the detection sensitivity was improved and the proposed method was a good choice for the enriching and monitoring of trace fluorescent whitening agents. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. An Approach to Solid-State Electrical Double Layer Capacitors Fabricated with Graphene Oxide-Doped, Ionic Liquid-Based Solid Copolymer Electrolytes.

    Science.gov (United States)

    Fattah, N F A; Ng, H M; Mahipal, Y K; Numan, Arshid; Ramesh, S; Ramesh, K

    2016-06-06

    Solid polymer electrolyte (SPE) composed of semi-crystalline poly (vinylidene fluoride-hexafluoropropylene) [P(VdF-HFP)] copolymer, 1-ethyl-3-methylimidazolium bis (trifluoromethyl sulphonyl) imide [EMI-BTI] and graphene oxide (GO) was prepared and its performance evaluated. The effects of GO nano-filler were investigated in terms of enhancement in ionic conductivity along with the electrochemical properties of its electrical double layer capacitors (EDLC). The GO-doped SPE shows improvement in ionic conductivity compared to the P(VdF-HFP)-[EMI-BTI] SPE system due to the existence of the abundant oxygen-containing functional group in GO that assists in the improvement of the ion mobility in the polymer matrix. The complexation of the materials in the SPE is confirmed in X-ray diffraction (XRD) and thermogravimetric analysis (TGA) studies. The electrochemical performance of EDLC fabricated with GO-doped SPE is examined using cyclic voltammetry and charge-discharge techniques. The maximum specific capacitance obtained is 29.6 F∙g -1 , which is observed at a scan rate of 3 mV/s in 6 wt % GO-doped, SPE-based EDLC. It also has excellent cyclic retention as it is able keep the performance of the EDLC at 94% even after 3000 cycles. These results suggest GO doped SPE plays a significant role in energy storage application.

  12. Highly efficient extraction and selective separation of uranium (VI) from transition metals using new class of undiluted ionic liquids based on H-phosphonate anions.

    Science.gov (United States)

    Zarrougui, Ramzi; Mdimagh, Raouf; Raouafi, Nourreddine

    2018-01-15

    In this paper, we report the development of an environmental friendly process to decontaminate uranium-containing ores and nuclear wastes by using non-fluorinated ionic liquids (ILs). The main advantages of this extraction process are the absence of any organic diluent and extra extraction agents added to the organic phase. Moreover, the process is cost-effective and maybe applied as a sustainable hydrometallurgical method to recover uranium. The distribution ratio (D U ) and the extraction efficiency (%E) of uranium(VI) (UO 2 2+ ) were found to be dependent on the acidity of the aqueous phase, the extraction time, the alkyl chain length in the ILs, the concentration of the aqueous feed and molar quantity of ILs. The D U value is higher than 600 and the %E is equal to 98.6% when [HNO 3 ]=7M. The extraction reactions follows a neutral partition or ionic exchange mechanism depending on nitric acid concentration. The nature of bonding in the extracted complexes was investigated by spectroscopic techniques. The potential use of Mor 1-8 -OP for the separation of UO 2 2+ from a mixture containing transition metal ions M n+ was also examined. The UO 2 2+ ions were separated and extracted efficiently. These ILs are promising candidates for the recovery and separation of uranium. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. The physicochemical properties of a [DEME][TFSI] ionic liquid-based electrolyte and their influence on the performance of lithium–sulfur batteries

    International Nuclear Information System (INIS)

    Drvarič Talian, Sara; Bešter-Rogač, Marija; Dominko, Robert

    2017-01-01

    Electrolyte choice is an important decision on the quest for higher-energy batteries. Besides general guidelines on the required properties of an electrolyte suitable for use in lithium–sulfur batteries, the influence of more specific physicochemical properties on its characteristics is not well understood. For this purpose, binary mixtures based on the [DEME][TFSI] and dioxolane electrolyte system for lithium–sulfur batteries was investigated in this work. Selected physicochemical properties were determined for different mixtures of solvents and lithium salt concentrations. All the electrolytes prepared were also tested in the lithium–sulfur battery system. The capacity, Coulombic efficiency, overpotentials and impedance spectra were analyzed and a connection between them and the determined electrolyte properties elucidated. We show that the electrolyte's conductivity does not have a direct connection to any of the battery system properties measured. The highest specific capacities were obtained with batteries compromising 1.0 M LiTFSI and the highest ratio of dioxolane in the binary solvent mixture. On the other hand, the best Coulombic efficiencies were obtained with batteries having high ratios of ionic liquid. Resistance and overpotential are connected parameters and are a function of the ionic liquid content. None of the monitored parameters prevail, since the best electrochemical performance in terms of specific capacity and stability was obtained with the 1.0 M LiTFSI in X[DEME][TFSI] = 0.199 electrolyte.

  14. An Approach to Solid-State Electrical Double Layer Capacitors Fabricated with Graphene Oxide-Doped, Ionic Liquid-Based Solid Copolymer Electrolytes

    Directory of Open Access Journals (Sweden)

    N. F. A. Fattah

    2016-06-01

    Full Text Available Solid polymer electrolyte (SPE composed of semi-crystalline poly (vinylidene fluoride-hexafluoropropylene [P(VdF-HFP] copolymer, 1-ethyl-3-methylimidazolium bis (trifluoromethyl sulphonyl imide [EMI-BTI] and graphene oxide (GO was prepared and its performance evaluated. The effects of GO nano-filler were investigated in terms of enhancement in ionic conductivity along with the electrochemical properties of its electrical double layer capacitors (EDLC. The GO-doped SPE shows improvement in ionic conductivity compared to the P(VdF-HFP-[EMI-BTI] SPE system due to the existence of the abundant oxygen-containing functional group in GO that assists in the improvement of the ion mobility in the polymer matrix. The complexation of the materials in the SPE is confirmed in X-ray diffraction (XRD and thermogravimetric analysis (TGA studies. The electrochemical performance of EDLC fabricated with GO-doped SPE is examined using cyclic voltammetry and charge–discharge techniques. The maximum specific capacitance obtained is 29.6 F∙g−1, which is observed at a scan rate of 3 mV/s in 6 wt % GO-doped, SPE-based EDLC. It also has excellent cyclic retention as it is able keep the performance of the EDLC at 94% even after 3000 cycles. These results suggest GO doped SPE plays a significant role in energy storage application.

  15. Comparison of micellar extraction combined with ionic liquid based vortex-assisted liquid-liquid microextraction and modified quick, easy, cheap, effective, rugged, and safe method for the determination of difenoconazole in cowpea.

    Science.gov (United States)

    Chen, Xiaochu; Bian, Yanli; Liu, Fengmao; Teng, Peipei; Sun, Pan

    2017-10-06

    Two simple sample pretreatment for the determination of difenoconazole in cowpea was developed including micellar extraction combined with ionic liquid based vortex-assisted liquid-liquid microextraction (ME-IL-VALLME) prior to high performance liquid chromatography (HPLC), and modified quick, easy, cheap, effective, rugged, and safe method (QuEChERS) coupled with HPLC-MS/MS. In ME-IL-VALLME method, the target analyte was extracted by surfactant Tween 20 micellar solution, then the supernatant was diluted with 3mL water to decrease the solubility of micellar solution. Subsequently, the vortex-assisted liquid-liquid microextraction (VALLME) procedure was performed in the diluted extraction solution by using the ionic liquid of 1-hexyl-3-methylimidazolium hexafluorophosphate ([HMIM]PF 6 ) as the extraction solvent and Tween 20 as an emulsifier to enhance the dispersion of the water-immiscible ionic liquid into the aqueous phase. Parameters that affect the extraction have been investigated in both methods Under the optimum conditions, the limits of quantitation were 0.10 and 0.05mgkg -1 , respectively. And good linearity was achieved with the correlation coefficient higher than 0.9941. The relative recoveries ranged from 78.6 to 94.8% and 92.0 to 118.0% with the relative standard deviations (RSD) of 7.9-9.6% and 1.2-3.2%, respectively. Both methods were quick, simple and inexpensive. However, the ME-IL-VALLME method provides higher enrichment factor compared with conventional QuEChERS method. The ME-IL-VALLME method has a strong potential for the determination of difenoconazole in complex vegetable matrices with HPLC. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Ultrasound-Assisted Extraction of Stilbenes from Grape Canes

    Directory of Open Access Journals (Sweden)

    Zulema Piñeiro

    2016-06-01

    Full Text Available An analytical ultrasound-assisted extraction (UAE method has been optimized and validated for the rapid extraction of stilbenes from grape canes. The influence of sample pre-treatment (oven or freeze-drying and several extraction variables (solvent, sample-solvent ratio and extraction time between others on the extraction process were analyzed. The new method allowed the main stilbenes in grape canes to be extracted in just 10 min, with an extraction temperature of 75 °C and 60% ethanol in water as the extraction solvent. Validation of the extraction method was based on analytical properties. The resulting RSDs (n = 5 for interday/intraday precision were less than 10%. Furthermore, the method was successfully applied in the analysis of 20 different grape cane samples. The result showed that grape cane byproducts are potentially sources of bioactive compounds of interest for pharmaceutical and food industries.

  17. Ultrasound-Assisted Extraction of Stilbenes from Grape Canes.

    Science.gov (United States)

    Piñeiro, Zulema; Marrufo-Curtido, Almudena; Serrano, Maria Jose; Palma, Miguel

    2016-06-16

    An analytical ultrasound-assisted extraction (UAE) method has been optimized and validated for the rapid extraction of stilbenes from grape canes. The influence of sample pre-treatment (oven or freeze-drying) and several extraction variables (solvent, sample-solvent ratio and extraction time between others) on the extraction process were analyzed. The new method allowed the main stilbenes in grape canes to be extracted in just 10 min, with an extraction temperature of 75 °C and 60% ethanol in water as the extraction solvent. Validation of the extraction method was based on analytical properties. The resulting RSDs (n = 5) for interday/intraday precision were less than 10%. Furthermore, the method was successfully applied in the analysis of 20 different grape cane samples. The result showed that grape cane byproducts are potentially sources of bioactive compounds of interest for pharmaceutical and food industries.

  18. Ultrasound-assisted endoscopic partial plantar fascia release.

    Science.gov (United States)

    Ohuchi, Hiroshi; Ichikawa, Ken; Shinga, Kotaro; Hattori, Soichi; Yamada, Shin; Takahashi, Kazuhisa

    2013-01-01

    Various surgical treatment procedures for plantar fasciitis, such as open surgery, percutaneous release, and endoscopic surgery, exist. Skin trouble, nerve disturbance, infection, and persistent pain associated with prolonged recovery time are complications of open surgery. Endoscopic partial plantar fascia release offers the surgeon clear visualization of the anatomy at the surgical site. However, the primary medial portal and portal tract used for this technique have been shown to be in close proximity to the posterior tibial nerves and their branches, and there is always the risk of nerve damage by introducing the endoscope deep to the plantar fascia. By performing endoscopic partial plantar fascia release under ultrasound assistance, we could dynamically visualize the direction of the endoscope and instrument introduction, thus preventing nerve damage from inadvertent insertion deep to the fascia. Full-thickness release of the plantar fascia at the ideal position could also be confirmed under ultrasound imaging. We discuss the technique for this new procedure.

  19. Iron species determination by task-specific ionic liquid-based in situ solvent formation dispersive liquid-liquid microextraction combined with flame atomic absorption spectrometry.

    Science.gov (United States)

    Sadeghi, Susan; Ashoori, Vahid

    2017-10-01

    The task-specific ionic liquid (TSIL) of 1-ethyl-3-methylimidazolium bromide functionalized with 8-hydroxyquinoline was used as a chelating agent and extracting solvent for dispersive liquid-liquid microextraction and subsequent determination of Fe(III) by flame atomic absorption spectrometry. The in situ solvent formation of TSIL using KPF 6 provided the desired water-immiscible ionic liquid. The total Fe concentration could be determined after pre-oxidation of Fe(II) to Fe(III). Various factors affecting the proposed extraction procedure were optimized. The proposed analytical conditions were: sample pH 5, TSIL amount 0.3% (w/v), KPF 6 amount 0.15% (w/v), anti-sticking 0.1% (w/v) and salt concentration 5% (w/v). Under optimal conditions, the linear dynamic ranges for Fe(III) and total Fe were 20-80 and 20-110 ng mL -1 , respectively, with a detection limit of 6.9 ng mL -1 for Fe(III) and relative standard deviation of 2.2%. The proposed method was successfully applied to the determination of trace Fe(III) in water (underground, tap, refined water and artificial sea water) and beverage (apple, tomato, and tea) samples. The developed method offers advantages such as simplicity, ease of operation, and extraction of Fe(III) from aqueous solutions without the use of organic solvent. It was successfully applied for iron speciation in different real samples. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  20. Dicationic polymeric ionic-liquid-based magnetic material as an adsorbent for the magnetic solid-phase extraction of organophosphate pesticides and polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Jiang, Qiong; Liu, Qin; Chen, Qiliang; Zhao, Wenjie; Xiang, Guoqiang; He, Lijun; Jiang, Xiuming; Zhang, Shusheng

    2016-08-01

    Magnetic particles modified with a dicationic polymeric ionic liquid are described as a new adsorbent in magnetic solid-phase extraction. They were obtained through the copolymerization of a 1,8-di(3-vinylimidazolium)octane-based ionic liquid with vinyl-modified SiO2 @Fe3 O4 , and were characterized by FTIR spectroscopy, X-ray diffraction, and vibrating sample magnetometry. The modified magnetic particles are effective in the extraction of organophosphate pesticides and polycyclic aromatic hydrocarbons. Also, they can provide different extraction performance for the selected analytes including fenitrothion, parathion, fenthion, phoxim, phenanthrene, and fluoranthene, where the extraction efficiency is found to be in agreement with the hydrophobicity of analytes. Various factors influencing the extraction efficiency, such as, the amount of adsorbent, extraction, and desorption time, and type and volume of the desorption solvent, were optimized. Under the optimized conditions, a good linearity ranging from 1-100 μg/L is obtained for all analytes, except for parathion (2-200 μg/L), where the correlation coefficients varied from 0.9960 to 0.9998. The limits of detection are 0.2-0.8 μg/L, and intraday and interday relative standard deviations are 1.7-7.4% (n = 5) and 3.8-8.0% (n = 3), respectively. The magnetic solid-phase extraction combined with high-performance liquid chromatography can be applied for the detection of trace targets in real water samples with satisfactory relative recoveries and relative standard deviations. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Trace mercury determination in drinking and natural water samples by room temperature ionic liquid based-preconcentration and flow injection-cold vapor atomic absorption spectrometry.

    Science.gov (United States)

    Martinis, Estefanía M; Bertón, Paula; Olsina, Roberto A; Altamirano, Jorgelina C; Wuilloud, Rodolfo G

    2009-08-15

    A liquid-liquid extraction procedure (L-L) based on room temperature ionic liquid (RTIL) was developed for the preconcentration and determination of mercury in different water samples. The analyte was quantitatively extracted with 1-butyl-3-methylimidazolium hexafluorophosphate ([C(4)mim][PF(6)]) under the form of Hg-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (Hg-5-Br-PADAP) complex. A volume of 500 microl of 9.0 mol L(-1) hydrochloric acid was used to back-extract the analyte from the RTIL phase into an aqueous media prior to its analysis by flow injection-cold vapor atomic absorption spectrometry (FI-CV-AAS). A preconcentration factor of 36 was achieved upon preconcentration of 20 mL of sample. The limit of detection (LOD) obtained under the optimal conditions was 2.3ngL(-1) and the relative standard deviation (RSD) for 10 replicates at 1 microg L(-1) Hg(2+) was 2.8%, calculated with peaks height. The method was successfully applied to the determination of mercury in river, sea, mineral and tap water samples and a certified reference material (CRM).

  2. Trace mercury determination in drinking and natural water samples by room temperature ionic liquid based-preconcentration and flow injection-cold vapor atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Martinis, Estefania M.; Berton, Paula; Olsina, Roberto A.; Altamirano, Jorgelina C.; Wuilloud, Rodolfo G.

    2009-01-01

    A liquid-liquid extraction procedure (L-L) based on room temperature ionic liquid (RTIL) was developed for the preconcentration and determination of mercury in different water samples. The analyte was quantitatively extracted with 1-butyl-3-methylimidazolium hexafluorophosphate ([C 4 mim][PF 6 ]) under the form of Hg-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (Hg-5-Br-PADAP) complex. A volume of 500 μl of 9.0 mol L -1 hydrochloric acid was used to back-extract the analyte from the RTIL phase into an aqueous media prior to its analysis by flow injection-cold vapor atomic absorption spectrometry (FI-CV-AAS). A preconcentration factor of 36 was achieved upon preconcentration of 20 mL of sample. The limit of detection (LOD) obtained under the optimal conditions was 2.3 ng L -1 and the relative standard deviation (RSD) for 10 replicates at 1 μg L -1 Hg 2+ was 2.8%, calculated with peaks height. The method was successfully applied to the determination of mercury in river, sea, mineral and tap water samples and a certified reference material (CRM).

  3. Physically Gelled Room-Temperature Ionic Liquid-Based Composite Membranes for CO2/N-2 Separation: Effect of Composition and Thickness on Membrane Properties and Performance

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, PT; Voss, BA; Wiesenauer, EF; Gin, DL; Nobe, RD

    2013-07-03

    An aspartame-based, low molecular-weight organic gelator (LMOG) was used to form melt-infused and composite membranes with two different imidazolium-based room-temperature ionic liquids (RTILs) for CO2 separation from N-2. Previous work demonstrated that LMOGs can gel RTILs at low, loading levels, and this aspartame-based LMOG was selected because it has been reported to gel a large number of RTILs. The imidazolium-based RTILs were used because of their inherent good properties for CO2/light gas separations. Analysis of the resulting bulk RTIL/LMOG physical gels showed that these materials have high sol-gel transition temperatures (ca. 135 degrees C) suitable for flue gas applications. Gas permeabilities and burst pressure measurements of thick, melt infused membranes revealed a trade-off between high CO2 permeabilities and good mechanical stability as a function of the LMOG loading. Defect-free, composite membranes of the gelled RTILs were successfully fabricated by choosing an appropriate porous membrane support (hydrophobic PTFE) using a suitable coating technique (roller coating). The thicknesses of the applied composite gel layers ranged from 10.3 to 20.7 mu m, which represents an order of magnitude decrease in active layer thickness, compared to the original melt-infused gel RTIL membranes.

  4. Final Technical Report: SISGR: The Influence of Electrolyte Structure and Electrode Morphology on the Performance of Ionic-Liquid Based Supercapacitors: A Combined Experimental and Simulation Study

    Energy Technology Data Exchange (ETDEWEB)

    Bedrov, Dmitry [University of Utah

    2013-08-15

    Obtaining fundamental understanding and developing predictive modeling capabilities of electrochemical interfaces can significantly shorten the development cycles of electrical double layer capacitors (EDLCs). A notable improvement in EDLC performance has been achieved due to recent advances in understanding charge storage mechanisms, development of advanced nanostructured electrodes and electrochemically stable electrolytes. The development of new generation of EDLCs is intimately linked to that of nanostructured carbon materials which have large surface area, good adsorption/desorption properties, good electrical conductivity and are relatively inexpensive. To address these scientific challenges the efforts of an interdisciplinary team of modelers and experimentalists were combined to enhance our understanding of molecular level mechanisms controlling the performance of EDLCs comprised of room temperature ionic liquid (RTIL) electrolytes and nanostructured carbon-based electrodes and to utilize these knowledge in the design of a new generation of materials and devices for this energy storage application. Specifically our team efforts included: atomistic molecular dynamics simulations, materials science and electrode/device assembly, and synthesis and characterization of RTIL electrolytes.

  5. The Influence of Anion Shape on the Electrical Double Layer Microstructure and Capacitance of Ionic Liquids-Based Supercapacitors by Molecular Simulations

    Directory of Open Access Journals (Sweden)

    Ming Chen

    2017-02-01

    Full Text Available Room-temperature ionic liquids (RTILs are an emerging class of electrolytes for supercapacitors. In this work, we investigate the effects of different supercapacitor models and anion shape on the electrical double layers (EDLs of two different RTILs: 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonylimide ([Emim][Tf2N] and 1-ethyl-3-methylimidazolium 2-(cyanopyrrolide ([Emim][CNPyr] by molecular dynamics (MD simulation. The EDL microstructure is represented by number densities of cations and anions, and the potential drop near neutral and charged electrodes reveal that the supercapacitor model with a single electrode has the same EDL structure as the model with two opposite electrodes. Nevertheless, the employment of the one-electrode model without tuning the bulk density of RTILs is more time-saving in contrast to the two-electrode one. With the one-electrode model, our simulation demonstrated that the shapes of anions significantly imposed effects on the microstructure of EDLs. The EDL differential capacitance vs. potential (C-V curves of [Emim][CNPyr] electrolyte exhibit higher differential capacitance at positive potentials. The modeling study provides microscopic insight into the EDLs structure of RTILs with different anion shapes.

  6. Ionic liquid-based observation technique for nonconductive materials in the scanning electron microscope: Application to the characterization of a rare earth ore.

    Science.gov (United States)

    Brodusch, Nicolas; Waters, Kristian; Demers, Hendrix; Gauvin, Raynald

    2014-03-01

    A new approach for preparing geological materials is proposed to reduce charging during their characterization in a scanning electron microscope. This technique was applied to a sample of the Nechalacho rare earth deposit, which contains a significant amount of the minerals fergusonite and zircon. Instead of covering the specimen surface with a conductive coating, the sample was immersed in a dilute solution of ionic liquid and then air dried prior to SEM analysis. Imaging at a wide range of accelerating voltages was then possible without evidence of charging when using the in-chamber secondary and backscattered electrons detectors, even at 1 kV. High resolution x-ray and electron backscatter diffraction mapping were successfully obtained at 20 and 5 kV with negligible image drifting and permitted the characterization of the microstructure of the zircon/fergusonite-Y aggregates encased in the matrix minerals. Because of the absence of a conductive layer at the surface of the specimen, the Kikuchi band contrast was improved and the backscatter electron signal increased at both 5 and 20 kV as confirmed by Monte Carlo modeling. These major developments led to an improvement of the spatial resolution and efficiency of the above characterization techniques applied to the rare earth ore and it is expected that they can be applied to other types of ores and minerals. Copyright © 2014 Wiley Periodicals, Inc.

  7. Scaling-Up Ionic Liquid-Based Technologies: How Much Do We Care About Their Toxicity? Prima Facie Information on 1-Ethyl-3-Methylimidazolium Acetate.

    Science.gov (United States)

    Ostadjoo, Shaghayegh; Berton, Paula; Shamshina, Julia L; Rogers, Robin D

    2018-02-01

    The potential of the ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]) to dissolve a variety of biopolymers such as cellulose and chitin, makes it an attractive candidate for scaled-up industrial utilization. In fact, the first steps towards its use at industrial scale have been taken. This increases the urgency to fill the knowledge gaps in its toxicity and environmental impact in order to predict and control its environmental fate. In this mini-review, we discuss the available literature surrounding this key IL. The literature (through the analysis of toxicity of the anion and the cation separately) suggests that [C2mim][OAc] is a relatively safe choice for industrial applications. However, because the IL should be considered as a compound, with unique properties arising from the interactions between the ions, comprehensive toxicity information for this particular IL is still required. To decide, prima facie, if this IL is toxic or not, evaluation of its influence on human health and ecotoxicity is needed prior to its large scale utilization. We chose in this mini-review to focus on toxicity surrounding this IL and evaluate what is known and what is not. Here with all the information in hand, we hope that the urgent need for [C2mim][OAc] toxicological assessment before it can be used in numerous technologies is highlighted. In the near future, we expect that the assessment of toxicity and environmental fate and impact can be integrated directly into any research into the industrial utilization of this IL and any others contemplated for industrial application. © The Author 2017. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  8. Correlating Coating Characteristics with the Performance of Drug-Coated Balloons – A Comparative In Vitro Investigation of Own Established Hydrogel- and Ionic Liquid-Based Coating Matrices

    Science.gov (United States)

    Kaule, Sebastian; Minrath, Ingo; Stein, Florian; Kragl, Udo; Schmidt, Wolfram; Schmitz, Klaus-Peter; Sternberg, Katrin; Petersen, Svea

    2015-01-01

    Drug-coated balloons (DCB), which have emerged as a therapeutic alternative to drug-eluting stents in percutaneous cardiovascular intervention, are well described with regard to clinical efficacy and safety within a number of clinical studies. In vitro studies elucidating the correlation between coating additive and DCB performance are however rare but considered important for the understanding of DCB requirements and the improvement of established DCB. In this regard, we examined three different DCB-systems, which were developed in former studies based on the ionic liquid cetylpyridinium salicylate, the body-own hydrogel hyaluronic acid and the pharmaceutically well-established hydrogel polyvinylpyrrolidone, considering coating morphology, coating thickness, drug-loss, drug-transfer to the vessel wall, residual drug-concentration on the balloon surface and entire drug-load during simulated use in an in vitro vessel model. Moreover, we investigated particle release of the different DCB during simulated use and determined the influence of the three coatings on the mechanical behavior of the balloon catheter. We could show that coating characteristics can be indeed correlated with the performance of DCB. For instance, paclitaxel incorporation in the matrix can reduce the drug wash-off and benefit a high drug transfer. Additionally, a thin coating with a smooth surface and high but delayed solubility can reduce drug wash-off and decrease particle burden. As a result, we suggest that it is very important to characterize DCB in terms of mentioned properties in vitro in addition to their clinical efficacy in order to better understand their function and provide more data for the clinicians to improve the tool of DCB in coronary angioplasty. PMID:25734818

  9. The AHA Moment: Assessment of the Redox Stability of Ionic Liquids Based on Aromatic Heterocyclic Anions (AHAs) for Nuclear Separations and Electric Energy Storage.

    Science.gov (United States)

    Shkrob, Ilya A; Marin, Timothy W

    2015-11-19

    Because of their extended conjugated bond network, aromatic compounds generally have higher redox stability than less saturated compounds. We conjectured that ionic liquids (ILs) consisting of aromatic heterocyclic anions (AHAs) may exhibit improved radiation and electrochemical stability. Such properties are important in applications of these ILs as diluents in radionuclide separations and electrolytes in the electric energy storage devices. In this study, we systematically examine the redox chemistry of the AHAs. Three classes of these anions have been studied: (i) simple 5-atom ring AHAs, such as the pyrazolide and triazolides, (ii) AHAs containing an adjacent benzene ring, and (iii) AHAs containing electron-withdrawing groups that were introduced to reduce their basicity and interaction with metal ions. It is shown that fragmentation in the reduced and oxidized states of these AHAs does not generally occur, and the two main products, respectively, are the H atom adduct and the imidyl radical. The latter species occurs either as an N σ-radical or as an N π-radical, depending on the length of the N-N bond, and the state that is stabilized in the solid matrix is frequently different from that having the lowest energy in the gas phase. In some instances, the formation of the sandwich π-stack dimer radical anions has been observed. For trifluoromethylated anions, H adduct formation did not occur; instead, there was facile loss of fluoride from their fluorinated groups. The latter can be problematic in nuclear separations, but beneficial in batteries. Overall, our study suggests that AHA-based ILs are viable candidates for use as radiation-exposed diluents and electrolytes.

  10. Hydrogen Bonding, (1)H NMR, and Molecular Electron Density Topographical Characteristics of Ionic Liquids Based on Amino Acid Cations and Their Ester Derivatives.

    Science.gov (United States)

    Rao, Soniya S; Bejoy, Namitha Brijit; Gejji, Shridhar P

    2015-08-13

    Amino acid ionic liquids (AAILs) have attracted significant attention in the recent literature owing to their ubiquitous applications in diversifying areas of modern chemistry, materials science, and biosciences. The present work focuses on unraveling the molecular interactions underlying AAILs. Electronic structures of ion pairs consisting of amino acid cations ([AA(+)], AA = Gly, Ala, Val, Leu, Ile, Pro, Ser, Thr) and their ester substituted derivatives [AAE(+)] interacting with nitrate anion [NO3(-)] have been obtained from the dispersion corrected M06-2x density functional theory. The formation of ion pair is accompanied by the transfer of proton from quaternary nitrogen to anion facilitated via hydrogen bonding. The [Ile], [Pro], [Ser], and [Thr] and their esters reveal relatively strong inter- as well as intramolecular hydrogen-bonding interactions. Consequently, the hierarchy in binding energies of [AA][NO3] ion pairs and their ester analogues turns out to be [Gly] > [Ala] > [Ser] ∼ [Val] ∼ [Ile] > [Leu] ∼ [Thr] > [Pro]. The work underlines how the interplay of intra- as well as intermolecular hydrogen-bonding interactions in [AA]- and [AAE]-based ILs manifest in their infrared and (1)H NMR spectra. Substitution of -OCH3 functional group in [AA][NO3] ILs lowers the melting point attributed to weaker hydrogen-bonding interactions, making them suitable for room temperature applications. As opposed to gas phase structures, the presence of solvent (DMSO) does not bring about any proton transfer in the ion pairs or their ester analogues. Calculated (1)H NMR chemical shifts of the solvated structures agree well with those from experiment. Correlations of decomposition temperatures in [AA]- and [AAE]-based ILs with binding energies and electron densities at the bond critical point(s) in molecular electron density topography, have been established.

  11. Guanidinium ionic liquid-based surfactants as low cytotoxic extractants: Analytical performance in an in-situ dispersive liquid-liquid microextraction method for determining personal care products.

    Science.gov (United States)

    Pacheco-Fernández, Idaira; Pino, Verónica; Ayala, Juan H; Afonso, Ana M

    2017-05-01

    The IL-based surfactant octylguanidinium chloride (C 8 Gu-Cl) was designed and synthetized with the purpose of obtaining a less harmful surfactant: containing guanidinium as core cation and a relatively short alkyl chain. Its interfacial and aggregation behavior was evaluated through conductivity and fluorescence measurements, presenting a critical micelle concentration value of 42.5 and 44.6mmolL -1 , respectively. Cytotoxicity studies were carried out with C 8 Gu-Cl and other IL-based and conventional surfactants, specifically the analogue 1-octyl-3-methylimidazolium chloride (C 8 MIm-Cl), and other imidazolium- (C 16 MIm-Br) and pyridinium- (C 16 Py-Cl) based surfactants, together with the conventional cationic CTAB and the conventional anionic SDS. From these studies, C 8 Gu-Cl was the only one to achieve the classification of low cytotoxicity. An in situ dispersive liquid-liquid microextraction (DLLME) method based on transforming the water-soluble C 8 Gu-Cl IL-based surfactant into a water-insoluble IL microdroplet via a simple metathesis reaction was then selected as the extraction/preconcentration method for a group of 6 personal care products (PCPs) present in cosmetic samples. The method was carried out in combination with high-performance liquid chromatography (HPLC) and diode array detection (DAD). The method was properly optimized, requiring the use of only 30μL of C 8 Gu-Cl for 10mL of aqueous sample with a NaCl content of 8% (w/v) to adjust the ionic strength and pH value of 5. The metathesis reaction required the addition of the anion exchange reagent (bis[(trifluoromethyl)sulfonyl]imide - 1:1 molar ratio), followed by vortex and centrifugation, and dilution of the final microdroplet up to 60μL with acetonitrile before the injection in the HPLC-DAD system. The optimum in situ DLLME-HPLC-DAD method takes ∼10min for the extraction step and ∼22min for the chromatographic separation, with analytical features of low detection limits: down to 0.4

  12. Ionic liquid based vortex assisted liquid-liquid microextraction combined with liquid chromatography mass spectrometry for the determination of bisphenols in thermal papers with the aid of response surface methodology.

    Science.gov (United States)

    Asati, Ankita; Satyanarayana, G N V; Panchal, Smita; Thakur, Ravindra Singh; Ansari, Nasreen G; Patel, Devendra K

    2017-08-04

    A sensitive, rapid and efficient ionic liquid-based vortex assisted liquid-liquid microextraction (IL-VALLME) with Liquid Chromatography Mass spectrometry (LC-MS/MS) method is proposed for the determination of bisphenols in thermal paper. Extraction factors were systematically optimized by response surface methodology. Experimental factors showing significant effects on the analytical responses were evaluated using design of experiment. The limit of detection for Bisphenol-A (BPA) and Bisphenol-S (BPS) in thermal paper were 1.25 and 0.93μgkg -1 respectively. The dynamic linearity range for BPA was between 4 and 100μgkg -1 and the determination of coefficient (R 2 ) was 0.996. The values of the same parameters were 3-100μgkg -1 and 0.998 for BPS. The extraction recoveries of BPA and BPS in thermal paper were 101% and 99%. Percent relative standard deviation (% RSD) for matrix effect and matrix match effects were not more than 10%, for both bisphenols. The proposed method uses a statistical approach for the analysis of bisphenols in environmental samples, and is easy, rapid, requires minimum organic solvents and efficient. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Extraction and preconcentration of trace Al and Cr from vegetable samples by vortex-assisted ionic liquid-based dispersive liquid-liquid microextraction prior to atomic absorption spectrometric determination.

    Science.gov (United States)

    Altunay, Nail; Yıldırım, Emre; Gürkan, Ramazan

    2018-04-15

    In the study, a simple, and efficient microextraction approach, which is termed as vortex-assisted ionic liquid-based dispersive liquid-liquid microextraction (VA-IL-DLLME), was developed for flame atomic absorption spectrometric analysis of aluminum (Al) and chromium (Cr) in vegetables. The method is based on the formation of anionic chelate complexes of Al(III) and Cr(VI) with o-hydroxy azo dye, at pH 6.5, and then extraction of the hydrophobic ternary complexes formed in presence of cetyltrimethylammonium bromide (CTAB) into a 125 μL volume of 1-butyl-3-methylimidazolium bis(trifluorosulfonyl)imide [C 4 mim][Tf 2 N]) as extraction solvent. Under optimum conditions, the detection limits were 0.02 µg L -1 in linear working range of 0.07-100 µg L -1 for Al(III), and 0.05 µg L -1 in linear working range of 0.2-80 µg L -1 for Cr(VI). After the validation by analysis of a certified reference material (CRM), the method was successfully applied to the determination of Al and Cr in vegetables using standard addition method. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Ultrasound assisted, thermally activated persulfate oxidation of coal tar DNAPLs.

    Science.gov (United States)

    Peng, Libin; Wang, Li; Hu, Xingting; Wu, Peihui; Wang, Xueqing; Huang, Chumei; Wang, Xiangyang; Deng, Dayi

    2016-11-15

    The feasibility of ultrasound assisted, thermally activated persulfate for effective oxidation of twenty 2-6 ringed coal tar PAHs in a biphasic tar/water system and a triphasic tar/soil/water system were investigated and established. The results indicate that ultrasonic assistance, persulfate and elevated reaction temperature are all required to achieve effective oxidation of coal tar PAHs, while the heating needed can be provided by ultrasonic induced heating as well. Further kinetic analysis reveals that the oxidation of individual PAH in the biphasic tar/water system follows the first-order kinetics, and individual PAH oxidation rate is primary determined by the mass transfer coefficients, tar/water interfacial areas, the aqueous solubility of individual PAH and its concentration in coal tar. Based on the kinetic analysis and experimental results, the contributions of ultrasound, persulfate and elevated reaction temperature to PAHs oxidation were characterized, and the effects of ultrasonic intensity and oxidant dosage on PAHs oxidation efficiency were investigated. In addition, the results indicate that individual PAH degradability is closely related to its reactivity as well, and the high reactivity of 4-6 ringed PAHs substantially improves their degradability. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Ultrasound-assisted extraction of amino acids from grapes.

    Science.gov (United States)

    Carrera, Ceferino; Ruiz-Rodríguez, Ana; Palma, Miguel; Barroso, Carmelo G

    2015-01-01

    Recent cultivar techniques on vineyards can have a marked influence on the final nitrogen content of grapes, specifically individual amino acid contents. Furthermore, individual amino acid contents in grapes are related to the final aromatic composition of wines. A new ultrasound-assisted method for the extraction of amino acids from grapes has been developed. Several extraction variables, including solvent (water/ethanol mixtures), solvent pH (2-7), temperature (10-70°C), ultrasonic power (20-70%) and ultrasonic frequency (0.2-1.0s(-)(1)), were optimized to guarantee full recovery of the amino acids from grapes. An experimental design was employed to optimize the extraction parameters. The surface response methodology was used to evaluate the effects of the extraction variables. The analytical properties of the new method were established, including limit of detection (average value 1.4mmolkg(-)(1)), limit of quantification (average value 2.6mmolkg(-)(1)), repeatability (average RSD=12.9%) and reproducibility (average RSD=15.7%). Finally, the new method was applied to three cultivars of white grape throughout the ripening period. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Treatment of tanneries waste water by ultrasound assisted electrolysis process

    International Nuclear Information System (INIS)

    Farooq, R.; Ahmed, Z.; Gilani, M. A.; Durrani, M.; Mahmood, Q.; Shaukat, S. F.; Choima, N.

    2013-01-01

    The leather industry is a major producer of wastewater and solid waste containing potential water and soil contaminants. Considering the large amount and variety of chemical agents used in skin processing, the wastewaters generated by tanneries are very complex. Therefore, the development of treatment methods for these effluents is extremely necessary. In this work the electrochemical treatment of a tannery wastewater by ultrasound assisted electrochemical process, using stainless steel and lead cathode and titanium anodes was studied. Effect of ultrasound irradiation at various ultrasonic intensities 0, 40, 60 and 80% on electrochemical removal of chromium was investigated. Experiments were conducted at two pH conditions of pH 3 and 9. Significant removal of chromium was found at pH 3 and it was also noticed that by increasing ultrasonic intensities, percentage removal of chromium and sulfate also increases. The optimum removal of chromium and sulfate ions was observed at 80% ultrasonic intensity. The technique of electrolysis assisted with ultrasonic waves can be further improved and can be the future waste water treatment process for industries. (author)

  17. Ultrasound Assisted Extraction of Phenolic Compounds from Peaches and Pumpkins

    Science.gov (United States)

    Altemimi, Ammar; Watson, Dennis G.; Choudhary, Ruplal; Dasari, Mallika R.; Lightfoot, David A.

    2016-01-01

    The ultrasound-assisted extraction (UAE) method was used to optimize the extraction of phenolic compounds from pumpkins and peaches. The response surface methodology (RSM) was used to study the effects of three independent variables each with three treatments. They included extraction temperatures (30, 40 and 50°C), ultrasonic power levels (30, 50 and 70%) and extraction times (10, 20 and 30 min). The optimal conditions for extractions of total phenolics from pumpkins were inferred to be a temperature of 41.45°C, a power of 44.60% and a time of 25.67 min. However, an extraction temperature of 40.99°C, power of 56.01% and time of 25.71 min was optimal for recovery of free radical scavenging activity (measured by 1, 1-diphenyl-2-picrylhydrazyl (DPPH) reduction). The optimal conditions for peach extracts were an extraction temperature of 41.53°C, power of 43.99% and time of 27.86 min for total phenolics. However, an extraction temperature of 41.60°C, power of 44.88% and time of 27.49 min was optimal for free radical scavenging activity (judged by from DPPH reduction). Further, the UAE processes were significantly better than solvent extractions without ultrasound. By electron microscopy it was concluded that ultrasonic processing caused damage in cells for all treated samples (pumpkin, peach). However, the FTIR spectra did not show any significant changes in chemical structures caused by either ultrasonic processing or solvent extraction. PMID:26885655

  18. Ultrasound-assisted fabrication of a biocompatible magnetic hydroxyapatite.

    Science.gov (United States)

    Zhou, Gang; Song, Wei; Hou, Yongzhao; Li, Qing; Deng, Xuliang; Fan, Yubo

    2014-10-01

    This work describes the fabrication and characterization of a biocompatible magnetic hydroxyapatite (HA) using an ultrasound-assisted co-precipitation method. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and transmission electron microscopy (TEM) were used to characterize the structure and chemical composition of the produced samples. The M-H loops of synthesized materials were traced using a vibrating sample magnetometer (VSM) and the biocompatibility was evaluated by cell culture and MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Furthermore, in vivo histopathological examinations were used to evaluate the potential toxicological effects of Fe₃O₄-HA composites on kidney of SD rats injected intraperitoneally with Fe₃O₄-HA particles. The results showed that magnetic iron oxide particles first replace OH ions of HA, which are parallel to the c axis, and then enter the HA crystal lattice which produces changes in the crystal surface of HA. Chemical bond interaction was observed between PO₄³⁻ groups of HA and iron ions of Fe₃O₄. The saturation magnetization (MS ) of Fe₃O₄-HA composites was 46.36 emu/g obtained from VSM data. Cell culture and MTT assays indicated that HA could affect the growth and proliferation of HEK-293 cells. This Fe₃O₄-HA composite produced no negative effects on cell morphology, viability, and proliferation and exhibited remarkable biocompatibility. Moreover, no inflammatory cell infiltration was observed in kidney histopathology slices. Therefore, this study succeeds to develop a Fe₃O₄-HA composite as a prospective biomagnetic material for future applications. © 2013 Wiley Periodicals, Inc.

  19. Ultrasound-assisted synthesis and processing of carbon materials

    Science.gov (United States)

    Fortunato, Maria E.

    2011-12-01

    heating (˜5000 K), high pressures (˜300 atm), and enormous heating and cooling rates (>109 K/sec). In solid-liquid slurries, surface erosion and particle fracture occur due to the shockwaves and microjets formed from asymmetric bubble collapse at extended surfaces. The chemical and physical effects of ultrasound have been studied as an adjunct to the traditional chemical pretreatment of lignocellulosic biomass for ethanol production. Lignocellulosic biomass consists of cellulose, hemicellulose, and lignin. The surface effects of ultrasound were used in this work to increase the accessibility of the cellulose, which can be converted to glucose and then fermented into ethanol. The lignocellulosic biomass used in this work was Miscanthus x giganteus (Mxg) which was grown at the University of Illinois at Urbana-Champaign. The chemical effects of NaOH pretreatment on Mxg were enhanced by ultrasound: greater delignification and a significant increase in the amount of pores >5 nm were observed. ˜ 70% of the theoretical glucose yield was obtained by enzymatic saccharification of the ultrasound-assisted NaOH-pretreated Mxg; this is comparable to the yields that can be obtained by traditional alkaline pretreatments, but it was achieved in a shorter time and at a lower temperature. Because the apparatus used for laboratory studies is not a likely device for scale-up, the economics of ultrasound with regards to energy balance are not yet resolved.

  20. Development of an Ionic Liquid-Based Ultrasonic/Microwave-Assisted Simultaneous Distillation and Extraction Method for Separation of Camptothecin, 10-Hydroxycamptothecin, Vincoside-Lactam, and Essential Oils from the Fruits of Camptotheca acuminata Decne

    Directory of Open Access Journals (Sweden)

    Chunjian Zhao

    2016-10-01

    Full Text Available An ionic liquid-based ultrasonic/microwave-assisted simultaneous distillation and extraction (IL-UMASDE method for isolating camptothecin (CPT, 10-hydroxycamptothecin (HCPT, vincoside-lactam (VCS-LT, and essential oils (EOs from Camptotheca acuminata Decne fruits was developed. The important parameters were optimized using single-factor and central composite design experiments. The optimum conditions were 0.75 M 1-octyl-3-methylimidazolium ([C8mim]Br as the extraction solvent, a liquid–solid ratio of 13.7 mL/g, an extraction time of 33.2 min, a microwave power of 582 W, and a fixed ultrasonic power of 50 W. The yields of CPT, HCPT, and VCS-LT obtained under the optimum conditions were 2.463, 0.164, and 0.297 mg/g, respectively; these are 1.08-, 1.12-, and 1.04-fold higher, respectively, than those obtained by conventional 55% ethanol heat reflux extraction (HRE. The extraction time for the equilibrium yields of CPT, HCPT and VCS-LT using IL-UMASDE was 33.6%, 58.5%, 63.1%, and 66.8%, respectively, less than the corresponding times using IL-MASDE, IL-ultrasonic-assisted extraction (IL-UAE, 55% ethanol UAE and 55% ethanol HRE. The yield of EOs obtained using IL-UMASDE was 0.793 mg/g, i.e., 1.31-fold higher than that obtained by conventional hydrodistillation extraction (HDE. The components of the EOs obtained using IL-UMASDE and HDE were similar. The extraction time for the equilibrium yields of EOs using IL-UMASDE is 33.6%, 58.5%, 52.6%, and 72.3% lower than those for IL-MASDE, water-UMASDE, water-MASDE, and HDE, respectively. Compared with other extraction methods, IL-UMASDE gave the highest yields of CPT, HCPT, VCS-LT, and EOs and also had the shortest extraction time. IL-UMASDE is a potential green and highly efficient technique for the extraction of CPT, HCPT, VCS-LT, and EOs from Camptotheca acuminata Decne fruits.

  1. Ultrasound-assisted extraction of phenolic antioxidants from Acacia confusa flowers and buds.

    Science.gov (United States)

    Tung, Yu Tang; Chang, Wei Chun; Chen, Ping Sheng; Chang, Tzu Cheng; Chang, Shang Tzen

    2011-04-01

    Acacia confusa Merr. (Leguminosae), a species native to Taiwan, is widely distributed on the hills and lowlands of Taiwan, and has been used in traditional medicines. In this study, the application of ultrasound-assisted extraction was used to extract the phenolic compounds from A. confusa flowers and buds for the first time. Among the extraction methods, it can significantly enhance the contents of phenolic compounds and antioxidant activities in A. confusa flower and bud extracts using ultrasound-assisted extraction (10  min×12 times). Considering both the solvent consumption and the time needed for extraction, ultrasound-assisted extraction was found to be the most practical approach for the rapid and efficient extraction of bioactive phenolic constituents. In addition, gallic acid, myricitrin-3-rhamnoside, quercitrin-3-rhamnoside, europetin-3-rhamnoside, kaempferol-3-rhamnoside, rhamnetin-3-glucoside, and rhamnetin-3-rhamnoside were also quantified in different extracts by RP-HPLC. It is clear that ultrasound-assisted extraction is an efficient method for extracting phenolic compounds from A. confusa flowers and buds. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Classification and management of gynecomastia: defining the role of ultrasound-assisted liposuction.

    Science.gov (United States)

    Rohrich, Rod J; Ha, Richard Y; Kenkel, Jeffrey M; Adams, William P

    2003-02-01

    Gynecomastia, or excessive male breast development, has an incidence of 32 to 65 percent in the male population. This condition has important physical and psychological impacts. Advances in elucidating the pathophysiology of gynecomastia have been made, though understanding remains limited. Recommendations for evaluation and workup have varied and are often arbitrary. A diagnostic algorithm is suggested, with emphasis on a comprehensive history, physical examination, and minimizing unnecessary diagnostic testing. Medical management has had limited success; surgical therapy, primarily through excisional techniques, has been the accepted standard. Although effective, excisional techniques subject patients to large, visible scars. Ultrasound-assisted liposuction has recently emerged as a safe and effective method for the treatment of gynecomastia. It is particularly efficient in the removal of the dense, fibrous male breast tissue while offering advantages in minimal external scarring. A new system of classification and graduated treatment is proposed, based on glandular versus fibrous hypertrophy and degree of breast ptosis (skin excess). The authors' series of 61 patients with gynecomastia from 1987 to 2000 at the University of Texas Southwestern Department of Plastic Surgery demonstrated an overall success rate of 86.9 percent using suction-assisted lipectomy (1987 to 1997) and ultrasound-assisted liposuction (1997 to 2000). The authors have found ultrasound-assisted liposuction to be effective in treating most grades of gynecomastia. Excisional techniques are reserved for severe gynecomastia with significant skin excess after attempted ultrasound-assisted liposuction.

  3. Ultrasound assisted lipase catalyzed synthesis of poly-6-hydroxyhexanoate.

    Science.gov (United States)

    Gumel, A M; Annuar, M S M; Chisti, Y; Heidelberg, T

    2012-05-01

    Ultrasonic irradiation greatly improved the Candida antarctica lipase B mediated ring opening polymerization of ε-caprolactone to poly-6-hydroxyhexanoate in the ionic liquid 1-ethyl-3-methylimidazolium tetraflouroborate. Compared to the conventional nonsonicated reaction, sonication improved the monomer conversion by 63% and afforded a polymer product of a narrower molecular weight distribution and a higher degree of crystallinity. Under sonication, the polydispersity index of the product was ~1.44 compared to a value of ~2.55 for the product of the conventional reaction. With sonication, nearly 75% of the monomer was converted to product, but the conversion was only ~16% for the reaction carried out conventionally. Compared to conventional operation, sonication enhanced the rate of polymer propagation by >2-fold and the turnover number of the lipase by >3-fold. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. Ultrasound-assisted oxidative process for sulfur removal from petroleum product feedstock.

    Science.gov (United States)

    Mello, Paola de A; Duarte, Fábio A; Nunes, Matheus A G; Alencar, Mauricio S; Moreira, Elizabeth M; Korn, Mauro; Dressler, Valderi L; Flores, Erico M M

    2009-08-01

    A procedure using ultrasonic irradiation is proposed for sulfur removal of a petroleum product feedstock. The procedure involves the combination of a peroxyacid and ultrasound-assisted treatment in order to comply with the required sulfur content recommended by the current regulations for fuels. The ultrasound-assisted oxidative desulfurization (UAOD) process was applied to a petroleum product feedstock using dibenzothiophene as a model sulfur compound. The influence of ultrasonic irradiation time, oxidizing reagents amount, kind of solvent for the extraction step and kind of organic acid were investigated. The use of ultrasonic irradiation allowed higher efficiency for sulfur removal in comparison to experiments performed without its application, under the same reactional conditions. Using the optimized conditions for UAOD, the sulfur removal was about 95% after 9min of ultrasonic irradiation (20kHz, 750W, run at 40%), using hydrogen peroxide and acetic acid, followed by extraction with methanol.

  5. Synthesis of zirconium dioxide by ultrasound assisted precipitation: effect of calcination temperature.

    Science.gov (United States)

    Prasad, Krishnamurthy; Pinjari, D V; Pandit, A B; Mhaske, S T

    2011-09-01

    Nanostructured zirconium dioxide was synthesized from zirconyl nitrate using both conventional and ultrasound assisted precipitation in alkaline medium. The synthesized samples were calcinated at temperatures ranging from 400°C to 900°C in steps of 100°C. The ZrO(2) specimens were characterized using X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The thermal characteristics of the samples were studied via Differential Scanning Calorimetry-Thermo-Gravimetry Analysis (DSC-TGA). The influence of the calcination temperature on the phase transformation process from monoclinic to tetragonal to cubic zirconia and its consequent effect on the crystallite size and % crystallinity of the synthesized ZrO(2) was studied and interpreted. It was observed that the ultrasound assisted technique helped to hasten to the phase transformation and also at some point resulted in phase stabilization of the synthesized zirconia. Copyright © 2011 Elsevier B.V. All rights reserved.

  6. First investigation on ultrasound-assisted preparation of food products: sensory and physicochemical characteristics.

    Science.gov (United States)

    Pingret, Daniella; Fabiano-Tixier, Anne-Sylvie; Petitcolas, Emmanuel; Canselier, Jean-Paul; Chemat, Farid

    2011-03-01

    This paper presents a comparison between manufactured food products using conventional and ultrasound-assisted procedures. Three different foam-type products, chocolate Genoise, basic sponge cake, and chocolate mousse were prepared using both methods with subsequent evaluation of the samples using both sensory and physicochemical methods. Ultrasound-assisted preparations were considered superior according to the sensory analysis, and physicochemical data confirmed this finding. This approach of applying an emerging piece of equipment, with potential industrial application to assist food preparation, consists of a new technique that could be of great interest for the development of not only other food products created by molecular gastronomy but also for practical work carried out by students.

  7. Ultrasound-Assisted Extraction of Total Phenolic Compounds from Inula helenium

    Directory of Open Access Journals (Sweden)

    Jin Wang

    2013-01-01

    Full Text Available Ultrasound-assisted extraction (UAE of phenolic compounds from Inula helenium was studied. Effects of ethanol concentration, ultrasonic time, solid-liquid ratio, and number of extractions were investigated. An orthogonal array was constructed to optimize UAE process. The optimized extraction conditions were as follows: ethanol concentration, 30%; solid-liquid ratio, 1 : 20; number of extractions, 2 times; extraction time, 30 min. Under the optimal conditions, the yield of total phenolic compounds and chlorogenic acid was 6.13±0.58 and 1.32±0.17 mg/g, respectively. The results showed that high amounts of phenolic compounds can be extracted from I. helenium by ultrasound-assisted extraction technology.

  8. Ultrasound-Assisted Extraction of Total Flavonoids from Corn Silk and Their Antioxidant Activity

    OpenAIRE

    Zheng, Ling-Li; Wen, Guan; Yuan, Min-Yong; Gao, Feng

    2016-01-01

    Object. Ultrasound-assisted extraction of total flavonoids from corn silk and their antioxidant activities were studied. Methods. Response surface methodology was adopted to optimize the extraction conditions and antioxidant activities of the extracted total flavonoids were detected through ferric reducing antioxidant power (FRAP) assay. Results. Through a three-level, three-variable Box-Behnken design of response surface methodology (RSM) adopting yield as response, the optimal conditions we...

  9. Ultrasound assisted synthesis of iron doped TiO2 catalyst.

    Science.gov (United States)

    Ambati, Rohini; Gogate, Parag R

    2018-01-01

    The present work deals with synthesis of Fe (III) doped TiO 2 catalyst using the ultrasound assisted approach and conventional sol-gel approach with an objective of establishing the process intensification benefits. Effect of operating parameters such as Fe doping, type of solvent, solvent to precursor ratio and initial temperature has been investigated to get the best catalyst with minimum particle size. Comparison of the catalysts obtained using the conventional and ultrasound assisted approach under the optimized conditions has been performed using the characterization techniques like DLS, XRD, BET, SEM, EDS, TEM, FTIR and UV-Vis band gap analysis. It was established that catalyst synthesized by ultrasound assisted approach under optimized conditions of 0.4mol% doping, irradiation time of 60min, propan-2-ol as the solvent with the solvent to precursor ratio as 10 and initial temperature of 30°C was the best one with minimum particle size as 99nm and surface area as 49.41m 2 /g. SEM analysis, XRD analysis as well as the TEM analysis also confirmed the superiority of the catalyst obtained using ultrasound assisted approach as compared to the conventional approach. EDS analysis also confirmed the presence of 4.05mol% of Fe element in the sample of 0.4mol% iron doped TiO 2 . UV-Vis band gap results showed the reduction in band gap from 3.2eV to 2.9eV. Photocatalytic experiments performed to check the activity also confirmed that ultrasonically synthesized Fe doped TiO 2 catalyst resulted in a higher degradation of Acid Blue 80 as 38% while the conventionally synthesized catalyst resulted in a degradation of 31.1%. Overall, the work has clearly established importance of ultrasound in giving better catalyst characteristics as well as activity for degradation of the Acid Blue 80 dye. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Glucose obtained from rice bran by ultrasound-assisted enzymatic hydrolysis

    Directory of Open Access Journals (Sweden)

    Raquel Cristine Kuhn

    2015-05-01

    Full Text Available In this work ultrasound-assisted solid-state enzymatic hydrolysis of rice bran to obtain fermentable sugars was investigated. For this purpose, process variables such as temperature, enzyme concentration and moisture content were evaluated during the enzymatic hydrolysis with and without ultrasound irradiation. The enzyme used is a blend of amylases derived from genetically modified strains of Trichoderma reesei. Kinetic of the enzymatic hydrolysis of rice bran at the constant-reaction rate period were measured. The best results for the ultrasound-assisted enzymatic hydrolysis was obtained using 3 wt% of enzyme, 60 oC and moisture content of 65 wt%, yielding 0.38 g sugar/g rice bran, whereas for the hydrolysis in the absence of ultrasound the highest yield was 0.20 g sugar/g rice bran using 3 wt% of enzyme, 60 oC and moisture content of 50 wt%. The use of ultrasound-assisted enzymatic hydrolysis of rice bran was intensified, obtaining around 74% more fermentable sugar than in the absence, showing that the use of ultrasound is a promising technology to be used in enzymatic reaction as an alternative of process intensification.

  11. Ultrasound assisted extraction of food and natural products. Mechanisms, techniques, combinations, protocols and applications. A review.

    Science.gov (United States)

    Chemat, Farid; Rombaut, Natacha; Sicaire, Anne-Gaëlle; Meullemiestre, Alice; Fabiano-Tixier, Anne-Sylvie; Abert-Vian, Maryline

    2017-01-01

    This review presents a complete picture of current knowledge on ultrasound-assisted extraction (UAE) in food ingredients and products, nutraceutics, cosmetic, pharmaceutical and bioenergy applications. It provides the necessary theoretical background and some details about extraction by ultrasound, the techniques and their combinations, the mechanisms (fragmentation, erosion, capillarity, detexturation, and sonoporation), applications from laboratory to industry, security, and environmental impacts. In addition, the ultrasound extraction procedures and the important parameters influencing its performance are also included, together with the advantages and the drawbacks of each UAE techniques. Ultrasound-assisted extraction is a research topic, which affects several fields of modern plant-based chemistry. All the reported applications have shown that ultrasound-assisted extraction is a green and economically viable alternative to conventional techniques for food and natural products. The main benefits are decrease of extraction and processing time, the amount of energy and solvents used, unit operations, and CO 2 emissions. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Ionic-liquid-based dispersive liquid-liquid microextraction combined with magnetic solid-phase extraction for the determination of aflatoxins B1 , B2 , G1 , and G2 in animal feeds by high-performance liquid chromatography with fluorescence detection.

    Science.gov (United States)

    Zhao, Jiao; Zhu, Yan; Jiao, Yang; Ning, Jinyan; Yang, Yaling

    2016-10-01

    A novel two-step extraction technique combining ionic-liquid-based dispersive liquid-liquid microextraction with magnetic solid-phase extraction was developed for the preconcentration and separation of aflatoxins in animal feedstuffs before high-performance liquid chromatography coupled with fluorescence detection. In this work, ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate was used as the extractant in dispersive liquid-liquid microextraction, and hydrophobic pelargonic acid modified Fe 3 O 4 magnetic nanoparticles as an efficient adsorbent were applied to retrieve the aflatoxins-containing ionic liquid. Notably, the target of magnetic nanoparticles was the ionic liquid rather than the aflatoxins. Because of the rapid mass transfer associated with the dispersive liquid-liquid microextraction and magnetic solid phase steps, fast extraction could be achieved. The main parameters affecting the extraction recoveries of aflatoxins were investigated and optimized. Under the optimum conditions, vortexing at 2500 rpm for 1 min in the dispersive liquid-liquid microextraction and magnetic solid-phase extraction and then desorption by sonication for 2 min with acetonitrile as eluent. The recoveries were 90.3-103.7% with relative standard deviations of 3.2-6.4%. Good linearity was observed with correlation coefficients ranged from 0.9986 to 0.9995. The detection limits were 0.632, 0.087, 0.422 and 0.146 ng/mL for aflatoxins B 1 , B2, G1, and G2, respectively. The results were also compared with the pretreatment method carried out by conventional immunoaffinity columns. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Electroactive ionic liquids based on 2,5-ditert-butyl-1,4-dimethoxybenzene and triflimide anion as redox shuttle for Li4Ti5O12/LiFePO4 lithium-ion batteries

    Science.gov (United States)

    Gélinas, Bruno; Bibienne, Thomas; Dollé, Mickael; Rochefort, Dominic

    2017-12-01

    In order to increase the solubility and oxidation potential of redox shuttles, electroactive ionic liquids (RILs) based on the modification of 1,4-dimethoxybenzene with triflimide anions were synthesized. We developed two synthetic routes to obtain these RILs in which the triflimide was either linked on the benzene ring or as a ether on 2,5-ditert-butyl-1,4-dimethoxybenzene (DDB). These RILs all have melting points below 100 °C, but above room temperature. The structural impact of electroactive anion was evaluated in this study by determining the redox potential and electrochemical stability. The electrochemical properties of these RILs were investigated by cyclic voltammetry and the diffusion coefficients were measured by double potential step chronoamperometry. The viscosity and ionic conductivity measurements of redox-active electrolyte were obtained at different temperatures and the RIL additives are shown to have a low impact on these electrolyte properties at concentrations up to 0.3 M. The charge-overcharge-discharge cycles of Li/LiFePO4 half-cells and Li4Ti5O12/LiFePO4 full cells with a 100% overcharge are presented using redox-active electrolyte (0.3 M concentration level) at 0.1 C rate. This study highlights the potential of electroactive ionic liquids as highly soluble and stable functional additives in Li-ion battery electrolytes.

