Surfactant-enhanced liquid-liquid microextraction coupled to micro-solid phase extraction onto highly hydrophobic magnetic nanoparticles

International Nuclear Information System (INIS)

Giannoulis, Kiriakos M.; Giokas, Dimosthenis L.; Tsogas, George Z.; Vlessidis, Athanasios G.; Zhu, Qing; Pan, Qinmin

2013-01-01

We are presenting a simplified alternative method for dispersive liquid-liquid microextraction (DLLME) by resorting to the use of surfactants as emulsifiers and micro solid-phase extraction (μ-SPE). In this combined procedure, DLLME of hydrophobic components is initially accomplished in a mixed micellar/microemulsion extractant phase that is prepared by rapidly mixing a non-ionic surfactant and 1-octanol in aqueous medium. Then, and in contrast to classic DLLME, the extractant phase is collected by highly hydrophobic polysiloxane-coated core-shell Fe 2 O 3 (at)C magnetic nanoparticles. Hence, the sample components are the target analyte in the DLLME which, in turn, becomes the target analyte of the μ-SPE step. This 2-step approach represents a new and simple DLLME procedure that lacks tedious steps such as centrifugation, thawing, or delicate collection of the extractant phase. As a result, the analytical process is accelerated and the volume of the collected phase does not depend on the volume of the extraction solvent. The method was applied to extract cadmium in the form of its pyrrolidine dithiocarbamate chelate from spiked water samples prior to its determination by FAAS. Detection limits were brought down to the low μg L −1 levels by preconcentrating 10 mL samples with satisfactory recoveries (96.0–108.0 %). (author)

[Determination of fatty acid esters of chloropropanediols in diet samples by gas chromatography-mass spectrometry coupled with solid-supported liquid-liquid extraction].

Science.gov (United States)

Gao, Jie; Liu, Qing; Han, Feng; Miao, Hong; Zhao, Yunfeng; Wu, Yongning

2014-05-01

To establish a method for the determination of fatty acid esters of 3-monochloropropane-1, 2-diol (3-MCPD) and 2-monochloropropane-1, 3-diol (2-MCPD) in diet samples by gas chromatography-mass spectrometry (GC-MS) with solid-supported liquid-liquid extraction (SLE). Diet samples were ultrasonically extracted by hexane, followed by ester cleavage reaction with sodium methylate in methanol, and then purified by solid-supported liquid-liquid extraction. (SLE) using diatomaceous earth as the sorbent. After derivatization with heptafluorobutyrylimidazole, the analytes were detected by GC-MS and quantified by the deuterated internal standards. The limits of detection (LODs) of 3-MCPD esters and 2-MCPD esters in different diet samples were 0.002 - 0.005 mg/kg and 0.002 - 0.006 mg/kg. The average recoveries of 3-MCPD esters and 2-MCPD esters at the spiking levels of 0.05 and 0.1 mg/kg in the diet samples were in the range of 65.9% - 104.2% and 75.4% - 118.0%, respectively, with the relative standard deviations in the range of 2.2% - 14.2% and 0.8% - .13.9%. The method is simple, accurate and rugged for the determination of fatty acid esters of 3-MCPD and 2-MCPD in diet samples.

Solid-phase extraction assisted dispersive liquid-liquid microextraction based on solidification of floating organic droplet to determine sildenafil and its analogues in dietary supplements.

Science.gov (United States)

Li, Jing; Roh, Si Hun; Shaodong, Jia; Hong, Ji Yeon; Lee, Dong-Kyu; Shin, Byong-Kyu; Park, Jeong Hill; Lee, Jeongmi; Kwon, Sung Won

2017-08-01

A novel analytical method for the simultaneous determination of the concentration of sildenafil and its five analogues in dietary supplements using solid-phase extraction assisted reversed-phase dispersive liquid-liquid microextraction based on solidification of floating organic droplet combined with ion-pairing liquid chromatography with an ultraviolet detector was developed. Parameters that affect extraction efficiency were systematically investigated, including the type of solid-phase extraction cartridge, pH of the extraction environment, and the type and volume of extraction and dispersive solvent. The method linearity was in the range of 5.0-100 ng/mL for sildenafil, homosildenafil, udenafil, benzylsildenafil, and thiosildenafil and 10-100 ng/mL for acetildenafil. The coefficients of determination were ≥0.996 for all regression curves. The sensitivity values expressed as limit of detection were between 2.5 and 7.5 ng/mL. Furthermore, intraday and interday precisions expressed as relative standard deviations were less than 5.7 and 9.9%, respectively. The proposed method was successfully applied to the analysis of sildenafil and its five analogues in complex dietary supplements. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Liquid-liquid and solid-phase extractions of phenols from virgin olive oil and their separation by chromatographic and electrophoretic methods.

Science.gov (United States)

Bendini, Alessandra; Bonoli, Matteo; Cerretani, Lorenzo; Biguzzi, Barbara; Lercker, Giovanni; Toschi, Tullia Gallina

2003-01-24

The high oxidative stability of virgin olive oil is related to its high monounsaturated/polyunsaturated ratio and to the presence of antioxidant compounds, such as tocopherols and phenols. In this paper, the isolation of phenolic compounds from virgin olive oil, by different methods, was tested and discussed. Particularly liquid-liquid and solid-phase extraction methods were compared, assaying, for the latter, three stationary phases (C8, C18 and Diol) and several elution mixtures. Quantification of phenolic and o-diphenolic substances in the extracts was performed by the traditional Folin-Ciocalteau method and the sodium molybdate reaction, respectively. Furthermore, the quantification of phenolic compounds in the extracts and in a standard mixture was carried out both with diode array and mass spectrometric detection and capillary zone electrophoresis.

Extraction products of solid carbonaceous materials

Energy Technology Data Exchange (ETDEWEB)

1937-11-04

A method is described for the manufacture of liquid products from pressure extracts of solid carbon-containing material by destructive hydrogenation, characterized in that the pressure extracts are hydrogenated in admixture with products of high-molecular weight formed during a previous destructive hydrogenation of another part of the same or other pressure extract and which has been collected as liquid without extensive cooling of the hot products of the reaction, which came from the reaction chamber where the previous destructive hydrogenation took place.

Cone-shaped membrane liquid phase micro extraction

International Nuclear Information System (INIS)

Hong, Heng See; Sanagi, M.M.; Ibrahim, W.A.W.; Naim, A.A.

2008-01-01

A novel sample pre-treatment technique termed cone-shaped membrane liquid phase micro extraction (CSM-LPME) was developed and combined with micro-liquid chromatography (micro-LC) for the determination of selected pesticides in water samples. Several important extraction parameters such as types of extraction solvent, agitation rate, pH value, total exposure time and effect of salt and humic acids were investigated and optimized. Enrichment factors of >50 folds were easily achieved within 20 min of extraction. The new developed method demonstrated an excellent performance in terms of speed, cost effectiveness, reproducibility, as well as exceptional low detection limits. Current work provides a great interest to further investigate on the applicability of the CSM-LPME technique in analytical chemistry and explores the possibility of replacing conventional extraction techniques such as soxhlet, solid phase extraction (SPE) and solid phase micro extraction (SPME). (author)

Application of dispersive liquid-liquid microextraction and dispersive micro-solid-phase extraction for the determination of quinolones in swine muscle by high-performance liquid chromatography with diode-array detection

International Nuclear Information System (INIS)

Tsai, Wen-Hsien; Chuang, Hung-Yi; Chen, Ho-Hsien; Huang, Joh-Jong; Chen, Hwi-Chang; Cheng, Shou-Hsun; Huang, Tzou-Chi

2009-01-01

Dispersive liquid-liquid microextraction (DLLME) and dispersive micro-solid-phase extraction (DMSPE) are two simple and low-cost sample preparation methods for liquid samples. In this work, these two methods were applied to solid tissue sample for the determination of seven quinolones by high-performance liquid chromatography with diode-array detection (HPLC-DAD). After the homogenization of the swine muscle with acetonitrile and salt-promoted partitioning, small amounts of the extract were used for the DLLME and DMSPE methods. In the DLLME approach, the target analytes in the extraction solvent were rapidly extracted into a small volume of dichloromethane for drying and the residue was reconstituted for HPLC-DAD analysis. In the DMSPE approach, the target analytes in the extraction solvent were trapped by dispersive silica-based PSA (primary and secondary amine) sorbents and desorbed into a small amount of desorption solution for HPLC-DAD analysis. Under the optimal conditions, relative recoveries were determined for swine muscle spiked 50-200 μg kg -1 and quantification was achieved by matrix-matched calibration. The calibration curves of seven quinolones showed linearity with a correlation coefficient value above 0.998 for both approaches. Relative recoveries ranged from 93.0 to 104.7% and from 95.5 to 111.0% for DLLME and DMSPE, respectively. Limits of detection (LODs) ranged from 5.6 to 23.8 μg kg -1 and from 7.5 to 26.3 μg kg -1 for DLLME and DMSPE, respectively.

Solid-Liquid Separation Properties of Thermoregulated Dicationic Ionic Liquid as Extractant of Dyes from Aqueous Solution

Directory of Open Access Journals (Sweden)

Rui Lv

2018-01-01

Full Text Available Two thermoregulated dicationic ionic liquids were synthesized and applied for effective extraction of the common dye malachite green oxalate (MG. The extraction parameters such as amount of ionic liquids, pH of water phase, extraction time, cooling time, and centrifugal time on the extraction efficiency were investigated systematically. It revealed that the dye has been successfully extracted into the ionic liquids, with high extraction efficiency higher than 98%, and recovery of 98.2%–100.8%, respectively. Furthermore, these ionic liquids can be recycled easily after elution. The reusable yields were 87.1% and 88.7%. The extraction of the dye into the thermoregulated ionic liquid provides a method of minimizing pollution of waste water potentially.

A technical review of liquid/liquid and solid/liquid separation equipment in the field of nuclear-fuel reprocessing

International Nuclear Information System (INIS)

Vassallo, G.

1981-01-01

Liquid/liquid extraction is generally accepted as the preferred method in nuclear-fuel reprocessing. However, although many types of liquid/liquid contactors are available, only a few meet the stringent specifications set by the nuclear industry. This report discusses the criteria for contactor selection and then reviews the most important types, namely packed columns, pulsed columns, mixer-setters and centrifugal contactors. Finally, a short section concerned with solid/liquid separations is included because of the possible deleterious effects caused by solids in liquid/liquid contactors

The solid-liquid extraction separation of lithium isotopes by porous composite materials doped with ionic liquids and 2,2'-binaphthyldiyl-17-crown-5

International Nuclear Information System (INIS)

Xiao-Li Sun; Ling Gu; Dan Qiu; Dong-Hong Ren; Zaijun Li; Zhi-Guo Gu; Jiangnan University, Wuxi

2015-01-01

A green and efficient solid-liquid extraction method of lithium isotopes separation by porous composite materials doped with imidazolium ionic liquids and 2,2'-binaphthyldiyl-17-crown-5 has been reported in this paper. The composite materials of mesoporous silica and impregnated resin were synthesized by sol-gel and direct impregnation process, respectively. Various extraction parameters such as the concentration of lithium salt, anion of lithium salt, initial pH, time and temperature were investigated. Under optimized conditions, the maximum single-stage separation factor of 6 Li/ 7 Li was 1.048 ± 0.002, the maximum extraction efficiency was 15.86 %. The sorbents can be regenerated easily with HCl solution and reused repeatedly. (author)

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.

Determination of multi-class herbicides in soil by liquid-solid extraction coupled with headspace solid phase microextraction method

Directory of Open Access Journals (Sweden)

Đurović-Pejčev Rada

2016-01-01

Full Text Available A method is described for simultaneous determination of five herbicides (metribuzin, acetochlor, clomazone, oxyfluorfen and dimethenamid belonging to different pesticides groups in soil samples. Developed headspace solid phase microextraction method (HS-SPME in combination with liquid-solid sample preparation (LS was optimized and applied in the analysis of some agricultural samples. Optimization of microextraction conditions, such as temperature, extraction time and sodium chloride (NaCl content was perfor-med using 100 μm polydimethyl-siloxane (PDMS fiber. The extraction effi-ciencies of methanol, methanol:acetone=1:1 and methanol:acetone:hexane= =2:2:1 and the optimum number of extraction steps during the sample prepa-ration, were tested, as well. Gas chromatography-mass spectrometry (GC-MS was used for detection and quantification, obtaining relative standard deviation (RSD below 13%, and recovery values higher than 83% for multiple analyses of soil samples fortified at 30 μg kg-1 of each herbicide. Limits of detection (LOD were less than 1.2 μg kg-1 for all the studied herbicides. [Projekat Ministarstva nauke Republike Srbije, br. TR31043 i br. III43005

Solid-phase extraction in combination with dispersive liquid-liquid microextraction and ultra-high performance liquid chromatography-tandem mass spectrometry analysis: the ultra-trace determination of 10 antibiotics in water samples.

Science.gov (United States)

Liang, Ning; Huang, Peiting; Hou, Xiaohong; Li, Zhen; Tao, Lei; Zhao, Longshan

2016-02-01

A novel method, solid-phase extraction combined with dispersive liquid-liquid microextraction (SPE-DLLME), was developed for ultra-preconcentration of 10 antibiotics in different environmental water samples prior to ultra-high performance liquid chromatography-tandem mass spectrometry detection. The optimized results were obtained as follows: after being adjusted to pH 4.0, the water sample was firstly passed through PEP-2 column at 10 mL min(-1), and then methanol was used to elute the target analytes for the following steps. Dichloromethane was selected as extraction solvent, and methanol/acetonitrile (1:1, v/v) as dispersive solvent. Under optimal conditions, the calibration curves were linear in the range of 1-1000 ng mL(-1) (sulfamethoxazole, cefuroxime axetil), 5-1000 ng mL(-1) (tinidazole), 10-1000 ng mL(-1) (chloramphenicol), 2-1000 ng mL(-1) (levofloxacin oxytetracycline, doxycycline, tetracycline, and ciprofloxacin) and 1-400 ng mL(-1) (sulfadiazine) with a good precision. The LOD and LOQ of the method were at very low levels, below 1.67 and 5.57 ng mL(-1), respectively. The relative recoveries of the target analytes were in the range from 64.16% to 99.80% with relative standard deviations between 0.7 and 8.4%. The matrix effect of this method showed a great decrease compared with solid-phase extraction and a significant value of enrichment factor (EF) compared with dispersive liquid-liquid microextraction. The developed method was successfully applied to the extraction and analysis of antibiotics in different water samples with satisfactory results.

Simultaneous solid phase extraction of cobalt, strontium and cesium from liquid radioactive waste using microcrystalline naphthalene

International Nuclear Information System (INIS)

Hamed, Mostafa Mohamed; Attallah, Mohamed Fathy; Metwally, Sayed Sayed

2014-01-01

Most of the procedures developed for the extraction of cobalt, strontium and cesium by solid phase extraction do not employ simultaneous extraction of them. In this study, rapid simultaneous removal of Co 2+ , Sr 2+ and Cs + on microcrystalline naphthalene as solid-phase extractant was investigated. These ions were allowed to form chelates with oxine and then adsorbed on freshly microcrystalline naphthalene from aqueous solutions. The solid phase extraction procedure (SPE) was optimized by using model solution containing Co 2+ , Sr 2+ and Cs + in batch system. The effects of different parameters such as variation in pH, reagent concentration, standing time, naphthalene solution concentration and contact time on the simultaneous removal of these ions was studied. The obtained results indicated that, sorption was found to be rapid, and the percentage removal of Co 2+ , Sr 2+ and Cs + was found to be 98, 79 and 68% within 10 min, respectively. The kinetics of the sorption process was investigated to understand the kinetic characteristics of sorption of metal chelates onto microcrystalline naphthalene. The developed procedure has been successfully applied to the removal and recovery of 60 Co and 134 Cs from liquid radioactive waste. The parameters can be used for designing a plant for treatment of wastewater economically.

[Influence of liquid or solid culture conditions on the volatile components of mycelia of Isariacateinannulata].

Science.gov (United States)

Zhang, Delong; Wang, Xiaodong; Lu, Ruili; Li, Kangle; Hu, Fenglin

2011-12-01

To determine the volatile components of mycelia of Isaria cateinannulata cultured under different culture conditions, and to analyze the relationships between the culture conditions and volatile metabolites. Mycelia were cultured in solid plates with SDAY medium and liquid shake flasks with SDY medium. The culture conditions were at 25 degrees C and 8 days. Volatile components in the mycelia of I. cateinannulata were extracted with simultaneous distillation extraction and analyzed by gas chromatography-mass spectrometry. Alkenes, alkanes, heterocyclic and polycyclic aromatic hydrocarbons (PAH) were existed abundantly both in the mycelia of liquid and solid cultures, but the kinds and relative concentrations of the volatile components in mycelia of liquid and solid cultures were very different. Forty-one compounds were identified from the mycelia of solid culture and 32 compounds were identified from the mycelia of liquid culture. Esters, quinones and oximes were only found in solid cultured mycelia whereas carboxylic acids were only discovered in the mycelia of liquid culture. At the same time, mycelia of liquid culture contained much more phenols. The most abundant compounds in mycelia of liquid and solid cultures were hydrocarbons. The volatile extracts of solid cultured mycelia contained 57.6% alkenes and 9.19% alkanes. The volatile extracts of liquid cultured mycelia contained 7.85% alkenes and 22.4% alkanes. Liquid or solid culture conditions influenced the volatile components of mycelia of I. cateinannulata.

Contacting solids and liquids

International Nuclear Information System (INIS)

Robinson, L.F.

1980-01-01

A solids/liquid (or slurry/liquid) contactor is described comprising a container through which the phases flow, rotatable discs with a rotor dividing the container into a series of interconnected compartments and, in at least some of the compartments, receptacles extending between the discs to effect phase transfer. At least one of the compartments is free of receptacles or has receptacles arranged on a smaller diameter than in other compartments to form a settling chamber. The contactor may be used in the extraction of oil-sands or uranium or purification of china clay. (author)

Determination of chiral pharmaceuticals and illicit drugs in wastewater and sludge using microwave assisted extraction, solid-phase extraction and chiral liquid chromatography coupled with tandem mass spectrometry.

Science.gov (United States)

Evans, Sian E; Davies, Paul; Lubben, Anneke; Kasprzyk-Hordern, Barbara

2015-07-02

This is the first study presenting a multi-residue method allowing for comprehensive analysis of several chiral pharmacologically active compounds (cPACs) including beta-blockers, antidepressants and amphetamines in wastewater and digested sludge at the enantiomeric level. Analysis of both the liquid and solid matrices within wastewater treatment is crucial to being able to carry out mass balance within these systems. The method developed comprises filtration, microwave assisted extraction and solid phase extraction followed by chiral liquid chromatography coupled with tandem mass spectrometry to analyse the enantiomers of 18 compounds within all three matrices. The method was successfully validated for 10 compounds within all three matrices (amphetamine, methamphetamine, MDMA, MDA, venlafaxine, desmethylvenlafaxine, citalopram, metoprolol, propranolol and sotalol), 7 compounds validated for the liquid matrices only (mirtazapine, salbutamol, fluoxetine, desmethylcitalopram, atenolol, ephedrine and pseudoephedrine) and 1 compound (alprenolol) passing the criteria for solid samples only. The method was then applied to wastewater samples; cPACs were found at concentration ranges in liquid matrices of: 1.7 ng L(-1) (metoprolol) - 1321 ng L(-1) (tramadol) in influent, solid matrix digested sludge: 0.4 ng g(-1) (metoprolol) - 275 ng g(-1) (citalopram). Enantiomeric profiling revealed that studied compounds were present in analysed samples in non-racemic composition. Furthermore, enantiomeric composition of studied analytes differed in liquid and solid matrices. This demonstrates that not analysing the solid fraction of wastewater may lead to over-estimation of the removal rates of cPACs as well as possible misrepresentation of the enantiomeric fraction of the compounds as they leave the wastewater treatment plant. Consequently risks from cPACs entering the environment might be higher than

Quantification of four ionophores in soil, sediment and manure using pressurised liquid extraction

DEFF Research Database (Denmark)

Bak, Søren Alex; Hansen, Martin; Pedersen, Kenneth Munk

2013-01-01

A multi-residue pressurised liquid extraction (PLE) methodology has been established for the determination of the four ionophores: lasalocid, monensin, salinomycin and narasin in solid environmental matrices. The PLE methodology is combined with solid phase extraction as clean-up using liquid...

Analysis and Comparison of the Antioxidant Component of Portulaca Oleracea Leaves Obtained by Different Solid-Liquid Extraction Techniques

Science.gov (United States)

Conte, Esterina

2017-01-01

Portulaca oleracea is a wild plant pest of orchards and gardens, but is also an edible vegetable rich in beneficial nutrients. It possesses many antioxidant properties due to the high content of vitamins, minerals, omega-3 essential fatty acids and other healthful compounds; therefore, the intake of purslane and/or its bioactive compounds could help to improve the health and function of the whole human organism. Accordingly, in this work it was analyzed and compared to the extractive capacity of the antioxidant component of purslane leaves obtained by solid-liquid extraction techniques such as: hot-maceration, maceration with ultrasound, rapid solid-liquid dynamic extraction using the Naviglio extractor, and a combination of two techniques (mix extraction). The chromatographic analysis by High Performance Liquid Chromatography (HPLC) of the methanolic extract of dried purslane leaves allowed the identification of various polyphenolic compounds for comparison with the standards. In addition, the properties of the different extracts were calculated on dry matter and the antioxidant properties of the total polyphenol components analyzed by the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay. The results showed that mix extraction was the most efficient compared to other techniques. In fact, it obtained a quantity of polyphenols amounting to 237.8 mg Gallic Acid Equivalents (GAE)/100 g of fresh weight, while in other techniques, the range varied from 60–160 mg GAE/100 g fresh weight. In addition, a qualitative analysis by Liquid Chromatography-Tandem Mass Spectrometry (LC/MS/MS) of the phenolic compounds present in the purslane leaves examined was carried out. The compounds were identified by comparison of their molecular weight, fragmentation pattern and retention time with those of standards, using the “Multiple Reaction Monitoring” mode (MRM). Therefore, this study allowed the re-evaluation of a little-known plant that possesses as its beneficial properties, a

Magnetic silica nanomaterials for solid-phase extraction combined with dispersive liquid-liquid microextraction of ultra-trace quantities of plasticizers

International Nuclear Information System (INIS)

Yamini, Yadollah; Faraji, Mohammad; Adeli, Mahnaz

2015-01-01

We are presenting surface modified magnetic silica nanoparticles (m-Si-NPs) for use in solid-phase extraction combined with dispersive liquid-liquid microextraction (DLLME). The m-Si-NPs were surface-functionalized with octadecyl groups to give a material for the extraction of the plasticizers dibutyl phthalate, di(2-ethylhexyl) adipate and di(2-ethylhexyl) phthalate from water samples. The functionalized m-Si-NPs were characterized by scanning electron microscopy, FTIR spectroscopy, thermal gravimetric analysis, and vibrating sample magnetometry. The results showed that the m-Si-NPs were well functionalized with octadecyl groups. The effects of various experimental variables on the extraction efficiencies were investigated. The analytes were quantified by GC/FID. Under optimal conditions, the calibration plots are linear in the range from 0.01 to 100 μg∙L -1 , and very high enrichment factors (mean value ∼20,000) were obtained. As a result of the high enrichment factors, the detection limits are as low as 2–3 ng∙L -1 . The method was successfully employed to the extraction of the plasticizers from (spiked) water samples, and recoveries are in the order of 93.9 to 106.7 %. The method is low cost, fast, and very sensitive (author)

Liquid-Liquid Extraction/Low-Temperature Purification (LLE/LTP Followed by Dispersive Solid-Phase Extraction (d-SPE Cleanup for Multiresidue Analysis in Palm Oil by LC-QTOF-MS

Directory of Open Access Journals (Sweden)

Elham Sobhanzadeh

2013-01-01

Full Text Available An evaluation of the extraction of multiresidue pesticides from palm oil by liquid-liquid extraction/low-temperature purification (LLE/LTP coupled with dispersive solid-phase extraction (d-SPE as the cleanup procedure with the determination by liquid chromatography mass spectrometry using electrospray as the ionization source (LC-ESI-MS was carried out. Optimization approaches were studied in terms of d-SPE to select efficiency of type and mass of adsorbents to obtain the highest recovery yield of pesticides and the lowest coextract fat residues in the final extract. The optimal conditions of d-SPE were obtained using 3 g of palm oil, 4 g anhydrous MgSO4, 150 mg of PSA, and 50 mg of GCB (PSA: GCB (3 : 1 w/w. Recovery study was performed at three concentration levels (25, 50, and 100 ng kg−1, yielding recovery rates between 71.8 and 112.4% except diuron with relative standard deviations of 3.2–15.1%. Detection and quantification limits were lower than 2.7 and 8.2 ng kg−1, respectively. The proposed method was successfully applied to the analysis of market-purchased palm oil samples from two different brands collected in Kuala Lumpur, showing its potential applicability and revealing the presence of some of the target species in the ng g−1 range.

Enhanced mass transfer during solid-liquid extraction of gamma-irradiated red beetroot

International Nuclear Information System (INIS)

Nayak, Chetan A.; Chethana, S.; Rastogi, N.K.; Raghavarao, K.S.M.S.

2006-01-01

The exposure to gamma-irradiation pretreatment increases cell wall permeabilization, resulting in loss of turgor pressure, which led to the increase of extractability of betanin from red beetroot. The degree of extraction of betanin was investigated using gamma irradiation as a pretreatment prior to the solid-liquid extraction process and compared with control beetroot samples. The beetroot subjected to different doses of gamma irradiation (2.5, 5.0, 7.5, 10.0 kGy) and control was dipped in an acetic acid medium (1% v/v) to extract the betanin. The diffusion coefficients for betanin as well as ionic component were estimated considering Fickian diffusion. The results indicated an increase in the diffusion coefficient of betanin (0.302x10 -9 -0.463x10 -9 m 2 /s) and ionic component (0.248x10 -9 -0.453x10 -9 m 2 /s) as the dose rate increased (from 2.5 to 10.0 kGy). The degradation constant was found to increase (0.050-0.079 min -1 ) with an increase gamma-irradiation doses (2.5-10.0 kGy), indicating lower stability of the betanin as compared to control sample at 65 deg. C

Comparison between different liquid-liquid and solid phase methods of extraction prior to the identification of the phenolic fraction present in olive oil washing wastewater from the two-phase olive oil extraction system

Directory of Open Access Journals (Sweden)

S. Jiménez-Herrera

2017-09-01

Full Text Available Phenolic compounds from olive mill wastewater (OMW, are characterized by a strong antioxidant activity. At the same time, they represent an environmental problem because they are difficult to degrade. The purpose of this work was to identify these biologically active compounds in the OMW from two-phase olive oil production in order to convert a polluting residue into a source of natural antioxidants. After optimizing the extraction process of phenolic compounds using liquid-liquid extraction (LLE and solid phase extraction (SPE methods, it was determined that the most appropriate sequence comprised a previous centrifugation to remove the lipid fraction, followed by liquid extraction with ethyl acetate or SPE. The most important compounds identified in olive oil washing wastewater (OOWW were tyrosol, hydroxytyrosol and succinic acid; whereas the ones in the wastewater derived from the washing of the olives (OWW were cresol, catechol, 4-methylcatechol, hydrocinnamic acid and p-hydroxy-hydrocinnamic acid.

Comparison between different liquid-liquid and solid phase methods of extraction prior to the identification of the phenolic fraction present in olive oil washing wastewater from the two-phase olive oil extraction system

International Nuclear Information System (INIS)

Jiménez-Herrera, S.; Ochando-Pulido, J.M.; Martínez-Ferez, A.

2017-01-01

Phenolic compounds from olive mill wastewater (OMW), are characterized by a strong antioxidant activity. At the same time, they represent an environmental problem because they are difficult to degrade. The purpose of this work was to identify these biologically active compounds in the OMW from two-phase olive oil production in order to convert a polluting residue into a source of natural antioxidants. After optimizing the extraction process of phenolic compounds using liquid-liquid extraction (LLE) and solid phase extraction (SPE) methods, it was determined that the most appropriate sequence comprised a previous centrifugation to remove the lipid fraction, followed by liquid extraction with ethyl acetate or SPE. The most important compounds identified in olive oil washing wastewater (OOWW) were tyrosol, hydroxytyrosol and succinic acid; whereas the ones in the wastewater derived from the washing of the olives (OWW) were cresol, catechol, 4-methylcatechol, hydrocinnamic acid and p-hydroxy-hydrocinnamic acid. [es

Determination of organophosphate flame retardants in soil and fish using ultrasound-assisted extraction, solid-phase clean-up, and liquid chromatography with tandem mass spectrometry.

Science.gov (United States)

Lorenzo, María; Campo, Julián; Picó, Yolanda

2018-03-22

A solid-liquid extraction method in combination with high-performance liquid chromatography and tandem mass spectrometry was developed and optimized for extraction and analysis of organophosphorus flame retardants in soil and fish. Methanol was chosen as the optimum extraction solvent, not only in terms of extraction efficiency, but also for its broader analyte coverage. The subsequent clean-up by solid-phase extraction is required to eliminate matrix coextractives and reduce matrix effects. Recoveries of the optimized method were 50-121% for soil and 47-123% for biota, both with high precision (RSDs solid-phase extraction cartridge clogging that increase variability and analysis time. The method was successfully applied for the determination of organophosphorus flame retardants in soil and fish from L'Albufera Natural Park (Valencia, Spain). Target compounds were detected in all soil and fish samples with values varying from 13.8 to 89.7 ng/g dry weight and from 3.3 to 53.0 ng/g wet weight, respectively. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simultaneous determination of phenolic compounds in Equisetum palustre L. by ultra high performance liquid chromatography with tandem mass spectrometry combined with matrix solid-phase dispersion extraction.

Science.gov (United States)

Wei, Zuofu; Pan, Youzhi; Li, Lu; Huang, Yuyang; Qi, Xiaolin; Luo, Meng; Zu, Yuangang; Fu, Yujie

2014-11-01

A method based on matrix solid-phase dispersion extraction followed by ultra high performance liquid chromatography with tandem mass spectrometry is presented for the extraction and determination of phenolic compounds in Equisetum palustre. This method combines the high efficiency of matrix solid-phase dispersion extraction and the rapidity, sensitivity, and accuracy of ultra high performance liquid chromatography with tandem mass spectrometry. The influential parameters of the matrix solid-phase dispersion extraction were investigated and optimized. The optimized conditions were as follows: silica gel was selected as dispersing sorbent, the ratio of silica gel to sample was selected to be 2:1 (400/200 mg), and 8 mL of 80% methanol was used as elution solvent. Furthermore, a fast and sensitive ultra high performance liquid chromatography with tandem mass spectrometry method was developed for the determination of nine phenolic compounds in E. palustre. This method was carried out within <6 min, and exhibited satisfactory linearity, precision, and recovery. Compared with ultrasound-assisted extraction, the proposed matrix solid-phase dispersion procedure possessed higher extraction efficiency, and was more convenient and time saving with reduced requirements on sample and solvent amounts. All these results suggest that the developed method represents an excellent alternative for the extraction and determination of active components in plant matrices. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dispersive solid-phase extraction followed by vortex-assisted dispersive liquid-liquid microextraction based on the solidification of a floating organic droplet for the determination of benzoylurea insecticides in soil and sewage sludge.

Science.gov (United States)

Peng, Guilong; He, Qiang; Mmereki, Daniel; Lu, Ying; Zhong, Zhihui; Liu, Hanyang; Pan, Weiliang; Zhou, Guangming; Chen, Junhua

2016-04-01

A novel dispersive solid-phase extraction combined with vortex-assisted dispersive liquid-liquid microextraction based on solidification of floating organic droplet was developed for the determination of eight benzoylurea insecticides in soil and sewage sludge samples before high-performance liquid chromatography with ultraviolet detection. The analytes were first extracted from the soil and sludge samples into acetone under optimized pretreatment conditions. Clean-up of the extract was conducted by dispersive solid-phase extraction using activated carbon as the sorbent. The vortex-assisted dispersive liquid-liquid microextraction based on solidification of floating organic droplet procedure was performed by using 1-undecanol with lower density than water as the extraction solvent, and the acetone contained in the solution also acted as dispersive solvent. Under the optimum conditions, the linearity of the method was in the range 2-500 ng/g with correlation coefficients (r) of 0.9993-0.9999. The limits of detection were in the range of 0.08-0.56 ng/g. The relative standard deviations varied from 2.16 to 6.26% (n = 5). The enrichment factors ranged from 104 to 118. The extraction recoveries ranged from 81.05 to 97.82% for all of the analytes. The good performance has demonstrated that the proposed methodology has a strong potential for application in the multiresidue analysis of complex matrices. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Isocratic Solid Phase Extraction-Liquid Chromatography (SPE-LC) Interfaced to High-Performance Tandem Mass Spectrometry for Rapid Protein Identification

DEFF Research Database (Denmark)

Hørning, Ole B; Kjeldsen, Frank; Theodorsen, Søren

2008-01-01

the isocratic solid phase extraction-liquid chromatography (SPE-LC) technology for rapid separation ( approximately 8 min) of simple peptide samples. We now extend these studies to demonstrate the potential of SPE-LC separation in combination with a hybrid linear ion trap-Orbitrap tandem mass spectrometer...

Dispersive solid phase extraction combined with ion-pair ultra high-performance liquid chromatography tandem mass spectrometry for quantification of nucleotides in Lactococcus lactis

DEFF Research Database (Denmark)

Magdenoska, Olivera; Martinussen, Jan; Thykær, Jette

2013-01-01

solid phase extraction with charcoal and subsequent analysis with ion-pair liquid chromatography coupled with electrospray ionization tandem mass spectrometry was established for quantification of intracellular pools of the 28 most important nucleotides. The method can handle extracts where cells leak...

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.

Solid phase extraction for removal of matrix effects in lipophilic marine toxin analysis by liquid chromatography-tandem mass spectrometry

NARCIS (Netherlands)

Gerssen, A.; McElhinney, M.; Mulder, P.P.J.; Bire, R.; Hess, P.; Boer, de J.

2009-01-01

The potential of solid phase extraction (SPE) clean-up has been assessed to reduce matrix effects (signal suppression or enhancement) in the liquid chromatography-tandem mass spectrometry (LC¿MS/MS) analysis of lipophilic marine toxins. A large array of ion-exchange, silica-based, and mixed-function

Solid phase extraction for removal of matrix effects in lipophilic marine toxin analysis by liquid chromatography-tandem mass spectrometry

NARCIS (Netherlands)

Gerssen, A.; McElhinney, A. M.; Mulder, P.P.J.; Bire, L.; Hess, P.; de Boer, J.

2009-01-01

The potential of solid phase extraction (SPE) clean-up has been assessed to reduce matrix effects (signal suppression or enhancement) in the liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of lipophilic marine toxins. A large array of ion-exchange, silica-based, and mixed-function

Amino acids separation with the tetracarboxylic derived of the para-ter-butylcalix[4]arene by means of solid-liquid extraction assisted with lanthanides

International Nuclear Information System (INIS)

Bernal R, R. del C.