  14. Recent developments on ultrasound-assisted organic synthesis in aqueous medium

    Directory of Open Access Journals (Sweden)

    Banerjee Bubun

    2017-01-01

    Full Text Available In the recent past, a number of methods were reported on the application of ultrasound in organic reactions for the synthesis of diverse organic scaffolds. On the other hand, as far as green chemistry is concerned, water is the safest of all solvents. Thus, a “strong collaboration” between ultrasonic irradiation and aqueous medium holds the key to the development of an environmentally sustainable protocol. The present review summarizes the latest developments in ultrasound-assisted and water-mediated organic synthesis reported to date.

  15. Kinetics and Thermodynamics of Ultrasound-Assisted Depolymerization of κ-Carrageenan

    Directory of Open Access Journals (Sweden)

    Ratnawati Ratnawati

    2016-03-01

    Full Text Available The ultrasound-assisted depolymerization of κ-carrageenan has been studied at various temperatures and times. The κ-carrageenan with initial molecular weight of 545 kDa was dispersed in water to form a 5 g/L solution, which was then depolymerized in an ultrasound device at various temperatures and times. The viscosity of the solution was measured using Brookfield viscometer, which was then used to find the number-average molecular weight by Mark-Houwink equation. To obtain the kinetics of κ-carrageenan depolymerization, the number-average molecular weight data was treated using midpoint-chain scission kinetics model. The pre-exponential factor and activation energies for the reaction are 2.683×10-7 mol g-1 min-1 and 6.43 kJ mol-1, respectively. The limiting molecular weight varies from 160 kDa to 240 kDa, and it is linearly correlated to temperature. The results are compared to the result of thermal depolymerization by calculating the half life. It is revealed that ultrasound assisted depolymerization of κ-carrageenan is faster than thermal depolymerization at temperatures below 72.2°C. Compared to thermal depolymerization, the ultrasound-assisted process has lower values of Ea, ΔG‡, ΔH‡, and ΔS‡, which can be attributed to the ultrasonically induced breakage of non-covalent bonds in κ-carrageenan molecules. Copyright © 2016 BCREC GROUP. All rights reserved Received: 10th November 2015; Revised: 18th January 2016; Accepted: 19th January 2016 How to Cite: Ratnawati, R., Prasetyaningrum, A., Wardhani, D.H. (2016. Kinetics and Thermodynamics of Ultrasound-Assisted Depolymerization of κ-Carrageenan. Bulletin of Chemical Reaction Engineering & Catalysis, 11(1: 48-58. (doi:10.9767/bcrec.11.1.415.48-58 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.11.1.415.48-58

  16. Optimization of Ultrasound Assisted Extraction of Functional Ingredients from Stevia Rebaudiana Bertoni Leaves

    Science.gov (United States)

    Šic Žlabur, Jana; Voća, Sandra; Dobričević, Nadica; Brnčić, Mladen; Dujmić, Filip; Rimac Brnčić, Suzana

    2015-04-01

    The aim of the present study was to reveal an effective extraction procedure for maximization of the yield of steviol glycosides and total phenolic compounds as well as antioxidant activity in stevia extracts. Ultrasound assisted extraction was compared with conventional solvent extraction. The examined solvents were water (100°C/24 h) and 70% ethanol (at 70°C for 30 min). Qualitative and quantitative analyses of steviol glycosides in the extracts obtained were performed using high performance liquid chromatography. Total phenolic compounds, flavonoids, and radical scavenging capacity by 2, 2-azino-di-3-ethylbenzothialozine- sulphonic acid) assay were also determined. The highest content of steviol glycosides, total phenolic compounds, and flavonoids in stevia extracts were obtained when ultrasound assisted extraction was used. The antioxidant activity of the extracts was correlated with the total amount of phenolic compounds. The results indicated that the examined sonication parameters represented as the probe diameter (7 and 22 mm) and treatment time (2, 4, 6, 8, and 10 min) significantly contributed to the yield of steviol glycosides, total phenolic compounds, and flavonoids. The optimum conditions for the maximum yield of steviol glycosides, total phenolic compounds, and flavonoids were as follows: extraction time 10 min, probe diameter 22 mm, and temperature 81.2°C.

  17. Optimisation of ultrasound-assisted extraction of natural antioxidants from mustard seed cultivars.

    Science.gov (United States)

    Szydłowska-Czerniak, Aleksandra; Tułodziecka, Agnieszka; Karlovits, György; Szłyk, Edward

    2015-05-01

    Modified mustard varieties can produce edible oil with reduced amounts of erucic acid and glucosinolates and enhanced antioxidant potential. Therefore, this work focused on the optimisation of the ultrasound-assisted extraction of compounds with high antioxidant capacity from three white mustard seed cultivars using response surface methodology. The predicted optimum solvent polarity (57.2, 56.5 and 57.6) and ultrasound power-to-sonication time ratio (4.5, 4.8 and 4.3 W min(-1)) resulted in antioxidant capacities determined by the ferric-reducing antioxidant power (FRAP) assay [54.37, 65.75 and 68.55 mmol Trolox equivalent (TE) kg(-1)] and the 2,2'-diphenyl-1-picrylhydrazyl (DPPH) method (141.65, 175.26 and 185.10 mmol TE kg(-1)) and total phenolics content (23.70, 27.16 and 11.29 mg sinapic acid g(-1)) for extracts obtained from one traditional and two modified mustard seed varieties. The highest FRAP and DPPH values (69.51 and 197.73 mmol TE kg(-1)) revealed 50% methanolic extract prepared from modified mustard seed cultivar without erucic acid and glucosinolates treated with ultrasound for 30 min (ultrasound power/ultrasound time = 4 W min(-1)). Ultrasound-assisted extraction was found to be a more rapid, convenient and appropriate extraction method with higher yield of antioxidants, shorter time and lower solvent consumption in comparison to conventional extraction. © 2014 Society of Chemical Industry.

  18. Ultrasound-assisted oxidative desulfurization and denitrogenation of liquid hydrocarbon fuels: A critical review.

    Science.gov (United States)

    Ja'fari, Mahsa; Ebrahimi, Seyedeh Leila; Khosravi-Nikou, Mohammad Reza

    2018-01-01

    Nowadays, a continuously worldwide concern for development of process to produce ultra-low sulfur and nitrogen fuels have been emerged. Typical hydrodesulfurization and hydrodenitrogenation technology deals with important difficulties such as high pressure and temperature operating condition, failure to treat some recalcitrant compounds and limitations to meet the stringent environmental regulations. In contrary an advanced oxidation process that is ultrasound assisted oxidative desulfurization and denitrogenation satisfies latest environmental regulations in much milder conditions with more efficiency. The present work deals with a comprehensive review on findings and development in the ultrasound assisted oxidative desulfurization and denitrogenation (UAOD) during the last decades. The role of individual parameters namely temperature, residence time, ultrasound power and frequency, pH, initial concentration and types of sulfur and nitrogen compounds on the efficiency are described. What's more another treatment properties that is role of phase transfer agent (PTA) and solvents of extraction step, reaction kinetics, mechanism of the ultrasound, fuel properties and recovery in UAOD are reviewed. Finally, the required future works to mature this technology are suggested. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Optimization of biodiesel production from Chlorella protothecoides oil via ultrasound assisted transesterification

    Directory of Open Access Journals (Sweden)

    Özçimen Didem

    2017-01-01

    Full Text Available There is a growing interest in biodiesel as an alternative fuel for diesel engines because of the high oil prices and environmental issues related to massive greenhouse gas emissions. Nowadays, microalgal biomass has become a promising biodiesel feedstock. However, traditional biodiesel production from microalgae consumes a lot of energy and solvents. It is necessary to use an alternative method that can reduce the energy and alcohol consumption and save time. In this study, biodiesel production from Chlorella protothecoides oil by ultrasound assisted transesterification was conducted and effects of reaction parameters such as methanol:oil ratio, catalyst/oil ratio and reaction time on fatty acid methyl ester yields were investigated. The transesterification reactions were carried out by using methanol as alcohol and potassium hydroxide as the catalyst. The highest methyl ester production was obtained under the conditions of 9:1 methanol/oil mole ratio, 1.5% potassium hydroxide catalyst in oil, and for reaction time of 40 min. It was also found that catalyst/oil molar ratio was the most effective parameter on methyl ester yield according to statistical data. The results showed that ultrasound-assisted transesterification may be an alternative and cost effective way to produce biodiesel efficiently.

  20. Ultrasound assisted immersion freezing of broccoli (Brassica oleracea L. var. botrytis L.).

    Science.gov (United States)

    Xin, Ying; Zhang, Min; Adhikari, Benu

    2014-09-01

    The aim of this study was to research the ultrasound-assisted freezing (UAF) of broccoli. CaCl2 solution was used as freezing medium. The comparative advantage of using UAF over normal freezing on the freezing time, cell-wall bound calcium to total calcium ratio, textural properties, color, drip loss and L-ascorbic acid contents was evaluated. The application of UAF at selected acoustic intensity with a range of 0.250-0.412 W/cm(2) decreased the freezing time and the loss of cell-wall bound calcium content. Compared to normal freezing, the values of textural properties, color, L-ascorbic acid content were better preserved and the drip loss was significantly minimized by the application of UAF. However, when outside that range of acoustic intensity, the quality of the ultrasound-assisted frozen broccoli was inferior compared to that of the normally frozen samples. Selected the appropriate acoustic intensity was very important for the application of UAF. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Green ultrasound-assisted extraction of carotenoids from pomegranate wastes using vegetable oils.

    Science.gov (United States)

    Goula, Athanasia M; Ververi, Maria; Adamopoulou, Anna; Kaderides, Kyriakos

    2017-01-01

    The objective of this work was to develop a new process for pomegranate peels application in food industries based on ultrasound-assisted extraction of carotenoids using different vegetable oils as solvents. In this way, an oil enriched with antioxidants is produced. Sunflower oil and soy oil were used as alternative solvents and the effects of various parameters on extraction yield were studied. Extraction temperature, solid/oil ratio, amplitude level, and extraction time were the factors investigated with respect to extraction yield. Comparative studies between ultrasound-assisted and conventional solvent extraction were carried out in terms of processing procedure and total carotenoids content. The efficient extraction period for achieving maximum yield of pomegranate peel carotenoids was about 30min. The optimum operating conditions were found to be: extraction temperature, 51.5°C; peels/solvent ratio, 0.10; amplitude level, 58.8%; solvent, sunflower oil. A second-order kinetic model was successfully developed for describing the mechanism of ultrasound extraction under different processing parameters. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Minimizing complications of ultrasound-assisted lipoplasty: an initial experience with no related complications.

    Science.gov (United States)

    Tebbetts, J B

    1998-10-01

    Numerous complications and increased operating times were reported with ultrasonically assisted lipoplasty in the first several months after introduction of the technology in the United States. The purpose of this study was to review early reported complications and management regimens, evaluate possible causes of problems, and apply indications and techniques to attempt to minimize complications during an initial experience with this technique beginning in January of 1997. Seven specific indications and modifications of existing techniques were developed and applied to an initial clinical series of 70 consecutive patients who underwent ultrasound-assisted suction lipoplasty between January 10, 1997, and August 1, 1997. Follow-up ranged from 1 to 7 months. No perioperative or postoperative complication occurred in any patient in this series. In this series of ultrasound-assisted lipoplasty cases, application of the following criteria resulted in a series of 70 patients with 1 to 7-month follow-up without complications: (1) selecting patients with well localized fat deposits who were no more than 20 percent above their ideal body weight; (2) infusing a solution of Ringer's Lactate containing 1 cc of 1:1000 epinephrine per 1000 cc into the area of fat removal, stopping infusion when the tissues first become firm, not infusing to marked tissue turgor or skin induration; (3) restricting the level of energy application to a minimum of 1 cm from the undersurface of the dermis; (4) limiting ultrasonic energy application in each area to approximately 1 minute per estimated 100 cc of total aspirate in a wet to superwet environment; (5) not performing ultrasound-assisted lipoplasty in the same area as another procedure that could potentially compromise tissue vascularity; (6) using a Lysonix 2000 generator and 5-mm golf tee tip probe at a power setting of 8 to apply ultrasonic energy to the area of fat removal, ceasing energy application when tissue resistance to the passage

  3. A comparison of various modes of liquid-liquid based microextraction techniques: determination of picric acid.

    Science.gov (United States)

    Burdel, Martin; Šandrejová, Jana; Balogh, Ioseph S; Vishnikin, Andriy; Andruch, Vasil

    2013-03-01

    Three modes of liquid-liquid based microextraction techniques--namely auxiliary solvent-assisted dispersive liquid-liquid microextraction, auxiliary solvent-assisted dispersive liquid-liquid microextraction with low-solvent consumption, and ultrasound-assisted emulsification microextraction--were compared. Picric acid was used as the model analyte. The determination is based on the reaction of picric acid with Astra Phloxine reagent to produce an ion associate easily extractable by various organic solvents, followed by spectrophotometric detection at 558 nm. Each of the compared procedures has both advantages and disadvantages. The main benefit of ultrasound-assisted emulsification microextraction is that no hazardous chlorinated extraction solvents and no dispersive solvent are necessary. Therefore, this procedure was selected for validation. Under optimized experimental conditions (pH 3, 7 × 10(-5) mol/L of Astra Phloxine, and 100 μL of toluene), the calibration plot was linear in the range of 0.02-0.14 mg/L and the LOD was 7 μg/L of picric acid. The developed procedure was applied to the analysis of spiked water samples. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Rapid and sensitive analysis of polychlorinated biphenyls and acrylamide in food samples using ionic liquid-based in situ dispersive liquid-liquid microextraction coupled to headspace gas chromatography.

    Science.gov (United States)

    Zhang, Cheng; Cagliero, Cecilia; Pierson, Stephen A; Anderson, Jared L

    2017-01-20

    A simple and rapid ionic liquid (IL)-based in situ dispersive liquid-liquid microextraction (DLLME) method was developed and coupled to headspace gas chromatography (HS-GC) employing electron capture (ECD) and mass spectrometry (MS) detection for the analysis of polychlorinated biphenyls (PCBs) and acrylamide at trace levels from milk and coffee samples. The chemical structures of the halide-based ILs were tailored by introducing various functional groups to the cations to evaluate the effect of different structural features on the extraction efficiency of the target analytes. Extraction parameters including the molar ratio of IL to metathesis reagent and IL mass were optimized. The effects of HS oven temperature and the HS sample vial volume on the analyte response were also evaluated. The optimized in situ DLLME method exhibited good analytical precision, good linearity, and provided detection limits down to the low ppt level for PCBs and the low ppb level for acrylamide in aqueous samples. The matrix-compatibility of the developed method was also established by quantifying acrylamide in brewed coffee samples. This method is much simpler and faster compared to previously reported GC-MS methods using solid-phase microextraction (SPME) for the extraction/preconcentration of PCBs and acrylamide from complex food samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Simultaneous determination of 12 pharmaceuticals in water samples by ultrasound-assisted dispersive liquid-liquid microextraction coupled with ultra-high performance liquid chromatography with tandem mass spectrometry.

    Science.gov (United States)

    Guan, Jin; Zhang, Chi; Wang, Yang; Guo, Yiguang; Huang, Peiting; Zhao, Longshan

    2016-11-01

    A new analytical method was developed for simultaneous determination of 12 pharmaceuticals using ultrasound-assisted dispersive liquid-liquid microextraction (DLLME) followed by ultra-high performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS). Six nonsteroidal anti-inflammatory drugs (NSAIDs, ketoprofen, mefenamic acid, tolfenamic acid, naproxen, sulindac, and piroxicam) and six antibiotics (tinidazole, cefuroxime axetil, ciprofloxacin, sulfamethoxazole, sulfadiazine, and chloramphenicol) were extracted by ultrasound-assisted DLLME using dichloromethane (800 μL) and methanol/acetonitrile (1:1, v/v, 1200 μL) as the extraction and dispersive solvents, respectively. The factors affecting the extraction efficiency, such as the type and volume of extraction and dispersive solvent, vortex and ultrasonic time, sample pH, and ionic strength, were optimized. The ultrasound-assisted process was applied to accelerate the formation of the fine cloudy solution by using a small volume of dispersive solvent, which increased the extraction efficiency and reduced the equilibrium time. Under the optimal conditions, the calibration curves showed good linearity in the range of 0.04-20 ng mL -1 (ciprofloxacin and sulfadiazine), 0.2-100 ng mL -1 (ketoprofen, tinidazole, cefuroxime axetil, naproxen, sulfamethoxazole, and sulindac), and 1-200 ng mL -1 (mefenamic acid, tolfenamic acid, piroxicam, and chloramphenicol). The LODs and LOQs of the method were in the range of 0.006-0.091 and 0.018-0.281 ng mL -1 , respectively. The relative recoveries of the target analytes were in the range from 76.77 to 99.97 % with RSDs between 1.6 and 8.8 %. The developed method was successfully applied to the extraction and analysis of 12 pharmaceuticals in five kinds of water samples (drinking water, running water, river water, influent and effluent wastewater) with satisfactory results. Graphical Abstract Twelve pharmaceuticals in water samples analyted by UHPLC

  6. Ultrasound-Assisted Esterification of Valeric Acid to Alkyl Valerates Promoted by Biosilicified Lipases

    Directory of Open Access Journals (Sweden)

    Soledad Cebrián-García

    2018-06-01

    Full Text Available A novel, environmentally friendly, and sustainable ultrasound-assisted methodology in the valorization of valeric acid to alkyl valerate using a biosilicified lipase from Candida antarctica is reported. This one-pot room temperature methodology of enzyme biosilicification leads to biosilicified lipases with improved activity and reaction efficiency as compared to free enzymes. Yields in the ultrasound-promoted esterification of valeric acid was ca. 90% in 2 h with 15% m/v of biosilicified lipase (Bio-lipase; 616 U/g biocatalyst enzymatic activity and a molar ratio 1:2 (valeric acid:ethanol, slightly superior to that observed by the free enzyme (75% conversion, 583U/g biocatalyst enzymatic activity. The reuse of enzymes in these conditions was tested and the results show a relatively good reusability of these biosilicified enzymes under the investigated conditions, particularly preserving fairly stable specific activities (616 vs. 430 U/g biocatalyst after four reuses.

  7. Ultrasound assisted extraction of pectin from waste Artocarpus heterophyllus fruit peel.

    Science.gov (United States)

    Moorthy, I Ganesh; Maran, J Prakash; Ilakya, S; Anitha, S L; Sabarima, S Pooja; Priya, B

    2017-01-01

    Four factors three level face centered central composite response surface design was employed in this study to investigate and optimize the effect of process variables (liquid-solid (LS) ratio (10:1-20:1ml/g), pH (1-2), sonication time (15-30min) and extraction temperature (50-70°C)) on the maximum extraction yield of pectin from waste Artocarpus heterophyllus (Jackfruit) peel by ultrasound assisted extraction method. Numerical optimization method was adapted in this study and the following optimal condition was obtained as follows: Liquid-solid ratio of 15:1ml/g, pH of 1.6, sonication time of 24min and temperature of 60°C. The optimal condition was validated through experiments and the observed value was interrelated with predicted value. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Simultaneous determination of butyltin and phenyltin species in sediments using ultrasound-assisted leaching

    Energy Technology Data Exchange (ETDEWEB)

    Carpinteiro, J.; Rodriguez, I.; Cela, R. [Dpto. Quimica Analitica, Nutricion y Bromatologia, Universidad de Santiago de Compostela (Spain)

    2001-08-01

    A fast and simple procedure is presented for the simultaneous leaching of butyl (mono, di and tributyl) and phenyl organotin species from sediment samples. Leached compounds are further ethylated with sodium tetraethylborate in aqueous medium, and analyzed by gas chromatography. After testing the stability of triphenyltin under different extraction conditions, ultrasound-assisted leaching at room temperature in the presence of acetic acid was been proposed as an extraction procedure compatible with the simultaneous determination of phenyl- and butyltin compounds in sediments. Recoveries between 70 and 90% were obtained for phenyl species in spiked samples prepared in the laboratory. Results for butyltin species were validated by use of the reference material PACS-2. Quantification limits, using GC-MIP-AES as measurement technique, were approximately 5-10 ng g{sup -1}. Precision in the consecutive analysis of three sediment samples varied between 3 and 10%. (orig.)

  9. Ultrasound-Assisted Extraction of Total Flavonoids from Corn Silk and Their Antioxidant Activity

    Directory of Open Access Journals (Sweden)

    Ling-Li Zheng

    2016-01-01

    Full Text Available Object. Ultrasound-assisted extraction of total flavonoids from corn silk and their antioxidant activities were studied. Methods. Response surface methodology was adopted to optimize the extraction conditions and antioxidant activities of the extracted total flavonoids were detected through ferric reducing antioxidant power (FRAP assay. Results. Through a three-level, three-variable Box-Behnken design of response surface methodology (RSM adopting yield as response, the optimal conditions were determined as follows: ultrasonic power 500 W, extraction time 20 min, material solvent ratio 1 : 20, and ethanol concentration 30%. Under the optimum conditions, the extraction yield of total flavonoids was 1.13%. FRAP value of total flavonoids extracted from corn silk was 467.59 μmol/L. Conclusion. The total flavonoids of corn silk could be developed as food natural antioxidant reagents.

  10. Extraction of curcumin from Curcuma longa L. using ultrasound assisted supercritical carbon dioxide

    Science.gov (United States)

    Kimthet, Chhouk; Wahyudiono, Kanda, Hideki; Goto, Motonobu

    2017-05-01

    Curcumin is one of phenolic compounds, which has been recently shown to have useful pharmacological properties such as anti-inflammatory, anti-bacterial, anti-carcinogenic, antifungal, and antimicrobial activities. The objective of this research is to extract the curcumin from Curcuma longa L. using ultrasound assisted supercritical carbon dioxide extraction (USC-CO2). The extraction was performed at 50°C, 25 MPa, CO2 flow rate of 3 mL/min with 10% cosolvent. The result of extraction, thermogravimetry (TG), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) showed that ultrasound power could disrupt cell wall and release the target compounds from Curcuma longa L. USC-CO2 could provide higher curcumin content in the extracts and faster extraction compared to SC-CO2 extraction without ultrasound.

  11. Ultrasound assisted direct transesterification of algae for biodiesel production : Analysis of emission characteristics

    Directory of Open Access Journals (Sweden)

    Namasivayam Manickam

    2014-03-01

    Full Text Available Recently, the algae-for-fuel concept has gained renewed interest with energy prices fluctuating widely. Due to some restrictions over the oil extraction from algae, direct transesterification may be considered as a good alternative. In this study, to improve the performance of direct transesterification, ultrasound induction was carried out. A sonicator probe was used to induce the direct transesterification of Cladophora fracta, a freshwater macro alga, which contains 14% lipid on dry biomass basis. Due to ultrasonication about 25% increased biodiesel yields were obtained and the biodiesel thus prepared was analyzed for emission characteristics. The analysis results showed that Cladophora biodiesel emits 18 mg/L of CO whereas petroleum diesel emits 50 mg/L. Similarly, the emission of NOx and particulate matter also were reduced to a considerable level. The Cladophora is a suitable source of biodiesel by ultrasound assisted direct transesterification in industrial level in the future.

  12. Ultrasound-assisted powder-coating technique to improve content uniformity of low-dose solid dosage forms

    DEFF Research Database (Denmark)

    Genina, Natalja; Räikkönen, Heikki; Antikainen, Osmo

    2010-01-01

    An ultrasound-assisted powder-coating technique was used to produce a homogeneous powder formulation of a low-dose active pharmaceutical ingredient (API). The powdered particles of microcrystalline cellulose (MCC; Avicel® PH-200) were coated with a 4% m/V aqueous solution of riboflavin sodium...

  13. Decontamination of electronic waste-polluted soil by ultrasound-assisted soil washing.

    Science.gov (United States)

    Chen, Fu; Yang, Baodan; Ma, Jing; Qu, Junfeng; Liu, Gangjun

    2016-10-01

    Laboratorial scale experiments were performed to evaluate the efficacy of a washing process using the combination of methyl-β-cyclodextrin (MCD) and tea saponin (TS) for simultaneous desorption of hydrophobic organic contaminants (HOCs) and heavy metals from an electronic waste (e-waste) site. Ultrasonically aided mixing of the field contaminated soil with a combination of MCD and TS solutions simultaneously mobilizes most of polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and the analyte metal (Pb, Cu, and Ni) burdens. It is found that 15 g/L MCD and 10 g/L TS is an efficient reagent combination reconciling extraction performance and reagent costs. Under these conditions, the removal efficiencies of HOCs and heavy metals are 93.5 and 91.2 %, respectively, after 2 cycles of 60-min ultrasound-assisted washing cycles. By contrast, 86.3 % of HOCs and 88.4 % of metals are removed from the soil in the absence of ultrasound after 3 cycles of 120-min washing. The ultrasound-assisted soil washing could generate high removal efficiency and decrease the operating time significantly. Finally, the feasibility of regenerating and reusing the spent washing solution in extracting pollutants from the soil is also demonstrated. By application of this integrated technology, it is possible to recycle the washing solution for a purpose to reduce the consumption of surfactant solutions. Collectively, it has provided an effective and economic treatment of e-waste-polluted soil.

  14. Optimization of Ultrasound-assisted Extraction of Phenolic Compounds from Myrcia amazonica DC. (Myrtaceae) Leaves

    Science.gov (United States)

    de Morais Rodrigues, Mariana Cristina; Borges, Leonardo Luiz; Martins, Frederico Severino; Mourão, Rosa Helena V.; da Conceição, Edemilson Cardoso

    2016-01-01

    Background: Myrcia amazonica. DC is a species predominantly found in northern Brazil, and belongs to the Myrtaceae family, which possess various species used in folk medicine to treat gastrointestinal disorders, infectious diseases, and hemorrhagic conditions and are known for their essential oil contents. Materials and Methods: This study aimed applied the Box–Behnken design combined with response surface methodology to optimize ultrasound-assisted extraction of total polyphenols, total tannins (TT), and total flavonoids (TF) from M. amazonica DC. Results: The results indicated that the best conditions to obtain highest yields of TT were in lower levels of alcohol degree (65%), time (15 min), and also solid: Liquid ratio (solid to liquid ratio; 20 mg: 5 mL). The TF could be extracted with high amounts with higher extraction times (45 min), lower values of solid: Liquid ratio (20 mg: mL), and intermediate alcohol degree level. Conclusion: The exploitation of the natural plant resources present very important impact for the economic development, and also the valorization of great Brazilian biodiversity. The knowledge obtained from this work should be useful to further exploit and apply this raw material. SUMMARY Myrcia amazonica leaves possess phenolic compounds with biological applications;Lower levels of ethanolic strength are more suitable to obtain a igher levels of phenolic compouds such as tannins;Box-Behnken design indicates to be useful to explore the best conditions of ultrasound assisted extraction. Abbreviation used: Nomenclature ES: Ethanolic strength, ET: Extraction time, SLR: Solid to liquid ratio, TFc: Total flavonoid contents, TPc: Total polyphenol contents, TTc: Total tannin contents PMID:27019555

  15. Experimental analysis and modeling of ultrasound assisted freezing of potato spheres.

    Science.gov (United States)

    Kiani, Hossein; Zhang, Zhihang; Sun, Da-Wen

    2015-09-01

    In recent years, innovative methods such as ultrasound assisted freezing have been developed in order to improve the freezing process. During freezing of foods, accurate prediction of the temperature distribution, phase ratios, and process time is very important. In the present study, ultrasound assisted immersion freezing process (in 1:1 ethylene glycol-water solution at 253.15K) of potato spheres (0.02 m diameter) was evaluated using experimental, numerical and analytical approaches. Ultrasound (25 kHz, 890 W m(-2)) was irradiated for different duty cycles (DCs=0-100%). A finite volume based enthalpy method was used in the numerical model, based on which temperature and liquid fraction profiles were simulated by a program developed using OpenFOAM® CFD software. An analytical technique was also employed to calculate freezing times. The results showed that ultrasound irradiation could decrease the characteristic freezing time of potatoes. Since ultrasound irradiation increased the heat transfer coefficient but simultaneously generated heat at the surface of the samples, an optimum DC was needed for the shortest freezing time which occurred in the range of 30-70% DC. DCs higher than 70% increased the freezing time. DCs lower than 30% did not provide significant effects on the freezing time compared to the control sample. The numerical model predicted the characteristic freezing time in accordance with the experimental results. In addition, analytical calculation of characteristic freezing time exhibited qualitative agreement with the experimental results. As the numerical simulations provided profiles of temperature and water fraction within potatoes frozen with or without ultrasound, the models can be used to study and control different operation situations, and to improve the understanding of the freezing process. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Utilization of highly robust and selective crosslinked polymeric ionic liquid-based sorbent coatings in direct-immersion solid-phase microextraction and high-performance liquid chromatography for determining polar organic pollutants in waters.

    Science.gov (United States)

    Pacheco-Fernández, Idaira; Najafi, Ali; Pino, Verónica; Anderson, Jared L; Ayala, Juan H; Afonso, Ana M

    2016-09-01

    Several crosslinked polymeric ionic liquid (PIL)-based sorbent coatings of different nature were prepared by UV polymerization onto nitinol wires. They were evaluated in a direct-immersion solid-phase microextraction (DI-SPME) method in combination with high-performance liquid chromatography (HPLC) and diode array detection (DAD). The studied PIL coatings contained either vinyl alkyl or vinylbenzyl imidazolium-based (ViCnIm- or ViBCnIm-) IL monomers with different anions, as well as different dicationic IL crosslinkers. The analytical performance of these PIL-based SPME coatings was firstly evaluated for the extraction of a group of 10 different model analytes, including hydrocarbons and phenols, while exhaustively comparing the performance with commercial SPME fibers such as polydimethylsyloxane (PDMS), polyacrylate (PA) and polydimethylsiloxane/divinylbenzene (PDMS/DVB), and using all fibers under optimized conditions. Those fibers exhibiting a high selectivity for polar compounds were selected to carry out an analytical method for a group of 5 alkylphenols, including bisphenol-A (BPA) and nonylphenol (n-NP). Under optimum conditions, average relative recoveries of 108% and inter-day precision values (3 non-consecutive days) lower than 19% were obtained for a spiked level of 10µgL(-1). Correlations coefficients for the overall method ranged between 0.990 and 0.999, and limits of detection were down to 1µgL(-1). Tap water, river water, and bottled water were analyzed to evaluate matrix effects. Comparison with the PA fiber was also performed in terms of analytical performance. Partition coefficients (logKfs) of the alkylphenols to the SPME coating varied from 1.69 to 2.45 for the most efficient PIL-based fiber, and from 1.58 to 2.30 for the PA fiber. These results agree with those obtained by the normalized calibration slopes, pointing out the affinity of these PILs-based coatings. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Double salts of ionic-liquid-based surfactants in microextraction: application of their mixed hemimicelles as novel sorbents in magnetic-assisted micro-dispersive solid-phase extraction for the determination of phenols.

    Science.gov (United States)

    Trujillo-Rodríguez, María J; Pino, Verónica; Anderson, Jared L; Ayala, Juan H; Afonso, Ana M

    2015-11-01

    The use of mixed hemimicelles of ionic liquid (IL)-based surfactants in a magnetic-based micro-dispersive solid-phase extraction (m-μdSPE) approach is described. Not only is the symmetric monocationic IL-based surfactant 1,3-didodecylimidazolium bromide (C12C12Im-Br) studied for first time in m-μdSPE, but double-salt (DS) IL (DSIL)-based surfactants are also examined. Nine DSIL-based surfactants were formed by combination of C12C12Im-Br with other IL-based surfactants, including nonsymmetric monocationic and dicationic ILs combined at three different molar fractions. The analytical application was focused on the determination of a group of eight phenols, including bisphenol A, in water samples. The best results were obtained with the DSIL formed by C12C12Im-Br (molar fraction 0.5) and 1-hexadecyl-3-methylimidazolium bromide (C16MIm-Br), after proper optimization of the overall method in combination with high-performance liquid chromatography (HPLC) and diode-array detection (DAD). The optimum conditions for 100 mL of water samples require a small amount (10 mg) of Fe3O4 magnetic nanoparticles, a low content (5.0 mg of C12C12Im-Br and 3.9 mg of C16MIm-Br) of the selected DSIL, pH 11, a sonication time of 2.5 min, and an equilibration time of 5 min with the aid of NdFeB magnets, followed by elution of phenols, evaporation, and reconstitution with 0.5 mL of acetonitrile. The overall m-μdSPE-HPLC-DAD method is characterized for limits of detection down to 1.3 μg · L(-1), intraday relative standard deviations lower than 13 % (n = 3), and interday relative standard deviations lower than 17 % (n = 9), with a spiking level of 15 μg · L(-1); with enrichment factors between 15.7 and 141, and average relative recoveries of 99.9 %.

  18. Application of ultrasound-assisted emulsification microextraction for simultaneous determination of aminophenol isomers in human urine, hair dye, and water samples using high-performance liquid chromatography.

    Science.gov (United States)

    Asghari, Alireza; Fazl-Karimi, Hamidreza; Barfi, Behruz; Rajabi, Maryam; Daneshfar, Ali

    2014-08-01

    Aminophenol isomers (2-, 3-, and 4-aminophenols) are typically classified as industrial pollutants with genotoxic and mutagenic effects due to their easy penetration through the skin and membranes of human, animals, and plants. In the present study, a simple and efficient ultrasound-assisted emulsification microextraction procedure coupled with high-performance liquid chromatography with ultraviolet detector was developed for preconcentration and determination of these compounds in human fluid and environmental water samples. Effective parameters (such as type and volume of extraction solvent, pH and ionic strength of sample, and ultrasonication and centrifuging time) were investigated and optimized. Under optimum conditions (including sample volume: 5 mL; extraction solvent: chloroform, 80 µL; pH: 6.5; without salt addition; ultrasonication: 3.5 min; and centrifuging time: 3 min, 5000 rpm min(-1)), the enrichment factors and limits of detection were ranged from 42 to 51 and 0.028 to 0.112 µg mL(-1), respectively. Once optimized, analytical performance of the method was studied in terms of linearity (0.085-157 µg mL(-1), r (2) > 0.998), accuracy (recovery = 88.6- 101.7%), and precision (repeatability: intraday precision water samples. © The Author(s) 2014.

  19. Ionic liquids as electrolytes

    International Nuclear Information System (INIS)

    Galinski, Maciej; Lewandowski, Andrzej; Stepniak, Izabela

    2006-01-01

    Salts having a low melting point are liquid at room temperature, or even below, and form a new class of liquids usually called room temperature ionic liquids (RTIL). Information about RTILs can be found in the literature with such key words as: room temperature molten salt, low-temperature molten salt, ambient-temperature molten salt, liquid organic salt or simply ionic liquid. Their physicochemical properties are the same as high temperature ionic liquids, but the practical aspects of their maintenance or handling are different enough to merit a distinction. The class of ionic liquids, based on tetraalkylammonium cation and chloroaluminate anion, has been extensively studied since late 1970s of the XX century, following the works of Osteryoung. Systematic research on the application of chloroaluminate ionic liquids as solvents was performed in 1980s. However, ionic liquids based on aluminium halides are moisture sensitive. During the last decade an increasing number of new ionic liquids have been prepared and used as solvents. The general aim of this paper was to review the physical and chemical properties of RTILs from the point of view of their possible application as electrolytes in electrochemical processes and devices. The following points are discussed: melting and freezing, conductivity, viscosity, temperature dependence of conductivity, transport and transference numbers, electrochemical stability, possible application in aluminium electroplating, lithium batteries and in electrochemical capacitors

  20. Ultrasound assisted synthesis of Mn3O4 nanoparticles anchored graphene nanosheets for supercapacitor applications

    International Nuclear Information System (INIS)

    Raj, Balasubramaniam Gnana Sundara; Ramprasad, Rajasekharan Nair Radhika; Asiri, Abdullah M.; Wu, Jerry J; Anandan, Sambandam

    2015-01-01

    Highlights: • Room temperature synthesis of Mn 3 O 4 –graphene (MG) composite via ultra sound assisted method. • TEM images shows Mn 3 O 4 nanoparticles are uniformly distributed on the surface of graphene nanosheets. • MG composite exhibited high specific capacitance of 312 F g −1 in 1 M Na 2 SO 4 which was three times greater than pristine Mn 3 O 4 . • 76% of the initial capacitance was retained even after 1000 cycles. • The higher specific capacitance of the MG nanocomposite due to the synergistic effect between the Mn 3 O 4 nanoparticles and graphene nanosheets. - Abstract: Mn 3 O 4 nanoparticles anchored graphene nanosheets (MG) have been successfully synthesized by a simple ultrasound assisted synthesis at room temperature without the use of any templates or surfactants for supercapacitor applications. Upon ultrasound assisted synthesis, the formation of Mn 3 O 4 nanoparticles and the graphene oxide reduction occurs simultaneously. The crystalline structure of thus prepared MG nanocomposite have been characterized by the powder X-ray diffraction (XRD) analysis. Thermo Gravimetric Analysis (TGA) is used to determine the mass content of graphene (17 wt%) in the MG nanocomposite. Transmission electron microscopy (TEM) and Atomic force microscopy (AFM) studies shows that the Mn 3 O 4 nanoparticles (4–8 nm) were uniformly anchored on the surface of graphene nanosheets. The electrochemical properties of the MG nanocomposite were investigated by employing cyclic voltammetry (CV), galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS). The capacitive properties of MG nanocomposite studied in the presence of 1 M Na 2 SO 4 exhibited high specific capacitance of 312 F g −1 which was approximately three times greater than that of pristine Mn 3 O 4 (113 F g −1 ) at the same current density of 0.5 mA cm −2 in the potential range from -0.1 to +0.9 V. About 76% of the initial capacitance was retained even after 1000 cycles

  1. Ionic liquids in chemical engineering.

    Science.gov (United States)

    Werner, Sebastian; Haumann, Marco; Wasserscheid, Peter

    2010-01-01

    The development of engineering applications with ionic liquids stretches back to the mid-1990s when the first examples of continuous catalytic processes using ionic liquids and the first studies of ionic liquid-based extractions were published. Ever since, the use of ionic liquids has seen tremendous progress in many fields of chemistry and engineering, and the first commercial applications have been reported. The main driver for ionic liquid engineering applications is to make practical use of their unique property profiles, which are the result of a complex interplay of coulombic, hydrogen bonding and van der Waals interactions. Remarkably, many ionic liquid properties can be tuned in a wide range by structural modifications at their cation and anion. This review highlights specific examples of ionic liquid applications in catalysis and in separation technologies. Additionally, the application of ionic liquids as working fluids in process machines is introduced.

  2. Box-Behnken design based statistical modeling for ultrasound-assisted extraction of corn silk polysaccharide.

    Science.gov (United States)

    Prakash Maran, J; Manikandan, S; Thirugnanasambandham, K; Vigna Nivetha, C; Dinesh, R

    2013-01-30

    In this study, ultrasound assisted extraction (UAE) conditions on the yield of polysaccharide from corn silk were studied using three factors, three level Box-Behnken response surface design. Process parameters, which affect the efficiency of UAE such as extraction temperature (40-60 °C), time (10-30 min) and solid-liquid ratio (1:10-1:30 g/ml) were investigated. The results showed that, the extraction conditions have significant effects on extraction yield of polysaccharide. The obtained experimental data were fitted to a second-order polynomial equation using multiple regression analysis with high coefficient of determination value (R(2)) of 0.994. An optimization study using Derringer's desired function methodology was performed and the optimal conditions based on both individual and combinations of all independent variables (extraction temperature of 56 °C, time of 17 min and solid-liquid ratio of 1:20 g/ml) were determined with maximum polysaccharide yield of 6.06%, which was confirmed through validation experiments. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Ultrasound assisted nucleation and growth characteristics of glycine polymorphs--a combined experimental and analytical approach.

    Science.gov (United States)

    Renuka Devi, K; Raja, A; Srinivasan, K

    2015-05-01

    For the first time, the effect of ultrasound in the diagnostic frequency range of 1-10 MHz on the nucleation and growth characteristics of glycine has been explored. The investigation employing the ultrasonic interferometer was carried out at a constant insonation time over a wide range of relative supersaturation from σ=-0.09 to 0.76 in the solution. Ultrasound promotes only α nucleation and completely inhibits both the β and γ nucleation in the system. The propagation of ultrasound assisted mass transport facilitates nucleation even at very low supersaturation levels in the solution. The presence of ultrasound exhibits a profound effect on nucleation and growth characteristics in terms of decrease in induction period, increase in nucleation rate and decrease in crystal size than its absence in the solution. With an increase in the frequency of ultrasound, a further decrease in induction period, increase in nucleation rate and decrease in the size of the crystal is noticed even at the same relative supersaturation levels. The increase in the nucleation rate explains the combined dominating effects of both the ultrasound frequency and the supersaturation in the solution. Analytically, the nucleation parameters of the nucleated polymorph have been deduced at different ultrasonic frequencies based on the classical nucleation theory and correlations with the experimental results have been obtained. Structural affirmation of the nucleated polymorph has been ascertained by powder X-ray diffraction. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Value of Duplex Ultrasound Assistance for Thromboaspiration and Dilation of Thrombosed Native Arterio-Venous Fistulae

    International Nuclear Information System (INIS)

    García-Medina, J.

    2013-01-01

    Purpose: To evaluate the value of duplex ultrasound assistance during thromboaspiration of thrombosed arteriovenous fistulae for haemodialysis. Materials and Methods: We prospectively studied 54 thrombosed native fistulae (23 with total thrombosis and 31 with partial thrombosis), in which we performed manual thromboaspiration guided by ultrasonography associated with fluoroscopy. Results: The fistulae were located in the forearm (n = 39) or in the upper arm (n = 15) of 46 patients. Mean patient age was 65 years, and hypertension was the most common risk factor (74 %). Mean access age was 928 days (range 69–2,290), and most fistulae were on the left side (41 cases, 75.92 %). The success rate was 83 % in the total thrombosis group and 100 % in the partial thrombosis group. Including initial failures, the respective primary patency rates in the total thrombosis group and the partial thrombosis group were, respectively, 83 ± 8 % (n = 20) and 87 ± 6 % (n = 28) at 1 month, 39 ± 10 % (n = 10) and 61 ± 8 % (n = 20) at 6 months, and 17 ± 8 % (n = 5) and 26 ± 8 % (n = 9) at 1 year. The mean decrease of fluoroscopy time with ultrasound was 3 min (range 1–5). The mean decrease of radiation dose was 2.6 Gy cm² (range 0.9–4.3]. Conclusion: Ultrasound is a feasible and useful tool in the management of thrombosed native fistulae, thus decreasing radiation exposure, and has no detrimental effect on success rates

  5. Ultrasound-assisted enzymatic extraction and antioxidant activity of polysaccharides from pumpkin (Cucurbita moschata).

    Science.gov (United States)

    Wu, Hao; Zhu, Junxiang; Diao, Wenchao; Wang, Chengrong

    2014-11-26

    An efficient ultrasound-assisted enzymatic extraction (UAEE) of Cucurbita moschata polysaccharides (CMCP) was established and the CMCP antioxidant activities were studied. The UAEE operating parameters (extraction temperature, ultrasonic power, pH, and liquid-to-material ratio) were optimized using the central composite design (CCD) and the mass transfer kinetic study in UAEE procedure was used to select the optimal extraction time. Enzymolysis and ultrasonication that were simultaneously conducted was selected as the UAEE synergistic model and the optimum extraction conditions with a maximum polysaccharide yield of 4.33 ± 0.15% were as follows: extraction temperature, 51.5 °C; ultrasonic power, 440 W; pH, 5.0; liquid-to-material ratio, 5.70:1 mL/g; and extraction time, 20 min. Evaluation of the antioxidant activity in vitro suggested that CMCP has good potential as a natural antioxidant used in the food or medicine industry because of their high reducing power and positive radical scavenging activity for DPPH radical. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Ultrasound-assisted extraction method for the simultaneous determination of emerging contaminants in freshwater sediments.

    Science.gov (United States)

    de Sousa, Diana Nara Ribeiro; Grosseli, Guilherme Martins; Mozeto, Antonio Aparecido; Carneiro, Renato Lajarim; Fadini, Pedro Sergio

    2015-10-01

    Sediments are the fate of several emerging organic contaminants, such as pharmaceuticals, personal care products and hormones, and therefore an important subject in environmental monitoring studies. In the present work, a simple and sensitive method was developed, validated and applied for the simultaneous extraction of atenolol, caffeine, carbamazepine, diclofenac, ibuprofen, naproxen, propranolol, triclosan, estrone, 17-β-estradiol and 17-α-ethinylestradiol using ultrasound-assisted extraction from freshwater sediment samples followed by solid-phase extraction clean-up and liquid chromatography with tandem mass spectrometry detection. The solvent type and extraction pH were evaluated to obtain the highest recoveries of the compounds. The best method shows absolute recoveries between 54.0 and 94.4% at 50 ng/g concentration. The method exhibits good precision with relative standard deviation ranging from 1.0-16%. The detection and quantification limits ranged from 0.006-0.067 and 0.016-0.336 ng/g, respectively. The developed method was successfully applied to freshwater sediment samples collected from different sites in Jundiaí River basin of São Paulo State, Brazil. The compounds atenolol, caffeine, propranolol and triclosan were detected in all the sampling sites with concentrations of 13.8, 41.0, 28.5 and 176 ng/g, respectively. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Ultrasound-assisted liposuction provides a source for functional adipose-derived stromal cells.

    Science.gov (United States)

    Duscher, Dominik; Maan, Zeshaan N; Luan, Anna; Aitzetmüller, Matthias M; Brett, Elizabeth A; Atashroo, David; Whittam, Alexander J; Hu, Michael S; Walmsley, Graham G; Houschyar, Khosrow S; Schilling, Arndt F; Machens, Hans-Guenther; Gurtner, Geoffrey C; Longaker, Michael T; Wan, Derrick C

    2017-12-01

    Regenerative medicine employs human mesenchymal stromal cells (MSCs) for their multi-lineage plasticity and their pro-regenerative cytokine secretome. Adipose-derived mesenchymal stromal cells (ASCs) are concentrated in fat tissue, and the ease of harvest via liposuction makes them a particularly interesting cell source. However, there are various liposuction methods, and few have been assessed regarding their impact on ASC functionality. Here we study the impact of the two most popular ultrasound-assisted liposuction (UAL) devices currently in clinical use, VASER (Solta Medical) and Lysonix 3000 (Mentor) on ASCs. After lipoaspirate harvest and processing, we sorted for ASCs using fluorescent-assisted cell sorting based on an established surface marker profile (CD34 + CD31 - CD45 - ). ASC yield, viability, osteogenic and adipogenic differentiation capacity and in vivo regenerative performance were assessed. Both UAL samples demonstrated equivalent ASC yield and viability. VASER UAL ASCs showed higher osteogenic and adipogenic marker expression, but a comparable differentiation capacity was observed. Soft tissue healing and neovascularization were significantly enhanced via both UAL-derived ASCs in vivo, and there was no significant difference between the cell therapy groups. Taken together, our data suggest that UAL allows safe and efficient harvesting of the mesenchymal stromal cellular fraction of adipose tissue and that cells harvested via this approach are suitable for cell therapy and tissue engineering applications. Copyright © 2017 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

  8. Mapping of an ultrasonic bath for ultrasound assisted extraction of mangiferin from Mangifera indica leaves.

    Science.gov (United States)

    Kulkarni, Vrushali M; Rathod, Virendra K

    2014-03-01

    The present work deals with the mapping of an ultrasonic bath for the maximum extraction of mangiferin from Mangifera indica leaves. I3(-) liberation experiments (chemical transformations) and extraction (physical transformations) were carried out at different locations in an ultrasonic bath and compared. The experimental findings indicated a similar trend in variation in an ultrasonic bath by both these methods. Various parameters such as position and depth of vessel in an ultrasonic bath, diameter and shape of a vessel, frequency and input power which affect the extraction yield have been studied in detail. Maximum yield of mangiferin obtained was approximately 31 mg/g at optimized parameters: distance of 2.54 cm above the bottom of the bath, 7 cm diameter of vessel, flat bottom vessel, 6.35 cm liquid height, 122 W input power and 25 kHz frequency. The present work indicates that the position and depth of vessel in an ultrasonic bath, diameter and shape of a vessel, frequency and input power have significant effect on the extraction yield. This work can be used as a base for all ultrasonic baths to obtain maximum efficiency for ultrasound assisted extraction. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Ultrasound-Assisted Extraction and Characterization of Pectic Polysaccharide from Oriental Tobacco Leaves

    International Nuclear Information System (INIS)

    Liu, S.; Tian, Z.; Li, X.; He, P.; Xu, C.

    2015-01-01

    Ultrasound-assisted extraction (UAE) of pectic Polysaccharide from oriental tobacco leaves was studied by orthogonal matrix method (L9(3)4). Furthermore, the crude Polysaccharide was purified and two components (Fr-I and Fr-II) were obtained. FT-IR spectral analysis of the purified EPS revealed prominent characteristic groups. The monosaccharide composition analysis indicated the main composition between Fr-I and Fr-II was different. Furthermore, thermo gravimetric analysis (TGA) indicated the degradation temperature (Td) of the Fr-I (215 degree C) was higher than those of Fr-II (162 degree C). Detected by the pyrolysis GC/MS, though the main kinds of pyrolysis products from both Fr-I and Fr-II were similar, the larger amount of heterocycle and aromatic compounds liberated after hydrolysis of Fr-II. Finally, On the basis of the antioxidant activity test in vitro, Fr-II has stronger antioxidant activities than Fr-I. The thermal behavior and antioxidant activity might be attributed to the configuration of the sugar units and chemical compositions. (author)

  10. Ultrasound-Assisted Extraction, Antioxidant and Anticancer Activities of the Polysaccharides from Rhynchosia minima Root

    Directory of Open Access Journals (Sweden)

    Xuejing Jia

    2015-11-01

    Full Text Available Box-Behnken design (BBD, one of the most common response surface methodology (RSM methods, was used to optimize the experimental conditions for ultrasound-assisted extraction of polysaccharides from Rhynchosia minima root (PRM. The antioxidant abilities and anticancer activity of purified polysaccharide fractions were also measured. The results showed that optimal extraction parameters were as follows: ultrasound exposure time, 21 min; ratio of water to material, 46 mL/g; ultrasound extraction temperature, 63 °C. Under these conditions, the maximum yield of PRM was 16.95% ± 0.07%. Furthermore, the main monosaccharides of purified fractions were Ara and Gal. PRM3 and PRM5 exhibited remarkable DPPH radical scavenging activities and reducing power in vitro. PRM3 showed strong inhibitory activities on the growth of MCF-7 cells in vitro. The above results indicate that polysaccharides from R. minima root have the potential to be developed as natural antioxidants and anticancer ingredients for the food and pharmaceutical industries.

  11. Optimization of Ultrasound-Assisted Extraction of Natural Antioxidants from the Osmanthus fragrans Flower.

    Science.gov (United States)

    Li, An-Na; Li, Sha; Li, Ya; Xu, Dong-Ping; Li, Hua-Bin

    2016-02-18

    An ultrasound-assisted extraction (UAE) method was developed to extract natural antioxidants from the Osmanthus fragrans flower. The effect of UAE on antioxidant activity of the extract from the Osmanthus fragrans flower was studied using a Trolox equivalent antioxidant capacity (TEAC) assay. Optimization conditions were firstly determined using a single-factor experiment, and response surface methodology was then used to evaluate interaction of several experimental parameters. Analysis of the coefficient of determination showed that second-order polynomial models produced a highly satisfactory fitting of the experimental data with regard to TEAC values (R² = 0.9829, p extraction for 35.2 min at 59.4 °C. Under these conditions, the maximum TEAC value was 584.9 ± 6.0 μmol Trolox/g DW, which was higher than those obtained by the conventional extracting method (486.4 ± 12.6 μmol Trolox/g DW) and the Soxhlet extraction method (339.1 ± 16.2 μmol Trolox/g DW). The crude extract obtained could be used either as a food additive or in pharmaceuticals for the prevention and treatment of diseases caused by oxidative stress.

  12. Optimization of Ultrasound-Assisted Extraction of Antioxidants from the Mung Bean Coat.

    Science.gov (United States)

    Zhou, Yue; Zheng, Jie; Gan, Ren-You; Zhou, Tong; Xu, Dong-Ping; Li, Hua-Bin

    2017-04-15

    Mung bean ( Vigna radiata ) sprout is commonly consumed as a vegetable, while the coat of the germinated mung bean is a waste. In this paper, an ultrasound-assisted extraction method has been developed to extract natural antioxidants from the seed coat of mung bean. Several experimental parameters-which included ethanol concentration, solvent/material ratio, ultrasound extraction time, temperature, and power-were studied in single-factor experiments. The interaction of three key experimental parameters (ethanol concentration, solvent/material ratio, and ultrasonic extraction time) was further investigated by response surface method. Besides, traditional extracting methods, including maceration and Soxhlet extraction methods, were also carried out for comparison. The results suggested that the best extracting condition was 37.6% ( v / v ) of ethanol concentration, 35.1:1 mL/g of solvent/material ratio and ultrasonic extraction of 46.1 min at 70 °C under 500 W ultrasonic irradiation. The antioxidant capacity (178.28 ± 7.39 µmol Trolox/g DW) was much stronger than those obtained by the maceration extraction process (158.66 ± 4.73 µmol Trolox/g DW) and the Soxhlet extraction process (138.42 ± 3.63 µmol Trolox/g DW). In addition, several antioxidant components in the extract were identified and quantified. This study is helpful for value-added utilization of the waste from germinated mung bean.

  13. Ultrasound-assisted extraction of polyphenols from native plants in the Mexican desert.

    Science.gov (United States)

    Wong Paz, Jorge E; Muñiz Márquez, Diana B; Martínez Ávila, Guillermo C G; Belmares Cerda, Ruth E; Aguilar, Cristóbal N

    2015-01-01

    Several plants that are rich in polyphenolic compounds and exhibit biological properties are grown in the desert region of Mexico under extreme climate conditions. These compounds have been recovered by classic methodologies in these plants using organic solvents. However, little information is available regarding the use of alternative extraction technologies, such as ultrasound. In this paper, ultrasound-assisted extraction (UAE) parameters, such as the liquid:solid ratio, solvent concentration and extraction time, were studied using response surface methodology (RSM) for the extraction of polyphenols from desert plants including Jatrophadioica,Flourensiacernua, Turneradiffusa and Eucalyptuscamaldulensis. Key process variables (i.e., liquid:solid ratio and ethanol concentration) exert the greatest influence on the extraction of all of the phenolic compounds (TPC) in the studied plants. The best conditions for the extraction of TPC involved an extraction time of 40min, an ethanol concentration of 35% and a liquid:solid ratio ranging from 8 to 12mlg(-1) depending on the plant. The highest antioxidant activity was obtained in the E. camaldulensis extracts. The results indicated the ability of UAE to obtain polyphenolic antioxidant preparations from desert plants. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Ultrasound-Assisted Extraction, Antioxidant and Anticancer Activities of the Polysaccharides from Rhynchosia minima Root.

    Science.gov (United States)

    Jia, Xuejing; Zhang, Chao; Hu, Jie; He, Muxue; Bao, Jiaolin; Wang, Kai; Li, Peng; Chen, Meiwan; Wan, Jianbo; Su, Huanxing; Zhang, Qingwen; He, Chengwei

    2015-11-23

    Box-Behnken design (BBD), one of the most common response surface methodology (RSM) methods, was used to optimize the experimental conditions for ultrasound-assisted extraction of polysaccharides from Rhynchosia minima root (PRM). The antioxidant abilities and anticancer activity of purified polysaccharide fractions were also measured. The results showed that optimal extraction parameters were as follows: ultrasound exposure time, 21 min; ratio of water to material, 46 mL/g; ultrasound extraction temperature, 63 °C. Under these conditions, the maximum yield of PRM was 16.95%±0.07%. Furthermore, the main monosaccharides of purified fractions were Ara and Gal. PRM3 and PRM5 exhibited remarkable DPPH radical scavenging activities and reducing power in vitro. PRM3 showed strong inhibitory activities on the growth of MCF-7 cells in vitro. The above results indicate that polysaccharides from R. minima root have the potential to be developed as natural antioxidants and anticancer ingredients for the food and pharmaceutical industries.

  15. Optimization of ultrasound-assisted extraction (UAE) of phenolic compounds from olive cake.

    Science.gov (United States)

    Mojerlou, Zohreh; Elhamirad, Amirhhossein

    2018-03-01

    The use of ultrasound in ultrasound-assisted extraction (UAE) is one of the main applications of this technology in food industry. This study aimed to optimize UAE conditions for olive cake extract (OCE) through response surface methodology (RSM). The optimal UAE conditions were obtained with extraction temperature of 56 °C, extraction time of 3 min, duty cycle of 0.6 s, and solid to solvent ratio of 3.6%. At the optimum conditions, the total phenolic compounds (TPC) content and antioxidant activity (AA) were measured 4.04 mg/g and 68.9%, respectively. The linear term of temperature had the most effect on TPC content and AA of OCE prepared by UAE. Protocatechuic acid and cinnamic acid were characterized as the highest (19.5%) and lowest (1.6%) phenolic compound measured in OCE extracted by UAE. This research revealed that UAE is an effective method to extract phenolic compounds from olive cake. RSM successfully optimized UAE conditions for OCE.

  16. Ultrasound-assisted oxidative desulfurization of liquid fuels and its industrial application.

    Science.gov (United States)

    Wu, Zhilin; Ondruschka, Bernd

    2010-08-01

    Latest environmental regulations require a very deep desulfurization to meet the ultra-low sulfur diesel (ULSD, 15 ppm sulfur) specifications. Due to the disadvantages of hydrotreating technology on the slashing production conditions, costs and safety as well as environmental protection, the ultrasound-assisted oxidative desulfurization (UAOD) as an alternative technology has been developed. UAOD process selectively oxidizes sulfur in common thiophenes in diesel to sulfoxides and sulfones which can be removed via selective adsorption or extractant. SulphCo has successfully used a 5000 barrel/day mobile "Sonocracking" unit to duplicate on a commercial scale its proprietary process that applies ultrasonics at relatively low temperatures and pressures. The UAOD technology estimate capital costs less than half the cost of a new high-pressure hydrotreater. The physical and chemical mechanisms of UAOD process are illustrated, and the effective factors, such as ultrasonic frequency and power, oxidants, catalysts, phase-transfer agent, extractant and adsorbent, on reaction kinetics and product recovery are discussed in this review. Copyright 2009 Elsevier B.V. All rights reserved.

  17. Ultrasound-assisted extraction of three bufadienolides from Chinese medicine ChanSu.

    Science.gov (United States)

    Sun, Yinshi; Bi, Jianjie; Zhang, Li; Ye, Baoxing

    2012-11-01

    In this study, the application of ultrasound-assisted extraction (UAE) method was shown to be more efficient in extracting anti-tumor bufadienolides (bufalin, cinobufagin and resibufogenin) from important animal medicine of ChanSu than the maceration extraction (ME) and soxhlet extraction (SE) method. The effects of ultrasonic variables including extraction solvent, solvent concentration, solvent to solid ratio, ultrasound power, temperature, extraction time and particle size on the yields of three bufadienolides were investigated. The optimum extraction conditions found were: 70% (v/v) methanol solution, solvent to solid ratio of 10ml/g, ultrasound power of 125W, temperature of 20°C, extraction time of 20min and particle size of 60-80 mesh. The extraction yields of bufalin, cinobufagin and resibufogenin were 43.17±0.85, 52.58±1.12, 137.70±2.65mg/g, respectively. In order to achieve a similar yield as UAE, soxhlet extraction required 6h and maceration extraction required much longer time of 18h. The results indicated that UAE is an alternative method for extracting bufadienolides from ChanSu. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. Optimization of ultrasound-assisted extraction of charantin from Momordica charantia fruits using response surface methodology

    Directory of Open Access Journals (Sweden)

    Javed Ahamad

    2015-01-01

    Full Text Available Background: Momordica charantia Linn. (Cucurbitaceae fruits are well known for their beneficial effects in diabetes that are often attributed to its bioactive component charantin. Objective: The aim of the present study is to develop and optimize an efficient protocol for the extraction of charantin from M. charantia fruits. Materials and Methods: Response surface methodology (RSM was used for the optimization of ultrasound-assisted extraction (UAE conditions. RSM was based on a three-level, three-variable Box-Behnken design (BBD, and the studied variables included solid to solvent ratio, extraction temperature, and extraction time. Results: The optimal conditions predicted by the BBD were: UAE with methanol: Water (80:20, v/v at 46°C for 120 min with solid to solvent ratio of 1:26 w/v, under which the yield of charantin was 3.18 mg/g. Confirmation trials under slightly adjusted conditions yielded 3.12 ± 0.14 mg/g of charantin on dry weight basis of fruits. The result of UAE was also compared with Soxhlet extraction method and UAE was found 2.74-fold more efficient than the Soxhlet extraction for extracting charantin. Conclusions:A facile UAE protocol for a high extraction yield of charantin was developed and validated.

  19. Optimization of ultrasound-assisted extraction of charantin from Momordica charantia fruits using response surface methodology.

    Science.gov (United States)

    Ahamad, Javed; Amin, Saima; Mir, Showkat R

    2015-01-01

    Momordica charantia Linn. (Cucurbitaceae) fruits are well known for their beneficial effects in diabetes that are often attributed to its bioactive component charantin. The aim of the present study is to develop and optimize an efficient protocol for the extraction of charantin from M. charantia fruits. Response surface methodology (RSM) was used for the optimization of ultrasound-assisted extraction (UAE) conditions. RSM was based on a three-level, three-variable Box-Behnken design (BBD), and the studied variables included solid to solvent ratio, extraction temperature, and extraction time. The optimal conditions predicted by the BBD were: UAE with methanol: Water (80:20, v/v) at 46°C for 120 min with solid to solvent ratio of 1:26 w/v, under which the yield of charantin was 3.18 mg/g. Confirmation trials under slightly adjusted conditions yielded 3.12 ± 0.14 mg/g of charantin on dry weight basis of fruits. The result of UAE was also compared with Soxhlet extraction method and UAE was found 2.74-fold more efficient than the Soxhlet extraction for extracting charantin. A facile UAE protocol for a high extraction yield of charantin was developed and validated.

  20. Ultrasound assisted combustion synthesis of TiC in Al-Ti-C system.

    Science.gov (United States)

    Liu, Zhiwei; Rakita, Milan; Xu, Wilson; Wang, Xiaoming; Han, Qingyou

    2015-11-01

    This research investigated the effects of high-intensity ultrasound on the combustion synthesis of TiC particles in Al-Ti-C system. The process involved that high-intensity ultrasound was applied on the surface of a compacted Al-Ti-C pellet directly through a Nb probe during the thermal explosion reaction. By comparing with the sample without ultrasonic treatment, it was found that the thermal explosion reaction for synthesizing TiC phase could take place thoroughly in the ultrasonically treated sample. During the process of synthesizing TiC phase, the dissolution of solid graphite particles into the Al-Ti melt, as well as the nucleation and growth of TiC particles could be promoted effectively due to the effects of ultrasound, leading to an enhancement of the formation of TiC particles. Ultrasound assisted combustion synthesis as a simple and effective approach was proposed for synthesizing materials in this research. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Ultrasound-Assisted Transient Liquid Phase Bonding of Magnesium Alloy Using Brass Interlayer in Air

    Institute of Scientific and Technical Information of China (English)

    Zhiwei Lai; Ruishan Xie; Chuan Pan; Xiaoguang Chen; Lei Liu; Wenxian Wang; Guisheng Zou

    2017-01-01

    The microstructure evolution and oxide film behavior in ultrasound-assisted transient liquid phase (U-TLP) bonding of Mg alloy were investigated by applying different ultrasonic time at 460℃ withbrass interlayer in air.The results indicated that with increasing ultrasonic time,brass interlayer disappeared gradually and the Mg-Cu-Zn eutectic compounds were formed.The eutectic compounds in the joint decreased as the ultrasonic time increased further.The oxide removal process was divided into four steps.Continuous oxide film at the interface was partially fractured by ultrasonic vibration,and then suspended into liquid by undermining eutectic reaction.After that,the suspended oxide film was broken into small oxide fragments by ultrasonic cavitation effect,which was finally squeezed out of the joint by ultrasonic squeeze action.In addition,the mechanical properties of the joints were investigated.The maximum shear strength of the joint reached 105 MPa,which was 100% of base metal.

  2. Process optimization of ultrasound-assisted alcoholic-alkaline treatment for granular cold water swelling starches.

    Science.gov (United States)

    Zhu, Bo; Liu, Jianli; Gao, Weidong

    2017-09-01

    This paper reports on the process optimization of ultrasonic assisted alcoholic-alkaline treatment to prepare granular cold water swelling (GCWS) starches. In this work, three statistical approaches such as Plackett-Burman, steepest ascent path analysis and Box-Behnken design were successfully combined to investigate the effects of major treatment process variables including starch concentration, ethanol volume fraction, sodium hydroxide dosage, ultrasonic power and treatment time, and drying operation, that is, vacuum degree and drying time on cold-water solubility. Results revealed that ethanol volume fraction, sodium hydroxide dosage, applied power and ultrasonic treatment time were significant factors that affected the cold-water solubility of GCWS starches. The maximum cold-water solubility was obtained when treated at 400W of applied power for 27.38min. Optimum volume fraction of ethanol and sodium hydroxide dosage were 66.85% and 53.76mL, respectively. The theoretical values (93.87%) and the observed values (93.87%) were in reasonably good agreement and the deviation was less than 1%. Verification and repeated trial results indicated that the ultrasound-assisted alcoholic-alkaline treatment could be successfully used for the preparation of granular cold water swelling starches at room temperatures and had excellent improvement on the cold-water solubility of GCWS starches. Copyright © 2016. Published by Elsevier B.V.

  3. Optimisation of ultrasound-assisted osmotic dehydration of sweet potato (Ipomea batatas) using response surface methodology.

    Science.gov (United States)

    Oladejo, Ayobami Olayemi; Ma, Haile

    2016-08-01

    Sweet potato is a highly nutritious tuber crop that is rich in β-carotene. Osmotic dehydration is a pretreatment method for drying of fruit and vegetables. Recently, ultrasound technology has been applied in food processing because of its numerous advantages which include time saving, little damage to the quality of the food. Thus, there is need to investigate and optimise the process parameters [frequency (20-50 kHz), time (10-30 min) and sucrose concentration (20-60% w/v)] for ultrasound-assisted osmotic dehydration of sweet potato using response surface methodology. The optimised values obtained were frequency of 33.93 kHz, time of 30 min and sucrose concentration of 35.69% (w/v) to give predicted values of 21.62, 4.40 and 17.23% for water loss, solid gain and weight reduction, respectively. The water loss and weight reduction increased when the ultrasound frequency increased from 20 to 35 kHz and then decreased as the frequency increased from 35 to 50 kHz. The results from this work show that low ultrasound frequency favours the osmotic dehydration of sweet potato and also reduces the use of raw material (sucrose) needed for the osmotic dehydration of sweet potato. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  4. Ultrasound-assisted extraction of polyphenols from Thymus serpyllum and its antioxidant activity

    Directory of Open Access Journals (Sweden)

    Jovanović Aleksandra A.

    2016-01-01

    Full Text Available The present study was designed to establish and optimize a method for extracting natural bioactive compounds from Thymus serpyllum which possess antioxidant, antimicrobial, antispasmotic and stimulant properties. Ultrasound-assisted extraction (UAE is a well-established method in the processing of plant material, particularly for extraction of bioactive substances such as polyphenols. The influential factors including extraction time (3, 7 and 10 minutes, solid:solvent ratio (1:10, 1:20 and 1:30 and particle size (0.3, 0.7 and 1.5 mm, have been studied to optimize the extraction process, while using 30% ethanol as an extraction medium and amplitude set to 65%. The yield of UAE was expressed via total phenol content and antioxidant activity of the obtained extracts. The optimum process paremeters were found to be: extraction time, 3 min; solid:solvent ratio, 1:30; particle size, 0.3 mm. Under these conditions, the yield of total polyphenols was raised up to 23.03 mg/L GA and the highest antioxidant activity was recorded (10.32 mmol/mg Trolox and IC50 3.00 mg/ml. [Projekat Ministarstva nauke Republike Srbije, br. 46010 i br. 46013

  5. Ultrasound Assisted Extraction for the Recovery of Phenolic Compounds from Vegetable Sources

    Directory of Open Access Journals (Sweden)

    Nelly Medina-Torres

    2017-07-01

    Full Text Available Vegetable sources and agro-industrial residues represent an important source of phenolic compounds that are useful in a wide range of applications, especially those with biological activities. Conventional techniques of phytochemical extraction have been associated with a high consumption of organic solvents that limits the application of bioactive extracts, leading to the implementation of novel extraction technologies using mechanisms such as Ultrasound Assisted Extraction (UAE. In the present review, an analysis of the involved variables in the extraction yield of phenolic compounds through UAE is presented, highlighting the advantages of this technology based on the results obtained in various optimized studies. A comparison with other technologies and a proposal of its possible application for agro industrial residues as raw material of phenolic compounds is also indicated. Finally, it is concluded that UAE is a technology that is placed within the area of Sustainable Chemistry since it promotes the use of renewable raw materials through the extraction of phenolic compounds, implementing the substitution of organic solvents with solvents that do not present toxic effects, lowering the energy consumption when compared to conventional methods and minimizing process times and temperatures, which is useful for the extraction of thermo-labile compounds.

  6. Batch and Continuous Ultrasound Assisted Extraction of Boldo Leaves (Peumus boldus Mol.

    Directory of Open Access Journals (Sweden)

    Joël Wajsman

    2013-03-01

    Full Text Available Vegetal extracts are widely used as primary ingredients for various products from creams to perfumes in the pharmaceutical, nutraceutic and cosmetic industries. Having concentrated and active extract is essential, as the process must extract as much soluble material as possible in a minimum time, using the least possible volume of solvent. The boldo leaves extract is of great interest for the industry as it holds a great anti-oxidant activity due to high levels of flavonoids and alkaloids such as boldine. Ultrasound Assisted Extraction (UAE has been used to improve the efficiency of the plant extraction, reducing extraction time, increasing the concentration of the extract with the same amount of solvent and plant material. After a preliminary study, a response surface method has been used to optimize the extraction of soluble material from the plant. The results provided by the statistical analysis revealed that the optimized conditions were: sonication power 23 W/cm2 for 40 min and a temperature of 36 °C. The optimized parameters of the UAE provide a better extraction compared to a conventional maceration in terms of process time (30 min instead of 120 min, higher yield, more energy saving, cleanliness, safety and product quality.

  7. Batch and Continuous Ultrasound Assisted Extraction of Boldo Leaves (Peumus boldus Mol.).

    Science.gov (United States)

    Petigny, Loïc; Périno-Issartier, Sandrine; Wajsman, Joël; Chemat, Farid

    2013-03-12

    Vegetal extracts are widely used as primary ingredients for various products from creams to perfumes in the pharmaceutical, nutraceutic and cosmetic industries. Having concentrated and active extract is essential, as the process must extract as much soluble material as possible in a minimum time, using the least possible volume of solvent. The boldo leaves extract is of great interest for the industry as it holds a great anti-oxidant activity due to high levels of flavonoids and alkaloids such as boldine. Ultrasound Assisted Extraction (UAE) has been used to improve the efficiency of the plant extraction, reducing extraction time, increasing the concentration of the extract with the same amount of solvent and plant material. After a preliminary study, a response surface method has been used to optimize the extraction of soluble material from the plant. The results provided by the statistical analysis revealed that the optimized conditions were: sonication power 23 W/cm2 for 40 min and a temperature of 36 °C. The optimized parameters of the UAE provide a better extraction compared to a conventional maceration in terms of process time (30 min instead of 120 min), higher yield, more energy saving, cleanliness, safety and product quality.

  8. Optimization of Ficus deltoidea Using Ultrasound-Assisted Extraction by Box-Behnken Statistical Design

    Directory of Open Access Journals (Sweden)

    L. J. Ong

    2016-09-01

    Full Text Available In this study, the effect of extraction parameters (ethanol concentration, sonication time, and solvent-to-sample ratio on Ficus deltoidea leaves was investigated using ultrasound-assisted extraction by response surface methodology (RSM. Total phenolic content (TPC of F. deltoidea extracts was identified using Folin-Ciocalteu method and expressed in gallic acid equivalent (GAE per g. Box-Behnken statistical design (BBD was the tool used to find the optimal conditions for maximum TPC. Besides, the extraction yield was measured and stated in percentage. The optimized TPC attained was 455.78 mg GAE/g at 64% ethanol concentration, 10 minutes sonication time, and 20 mL/g solvent-to-sample ratio whereas the greatest extraction yield was 33% with ethanol concentration of 70%, sonication time of 40 minutes, and solvent-to-material ratio at 40 mL/g. The determination coefficient, R2, for TPC indicates that 99.5% capriciousness in the response could be clarified by the ANOVA model and the value of 0.9681 of predicted R2 is in equitable agreement with the 0.9890 of adjusted R2. The present study shows that ethanol water as solvent, a short time of 10 minutes, and adequate solvent-to-sample ratio (20 mL/g are the best conditions for extraction.

  9. Ultrasound-assisted extraction for total sulphur measurement in mine tailings

    International Nuclear Information System (INIS)

    Khan, Adnan Hossain; Shang, Julie Q.; Alam, Raquibul

    2012-01-01

    Highlights: ► We develop a total sulphur measuring procedure of mine tailings. ► Ultrasound is used in the sample pre-treatment process. ► Full factorial design is applied to identify the best level of effecting factors. - Abstract: A sample preparation method for percentage recovery of total sulphur (%S) in reactive mine tailings based on ultrasound-assisted digestion (USAD) and inductively coupled plasma-optical emission spectroscopy (ICP-OES) was developed. The influence of various methodological factors was screened by employing a two-level and three-factor (2 3 ) full factorial design and using KZK-1, a sericite schist certified reference material (CRM), to find the optimal combination of studied factors and %S. Factors such as the sonication time, temperature and acid combination were studied, with the best result identified as 20 min of sonication, 80 °C temperature and 1 ml of HNO 3 :1 ml of HCl, which can achieve 100% recovery for the selected CRM. Subsequently a fraction of the 2 3 full factorial design was applied to mine tailings. The percentage relative standard deviation (%RSD) for the ultrasound method is less than 3.0% for CRM and less than 6% for the mine tailings. The investigated method was verified by X-ray diffraction analysis. The USAD method compared favorably with existing methods such as hot plate assisted digestion method, X-ray fluorescence and LECO™-CNS method.

  10. Ultrasound-assisted extraction for total sulphur measurement in mine tailings.

    Science.gov (United States)

    Khan, Adnan Hossain; Shang, Julie Q; Alam, Raquibul

    2012-10-15

    A sample preparation method for percentage recovery of total sulphur (%S) in reactive mine tailings based on ultrasound-assisted digestion (USAD) and inductively coupled plasma-optical emission spectroscopy (ICP-OES) was developed. The influence of various methodological factors was screened by employing a two-level and three-factor (2(3)) full factorial design and using KZK-1, a sericite schist certified reference material (CRM), to find the optimal combination of studied factors and %S. Factors such as the sonication time, temperature and acid combination were studied, with the best result identified as 20 min of sonication, 80°C temperature and 1 ml of HNO(3):1 ml of HCl, which can achieve 100% recovery for the selected CRM. Subsequently a fraction of the 2(3) full factorial design was applied to mine tailings. The percentage relative standard deviation (%RSD) for the ultrasound method is less than 3.0% for CRM and less than 6% for the mine tailings. The investigated method was verified by X-ray diffraction analysis. The USAD method compared favorably with existing methods such as hot plate assisted digestion method, X-ray fluorescence and LECO™-CNS method. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. Ultrasound-Assist Extrusion Methods for the Fabrication of Polymer Nanocomposites Based on Polypropylene/Multi-Wall Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Carlos A. Ávila-Orta

    2015-11-01

    Full Text Available Isotactic polypropylenes (iPP with different melt flow indexes (MFI were used to fabricate nanocomposites (NCs with 10 wt % loadings of multi-wall carbon nanotubes (MWCNTs using ultrasound-assisted extrusion methods to determine their effect on the morphology, melt flow, and electrical properties of the NCs. Three different types of iPPs were used with MFIs of 2.5, 34 and 1200 g/10 min. Four different NC fabrication methods based on melt extrusion were used. In the first method melt extrusion fabrication without ultrasound assistance was used. In the second and third methods, an ultrasound probe attached to a hot chamber located at the exit of the die was used to subject the sample to fixed frequency and variable frequency, respectively. The fourth method is similar to the first method, with the difference being that the carbon nanotubes were treated in a fluidized air-bed with an ultrasound probe before being used in the fabrication of the NCs with no ultrasound assistance during extrusion. The samples were characterized by MFI, Optical microscopy (OM, Scanning electron microscopy (SEM, Transmission electron microscopy (TEM, electrical surface resistivity, and electric charge. MFI decreases in all cases with addition of MWCNTs with the largest decrease observed for samples with the highest MFI. The surface resistivity, which ranged from 1013 to 105 Ω/sq, and electric charge, were observed to depend on the ultrasound-assisted fabrication method as well as on the melt flow index of the iPP. A relationship between agglomerate size and area ratio with electric charge was found. Several trends in the overall data were identified and are discussed in terms of MFI and the different fabrication methods.

  12. Ultrasound-Assist Extrusion Methods for the Fabrication of Polymer Nanocomposites Based on Polypropylene/Multi-Wall Carbon Nanotubes

    Science.gov (United States)

    Ávila-Orta, Carlos A.; Quiñones-Jurado, Zoe V.; Waldo-Mendoza, Miguel A.; Rivera-Paz, Erika A.; Cruz-Delgado, Víctor J.; Mata-Padilla, José M.; González-Morones, Pablo; Ziolo, Ronald F.

    2015-01-01

    Isotactic polypropylenes (iPP) with different melt flow indexes (MFI) were used to fabricate nanocomposites (NCs) with 10 wt % loadings of multi-wall carbon nanotubes (MWCNTs) using ultrasound-assisted extrusion methods to determine their effect on the morphology, melt flow, and electrical properties of the NCs. Three different types of iPPs were used with MFIs of 2.5, 34 and 1200 g/10 min. Four different NC fabrication methods based on melt extrusion were used. In the first method melt extrusion fabrication without ultrasound assistance was used. In the second and third methods, an ultrasound probe attached to a hot chamber located at the exit of the die was used to subject the sample to fixed frequency and variable frequency, respectively. The fourth method is similar to the first method, with the difference being that the carbon nanotubes were treated in a fluidized air-bed with an ultrasound probe before being used in the fabrication of the NCs with no ultrasound assistance during extrusion. The samples were characterized by MFI, Optical microscopy (OM), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), electrical surface resistivity, and electric charge. MFI decreases in all cases with addition of MWCNTs with the largest decrease observed for samples with the highest MFI. The surface resistivity, which ranged from 1013 to 105 Ω/sq, and electric charge, were observed to depend on the ultrasound-assisted fabrication method as well as on the melt flow index of the iPP. A relationship between agglomerate size and area ratio with electric charge was found. Several trends in the overall data were identified and are discussed in terms of MFI and the different fabrication methods. PMID:28793686

  13. Comparison of ultrasound-assisted and traditional caustic leaching of spent cathode carbon (SCC) from aluminum electrolysis.

    Science.gov (United States)

    Xiao, Jin; Yuan, Jie; Tian, Zhongliang; Yang, Kai; Yao, Zhen; Yu, Bailie; Zhang, Liuyun

    2018-01-01

    The spent cathode carbon (SCC) from aluminum electrolysis was subjected to caustic leaching to investigate the different effects of ultrasound-assisted and traditional methods on element fluorine (F) leaching rate and leaching residue carbon content. Sodium hydroxide (NaOH) dissolved in deionized water was used as the reaction system. Through single-factor experiments and a comparison of two leaching techniques, the optimum F leaching rate and residue carbon content for ultrasound-assisted leaching process were obtained at a temperature of 70°C, residue time of 40min, initial mass ratio of alkali to SCC (initial alkali-to-material ratio) of 0.6, liquid-to-solid ratio of 10mL/g, and ultrasonic power of 400W, respectively. Under the optimal conditions, the leaching residue carbon content was 94.72%, 2.19% larger than the carbon content of traditional leaching residue. Leaching wastewater was treated with calcium chloride (CaCl 2 ) and bleaching powder and the treated wastewater was recycled caustic solution. All in all, benefiting from advantage of the ultrasonication effects, ultrasound-assisted caustic leaching on spent cathode carbon had 55.6% shorter residue time than the traditional process with a higher impurity removal rate. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Ultrasound-assisted extraction (UAE) and solvent extraction of papaya seed oil: yield, fatty acid composition and triacylglycerol profile.

    Science.gov (United States)

    Samaram, Shadi; Mirhosseini, Hamed; Tan, Chin Ping; Ghazali, Hasanah Mohd

    2013-10-10

    The main objective of the current work was to evaluate the suitability of ultrasound-assisted extraction (UAE) for the recovery of oil from papaya seed as compared to conventional extraction techniques (i.e., Soxhlet extraction (SXE) and solvent extraction (SE)). In the present study, the recovery yield, fatty acid composition and triacylglycerol profile of papaya seed oil obtained from different extraction methods and conditions were compared. Results indicated that both solvent extraction (SE, 12 h/25 °C) and ultrasound-assisted extraction (UAE) methods recovered relatively high yields (79.1% and 76.1% of total oil content, respectively). Analysis of fatty acid composition revealed that the predominant fatty acids in papaya seed oil were oleic (18:1, 70.5%-74.7%), palmitic (16:0, 14.9%-17.9%), stearic (18:0, 4.50%-5.25%), and linoleic acid (18:2, 3.63%-4.6%). Moreover, the most abundant triacylglycerols of papaya seed oil were triolein (OOO), palmitoyl diolein (POO) and stearoyl oleoyl linolein (SOL). In this study, ultrasound-assisted extraction (UAE) significantly (p < 0.05) influenced the triacylglycerol profile of papaya seed oil, but no significant differences were observed in the fatty acid composition of papaya seed oil extracted by different extraction methods (SXE, SE and UAE) and conditions.

  15. Ultrasound-Assisted Extraction (UAE and Solvent Extraction of Papaya Seed Oil: Yield, Fatty Acid Composition and Triacylglycerol Profile

    Directory of Open Access Journals (Sweden)

    Hasanah Mohd Ghazali

    2013-10-01

    Full Text Available The main objective of the current work was to evaluate the suitability of ultrasound-assisted extraction (UAE for the recovery of oil from papaya seed as compared to conventional extraction techniques (i.e., Soxhlet extraction (SXE and solvent extraction (SE. In the present study, the recovery yield, fatty acid composition and triacylglycerol profile of papaya seed oil obtained from different extraction methods and conditions were compared. Results indicated that both solvent extraction (SE, 12 h/25 °C and ultrasound-assisted extraction (UAE methods recovered relatively high yields (79.1% and 76.1% of total oil content, respectively. Analysis of fatty acid composition revealed that the predominant fatty acids in papaya seed oil were oleic (18:1, 70.5%–74.7%, palmitic (16:0, 14.9%–17.9%, stearic (18:0, 4.50%–5.25%, and linoleic acid (18:2, 3.63%–4.6%. Moreover, the most abundant triacylglycerols of papaya seed oil were triolein (OOO, palmitoyl diolein (POO and stearoyl oleoyl linolein (SOL. In this study, ultrasound-assisted extraction (UAE significantly (p < 0.05 influenced the triacylglycerol profile of papaya seed oil, but no significant differences were observed in the fatty acid composition of papaya seed oil extracted by different extraction methods (SXE, SE and UAE and conditions.

  16. Superoxide radical and UV irradiation in ultrasound assisted oxidative desulfurization (UAOD): A potential alternative for greener fuels

    Science.gov (United States)

    Chan, Ngo Yeung

    This study is aimed at improving the current ultrasound assisted oxidative desulfurization (UAOD) process by utilizing superoxide radical as oxidant. Research was also conducted to investigate the feasibility of ultraviolet (UV) irradiation-assisted desulfurization. These modifications can enhance the process with the following achievements: (1) Meet the upcoming sulfur standards on various fuels including diesel fuel oils and residual oils; (2) More efficient oxidant with significantly lower consumption in accordance with stoichiometry; (3) Energy saving by 90%; (4) Greater selectivity in petroleum composition. Currently, the UAOD process and subsequent modifications developed in University of Southern California by Professor Yen's research group have demonstrated high desulfurization efficiencies towards various fuels with the application of 30% wt. hydrogen peroxide as oxidant. The UAOD process has demonstrated more than 50% desulfurization of refractory organic sulfur compounds with the use of Venturella type catalysts. Application of quaternary ammonium fluoride as phase transfer catalyst has significantly improved the desulfurization efficiency to 95%. Recent modifications incorporating ionic liquids have shown that the modified UAOD process can produce ultra-low sulfur, or near-zero sulfur diesels under mild conditions with 70°C and atmospheric pressure. Nevertheless, the UAOD process is considered not to be particularly efficient with respect to oxidant and energy consumption. Batch studies have demonstrated that the UAOD process requires 100 fold more oxidant than the stoichiometic requirement to achieve high desulfurization yield. The expected high costs of purchasing, shipping and storage of the oxidant would reduce the practicability of the process. The excess use of oxidant is not economically desirable, and it also causes environmental and safety issues. Post treatments would be necessary to stabilize the unspent oxidant residual to prevent the waste

  17. Ionic-Liquid-Based Polymer Electrolytes for Battery Applications.

    Science.gov (United States)

    Osada, Irene; de Vries, Henrik; Scrosati, Bruno; Passerini, Stefano

    2016-01-11

    The advent of solid-state polymer electrolytes for application in lithium batteries took place more than four decades ago when the ability of polyethylene oxide (PEO) to dissolve suitable lithium salts was demonstrated. Since then, many modifications of this basic system have been proposed and tested, involving the addition of conventional, carbonate-based electrolytes, low molecular weight polymers, ceramic fillers, and others. This Review focuses on ternary polymer electrolytes, that is, ion-conducting systems consisting of a polymer incorporating two salts, one bearing the lithium cation and the other introducing additional anions capable of plasticizing the polymer chains. Assessing the state of the research field of solid-state, ternary polymer electrolytes, while giving background on the whole field of polymer electrolytes, this Review is expected to stimulate new thoughts and ideas on the challenges and opportunities of lithium-metal batteries. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Stable Cycling Of Graphite In An Ionic Liquid Based Electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Holzapfel, M.; Jost, C. [Degussa(Georgia); Novak, P.

    2005-03-01

    1-Ethyl-3-methylimidazolium-bis(trifluor methylsulfonyl)-imide (EMI-TFSI) has been shown to reversibly permit lithium intercalation into standard graphite when vinylene carbonate is used in small amounts as additive. (author)

  19. Ultrasound-assisted extraction for total sulphur measurement in mine tailings

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Adnan Hossain, E-mail: ad_li2@yahoo.com [Department of Civil and Environmental Engineering, University of Western Ontario (Canada); Shang, Julie Q.; Alam, Raquibul [Department of Civil and Environmental Engineering, University of Western Ontario (Canada)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer We develop a total sulphur measuring procedure of mine tailings. Black-Right-Pointing-Pointer Ultrasound is used in the sample pre-treatment process. Black-Right-Pointing-Pointer Full factorial design is applied to identify the best level of effecting factors. - Abstract: A sample preparation method for percentage recovery of total sulphur (%S) in reactive mine tailings based on ultrasound-assisted digestion (USAD) and inductively coupled plasma-optical emission spectroscopy (ICP-OES) was developed. The influence of various methodological factors was screened by employing a two-level and three-factor (2{sup 3}) full factorial design and using KZK-1, a sericite schist certified reference material (CRM), to find the optimal combination of studied factors and %S. Factors such as the sonication time, temperature and acid combination were studied, with the best result identified as 20 min of sonication, 80 Degree-Sign C temperature and 1 ml of HNO{sub 3}:1 ml of HCl, which can achieve 100% recovery for the selected CRM. Subsequently a fraction of the 2{sup 3} full factorial design was applied to mine tailings. The percentage relative standard deviation (%RSD) for the ultrasound method is less than 3.0% for CRM and less than 6% for the mine tailings. The investigated method was verified by X-ray diffraction analysis. The USAD method compared favorably with existing methods such as hot plate assisted digestion method, X-ray fluorescence and LECO Trade-Mark-Sign -CNS method.

  20. Reduction of the Areolar Diameter After Ultrasound-Assisted Liposuction for Gynecomastia.

    Science.gov (United States)

    Keskin, Mustafa; Sutcu, Mustafa; Hanci, Mustafa; Cigsar, Bulent

    2017-08-01

    One of the clinical aspects characterizing gynecomastia is the enlargement of the nipple-areolar complex (NAC) due to hypertrophic breast glands, and the excessive fatty tissue underneath. The purpose of this study was to quantify the reduction of the areolar diameter after ultrasound-assisted liposuction (UAL) of the male breast. The horizontal diameters of the NACs of 30 men who underwent UAL were measured before surgery, 1 month after surgery and 6 months after surgery in a standard fashion. Those patients with surgical gland removals of any kind were not included in this study. The mean age of the patients was 27.9 years, and all of the patients had bilateral grade I, II, or III gynecomastia. The mean diameter of the NACs before surgery was 35.36 mm (range, 26-55 mm), and after surgery, the mean diameter of the NACs was initially reduced to 28.8 mm (range, 23-44 mm) and later to 28.57 mm (range, 23-42 mm). The mean volume of breast tissue aspirated was 382 mL per breast, and the percentage of reduction was 17.3%. The reduction of areola diameter was statistically significant after first month. A significant positive correlation was identified between the liposuction volume and areolar diameter reduction. In cases of gynecomastia, the removal of the glandular and fatty tissue underneath the areola releases the expanding forces and pressure that enlarge it. In many cases of gynecomastia, UAL alone is effective in reducing the size of the NAC and allows the surgeon to avoid placing scars on the breast.

  1. Ultrasound-Assisted Extraction and Identification of Natural Antioxidants from the Fruit of Melastoma sanguineum Sims.

    Science.gov (United States)

    Zhou, Tong; Xu, Dong-Ping; Lin, Sheng-Jun; Li, Ya; Zheng, Jie; Zhou, Yue; Zhang, Jiao-Jiao; Li, Hua-Bin

    2017-02-18

    The fruit of Melastoma sanguineum Sims is an edible and sweet wild fruit. In our previous study, the fruit was found to have a strong antioxidant property. In this study, an ultrasound-assisted extraction (UAE) method was developed to extract natural antioxidants from the fruit of Melastoma sanguineum Sims, and a response surface methodology was used to optimize the conditions of UAE to maximize the extraction efficiency. The influence of five independent extraction parameters (ethanol concentration, solvent/material ratio, extracting time, temperature, and ultrasound power) on the extraction efficiency were investigated using a single factor experiment, and then a central composite rotatable design was used to investigate the interaction of three key parameters. The results showed that the optimal extraction conditions were 42.98% ethanol, 28.29 mL/g solvent/material ratio, 34.29 min extracting time, 60 °C temperature, and 600 W ultrasound power. Under these conditions, the Trolox equivalent antioxidant capacity (TEAC) value of the extracts was 1074.61 ± 32.56 μmol Trolox/g dry weight (DW). Compared with conventional maceration (723.27 ± 11.61 μmol Trolox/g DW) and Soxhlet extraction methods (518.37 ± 23.23 μmol Trolox/g DW), the UAE method improved the extraction efficiency, in a shorter period of time. In addition, epicatechin gallate, epicatechin, rutin, epigallocatechin, protocatechuic acid, chlorogenic acid, and quercetin, were identified and quantified in the fruit extracts of Melastoma sanguineum Sims by UPLC-MS/MS.

  2. Ultrasound-assisted acid hydrolysis of cellulose to chemical building blocks: Application to furfural synthesis.

    Science.gov (United States)

    Santos, Daniel; Silva, Ubiratan F; Duarte, Fabio A; Bizzi, Cezar A; Flores, Erico M M; Mello, Paola A

    2018-01-01

    In this work, the use of ultrasound energy for the production of furanic platforms from cellulose was investigated and the synthesis of furfural was demonstrated. Several systems were evaluated, as ultrasound bath, cup horn and probe, in order to investigate microcrystalline cellulose conversion using simply a diluted acid solution and ultrasound. Several acid mixtures were evaluated for hydrolysis, as diluted solutions of HNO 3 , H 2 SO 4 , HCl and H 2 C 2 O 4 . The influence of the following parameters in the ultrasound-assisted acid hydrolysis (UAAH) were studied: sonication temperature (30 to 70°C) and ultrasound amplitude (30 to 70% for a cup horn system) for 4 to 8molL -1 HNO 3 solutions. For each evaluated condition, the products were identified by ultra-performance liquid chromatography with high-resolution time-of-flight mass spectrometry (UPLC-ToF-MS), which provide accurate information regarding the products obtained from biomass conversion. The furfural structure was confirmed by nuclear magnetic resonance ( 1 H and 13 C NMR) spectroscopy. In addition, cellulosic residues from hydrolysis reaction were characterized using scanning electron microscopy (SEM), which contributed for a better understanding of physical-chemical effects caused by ultrasound. After process optimization, a 4molL -1 HNO 3 solution, sonicated for 60min at 30°C in a cup horn system at 50% of amplitude, lead to 78% of conversion to furfural. This mild temperature condition combined to the use of a diluted acid solution represents an important contribution for the selective production of chemical building blocks using ultrasound energy. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Ultrasound-assisted extraction of rare-earth elements from carbonatite rocks.

    Science.gov (United States)

    Diehl, Lisarb O; Gatiboni, Thais L; Mello, Paola A; Muller, Edson I; Duarte, Fabio A; Flores, Erico M M

    2018-01-01

    In view of the increasing demand for rare-earth elements (REE) in many areas of high technology, alternative methods for the extraction of these elements have been developed. In this work, a process based on the use of ultrasound for the extraction of REE from carbonatite (an igneous rock) is proposed to avoid the use of concentrated reagents, high temperature and excessive extraction time. In this pioneer work for REE extraction from carbonatite rocks in a preliminary investigation, ultrasonic baths, cup horn systems or ultrasound probes operating at different frequencies and power were evaluated. In addition, the power released to the extraction medium and the ultrasound amplitude were also investigated and the temperature and carbonatite mass/volume of extraction solution ratio were optimized to 70°C and 20mg/mL, respectively. Better extraction efficiencies (82%) were obtained employing an ultrasound probe operating at 20kHz for 15min, ultrasound amplitude of 40% (692Wdm -3 ) and using a diluted extraction solution (3% v/v HNO 3 +2% v/v HCl). It is important to mention that high extraction efficiency was obtained even using a diluted acid mixture and relatively low temperature in comparison to conventional extraction methods for REE. A comparison of results with those obtained by mechanical stirring (500rpm) using the same conditions (time, temperature and extraction solution) was carried out, showing that the use of ultrasound increased the extraction efficiency up to 35%. Therefore, the proposed ultrasound-assisted procedure can be considered as a suitable alternative for high efficiency extraction of REE from carbonatite rocks. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Kinetics of Ultrasound-Assisted Flavonoid Extraction from Agri-Food Solid Wastes Using Water/Glycerol Mixtures

    Directory of Open Access Journals (Sweden)

    Dimitris P. Makris

    2016-01-01

    Full Text Available Red grape pomace (RGP and onion solid wastes (OSW were used as raw material to produce flavonoid-enriched extracts, using ultrasound-assisted solid-liquid extraction. The extraction medium used was composed of water and glycerol and under the conditions used the extraction of flavonoids from both materials was shown to obey first-order kinetics. Maximum diffusivities (De values were 4.01 × 10−11 and 2.35 × 10−11 m2·s−1, for RGP and OSW extraction, respectively, while the corresponding activation energies (Ea were 14.00 and 15.23 kJ·mol−1.

  5. Ecofriendly laccase-hydrogen peroxide/ultrasound-assisted bleaching of linen fabrics and its influence on dyeing efficiency.

    Science.gov (United States)

    Abou-Okeil, A; El-Shafie, A; El Zawahry, M M

    2010-02-01

    This study evaluates the bleaching efficiency of enzymatically scoured linen fabrics using a combined laccase-hydrogen peroxide bleaching process with and without ultrasonic energy, with the goal of obtaining fabrics with high whiteness levels, well preserved tensile strength and higher dye uptake. The effect of the laccase enzyme and the combined laccase-hydrogen peroxide bleaching process with and without ultrasound has been investigated with regard to whiteness value, tensile strength, dyeing efficiency and dyeing kinetics using both reactive and cationic dyes. The bleached linen fabrics were characterized using X-ray diffraction and by measuring tensile strength and lightness. The dyeing efficiency and kinetics were characterized by measuring dye uptake and colour fastness. The results indicated that ultrasound was an effective technique in the combined laccase-hydrogen peroxide bleaching process of linen fabrics. The whiteness values expressed as lightness of linen fabrics is enhanced by using ultrasonic energy. The measured colour strength values were found to be slightly better for combined laccase-hydrogen peroxide/ultrasound-assisted bleached fabrics than for combined laccase-hydrogen peroxide for both reactive and cationic dyes. The fastness properties of the fabrics dyed with reactive dye were better than those obtained when using cationic dye. The time/dye uptake isotherms were also enhanced when using combined laccase-hydrogen peroxide/ultrasound-assisted bleached fabric, which confirms the efficiency of ultrasound in the combined oxidative bleaching process. The dyeing rate constant, half-time of dyeing and dyeing efficiency have been calculated and discussed.

  6. Stability of Anthocyanins from Red Grape Skins under Pressurized Liquid Extraction and Ultrasound-Assisted Extraction Conditions

    Directory of Open Access Journals (Sweden)

    Ali Liazid

    2014-12-01

    Full Text Available The stability of anthocyanins from grape skins after applying different extraction techniques has been determined. The following compounds, previously extracted from real samples, were assessed: delphinidin 3-glucoside, cyanidin 3-glucoside, petunidin 3-glucoside, peonidin 3-glucoside, malvidin 3-glucoside, peonidin 3-acetylglucoside, malvidin 3-acetylglucoside, malvidin 3-caffeoylglucoside, petunidin 3-p-coumaroylglucoside and malvidin 3-p-coumaroylglucoside (trans. The techniques used were ultrasound-assisted extraction and pressurized liquid extraction. In ultrasound-assisted extraction, temperatures up to 75 °C can be applied without degradation of the aforementioned compounds. In pressurized liquid extraction the anthocyanins were found to be stable up to 100 °C. The relative stabilities of both the glycosidic and acylated forms were evaluated. Acylated derivatives were more stable than non-acylated forms. The differences between the two groups of compounds became more marked on working at higher temperatures and on using extraction techniques with higher levels of oxygen in the extraction media.

  7. Optimization of Ultrasound-Assisted Extraction of Natural Antioxidants from the Flower of Jatropha integerrima by Response Surface Methodology.

    Science.gov (United States)

    Xu, Dong-Ping; Zhou, Yue; Zheng, Jie; Li, Sha; Li, An-Na; Li, Hua-Bin

    2015-12-24

    An ultrasound-assisted extraction (UAE) method was developed for the efficient extraction of natural antioxidants from the flowers of Jatropha integerrima. Four independent variables, including ethanol concentration, solvent/material ratio, ultrasound irradiation time and temperature were studied by single factor experiments. Then, the central composite rotatable design and response surface methodology were employed to investigate the effect of three key parameters (ethanol concentration, solvent/material ratio, and ultrasound irradiation time) on the antioxidant activities of the flower extracts. The optimal extraction conditions were an ethanol concentration of 59.6%, solvent/material ratio of 50:1, ultrasound irradiation time of 7 min, and ultrasound irradiation temperature of 40 °C. Under these conditions, the optimized experimental value was 1103.38 ± 16.11 µmol Trolox/g dry weight (DW), which was in accordance with the predicted value (1105.49 µmol Trolox/g DW). Furthermore, the antioxidant activities of flower extracts obtained by UAE were compared with those produced by the traditional maceration and Soxhlet extraction methods, and UAE resulted in higher antioxidant activities after a shorter time at a lower temperature. The results obtained are helpful for the full utilization of Jatropha integerrima, and also indicate that ultrasound-assisted extraction is an efficient method for the extraction of natural antioxidants from plant materials.

  8. Optimization of Ultrasound-Assisted Extraction of Natural Antioxidants from the Flower of Jatropha integerrima by Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Dong-Ping Xu

    2015-12-01

    Full Text Available An ultrasound-assisted extraction (UAE method was developed for the efficient extraction of natural antioxidants from the flowers of Jatropha integerrima. Four independent variables, including ethanol concentration, solvent/material ratio, ultrasound irradiation time and temperature were studied by single factor experiments. Then, the central composite rotatable design and response surface methodology were employed to investigate the effect of three key parameters (ethanol concentration, solvent/material ratio, and ultrasound irradiation time on the antioxidant activities of the flower extracts. The optimal extraction conditions were an ethanol concentration of 59.6%, solvent/material ratio of 50:1, ultrasound irradiation time of 7 min, and ultrasound irradiation temperature of 40 °C. Under these conditions, the optimized experimental value was 1103.38 ± 16.11 µmol Trolox/g dry weight (DW, which was in accordance with the predicted value (1105.49 µmol Trolox/g DW. Furthermore, the antioxidant activities of flower extracts obtained by UAE were compared with those produced by the traditional maceration and Soxhlet extraction methods, and UAE resulted in higher antioxidant activities after a shorter time at a lower temperature. The results obtained are helpful for the full utilization of Jatropha integerrima, and also indicate that ultrasound-assisted extraction is an efficient method for the extraction of natural antioxidants from plant materials.

  9. Ultrasound-assisted extraction of natural antioxidants from the flower of Limonium sinuatum: Optimization and comparison with conventional methods.

    Science.gov (United States)

    Xu, Dong-Ping; Zheng, Jie; Zhou, Yue; Li, Ya; Li, Sha; Li, Hua-Bin

    2017-02-15

    Natural antioxidants are widely used as dietary supplements or food additives. An optimized method of ultrasound-assisted extraction (UAE) was proposed for the effective extraction of antioxidants from the flowers of Limonium sinuatum and evaluated by response surface methodology. In this study, ethanol concentration, ratio of solvent to solid, ultrasonication time and temperature were investigated and optimized using a central composite rotatable design. The optimum extraction conditions were as follows: ethanol concentration, 60%; ratio of solvent to solid, 56.9:1mL/g; ultrasonication time, 9.8min; and temperature, 40°C. Under the optimal UAE conditions, the experimental values (483.01±15.39μmolTrolox/gDW) matched with those predicted (494.13μmolTrolox/gDW) within a 95% confidence level. In addition, the antioxidant activities of UAE were compared with those of conventional maceration and Soxhlet extraction methods, and the ultrasound-assisted extraction could give higher yield of antioxidants and markedly reduce the extraction time. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Sequential Combination of Microwave- and Ultrasound-Assisted Extraction of Total Flavonoids from Osmanthus fragrans Lour. Flowers

    Directory of Open Access Journals (Sweden)

    Jianfeng Yu

    2017-12-01

    Full Text Available Microwave-assisted and ultrasound-assisted extraction assays were used to isolate total flavonoids (TF from Osmanthus fragrans flowers. The effects of the solid-liquid ratio, ethanol concentration, microwave power, microwave extraction time, ultrasonic power and ultrasonic extraction time on the yield of TF were studied. A sequential combination of microwave- and ultrasound-assisted extraction (SC-MUAE methods was developed, which was subsequently optimized by Box-Behnken design-response surface methodology (BBD-RSM. The interaction effects of the ethanol concentration (40–60%, microwave extraction time (5–7 min, ultrasonic extraction time (8–12 min and ultrasonic power (210–430 W on the yield of TF were investigated. The optimum operating parameters for the extraction of TF were determined to be as follows: ethanol concentration (48.15%, microwave extraction time (6.43 min, ultrasonic extraction time (10.09 min and ultrasonic power (370.9 W. Under these conditions, the extraction yield of TF was 7.86 mg/g.

  11. Optimization and Comparison of Ultrasound-Assisted Extraction of Estragole from Tarragon Leaves with Hydro-Distillation Method

    Directory of Open Access Journals (Sweden)

    Mohammad Bagher Gholivand

    2014-12-01

    Full Text Available A comparative study of ultrasound-assisted extraction (UAE and hydro-distillation was performed for fast extraction of estragole from tarragon (Artemisia dracunculus L. dried leaves. Several influential parameters of the UAE procedure in the extraction of estragole (type of solvent, extraction cycles, solvent to material ratio, irradiation time and particle size were investigated and optimized. It was found that UAE offers a more rapid extraction of estragole than hydrodistillation. The optimum parameters were solvent to material ratio of 8:1 v/m, 96% (w/w ethanol in water as extraction solvent, particle size of 1.18 mm, irradiation time of 5 min, output power of 63 W, 9 pulses, and ultrasonic frequency of 20 kHz. The recovery of estragole by UAE under optimal conditions was 44.4% based on dry extract. The benefit of ultrasound was to decrease the extraction time (5 min relative to the classical hydrodistillation method (3 h. The experimental results also indicated that ultrasound-assisted extraction is a simple, rapid and effective method for extraction of the volatile oil components of tarragon.

  12. Optimization of enzymes-microwave-ultrasound assisted extraction of Lentinus edodes polysaccharides and determination of its antioxidant activity.

    Science.gov (United States)

    Yin, Chaomin; Fan, Xiuzhi; Fan, Zhe; Shi, Defang; Gao, Hong

    2018-05-01

    Enzymes-microwave-ultrasound assisted extraction (EMUE) method had been used to extract Lentinus edodes polysaccharides (LEPs). The enzymatic temperature, enzymatic pH, microwave power and microwave time were optimized by response surface methodology. The yields, properties and antioxidant activities of LEPs from EMUE and other extraction methods including hot-water extraction, enzymes-assisted extraction, microwave-assisted extraction and ultrasound-assisted extraction were evaluated. The results showed that the highest LEPs yield of 9.38% was achieved with enzymatic temperature of 48°C, enzymatic pH of 5.0, microwave power of 440W and microwave time of 10min, which correlated well with the predicted value of 9.79%. Additionally, LEPs from different extraction methods possessed typical absorption peak of polysaccharides, which meant different extraction methods had no significant effects on type of glycosidic bonds and sugar ring of LEPs. However, SEM images of LEPs from different extraction methods were significantly different. Moreover, the different LEPs all showed antioxidant activities, but LEPs from EMUE showed the highest reducing power when compared to other LEPs. The results indicated LEPs from EMUE can be used as natural antioxidant component in the pharmaceutical and functional food industries. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. Green ultrasound-assisted extraction of anthocyanin and phenolic compounds from purple sweet potato using response surface methodology

    Science.gov (United States)

    Zhu, Zhenzhou; Guan, Qingyan; Guo, Ying; He, Jingren; Liu, Gang; Li, Shuyi; Barba, Francisco J.; Jaffrin, Michel Y.

    2016-01-01

    Response surface methodology was used to optimize experimental conditions for ultrasound-assisted extraction of valuable components (anthocyanins and phenolics) from purple sweet potatoes using water as a solvent. The Box-Behnken design was used for optimizing extraction responses of anthocyanin extraction yield, phenolic extraction yield, and specific energy consumption. Conditions to obtain maximal anthocyanin extraction yield, maximal phenolic extraction yield, and minimal specific energy consumption were different; an overall desirability function was used to search for overall optimal conditions: extraction temperature of 68ºC, ultrasonic treatment time of 52 min, and a liquid/solid ratio of 20. The optimized anthocyanin extraction yield, phenolic extraction yield, and specific energy consumption were 4.91 mg 100 g-1 fresh weight, 3.24 mg g-1 fresh weight, and 2.07 kWh g-1, respectively, with a desirability of 0.99. This study indicates that ultrasound-assisted extraction should contribute to a green process for valorization of purple sweet potatoes.

  14. Nano-coating of beta-galactosidase onto the surface of lactose by using an ultrasound-assisted technique

    DEFF Research Database (Denmark)

    Genina, Natalja; Räikkönen, Heikki; Heinämäki, Jyrki

    2010-01-01

    We nano-coated powdered lactose particles with the enzyme beta-galactosidase using an ultrasound-assisted technique. Atomization of the enzyme solution did not change its activity. The amount of surface-attached beta-galactosidase was measured through its enzymatic reaction product D-galactose us......We nano-coated powdered lactose particles with the enzyme beta-galactosidase using an ultrasound-assisted technique. Atomization of the enzyme solution did not change its activity. The amount of surface-attached beta-galactosidase was measured through its enzymatic reaction product D......-galactose using a standardized method. A near-linear increase was obtained in the thickness of the enzyme coat as the treatment proceeded. Interestingly, lactose, which is a substrate for beta-galactosidase, did not undergo enzymatic degradation during processing and remained unchanged for at least 1 month....... Stability of protein-coated lactose was due to the absence of water within the powder, as it was dry after the treatment procedure. In conclusion, we were able to attach the polypeptide to the core particles and determine precisely the coating efficiency of the surface-treated powder using a simple approach....

  15. Vibrational Spectroscopy of Ionic Liquids.

    Science.gov (United States)

    Paschoal, Vitor H; Faria, Luiz F O; Ribeiro, Mauro C C

    2017-05-24

    Vibrational spectroscopy has continued use as a powerful tool to characterize ionic liquids since the literature on room temperature molten salts experienced the rapid increase in number of publications in the 1990's. In the past years, infrared (IR) and Raman spectroscopies have provided insights on ionic interactions and the resulting liquid structure in ionic liquids. A large body of information is now available concerning vibrational spectra of ionic liquids made of many different combinations of anions and cations, but reviews on this literature are scarce. This review is an attempt at filling this gap. Some basic care needed while recording IR or Raman spectra of ionic liquids is explained. We have reviewed the conceptual basis of theoretical frameworks which have been used to interpret vibrational spectra of ionic liquids, helping the reader to distinguish the scope of application of different methods of calculation. Vibrational frequencies observed in IR and Raman spectra of ionic liquids based on different anions and cations are discussed and eventual disagreements between different sources are critically reviewed. The aim is that the reader can use this information while assigning vibrational spectra of an ionic liquid containing another particular combination of anions and cations. Different applications of IR and Raman spectroscopies are given for both pure ionic liquids and solutions. Further issues addressed in this review are the intermolecular vibrations that are more directly probed by the low-frequency range of IR and Raman spectra and the applications of vibrational spectroscopy in studying phase transitions of ionic liquids.

  16. Optimization of ultrasound-assisted dispersive solid-phase microextraction based on nanoparticles followed by spectrophotometry for the simultaneous determination of dyes using experimental design.

    Science.gov (United States)

    Asfaram, Arash; Ghaedi, Mehrorang; Goudarzi, Alireza

    2016-09-01

    A simple, low cost and ultrasensitive method for the simultaneous preconcentration and determination of trace amount of auramine-O and malachite green in aqueous media following accumulation on novel and lower toxicity nanomaterials by ultrasound-assisted dispersive solid phase micro-extraction (UA-DSPME) procedure combined with spectrophotometric has been described. The Mn doped ZnS nanoparticles loaded on activated carbon were characterized by Field emission scanning electron microscopy (FE-SEM), particle size distribution, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) analyses and subsequently were used as green and efficient material for dyes accumulation. Contribution of experimental variables such as ultrasonic time, ultrasonic temperature, adsorbent mass, vortex time, ionic strength, pH and elution volume were optimized through experimental design, and while the preconcentrated analytes were efficiently eluted by acetone. Preliminary Plackett-Burman design was applied for selection of most significant factors and giving useful information about their main and interaction part of significant variables like ultrasonic time, adsorbent mass, elution volume and pH were obtained by central composite design combined with response surface analysis and optimum experimental conditions was set at pH of 8.0, 1.2mg of adsorbent, 150μL eluent and 3.7min sonication. Under optimized conditions, the average recoveries (five replicates) for two dyes (spiked at 500.0ngmL(-1)) changes in the range of 92.80-97.70% with acceptable RSD% less than 4.0% over a linear range of 3.0-5000.0ngmL(-1) for the AO and MG in water samples with regression coefficients (R(2)) of 0.9975 and 0.9977, respectively. Acceptable limits of detection of 0.91 and 0.61ngmL(-1) for AO and MG, respectively and high accuracy and repeatability are unique advantages of present method to improve the figures of merit for their accurate determination at trace level in complicated

  17. The Use of Response Surface Methodology to Optimize the Ultrasound-Assisted Extraction of Five Anthraquinones from Rheum palmatum L.

    Directory of Open Access Journals (Sweden)

    Xianghua Xia

    2011-07-01

    Full Text Available In this paper, ultrasound-assisted extraction (UAE was applied to the extraction of anthraquinones (aloe-emodin, rhein, emodin, chrysophanol and physcion from Rheum palmatum L. The five anthraquinones were quantified and analyzed by high performance liquid chromatography coupled with UV detection (HPLC-UV. The extraction solvent, extraction temperature and extraction time parameters, the three main factors for UAE, were optimized with response surface methodology (RSM to obtain the highest extraction efficiency. The optimal conditions were the use of 84% methanol as solvent, an extraction time of 33 min and an extraction temperature of 67 °C. Under these optimal conditions, the experimental values agreed closely with the predicted values. The analysis of variance indicated a high goodness of model fit and the success of RSM method for optimizing anthraquinones extraction in Rheum palmatum L.

  18. Recovery and purification of cholesterol from cholesterol-β-cyclodextrin inclusion complex using ultrasound-assisted extraction.

    Science.gov (United States)

    Li, Yong; Chen, Youliang; Li, Hua

    2017-01-01

    Response surface methodology was used to optimize ultrasound-assisted ethanol extraction (UAE) of cholesterol from cholesterol-β-cyclodextrin (C-β-CD) inclusion complex prepared from duck yolk oil. The best extraction conditions were solvent-solid ratio 10mL/g, ultrasonic power 251W, extraction temperature 56°C and sonication time 36min. Under these conditions, the highest cholesterol extraction yield and cholesterol content obtained 98.12±0.25% and 43.38±0.61mg/g inclusion complex, respectively. As compared with Reflux extraction and Soxhlet extraction, the UAE was more efficient and economical. To increase the purity of crude cholesterol extraction, silica gel column chromatography and crystallization were carried out. Finally, cholesterol was obtained at 95.1% purity, 71.7% recovery and 22.0% yield. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Ultrasound assisted arthroscopic approach for removal of basilar sesamoid fragments of the proximal sesamoid bones in horses.

    Science.gov (United States)

    Barrett, Elizabeth J; Rodgerson, Dwayne H

    2014-08-01

    To describe an ultrasound assisted arthroscopic approach for removal of non-articular basilar sesamoid fragments in Thoroughbred yearlings. Thoroughbred yearlings (n = 7). Basilar sesamoid fragments identified during pre-sale radiographic examination were removed using a palmar/plantar arthroscopic approach to the fetlock joint and ultrasonographic guidance. Complete fragment removal was confirmed by ultrasonography and radiography. Basilar sesamoid fracture fragments were localized and removed successfully using rongeurs and a radiofrequency probe for soft tissue dissection of the fragment. Complete fragment removal was confirmed by ultrasonography and radiography. No intra- or postoperative complications occurred. At 6-8 months follow-up, no fragments or bony proliferation at the base of the sesamoid was observed. Ultrasonographic guidance can be used to facilitate localization, dissection, and confirmation of removal of basilar fragments of the proximal sesamoid bone. © Copyright 2014 by The American College of Veterinary Surgeons.

  20. Phase structuring in metal alloys: Ultrasound-assisted top-down approach to engineering of nanostructured catalytic materials.

    Science.gov (United States)

    Cherepanov, Pavel V; Andreeva, Daria V

    2017-03-01

    High intensity ultrasound (HIUS) is a novel and efficient tool for top-down nanostructuring of multi-phase metal systems. Ultrasound-assisted structuring of the phase in metal alloys relies on two main mechanisms including interfacial red/ox reactions and temperature driven solid state phase transformations which affect surface composition and morphology of metals. Physical and chemical properties of sonication medium strongly affects the structuring pathways as well as morphology and composition of catalysts. HIUS can serve as a simple, fast, and effective approach for the tuning of structure and surface properties of metal particles, opening the new perspectives in design of robust and efficient catalysts. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Influencing factors and kinetics analysis on the leaching of iron from boron carbide waste-scrap with ultrasound-assisted method.

    Science.gov (United States)

    Li, Xin; Xing, Pengfei; Du, Xinghong; Gao, Shuaibo; Chen, Chen

    2017-09-01

    In this paper, the ultrasound-assisted leaching of iron from boron carbide waste-scrap was investigated and the optimization of different influencing factors had also been performed. The factors investigated were acid concentration, liquid-solid ratio, leaching temperature, ultrasonic power and frequency. The leaching of iron with conventional method at various temperatures was also performed. The results show the maximum iron leaching ratios are 87.4%, 94.5% for 80min-leaching with conventional method and 50min-leaching with ultrasound assistance, respectively. The leaching of waste-scrap with conventional method fits the chemical reaction-controlled model. The leaching with ultrasound assistance fits chemical reaction-controlled model, diffusion-controlled model for the first stage and second stage, respectively. The assistance of ultrasound can greatly improve the iron leaching ratio, accelerate the leaching rate, shorten leaching time and lower the residual iron, comparing with conventional method. The advantages of ultrasound-assisted leaching were also confirmed by the SEM-EDS analysis and elemental analysis of the raw material and leached solid samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. An ultrasound-assisted digestion method for the determination of toxic element concentrations in ash samples by inductively coupled plasma optical emission spectrometry

    International Nuclear Information System (INIS)

    Ilander, Aki; Vaeisaenen, Ari

    2007-01-01

    A method of ultrasound-assisted digestion followed by inductively coupled plasma optical emission spectrometry (ICP-OES) used for the determination of toxic element concentrations (arsenic, barium, cobalt, copper, lead, nickel, strontium, vanadium and zinc) in ash samples was developed. All the measurements were performed in robust plasma conditions which were tested by measuring the Mg(II) 280.270 nm/Mg(I) 285.213 nm line intensity ratios. The highest line intensity ratios were observed when a nebulizer gas flow of 0.6 L min -1 , auxiliary gas flow of 0.2 L min -1 and plasma power of 1400 W were used for radially viewed plasma. The analysis of SRM 1633b showed that the ultrasound-assisted method developed is highly comparable with the microwave digestion method standardized by the United States Environmental Protection Agency (EPA-3052). The ultrasound-assisted digestion with a digestion solution of aqua regia and hydrofluoric acid (HF) resulted in recovery rates of over 81%. One exception is arsenic which resulted in recoveries of about 60% only; however, it could be digested with good recovery (>90%) using a digestion solution of 5 mL of water and 5 mL of aqua regia. The major advantage of the ultrasound-assisted digestion over microwave digestion is the high treatment rate (30 samples simultaneously with a sonication time of 18 min)

  3. Ultrasound assisted synthesis of ZnO/reduced graphene oxide composites with enhanced photocatalytic activity and anti-photocorrosion

    International Nuclear Information System (INIS)

    Peng, Yonggang; Ji, Junling; Chen, Dajun

    2015-01-01

    Graphical abstract: - Highlights: • ZnO/reduced graphene oxide composites were prepared by in situ growth with ultrasound assisted method. • A plausible formation mechanism of ZnO/rGO composites was deduced. • After hybridization with rGO, the photocatalytic activity of ZnO was improved and its photocorrosion was inhibited obviously. - Abstract: A method to improve the photocatalytic activity and suppress the photocorrosion of ZnO was developed by depositing ZnO nanoparticles onto the surface of reduced graphene oxide (rGO) via in situ growth with ultrasound assisted synthesis. The optimum synergetic effect of ZnO/rGO composite was found at a weight ratio of 2% (rGO/ZnO). Compared with ZnO, the photocatalytic activities of ZnO/rGO composite for the degradation of methylene blue (MB) and C.I. acid red 249 (AR249) aqueous solutions under UV light irradiation were increased by 8.6% and 14.7%, respectively. The improved photocatalytic activity was originated from the rapid separation of photogenerated electrons and holes on the interface of rGO and ZnO. The photocorrosion of ZnO was inhibited obviously after hybridization with rGO. Even after six successive cycles under UV irradiation, the photocatalytic activities of ZnO/rGO composite for MB and AR249 still retained 92.9% and 94.8% of that for the first cycling run, while that of ZnO obviously decreased due to serious photocorrosion. The photocorrosion inhibition of ZnO by rGO was attributed to the reduced activation of surface oxygen atom on the surface of ZnO.