2014-01-01

The tetracarboxylic derived of the para-ter-butylcalix[4]arene (B 4 ACEbL 4 ) does not exist commercially for what was synthesized and characterized at laboratory level. The separation of the L-tyrosine amino acid was studied by means of a solid-liquid extraction system with the B 4 ACEbL 4 as solid phase, in function of ph (2.5-7.5) and contact time (5 and 15 hours) to temperature of 15-17 grades C. Resulted that the ph and the contact time were decisive in the extraction percentage of water tyrosine. The lowest percentage was 49% to ph 4 and the highest percentage was 61% to ph 7.5 with 15 hours of contact. In a contact time of 5 hours the extraction was inferior to 32% (ph 4) and of 47% to ph 6.5. The europium effect (Eu (III)) was studied to ph acid in the tyrosine separation and was found that the tyrosine extraction is not increased neither decomposes in europium presence, this is simultaneously extracted by the calixarene but it does not enter in competition for the calixarene with the amino acid. The separate solid phases: calixarene-tyrosine was analyzed by Far infrared radiation (Fir), Mid-Infrared (Mir) spectroscopy and luminescence to check the tyrosine presence in the separate solids as well as the nature of the connection calixarene-tyrosine. In this way was possible to check the tyrosine presence and to propose the formed molecular species tyrosine-calixarene, those which interact mainly by means of hydrogen connections and Van der Waals forces. The liquid phases before and after the extraction were analyzed by UV-Vis spectrophotometry and luminescence. The Neutron activation analysis was used to determine the europium content in the solid and liquid phases of extractions in europium presence. The tyrosine degradation also shows dependence with the ph, obtaining 88% degradation to the 24 hours to ph 7.5, while to ph 3 is degraded the 54% of tyrosine present in the sample. The europium presence does not affect the tyrosine extraction but if its photo

[Simultaneous determination of 15 industrial synthetic dyes in condiment by solid phase extraction-high performance liquid chromatography].

Science.gov (United States)

Liu, Min; Li, Xiaolin; Bie, Wei; Wang, Minglin; Feng, Qian

2011-02-01

A new method was established for the determination of 15 industrial synthetic dyes in condiment by solid phase extraction-high performance liquid chromatography (SPE-HPLC). The samples were extracted by methanol-water (1:1, v/v) and purified by a solid phase extraction column. Then, the chromatographic separation was achieved on a Luna C18 column by linear gradient elution. The mobile phase was 10 mmol/L ammonium acetate-acetonitrile (containing 1% acetic acid). The results showed that the 15 industrial synthetic dyes can be separated efficiently. The recoveries of the 15 industrial synthetic dyes spiked in condiment were between 84.6% and 114.2% with the relative standard deviations of 0.9% - 10.3%. The limits of detection of this method was 0.05 - 0.18 mg/kg for the 15 industrial synthetic dyes. The method is simple, sensitive, accurate, repeatable and can be used for simultaneous determination of the 15 illegally added industrial synthetic dyes.

Applications of Liquid-Phase Microextraction in the Sample Preparation of Environmental Solid Samples

Directory of Open Access Journals (Sweden)

Helena Prosen

2014-05-01

Full Text Available Solvent extraction remains one of the fundamental sample preparation techniques in the analysis of environmental solid samples, but organic solvents are toxic and environmentally harmful, therefore one of the possible greening directions is its miniaturization. The present review covers the relevant research from the field of application of microextraction to the sample preparation of environmental solid samples (soil, sediments, sewage sludge, dust etc. published in the last decade. Several innovative liquid-phase microextraction (LPME techniques that have emerged recently have also been applied as an aid in sample preparation of these samples: single-drop microextraction (SDME, hollow fiber-liquid phase microextraction (HF-LPME, dispersive liquid-liquid microextraction (DLLME. Besides the common organic solvents, surfactants and ionic liquids are also used. However, these techniques have to be combined with another technique to release the analytes from the solid sample into an aqueous solution. In the present review, the published methods were categorized into three groups: LPME in combination with a conventional solvent extraction; LPME in combination with an environmentally friendly extraction; LPME without previous extraction. The applicability of these approaches to the sample preparation for the determination of pollutants in solid environmental samples is discussed, with emphasis on their strengths, weak points and environmental impact.

Applications of liquid-phase microextraction in the sample preparation of environmental solid samples.

Science.gov (United States)

Prosen, Helena

2014-05-23

Solvent extraction remains one of the fundamental sample preparation techniques in the analysis of environmental solid samples, but organic solvents are toxic and environmentally harmful, therefore one of the possible greening directions is its miniaturization. The present review covers the relevant research from the field of application of microextraction to the sample preparation of environmental solid samples (soil, sediments, sewage sludge, dust etc.) published in the last decade. Several innovative liquid-phase microextraction (LPME) techniques that have emerged recently have also been applied as an aid in sample preparation of these samples: single-drop microextraction (SDME), hollow fiber-liquid phase microextraction (HF-LPME), dispersive liquid-liquid microextraction (DLLME). Besides the common organic solvents, surfactants and ionic liquids are also used. However, these techniques have to be combined with another technique to release the analytes from the solid sample into an aqueous solution. In the present review, the published methods were categorized into three groups: LPME in combination with a conventional solvent extraction; LPME in combination with an environmentally friendly extraction; LPME without previous extraction. The applicability of these approaches to the sample preparation for the determination of pollutants in solid environmental samples is discussed, with emphasis on their strengths, weak points and environmental impact.

Evaluation of ionic liquids supported on silica as a sorbent for fully automated online solid-phase extraction with LC-MS determination of sulfonamides in bovine milk samples.

Science.gov (United States)

da Silva, Meire Ribeiro; Mauro Lanças, Fernando

2018-03-10

Sulfonamides are antibiotics widely used in the treatment of diseases in dairy cattle. However, their indiscriminate use for disease control may lead to their presence in tissues and milk and their determination requires a sample preparation step as part of an analytical approach. Among the several sample preparation techniques available, those based upon the use of sorptive materials have been widely employed. Recently, the application of ionic liquids immobilized on silica surfaces or polymeric materials has been evaluated for such an application. This manuscript addresses the evaluation of silica-based ionic liquid obtained by a sol-gel synthesis process by basic catalysis as sorbent for online solid-phase extraction with liquid chromatography and electrospray ionization time-of-flight mass spectrometry for sulfonamides determination. Infrared vibrational spectroscopy confirmed the presence of the ionic liquid on the silica surface, suggesting that the ionic liquid was anchored on to the silica surface. Other sorbents varying the ionic liquid alkyl chain were also synthesized and evaluated by off-line solid-phase extraction in the sulfonamide extraction. As the length of the alkyl chain increased, the amount of extracted sulfonamides decreased, possibly due to a decrease in the electrostatic interaction caused by the reduction in the polarity, as well as the presence of a hexafluorophosphate anion that increases the hydrophobic character of the material. The use of 1-butyl-3-methylimidazolium hexafluorophosphate as a selective ionic liquid sorbent enabled the isolation and sulfonamide preconcentration in bovine milk by online solid-phase extraction with liquid chromatography and electrospray ionization time-of-flight mass spectrometry. The limit of quantification for the method developed was 5-7, 5 μg/mL, with extraction recoveries ranging between 74 and 93% and intra- and interassay between 1.5-12.5 and 2.3-13.1, respectively. © 2018 WILEY-VCH Verlag Gmb

Mycoestrogen determination in cow milk: Magnetic solid-phase extraction followed by liquid chromatography and tandem mass spectrometry analysis.

Science.gov (United States)

Capriotti, Anna Laura; Cavaliere, Chiara; Foglia, Patrizia; La Barbera, Giorgia; Samperi, Roberto; Ventura, Salvatore; Laganà, Aldo

2016-12-01

Recently, magnetic solid-phase extraction has gained interest because it presents various operational advantages over classical solid-phase extraction. Furthermore, magnetic nanoparticles are easy to prepare, and various materials can be used in their synthesis. In the literature, there are only few studies on the determination of mycoestrogens in milk, although their carryover in milk has occurred. In this work, we wanted to develop the first (to the best of our knowledge) magnetic solid-phase extraction protocol for six mycoestrogens from milk, followed by liquid chromatography and tandem mass spectrometry analysis. Magnetic graphitized carbon black was chosen as the adsorbent, as this carbonaceous material, which is very different from the most diffuse graphene and carbon nanotubes, had already shown selectivity towards estrogenic compounds in milk. The graphitized carbon black was decorated with Fe 3 O 4 , which was confirmed by the characterization analyses. A milk deproteinization step was avoided, using only a suitable dilution in phosphate buffer as sample pretreatment. The overall process efficiency ranged between 52 and 102%, whereas the matrix effect considered as signal suppression was below 33% for all the analytes even at the lowest spiking level. The obtained method limits of quantification were below those of other published methods that employ classical solid-phase extraction protocols. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Solid-phase extraction followed by dispersive liquid-liquid microextraction for the sensitive determination of ecstasy compounds and amphetamines in biological samples

Directory of Open Access Journals (Sweden)

H. A. Mashayekhi

2014-09-01

Full Text Available A novel approach for the determination of ecstasy and amphetamines (3,4-methylenedioxymethylamphetamine (MDMA, Ecstasy, 3,4-methylenedioxyamphetamine (MDA, 3,4-methylenedioxyethylamphetamine (MDEA and 3,4-methylenedioxypropylamphetamine (MDPA in biological samples is presented. The analytes were extracted from the matrix and transferred to a small volume of a high density, water insoluble solvent using solid-phase extraction (SPE followed by dispersive liquid-liquid microextraction (DLLME. This combination not only resulted in a high enrichment factor, but also it could be used in complex matrices (biological samples. Some important extraction parameters, such as sample solution flow rate, sample pH, type and volume of extraction and disperser solvents as well as the salt addition, were studied and optimized. Under the optimized conditions, the calibration graphs were linear in the range of 0.5-500 µg L-1 and 1.0-500 µg L-1 with detection limits in the range of 0.1-0.3 µg L-1 and 0.2-0.7 µg L-1 in urine and plasma samples, respectively. The results showed that SPE-DLLME is a suitable method for the determination of ecstasy components and amphetamines in biological and water samples. DOI: http://dx.doi.org/10.4314/bcse.v28i3.3

Solid/liquid extraction equilibria of phenolic compounds with trioctylphosphine oxide impregnated in polymeric membranes.

Science.gov (United States)

Praveen, Prashant; Loh, Kai-Chee

2016-06-01

Trioctylphosphine oxide based extractant impregnated membranes (EIM) were used for extraction of phenol and its methyl, hydroxyl and chloride substituted derivatives. The distribution coefficients of the phenols varied from 2 to 234, in the order of 1-napthol > p-chlorophenol > m-cresol > p-cresol > o-cresol > phenol > catechol > pyrogallol > hydroquinone, when initial phenols loadings was varied in 100-2000 mg/L. An extraction model, based on the law of mass action, was formulated to predict the equilibrium distribution of the phenols. The model was in excellent agreement (R(2) > 0.97) with the experimental results at low phenols concentrations ( 0.95), which signified high mass transfer resistance in the EIMs. Examination of the effects of ring substitution on equilibrium, and bivariate statistical analysis between the amounts of phenols extracted into the EIMs and factors affecting phenols interaction with TOPO, indicated the dominant role of hydrophobicity in equilibrium determination. These results improve understanding of the solid/liquid equilibrium process between phenols and the EIMs, and these will be useful in designing phenol recovery process from wastewater. Copyright © 2016 Elsevier Ltd. All rights reserved.

Headspace solid-phase microextraction (HS-SPME) and liquid-liquid extraction (LLE): comparison of the performance in classification of ecstasy tablets. Part 2.

Science.gov (United States)

Bonadio, Federica; Margot, Pierre; Delémont, Olivier; Esseiva, Pierre

2008-11-20

Headspace solid-phase microextraction (HS-SPME) is assessed as an alternative to liquid-liquid extraction (LLE) currently used for 3,4-methylenedioxymethampethamine (MDMA) profiling. Both methods were compared evaluating their performance in discriminating and classifying samples. For this purpose 62 different seizures were analysed using both extraction techniques followed by gas chromatography-mass spectroscopy (GC-MS). A previously validated method provided data for HS-SPME, whereas LLE data were collected applying a harmonized methodology developed and used in the European project CHAMP. After suitable pre-treatment, similarities between sample pairs were studied using the Pearson correlation. Both methods enable to distinguish between samples coming from the same pre-tabletting batches and samples coming from different pre-tabletting batches. This finding emphasizes the use of HS-SPME as an effective alternative to LLE, with additional advantages such as sample preparation and a solvent-free process.

DNA extraction on bio-chip: history and preeminence over conventional and solid-phase extraction methods.

Science.gov (United States)

Ayoib, Adilah; Hashim, Uda; Gopinath, Subash C B; Md Arshad, M K

2017-11-01

This review covers a developmental progression on early to modern taxonomy at cellular level following the advent of electron microscopy and the advancement in deoxyribonucleic acid (DNA) extraction for expatiation of biological classification at DNA level. Here, we discuss the fundamental values of conventional chemical methods of DNA extraction using liquid/liquid extraction (LLE) followed by development of solid-phase extraction (SPE) methods, as well as recent advances in microfluidics device-based system for DNA extraction on-chip. We also discuss the importance of DNA extraction as well as the advantages over conventional chemical methods, and how Lab-on-a-Chip (LOC) system plays a crucial role for the future achievements.

A combination of solid-phase extraction and dispersive solid-phase extraction effectively reduces the matrix interference in liquid chromatography-ultraviolet detection during pyraclostrobin analysis in perilla leaves.

Science.gov (United States)

Farha, Waziha; Rahman, Md Musfiqur; Abd El-Aty, A M; Jung, Da-I; Kabir, Md Humayun; Choi, Jeong-Heui; Kim, Sung-Woo; Im, So Jeong; Lee, Young-Jun; Shin, Ho-Chul; Kwon, Chan-Hyeok; Son, Young-Wook; Lee, Kang-Bong; Shim, Jae-Han

2015-12-01

Perilla leaves contain many interfering substances; thus, it is difficult to protect the analytes during identification and integration. Furthermore, increasing the amount of sample to lower the detection limit worsens the situation. To overcome this problem, we established a new method using a combination of solid-phase extraction and dispersive solid-phase extraction to analyze pyraclostrobin in perilla leaves by liquid chromatography with ultraviolet absorbance detection. The target compound was quantitated by external calibration with a good determination coefficient (R(2) = 0.997). The method was validated (in triplicate) with three fortification levels, and 79.06- 89.10% of the target compound was recovered with a relative standard deviation <4. The limits of detection and quantification were 0.0033 and 0.01 mg/kg, respectively. The method was successfully applied to field samples collected from two different areas at Gwangju and Muan. The decline in the resiudue concentrations was best ascribed to a first-order kinetic model with half-lives of 5.7 and 4.6 days. The variation between the patterns was attributed to humidity. Copyright © 2015 John Wiley & Sons, Ltd.

Determination of caffeoylquinic acids in feed and related products by focused ultrasound solid-liquid extraction and ultra-high performance liquid chromatography-mass spectrometry.

Science.gov (United States)

Tena, M T; Martínez-Moral, M P; Cardozo, P W

2015-06-26

A method to determine caffeoylquinic acids (CQAs) in three sources (herbal extract, feed additive and finished feed) using for the first time focused ultrasound solid-liquid extraction (FUSLE) followed by ultra-high performance liquid chromatography (UPLC) coupled to quadrupole-time of flight mass spectrometry is presented. Pressurized liquid extraction (PLE) was also tested as extraction technique but it was discarded because cynarin was not stable under temperature values used in PLE. The separation of the CQAs isomers was carried out in only seven minutes. FUSLE variables such as extraction solvent, power and time were optimized by a central composite design. Under optimal conditions, FUSLE extraction was performed with 8mL of an 83:17 methanol-water mixture for 30s at a power of 60%. Only two extraction steps were found necessary to recover analytes quantitatively. Sensitivity, linearity, accuracy and precision were established. Matrix effect was studied for each type of sample. It was not detected for mono-CQAs, whereas the cynarin signal was strongly decreased due to ionization suppression in presence of matrix components; so the quantification by standard addition was mandatory for the determination of di-caffeoylquinic acids. Finally, the method was applied to the analysis of herbal extracts, feed additives and finished feed. In all samples, chlorogenic acid was the predominant CQA, followed by criptochlorogenic acid, neochlorogenic acid and cynarin. The method allows an efficient determination of chlorogenic acid with good recovery rates. Therefore, it may be used for screening of raw material and for process and quality control in feed manufacture. Copyright © 2015 Elsevier B.V. All rights reserved.

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.

Determination of the Antibiotic Oxytetracycline in Commercial Milk by Solid-Phase Extraction: A High-Performance Liquid Chromatography (HPLC) Experiment for Quantitative Instrumental Analysis

Science.gov (United States)

Mei-Ratliff, Yuan

2012-01-01

Trace levels of oxytetracylcine spiked into commercial milk samples are extracted, cleaned up, and preconcentrated using a C[subscript 18] solid-phase extraction column. The extract is then analyzed by a high-performance liquid chromatography (HPLC) instrument equipped with a UV detector and a C[subscript 18] column (150 mm x 4.6 mm x 3.5 [mu]m).…

Two-dimensional solid-phase extraction strategy for the selective enrichment of aminoglycosides in milk.

Science.gov (United States)

Shen, Aijin; Wei, Jie; Yan, Jingyu; Jin, Gaowa; Ding, Junjie; Yang, Bingcheng; Guo, Zhimou; Zhang, Feifang; Liang, Xinmiao

2017-03-01

An orthogonal two-dimensional solid-phase extraction strategy was established for the selective enrichment of three aminoglycosides including spectinomycin, streptomycin, and dihydrostreptomycin in milk. A reversed-phase liquid chromatography material (C 18 ) and a weak cation-exchange material (TGA) were integrated in a single solid-phase extraction cartridge. The feasibility of two-dimensional clean-up procedure that experienced two-step adsorption, two-step rinsing, and two-step elution was systematically investigated. Based on the orthogonality of reversed-phase and weak cation-exchange procedures, the two-dimensional solid-phase extraction strategy could minimize the interference from the hydrophobic matrix existing in traditional reversed-phase solid-phase extraction. In addition, high ionic strength in the extracts could be effectively removed before the second dimension of weak cation-exchange solid-phase extraction. Combined with liquid chromatography and tandem mass spectrometry, the optimized procedure was validated according to the European Union Commission directive 2002/657/EC. A good performance was achieved in terms of linearity, recovery, precision, decision limit, and detection capability in milk. Finally, the optimized two-dimensional clean-up procedure incorporated with liquid chromatography and tandem mass spectrometry was successfully applied to the rapid monitoring of aminoglycoside residues in milk. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Analysis of trace dicyandiamide in stream water using solid phase extraction and liquid chromatography UV spectrometry.

Science.gov (United States)

Qiu, Huidong; Sun, Dongdi; Gunatilake, Sameera R; She, Jinyan; Mlsna, Todd E

2015-09-01

An improved method for trace level quantification of dicyandiamide in stream water has been developed. This method includes sample pretreatment using solid phase extraction. The extraction procedure (including loading, washing, and eluting) used a flow rate of 1.0mL/min, and dicyandiamide was eluted with 20mL of a methanol/acetonitrile mixture (V/V=2:3), followed by pre-concentration using nitrogen evaporation and analysis with high performance liquid chromatography-ultraviolet spectroscopy (HPLC-UV). Sample extraction was carried out using a Waters Sep-Pak AC-2 Cartridge (with activated carbon). Separation was achieved on a ZIC(®)-Hydrophilic Interaction Liquid Chromatography (ZIC-HILIC) (50mm×2.1mm, 3.5μm) chromatography column and quantification was accomplished based on UV absorbance. A reliable linear relationship was obtained for the calibration curve using standard solutions (R(2)>0.999). Recoveries for dicyandiamide ranged from 84.6% to 96.8%, and the relative standard deviations (RSDs, n=3) were below 6.1% with a detection limit of 5.0ng/mL for stream water samples. Copyright © 2015. Published by Elsevier B.V.

Recovery of Steroidal Alkaloids from Potato Peels Using Pressurized Liquid Extraction

Directory of Open Access Journals (Sweden)

Mohammad B. Hossain

2015-05-01

Full Text Available A higher yield of glycoalkaloids was recovered from potato peels using pressurized liquid extraction (1.92 mg/g dried potato peels compared to conventional solid–liquid extraction (0.981 mg/g dried potato peels. Response surface methodology deduced the optimal temperature and extracting solvent (methanol for the pressurized liquid extraction (PLE of glycoalkaloids as 80 °C in 89% methanol. Using these two optimum PLE conditions, levels of individual steroidal alkaloids obtained were of 597, 873, 374 and 75 µg/g dried potato peel for α-solanine, α-chaconine, solanidine and demissidine respectively. Corresponding values for solid liquid extraction were 59%, 46%, 40% and 52% lower for α-solanine, α-chaconine, solanidine and demissidine respectively.

Application of liquid-liquid extraction in uranium hydrometallurgy (Paper No. : V-1)

Energy Technology Data Exchange (ETDEWEB)

Murthy, T K.S.; Koppiker, K S

1979-01-01

Uranium recovery from the ores is carried out exclusively by hydrometallurgical techniques. The initial solubilisation of uranium is achieved by either sodium carbonate or sulphuric acid leaching, the latter being more common. Further purification and upgrading of uranium from the sulphate liquors is carried out by an ion-exchange process. Solid resin type anion exchangers or liquid ion-exchangers are employed. The processing of uranium liquors is, perhaps, the first major application of liquid-liquid extraction in metal recovery. Organophosphoric acids were initially used but later the long-chain aliphatic amines have superseded them. The amine extraction system has been widely studied and several variations are now known. Chloride, nitrate, carbonate or sulphate or acid stripping can be used for getting back the uranium into the aqueous phase. Combination of ion exchange (resin type) and solvent extraction processes called Eluex processes are developed for special applications. Studies have also been made of solvent extraction of uranium from leach pulps instead of clear liquors. Tributylphosphate has found wide application in the refining of uranium concentrates to meet the stringent needs of nuclear purity. liquid-liquid extraction is, perhaps, the only successful technique for the recovery of uranium, as by-product, from wet-process phosphoric acid. This has opened up a new source of uranium.

MOLECULARLY IMPRINTED SOLID PHASE EXTRACTION FOR TRACE ANALYSIS OF DIAZINON IN DRINKING WATER

Directory of Open Access Journals (Sweden)

M. Rahiminejad ، S. J. Shahtaheri ، M. R. Ganjali ، A. Rahimi Forushani ، F. Golbabaei

2009-04-01

Full Text Available Amongst organophosphate pesticides, the one most widely used and common environmental contaminant is diazinon; thus methods for its trace analysis in environmental samples must be developed. Use of diazinon imprinted polymers such as sorbents in solid phase extraction, is a prominent and novel application area of molecular imprinted polymers. For diazinon extraction, high performance liquid chromatography analysis was demonstrated in this study. During optimization of the molecular imprinted solid phase extraction procedure for efficient solid phase extraction of diazinon, Plackett-Burman design was conducted. Eight experimental factors with critical influence on molecular imprinted solid phase extraction performance were selected, and 12 different experimental runs based on Plackett-Burman design were carried out. The applicability of diazinon imprinted polymers as the sorbent in solid phase extraction, presented obtained good recoveries of diazinon from LC-grade water. An increase in pH caused an increase in the recovery on molecular imprinted solid phase extraction. From these results, the optimal molecular imprinted solid phase extraction procedure was as follows: solid phase extraction packing with 100 mg diazinon imprinted polymers; conditioning with 5 mL of methanol and 6 mL of LC-grade water; sample loading containing diazinon (pH=10; washing with 1 mL of LC-grade water, 1 mL LC- grade water containing 30% acetonitrile and 0.5 mL of acetonitrile, respectively; eluting with 1 mL of methanol containing 2% acetic acid. The percentage recoveries obtained by the optimized molecular imprinted solid phase extraction were more than 90% with drinking water spiked at different trace levels of diazinon. Generally speaking, the molecular imprinted solid phase extraction procedure and subsequent high performance liquid chromatography analysis can be a relatively fast and proper approach for qualitative and quantitative analysis of diazinon in

Analysis of Free Amino Acids in Different Extracts of Orthosiphon stamineus Leaves by High-Performance Liquid Chromatography Combined with Solid-Phase Extraction.

Science.gov (United States)

Shafaei, Armaghan; Halim, Nor Hidayah Ab; Zakaria, Norhidayah; Ismail, Zhari

2017-10-01

Orthosiphon stamineus (OS) Benth is a medicinal plant and native in Southeast Asia. Previous studies have shown that OS leaves possess antioxidant, cytotoxic, diuretic, antihypertensive, and uricosuric effects. These beneficial effects have been attributed to the presence of primary and secondary metabolites such as polyphenols, amino acids, and flavonoids. To develop and validate an high-performance liquid chromatography (HPLC)-diode array detector (DAD) method combined with solid-phase extraction that involves precolumn derivatization with O -phthaladehyde for simultaneous analysis of free amino acids in OS leaves extracts. OS leaves were extracted with water (OS-W), ethanol (OS-E), methanol (OS-M), 50% ethanol (OS-EW), and 50% methanol (OS-MW). The extracts were treated by C18 cartridge before derivatization, resulting in great improvement of separation by Zorbox Eclipse XDB-C 18 column. The HPLC-DAD method was successfully developed and validated for analyzing the contents of free amino acids in OS extracts. The results showed that l-aspartic acid with 0.93 ± 0.01 nmol/mg was the major free amino acid in OS-W extract. However, in OS-E, OS-M, OS-EW, and OS-MW, l-glutamic acid with 3.53 ± 0.16, 2.17 ± 0.10, 4.01 ± 0.12, and 2.49 ± 0.12 nmol/mg, respectively, was the major free amino acid. Subsequently, l-serine, which was detected in OS-W, OS-E, and OS-M, was the minor free amino acid with 0.33 ± 0.02, 0.12 ± 0.01, and 0.06 ± 0.01 nmol/mg, respectively. However, l-threonine with 0.26 ± 0.02 and 0.19 ± 0.08 nmol/mL in OS-EW and OS-MW, respectively, had the lowest concentration compared with other amino acid components. All validation parameters of the developed method indicate that the method is reliable and efficient to simultaneously determine the free amino acids content for routine analysis of OS extracts. The HPLC-DAD method combined with solid phase extraction was successfully developed and validated for simultaneous determination and

Liquid and solid self-microemulsifying drug delivery systems for improving the oral bioavailability of andrographolide from a crude extract of Andrographis paniculata.

Science.gov (United States)

Sermkaew, Namfa; Ketjinda, Wichan; Boonme, Prapaporn; Phadoongsombut, Narubodee; Wiwattanapatapee, Ruedeekorn

2013-11-20

The purpose of this study was to develop self-microemulsifying formulations of an Andrographis paniculata extract in liquid and pellet forms for an improved oral delivery of andrographolide. The optimized liquid self-microemulsifying drug delivery system (SMEDDS) was composed of A. paniculata extract (11.1%), Capryol 90 (40%), Cremophor RH 40 (40%) and Labrasol (8.9%). This liquid SMEDDS was further adsorbed onto colloidal silicon dioxide and microcrystalline cellulose, and converted to SMEDDS pellets by the extrusion/spheronization technique. The microemulsion droplet sizes of the liquid and pellet formulations after dilution with water were in the range of 23.4 and 30.3 nm. The in vitro release of andrographolide from the liquid SMEDDS and SMEDDS pellets was 97.64% (SD 1.97%) and 97.74% (SD 3.36%) within 15 min, respectively while the release from the initial extract was only 10%. The oral absorption of andrographolide was determined in rabbits. The C(max) value of andrographolide from the A. paniculata extract liquid SMEDDS and SMEDDS pellet formulations (equivalent to 17.5mg/kg of andrographolide) was 6-fold and 5-fold greater than the value from the initial extract in aqueous suspension (equivalent to 35 mg/kg of andrographolide), respectively. In addition, the AUC(0-12h) was increased 15-fold by the liquid SMEDDS and 13-fold by the SMEDDS pellets compared to the extract in aqueous suspension, respectively. The results clearly indicated that the liquid and solid SMEDDS could be effectively used to improve the dissolution and oral bioavailability that would also enable a reduction in the dose of the poorly water soluble A. paniculata extract. Copyright © 2013 Elsevier B.V. All rights reserved.

Analysis of lignans in Magnoliae Flos by turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry.

Science.gov (United States)

Zhou, Xuan; Chen, Cen; Ye, Xiaolan; Song, Fenyun; Fan, Guorong; Wu, Fuhai

2016-04-01

In this study, a method coupling turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry was developed for analyzing the lignans in Magnoliae Flos. By the online pretreatment of turbulent flow chromatography solid-phase extraction, the impurities removal and analytes concentration were automatically processed, and the lignans were separated rapidly and well. Seven lignans of Magnoliae Flos including epieudesmin, magnolin, 1-irioresinol-B-dimethyl ether, epi-magnolin, fargesin aschantin, and demethoxyaschantin were identified by comparing their retention behavior, UV spectra, and mass spectra with those of reference substances or literature data. The developed method was validated, and the good results showed that the method was not only automatic and rapid, but also accurate and reliable. The turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry method holds a high potential to become an effective method for the quality control of lignans in Magnoliae Flos and a useful tool for the analysis of other complex mixtures. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Quantification of four ionophores in soil, sediment and manure using pressurised liquid extraction

DEFF Research Database (Denmark)

Bak, Søren Alex; Hansen, Martin; Pedersen, Kenneth Munk

2013-01-01

A multi-residue pressurised liquid extraction (PLE) methodology has been established for the determination of the four ionophores: lasalocid, monensin, salinomycin and narasin in solid environmental matrices. The PLE methodology is combined with solid phase extraction as clean-up using liquid...... chromatography coupled to tandem mass spectrometry applying electrospray ionisation for detection. The samples were freeze-dried prior to extraction. The absolute recoveries for soil and sediment ranged from 71 to 123% (relative standard deviation (RSDs) below 16%) and in the range 94-133% (RSDs 9...

A novel extraction technique based on carbon nanotubes reinforced hollow fiber solid/liquid microextraction for the measurement of piroxicam and diclofenac combined with high performance liquid chromatography.

Science.gov (United States)

Song, Xin-Yue; Shi, Yan-Ping; Chen, Juan

2012-10-15

A novel design of carbon nanotubes reinforced hollow fiber solid/liquid phase microextraction (CNTs-HF-SLPME) was developed to determine piroxicam and diclofenac in different real water samples. Functionalized multi-walled carbon nanotubes (MWCNTs) were held in the pores of hollow fiber with sol-gel technology. The pores and lumen of carbon nanotubes reinforced hollow fiber were subsequently filled with a μL volume of organic solvent (1-octanol), and then the whole assembly was used for the extraction of the target analytes in direct immersion sampling mode. The target analytes were extracted from the sample by two extractants, one of which is organic solvent placed inside the pores and lumen of hollow fiber and the other one is CNTs held in the pores of hollow fiber. After extraction, the analytes were desorbed in acetonitrile and analyzed using high performance liquid chromatography. This novel extraction mode showed more excellent extraction performance in comparison with conventional hollow fiber liquid microextraction (without adding CNTs) and carbon nanotubes reinforced hollow fiber solid microextraction (CNTs held in the pores of hollow fiber, but no organic solvents placed inside the lumen of hollow fiber) under the respective optimum conditions. This method provided 47- and 184-fold enrichment factors for piroxicam and diclofenac, respectively, good inter-fiber repeatability and batch-to-batch reproducibility. Linearity was observed in the range of 20-960 μg L(-1) for piroxicam, and 10-2560 μg L(-1) for diclofenac, with correlation coefficients of 0.9985 and 0.9989, respectively. The limits of detection were 4.58 μg L(-1) for piroxicam and 0.40 μg L(-1) for diclofenac. Copyright © 2012 Elsevier B.V. All rights reserved.

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.

ON-SITE SOLID-PHASE EXTRACTION AND LABORATORY ...

Science.gov (United States)

Fragrance materials such as synthetic musks in aqueous samples, are normally determined by gas chromatography/mass spectrometry in the selected ion monitoring (SIM) mode to provide maximum sensitivity after liquid-liquid extraction of I -L samples. Full-scan mass spectra are required to verify that a target analyte has been found by comparison with the mass spectra of fragrance compounds in the NIST mass spectral library. A I -L sample usually provides insufficient analyte for full scan data acquisition. This paper describes an on-site extraction method developed at the U.S. Environmental Protection Agency (USEPA)- Las Vegas Nevada - for synthetic musks from 60 L of wastewater effluent. Such a large sample volume permits high-quality, full-scan mass spectra to be obtained for a wide array of synthetic musks. Quantification of these compounds was achieved from the full-scan data directly, without the need to acquire SIM data. The detection limits obtained with this method are an order of magnitude lower than those obtained from liquid-liquid and other solid phase extraction methods. This method is highly reproducible, and recoveries ranged from 80 to 97% in spiked sewage treatment plant effluent. The high rate of sorbent-sample mass transfer eliminated the need for a methanolic activation step, which reduced extraction time, labor, and solvent use, More samples could be extracted in the field at lower cost. After swnple extraction, the light- weight cartridges ar

Study of molecularly imprinted solid-phase extraction of gonyautoxins 2,3 in the cultured dinoflagellate Alexandrium tamarense by high-performance liquid chromatography with fluorescence detection

International Nuclear Information System (INIS)

Lian, Zi-Ru; Wang, Jiang-Tao

2013-01-01

A highly selective sample cleanup procedure combined with molecularly imprinted solid-phase extraction (MISPE) was developed for the isolation of gonyautoxins 2,3 (GTX2,3) from Alexandrium tamarense sample. The molecularly imprinted polymer microspheres (MIPMs) were prepared by suspension polymerization using caffeine as the dummy template molecule, methacrylic acid as the functional monomer, ethylene glycol dimethacrylate as the cross-linker and polyvinyl alcohol as the dispersive reagent. The polymer microspheres were used as a selective sorbent for the solid-phase extraction of gonyautoxins 2,3. An off-line MISPE method followed by high-performance liquid chromatography (HPLC) with fluorescence detection for the analysis of gonyautoxins 2,3 was established. Finally, the extract samples from Alexandrium tamarense were analyzed. The results showed the imprinted polymer microspheres exhibited high affinity and selectivity for gonyautoxins 2,3. The interference matrix in the extract were obviously cleaned by MISPE and the extraction efficiency of gonyautoxins 2,3 in the sample ranged from 81.74% to 85.86%. -- Graphical abstract: This is the SEM photograph of molecularly imprinted polymer microspheres (MIPMs). MIPMs were prepared by suspension polymerization and used as selective sorbents for the solid-phase extraction of gonyautoxins 2,3. An off-line MISPE method followed by high-performance liquid chromatography with fluorescence detection for the analysis of gonyautoxins 2,3 was established. The extract samples from Alexandrium tamarense were analyzed by molecularly imprinted solid-phase extraction. Highlights: •The molecularly imprinted polymer microspheres (MIPMs) for GTX2,3 were prepared. •The characteristics and regeneration property of MIPMs were studied. •An off-line method using MIPMs as solid-phase extraction (SPE) sorbents was developed. •GTX2,3 from Alexandrium tamarense extract was successfully isolated by MIPMs-SPE. -- MIPMs for GTX2,3 were

Combination of solid-phase extraction with dispersive liquid-liquid microextraction followed by GC-MS for determination of pesticide residues from water, milk, honey and fruit juice.