  4. Mechanistic study on ultrasound assisted pretreatment of sugarcane bagasse using metal salt with hydrogen peroxide for bioethanol production.

    Science.gov (United States)

    Ramadoss, Govindarajan; Muthukumar, Karuppan

    2016-01-01

    This study presents the ultrasound assisted pretreatment of sugarcane bagasse (SCB) using metal salt with hydrogen peroxide for bioethanol production. Among the different metal salts used, maximum holocellulose recovery and delignification were achieved with ultrasound assisted titanium dioxide (TiO2) pretreatment (UATP) system. At optimum conditions (1% H2O2, 4 g SCB dosage, 60 min sonication time, 2:100 M ratio of metal salt and H2O2, 75°C, 50% ultrasound amplitude and 70% ultrasound duty cycle), 94.98 ± 1.11% holocellulose recovery and 78.72 ± 0.86% delignification were observed. The pretreated SCB was subjected to dilute acid hydrolysis using 0.25% H2SO4 and maximum xylose, glucose and arabinose concentration obtained were 10.94 ± 0.35 g/L, 14.86 ± 0.12 g/L and 2.52 ± 0.27 g/L, respectively. The inhibitors production was found to be very less (0.93 ± 0.11 g/L furfural and 0.76 ± 0.62 g/L acetic acid) and the maximum theoretical yield of glucose and hemicellulose conversion attained were 85.8% and 77%, respectively. The fermentation was carried out using Saccharomyces cerevisiae and at the end of 72 h, 0.468 g bioethanol/g holocellulose was achieved. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis of pretreated SCB was made and its morphology was studied using scanning electron microscopy (SEM). The compounds formed during the pretreatment were identified using gas chromatography-mass spectrometry (GC-MS) analysis. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Surface modification of chitin using ultrasound-assisted and supercritical CO{sub 2} technologies for cobalt adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Dotto, Guilherme L., E-mail: guilherme_dotto@yahoo.com.br; Cunha, Jeanine M., E-mail: jeaninecunha@gmail.com; Calgaro, Camila O., E-mail: camila.itepjr@gmail.com; Tanabe, Eduardo H., E-mail: edutanabe@yahoo.com.br; Bertuol, Daniel A., E-mail: dbertuol@gmail.com

    2015-09-15

    Highlights: • Chitin was modified by ultrasound-assisted (UA) and supercritical (SCO{sub 2}) technologies. • Chitin, UA-chitin and SCO{sub 2}-chitin were used as adsorbents for Co(II). • UA and SCO{sub 2} treatments provided increase of 20 and 3 times in chitin surface area. • The Co(II) adsorption capacity increased until 67.8%, using UA-chitin. - Abstract: Ultrasound-assisted (UA) and supercritical CO{sub 2} technologies (SCO{sub 2}) were used to modify the chitin surface and, improve its adsorption characteristics regarding to cobalt. Chitin, before and after the treatments, was characterized by N{sub 2} adsorption isotherms (BET), infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Unmodified and surface modified chitins were used as adsorbents to remove cobalt from aqueous solutions. The adsorption study was performed by equilibrium isotherms and kinetic curves. The chitin particle characteristics, such as, surface area, pore volume and porosity were improved by the UA and SCO{sub 2} treatments. The crystallinity index decreased after the UA and SCO{sub 2} treatments, and also, intense surface modifications were observed. Langmuir and Freundlich models were adequate to represent the adsorption equilibrium. The maximum adsorption capacities were 50.03, 83.94 and 63.08 mg g{sup −1} for unmodified chitin, UA surface modified chitin and SCO{sub 2} surface modified chitin. The adsorption kinetic curves were well represented by the pseudo-second order model. UA and SCO{sub 2} technologies are alternatives to modify the chitin surface and improve its adsorption characteristics.

  6. Ultrasound-assisted extraction of lipids from Chlorella vulgaris using [Bmim][MeSO4

    International Nuclear Information System (INIS)

    Kim, Young-Hoo; Park, Saerom; Kim, Min Hoo; Choi, Yong-Keun; Yang, Yung-Hun; Kim, Hyung Joo; Kim, Hyungsup; Kim, Han-Soo; Song, Kyung-Guen; Lee, Sang Hyun

    2013-01-01

    Lipids from Chlorella vulgaris were successfully extracted using an ionic liquid, [Bmim][MeSO 4 ]. [Bmim][MeSO 4 ] dissolved C. vulgaris, leaving the lipids insoluble. The undissolved lipids could easily be recovered due to the lower density of the lipid phase. Furthermore, ultrasound irradiation highly enhanced the extraction rate and yield with [Bmim][MeSO 4 ]. The total amounts of lipid extracted from C. vulgaris by the Soxhlet method and the Bligh and Dyer's method were 21 and 29 mg/g dry cell weight (DCW), respectively, whereas it was 47 mg/g DCW with [Bmim][MeSO 4 ]. Additionally, the amount of lipid extracted using [Bmim][MeSO 4 ] was 1.6 times greater with ultrasound irradiation. The rate of extraction of lipids from C. vulgaris with [Bmim][MeSO 4 ] was also 2.7 times greater with ultrasound irradiation. The fatty acid profiles of the lipids extracted using [Bmim][MeSO 4 ] were very similar to those of the lipids obtained by Bligh and Dyer's method. -- Highlights: •[Bmim][MeSO 4 ] efficiently extracted lipids from algae without pretreatment. •Ultrasound irradiation highly enhanced the extraction rate and yield of the extraction system using IL. •Fatty acid profiles of lipids extracted using [Bmim][MeSO 4 ] were similar to those of the lipids obtained by conventional methods

  7. Ultrasound-assisted lipase-catalyzed synthesis of D-isoascorbyl palmitate: process optimization and Kinetic evaluation.

    Science.gov (United States)

    Cui, Feng-Jie; Zhao, Hong-Xia; Sun, Wen-Jing; Wei, Zhuan; Yu, Si-Lian; Zhou, Qiang; Dong, Ying

    2013-12-09

    D-isoascorbic acid is a food antioxidant additive and used in accordance with Good Manufacturing Practice (GMP). High solubility in water (about 150 g/L at 25°C) reduces its effectiveness in stabilizing fats and oils. Our research group had successfully synthesized D-isoascorbyl palmitate using immobilized lipase Novozym 435 as a biocatalyst. Low production efficiency of D-isoascorbyl palmitate is still a problem for industrial production due to the long reaction time of over 24 h. In the present work, ultrasonic treatment was applied for accelerating the reaction process. The operation parameters were optimized to obtain the maximum D-isoascorbyl palmitate conversion rate by using a 5-level-4-factor Central Composite Design (CCD) and Response Surface Methdology (RSM). The reaction apparent kinetic parameters under the ultrasound treatment and mechanical shaking conditions were also determined and compared. Results showed that ultrasound treatment decreased the reaction time by over 50%. D-isoascorbyl palmitate yielded to 94.32 ± 0.17% and the productivity reached to 8.67 g L-1 h-1 under the optimized conditions as: 9% of enzyme load (w/w), 61°C of reaction temperature, 1:5 of D- isoascorbic-to-palmitic acid molar ratio, and 137 W of the ultrasound power. The immobilized lipase Novozym 435 could be reused for 7 times with 65% of the remained D-isoascorbyl palmitate conversion rate. The reaction kinetics showed that the maximum apparent reaction rate (vmax) of the ultrasound-assisted reaction was 2.85 times higher than that of the mechanical shaking, which proved that ultrasound treatment significantly enhanced the reaction efficiency. A systematic study on ultrasound-assisted enzymatic esterification for D-isoascorbyl palmitate production is reported. The results show a promising perspective of the ultrasound technique to reduce the reaction time and improve the production efficiency. The commercial D-isoascorbyl palmitate synthesis will be potentially

  8. Ultrasound assisted synthesis of stable oil in milk emulsion: Study of operating parameters and scale-up aspects.

    Science.gov (United States)

    Patil, Leena; Gogate, Parag R

    2018-01-01

    In the present work, application of ultrasound and stirring individually or in combination for improved emulsification of turmeric oil in skimmed milk has been investigated. The effect of different operating parameters/strategies such as addition of surfactant, sodium dodecyl sulfate (SDS), at different concentrations, quantity of oil phase, applied power, sonication time and duty cycle on the droplet size have been investigated. The stability of emulsion was analyzed in terms of the fraction of the emulsion that remains stable for a period of 28days. Optimized set of major emulsification process variables has been used at higher emulsion volumes. The effectiveness of treatment approach was analyzed based on oil droplet size, energy density and the time required for the formation of stable emulsion. It was observed that the stable emulsion at 50mL capacity with mean droplet diameter of about 235.4nm was obtained with the surfactant concentration of 5mg/mL, 11% of rated power (power density: 0.31W/mL) and irradiation time of 5min. The emulsion stability was higher in the case of ultrasound assisted approach as compared to the stirring. For the preparation of stable emulsion at 300mL capacity, it was observed that the sequential approach, i.e., stirring followed by ultrasound, gave lower mean droplet diameter (232.6nm) than the simultaneous approach, i.e., ultrasound and stirring together (257.9nm). However, the study also revealed that the simultaneous approach required very less time (15min) to synthesize stable emulsion as compared to the sequential approach (30min stirring and 60min ultrasound). It was successfully demonstrated that the ultrasound-assisted emulsification in the presence of SDS could be used for the preparation of stable turmeric oil-dairy emulsions, also providing insights into the role of SDS in increasing the stability of emulsions and of ultrasound in giving lower droplet sizes. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Ultrasound assisted extraction of natural dye from jackfruit's wood (Artocarpus heterophyllus): The effect of ethanol concentration as a solvent

    Science.gov (United States)

    Febriana, Ike Dayi; Gala, Selfina; Mahfud, Mahfud

    2017-05-01

    Azo dye are synthetic organic dyes which has an azo group (- N = N -) as chromophore. Azo dye is resistand to decomposition process and harmfull for the environment and human being. Natural dye can be used as substitution of azo dye at textile industry. Natural dye are eco - friendly and can be applied for dyeing of fibrous material. Natural dye can be obtained from natural origin such as leaves, wood, or roots. The wood of jackfruit (Artocarpus heterophyllus) can used as natural source of natural dye. Ultrasound assisted extraction (UAE) is a new method that can be used to extract natural dye from jackfruit's wood. The aim of this research are to study about influence of ethanol concentration as solvent and extraction kinetic. Jackfruit's wood dust from sawmill used for the experimentation were sifted by sieve 35 mesh. Ethanol 96% used as solvent of this experiment and varied the concentration in volume to volume ratio (v/v). Experiment were carried out from 20 to 50 minutes. The result of this experiment shows that ethanol concentration influenced yield of extraction from jackfruit's wood. Concentration of ethanol will be affected polarity of solvent. The Peleg model was used to describe about kinetic model of natural dye extraction. Value of k1 and k2 constant are 0.003835 and 0.04186 respectively.

  10. Optimization of Ultrasound-Assisted Extraction of Antioxidants from Apium graveolens L. Seeds using Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Şule Dinç Zor

    2017-09-01

    Full Text Available In this study, optimum conditions for ultrasound-assisted extraction (UAE of antioxidants from Apium graveolens L. seeds were investigated by Response Surface Methodology (RSM. A Box-Behnken Design (BBD was used to evaluate the effect of sonication time (5, 10, 15 min, ultrasound power (60, 120, 180 W and the ratio of extraction solvent in terms of methanol (0, 50, 100% on antioxidant capacity. The optimal UAE conditions for the parameters investigated were 11 min of sonication time, ultrasound power of 131 W and 100% methanol as an extraction solvent. Under these conditions, UAE of antioxidants from the seeds achieved a maximum of 95.08% in respect to 1,1-diphenyl-2-picryl hydrazyl (DPPH radical scavenging activity. Additionally, the high value of the adjusted coefficient of determination (R2adj = 0.9192 and the non-significant difference between experimental and predicted values confirmed the validity of the quadratic polynomial model. Hence, UAE is a suitable, fast, economical and practical technique for the extraction of antioxidants from Apium graveolens L. seeds.

  11. Ultrasound-assisted HCl-NaCl leaching of lead-rich and antimony-rich oxidizing slag.

    Science.gov (United States)

    Zhang, Rong Liang; Zhang, Xiao Fei; Tang, Shu Zhen; Huang, Ai Dong

    2015-11-01

    Lead-rich and antimony-rich oxidizing slag was subjected to regular HCl-NaCl leaching, with the experimental conditions optimized under which ultrasound was introduced. After only 15 min of ultrasound-assisted leaching, the leaching rate of Sb resembled that after 45 min of regular leaching. Ultrasonic treatment considerably elevated the leaching rates of Sb and Pb, and shortened the leaching time. With the decrease of particle size, the leaching rate of Sb and Pb increased gradually. Especially, as the particle size of the slag was greater than 0.217 mm, the ultrasonic leaching effects of Sb and Pb were significantly higher than that of regular leaching effects. The temperature exhibited great effect on ultrasonic leaching performance. As the temperature increased, the leaching rates of Sb and Pb increased step by step. In case the temperature was higher than 85°C, the increasing speed of the leaching rates for Sb and Pb tended to be slow. Increasing ultrasonic power could augment the leaching rate or accelerate the procedure till the same leaching rate. However, since ultrasound failed to energize the formation of new reaction pathways, the maximum leaching rates of Sb and Pb were determined by their phase compositions rather than by ultrasonic field. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Multivariate optimization of an ultrasound-assisted extraction procedure for Cu, Mn, Ni and Zn determination in ration to chickens

    Directory of Open Access Journals (Sweden)

    JOELIA M. BARROS

    2013-09-01

    Full Text Available In this work, multivariate optimization techniques were used to develop a method based on the ultrasound-assisted extraction for copper, manganese, nickel and zinc determination from rations for chicken nutrition using flame atomic absorption spectrometry. The proportions of extracting components (2.0 mol.L–1 nitric, hydrochloric and acetic acid solutions were optimized using centroid-simplex mixture design. The optimum proportions of this mixture taken as percentage of each component were respectively 20%, 37% and 43%. Variables of method (sample mass, sonication time and final acid concentration were optimized using Doehlert design. The optimum values found for these variables were respectively 0.24 g, 18s and 3.6 mol.L–1. The developed method allows copper, manganese, nickel and zinc determination with quantification limits of 2.82; 4.52; 10.7; e 9.69 µg.g–1, and precision expressed as relative standard deviation (%RSD, 25 µg.g–1, N = 5 of 5.30; 2.13; 0.88; and 0.83%, respectively. This method was applied in the analytes determination from chicken rations collected from specialized commerce in Jequié city (Bahia State/Brazil. Application of paired t-test at the obtained results, in a confidence level of 95%, does not show significant difference between the proposed method and the microwave-assisted digestion.

  13. Development and validation of an efficient ultrasound assisted extraction of phenolic compounds from flax (Linum usitatissimum L.) seeds.

    Science.gov (United States)

    Corbin, Cyrielle; Fidel, Thibaud; Leclerc, Emilie A; Barakzoy, Esmatullah; Sagot, Nadine; Falguiéres, Annie; Renouard, Sullivan; Blondeau, Jean-Philippe; Ferroud, Clotilde; Doussot, Joël; Lainé, Eric; Hano, Christophe

    2015-09-01

    Flaxseed accumulates in its seedcoat a macromolecular complex composed of lignan (secoisolariciresinol diglucoside, SDG), flavonol (herbacetin diglucoside, HDG) and hydroxycinnamic acids (p-couramic, caffeic and ferulic acid glucosides). Their antioxidant and/or cancer chemopreventive properties support their interest in human health and therefore, the demand for their extraction. In the present study, ultrasound-assisted extraction (UAE) of flaxseed phenolic compounds was investigated. Scanning Electron Microscopy imaging and histochemical analysis revealed the deep alteration of the seedcoat ultrastructure and the release of the mucilage following ultrasound treatment. Therefore, this method was found to be very efficient for the reduction of mucilage entrapment of flaxseed phenolics. The optimal conditions for UAE phenolic compounds extraction from flaxseeds were found to be: water as solvent supplemented with 0.2N of sodium hydroxide for alkaline hydrolysis of the SDG-HMG complex, an extraction time of 60 min at a temperature of 25°C and an ultrasound frequency of 30 kHz. Under these optimized and validated conditions, highest yields of SDG, HDG and hydroxycinnamic acid glucosides were detected in comparison to other published methods. Therefore, the procedure presented herein is a valuable method for efficient extraction and quantification of the main flaxseed phenolics. Moreover, this UAE is of particular interest within the context of green chemistry in terms of reducing energy consumption and valuation of flaxseed cakes as by-products resulting from the production of flax oil. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Morphologic, magnetic, and Moessbauer spectral properties of Fe75Co25 nanoparticles prepared by ultrasound-assisted electrochemistry

    International Nuclear Information System (INIS)

    Mancier, Valerie; Delplancke, J.-L.; Delwiche, Jacques; Hubin-Franskin, M.-J.; Piquer, Cristina; Rebbouh, Leila; Grandjean, Fernande

    2004-01-01

    Nanopowders of Fe 75 Co 25 alloys have been prepared by ultrasound-assisted electrochemistry. Their composition, crystallographic structure, morphology, have been studied by X-ray diffraction, transmission electron microscopy, X-ray fluorescence, and high-energy electron diffraction. The nanopowders are found to present a composition well determined by the electrolyte bath composition, they show a bcc structure. The iron and cobalt atoms exhibit a very homogeneous distribution in the particles. The magnetic properties of the nanopowders have been measured between 5 and 295 K with a vibrating sample magnetometer and their Moessbauer spectra have been obtained at 295 K. The saturation magnetization is characteristic of FeCo alloys. The magnetic behavior and transmission electron microscopy observations of the particles indicate strongly interacting particles with a radius of ca. 2-4 nm, particles which may form agglomerates of larger size. The measured average hyperfine field is situated at the maximum of the Slater-Pauling curve for the FeCo alloys

  15. Determination of Oleanolic and Ursolic Acids in Hedyotis diffusa Using Hyphenated Ultrasound-Assisted Supercritical Carbon Dioxide Extraction and Chromatography

    Directory of Open Access Journals (Sweden)

    Ming-Chi Wei

    2015-01-01

    Full Text Available Oleanolic acid (OA and ursolic acid (UA were extracted from Hedyotis diffusa using a hyphenated procedure of ultrasound-assisted and supercritical carbon dioxide (HSC–CO2 extraction at different temperatures, pressures, cosolvent percentages, and SC–CO2 flow rates. The results indicated that these parameters significantly affected the extraction yield. The maximal yields of OA (0.917 mg/g of dry plant and UA (3.540 mg/g of dry plant were obtained at a dynamic extraction time of 110 min, a static extraction time of 15 min, 28.2 MPa, and 56°C with a 12.5% (v/v cosolvent (ethanol/water = 82/18, v/v and SC–CO2 flowing at 2.3 mL/min (STP. The extracted yields were then analyzed by high performance liquid chromatography (HPLC to quantify the OA and UA. The present findings revealed that H. diffusa is a potential source of OA and UA. In addition, using the hyphenated procedure for extraction is a promising and alternative process for recovering OA and UA from H. diffusa at high concentrations.

  16. Extraction Optimization, Characterization, and Bioactivities of Polysaccharides from Pinelliae Rhizoma Praeparatum Cum Alumine Employing Ultrasound-Assisted Extraction.

    Science.gov (United States)

    Liu, Yu-Jie; Mo, Xue-Lin; Tang, Xiao-Zhang; Li, Jiang-Hua; Hu, Mei-Bian; Yan, Dan; Peng, Wei; Wu, Chun-Jie

    2017-06-09

    In this study, the ultrasound-assisted extraction of polysaccharides (PSA) from Pinelliae Rhizoma Praeparatum Cum Alumine (PRPCA) was optimized by response surface methodology (RSM). The structural characteristics of PSA were analyzed by UV-vis spectroscopy, infrared spectroscopy, scanning electron microscopy, high performance gel permeation chromatography and high performance liquid chromatography, respectively. In addition, antioxidant and antimicrobial activities of PSA were studied by different in vitro assays. Results indicated that the optimal extraction conditions were as follows: the ratio of water to raw of 30 mL/g, extraction time of 46.50 min, ultrasonic temperature of 72.00 °C, and ultrasonic power of 230 W. Under these conditions, the obtained PSA yield (13.21 ± 0.37%) was closely agreed with the predicted yield by the model. The average molecular weights of the PSA were estimated to be 5.34 × 10³ and 6.27 × 10⁵ Da. Monosaccharide composition analysis indicated that PSA consisted of mannose, galactose uronic acid, glucose, galactose, arabinose with a molar ratio of 1.83:0.55:75.75:1.94:0.45. Furthermore, PSA exhibited moderate antioxidant and antibacterial activities in vitro. Collectively, this study provides a promising strategy to obtain bioactive polysaccharides from processed products of herbal medicines.

  17. Optimization of ultrasound-assisted extraction of phenolic compounds, antioxidants, and anthocyanins from grape (Vitis vinifera) seeds.

    Science.gov (United States)

    Ghafoor, Kashif; Choi, Yong Hee; Jeon, Ju Yeong; Jo, In Hee

    2009-06-10

    Important functional components from Campbell Early grape seed were extracted by ultrasound-assisted extraction (UAE) technology. The experiments were carried out according to a five level, three variable central composite rotatable design (CCRD). The best possible combinations of ethanol concentration, extraction temperature, and extraction time with the application of ultrasound were obtained for the maximum extraction of phenolic compounds, antioxidant activities, and anthocyanins from grape seed by using response surface methodology (RSM). Process variables had significant effect on the extraction of functional components with extraction time being highly significant for the extraction of phenolics and antioxidants. The optimal conditions obtained by RSM for UAE from grape seed include 53.15% ethanol, 56.03 degrees C temperature, and 29.03 min time for the maximum total phenolic compounds (5.44 mg GAE/100 mL); 53.06% ethanol, 60.65 degrees C temperature, and 30.58 min time for the maximum antioxidant activity (12.31 mg/mL); and 52.35% ethanol, 55.13 degrees C temperature, and 29.49 min time for the maximum total anthocyanins (2.28 mg/mL). Under the above-mentioned conditions, the experimental total phenolics were 5.41 mg GAE/100 mL, antioxidant activity was 12.28 mg/mL, and total anthocyanins were 2.29 mg/mL of the grape seed extract, which is well matched with the predicted values.

  18. Optimization for ultrasound-assisted extraction of polysaccharides with chemical composition and antioxidant activity from the Artemisia sphaerocephala Krasch seeds.

    Science.gov (United States)

    Zheng, Quan; Ren, Daoyuan; Yang, Nana; Yang, Xingbin

    2016-10-01

    Artemisia sphaerocephala Krasch seeds polysaccharides have been reported to have a variety of important biological activities. However, effective extraction of Artemisia sphaerocephala Krasch seeds polysaccharides is still an unsolved issue. In this study, the orthogonal rotatable central composite design was employed to optimize ultrasound-assisted extraction conditions of Artemisia sphaerocephala Krasch seeds polysaccharides. Based on a single-factor analysis method, ultrasonic power, extraction time, solid-liquid ratio and extraction temperature were shown to significantly affect the yield of polysaccharides extracted from the A. sphaerocephala Krasch seeds. The optimal conditions for extraction of Artemisia sphaerocephala Krasch seeds polysaccharides were determined as following: ultrasonic power 243W, extraction time 125min, solid-liquid ratio 64:1 and extraction temperature 64°C, where the experimental yield was 14.78%, which was well matched with the predicted value of 14.81%. Furthermore, ASKP was identified as a typical heteropolysaccharide with d-galacturonic acid (38.8%) d-galactose (20.2%) and d-xylose (15.5%) being the main constitutive monosaccharides. Moreover, Artemisia sphaerocephala Krasch seeds polysaccharides exhibited high total reducing power and considerable scavenging activities on DPPH, hydroxyl and superoxide radicals, in a concentration-dependent manner in vitro. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Optimization of Ultrasound-Assisted Extraction of Natural Antioxidants from Sugar Apple (Annona squamosa L.) Peel Using Response Surface Methodology.

    Science.gov (United States)

    Deng, Gui-Fang; Xu, Dong-Ping; Li, Sha; Li, Hua-Bin

    2015-11-17

    Sugar apple (Annona squamosa L.) is a popular tropical fruit and its peel is a municipal waste. An ultrasound-assisted extraction method was developed for the recovery of natural antioxidants from sugar apple peel. Central composite design was used to optimize solvent concentration (13.2%-46.8%), ultrasonic time (33.2-66.8 min), and temperature (43.2-76.8 °C) for the recovery of natural antioxidants from sugar apple peel. The second-order polynomial models demonstrated a good fit of the quadratic models with the experimental results in respect to total phenolic content (TPC, R²=0.9524, pextraction conditions were 20:1 (mL/g) of solvent-to-solid ratio, 32.68% acetone, and 67.23 °C for 42.54 min under ultrasonic irradiation. Under these conditions, the maximal yield of total phenolic content was 26.81 (mg GA/g FW). The experimental results obtained under optimal conditions agreed well with the predicted results. The application of ultrasound markedly decreased extraction time and improved the extraction efficiency, compared with the conventional methods.

  20. Synthesis and application of magnetic deep eutectic solvents: Novel solvents for ultrasound assisted liquid-liquid microextraction of thiophene.

    Science.gov (United States)

    Khezeli, Tahere; Daneshfar, Ali

    2017-09-01

    Two novel magnetic deep eutectic solvents (MDESs), comprised of cheap and simple components named [choline chloride/phenol] [FeCl 4 ] and [choline chloride/ethylene glycol] [FeCl 4 ] were prepared and characterized by CHN elemental analysis, proton nuclear magnetic resonance ( 1 H NMR), vibrating sample magnetometery (VSM), Raman, Fourier transform-infrared (FT-IR) and UV-Vis spectrometery. The extraction efficiency of the prepared MDESs has been investigated in ultrasound assisted liquid-liquid microextraction based MDES (UALLME-MDES). Briefly, MDESs were added to n-heptan containing thiophene. Then, MDESs were dispersed in n-heptane by sonication. After that, microdroplets of MDESs were collected by a magnet and the remained concentration of thiophene in n-heptane phase was analyzed by GC-FID. The results indicated that [choline chloride/phenol] [FeCl 4 ] has higher extraction efficiency than [choline chloride/ethylene glycol] [FeCl 4 ]. This work opens a new way to the application of MDESs. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Continuous-flow ultrasound assisted oxidative desulfurization (UAOD) process: An efficient diesel treatment by injection of the aqueous phase.

    Science.gov (United States)

    Rahimi, Masoud; Shahhosseini, Shahrokh; Movahedirad, Salman

    2017-11-01

    A new continuous-flow ultrasound assisted oxidative desulfurization (UAOD) process was developed in order to decrease energy and aqueous phase consumption. In this process the aqueous phase is injected below the horn tip leading to enhanced mixing of the phases. Diesel fuel as the oil phase with sulfur content of 1550ppmw and an appropriate mixture of hydrogen peroxide and formic acid as the aqueous phase were used. At the first step, the optimized condition for the sulfur removal has been obtained in the batch mode operation. Hence, the effect of more important oxidation parameters; oxidant-to-sulfur molar ratio, acid-to-sulfur molar ratio and sonication time were investigated. Then the optimized conditions were obtained using Response Surface Methodology (RSM) technique. Afterwards, some experiments corresponding to the best batch condition and also with objective of minimizing the residence time and aqueous phase to fuel volume ratio have been conducted in a newly designed double-compartment reactor with injection of the aqueous phase to evaluate the process in a continuous flow operation. In addition, the effect of nozzle diameter has been examined. Significant improvement on the sulfur removal was observed specially in lower sonication time in the case of dispersion method in comparison with the conventional contact between two phases. Ultimately, the flow pattern induced by ultrasonic device, and also injection of the aqueous phase were analyzed quantitatively and qualitatively by capturing the sequential images. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Intensification of extraction of curcumin from Curcuma amada using ultrasound assisted approach: Effect of different operating parameters.

    Science.gov (United States)

    Shirsath, S R; Sable, S S; Gaikwad, S G; Sonawane, S H; Saini, D R; Gogate, P R

    2017-09-01

    Curcumin, a dietary phytochemical, has been extracted from rhizomes of Curcuma amada using ultrasound assisted extraction (UAE) and the results compared with the conventional extraction approach to establish the process intensification benefits. The effect of operating parameters such as type of solvent, extraction time, extraction temperature, solid to solvent ratio, particle size and ultrasonic power on the extraction yield have been investigated in details for the approach UAE. The maximum extraction yield as 72% was obtained in 1h under optimized conditions of 35°C temperature, solid to solvent ratio of 1:25, particle size of 0.09mm, ultrasonic power of 250W and ultrasound frequency of 22kHz with ethanol as the solvent. The obtained yield was significantly higher as compared to the batch extraction where only about 62% yield was achieved in 8h of treatment. Peleg's model was used to describe the kinetics of UAE and the model showed a good agreement with the experimental results. Overall, ultrasound has been established to be a green process for extraction of curcumin with benefits of reduction in time as compared to batch extraction and the operating temperature as compared to Soxhlet extraction. Copyright © 2017. Published by Elsevier B.V.

  3. Optimization of ultrasound-assisted extraction of phenolic compounds, antioxidants and rosmarinic acid from perilla leaves using response surface methodology

    Directory of Open Access Journals (Sweden)

    Hui-Zhen LI

    Full Text Available Abstract Response surface methodology (RSM was used to optimize ultrasound-assisted extraction (UAE of functional components from perilla leaves. The factors investigated were ethanol concentration, extraction temperature, and extraction time. The results revealed that ethanol concentration had significant effects on all extraction parameters. Based on the RSM results, the optimal conditions were an ethanol concentration of 56%, a UAE temperature of 54 °C, and a UAE time of 55 min. Under these conditions, the experimental TPC (total phenolic content, RA (rosmarinic acid, FRAP (ferric reducing antioxidant power and DPPH (1,1-diphenyl-2-picrylhydrazyl values were 48.85 mg GAE/g DW (mg gallic acid equivalent /g of dry weight, 31.02 mg/g DW, 85.55 μmol Fe2+/g DW and 73.35%, respectively. The experimental values were in agreement with those predicted by RSM models, confirming suitability of the model employed and the success of RSM for optimization of the extraction conditions.

  4. Optimization of ultrasound-assisted extraction of colchicine compound from Colchicum haussknechtii by using response surface methodology

    Directory of Open Access Journals (Sweden)

    Saeid Khodadoust

    2017-04-01

    Full Text Available In this research an ultrasound-assisted extraction (UAE method was used for extraction of colchicine in root of Colchicum haussknechtii prior to high-performance liquid chromatography with UV detection. C. haussknechtii is used widely in traditional medicine for the treatment of various diseases. The root of this plant is full of colchicine that is suitable for the treatment of gout and cirrhosis and applicable in plant breeding studies to produce polyploidy. The influence of variables on the extraction method was investigated by response surface methodology (RSM and composite design (CCD to achieve maximum extraction yield of colchicine from the root of C. haussknechtii. The most suitable condition for the extraction of colchicine was found to at 40 °C temperature, 32 min extraction time, and 70:30 v/v ethanol–water mixtures with 45:1 solvent-solid ratio. Obtained results showed that there is 1.2% colchicine in the root of C. haussknechtii, so this plant could be introduced as a rich source of colchicine.

  5. Optimization of Ultrasound-Assisted Extraction of Natural Antioxidants from Sugar Apple (Annona squamosa L. Peel Using Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Gui-Fang Deng

    2015-11-01

    Full Text Available Sugar apple (Annona squamosa L. is a popular tropical fruit and its peel is a municipal waste. An ultrasound-assisted extraction method was developed for the recovery of natural antioxidants from sugar apple peel. Central composite design was used to optimize solvent concentration (13.2%–46.8%, ultrasonic time (33.2–66.8 min, and temperature (43.2–76.8 °C for the recovery of natural antioxidants from sugar apple peel. The second-order polynomial models demonstrated a good fit of the quadratic models with the experimental results in respect to total phenolic content (TPC, R2 = 0.9524, p < 0.0001, FRAP (R2 = 0.9743, p < 0.0001, and TEAC (R2 = 0.9610, p < 0.0001 values. The optimal extraction conditions were 20:1 (mL/g of solvent-to-solid ratio, 32.68% acetone, and 67.23 °C for 42.54 min under ultrasonic irradiation. Under these conditions, the maximal yield of total phenolic content was 26.81 (mg GA/g FW. The experimental results obtained under optimal conditions agreed well with the predicted results. The application of ultrasound markedly decreased extraction time and improved the extraction efficiency, compared with the conventional methods.

  6. Ultrasound-assisted extraction and preliminary purification of proanthocyanidins and chlorogenic acid from almond (Prunus dulcis) skin.

    Science.gov (United States)

    Ma, Xue; Zhou, Xin-Yu; Qiang, Qian-Qian; Zhang, Zhi-Qi

    2014-07-01

    An aqueous solution of polyethylene glycol (PEG) as a green solvent was employed for the first time to develop the ultrasound-assisted extraction of proanthocyanidins (PA) and chlorogenic acid (CA) from almond skin. The optimized extraction parameters were determined based on response surface methodology, and corresponded to an ultrasound power of 120 W, a liquid-to-solid ratio of 20:1 (mL/g), and a PEG concentration of 50% (v/v). Under these optimized conditions, the extraction yields of PAs and CA from almond skin were 32.68 ± 0.22 and 16.01 ± 0.19 mg/g, respectively. Compared with organic solvent extraction, PEG solution extraction produced higher yields. Different macroporous resins were compared for their performance in purifying PAs and CA from almond skin extract. Static adsorption/desorption experimental results demonstrated that AB-8 resin exhibits excellent purification performance at pH 4. Under the optimized dynamic adsorption/desorption conditions on the AB-8 column, the total recovery of purification for PAs and CA was 80.67%. The total content of PAs and CA in the preliminarily purified extract was 89.17% (with respective contents of 60.90 and 28.27%). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Ultrasound-assisted xanthation of cellulose from lignocellulosic biomass optimized by response surface methodology for Pb(II) sorption.

    Science.gov (United States)

    Wang, Chongqing; Wang, Hui; Gu, Guohua

    2018-02-15

    Alkali treatment of lignocellulosic biomass is conducted to remove hemi-cellulose and lignin, further increasing the reactivity and accessibility of cellulose. Ultrasound-assisted xanthation of alkali cellulose is optimized by response surface methodology (RSM) with a Box-Behnken design. A predicting mathematical model is obtained by fitting experimental data, and it is verified by analysis of variance. Response surface plots and the contour plots obtained from the model are applied to determine the interactions of experimental variables. The optimum conditions are NaOH concentration 1.3mol/L, ultrasonic time 71.6min and CS 2 dosage 1.5mL. FTIR, SEM and XPS characterizations confirm the synthesis and sorption mechanism of cellulose xanthate (CX). Biosorption of Pb (II) onto CX obeys pseudo-second order model and Langmuir model. The sorption mechanism is attributed to surface complexation or ion exchange. CX shows good reusability for Pb (II) sorption. The maximum sorption capacity of Pb(II) is 134.41mg/g, higher than that of other biosorbents. CX has great potential as an efficient and low-cost biosorbent for wastewater treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Determination of Oleanolic and Ursolic Acids in Hedyotis diffusa Using Hyphenated Ultrasound-Assisted Supercritical Carbon Dioxide Extraction and Chromatography

    Science.gov (United States)

    Hong, Show-Jen

    2015-01-01

    Oleanolic acid (OA) and ursolic acid (UA) were extracted from Hedyotis diffusa using a hyphenated procedure of ultrasound-assisted and supercritical carbon dioxide (HSC–CO2) extraction at different temperatures, pressures, cosolvent percentages, and SC–CO2 flow rates. The results indicated that these parameters significantly affected the extraction yield. The maximal yields of OA (0.917 mg/g of dry plant) and UA (3.540 mg/g of dry plant) were obtained at a dynamic extraction time of 110 min, a static extraction time of 15 min, 28.2 MPa, and 56°C with a 12.5% (v/v) cosolvent (ethanol/water = 82/18, v/v) and SC–CO2 flowing at 2.3 mL/min (STP). The extracted yields were then analyzed by high performance liquid chromatography (HPLC) to quantify the OA and UA. The present findings revealed that H. diffusa is a potential source of OA and UA. In addition, using the hyphenated procedure for extraction is a promising and alternative process for recovering OA and UA from H. diffusa at high concentrations. PMID:26089939

  9. Comparison of Ultrasound-Assisted and Regular Leaching of Vanadium and Chromium from Roasted High Chromium Vanadium Slag

    Science.gov (United States)

    Wen, Jing; Jiang, Tao; Gao, Huiyang; Liu, Yajing; Zheng, Xiaole; Xue, Xiangxin

    2018-02-01

    Ultrasound-assisted leaching (UAL) was used for vanadium and chromium leaching from roasted material obtained by the calcification roasting of high-chromium-vanadium slag. UAL was compared with regular leaching. The effect of the leaching time and temperature, acid concentration, and liquid-solid ratio on the vanadium and chromium leaching behaviors was investigated. The UAL mechanism was determined from particle-size-distribution and microstructure analyses. UAL decreased the reaction time and leaching temperature significantly. Furthermore, 96.67% vanadium and less than 1% chromium were leached at 60°C for 60 min with 20% H2SO4 at a liquid-solid ratio of 8, which was higher than the maximum vanadium leaching rate of 90.89% obtained using regular leaching at 80°C for 120 min. Ultrasonic waves broke and dispersed the solid sample because of ultrasonic cavitation, which increased the contact area of the roasted sample and the leaching medium, the solid-liquid mass transfer, and the vanadium leaching rate.

  10. Ultrasound-Assisted Thoracic Paravertebral Block Reduces Intraoperative Opioid Requirement and Improves Analgesia after Breast Cancer Surgery: A Randomized, Controlled, Single-Center Trial.

    Directory of Open Access Journals (Sweden)

    Lijian Pei

    Full Text Available The contribution of ultrasound-assisted thoracic paravertebral block to postoperative analgesia remains unclear. We compared the effect of a combination of ultrasound assisted-thoracic paravertebral block and propofol general anesthesia with opioid and sevoflurane general anesthesia on volatile anesthetic, propofol and opioid consumption, and postoperative pain in patients having breast cancer surgery.Patients undergoing breast cancer surgery were randomly assigned to ultrasound-assisted paravertebral block with propofol general anesthesia (PPA group, n = 121 or fentanyl with sevoflurane general anesthesia (GA group, n = 126. Volatile anesthetic, propofol and opioid consumption, and postoperative pain intensity were compared between the groups using noninferiority and superiority tests.Patients in the PPA group required less sevoflurane than those in the GA group (median [interquartile range] of 0 [0, 0] vs. 0.4 [0.3, 0.6] minimum alveolar concentration [MAC]-hours, less intraoperative fentanyl requirements (100 [50, 100] vs. 250 [200, 300]μg,, less intense postoperative pain (median visual analog scale score 2 [1, 3.5] vs. 3 [2, 4.5], but more propofol (median 529 [424, 672] vs. 100 [100, 130] mg. Noninferiority was detected for all four outcomes; one-tailed superiority tests for each outcome were highly significant at P<0.001 in the expected directions.The combination of propofol anesthesia with ultrasound-assisted paravertebral block reduces intraoperative volatile anesthetic and opioid requirements, and results in less post operative pain in patients undergoing breast cancer surgery.ClinicalTrial.gov NCT00418457.

  11. Optimization of ultrasound-assisted extraction of pectinase enzyme from guava (Psidium guajava) peel: Enzyme recovery, specific activity, temperature, and storage stability.

    Science.gov (United States)

    Amid, Mehrnoush; Murshid, Fara Syazana; Manap, Mohd Yazid; Islam Sarker, Zaidul

    2016-01-01

    This study aimed to investigate the effects of the ultrasound-assisted extraction conditions on the yield, specific activity, temperature, and storage stability of the pectinase enzyme from guava peel. The ultrasound variables studied were sonication time (10-30 min), ultrasound temperature (30-50 °C), pH (2.0-8.0), and solvent-to-sample ratio (2:1 mL/g to 6:1 mL/g). The main goal was to optimize the ultrasound-assisted extraction conditions to maximize the recovery of pectinase from guava peel with the most desirable enzyme-specific activity and stability. Under the optimum conditions, a high yield (96.2%), good specific activity (18.2 U/mg), temperature stability (88.3%), and storage stability (90.3%) of the extracted enzyme were achieved. The optimal conditions were 20 min sonication time, 40 °C temperature, at pH 5.0, using a 4:1 mL/g solvent-to-sample ratio. The study demonstrated that optimization of ultrasound-assisted process conditions for the enzyme extraction could improve the enzymatic characteristics and yield of the enzyme.

  12. Nanoparticles in ionic liquids: interactions and organization.

    Science.gov (United States)

    He, Zhiqi; Alexandridis, Paschalis

    2015-07-28

    Ionic liquids (ILs), defined as low-melting organic salts, are a novel class of compounds with unique properties and a combinatorially great chemical diversity. Ionic liquids are utilized as synthesis and dispersion media for nanoparticles as well as for surface functionalization. Ionic liquid and nanoparticle hybrid systems are governed by a combined effect of several intermolecular interactions between their constituents. For each interaction, including van der Waals, electrostatic, structural, solvophobic, steric, and hydrogen bonding, the characterization and quantitative calculation methods together with factors affecting these interactions are reviewed here. Various self-organized structures based on nanoparticles in ionic liquids are generated as a result of a balance of these intermolecular interactions. These structures, including colloidal glasses and gels, lyotropic liquid crystals, nanoparticle-stabilized ionic liquid-containing emulsions, ionic liquid surface-functionalized nanoparticles, and nanoscale ionic materials, possess properties of both ionic liquids and nanoparticles, which render them useful as novel materials especially in electrochemical and catalysis applications. This review of the interactions within nanoparticle dispersions in ionic liquids and of the structure of nanoparticle and ionic liquid hybrids provides guidance on the rational design of novel ionic liquid-based materials, enabling applications in broad areas.

  13. Potentiostat for Characterizing Microstructures at Ionic Liquid/Electrode Interfaces

    Science.gov (United States)

    2015-10-10

    reviewed journals (N/A for none) C. Zibart, D. Parr, B. Egan, H. Morris, A. Tivanski, L. M. Haverhals, “Investigation of Structure at Gold- Ionic Liquid ...into our electrochemistry program. In short, the instrument has been of great service to characterize ionic liquid -based (IL-based) electrolyte...Aug-2014 14-Nov-2014 Approved for Public Release; Distribution Unlimited Final Report: Potentiostat for Characterizing Microstructures at Ionic Liquid

  14. Simultaneous in situ derivatization and ultrasound-assisted dispersive magnetic solid phase extraction for thiamine determination by spectrofluorimetry.

    Science.gov (United States)

    Tarigh, Ghazale Daneshvar; Shemirani, Farzaneh

    2014-06-01

    A simple and rapid method for the simultaneous in situ derivatizaion, preconcentration and extraction of thiamine (vitamin B1) as a model analyte was developed by a novel quantitative method, namely ultrasound-assisted dispersive magnetic solid phase extraction spectrofluorimetry (USA-DMSPE-FL) from different real samples. This method consists of sample preparation, in situ derivatization, exhaustive extraction and clean up by a single process. High extraction efficiency and in situ derivatization in a short period of time is the main advantages of this procedure. For this purpose, the reusable magnetic multi-wall carbon nanotube (MMWCNT) nanocomposite was used as an adsorbent for preconcentration and determination of thiamine. Thiamine was, simultaneously, in situ derivatized as thiochrome by potassium hexacyanoferrate (III) and adsorbed on MMWCNT in an ultrasonic water bath. The MMWCNTs were then collected using an external magnetic field. Subsequently, the extracted thiochrome was washed from the surface of the adsorbent and determined by spectrofluorimetry. The developed method, which has been analytically characterized under its optimal operating conditions, allows the detection of the analyte in the samples with method detection limits of 0.37 µg L(-1). The repeatability of the method, expressed as the relative standard deviation (RSD, n=6), varies between 2.0% and 4.8% in different real samples, while the enhancement factor is 197. The proposed procedure has been applied for the determination of thiamine in biological (serum and urine), pharmaceutical (multivitamin tablet and B complex syrup) and foodstuff samples (cereal, wheat flour, banana and honey) with the good recoveries in the range from 90% to 105%. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Employing Response Surface Methodology for the Optimization of Ultrasound Assisted Extraction of Lutein and β-Carotene from Spinach

    Directory of Open Access Journals (Sweden)

    Ammar Altemimi

    2015-04-01

    Full Text Available The extraction of lutein and β-carotene from spinach (Spinacia oleracea L. leaves is important to the dietary supplement industry. A Box-Behnken design and response surface methodology (RSM were used to investigate the effect of process variables on the ultrasound-assisted extraction (UAE of lutein and β-carotene from spinach. Three independent variables, extraction temperature (°C, extraction power (% and extraction time (min were studied. Thin-layer chromatography (TLC followed by UV visualization and densitometry was used as a simple and rapid method for both identification and quantification of lutein and β-carotene during UAE. Methanol extracts of leaves from spinach and authentic standards of lutein and β-carotene were separated by normal-phase TLC with ethyl acetate-acetone (5:4 (v/v as the mobile phase. In this study, the combination of TLC, densitometry, and Box–Behnken with RSM methods were effective for the quantitative analysis of lutein and β-carotene from spinach extracts. The resulting quadratic polynomial models for optimizing lutein and β-carotene from spinach had high coefficients of determination of 0.96 and 0.94, respectively. The optimal UAE settings for output of lutein and β-carotene simultaneously from spinach extracts were an extraction temperature of 40 °C, extraction power of 40% (28 W/cm3 and extraction time of 16 min. The identity and purity of each TLC spot was measured using time-of-flight mass spectrometry. Therefore, UAE assisted extraction of carotenes from spinach can provide a source of lutein and β-carotene for the dietary supplement industry.

  16. Instant controlled pressure drop technology and ultrasound assisted extraction for sequential extraction of essential oil and antioxidants.

    Science.gov (United States)

    Allaf, Tamara; Tomao, Valérie; Ruiz, Karine; Chemat, Farid

    2013-01-01

    The instant controlled pressure drop (DIC) technology enabled both the extraction of essential oil and the expansion of the matrix itself which improved solvent extraction. The sequential use of DIC and Ultrasound Assisted Extraction (UAE) triggered complementary actions materialized by supplementary effects. We visualized these combination impacts by comparing them to standard techniques: Hydrodistillation (HD) and Solvent Extraction (SE). First, the extraction of orange peel Essential Oils (EO) was achieved by HD during 4h and DIC process (after optimization) during 2 min; EO yields was 1.97 mg/g dry material (dm) with HD compared to 16.57 mg/g d m with DIC. Second, the solid residue was recovered to extract antioxidant compounds (naringin and hesperidin) by SE and UAE. Scanning electron microscope showed that after HD the recovered solid shriveled as opposite to DIC treatment which expanded the product structure. HPLC analyses showed that the best kinetics and yields of naringin and hesperidin extraction was when DIC and UAE are combined. Indeed, after 1h of extraction, DIC treated orange peels with UAE were 0.825 ± 1.6 × 10(-2)g/g of dry material (dm) for hesperidin and 6.45 × 10(-2) ± 2.3 × 10(-4)g/g d m for naringin compared to 0.64 ± 2.7 × 10(-2)g/g of dry material (dm) and 5.7 × 10(-2) ± 1.6 × 10(-3)g/g d m, respectively with SE. By combining DIC to UAE, it was possible to enhance kinetics and yields of antioxidant extraction. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. Ultrasound-assisted extraction of arabinogalactan and dihydroquercetin simultaneously from Larix gmelinii as a pretreatment for pulping and papermaking.

    Directory of Open Access Journals (Sweden)

    Chunhui Ma

    Full Text Available An ultrasound-assisted extraction (UAE method using ethanol was applied for extracting arabinogalactan (AG and dihydroquercetin (DHQ simultaneously from larch wood, as a pretreatment for pulping and papermaking. The extraction parameters were optimized by a Box-Behnken experimental design with the yields of AG and DHQ as the response values. Under optimum conditions (three extractions, each using 40% ethanol, for 50 min, 200 W ultrasound power and 1∶18 solid-liquid ratio, the yields of AG and DHQ were 183.4 and 36.76 mg/g, respectively. After UAE pretreated, the wood chips were used for Kraft pulping (KP and high boiling solvent pulping (HBSP. The pulping yield after pretreatment was higher than that of untreated (the pulping yields of untreated HBSP and KP were 42.37% and 39.60%, and the pulping yields of HBSP and KP after UAE-pretreated were 44.23% and 41.50% respectively, as indicated by a lower kappa number (77.91 and 27.30 for untreated HBSP and KP; 77.01 and 26.83 for UAE-pretreated HBSP and KP. Furthermore, the characteristics of paper produced from pretreated wood chips were superior to those from the untreated chips: the basis weight was lower (85.67 and 82.48 g·cm(-2 for paper from untreated KP and HBSP; 79.94 and 80.25 g·cm(-2 for paper from UAE-pretreated KP and HBSP, and the tensile strengths, tearing strengths, bursting strengths, and folding strengths were higher than these of paper after UAE-pretreated, respectively.

  18. Optimized Ultrasound-Assisted Oxidative Desulfurization Process of Simulated Fuels over Activated Carbon-Supported Phosphotungstic Acid

    Directory of Open Access Journals (Sweden)

    Peniel Jean Gildo

    2018-01-01

    Full Text Available Recent technological advancements respond to the call to minimize/eliminate emissions to the atmosphere. However, on the average, fuel oils which is one of the major raw materials, is found to increase in sulfur concentration due to a phenomenon called thermal maturation. As such, a deeper desulfurization process is needed to obtain low/ultra-low sulfur fuel oils. In the present study, the ultrasound assisted oxidative desulfurization (UAOD processes using the H2O2 and HPW-AC oxidizing system applied to simulated fuel (~2800 ppm sulfur in the form of dibenzothiophene, benzothiophene, and thiophene dissolved in toluene, were optimized. After the pre-saturation of the HPW-AC with the simulated fuel, H2O2 was added just before the reaction was commenced under ultrasonic irradiation. After the application of both 2k-factorial design of experiment for screening and Face-Centered Design of Experiment for optimization, it was found that 25.52 wt% of H2O2 concentration, 983.9 mg of catalyst dose, 9.52 mL aqueous phase per 10 mL of the organic phase and 76.36 minutes of ultrasonication time would render 94.74% oxidation of the sulfur compounds in the simulated fuel. After the application of the optimized parameters to kerosene and employing a 4-cycle extraction using acetonitrile, 99% of the original sulfur content were removed from the kerosene using the UAOD optimized parameters. The desulfurization process resulted in a low-sulfur kerosene which retained its basic fuel properties such as density, viscosity and calorific value.

  19. Production of graphene quantum dots by ultrasound-assisted exfoliation in supercritical CO2/H2O medium.

    Science.gov (United States)

    Gao, Hanyang; Xue, Chen; Hu, Guoxin; Zhu, Kunxu

    2017-07-01

    In this research, three kinds of graphene quantum dots (GQDs)-pristine graphene quantum dots (PGQDs), expanded graphene quantum dots (EGQDs) and graphene oxide quantum dots (GOQDs)-were produced from natural graphite, expanded graphite, and oxide graphite respectively in an ultrasound-assisted supercritical CO 2 (scCO 2 )/H 2 O system. The effects of aqueous solution content ratio, system pressure, and ultrasonic power on the yields of different kinds of GQDs were investigated. According to these experiment results, the combination of the intense knocking force generated from high-pressure acoustic cavitation in a scCO 2 /H 2 O system and the superior penetration ability of scCO 2 was considered to be the key to the successful exfoliation of such tiny pieces from bulk graphite. An interesting result was found that, contrary to common experience, the yield of PGQDs from natural graphite was much higher than that of GOQDs from graphite oxide. Based on the experimental analysis, the larger interlayer resistance of natural graphite, which hindered the insertion of scCO 2 molecules, and the hydrophobic property of natural graphite surface, which made the planar more susceptible to the attack of ultrasonic collapsing bubbles, were deduced to be the two main reasons for this result. The differences in characteristics among the three kinds of GQDs were also studied and compared in this research. In our opinion, this low-cost and time-saving method may provide an alternative green route for the production of various kinds of GQDs, especially PGQDs. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Direct ultrasound-assisted extraction and characterization of phenolic compounds from fresh houseleek (Sempervivum marmoreum L. leaves

    Directory of Open Access Journals (Sweden)

    Karabegović Ivana T.

    2018-01-01

    Full Text Available The effects of ultrasound power and frequency on the yield of total extractive substances (TES, total phenolic content (TPC, total flavonoid content (TFC and antioxidant activity (AOA of fresh houseleek leaves extracts obtained by direct ultrasound-assisted extraction (DUAE were studied. Preliminary extraction of plant material was performed using methanol, acetone and 2-propanol by Soxhlet extraction. It was found that maximum TES yield could be obtained by methanol extraction (2.91±0.02, followed by acetone and 2-propanol with a TES yield of 2.32±0.01 and 2.01±0.03 g per 100 g of fresh plant material, respectively. In the fresh houseleek leaves extracts obtained by DUAE and methanol as the chosen solvent, TPC, TFC and AOA were in the ranges of: 40.5–85.9 mg gallic acid/g dry extract, 12.7–19.3 mg rutin/g dry extract and 24.6–108.2μg/ml, respectively. The results showed that the increase in the ultrasound power and extraction time have positive and significant (p < 0.05 effects on the TPC, TFC and AOA, while the increase in the ultrasound frequency leads to a decrease in the TPC, TFC and AOA of the extracts. A chromatographic analysis of crude extract identified the following: kaempferol 3-O-(6’’-O-malonylglucoside- 7-O-glucosyde, kaempferol 3-O-glucoside-7-O-rhamnoside, luteolin 5-O-(6’’-O-malonylglucoside, kaempferol 3-O-(6’’-O-acetylglucoside-7-O-rhamnoside, genkwanin 5-O-glucoside, luteolin 5-O-(6’’-O-malonylglucoside, kaempferol 3-O-(6’’-O-malonylglucoside, kaempferol 3-O-rhamnoside, quercetin, genkwanin 4’-O-glucoside and hyperoside. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 172047

  1. Ultrasound assisted enzymatic hydrolysis for isolating titanium dioxide nanoparticles from bivalve mollusk before sp-ICP-MS.

    Science.gov (United States)

    Taboada-López, María Vanesa; Iglesias-López, Sara; Herbello-Hermelo, Paloma; Bermejo-Barrera, Pilar; Moreda-Piñeiro, Antonio

    2018-08-14

    Applicability of single-particle inductively coupled plasma mass spectrometry (sp-ICP-MS) using dwell times equal to or shorter than 100 μs has been tested for assessing titanium dioxide nanoparticles (TiO 2 NPs) in bivalve mollusks. TiO 2 NPs isolation from fresh mollusk tissues was achieved by ultrasound assisted enzymatic hydrolysis procedure using a pancreatin/lipase mixture. Optimum extraction conditions imply ultrasonication (60% amplitude) for 10 min, and 7.5 mL of a solution containing 3.0 g L -1 of pancreatin and lipase (pH 7.4). The developed method was found to be repeatable (repeatability of 17% for the over-all procedure, TiO 2 NPs concentration of 5.33 × 10 7  ± 8.89 × 10 6 , n = 11), showing a limit of detection of 5.28 × 10 6 NPs g -1 , and a limit of detection in size of 24.4-30.4 nm, based on the 3σ criteria, and on the 3σ/5 σ criteria, respectively. The analytical recovery within the 90-99% range (use of TiO 2 NPs standards of 50 nm at 7 and 14 μg L -1 as Ti). Several bivalve mollusks (clams, cockles, mussels, razor clams, oysters and variegated scallops) were analyzed for total titanium (ICP-MS after microwave assisted acid digestion), and for TiO 2 NPs by the proposed method. TiO 2 NPs concentrations were within the 2.36 × 10 7 -1.25 × 10 8 NPs g -1 range, and the most frequent sizes were from 50 to 70 nm. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Ultrasound assisted green synthesis of cerium oxide nanoparticles using Prosopis juliflora leaf extract and their structural, optical and antibacterial properties

    Directory of Open Access Journals (Sweden)

    Arunachalam Thirunavukkarasu

    2018-03-01

    Full Text Available Cerium oxide nanoparticles (CONPs were prepared using ultrasound assisted leaf extract of Prosopis juliflora acting as a reducing as well as stabilizing agent. The synthesized CONPs were characterized by ultraviolet-visible absorption spectroscopy (UV-Vis, particle size analyzer (PSA, Fourier transform infrared spectroscopy (FT-IR, Raman spectroscopy, X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS and high-resolution transmission electron microscopy (HRTEM. From the UV-Vis analysis, the optical band gap of the prepared CONPs (Eg = 3.62 eV was slightly increased as compared to the bulk ceria (Eg = 3.19 eV. The phytochemicals in the extract reduced the particle size to 3.7 nm ± 0.3 nm, as it is evident from the PSA. FT-IR results confirmed the Ce-O stretching bands by showing the peaks at 452 cm-1. The Raman spectrumshowed a characteristic peak shift for CONPs at 461.2 cm-1. XRD analysis revealed the cubic fluorite structure of the synthesizednanoparticles with the lattice constant, a of 5.415 Å and unit cell volume, V of 158.813 Å3. XPS signals were used to determine the concentration of Ce3+ and Ce4+ in the prepared CONPs and it was found that major amount of cerium exist in the Ce4+ state. HRTEM images showed spherical shaped particles with an average size of 15 nm. Furthermore, the antibacterial activity of the prepared CONPs was evaluated and their efficacies were compared with the conventional antibiotics using disc diffusion assay against a set of Gram positive (G+ bacteria (Staphylococcus aureus, Streptococcus pneumonia and Gram negative (G- bacteria (Pseudomonas aeruginosa, Proteus vulgaris. The results suggested that CONPs showed antibacterial activity with significant variations due to the differences in the membrane structure and cell wall composition among the two groups tested.

  3. Spatial and temporal profile of cisplatin delivery by ultrasound-assisted intravesical chemotherapy in a bladder cancer model.

    Directory of Open Access Journals (Sweden)

    Noboru Sasaki

    Full Text Available Non-muscle invasive bladder cancer is one of the most common tumors of the urinary tract. Despite the current multimodal therapy, recurrence and progression of disease have been challenging problems. We hereby introduced a new approach, ultrasound-assisted intravesical chemotherapy, intravesical instillation of chemotherapeutic agents and microbubbles followed by ultrasound exposure. We investigated the feasibility of the treatment for non-muscle invasive bladder cancer. In order to evaluate intracellular delivery and cytotoxic effect as a function to the thickness, we performed all experiments using a bladder cancer mimicking 3D culture model. Ultrasound-triggered microbubble cavitation increased both the intracellular platinum concentration and the cytotoxic effect of cisplatin at the thickness of 70 and 122 μm of the culture model. The duration of enhanced cytotoxic effect of cisplatin by ultrasound-triggered microbubble cavitation was approximately 1 hr. Based on the distance and duration of delivery, we further tested the feasibility of repetition of the treatment. Triple treatment increased the effective distance by 1.6-fold. Our results clearly showed spatial and temporal profile of delivery by ultrasound-triggered microbubble cavitation in a tumor-mimicking structure. Furthermore, we demonstrated that the increase in intracellular concentration results in the enhancement of the cytotoxic effect in a structure with the certain thickness. Repetition of ultrasound exposure would be treatment of choice in future clinical application. Our results suggest ultrasound-triggered microbubble cavitation can be repeatable and is promising for the local control of non-muscle invasive bladder cancer.

  4. Gas chromatography-flame ionization determination of benzaldehyde in non-steroidal anti-inflammatory drug injectable formulations using new ultrasound-assisted dispersive liquid-liquid micro extraction

    International Nuclear Information System (INIS)

    Mashayekhi, H.A.; Pourshamsian, K.

    2012-01-01

    Summary: In this study, simple and efficient ultrasound-assisted dispersive liquid-liquid micro extraction combined with gas chromatography (GC) was developed for the preconcentration and determination of benzaldehyde in injectable formulations of the non-steroidal anti-inflammatory drugs, diclofenac, Vitamin B-complex and Voltaren injection solutions. Fourteen microliters of toluene was injected slowly into 10 mL home-designed centrifuge glass vial containing an aqueous sample without salt addition that was located inside the ultrasonic water bath. The formed emulsion was centrifuged and 2 macro L of separated toluene was injected into a gas chromatographic system equipped with a flame ionization detector (GC-FID) for analysis. Several factors influencing the extraction efficiency as the nature and volume of organic solvent, extraction temperature, ionic strength and centrifugation time were investigated and optimized. Using optimum extraction conditions a detection limit of 0.3 macro g L/sup -1/ and a good linearity in a calibration range of 2.0-1000 macro g L/sup -1/ were achieved for analyte. This proposed method was successfully applied to the analysis of benzaldehyde in three injection formulations and relative standard deviation (RSD) of analysis (n=3), before spiking with standard benzaldehyde were 3.3, 2.0 and 1.3% for Na-diclofenac, vitamin B-complex and voltaren, respectively and after spiking of standard benzaldehyde (0.3 mg L/sup -1/), the RSD were 6.5, 3.6 and 2.8% for Na-diclofenac, vitamin B-complex and voltaren, respectively. (author)

  5. Ligandless, ion pair-based and ultrasound assisted emulsification solidified floating organic drop microextraction for simultaneous preconcentration of ultra-trace amounts of gold and thallium and determination by GFAAS.

    Science.gov (United States)

    Fazelirad, Hamid; Taher, Mohammad Ali

    2013-01-15

    In the present work, a new, simple and efficient method for simultaneous preconcentration of ultra-trace amounts of gold and thallium is developed using an ion pair based-ultrasound assisted emulsification-solidified floating organic drop microextraction procedure before graphite furnace atomic absorption spectrometry determination. This methodology was used to preconcentrate the ion pairs formed between AuCl(4)(-) and TlCl(4)(-) and [C(23)H(42)]N(+) in a microliter-range volume of 1-undecanol. Several factors affecting the microextraction efficiency, such as HCl volume, type and volume of extraction solvent, sonication time, sample volume, temperature, ionic strength and [C(23)H(42)]NCl volume were investigated and optimized. Under the optimized conditions, the enrichment factor of 441 and 443 and calibration graphs of 2.2-89 and 22.2-667 ng L(-1) for gold and thallium were obtained, respectively. The intra- and inter-day precision of ± 4.4 and ± 4.9% for Au and ± 4.8 and ± 5.4% for Tl were obtained. The detection limit was 0.66 ng L(-1) for Au and 4.67 ng L(-1) for Tl. The results show that the liquid-liquid pretreatment using ion pair forming, is sensitive, rapid, simple and safe method for the simultaneous preconcentration of gold and thallium. The method was successfully applied for determination of gold and thallium in natural water and hair samples. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Ultrasound assisted enhancement in natural dye extraction from beetroot for industrial applications and natural dyeing of leather.

    Science.gov (United States)

    Sivakumar, Venkatasubramanian; Anna, J Lakshmi; Vijayeeswarri, J; Swaminathan, G

    2009-08-01

    There is a growing demand for eco-friendly/non-toxic colorants, specifically for health sensitive applications such as coloration of food and dyeing of child textile/leather garments. Recently, dyes derived from natural sources for these applications have emerged as an important alternative to potentially harmful synthetic dyes and pose need for suitable effective extraction methodologies. The present paper focus on the influence of process parameters for ultrasound assisted leaching of coloring matter from plant materials. In the present work, extraction of natural dye from beetroot using ultrasound has been studied and compared with static/magnetic stirring as a control process at 45 degrees C. The influence of process parameters on the extraction efficiency such as ultrasonic output power, time, pulse mode, effect of solvent system and amount of beetroot has been studied. The use of ultrasound is found to have significant improvement in the extraction efficiency of colorant obtained from beetroot. Based on the experiments it has been found that a mixture of 1:1 ethanol-water with 80W ultrasonic power for 3h contact time provided better yield and extraction efficiency. Pulse mode operation may be useful in reducing electrical energy consumption in the extraction process. The effect of the amount of beetroot used in relation to extraction efficiency has also been studied. Two-stage extraction has been studied and found to be beneficial for improving the yield for higher amounts of beetroot. Significant 8% enhancement in % yield of colorant has been achieved with ultrasound, 80W as compared to MS process both using 1:1 ethanol-water. The coloring ability of extracted beet dye has been tested on substrates such as leather and paper and found to be suitable for dyeing. Ultrasound is also found to be beneficial in natural dyeing of leather with improved rate of exhaustion. Both the dyed substrates have better color values for ultrasonic beet extract as inferred from

  7. The endoscopic ultrasound-assisted Rendez-Vous technique for treatment of recurrent pancreatitis due to pancreas divisum and ansa pancreatica

    Directory of Open Access Journals (Sweden)

    Sergio López-Durán

    Full Text Available Endoscopic treatment of pancreatic ductal malformations causing recurrent acute pancreatitis, such as pancreas divisum or ansa pancreatica, is mainly based on the sphincterotomy of the minor papilla. However, the technical complexity of conventional endoscopic retrograde cholangiopancreatography (ERCP is increased in patients presenting anatomical variants like these and it may be unsuccessful. We report the case of a pancreas divisum combined with ansa pancreatica and describe the cannulation and sphincterotomy of the minor papilla using an ultrasound-assisted Rendez-Vous technique.

  8. Progress in Separation of Gases by Permeation and Liquids by Pervaporation Using Ionic Liquids: A Review

    OpenAIRE

    Kárászová, M. (Magda); Kačírková, M. (Marie); Friess, K.; Izák, P. (Pavel)

    2014-01-01

    The effective separation of gases and liquids by membranes containing ionic liquids actually belongs to one of the challenging topics in membrane community. During last decade, a plenty of new kinds of ionic liquids (IL), their combinations, different types of polymerized ionic liquids and polymer–IL composite membranes were developed and tested. This review summarizes the most important achievements and findings connected with the ionic liquid based membranes research and tries to answer h...

  9. Learning Ionic

    CERN Document Server

    Ravulavaru, Arvind

    2015-01-01

    This book is intended for those who want to learn how to build hybrid mobile applications using Ionic. It is also ideal for people who want to explore theming for Ionic apps. Prior knowledge of AngularJS is essential to complete this book successfully.

  10. Metamaterial Behavior of Polymer Nanocomposites Based on Polypropylene/Multi-Walled Carbon Nanotubes Fabricated by Means of Ultrasound-Assisted Extrusion

    Directory of Open Access Journals (Sweden)

    Juan C. Pérez-Medina

    2016-11-01

    Full Text Available Metamaterial behavior of polymer nanocomposites (NCs based on isotactic polypropylene (iPP and multi-walled carbon nanotubes (MWCNTs was investigated based on the observation of a negative dielectric constant (ε′. It is demonstrated that as the dielectric constant switches from negative to positive, the plasma frequency (ωp depends strongly on the ultrasound-assisted fabrication method, as well as on the melt flow index of the iPP. NCs were fabricated using ultrasound-assisted extrusion methods with 10 wt % loadings of MWCNTs in iPPs with different melt flow indices (MFI. AC electrical conductivity (σ(AC as a function of frequency was determined to complement the electrical classification of the NCs, which were previously designated as insulating (I, static-dissipative (SD, and conductive (C materials. It was found that the SD and C materials can also be classified as metamaterials (M. This type of behavior emerges from the negative dielectric constant observed at low frequencies although, at certain frequencies, the dielectric constant becomes positive. Our method of fabrication allows for the preparation of metamaterials with tunable ωp. iPP pure samples show only positive dielectric constants. Electrical conductivity increases in all cases with the addition of MWCNTs with the largest increases observed for samples with the highest MFI. A relationship between MFI and the fabrication method, with respect to electrical properties, is reported.

  11. Determination of total arsenic and arsenic(III) in phosphate fertilizers by hydride generation atomic absorption spectrometry after ultrasound-assisted extraction based on a control acid media.

    Science.gov (United States)

    Rezende, Helen Cristine; Coelho, Nivia Maria Melo

    2014-01-01

    An ultrasound-assisted extraction procedure was developed for determination of inorganic arsenic (As) in phosphate fertilizer by hydride generation atomic absorption spectrometry. The variables that affect the hydride generation step were optimized, including the reducer, acid, sample flow rate, and concentrations of the acid and reducer. The determination of As(lll) was performed through the simple control of solution pH with a 0.5 M citric acid-sodium citrate buffer solution at pH 4.5, and total As was determined after a pre-reduction reaction with 1.0% (w/v) thiourea. Ultrasound-assisted acid extraction was performed, and the parameters sonication time and acid and Triton X-114 concentrations were optimized using a 23 factorial design and central composite design. LODs for As(lll) and total As were 0.029 and 0.022 microg/L, respectively. The accuracy of the method was confirmed with certified reference materials. The method was successfully applied in the determination of inorganic As in phosphate fertilizer samples.

  12. Optimization of ultrasound-assisted extraction to obtain mycosterols from Agaricus bisporus L. by response surface methodology and comparison with conventional Soxhlet extraction.

    Science.gov (United States)

    Heleno, Sandrina A; Diz, Patrícia; Prieto, M A; Barros, Lillian; Rodrigues, Alírio; Barreiro, Maria Filomena; Ferreira, Isabel C F R

    2016-04-15

    Ergosterol, a molecule with high commercial value, is the most abundant mycosterol in Agaricus bisporus L. To replace common conventional extraction techniques (e.g. Soxhlet), the present study reports the optimal ultrasound-assisted extraction conditions for ergosterol. After preliminary tests, the results showed that solvents, time and ultrasound power altered the extraction efficiency. Using response surface methodology, models were developed to investigate the favourable experimental conditions that maximize the extraction efficiency. All statistical criteria demonstrated the validity of the proposed models. Overall, ultrasound-assisted extraction with ethanol at 375 W during 15 min proved to be as efficient as the Soxhlet extraction, yielding 671.5 ± 0.5mg ergosterol/100 g dw. However, with n-hexane extracts with higher purity (mg ergosterol/g extract) were obtained. Finally, it was proposed for the removal of the saponification step, which simplifies the extraction process and makes it more feasible for its industrial transference. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Simple method for the determination of personal care product ingredients in lettuce by ultrasound-assisted extraction combined with solid-phase microextraction followed by GC-MS.

    Science.gov (United States)

    Cabrera-Peralta, Jerónimo; Peña-Alvarez, Araceli

    2018-05-01

    A simple method for the simultaneous determination of personal care product ingredients: galaxolide, tonalide, oxybenzone, 4-methylbenzyliden camphor, padimate-o, 2-ethylhexyl methoxycinnamate, octocrylene, triclosan, and methyl triclosan in lettuce by ultrasound-assisted extraction combined with solid-phase microextraction followed by gas chromatography with mass spectrometry was developed. Lettuce was directly extracted by ultrasound-assisted extraction with methanol, this extract was combined with water, extracted by solid-phase microextraction in immersion mode, and analyzed by gas chromatography with mass spectrometry. Good linear relationships (25-250 ng/g, R 2  > 0.9702) and low detection limits (1.0-25 ng/g) were obtained for analytes along with acceptable precision for almost all analytes (RSDs < 20%). The validated method was applied for the determination of personal care product ingredients in commercial lettuce and lettuces grown in soil and irrigated with the analytes, identifying the target analytes in leaves and roots of the latter. This procedure is a miniaturized and environmentally friendly proposal which can be a useful tool for quality analysis in lettuce. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Ultrasound-assisted oxidative desulfurization process of liquid fuel by phosphotungstic acid encapsulated in a interpenetrating amine-functionalized Zn(II)-based MOF as catalyst.

    Science.gov (United States)

    Afzalinia, Ahmad; Mirzaie, Abbas; Nikseresht, Ahmad; Musabeygi, Tahereh

    2017-01-01

    In this work, ultrasound-assisted oxidative desulfurization (UAOD) of liquid fuels performed with a novel heterogeneous highly dispersed Keggin-type phosphotungstic acid (H 3 PW 12 O 40 , PTA) catalyst that encapsulated into an amino-functionalized MOF (TMU-17-NH 2 ). The prepared composite exhibits high catalytic activity and reusability in oxidative desulfurization of model fuel. Ultrasound-assisted oxidative desulfurization (UAOD) is a new way to performed oxidation reaction of sulfur-contain compounds rapidly, economically, environment-friendly and safely, under mild conditions. Ultrasound waves can be apply as an efficient tool to decrease the reaction time and improves oxidative desulfurization system performance. PTA@TMU-17-NH 2 could be completely performed desulfurization of the model oil by 20mg of catalyst, O/S molar ratio of 1:1 in presence of MeCN as extraction solvent. The obtained results indicated that the conversions of DBT to DBTO 2 achieve 98% after 15min in ambient temperature. In this work, we prepared TMU-17-NH 2 and PTA/TMU-17-NH 2 composite by ultrasound irradiation for first time and employed in UAOD process. Prepared catalyst exhibit an excellent reusability without PTA leaching and loss of activity. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  15. Metamaterial Behavior of Polymer Nanocomposites Based on Polypropylene/Multi-Walled Carbon Nanotubes Fabricated by Means of Ultrasound-Assisted Extrusion

    Science.gov (United States)

    Pérez-Medina, Juan C.; Waldo-Mendoza, Miguel A.; Cruz-Delgado, Víctor J.; Quiñones-Jurado, Zoe V.; González-Morones, Pablo; Ziolo, Ronald F.; Martínez-Colunga, Juan G.; Soriano-Corral, Florentino; Avila-Orta, Carlos A.

    2016-01-01

    Metamaterial behavior of polymer nanocomposites (NCs) based on isotactic polypropylene (iPP) and multi-walled carbon nanotubes (MWCNTs) was investigated based on the observation of a negative dielectric constant (ε′). It is demonstrated that as the dielectric constant switches from negative to positive, the plasma frequency (ωp) depends strongly on the ultrasound-assisted fabrication method, as well as on the melt flow index of the iPP. NCs were fabricated using ultrasound-assisted extrusion methods with 10 wt % loadings of MWCNTs in iPPs with different melt flow indices (MFI). AC electrical conductivity (σ(AC)) as a function of frequency was determined to complement the electrical classification of the NCs, which were previously designated as insulating (I), static-dissipative (SD), and conductive (C) materials. It was found that the SD and C materials can also be classified as metamaterials (M). This type of behavior emerges from the negative dielectric constant observed at low frequencies although, at certain frequencies, the dielectric constant becomes positive. Our method of fabrication allows for the preparation of metamaterials with tunable ωp. iPP pure samples show only positive dielectric constants. Electrical conductivity increases in all cases with the addition of MWCNTs with the largest increases observed for samples with the highest MFI. A relationship between MFI and the fabrication method, with respect to electrical properties, is reported. PMID:28774042

  16. Optimization of ultrasound-assisted extraction of crude oil from winter melon (Benincasa hispida) seed using response surface methodology and evaluation of its antioxidant activity, total phenolic content and fatty acid composition.

    Science.gov (United States)

    Bimakr, Mandana; Rahman, Russly Abdul; Taip, Farah Saleena; Adzahan, Noranizan Mohd; Sarker, Md Zaidul Islam; Ganjloo, Ali

    2012-10-08

    In the present study, ultrasound-assisted extraction of crude oil from winter melon seeds was investigated through response surface methodology (RSM). Process variables were power level (25-75%), temperature (45-55 °C) and sonication time (20-40 min). It was found that all process variables have significant (p yield (108.62 mg-extract/g-dried matter). The antioxidant activity, total phenolic content and fatty acid composition of extract obtained under optimized conditions were determined and compared with those of oil obtained by the Soxhlet method. It was found that crude extract yield (CEY) of ultrasound-assisted extraction was lower than that of the Soxhlet method, whereas antioxidant activity and total phenolic content of the extract obtained by ultrasound-assisted extraction were clearly higher than those of the Soxhlet extract. Furthermore, both extracts were rich in unsaturated fatty acids. The major fatty acids of the both extracts were linoleic acid and oleic acid.

  17. Recent developments in biocatalysis in multiphasic ionic liquid reaction systems.

    Science.gov (United States)

    Meyer, Lars-Erik; von Langermann, Jan; Kragl, Udo

    2018-06-01

    Ionic liquids are well known and frequently used 'designer solvents' for biocatalytic reactions. This review highlights recent achievements in the field of multiphasic ionic liquid-based reaction concepts. It covers classical biphasic systems including supported ionic liquid phases, thermo-regulated multi-component solvent systems (TMS) and polymerized ionic liquids. These powerful concepts combine unique reaction conditions with a high potential for future applications on a laboratory and industrial scale. The presence of a multiphasic system simplifies downstream processing due to the distribution of the catalyst and reactants in different phases.

  18. Thioimidazolium Ionic Liquids as Tunable Alkylating Agents.

    Science.gov (United States)

    Guterman, Ryan; Miao, Han; Antonietti, Markus

    2018-01-19

    Alkylating ionic liquids based on the thioimidazolium structure combine the conventional properties of ionic liquids, including low melting point and nonvolatility, with the alkylating function. Alkyl transfer occurs exclusively from the S-alkyl position, thus allowing for easy derivatization of the structure without compromising specificity. We apply this feature to tune the electrophilicty of the cation to profoundly affect the reactivity of these alkylating ionic liquids, with a caffeine-derived compound possessing the highest reactivity. Anion choice was found to affect reaction rates, with iodide anions assisting in the alkylation reaction through a "shuttling" process. The ability to tune the properties of the alkylating agent using the toolbox of ionic liquid chemistry highlights the modular nature of these compounds as a platform for alkylating agent design and integration in to future systems.

  19. A possible general mechanism for ultrasound-assisted extraction (UAE) suggested from the results of UAE of chlorogenic acid from Cynara scolymus L. (artichoke) leaves.

    Science.gov (United States)

    Saleh, I A; Vinatoru, M; Mason, T J; Abdel-Azim, N S; Aboutabl, E A; Hammouda, F M

    2016-07-01

    The use of ultrasound-assisted extraction (UAE) for the extraction of chlorogenic acid (CA) from Cynara scolymus L., (artichoke) leaves using 80% methanol at room temperature over 15 min gave a significant increase in yield (up to a 50%) compared with maceration at room temperature and close to that obtained by boiling over the same time period. A note of caution is introduced when comparing UAE with Soxhlet extraction because, in the latter case, the liquid entering the Soxhlet extractor is more concentrated in methanol (nearly 100%) that the solvent in the reservoir (80% methanol) due to fractionation during distillation. The mechanism of UAE is discussed in terms of the effects of cavitation on the swelling index, solvent diffusion and the removal of a stagnant layer of solvent surrounding the plant material. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Microwave-assisted extraction of coumarin and related compounds from Melilotus officinalis (L.) Pallas as an alternative to Soxhlet and ultrasound-assisted extraction.

    Science.gov (United States)

    Martino, Emanuela; Ramaiola, Ilaria; Urbano, Mariangela; Bracco, Francesco; Collina, Simona

    2006-09-01

    Soxhlet extraction, ultrasound-assisted extraction (USAE) and microwaves-assisted extraction (MAE) in closed system have been investigated to determine the content of coumarin, o-coumaric and melilotic acids in flowering tops of Melilotus officinalis. The extracts were analyzed with an appropriate HPLC procedure. The reproducibility of extraction and of chromatographic analysis was proved. Taking into account the extraction yield, the cost and the time, we studied the effects of extraction variables on the yield of the above-mentioned compounds. Better results were obtained with MAE (50% v/v aqueous ethanol, two heating cycles of 5 min, 50 degrees C). On the basis of the ratio extraction yield/extraction time, we therefore propose MAE as the most efficient method.

  1. Maceration of Extra Virgin Olive Oil with Common Aromatic Plants Using Ultrasound-Assisted Extraction: An UV-Vis Spectroscopic Investigation

    Directory of Open Access Journals (Sweden)

    Ozren Jović

    2018-01-01

    Full Text Available Rosemary (Rosmarinus officinalis, garden sage (Salvia officinalis, summer savory (Satureja hortensis, laurel (Laurus nobilis, and other aromatic plants were put in olive oil and exposed to ultrasounds for different duration. Filtrated oils were dissolved in cyclohexane, and UV-Vis measurements were carried out. Absorbance values corresponding to chlorophylls, carotenoids, flavonoids (370 nm, and polyphenols (around 300 nm were measured. In addition, for some samples, total phenols were determined using Folin-Denis reagent and compared with the similar maceration procedure in water solvent (instead of olive oil. Maceration without ultrasound in olive oil for each plant was also compared with ultrasound-assisted extraction. The results show that significant amount of aromatic content can be extracted in olive oil by applying ultrasounds for only few minutes, especially for Salvia officinalis powder. The use of UV-Vis measurements is simple but enough to examine the extent of phenol content extraction through such maceration procedure.

  2. Biocompatibility assessment of graphene oxide-hydroxyapatite coating applied on TiO2 nanotubes by ultrasound-assisted pulse electrodeposition.

    Science.gov (United States)

    Fathyunes, Leila; Khalil-Allafi, Jafar; Sheykholeslami, Seyed Omid Reza; Moosavifar, Maryam

    2018-06-01

    In this study, the ultrasound-assisted pulse electrodeposition was introduced to fabricate the graphene oxide (GO)-hydroxyapatite (HA) coating on TiO 2 nanotubes. The results of the X-ray diffraction (XRD), Fourier Transform Infrared spectroscope (FTIR), Transmission Electron Microscope (TEM) and micro-Raman spectroscopy showed the successful synthesis of GO. The Scanning Electron Microscope (SEM) images revealed that in the presence of ultrasonic waves and GO sheets a more compact HA-based coating with refined microstructure could be formed on the pretreated titanium. The results of micro-Raman analysis confirmed the successful incorporation of the reinforcement filler of GO into the coating electrodeposited by the ultrasound-assisted method. The FTIR analysis showed that the GO-HA coating was consisted predominantly of the B-type carbonated HA (CHA) phase. The pretreatment of the substrate and incorporation of the GO sheets into the HA coating had a significant effect on improving the bonding strength at the coating-substrate interface. Moreover, the results of the fibroblast cell culture and 3‑(4,5‑dimethylthiazolyl‑2)‑2, 5‑diphenyltetrazolium bromide (MTT) assay after 2 days demonstrated a higher percentage of cell activity for the GO-HA coated sample. Finally, the 7-day exposure to simulated body fluid (SBF) showed a faster rate of apatite precipitation on the GO-HA coating, as compared to the HA coating and pretreated titanium. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Synthesis and characterization of ultrasound assisted “graphene oxide–magnetite” hybrid, and investigation of its adsorption properties for Sr(II) and Co(II) ions

    Energy Technology Data Exchange (ETDEWEB)

    Tayyebi, Ahmad; Outokesh, Mohammad, E-mail: Outokesh@sharif.edu; Moradi, Shahab; Doram, Amir

    2015-10-30

    Graphical abstract: - Highlights: • Narrow size magnetite NPs were synthesized by ultrasound assisted coprecipitaion method. • A formation mechanism for deposition of magnetite NPs on graphene oxide is proposed. • The formation mechanism supported using X-ray photoelectron spectroscopy analysis. • The modified Langevin equation was used for size estimation of magnetite NPs on M–GO. • Adsorption properties of M–GO for Co(II) and Sr(II) were investigated. - Abstract: Magnetite nanoparticles with a size distribution of 15–21 nm were synthesized and decorated onto surface of graphene oxide by ultrasound assisted precipitation. Size and size distribution of the obtained M–GO hybrid were appreciably finer than the hybrids prepared by stirring method. M–GO is a superparamagnetic material with saturation magnetization of 31 emu g{sup −1}. The Langevin equation was successfully applied for estimation of size of Fe{sub 3}O{sub 4} nanoparticles in M–GO hybrid, with maximum error of 17.5%. The study put forward a formation mechanism for M–GO, based on instrumental analyses. Adsorption isotherms of Sr{sup 2+} and Co{sup 2+} ions, which were fitted by Langmuir monolayer model, displayed two-fold higher capacity for Co{sup 2+} ions, presumably due to its similarity to Fe{sup 2+} (of Fe{sub 3}O{sub 4} component). Uptake of both Co{sup 2+} and Sr{sup 2+} ions were endothermic, and spontaneous, however the former proceeded through inner-shell complex formation, while the latter took place via ion exchange mechanism. Rate of adsorption of Co{sup 2+} was faster, but for both ions, chemical reaction was the rate determining step. Sorption of Sr{sup 2+} and Co{sup 2+} ions greatly increased at pHs above 5, where (1) surface zeta potential changed its sign, and (2) deprotonating reactions at the surface became complete.

  4. Fe(II)–Al(III) layered double hydroxides prepared by ultrasound-assisted co-precipitation method for the reduction of bromate

    International Nuclear Information System (INIS)

    Zhong, Yu; Yang, Qi; Luo, Kun; Wu, Xiuqiong; Li, Xiaoming; Liu, Yang; Tang, Wangwang; Zeng, Guangming; Peng, Bo

    2013-01-01

    Highlights: ► Fe(II)–Al(III) LDHs were synthesized by ultrasound-assisted co-precipitation method. ► The Fe–Al (30 min) exhibited highly reduction reactivity on bromate. ► Pseudo-first-order model described the experimental data well. ► The mechanisms of bromate removal were proposed. -- Abstract: Bromate is recognized as an oxyhalide disinfection byproduct in drinking water. In this paper, Fe(II)–Al(III) layered double hydroxides (Fe–Al LDHs) prepared by the ultrasound-assisted co-precipitation method were used for the reduction of bromate in solution. The Fe–Al LDHs particles were characterized by X-ray diffractometer, scanning electron microscopy and thermogravimetry–differential scanning calorimetry. It was found that ultrasound irradiation assistance promoted the formation of the hydrotalcite-like phase and then improved the removal efficiency of bromate. In addition, the effects of solid-to-solution ratio, contact time, initial bromate concentration, initial pH, coexisting anions on the bromate removal were investigated. The results showed the bromate with an initial concentration of 1.56 μmol/L could be completely removed from solution by Fe–Al LDHs within 120 min. When the initial bromate concentration was 7.81 μmol/L, the Fe–Al LDHs with irradiation time of 30 min exhibited the optimum removal efficiency and the bromate removal capacity (q e ) was 6.80 μmol/g. In addition, the appearance of sulfate and production of bromide were observed simultaneously in this process, which suggested that ion-exchange between sulfate and bromate, and the reduction of bromate to bromide by Fe 2+ were the main mechanisms responsible for the bromate removal by Fe–Al LDHs

  5. Optimization of ultrasound-assisted aqueous two-phase system extraction of polyphenolic compounds from Aronia melanocarpa pomace by response surface methodology.

    Science.gov (United States)

    Xu, Yan-Yang; Qiu, Yang; Ren, Hui; Ju, Dong-Hu; Jia, Hong-Lei

    2017-03-16

    Aronia melanocarpa berries are abundant in polyphenolic compounds. After juice production, the pomace of pressed berries still contains a substantial amount of polyphenolic compounds. For efficient utilization of A. melanocarpa berries and the enhancement of polyphenolic compound yields in Aronia melanocarpa pomace (AMP), total phenolics (TP) and total flavonoids (TF) from AMP were extracted, using ultrasound-assisted aqueous two-phase system (UAE-ATPS) extraction method. First, the influences of ammonium sulfate concentration, ethanol-water ratio, ultrasonic time, and ultrasonic power on TP and TF yields were investigated. On this basis, process variables such as ammonium sulfate concentration (0.30-0.35 g mL -1 ), ethanol-water ratio (0.6-0.8), ultrasonic time (40-60 min), and ultrasonic power (175-225 W) were further optimized by implementing Box-Benhnken design with response surface methodology. The experimental results showed that optimal extraction conditions of TP from AMP were as follows: ammonium sulfate concentration of 0.324 g mL -1 , ethanol-water ratio of 0.69, ultrasonic time of 52 min, and ultrasonic power of 200 W. Meanwhile, ammonium sulfate concentration of 0.320 g mL -1 , ethanol-water ratio of 0.71, ultrasonic time of 50 min, and ultrasonic power of 200 W were determined as optimum extraction conditions of TF in AMP. Experimental validation was performed, where TP and TF yields reached 68.15 ± 1.04 and 11.67 ± 0.63 mg g -1 , respectively. Close agreement was found between experimental and predicted values. Overall, the present results demonstrated that ultrasound-assisted aqueous two-phase system extraction method was successfully used to extract total phenolics and flavonoids in A. melanocarpa pomace.

  6. Ultrasound assisted dispersion of different amount of Ni over ZSM-5 used as nanostructured catalyst for hydrogen production via CO2 reforming of methane

    International Nuclear Information System (INIS)

    Vafaeian, Yaser; Haghighi, Mohammad; Aghamohammadi, Sogand

    2013-01-01

    Graphical abstract: A series of Ni/ZSM-5 nanocatalysts with different amount of Ni were prepared via ultrasound assisted method and characterized with XRD, FESEM, TEM, BET and FTIR techniques. The research deals with catalyst development for dry reforming of methane with the aim of reaching the most stable catalyst specifically over nano-sized catalysts. About more than 99% of Ni particles size is less than 100 nm for the sample prepared with 8% Ni, which is essential to the relative suppression of the carbon formation on catalysts. Catalyst prepared with 8% Ni content showed superior activity in process expected due to its better catalytic properties. - Highlights: • Using ZSM-5 zeolite in dry reforming of methane. • Employing ultrasound energy in synthesis of Ni/ZSM-5 nanocatalyst. • Enhancement of Ni particles size to meet desired catalyst at lower amount of Ni loading. • Dry reforming of methane over Ni/ZSM-5 nanocatalyst with different Ni-loading. • Superior activity of Ni/ZSM-5 nanocatalyst synthesized with 8% Ni content. - Abstract: Carbon dioxide reforming of methane is an interesting route for synthesis gas production especially over nanostructured catalysts. The present research deals with nanocatalyst development by sonochemical method for dry reforming of methane with the aim of reaching the most efficient nanocatalyst. Effect of Ni metal content, one of the most significant variables, on the properties of the ZSM-5 supported nanocatalysts was taken into account. The Ni/ZSM-5 nanocatalysts were prepared via assisted traditional impregnation method via ultrasound irradiation and characterized with XRD, FESEM, TEM, BET and FTIR techniques. Comparison of XRD patterns implies that the peaks related to NiO become sharper by increasing metal content over the support. In the case of nanocatalysts with lower metal content (3% and 8%), the beneficial influence of ultrasound assisted procedure become more pronounced and the observed reduction in

  7. Ionic thermometers

    International Nuclear Information System (INIS)

    Strnad, M.

    1975-01-01

    An original method of temperature measurement based on conductivity changes near the phase transition point of ionic compounds and suitable for the range from 200 to 700 0 C according to the thermometric compound used, is given. By choosing between two approaches it is posible to evaluate either a discrete value of temperature or continuous measurement in a range to about 50 0 C below the phase transition point of thermometric compounds. The extreme nonlinearity of conductivity of the chosen group of ionic crystals used as well as the technical applications developed in the laboratories have not previously been published. The aim of the research is the application of this measuring method for temperature indication in nuclear reactors. Preliminary tests in radiation fields in an experimental reactor are yielding a real hope in this direction. (author)

  8. Ionic polarization

    International Nuclear Information System (INIS)

    Mahan, G.D.

    1992-01-01

    Ferroelectricity occurs in many different kinds of materials. Many of the technologically important solids, which are ferroelectric, can be classified as ionic. Any microscopic theory of ferroelectricity must contain a description of local polarization forces. We have collaborated in the development of a theory of ionic polarization which is quite successful. Its basic assumption is that the polarization is derived from the properties of the individual ions. We have applied this theory successfully to diverse subjects as linear and nonlinear optical response, phonon dispersion, and piezoelectricity. We have developed numerical methods using the local Density approximation to calculate the multipole polarizabilities of ions when subject to various fields. We have also developed methods of calculating the nonlinear hyperpolarizability, and showed that it can be used to explain light scattering experiments. This paper elaborates on this polarization theory

  9. Modified Ionic Liquid-Based Phase Change Materials as Effective Heat Exchangers, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Future manned spacecraft venturing into deep space will require sophisticated thermal control systems to protect against extreme environments ranging from direct...

  10. Modified Ionic Liquid-Based Phase Change Materials as Effective Heat Exchangers, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Future manned mission venturing into deep space will require sophisticated thermal control systems to protect against extreme environments ranging from direct...

  11. Modified Ionic Liquid-Based High-Performance Lubricants for Robotic Operations, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA requires a highly efficient lubrication system for robotic operations, which will withstand very low temperatures (20 K) and other rigors of outer space and...

  12. Modified Ionic Liquid-Based High-Performance Lubricants for Robotic Operations, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA needs an advanced lubrication solution for its future robotic systems and planetary surface assets. The required lubrication technology must offer...

  13. Determination of Pb in river water samples by inductively coupled plasma optical emission spectrometry after ultrasound-assisted co-precipitation with manganese dioxide

    International Nuclear Information System (INIS)

    Sousa Bispo, Marcia; Santos da Boa Morte, Elane; Korn das Gracas Andrade, Maria; Sena Gomes Teixeira, Leonardo; Korn, Mauro; Costa, Antonio Celso Spinola

    2005-01-01

    A simple and efficient procedure for separation and pre-concentration using ultrasound-assisted co-precipitation with manganese dioxide was developed for Pb determination by inductively coupled plasma optical emission spectrometry (ICP OES). The optimization process was carried out using a two-level factorial design and a Doehlert matrix. Three variables (i.e. concentration of oxidizing solution-KMnO 4 , concentration of MnSO 4 solution and time of ultrasonic irradiation) were used as factors in the optimization. The recoveries, based on the analysis of spiked samples, were between 90% and 105%, and the precision was ≤ 5%. The detection limit and quantification limit for Pb determination were 3.2 and 10.7 μg L -1 , respectively. The proposed method was applied for the determination of Pb in water samples from a river heavily polluted by industrial effluents. The recovery measured by analyte addition technique showed that the proposed pre-concentration method had good accuracy

  14. Evaluation of ultrasound-assisted in situ sorbent formation solid-phase extraction method for determination of arsenic in water, food and biological samples.

    Science.gov (United States)

    Ezoddin, Maryam; Majidi, Behrooz; Abdi, Khosrou

    2015-01-01

    A simple and rapid ultrasound-assisted in situ sorbent formation solid-phase extraction (UAISFSPE) coupled with electrothermal atomic absorption spectrometry detection (ET-AAS) was developed for preconcentration and determination of arsenic (As) in various samples. A small amount of cationic surfactant is dissolved in the aqueous sample containing As ions, which were complexed by ammonium pyrrolidinedithiocarbamate After shaking, a little volume of hexafluorophosphate (NaPF6) as an ion-pairing agent was added into the solution by a microsyringe. Due to the interaction between surfactant and ion-pairing agent, solid particles are formed. The alkyl groups of the surfactant in the solid particles strongly interact with the hydrophobic groups of analytes and become bound. Sonication aids the dispersion of the sorbent into the sample solution and mass transfer of the analyte into the sorbent, thus reducing the extraction time. The solid particles are centrifuged, and the sedimented particles can be dissolved in an appropriate solvent to recover the absorbed analyte. After separation, total arsenic (As(III) and As(V)) was determined by ET-AAS. Several experimental parameters were investigated and optimized. A detection limit of 7 ng L(-1) with preconcentration factor of 100 and relative standard deviation for 10 replicate determinations of 0.1 µg L(-1) As(III) were 4.5% achieved. Consequently, the method was applied to the determination of arsenic in certified reference materials, water, food and biological samples with satisfactory results.

  15. Ultrasound-assisted extraction of fructans from agave (Agave tequilana Weber var. azul at different ultrasound powers and solid-liquid ratios

    Directory of Open Access Journals (Sweden)

    Miguel Ángel SÁNCHEZ-MADRIGAL

    Full Text Available Abstract The effects of ultrasound-assisted extraction (UAE at different ultrasound power densities (UPDs; 40, 80, and 120 mW/mL and solid:liquid (S:L ratio (1:2, 1:3, and 1:6 on the extraction of carbohydrates from Agave tequilana plant of different ages were evaluated. Extracts obtained (6- and 7-year-old plant were analyzed in the yield of carbohydrates (YC, fructan (FRU content, simple sugars, fructan profile and the average degree of polymerization (DPn. UPD, S:L ratio, and plant age all affected YC, FRU, and DPn. Maximum YC and FRU were obtained from the older agave with UPD and S:L ratio of 120 mW/mL and 1:6, respectively; while glucose, fructose, and sucrose were highly released from the younger plant. Agave of 7-year-old presented the highest DPn. Fructan degradation occurred at high UPD, increasing the simple sugars and decreasing the DPn. Thermal-traditional extraction without sonication caused more fructan degradation; and overall, ultrasound enhanced fructan extraction and minimized fructan damage, representing a technological alternative for fructan extraction from agave.

  16. Coupling continuous ultrasound-assisted extraction, preconcentration and flame atomic absorption spectrometric detection for the determination of cadmium and lead in mussel samples

    International Nuclear Information System (INIS)

    Yebra-Biurrun, M.C.; Cancela-Perez, S.; Moreno-Cid-Barinaga, A.

    2005-01-01

    Continuous ultrasound-assisted extraction has been coupled with preconcentration and flame atomic absorption spectrometry for the determination of cadmium and lead in mussel samples. Experimental designs were used for the optimisation of the leaching and preconcentration steps. The use of diluted nitric acid as extractant in the continuous mode at a flow rate of 3.5 ml min -1 and room temperature was sufficient for quantitative extraction of these trace metals. A minicolumn containing a chelating resin (Chelite P, with aminomethylphosphoric acid groups) was proved as an excellent material for the quantitative preconcentration of cadmium and lead prior to their flame atomic absorption detection. A flow injection manifold was used as interface for coupling the three analytical steps, which allowed the automation of the whole analytical process. A good precision of the whole procedure (2.0 and 2.3%), high enrichment factors (20.5 and 11.8) and a detection limit of 0.011 and 0.25 μg g -1 for cadmium and lead, respectively, were obtained for 80 mg of sample. The sample throughputs were ca. 16 and 14 samples h -1 for cadmium and lead, respectively. The accuracy of the analytical procedures was verified by using a standard reference material (BCR 278-R, mussel tissue) and the results were in good agreement with the certified values. The method was successfully applied to the determination of trace amounts of cadmium and lead in mussel samples from the coast of Galicia (NW, Spain)

  17. Green ultrasound-assisted extraction of carotenoids based on the bio-refinery concept using sunflower oil as an alternative solvent.

    Science.gov (United States)

    Li, Ying; Fabiano-Tixier, Anne Sylvie; Tomao, Valérie; Cravotto, Giancarlo; Chemat, Farid

    2013-01-01

    A green, inexpensive and easy-to-use method for carotenoids extraction from fresh carrots assisted by ultrasound was designed in this work. Sunflower oil was applied as a substitute to organic solvents in this green ultrasound-assisted extraction (UAE): a process which is in line with green extraction and bio-refinery concepts. The processing procedure of this original UAE was first compared with conventional solvent extraction (CSE) using hexane as solvent. Moreover, the UAE optimal conditions for the subsequent comparison were optimized using response surface methodology (RSM) and ultra performance liquid chromatography--diode array detector--mass spectroscopy (UPLC-DAD-MS). The results showed that the UAE using sunflower as solvent has obtained its highest β-carotene yield (334.75 mg/l) in 20 min only, while CSE using hexane as solvent obtained a similar yield (321.35 mg/l) in 60 min. The green UAE performed under optimal extraction conditions (carrot to oil ratio of 2:10, ultrasonic intensity of 22.5 W cm(-2), temperature of 40 °C and sonication time of 20 min) gave the best yield of β-carotene. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. Postharvest Ultrasound-Assisted Freeze-Thaw Pretreatment Improves the Drying Efficiency, Physicochemical Properties, and Macamide Biosynthesis of Maca (Lepidium meyenii).

    Science.gov (United States)

    Chen, Jin-Jin; Gong, Peng-Fei; Liu, Yi-Lan; Liu, Bo-Yan; Eggert, Dawn; Guo, Yuan-Heng; Zhao, Ming-Xia; Zhao, Qing-Sheng; Zhao, Bing

    2018-04-01

    A novel technique of ultrasound-assisted freeze-thaw pretreatment (UFP) was developed to improve the drying efficiency of maca and bioactive amide synthesis in maca. The optimal UFP conditions are ultrasonic processing 90 min at 30 °C with 6 freeze-thaw cycles. Samples with freeze-thaw pretreatment (FP), ultrasound pretreatment (UP), and UFP were prepared for further comparative study. A no pretreatment (NP) sample was included as a control. The results showed that UFP improved the drying efficiency of maca slices, showing the highest effective moisture diffusivity (1.75 × 10 -9 m 2 /s). This result was further supported by low-field nuclear magnetic resonance (LF-NMR) analysis and scanning electron microscopy (SEM). The rehydration capacity and protein content of maca slices were improved by UFP. More importantly, contents of bioactive macamides and their biosynthetic precursors were increased in 2.5- and 10-fold, respectively. In conclusion, UFP is an efficient technique to improve drying efficiency, physicochemical properties, and bioactive macamides of maca, which can be applied in the industrial manufacture of maca products. © 2018 Institute of Food Technologists®.

  19. Optimization of Ultrasound-Assisted Extraction, HPLC and UHPLC-ESI-Q-TOF-MS/MS Analysis of Main Macamides and Macaenes from Maca (Cultivars of Lepidium meyenii Walp

    Directory of Open Access Journals (Sweden)

    Shu-Xiao Chen

    2017-12-01

    Full Text Available Ultrasound-assisted extraction (UAE, using petroleum ether as the solvent, was systematically applied to extract main macamides and macaenes from Maca hypocotyls. Extraction yield was related with four variables, including ratio of solution to solid, extraction temperature, extraction time, and extraction power. On the basis of response surface methodology (RSM, the optimal conditions were determined to be the ratio of solution to solid as 10:1 (mL/g, the extraction temperature of 40 °C, the extraction time of 30 min, and the extraction power of 200 W. Based on the optimal extraction method of UAE, the total contents of ten main macamides and two main macaenes of Maca cultivated in twenty different areas of Tibet were analyzed by HPLC and UHPLC-ESI-Q-TOF-MS/MS. This study indicated that UAE was able to effectively extract macamides alkaloids from Maca hypocotyls. Quantitative analysis showed that geographical origins, not ecotypes, played a more important role on the accumulation of active macamides in Maca.

  20. Optimization of Ultrasound-Assisted Extraction, HPLC and UHPLC-ESI-Q-TOF-MS/MS Analysis of Main Macamides and Macaenes from Maca (Cultivars of Lepidium meyenii Walp).

    Science.gov (United States)

    Chen, Shu-Xiao; Li, Ke-Ke; Pubu, Duoji; Jiang, Si-Ping; Chen, Bin; Chen, Li-Rong; Yang, Zhen; Ma, Chao; Gong, Xiao-Jie

    2017-12-10

    Ultrasound-assisted extraction (UAE), using petroleum ether as the solvent, was systematically applied to extract main macamides and macaenes from Maca hypocotyls. Extraction yield was related with four variables, including ratio of solution to solid, extraction temperature, extraction time, and extraction power. On the basis of response surface methodology (RSM), the optimal conditions were determined to be the ratio of solution to solid as 10:1 (mL/g), the extraction temperature of 40 °C, the extraction time of 30 min, and the extraction power of 200 W. Based on the optimal extraction method of UAE, the total contents of ten main macamides and two main macaenes of Maca cultivated in twenty different areas of Tibet were analyzed by HPLC and UHPLC-ESI-Q-TOF-MS/MS. This study indicated that UAE was able to effectively extract macamides alkaloids from Maca hypocotyls. Quantitative analysis showed that geographical origins, not ecotypes, played a more important role on the accumulation of active macamides in Maca.

  1. Ultrasound-assisted leaching of rare earths from the weathered crust elution-deposited ore using magnesium sulfate without ammonia-nitrogen pollution.

    Science.gov (United States)

    Yin, Shaohua; Pei, Jiannan; Jiang, Feng; Li, Shiwei; Peng, Jinhui; Zhang, Libo; Ju, Shaohua; Srinivasakannan, Chandrasekar

    2018-03-01

    The in situ leaching process of China's unique ion-adsorption rare earth ores has caused severe environmental damages due to the use of (NH 4 ) 2 SO 4 solution. This study reports that magnesium sulfate (MgSO 4 ) as a leaching agent would replace (NH 4 ) 2 SO 4 by ultrasonically assisted leaching to deal with the ammonia-nitrogen pollution problem and enhance leaching process. At leaching conditions of 3wt% MgSO 4 concentration, 3:1L/S ratio and 30min, the total rare earth leaching efficiency reaches 75.5%. Ultrasound-assisted leaching experiments show that the leaching efficiency of rare earths is substantially increased by introducing ultrasound, and nearly completely leached out after two stage leaching process. Thus, ultrasonic-assisted leaching process with MgSO 4 is not only effective but also environmentally friendly, and beneficial to leach rare earths at laboratory scale. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Comparisons between conventional, ultrasound-assisted and microwave-assisted methods for extraction of anthraquinones from Heterophyllaea pustulata Hook f. (Rubiaceae).

    Science.gov (United States)

    Barrera Vázquez, M F; Comini, L R; Martini, R E; Núñez Montoya, S C; Bottini, S; Cabrera, J L

    2014-03-01

    This work reports a comparative study about extraction methods used to obtain anthraquinones (AQs) from stems and leaves of Heterophyllae pustulata Hook (Rubiáceae). One of the conventional procedures used to extract these metabolites from a vegetable matrix is by successive Soxhlet extractions with solvents of increasing polarity: starting with hexane to eliminate chlorophylls and fatty components, following by benzene and finally ethyl acetate. However, this technique shows a low extraction yield of total AQs, and consumes large quantities of solvent and time. Ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) have been investigated as alternative methods to extract these compounds, using the same sequence of solvents. It was found that UAE increases the extraction yield of total AQs and reduces the time and amount of solvent used. Nevertheless, the combination UAE with benzene, plus MAE with ethyl acetate at a constant power of 900 W showed the best results. A higher yield of total AQs was obtained in less time and using the same amount of solvent that UAE. The optimal conditions for this latter procedure were UAE with benzene at 50 °C during 60 min, followed by MAE at 900 W during 15 min using ethyl acetate as extraction solvent. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Determination of personal care products and hormones in leachate and groundwater from Polish MSW landfills by ultrasound-assisted emulsification microextraction and GC-MS.

    Science.gov (United States)

    Kapelewska, Justyna; Kotowska, Urszula; Wiśniewska, Katarzyna

    2016-01-01

    Determination of the endocrine disrupting compounds (EDCs) in leachate and groundwater samples from the landfill sites is very important because of the proven harmful effects of these compounds on human and animal organisms. A method combining ultrasound-assisted emulsification microextraction (USAEME) and gas chromatography-mass spectrometry (GC-MS) was developed for simultaneous determination of seven personal care products (PCPs): methylparaben (MP), ethylparaben (EP), propylparaben (PP), buthylparaben (BP), benzophenone (BPh), 3-(4-methylbenzylidene)camphor (4-MBC), N,N-diethyltoluamide (DEET), and two hormones: estrone (E1) and β-estradiol (E2) in landfill leachate and groundwater samples. The limit of detection (LOD)/limit of quantification (LOQ) values in landfill leachate and groundwater samples were in the range of 0.003-0.083/0.009-0.277 μg L(-1) and 0.001-0.015/0.002-0.049 μg L(-1), respectively. Quantitative recoveries and satisfactory precision were obtained. All studied compounds were found in the landfill leachates from Polish municipal solid waste (MSW) landfills; the concentrations were between 0.66 and 202.42 μg L(-1). The concentration of pollutants in groundwater samples was generally below 0.1 μg L(-1).

  4. Simultaneous optimization of the ultrasound-assisted extraction for phenolic compounds content and antioxidant activity of Lycium ruthenicum Murr. fruit using response surface methodology.

    Science.gov (United States)

    Chen, Shasha; Zeng, Zhi; Hu, Na; Bai, Bo; Wang, Honglun; Suo, Yourui

    2018-03-01

    Lycium ruthenicum Murr. (LR) is a functional food that plays an important role in anti-oxidation due to its high level of phenolic compounds. This study aims to optimize ultrasound-assisted extraction (UAE) of phenolic compounds and antioxidant activities of obtained extracts from LR using response surface methodology (RSM). A four-factor-three-level Box-Behnken design (BBD) was employed to discuss the following extracting parameters: extraction time (X 1 ), ultrasonic power (X 2 ), solvent to sample ratio (X 3 ) and solvent concentration (X 4 ). The analysis of variance (ANOVA) results revealed that the solvent to sample ratio had a significant influence on all responses, while the extraction time had no statistically significant effect on phenolic compounds. The optimum values of the combination of phenolic compounds and antioxidant activities were obtained for X 1 =30min, X 2 =100W, X 3 =40mL/g, and X 4 =33% (v/v). Five phenolic acids, including chlorogenic acid, caffeic acid, syringic acid, p-coumaric acid and ferulic acid, were analyzed by HPLC. Our results indicated that optimization extraction is vital for the quantification of phenolic compounds and antioxidant activity in LR, which may be contributed to large-scale industrial applications and future pharmacological activities research. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Ultrasound assisted production of fatty acid methyl esters from transesterification of triglycerides with methanol in the presence of KOH catalyst: optimization, mechanism and kinetics.

    Science.gov (United States)

    Thanh, Le Tu; Okitsu, Kenji; Maeda, Yasuaki; Bandow, Hiroshi

    2014-03-01

    Ultrasound assisted transesterification of triglycerides (TG) with methanol in the presence of KOH catalyst was investigated, where the changes in the reactants and products (diglycerides (DG), monoglycerides (MG), fatty acid methyl esters (FAME) and glycerin (GL)) concentrations were discussed to understand the reaction mechanism and kinetics under ultrasound irradiation. The optimum reaction condition for the FAME production was the concentration of KOH 1.0 wt.%, molar ratio of TG to methanol of 1:6, and irradiation time of 25 min. The rate constants during the TG transesterification with methanol into GL and FAME were estimated by a curve fitting method with simulated curves to the obtained experimental results. The rate constants of [Formula: see text] were estimated to be 0.21, 0.008, 0.23, 0.005, 0.14 and 0.001 L mol(-1)min(-1), respectively. The rate determining step for the TG transesterification with methanol into GL and FAME was the reaction of MG with methanol into GL and FAME. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Ultrasound-assisted extraction technique for establishing selenium contents in breast cancer biopsies by Zeeman-electrothermal atomic absorption spectrometry using multi-injection

    International Nuclear Information System (INIS)

    Lavilla, I.; Mosquera, A.; Millos, J.; Cameselle, J.; Bendicho, C.

    2006-01-01

    A solid-liquid extraction method is developed to establish the contents of selenium in breast cancer biopsies. The method is based on the ultrasound-assisted extraction of selenium from pretreated biopsies prior to Se determination by atomic absorption spectrometry with longitudinal-Zeeman background correction. Fifty-one breast biopsies were collected from the Cies Hospital (Vigo, Spain), 32 of which correspond to tumor tissue and 19 to normal tissue (parenchyma). Difficulties arising from the samples analyzed, i.e. small samples mass (50-100 mg), extremely low Se contents and sample texture modification including tissue hardening due to formaldehyde preservation are addressed and overcome. High intensity sonication using a probe together with addition of hydrogen peroxide succeeded in completely extracting Se from biopsies. The multiple injection technique was useful to tackle the low Se contents present in some biopsies. The detection limit was 25 ng g -1 of Se and the precision, expressed as relative standard deviation, was less than 10%. Se contents ranged from 0.08 to 0.4 μg g -1 for parenchyma samples and from 0.09 to 0.8 μg g -1 for tumor samples. In general, Se levels in tumor biopsies were higher as compared with the adjacent normal tissue in 19 patients by a factor of up to 6. Analytical data confirmed Se accumulation in the breast tumors

  7. Sensitive Detection of Organophosphorus Pesticides in Medicinal Plants Using Ultrasound-Assisted Dispersive Liquid-Liquid Microextraction Combined with Sweeping Micellar Electrokinetic Chromatography.

    Science.gov (United States)

    Wei, Jin-Chao; Hu, Ji; Cao, Ji-Liang; Wan, Jian-Bo; He, Cheng-Wei; Hu, Yuan-Jia; Hu, Hao; Li, Peng

    2016-02-03

    A simple, rapid, and sensitive method using ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME) combined with sweeping micellar electrokinetic chromatography (sweeping-MEKC) has been developed for the determination of nine organophosphorus pesticides (chlorfenvinphos, parathion, quinalphos, fenitrothion, azinphos-ethyl, parathion-methyl, fensulfothion, methidathion, and paraoxon). The important parameters that affect the UA-DLLME and sweeping efficiency were investigated. Under the optimized conditions, the proposed method provided 779.0-6203.5-fold enrichment of the nine pesticides compared to the normal MEKC method. The limits of detection ranged from 0.002 to 0.008 mg kg(-1). The relative standard deviations of the peak area ranged from 1.2 to 6.5%, indicating the good repeatability of the method. Finally, the developed UA-DLLME-sweeping-MEKC method has been successfully applied to the analysis of the investigated pesticides in several medicinal plants, including Lycium chinense, Dioscorea opposite, Codonopsis pilosula, and Panax ginseng, indicating that this method is suitable for the determination of trace pesticide residues in real samples with complex matrices.

  8. Ultrasound-assisted extraction and solid-phase extraction for the simultaneous determination of five amide herbicides in fish samples by gas chromatography with electron capture detection.

    Science.gov (United States)

    Qu, Zhipeng; Bai, Xiuzhi; Zhang, Ting; Yang, Zhaoguang

    2017-03-01

    An efficient sample extraction and clean-up method was developed for simultaneous determination of five amide herbicides (alachlor, acetochlor, propisochlor, metazachlor, and butachlor) in fish samples. The protocol consisted of ultrasound-assisted solvent extraction and solid-phase extraction clean-up. In detail, aliquots of homogenized fish flesh were thoroughly mixed with 20 mL of n-hexane and then extracted with ultrasonication for 40 min. Each sample was centrifuged and the supernatant was collected for the subsequent clean-up. For the sample preparation, the above supernatant was processed with a C 18 column with 3 mL of dichloromethane/n-hexane (1:1, v/v) as the eluant. Then the samples were analyzed by gas chromatography with electron capture detection. The correlation coefficients of the five calibration curves were 0.9976-0.9998 (n = 3). The limits of detection (S/N = 3, n = 11) and limits of quantification (S/N = 10, n = 11) were 0.19-0.42 and 0.63-1.39 μg/kg, respectively. The recoveries of this method were 71.2-92.6% with good precision (<4.7% relative standard deviations, n = 6). The developed method was successfully applied to monitor the five amide herbicides in fish samples collected from different cities. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Trace determination of safranin O dye using ultrasound assisted dispersive solid-phase micro extraction: Artificial neural network-genetic algorithm and response surface methodology.

    Science.gov (United States)

    Dil, Ebrahim Alipanahpour; Ghaedi, Mehrorang; Asfaram, Arash; Mehrabi, Fatemeh; Bazrafshan, Ali Akbar; Ghaedi, Abdol Mohammad

    2016-11-01

    In this study, ultrasound assisted dispersive solid-phase micro extraction combined with spectrophotometry (USA-DSPME-UV) method based on activated carbon modified with Fe2O3 nanoparticles (Fe2O3-NPs-AC) was developed for pre-concentration and determination of safranin O (SO). It is known that the efficiency of USA-DSPME-UV method may be affected by pH, amount of adsorbent, ultrasound time and eluent volume and the extent and magnitude of their contribution on response (in term of main and interaction part) was studied by using central composite design (CCD) and artificial neural network-genetic algorithms (ANN-GA). Accordingly by adjustment of experimental conditions suggested by ANN-GA at pH 6.5, 1.1mg of adsorbent, 10min ultrasound and 150μL of eluent volume led to achievement of best operation performance like low LOD (6.3ngmL(-1)) and LOQ (17.5ngmL(-1)) in the range of 25-3500ngmL(-1). In following stage, the SO content in real water and wastewater samples with recoveries between 93.27-99.41% with RSD lower than 3% was successfully determined. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Simultaneous ultrasound-assisted water extraction and β-cyclodextrin encapsulation of polyphenols from Mangifera indica stem bark in counteracting TNFα-induced endothelial dysfunction.

    Science.gov (United States)

    Mura, Marzia; Palmieri, Daniela; Garella, Davide; Di Stilo, Antonella; Perego, Patrizia; Cravotto, Giancarlo; Palombo, Domenico

    2015-01-01

    This study proposes an alternative technique to prevent heat degradation induced by classic procedures of bioactive compound extraction, comparing classical maceration/decoction in hot water of polyphenols from Mango (Mangifera indica L.) (MI) with ultrasound-assisted extraction (UAE) in a water solution of β-cyclodextrin (β-CD) at room temperature and testing their biological activity on TNFα-induced endothelial dysfunction. Both extracts counteracted TNFα effects on EAhy926 cells, down-modulating interleukin-6, interleukin-8, cyclooxygenase-2 and intracellular adhesion molecule-1, while increasing endothelial nitric oxide synthase levels. β-CD extract showed higher efficacy in improving endothelial function. These effects were abolished after pre-treatment with the oestrogen receptor inhibitor ICI1182,780. Moreover, the β-CD extract induced Akt activation and completely abolished the TNFα-induced p38MAPK phosphorylation. UAE and β-CD encapsulation provide an efficient extraction protocol that increases polyphenol bioavailability. Polyphenols from MI play a protective role on endothelial cells and may be further considered as oestrogen-like molecules with vascular protective properties.

  11. Extraction of Natural Antioxidants from the Thelephora ganbajun Mushroom by an Ultrasound-Assisted Extraction Technique and Evaluation of Antiproliferative Activity of the Extract against Human Cancer Cells.