Science.gov (United States)

Shamsipur, Mojtaba; Yazdanfar, Najmeh; Ghambarian, Mahnaz

2016-08-01

In this work, an effective preconcentration method for the extraction and determination of traces of multi-residue pesticides was developed using solid-phase extraction (SPE) coupled with dispersive liquid-liquid microextraction and gas chromatography-mass spectrometry (GC-MS). Variables affecting the performance of both extraction steps such as type and volume of elution and extraction solvents, breakthrough volume, salt addition, extraction time were thoroughly investigated. The proposed method resulted in good linearities (R(2)>0.9915) over the ranges of 1-10,000ngkg(-1), limits of detection (LODs) in the range of 0.5-1.0ngkg(-1) at S/N=3, and precision of RSD% of ⩽11.8. Under optimal conditions, the preconcentration factors were obtained in the range of 2362-10,593 for 100mL sample solutions. Comparison of the proposed method with other ones demonstrated that SPE-DLLME method provides higher extraction efficiency and larger preconcentration factor for determination of pesticides residues. Further, it is simple, inexpensive, highly sensitive, and can be successfully applied to separation, preconcentration and determination of the pesticides (and other noxious materials) in different real food samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

An Experimental Design Approach for the Analysis of Liquid Phase Products in Water for Hydrogenolysis of Glycerol using Immersed Solid-Phase Micro extraction

International Nuclear Information System (INIS)

Noraini Hamzah; Rozita Osman; Noraini Hamzah; Mohd Ambar Yarmo

2013-01-01

In this study, a response surface methodology (RSM) was applied to optimize the immersed-solid-phase micro extraction (immersed-SPME) conditions for the first time using a polyacrylate (PA) coated fiber. This was to determine liquid phase compounds in water for hydrogenolysis reaction of glycerol. There are a three-factor response surface experimental design was used to evaluate the interactive effects of extraction temperature (30-70 degree Celsius), extraction time (10-30 minutes) and desorption time (2-18 minutes) on the analysis of liquid phase compounds in water for hydrogenolysis of glycerol using immersed-solid-phase micro extraction (immersed-SPME). The extraction conditions using immersed-SPME were optimized in order to achieve high enrichment of the analytes from aqueous samples. The isolated compounds from the SPME fiber were desorbed and separated on a capillary polar column of a gas chromatography-flame ionization detector (GC-FID). The extraction time and desorption time were found significant in increasing the amount of glycerol in aqueous hydrogenolysis of glycerol. Nevertheless, the effect of extraction temperature was not significant. In terms of interactions between the effects, the relation between extraction temperature and extraction time was the most significant. The optimised immersed-SPME conditions were at extraction temperature of 27 degree Celsius, extraction time of 30 minutes and 15 minutes of desorption time. Thus, the application of SPME was found to be a rapid and effective technique in the determination of glycerol and propylene glycol compounds in aqueous hydrogenolysis glycerol. (author)

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.

Determination of trace bisphenol A in environmental water by high-performance liquid chromatography using magnetic reduced graphene oxide based solid-phase extraction coupled with dispersive liquid-liquid microextraction.

Science.gov (United States)

Li, Danping; Ma, Xiaoguo; Wang, Rui; Yu, Yumian

2017-02-01

Bisphenol A (BPA), an endocrine-disrupting chemical, has received much attention from researchers and the general public. In this paper, a novel method of determining BPA at trace levels was developed, using magnetic reduced graphene oxide (rGO-Fe 3 O 4 )-based solid-phase extraction coupled with dispersive liquid-liquid microextraction (DLLME), followed by high-performance liquid chromatographic determination. The rGO-Fe 3 O 4 was prepared and then characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, and vibrating sample magnetometry. The greatest saturation magnetization of rGO-Fe 3 O 4 was up to 43.8 emu g -1 , which allowed rapid isolation of the rGO-Fe 3 O 4 from solutions upon applying an appropriate magnetic field. The effects of solution pH, adsorbent amount, type and volume of eluent and extraction solvent, extraction time, and salt concentration on the extraction efficiency of BPA were examined and optimized. Under the optimum conditions, an enrichment factor of 5217 and an LOD of 0.01 μg L -1 for BPA were obtained. The reusability of rGO-Fe 3 O 4 for at least 12 repeated cycles without any significant decrease in the extraction recovery of BPA was demonstrated. The proposed method was applied to the determination of BPA in different real water samples, with relative recoveries of 84.8-104.9 % and RSDs of 0.8-8.3 % in the spiked concentration range 1-10 μg L -1 .

Solid-phase extraction and high-performance liquid chromatographic separation of pigments of red wines.

Science.gov (United States)

Csiktusnádi Kiss, G A; Forgács, E; Cserháti, T; Candeias, M; Vilas-Boas, L; Bronze, R; Spranger, I

2000-08-11

The adsorption and desorption capacities of 11 different solid-phase extraction sorbents were tested for the preconcenration of pigments of various Hungarian red wines. The concentrates were evaluated by multiwavelengh spectrophotometry combined with a spectral mapping technique (SPM) and by reversed-phase high-performance liquid chromatography. The highest (10-fold) concentration of pigments was achieved on octadecylsilica sorbent. It can be used five times without losing adsorption and desorption characteristics. SPM indicated that multiwavelength spectrophotometry can be employed for the differentiation of red wines. Comparison of the chromatograms of pigments with and without preconcentration showed that preconcentration makes possible the separation and detection of pigments present in low concentration in red wines.

Investigating the Retention Mechanisms of Liquid Chromatography Using Solid-Phase Extraction Cartridges

Science.gov (United States)

O'Donnell, Mary E.; Musial, Beata A.; Bretz, Stacey Lowery; Danielson, Neil D.; Ca, Diep

2009-01-01

Liquid chromatography (LC) experiments for the undergraduate analytical laboratory course often illustrate the application of reversed-phase LC to solve a separation problem, but rarely compare LC retention mechanisms. In addition, a high-performance liquid chromatography instrument may be beyond what some small colleges can purchase. Solid-phase…

Determination of quaternary ammonium compounds in seawater samples by solid-phase extraction and liquid chromatography-mass spectrometry.

Science.gov (United States)

Bassarab, P; Williams, D; Dean, J R; Ludkin, E; Perry, J J

2011-02-04

A method for the simultaneous determination of two biocidal quaternary ammonium compounds; didecyldimethylammonium chloride (didecyldimethyl quat) and dodecylbenzyldimethylammonium chloride (benzyl quat), in seawater by solid phase extraction (SPE) followed by liquid chromatography-mass spectrometry (LC-MS) was developed. The optimised procedure utilised off-line extraction of the analytes from seawater using polymeric (Strata-X) SPE cartridges. Recoveries ranged from 80 to 105%, with detection limits at the low parts-per-trillion (ng/l) level for both analytes. To demonstrate sensitivity, environmental concentrations were measured at three different locations along the North East coast of England with measured values in the range 120-270ng/l. Copyright © 2010 Elsevier B.V. All rights reserved.

Optimisation of pressurized liquid extraction using a multivariate chemometric approach for the determination of anticancer drugs in sludge by ultra high performance liquid chromatography-tandem mass spectrometry

OpenAIRE

Seira , Jordan; Claparols , Catherine; Joannis-Cassan , Claire; Albasi , Claire; Montréjaud-Vignoles , Mireille; Sablayrolles , Caroline

2013-01-01

International audience; The present paper describes an analytical method for the determination of 2 widely administered anticancer drugs, ifosfamide and cyclophosphamide, contained in sewage sludge. The method relies on the extraction from the solid matrix by pressurized liquid extraction, sample purification by solid-phase extraction and analysis by ultra high performance liquid chromatography coupled with tandem mass spectrometry. The different parameters affecting the extraction efficiency...

Solid-phase extraction of carotenoids.

Science.gov (United States)

Shen, Yao; Hu, Yumin; Huang, Ke; Yin, Shi'an; Chen, Bo; Yao, Shouzhuo

2009-07-24

In this work, solid-phase extraction (SPE) trapping performance of lutein and beta-carotene, which were used as the model molecules of carotenoids, was investigated. The absorption, elution, and enrichment of carotenoids on SPE cartridges with four different sorbents, i.e. C(30), C(18), diol, and silica, were compared respectively with the help of frontal analysis technique. The high retentions of both lutein and beta-carotene were achieved on the C(18) and C(30) cartridges. The diol and silica cartridges only had good retention for lutein. The optimized SPE method for sample pretreatment for the carotenoids analysis was obtained after the investigation of trapping performance. The method was applied successfully to the analysis of biological sample, i.e. serum and human breast milk. The recovery, accuracy, and precision of SPE method comparing with those of traditional liquid-liquid extraction (LLE) method for the sample pretreatment for the analysis of carotenoids owned a number of advantages such as rapid, no chloroform used, and accurate versus LLE.

Magnetically Enhanced Solid-Liquid Separation

Science.gov (United States)

Rey, C. M.; Keller, K.; Fuchs, B.

2005-07-01

DuPont is developing an entirely new method of solid-liquid filtration involving the use of magnetic fields and magnetic field gradients. The new hybrid process, entitled Magnetically Enhanced Solid-Liquid Separation (MESLS), is designed to improve the de-watering kinetics and reduce the residual moisture content of solid particulates mechanically separated from liquid slurries. Gravitation, pressure, temperature, centrifugation, and fluid dynamics have dictated traditional solid-liquid separation for the past 50 years. The introduction of an external field (i.e. the magnetic field) offers the promise to manipulate particle behavior in an entirely new manner, which leads to increased process efficiency. Traditional solid-liquid separation typically consists of two primary steps. The first is a mechanical step in which the solid particulate is separated from the liquid using e.g. gas pressure through a filter membrane, centrifugation, etc. The second step is a thermal drying process, which is required due to imperfect mechanical separation. The thermal drying process is over 100-200 times less energy efficient than the mechanical step. Since enormous volumes of materials are processed each year, more efficient mechanical solid-liquid separations can be leveraged into dramatic reductions in overall energy consumption by reducing downstream drying requirements have a tremendous impact on energy consumption. Using DuPont's MESLS process, initial test results showed four very important effects of the magnetic field on the solid-liquid filtration process: 1) reduction of the time to reach gas breakthrough, 2) less loss of solid into the filtrate, 3) reduction of the (solids) residual moisture content, and 4) acceleration of the de-watering kinetics. These test results and their potential impact on future commercial solid-liquid filtration is discussed. New applications can be found in mining, chemical and bioprocesses.

Preconcentration of uranium in water samples using dispersive liquid-liquid micro- extraction coupled with solid-phase extraction and determination with inductively coupled plasma-optical emission spectrometry

Directory of Open Access Journals (Sweden)

M. Rezaee,

2015-10-01

Full Text Available A new liquid phase microextraction method based on the dispersion of an extraction solvent into aqueous phase coupled with solid-phase extraction was investigated for the extraction, preconcentration and determination of uranium in water samples. 1-(2-Pyridylazo-2-naphthol reagent (PAN at pH 6.0 was used as a chelating agent prior to extraction. After concentration and purification of the samples in SPE C18 sorbent, 1.5 mL elution sample containing 40.0 µL chlorobenzene was injected into the 5.0 mL pure water. After extraction and centrifuging, the sedimented phase was evaporated and the residue was dissolved in nitric acid (0.5 M and was injected by injection valve into the ICP-OES. Some important extraction parameters, such as sample solution flow rate, sample pH, type and volume of extraction and disperser solvents as well as the salt addition were studied and optimized. Under the optimum conditions, the calibration graph was linear in the range of 0.5-500 µg L-1. The detection limit was 0.1 µg L-1. The relative standard deviation (RSD at 5.0 µg L-1 concentration level was 6.6%. Finally, the developed method was successfully applied to the extraction and determination of uranium in the well, river, mineral, waste and tap water samples and satisfactory results were obtained.DOI: http://dx.doi.org/10.4314/bcse.v29i3.4

Solid-phase micro-extraction in bioanalysis, exemplified by lidocaine determination

NARCIS (Netherlands)

de Jong, GJ; Koster, EHM

2000-01-01

Solid-phase micro-extraction (SPME) is a never sample preparation technique that can be used for gaseous, liquid or solid samples in conjunction with GC, HPLC or CE (e.g. [1]). The use of SPME for the analysis of drugs in biofluids is also becoming popular (e.g. [2]). The principle is that a fused

Liquid carry-over in an injection moulded all-polymer chip system for immiscible phase magnetic bead-based solid-phase extraction

Science.gov (United States)

Kistrup, Kasper; Skotte Sørensen, Karen; Wolff, Anders; Fougt Hansen, Mikkel

2015-04-01

We present an all-polymer, single-use microfluidic chip system produced by injection moulding and bonded by ultrasonic welding. Both techniques are compatible with low-cost industrial mass-production. The chip is produced for magnetic bead-based solid-phase extraction facilitated by immiscible phase filtration and features passive liquid filling and magnetic bead manipulation using an external magnet. In this work, we determine the system compatibility with various surfactants. Moreover, we quantify the volume of liquid co-transported with magnetic bead clusters from Milli-Q water or a lysis-binding buffer for nucleic acid extraction (0.1 (v/v)% Triton X-100 in 5 M guanidine hydrochloride). A linear relationship was found between the liquid carry-over and mass of magnetic beads used. Interestingly, similar average carry-overs of 1.74(8) nL/μg and 1.72(14) nL/μg were found for Milli-Q water and lysis-binding buffer, respectively.

Determination of phenolic derivatives of antipyrine in plasma with solid-phase extraction and high-performance liquid chromatography-atmospheric-pressure chemical ionization mass spectrometry

NARCIS (Netherlands)

Coolen, S.A.J.; Ligor, T.; Lieshout, van H.P.M.; Huf, F.A.

1999-01-01

This manuscript describes a method to determine antipyrine and its phenolic derivatives in plasma by reversed-phase high-performance liquid chromatography–mass spectrometry (RP-HPLC–MS). The sample pretreatment consisted of a C18 solid-phase extraction (SPE), to remove the salts and proteins. The

Combination of solid phase extraction and dispersive liquid-liquid microextraction for separation/preconcentration of ultra trace amounts of uranium prior to its fiber optic-linear array spectrophotometry determination.

Science.gov (United States)

Dadfarnia, Shayessteh; Shabani, Ali Mohammad Haji; Shakerian, Farid; Shiralian Esfahani, Golnaz

2013-12-15

A simple and sensitive method for the separation and preconcentration of the ultra trace amounts of uranium and its determination by spectrophotometry was developed. The method is based on the combination of solid phase extraction and dispersive liquid-liquid microextraction. Thus, by passing the sample through the basic alumina column, the uranyl ion and some cations are separated from the sample matrix. The retained uranyl ion along with the cations are eluted with 5 mL of nitric acid (2 mol L(-1)) and after neutralization of the eluent, the extracted uranyl ion is converted to its anionic benzoate complex and is separated from other cations by extraction of its ion pair with malachite green into small volume of chloroform using dispersive liquid-liquid microextraction. The amount of uranium is then determined by the absorption measurement of the extracted ion pair at 621 nm using flow injection spectrophotometry. Under the optimum conditions, with 500 mL of the sample, a preconcentration factor of 1980, a detection limit of 40 ng L(-1), and a relative standard deviation of 4.1% (n=6) at 400 ng L(-1) were obtained. The method was successfully applied to the determination of uranium in mineral water, river water, well water, spring water and sea water samples. Copyright © 2013 Elsevier B.V. All rights reserved.

Determination of rifampicin in human plasma by high-performance liquid chromatography coupled with ultraviolet detection after automatized solid-liquid extraction.

Science.gov (United States)

Louveau, B; Fernandez, C; Zahr, N; Sauvageon-Martre, H; Maslanka, P; Faure, P; Mourah, S; Goldwirt, L

2016-12-01

A precise and accurate high-performance liquid chromatography (HPLC) quantification method of rifampicin in human plasma was developed and validated using ultraviolet detection after an automatized solid-phase extraction. The method was validated with respect to selectivity, extraction recovery, linearity, intra- and inter-day precision, accuracy, lower limit of quantification and stability. Chromatographic separation was performed on a Chromolith RP 8 column using a mixture of 0.05 m acetate buffer pH 5.7-acetonitrile (35:65, v/v) as mobile phase. The compounds were detected at a wavelength of 335 nm with a lower limit of quantification of 0.05 mg/L in human plasma. Retention times for rifampicin and 6,7-dimethyl-2,3-di(2-pyridyl) quinoxaline used as internal standard were respectively 3.77 and 4.81 min. This robust and exact method was successfully applied in routine for therapeutic drug monitoring in patients treated with rifampicin. Copyright © 2016 John Wiley & Sons, Ltd.

METHOD 544. DETERMINATION OF MICROCYSTINS AND NODULARIN IN DRINKING WATER BY SOLID PHASE EXTRACTION AND LIQUID CHROMATOGRAPHY/TANDEM MASS SPECTROMETRY (LC/MS/MS)

Science.gov (United States)

Method 544 is an accurate and precise analytical method to determine six microcystins (including MC-LR) and nodularin in drinking water using solid phase extraction and liquid chromatography tandem mass spectrometry (SPE-LC/MS/MS). The advantage of this SPE-LC/MS/MS is its sensi...

Preconcentration and Determination of Perfluoroalkyl Substances (PFASs in Water Samples by Bamboo Charcoal-Based Solid-Phase Extraction Prior to Liquid Chromatography–Tandem Mass Spectrometry

Directory of Open Access Journals (Sweden)

Ze-Hui Deng

2018-04-01

Full Text Available In this work, bamboo charcoal was used as solid-phase extraction adsorbent for the enrichment of six perfluoroalkyl acids (PFAAs in environmental water samples before liquid chromatography–tandem mass spectrometry analysis. The specific porous structure, high specific surface area, high porosity, and stability of bamboo charcoal were characterized. Several experimental parameters which considerably affect extraction efficiency were investigated and optimized in detail. The experimental data exhibited low limits of detection (LODs (0.01–1.15 ng/L, wide linear range (2–3 orders of magnitude and R ≥ 0.993 within the concentration range of 0.1–1000 ng/L, and good repeatability (2.7–5.0%, n = 5 intraday and 4.8–8.3%, n = 5 interday and reproducibility (5.3–8.0%, n = 3. Bamboo charcoal was successfully used for the enrichment and determination of PFAAs in real environmental water samples. The bamboo charcoal-based solid-phase extraction coupled with liquid chromatography–tandem mass spectrometry analysis possessed great potential in the determination of trace PFAA levels in environmental water samples.

Simultaneous analysis of carotenoids and tocopherols in botanical species using one step solid-liquid extraction followed by high performance liquid chromatography.

Science.gov (United States)

Valdivielso, Izaskun; Bustamante, María Ángeles; Ruiz de Gordoa, Juan Carlos; Nájera, Ana Isabel; de Renobales, Mertxe; Barron, Luis Javier R

2015-04-15

Carotenoids and tocopherols from botanical species abundant in Atlantic mountain grasslands were simultaneously extracted using one-step solid-liquid phase. A single n-hexane/2-propanol extract containing both types of compounds was injected twice under two different sets of HPLC conditions to separate the tocopherols by normal-phase chromatography and carotenoids by reverse-phase mode. The method allowed reproducible quantification in plant samples of very low amounts of α-, β-, γ- and δ-tocopherols (LOD from 0.0379 to 0.0720 μg g(-1) DM) and over 15 different xanthophylls and carotene isomers. The simplified one-step extraction without saponification significantly increased the recovery of tocopherols and carotenoids, thereby enabling the determination of α-tocopherol acetate in plant samples. The two different sets of chromatographic analysis provided near baseline separation of individual compounds without interference from other lipid compounds extracted from plants, and a very sensitive and accurate detection of tocopherols and carotenoids. The detection of minor individual components in botanical species from grasslands is nowadays of high interest in searching for biomarkers for foods derived from grazing animals. Copyright © 2014 Elsevier Ltd. All rights reserved.

Determination of twelve herbicides in tobacco by a combination of solid–liquid–solid dispersive extraction using multi-walled carbon nanotubes, dispersive liquid-liquid micro-extraction, and detection by GC with triple quadrupole mass spectrometry

International Nuclear Information System (INIS)

Liao, Qie Gen; Zhou, Yao Min; Luo, Lin Guang; Wang, Li Bing; Feng, Xiao Hu

2014-01-01

We report on a method for the determination of twelve herbicides using solid–liquid–solid dispersive extraction (SLSDE), followed by dispersive liquid-liquid micro-extraction (DLLME) and quantitation by gas chromatography with triple quadrupole mass spectrometric detection. SLSDE was applied to the extraction of herbicides from tobacco samples using multi-walled carbon nanotubes (MWCNTs) as clean-up adsorbents. The effect of the quantity of MWCNTs on SLSDE, and of type and volume of extraction and disperser solvents and of salt effect on DLLME were optimized. Good linearity is obtained in the 5.0 - 500 μg kg −1 concentration range, with regression coefficients of >0.99. Intra-day and inter-day repeatability, expressed as relative standard deviations, are between 3 and 9 %. The recoveries in case of herbicide-spiked tobacco at concentration levels of 20.0, 50.0 and 100.0 g kg −1 ranged from 79 to 105 %, and LODs are between 1.5 and 6.1 μg kg −1 . All the tobacco samples were found to contain butralin and pendimethalin at levels ranging from 15.8 to 500.0 μg kg −1 . (author)

A novel polymeric ionic liquid-coated magnetic multiwalled carbon nanotubes for the solid-phase extraction of Cu, Zn-superoxide dismutase

Energy Technology Data Exchange (ETDEWEB)

Wen, Qian; Wang, Yuzhi, E-mail: wyzss@hnu.edu.cn; Xu, Kaijia; Li, Na; Zhang, Hongmei; Yang, Qin

2016-10-05

A novel magnetic adsorbent, benzyl groups functionalized imidazolium-based polymeric ionic liquid (PIL)-coated magnetic multiwalled carbon nanotubes (MWCNTs) (m-MWCNTs@PIL), has been successfully synthesized and applied for the extraction of Cu, Zn-superoxide dismutase (Cu, Zn-SOD). The m-MWCNTs@PIL were characterized by X-ray diffraction (XRD), Fourier transform infrared spectrometry (FT-IR), thermal gravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), vibrating sample magnetometer (VSM) and zeta-potential nanoparticles. In this method, the m-MWCNTs@PIL could interact with Cu, Zn-SOD through hydrogen bonding, π-π and electrostatic interactions. The extraction performance of the m-MWCNTs@PIL in the magnetic solid-phase extraction (MSPE) procedure was investigated, coupled with the determination by UV–vis spectrophotometer. Compared with m-MWCNTs@IL and m-MWCNTs, the m-MWCNTs@PIL exhibited the highest extraction capacity of 29.1 mg/g for Cu, Zn-SOD. The adsorbed Cu, Zn-SOD remained high specific activity after being eluted from m-MWCNTs@PIL by 1 moL/L NaCl solution. Besides, the m-MWCNTs@PIL could be easily recycled and successfully employed in the extraction of Cu, Zn-SOD from real samples. Under the optimal conditions, the precision, repeatability and stability of the proposed method were investigated and the RSDs were 0.29%, 1.68% and 0.54%, respectively. Recoveries were in the range of 82.7–102.3%, with the RSD between 3.47% and 5.35%. On the basis of these results, the developed method has great potential in the extraction of Cu, Zn-SOD or other analytes from biological samples. - Highlights: • A strategy for the magnetic solid-phase extraction of Cu, Zn-SOD based on polymeric ionic liquid has been developed. • The Cu, Zn-SOD remained high specific activity after extraction. • The magnetic adsorbent could be recycled and successfully employed in the extraction of Cu, Zn-SOD from real samples.

A novel polymeric ionic liquid-coated magnetic multiwalled carbon nanotubes for the solid-phase extraction of Cu, Zn-superoxide dismutase

International Nuclear Information System (INIS)

Wen, Qian; Wang, Yuzhi; Xu, Kaijia; Li, Na; Zhang, Hongmei; Yang, Qin

2016-01-01

A novel magnetic adsorbent, benzyl groups functionalized imidazolium-based polymeric ionic liquid (PIL)-coated magnetic multiwalled carbon nanotubes (MWCNTs) (m-MWCNTs@PIL), has been successfully synthesized and applied for the extraction of Cu, Zn-superoxide dismutase (Cu, Zn-SOD). The m-MWCNTs@PIL were characterized by X-ray diffraction (XRD), Fourier transform infrared spectrometry (FT-IR), thermal gravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), vibrating sample magnetometer (VSM) and zeta-potential nanoparticles. In this method, the m-MWCNTs@PIL could interact with Cu, Zn-SOD through hydrogen bonding, π-π and electrostatic interactions. The extraction performance of the m-MWCNTs@PIL in the magnetic solid-phase extraction (MSPE) procedure was investigated, coupled with the determination by UV–vis spectrophotometer. Compared with m-MWCNTs@IL and m-MWCNTs, the m-MWCNTs@PIL exhibited the highest extraction capacity of 29.1 mg/g for Cu, Zn-SOD. The adsorbed Cu, Zn-SOD remained high specific activity after being eluted from m-MWCNTs@PIL by 1 moL/L NaCl solution. Besides, the m-MWCNTs@PIL could be easily recycled and successfully employed in the extraction of Cu, Zn-SOD from real samples. Under the optimal conditions, the precision, repeatability and stability of the proposed method were investigated and the RSDs were 0.29%, 1.68% and 0.54%, respectively. Recoveries were in the range of 82.7–102.3%, with the RSD between 3.47% and 5.35%. On the basis of these results, the developed method has great potential in the extraction of Cu, Zn-SOD or other analytes from biological samples. - Highlights: • A strategy for the magnetic solid-phase extraction of Cu, Zn-SOD based on polymeric ionic liquid has been developed. • The Cu, Zn-SOD remained high specific activity after extraction. • The magnetic adsorbent could be recycled and successfully employed in the extraction of Cu, Zn-SOD from real samples.

Use of micro-emulsions in liquid-liquid extraction

International Nuclear Information System (INIS)

Komornicki, Jacques

1982-01-01

As liquid-liquid extraction of metallic cations is an important method of separation and concentration of metals present in diluted aqueous solutions, and as the extraction rate is limited by one or several steps of matter transfer at the liquid-liquid interface, the extraction kinetics can be improved by creating a wide surface interface and by allowing an increased reactivity between species. In this research thesis, the author aims at determining to which extent systems of interface with a wide surface obtained by using for example amphiphile molecules to create micro-emulsions, can be used as reaction media for physical-chemical processes of liquid-liquid extraction. He also aims at identifying their applicability limitations and problems which might arise with their application. The author notably focuses of the liquid-liquid extraction of metallic cations exhibiting particularly slow extraction kinetics

Hypercrosslinked particles for the extraction of sweeteners using dispersive solid-phase extraction from environmental samples.

Science.gov (United States)

Lakade, Sameer S; Zhou, Qing; Li, Aimin; Borrull, Francesc; Fontanals, Núria; Marcé, Rosa M

2018-04-01

This work presents a new extraction material, namely, Q-100, based on hypercrosslinked magnetic particles, which was tested in dispersive solid-phase extraction for a group of sweeteners from environmental samples. The hypercrosslinked Q-100 magnetic particles had the advantage of suitable pore size distribution and high surface area, and showed good retention behavior toward sweeteners. Different dispersive solid-phase extraction parameters such as amount of magnetic particles or extraction time were optimized. Under optimum conditions, Q-100 showed suitable apparent recovery, ranging in the case of river water sample from 21 to 88% for all the sweeteners, except for alitame (12%). The validated method based on dispersive solid-phase extraction using Q-100 followed by liquid chromatography with tandem mass spectrometry provided good linearity and limits of quantification between 0.01 and 0.1 μg/L. The method was applied to analyze samples from river water and effluent wastewater, and four sweeteners (acesulfame, saccharin, cyclamate, and sucralose) were found in both types of sample. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

New method based on combining ultrasonic assisted miniaturized matrix solid-phase dispersion and homogeneous liquid-liquid extraction for the determination of some organochlorinated pesticides in fish

International Nuclear Information System (INIS)

Rezaei, Farahnaz; Hosseini, Mohammad-Reza Milani

2011-01-01

Highlights: → Ultrasonic assisted miniaturized matrix solid-phase dispersion combined with HLLE was developed as a new method for the extraction of OCPs in fish. → The goal of this combination was to enhance the selectivity of HLLE procedure and to extend its application in biological samples. → This method proposed the advantages of good detection limits, lower consumption of reagents, and does not need any special instrumentation. - Abstract: In this study, ultrasonic assisted miniaturized matrix solid-phase dispersion (US-MMSPD) combined with homogeneous liquid-liquid extraction (HLLE) has been developed as a new method for the extraction of organochlorinated pesticides (OCPs) in fish prior to gas chromatography with electron capture detector (GC-ECD). In the proposed method, OCPs (heptachlor, aldrin, DDE, DDD, lindane and endrin) were first extracted from fish sample into acetonitrile by US-MMSPD procedure, and the extract was then used as consolute solvent in HLLE process. Optimal condition for US-MMSPD step was as follows: volume of acetonitrile, 1.5 mL; temperature of ultrasound, 40 deg. C; time of ultrasound, 10 min. For HLLE step, optimal results were obtained at the following conditions: volume of chloroform, 35 μL; volume of aqueous phase, 1.5 mL; volume of double distilled water, 0.5 mL; time of centrifuge, 10 min. Under the optimum conditions, the enrichment factors for the studied compounds were obtained in the range of 185-240, and the overall recoveries were ranged from 39.1% to 81.5%. The limits of detection were 0.4-1.2 ng g -1 and the relative standard deviations for 20 ng g -1 of the OCPs, varied from 3.2% to 8% (n = 4). Finally, the proposed method has been successfully applied to the analysis of the OCPs in real fish sample, and satisfactory results were obtained.

New method based on combining ultrasonic assisted miniaturized matrix solid-phase dispersion and homogeneous liquid-liquid extraction for the determination of some organochlorinated pesticides in fish

Energy Technology Data Exchange (ETDEWEB)

Rezaei, Farahnaz [Department of Analytical Chemistry, Faculty of Chemistry, Iran University of Science and Technology, Narmak, Tehran 16846 (Iran, Islamic Republic of); Hosseini, Mohammad-Reza Milani, E-mail: drmilani@iust.ac.ir [Department of Analytical Chemistry, Faculty of Chemistry, Iran University of Science and Technology, Narmak, Tehran 16846 (Iran, Islamic Republic of); Electroanalytical Chemistry Research Center, Iran University of Science and Technology, Narmak, Tehran 16846 (Iran, Islamic Republic of)

2011-09-30

Highlights: {yields} Ultrasonic assisted miniaturized matrix solid-phase dispersion combined with HLLE was developed as a new method for the extraction of OCPs in fish. {yields} The goal of this combination was to enhance the selectivity of HLLE procedure and to extend its application in biological samples. {yields} This method proposed the advantages of good detection limits, lower consumption of reagents, and does not need any special instrumentation. - Abstract: In this study, ultrasonic assisted miniaturized matrix solid-phase dispersion (US-MMSPD) combined with homogeneous liquid-liquid extraction (HLLE) has been developed as a new method for the extraction of organochlorinated pesticides (OCPs) in fish prior to gas chromatography with electron capture detector (GC-ECD). In the proposed method, OCPs (heptachlor, aldrin, DDE, DDD, lindane and endrin) were first extracted from fish sample into acetonitrile by US-MMSPD procedure, and the extract was then used as consolute solvent in HLLE process. Optimal condition for US-MMSPD step was as follows: volume of acetonitrile, 1.5 mL; temperature of ultrasound, 40 deg. C; time of ultrasound, 10 min. For HLLE step, optimal results were obtained at the following conditions: volume of chloroform, 35 {mu}L; volume of aqueous phase, 1.5 mL; volume of double distilled water, 0.5 mL; time of centrifuge, 10 min. Under the optimum conditions, the enrichment factors for the studied compounds were obtained in the range of 185-240, and the overall recoveries were ranged from 39.1% to 81.5%. The limits of detection were 0.4-1.2 ng g{sup -1} and the relative standard deviations for 20 ng g{sup -1} of the OCPs, varied from 3.2% to 8% (n = 4). Finally, the proposed method has been successfully applied to the analysis of the OCPs in real fish sample, and satisfactory results were obtained.

Parallel artificial liquid membrane extraction

DEFF Research Database (Denmark)

Gjelstad, Astrid; Rasmussen, Knut Einar; Parmer, Marthe Petrine

2013-01-01

This paper reports development of a new approach towards analytical liquid-liquid-liquid membrane extraction termed parallel artificial liquid membrane extraction. A donor plate and acceptor plate create a sandwich, in which each sample (human plasma) and acceptor solution is separated by an arti......This paper reports development of a new approach towards analytical liquid-liquid-liquid membrane extraction termed parallel artificial liquid membrane extraction. A donor plate and acceptor plate create a sandwich, in which each sample (human plasma) and acceptor solution is separated...... by an artificial liquid membrane. Parallel artificial liquid membrane extraction is a modification of hollow-fiber liquid-phase microextraction, where the hollow fibers are replaced by flat membranes in a 96-well plate format....

Separation of uranium from aqueous solutions using calix[6]arenes in liquid-liquid extraction as well as solid phase extraction

International Nuclear Information System (INIS)

Schmeide, K.; Geipel, G.; Bernhard, G.

2004-11-01

The suitability of different calyx[n] arene types for uranyl extraction from liquid solutions was examined by means of liquid-liquid extraction using aqueous phases and organic solvents of varying compositions. It was found that COOH-derivatised calyx[6] arenes have good extraction properties and can even be used in the acid pH range. The use of calixarene-modified fleeces for the separation of uranyl from aqueous phases was examined in batch experiments with pH and uranyl concentration as variables and in the presence or absence of competing ions. The results showed that calixarene-modified fleeces can be used for uranium separation starting from pH 4. At pH 5, up to a maximum of 7.6 x 10 -7 mol uranium can be bound per 1 g of calixarene-modified fleece. The separation of uranyl from synthetic pit waters was examined as a means of testing the separation capacity of calixarene-modified fleeces in environmentally sensitive waters. Studies on the reversibility of uranium bonding to calixarene-treated polyester fleeces have shown that under environmentally realistic conditions (neutral pH range) the uranium is firmly bound to the calixarene-modified fleeces and cannot be mobilised. By contrast, in acidic environments calixarene-modified fleeces are capable of near-complete regeneration. Such regenerated textile filter materials can then be used for further uranium separation cycles [de

Solid-phase extraction versus matrix solid-phase dispersion: Application to white grapes.