    Science.gov (United States)

    Xu, Dong-Ping; Zheng, Jie; Zhou, Yue; Li, Ya; Li, Sha; Li, Hua-Bin

    2016-10-01

    The Thelephora ganbajun mushroom has been found to be a potential rich source of natural antioxidants. In this study, an ultrasound-assisted extraction (UAE) technique together with GRAS (generally recognized as safe) solvents (ethanol and water) was used to maximize the extraction of antioxidants from Thelephora ganbajun . Five extraction parameters (ethanol concentration, solvent to solid ratio, extraction time, temperature and ultrasound power) were investigated by single-factor experiments, and then a central composite rotatable design was employed to study interaction of three key extraction parameters. The optimum conditions were as follows: 57.38% ethanol, 70.15 mL/g solvent to solid ratio, 10.58 min extraction time, 40 °C extraction temperature and 500 W ultrasound power. Under the optimum conditions, the antioxidant activity obtained was 346.98 ± 12.19 µmol Trolox/g DW, in accordance with the predicted value of 344.67 µmol Trolox/g DW. Comparison of UAE with conventional maceration and Soxhlet extraction, the UAE method showed stronger extract efficiency in a shorter extraction time. These results showed that UAE was an effective technique to extract antioxidants from Thelephora ganbajun . Furthermore, the extracts obtained under the optimized conditions exhibited antiproliferative activities toward human lung (A549), breast (MCF-7), liver (HepG2) and colon (HT-29) cancer cells, especially for liver and lung cancer cells. In addition, rutin, 2-hydrocinnamic acid and epicatechin were identified in the extract, which might contribute to antioxidant and antiproliferative activities.

  12. A Method Based on Ultrasound-assisted Solidification of Floating Drop Microextraction Technique for the Spectrophotometric Determination of Curcumin in Turmeric Powder

    Directory of Open Access Journals (Sweden)

    Abbas Afkhami

    2017-06-01

    Full Text Available A method based on the ultrasound-assisted solidification of floating drop microextraction technique was developed for the spectrophotometric and spectrofluorimetric determination of curcumin in turmeric powder. In this work a small volume of an organic solvent was floated on the surface of an aqueous solution. After sonication the organic solvent is solidified and separated. The effect of extraction parameters such as type and the volume of organic solvent, temperature, salt addition and exposure time, on the extraction recovery was investigated and optimized. Finally, the method droplet was used for the determination of analyte. Under the optimum extraction conditions, a linear range of 0.006–30 μg mL-1 and a relative standard deviation (RSD of 2.72% for curcumin wasachieved. Limits of detection of 7 and 2 ng mL-1 curcumin was obtained for the spectrophotometric and spectrofluometric methods, respectively. The obtained results show that the application of this method can be successful for the analysis of curcumin in turmeric powder samples.

  13. Ultrasound-assisted dispersive solid phase extraction of cadmium(II) and lead(II) using a hybrid nanoadsorbent composed of graphene and the zeolite clinoptilolite

    International Nuclear Information System (INIS)

    Ghazaghi, Mehri; Mousavi, Hassan Zavvar; Shirkhanloo, Hamid; Rashidi, Ali Morad

    2015-01-01

    We describe a hybrid nanoadsorbent prepared by depositing graphene on the zeolite clinoptilolite by chemical vapor deposition. The resulting sorbent is well suited for the preconcentration of lead(II) and cadmium(II) by ultrasound-assisted dispersive micro solid–phase extraction. An extraction unit has been designed and manufactured that facilitates handling of small sample volumes. The effects of sample pH, amount of sorbent, concentration and volume of elution and time of ultrasonic bath were investigated. The nanoadsorbent was characterized by scanning electron microscopy, X-ray diffraction and energy dispersive X-ray microanalysis, all of which revealed the high surface area of the graphene sheets on the clinoptilolite. The extraction recoveries when using the new nanoadsorbent are 97 % (as opposed to a mere 10 % in case of clinoptilolite only). It is assumed that the graphene sheets located around the porous structure of clinoptilolite are acting as a barrier against macromolecules potentially existing in the sample matrices. The method was applied to the determination of lead and cadmium in water and human serum samples by electrothermal atomic absorption spectrometry. The detection limits were as low as 70 and 4 ng L −1 for Pb(II) and Cd(II), respectively. The accuracy of the method was underpinned by correct analysis of a standard reference material (SRM: 203105 Seronorm Trace Elements Serum L-2). (author)

  14. Influence of High Shear Dispersion on the Production of Cellulose Nanofibers by Ultrasound-Assisted TEMPO-Oxidation of Kraft Pulp

    Directory of Open Access Journals (Sweden)

    Claude Daneault

    2012-09-01

    Full Text Available Cellulose nanofibers can be produced using a combination of TEMPO, sodium bromide (NaBr and sodium hypochlorite, and mechanical dispersion. Recently, this process has been the subject of intensive investigation. However, studies on the aspects of mechanical treatment of this process remain marginal. The main objective of this study is to evaluate the high shear dispersion parameters (e.g., consistency, stator-rotor gap, recirculation rate and pH and determine their influences on nanocellulose production using ultrasound-assisted TEMPO-oxidation of Kraft pulp. All nanofiber gels produced in this study exhibited rheological behaviors known as shear thinning. From all the dispersion parameters, the following conditions were identified as optimal: 0.042 mm stator-rotor gap, 200 mL/min recycle rate, dispersion pH of 7 and a feed consistency of 2%. High quality cellulose gel could be produced under these conditions. This finding is surely of great interest for the pulp and paper industry.

  15. Effects of Ultrasound Assisted Extraction in Conjugation with Aid of Actinidin on the Molecular and Physicochemical Properties of Bovine Hide Gelatin

    Directory of Open Access Journals (Sweden)

    Tanbir Ahmad

    2018-03-01

    Full Text Available Actinidin was used to pretreat the bovine hide and ultrasonic wave (53 kHz and 500 W was used for the time durations of 2, 4 and 6 h at 60 °C to extract gelatin samples (UA2, UA4 and UA6, respectively. Control (UAC gelatin was extracted using ultrasound for 6 h at 60 °C without enzyme pretreatment. There was significant (p < 0.05 increase in gelatin yield as the time duration of ultrasound treatment increased with UA6 giving the highest yield of 19.65%. Gel strength and viscosity of UAC and UA6 extracted gelatin samples were 627.53 and 502.16 g and 16.33 and 15.60 mPa.s, respectively. Longer duration of ultrasound treatment increased amino acids content of the extracted gelatin and UAC exhibited the highest content of amino acids. Progressive degradation of polypeptide chains was observed in the protein pattern of the extracted gelatin as the time duration of ultrasound extraction increased. Fourier transform infrared (FTIR spectroscopy depicted loss of molecular order and degradation in UA6. Scanning electron microscopy (SEM revealed protein aggregation and network formation in the gelatin samples with increasing time of ultrasound treatment. The study indicated that ultrasound assisted gelatin extraction using actinidin exhibited high yield with good quality gelatin.

  16. Double spike isotope dilution GC-ICP-MS for evaluation of mercury species transformation in real fish samples using ultrasound-assisted extraction.

    Science.gov (United States)

    Esteban-Fernández, Diego; Mirat, Manuela; de la Hinojosa, M Ignacia Martín; Alonso, J Ignacio García

    2012-08-29

    Sample preparation continues being a key factor to obtain fast and reliable quantification of Hg species. Assisted procedures enhance the efficiency and reduce the extraction time; however, collateral species transformations have been observed. Moreover, differential interconversions have been observed even between similar matrixes, which introduce an important uncertainty for real sample analysis. Trying to minimize Hg species transformations, we have tested a soft ultrasound-assisted extraction procedure. Species quantification and transformations have been evaluated using double spike isotope dilution analysis (IDA) together with gas chromatography inductively coupled plasma mass spectrometry (GC-ICP-MS) for a CRM material (Tort-2) and shark and swordfish muscle samples. Optimum extraction solution and sonication time led to quantitative extraction and accurate determination of MeHg and IHg in a short time, although different behaviors regarding species preservation were observed depending on the sample. Negligible species transformations were observed in the analysis of the CRM, while a small but significant demethylation factor was observed in the case of real samples. In comparison with other extraction procedures, species transformations became smaller, and fewer differences between fish species were found. Similar results were obtained for fresh and lyophilized samples of both fish samples, which permit one to analyze the fresh sample directly and save time in the sample preparation step. The high grade of species preservation and the affordability of the extraction procedure allow one to obtain accurate determinations even for routine laboratories using quantification techniques, which do not estimate species transformations.

  17. Optimization of Ultrasound-Assisted Extraction of Crude Oil from Winter Melon (Benincasa hispida Seed Using Response Surface Methodology and Evaluation of Its Antioxidant Activity, Total Phenolic Content and Fatty Acid Composition

    Directory of Open Access Journals (Sweden)

    Md. Zaidul Islam Sarker

    2012-10-01

    Full Text Available In the present study, ultrasound-assisted extraction of crude oil from winter melon seeds was investigated through response surface methodology (RSM. Process variables were power level (25–75%, temperature (45–55 °C and sonication time (20–40 min. It was found that all process variables have significant (p < 0.05 effects on the response variable. A central composite design (CCD was used to determine the optimum process conditions. Optimal conditions were identified as 65% power level, 52 °C temperature and 36 min sonication time for maximum crude yield (108.62 mg-extract/g-dried matter. The antioxidant activity, total phenolic content and fatty acid composition of extract obtained under optimized conditions were determined and compared with those of oil obtained by the Soxhlet method. It was found that crude extract yield (CEY of ultrasound-assisted extraction was lower than that of the Soxhlet method, whereas antioxidant activity and total phenolic content of the extract obtained by ultrasound-assisted extraction were clearly higher than those of the Soxhlet extract. Furthermore, both extracts were rich in unsaturated fatty acids. The major fatty acids of the both extracts were linoleic acid and oleic acid.

  18. Ionic liquid and nanoparticle hybrid systems: Emerging applications.

    Science.gov (United States)

    He, Zhiqi; Alexandridis, Paschalis

    2017-06-01

    Having novel electronic and optical properties that emanate from their nano-scale dimensions, nanoparticles are central to numerous applications. Ionic liquids can confer to nanoparticle chemical protection and physicochemical property enhancement through intermolecular interactions and can consequently improve the stability and reusability of nanoparticle for various operations. With an aim to combine the novel properties of nanoparticles and ionic liquids, different structures have been generated, based on a balance of several intermolecular interactions. Such ionic liquid and nanoparticle hybrids are showing great potential in diverse applications. In this review, we first introduce various types of ionic liquid and nanoparticle hybrids, including nanoparticle colloidal dispersions in ionic liquids, ionic liquid-grafted nanoparticles, and nanoparticle-stabilized ionic liquid-based emulsions. Such hybrid materials exhibit interesting synergisms. We then highlight representative applications of ionic liquid and nanoparticle hybrids in the catalysis, electrochemistry and separations fields. Such hybrids can attain better stability and higher efficiency under a broad range of conditions. Novel and enhanced performance can be achieved in these applications by combining desired properties of ionic liquids and of nanoparticles within an appropriate hybrid nanostructure. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Effect of irradiation power and time on ultrasound assisted co-precipitation of nanostructured CuO–ZnO–Al2O3 over HZSM-5 used for direct conversion of syngas to DME as a green fuel

    International Nuclear Information System (INIS)

    Allahyari, Somaiyeh; Haghighi, Mohammad; Ebadi, Amanollah; Hosseinzadeh, Shahin

    2014-01-01

    Graphical abstract: Nanostructured CuO–ZnO–Al 2 O 3 /HZSM-5 catalyst has been prepared by an ultrasound-assisted co-precipitation hybrid method. Effect of power and irradiation time have been studied by changing the time (30–45–60 min) and power of sonication (50–100–150 W) during the synthesis which lead to different physiochemical properties of the catalyst. The XRD, FESEM, EDX, FTIR and BET analyses exhibited smaller particles with higher surface area and less population of particle aggregates at longer and highly irradiated catalysts. Study on the performance of investigated catalysts in direct synthesis of DME from syngas showed ultrasound-assisted co-precipitated synthesized catalysts have superior reactivity and stability compared with non-sonicated catalyst. Among sonicated catalysts, with increasing power and time of irradiation, the catalyst represents higher activity and DME selectivity. - Highlights: • Synthesis of CuO–ZnO–Al 2 O 3 /HZSM-5 by ultrasound assisted co-precipitation method. • Significant changes in morphology and surface area after ultrasound irradiations. • Smaller dispersed particle aggregates in longer and more intense irradiated catalysts. • Improvement in reactivity and stability of the longer and more intense ultrasound irradiated CZAZ catalyst. - Abstract: Nanostructured CuO–ZnO–Al 2 O 3 /HZSM-5 catalyst has been prepared by an ultrasound-assisted co-precipitation hybrid method. The effect of irradiation power and irradiation time have been studied by changing time (30, 45, 60 min) and power of the sonication (50, 100, 150 W) during the synthesis which led to different physiochemical properties of the nanocatalyst. The XRD, FESEM, EDX, FTIR and BET analyses exhibited smaller particles with higher surface area and less population of particle aggregates at longer and highly irradiated nanocatalysts. The nanocatalyst irradiated at 150 W for 60 min (the longest irradiation time and the most intense power

  20. Ultrasound assisted dispersive liquid-liquid microextraction coupled with high performance liquid chromatography designated for bioavailability studies of felodipine combinations in rat plasma.

    Science.gov (United States)

    Ahmed, Sameh; Atia, Noha N; Bakr Ali, Marwa Fathy

    2017-03-01

    Felodipine (FLD), a calcium channel antagonist, is commonly prescribed for the treatment of hypertension either with Metoprolol (MET) or Ramipril (RAM) in two different drug combinations. FLD has high plasma protein binding ability affecting its extraction recoveries from plasma samples. Hence, a specific ultrasound assisted dispersive liquid-liquid microextraction (UA-DLLME) method coupled with HPLC using photodiode array detector was developed and validated for the simultaneous determination of FLD, MET and RAM in rat plasma after oral administration of these combinations. The factors affecting UA-DLLME were carefully optimized. In this study, UA-DLLME method could provide simple and efficient plasma extraction procedures with superior recovery results. Under optimum condition, all target drugs were separated within 13min. The validation procedures was carried out in agreement with US-FDA guidelines and shown to be suitable for anticipated purposes. Linear calibration ranges were obtained in the range 0.05-2.0μgmL -1 for FLD and MET and 0.1-2.0μgmL -1 for RAM with detection limits of 0.013-0.031μgmL -1 for all the studied drug combinations. The%RSD for inter-day and intra-day precisions was in range of 0.63-3.85% and the accuracy results were in the range of 92.13-100.5%. The validated UA-DLLME-HPLC method was successfully applied for the bioavailability studies of FLD, MET and RAM. The pharmacokinetic parameters were calculated for all the investigated drugs in rats after single-dose administrations of two different drug combinations. Although FLD was bioequivalent in the two formulations, a small increase in plasma levels of MET and RAM was found in the presence of FLD. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Ultrasound assisted combined molecularly imprinted polymer for selective extraction of nicotinamide in human urine and milk samples: Spectrophotometric determination and optimization study.

    Science.gov (United States)

    Asfaram, Arash; Ghaedi, Mehrorang; Dashtian, Kheibar

    2017-01-01

    Ultrasound-assisted dispersive solid phase microextraction followed by UV-vis spectrophotometer (UA-DSPME-UV-vis) was designed for extraction and preconcentration of nicotinamide (vitamin B 3 ) by HKUST-1 metal organic framework (MOF) based molecularly imprinted polymer (MIP). This new material was characterized by FTIR and FE-SEM techniques. The preliminary Plackett-Burman design was used for screening and subsequently the central composite design justifies significant terms and possible construction of mathematical equation which give the individual and cooperative contribution of variables like HKUST-1-MOF-NA-MIP mass, sonication time, temperature, eluent volume, pH and vortex time. Accordingly the optimum condition was set as: 2.0mg HKUST-1-MOF-NA-MIP, 200μL eluent and 5.0min sonication time in center points other variables were determined as the best conditions to reach the maximum recovery of the analyte. The UA-DSPME-UV-vis method performances like excellent linearity (LR), limits of detection (LOD), limits of quantification of 10-5000μgL -1 with R 2 of 0.99, LOD (1.96ngmL -1 ), LOQ (6.53μgL -1 ), respectively show successful and accurate applicability of the present method for monitoring analytes with within- and between-day precision of 0.96-3.38%. The average absolute recoveries of the nicotinamide extracted from the urine, milk and water samples were 95.85-101.27%. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. [Ultrasound-assisted approach to blocking the intercostal nerves in the mid-axillary line for non-reconstructive breast and axilla surgery].

    Science.gov (United States)

    Diéguez García, P; Fajardo Pérez, M; López Álvarez, S; Alfaro de la Torre, P; Pensado Castiñeiras, A P

    2013-01-01

    Several nerve blocks have recently been used for pain treatment in breast surgery. The main objective of our study was to determine the efficacy and safety of ultrasound-assisted blocking of the anterior and lateral cutaneous branches of the intercostal nerves in the mid-axillary line for non-reconstructive breast and axilla surgery. A prospective observational study was conducted on 30 patients scheduled for non-reconstructive breast and axilla surgery. An intercostal branches block was performed in the mid-axillary line with 0,5% levobupivacaine (3ml in each intercostal space). Clinical efficacy was assessed by standard intraoperative hemodynamic response to surgical stimulus and the need for opioids, and in the postoperative period, by assessing pain intensity as a verbal numerical scale and the need for rescue treatment. We also evaluated the quality of sleep the first night after surgery, any adverse events that occurred, and the satisfaction of patients and surgeons with the anesthetic technique. The intercostal branches block in the mid-axillary line was effective in most cases, with only 2 patients requiring intraoperative opioids, and in one case analgesic rescue was necessary in the postoperative period. The duration of postoperative analgesia was 19±4h. There were no notable adverse events or complications. The satisfaction with the chosen technique was assessed as "very good" in all patients, and by 97% of the surgeons. Intercostal branches block in the mid-axillary line provides adequate intraoperative and postoperative analgesia for non-reconstructive breast and axilla surgery. It is a simple, reproducible technique in most patients of this study, with an easy to understand ultrasound anatomy, in which adequate analgesia could be provided through a single puncture, and may be an alternative to neuroaxial blocks. Copyright © 2013 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Published by Elsevier España. All rights

  3. A Retrospective Comparison of Ultrasound-Assisted Catheter-Directed Thrombolysis and Catheter-Directed Thrombolysis Alone for Treatment of Proximal Deep Vein Thrombosis

    Energy Technology Data Exchange (ETDEWEB)

    Tichelaar, Vladimir Y. I. G., E-mail: ynse.i.tichelaar@uit.no; Brodin, Ellen E.; Vik, Anders; Isaksen, Trond [UiT – The Arctic University of Norway, K. G. Jebsen – Thrombosis Research and Expertise Centre (TREC), Department of Clinical Medicine (Norway); Skjeldestad, Finn Egil [UiT – The Arctic University of Norway, Research Group Epidemiology of Chronic Diseases, Department of Community Medicine (Norway); Kumar, Satish; Trasti, Nora C.; Singh, Kulbir [University Hospital of North Norway, Department of Radiology (Norway); Hansen, John-Bjarne [UiT – The Arctic University of Norway, K. G. Jebsen – Thrombosis Research and Expertise Centre (TREC), Department of Clinical Medicine (Norway)

    2016-08-15

    BackgroundRecent studies have suggested that catheter-directed thrombolysis (CDT) reduces development of post-thrombotic syndrome (PTS). Ultrasound-assisted CDT (USCDT) might enhance the efficiency of thrombolysis. We aimed to compare USCDT with CDT on efficacy, safety, development of PTS, and quality of life after long-term follow-up.MethodsWe describe a retrospective case series of 94 consecutive patients admitted with iliofemoral or more proximal deep vein thrombosis (DVT) to the University Hospital from 2002 to 2011, treated either with CDT or USCDT. Scheduled follow-up visits took place between April 2013 and January 2014. Venography measured the degree of residual luminal obstruction of the affected veins. Each patient completed the Short Form 36-item health survey assessment and the Venous Insufficiency Epidemiological and Economic Study-Quality of Life/Symptoms questionnaires. PTS was assessed using the Villalta scale.ResultsRisk factors of DVT were equally distributed between groups. In the USCDT group, we observed a significant decline in the duration of thrombolytic treatment (<48 h: 27 vs. 10 %), shortened hospital stay (median 6.0 days (IQR 5.0–9.0) vs. 8.0 (IQR 5.8–12.0)), and less implantation of (intravenous) stents (30 vs. 55 %). There was no difference in patency (76 vs. 79 % fully patent), prevalence of PTS (52 vs. 55 %), or quality of life between groups after long-term follow-up (median 65 months, range: 15–141).ConclusionsIn this observational study, USCDT was associated with shortened treatment duration, shorter hospital stay, and less intravenous stenting, compared to CDT alone without affecting the long-term prevalence of PTS or quality of life.

  4. The choice of ultrasound assisted extraction coupled with spectrophotometric for rapid determination of gallic acid in water samples: Central composite design for optimization of process variables.

    Science.gov (United States)

    Pooralhossini, Jaleh; Ghaedi, Mehrorang; Zanjanchi, Mohammad Ali; Asfaram, Arash

    2017-01-01

    A sensitive procedure namely ultrasound-assisted (UA) coupled dispersive nano solid-phase microextraction spectrophotometry (DNSPME-UV-Vis) was designed for preconcentration and subsequent determination of gallic acid (GA) from water samples, while the detailed of composition and morphology and also purity and structure of this new sorbent was identified by techniques like field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and Energy-dispersive X-ray spectroscopy (EDX) techniques. Among conventional parameters viz. pH, amount of sorbent, sonication time and volume of elution solvent based on Response Surface Methodology (RSM) and central composite design according to statistics based contour the best operational conditions was set at pH of 2.0; 1.5mg sorbent, 4.0min sonication and 150μL ethanol. Under these pre-qualified conditions the method has linear response over wide concentration range of 15-6000ngmL -1 with a correlation coefficient of 0.9996. The good figure of merits like acceptable LOD (S/N=3) and LOQ (S/N=10) with numerical value of 2.923 and 9.744ngmL -1 , respectively and relative recovery between 95.54 and 100.02% show the applicability and efficiency of this method for real samples analysis with RSDs below 6.0%. Finally the method with good performance were used for monitoring under study analyte in various real samples like tap, river and mineral waters. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Determination of fragrance allergens in indoor air by active sampling followed by ultrasound-assisted solvent extraction and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Lamas, J Pablo; Sanchez-Prado, Lucia; Garcia-Jares, Carmen; Llompart, Maria

    2010-03-19

    Fragrances are ubiquitous pollutants in the environment, present in the most of household products, air fresheners, insecticides and cosmetics. Commercial perfumes may contain hundreds of individual fragrance chemicals. In addition to the widespread use and exposure to fragranced products, many of the raw fragrance materials have limited available health and safety data. Because of their nature as artificial fragrances, inhalation should be considered as an important exposure pathway, especially in indoor environments. In this work, a very simple, fast, and sensitive methodology for the analysis of 24 fragrance allergens in indoor air is presented. Considered compounds include those regulated by the EU Directive, excluding limonene; methyl eugenol was also included due to its toxicity. The proposed methodology is based on the use of a very low amount of adsorbent to retain the target compounds, and the rapid ultrasound-assisted solvent extraction (UAE) using a very low volume of solvent which avoids further extract concentration. Quantification was performed by gas chromatography coupled to mass spectrometry (GC-MS). The influence of main factors involved in the UAE step (type of adsorbent and solvent, solvent volume and extraction time) was studied using an experimental design approach to account for possible factor interactions. Using the optimized procedure, 0.2 m(-3) air are sampled, analytes are retained on 25 mg Florisil, from which they are extracted by UAE (5 min) with 2 mL ethyl acetate. Linearity was demonstrated in a wide concentration range. Efficiency of the total sampling-extraction process was studied at several concentration levels (1, 5 and 125 microg m(-3)), obtaining quantitative recoveries, and good precision (RSD<10%). Method detection limits were < or =0.6 microg m(-3). Finally, the proposed method was applied to real samples collected in indoor environments in which several of the target compounds were determined. Copyright 2010 Elsevier B

  6. Evaluation, prediction and optimization the ultrasound-assisted extraction method using response surface methodology: antioxidant and biological properties of Stachys parviflora L.

    Science.gov (United States)

    Bashi, Davoud Salar; Dowom, Samaneh Attaran; Bazzaz, Bibi Sedigheh Fazly; Khanzadeh, Farhad; Soheili, Vahid; Mohammadpour, Ali

    2016-05-01

    To optimize the extraction method using response surface methodology, extract the phenolic compounds, and identify the antioxidant and biological properties of Stachys parviflora L. extracts. Maceration and ultrasound-assisted extraction (UAE) (4, 7, 10 min treatment time, 40, 70, 100 % high-intensity and 60, 80, 100 % (v v-1) methanol purity) were applied to obtain the extracts. SEM was conducted to provide the microstructure of the extracted plant. MICs (colorimetric assay), MFCs (colony diameter), total phenolic content, total flavonoid content, radical scavenging capacity and extraction efficiency were determined. HPLC analysis was applied to measure the existent phenolic compounds. A quadratic model (4 min treatment time, 74.5 % high-intensity and 74.2 % solvent purity) was suggested as the best (TPC: 20.89 mg GAE g-1 d.m., TFC: 6.22 mg QEs g-1 d.m., DPPH IC50: 21.86 µg ml-1 and EE: 113.65 mg g-1 d.m.) UAE extraction model. The optimized UAE extract was generally more effective against Gram-positive microorganisms (MIC: 10-20; MBC: 10-40 (mg ml-1)) than Gram-negative ones (MIC: 40; MBC: >40 (mg ml-1)). Moreover, it (MGI: 2.32-100 %) revealed more anti-mold activity than maceration (MGI: <28.77 %). Explosive disruption of the cell walls, therefore, enhanced extraction yield by acoustic cavitation, was elucidated using SEM. Caffeic acid, tannic acid, quercetin, trans ferulic acid and rosmarinic acid were determined as the phenolic compounds in the optimized extract. RSM optimization was successfully applied for UAE from S. parviflora. The considerable antioxidant and biological properties were attributed to the phenolic compounds.

  7. Evaluation, prediction and optimization the ultrasound-assisted extraction method using response surface methodology: antioxidant and biological properties of Stachys parviflora L.

    Directory of Open Access Journals (Sweden)

    Davoud Salarbashi

    2016-05-01

    Full Text Available Objective(s:To optimize the extraction method using response surface methodology, extract the phenolic compounds, and identify the antioxidant and biological properties of Stachys parviflora L.  extracts. Materials and Methods: Maceration and ultrasound-assisted extraction (UAE (4, 7, 10 min treatment time, 40, 70, 100 % high-intensity and 60, 80, 100 % (v v-1 methanol purity were applied to obtain the extracts. SEM was conducted to provide the microstructure of the extracted plant. MICs (colorimetric assay, MFCs (colony diameter, total phenolic content, total flavonoid content, radical scavenging capacity and extraction efficiency were determined. HPLC analysis was applied to measure the existent phenolic compounds. Results: A quadratic model (4 min treatment time, 74.5 % high-intensity and 74.2 % solvent purity was suggested as the best (TPC: 20.89 mg GAE g-1 d.m., TFC: 6.22 mg QEs g-1 d.m., DPPH IC50: 21.86 µg ml-1 and EE: 113.65 mg g-1 d.m. UAE extraction model. The optimized UAE extract was generally more effective against Gram-positive microorganisms (MIC: 10-20; MBC: 10-40 (mg ml-1 than Gram-negative ones (MIC: 40; MBC: >40 (mg ml-1. Moreover, it (MGI: 2.32-100 % revealed more anti-mold activity than maceration (MGI: Conclusion: RSM optimization was successfully applied for UAE from S. parviflora. The considerable antioxidant and biological properties were attributed to the phenolic compounds.

  8. Ultrasound assisted extraction of Maxilon Red GRL dye from water samples using cobalt ferrite nanoparticles loaded on activated carbon as sorbent: Optimization and modeling.

    Science.gov (United States)

    Mehrabi, Fatemeh; Vafaei, Azam; Ghaedi, Mehrorang; Ghaedi, Abdol Mohammad; Alipanahpour Dil, Ebrahim; Asfaram, Arash

    2017-09-01

    In this research, a selective, simple and rapid ultrasound assisted dispersive solid-phase micro-microextraction (UA-DSPME) was developed using cobalt ferrite nanoparticles loaded on activated carbon (CoFe 2 O 4 -NPs-AC) as an efficient sorbent for the preconcentration and determination of Maxilon Red GRL (MR-GRL) dye. The properties of sorbent are characterized by X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), Vibrating sample magnetometers (VSM), Fourier transform infrared spectroscopy (FTIR), Particle size distribution (PSD) and Scanning Electron Microscope (SEM) techniques. The factors affecting on the determination of MR-GRL dye were investigated and optimized by central composite design (CCD) and artificial neural networks based on genetic algorithm (ANN-GA). CCD and ANN-GA were used for optimization. Using ANN-GA, optimum conditions were set at 6.70, 1.2mg, 5.5min and 174μL for pH, sorbent amount, sonication time and volume of eluent, respectively. Under the optimized conditions obtained from ANN-GA, the method exhibited a linear dynamic range of 30-3000ngmL -1 with a detection limit of 5.70ngmL -1 . The preconcentration factor and enrichment factor were 57.47 and 93.54, respectively with relative standard deviations (RSDs) less than 4.0% (N=6). The interference effect of some ions and dyes was also investigated and the results show a good selectivity for this method. Finally, the method was successfully applied to the preconcentration and determination of Maxilon Red GRL in water and wastewater samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Ultrasound-assisted extraction of azadirachtin from dried entire fruits of Azadirachta indica A. Juss. (Meliaceae) and its determination by a validated HPLC-PDA method.

    Science.gov (United States)

    de Paula, Joelma Abadia Marciano; Brito, Lucas Ferreira; Caetano, Karen Lorena Ferreira Neves; de Morais Rodrigues, Mariana Cristina; Borges, Leonardo Luiz; da Conceição, Edemilson Cardoso

    2016-01-01

    Azadirachta indica A. Juss., also known as neem, is a Meliaceae family tree from India. It is globally known for the insecticidal properties of its limonoid tetranortriterpenoid derivatives, such as azadirachtin. This work aimed to optimize the azadirachtin ultrasound-assisted extraction (UAE) and validate the HPLC-PDA analytical method for the measurement of this marker in neem dried fruit extracts. Box-Behnken design and response surface methodology (RSM) were used to investigate the effect of process variables on the UAE. Three independent variables, including ethanol concentration (%, w/w), temperature (°C), and material-to-solvent ratio (gmL(-1)), were studied. The azadirachtin content (µgmL(-1)), i.e., dependent variable, was quantified by the HPLC-PDA analytical method. Isocratic reversed-phase chromatography was performed using acetonitrile/water (40:60), a flow of 1.0mLmin(-1), detection at 214nm, and C18 column (250×4.6mm(2), 5µm). The primary validation parameters were determined according to ICH guidelines and Brazilian legislation. The results demonstrated that the optimal UAE condition was obtained with ethanol concentration range of 75-80% (w/w), temperature of 30°C, and material-to-solvent ratio of 0.55gmL(-1). The HPLC-PDA analytical method proved to be simple, selective, linear, precise, accurate and robust. The experimental values of azadirachtin content under optimal UAE conditions were in good agreement with the RSM predicted values and were superior to the azadirachtin content of percolated extract. Such findings suggest that UAE is a more efficient extractive process in addition to being simple, fast, and inexpensive. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. A convenient ultrasound-assisted saponification for the simultaneous determination of vitamin E isomers in vegetable oil by HPLC with fluorescence detection.

    Science.gov (United States)

    Yang, Yi; Lu, Dan; Yin, Shuo; Yang, Danni; Chen, Yaling; Li, Yongxin; Sun, Chengjun

    2018-04-01

    An efficient ultrasound-assisted saponification was developed for simultaneous determination of vitamin E isomers in vegetable oil by high-performance liquid chromatography with fluorescence detection. The samples were saponified ultrasonically with potassium hydroxide solution for only 7 min, then the analytes were extracted with ether. Vitamin E isomers were separated on a C 18 column at 25°C with a mobile phase of methanol/acetonitrile (81:19, v/v) at a flow rate of 0.8 mL/min. Fluorescence detection was operated at 290 nm of excitation wavelength and 327 nm of emission wavelength. Under the optimized conditions, good linearities over the range of 0.001-8.00 μg/mL (r > 0.999) were obtained. Mean recoveries of the method were 88.0-106%, with intra- and interday RSDs less than 11.8 and 12.8%, respectively. The detection limits and quantification limits of the method were 0.30-1.8 and 1.0-6.1 μg/kg, respectively. The recoveries of this method were much higher than that of the quick, easy, cheap, effective, rugged, and safe method and direct dilution method, but were similar to those of hot saponification. This proposed method provides reliable, simple, and rapid quantification of vitamin E isomers in vegetable oils. Five kinds of vegetable oils were analyzed, the quantification results were within the ranges reported by other authors. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Extraction of Natural Antioxidants from the Thelephora ganbajun Mushroom by an Ultrasound-Assisted Extraction Technique and Evaluation of Antiproliferative Activity of the Extract against Human Cancer Cells

    Directory of Open Access Journals (Sweden)

    Dong-Ping Xu

    2016-10-01

    Full Text Available The Thelephora ganbajun mushroom has been found to be a potential rich source of natural antioxidants. In this study, an ultrasound-assisted extraction (UAE technique together with GRAS (generally recognized as safe solvents (ethanol and water was used to maximize the extraction of antioxidants from Thelephora ganbajun. Five extraction parameters (ethanol concentration, solvent to solid ratio, extraction time, temperature and ultrasound power were investigated by single-factor experiments, and then a central composite rotatable design was employed to study interaction of three key extraction parameters. The optimum conditions were as follows: 57.38% ethanol, 70.15 mL/g solvent to solid ratio, 10.58 min extraction time, 40 °C extraction temperature and 500 W ultrasound power. Under the optimum conditions, the antioxidant activity obtained was 346.98 ± 12.19 µmol Trolox/g DW, in accordance with the predicted value of 344.67 µmol Trolox/g DW. Comparison of UAE with conventional maceration and Soxhlet extraction, the UAE method showed stronger extract efficiency in a shorter extraction time. These results showed that UAE was an effective technique to extract antioxidants from Thelephora ganbajun. Furthermore, the extracts obtained under the optimized conditions exhibited antiproliferative activities toward human lung (A549, breast (MCF-7, liver (HepG2 and colon (HT-29 cancer cells, especially for liver and lung cancer cells. In addition, rutin, 2-hydrocinnamic acid and epicatechin were identified in the extract, which might contribute to antioxidant and antiproliferative activities.

  12. Ultrasound assisted two-stage biodiesel synthesis from non-edible Schleichera triguga oil using heterogeneous catalyst: Kinetics and thermodynamic analysis.

    Science.gov (United States)

    Sarve, Antaram N; Varma, Mahesh N; Sonawane, Shriram S

    2016-03-01

    Present work deals with the ultrasound-assisted biodiesel production from low cost, substantial acid value kusum (Schleichera triguga) oil using a two-step method of esterification in presence of acid (H2SO4) catalyst followed by transesterification using a basic heterogeneous barium hydroxide (Ba(OH)2) catalyst. The initial acid value of kusum oil was reduced from 21.65 to 0.84 mg of KOH/g of oil, by acid catalyzed esterification with 4:1 methanol to oil molar ratio, catalyst concentration 1% (v/v), ultrasonic irradiation time 20 min at 40 °C. Then, Ba(OH)2 concentration of 3% (w/w), methanol to oil molar ratio of 9:1, ultrasonic irradiation time of 80 min, and temperature of 50 °C was found to be the optimum conditions for transesterification step and triglyceride conversion of 96.8% (wt) was achieved. This paper also examined the kinetics as well as the evaluation of thermodynamic parameters for both esterification and transesterification reactions. The lower value of activation energy and higher values of kinetic constants indicated a fast rate of reaction, which could be attributed to the physical effect of emulsification, in which the microturbulence generated due to radial motion of bubbles, creates an intimate mixing of the immiscible reactants causing the increase in the interfacial area, giving faster reaction kinetics. The positive values of Gibbs-free energy (ΔG), enthalpy (ΔH) and negative value of entropy (ΔS) revealed that both the esterification and transesterification were non-spontaneous, endothermic and endergonic reactions. Therefore, the present work has not only established the escalation obtained due to ultrasonication but also exemplified the two-step approach for synthesis of biodiesel from non-edible kusum oil based on the use of heterogeneous catalyst for the transesterification step. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Fast determination of trace elements in organic fertilizers using a cup-horn reactor for ultrasound-assisted extraction and fast sequential flame atomic absorption spectrometry.

    Science.gov (United States)

    Teixeira, Leonel Silva; Vieira, Heulla Pereira; Windmöller, Cláudia Carvalhinho; Nascentes, Clésia Cristina

    2014-02-01

    A fast and accurate method based on ultrasound-assisted extraction in a cup-horn sonoreactor was developed to determine the total content of Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn in organic fertilizers by fast sequential flame atomic absorption spectrometry (FS FAAS). Multivariate optimization was used to establish the optimal conditions for the extraction procedure. An aliquot containing approximately 120 mg of the sample was added to a 500 µL volume of an acid mixture (HNO3/HCl/HF, 5:3:3, v/v/v). After a few minutes, 500 µL of deionized water was added and eight samples were simultaneously sonicated for 10 min at 50% amplitude, allowing a sample throughput of 32 extractions per hour. The performance of the method was evaluated with a certified reference material of sewage sludge (CRM 029). The precision, expressed as the relative standard deviation, ranged from 0.58% to 5.6%. The recoveries of analytes were found to 100%, 109%, 96%, 92%, 101%, 104% and 102% for Cd, Cr, Cu, Mn, Ni, Pb and Zn, respectively. The linearity, limit of detection and limit of quantification were calculated and the values obtained were adequate for the quality control of organic fertilizers. The method was applied to the analysis of several commercial organic fertilizers and organic wastes used as fertilizers, and the results were compared with those obtained using the microwave digestion procedure. A good agreement was found between the results obtained by microwave and ultrasound procedures with recoveries ranging from 80.4% to 117%. Two organic waste samples were not in accordance with the Brazilian legislation regarding the acceptable levels of contaminants. © 2013 Published by Elsevier B.V.

  14. Ultrasound-assisted single-drop microextraction for the determination of cadmium in vegetable oils using high-resolution continuum source electrothermal atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Almeida, Jorge S.; Anunciação, Taiana A.; Brandão, Geovani C.; Dantas, Alailson F.; Lemos, Valfredo A.

    2015-01-01

    This work presents an ultrasound-assisted single-drop microextraction procedure for the determination of cadmium in vegetable oils using high-resolution continuum source electrothermal atomic absorption spectrometry. Some initial tests showed that the best extraction efficiency was obtained when using ultrasound instead of mechanical agitation, indicating that acoustic cavitation improved the extraction process. Nitric, hydrochloric and acetic acids were evaluated for use in the extraction process, and HNO 3 gave the best results. A two-level full-factorial design was applied to investigate the best conditions for the extraction of Cd from the oil samples. The influences of the sonication amplitude, time and temperature of the extraction were evaluated. The results of the design revealed that all of the variables had a significant effect on the experimental results. Afterward, a Box–Behnken design was applied to determine the optimum conditions for the determination of cadmium in vegetable oil samples. According to a multivariate study, the optimum conditions were as follows: sonication amplitude of 60%, extraction time of 15 min, extraction temperature of 46 °C and 0.1 mol L −1 HNO 3 as the extractor solution. Under optimized conditions, the developed method allows for the determination of Cd in oil samples with a limit of quantification of 7.0 ng kg −1 . Addition and recovery experiments were performed in vegetable oil samples to evaluate the accuracy of the method, and the recoveries obtained varied from 90% to 115%. The samples were also analyzed after the acid digestion procedure, and the paired t-test (95% confidence level) did not show significant differences from the proposed method. - Highlights: • The determination of cadmium in vegetable oils was developed using UA-SDME. • HR-CS ET-AAS was employed as a detection technique with direct drop sampling. • The procedure allowed for a reduction in the consumption of reagents and samples

  15. Ultrasonically assisted hydrothermal synthesis of activated carbon-HKUST-1-MOF hybrid for efficient simultaneous ultrasound-assisted removal of ternary organic dyes and antibacterial investigation: Taguchi optimization.

    Science.gov (United States)

    Azad, F Nasiri; Ghaedi, M; Dashtian, K; Hajati, S; Pezeshkpour, V

    2016-07-01

    Activated carbon (AC) composite with HKUST-1 metal organic framework (AC-HKUST-1 MOF) was prepared by ultrasonically assisted hydrothermal method and characterized by FTIR, SEM and XRD analysis and laterally was applied for the simultaneous ultrasound-assisted removal of crystal violet (CV), disulfine blue (DSB) and quinoline yellow (QY) dyes in their ternary solution. In addition, this material, was screened in vitro for their antibacterial actively against Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (PAO1) bacteria. In dyes removal process, the effects of important variables such as initial concentration of dyes, adsorbent mass, pH and sonication time on adsorption process optimized by Taguchi approach. Optimum values of 4, 0.02 g, 4 min, 10 mg L(-1) were obtained for pH, AC-HKUST-1 MOF mass, sonication time and the concentration of each dye, respectively. At the optimized condition, the removal percentages of CV, DSB and QY were found to be 99.76%, 91.10%, and 90.75%, respectively, with desirability of 0.989. Kinetics of adsorption processes follow pseudo-second-order model. The Langmuir model as best method with high applicability for representation of experimental data, while maximum mono layer adsorption capacity for CV, DSB and QY on AC-HKUST-1 estimated to be 133.33, 129.87 and 65.37 mg g(-1) which significantly were higher than HKUST-1 as sole material with Qm to equate 59.45, 57.14 and 38.80 mg g(-1), respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Ultrasound-assisted synthesis of zinc molybdate nanocrystals and molybdate-doped epoxy/PDMS nanocomposite coatings for Mg alloy protection.

    Science.gov (United States)

    Eduok, Ubong; Szpunar, Jerzy

    2018-06-01

    Zinc molybdate (ZM) is a safer anticorrosive additive for cooling systems when compared with chromates and lead salts, due to its insolubility in aqueous media. For most molybdate pigments, their molybdate anion (MoO 4 -2 ) acts as an anionic inhibitor and its passivation capacity is comparable with chromate anion (CrO 4 -2 ). To alleviate the environmental concerns involving chromates-based industrial protective coatings, we have proposed new alternative in this work. We have synthesized ZM nanocrystals via ultrasound-assisted process and encapsulated them within an epoxy/PDMS coating towards corrosion protection. The surface morphology and mechanical properties of these ZM doped epoxy/PDMS nanocomposite coatings is exhaustively discussed to show the effect of ZM content on protective properties. The presence of ZM nanocrystals significantly contributed to the corrosion barrier performance of the coating while the amount of ZM nanocrystals needed to prepare an epoxy coating with optimum barrier performance was established. Beyond 2 wt% ZM concentration, the siloxane-structured epoxy coating network became saturated with ZM pigments. This further broadened inherent pores channels, leading to the percolation of corrosion chloride ions through the coating. SEM evidence has revealed proof of surface delamination on ZM3 coating. A model mechanism of corrosion resistance has been proposed for ZM doped epoxy/PDMS nanocomposite coatings from exhaustive surface morphological investigations and evidence. This coating matrix may have emerging applications in cooling systems as anticorrosive surface paints as well as create an avenue for environmental corrosion remediation. Copyright © 2018 Elsevier B.V. All rights reserved.

  17. Ultrasound assisted extraction combined with dispersive liquid-liquid microextraction (US-DLLME)-a fast new approach to measure phthalate metabolites in nails.

    Science.gov (United States)

    Alves, Andreia; Vanermen, Guido; Covaci, Adrian; Voorspoels, Stefan

    2016-09-01

    A new, fast, and environmentally friendly method based on ultrasound assisted extraction combined with dispersive liquid-liquid microextraction (US-DLLME) was developed and optimized for assessing the levels of seven phthalate metabolites (including the mono(ethyl hexyl) phthalate (MEHP), mono(2-ethyl-5-hydroxyhexyl) phthalate (5-OH-MEHP), mono(2-ethyl-5-oxohexyl) phthalate (5-oxo-MEHP), mono-n-butyl phthalate (MnBP), mono-isobutyl phthalate (MiBP), monoethyl phthalate (MEP), and mono-benzyl phthalate (MBzP)) in human nails by UPLC-MS/MS. The optimization of the US-DLLME method was performed using a Taguchi combinatorial design (L9 array). Several parameters such as extraction solvent, solvent volume, extraction time, acid, acid concentration, and vortex time were studied. The optimal extraction conditions achieved were 180 μL of trichloroethylene (extraction solvent), 2 mL trifluoroacetic acid in methanol (2 M), 2 h extraction and 3 min vortex time. The optimized method had a good precision (6-17 %). The accuracy ranged from 79 to 108 % and the limit of method quantification (LOQm) was below 14 ng/g for all compounds. The developed US-DLLME method was applied to determine the target metabolites in 10 Belgian individuals. Levels of the analytes measured in nails ranged between <12 and 7982 ng/g. The MEHP, MBP isomers, and MEP were the major metabolites and detected in every sample. Miniaturization (low volumes of organic solvents used), low costs, speed, and simplicity are the main advantages of this US-DLLME based method. Graphical Abstract Extraction and phase separation of the US-DLLME procedure.

  18. Ultrasound-assisted single-drop microextraction for the determination of cadmium in vegetable oils using high-resolution continuum source electrothermal atomic absorption spectrometry

    Science.gov (United States)

    Almeida, Jorge S.; Anunciação, Taiana A.; Brandão, Geovani C.; Dantas, Alailson F.; Lemos, Valfredo A.; Teixeira, Leonardo S. G.

    2015-05-01

    This work presents an ultrasound-assisted single-drop microextraction procedure for the determination of cadmium in vegetable oils using high-resolution continuum source electrothermal atomic absorption spectrometry. Some initial tests showed that the best extraction efficiency was obtained when using ultrasound instead of mechanical agitation, indicating that acoustic cavitation improved the extraction process. Nitric, hydrochloric and acetic acids were evaluated for use in the extraction process, and HNO3 gave the best results. A two-level full-factorial design was applied to investigate the best conditions for the extraction of Cd from the oil samples. The influences of the sonication amplitude, time and temperature of the extraction were evaluated. The results of the design revealed that all of the variables had a significant effect on the experimental results. Afterward, a Box-Behnken design was applied to determine the optimum conditions for the determination of cadmium in vegetable oil samples. According to a multivariate study, the optimum conditions were as follows: sonication amplitude of 60%, extraction time of 15 min, extraction temperature of 46 °C and 0.1 mol L- 1 HNO3 as the extractor solution. Under optimized conditions, the developed method allows for the determination of Cd in oil samples with a limit of quantification of 7.0 ng kg- 1. Addition and recovery experiments were performed in vegetable oil samples to evaluate the accuracy of the method, and the recoveries obtained varied from 90% to 115%. The samples were also analyzed after the acid digestion procedure, and the paired t-test (95% confidence level) did not show significant differences from the proposed method.

  19. A Retrospective Comparison of Ultrasound-Assisted Catheter-Directed Thrombolysis and Catheter-Directed Thrombolysis Alone for Treatment of Proximal Deep Vein Thrombosis

    International Nuclear Information System (INIS)

    Tichelaar, Vladimir Y. I. G.; Brodin, Ellen E.; Vik, Anders; Isaksen, Trond; Skjeldestad, Finn Egil; Kumar, Satish; Trasti, Nora C.; Singh, Kulbir; Hansen, John-Bjarne

    2016-01-01

    BackgroundRecent studies have suggested that catheter-directed thrombolysis (CDT) reduces development of post-thrombotic syndrome (PTS). Ultrasound-assisted CDT (USCDT) might enhance the efficiency of thrombolysis. We aimed to compare USCDT with CDT on efficacy, safety, development of PTS, and quality of life after long-term follow-up.MethodsWe describe a retrospective case series of 94 consecutive patients admitted with iliofemoral or more proximal deep vein thrombosis (DVT) to the University Hospital from 2002 to 2011, treated either with CDT or USCDT. Scheduled follow-up visits took place between April 2013 and January 2014. Venography measured the degree of residual luminal obstruction of the affected veins. Each patient completed the Short Form 36-item health survey assessment and the Venous Insufficiency Epidemiological and Economic Study-Quality of Life/Symptoms questionnaires. PTS was assessed using the Villalta scale.ResultsRisk factors of DVT were equally distributed between groups. In the USCDT group, we observed a significant decline in the duration of thrombolytic treatment (<48 h: 27 vs. 10 %), shortened hospital stay (median 6.0 days (IQR 5.0–9.0) vs. 8.0 (IQR 5.8–12.0)), and less implantation of (intravenous) stents (30 vs. 55 %). There was no difference in patency (76 vs. 79 % fully patent), prevalence of PTS (52 vs. 55 %), or quality of life between groups after long-term follow-up (median 65 months, range: 15–141).ConclusionsIn this observational study, USCDT was associated with shortened treatment duration, shorter hospital stay, and less intravenous stenting, compared to CDT alone without affecting the long-term prevalence of PTS or quality of life.

  20. Enhancement of thermal and mechanical properties of poly(MMA-co-BA)/Cloisite 30B nanocomposites by ultrasound-assisted in-situ emulsion polymerization.

    Science.gov (United States)

    Sharma, Sachin; Kumar Poddar, Maneesh; Moholkar, Vijayanand S

    2017-05-01

    This study reports synthesis and characterization of poly(MMA-co-BA)/Cloisite 30B (organo-modified montmorillonite clay) nanocomposites by ultrasound-assisted in-situ emulsion polymerization. Copolymers have been synthesized with MMA:BA monomer ratio of 4:1, and varying clay loading (1-5wt% monomer). The poly(MMA-co-BA)/Cloisite 30B nanocomposites have been characterized for their thermal and mechanical properties. Ultrasonically synthesized nanocomposites have been revealed to possess higher thermal degradation resistance and mechanical strength than the nanocomposites synthesized using conventional techniques. These properties, however, show an optimum (or maxima) with clay loading. The maximum values of thermal and mechanical properties of the nanocomposites with optimum clay loading are as follows. Thermal degradation temperatures: T 10% =320°C (4wt%), T 50 =373°C (4wt%), maximum degradation temperature=384°C (4wt%); glass transition temperature=64.8°C (4wt%); tensile strength=20MPa (2wt%), Young's modulus=1.31GPa (2wt%), Percentage elongation=17.5% (1wt%). Enhanced properties of poly(MMA-co-BA)/Cloisite 30B nanocomposites are attributed to effective exfoliation and dispersion of clay nanoparticles in copolymer matrix due to intense micro-convection induced by ultrasound and cavitation. Clay platelets help in effective heat absorption with maximum surface interaction/adhesion that results in increased thermal resistivity of nanocomposites. Hindered motion of the copolymer chains due to clay platelets results in enhancement of tensile strength and Young's modulus of nanocomposite. Rheological (liquid) study of the nanocomposites reveals that nanocomposites have higher yield stress and infinite shear viscosity than neat copolymer. Nonetheless, nanocomposites still display shear thinning behavior - which is typical of the neat copolymer. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Ultrasound-assisted single-drop microextraction for the determination of cadmium in vegetable oils using high-resolution continuum source electrothermal atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Jorge S.; Anunciação, Taiana A. [Departamento de Química Analítica, Instituto de Química, Universidade Federal da Bahia, Campus Universitário de Ondina, Salvador, Bahia 40170-280 (Brazil); Brandão, Geovani C. [Departamento de Química Analítica, Instituto de Química, Universidade Federal da Bahia, Campus Universitário de Ondina, Salvador, Bahia 40170-280 (Brazil); INCT de Energia e Ambiente, Instituto de Química, Universidade Federal da Bahia, Campus Universitário de Ondina, Salvador, Bahia 40170-280 (Brazil); Dantas, Alailson F. [Departamento de Química Analítica, Instituto de Química, Universidade Federal da Bahia, Campus Universitário de Ondina, Salvador, Bahia 40170-280 (Brazil); Lemos, Valfredo A. [Laboratório de Química Analítica (LQA), Universidade Estadual do Sudoeste da Bahia, Campus de Jequié, Jequié, Bahia 45506-191 (Brazil); and others

    2015-05-01

    This work presents an ultrasound-assisted single-drop microextraction procedure for the determination of cadmium in vegetable oils using high-resolution continuum source electrothermal atomic absorption spectrometry. Some initial tests showed that the best extraction efficiency was obtained when using ultrasound instead of mechanical agitation, indicating that acoustic cavitation improved the extraction process. Nitric, hydrochloric and acetic acids were evaluated for use in the extraction process, and HNO{sub 3} gave the best results. A two-level full-factorial design was applied to investigate the best conditions for the extraction of Cd from the oil samples. The influences of the sonication amplitude, time and temperature of the extraction were evaluated. The results of the design revealed that all of the variables had a significant effect on the experimental results. Afterward, a Box–Behnken design was applied to determine the optimum conditions for the determination of cadmium in vegetable oil samples. According to a multivariate study, the optimum conditions were as follows: sonication amplitude of 60%, extraction time of 15 min, extraction temperature of 46 °C and 0.1 mol L{sup −1} HNO{sub 3} as the extractor solution. Under optimized conditions, the developed method allows for the determination of Cd in oil samples with a limit of quantification of 7.0 ng kg{sup −1}. Addition and recovery experiments were performed in vegetable oil samples to evaluate the accuracy of the method, and the recoveries obtained varied from 90% to 115%. The samples were also analyzed after the acid digestion procedure, and the paired t-test (95% confidence level) did not show significant differences from the proposed method. - Highlights: • The determination of cadmium in vegetable oils was developed using UA-SDME. • HR-CS ET-AAS was employed as a detection technique with direct drop sampling. • The procedure allowed for a reduction in the consumption of reagents and

  2. Quality assessment of trace Cd and Pb contaminants in Thai herbal medicines using ultrasound-assisted digestion prior to flame atomic absorption spectrometry

    Directory of Open Access Journals (Sweden)

    Watsaka Siriangkhawut

    2017-10-01

    Full Text Available A simple, efficient, and reliable ultrasound-assisted digestion (UAD procedure was used for sample preparation prior to quantitative determination of trace Cd and Pb contaminants in herbal medicines using flame atomic absorption spectrometry. The parameters influencing UAD such as the solvent system, sample mass, presonication time, sonication time, and digestion temperature were evaluated. The efficiency of the proposed UAD procedure was evaluated by comparing with conventional acid digestion (CAD procedure. Under the optimum conditions, linear calibration graphs in a range of 2–250 μg/L for Cd, and 50–1000 μg/L for Pb were obtained with detection limits of 0.56 μg/L and 10.7 μg/L for Cd and Pb, respectively. The limit of quantification for Cd and Pb were 1.87 μg/L and 40.3 μg/L, respectively. The repeatability for analysis of 10 μg/L for Cd and 100 μg/L for Pb was 2.3% and 2.6%, respectively. The accuracy of the proposed method was evaluated by rice flour certified reference materials. The proposed method was successfully applied for analysis of trace Cd and Pb in samples of various types of medicinal plant and traditional medicine consumed in Thailand. Most herbal medicine samples were not contaminated with Cd or Pb. The contaminant levels for both metals were still lower than the maximum permissible levels of elements in medicinal plant materials and finished herbal products sets by the Ministry of Public Health of Thailand. The exception was the high level of Cd contamination found in two samples of processed medicinal plants.

  3. Thermotropic Ionic Liquid Crystals

    Science.gov (United States)

    Axenov, Kirill V.; Laschat, Sabine

    2011-01-01

    The last five years’ achievements in the synthesis and investigation of thermotropic ionic liquid crystals are reviewed. The present review describes the mesomorphic properties displayed by organic, as well as metal-containing ionic mesogens. In addition, a short overview on the ionic polymer and self-assembled liquid crystals is given. Potential and actual applications of ionic mesogens are also discussed. PMID:28879986

  4. Thermotropic Ionic Liquid Crystals.

    Science.gov (United States)

    Axenov, Kirill V; Laschat, Sabine

    2011-01-14

    The last five years' achievements in the synthesis and investigation of thermotropic ionic liquid crystals are reviewed. The present review describes the mesomorphic properties displayed by organic, as well as metal-containing ionic mesogens. In addition, a short overview on the ionic polymer and self-assembled liquid crystals is given. Potential and actual applications of ionic mesogens are also discussed.

  5. Thermotropic Ionic Liquid Crystals

    OpenAIRE

    Axenov, Kirill V.; Laschat, Sabine

    2011-01-01

    The last five years’ achievements in the synthesis and investigation of thermotropic ionic liquid crystals are reviewed. The present review describes the mesomorphic properties displayed by organic, as well as metal-containing ionic mesogens. In addition, a short overview on the ionic polymer and self-assembled liquid crystals is given. Potential and actual applications of ionic mesogens are also discussed.

  6. Ultrasound assisted co-precipitation of nanostructured CuO-ZnO-Al2O3 over HZSM-5: effect of precursor and irradiation power on nanocatalyst properties and catalytic performance for direct syngas to DME.

    Science.gov (United States)

    Allahyari, Somaiyeh; Haghighi, Mohammad; Ebadi, Amanollah; Hosseinzadeh, Shahin

    2014-03-01

    Nanostructured CuO-ZnO-Al2O3/HZSM-5 was synthesized from nitrate and acetate precursors using ultrasound assisted co-precipitation method under different irradiation powers. The CuO-ZnO-Al2O3/HZSM-5 nanocatalysts were characterized using XRD, FESEM, BET, FTIR and EDX Dot-mapping analyses. The results indicated precursor type and irradiation power have significant influences on phase structure, morphology, surface area and functional groups. It was observed that the acetate formulated CuO-ZnO-Al2O3/HZSM-5 nanocatalyst have smaller CuO crystals with better dispersion and stronger interaction between components in comparison to nitrate based nanocatalysts. Ultrasound assisted co-precipitation synthesis method resulted in nanocatalyst with more uniform morphology compared to conventional method and increasing irradiation power yields smaller particles with better dispersion and higher surface area. Additionally the crystallinity of CuO is lower at high irradiation powers leading to stronger interaction between metal oxides. The nanocatalysts performance were tested at 200-300 °C, 10-40 bar and space velocity of 18,000-36,000 cm(3)/g h with the inlet gas composition of H2/CO = 2/1 in a stainless steel autoclave reactor. The acetate based nanocatalysts irradiated with higher levels of power exhibited better reactivity in terms of CO conversion and DME yield. While there is an optimal temperature for CO conversion and DME yield in direct synthesis of DME, CO conversion and DME yield both increase with the pressure increase. Furthermore ultrasound assisted co-precipitation method yields more stable CuO-ZnO-Al2O3/HZSM-5 nanocatalyst while conventional precipitated nanocatalyst lost their activity ca. 18% and 58% in terms of CO conversion and DME yield respectively in 24 h time on stream test.

  7. Determination of gardenia yellow colorants in soft drink, pastry, instant noodles with ultrasound-assisted extraction by high performance liquid chromatography-electrospray ionization tandem mass spectrum.