Science.gov (United States)

Dopico-García, M S; Valentão, P; Jagodziñska, A; Klepczyñska, J; Guerra, L; Andrade, P B; Seabra, R M

2007-11-15

The use of matrix solid-phase dispersion (MSPD) was tested to, separately, extract phenolic compounds and organic acids from white grapes. This method was compared with a more conventional analytical method previously developed that combines solid liquid extraction (SL) to simultaneously extract phenolic compounds and organic acids followed by a solid-phase extraction (SPE) to separate the two types of compounds. Although the results were qualitatively similar for both techniques, the levels of extracted compounds were in general quite lower on using MSPD, especially for organic acids. Therefore, SL-SPE method was preferred to analyse white "Vinho Verde" grapes. Twenty samples of 10 different varieties (Alvarinho, Avesso, Asal-Branco, Batoca, Douradinha, Esganoso de Castelo Paiva, Loureiro, Pedernã, Rabigato and Trajadura) from four different locations in Minho (Portugal) were analysed in order to study the effects of variety and origin on the profile of the above mentioned compounds. Principal component analysis (PCA) was applied separately to establish the main sources of variability present in the data sets for phenolic compounds, organic acids and for the global data. PCA of phenolic compounds accounted for the highest variability (77.9%) with two PCs, enabling characterization of the varieties of samples according to their higher content in flavonol derivatives or epicatechin. Additionally, a strong effect of sample origin was observed. Stepwise linear discriminant analysis (SLDA) was used for differentiation of grapes according to the origin and variety, resulting in a correct classification of 100 and 70%, respectively.

Separation and Purification of Sulforaphane from Broccoli by Solid Phase Extraction

Directory of Open Access Journals (Sweden)

Kyung Ho Row

2011-03-01

Full Text Available A simple solid-phase extraction (SPE method for the determination of sulforaphane in broccoli has been developed. The optimal conditions were found to be use of a silica SPE cartridge, and ethyl acetate and dichloromethane as washing and eluting solvents, respectively, which could eliminate interferences originating from the broccoli matrix. The extracts were sufficiently clean to be directly injected into high-performance liquid chromatography (HPLC for further chromatographic analysis. Good linearity was obtained from 0.05 to 200 μg/mL (r = 0.998 for sulforaphane with the relative standard deviations less than 3.6%. The mean recoveries of sulforaphane from broccoli were more than 90.8% and the detection limit (S/N = 3:1 was 0.02 μg/mL. The SPE method provides a higher yield of sulforaphane from crude extracts compared to conventional liquid-liquid extraction.

Liquid carry-over in an injection moulded all-polymer chip system for immiscible phase magnetic bead-based solid-phase extraction

DEFF Research Database (Denmark)

Kistrup, Kasper; Sørensen, Karen Skotte; Wolff, Anders

2014-01-01

We present an all-polymer, single-use microfluidic chip system produced by injection moulding and bonded by ultrasonic welding. Both techniques are compatible with low-cost industrial mass-production. The chip is produced for magnetic bead-based solid-phase extraction facilitated by immiscible......-binding buffer for nucleic acid extraction (0.1 (v/v)% Triton X-100 in 5 M guanidine hydrochloride). A linear relationship was found between the liquid carry-over and mass of magnetic beads used. Interestingly, similar average carry-overs of 1.74(8) nL/µg and 1.72(14) nL/µg were found for Milli-Q water and lysis...

Pressurized liquid extraction using water/isopropanol coupled with solid-phase extraction cleanup for industrial and anthropogenic waste-indicator compounds in sediment

Science.gov (United States)

Burkhardt, M.R.; ReVello, R.C.; Smith, S.G.; Zaugg, S.D.

2005-01-01

A broad range of organic compounds is recognized as environmentally relevant for their potential adverse effects on human and ecosystem health. This method was developed to better determine the distribution of 61 compounds that are typically associated with industrial and household waste as well as some that are toxic and known (or suspected) for endocrine-disrupting potential extracted from environmental sediment samples. Pressurized liquid extraction (PLE) coupled with solid-phase extraction (SPE) was used to reduce sample preparation time, reduce solvent consumption to one-fifth of that required using dichloromethane-based Soxhlet extraction, and to minimize background interferences for full scan GC/MS analysis. Recoveries from spiked Ottawa sand, commercially available topsoil, and environmental stream sediment, fortified at 4-720 ??g per compound, averaged 76 ?? 13%. Initial method detection limits for single-component compounds ranged from 12.5 to 520 ??g/kg, based on 25 g samples. Results from 103 environmental sediment samples show that 36 out of 61 compounds (59%) were detected in at least one sample with concentrations ranging from 20 to 100,000 ??g/kg. The most frequently detected compound, beta-sitosterol, a plant sterol, was detected in 87 of the 103 (84.5%) environmental samples with a concentration range 360-100,000 ??g/kg. Results for a standard reference material using dichloromethane Soxhlet-based extraction are also compared. ?? 2004 Published by Elsevier B.V.

The use of solid sorbents for direct accumulation of organic compounds from water matrices : a review of solid-phase extraction techniques

NARCIS (Netherlands)

Liska, I.; Krupcik, J.; Leclercq, P.A.

1989-01-01

The main principles of solid-phase extraction techniques are reviewed in this paper. Various solid sorbents can be used as a suitable trap for direct accumulation of organic compounds from aqueous solutions. The trapped analytes can be desorbed by elution with suitably chosen liquid phases. These

Liquid carry-over in an injection moulded all-polymer chip system for immiscible phase magnetic bead-based solid-phase extraction

Energy Technology Data Exchange (ETDEWEB)

Kistrup, Kasper, E-mail: kkis@nanotech.dtu.dk [Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech, Building 345 East, DK-2800 Kongens Lyngby (Denmark); Skotte Sørensen, Karen, E-mail: karen@nanotech.dtu.dk [Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech, Building 345 East, DK-2800 Kongens Lyngby (Denmark); Center for Integrated Point of Care Technologies (CiPoC), DELTA, Venlighedsvej 4, DK-2870 Hørsholm (Denmark); Wolff, Anders, E-mail: anders.wolff@nanotech.dtu.dk [Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech, Building 345 East, DK-2800 Kongens Lyngby (Denmark); Fougt Hansen, Mikkel, E-mail: mikkel.hansen@nanotech.dtu.dk [Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech, Building 345 East, DK-2800 Kongens Lyngby (Denmark)

2015-04-15

We present an all-polymer, single-use microfluidic chip system produced by injection moulding and bonded by ultrasonic welding. Both techniques are compatible with low-cost industrial mass-production. The chip is produced for magnetic bead-based solid-phase extraction facilitated by immiscible phase filtration and features passive liquid filling and magnetic bead manipulation using an external magnet. In this work, we determine the system compatibility with various surfactants. Moreover, we quantify the volume of liquid co-transported with magnetic bead clusters from Milli-Q water or a lysis-binding buffer for nucleic acid extraction (0.1 (v/v)% Triton X-100 in 5 M guanidine hydrochloride). A linear relationship was found between the liquid carry-over and mass of magnetic beads used. Interestingly, similar average carry-overs of 1.74(8) nL/µg and 1.72(14) nL/µg were found for Milli-Q water and lysis-binding buffer, respectively. - Highlights: • We present an all-polymer mass producible passive filled microfluidic chip system. • Rapid system fabrication is obtained by injection moulding and ultrasonic welding. • The system is made for single-use nucleic acid extraction using magnetic beads. • We systematically map compatibility of the chip system with various surfactants. • We quantify the volume carry-over of magnetic beads in water and 0.1% triton-X solution.

Liquid carry-over in an injection moulded all-polymer chip system for immiscible phase magnetic bead-based solid-phase extraction

International Nuclear Information System (INIS)

Kistrup, Kasper; Skotte Sørensen, Karen; Wolff, Anders; Fougt Hansen, Mikkel

2015-01-01

We present an all-polymer, single-use microfluidic chip system produced by injection moulding and bonded by ultrasonic welding. Both techniques are compatible with low-cost industrial mass-production. The chip is produced for magnetic bead-based solid-phase extraction facilitated by immiscible phase filtration and features passive liquid filling and magnetic bead manipulation using an external magnet. In this work, we determine the system compatibility with various surfactants. Moreover, we quantify the volume of liquid co-transported with magnetic bead clusters from Milli-Q water or a lysis-binding buffer for nucleic acid extraction (0.1 (v/v)% Triton X-100 in 5 M guanidine hydrochloride). A linear relationship was found between the liquid carry-over and mass of magnetic beads used. Interestingly, similar average carry-overs of 1.74(8) nL/µg and 1.72(14) nL/µg were found for Milli-Q water and lysis-binding buffer, respectively. - Highlights: • We present an all-polymer mass producible passive filled microfluidic chip system. • Rapid system fabrication is obtained by injection moulding and ultrasonic welding. • The system is made for single-use nucleic acid extraction using magnetic beads. • We systematically map compatibility of the chip system with various surfactants. • We quantify the volume carry-over of magnetic beads in water and 0.1% triton-X solution

Determination of ciprofloxacin in Jiaozhou Bay using molecularly imprinted solid-phase extraction followed by high-performance liquid chromatography with fluorescence detection

International Nuclear Information System (INIS)

Lian, Ziru; Wang, Jiangtao

2016-01-01

A high selective pre-treatment method for the cleanup and preconcentration of ciprofloxacin in natural seawater samples was developed based on molecularly imprinted solid-phase extraction (MISPE). The ciprofloxacin imprinted polymers were synthesized and the characteristics of obtained polymers were evaluated by scanning electron microscopy, Fourier transform infrared spectroscopy and binding experiments. The imprinted materials showed high adsorption ability for ciprofloxacin and were applied as special solid-phase extraction sorbents for selective separation of ciprofloxacin. An off-line MISPE procedure was optimized and the developed MISPE method allowed direct purification and enrichment of the ciprofloxacin from the aqueous samples prior to high-performance liquid chromatography analysis. The recoveries of spiked seawater on the MISPE cartridges ranged from 75.2 to 112.4% and the relative standard deviations were less than 4.46%. Five seawater samples from Jiaozhou Bay were analyzed and ciprofloxacin was detected in two samples with the concentrations of 0.24 and 0.38 μg L −1 , respectively. - Highlights: • Ciprofloxacin molecularly imprinted polymers (Cip-MIPs) were prepared. • The characteristics and recognition efficiency of MIPs were studied. • An off-line method for Cip was developed using MIPs as solid-phase extraction. • Cip in five seawater samples from Jiaozhou Bay of China was determined.

ON-SITE SOLID PHRASE EXTRACTION AND LABORATORY ...

Science.gov (United States)

Fragrance materials, such as synthetic musks in aqueous samples, are normally analyzed by GC/MS in the selected ion monitoring (SIM) mode to provide maximum sensitivity after liquid-liquid extraction of I -L samples. A I -L sample, however, usually provides too little analyte for full-scan data acquisition. An on-site extraction method for extracting synthetic musks from 60 L of wastewater effluent has been developed. Such a large sample volume permits high-quality, full-scan mass spectra to be obtained for various synthetic musk compounds. Quantification of these compounds was conveniently achieved from the full-scan data directly, without preparing SIM descriptors for each compound to acquire SIM data. The research focused on in the subtasks is the development and application of state-of the-art technologies to meet the needs of the public, Office of Water, and ORD in the area of Water Quality. Located In the subtasks are the various research projects being performed in support of this Task and more in-depth coverage of each project. Briefly, each project's objective is stated below.Subtask 1: To integrate state-of-the-art technologies (polar organic chemical integrative samplers, advanced solid-phase extraction methodologies with liquid chromatography/electrospray/mass spectrometry) and apply them to studying the sources and fate of a select list of PPCPs. Application and improvement of analytical methodologies that can detect non-volatile, polar, water-sol

The competition between the liquid-liquid dewetting and the liquid-solid dewetting.

Science.gov (United States)

Xu, Lin; Shi, Tongfei; An, Lijia

2009-05-14

We investigate the dewetting behavior of the bilayer of air/PS/PMMA/silanized Si wafer and find the two competing dewetting pathways in the dewetting process. The upper layer dewets on the lower layer (dewetting pathway 1, the liquid-liquid dewetting) and the two layers rupture on the solid substrate (dewetting pathway 2, the liquid-solid dewetting). To the two competing dewetting pathways, the process of forming holes and the process of hole growth, influence their competing relation. In the process of forming holes, the time of forming holes is a main factor that influences their competing relation. During the process of hole growth, the dewetting velocity is a main factor that influences their competing relation. The liquid-liquid interfacial tension, the film thickness of the polymer, and the viscosity of the polymer are important factors that influence the time of forming holes and the dewetting velocity. When the liquid-liquid dewetting pathway and the liquid-solid dewetting pathway compete in the dewetting process, the competing relation can be controlled by changing the molecular weight of the polymer, the film thickness, and the annealing temperature. In addition, it is also found that the rim growth on the solid substrate is by a rolling mechanism in the process of hole growth.

A new carbon-based magnetic material for the dispersive solid-phase extraction of UV filters from water samples before liquid chromatography-tandem mass spectrometry analysis.

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Piovesana, Susy; Capriotti, Anna Laura; Cavaliere, Chiara; La Barbera, Giorgia; Samperi, Roberto; Zenezini Chiozzi, Riccardo; Laganà, Aldo

2017-07-01

Magnetic solid-phase extraction is one of the most promising new extraction methods for liquid samples before ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis. Several types of materials, including carbonaceous ones, have been prepared for this purpose. In this paper, for the first time, the preparation, characterization, and sorption capability of Fe 3 O 4 -graphitized carbon black (mGCB) composite toward some compounds of environmental interest were investigated. The synthesized mGCB consisted of micrometric GCB particles with 55 m 2  g -1 surface area bearing some carbonyl and hydroxyl functionalities and the surface partially decorated by Fe 3 O 4 microparticles. The prepared mGCB was firstly tested as an adsorbent for the extraction from surface water of 50 pollutants, including estrogens, perfluoroalkyl compounds, UV filters, and quinolones. The material showed good affinity to many of the tested compounds, except carboxylates and glucoronates; however, some compounds were difficult to desorb. Ten UV filters belonging to the chemical classes of benzophenones and p-aminobenzoates were selected, and parameters were optimized for the extraction of these compounds from surface water before UHPLC-MS/MS determination. Then, the method was validated in terms of linearity, trueness, intra-laboratory precision, and detection and quantification limits. In summary, the method performance (trueness, expressed as analytical recovery, 85-114%; RSD 5-15%) appears suitable for the determination of the selected compounds at the level of 10-100 ng L -1 , with detection limits in the range of 1-5 ng L -1 . Finally, the new method was compared with a published one, based on conventional solid-phase extraction with GCB, showing similar performance in real sample analysis. Graphical Abstract Workflow of the analytical method based on magnetic solid-phase extraction followed by LC-MS/MS determination.

Determination of haloacetic acids in water using layered double hydroxides as a sorbent in dispersive solid-phase extraction followed by liquid chromatography with tandem mass spectrometry.

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Alsharaa, Abdulnaser; Sajid, Muhammad; Basheer, Chanbasha; Alhooshani, Khalid; Lee, Hian Kee

2016-09-01

In the present study, highly efficient and simple dispersive solid-phase extraction procedure for the determination of haloacetic acids in water samples has been established. Three different types of layered double hydroxides were synthesized and used as a sorbent in dispersive solid-phase extraction. Due to the interesting behavior of layered double hydroxides in an acidic medium (pH˂4), the analyte elution step was not needed; the layered double hydroxides are simply dissolved in acid immediately after extraction to release the analytes which are then directly introduced into a liquid chromatography with tandem mass spectrometry system for analysis. Several dispersive solid-phase extraction parameters were optimized to increase the extraction efficiency of haloacetic acids such as temperature, extraction time and pH. Under optimum conditions, good linearity was achieved over the concentration range of 0.05-100 μg/L with detection limits in the range of 0.006-0.05 μg/L. The relative standard deviations were 0.33-3.64% (n = 6). The proposed method was applied to different water samples collected from a drinking water plant to determine the concentrations of haloacetic acids. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simultaneous determination of a variety of endocrine disrupting compounds in carrot, lettuce and amended soil by means of focused ultrasonic solid-liquid extraction and dispersive solid-phase extraction as simplified clean-up strategy.

Science.gov (United States)

Mijangos, L; Bizkarguenaga, E; Prieto, A; Fernández, L A; Zuloaga, O

2015-04-10

The present study is focused on the development of an analytical method based on focused ultrasonic solid-liquid extraction (FUSLE) followed by dispersive solid-phase extraction (dSPE) clean-up and liquid chromatography-triple quadrupole tandem mass spectrometry (LC-MS/MS) optimised for the simultaneous analysis of certain endocrine disrupting compounds (EDCs), including alkylphenols (APs), bisphenol A (BPA), triclosan (TCS) and several hormones and sterols in vegetables (lettuce and carrot) and amended soil samples. Different variables affecting the chromatographic separation, the electrospray ionisation and mass spectrometric detection were optimised in order to improve the sensitivity of the separation and detection steps. Under the optimised extraction conditions (sonication of 5min at 33% of power with pulse times on of 0.8s and pulse times off of 0.2s in 10mL of n-hexane:acetone (30:70, v:v) mixture using an ice bath), different dSPE clean-up sorbents, such as Florisil, Envi-Carb, primary-secondary amine bonded silica (PSA) and C18, or combinations of them were evaluated for FUSLE extracts before LC-MS/MS. Apparent recoveries and precision in terms of relative standard deviation (RSDs %) of the method were determined at two different fortification levels (according to the matrix and the analyte) and values in the 70-130% and 2-27% ranges, respectively, were obtained for most of the target analytes and matrices. Matrix-matched calibration approach and the use of labelled standards as surrogates were needed for the properly quantification of most analytes and matrices. Method detection limits (MDLs), estimated with fortified samples, in the ranges of 0.1-100ng/g for carrot, 0.2-152ng/g for lettuce and 0.9-31ng/g for amended soil were obtained. The developed methodology was applied to the analysis of 11 EDCs in both real vegetable bought in a local market and in compost (from a local wastewater treatment plant, WWTP) amended soil samples. Copyright © 2015

Simultaneous Determination of Perfluorinated Compounds in Edible Oil by Gel-Permeation Chromatography Combined with Dispersive Solid-Phase Extraction and Liquid Chromatography-Tandem Mass Spectrometry.

Science.gov (United States)

Yang, Lili; Jin, Fen; Zhang, Peng; Zhang, Yanxin; Wang, Jian; Shao, Hua; Jin, Maojun; Wang, Shanshan; Zheng, Lufei; Wang, Jing

2015-09-30

A simple analytical method was developed for the simultaneous analysis of 18 perfluorinated compounds (PFCs) in edible oil. The target compounds were extracted by acetonitrile, purified by gel permeation chromatography (GPC) and dispersive solid-phase extraction (DSPE) using graphitized carbon black (GCB) and octadecyl (C18), and analyzed by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ES-MS/MS) in negative ion mode. Recovery studies were performed at three fortification levels. The average recoveries of all target PFCs ranged from 60 to 129%, with an acceptable relative standard deviation (RSD) (1-20%, n = 3). The method detection limits (MDLs) ranged from 0.004 to 0.4 μg/kg, which was significantly improved compared with the existing liquid-liquid extraction and cleanup method. The method was successfully applied for the analysis of all target PFCs in edible oil samples collected from markets in Beijing, China, and the results revealed that C6-C10 perfluorocarboxylic acid (PFCAs) and C7 perfluorosulfonic acid PFSAs were the major PFCs detected in oil samples.

[Determination of patulin in fruits and jam by solid phase extraction-ultra performance liquid chromatography].

Science.gov (United States)

Lü, Weichao; Shen, Shuchang; Wang, Chao

2017-11-08

With magnesium silicate, silica gel, diatomite and calcium sulfate as raw materials, a new solid phase extraction column was prepared through a series of processes of grinding to ethanol homogenate, drying and packing into polypropylene tube. The sample was hydrolyzed by pectinase, extracted by acetonitrile and purified by solid phase extraction. The target compounds were separated on a C18 column (100 mm×2.1 mm, 1.8 μm), using 0.8% (v/v) tetrahydrofuran solution as mobile phase with a flow rate of 0.5 mL/min. The detection wavelength was 276 nm. The effect of pectinase on extraction yield and purification effect of solid-phase extraction column were investigated. The optimum chromatographic conditions were selected. There was a good linear relationship between the peak heights and the mass concentrations of patulin in the range of 0.1 to 10 mg/L with the correlation coefficient ( R 2 ) of 1. The limit of detection for this method was 10.22 μg/kg. The spiked recoveries of samples were 86.58%-94.84% with the relative standard deviations (RSDs) of 1.45%-2.28%. The results indicated that the self-made solid phase extraction column had a good purification efficiency, and the UPLC had a high separation efficiency. The method is simple, accurate and of great significance for the quality and safety control of fruit products.

Sensitive, automatic method for the determination of diazepam and its five metabolites in human oral fluid by online solid-phase extraction and liquid chromatography with tandem mass spectrometry

DEFF Research Database (Denmark)

Jiang, Fengli; Rao, Yulan; Wang, Rong

2016-01-01

A novel and simple online solid-phase extraction liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous determination of diazepam and its five metabolites including nordazepam, oxazepam, temazepam, oxazepam glucuronide, and temazepam glucuronide...... in human oral fluid. Human oral fluid was obtained using the Salivette(®) collection device, and 100 μL of oral fluid samples were loaded onto HySphere Resin GP cartridge for extraction. Analytes were separated on a Waters Xterra C18 column and quantified by liquid chromatography with tandem mass...

Experimental (solid + liquid) or (liquid + liquid) phase equilibria of (amine + nitrile) binary mixtures

International Nuclear Information System (INIS)

Domanska, Urszula; Marciniak, Malgorzata

2007-01-01

(Solid + liquid) phase diagrams have been determined for (hexylamine, or octylamine, or 1,3-diaminopropane + acetonitrile) mixtures. Simple eutectic systems have been observed in these mixtures. (Liquid + liquid) phase diagrams have been determined for (octylamine, or decylamine + propanenitrile, or + butanenitrile) mixtures. Mixtures with propanenitrile and butanenitrile show immiscibility in the liquid phase with an upper critical solution temperature, UCST. (Solid + liquid) phase diagrams have been correlated using NRTL, NRTL 1, Wilson and UNIQUAC equations. (Liquid + liquid) phase diagrams have been correlated using NRTL equation

Matrix solid-phase dispersion coupled with homogeneous ionic liquid microextraction for the determination of sulfonamides in animal tissues using high-performance liquid chromatography.

Science.gov (United States)

Wang, Zhibing; He, Mengyu; Jiang, Chunzhu; Zhang, Fengqing; Du, Shanshan; Feng, Wennan; Zhang, Hanqi

2015-12-01

Matrix solid-phase dispersion coupled with homogeneous ionic liquid microextraction was developed and applied to the extraction of some sulfonamides, including sulfamerazine, sulfamethazine, sulfathiazole, sulfachloropyridazine, sulfadoxine, sulfisoxazole, and sulfaphenazole, in animal tissues. High-performance liquid chromatography was applied to the separation and determination of the target analytes. The solid sample was directly treated by matrix solid-phase dispersion and the eluate obtained was treated by homogeneous ionic liquid microextraction. The ionic liquid was used as the extraction solvent in this method, which may result in the improvement of the recoveries of the target analytes. To avoid using organic solvent and reduce environmental pollution, water was used as the elution solvent of matrix solid-phase dispersion. The effects of the experimental parameters on recoveries, including the type and volume of ionic liquid, type of dispersant, ratio of sample to dispersant, pH value of elution solvent, volume of elution solvent, amount of salt in eluate, amount of ion-pairing agent (NH4 PF6 ), and centrifuging time, were evaluated. When the present method was applied to the analysis of animal tissues, the recoveries of the analytes ranged from 85.4 to 118.0%, and the relative standard deviations were lower than 9.30%. The detection limits for the analytes were 4.3-13.4 μg/kg. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Melted Paraffin Wax as an Innovative Liquid and Solid Extractant for Elemental Analysis by Laser-Induced Breakdown Spectroscopy.

Science.gov (United States)

Papai, Rodrigo; Sato, Roseli Hiromi; Nunes, Lidiane Cristina; Krug, Francisco José; Gaubeur, Ivanise

2017-03-07

This work proposes a new development in the use of melted paraffin wax as a new extractant in a procedure designed to aggregate the advantages of liquid phase extraction (extract homogeneity, fast, and efficient transfer, low cost and simplicity) to solid phase extraction. As proof of concept, copper(II) in aqueous samples was converted into a hydrophobic complex of copper(II) diethyldithiocarbamate and subsequently extracted into paraffin wax. Parameters which affect the complexation and extraction (pH, DDTC, and Triton X-100 concentration, vortex agitation time and complexation time) were optimized in a univariate way. The combination of the extraction proposed procedure with laser-induced breakdown spectroscopy allowed the precise copper determination (coefficient of variation = 3.1%, n = 10) and enhanced detectability because of the concentration factor of 18 times. A calibration curve was obtained with a linear range of 0.50-10.00 mg L -1 (R 2 = 0.9990, n = 7), LOD = 0.12 mg L -1 , and LOQ = 0.38 mg L -1 under optimized conditions. An extraction procedure efficiency of 94% was obtained. The accuracy of the method was confirmed through the analysis of a reference material of human blood serum, by the spike and recovery trials with seawater, tap water, mineral water, and alcoholic beverages and by comparing with those results obtained by graphite furnace atomic absorption spectrometry.

Combination of solvent extractants for dispersive liquid-liquid microextraction of fungicides from water and fruit samples by liquid chromatography with tandem mass spectrometry.

Science.gov (United States)

Pastor-Belda, Marta; Garrido, Isabel; Campillo, Natalia; Viñas, Pilar; Hellín, Pilar; Flores, Pilar; Fenoll, José

2017-10-15

A multiresidue method was developed to determine twenty-five fungicides belonging to three different chemical families, oxazoles, strobilurins and triazoles, in water and fruit samples, using dispersive liquid-liquid microextraction (DLLME) and liquid chromatography/tandem mass spectrometry (LC-MS 2 ). Solid-liquid extraction with acetonitrile was used for the analysis in fruits, the extract being used as dispersant solvent in DLLME. Since some of the analytes showed high affinity for chloroform and the others were more efficiently extracted with undecanol, a mixture of both solvents was used as extractant in DLLME. After evaporation of CHCl 3 , the enriched phase was analyzed. Enrichment factors in the 23-119 and 12-60 ranges were obtained for waters and fruits, respectively. The approach was most sensitive for metominostrobin with limits of quantification of 1ngL -1 and 5ngkg -1 in waters and fruits, respectively, while a similar sensitivity was attained for tebuconazole in fruits. Recoveries of the fungicides varied between 86 and 116%. Copyright © 2017 Elsevier Ltd. All rights reserved.

Liquid-liquid extraction in flow analysis: A critical review

Energy Technology Data Exchange (ETDEWEB)

Silvestre, Cristina I.C.; Santos, Joao L.M. [REQUIMTE, Servico de Quimica-Fisica, Faculdade de Farmacia, Universidade do Porto, R. Anibal Cunha, 164, 4099-030 Porto (Portugal); Lima, Jose L.F.C., E-mail: limajlfc@ff.up.pt [REQUIMTE, Servico de Quimica-Fisica, Faculdade de Farmacia, Universidade do Porto, R. Anibal Cunha, 164, 4099-030 Porto (Portugal); Zagatto, Elias A.G. [Centro de Energia Nuclear na Agricultura, Universidade de Sao Paulo, P.O. Box 96, Piracicaba 13400-970 (Brazil)

2009-10-12

Liquid-liquid extractions (LLE) are a common sample pre-treatment in many analytical applications. This review aims at providing a critical overview of the distinct automated continuous flow-based approaches that were developed for liquid-liquid extraction with the purpose of pre-concentration and/or separation of multiple analytes, such as ultra-trace metal and metalloid species, phenolic compounds, surfactants, pharmaceuticals, etc., hyphenated with many detection technique such as UV/vis spectrophotometry, atomic spectrometric detection systems and luminescent detectors, including distinct extraction strategies and applications like single and multiple extraction schemes, wetting film extraction, supported liquid membrane extraction, back extraction, closed-loop systems and the utilisation of zone sampling, chromatomembranes and iterative reversal techniques. The analytical performance of the developed flow-based LLE methods and the influence of flow manifold components such as the segmenter, extraction coil and phase separator, is emphasised and object of discussion. An overall presentation of each system components, selectivity, advantages and shortcomings is carried out and exemplified with selected applications.

The use of ultrasonic instrumentation in liquid/liquid extraction plant

International Nuclear Information System (INIS)

Asher, R.C.; Bradshaw, L.; Tolchard, A.C.

1984-01-01

Ultrasonic instruments can be used to determine many of the parameters of interest in a liquid/liquid extraction plant, eg liquid levels, the position of interfaces between immiscible liquids and the concentration of solutions. The determinations can often be made non-invasively. A number of instruments developed for a liquid/liquid extraction plant used for nuclear fuel reprocessing is described. These instruments have a wider application in liquid/liquid extraction plant in general. (author)

Dispersive solid phase micro-extraction of mercury(II from environmental water and vegetable samples with ionic liquid modified graphene oxide nanoparticles

Directory of Open Access Journals (Sweden)

Nasrollahpour Atefeh

2017-01-01

Full Text Available A new dispersive solid phase micro-extraction (dispersive-SPME method for separation and preconcentration of mercury(II using ionic liquid modified magnetic reduced graphene oxide (IL-MrGO nanoparticles, prior to the measurement by cold vapour atomic absorption spectrometry (CV-AAS has been developed. The IL-MrGO composite was characterized by Brunauer– Emmett–Teller method (BET for adsorption-desorption measurement, thermogravimetric analysis (TGA, powder X-ray diffraction (XRD and X-ray photoelectron spectroscopy (XPS. The method is based on the sorption of mercury( II on IL-MrGO nanoparticles due to electrostatic interaction and complex formation of ionic liquid part of IL-MrGO with mercury(II. The effect of experimental parameters for preconcentration of mercury(II, such as solution type, concentration and volume of the eluent, pH, time of the sorption and desorption, amount of the sorbent and coexisting ion concentration have been optimized. Under the optimized conditions, a linear response was obtained in the concentration range of 0.08–10 ng mL-1 with a determination coefficient of 0.9995. The limit of detection (LOD of the method at a signal to noise ratio of 3 was 0.01 ng mL-1. Intra-day and inter-day precisions were obtained equal to 3.4 and 4.5 %, respectively. The dispersive solid phase micro-extraction of mercury(II on IL-MrGO nanoparticles coupled with cold vapour atomic absorption spectrometry was successfully used for extraction and determination of mercury(II in water and vegetable samples.

Ion-exchange solid-phase extraction combined with liquid chromatography-tandem mass spectrometry for the determination of veterinary drugs in organic fertilizers.

Science.gov (United States)

Zhao, Zhiyong; Zhang, Yanmei; Xuan, Yanfang; Song, Wei; Si, Wenshuai; Zhao, Zhihui; Rao, Qinxiong

2016-06-01

The analysis of veterinary drugs in organic fertilizers is crucial for an assessment of potential risks to soil microbial communities and human health. We develop a robust and sensitive method to quantitatively determine 19 veterinary drugs (amantadine, sulfonamides and fluoroquinolones) in organic fertilizers. The method involved a simple solid-liquid extraction step using the combination of acetonitrile and McIlvaine buffer as extraction solvent, followed by cleanup with a solid-phase extraction cartridge containing polymeric mixed-mode anion-exchange sorbents. Ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was used to separate and detect target analytes. We particularly focused on the optimization of sample clean-up step: different diluents and dilution factors were tested. The developed method was validated in terms of linearity, recovery, precision, sensitivity and specificity. The recoveries of all the drugs ranged from 70.9% to 112.7% at three concentration levels, with the intra-day and inter-day relative standard deviation lower than 15.7%. The limits of quantification were between 1.0 and 10.0μg/kg for all the drugs. Matrix effect was minimized by matrix-matched calibration curves. The analytical method was successfully applied for the survey of veterinary drugs contamination in 20 compost samples. The results indicated that fluoroquinolones had higher incidence rate and mean concentration levels ranging from 31.9 to 308.7μg/kg compared with other drugs. We expect the method will provide the basis for risk assessment of veterinary drugs in organic fertilizers. Copyright © 2016 Elsevier B.V. All rights reserved.

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.

Dispersive liquid-liquid microextraction coupled with magnetic nanoparticles for extraction of zearalenone in wheat samples

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Mitra Amoli-Diva

2017-01-01

Full Text Available A new, sensitive and fast dispersive liquid-liquid microextraction (DLLME coupled with micro-solid phase extraction (μ-SPE was developed for determination of zearalenone (ZEN in wheat samples. The DLLME was performed using acetonitrile/water (80:20 v/v as the disperser solvent and 1-octanol as the extracting solvent.  The acetonitrile/water (80:20 v/v solvent was also used to extract ZEN from solid wheat matrix, and was directly applied as the disperser solvent for DLLME process. Additionally, hydrophobic oleic-acid-modified magnetic nanoparticles were used in μ-SPE approach to retrieve the analyte from the DLLME step. So, the method uses high surface area and strong magnetism properties of these nanoparticles to avoid time-consuming column-passing processes in traditional SPE. Main parameters affecting the extraction efficiency and signal enhancement were investigated and optimized. Under the optimum conditions, the calibration curve showed a good linearity in the range of 0.1-500 μg kg−1 (R2=0.9996 with low detection limit of 83 ng g−1. The intra-day and inter-day precisions (as RSD % in the range of 2.6-4.3 % and high recoveries ranging from 91.6 to 99.1 % were obtained. The pre-concentration factor was 3. The method is simple, inexpensive, accurate and remarkably free from interference effects.

Salting-out homogenous extraction followed by ionic liquid/ionic liquid liquid-liquid micro-extraction for determination of sulfonamides in blood by high performance liquid chromatography.

Science.gov (United States)

Liu, Zhongling; Yu, Wei; Zhang, Hanqi; Gu, Fanbin; Jin, Xiangqun

2016-12-01

Salting-out homogenous extraction followed by ionic liquid/ionic liquid dispersive liquid-liquid micro-extraction system was developed and applied to the extraction of sulfonamides in blood. High-performance liquid chromatography was applied to the determination of the analytes. The blood sample was centrifuged to obtain the serum. After the proteins in the serum were removed in the presence of acetonitrile, ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate, dipotassium hydrogen phosphate, ionic liquid 1-Hexyl-3-methylimidazolium hexafluorophosphate were added into the resulting solution. After the resulting mixture was ultrasonically shaken and centrifuged, the precipitate was separated. The acetonitrile was added in the precipitate and the analytes were extracted into the acetonitrile phase. The parameters affecting the extraction efficiency, such as volume of ionic liquid, amount of dipotassium hydrogen phosphate, volume of dispersant, extraction time and temperature were investigated. The limits of detection of sulfamethizole (STZ), sulfachlorpyridazine (SCP), sulfamethoxazole (SMX) and Sulfisoxazole (SSZ) were 4.78, 3.99, 5.21 and 3.77μgL -1 , respectively. When the present method was applied to the analysis of real blood samples, the recoveries of analytes ranged from 90.0% to 113.0% and relative standard deviations were lower than 7.2%. Copyright © 2016 Elsevier B.V. All rights reserved.

LIQUID-LIQUID EXTRACTION COLUMNS

Science.gov (United States)

Thornton, J.D.

1957-12-31

This patent relates to liquid-liquid extraction columns having a means for pulsing the liquid in the column to give it an oscillatory up and down movement, and consists of a packed column, an inlet pipe for the dispersed liquid phase and an outlet pipe for the continuous liquid phase located in the direct communication with the liquid in the lower part of said column, an inlet pipe for the continuous liquid phase and an outlet pipe for the dispersed liquid phase located in direct communication with the liquid in the upper part of said column, a tube having one end communicating with liquid in the lower part of said column and having its upper end located above the level of said outlet pipe for the dispersed phase, and a piston and cylinder connected to the upper end of said tube for applying a pulsating pneumatic pressure to the surface of the liquid in said tube so that said surface rises and falls in said tube.

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.

Comparison between 2 methods of solid-liquid extraction for the production of Cinchona calisaya elixir: an experimental kinetics and numerical modeling approach.

Science.gov (United States)

Naviglio, Daniele; Formato, Andrea; Gallo, Monica

2014-09-01

The purpose of this study is to compare the extraction process for the production of China elixir starting from the same vegetable mixture, as performed by conventional maceration or a cyclically pressurized extraction process (rapid solid-liquid dynamic extraction) using the Naviglio Extractor. Dry residue was used as a marker for the kinetics of the extraction process because it was proportional to the amount of active principles extracted and, therefore, to their total concentration in the solution. UV spectra of the hydroalcoholic extracts allowed for the identification of the predominant chemical species in the extracts, while the organoleptic tests carried out on the final product provided an indication of the acceptance of the beverage and highlighted features that were not detectable by instrumental analytical techniques. In addition, a numerical simulation of the process has been performed, obtaining useful information about the timing of the process (time history) as well as its mathematical description. © 2014 Institute of Food Technologists®

The determination of organochlorine pesticides based on dynamic microwave-assisted extraction coupled with on-line solid-phase extraction of high-performance liquid chromatography

International Nuclear Information System (INIS)

Chen Ligang; Ding Lan; Jin Haiyan; Song Daqian; Zhang Huarong; Li Jiantao; Zhang Kun; Wang Yutang; Zhang Hanqi

2007-01-01

A rapid technique based on dynamic microwave-assisted extraction coupled with on-line solid-phase extraction of high-performance liquid chromatography (DMAE-SPE-HPLC) has been developed. A TM 010 microwave resonance cavity built in the laboratory was applied to concentrate the microwave energy. The sample placed in the zone of microwave irradiation was extracted with 95% acetonitrile (ACN) aqueous solution which was driven by a peristaltic pump at a flow rate of 1.0 mL min -1 . The extraction can be completed in a recirculating system in 10 min. When a number of extraction cycles were completed, the extract (1 mL) was diluted on-line with water. Then the extract was loaded into an SPE column where the analytes were retained while the unretained matrix components were washed away. Subsequently, the analytes were automatically transferred from the SPE column to the analytical column and determined by UV detector at 238 nm. The technique was used for determination of organochlorine pesticides (OCPs) in grains, including wheat, rice, corn and bean. The limits of detection of OCPs are in the range of 19-37 ng g -1 . The recoveries obtained by analyzing the four spiked grain samples are in the range of 86-105%, whereas the relative standard deviation (R.S.D.) values are <8.7% ranging from 1.2 to 8.7%. Our method was demonstrated to be fast, accurate, and precise. In addition, only small quantities of solvent and sample were required

Gastric emptying of a physiologic mixed solid-liquid meal

Energy Technology Data Exchange (ETDEWEB)

Fisher, R.S.; Malmud, L.S.; Bandini, P.; Rock, E.

1982-05-01

The purposes of this study were to use a noninvasive scintigraphic technique to measure gastric emptying of liquids and solids simultaneously, to study the interactions between emptying of the liquid and solid components of meals in normal subjects, and to employ dual isotope gastric scintigraphy to evaluate gastric emptying of liquids and solids in patients with clinical evidence of gastric outlet obstruction. The solid component of the test meal consisted of chicken liver, labeled in vivo with /sup 99m/Tc sulfur colloid, and the liquid component was water mixed with /sup 111/In DTPA. The rates of emptying were quantitated using a gamma camera on line to a digital computer. Twenty normal subjects were studied using this combined solid-liquid meal. Ten of them also ingested a liquid meal alone and ten a solid meal alone. Liquid emptied from the stomach significantly more rapidly than did solids. The emptying curve for liquids was exponential compared to a linear emptying curve for solids. The gastric emptying rate of the liquid component was slowed significantly by simultaneous ingestion of solids, but the emptying rate of solids was not affected by liquids. Several patients with clinical gastric outlet obstruction were evaluated. Both combined and selective abnormalities for gastric emptying of liquids and solids were demonstrated.

Laboratory studies of the behavior of undissolved solids in both pulsed and packed column extraction systems

International Nuclear Information System (INIS)

Siemer, D.D.

1989-01-01

A substantial fraction of the finely divided undissolved solid material found in nuclear fuel reprocessing dissolver-product solutions is hydrophobic and tends to ''seek'' any organic-aqueous interface existing within countercurrent liquid-liquid extraction systems. While passing through pulsed-type columns this material is swept out of the aqueous phase by the combined surface area of the tiny bubbles of dispersed phase. Because these bubbles have a net velocity towards the end of the column where the nominal interface is located, the solids are swept in that direction too. These solids tend to gather in a three-phase ''crud'' layer at the nominal interface point. At equilibrium, about the same amount breaks off from the crud layer and escapes into the liquid exiting from that end of the column as enters it from the other side. If large enough, the crud layer can even interfere with interface detection and control equipment. In packed-column extraction systems, an additional problem is that feed solids can accumulate within the packing material to the point that the column '' floods'' or even totally plugs. The keys to preventing solids-related problems is the correct choice of interface level, and with packed columns, the addition of a ''pulsing leg'' at the bottom of the column. Pulsing packed column systems not only prevents solids from settling onto packing material but it also increses the number of theoretical stages available for extraction. 3 figs., 2 tabs

COMPARISONS OF SOXHLET EXTRACTION, PRESSURIZED LIQUID EXTRACTION, SUPERCRITICAL FLUID EXTRACTION, AND SUBCRITICAL WATER EXTRACTION FOR ENVIRONMENTAL SOLIDS: RECOVERY, SELECTIVITY, AND EFFECTS ON SAMPLE MATRIX. (R825394)

Science.gov (United States)

Extractions of a polycyclic aromatic hydrocarbon (PAH)-contaminated soil from a former manufactured gas plant site were performed with a Soxhlet apparatus (18 h), by pressurized liquid extraction (PLE) (50 min at 100°C), supercritical fluid extraction (SFE) (1 h at 150°...

Broadband luminescence in liquid-solid transition

CERN Document Server

Achilov, M F; Trunilina, O V

2002-01-01

Broadband luminescence (BBL) intensity behavior in liquid-solid transition in polyethyleneglycol-600 has been established. Oscillation of BBL intensity observed in liquid-polycrystal transition are not found to observed in liquid-amorphous solid transition. It is shown that application of the theory of electron state tails to interpretation of BBL spectral properties in liquids demands restriction. BBL spectroscopy may be applied for optimization of preparation of polymers with determined properties. (author)

Contacting particulate solids with liquids

International Nuclear Information System (INIS)

Hodgson, T.D.

1980-01-01

Apparatus is described for contacting particulate solids with a fluid. The particular applications described are 1) an acid dissolver for dissolving plutonium from plutonium contaminated ash produced by the incineration of waste such as rubber gloves, tissue paper etc. and 2) apparatus for dissolving gel spheres of nuclear fuel material. The liquid, e.g. acid for use in a leaching process flows through a vertical conduit and past a series of baffles spaced along the axis of the conduit. Each baffle defines a mixing chamber and provides a small gap around its perimeter between the baffle and the wall of the conduit. The baffles are provided with sloping top surfaces for preventing solid particles from settling on the baffles and sloping undersurfaces to improve mixing of the liquid and the solid particles. The liquid flows upwards in the conduit but solid particles may be fed from the top or from the bottom of the conduit to mix with the liquid. Gas may be introduced to promote improved flow conditions. (U.K.)

General aspects of solid on liquid growth mechanisms

International Nuclear Information System (INIS)

Laux, E; Charmet, J; Haquette, H; Banakh, O; Jeandupeux, L; Graf, B; Keppner, H

2009-01-01

Liquids, in general, tend to have a lower density as solids and therefore it is not straightforward to deposit solid over liquids in a way that the liquid becomes hermetically sealed under the solid layer. The authors review that several phenomena that can easily be observed in nature are only due to particular anomalies and solid on liquid is rather an exception as the rule. Natural solid on liquid systems are lacking of thermal, mechanical or chemical stability. It is not surprising, that one is not at all used thinking about to e.g. replace the gate oxide in a thin film transistor by a thin film of oil, or, to find in other microsystems functional liquids between a stack of thin solid films. However, once this becomes a serious option, a large variety of new Microsystems with new functionalities can be easily designed. In another paper (this conference and [1]) the authors pioneered that the polymer Parylene (poly(p-xylylene)) can be deposited on liquids coming already quite close to the above mentioned vision. In this paper the authors ask if one can synthesize other solid on liquid systems and surprisingly conclude, based on experimental evidence, that solid on liquid deposition seems to rather be the rule and not the exception.

Suspended solids in liquid effluents

International Nuclear Information System (INIS)

McGrath, J.J.

1988-06-01

An international literature review and telephone mail survey was conducted with respect to technical and regulatory aspects of suspended solids in radioactive liquid wastes from nuclear power stations. Results of the survey are summarized and show that suspended solids are an important component of some waste streams. The data available, while limited, show these solids to be associated largely with corrosion products. The solids are highly variable in quantity, size and composition. Filtration is commonly applied for their removal from liquid effluents and is effective. Complex interactions with receiving waters can result in physical/chemical changes of released radionuclides and these phenomena have been seen as reason for not applying regulatory controls based on suspended solids content. 340 refs

Simultaneous Detection of Sulfamethoxazole, Diclofenac, Carbamazepine, and Bezafibrate by Solid Phase Extraction and High Performance Liquid Chromatography with Diode Array Detection

Science.gov (United States)

Zhou, Z.; Jiang, J.-Q.

2014-05-01

A method of solid phase extraction (SPE) coupled with high performance liquid chromatography and diode array detection (HPLC-DAD) was studied for the simultaneous determination of sulfamethoxazole (SMX), diclofenac (DCF), carbamazepine (CBZ), and bezafi brate (BZF) in test solutions. The target compounds were extracted by SPE from samples, and the resulting elutes were analyzed using a HPLC-DAD system at wavelengths of 270, 280, 290, and 230 nm for SMX, DCF, CBZ, and BZF, respectively. This method shows good recoveries for SMX, DCF, CBZ, and BZF with mean recoveries of 89.7 ± 9.3%, 86.1 ± 7.6%, 95.0 ± 6.5%, and 94.0 ± 5.4%, respectively.

Solid phase extraction of Am (III) by resins impregnated with multiply diglycolamide-functionalized ligands

International Nuclear Information System (INIS)

Gujar, R.B.; Ansari, S.A.; Mohapatra, P.K.; Verboom, W.

2016-01-01

Solvent extraction studies with multiply diglycolamide-functionalized extractants such as tripodal diglycolamide (T-DGA) or diglycolamide-functionalized calix(4)arene (C4DGA) ligands have shown excellent results as compared to those of normal DGA ligands such as TODGA. A very high selectivity for Am(III) has been reported with these ligands with respect to U(VI) and Pu(IV). High selectivities and large extraction efficiencies of these ligands towards trivalent f elements were ascribed to a co-operative complexation mechanism. Furthermore, the extraction efficiency of these ligands increased several folds in ionic liquid medium as compared to paraffinic solvents. It was of interest, therefore, to prepare extraction chromatographic resins by impregnation of solvent systems containing these ligands in an ionic liquid. In the present work, solid phase extraction studies were carried out using these two multiply diglycolamide-functionalized extractants, viz. T-DGA (resin I) and C4DGA (resin-II) containing the ionic liquid C 4 mim. NTf 2 impregnated on Chromosorb-W

[Corrected Title: Solid-Phase Extraction of Polar Compounds from Water] Automated Electrostatics Environmental Chamber

Science.gov (United States)

Sauer, Richard; Rutz, Jeffrey; Schultz, John

2005-01-01

A solid-phase extraction (SPE) process has been developed for removing alcohols, carboxylic acids, aldehydes, ketones, amines, and other polar organic compounds from water. This process can be either a subprocess of a water-reclamation process or a means of extracting organic compounds from water samples for gas-chromatographic analysis. This SPE process is an attractive alternative to an Environmental Protection Administration liquid-liquid extraction process that generates some pollution and does not work in a microgravitational environment. In this SPE process, one forces a water sample through a resin bed by use of positive pressure on the upstream side and/or suction on the downstream side, thereby causing organic compounds from the water to be adsorbed onto the resin. If gas-chromatographic analysis is to be done, the resin is dried by use of a suitable gas, then the adsorbed compounds are extracted from the resin by use of a solvent. Unlike the liquid-liquid process, the SPE process works in both microgravity and Earth gravity. In comparison with the liquid-liquid process, the SPE process is more efficient, extracts a wider range of organic compounds, generates less pollution, and costs less.

IN SITU SOLID-PHASE EXTRACTION AND ANALYSIS OF ...

Science.gov (United States)

Fragrance materials, such as synthetic musks in aqueous samples, are normally analyzed by GC/MS in the selected ion monitoring (SIM) mode to provide maximum sensitivity after liquid-liquid extraction of 1-L samples. A 1-L sample, however, usually provides too little analyte for full-scan data acquisition.We have developed an on-site extraction method for extracting synthetic musks from 60 L of wastewater effluent. Such a large sample volume permits high-quality, full-scan mass spectra to be obtained for various synthetic musk compounds. Quantification of these compounds was conveniently achieved from the full-scan data directly, without preparing SIM descriptors for each compound to acquire SIM data. The research focused on in the subtasks is the development and application of state-of the-art technologies to meet the needs of the public, Office of Water, and ORD in the area of Water Quality. Located In the subtasks are the various research projects being performed in support of this Task and more in-depth coverage of each project. Briefly, each project's objective is stated below.Subtask 1: To integrate state-of-the-art technologies (polar organic chemical integrative samplers, advanced solid-phase extraction methodologies with liquid chromatography/electrospray/mass spectrometry) and apply them to studying the sources and fate of a select list of PPCPs. Application and improvement of analytical methodologies that can detect non-volatile, polar, water-s

Extraction of functional ingredients from spinach (Spinacia oleracea L.) using liquid solvent and supercritical CO₂ extraction.

Science.gov (United States)

Jaime, Laura; Vázquez, Erika; Fornari, Tiziana; López-Hazas, María del Carmen; García-Risco, Mónica R; Santoyo, Susana; Reglero, Guillermo

2015-03-15

In this work three different techniques were applied to extract dry leaves of spinach (Spinacia oleracea): solid-liquid extraction (SLE), pressurised liquid extraction (PLE) and supercritical fluid extraction (SFE) to investigate the influence of extraction solvent and technique on extracts composition and antioxidant activity. Moreover, the influence of carotenoids and phenolic compounds on the antioxidant and anti-inflammatory activities of spinach extracts was also studied. The higher concentrations of carotenoids and the lower content of phenolic compounds were observed in the supercritical CO₂ extracts; whereas water and/or ethanol PLE extracts presented low amounts of carotenoids and the higher concentrations of phenolic compounds. PLE extract with the highest content of phenolic compounds showed the highest antioxidant activity, although SFE carotenoid rich extract also showed a high antioxidant activity. Moreover, both extracts presented an important anti-inflammatory activity. PLE seems to be a good technique for the extraction of antioxidant and anti-inflammatory compounds from spinach leaves. Moreover, spinach phenolic compounds and carotenoids present a high antioxidant activity, whereas spinach carotenoids seem to show a higher anti-inflammatory activity than phenolic compounds. It is worth noting that of our knowledge this is the first time the anti-inflammatory activity of lipophilic extracts from spinach leaves is reported. © 2014 Society of Chemical Industry.

Membrane assisted liquid-liquid extraction of cerium

International Nuclear Information System (INIS)

Soldenhoff, K.M.

2000-02-01

Membrane assisted liquid-liquid extraction of cerium was investigated, with emphasis placed on the study of the reaction chemistry and the kinetics of non-dispersive solvent extraction and stripping with microporous membranes. A bulk liquid membrane process was developed for the purification of cerium(IV) from sulfate solutions containing other rare earth elements. The cerium process was studied in both a flat sheet contained liquid membrane configuration and with hollow fibre contactors. Di-2-ethylhexyl phosphoric acid (DEHPA) was identified as a suitable extractant for cerium(IV) from sulfuric acid solution, with due consideration of factors such as extraction ability, resistance to degradation, solvent selectivity and potential for sulfate transfer into a strip solution. A detailed study of the extraction of cerium(IV) with DEHPA defined the extraction reaction chemistry. The Ce/DEHPA/sulfate system was also investigated with a flat sheet bulk liquid membrane configuration, using both sulfuric and hydrochloric acid as receiver solutions. These tests identified that hydrophobic membranes provide better mass transfer for extraction and hydrophilic membranes are better for stripping. The presence of an impurity, mono 2-ethylhexyl phosphoric acid (MEHPA), was found to have a dramatic accelerating effect on the rate of the chemical extraction reaction. This was attributed to its higher interfacial activity and population compared to DEHPA, and the fact that MEHPA was also found to be an active carrier for cerium(IV). The mass transfer rate of membrane assisted extraction and stripping of cerium, using hydrophobic and hydrophilic microporous membranes, respectively, was investigated using a modified Lewis-type cell. It was quantitatively demonstrated that the extraction process was mainly controlled by membrane diffusion and the stripping process was controlled by the chemical reaction rate, with membrane diffusion becoming important at low distribution coefficients

Improved resins and novel materials and methods for solid phase extraction and high performance liquid chromatography

Energy Technology Data Exchange (ETDEWEB)

Freeze, Ronald [Iowa State Univ., Ames, IA (United States)

1997-10-08

Solid-phase extraction (SPE) has grown to be one of the most widely used methods for isolation and preconcentration of a vast range of compounds from aqueous solutions. By modifying polymeric SPE resins with chelating functional groups, the selective uptake of metals was accomplished. The resin, along with adsorbed metals, was vaporized in the ICP and detection of the metals was then possible using either mass or emission spectroscopy. Drug analyses in biological fluids have received heightened attention as drug testing is on the increase both in sports and in the work environment. By using a direct-injection technique, biological fluids can be injected directly into the liquid chromatographic system with no pretreatment. A new surfactant, a sulfonated form of Brij-30 (Brij-S) is shown to prevent the uptake of serum proteins on commercial HPLC columns by forming a thin coating on the silica C18 surface. Excellent separations of eight or more drugs with a wide range of retention times were obtained. The separations had sharper peaks and lower retention times than similar separations performed with the surfactant sodium dodecylsulfate (SDS). Quantitative recovery of a number of drugs with limits of detection near 1 ppm with a 5 μl injection volume were obtained. Finally, a method for solid-phase extraction in a syringe is introduced. The system greatly reduced the volume of solvent required to elute adsorbed analytes from the SPE bed while providing a semi-automated setup. SPE in a syringe consists of a very small bed of resin-loaded membrane packed into a GC or HPLC syringe. After extraction, elution was performed with just a few μl of solvent. This small elution volume allowed injection of the eluent directly from the syringe into the chromatographic system, eliminating the handling problems associated with such small volumes.

Polymer liquids fracture like solids

DEFF Research Database (Denmark)

Huang, Qian; Hassager, Ole

2017-01-01

While fracture in brittle solids has been studied for centuries until today, there are few studies on fracture in polymer liquids. Recent developments in experimental techniques, especially the combination of controlled filament stretching rheometry and high speed imaging, have opened new windows...... into the detailed study of fracture processes for polymer liquids. High speed imaging shows that polymer liquids fracture like solids with initiation and propagation of an edge fracture. However, remarkable features such as highly reproducible critical stress, independent appearance of multiple fractures...

Solid-Liquid and Liquid-Liquid Equilibrium in the Formamide-Acetophenone System.

Czech Academy of Sciences Publication Activity Database

Malijevská, I.; Sedláková, Zuzana; Řehák, K.; Vrbka, P.

2006-01-01

Roč. 71, 9 (2006) , s. 1350-1358 ISSN 0010-0765 Institutional research plan: CEZ:AV0Z40720504 Keywords : solid-liquid equilibria * liquid-liquid equilibria * metastable Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.881, year: 2006

Application of ionic liquid for extraction and separation of bioactive compounds from plants.

Science.gov (United States)

Tang, Baokun; Bi, Wentao; Tian, Minglei; Row, Kyung Ho

2012-09-01

In recent years, ionic liquids (ILs), as green and designer solvents, have accelerated research in analytical chemistry. This review highlights some of the unique properties of ILs and provides an overview of the preparation and application of IL or IL-based materials to extract bioactive compounds in plants. IL or IL-based materials in conjunction with liquid-liquid extraction (LLE), ultrasonic-assisted extraction (UAE), microwave-assisted extraction (MAE), high performance liquid chromatography (HPLC) and solid-phase extraction (SPE) analytical technologies etc., have been applied successfully to the extraction or separation of bioactive compounds from plants. This paper reviews the available data and references to examine the advantages of IL and IL-based materials in these applications. In addition, the main target compounds reviewed in this paper are bioactive compounds with multiple therapeutic effects and pharmacological activities. Based on the importance of the targets, this paper reviews the applications of ILs, IL-based materials or co-working with analytical technologies. The exploitation of new applications of ILs on the extraction of bioactive compounds from plant samples is expected to increase. Copyright © 2012 Elsevier B.V. All rights reserved.

Stiffening solids with liquid inclusions

Science.gov (United States)

Style, Robert W.; Boltyanskiy, Rostislav; Allen, Benjamin; Jensen, Katharine E.; Foote, Henry P.; Wettlaufer, John S.; Dufresne, Eric R.

2015-01-01

From bone and wood to concrete and carbon fibre, composites are ubiquitous natural and synthetic materials. Eshelby’s inclusion theory describes how macroscopic stress fields couple to isolated microscopic inclusions, allowing prediction of a composite’s bulk mechanical properties from a knowledge of its microstructure. It has been extended to describe a wide variety of phenomena from solid fracture to cell adhesion. Here, we show experimentally and theoretically that Eshelby’s theory breaks down for small liquid inclusions in a soft solid. In this limit, an isolated droplet’s deformation is strongly size-dependent, with the smallest droplets mimicking the behaviour of solid inclusions. Furthermore, in opposition to the predictions of conventional composite theory, we find that finite concentrations of small liquid inclusions enhance the stiffness of soft solids. A straightforward extension of Eshelby’s theory, accounting for the surface tension of the solid-liquid interface, explains our experimental observations. The counterintuitive stiffening of solids by fluid inclusions is expected whenever inclusion radii are smaller than an elastocapillary length, given by the ratio of the surface tension to Young’s modulus of the solid matrix. These results suggest that surface tension can be a simple and effective mechanism to cloak the far-field elastic signature of inclusions.

Separation of uranium(VI) by liquid-solid extraction with tri-n-octylphosphine oxide diluted with naphthalene

International Nuclear Information System (INIS)

Shigetomi, Y.; Kojima, T.; Kamba, H.; Yamamoto, Y.

1980-01-01

Liquid-liquid distribution with tri-n-octylphosphine oxide (TOPO) and molten naphthalene has been investigated for the extraction of 20 metals from nitric acid and hydrochloric acid solutions. Uranium is quantitatively extracted from 1 M nitric acid or hydrochloric acid by using 100 mg of TOPO and 200 mg of naphthalene and shaking for 5 min at 80 0 C, and separated from transition metals, alkaline earth metals and rare earth metals (except scandium). Addition of naphthalene increases the extraction efficiency. (Auth.)

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.

Magnetic dispersive solid-phase extraction based on modified magnetic nanoparticles for the detection of cocaine and cocaine metabolites in human urine by high-performance liquid chromatography-mass spectrometry.

Science.gov (United States)

Yang, Feiyu; Zou, Yun; Ni, Chunfang; Wang, Rong; Wu, Min; Liang, Chen; Zhang, Jiabin; Yuan, Xiaoliang; Liu, Wenbin

2017-11-01

An easy-to-handle magnetic dispersive solid-phase extraction procedure was developed for preconcentration and extraction of cocaine and cocaine metabolites in human urine. Divinyl benzene and vinyl pyrrolidone functionalized silanized Fe 3 O 4 nanoparticles were synthesized and used as adsorbents in this procedure. Scanning electron microscopy, vibrating sample magnetometry, and infrared spectroscopy were employed to characterize the modified adsorbents. A high-performance liquid chromatography with mass spectrometry method for determination of cocaine and its metabolites in human urine sample has been developed with pretreatment of the samples by magnetic dispersive solid-phase extraction. The obtained results demonstrated the higher extraction capacity of the prepared nanoparticles with recoveries between 75.1 to 105.7% and correlation coefficients higher than 0.9971. The limits of detection for the cocaine and cocaine metabolites were 0.09-1.10 ng/mL. The proposed magnetic dispersive solid-phase extraction method provided a rapid, environmentally friendly and magnetic stuff recyclable approach and it was confirmed that the prepared adsorbents material was a kind of highly effective extraction materials for the trace cocaine and cocaine metabolites analyses in human urine. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Study of ion separation through solid-supported liquid membrane

International Nuclear Information System (INIS)

Kang, Young Ho; Kim, Jung Do; Kim, Kyoung Ho

1990-01-01

The membranes used in this study consist of a microporous polymeric support with the solvent contraining alamine 336, Tri-N-Octyl phosphine oxide, Tri-N-butyl phosphate, Di-(2-ethylhexyl) phosphoric acid as a carrier within the pores by the capillary forces. When this liquid membrane is interposed between aqueous feed and product solutions, the carrier serving as a complexing agent, can pick up the uranium ions on the feed side of the membrane and carry them across the membrane by diffusion. In this study, the uranium flux through the solid-supported liquid membrane was analyzed as a function of carrier concentration and acidity of the feed solution for the carrier species. Also, the Gel-liquid extraction of uranium ions from aqueous solution was performed. The adsorbents were prepared by casting the polymer solution composed of polyvinyl chloride, TOPO, and additions. The extraction of uranyl nitrate ions has been investigated as a function of TOPO/PVC ratio, evaporation time, and the stability. The results show that is maybe possible to develop an alternative uranium purification process. (author)

Molecularly Imprinted Polymers (MIP for Selective Solid Phase Extraction of Celecoxib in Urine Samples Followed by High Performance Liquid Chromatography

Directory of Open Access Journals (Sweden)

Saeedeh Ansari

2017-09-01

Full Text Available In this study, for the analysis of human urine samples, a novel method explained for the determination of celecoxib, a nonsteroidal anti-inflammatory drug (NSAID, using molecularly imprinted solid-phase extraction (MISPE coupled with high-performance liquid chromatography (HPLC. The synthesis of the MIP was performed by precipitation polymerization in methacrylic acid (MAA, ethylene glycol dimethacrylate (EGDMA, chloroform, 2,2′-azobisisobutyronitrile (AIBN and celecoxib as the functional monomer, cross-linker monomer, solvent, initiator and target drug, respectively. The celecoxib imprinted polymer was utilized as a specific sorbent for the solid phase extraction (SPE of celecoxib from samples. The molecularly imprinted polymer (MIP performance was compared with the synthesized non-molecularly imprinted polymer (NIP. Scanning electron microscopy (SEM, FT-IR spectroscopy, UV-VIS spectrophotometry and thermogravimetric analysis (TGA/DTG were used for characterizing the synthesized polymers. Moreover, the MISPE procedure parameters such as pH, eluent solvent flow rate, eluent volume and sorbent mass that probably influence the extraction process have been optimized to achieve the highest celecoxib extraction efficiency. The relative standard deviation (RSD %, recovery percent, limit of detection (LOD and limit of quantification (LOQ of this proposed method were 1.12%, 96%, 8 µg L-1 and 26.7 µg L-1, respectively. The proposed MISPE-HPLC-UV method can be used for the separation and enrichment of trace amounts of celecoxib in human urine and biological samples.

Multi-residue determination of the sorption of illicit drugs and pharmaceuticals to wastewater suspended particulate matter using pressurised liquid extraction, solid phase extraction and liquid chromatography coupled with tandem mass spectrometry.

Science.gov (United States)

Baker, David R; Kasprzyk-Hordern, Barbara

2011-11-04

Presented is the first comprehensive study of drugs of abuse on suspended particulate matter (SPM) in wastewater. Analysis of SPM is crucial to prevent the under-reporting of the levels of analyte that may be present in wastewater. Analytical methods to date analyse the aqueous part of wastewater samples only, removing SPM through the use of filtration or centrifugation. The development of an analytical method to determine 60 compounds on SPM using a combination of pressurised liquid extraction, solid phase extraction and liquid chromatography coupled with tandem mass spectrometry (PLE-SPE-LC-MS/MS) is reported. The range of compounds monitored included stimulants, opioid and morphine derivatives, benzodiazepines, antidepressants, dissociative anaesthetics, drug precursors, and their metabolites. The method was successfully validated (parameters studied: linearity and range, recovery, accuracy, reproducibility, repeatability, matrix effects, and limits of detection and quantification). The developed methodology was applied to SPM samples collected at three wastewater treatment plants in the UK. The average proportion of analyte on SPM as opposed to in the aqueous phase was 10% with regard to methadone, EDDP, EMDP, BZP, fentanyl, nortramadol, norpropoxyphene, sildenafil and all antidepressants (dosulepin, amitriptyline, nortriptyline, fluoxetine and norfluoxetine). Consequently, the lack of SPM analysis in wastewater sampling protocol could lead to the under-reporting of the measured concentration of some compounds. Copyright © 2011 Elsevier B.V. All rights reserved.

[Determination of deoxynivalenol in grain and its products by solid-phase extraction coupled with high performance liquid chromatography-tandem mass spectrometry].

Science.gov (United States)

Huang, Juan; Chen, Guosong; Zhang, Xiaoyan; Shen, Chongyu; Lü, Chen; Wu, Bin; Liu, Yan; Chen, Huilan; Ding, Tao

2012-11-01

A method was established for the determination of deoxynivalenol (vomitoxin) in grain and its products based on solid-phase extraction coupled with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The sample was firstly extracted by acetonitrile-water (84:16, v/v). The extract was then cleaned-up by an HLB solid phase extraction cartridge. The separation was carried out on a Phenomenex Kinetex C18 column (100 mm x4. 6 mm, 2.6 microm) with a gradient elution using 0.3% per hundred ammonia solution-acetonitrile as mobile phases. The analysis of deoxynivalenol was performed under electrospray negative ionization mode. The limit of detection (LOD, S/N= 3) and the limit of quantification (LOQ, S/N = 10) were 20 microg/kg and 50 microg/kg, respectively. A good linearity (r > 0.99) was achieved for the target compound over the range of 20-1000 pg/L. The recoveries at the three spiked levels (50, 100, 500 microg/kg) in the blank matrices such as flour, barley, soybean, rice, cornmeal, cassava and wheat, were varied from 75.6% to 111.0% with the relative standard deviations no more than 13. 0%. The method is accurate, efficient, sensitive and practical. The cost of pretreatment is obviously reduced by replacing immunoaffinity columns and Mycosep columns with HLB columns which have the same purification effect.

Accurate determination of 3-alkyl-2-methoxypyrazines in wines by gas chromatography quadrupole time-of-flight tandem mass spectrometry following solid-phase extraction and dispersive liquid-liquid microextraction.

Science.gov (United States)

Fontana, Ariel; Rodríguez, Isaac; Cela, Rafael

2017-09-15

A new reliable method for the determination 3-alkyl-2-methoxypyrazines (MPs) in wine samples based on the sequential combination of solid-phase extraction (SPE), dispersive liquid-liquid microextraction (DLLME) and gas chromatography (GC) quadrupole time-of-flight accurate tandem mass spectrometry (QTOF-MS/MS) is presented. Primary extraction of target analytes was carried out by using a reversed-phase Oasis HLB (200mg) SPE cartridge combined with acetonitrile as elution solvent. Afterwards, the SPE extract was submitted to DLLME concentration using 0.06mL carbon tetrachloride (CCl 4 ) as extractant. Under final working conditions, sample concentration factors above 379 times and limits of quantification (LOQs) between 0.3 and 2.1ngL -1 were achieved. Moreover, the overall extraction efficiency of the method was unaffected by the particular characteristics of each wine; thus, accurate results (relative recoveries from 84 to 108% for samples spiked at concentrations from 5 to 25ngL -1 ) were obtained using matrix-matched standards, without using standard additions over every sample. Highly selective chromatographic records were achieved considering a mass window of 5mDa, centered in the quantification product ion corresponding to each compound. Twelve commercial wines, elaborated with grapes from different varieties and geographical origins, were processed with the optimized method. The 2-isobutyl-3-methoxypyrazine (IBMP) was determined at levels above the LOQs of the method in half of the samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Ionic-Liquid-Mediated Extraction and Separation Processes for Bioactive Compounds: Past, Present, and Future Trends.

Science.gov (United States)

Ventura, Sónia P M; E Silva, Francisca A; Quental, Maria V; Mondal, Dibyendu; Freire, Mara G; Coutinho, João A P

2017-05-24

Ionic liquids (ILs) have been proposed as promising media for the extraction and separation of bioactive compounds from the most diverse origins. This critical review offers a compilation on the main results achieved by the use of ionic-liquid-based processes in the extraction and separation/purification of a large range of bioactive compounds (including small organic extractable compounds from biomass, lipids, and other hydrophobic compounds, proteins, amino acids, nucleic acids, and pharmaceuticals). ILs have been studied as solvents, cosolvents, cosurfactants, electrolytes, and adjuvants, as well as used in the creation of IL-supported materials for separation purposes. The IL-based processes hitherto reported, such as IL-based solid-liquid extractions, IL-based liquid-liquid extractions, IL-modified materials, and IL-based crystallization approaches, are here reviewed and compared in terms of extraction and separation performance. The key accomplishments and future challenges to the field are discussed, with particular emphasis on the major lacunas found within the IL community dedicated to separation processes and by suggesting some steps to overcome the current limitations.

Rapid Solid-Liquid Dynamic Extraction (RSLDE): a New Rapid and Greener Method for Extracting Two Steviol Glycosides (Stevioside and Rebaudioside A) from Stevia Leaves.

Science.gov (United States)

Gallo, Monica; Vitulano, Manuela; Andolfi, Anna; DellaGreca, Marina; Conte, Esterina; Ciaravolo, Martina; Naviglio, Daniele

2017-06-01

Stevioside and rebaudioside A are the main diterpene glycosides present in the leaves of the Stevia rebaudiana plant, which is used in the production of foods and low-calorie beverages. The difficulties associated with their extraction and purification are currently a problem for the food processing industries. The objective of this study was to develop an effective and economically viable method to obtain a high-quality product while trying to overcome the disadvantages derived from the conventional transformation processes. For this reason, extractions were carried out using a conventional maceration (CM) and a cyclically pressurized extraction known as rapid solid-liquid dynamic extraction (RSLDE) by the Naviglio extractor (NE). After only 20 min of extraction using the NE, a quantity of rebaudioside A and stevioside equal to 1197.8 and 413.6 mg/L was obtained, respectively, while for the CM, the optimum time was 90 min. From the results, it can be stated that the extraction process by NE and its subsequent purification developed in this study is a simple, economical, environmentally friendly method for producing steviol glycosides. Therefore, this method constitutes a valid alternative to conventional extraction by reducing the extraction time and the consumption of toxic solvents and favouring the use of the extracted metabolites as food additives and/or nutraceuticals. As an added value and of local interest, the experiment was carried out on stevia leaves from the Benevento area (Italy), where a high content of rebaudioside A was observed, which exhibits a sweet taste compared to stevioside, which has a significant bitter aftertaste.