    Science.gov (United States)

    Zhou, Wei-E; Zhang, Yuan; Li, Yang; Ling, Yun; Li, Hong-Na; Li, Shao-Hui; Jiang, Shou-Jun; Ren, Zhi-Qin; Huang, Zhi-Qiang; Zhang, Feng

    2016-05-13

    A novel, rapid and simple analytical method was developed for the quantitative determination of crocin, crocetin and geniposide in soft drink, pastry and instant noodles. The solid samples were relatively homogenized into powders and fragments. The gardenia yellow colorants were successively extracted with methanol using ultrasound-assisted extraction. The analytes were quantitatively measured in the extracts by liquid chromatography coupled with electrospray ionization tandem mass spectrometry. High correlation coefficients (r(2)>0.995) of crocin, crocetin and geniposide were obtained within their linear ranges respectively (50-1000ng/mL, 50-1000ng/mL, 15-240ng/mL) by external standard method. The limits of detection (LODs) were 0.02μg/g for crocin, 0.01μg/g for crocetin and 0.002μg/g for geniposide. And the limits of quantitation (LOQs) were in the ranges of 0.05-0.45μg/g for crocin, and in the ranges of 0.042-0.32μg/g for crocetin, and in the ranges of 0.02-0.15μg/g for geniposide in soft drink, pastry and instant noodles samples. The average recoveries of crocin, crocetin and geniposide ranged from 81.3% to 117.6% in soft drink, pastry and instant noodles. The intra- and inter-day precisions were respectively in the range of 1.3-4.8% and 1.7-11.8% in soft drink, pastry and instant noodle. The developed methods were successfully validated and applied to the soft drink, pastry, and instant noodles collected from the located market in Beijing from China. Crocin, crocetin and geniposide were detected in the collected samples. The average concentrations ranged from 0.84 to 4.20mg/g for crocin, and from 0.62 to 3.11mg/g for crocetin, and from 0.18 to 0.79mg/g for gardenia in various food samples. The method can provide evidences for government to determine gardenia yellow pigments and geniposide in food. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Utility of ultrasound assisted-cloud point extraction and spectophotometry as a preconcentration and determination tool for the sensitive quantification of mercury species in fish samples

    Science.gov (United States)

    Altunay, Nail

    2018-01-01

    The current study reports, for the first time, the development of a new analytical method employing ultrasound assisted-cloud point extraction (UA-CPE) for the extraction of CH3Hg+ and Hg2 + species from fish samples. Detection and quantification of mercury species were performed at 550 nm by spectrophotometry. The analytical variables affecting complex formation and extraction efficiency were extensively evaluated and optimized by univariate method. Due to behave 14-fold more sensitive and selective of thiophene 2,5-dicarboxylic acid (H2TDC) to Hg2 + ions than CH3Hg+ in presence of mixed surfactant, Tween 20 and SDS at pH 5.0, the amounts of free Hg2 + and total Hg were spectrophotometrically established at 550 nm by monitoring Hg2 + in the pretreated- and extracted-fish samples in ultrasonic bath to speed up extraction using diluted acid mixture (1:1:1, v/v, 4 mol L- 1 HNO3, 4 mol L- 1 HCl, and 0.5 mol L- 1 H2O2), before and after pre-oxidation with permanganate in acidic media. The amount of CH3Hg+ was calculated from difference between total Hg and Hg2 + amounts. The UA-CPE method showed to be suitable for the extraction and determination of mercury species in certified reference materials. The results were in a good agreement (with Student's t-test at 95% confidence limit) with the certified values, and the relative standard deviation was lower than 3.2%. The limits of detection have been 0.27 and 1.20 μg L- 1, for Hg2 + from aqueous calibration solutions and matrix-matched calibration solutions spiked before digestion, respectively, while it is 2.43 μg L- 1 for CH3Hg+ from matrix-matched calibration solutions. A significant matrix effect was not observed from comparison of slopes of both calibration curves, so as to represent the sample matrix. The method was applied to fish samples for speciation analysis of Hg2 + and CH3Hg+. In terms of speciation, while total Hg is detected in range of 2.42-32.08 μg kg- 1, the distribution of mercury in fish were in

  9. Ultrasound-assisted green economic synthesis of hydroxyapatite nanoparticles using eggshell biowaste and study of mechanical and biological properties for orthopedic applications.

    Science.gov (United States)

    Ingole, Vijay H; Hany Hussein, Kamal; Kashale, Anil A; Ghule, Kalyani; Vuherer, Tomaž; Kokol, Vanja; Chang, Jia-Yaw; Ling, Yong-Chien; Vinchurkar, Aruna; Dhakal, Hom N; Ghule, Anil V

    2017-11-01

    Nanostructured hydroxyapatite (HAp) is the most favorable candidate biomaterial for bone tissue engineering because of its bioactive and osteoconductive properties. Herein, we report for the first time ultrasound-assisted facile and economic approach for the synthesis of nanocrystalline hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 ) using recycled eggshell biowaste referred as EHAp. The process involves the reaction of eggshell biowaste as a source of calcium and ammonium dihydrogen orthophosphate as a phosphate source. Ultrasound-mediated chemical synthesis of hydroxyapatite (HAp) is also carried out using similar approach wherein commercially available calcium hydroxide and ammonium dihydrogen orthophosphate were used as calcium and phosphate precursors, respectively and referred as CHAp for better comparison. The prepared materials were characterized by X-ray diffraction, field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and Raman spectroscopy to determine crystal structure, particle morphology, and the presence of chemical functional groups. The nanocrystalline EHAp and CHAp were observed to have spherical morphology with uniform size distribution. Furthermore, mechanical properties such as Vickers hardness, fracture toughness, and compression tests have been studied of the EHAp and CHAp samples showing promising results. Mechanical properties show the influence of calcination at 600°C EHAp and CHAp material. After calcination, in the case of EHAp material an average hardness, mechanical strength, elastic modulus, and fracture toughness were found 552 MPa, 46.6 MPa, 2824 MPa, and 3.85 MPa m 1/2 , respectively, while in the case of CHAp 618 MPa, 47.5 MPa, 2071 MPa, and 3.13 MPa m 1/2 . In vitro cell studies revealed that the EHAp and CHAp nanoparticles significantly increased the attachment and proliferation of the hFOB cells. Here, we showed that EHAp and CHAp provide promising biocompatible materials that do not affect the cell

  10. Lithium polymer cell assembled by in situ chemical cross-linking of ionic liquid electrolyte with phosphazene-based cross-linking agent

    International Nuclear Information System (INIS)

    Choi, Ji-Ae; Kang, Yongku; Kim, Dong-Won

    2013-01-01

    Highlights: ► Ionic liquid-based cross-linked gel polymer electrolytes were synthesized and their electrochemical properties were investigated. ► Lithium polymer cells with in situ cross-linked gel polymer electrolytes exhibited reversible cycling behavior with good capacity retention. ► The use of ionic liquid-based cross-linked gel polymer electrolytes significantly improved the thermal stability of the cells. -- Abstract: Ionic liquid-based cross-linked gel polymer electrolytes were prepared with a phosphazene-based cross-linking agent, and their electrochemical properties were investigated. Lithium polymer cells composed of lithium anode and LiCoO 2 cathode were assembled with ionic liquid-based cross-linked gel polymer electrolyte and their cycling performance was evaluated. The interfacial adhesion between the electrodes and the electrolyte by in situ chemical cross-linking resulted in stable capacity retention of the cell. A reduction in the ionic mobility in both the electrolyte and the electrode adversely affected discharge capacity and high rate performance of the cell. DSC studies demonstrated that the use of ionic liquid-based cross-linked gel polymer electrolytes provided a significant improvement in the thermal stability of the cell

  11. Acidic Ionic Liquids.

    Science.gov (United States)

    Amarasekara, Ananda S

    2016-05-25

    Ionic liquid with acidic properties is an important branch in the wide ionic liquid field and the aim of this article is to cover all aspects of these acidic ionic liquids, especially focusing on the developments in the last four years. The structural diversity and synthesis of acidic ionic liquids are discussed in the introduction sections of this review. In addition, an unambiguous classification system for various types of acidic ionic liquids is presented in the introduction. The physical properties including acidity, thermo-physical properties, ionic conductivity, spectroscopy, and computational studies on acidic ionic liquids are covered in the next sections. The final section provides a comprehensive review on applications of acidic ionic liquids in a wide array of fields including catalysis, CO2 fixation, ionogel, electrolyte, fuel-cell, membrane, biomass processing, biodiesel synthesis, desulfurization of gasoline/diesel, metal processing, and metal electrodeposition.

  12. Thermotropic Ionic Liquid Crystals

    Directory of Open Access Journals (Sweden)

    Sabine Laschat

    2011-01-01

    Full Text Available The last five years’ achievements in the synthesis and investigation of thermotropic ionic liquid crystals are reviewed. The present review describes the mesomorphic properties displayed by organic, as well as metal-containing ionic mesogens. In addition, a short overview on the ionic polymer and self-assembled liquid crystals is given. Potential and actual applications of ionic mesogens are also discussed.

  13. Fullerol ionic fluids

    KAUST Repository

    Fernandes, Nikhil; Dallas, Panagiotis; Rodriguez, Robert; Bourlinos, Athanasios B.; Georgakilas, Vasilios; Giannelis, Emmanuel P.

    2010-01-01

    ®). The ionic fluid was compared to a control synthesized by mixing the partially protonated form (sodium form) of the fullerols with the same oligomeric amine in the same ratio as in the ionic fluids (20 wt% fullerol). In the fullerol fluid the ionic bonding

  14. Ionic Liquid-Liquid Chromatography: A New General Purpose Separation Methodology.

    Science.gov (United States)

    Brown, Leslie; Earle, Martyn J; Gîlea, Manuela A; Plechkova, Natalia V; Seddon, Kenneth R

    2017-08-10

    Ionic liquids can form biphasic solvent systems with many organic solvents and water, and these solvent systems can be used in liquid-liquid separations and countercurrent chromatography. The wide range of ionic liquids that can by synthesised, with specifically tailored properties, represents a new philosophy for the separation of organic, inorganic and bio-based materials. A customised countercurrent chromatograph has been designed and constructed specifically to allow the more viscous character of ionic liquid-based solvent systems to be used in a wide variety of separations (including transition metal salts, arenes, alkenes, alkanes, bio-oils and sugars).

  15. Newly developed liquid-based cytology. TACAS™: cytological appearance and HPV testing using liquid-based sample.

    Science.gov (United States)

    Kubushiro, Kaneyuki; Taoka, Hideki; Sakurai, Nobuyuki; Yamamoto, Yasuhiro; Kurasaki, Akiko; Asakawa, Yasuyuki; Iwahara, Minoru; Takahashi, Kei

    2011-09-01

    Cell profiles determined by the thin-layer advanced cytology assay system (TACAS™), a liquid-based cytology technique newly developed in Japan, were analyzed in this study. Hybrid capture 2 (HC-2) was also performed using the liquid-based samples prepared by TACAS to ascertain its ability to detect human papillomavirus (HPV). Cell collection samples from uterine cervix were obtained from 359 patients and examined cytologically. A HC-2 assay for HPV was carried out in the cell specimens. All specimens were found to show background factors such as leukocytes. After excluding the 5 unsatisfactory cases from the total 354 cases, 82 cases (23.2%) were positive and 272 cases (76.8%) were negative for HPV. Cell specimens from 30 HPV-positive cases and 166 HPV-negative cases were subjected to 4 weeks of preservation at room temperature. Then, when subsequently re-assayed, 28 cases (93.3%) in the former group were found to be HPV positive and 164 cases (98.8%) in the latter group were found to be HPV negative. These results supported the excellent reproducibility of TACAS for HPV testing. A reasonable inference from the foregoing analysis is that TACAS may be distinguished from other liquid-based cytological approaches, such as ThinPrep and SurePath, in that it can retain the cell backgrounds. Furthermore, this study raises the possibility that cell specimens prepared using TACAS could be preserved for at least 4 weeks prior to carrying out a HC-2 assay for HPV.

  16. IONIC LIQUIDS MATERIAL AS MODERN CONTEXT OF CHEMISTRY IN SCHOOL

    Directory of Open Access Journals (Sweden)

    Hernani Hernani

    2016-04-01

    Full Text Available One way to improve students’ chemistry literacy which is demanded in the modernization of modern technology-based chemistry learning is by studying ionic liquids. Low level of scientific literacy of students in Indonesia as revealed in the PISA in 2012 was the main reason of the research. Ionic liquids-based technology are necessary to be applied as a context for learning chemistry because: (1 the attention of the scientific an technology community in the use of ionic liquids as a new generation of green solvent, electrolyte material and fluidic engineering in recent years becomes larger, in line with the strong demands of the industry for the provision of new materials that are reliable, safe, and friendly for various purposes; (2 scientific explanations related to the context of the ionic liquid contains a lot of facts, concepts, principles, laws, models and theories can be used to reinforce the learning content as a media to develop thinking skill (process/competence as demanded by PISA; (3 The modern technology-based ionic liquid can also be used as a discourse to strengthen scientific attitude. The process of synthesis of ionic liquid involves fairly simple organic reagents, so it deserves to be included in the chemistry subject in school.

  17. Fluorescent probe studies of polarity and solvation within room temperature ionic liquids: a review.

    Science.gov (United States)

    Pandey, Shubha; Baker, Sheila N; Pandey, Siddharth; Baker, Gary A

    2012-09-01

    Ionic liquids display an array of useful and sometimes unconventional, solvent features and have attracted considerable interest in the field of green chemistry for the potential they hold to significantly reduce environmental emissions. Some of these points have a bearing on the chemical reactivity of these systems and have also generated interest in the physical and theoretical aspects of solvation in ionic liquids. This review presents an introduction to the field of ionic liquids, followed by discussion of investigations into the solvation properties of neat ionic liquids or mixed systems including ionic liquids as a major or minor component. The ionic liquid based multicomponent systems discussed are composed of other solvents, other ionic liquids, carbon dioxide, surfactants or surfactant solutions. Although we clearly focus on fluorescence spectroscopy as a tool to illuminate ionic liquid systems, the issues discussed herein are of general relevance to discussions of polarity and solvent effects in ionic liquids. Transient solvation measurements carried out by means of time-resolved fluorescence measurements are particularly powerful for their ability to parameterize the kinetics of the solvation process in ionic liquids and are discussed as well.

  18. Electrochemical functionalization of glassy carbon electrode by reduction of diazonium cations in protic ionic liquid

    International Nuclear Information System (INIS)

    Shul, Galyna; Ruiz, Carlos Alberto Castro; Rochefort, Dominic; Brooksby, Paula A.; Bélanger, Daniel

    2013-01-01

    Protic ionic liquid based on 2-methoxypyridine and trifluoroacetic acid was used as electrolyte for the functionalization of a glassy carbon electrode surface by electrochemical reduction of in situ generated 4-chlorobenzene diazonium and 4-nitrobenzene diazonium cations. The diazonium cations were synthesized in an electrochemical cell by reaction of the corresponding amines with NaNO 2 dissolved in protic ionic liquid. The resulting electrografted organic layers exhibit similar properties to those layers obtained by the derivatization from isolated diazonium salts dissolved in protic ionic liquid. Functionalized glassy carbon electrode surfaces were characterized by cyclic voltammetry, Fourier transform infrared and X-ray photoelectron spectroscopies. Atomic force microscopy thickness measurements revealed that, in our experimental conditions, the use of protic ionic liquid led to the formation of film with a thickness of about 1.5 nm. It is also demonstrated that the nitrobenzene chemisorbed on glassy carbon electrode or dissolved in protic ionic liquid undergoes electrochemical conversion to hydroxyaminobenzene

  19. Research progress of SO2 removal from flue gas by functionalized ionic liquids

    Directory of Open Access Journals (Sweden)

    Xinle SHI

    2017-02-01

    Full Text Available Functionalized ionic liquids are receiving increasing attention in the field of flue gas desulfurization due to its unique physical and chemical properties. Research progress on the field of SO2 removal by ionic liquids (ILs including guanidinium-based, amines-based and ether-based ILs is summarized. Industrial application of polymerization ILs and loaded ILs to desulfurization is reviewed. Relevant suggestions on industrial application of ionic liquids based on fundamental research are put forward. The first thing is to develop functional ionic liquid for desulfurization,and thus investigate and propose its desulfurization mechanism and model; the second is to carry out the research work on immobilized ionic liquid, and explore its recycling properties, thus prolonging its service life.

  20. Fullerol ionic fluids

    Science.gov (United States)

    Fernandes, Nikhil; Dallas, Panagiotis; Rodriguez, Robert; Bourlinos, Athanasios B.; Georgakilas, Vasilios; Giannelis, Emmanuel P.

    2010-09-01

    We report for the first time an ionic fluid based on hydroxylated fullerenes (fullerols). The ionic fluid was synthesized by neutralizing the fully protonated fullerol with an amine terminated polyethylene/polypropylene oxide oligomer (Jeffamine®). The ionic fluid was compared to a control synthesized by mixing the partially protonated form (sodium form) of the fullerols with the same oligomeric amine in the same ratio as in the ionic fluids (20 wt% fullerol). In the fullerol fluid the ionic bonding significantly perturbs the thermal transitions and melting/crystallization behavior of the amine. In contrast, both the normalized heat of fusion and crystallization of the amine in the control are similar to those of the neat amine consistent with a physical mixture of the fullerols/amine with minimal interactions. In addition to differences in thermal behavior, the fullerol ionic fluid exhibits a complex viscoelastic behavior intermediate between the neat Jeffamine® (liquid-like) and the control (solid-like).

  1. Nanoscale Ionic Liquids

    Science.gov (United States)

    2006-11-01

    Technical Report 11 December 2005 - 30 November 2006 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Nanoscale Ionic Liquids 5b. GRANT NUMBER FA9550-06-1-0012...Title: Nanoscale Ionic Liquids Principal Investigator: Emmanuel P. Giannelis Address: Materials Science and Engineering, Bard Hall, Cornell University...based fluids exhibit high ionic conductivity. The NFs are typically synthesized by grafting a charged, oligomeric corona onto the nanoparticle cores

  2. Development and Validation of a HPLC-UV Method for the Evaluation of Ellagic Acid in Liquid Extracts of Eugenia uniflora L. (Myrtaceae Leaves and Its Ultrasound-Assisted Extraction Optimization

    Directory of Open Access Journals (Sweden)

    Paulo Isaac Dias Assunção

    2017-01-01

    Full Text Available A simple HPLC-UV method has been developed and validated for the quantification of ellagic acid (EA in ethanol extracts of Eugenia uniflora L. (Myrtaceae leaves. The ultrasound-assisted extraction (UAE optimization was performed using a Box Behnken design (33 combined with response surface methodology to study the effects of the ethanol concentration (%, w/w, extraction time (minutes, and temperature (°C on the EA concentration. The optimized results showed that the highest extraction yield of EA by UAE was 26.0 μg mL−1 when using 44% (w/w ethanol as the solvent, 22 minutes as the extraction time, and 59°C as the extraction temperature. The concentration of EA in relation to the predicted value was 93.7%  ±  0.4. UAE showed a strong potential for EA extraction.

  3. Development and Validation of a HPLC-UV Method for the Evaluation of Ellagic Acid in Liquid Extracts of Eugenia uniflora L. (Myrtaceae) Leaves and Its Ultrasound-Assisted Extraction Optimization.

    Science.gov (United States)

    Assunção, Paulo Isaac Dias; da Conceição, Edemilson Cardoso; Borges, Leonardo Luiz; de Paula, Joelma Abadia Marciano

    2017-01-01

    A simple HPLC-UV method has been developed and validated for the quantification of ellagic acid (EA) in ethanol extracts of Eugenia uniflora L. (Myrtaceae) leaves. The ultrasound-assisted extraction (UAE) optimization was performed using a Box Behnken design (3 3 ) combined with response surface methodology to study the effects of the ethanol concentration (%, w/w), extraction time (minutes), and temperature (°C) on the EA concentration. The optimized results showed that the highest extraction yield of EA by UAE was 26.0  μ g mL -1 when using 44% (w/w) ethanol as the solvent, 22 minutes as the extraction time, and 59°C as the extraction temperature. The concentration of EA in relation to the predicted value was 93.7%  ±  0.4. UAE showed a strong potential for EA extraction.

  4. Ultrasound-assisted extraction of phenolic compounds from Cratoxylum formosum ssp. formosum leaves using central composite design and evaluation of its protective ability against H2O2-induced cell death.

    Science.gov (United States)

    Yingngam, Bancha; Monschein, Marlene; Brantner, Adelheid

    2014-09-01

    To optimize the processing parameters for phenolic compounds extracted from Cratoxylum formosum ssp. formosum leaves using an ultrasound-assisted extraction and to evaluate its protective ability against H2O2-induced cell death. The influence of three independent variables including ethanol concentration (%), extraction temperature (°C) and extraction time (min) on the extraction yield of phenolic compounds were optimized using a central composite design-based response surface methodology. The obtained extract was assessed for its antioxidant activity by DPPH(•) and ABTS(•)(+) methods. Cellular protective ability against H2O2-induced cell death was evaluated on HEK293 cells using the MTT assay. The optimal conditions to achieve maximal yields of phenolic compounds were ethanol concentration of 50.33% (v/v), temperature of 65 °C, and extractiontion time of 15 min. The yield of phenolic compounds was (40.00±1.00) mg gallic acid equivalent/g dry powder which matched well with the values predicted from the proposed model. These conditions resulted in a higher efficiency concerning the extraction of phenolics compared to a conventional heat reflux extraction by providing shorter extraction time and reduced energy consumption. 5-O-caffeoylquinic acid identified by high performance liquid chromatography-diode array detector-electron spin ionization-mass spectrometry was the major compound in the obtained extract [(41.66±0.07) mg/g plant extract]. The obtained extract showed a strong ability to scavenge both DPPH(•) and ABTS(•)(+) free radicals and exhibited additionally good ability to protect HEK293 cells death against oxidative stress. These results indicate the suitability of ultrasound-assisted extraction for the extraction of phenolic compounds from Cratoxylum formosum ssp. formosum leaves. This phenolic-enriched extract can be used as valuable antioxidant source for health benefits. Copyright © 2014 Hainan Medical College. Published by Elsevier B.V. All

  5. Electrochemical Model for Ionic Liquid Electrolytes in Lithium Batteries

    International Nuclear Information System (INIS)

    Yoo, Kisoo; Deshpande, Anirudh; Banerjee, Soumik; Dutta, Prashanta

    2015-01-01

    ABSTRACT: Room temperature ionic liquids are considered as potential electrolytes for high performance and safe lithium batteries due to their very low vapor pressure and relatively wide electrochemical and thermal stability windows. Unlike organic electrolytes, ionic liquid electrolytes are molten salts at room temperature with dissociated cations and anions. These dissociated ions interfere with the transport of lithium ions in lithium battery. In this study, a mathematical model is developed for transport of ionic components to study the performance of ionic liquid based lithium batteries. The mathematical model is based on a univalent ternary electrolyte frequently encountered in ionic liquid electrolytes of lithium batteries. Owing to the very high concentration of components in ionic liquid, the transport of lithium ions is described by the mutual diffusion phenomena using Maxwell-Stefan diffusivities, which are obtained from atomistic simulation. The model is employed to study a lithium-ion battery where the electrolyte comprises ionic liquid with mppy + (N-methyl-N-propyl pyrrolidinium) cation and TFSI − (bis trifluoromethanesulfonyl imide) anion. For a moderate value of reaction rate constant, the electric performance results predicted by the model are in good agreement with experimental data. We also studied the effect of porosity and thickness of separator on the performance of lithium-ion battery using this model. Numerical results indicate that low rate of lithium ion transport causes lithium depleted zone in the porous cathode regions as the porosity decreases or the length of the separator increases. The lithium depleted region is responsible for lower specific capacity in lithium-ion cells. The model presented in this study can be used for design of optimal ionic liquid electrolytes for lithium-ion and lithium-air batteries

  6. Radiation stability of diglycolamide functionalized calix[4]arenes in ionic liquid: Solvent extraction, EPR and GC–MS studies

    NARCIS (Netherlands)

    Sengupta, A; Mohapatra, P.K.; Patil, A.B.; Kadam, R.M.; Verboom, Willem

    2016-01-01

    Ionic liquid-based solvent systems containing diglycolamide-functionalized calix[4]arenes (C4DGAs) are efficient for actinide ion extraction from nitric acid feeds. Therefore, the radiolytic stability of three C4DGAs (wide-rim, narrow-rim and both side DGA-functionalized calix[4]arenes) and TODGA

  7. Ionic liquids: an x-ray reflectivity study

    International Nuclear Information System (INIS)

    Sloutskin, E.; Deutsch, M.; Tamam, L.; Ocko, B.; Kuzmenko, I.; Gog, T.

    2005-01-01

    Full Text:Ionic liquids are non-volatile, non-flammable and thermally stable solvents, and as such are promising 'green' replacements for traditional volatile organic solvents. In the last years hundreds of Ionic liquids were synthesized. Due to the Ionic liquids great industrial potential, this number is growing at an exceedingly fast rate. Despite the great importance of the interfacial properties of materials for technological applications and basic science, the atomic-scale surface structure of the Ionic liquids has never been studied previously. In our study, synchrotron x-ray reflectivity and surface tensiometry were employed to obtain the surface structure and thermodynamics of two ionic liquids, based on the 1-alkyl-3-methylimidazolium cations. A molecular layer of a density ∼18% higher than that of the bulk is found to form at the free surface of these liquids. The excess concentration of the oppositely charged ions within the surface layer is determined by chemical substitution of the anion. Finally, the observed layering at the surface is contrasted with our measurements on the behavior of classical aqueous salt solutions

  8. Novel developments in hydrogen storage, hydrogen activation and ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Doroodian, Amir

    2010-12-03

    This dissertation is divided into three chapters. Recently, metal-free hydrogen activation using phosphorous compounds has been reported in science magazine. We have investigated the interaction between hydrogen and phosphorous compounds in presence of strong Lewis acids (chapter one). A new generation of metal-free hydrogen activation, using amines and strong Lewis acids with sterically demanding nature, was already developed in our group. Shortage of high storage capacity using large substitution to improve sterical effect led us to explore the amine borane derivatives, which are explained in chapter two. Due to the high storage capacity of hydrogen in aminoborane derivatives, we have explored these materials to extend hydrogen release. These compounds store hydrogen as proton and hydride on adjacent atoms or ions. These investigations resulted in developing hydrogen storage based on ionic liquids containing methyl guanidinium cation. Then we have continued to develop ionic liquids based on methyl guanidinium cation with different anions, such as tetrafluoro borate (chapter three). We have replaced these anions with transition metal anions to investigate hydrogen bonding and catalytic activity of ionic liquids. This chapter illustrates the world of ionic liquid as a green solvent for organic, inorganic and catalytic reactions and combines the concept of catalysts and solvents based on ionic liquids. The catalytic activity is investigated particularly with respect to the interaction with CO{sub 2}. (orig.)

  9. Pysico-chemical properties of hydrophobic ionic liquids containing1-octylpyridinium, 1-octyl-2-methylpyridinium or1-octyl-4-methylpyridinium cations

    Energy Technology Data Exchange (ETDEWEB)

    Papaiconomou, Nicolas; Salminen, Justin; Lee, Jong-Min; Prausnitz, John M.

    2006-09-15

    This paper reports synthesis of some ionic liquids based on cations 1-octylpyridinium, 1-octyl-2-methylpyridinium or 1-octyl-4-methylpyridinium and anions dicyanamide [N(CN)2]-, bis(trifluoromethylsulfonyl)imide [Tf2N]-, bis(pentafluoroethylsulfonyl)imide [BETI]-, trifluoromethyl sulfonate [TfO]-, nonafluorobutyl sulfonate [NfO]-, tetrafluoroborate [BF4]-, trifluorophenylborate [BF3Ph]- or hexafluoroarsenate [AsF6]-. Melting points, decomposition temperatures, densities, mutual solubilities with water, and viscosities have been measured. Unlike similar ionic liquids containing imidazolium cations, pyridinium ionic liquids studied here are nearly immiscible in water. Viscosities are similar and water content is slightly lower than those for ionic liquids containing imidazolium cations.

  10. Mechanical heterogeneity in ionic liquids

    Science.gov (United States)

    Veldhorst, Arno A.; Ribeiro, Mauro C. C.

    2018-05-01

    Molecular dynamics (MD) simulations of five ionic liquids based on 1-alkyl-3-methylimidazolium cations, [CnC1im]+, have been performed in order to calculate high-frequency elastic moduli and to evaluate heterogeneity of local elastic moduli. The MD simulations of [CnC1im][NO3], n = 2, 4, 6, and 8, assessed the effect of domain segregation when the alkyl chain length increases, and [C8C1im][PF6] assessed the effect of strength of anion-cation interaction. Dispersion curves of excitation energies of longitudinal and transverse acoustic, LA and TA, modes were obtained from time correlation functions of mass currents at different wavevectors. High-frequency sound velocity of LA modes depends on the alkyl chain length, but sound velocity for TA modes does not. High-frequency bulk and shear moduli, K∞ and G∞, depend on the alkyl chain length because of a density effect. Both K∞ and G∞ are strongly dependent on the anion. The calculation of local bulk and shear moduli was accomplished by performing bulk and shear deformations of the systems cooled to 0 K. The simulations showed a clear connection between structural and elastic modulus heterogeneities. The development of nano-heterogeneous structure with increasing length of the alkyl chain in [CnC1im][NO3] implies lower values for local bulk and shear moduli in the non-polar domains. The mean value and the standard deviations of distributions of local elastic moduli decrease when [NO3]- is replaced by the less coordinating [PF6]- anion.

  11. Chromium(VI Removal from Aqueous Solution by Magnetite Coated by a Polymeric Ionic Liquid-Based Adsorbent

    Directory of Open Access Journals (Sweden)

    Thania Alexandra Ferreira

    2017-05-01

    Full Text Available An evaluation of the chromium(VI adsorption capacity of four magnetite sorbents coated with a polymer phase containing polymethacrylic acid or polyallyl-3-methylimidazolium is presented. Factors that influence the chromium(VI removal such as solution pH and contact time were investigated in batch experiments and in stirred tank reactor mode. Affinity and rate constants increased with the molar ratio of the imidazolium. The highest adsorption was obtained at pH 2.0 due to the contribution of electrostatic interactions.

  12. Chromium(VI) Removal from Aqueous Solution by Magnetite Coated by a Polymeric Ionic Liquid-Based Adsorbent

    Science.gov (United States)

    Ferreira, Thania Alexandra; Rodriguez, Jose Antonio; Paez-Hernandez, María Elena; Guevara-Lara, Alfredo; Barrado, Enrique; Hernandez, Prisciliano

    2017-01-01

    An evaluation of the chromium(VI) adsorption capacity of four magnetite sorbents coated with a polymer phase containing polymethacrylic acid or polyallyl-3-methylimidazolium is presented. Factors that influence the chromium(VI) removal such as solution pH and contact time were investigated in batch experiments and in stirred tank reactor mode. Affinity and rate constants increased with the molar ratio of the imidazolium. The highest adsorption was obtained at pH 2.0 due to the contribution of electrostatic interactions. PMID:28772865

  13. Effect of a novel amphipathic ionic liquid on lithium deposition in gel polymer electrolytes

    International Nuclear Information System (INIS)

    Choi, Nam-Soon; Koo, Bonjae; Yeon, Jin-Tak; Lee, Kyu Tae; Kim, Dong-Won

    2011-01-01

    Highlights: · Synthesis of a dimeric ionic liquid. · Gel polymer electrolytes providing uniform lithium deposit pathway. · An amphipathic ionic liquid locates at the interface between an electrolyte-rich phase and a polymer matrix in a gel polymer electrolyte. · The presence of PDMITFSI ionic liquid leads to the suppression of dendritic lithium formation on a lithium metal electrode. - Abstract: A novel dimeric ionic liquid based on imidazolium cation and bis(trifluoromethanesulfonyl) imide (TFSI) anion has been synthesized through a metathesis reaction. Its chemical shift values and thermal properties are identified via 1 H nuclear magnetic resonance (NMR) imaging and differential scanning calorimetry (DSC). The effect of the synthesized dimeric ionic liquid on the interfacial resistance of gel polymer electrolytes is described. Differences in the SEM images of lithium electrodes after lithium deposition with and without the 1,1'-pentyl-bis(2,3-dimethylimidazolium) bis(trifluoromethane-sulfonyl)imide (PDMITFSI) ionic liquid in gel polymer electrolytes are clearly discernible. This occurs because the PDMITFSI ionic liquid with hydrophobic moieties and polar groups modulates lithium deposit pathways onto the lithium metal anode. Moreover, high anodic stability for a gel polymer electrolyte with the PDMITFSI ionic liquid was clearly observed.

  14. Ionic Liquids in Tribology

    Directory of Open Access Journals (Sweden)

    Ichiro Minami

    2009-06-01

    Full Text Available Current research on room-temperature ionic liquids as lubricants is described. Ionic liquids possess excellent properties such as non-volatility, non-flammability, and thermo-oxidative stability. The potential use of ionic liquids as lubricants was first proposed in 2001 and approximately 70 articles pertaining to fundamental research on ionic liquids have been published through May 2009. A large majority of the cations examined in this area are derived from 1,3-dialkylimidazolium, with a higher alkyl group on the imidazolium cation being beneficial for good lubrication, while it reduces the thermo-oxidative stability. Hydrophobic anions provide both good lubricity and significant thermo-oxidative stability. The anions decompose through a tribochemical reaction to generate metal fluoride on the rubbed surface. Additive technology to improve lubricity is also explained. An introduction to tribology as an interdisciplinary field of lubrication is also provided.

  15. Ionic liquids in tribology.

    Science.gov (United States)

    Minami, Ichiro

    2009-06-24

    Current research on room-temperature ionic liquids as lubricants is described. Ionic liquids possess excellent properties such as non-volatility, non-flammability, and thermo-oxidative stability. The potential use of ionic liquids as lubricants was first proposed in 2001 and approximately 70 articles pertaining to fundamental research on ionic liquids have been published through May 2009. A large majority of the cations examined in this area are derived from 1,3-dialkylimidazolium, with a higher alkyl group on the imidazolium cation being beneficial for good lubrication, while it reduces the thermo-oxidative stability. Hydrophobic anions provide both good lubricity and significant thermo-oxidative stability. The anions decompose through a tribochemical reaction to generate metal fluoride on the rubbed surface. Additive technology to improve lubricity is also explained. An introduction to tribology as an interdisciplinary field of lubrication is also provided.

  16. Photophysics of ionic biochromophores

    CERN Document Server

    Brøndsted Nielsen, Steen

    2014-01-01

    This concise guide to studying ionic biochromophores features the first integrated overview of the photophysics of differing classes of biomolecules, from single amino acids to DNA. It includes an appraisal of the latest theories and experimental techniques.

  17. Comparison between dispersive solid-phase and dispersive liquid-liquid microextraction combined with spectrophotometric determination of malachite green in water samples based on ultrasound-assisted and preconcentration under multi-variable experimental design optimization.

    Science.gov (United States)

    Alipanahpour Dil, Ebrahim; Ghaedi, Mehrorang; Asfaram, Arash; Zare, Fahimeh; Mehrabi, Fatemeh; Sadeghfar, Fardin

    2017-11-01

    The ultrasound-assisted dispersive solid-phase microextraction (USA-DSPME) and the ultrasound-assisted dispersive liquid-liquid microextraction (USA-DLLME) developed for as an ultra preconcentration and/or technique for the determination of malachite green (MG) in water samples. Central composite design based on analysis of variance and desirability function guide finding best operational conditions and represent dependency of response to variables viz. volume of extraction, eluent and disperser solvent, pH, adsorbent mass and ultrasonication time has significant influence on methods efficiency. Optimum conditions was set for USA-DSPME as: 1mg CNTs/Zn:ZnO@Ni 2 P-NCs; 4min sonication time and 130μL eluent at pH 6.0. Meanwhile optimum point for USA-DLLME conditions were fixed at pH 6.0; 4min sonication time and 130, 650μL and 10mL of extraction solvent (CHCl 3 ), disperser solvent (ethanol) and sample volume, respectively. Under the above specified best operational conditions, the enrichment factors for the USA-DSPME and USA-DLLME were 88.89 and 147.30, respectively. The methods has linear response in the range of 20.0 to 4000.0ngmL -1 with the correlation coefficients (r) between 0.9980 to 0.9995, while its reasonable detection limits viz. 1.386 to 2.348ngmL -1 and good relative standard deviations varied from 1.1% to 2.8% (n=10) candidate this method for successful monitoring of analyte from various media. The relative recoveries of the MG dye from water samples at spiking level of 500ngmL -1 were in the range between 94.50% and 98.86%. The proposed methods has been successfully applied to the analysis of the MG dye in water samples, and a satisfactory result was obtained. Copyright © 2017. Published by Elsevier B.V.

  18. The potential for ionic liquid electrolytes to stabilise the magnesium interface for magnesium/air batteries

    International Nuclear Information System (INIS)

    Khoo, Timothy; Howlett, Patrick C.; Tsagouria, Maureen; MacFarlane, Douglas R.; Forsyth, Maria

    2011-01-01

    Magnesium/air batteries are a possible high-energy density power source that, to date, have not received strong commercial interest due to issues with the corrosion of the magnesium and evaporation of the electrolyte. In this work we report on the use of ionic liquid based electrolytes to stabilise the metal/electrolyte interface and their impact on the electrochemical performance. Galvanostatic measurements indicate that the water content of the ionic liquid electrolyte plays an important role in the cell discharge characteristics. Surface characterisation using EIS, ATR-FTIR and powder diffraction examined the unique properties of the surface film formed on the magnesium anode.

  19. Fullerol ionic fluids

    KAUST Repository

    Fernandes, Nikhil

    2010-01-01

    We report for the first time an ionic fluid based on hydroxylated fullerenes (fullerols). The ionic fluid was synthesized by neutralizing the fully protonated fullerol with an amine terminated polyethylene/polypropylene oxide oligomer (Jeffamine®). The ionic fluid was compared to a control synthesized by mixing the partially protonated form (sodium form) of the fullerols with the same oligomeric amine in the same ratio as in the ionic fluids (20 wt% fullerol). In the fullerol fluid the ionic bonding significantly perturbs the thermal transitions and melting/crystallization behavior of the amine. In contrast, both the normalized heat of fusion and crystallization of the amine in the control are similar to those of the neat amine consistent with a physical mixture of the fullerols/amine with minimal interactions. In addition to differences in thermal behavior, the fullerol ionic fluid exhibits a complex viscoelastic behavior intermediate between the neat Jeffamine® (liquid-like) and the control (solid-like). © 2010 The Royal Society of Chemistry.

  20. Sensitivities of ionic explosives

    Science.gov (United States)

    Politzer, Peter; Lane, Pat; Murray, Jane S.

    2017-03-01

    We have investigated the relevance for ionic explosive sensitivity of three factors that have been demonstrated to be related to the sensitivities of molecular explosives. These are (1) the maximum available heat of detonation, (2) the amount of free space per molecule (or per formula unit) in the crystal lattice and (3) specific features of the electrostatic potential on the molecular or ionic surface. We find that for ionic explosives, just as for molecular ones, there is an overall tendency for impact sensitivity to increase as the maximum detonation heat release is greater. This means that the usual emphasis upon designing explosives with large heats of detonation needs to be tempered somewhat. We also show that a moderate detonation heat release does not preclude a high level of detonation performance for ionic explosives, as was already demonstrated for molecular ones. Relating the free space per formula unit to sensitivity may require a modified procedure for ionic explosives; this will continue to be investigated. Finally, an encouraging start has been made in linking impact sensitivities to the electrostatic potentials on ionic surfaces, although limited so far to ammonium salts.

  1. Cycling performance of lithium polymer cells assembled by in situ polymerization of a non-flammable ionic liquid monomer

    International Nuclear Information System (INIS)

    Lee, Yoon-Sung; Kim, Dong-Won

    2013-01-01

    Highlights: • Gel polymer electrolytes were synthesized by in situ polymerization of ionic liquid in the lithium polymer cells. • Flammability of the electrolyte was significantly reduced by polymerizing electrolyte containing a non-flammable ionic liquid monomer. • The cells assembled with polymeric ionic liquid-based electrolytes exhibited reversible cycling behavior with good capacity retention. -- Abstract: Lithium polymer cells composed of a lithium negative electrode and a LiCoO 2 positive electrode were assembled with a gel polymer electrolyte obtained by in situ polymerization of an electrolyte solution containing an ionic liquid monomer with vinyl groups. The polymerization of the electrolyte solution containing the non-flammable ionic liquid monomer resulted in a significant reduction of the flammability of the gel polymer electrolytes. The lithium polymer cell assembled with the stable gel polymer electrolyte delivered a discharge capacity of 134.3 mAh g −1 at ambient temperature and exhibited good capacity retention

  2. A new combined method of stable isotope-labeling derivatization-ultrasound-assisted dispersive liquid-liquid microextraction for the determination of neurotransmitters in rat brain microdialysates by ultra high performance liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Zheng, Longfang; Zhao, Xian-En; Zhu, Shuyun; Tao, Yanduo; Ji, Wenhua; Geng, Yanling; Wang, Xiao; Chen, Guang; You, Jinmao

    2017-06-01

    In this work, for the first time, a new hyphenated technique of stable isotope-labeling derivatization-ultrasound-assisted dispersive liquid-liquid microextraction has been developed for the simultaneous determination of monoamine neurotransmitters (MANTs) and their biosynthesis precursors and metabolites. The developed method was based on ultra high performance liquid chromatography tandem mass spectrometry detection using multiple-reaction monitoring mode. A pair of mass spectrometry sensitizing reagents, d 0 -10-methyl-acridone-2-sulfonyl chloride and d 3 -10-methyl-acridone-2-sulfonyl chloride, as stable isotope probes was utilized to facilely label neurotransmitters, respectively. The heavy labeled MANTs standards were prepared and used as internal standards for quantification to minimize the matrix effects in mass spectrometry analysis. Low toxic bromobenzene (extractant) and acetonitrile (dispersant) were utilized in microextraction procedure. Under the optimized conditions, good linearity was observed with the limits of detection (S/N>3) and limits of quantification (S/N>10) in the range of 0.002-0.010 and 0.015-0.040nmol/L, respectively. Meanwhile, it also brought acceptable precision (4.2-8.8%, peak area RSDs %) and accuracy (recovery, 96.9-104.1%) results. This method was successfully applied to the simultaneous determination of monoamine neurotransmitters and their biosynthesis precursors and metabolites in rat brain microdialysates of Parkinson's disease and normal rats. This provided a new method for the neurotransmitters related studies in the future. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Simultaneous Determination of Food-Related Biogenic Amines and Precursor Amino Acids Using in Situ Derivatization Ultrasound-Assisted Dispersive Liquid-Liquid Microextraction by Ultra-High-Performance Liquid Chromatography Tandem Mass Spectrometry.

    Science.gov (United States)

    He, Yongrui; Zhao, Xian-En; Wang, Renjun; Wei, Na; Sun, Jing; Dang, Jun; Chen, Guang; Liu, Zhiqiang; Zhu, Shuyun; You, Jinmao

    2016-11-02

    A simple, rapid, sensitive, selective, and environmentally friendly method, based on in situ derivatization ultrasound-assisted dispersive liquid-liquid microextraction (in situ DUADLLME) coupled with ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) using multiple reaction monitoring (MRM) mode has been developed for the simultaneous determination of food-related biogenic amines and amino acids. A new mass-spectrometry-sensitive derivatization reagent 4'-carbonyl chloride rosamine (CCR) was designed, synthesized, and first reported. Parameters and conditions of in situ DUADLLME and UHPLC-MS/MS were optimized in detail. Under the optimized conditions, the in situ DUADLLME was completed speedily (within 1 min) with high derivatization efficiencies (≥98.5%). With the cleanup and concentration of microextraction step, good analytical performance was obtained for the analytes. The results showed that this method was accurate and practical for quantification of biogenic amines and amino acids in common food samples (red wine, beer, wine, cheese, sausage, and fish).

  4. Rapid and sensitive determination of phytosterols in functional foods and medicinal herbs by using UHPLC-MS/MS with microwave-assisted derivatization combined with dual ultrasound-assisted dispersive liquid-liquid microextraction.

    Science.gov (United States)

    Sun, Jing; Zhao, Xian-En; Dang, Jun; Sun, Xiaoyan; Zheng, Longfang; You, Jinmao; Wang, Xiao

    2017-02-01

    In this work, a hyphenated technique of dual ultrasound-assisted dispersive liquid-liquid microextraction combined with microwave-assisted derivatization followed by ultra high performance liquid chromatography tandem mass spectrometry has been developed for the determination of phytosterols in functional foods and medicinal herbs. Multiple reaction monitoring mode was used for the tandem mass spectrometry detection. A mass spectrometry sensitive reagent, 4'-carboxy-substituted rosamine, has been used as the derivatization reagent for five phytosterols, and internal standard diosgenin was used for the first time. Parameters for the dual microextraction, microwave-assisted derivatization, and ultra high performance liquid chromatography tandem mass spectrometry were all optimized in detail. Satisfactory linearity, recovery, repeatability, accuracy and precision, absence of matrix effect, extremely low limits of detection (0.005-0.015 ng/mL) and limits of quantification (0.030-0.10 ng/mL) were achieved. The proposed method was compared with previously reported methods. It showed better sensitivity, selectivity, and accuracy. The matrix effect was also significantly reduced. The proposed method was successfully applied to the determination of five phytosterols in vegetable oil (sunflower oil, olive oil, corn oil, peanut oil), milk and orange juice (soymilk, peanut milk, orange juice), and medicinal herbs (Ginseng, Ganoderma lucidum, Cordyceps, Polygonum multiflorum) for the quality control of functional foods and medicinal herbs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. A Simple Method for the Simultaneous Determination of Pharmaceuticals and Personal Care Products in River Sediment by Ultrasound-Assisted Extraction Followed by Solid-Phase Microextraction Coupled with Gas Chromatography-Mass Spectrometry.

    Science.gov (United States)

    Díaz, Alejandro; Peña-Alvarez, Araceli

    2017-10-01

    A simple method was developed using ultrasound-assisted extraction (UAE) combined with solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS) for the simultaneous determination of eight different pharmaceuticals and personal care products (PPCPs) (ibuprofen, 2-benzyl-4-chlorophenol, naproxen, triclosan, ketoprofen, diclofenac, bisphenol A and estrone) in river sediment. UAE conditions were optimized involving extraction variables such as extraction solvent, extraction time, sample amount, extraction temperature, pH and salt addition. A 100 mg of sediment was extracted by optimized UAE process using 7 mL deionized water (pH 3) + 1% methanol as solvent, room temperature and 1 min extraction at 70% of amplitude. A 5 mL of supernatant was subsequently extracted by SPME; the extracted analytes were derivatized on fiber in head-space mode with N-methyl-N-(tertbutyldimethylsilyl) trifluoroacetamide and then analyzed by GC-MS. The developed method was evaluated by testing: precision (CV 0.98), recoveries (56-108%), limits of detection (simple and environmentally friendly, and provides straightforward analyses of these trace organic pollutants in sediment samples. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. Halloysite nanotubes as a solid sorbent in ultrasound-assisted dispersive micro solid-phase extraction for the determination of bismuth in water samples using high-resolution continuum source graphite-furnace atomic absorption spectrometry

    Science.gov (United States)

    Krawczyk-Coda, Magdalena

    2017-03-01

    In this research, a simple, accurate, and inexpensive preconcentration procedure was developed for the determination of bismuth in water samples, using high-resolution continuum source graphite furnace atomic absorption spectrometry (HR CS GFAAS). During the preconcentration step, halloysite nanotubes (HNTs) were used as a solid sorbent in ultrasound-assisted dispersive micro solid-phase extraction (USA DMSPE). The influence of the pH of the sample solution, amount of HNTs, and extraction time, as well as of the main parameters of HR CS GFAAS, on absorbance was investigated. The limit of detection was 0.005 μg L- 1. The preconcentration factor achieved for bismuth was 32. The relative standard deviation (RSD) was 4%. The accuracy of this method was validated by analyses of NIST SRM 1643e (Trace elements in water) and TMDA-54.5 (A high level fortified sample for trace elements) certified reference materials. The measured bismuth contents in these certified reference materials were in satisfactory agreement with the certified values according to the t-test for a 95% confidence level. The proposed method has been successfully applied to the determination of bismuth in five different real water samples (seawater, lake water, river water, stream water and rain water).

  7. Trace determination of five triazole fungicide residues in traditional Chinese medicine samples by dispersive solid-phase extraction combined with ultrasound-assisted dispersive liquid-liquid microextraction and UHPLC-MS/MS.

    Science.gov (United States)

    Ma, Shuping; Yuan, Xucan; Zhao, Pengfei; Sun, Hong; Ye, Xiu; Liang, Ning; Zhao, Longshan

    2017-08-01

    A novel and reliable method for determination of five triazole fungicide residues (triadimenol, tebuconazole, diniconazole, flutriafol, and hexaconazol) in traditional Chinese medicine samples was developed using dispersive solid-phase extraction combined with ultrasound-assisted dispersive liquid-liquid microextraction before ultra-high performance liquid chromatography with tandem mass spectrometry. The clean up of the extract was conducted using dispersive solid-phase extraction by directly adding sorbents into the extraction solution, followed by shaking and centrifugation. After that, a mixture of 400 μL trichloromethane (extraction solvent) and 0.5 mL of the above supernatant was injected rapidly into water for the dispersive liquid-liquid microextraction procedure. The factors affecting the extraction efficiency were optimized. Under the optimum conditions, the calibration curves showed good linearity in the range of 2.0-400 (tebuconazole, diniconazole, and hexaconazole) and 4.0-800 ng/g (triadimenol and flutriafol) with the regression coefficients higher than 0.9958. The limit of detection and limit of quantification for the present method were 0.5-1.1 and 1.8-4.0 ng/g, respectively. The recoveries of the target analytes ranged from 80.2 to 103.2%. The proposed method has been successfully applied to the analysis of five triazole fungicides in traditional Chinese medicine samples, and satisfactory results were obtained. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Ultrasound-assisted leaching-dispersive solid-phase extraction followed by liquid-liquid microextraction for the determination of polybrominated diphenyl ethers in sediment samples by gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Fontana, Ariel R; Lana, Nerina B; Martinez, Luis D; Altamirano, Jorgelina C

    2010-06-30

    Ultrasound-assisted leaching-dispersive solid-phase extraction followed by dispersive liquid-liquid microextraction (USAL-DSPE-DLLME) technique has been developed as a new analytical approach for extracting, cleaning up and preconcentrating polybrominated diphenyl ethers (PBDEs) from sediment samples prior gas chromatography-tandem mass spectrometry (GC-MS/MS) analysis. In the first place, PBDEs were leached from sediment samples by using acetone. This extract was cleaned-up by DSPE using activated silica gel as sorbent material. After clean-up, PBDEs were preconcentrated by using DLLME technique. Thus, 1 mL acetone extract (disperser solvent) and 60 microL carbon tetrachloride (extraction solvent) were added to 5 mL ultrapure water and a DLLME technique was applied. Several variables that govern the proposed technique were studied and optimized. Under optimum conditions, the method detection limits (MDLs) of PBDEs calculated as three times the signal-to-noise ratio (S/N) were within the range 0.02-0.06 ng g(-1). The relative standard deviations (RSDs) for five replicates were or =0.9991. Validation of the methodology was carried out by standard addition method at two concentration levels (0.25 and 1 ng g(-1)) and by comparing with a reference Soxhlet technique. Recovery values were > or =80%, which showed a satisfactory robustness of the analytical methodology for determination of low PBDEs concentration in sediment samples. Copyright 2010 Elsevier B.V. All rights reserved.

  9. Comparison, artificial neural network modeling and genetic algorithm optimization of the resinoid and potassium yields from white lady’s bedstraw (Galium mollugo L. by conventional, reflux and ultrasound-assisted aqueous-ethanolic extraction

    Directory of Open Access Journals (Sweden)

    Milić Petar S.

    2013-01-01

    Full Text Available In this work, the yields of resinoid and potassium obtained from aerial parts of white lady’s bedstraw (Galium mollugo L. by maceration, reflux extraction and ultrasound-assisted extraction using aqueous ethanol solutions as solvents. The main goal was to define the influence of the extraction technique and the ethanol concentration on the resinoid and potassium yields. The resinoid and potassium yields were determined by the solvent evaporation from the liquid extracts to constant weight and the AAS emission method, respectively. The dependence of resinoid and potassium yields on the ethanol concentration was described by linear and quadratic polynomial models, respectively. The best potassium extraction selectivity of 0.077 g K/g of dry extract was achieved by maceration at the ethanol concentrations of 10 g/100 g. The artificial neural network (ANN was successfully applied to estimate the resinoid and potassium yields based on the ethanol concentration in the extracting solvent and the time duration for all three extraction techniques employed. The response surface methodology was also used to present the dependence of ANN results on the operating factors. The extraction process was optimized using the ANN model coupled with genetic algorithm. The maximum predicted resinoid and potassium yields of 30.4 and 1.67 g/100 g of dry plant were obtained by the ultrasonic extraction (80 min using the 10 g/100 g aqueous ethanol solution.

  10. Extraction of Dihydroquercetin from Larix gmelinii with Ultrasound-Assisted and Microwave-Assisted Alternant Digestion

    Directory of Open Access Journals (Sweden)

    Yuangang Zu

    2012-07-01

    Full Text Available An ultrasound and microwave assisted alternant extraction method (UMAE was applied for extracting dihydroquercetin (DHQ from Larix gmelinii wood. This investigation was conducted using 60% ethanol as solvent, 1:12 solid to liquid ratio, and 3 h soaking time. The optimum treatment time was ultrasound 40 min, microwave 20 min, respectively, and the extraction was performed once. Under the optimized conditions, satisfactory extraction yield of the target analyte was obtained. Relative to ultrasound-assisted or microwave-assisted method, the proposed approach provides higher extraction yield. The effect of DHQ of different concentrations and synthetic antioxidants on oxidative stability in soy bean oil stored for 20 days at different temperatures (25 °C and 60 °C was compared. DHQ was more effective in restraining soy bean oil oxidation, and a dose-response relationship was observed. The antioxidant activity of DHQ was a little stronger than that of BHA and BHT. Soy bean oil supplemented with 0.08 mg/g DHQ exhibited favorable antioxidant effects and is preferable for effectively avoiding oxidation. The L. gmelinii wood samples before and after extraction were characterized by scanning electron microscopy. The results showed that the UMAE method is a simple and efficient technique for sample preparation.

  11. Optimisation of ultrasound-assisted reverse micelles dispersive liquid-liquid micro-extraction by Box-Behnken design for determination of acetoin in butter followed by high performance liquid chromatography.

    Science.gov (United States)

    Roosta, Mostafa; Ghaedi, Mehrorang; Daneshfar, Ali

    2014-10-15

    A novel approach, ultrasound-assisted reverse micelles dispersive liquid-liquid microextraction (USA-RM-DLLME) followed by high performance liquid chromatography (HPLC) was developed for selective determination of acetoin in butter. The melted butter sample was diluted and homogenised by n-hexane and Triton X-100, respectively. Subsequently, 400μL of distilled water was added and the microextraction was accelerated by 4min sonication. After 8.5min of centrifugation, sedimented phase (surfactant-rich phase) was withdrawn by microsyringe and injected into the HPLC system for analysis. The influence of effective variables was optimised using Box-Behnken design (BBD) combined with desirability function (DF). Under optimised experimental conditions, the calibration graph was linear over the range of 0.6-200mgL(-1). The detection limit of method was 0.2mgL(-1) and coefficient of determination was 0.9992. The relative standard deviations (RSDs) were less than 5% (n=5) while the recoveries were in the range of 93.9-107.8%. Copyright © 2014. Published by Elsevier Ltd.

  12. Ultrasound-assisted surfactant-enhanced emulsification microextraction with solidification of floating organic droplet followed by high performance liquid chromatography for the determination of strobilurin fungicides in fruit juice samples.

    Science.gov (United States)

    Liang, Pei; Liu, Guojiao; Wang, Fang; Wang, Wanting

    2013-05-01

    A novel method, ultrasound-assisted surfactant-enhanced emulsification microextraction with solidification of floating organic droplet (UASEME-SFOD), has been developed for the extraction of four strobilurin fungicides (kresoxim-methyl, picoxystrobin, pyraclostrobin and trifloxystrobin) in fruit juices. In the UASEME-SFOD technique, Tween 80 was used as emulsifier, and 1-undecanol was used as extraction solvent without using any organic dispersive solvent. Several parameters that affect the extraction efficiency, such as the kind and volume of extraction solvent, the type and concentration of the surfactant, extraction time, extraction temperature and salt addition were investigated and optimized. Under the optimum extraction condition, the method yields a linear calibration curve in the concentration range from 5 to 10,000 ng mL(-1) for the targeted analytes with the correlation coefficient ranging from 0.9991 to 0.9998. The enrichment factors were in the range between 95 and 135, and the limits of detection of the method were 2-4 ng mL(-1). The fruit juice samples were successfully analyzed using the proposed method, and the relative recoveries at fortified levels of 50 and 100 ng mL(-1) were in the range of 82.6-97.5%. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Lewis Acidic Ionic Liquids.

    Science.gov (United States)

    Brown, Lucy C; Hogg, James M; Swadźba-Kwaśny, Małgorzata

    2017-08-21

    Until very recently, the term Lewis acidic ionic liquids (ILs) was nearly synonymous with halometallate ILs, with a strong focus on chloroaluminate(III) systems. The first part of this review covers the historical context in which these were developed, speciation of a range of halometallate ionic liquids, attempts to quantify their Lewis acidity, and selected recent applications: in industrial alkylation processes, in supported systems (SILPs/SCILLs) and in inorganic synthesis. In the last decade, interesting alternatives to halometallate ILs have emerged, which can be divided into two sub-sections: (1) liquid coordination complexes (LCCs), still based on halometallate species, but less expensive and more diverse than halometallate ionic liquids, and (2) ILs with main-group Lewis acidic cations. The two following sections cover these new liquid Lewis acids, also highlighting speciation studies, Lewis acidity measurements, and applications.

  14. Functional ionic liquids

    International Nuclear Information System (INIS)

    Baecker, Tobias

    2012-01-01

    In the thesis at hand, new functional ionic liquids were investigated. Main focus was attended to their structure property relations and the structural features leading to a decrease of the melting point. New compounds of the type 1-butyl-3-methylimidazolium tris(N,Ndialkyldithiocarbamato) uranylate with variously substituated dithiocarbamato ligands were synthesized and characterized. Ligands with asymmetrical substitution pattern proved to be most suitable for ionic liquid formation. The single-crystal X-ray structures revealed the interactions in the solid state. Here, the first spectroscopic investigation of the U-S bond in sulfur donated uranyl complexes, up to now only observed in single-crystal X-ray structures, is presented, and the participation of the uranium f-orbitals is shown by theoretical calculations. Electrochemical investigations showed the accessibility of the respective U V O 2 + compounds. As well, ionic liquids with [FeCl 4 ] - and [Cl 3 FeOFeCl 3 ] 2- as anion were synthesized. Both of these anions contain high-spin Fe(III) centres in distorted tetrahedral environment, but exhibit different magnetic behaviour. The tetrachloroferrates show the usual paramagnetism, the m-oxobis(trichloroferrate) exhibits unexpectedly strong antiferromagnetic coupling, as was observed by NMR experiments and susceptibility measurements. To investigate structure-property relations in functionalized ionic liquids, a set of protic, primary alkylammonium and aprotic, quarternary trimethylalkylammonium based ionic liquids was synthesized, and characterized. The length of the alkyl chain was systematically varied, and all compounds were synthesized with and without hydroxyl group, as well as formate and bis(triflyl)amide salts, aiming at getting insight into the influence of the different structure parts on the respective ionic liquid's properties.

  15. Ionic liquid solutions as extractive solvents for value-added compounds from biomass.

    Science.gov (United States)

    Passos, Helena; Freire, Mara G; Coutinho, João A P

    2014-12-01

    In the past few years, the number of studies regarding the application of ionic liquids (ILs) as alternative solvents to extract value-added compounds from biomass has been growing. Based on an extended compilation and analysis of the data hitherto reported, the main objective of this review is to provide an overview on the use of ILs and their mixtures with molecular solvents for the extraction of value-added compounds present in natural sources. The ILs (or IL solutions) investigated as solvents for the extraction of natural compounds, such as alkaloids, flavonoids, terpenoids, lipids, among others, are outlined. The extraction techniques employed, namely solid-liquid extraction, and microwave-assisted and ultrasound-assisted extractions, are emphasized and discussed in terms of extraction yields and purification factors. Furthermore, the evaluation of the IL chemical structure and the optimization of the process conditions (IL concentration, temperature, biomass-solvent ratio, etc.) are critically addressed. Major conclusions on the role of the ILs towards the extraction mechanisms and improved extraction yields are additionally provided. The isolation and recovery procedures of the value-added compounds are ascertained as well as some scattered strategies already reported for the IL solvent recovery and reusability. Finally, a critical analysis on the economic impact versus the extraction performance of IL-based methodologies was also carried out and is here presented and discussed.