Recent progress of task-specific ionic liquids in chiral resolution and extraction of biological samples and metal ions.

Science.gov (United States)

Wu, Datong; Cai, Pengfei; Zhao, Xiaoyong; Kong, Yong; Pan, Yuanjiang

2018-01-01

Ionic liquids have been functionalized for modern applications. The functional ionic liquids are also called task-specific ionic liquids. Various task-specific ionic liquids with certain groups have been constructed and exploited widely in the field of separation. To take advantage of their properties in separation science, task-specific ionic liquids are generally used in techniques such as liquid-liquid extraction, solid-phase extraction, gas chromatography, high-performance liquid chromatography, and capillary electrophoresis. This review mainly covers original research papers published in the last five years, and we will focus on task-specific ionic liquids as the chiral selectors in chiral resolution and as extractant or sensor for biological samples and metal ion purification. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Solid-phase extraction of chlorophenols in seawater using a magnetic ionic liquid molecularly imprinted polymer with incorporated silicon dioxide as a sorbent.

Science.gov (United States)

Ma, Wanwan; Row, Kyung Ho

2018-07-20

A type of magnetic ionic liquid based molecularly imprinted polymer coated on SiO 2 (Fe 3 O 4 @SiO 2 @IL-MIPs) was prepared with 1-vinyl-3-ethylimidazole ionic liquid as functional monomer, and 1,4-butane-3,3'-bis-1-ethylimidazole ionic liquid as cross linker, 4-Chlorophenol as template was successfully applied as a selective adsorbent for selective extraction of 5 chlorophenols in seawater samples by using the magnetic solid-phase extraction (MSPE) method. 11 types of Fe 3 O 4 @SiO 2 @IL-MIPs were synthesized and investigated for their different compositions of functional monomer (such as [C 2 min][Br], [C 2 min][BF 4 ], [C 2 min][PF 6 ], acrylamide, methacrylic acid and 4-vinyl pyridine) and cross-linker (such as [C 4 min 2 ][Br], [C 4 min 2 ][BF 4 ], [C 4 min 2 ][PF 6 ], divinylbenzene, and ethylene glycol dimethacrylate), respectively. The [C 2 min][BF 4 ] and [C 4 min 2 ][PF 6 ] based Fe 3 O 4 @SiO 2 @IL-MIP with the highest extraction efficiencies was applied to the optimization experiment of MSPE process (including extraction time, adsorbent mass and desorption solvents). Good linearity was obtained with correlation coefficients (R 2 ) over 0.9990 and the relative standard deviations for the intra-day and inter-day determination were less than 3.10% with the extraction recoveries ranged from 85.0% to 98.4%. The results indicated that the proposed Fe 3 O 4 @SiO 2 @IL-MIPs possesses great identification and adsorption properties, and could be used as a good sorbent for selective extraction of CPs in environment waters. Copyright © 2018 Elsevier B.V. All rights reserved.

Preparation and quantification of the total phenolic products in Citrus fruit using solid-phase extraction coupled with high-performance liquid chromatography with diode array and UV detection.

Science.gov (United States)

Zeng, Honglian; Liu, Zhenli; Zhao, Siyu; Shu, Yisong; Song, Zhiqian; Wang, Chun; Dong, Yunzhuo; Ning, Zhangchi; He, Dan; Wang, Menglei; Lu, Cheng; Liu, Yuanyan; Lu, Aiping

2016-10-01

Citrus fruit is an important health-promoting food that is rich in dietary phenolic metabolites. Traditional Chinese medicines, such as Zhishi and Zhiqiao, come from young and immature fruits of Citrus cultivars. The preparation of diversified bioactive phenolic products and establishment of the corresponding quality control methodology are challenging and necessary. In the current study, four types of solid-phase extraction sorbents for the enrichment and clean-up of the phenolic matrix were evaluated. A solid-phase extraction column coated with Strata-X was finally used in the procedure. Twenty phenolic compounds were selected to evaluate the extraction performances of the sorbents using high-performance liquid chromatography analysis. Under the optimized conditions, good linearities were obtained with R 2 more than 0.9996 for all analytes with LODs of 0.04-1.012 μg/g. Intra- and interday relative standard deviation values were less than 3%, and the recovery was equal to or higher than 90.02%. Compared to non-solid-phase extraction process, the content of total phenolic products was elevated 35.55-68.48% with solid-phase extraction. Finally, the developed and validated method was successfully applied to the discrimination of Zhishi samples from different species as well as Zhishi and Zhiqiao samples in different development stages. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Miniaturised pressurised liquid extraction aromatic hydrocarbons from soil and sediment with subsequent large-volume injection-gas chromatography

NARCIS (Netherlands)

Ramos, L.; Vreuls, J.J.; Brinkman, U.A.T.

2000-01-01

Analyte extraction is the main limitation when developing at-line, or on-line, procedures for the preparation of (semi)solid environmental samples. Pressurised liquid extraction (PLE) is an analyte- and matrix-independent technique which provides cleaner extracts than the time-consuming classical

Liquid-liquid extraction of plutonium(IV) in monoamide - ammonium ionic liquid mixture

International Nuclear Information System (INIS)

Rout, Alok; Venkatesan, K.A.; Antony, M.P.

2016-01-01

Room temperature ionic liquid (RTIL) can be regarded as a sustainable alternative to the conventional molecular diluent, n-dodecane (n-DD), in solvent extraction process. Replacement of volatile organic solvents by RTILs in solvent extraction could lead to inherently safer processes. As far as the cation is concerned, most of the studies reported in literature are focused on imidazolium-based ionic liquids. In contrast to imiadazolium ionic liquids, quarternary ammonium ionic liquids like trioctylmethylammonium chloride (Aliquat 336), trioctylmethylammonium nitrate etc., do not exhibit any cation exchange with the metal ions from aqueous phase during extraction. However, there is no report available in literature that emphasizes the application of trioctylmethylammonium bis(trifluoromethane-sulfonyl)imide ((N_1_8_8_8)(NTf_2)) ionic liquid, for the extraction of Pu(IV). In this paper, we report the advantages of using the ionic liquid, trioctylmethylammonium bis(trifluoromethanesulfonyl)imide ((N_1_8_8_8)(NTf_2)), as diluent, for the extraction of plutonium(IV) in DHOA/(N_1_8_8_8)(NTf_2)

Development of a magnetic solid-phase extraction coupled with high-performance liquid chromatography method for the analysis of polyaromatic hydrocarbons.

Science.gov (United States)

Ma, Yan; Xie, Jiawen; Jin, Jing; Wang, Wei; Yao, Zhijian; Zhou, Qing; Li, Aimin; Liang, Ying

2015-07-01

A novel magnetic solid phase extraction coupled with high-performance liquid chromatography method was established to analyze polyaromatic hydrocarbons in environmental water samples. The extraction conditions, including the amount of extraction agent, extraction time, pH and the surface structure of the magnetic extraction agent, were optimized. The results showed that the amount of extraction agent and extraction time significantly influenced the extraction performance. The increase in the specific surface area, the enlargement of pore size, and the reduction of particle size could enhance the extraction performance of the magnetic microsphere. The optimized magnetic extraction agent possessed a high surface area of 1311 m(2) /g, a large pore size of 6-9 nm, and a small particle size of 6-9 μm. The limit of detection for phenanthrene and benzo[g,h,i]perylene in the developed analysis method was 3.2 and 10.5 ng/L, respectively. When applied to river water samples, the spiked recovery of phenanthrene and benzo[g,h,i]perylene ranged from 89.5-98.6% and 82.9-89.1%, respectively. Phenanthrene was detected over a concentration range of 89-117 ng/L in three water samples withdrawn from the midstream of the Huai River, and benzo[g,h,i]perylene was below the detection limit. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Production of fungal antibiotics using polymeric solid supports in solid-state and liquid fermentation.

Science.gov (United States)

Bigelis, Ramunas; He, Haiyin; Yang, Hui Y; Chang, Li-Ping; Greenstein, Michael

2006-10-01

The use of inert absorbent polymeric supports for cellular attachment in solid-state fungal fermentation influenced growth, morphology, and production of bioactive secondary metabolites. Two filamentous fungi exemplified the utility of this approach to facilitate the discovery of new antimicrobial compounds. Cylindrocarpon sp. LL-Cyan426 produced pyrrocidines A and B and Acremonium sp. LL-Cyan416 produced acremonidins A-E when grown on agar bearing moist polyester-cellulose paper and generated distinctly different metabolite profiles than the conventional shaken or stationary liquid fermentations. Differences were also apparent when tenfold concentrated methanol extracts from these fermentations were tested against antibiotic-susceptible and antibiotic-resistant Gram-positive bacteria, and zones of inhibition were compared. Shaken broth cultures of Acremonium sp. or Cylindrocarpon sp. showed complex HPLC patterns, lower levels of target compounds, and high levels of unwanted compounds and medium components, while agar/solid support cultures showed significantly increased yields of pyrrocidines A and B and acremonidins A-E, respectively. This method, mixed-phase fermentation (fermentation with an inert solid support bearing liquid medium), exploited the increase in surface area available for fungal growth on the supports and the tendency of some microorganisms to adhere to solid surfaces, possibly mimicking their natural growth habits. The production of dimeric anthraquinones by Penicillium sp. LL-WF159 was investigated in liquid fermentation using various inert polymeric immobilization supports composed of polypropylene, polypropylene cellulose, polyester-cellulose, or polyurethane. This culture produced rugulosin, skyrin, flavomannin, and a new bisanthracene, WF159-A, after fermentation in the presence and absence of polymeric supports for mycelial attachment. The physical nature of the different support systems influenced culture morphology and relative

Preparation of ionic liquid modified magnetic metal-organic frameworks composites for the solid-phase extraction of α-chymotrypsin.

Science.gov (United States)

Wei, Xiaoxiao; Wang, Yuzhi; Chen, Jing; Xu, Panli; Zhou, Yigang

2018-05-15

A novel magnetic solid-phase extraction (MSPE) method based on 1-hexyl-3-methyl imidazolium chloride ionic liquid (IL) modified magnetic Fe 3 O 4 nanoparticles, hydroxylated multiwall carbon nanotubes (MWCNTs-OH) and zeolitic imidazolate frameworks (ZIFs) nanocomposites (Fe 3 O 4 -MWCNTs-OH@ZIF-67@IL) were proposed and applied to extract α-chymotrypsin. The magnetic materials were synthesized successfully and characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), thermal gravimetric analysis (TGA), fourier transform infrared spectrometry (FT-IR), vibrating sample magnetometer (VSM) and zeta potentials. Subsequently, the UV-vis spectrophotometer at about 280 nm was utilized to quantitatively analyze the α-chymotrypsin concentration in the supernatant. Furthermore, single factor experiments revealed that the extraction capacity was influenced by initial α-chymotrypsin concentration, ionic strength, extraction time, extraction temperature and pH value. The extraction capacity could reach up to about 635 mg g -1 under the optimized conditions, absolutely higher than that of extraction for Ovalbumin (OVA), Bovine serum albumin (BSA) and Bovine hemoglobin (BHb). In addition, the regeneration studies showed Fe 3 O 4 -MWCNTs-OH@ZIF-67@IL particles could be reused several times and kept a high extraction capacity. Besides, the study of enzymatic activity also indicated that the activity of the extracted α-chymotrypsin was well maintained 93% of initial activity. What's more, the proposed method was successfully applied to extract α-chymotrypsin in porcine pancreas crude extract with satisfactory results. All of above conclusions highlight the great potential of the proposed Fe 3 O 4 -MWCNTs-OH@ZIF-67@IL-MSPE method in the analysis of biomolecules. Copyright © 2018 Elsevier B.V. All rights reserved.

Analyses of Indole Compounds in Sugar Cane (Saccharum officinarum L. Juice by High Performance Liquid Chromatography and Liquid Chromatography-Mass Spectrometry after Solid-Phase Extraction

Directory of Open Access Journals (Sweden)

Jean Wan Hong Yong

2017-03-01

Full Text Available Simultaneous quantitative analysis of 10 indole compounds, including indole-3-acetic acid (IAA, one of the most important naturally occurring auxins and some of its metabolites, by high performance liquid chromatography (HPLC and liquid chromatography-mass spectrometry (LC-MS after solid-phase extraction (SPE was reported for the first time. The analysis was carried out using a reverse phase HPLC gradient elution, with an aqueous mobile phase (containing 0.1% formic acid modified by methanol. Furthermore, a novel SPE procedure was developed for the pre-concentration and purification of indole compounds using C18 SPE cartridges. The combination of SPE, HPLC, and LC-MS was applied to screen for the indole compounds present in sugar cane (Saccharum officinarum L. juice, a refreshing beverage with various health benefits. Finally, four indole compounds were successfully detected and quantified in sugar cane juice by HPLC, which were further unequivocally confirmed by LC-MS/MS experiments operating in the multiple reaction monitoring (MRM mode.

SISAK liquid-liquid extraction experiments with preseparated 257Rf

International Nuclear Information System (INIS)

Omtvedt, Jon Petter; Alstad, J.; Breivik, H.; Dyve, J.E.; Eberhardt, K.; Folden III, C.M.; Ginter, T.; Gregorich, K.E.; Hult, E.A.; Johansson, M.; Kirbach, U.W.; Lee, D.M.; Mendel, M.; Nahler, A.; Ninov, V.; Omtvedt, L.A.; Patin, J.B.; Skarnemark, G.; Stavsetra, L.; Sudowe, R.; Wiehl, N.; Wierczinski, B.; Wilk, P.A.; Zielinski, P.M.; Kratz, J.V.; Trautmann, N.; Nitsche, H.; Hoffman, D.C.

2002-01-01

The SISAK liquid-liquid extraction system was used to extract 4.0-s 257Rf. The 257Rf was produced in the reaction 208Pb(50Ti, 1n)257Rf with 237-MeV beam energy on target, separated in the Berkeley Gas-filled Separator (BGS) and transferred to a gas jet using the Recoil Transfer Chamber (RTC). The activity delivered by the gas jet was dissolved in 6-M HNO3 and Rf was extracted into 0.25-M dibutyl-phosphoric acid in toluene. This was the first time a transactinide, i.e., an element with Z >= 104, was extracted and unequivocally identified by the SISAK system. Thus, this pilot experiment demonstrates that the fast liquid-liquid extraction system SISAK, in combination with liquidscintillation detectors, can be used for investigating the chemical properties of the transactinides. The extraction result is in accordance with the behaviour shown by the Rf group IV homologues Zr and Hf

Selective ionic liquid ferrofluid based dispersive-solid phase extraction for simultaneous preconcentration/separation of lead and cadmium in milk and biological samples.

Science.gov (United States)

Fasih Ramandi, Negin; Shemirani, Farzaneh

2015-01-01

For the first time, a selective ionic liquid ferrofluid has been used in dispersive solid phase extraction (IL-FF-D-SPE) for simultaneous preconcentration and separation of lead and cadmium in milk and biological samples combined with flame atomic absorption spectrometry. To improve the selectivity of the ionic liquid ferrofluid, the surface of TiO2 nanoparticles with a magnetic core as sorbent was modified by loading 1-(2-pyridylazo)-2-naphtol. Due to the rapid injection of an appropriate amount of ionic liquid ferrofluid into the aqueous sample by a syringe, extraction can be achieved within a few seconds. In addition, based on the attraction of the ionic liquid ferrofluid to a magnet, no centrifugation step is needed for phase separation. The experimental parameters of IL-FF-D-SPE were optimized using a Box-Behnken design (BBD) after a Plackett-Burman screening design. Under the optimum conditions, the relative standard deviations of 2.2% and 2.4% were obtained for lead and cadmium, respectively (n=7). The limit of detections were 1.21 µg L(-1) for Pb(II) and 0.21 µg L(-1) for Cd(II). The preconcentration factors were 250 for lead and 200 for cadmium and the maximum adsorption capacities of the sorbent were 11.18 and 9.34 mg g(-1) for lead and cadmium, respectively. Copyright © 2014 Elsevier B.V. All rights reserved.

The optimization of extraction of antioxidants from apple pomace by pressurized liquids.

Science.gov (United States)

Wijngaard, Hilde; Brunton, Nigel

2009-11-25

Pressurized liquid extraction (PLE) is a green extraction technique that can enhance extraction rates of bioactive compounds. PLE was used to extract antioxidants and polyphenols from industrially generated apple pomace at two different temperature ranges: 160 to 193 degrees C and 75 to 125 degrees C. Antioxidant activity (DPPH radical scavenging test), total phenol content and three individual polyphenol groups were determined. Response surface methodology was used to optimize the five response values. Maximum antioxidant activity was obtained at a temperature of 200 degrees C, but unwanted compounds such as hydroxymethylfurfural were formed. Therefore a lower temperature range between 75 and 125 degrees C is recommended. Using this temperature range, a maximum antioxidant activity was determined at 60% ethanol and 102 degrees C. By using PLE the antioxidant activity was increased 2.4 times in comparison to traditional solid-liquid extraction, and the technique may be a promising alternative to conventional techniques for extracting antioxidants.

SISAK liquid-liquid extraction experiments with preseparated {sup 257}Rf

Energy Technology Data Exchange (ETDEWEB)

Omtvedt, Jon Petter; Alstad, J.; Breivik, H. [University of Oslo, Department of Chemistry, Oslo (NO)] (and others)

2002-06-01

The SISAK liquid-liquid extraction system was used to extract 4.0-s {sup 257}Rf. The {sup 257}Rf was produced in the reaction {sup 208}Pb({sup 50}Ti, 1n){sup 257}Rf with 237-MeV beam energy on target, separated in the Berkeley Gas-filled Separator (BGS) and transferred to a gas jet using the Recoil Transfer Chamber (RTC). The activity delivered by the gas jet was dissolved in 6-M HNO{sub 3} and Rf was extracted into 0.25-M dibutyl-phosphoric acid in toluene. This was the first time a transactinide, i.e., an element with Z{>=}104, was extracted and unequivocally identified by the SISAK system. Thus, this pilot experiment demonstrates that the fast liquid-liquid extraction system SISAK, in combination with liquid-scintillation detectors, can be used for investigating the chemical properties of the transactinides. The extraction result is in accordance with the behaviour shown by the Rf group IV homologues Zr and Hf. (author)

Simultaneous determination of atorvastatin and valsartan in human plasma by solid-based disperser liquid-liquid microextraction followed by high-performance liquid chromatography-diode array detection.

Science.gov (United States)

Farajzadeh, Mir Ali; Khorram, Parisa; Pazhohan, Azar

2016-04-01

A simple, sensitive, and efficient method has been developed for simultaneous estimation of valsartan and atorvastatin in human plasma by combination of solid-based dispersive liquid-liquid microextraction and high performance liquid chromatography-diode array detection. In the proposed method, 1,2-dibromoethane (extraction solvent) is added on a sugar cube (as a solid disperser) and it is introduced into plasma sample containing the analytes. After manual shaking and centrifugation, the resultant sedimented phase is subjected to back extraction into a small volume of sodium hydrogen carbonate solution using air-assisted liquid-liquid microextraction. Then the cloudy solution is centrifuged and the obtained aqueous phase is transferred into a microtube and analyzed by the separation system. Under the optimal conditions, extraction recoveries are obtained in the range of 81-90%. Calibration curves plotted in drug-free plasma sample are linear in the ranges of 5-5000μgL(-1) for valsartan and 10-5000μgL(-1) for atorvastatin with the coefficients of determination higher than 0.997. Limits of detection and quantification of the studied analytes in plasma sample are 0.30-2.6 and 1.0-8.2μgL(-1), respectively. Intra-day (n=6) and inter-days (n=4) precisions of the method are satisfactory with relative standard deviations less than 7.4% (at three levels of 10, 500, and 2000μgL(-1), each analyte). These data suggest that the method can be successfully applied to determine trace amounts of valsartan and atorvastatin in human plasma samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Cyclodextrin-based miniaturized solid phase extraction for biopesticides analysis in water and vegetable juices samples analyzed by ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry.

Science.gov (United States)

Peng, Li-Qing; Ye, Li-Hong; Cao, Jun; Chang, Yan-Xu; Li, Qin; An, Mingrui; Tan, Zhijing; Xu, Jing-Jing

2017-07-01

A cyclodextrin-based miniaturized solid-phase extraction was developed to extract biopesticides from water and vegetable juices. The analytes were detected by ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry. In the solid-phase extraction (SPE) procedure, the liquid sample solution is passed through a packed column filled with 40mg of HP-β-CD, and then the target analytes are absorbed and finally eluted with methanol-acetic acid (90:10, v/v) into a collection tube. The limits of quantification ranged from 3.73 to 16.51ng/mL for a water matrix, from 2.62 to 13.23ng/mL for an orange juice matrix and from 1.76 to 10.35ng/mL for a tomato juice matrix, respectively. The average recovery values were in the range of 88.3-95.9% for the spiked samples. The established methodology was successfully applied to analyze sanguinarine, berberine, rotenone and osthole in water, orange juice and tomato juice. Copyright © 2017 Elsevier Ltd. All rights reserved.

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.

CATION-EXCHANGE SOLID-PHASE AND LIQUID-LIQUID ...

African Journals Online (AJOL)

B. S. Chandravanshi

An existing liquid-liquid extraction (LLE) method was improved in terms of ... clean-up of the alkaloids from khat leaves, prior to HPLC-DAD detection. Despite .... The limits of detection (LOD) and quantification (LOQ) were calculated using the.

Liquid-Liquid Extraction in Systems Containing Butanol and Ionic Liquids – A Review

OpenAIRE

Kubiczek Artur; Kamiński Władysław

2017-01-01

Room-temperature ionic liquids (RTILs) are a moderately new class of liquid substances that are characterized by a great variety of possible anion-cation combinations giving each of them different properties. For this reason, they have been termed as designer solvents and, as such, they are particularly promising for liquid-liquid extraction, which has been quite intensely studied over the last decade. This paper concentrates on the recent liquid-liquid extraction studies involving ionic liqu...

Solid on liquid deposition, a review of technological solutions

OpenAIRE

Homsy, Alexandra; Laux, Edith; Jeandupeux, Laure; Charmet, Jérôme; Bitterli, Roland; Botta, Chiara; Rebetez, Yves; Banakh, Oksana; Keppner, Herbert

2015-01-01

Solid-on-liquid deposition (SOLID) techniques are of great interest to the MEMS and NEMS (Micro- and Nano Electro Mechanical Systems) community because of potential applications in biomedical engineering, on-chip liquid trapping, tunable micro-lenses, and replacements of gate oxides. However, depositing solids on liquid with subsequent hermetic sealing is difficult because liquids tend to have a lower density than solids. Furthermore, current systems seen in nature lack thermal, mechanical or...

Methods of Analysis by the U.S. Geological Survey Organic Geochemistry Research Group--Determination of Triazine and Phenylurea Herbicides and Their Degradation Products in Water Using Solid-Phase Extraction and Liquid Chromatography/Mass Spectrometry

National Research Council Canada - National Science Library

Lee, E. A; Strahan, A. P; Thurman, E. M

2002-01-01

An analytical method for the determination of 7 triazine and phenylurea herbicides and 12 of their degradation products in natural water samples using solid-phase extraction and liquid chromatography...

Multiplexed Colorimetric Solid-Phase Extraction

Science.gov (United States)

Gazda, Daniel B.; Fritz, James S.; Porter, Marc D.

2009-01-01

Multiplexed colorimetric solid-phase extraction (MC-SPE) is an extension of colorimetric solid-phase extraction (C-SPE) an analytical platform that combines colorimetric reagents, solid phase extraction, and diffuse reflectance spectroscopy to quantify trace analytes in water. In CSPE, analytes are extracted and complexed on the surface of an extraction membrane impregnated with a colorimetric reagent. The analytes are then quantified directly on the membrane surface using a handheld diffuse reflectance spectrophotometer. Importantly, the use of solid-phase extraction membranes as the matrix for impregnation of the colorimetric reagents creates a concentration factor that enables the detection of low concentrations of analytes in small sample volumes. In extending C-SPE to a multiplexed format, a filter holder that incorporates discrete analysis channels and a jig that facilitates the concurrent operation of multiple sample syringes have been designed, enabling the simultaneous determination of multiple analytes. Separate, single analyte membranes, placed in a readout cartridge create unique, analyte-specific addresses at the exit of each channel. Following sample exposure, the diffuse reflectance spectrum of each address is collected serially and the Kubelka-Munk function is used to quantify each water quality parameter via calibration curves. In a demonstration, MC-SPE was used to measure the pH of a sample and quantitate Ag(I) and Ni(II).

The separation of solid and liquid components of mixtures

International Nuclear Information System (INIS)

Hunter, W.M.

1980-01-01

An improved method of separating solid and liquid components of mixtures is described which is particularly suited for use in automated radioimmunoassay systems in the analysis of bound and free fractions. A second liquid, having a density intermediate between those of the solid and liquid components, is delivered to the solid/ liquid mixture to form a discrete layer below the mixture and the solid separates into this lower liquid layer assisted by centrifugal force. The second liquid of intermediate density is an aqueous solution of a highly hydrophilic and electrically non-polar solute, such as an aqueous sucrose solution. Further liquids of intermediate density and progressively higher density may be delivered to form further discrete layers below the initial layer of the second dense liquid. After separation of the solid and liquid components of the mixture, the supernatant liquid component of the original mixture is removed in a controlled and non-turbulent manner. The method is illustrated in radioimmunoassays for platelet β-thromboglobulin and human follicle stimulating hormone. (U.K.)

Determination of bisphenol-type endocrine disrupting compounds in food-contact recycled-paper materials by focused ultrasonic solid-liquid extraction and ultra performance liquid chromatography-high resolution mass spectrometry.

Science.gov (United States)

Pérez-Palacios, David; Fernández-Recio, Miguel Ángel; Moreta, Cristina; Tena, María Teresa

2012-09-15

Focused ultrasonic solid-liquid extraction (FUSLE) and reverse-phase ultra performance liquid chromatography (UPLC) coupled to a quadrupole-time of flight mass spectrometer (Q-TOF-MS) was applied to the determination of bisphenol-type endocrine disrupting compounds (EDCs) in food-contact recycled-paper materials. Recycled paper is a potential source of EDCs. Bisphenol A (BPA), bisphenol F (BPF) and their derivatives bisphenol A diglycidyl ether (BADGE) and bisphenol F diglycidyl ether (BFDGE) are used for the production of epoxy resins employed in the formulation of printing inks. The FUSLE of bisphenol-type EDCs from packaging is reported for the first time. First, different extraction solvents were studied and methanol was selected. Then, the main FUSLE factors affecting the extraction efficiency (solvent volume, extraction time and ultrasonic irradiation power) were studied by means of a central composite design. The FUSLE conditions selected for further experiments were 20 ml of methanol at ultrasonic amplitude of 100% for 5s. Finally, the number of extraction cycles necessary for complete extraction was established in two. The analysis of the FUSLE extracts was carried out by UPLC-Q-TOF-MS with electrospray ionization and the determination of the four analytes took place in only 4 min. The FUSLE and UPLC-ESI-QTOF-MS method was validated and applied to the analysis of different food-contact recycled-paper-based materials and packaging. The proposed method provided recoveries from 72% to 97%, repeatability and intermediate precision under 9% and 14%, respectively, and detection limits of 0.33, 0.16, 0.65 and 0.40 μg/g for BPA, BPF, BADGE and BFDGE, respectively. The analysis of paper and cardboard samples confirmed the presence of EDCs in these packaging. Copyright © 2012 Elsevier B.V. All rights reserved.

Positronium quenching in liquid and solid octanol and benzene

DEFF Research Database (Denmark)

Shantarovich, V.P.; Mogensen, O.E.; Goldanskii, V.I.

1970-01-01

The lifetimes of orthopositronium in several solutions in liquid and solid octanol and benzene have been measured. The Ps-quenching constant was found to be two to thirty times higher in the solid than in the liquid phase.......The lifetimes of orthopositronium in several solutions in liquid and solid octanol and benzene have been measured. The Ps-quenching constant was found to be two to thirty times higher in the solid than in the liquid phase....

Solid - solid and solid - liquid phase transitions of iron and iron alloys under laser shock compression

Science.gov (United States)

Harmand, M.; Krygier, A.; Appel, K.; Galtier, E.; Hartley, N.; Konopkova, Z.; Lee, H. J.; McBride, E. E.; Miyanishi, K.; Nagler, B.; Nemausat, R.; Vinci, T.; Zhu, D.; Ozaki, N.; Fiquet, G.

2017-12-01

An accurate knowledge of the properties of iron and iron alloys at high pressures and temperatures is crucial for understanding and modelling planetary interiors. While Earth-size and Super-Earth Exoplanets are being discovered in increasingly large numbers, access to detailed information on liquid properties, melting curves and even solid phases of iron and iron at the pressures and temperatures of their interiors is still strongly limited. In this context, XFEL sources coupled with high-energy lasers afford unique opportunities to measure microscopic structural properties at far extreme conditions. Also the achievable time resolution allows the shock history and phase transition mechanisms to be followed during laser compression, improving our understanding of the high pressure and high strain experiments. Here we present recent studies devoted to investigate the solid-solid and solid-liquid transition in laser-shocked iron and iron alloys (Fe-Si, Fe-C and Fe-O alloys) using X-ray diffraction and X-ray diffuse scattering. Experiment were performed at the MEC end-station of the LCLS facility at SLAC (USA). Detection of the diffuse scattering allowed the identification of the first liquid peak position along the Hugoniot, up to 4 Mbar. The time resolution shows ultrafast (between several tens and several hundreds of picoseconds) solid-solid and solid-liquid phase transitions. Future developments at XFEL facilities will enable detailed studies of the solid and liquid structures of iron and iron alloys as well as out-of-Hugoniot studies.

Kinetic of liquid-liquid extraction for uranyl nitrate and actinides (III) and lanthanides (III) nitrates by amide extractants

International Nuclear Information System (INIS)

Toulemonde, V.; CEA Centre d'Etudes de la Vallee du Rhone, 30 -Marcoule

1995-01-01

The kinetics of liquid-liquid extraction by amide extractants have been investigated for uranyl nitrate (monoamide extractants), actinides (III) and lanthanides (III) nitrates (diamide extractants). The transfer of the metallic species from the aqueous phase to the organic phase was studied using two experimental devices: ARMOLLEX (Argonne Modified Lewis cell for Liquid Liquid Extraction) and RSC (Rotating Stabilized Cell). The main conclusions are: for the extraction of uranyl nitrate by DEHDMBA monoamide, the rate-controlling step is the complexation of the species at the interface of the two liquids. Thus, an absorption-desorption (according to Langmuir theory) reaction mechanism was proposed; for the extraction of actinides (III) and lanthanides (III) nitrates in nitric acid media by DMDBTDMA diamide, the kinetic is also limited by interfacial reactions. The behavior of Americium and Europium is very similar as fare as their reaction kinetics are concerned. (author)

Triple aldose reductase/α-glucosidase/radical scavenging high-resolution profiling combined with high-performance liquid chromatography – high-resolution mass spectrometry – solid-phase extraction – nuclear magnetic resonance spectroscopy for identification of antidiabetic constituents in crude, extract of Radix Scutellariae

DEFF Research Database (Denmark)

Tahtah, Yousof; Kongstad, Kenneth Thermann; Wubshet, Sileshi Gizachew

2015-01-01

high-performance liquid chromatography – high-resolution mass spectrometry – solid-phase extraction – nuclear magnetic resonance spectroscopy. The only α-glucosidase inhibitor was baicalein, whereas main aldose reductase inhibitors in the crude extract were baicalein and skullcapflavone II, and main....../α-glucosidase/radical scavenging high-resolution inhibition profile - allowing proof of concept with Radix Scutellariae crude extract as a polypharmacological herbal drug. The triple bioactivity high-resolution profiles were used to pinpoint bioactive compounds, and subsequent structure elucidation was performed with hyphenated...

A review of solid-fluid selection options for optical-based measurements in single-phase liquid, two-phase liquid-liquid and multiphase solid-liquid flows

Science.gov (United States)

Wright, Stuart F.; Zadrazil, Ivan; Markides, Christos N.

2017-09-01

Experimental techniques based on optical measurement principles have experienced significant growth in recent decades. They are able to provide detailed information with high-spatiotemporal resolution on important scalar (e.g., temperature, concentration, and phase) and vector (e.g., velocity) fields in single-phase or multiphase flows, as well as interfacial characteristics in the latter, which has been instrumental to step-changes in our fundamental understanding of these flows, and the development and validation of advanced models with ever-improving predictive accuracy and reliability. Relevant techniques rely upon well-established optical methods such as direct photography, laser-induced fluorescence, laser Doppler velocimetry/phase Doppler anemometry, particle image/tracking velocimetry, and variants thereof. The accuracy of the resulting data depends on numerous factors including, importantly, the refractive indices of the solids and liquids used. The best results are obtained when the observational materials have closely matched refractive indices, including test-section walls, liquid phases, and any suspended particles. This paper reviews solid-liquid and solid-liquid-liquid refractive-index-matched systems employed in different fields, e.g., multiphase flows, turbomachinery, bio-fluid flows, with an emphasis on liquid-liquid systems. The refractive indices of various aqueous and organic phases found in the literature span the range 1.330-1.620 and 1.251-1.637, respectively, allowing the identification of appropriate combinations to match selected transparent or translucent plastics/polymers, glasses, or custom materials in single-phase liquid or multiphase liquid-liquid flow systems. In addition, the refractive indices of fluids can be further tuned with the use of additives, which also allows for the matching of important flow similarity parameters such as density and viscosity.

Effect of solid-meal caloric content on gastric emptying kinetics of solids and liquids.

Science.gov (United States)

Urbain, J L; Siegel, J A; Mortelmans, L; van Cutsem, E; van den Maegdenbergh, V; de Roo, M

1989-08-01

In this study, we have evaluated the effect of the caloric content of a physiological test meal on the gastric emptying kinetics of solids and liquids. 22 healthy male volunteers were studied in two groups matched for age. After an overnight fast, each volunteer underwent the same test procedure; in the first group (G I), 10 volunteers received a meal consisting of bread, 111In-DTPA water and 1 scrambled egg labeled with 99mTc-labelled sulphur colloid; in the second group (G II) 12 volunteers were given the same meal but with 2 labeled eggs in order to increase the caloric content of the solid phase meal. Simultaneous anterior and posterior images were recorded using a dual-headed gamma camera. Solid and liquid geometric mean data were analyzed to determine the lag phase, the emptying rate and the half-emptying time for both solids and liquids. Solid and liquid gastric half-emptying times were significantly prolonged in G II compared to G I volunteers. For the solid phased, the delay was accounted for by a longer lag phase and a decrease in the equilibrium emptying rate. The emptying rate of the liquid phase was significantly decreased in G II compared to G I. Within each group, no statistically significant difference was observed between solid and liquid emptying rates. We conclude that the caloric content of the solid portion of a meal not only alters the emptying of the solid phase but also affects the emptying of the liquid component of the meal.

Effect of solid-meal caloric content on gastric emptying kinetics of solids and liquids

International Nuclear Information System (INIS)

Urbain, J.L.; Mortelmans, L.; Cutsem, E. van; Maegdenbergh, V. van den; Roo, M. de

1989-01-01

In this study, we have evaluated the effect of the caloric content of a physiological test meal on the gastric emptying kinetics of solids and liquids. 22 healthy male volunteers were studied in two groups matched for age. After an overnight fast, each volunteer underwent the same test procedure; in the first group (G I), 10 volunteers received a meal consisting of bread, 111 In-DTPA water and 1 scrambled egg labeled with 99m Tc-labelled sulphur colloid; in the second group (G II) 12 volunteers were given the same meal but with 2 labeled eggs in order to increase the caloric content of the solid phase meal. Simultaneous anterior and posterior images were recorded using a dual-headed gamma camera. Solid and liquid geometric mean data were analyzed to determine the lag phase, the emptying rate and the half-emptying time for both solids and liquids. Solid and liquid gastric half-emptying times were significantly prolonged in G II compared to G I volunteers. For the solid phased, the delay was accounted for by a longer lag phase and a decrease in the equilibrium emptying rate. The emptying rate of the liquid phase was significantly decreased in G II compared to G I. Within each group, no statistically significant difference was observed between solid and liquid emptying rates. We conclude that the caloric content of the solid portion of a meal not only alters the emptying of the solid phase but also affects the emptying of the liquid component of the meal. (orig.) [de

The Influence of Extractant TOA, Stirring Time on the Extraction ProcessLiquid-liquid, and Liquid Membrane on the Liquid Wastes Containing Cd

International Nuclear Information System (INIS)

Prayitno; Djoko-Sardjono; Nurimaniwati; Adhe-Helmayani

2000-01-01

The influence of extractant and stirring time on the reduction componentcadmium on liquid wastes has been investigated. The method of experimentalused the extraction with liquid membrane emulsion. The parameters to beinvestigated were extractant amount tri-n octylamine (TOA), duration ofstirring time. In this investigated, extractant amount was varied from 5 to25 % (v/v) TOA, duration of stirring time varied from 5 to minutes. Theresult of experimental can be concluded that the best condition obtained forreducing cadmium component was on extractant amount 20 % (v/v) TOA, stirringtime 25 minutes. The best condition for reducing the cadmium component wasefficiency factor 98.35%. (author)

Plate performance in liquid-liquid extraction

International Nuclear Information System (INIS)

Wadkins, R.P.

1984-01-01

The relative effectiveness of perforated, nozzle, and burred plates from a capacity and extraction standpoint were studied in a pulsed liquid-liquid extraction system. The experiments were conducted in a 3.8 x 10 -2 m diameter column using a mixture of aluminum nitrate, nitric acid, and uranyl nitrate as the aqueous phase, and tributyl phosphate dissolved in AMSCO 125-90 W as the organic phase. The uranium was extracted from the aqueous phase to the organic phase. A standard cartridge was made for each type of plate and consisted of an assembly of plates spaced 5.08 x 10 -2 m apart. Each plate had 3.2 x 10 -3 m holes spaced on 6.1 x 10 -3 -m centers, and contained 23% free area. 16 references, 4 figures, 1 table

Effervescence-assisted dispersive solid-phase extraction using ionic-liquid-modified magnetic β-cyclodextrin/attapulgite coupled with high-performance liquid chromatography for fungicide detection in honey and juice.

Science.gov (United States)

Wu, Xiaoling; Yang, Miyi; Zeng, Haozhe; Xi, Xuefei; Zhang, Sanbing; Lu, Runhua; Gao, Haixiang; Zhou, Wenfeng

2016-11-01

In this study, a simple effervescence-assisted dispersive solid-phase extraction method was developed to detect fungicides in honey and juice. Most significantly, an innovative ionic-liquid-modified magnetic β-cyclodextrin/attapulgite sorbent was used because its large specific surface area enhanced the extraction capacity and also led to facile separation. A one-factor-at-a-time approach and orthogonal design were employed to optimize the experimental parameters. Under the optimized conditions, the entire extraction procedure was completed within 3 min. In addition, the calibration curves exhibited good linearity, and high enrichment factors were achieved for pure water and honey samples. For the honey samples, the extraction efficiencies for the target fungicides ranged from 77.0 to 94.3% with relative standard deviations of 2.3-5.44%. The detection and quantitation limits were in the ranges of 0.07-0.38 and 0.23-1.27 μg/L, respectively. Finally, the developed technique was successfully applied to real samples, and satisfactory results were achieved. This analytical technique is cost-effective, environmentally friendly, and time-saving. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Application of micro-solid-phase extraction for the on-site extraction of heterocyclic aromatic amines in seawater.

Science.gov (United States)

Basheer, Chanbasha

2018-04-01

An efficient on-site extraction technique to determine carcinogenic heterocyclic aromatic amines in seawater has been reported. A micro-solid-phase extraction device placed inside a portable battery-operated pump was used for the on-site extraction of seawater samples. Before on-site applications, parameters that influence the extraction efficiency (extraction time, type of sorbent materials, suitable desorption solvent, desorption time, and sample volume) were investigated and optimized in the laboratory. The developed method was then used for the on-site sampling of heterocyclic aromatic amines determination in seawater samples close to distillation plant. Once the on-site extraction completed, the small extraction device with the analytes was brought back to the laboratory for analysis using high-performance liquid chromatography with fluorescence detection. Based on the optimized conditions, the calibration curves were linear over the concentration range of 0.05-20 μg/L with correlation coefficients up to 0.996. The limits of detection were 0.004-0.026 μg/L, and the reproducibility values were between 1.3 and 7.5%. To evaluate the extraction efficiency, a comparison was made with conventional solid-phase extraction and it was applied to various fortified real seawater samples. The average relative recoveries obtained from the spiked seawater samples varied in the range 79.9-95.2%. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Approaches for on-line coupling of extraction and chromatography

Energy Technology Data Exchange (ETDEWEB)

Hyoetylaeinen, Tuulia; Riekkola, Marja-Liisa [Laboratory of Analytical Chemistry, Department of Chemistry, University of Helsinki, P.O. Box 55, 00014, Helsinki (Finland)

2004-04-01

This review provides an overview of the approaches available in order to perform on-line coupling of various extraction techniques with liquid and gas chromatography, for the analysis of semivolatile and nonvolatile analytes in liquid and solid samples. The main focus is on the instrumental set-up of these techniques. Selected real applications are described by way of illustration. The extraction methods suitable for on-line coupling covered in this review are: liquid-liquid extraction, solid-phase extraction, membrane-based techniques, pressurised liquid extraction, supercritical fluid extraction, and microwave- and sonication-assisted extractions. The following systems are not covered in this review: on-line coupled solid-phase extraction-liquid chromatography, purge-and-trap-GC, and membrane extraction with a sorbent interface-GC. (orig.)

Determination of organophosphorus pesticides using molecularly imprinted polymer solid phase extraction

International Nuclear Information System (INIS)

Mohd Marsin Sanagi; Syairah Salleh; Wan Aini Wan Ibrahim

2011-01-01

Molecularly imprinted polymer solid phase extraction (MIP-SPE) method has been developed for the determination of organophosphorus pesticides (OPPs) in water samples. The MIP was prepared by thermo-polymerization method using methacrylic acid (MAA) as functional monomer, ethylene glycol dimethacrylate (EGDMA) as crosslinker, acetonitrile as porogenic solvent and quinalphos as the template molecule. The three OPPs (diazinon, quinalphos and chloropyrifos) were selected as target analytes as they are widely used in agriculture sector. Various parameters affecting the extraction efficiency of the imprinted polymers have been evaluated to optimize the selective preconcentration of OPPs from aqueous samples. The characteristics of the MIP-SPE method were validated by high performance liquid chromatography (HPLC). The accuracy and selectivity of the MIP-SPE process developed were verified using non-imprinted polymer solid phase extraction (NIP-SPE) and a commercial C 18 -SPE was used for comparison. The recoveries of the target analytes obtained using the MIPs as the solid phase sorbent ranged from 83% to 98% (RSDs 1.05 - 1.98 %; n=3) for water sample. The developed MIP-SPE method demonstrates that it could be applied for the determination of OPPs in water samples. (author)

Extraction of three bioactive diterpenoids from Andrographis paniculata: effect of the extraction techniques on extract composition and quantification of three andrographolides using high-performance liquid chromatography.

Science.gov (United States)

Kumar, Satyanshu; Dhanani, Tushar; Shah, Sonal

2014-10-01

Andrographis paniculata (Burm.f.) wall.ex Nees (Acanthaceae) or Kalmegh is an important medicinal plant finding uses in many Ayurvedic formulations. Diterpenoid compounds andrographolides (APs) are the main bioactive phytochemicals present in leaves and herbage of A. paniculata. The efficiency of supercritical fluid extraction (SFE) using carbon dioxide was compared with the solid-liquid extraction techniques such as solvent extraction, ultrasound-assisted solvent extraction and microwave-assisted solvent extraction with methanol, water and methanol-water as solvents. Also a rapid and validated reverse-phase high-performance liquid chromatography-diode array detection method was developed for the simultaneous determination of the three biologically active compounds, AP, neoandrographolide and andrograpanin, in the extracts of A. paniculata. Under the best SFE conditions tested for diterpenoids, which involved extraction at 60°C and 100 bar, the extractive efficiencies were 132 and 22 µg/g for AP and neoandrographolide, respectively. The modifier percentage significantly affected the extraction efficiency. © The Author [2013]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Kinetic of liquid-liquid extraction for uranyl nitrate and actinides (III) and lanthanides (III) nitrates by amide extractants; Cinetique d`extraction liquide-liquide du nitrate d`uranyle et des nitrates d`actinides (III) et de lanthanides (III) par des extractants a fonction amide

Energy Technology Data Exchange (ETDEWEB)

Toulemonde, V [CEA Centre d` Etudes Nucleaires de Saclay, 91 -Gif-sur-Yvette (France); [CEA Centre d` Etudes de la Vallee du Rhone, 30 -Marcoule (France). Dept. d` Exploitation du Retraitement et de Demantelement

1995-12-20

The kinetics of liquid-liquid extraction by amide extractants have been investigated for uranyl nitrate (monoamide extractants), actinides (III) and lanthanides (III) nitrates (diamide extractants). The transfer of the metallic species from the aqueous phase to the organic phase was studied using two experimental devices: ARMOLLEX (Argonne Modified Lewis cell for Liquid Liquid Extraction) and RSC (Rotating Stabilized Cell). The main conclusions are: for the extraction of uranyl nitrate by DEHDMBA monoamide, the rate-controlling step is the complexation of the species at the interface of the two liquids. Thus, an absorption-desorption (according to Langmuir theory) reaction mechanism was proposed; for the extraction of actinides (III) and lanthanides (III) nitrates in nitric acid media by DMDBTDMA diamide, the kinetic is also limited by interfacial reactions. The behavior of Americium and Europium is very similar as fare as their reaction kinetics are concerned. (author). 89 refs.

Critical comparison of the on-line and off-line molecularly imprinted solid-phase extraction of patulin coupled with liquid chromatography.

Science.gov (United States)

Lhotská, Ivona; Holznerová, Anežka; Solich, Petr; Šatínský, Dalibor

2017-12-01

Reaching trace amounts of mycotoxin contamination requires sensitive and selective analytical tools for their determination. Improving the selectivity of sample pretreatment steps covering new and modern extraction techniques is one way to achieve it. Molecularly imprinted polymers as selective sorbent for extraction undoubtedly meet these criteria. The presented work is focused on the hyphenation of on-line molecularly imprinted solid-phase extraction with a chromatography system using a column-switching approach. Making a critical comparison with a simultaneously developed off-line extraction procedure, evaluation of pros and cons of each method, and determining the reliability of both methods on a real sample analysis were carried out. Both high-performance liquid chromatography methods, using off-line extraction on molecularly imprinted polymer and an on-line column-switching approach, were validated, and the validation results were compared against each other. Although automation leads to significant time savings, fewer human errors, and required no handling of toxic solvents, it reached worse detection limits (15 versus 6 μg/L), worse recovery values (68.3-123.5 versus 81.2-109.9%), and worse efficiency throughout the entire clean-up process in comparison with the off-line extraction method. The difficulties encountered, the compromises made during the optimization of on-line coupling and their critical evaluation are presented in detail. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Separation of Asphaltenes by Polarity using Liquid-Liquid Extraction

DEFF Research Database (Denmark)

Andersen, Simon Ivar

1997-01-01

In order to investigate the nature of petroleum asphaltenes in terms of polarity a process was developed using initial liquid-liquid extraction of the oil phase followed by precipitation of the asphaltenes using n-heptane. The liquid-liquid extraction was performed using toluene-methanol mixtures...... phase. The asphaltenes were analysed using FTir, Elemental analysis, and HPLC-SEC with a diode array detector. With increasing content of toluene in the methanol the molecular weight distribution of the asphaltenes significantly move to higher molecular weights. The content of nitrogen and sulfur...

Liquid-Liquid Extraction in Systems Containing Butanol and Ionic Liquids – A Review

Directory of Open Access Journals (Sweden)

Kubiczek Artur

2017-03-01

Full Text Available Room-temperature ionic liquids (RTILs are a moderately new class of liquid substances that are characterized by a great variety of possible anion-cation combinations giving each of them different properties. For this reason, they have been termed as designer solvents and, as such, they are particularly promising for liquid-liquid extraction, which has been quite intensely studied over the last decade. This paper concentrates on the recent liquid-liquid extraction studies involving ionic liquids, yet focusing strictly on the separation of n-butanol from model aqueous solutions. Such research is undertaken mainly with the intention of facilitating biological butanol production, which is usually carried out through the ABE fermentation process. So far, various sorts of RTILs have been tested for this purpose while mostly ternary liquid-liquid systems have been investigated. The industrial design of liquid-liquid extraction requires prior knowledge of the state of thermodynamic equilibrium and its relation to the process parameters. Such knowledge can be obtained by performing a series of extraction experiments and employing a certain mathematical model to approximate the equilibrium. There are at least a few models available but this paper concentrates primarily on the NRTL equation, which has proven to be one of the most accurate tools for correlating experimental equilibrium data. Thus, all the presented studies have been selected based on the accepted modeling method. The reader is also shown how the NRTL equation can be used to model liquid-liquid systems containing more than three components as it has been the authors’ recent area of expertise.

Automated methods for thorium determination in liquids, solids and aerosols

International Nuclear Information System (INIS)

Robertson, R.; Stuart, J.E.

1984-01-01

Methodology for determining trace thorium levels in a variety of sample types for compliance purposes was developed. Thorium in filtered water samples is concentrated by ferric hydroxide co-precipitation. Aerosols on glass-fibre, cellulose ester or teflon filters are acid digested and thorium is concentrated by lanthanum fluoride co-precipitation. Chemical separation and measurement are then done on a Technicon AAII-C auto-analyzer via TTA-solvent extraction and colorimetry using the thorium-arsenazo III colour complex. Solid samples are acid digested and thorium is concentrated and separated using lanthanum fluoride co-precipitation followed by anion-exchange chromatography. Measurement is then carried out on the autoanalyzer by direct development of the thorium-arsenazo III colour complex. Chemical yields are determined through the addition of thorium-234 tracer with assay by gamma-ray spectrometry. The sensitivities of the methods for liquids, aerosols and solids are approximately 1μg/L,0.5μg and 0.5 μg/g respectively. At thorium levels about ten times the detection limits, accuracy and reproducibility are typically +-10 percent for liquids and aerosols and +- 15 percent for solid samples

Probing solids and liquids

International Nuclear Information System (INIS)

Martin, D.H.

1977-01-01

The wide application of scattering experiments in the study of the structures of solids and liquids is surveyed. Part 1 of the review (Martin. Contemp. Phys.;vol. 18, No. 1: Jan. 1977:pp. 81-98) showed how the angular distribution of a scattered beam of photons or neutrons is related by Fourier transform to the space and time-dependent distributions of electrons and nuclei in the scattering target. The use of x-rays and of neutrons in determining time-averaged density distributions was examined. In this part the time-dependent aspects of the distributions for solids and liquids, including helium, are discussed. The dynamical distributions of magnetism (or angular momentum) density are considered, and the present limitations and future possibilities of scattering experiments are examined. (U.K.)

Studies on supercritical fluid extraction of uranium and thorium from liquid and solid matrix

International Nuclear Information System (INIS)

Kumar, Pradeep; Pal, Ankita; Saxena, M.K.; Ramakumar, K.L.

2006-05-01

Supercritical fluid extraction (SFE) is being widely used in pharmaceutical and food industry. Because of its simplicity, ease of operation and more importantly the reduction in the analytical waste generation, this technique is being viewed as a potential application technique in nuclear industry also. CO 2 is employed as supercritical fluid (SCF) as it is easily recyclable, non-toxic, chemically inert, radiochemically stable and inexpensive. Radioanalytical chemistry section (Radiochemistry and Isotope group) has recently procured a supercritical fluid extraction/chromatography system. The present report describes the work carried out on the system. Detailed study on uranium and thorium extraction from highly acidic medium and tissue paper matrix has been carried out. Direct dissolution and extraction of uranium compounds employing SCF has been carried out. CO 2 was employed as supercritical fluid along with very small amount of Tri n-butyl phosphate (TBP) and Tri n-octyl phosphine oxide (TOPO) as co-solvents. The effect of various operating parameters like CO 2 flow rate, co-solvent percentage, temperature and pressure on extraction was investigated and parameters for maximum extraction were optimized. For comparison, the modes of extraction viz. static and dynamic and modes of complexation viz. in-situ and online were studied. Uranium extraction of ∼98% has been achieved from nitric acid medium employing TBP as co-solvent in 30 minutes extraction time, whereas with TOPO ∼99% uranium extraction could be achieved. Uranium from tissue paper matrix could be extracted upto the extent of 98% with TOPO as co-solvent whereas with TBP extraction of (66.83± 9.80)% was achievable. Direct dissolution of UO 2 , U 3 O 8 , U metal, U-Al alloy solids into SCF CO 2 was carried out employing TBP-HNO 3 complex and SFE of uranium was performed using TBP as co-solvent. UO 2 and U 3 O 8 solids could be dissolved within 20 minutes and extraction of ∼98% was achieved. For U

Transuranium element purification by liquid-liquid extraction

International Nuclear Information System (INIS)

Madic, C.; Koehly, G.

1976-01-01

In the transuranium element production, the liquid-liquid extraction purification is presented. The affinity of TBP and trilaurylammonium nitrate for these elements is given. Exemples of NP/Pu, Pu/Np, U/Pu, Am/Cm, Am and Cm/Ln separation are presented [fr

An inkjet-printed microfluidic device for liquid-liquid extraction.

Science.gov (United States)

Watanabe, Masashi

2011-04-07

A microfluidic device for liquid-liquid extraction was quickly produced using an office inkjet printer. An advantage of this method is that normal end users, who are not familiar with microfabrication, can produce their original microfluidic devices by themselves. In this method, the printer draws a line on a hydrophobic and oil repellent surface using hydrophilic ink. This line directs a fluid, such as water or xylene, to form a microchannel along the printed line. Using such channels, liquid-liquid extraction was successfully performed under concurrent and countercurrent flow conditions. © The Royal Society of Chemistry 2011

One-step extraction of polar drugs from plasma by Parallel Artificial Liquid Membrane Extraction

DEFF Research Database (Denmark)

Pilařová, Veronika; Sultani, Mumtaz; Ask, Kristine Skoglund

2017-01-01

in the pores of a thin polymeric membrane, a well-known extraction principle also used in hollow fiber liquid-phase microextraction (HF-LPME). However, the new PALME technique offers a more user-friendly setup in which the supported liquid membrane is incorporated in a 96 well plate system. Thus, high......The new microextraction technique named parallel artificial liquid membrane extraction (PALME) was introduced as an alternative approach to liquid-liquid extraction of charged analytes from aqueous samples. The concept is based on extraction of analytes across a supported liquid membrane sustained...... for extraction of polar basic drugs was developed in the present work. The basic drugs hydralazine, ephedrine, metaraminol, salbutamol, and cimetidine were used as model analytes, and were extracted from alkalized human plasma into an aqueous solution via the supported liquid membrane. The extraction...

Systematic Assessment of Seven Solvent and Solid-Phase Extraction Methods for Metabolomics Analysis of Human Plasma by LC-MS

Science.gov (United States)

Sitnikov, Dmitri G.; Monnin, Cian S.; Vuckovic, Dajana

2016-12-01

The comparison of extraction methods for global metabolomics is usually executed in biofluids only and focuses on metabolite coverage and method repeatability. This limits our detailed understanding of extraction parameters such as recovery and matrix effects and prevents side-by-side comparison of different sample preparation strategies. To address this gap in knowledge, seven solvent-based and solid-phase extraction methods were systematically evaluated using standard analytes spiked into both buffer and human plasma. We compared recovery, coverage, repeatability, matrix effects, selectivity and orthogonality of all methods tested for non-lipid metabolome in combination with reversed-phased and mixed-mode liquid chromatography mass spectrometry analysis (LC-MS). Our results confirmed wide selectivity and excellent precision of solvent precipitations, but revealed their high susceptibility to matrix effects. The use of all seven methods showed high overlap and redundancy which resulted in metabolite coverage increases of 34-80% depending on LC-MS method employed as compared to the best single extraction protocol (methanol/ethanol precipitation) despite 7x increase in MS analysis time and sample consumption. The most orthogonal methods to methanol-based precipitation were ion-exchange solid-phase extraction and liquid-liquid extraction using methyl-tertbutyl ether. Our results help facilitate rational design and selection of sample preparation methods and internal standards for global metabolomics.

Ultra-preconcentration and determination of selected pharmaceutical and personal care products in different water matrices by solid-phase extraction combined with dispersive liquid-liquid microextraction prior to ultra high pressure liquid chromatography tandem mass spectrometry analysis.

Science.gov (United States)

Celano, Rita; Piccinelli, Anna Lisa; Campone, Luca; Rastrelli, Luca

2014-08-15

Pharmaceutical and personal care products (PPCPs) are one of the most important classes of emerging contaminants. The potential of ecological and environmental impacts associated with PPCPs are of particular concern because they continually penetrate the aquatic environment. This work describes a novel ultra-preconcentration technique for the rapid and highly sensitive analysis of selected PPCPs in environmental water matrices at ppt levels. Selected PPCPs were rapidly extracted and concentrated from large volumes of aqueous solutions (500 and 250mL) by solid-phase extraction combined with dispersive liquid-liquid microextraction (SPE-DLLME) and then analyzed using UHPLC-MS/MS. Experimental parameters were carefully investigated and optimized to achieve the best SPE-DLLME efficiency and higher enrichment factors. The best results were obtained using the ternary mixture acetonitrile/methanol/dichloromethane 3:3:4, v/v/v, both as SPE eluent and DLLME extractant/dispersive mixture. DLLME aqueous solution (5% NaCl, 10mgL(-1) TBAB) was also modified to improve the extraction efficiency of more hydrophilic PPCPs. Under the optimal conditions, an exhaustive extraction for most of the investigated analytes (recoveries >70%), with a precision (RSD drinking, sea, river and wastewater). Method detection and quantification limits were at very low ppt levels and below 1 and 3ngL(-1), respectively, for 15 of selected PPCPs. The proposed analytical procedure offers numerous advantages such as the simplicity of operation, rapidity, a high enrichment factor and sensitivity. So it is suitable for monitoring and studies of occurrence of PPCPs in different environmental compartments. Copyright © 2014 Elsevier B.V. All rights reserved.

Micro-focused ultrasonic solid-liquid extraction (muFUSLE) combined with HPLC and fluorescence detection for PAHs determination in sediments: optimization and linking with the analytical minimalism concept.

Science.gov (United States)

Capelo, J L; Galesio, M M; Felisberto, G M; Vaz, C; Pessoa, J Costa

2005-06-15

Analytical minimalism is a concept that deals with the optimization of all stages of an analytical procedure so that it becomes less time, cost, sample, reagent and energy consuming. The guide-lines provided in the USEPA extraction method 3550B recommend the use of focused ultrasound (FU), i.e., probe sonication, for the solid-liquid extraction of Polycyclic Aromatic Hydrocarbons, PAHs, but ignore the principle of analytical minimalism. The problems related with the dead sonication zones, often present when high volumes are sonicated with probe, are also not addressed. In this work, we demonstrate that successful extraction and quantification of PAHs from sediments can be done with low sample mass (0.125g), low reagent volume (4ml), short sonication time (3min) and low sonication amplitude (40%). Two variables are here particularly taken into account for total extraction: (i) the design of the extraction vessel and (ii) the solvent used to carry out the extraction. Results showed PAHs recoveries (EPA priority list) ranged between 77 and 101%, accounting for more than 95% for most of the PAHs here studied, as compared with the values obtained after soxhlet extraction. Taking into account the results reported in this work we recommend a revision of the EPA guidelines for PAHs extraction from solid matrices with focused ultrasound, so that these match the analytical minimalism concept.

Ionic Liquids as Extraction Media for Metal Ions

Science.gov (United States)

Hirayama, Naoki

In solvent extraction separation of metal ions, recently, many researchers have investigated possible use of hydrophobic ionic liquids as extraction media instead of organic solvents. Ionic liquids are salts of liquid state around room temperature and can act not only as solvents but also as ion-exchangers. Therefore, the extraction mechanism of metal ions into ionic liquids is complicated. This review presents current overview and perspective on evaluation of nature of hydrophobic ionic liquids as extraction media for metal ions.

High performance preconcentration of inorganic Se species by dispersive micro-solid phase extraction with a nanosilica-ionic liquid hybrid material

Science.gov (United States)

Llaver, Mauricio; Coronado, Eduardo A.; Wuilloud, Rodolfo G.

2017-12-01

A highly sensitive and efficient dispersive micro-solid phase extraction (D-μ-SPE) method was developed for inorganic Se speciation analysis. A novel ionic liquid (IL)-nanomaterial hybrid consisting of 1-dodecyl-3-methylimidazolium bromide-functionalized nanosilica was used for the efficient retention of Se(IV) complexed with ammonium pyrrolidine dithiocarbamate, followed by elution with an ethyl acetate/Triton X-114 mixture and determination by electrothermal atomic absorption spectroscopy. The Se(VI) species was selectively determined by difference between total inorganic Se and Se(IV) after pre-reduction. The IL-nanomaterial hybrid was characterized by Fourier transform infrared spectroscopy and transmission electronic microscopy. Likewise, Se(IV) sorption capacity of the retention material and maximum amount of IL loaded on its surface were determined. Several factors concerning the functionalization, extraction and elution steps were optimized, yielding a 100% extraction efficiency for Se(IV) under optimal conditions. A limit of detection of 1.1 ng L- 1, a relative standard deviation of 5.7% and a 110-fold enhancement factor were obtained. The D-μ-SPE method was successfully applied to several water samples from different origins and compositions, including rain, tap, underground, river and sea.

Simultaneous detection of nine cyanotoxins in drinking water using dual solid-phase extraction and liquid chromatography-mass spectrometry.

Science.gov (United States)

Yen, Hung-Kai; Lin, Tsair-Fuh; Liao, Pao-Chi

2011-08-01

A solid-phase extraction (SPE)-liquid chromatography (LC)-mass spectrometry (MS) method was developed to concentrate and detect nine cyanotoxins simultaneously, including six microcystins (MCs) congeners, nodularin (NOD), anatoxin-a (ATX) and cylindrospermopsin (CYN), in pure and natural waters. A dual cartridge SPE assembly was tested for the operating parameters of cyanotoxin extraction. A surrogate standard (SS), 1,9-diaminononane, was spiked in all the samples before the SPE extraction, and an internal standard (IS), 2,3,5-trimethylphenyl methyl carbamate, was spiked before LC/MS analysis. The method detection limit (MDL) was 2-100 ng/L for nine cyanotoxins in pure water and was increased by a factor of three to ten in a more complicated water matrix. The recoveries based on SS were between 83 and 104%, while those based on IS were 80-120%. The developed method was successfully employed in analyzing 33 water samples collected from eutrophic lakes, water treatment plants and distribution taps. MCs, NOD, and CYN were detected in the reservoir water, with concentrations as high as 36 μg/L. In addition, for the first time in Taiwan's tap water, CYN was detected at concentrations as high as 8.6 μg/L. Quality control data for the field samples shows that the analytical scheme developed is appropriate for monitoring cyanotoxins. Copyright © 2011 Elsevier Ltd. All rights reserved.

Graphene and graphene oxide modified by deep eutectic solvents and ionic liquids supported on silica as adsorbents for solid-phase extraction

Energy Technology Data Exchange (ETDEWEB)

Wang, Xiaoqin; Li, Guizhen; Row, Kyung Ho [Dept. of Chemistry and Chemical Engineering, Inha University, Incheon (Korea, Republic of)

2017-02-15

A novel deep eutectic solvent (DES) and ionic liquid (IL)-modified graphene (G) and graphene oxide (GO) were synthesized and used as effective adsorbents for the preconcentration of three chlorophenols (CPs), 4-chlorophenol (4-CP), 2,4-dichlorophenol (2,4-DCP), and 2,4,6-trichlorophenol (2,4,6-TCP), in environmental water samples prior to high-performance liquid chromatography (HPLC). The new materials were characterized by scanning electron microscopy (S-4200) and Fourier-transform infrared spectrometry. The prepared functionalized GO@silica shows remarkable adsorption capacity toward CPs. When used as solid-phase extraction (SPE) sorbents, a superior recovery (88.49–89.70%) could be obtained compared to commercial sorbents, such as silica and aminosilica. Based on this, a method for the analysis of CPs in water samples was established by coupling SPE with HPLC. These results highlight the potential new role of DES and IL-modified GO in the preparation of analytical samples.

Poly(Dimethylsiloxane)-Poly(Vinyl Alcohol) Coated Solid Phase Micro extraction Fiber for Chloropyrifos Analysis

International Nuclear Information System (INIS)

Wan Aini Wan Ibrahim; Nor Fairul Zukry Ahmad Rasdy; Norfazilah Muhamad

2016-01-01

Traditional liquid - liquid extraction of pesticides consumes large volumes of organic solvent which are hazardous to the operator and is not environment friendly. Solid phase micro extraction (SPME) is a solvent less extraction method which is safer to the operator and is environmental friendly. A sol-gel hybrid fibre coating material, poly(dimethylsiloxane)-poly(vinyl alcohol) (PDMS-PVA) was synthesized and used in head space solid phase micro extraction (HS-SPME) of chloropyrifos. The thickness of the synthesised PDMS-PVA fiber coating was 13.5 μm and it is thermally stable up to 400 degree Celsius. The PDMS-PVA sol-gel hybrid fiber was also stable to two organic solvents tested; acetonitrile and dichloromethane (1 hour dipping) and showed no significant changes in extraction performance for chloropyrifos. Extracted chloropyrifos was analysed using gas chromatography electron capture detector (GC-ECD). Optimum SPME parameters affecting the PDMS-PVA HS-SPME performance namely extraction time (15 min), extraction temperature (50 degree Celsius), desorption time (5 min), desorption temperature (260 degree Celsius) and stirring rate (120 rpm) were used for extraction. It was found that HSSPME using PDMS-PVA sol-gel fiber gave significantly better extraction performance of chloropyrifos compared to commercial 100 μm PDMS fiber. The PDMS-PVA fiber showed excellent operational performances such as temperature stability (up to 380 degree Celsius), coating lifetime (up to 170 times use) and organic solvent stability. The PDMS-PVA-HS-SPME method showed excellent recovery for chloropyrifos from tomatoes (98.0 %, 5.9 % RSD) at 0.01 μg/ g spiked level (5 times lower than maximum residue limit set by European Union). (author)

Core-Shell Diamond as a Support for Solid-Phase Extraction and High-Performance Liquid Chromatography

Energy Technology Data Exchange (ETDEWEB)

Saini, Gaurav; Jensen, David S.; Wiest, Landon A.; Vail, Michael A.; Dadson, Andrew; Lee, Milton L.; Shutthanandan, V.; Linford, Matthew R.

2010-06-01

We report the formation of core-shell diamond particles for solid phase extraction (SPE) and high performance liquid chromatography (HPLC) made by layer-by-layer (LbL) deposition. Their synthesis begins with the amine functionalization of microdiamond by its immersion in an aqueous solution of a primary amine-containing polymer (polyallylamine (PAAm)). The amine-terminated microdiamond is then immersed in an aqueous suspension of nanodiamond, which leads to adsorption of the nanodiamond. Alternating (self-limiting) immersions in the solutions of the amine-containing polymer and the suspension of nanodiamond are continued until the desired number of nanodiamond layers is formed around the microdiamond. Finally, the core-shell particles are cross-linked with 1,2,5,6-diepoxycyclooctane or reacted with 1,2-epoxyoctadecane. Layer-by-layer deposition of PAAm and nanodiamond is also studied on planar Si/SiO2 surfaces, which were characterized by SEM, Rutherford backscattering spectrometry (RBS) and nuclear reaction analysis (NRA). Core-shell particles are characterized by diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), environmental scanning electron microscopy (ESEM), and Brunauer Emmett Teller (BET) surface area and pore size measurements. Larger (ca. 50 μm) core-shell diamond particles have much higher surface areas, and analyte loading capacities in SPE than nonporous solid diamond particles. Smaller (ca. 3 μm), normal and reversed phase, core-shell diamond particles have been used for HPLC, with 36,300 plates per meter for mesitylene in a separation of benzene and alkyl benzenes on a C18 adsorbent, and 54,800 plates per meter for diazinon in a similar separation of two pesticides.

Core-shell diamond as a support for solid-phase extraction and high-performance liquid chromatography.

Science.gov (United States)

Saini, Gaurav; Jensen, David S; Wiest, Landon A; Vail, Michael A; Dadson, Andrew; Lee, Milton L; Shutthanandan, V; Linford, Matthew R

2010-06-01

We report the formation of core-shell diamond particles for solid-phase extraction (SPE) and high-performance liquid chromatography (HPLC) made by layer-by-layer (LbL) deposition. Their synthesis begins with the amine functionalization of microdiamond by its immersion in an aqueous solution of a primary amine-containing polymer (polyallylamine (PAAm)). The amine-terminated microdiamond is then immersed in an aqueous suspension of nanodiamond, which leads to adsorption of the nanodiamond. Alternating (self-limiting) immersions in the solutions of the amine-containing polymer and the suspension of nanodiamond are continued until the desired number of nanodiamond layers is formed around the microdiamond. Finally, the core-shell particles are cross-linked with 1,2,5,6-diepoxycyclooctane or reacted with 1,2-epoxyoctadecane. Layer-by-layer deposition of PAAm and nanodiamond is also studied on planar Si/SiO(2) surfaces, which were characterized by scanning electron microscopy (SEM), Rutherford backscattering spectrometry (RBS), and nuclear reaction analysis (NRA). Core-shell particles are characterized by diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), environmental scanning electron microscopy (ESEM), and Brunauer-Emmett-Teller (BET) surface area and pore size measurements. Larger (ca. 50 microm) core-shell diamond particles have much higher surface areas and analyte loading capacities in SPE than nonporous solid diamond particles. Smaller (ca. 3 microm), normal and reversed-phase, core-shell diamond particles have been used for HPLC, with 36,300 plates/m for mesitylene in a separation of benzene and alkyl benzenes and 54,800 plates/m for diazinon in a similar separation of two pesticides on a C(18) adsorbent.