  16. Positrons in ionic crystals

    International Nuclear Information System (INIS)

    Pareja, R.

    1988-01-01

    Positron annihilation experiments in ionic crystals are reviewed and their results are arranged. A discussion about the positron states in these materials is made in the light of these results and the different proposed models. The positronium in alkali halides is specially considered. (Author)

  17. Ionic smoke detectors

    CERN Document Server

    2002-01-01

    Ionic smoke detectors are products incorporating radioactive material. This article summarises the process for their commercialization and marketing, and how the activity is controlled, according to regulations establishing strict design and production requisites to guarantee the absence of radiological risk associated both with their use and their final handling as conventional waste. (Author)

  18. Ultrasound-assisted dispersive magnetic solid phase extraction based on amino-functionalized Fe3O4 adsorbent for recovery of clomipramine from human plasma and its determination by high performance liquid chromatography: Optimization by experimental design.

    Science.gov (United States)

    Hamidi, Fatemeh; Hadjmohammadi, Mohammad Reza; Aghaie, Ali B G

    2017-09-15

    The applicability of Amino-functionalized Fe 3 O 4 nanoparticles (NPs) as an effective adsorbent was developed for the extraction and determination of clomipramine (CLP) in plasma sample by ultrasound-assisted dispersive magnetic solid phase extraction (UADM-SPE) and high-performance liquid chromatography-ultraviolet (HPLC-UV) detection. Fabrication of the Fe 3 O 4 @SiO 2 -NH 2 magnetic nanoparticles confirmed by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The effect of different extraction parameters (i.e. pH of the sample solution, the amount of magnetic nanoparticles (MNPs), sample volume, temperature and sonication time) on the extraction recovery of CLP were investigated by response surface methodology through central composite design (CCD). The optimum condition is obtained when the affecting parameters are set to: pH of the sample solution=9, the amount of MNPs=37mg, sample volume=23mL, 25°C temperature and sonication time=1min. Under the optimum condition, extraction recovery was 90.6% with relative standard deviation of 3.5%, and enrichment factor of 117. The linear range for determination of CLP was 0.017-0.70mgL -1 with a determination coefficient (R 2 ) of 0.999. Limit of detection (LOD) and limit of quantification (LOQ) were 0.005 and 0.0167mgL -1 , respectively. The established UADM-SPE-HPLC-UV method was rapid, simple and efficient for determination of CLP in human plasma samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Deep eutectic solvent-based ultrasound-assisted dispersive liquid-liquid microextraction coupled with high-performance liquid chromatography for the determination of ultraviolet filters in water samples.

    Science.gov (United States)

    Wang, Huazi; Hu, Lu; Liu, Xinya; Yin, Shujun; Lu, Runhua; Zhang, Sanbing; Zhou, Wenfeng; Gao, Haixiang

    2017-09-22

    In the present study, a simple and rapid sample preparation method designated ultrasound-assisted dispersive liquid-liquid microextraction based on a deep eutectic solvent (DES) followed by high-performance liquid chromatography with ultraviolet (UV) detection (HPLC-UVD) was developed for the extraction and determination of UV filters from water samples. The model analytes were 2,4-dihydroxybenzophenone (BP-1), benzophenone (BP) and 2-hydroxy-4-methoxybenzophenone (BP-3). The hydrophobic DES was prepared by mixing trioctylmethylammonium chloride (TAC) and decanoic acid (DecA). Various influencing factors (selection of the extractant, amount of DES, ultrasound duration, salt addition, sample volume, sample pH, centrifuge rate and duration) on UV filter recovery were systematically investigated. Under optimal conditions, the proposed method provided good recoveries in the range of 90.2-103.5% and relative standard deviations (inter-day and intra-day precision, n=5) below 5.9%. The enrichment factors for the analytes ranged from 67 to 76. The limits of detection varied from 0.15 to 0.30ngmL -1 , depending on the analytes. The linearities were between 0.5 and 500ngmL -1 for BP-1 and BP and between 1 and 500ngmL -1 for BP-3, with coefficients of determination greater than 0.99. Finally, the proposed method was applied to the determination of UV filters in swimming pool and river water samples, and acceptable relative recoveries ranging from 82.1 to 106.5% were obtained. Copyright © 2017. Published by Elsevier B.V.

  20. Effect of ultrasound-assisted crystallization in the diastereomeric salt resolution of tetramisole enantiomers in ternary system with O,O'-dibenzoyl-(2R,3R)-tartaric acid.

    Science.gov (United States)

    Szeleczky, Zsolt; Kis-Mihály, Erzsébet; Semsey, Sándor; Pataki, Hajnalka; Bagi, Péter; Pálovics, Emese; Marosi, György; Pokol, György; Fogassy, Elemér; Madarász, János

    2016-09-01

    The diastereomeric salt resolution of racemic tetramisole was studied using ultrasound irradiation. We examined the effect of power and duration of ultrasonic irradiation on the properties of the crystalline phase formed by ultrasound-assisted crystallization and the result of the whole optical resolution. The results were compared with reference experiment without using ultrasound. The US time (5-30min) caused higher enantiomeric excess. Although yield was lower continuously high resolving efficiency could have been reached through ultrasound. We had the best results with 4.3W ultrasound power when resolvability was even higher than the best of reference. Furthermore, we accomplished a deep and thorough examination of the salts that possibly could form in this resolution. One of the four diastereomeric salts, which have been identified by powder X-ray diffraction, FTIR-spectroscopy, and differential scanning calorimetry (DSC) in the ternary system of the two tetramisole enantiomers and the resolving agent, namely the bis[(S)-tetramisole]-dibenzoyl-(R,R)-tartrate salt have been proven the key compound in the resolution process, and presented the highest melting point of 166°C (dec.) among the four salts. The originally expected diastereomeric bitartrate salts with 1:1M base:acid ratio [(S)-tetramisole-dibenzoyl-(R,R)-hydrogen-tartrate salt and (R)-tetramisole-dibenzoyl-(R,R)-hydrogen-tartrate salt] and their 'racemic' co-crystal [(RS)-tetramisole-dibenzoyl-(R,R)-hydrogen-tartrate salt] showed somewhat lower melting points (152, 145, and 150°C, respectively) and their crystallization was also prevented by application of ultrasound. Based on the melting points and enthalpies of fusion measured by DSC, all the binary and ternary phase diagrams have been newly established and calculated in the system with help of classical modelling equations of liquidus curves. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Analysis of amino acid and monoamine neurotransmitters and their metabolites in rat urine of Alzheimer's disease using in situ ultrasound-assisted derivatization dispersive liquid-liquid microextraction with UHPLC-MS/MS.

    Science.gov (United States)

    Zhao, Xian-En; He, Yongrui; Li, Meng; Chen, Guang; Wei, Na; Wang, Xiao; Sun, Jing; Zhu, Shuyun; You, Jinmao

    2017-02-20

    Neurotransmitters (NTs) may play an important role in neurodegenerative disorders such as Alzheimer's disease (AD). In order to investigate the potential links, a new simple, fast, accurate and sensitive analytical method, based on in situ ultrasound-assisted derivatization dispersive liquid-liquid microextraction (in situ UA-DDLLME) coupled with ultra high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS), has been developed and validated. The quantitation of amino acid neurotransmitters (AANTs) and monoamine neurotransmitters (MANTs) in urine of AD rats were performed in this work. The in situ UA-DDLLME procedure involved the rapid injection of the mixture of low toxic 4-bromoanisole (extractant) and acetonitrile (dispersant), which containing the new designed and synthesized 4'-carbonyl chloride rosamine (CCR) as derivatization reagent, into the aqueous phase of real sample and buffer. Under the selected conditions, the derivatization and microextraction of analytes were simultaneously completed within 1min. Good linearity for each analyte (R>0.992) was observed with low limit of detections (LODs, S/N>3). Moreover, the proposed method was compared with direct detection or other reported methods, and the results showed that low matrix effects and good recoveries results were obtained in this work. Taken together, in situ UA-DDLLME coupled with UHPLC-MS/MS analysis was demonstrated to be a good method for sensitive, accurate and simultaneous monitoring of AANTs and MANTs. This method would be expected to be highly useful in AD diseases' clinical diagnostics and may have potential value in monitoring the efficacy of treatment. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Rapid ultrasound-assisted magnetic microextraction of gallic acid from urine, plasma and water samples by HKUST-1-MOF-Fe3O4-GA-MIP-NPs: UV-vis detection and optimization study.

    Science.gov (United States)

    Asfaram, Arash; Ghaedi, Mehrorang; Dashtian, Kheibar

    2017-01-01

    Magnetite (Fe 3 O 4 nanoparticles (NPs)) HKUST-1 metal organic framework (MOF) composite as a support was used for surface imprinting of gallic acid imprinted polymer (HKUST-1-MOF-Fe 3 O 4 -GA-MIP) using vinyltrimethoxysilane (VTMOS) as the cross-linker. Subsequently, HKUST-1-MOF-Fe 3 O 4 -NPs-GA-MIP characterized by FT-IR, XRD and FE-SEM analysis and applied for fast and selective and sensitive ultrasound assisted dispersive magnetic solid phase microextraction of gallic acid (GA) by UV-Vis (UA-DMSPME-UV-Vis) detection method. Plackett-Burman design (PBD) and central composite design (CCD) according to desirability function (DF) indicate the significant variables among the extraction factors vortex (mixing) time (min), sonication time (min), temperature (°C), eluent volume (L), pH and HKUST-1-MOF-Fe 3 O 4 -NPs-GA-MIP mass (mg) and their contribution on the response. Optimum conditions and values correspond to pH, HKUST-1-MOF-Fe 3 O 4 -NPs-GA-MIP mass, sonication time and the eluent volume were set as follow 3.0, 1.6mg, 4.0min and 180μL, respectively. The average recovery (ER%) of GA was 98.13% with desirability of 0.997, while the present method has best operational performance like wide linear range 8-6000ngmL -1 with a Limit of detection (LOD) of 1.377ngmL -1 , limit of quantification (LOQ) 4.591ngmL -1 and precision (<3.50% RSD). The recovery of GA in urine, human plasma and water samples within the range of 92.3-100.6% that strongly support high applicability of present method for real samples analysis, which candidate this method as promise for further application. Copyright © 2016. Published by Elsevier B.V.

  3. Rapid determination of triclosan in personal care products using new in-tube based ultrasound-assisted salt-induced liquid-liquid microextraction coupled with high performance liquid chromatography-ultraviolet detection.

    Science.gov (United States)

    Chen, Ming-Jen; Liu, Ya-Ting; Lin, Chiao-Wen; Ponnusamy, Vinoth Kumar; Jen, Jen-Fon

    2013-03-12

    This paper describes the development of a novel, simple and efficient in-tube based ultrasound-assisted salt-induced liquid-liquid microextraction (IT-USA-SI-LLME) technique for the rapid determination of triclosan (TCS) in personal care products by high performance liquid chromatography-ultraviolet (HPLC-UV) detection. IT-USA-SI-LLME method is based on the rapid phase separation of water-miscible organic solvent from the aqueous phase in the presence of high concentration of salt (salting-out phenomena) under ultrasonication. In the present work, an indigenously fabricated home-made glass extraction device (8-mL glass tube inbuilt with a self-scaled capillary tip) was utilized as the phase separation device for USA-SI-LLME. After the extraction, the upper extractant layer was narrowed into the self-scaled capillary tip by pushing the plunger plug; thus, the collection and measurement of the upper organic solvent layer was simple and convenient. The effects of various parameters on the extraction efficiency were thoroughly evaluated and optimized. Under optimal conditions, detection was linear in the concentration range of 0.4-100ngmL(-1) with correlation coefficient of 0.9968. The limit of detection was 0.09ngmL(-1) and the relative standard deviations ranged between 0.8 and 5.3% (n=5). The applicability of the developed method was demonstrated for the analysis of TCS in different commercial personal care products and the relative recoveries ranged from 90.4 to 98.5%. The present method was proven to be a simple, sensitive, less organic solvent consuming, inexpensive and rapid procedure for analysis of TCS in a variety of commercially available personal care products or cosmetic preparations. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Evaluation of ultrasound-assisted extraction as sample pre-treatment for quantitative determination of rare earth elements in marine biological tissues by inductively coupled plasma-mass spectrometry

    International Nuclear Information System (INIS)

    Costas, M.; Lavilla, I.; Gil, S.; Pena, F.; Calle, I.; Cabaleiro, N. de la; Bendicho, C.

    2010-01-01

    In this work, the determination of rare earth elements (REEs), i.e. Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu in marine biological tissues by inductively coupled-mass spectrometry (ICP-MS) after a sample preparation method based on ultrasound-assisted extraction (UAE) is described. The suitability of the extracts for ICP-MS measurements was evaluated. For that, studies were focused on the following issues: (i) use of clean up of extracts with a C18 cartridge for non-polar solid phase extraction; (ii) use of different internal standards; (iii) signal drift caused by changes in the nebulization efficiency and salt deposition on the cones during the analysis. The signal drift produced by direct introduction of biological extracts in the instrument was evaluated using a calibration verification standard for bracketing (standard-sample bracketing, SSB) and cumulative sum (CUSUM) control charts. Parameters influencing extraction such as extractant composition, mass-to-volume ratio, particle size, sonication time and sonication amplitude were optimized. Diluted single acids (HNO 3 and HCl) and mixtures (HNO 3 + HCl) were evaluated for improving the extraction efficiency. Quantitative recoveries for REEs were achieved using 5 mL of 3% (v/v) HNO 3 + 2% (v/v) HCl, particle size <200 μm, 3 min of sonication time and 50% of sonication amplitude. Precision, expressed as relative standard deviation from three independent extractions, ranged from 0.1 to 8%. In general, LODs were improved by a factor of 5 in comparison with those obtained after microwave-assisted digestion (MAD). The accuracy of the method was evaluated using the CRM BCR-668 (mussel tissue). Different seafood samples of common consumption were analyzed by ICP-MS after UAE and MAD.

  5. Isotherms and kinetic study of ultrasound-assisted adsorption of malachite green and Pb2+ ions from aqueous samples by copper sulfide nanorods loaded on activated carbon: Experimental design optimization.

    Science.gov (United States)

    Sharifpour, Ebrahim; Khafri, Hossein Zare; Ghaedi, Mehrorang; Asfaram, Arash; Jannesar, Ramin

    2018-01-01

    Copper sulfide nanorods loaded on activated carbon (CuS-NRs-AC) was synthesized and used for simultaneous ultrasound-assisted adsorption of malachite green (MG) and Pb 2+ ions from aqueous solution. Following characterization of CuS-NRs-AC were investigated by SEM, EDX, TEM and XRD, the effects of pH (2.0-10), amount of adsorbent (0.003-0.011g), MG concentration (5-25mgL -1 ), Pb 2+ concentration (3-15mgL -1 ) and sonication time (1.5-7.5min) and their interactions on responses were investigated by central composite design (CCD) and response surface methodology. According to desirability function on the Design Expert optimum removal (99.4%±1.0 for MG and 68.3±1.8 for Pb 2+ ions) was obtained at pH 6.0, 0.009g CuS-NRs-AC, 6.0min mixing by sonication and 15 and 6mgL -1 for MG and Pb 2+ ions, respectively. High determination coefficient (R 2 >0.995), Pred-R 2 -value (>0.920) and Adju-R 2 -value (>0.985) all are good indication of best agreement between the experimental and design modelling. The adsorption kinetics follows the pseudo-second order model and adsorption isotherm follows the Langmuir model with maximum adsorption capacity of 145.98 and 47.892mgg -1 for MG and Pb 2+ ions, respectively. This adsorbent over short contact time is good choice for simultaneous removal of large content of both MG and Pb 2+ ions from wastewater sample. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Determination of fluorine in herbs and water samples by molecular absorption spectrometry after preconcentration on nano-TiO2 using ultrasound-assisted dispersive micro solid phase extraction.

    Science.gov (United States)

    Krawczyk-Coda, Magdalena; Stanisz, Ewa

    2017-11-01

    This work presents ultrasound-assisted dispersive micro solid phase extraction (USA DMSPE) for preconcentration of fluorine (F) in water and herb samples. TiO 2 nanoparticles (NPs) were used as an adsorbent. The determination with slurry sampling was performed via molecular absorption of calcium monofluoride (CaF) at 606.440 nm using a high-resolution continuum source electrothermal absorption spectrometry (HR-CS ET MAS). Several factors influencing the efficiency of the preconcentration technique, such as the amount of TiO 2 , pH of sample solution, ultrasonication and centrifugation time and TiO 2 slurry solution preparation before injection to HR-CS ET MAS, were investigated in detail. The conditions of detection step (wavelength, calcium amount, pyrolysis and molecule-forming temperatures) were also studied. After extraction, adsorbent with the analyte was mixed with 200 μL of H 2 O to prepare a slurry solution. The concentration limit of detection was 0.13 ng mL -1 . The achieved preconcentration factor was 7. The relative standard deviations (RSDs, %) for F in real samples were 3-15%. The accuracy of this method was evaluated by analyses of certified reference materials after spiking: INCT-MPH-2 (Mixed Polish Herbs), INCT-SBF-4 (Soya Bean Flour), ERM-CAO11b (Hard Drinking Water) and TMDA-54.5 (Lake Ontario Water). The measured F contents in reference materials were in satisfactory agreement with the added amounts, and the recoveries were found to be 97-109%. Under the developed extraction conditions, the proposed method has been successfully applied for the determination of F in real water samples (lake, sea, tap water) and herbs.

  7. Optimization of ultrasound-assisted extraction of phenolic compounds from grapefruit (Citrus paradisi Macf.) leaves via D-optimal design and artificial neural network design with categorical and quantitative variables.

    Science.gov (United States)

    Ciğeroğlu, Zeynep; Aras, Ömür; Pinto, Carlos A; Bayramoglu, Mahmut; Kırbaşlar, Ş İsmail; Lorenzo, José M; Barba, Francisco J; Saraiva, Jorge A; Şahin, Selin

    2018-03-06

    The extraction of phenolic compounds from grapefruit leaves assisted by ultrasound-assisted extraction (UAE) was optimized using response surface methodology (RSM) by means of D-optimal experimental design and artificial neural network (ANN). For this purpose, five numerical factors were selected: ethanol concentration (0-50%), extraction time (15-60 min), extraction temperature (25-50 °C), solid:liquid ratio (50-100 g L -1 ) and calorimetric energy density of ultrasound (0.25-0.50 kW L -1 ), whereas ultrasound probe horn diameter (13 or 19 mm) was chosen as categorical factor. The optimized experimental conditions yielded by RSM were: 10.80% for ethanol concentration; 58.52 min for extraction time; 30.37 °C for extraction temperature; 52.33 g L -1 for solid:liquid ratio; 0.457 kW L -1 for ultrasonic power density, with thick probe type. Under these conditions total phenolics content was found to be 19.04 mg gallic acid equivalents g -1 dried leaf. The same dataset was used to train multilayer feed-forward networks using different approaches via MATLAB, with ANN exhibiting superior performance to RSM (differences included categorical factor in one model and higher regression coefficients), while close values were obtained for the extraction variables under study, except for ethanol concentration and extraction time. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

  8. Simultaneous multi-mycotoxin determination in nutmeg by ultrasound-assisted solid-liquid extraction and immunoaffinity column clean-up coupled with liquid chromatography and on-line post-column photochemical derivatization-fluorescence detection.

    Science.gov (United States)

    Kong, Wei-Jun; Liu, Shu-Yu; Qiu, Feng; Xiao, Xiao-He; Yang, Mei-Hua

    2013-05-07

    A simple and sensitive analytical method based on ultrasound-assisted solid-liquid extraction and immunoaffinity column clean-up coupled with high performance liquid chromatography and on-line post-column photochemical derivatization-fluorescence detection (USLE-IAC-HPLC-PCD-FLD) has been developed for simultaneous multi-mycotoxin determination of aflatoxins B1, B2, G1, G2 (AFB1, AFB2, AFG1, AFG2) and ochratoxin A (OTA) in 13 edible and medicinal nutmeg samples marketed in China. AFs and OTA were extracted from nutmeg samples by ultrasonication using a methanol : water (80 : 20, v/v) solution, followed by an IAC clean-up step. Different USL extraction conditions, pre-processing ways for nutmeg sample and clean-up columns for mycotoxins, as well as HPLC-PCD-FLD parameters (mobile phase, column temperature, elution procedure, excitation and emission wavelengths) were optimized. This method, which was appraised for analyzing nutmeg samples, showed satisfactory results with reference to limits of detection (LODs) (from 0.02 to 0.25 μg kg(-1)), limits of quantification (LOQs) (from 0.06 to 0.8 μg kg(-1)), linear ranges (up to 30 ng mL(-1) for AFB1, AFG1 and OTA and 9 ng mL(-1) for AFB2 and AFG2), intra- and inter-day variability (all application of developed method in nutmeg samples have elucidated that four samples were detected with contamination of AFs and one with OTA. AFB1 was the most frequently found mycotoxin in 30.8% of nutmeg samples at contamination levels of 0.73-16.31 μg kg(-1). At least two different mycotoxins were co-occurred in three samples, and three AFs were simultaneously detected in one sample.

  9. Non-haloaluminate room-temperature ionic liquids in electrochemistry--a review.

    Science.gov (United States)

    Buzzeo, Marisa C; Evans, Russell G; Compton, Richard G

    2004-08-20

    Some twenty-five years after they first came to prominence as alternative electrochemical solvents, room temperature ionic liquids (RTILs) are currently being employed across an increasingly wide range of chemical fields. This review examines the current state of ionic liquid-based electrochemistry, with particular focus on the work of the last decade. Being composed entirely of ions and possesing wide electrochemical windows (often in excess of 5 volts), it is not difficult to see why these compounds are seen by electrochemists as attractive potential solvents. Accordingly, an examination of the pertinent properties of ionic liquids is presented, followed by an assessment of their application to date across the various electrochemical disciplines, concluding with an outlook viewing current problems and directions.

  10. Fabrication of Greener Membranes from Ionic Liquid Solutions

    KAUST Repository

    Kim, DooLi

    2017-06-01

    Membrane technology plays a crucial role in different separation processes such as biotechnology, pharmaceutical, and food industries, drinking water supply, and wastewater treatment. However, there is a growing concern that solvents commonly used for membrane fabrication, such as dimethylformamide (DMF), dimethylacetamide (DMAc), and 1-methyl-2-pyrrolidone (NMP), are toxic to the environment and human health. To explore the possibility of substituting these toxic solvents by less toxic or safer solvents, polymers commonly used for membrane fabrication, such as polyacrylonitrile (PAN), cellulose acetate (CA), polyethersulfone (PES), and poly(ether imide sulfone) (EXTEMTM), were dissolved in ionic liquids. Flat sheet and hollow fiber membranes were then fabricated. The thermodynamics of the polymer solutions, the kinetics of phase inversion and other factors, which resulted in significant differences in the membrane structure, compared to those of membranes fabricated from more toxic solvents, were investigated. Higher water permeance with smaller pores, unique and uniform morphologies, and narrower pore size distribution, were observed in the ionic liquid-based membranes. Furthermore, comparable performance on separation of peptides and proteins with various molecular weights was achieved with the membranes fabricated from ionic liquid solutions. In summary, we propose less hazardous polymer solutions to the environment, which can be used for the membrane fabrication with better performance and more regular morphology.

  11. Nanoscale Ionic Materials

    KAUST Repository

    Rodriguez, Robert; Herrera, Rafael; Archer, Lynden A.; Giannelis, Emmanuel P.

    2008-01-01

    Polymer nanocomposites (nanoparticles dispersed in a polymer matrix) have been the subject of intense research for almost two decades in both academic and industrial settings. This interest has been fueled by the ability of nanocomposites to not only improve the performance of polymers, but also by their ability to introduce new properties. Yet, there are still challenges that polymer nanocomposites must overcome to reach their full potential. In this Research News article we discuss a new class of hybrids termed nanoparticle ionic materials (NIMS). NIMS are organic-inorganic hybrid materials comprising a nanoparticle core functionalized with a covalently tethered ionic corona. They are facilely engineered to display flow properties that span the range from glassy solids to free flowing liquids. These new systems have unique properties that can overcome some of the challenges facing nanocomosite materials. © 2008 WILEY-VCH Verlag GmbH & Co. KGaA.

  12. Super ionic conductive glass

    Science.gov (United States)

    Susman, S.; Volin, K.J.

    Described is an ionically conducting glass for use as a solid electrolyte in a power or secondary cell containing an alkali metal-containing anode and a cathode separated by an alkali metal ion conducting glass having an ionic transference number of unity and the general formula: A/sub 1 + x/D/sub 2-x/3/Si/sub x/P/sub 3 - x/O/sub 12 - 2x/3/, wherein A is a network modifier for the glass and is an alkali metal of the anode, D is an intermediate for the glass and is selected from the class consisting of Zr, Ti, Ge, Al, Sb, Be, and Zn and X is in the range of from 2.25 to 3.0. Of the alkali metals, Na and Li are preferred and of the intermediate, Zr, Ti and Ge are preferred.

  13. Ionic liquid marbles.

    Science.gov (United States)

    Gao, Lichao; McCarthy, Thomas J

    2007-10-09

    Liquid marbles have been reported during this decade and have been argued to be potentially useful for microfluidic and lab-on-a-chip applications. The liquid marbles described to date have been composed of either water or glycerol as the liquid and hydrophobized lycopodium or silica as the stabilizing particles. Both of these components are potentially reactive and do not permit the use of organic chemistry; the liquids are volatile. We report the use of perfluoroalkyl particles (oligomeric (OTFE) and polymeric (PTFE) tetrafluoroethylene, which are unreactive) to support/stabilize a range of ionic liquid marbles. Ionic liquids are not volatile and have been demonstrated to be versatile solvents for chemical transformations. Water marbles prepared with OTFE are much more robust than those prepared with hydrophobized lycopodium or silica.

  14. Nanoscale Ionic Materials

    KAUST Repository

    Rodriguez, Robert

    2008-11-18

    Polymer nanocomposites (nanoparticles dispersed in a polymer matrix) have been the subject of intense research for almost two decades in both academic and industrial settings. This interest has been fueled by the ability of nanocomposites to not only improve the performance of polymers, but also by their ability to introduce new properties. Yet, there are still challenges that polymer nanocomposites must overcome to reach their full potential. In this Research News article we discuss a new class of hybrids termed nanoparticle ionic materials (NIMS). NIMS are organic-inorganic hybrid materials comprising a nanoparticle core functionalized with a covalently tethered ionic corona. They are facilely engineered to display flow properties that span the range from glassy solids to free flowing liquids. These new systems have unique properties that can overcome some of the challenges facing nanocomosite materials. © 2008 WILEY-VCH Verlag GmbH & Co. KGaA.

  15. POSS Ionic Liquid.

    Science.gov (United States)

    Tanaka, Kazuo; Ishiguro, Fumiyasu; Chujo, Yoshiki

    2010-12-22

    We report the synthesis of a stable room-temperature ionic liquid consisting of an octacarboxy polyhedral oligomeric silsesquioxane (POSS) anion and an imidazolium cation. The introduction of the POSS moiety enhances the thermal stability and reduces the melting temperature. From an evaluation of the thermodynamic parameters during the melting, it was found that the rigidity and cubic structure of POSS can contribute to the enhancement of these thermal properties.

  16. Thermodynamic estimation: Ionic materials

    International Nuclear Information System (INIS)

    Glasser, Leslie

    2013-01-01

    Thermodynamics establishes equilibrium relations among thermodynamic parameters (“properties”) and delineates the effects of variation of the thermodynamic functions (typically temperature and pressure) on those parameters. However, classical thermodynamics does not provide values for the necessary thermodynamic properties, which must be established by extra-thermodynamic means such as experiment, theoretical calculation, or empirical estimation. While many values may be found in the numerous collected tables in the literature, these are necessarily incomplete because either the experimental measurements have not been made or the materials may be hypothetical. The current paper presents a number of simple and relible estimation methods for thermodynamic properties, principally for ionic materials. The results may also be used as a check for obvious errors in published values. The estimation methods described are typically based on addition of properties of individual ions, or sums of properties of neutral ion groups (such as “double” salts, in the Simple Salt Approximation), or based upon correlations such as with formula unit volumes (Volume-Based Thermodynamics). - Graphical abstract: Thermodynamic properties of ionic materials may be readily estimated by summation of the properties of individual ions, by summation of the properties of ‘double salts’, and by correlation with formula volume. Such estimates may fill gaps in the literature, and may also be used as checks of published values. This simplicity arises from exploitation of the fact that repulsive energy terms are of short range and very similar across materials, while coulombic interactions provide a very large component of the attractive energy in ionic systems. Display Omitted - Highlights: • Estimation methods for thermodynamic properties of ionic materials are introduced. • Methods are based on summation of single ions, multiple salts, and correlations. • Heat capacity, entropy

  17. Course on Ionic Channels

    CERN Document Server

    1986-01-01

    This book is based on a series of lectures for a course on ionic channels held in Santiago, Chile, on November 17-20, 1984. It is intended as a tutorial guide on the properties, function, modulation, and reconstitution of ionic channels, and it should be accessible to graduate students taking their first steps in this field. In the presentation there has been a deliberate emphasis on the spe­ cific methodologies used toward the understanding of the workings and function of channels. Thus, in the first section, we learn to "read" single­ channel records: how to interpret them in the theoretical frame of kinetic models, which information can be extracted from gating currents in re­ lation to the closing and opening processes, and how ion transport through an open channel can be explained in terms of fluctuating energy barriers. The importance of assessing unequivocally the origin and purity of mem­ brane preparations and the use of membrane vesicles and optical tech­ niques in the stUGY of ionic channels a...

  18. Review of available scientific and technical evidence regarding liquid-based cytology

    Directory of Open Access Journals (Sweden)

    Alberto Frutos Pérez-Surio

    2017-06-01

    Full Text Available Introduction. Cervical cancer can be prevented by early diagnosis and treatment of patients with abnormal results, thus decreasing their incidence and mortality. In contrast to conventional techniques (Papanicolau, diagnostic techniques have been developed based on the preservation of the sample in a stabilizing solution (liquid-based cytology. The different methods of liquid-based cytology used in the screening of cervical cancer against the Papanicolau technique are evaluated. Material and methods. A systematic review of the literature has been performed (2010-2015. The search was developed by including MeSH terms as cervical intraepithelial neoplasia and papilloma virus infection in the MedLine, Embase, Cochrane Library, CRD, LILACS and IBECS databases. Inclusion criteria were adult women screened for cervical cancer using liquid-based cytology techniques, compared with conventional methods. Results. 464 references were found related to the reliability-precision of the test, of which 13 were included in the report. A health technology assessment report was conducted in 2013 by the Agency for Health Technology Assessment of Andalusia (AETSA. The quality of the studies was moderate and moderate-low. AETSA found studies that included more than 700,000 women between 14 and 90 years old, who were screened by liquid-based cytology, compared to the conventional one. Studies have shown that liquid-based cytology techniques reduce the percentage of unsatisfactory samples compared to conventional ones. The analysis of detection of cellular abnormalities and diagnostic validity indexes showed significant differences when comparing both methods. Conclusions. The studies analyzed presented methodological limitations. Hence, the results should be interpreted with caution. Liquid-based cytology did not present greater diagnostic capacity than conventional methods, but it reduced, with statistically significant results, the number of samples unsatisfactory

  19. Selective separation of uranium from nuclear waste solution by bis (2,4,4-trimethylpentyl phosphinic) acid in ionic liquid and molecular diluents: a comparative study

    International Nuclear Information System (INIS)

    Singh, Manpreet; Sengupta, Arijit; Murali, M.S.; Adya, V.C.; Kadam, R.M.

    2016-01-01

    Room temperature ionic liquid has been world-wide considered as the potential 'green' alternatives to the molecular diluents. A comparative study was carried out for studying selective separation of uranium from radioactive waste solution using Bis(2,4,4-trimethylpentyl phosphinic) acid in molecular diluent (xylene) and ionic liquid (C 8 mimNTf 2 ). For ionic liquid based system, the extraction kinetics was found to be slower compared to the molecular diluents. This was attributed to the higher viscosity of ionic liquid. In ionic liquid the extraction occurs with the predominance of 'ion exchange' mechanism through (UO 2 (NO 3 ). 2L) + species, while for xylene based system 'solvation' mechanism predominates at higher feed acidity. The extraction process in ionic liquid was found to be thermodynamically more favoured than in xylene. The nature of the extracted species was found to be different in ionic liquid and xylene as obtained from difference in luminescence emission profiles and lifetime of the extracted complex. Ionic liquid based system was found to be radiolytically more stable than the molecular diluents based solvent system. Na 2 CO 3 solution was found to back extract the uranyl ion almost quantitatively (99.9 %) from the loaded organic phase but overall stripping from ionic liquid phase is comparatively poorer than that of xylene phase. The processing of Simulated High Level Waste (SHLW) of Pressurized Heavy Water Reactor (PHWR) or Research Reactor (RR) origin revealed that bis(2,4,4-trimethylpentyl phosphinic) acid can effectively be used for the preferential extraction of U with better selectivity for ionic liquid phase. But the ion exchange mechanism is one of the disadvantages for its plant scale application. (author)

  20. Flavonoids in Different Parts of Lysimachia clethroides Duby Extracted by Ionic Liquid: Analysis by HPLC and Antioxidant Activity Assay

    Directory of Open Access Journals (Sweden)

    Jin-feng Wei

    2017-01-01

    Full Text Available To establish methods for simultaneous determination of isoquercitrin, astragalin in leaves, quercetin, and kaempferol in flowers of Lysimachia clethroides Duby, respectively, the methods were ultrasound-assisted extraction combined with RP-HPLC, and ionic liquid was used as the extraction solvent. Meanwhile, the antioxidant activity of the different extracts of L. clethroides was evaluated. Purospher STAR RP-C18 column (4.6 mm × 250 mm, 5 μm was used for analysis. The flow rate was 0.6 mL·min−1, and the column temperature was 25°C. The detection wavelength was 360 nm. The mobile phases a and b consisted of acetonitrile-0.4% phosphoric acid (18 : 82, v/v, methanol (A, and 0.4% phosphoric acid (B, respectively. Linear ranges were 0.068~1.64, 0.060~1.44, 0.0080~0.19, and 0.0077~0.18 μg for isoquercitrin, astragalin, quercetin, and kaempferol, respectively. The average recoveries of the four constituents were 99.17%, 98.39%, 100.68%, and 98.81%, respectively. The antioxidant activity of the extracts was detected by DPPH, ABTS, and FRAP. Under the optimized conditions, all the test solutions showed a certain antioxidant activity and the ionic liquid extracts were better than that of extract of methanol. Ionic liquid used as the extraction solvent had the potential to extract active ingredients efficiently from L. clethroides, and this method improved the antioxidant activity with accurate and reliable results.

  1. Ultrasound-assisted vapor generation of mercury

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Anderson S.; Vieira, Mariana A. [Universidade Federal de Santa Catarina, Departamento de Quimica, Florianopolis, SC (Brazil); Willie, Scott; Sturgeon, Ralph E. [National Research Council Canada, Institute for National Measurement Standards, Ottawa, ON (Canada)

    2007-06-15

    Cold vapor generation arising from reduction of both Hg{sup 2+} and CH{sub 3}Hg{sup +} occurs using ultrasonic (US) fields of sufficient density to achieve both localized heating as well as radical-based attack in solutions of formic and acetic acids and tetramethylammonium hydroxide (TMAH). A batch sonoreactor utilizing an ultrasonic probe as an energy source and a flow through system based on a US bath were optimized for this purpose. Reduction of CH{sub 3}Hg{sup +} to Hg{sup 0} occurs only at relatively high US field density (>10 W cm{sup -3} of sample solution) and is thus not observed when a conventional US bath is used for cold vapor generation. Speciation of mercury is thus possible by altering the power density during the measurement process. Thermal reduction of Hg{sup 2+} is efficient in formic acid and TMAH at 70 C and occurs in the absence of the US field. Room temperature studies with the batch sonoreactor reveal a slow reduction process, producing temporally broad signals having an efficiency of approximately 68% of that arising from use of a conventional SnCl{sub 2} reduction system. Molecular species of mercury are generated at high concentrations of formic and acetic acid. Factors affecting the generation of Hg{sup 0} were optimized and the batch sonoreactor used for the determination of total mercury in SLRS-4 river water reference material. (orig.)

  2. Ultrasound-assisted vapor generation of mercury.

    Science.gov (United States)

    Ribeiro, Anderson S; Vieira, Mariana A; Willie, Scott; Sturgeon, Ralph E

    2007-06-01

    Cold vapor generation arising from reduction of both Hg(2+) and CH(3)Hg(+) occurs using ultrasonic (US) fields of sufficient density to achieve both localized heating as well as radical-based attack in solutions of formic and acetic acids and tetramethylammonium hydroxide (TMAH). A batch sonoreactor utilizing an ultrasonic probe as an energy source and a flow through system based on a US bath were optimized for this purpose. Reduction of CH(3)Hg(+) to Hg(0) occurs only at relatively high US field density (>10 W cm(-3) of sample solution) and is thus not observed when a conventional US bath is used for cold vapor generation. Speciation of mercury is thus possible by altering the power density during the measurement process. Thermal reduction of Hg(2+) is efficient in formic acid and TMAH at 70 degrees C and occurs in the absence of the US field. Room temperature studies with the batch sonoreactor reveal a slow reduction process, producing temporally broad signals having an efficiency of approximately 68% of that arising from use of a conventional SnCl(2) reduction system. Molecular species of mercury are generated at high concentrations of formic and acetic acid. Factors affecting the generation of Hg(0) were optimized and the batch sonoreactor used for the determination of total mercury in SLRS-4 river water reference material.

  3. Application of Ultrasound-assisted Emulsification Microextraction ...

    African Journals Online (AJOL)

    NICOLAAS

    cNuclear Fuel Cycle Research School, Nuclear Science & Technology Research Institute, Atomic ... method, fine droplets of toluene were formed and dispersed in the sample with the help of ..... Validation for spiked water samples was carried out by using a .... emission spectrometry as a fast technique for the simultaneous.

  4. Ultrasound assisted biogas production from landfill leachate

    International Nuclear Information System (INIS)

    Oz, Nilgün Ayman; Yarimtepe, Canan Can

    2014-01-01

    Highlights: • Effect of low frequency ultrasound pretreatment on leachate was investigated. • Three different ultrasound energy inputs (200, 400 and 600 W/l) was applied. • Low-frequency ultrasound treatment increased soluble COD in landfill leachate. • Application of ultrasound to leachate increased biogas production about 40%. • Application of ultrasound to leachate increased total methane production rate about 20%. - Abstract: The aim of this study is to increase biogas production and methane yield from landfill leachate in anaerobic batch reactors by using low frequency ultrasound as a pretreatment step. In the first part of the study, optimum conditions for solubilization of organic matter in leachate samples were investigated using various sonication durations at an ultrasound frequency of 20 kHz. The level of organic matter solubilization during ultrasonic pretreatment experiments was determined by calculating the ratio of soluble chemical oxygen demand (sCOD) to total chemical oxygen demand (tCOD). The sCOD/tCOD ratio was increased from 47% in raw leachate to 63% after 45 min sonication at 600 W/l. Non-parametric Friedman’s test indicated that ultrasonic pretreatment has a significant effect on sCOD parameter for leachate (p < 0.05). In the second part of the study, anaerobic batch reactors were operated for both ultrasonically pretreated and untreated landfill leachate samples in order to assess the effect of sonication on biogas and methane production rate. In anaerobic batch reactor feed with ultrasonically pretreated leachate, 40% more biogas was obtained compared to the control reactor. For statistical analysis, Mann–Whitney U test was performed to compare biogas and methane production rates for raw and pretreated leachate samples and it has been found that ultrasonic pretreatment significantly enhanced biogas and methane production rates from leachate (p < 0.05) in anaerobic batch reactors. The overall results showed that low frequency ultrasound pretreatment can be potentially used for wastewater management especially with integration of anaerobic processes

  5. Ultrasound-assisted dealumination of zeolite Y

    Indian Academy of Sciences (India)

    zeolite Y the Si/Al molar ratio plays an important role in solid acidity .... determined using electron microprobe X-ray analysis. (EMPA) We also ... Surface area (m2/g) Pore Volume (cm3/g) XRD calculation .... for financial support for this work.

  6. Ultrasound assisted biogas production from landfill leachate

    Energy Technology Data Exchange (ETDEWEB)

    Oz, Nilgün Ayman, E-mail: nilgunayman@comu.edu.tr; Yarimtepe, Canan Can

    2014-07-15

    Highlights: • Effect of low frequency ultrasound pretreatment on leachate was investigated. • Three different ultrasound energy inputs (200, 400 and 600 W/l) was applied. • Low-frequency ultrasound treatment increased soluble COD in landfill leachate. • Application of ultrasound to leachate increased biogas production about 40%. • Application of ultrasound to leachate increased total methane production rate about 20%. - Abstract: The aim of this study is to increase biogas production and methane yield from landfill leachate in anaerobic batch reactors by using low frequency ultrasound as a pretreatment step. In the first part of the study, optimum conditions for solubilization of organic matter in leachate samples were investigated using various sonication durations at an ultrasound frequency of 20 kHz. The level of organic matter solubilization during ultrasonic pretreatment experiments was determined by calculating the ratio of soluble chemical oxygen demand (sCOD) to total chemical oxygen demand (tCOD). The sCOD/tCOD ratio was increased from 47% in raw leachate to 63% after 45 min sonication at 600 W/l. Non-parametric Friedman’s test indicated that ultrasonic pretreatment has a significant effect on sCOD parameter for leachate (p < 0.05). In the second part of the study, anaerobic batch reactors were operated for both ultrasonically pretreated and untreated landfill leachate samples in order to assess the effect of sonication on biogas and methane production rate. In anaerobic batch reactor feed with ultrasonically pretreated leachate, 40% more biogas was obtained compared to the control reactor. For statistical analysis, Mann–Whitney U test was performed to compare biogas and methane production rates for raw and pretreated leachate samples and it has been found that ultrasonic pretreatment significantly enhanced biogas and methane production rates from leachate (p < 0.05) in anaerobic batch reactors. The overall results showed that low frequency ultrasound pretreatment can be potentially used for wastewater management especially with integration of anaerobic processes.

  7. Microbial Inactivation by Ultrasound Assisted Supercritical Fluids

    Science.gov (United States)

    Benedito, Jose; Ortuño, Carmen; Castillo-Zamudio, Rosa Isela; Mulet, Antonio

    A method combining supercritical carbon dioxide (SC-CO2) and high power ultrasound (HPU) has been developed and tested for microbial/enzyme inactivation purposes, at different process conditions for both liquid and solid matrices. In culture media, using only SC-CO2, the inactivation rate of E. coli and S. cerevisiae increased with pressure and temperature; and the total inactivation (7-8 log-cycles) was attained after 25 and 140 min of SC-CO2 (350 bar, 36 °C) treatment, respectively. Using SC-CO2+HPU, the time for the total inactivation of both microorganisms was reduced to only 1-2 min, at any condition selected. The SC-CO2+HPU inactivation of both microorganisms was slower in juices (avg. 4.9 min) than in culture media (avg. 1.5 min). In solid samples (chicken, turkey ham and dry-cured pork cured ham) treated with SC-CO2 and SC-CO2+HPU, the inactivation rate of E. coli increased with temperature. The application of HPU to the SC-CO2 treatments accelerated the inactivation rate of E. coli and that effect was more pronounced in treatments with isotonic solution surrounding the solid food samples. The application of HPU enhanced the SC-CO2 inactivation mechanisms of microorganisms, generating a vigorous agitation that facilitated the CO2 solubilization and the mass transfer process. The cavitation generated by HPU could damage the cell walls accelerating the extraction of vital constituents and the microbial death. Thus, using the combined technique, reasonable industrial processing times and mild process conditions could be used which could result into a cost reduction and lead to the minimization in the food nutritional and organoleptic changes.

  8. Ultrasound-assisted swelling of bacterial cellulose

    OpenAIRE

    Song, J.; Su, Jing; Loureiro, Ana; Sá, M.; Cavaco-Paulo, Artur; Kim, Hye Rim; Silva, Carla

    2017-01-01

    Bacterial cellulose (BC) was obtained by static cultivation using commercial BC gel from scoby. BC membranes (oven dried and freeze-dried) were swelled with 8% NaOH, in absence and in presence of ultrasound (US), for 30, 60 and 90 min. The influence of swelling conditions on both physico-chemical properties and molecules entrapment was evaluated. Considering the highest levels of entrapment, an optimum swelling procedure was established: 8% NaOH for 30 min. at room temperature in the presence...

  9. Graphene-ionic liquid composites

    Energy Technology Data Exchange (ETDEWEB)

    Aksay, Ilhan A.; Korkut, Sibel; Pope, Michael; Punckt, Christian

    2016-11-01

    Method of making a graphene-ionic liquid composite. The composite can be used to make elec-trodes for energy storage devices, such as batteries and supercapacitors. Dis-closed and claimed herein is method of making a graphene-ionic liquid com-posite, comprising combining a graphene source with at least one ionic liquid and heating the combination at a temperature of at least about 130 .degree. C.

  10. Sonochemical assisted hydrothermal synthesis of ZnO: Cr nanoparticles loaded activated carbon for simultaneous ultrasound-assisted adsorption of ternary toxic organic dye: Derivative spectrophotometric, optimization, kinetic and isotherm study.

    Science.gov (United States)

    Jamshidi, M; Ghaedi, M; Dashtian, K; Hajati, S; Bazrafshan, A A

    2016-09-01

    Chromium doped zinc oxide nanoparticles (ZnO: Cr-NPs) was synthesized by ultrasonically assisted hydrothermal method and characterized by FE-SEM, XRD and TEM analysis. Subsequently, this composite ultrasonically assisted was deposited on activated carbon (ZnO: Cr-NPs-AC) and used for simultaneous ultrasound-assisted removal of three toxic organic dye namely of malachite green (MG), eosin yellow (EY) and Auramine O (AO). Dyes spectra overlap in mixture (major problem for simultaneous investigation) of this systems was extensively resolved by derivative spectrophotometric method. The magnitude of variables like initial dyes concentration, adsorbent mass and sonication time influence on dyes removal was optimized using small central composite design (CCD) combined with desirability function (DF) approach, while pH was studied by one-a-time approach. The maximized removal percentages at desirability of 0.9740 was set as follow: pH 6.0, 0.019g ZnO: Cr-NPs-AC, 3.9min sonication at 4.5, 4.8 and 4.7mgL(-1) of MG, EY and AO, respectively. Above optimized points lead to achievement of removal percentage of 98.36%, 97.24%, and 99.26% correspond to MG, EY and AO, respectively. ANOVA for each dyes based p-value less than (<0.0001) suggest highly efficiency of CCD model for prediction of data concern to simultaneous removal of these dyes within 95% confidence interval, while their F-value for MG, EY and AO is 935, 800.2, and 551.3, respectively, that confirm low participation of this them in signal. The value of multiple correlation coefficient R(2), adjusted and predicted R(2) for simultaneous removal of MG is 0.9982, 0.9972 and 0.9940, EY is 0.9979, 0.9967 and 0.9930 and for AO is 0.9970, 0.9952 and 0.9939. The adsorption rate well fitted by pseudo second-order and Langmuir model via high, economic and profitable adsorption capacity of 214.0, 189.7 and 211.6mgg(-1) for MG, EY and AO, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. In situ derivatization-ultrasound-assisted dispersive liquid-liquid microextraction for the determination of neurotransmitters in Parkinson's rat brain microdialysates by ultra high performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    He, Yongrui; Zhao, Xian-En; Zhu, Shuyun; Wei, Na; Sun, Jing; Zhou, Yubi; Liu, Shu; Liu, Zhiqiang; Chen, Guang; Suo, Yourui; You, Jinmao

    2016-08-05

    Simultaneous monitoring of several neurotransmitters (NTs) linked to Parkinson's disease (PD) has important scientific significance for PD related pathology, pharmacology and drug screening. A new simple, fast and sensitive analytical method, based on in situ derivatization-ultrasound-assisted dispersive liquid-liquid microextraction (in situ DUADLLME) in a single step, has been proposed for the quantitative determination of catecholamines and their biosynthesis precursors and metabolites in rat brain microdialysates. The method involved the rapid injection of the mixture of low toxic bromobenzene (extractant) and acetonitrile (dispersant), which containing commercial Lissamine rhodamine B sulfonyl chloride (LRSC) as derivatization reagent, into the aqueous phase of sample and buffer, and the following in situ DUADLLME procedure. After centrifugation, 50μL of the sedimented phase (bromobenzene) was directly injected for ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) detection in multiple reaction monitoring (MRM) mode. This interesting combination brought the advantages of speediness, simpleness, low matrix effects and high sensitivity in an effective way. Parameters of in situ DUADLLME and UHPLC-MS/MS conditions were all optimized in detail. The optimum conditions of in situ DUADLLME were found to be 30μL of microdialysates, 150μL of acetonitrile containing LRSC, 50μL of bromobenzene and 800μL of NaHCO3-Na2CO3 buffer (pH 10.5) for 3.0min at 37°C. Under the optimized conditions, good linearity was observed with LODs (S/N>3) and LOQs (S/N>10) of LRSC derivatized-NTs in the range of 0.002-0.004 and 0.007-0.015 nmol/L, respectively. It also brought good precision (3.2-12.8%, peak area CVs%), accuracy (94.2-108.6%), recovery (94.5-105.5%) and stability (3.8-8.1%, peak area CVs%) results. Moreover, LRSC derivatization significantly improved chromatographic resolution and MS detection sensitivity of NTs when compared with the

  12. Novel routes to liquid-based self-healing polymer systems

    NARCIS (Netherlands)

    Mookhoek, S.D.

    2010-01-01

    Inspired by the current state-of-the-art and the progressing advancements in the field of self-healing materials, this thesis addresses several novel routes to advance the concept of liquid-based self-healing polymer systems. This thesis presents the concept and characterisation of a one-component

  13. Controlled electrodeposition of Au monolayer film on ionic liquid

    Science.gov (United States)

    Ma, Qiang; Pang, Liuqing; Li, Man; Zhang, Yunxia; Ren, Xianpei; Liu, Shengzhong Frank

    2016-05-01

    Gold (Au) nanoparticles have been attractive for centuries for their vibrant appearance enhanced by their interaction with sunlight. Nowadays, there have been tremendous research efforts to develop them for high-tech applications including therapeutic agents, sensors, organic photovoltaics, medical applications, electronics and catalysis. However, there remains to be a challenge to fabricate a monolayer Au coating with complete coverage in controlled fashion. Here we present a facile method to deposit a uniform Au monolayer (ML) film on the [BMIM][PF6] ionic liquid substrate using an electrochemical deposition process. It demonstrates that it is feasible to prepare a solid phase coating on the liquid-based substrate. Moreover, the thickness of the monolayer coating can be controlled to a layer-by-layer accuracy.

  14. Ionic and Molecular Liquids

    DEFF Research Database (Denmark)

    Chaban, Vitaly V.; Prezhdo, Oleg

    2013-01-01

    Because of their outstanding versatility, room-temperature ionic liquids (RTILs) are utilized in an ever increasing number of novel and fascinating applications, making them the Holy Grail of modern materials science. In this Perspective, we address the fundamental research and prospective...... applications of RTILs in combination with molecular liquids, concentrating on three significant areas: (1) the use of molecular liquids to decrease the viscosity of RTILs; (2) the role of RTIL micelle formation in water and organic solvents; and (3) the ability of RTILs to adsorb pollutant gases. Current...

  15. Ionic liquids, electrolyte solutions including the ionic liquids, and energy storage devices including the ionic liquids

    Science.gov (United States)

    Gering, Kevin L.; Harrup, Mason K.; Rollins, Harry W.

    2015-12-08

    An ionic liquid including a phosphazene compound that has a plurality of phosphorus-nitrogen units and at least one pendant group bonded to each phosphorus atom of the plurality of phosphorus-nitrogen units. One pendant group of the at least one pendant group comprises a positively charged pendant group. Additional embodiments of ionic liquids are disclosed, as are electrolyte solutions and energy storage devices including the embodiments of the ionic liquid.

  16. Ionic liquids comprising heteraromatic anions

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, William F.; Brennecke, Joan F.; Maginn, Edward J.; Mindrup, Elaine; Gurkan, Burcu; Price, Erica; Goodrich, Brett

    2018-04-24

    Some embodiments described herein relate to ionic liquids comprising an anion of a heteraromatic compound such as optionally substituted pyrrolide, optionally substituted pyrazolide, optionally substituted indolide, optionally substituted phospholide, or optionally substituted imidazolide. Methods and devices for gas separation or gas absorption related to these ionic liquids are also described herein.

  17. Supercritical fluids in ionic liquids

    NARCIS (Netherlands)

    Kroon, M.C.; Peters, C.J.; Plechkova, N.V.; Seddon, K.R.

    2014-01-01

    Ionic liquids and supercritical fluids are both alternative environmentally benign solvents, but their properties are very different. Ionic liquids are non-volatile but often considered highly polar compounds, whereas supercritical fluids are non-polar but highly volatile compounds. The combination

  18. CADDIS Volume 2. Sources, Stressors and Responses: Ionic Strength

    Science.gov (United States)

    Introduction to the ionic strength module, when to list ionic strength as a candidate cause, ways to measure ionic strength, simple and detailed conceptual diagrams for ionic strength, ionic strength module references and literature reviews.

  19. Controlled electrodeposition of Au monolayer film on ionic liquid

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Qiang; Pang, Liuqing; Li, Man; Zhang, Yunxia; Ren, Xianpei [Key Laboratory of Applied Surface and Colloid Chemistry, National Ministry of Education, Shaanxi Engineering Lab for Advanced Energy Technology, School of Materials Science and Engineering, Shaanxi Normal University, Xi’an 710062 (China); Liu, Shengzhong Frank, E-mail: szliu@dicp.ac.cn [Key Laboratory of Applied Surface and Colloid Chemistry, National Ministry of Education, Shaanxi Engineering Lab for Advanced Energy Technology, School of Materials Science and Engineering, Shaanxi Normal University, Xi’an 710062 (China); Dalian Institute of Chemical Physics, Dalian National Laboratory for Clean Energy, Chinese Academy of Sciences, Dalian 116023 (China)

    2016-05-15

    Highlights: • We fabricate Au monolayer film on Ionic liquid substrate using an electrochemical deposition technique. • Au monolayer film was deposited on a “soft substrate” for the first time. • Au monolayer film can contribute extra Raman enhancement. - Abstract: Gold (Au) nanoparticles have been attractive for centuries for their vibrant appearance enhanced by their interaction with sunlight. Nowadays, there have been tremendous research efforts to develop them for high-tech applications including therapeutic agents, sensors, organic photovoltaics, medical applications, electronics and catalysis. However, there remains to be a challenge to fabricate a monolayer Au coating with complete coverage in controlled fashion. Here we present a facile method to deposit a uniform Au monolayer (ML) film on the [BMIM][PF{sub 6}] ionic liquid substrate using an electrochemical deposition process. It demonstrates that it is feasible to prepare a solid phase coating on the liquid-based substrate. Moreover, the thickness of the monolayer coating can be controlled to a layer-by-layer accuracy.

  20. Dopamine-Mediated Sclerotization of Regenerated Chitin in Ionic Liquid.

    Science.gov (United States)

    Oh, Dongyeop X; Shin, Sara; Lim, Chanoong; Hwang, Dong Soo

    2013-09-06

    Chitin is a promising structural material for biomedical applications, due to its many advantageous properties and abundance in nature. However, its usage and development in the biomedical field have been stagnant, because of chitin's poor mechanical properties in wet conditions and the difficulties in transforming it into an applicable form. To overcome these challenges, we created a novel biomimetic chitin composite. This regenerated chitin, prepared with ionic liquid, showed improved mechanical properties in wet conditions by mimicking insect cuticle and squid beak sclerotization, i.e. , catechol-meditated cross-linking. By ionic liquid-based heat treatment, dopamine oxidation produced melanin-like compounds and dopamine-meditated cross-links without any solvent evaporation and oxidant utilization. The dopamine-meditated sclerotization increased the ultimate tensile strength (UTS) of the regenerated chitin by 2.52-fold, measured after six weeks of phosphate-buffered saline (PBS) submersion. In addition, the linear swelling ratio (LSR) of the chitin film was reduced by about 22%. This strategy raises a possibility of using regenerated chitin as an artificial hard tissue in wet conditions.

  1. Dopamine-Mediated Sclerotization of Regenerated Chitin in Ionic Liquid

    Directory of Open Access Journals (Sweden)

    Dongyeop X. Oh

    2013-09-01

    Full Text Available Chitin is a promising structural material for biomedical applications, due to its many advantageous properties and abundance in nature. However, its usage and development in the biomedical field have been stagnant, because of chitin’s poor mechanical properties in wet conditions and the difficulties in transforming it into an applicable form. To overcome these challenges, we created a novel biomimetic chitin composite. This regenerated chitin, prepared with ionic liquid, showed improved mechanical properties in wet conditions by mimicking insect cuticle and squid beak sclerotization, i.e., catechol-meditated cross-linking. By ionic liquid-based heat treatment, dopamine oxidation produced melanin-like compounds and dopamine-meditated cross-links without any solvent evaporation and oxidant utilization. The dopamine-meditated sclerotization increased the ultimate tensile strength (UTS of the regenerated chitin by 2.52-fold, measured after six weeks of phosphate-buffered saline (PBS submersion. In addition, the linear swelling ratio (LSR of the chitin film was reduced by about 22%. This strategy raises a possibility of using regenerated chitin as an artificial hard tissue in wet conditions.

  2. Hydrogen bonding in ionic liquids.

    Science.gov (United States)

    Hunt, Patricia A; Ashworth, Claire R; Matthews, Richard P

    2015-03-07

    Ionic liquids (IL) and hydrogen bonding (H-bonding) are two diverse fields for which there is a developing recognition of significant overlap. Doubly ionic H-bonds occur when a H-bond forms between a cation and anion, and are a key feature of ILs. Doubly ionic H-bonds represent a wide area of H-bonding which has yet to be fully recognised, characterised or explored. H-bonds in ILs (both protic and aprotic) are bifurcated and chelating, and unlike many molecular liquids a significant variety of distinct H-bonds are formed between different types and numbers of donor and acceptor sites within a given IL. Traditional more neutral H-bonds can also be formed in functionalised ILs, adding a further level of complexity. Ab initio computed parameters; association energies, partial charges, density descriptors as encompassed by the QTAIM methodology (ρBCP), qualitative molecular orbital theory and NBO analysis provide established and robust mechanisms for understanding and interpreting traditional neutral and ionic H-bonds. In this review the applicability and extension of these parameters to describe and quantify the doubly ionic H-bond has been explored. Estimating the H-bonding energy is difficult because at a fundamental level the H-bond and ionic interaction are coupled. The NBO and QTAIM methodologies, unlike the total energy, are local descriptors and therefore can be used to directly compare neutral, ionic and doubly ionic H-bonds. The charged nature of the ions influences the ionic characteristics of the H-bond and vice versa, in addition the close association of the ions leads to enhanced orbital overlap and covalent contributions. The charge on the ions raises the energy of the Ylp and lowers the energy of the X-H σ* NBOs resulting in greater charge transfer, strengthening the H-bond. Using this range of parameters and comparing doubly ionic H-bonds to more traditional neutral and ionic H-bonds it is clear that doubly ionic H-bonds cover the full range of weak

  3. Lattice dynamics of ionic crystals