Core-Shell Diamond as a Support for Solid-Phase Extraction and High-Performance Liquid Chromatography

International Nuclear Information System (INIS)

Saini, Gaurav; Jensen, David S.; Wiest, Landon A.; Vail, Michael A.; Dadson, Andrew; Lee, Milton L.; Shutthanandan, V.; Linford, Matthew R.

2010-01-01

We report the formation of core-shell diamond particles for solid phase extraction (SPE) and high performance liquid chromatography (HPLC) made by layer-by-layer (LbL) deposition. Their synthesis begins with the amine functionalization of microdiamond by its immersion in an aqueous solution of a primary amine-containing polymer (polyallylamine (PAAm)). The amine-terminated microdiamond is then immersed in an aqueous suspension of nanodiamond, which leads to adsorption of the nanodiamond. Alternating (self-limiting) immersions in the solutions of the amine-containing polymer and the suspension of nanodiamond are continued until the desired number of nanodiamond layers is formed around the microdiamond. Finally, the core-shell particles are cross-linked with 1,2,5,6-diepoxycyclooctane or reacted with 1,2-epoxyoctadecane. Layer-by-layer deposition of PAAm and nanodiamond is also studied on planar Si/SiO2 surfaces, which were characterized by SEM, Rutherford backscattering spectrometry (RBS) and nuclear reaction analysis (NRA). Core-shell particles are characterized by diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), environmental scanning electron microscopy (ESEM), and Brunauer Emmett Teller (BET) surface area and pore size measurements. Larger (ca. 50 ?m) core-shell diamond particles have much higher surface areas, and analyte loading capacities in SPE than nonporous solid diamond particles. Smaller (ca. 3 ?m), normal and reversed phase, core-shell diamond particles have been used for HPLC, with 36,300 plates per meter for mesitylene in a separation of benzene and alkyl benzenes on a C18 adsorbent, and 54,800 plates per meter for diazinon in a similar separation of two pesticides.

Improved detection limits for phthalates by selective solid-phase micro-extraction

KAUST Repository

Zia, Asif I.

2016-03-30

Presented research reports on an improved method and enhanced limits of detection for phthalates; a hazardous additive used in the production of plastics by solid-phase micro-extraction (SPME) polymer in comparison to molecularly imprinted solid-phase extraction (MISPE) polymer. The polymers were functionalized on an interdigital capacitive sensor for selective binding of phthalate molecules from a complex mixture of chemicals. Both polymers owned predetermined selectivity by formation of valuable molecular recognition sites for Bis (2-ethylhexyl) phthalate (DEHP). Polymers were immobilized on planar electrochemical sensor fabricated on a single crystal silicon substrate with 500 nm sputtered gold electrodes fabricated using MEMS fabrication techniques. Impedance spectra were obtained using electrochemical impedance spectroscopy (EIS) to determine sample conductance for evaluation of phthalate concentration in the spiked sample solutions with various phthalate concentrations. Experimental results revealed that the ability of SPME polymer to adsorb target molecules on the sensing surface is better than that of MISPE polymer for phthalates in the sensing system. Testing the extracted samples using high performance liquid chromatography with photodiode array detectors validated the results.

Dispersive admicelle solid-phase extraction based on sodium dodecyl sulfate coated Fe3 O4 nanoparticles for the selective adsorption of three alkaloids in Gegen-Qinlian oral liquid before high-performance liquid chromatography.

Science.gov (United States)

Shi, Zhihong; Xu, Dan; Zhao, Xuan; Li, Xinghong; Shen, Huimin; Yang, Bing; Zhang, Hongyi

2017-12-01

A novel dispersive admicelle solid-phase extraction method based on sodium dodecyl sulfate-coated Fe 3 O 4 nanoparticles was developed for the selective adsorption of berberine, coptisine, and palmatine in Gegen-Qinlian oral liquid before high-performance liquid chromatography. Fe 3 O 4 nanoparticles were synthesized by a chemical coprecipitation method and characterized by using transmission electron microscopy. Under acidic conditions, the surface of Fe 3 O 4 nanoparticles was coated with sodium dodecyl sulfate to form a nano-sized admicelle magnetic sorbent. Owing to electrostatic interaction, the alkaloids were adsorbed onto the oppositely charged admicelle magnetic nanoparticles. The quick separation of the analyte-adsorbed nanoparticles from the sample solution was performed by using Nd-Fe-B magnet. Best extraction efficiency was achieved under the following conditions: 800 μL Fe 3 O 4 nanoparticles suspension (20 mg/mL), 150 μL sodium dodecyl sulfate solution (10 mg/mL), pH 2, and vortexing time 2 min for the extraction of alkaloids from 10 mL of diluted sample. Four hundred microliters of methanol was used to desorb the alkaloids by vortexing for 1 min. Satisfactory extraction recoveries were obtained in the range of 85.9-120.3%, relative standard deviations for intra- and interday precisions were less than 6.3 and 10.0%, respectively. Finally, the established method was successfully applied to analyze the alkaloids in two batches of Gegen-Qinlian oral liquids. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electromembrane extraction

DEFF Research Database (Denmark)

Huang, Chuixiu; Chen, Zhiliang; Gjelstad, Astrid

2017-01-01

Electromembrane extraction (EME) was inspired by solid-phase microextraction and developed from hollow fiber liquid-phase microextraction in 2006 by applying an electric field over the supported liquid membrane (SLM). EME provides rapid extraction, efficient sample clean-up and selectivity based...

Nitrate conversion and supercritical fluid extraction of UO2-CeO2 solid solution prepared by an electrolytic reduction-coprecipitation method

International Nuclear Information System (INIS)

Zhu, L.Y.; Duan, W.H.; Wen, M.F.; Xu, J.M.; Zhu, Y.J.

2014-01-01

A low-waste technology for the reprocessing of spent nuclear fuel (SNF) has been developed recently, which involves the conversion of actinide and lanthanide oxides with liquid N 2 O 4 into their nitrates followed by supercritical fluid extraction of the nitrates. The possibility of the reprocessing of SNF from high-temperature gas-cooled reactors (HTGRs) with nitrate conversion and supercritical fluid extraction is a current area of research in China. Here, a UO 2 -CeO 2 solid solution was prepared as a surrogate for a UO 2 -PuO 2 solid solution, and the recovery of U and Ce from the UO 2 -CeO 2 solid solution with liquid N 2 O 4 and supercritical CO 2 containing tri-n-butyl phosphate (TBP) was investigated. The UO 2 -CeO 2 solid solution prepared by electrolytic reduction-coprecipitation method had square plate microstructures. The solid solution after heat treatment was completely converted into nitrates with liquid N 2 O 4 . The XRD pattern of the nitrates was similar to that of UO 2 (NO 3 ) 2 . 3H 2 O. After 120 min of online extraction at 25 MPa and 50 , 99.98% of the U and 98.74% of the Ce were recovered from the nitrates with supercritical CO 2 containing TBP. The results suggest a promising potential technology for the reprocessing of SNF from HTGRs. (orig.)

(Liquid + liquid), (solid + liquid), and (solid + liquid + liquid) equilibria of systems containing cyclic ether (tetrahydrofuran or 1,3-dioxolane), water, and a biological buffer MOPS

International Nuclear Information System (INIS)

Altway, Saidah; Taha, Mohamed; Lee, Ming-Jer

2015-01-01

Graphical abstract: - Highlights: • MOPS buffer induced liquid phase splitting for mixtures of water with THF or 1,3-dioxolane. • Phase boundaries of LLE, SLE, and SLLE were determined experimentally. • Tie-lines at LLE and at SLLE were also measured. • Phase diagrams of MOPS + water + THF or 1,3-dioxolane are prepared. • LLE tie-line data are correlated satisfactorily with the NRTL model. - Abstract: Two liquid phases were formed as the addition of a certain amount of biological buffer 3-(N-morpholino)propane sulfonic acid (MOPS) in the aqueous solutions of tetrahydrofuran (THF) or 1,3-dioxolane. To evaluate the feasibility of recovering the cyclic ethers from their aqueous solutions with the aid of MOPS, we determined experimentally the phase diagrams of the ternary systems of {cyclic ether (THF or 1,3-dioxolane) + water + MOPS} at T = 298.15 K under atmospheric pressure. In this study, the solubility data of MOPS in water and in the mixed solvents of water/cyclic ethers were obtained from the results of a series of density measurements, while the (liquid + liquid) and the (solid + liquid + liquid) phase boundaries were determined by visually inspection. Additionally, the tie-line results for (liquid + liquid) equilibrium (LLE) and for (solid + liquid + liquid) equilibrium (SLLE) were measured using an analytical method. The reliability of the experimental LLE tie-line results data was validated by using the Othmer–Tobias correlation. These LLE tie-line values were correlated well with the NRTL model. The phase diagrams obtained from this study reveal that MOPS is a feasible green auxiliary agent to recover the cyclic ethers from their aqueous solutions, especially for 1,3-dioxolane

Determination of bisphenols in beverages by mixed-mode solid-phase extraction and liquid chromatography coupled to tandem mass spectrometry.

Science.gov (United States)

Regueiro, Jorge; Wenzl, Thomas

2015-11-27

Facing growing restrictions on the use of bisphenol A in food contact materials, several bisphenol analogs are arising as major alternatives to replace this chemical in most of its applications. This work reports a simple and robust method based on mixed-mode solid-phase extraction and stable-isotope dilution liquid chromatography-tandem mass spectrometry for the analysis of bisphenol A and its main analogs - bisphenol S, 4,4'-sulfonylbis(2-methylphenol), bisphenol F, bisphenol E, bisphenol B, bisphenol Z, bisphenol AF, bisphenol AP, tetrabromobisphenol A and bisphenol P - in alcoholic and non-alcoholic beverages. Mixed-mode solid-phase extraction, combining cationic exchange and reversed-phase mechanisms, was optimized to provide a selective extraction and purification of the target analytes. Derivatization of bisphenols with pyridine-3-sulfonyl chloride allowed increasing their ionization efficiency by electrospray ionization. Validation of the proposed method was performed in terms of selectivity, matrix effects, linearity, precision, measurement uncertainty, trueness and limits of detection. Satisfactory repeatability and intermediate precision were obtained; the related relative standard deviations were ≤9% and ≤12%, respectively. The relative expanded uncertainty (k=2) was below 20% for all bisphenol analogs and the trueness of the method was demonstrated by recovery experiments. Limits of detection (LOD) ranged from 1.6ngL(-1) to 27.9ngL(-1) for all compounds. Finally, several canned and non-canned beverages were analyzed to demonstrate the applicability of the method. Only bisphenol A and three bisphenol F isomers were detected in any of the samples. Bisphenol A concentration ranged from beverages, at concentration levels up to 0.12 and 0.51μgL(-1), respectively. Copyright © 2015. Published by Elsevier B.V.

Ionizable polyethers as specific metal ion carriers in liquid-liquid extraction and liquid membrane separations

International Nuclear Information System (INIS)

Walkowiak, W.; Charewicz, W.A.; Bartsch, R.A.; Ndip, G.M.

1988-01-01

Consideration is given to results of investigations into competitive extraction and penetration through a liquid membrane of alkali and alkaline earth cations from aqueous solutions by a series of lipophilic and ionizable acyclic polyethers of various molecular structure. It is shown that specificity and selectiviy of cation carriers in liquid-liquid extraction and liquid membrane separation depend on molecular structure of acyclic polyethers

A metastable liquid melted from a crystalline solid under decompression

Science.gov (United States)

Lin, Chuanlong; Smith, Jesse S.; Sinogeikin, Stanislav V.; Kono, Yoshio; Park, Changyong; Kenney-Benson, Curtis; Shen, Guoyin

2017-01-01

A metastable liquid may exist under supercooling, sustaining the liquid below the melting point such as supercooled water and silicon. It may also exist as a transient state in solid-solid transitions, as demonstrated in recent studies of colloidal particles and glass-forming metallic systems. One important question is whether a crystalline solid may directly melt into a sustainable metastable liquid. By thermal heating, a crystalline solid will always melt into a liquid above the melting point. Here we report that a high-pressure crystalline phase of bismuth can melt into a metastable liquid below the melting line through a decompression process. The decompression-induced metastable liquid can be maintained for hours in static conditions, and transform to crystalline phases when external perturbations, such as heating and cooling, are applied. It occurs in the pressure-temperature region similar to where the supercooled liquid Bi is observed. Akin to supercooled liquid, the pressure-induced metastable liquid may be more ubiquitous than we thought.

Integrated Solid-Phase Extraction-Capillary Liquid Chromatography (speLC) Interfaced to ESI-MS/MS for Fast Characterization and Quantification of Protein and Proteomes

DEFF Research Database (Denmark)

Falkenby, Lasse Gaarde; Such-Sanmartín, Gerard; Larsen, Martin Røssel

2014-01-01

min speLC-MS/MS experiment. Analysis by selected reaction monitoring by speLC-SRM-MS/MS of distinct peptides derived from the blood proteins IGF1, IGF2, IBP2, and IBP3 demonstrated protein quantification with CV values below 10% across 96 replicates. The speLC-MS/MS system is ideally suited for fast......The high peptide sequencing speed provided by modern hybrid tandem mass spectrometers enables the utilization of fast liquid chromatographic (LC) separation techniques. We present a robust solid-phase extraction/capillary LC system (speLC) for 5-10 min separation of semicomplex peptide mixtures...

Determination of Niacinamide in Lotions and Creams Using Liquid-Liquid Extraction and High-Performance Liquid Chromatography

Science.gov (United States)

Usher, Karyn M.; Simmons, Carolyn R.; Keating, Daniel W.; Rossi, Henry F., III

2015-01-01

Chemical separations are an important part of an undergraduate chemistry curriculum. Sophomore students often get experience with liquid-liquid extraction in organic chemistry classes, but liquid-liquid extraction is not as often introduced as a quantitative sample preparation method in honors general chemistry or quantitative analysis classes.…

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.

Microsystems for liquid-liquid extraction of radionuclides in the analytical protocols

International Nuclear Information System (INIS)

Helle, Gwendolyne

2014-01-01

Radiochemical analyses are necessary to numerous steps for nuclear wastes management and for the control of the environment. An analytical protocol generally includes different steps of chemical separations which are lengthy, manual and complicated to implement because of their confinement in glove boxes and because of the hostile chemical and radiochemical media. Thus there is a huge importance to propose innovative and robust solutions to automate these steps but also to reduce the volumes of the radioactive and chemical wastes at the end of the analytical cycle. One solution consists in the miniaturization of the analyses through the use of lab-on-chip. The objective of this thesis work was to propose a rational approach to the conception of separative microsystems for the liquid-liquid extraction of radionuclides. To achieve this, the hydrodynamic behavior as well as the extraction performances have been investigated in one chip for three different chemical systems: Eu(III)-HNO 3 /DMDBTDMA, Eu(III)-AcO(H,Na)-HNO 3 /HDEHP and U(VI)-HCl/Aliquat336. A methodology has been developed for the implementation of the liquid-liquid extraction in micro-system for each chemical system. The influence of various geometric parameters such as channel length or specific interfacial area has been studied and the comparison of the liquid-liquid extraction performances has led to highlight the influence of the phases viscosities ratio on the flows. Thanks to the modeling of both hydrodynamics and mass transfer in micro-system, the criteria related to physical and kinetic properties of the chemical systems have been distinguished to propose a rational conception of tailor-made chips. Finally, several examples of the liquid-liquid extraction implementation in micro-system have been described for analytical applications in the nuclear field: U/Co separation by Aliquat336, Eu/Sm separation by DMDBTDMA or even the coupling between a liquid-liquid extraction chip and the system of

A fast, simple and green method for the extraction of carbamate pesticides from rice by microwave assisted steam extraction coupled with solid phase extraction.

Science.gov (United States)

Song, Weitao; Zhang, Yiqun; Li, Guijie; Chen, Haiyan; Wang, Hui; Zhao, Qi; He, Dong; Zhao, Chun; Ding, Lan

2014-01-15

This paper presented a fast, simple and green sample pretreatment method for the extraction of 8 carbamate pesticides in rice. The carbamate pesticides were extracted by microwave assisted water steam extraction method, and the extract obtained was immediately applied on a C18 solid phase extraction cartridge for clean-up and concentration. The eluate containing target compounds was finally analysed by high performance liquid chromatography with mass spectrometry. The parameters affecting extraction efficiency were investigated and optimised. The limits of detection ranging from 1.1 to 4.2ngg(-1) were obtained. The recoveries of 8 carbamate pesticides ranged from 66% to 117% at three spiked levels, and the inter- and intra-day relative standard deviation values were less than 9.1%. Compared with traditional methods, the proposed method cost less extraction time and organic solvent. Copyright © 2013 Elsevier Ltd. All rights reserved.

Solid carbon dioxide to promote the extraction of extra-virgin olive oil

Energy Technology Data Exchange (ETDEWEB)

Zinnai, A.; Venturi, F.; Quartacci, V.F.; Sanmartin, C.; Favati, F.; Andrich, G.

2016-07-01

The use of solid carbon dioxide (dry ice) as a cryogen is widespread in the food industry to produce high quality wines, rich in color and perfumes. The direct addition of carbon dioxide to olives in the solid state before milling represents a fundamental step which characterizes this innovative extraction system. At room temperature conditions solid carbon dioxide evolves directly into the air phase (sublimation), and the direct contact between the cryogen and the olives induces a partial solidification of the cellular water inside the fruits. Since the volume occupied by water in the solid state is higher than that in the liquid state, the ice crystals formed are incompatible with the cellular structure and induce the collapse of the cells, besides promoting the diffusion of the cellular substances in the extracted oil, which is thus enriched with cellular metabolites characterized by a high nutraceutical value. Furthermore, a layer of CO2 remains over the olive paste to preserve it from oxidative degradation. The addition of solid carbon dioxide to processed olives induced a statistically significant increase in oil yield and promoted the accumulation of tocopherols in the lipid phase, whereas a not significant increase in the phenolic fraction of the oil occurred. (Author)

Kinetics of glycoalkaloid hydrolysis and solanidine extraction in liquid-liquid systems

Directory of Open Access Journals (Sweden)

Stanković Mihajlo Z.

2002-01-01

Full Text Available The kinetics of glycoalkaloid hydrolysis and solanidine extraction in Analyzed in this study. obtained from dried and milled potato haulm to to which hydrochlotic acid was added is the first liquid phase, while chloroform trichloroethylene or carbon tetrachlondeisthe second organic, liquid phase. The purpose of this paper was to combine the processes of glycoalkaloid hydrolysis to solanidine and solanidine extraction into one step, and to find the optimal liquid-liquid system for such a process.

Primary metals extraction by liquid membranes

International Nuclear Information System (INIS)

Subramanian, K.N.

1980-01-01

The extraction of copper and uranium by liquid membranes is presented. The recovery of uranium from wet process phosphoric acid is described. The development of this process has progressed through three stages, firstly the chemistry of uranium extraction as it pertains to liquid membrane systems. This was followed by continuous extraction tests on fresh black acid and on aged acid. Results on a 1 litre/minute pilot plant demonstrated that the process could be operated with a minimum of feed pretreatment and about 90% of uranium could be extracted. The extraction of copper from copper leach liquors is also described. (U.K.)

Method development for determination of herbicides and insecticides in surface waters using solid-phase extraction and high performance liquid chromatography

International Nuclear Information System (INIS)

Lebre, Daniel Temponi

2000-01-01

Determination of low concentrations of pesticides in surface and ground waters requires high sensitivity analytical techniques. Solid-Phase Extraction (SPE) has been successfully employed to pre concentrate and extract pesticides compounds from water samples. High Performance Liquid Chromatography (HPLC) coupled with UV/Vis detector was used to separate and quantify the extracted compounds. In this work, samples of surface waters with known concentrations of herbicides (atrazine, simazine and trifluralin) and insecticides (aldicarb, carbofuran and carbaryl) were extracted by using SPE off-line technique. The compounds were separated and quantified by reverse phase HPLC with UV detection at 220 ηm. The extraction efficiency was compared between two columns filled with different materials: C 18 -bonded silica phase (500 mg) and copolymer styrenedivynilbenzene resin (250 mg). The results were evaluated as the percent recovery of compounds obtained using different solvents at different concentrations. The results showed that recovery of the analytes greater than 80 % were obtained in SPE columns filled with C 18 bonded silica phase with 6 mL of acetonitrile. Once the optimum conditions were chosen for simulate water samples, the method was validated through analytical and statistical procedures and applied for surface waters. The suitability of the method was verified for the studied compounds showing good sensitivity, i. e., concentrations within the range of 0.4 to 4.0 μgL -1 of pesticides could be quantified attending the limits proposed by official regulations. (author)

Solid-liquid interfacial energy of aminomethylpropanediol

International Nuclear Information System (INIS)

Ocak, Yavuz; Keslioglu, Kazim; Marasli, Necmettin; Akbulut, Sezen

2008-01-01

The grain boundary groove shapes for equilibrated solid aminomethylpropanediol, 2-amino-2 methyl-1.3 propanediol (AMPD) with its melt were directly observed by using a horizontal temperature gradient stage. From the observed grain boundary groove shapes, the Gibbs-Thomson coefficient (Γ), solid-liquid interfacial energy (σ SL ) and grain boundary energy (σ gb ) of AMPD have been determined to be (5.4 ± 0.5) x 10 -8 K m, (8.5 ± 1.3) x 10 -3 J m -2 and (16.5 ± 2.8) x 10 -3 J m -2 , respectively. The ratio of thermal conductivity of equilibrated liquid phase to solid phase for the AMPD has also been measured to be 1.12 at the melting temperature

Solid-liquid interfacial energy of aminomethylpropanediol

Energy Technology Data Exchange (ETDEWEB)

Ocak, Yavuz; Keslioglu, Kazim; Marasli, Necmettin [Department of Physics, Faculty of Arts and Sciences, Erciyes University, 38039 Kayseri (Turkey); Akbulut, Sezen [Department of Physics, Institute of Science and Technology, Erciyes University, 38039 Kayseri (Turkey)], E-mail: marasli@erciyes.edu.tr

2008-03-21

The grain boundary groove shapes for equilibrated solid aminomethylpropanediol, 2-amino-2 methyl-1.3 propanediol (AMPD) with its melt were directly observed by using a horizontal temperature gradient stage. From the observed grain boundary groove shapes, the Gibbs-Thomson coefficient ({gamma}), solid-liquid interfacial energy ({sigma}{sub SL}) and grain boundary energy ({sigma}{sub gb}) of AMPD have been determined to be (5.4 {+-} 0.5) x 10{sup -8} K m, (8.5 {+-} 1.3) x 10{sup -3} J m{sup -2} and (16.5 {+-} 2.8) x 10{sup -3} J m{sup -2}, respectively. The ratio of thermal conductivity of equilibrated liquid phase to solid phase for the AMPD has also been measured to be 1.12 at the melting temperature.

Systems and methods for monitoring a solid-liquid interface

Science.gov (United States)

Stoddard, Nathan G; Lewis, Monte A.; Clark, Roger F

2013-06-11

Systems and methods are provided for monitoring a solid-liquid interface during a casting process. The systems and methods enable determination of the location of a solid-liquid interface during the casting process.

Determination of phthalates released from paper packaging materials by solid-phase extraction-high-performance liquid chromatography.

Science.gov (United States)

Gao, Xin; Yang, Bofeng; Tang, Zhixu; Luo, Xin; Wang, Fengmei; Xu, Hui; Cai, Xue

2014-01-01

A solid phase extraction (SPE) high-performance liquid chromatography (HPLC) method was developed for the simultaneous determination of 10 phthalic acid esters (dimethyl phthalate, diethyl phthalate, dipropyl phthalate, benzylbutyl phthalate, diisobutyl phthalate, dicyclohexyl phthalate, diamyl phthalate, di-n-hexyl phthalate, di-n-octyl phthalate and di-2-ethylhexyl phthalate) released from food paper packaging materials. The use of distilled water, 3% acetic acid (w/v), 10% ethanol (v/v) and 95% ethanol (v/v) instead of the different types of food simulated the migration of 10 phthalic acid esters from food paper packaging materials; the phthalic acid esters in four food simulants were enriched and purified by a C18 SPE column and nitrogen blowing, and quantified by HPLC with a diode array detector. The chromatographic conditions and extraction conditions were optimized and all 10 of the phthalate acid esters had a maximum absorbance at 224 nm. The method showed limitations of detection in the range of 6.0-23.8 ng/mL the correlation coefficients were greater than 0.9999 in all cases, recovery values ranged between 71.27 and 106.97% at spiking levels of 30, 60 and 90 ng/mL and relative standard deviation values ranged from 0.86 to 8.00%. The method was considered to be simple, fast and reliable for a study on the migration of these 10 phthalic acid esters from food paper packaging materials into food.

Liquid-liquid extraction kinetics of uranyl nitrate and actinides (III)-lanthanides nitrates by extractants with amide function

International Nuclear Information System (INIS)

Toulemonde, V.

1995-01-01

Nowadays, the most important part of electric power is generated by fission energy. But spent fuels have then to be reprocessed. The production of these reprocessed materials separately and with a high purity level is done according to a liquid-liquid extraction process (Purex process) with the use of tributyl phosphate as solvent. Optimization studies concerning the extracting agent have been undertaken. This work gives the results obtained for the uranyl nitrate and the actinides (III)-lanthanides (III) nitrates extraction by extractants with amide function (monoamide for U(VI) and diamide for actinides (III) and lanthanides (III)). The extraction kinetics have been studied in the case of a metallic specie transfer from the aqueous phase towards the organic phase. The experiments show that the nitrates extraction kinetics is limited by the complexation chemical reaction of the species at the interface between the two liquids. An adsorption-desorption interfacial reactional mechanism (Langmuir theory) is proposed for the uranyl nitrate. (O.M.)

Gold catalyzed nickel disilicide formation: a new solid-liquid-solid phase growth mechanism.

Science.gov (United States)

Tang, Wei; Picraux, S Tom; Huang, Jian Yu; Liu, Xiaohua; Tu, K N; Dayeh, Shadi A

2013-01-01

The vapor-liquid-solid (VLS) mechanism is the predominate growth mechanism for semiconductor nanowires (NWs). We report here a new solid-liquid-solid (SLS) growth mechanism of a silicide phase in Si NWs using in situ transmission electron microcopy (TEM). The new SLS mechanism is analogous to the VLS one in relying on a liquid-mediating growth seed, but it is fundamentally different in terms of nucleation and mass transport. In SLS growth of Ni disilicide, the Ni atoms are supplied from remote Ni particles by interstitial diffusion through a Si NW to the pre-existing Au-Si liquid alloy drop at the tip of the NW. Upon supersaturation of both Ni and Si in Au, an octahedral nucleus of Ni disilicide (NiSi2) forms at the center of the Au liquid alloy, which thereafter sweeps through the Si NW and transforms Si into NiSi2. The dissolution of Si by the Au alloy liquid mediating layer proceeds with contact angle oscillation at the triple point where Si, oxide of Si, and the Au alloy meet, whereas NiSi2 is grown from the liquid mediating layer in an atomic stepwise manner. By using in situ quenching experiments, we are able to measure the solubility of Ni and Si in the Au-Ni-Si ternary alloy. The Au-catalyzed mechanism can lower the formation temperature of NiSi2 by 100 °C compared with an all solid state reaction.

Targeting high-performance liquid chromatography-high-resolution mass spectrometry-solid-phase extraction-nuclear magnetic resonance analysis with high-resolution radical scavenging profiles - bioactive secondary metabolites from the endophytic fungus Penicillium namyslowskii

DEFF Research Database (Denmark)

Wubshet, Sileshi Gizachew; Nyberg, Nils; Tejesvi, Mysore V.

2013-01-01

The high-resolution radical scavenging profile of an extract of the endophytic fungus Penicillium namyslowskii was used to target analysis by high-performance liquid chromatography-high-resolution mass spectrometry-solid-phase extraction-nuclear magnetic resonance spectroscopy, i.e., HPLC...... NMR probe designed for 1.7-mm NMR tubes. To further explore the potential of the above HPLC-HRMS-SPE-NMR platform for analysis of endophytic extracts, six peaks displaying no radical scavenging activity were also analyzed. This allowed unambiguous identification of six metabolites, i...... and griseofulvin, directly from crude extract via HPLC-HRMS-SPE-NMR. Dechlorodehydrogriseofulvin was reported for the first time from nature....

Report on the achievements in research and development of a coal liquefaction technology in the Sunshine Project in fiscal 1981. Development of a solvent extraction and liquefaction plant (research and development of solid-liquid separation process); Sekitan ekika gijutsu no kenkyu kaihatsu, yozai chushutsu ekika plant no kaihatsu, koeki bunriho no kenkyu kaihatsu seika hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

1982-03-01

Among researches on solvent extraction and liquefaction technologies in the Sunshine Project in fiscal 1981, this paper describes the achievements in development of a solid-liquid separation technology. In the research of operation of a centrifugal separation device, a solid-liquid separation test was performed on slurry extracted from the Australian Wandoan coal being sub-bituminous coal. The deliming rate has reached 99% equilibrium at an addition rate of 20% by weight of anti-solvent (a kind of normal paraffin, which reduces solubility of part of coal extracts and enhances removal rates of ash and solids by utilizing coagulating action of the extracts). Asphaltene among the liquefaction formed materials may be recovered nearly completely, but the recovery rate for pre-asphaltene was lower. An operation test was also carried out by using slurry extracted in a 1 t/d experimental plant. In the study on operation of a 5-l/h continuous sedimentation and separation device, a maximum effect was derived with addition of anti-solvent at 25% by weight and at a stirring rate of 700 rpm. The solid-liquid separability changes depending on the kind of slurry. The low conversion rate slurry becomes difficult of separation because its viscosity is high and the difference in density between solids and liquid is small. Furthermore, the high conversion rate slurry has become difficult of separation due to small particle size of the solids. (NEDO)

Liquid-liquid extraction by reversed micelles in biotechnological processes

Directory of Open Access Journals (Sweden)

Kilikian B. V.

2000-01-01

Full Text Available In biotechnology there is a need for new purification and concentration processes for biologically active compounds such as proteins, enzymes, nucleic acids, or cells that combine a high selectivity and biocompatibility with an easy scale-up. A liquid-liquid extraction with a reversed micellar phase might serve these purposes owing to its capacity to solubilize specific biomolecules from dilute aqueous solutions such as fermentation and cell culture media. Reversed micelles are aggregates of surfactant molecules containing an inner core of water molecules, dispersed in a continuous organic solvent medium. These reversed micelles are capable of selectively solubilizing polar compounds in an apolar solvent. This review gives an overview of liquid-liquid extraction by reversed micelles for a better understanding of this process.

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.

Crosslinked polymeric ionic liquids as solid-phase microextraction sorbent coatings for high performance liquid chromatography.

Science.gov (United States)

Yu, Honglian; Merib, Josias; Anderson, Jared L

2016-03-18

Neat crosslinked polymeric ionic liquid (PIL) sorbent coatings for solid-phase microextraction (SPME) compatible with high-performance liquid chromatography (HPLC) are reported for the first time. Six structurally different PILs were crosslinked to nitinol supports and applied for the determination of select pharmaceutical drugs, phenolics, and insecticides. Sampling conditions including sample solution pH, extraction time, desorption solvent, desorption time, and desorption solvent volume were optimized using design of experiment (DOE). The developed PIL sorbent coatings were stable when performing extractions under acidic pH and remained intact in various organic desorption solvents (i.e., methanol, acetonitrile, acetone). The PIL-based sorbent coating polymerized from the IL monomer 1-vinyl-3-(10-hydroxydecyl) imidazolium chloride [VC10OHIM][Cl] and IL crosslinker 1,12-di(3-vinylbenzylimidazolium) dodecane dichloride [(VBIM)2C12] 2[Cl] exhibited superior extraction performance compared to the other studied PILs. The extraction efficiency of pharmaceutical drugs and phenolics increased when the film thickness of the PIL-based sorbent coating was increased while many insecticides were largely unaffected. Satisfactory analytical performance was obtained with limits of detection (LODs) ranging from 0.2 to 2 μg L(-1) for the target analytes. The accuracy of the analytical method was examined by studying the relative recovery of analytes in real water samples, including tap water and lake water, with recoveries varying from 50.2% to 115.9% and from 48.8% to 116.6%, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

Solid-phase extraction combined with dispersive liquid-liquid microextraction and chiral liquid chromatography-tandem mass spectrometry for the simultaneous enantioselective determination of representative proton-pump inhibitors in water samples.

Science.gov (United States)

Zhao, Pengfei; Deng, Miaoduo; Huang, Peiting; Yu, Jia; Guo, Xingjie; Zhao, Longshan

2016-09-01

This report describes, for the first time, the simultaneous enantioselective determination of proton-pump inhibitors (PPIs-omeprazole, lansoprazole, pantoprazole, and rabeprazole) in environmental water matrices based on solid-phase extraction combined with dispersive liquid-liquid microextraction (SPE-DLLME) and chiral liquid chromatography-tandem mass spectrometry. The optimized results of SPE-DLLME were obtained with PEP-2 column using methanol-acetonitrile (1/1, v/v) as elution solvent, dichloroethane, and acetonitrile as extractant and disperser solvent, respectively. The separation and determination were performed using reversed-phase chromatography on a cellulose chiral stationary phase, a Chiralpak IC (250 mm × 4.6 mm, 5 μm) column, under isocratic conditions at 0.6 mL min(-1) flow rate. The analytes were detected in multiple reaction monitoring (MRM) mode by triple quadrupole mass spectrometry. Isotopically labeled internal standards were used to compensate matrix interferences. The method provided enrichment factors of around 500. Under optimal conditions, the mean recoveries for all eight enantiomers from the water samples were 89.3-107.3 % with 0.9-10.3 % intra-day RSD and 2.3-8.1 % inter-day RSD at 20 and 100 ng L(-1) levels. Correlation coefficients (r (2)) ≥ 0.999 were achieved for all enantiomers within the range of 2-500 μg L(-1). The method detection and quantification limits were at very low levels, within the range of 0.67-2.29 ng L(-1) and 2.54-8.68 ng L(-1), respectively. This method was successfully applied to the determination of the concentrations and enantiomeric fractions of the targeted analytes in wastewater and river water, making it applicable to the assessment of the enantiomeric fate of PPIs in the environment. Graphical Abstract Simultaneous enantioselective determination of representative proton-pump inhibitors in water samples.

Effect of surfactant Te on the behavior of alumina inclusions at advancing solid-liquid interfaces of liquid steel

International Nuclear Information System (INIS)

Zheng, Lichun; Malfliet, Annelies; Wollants, Patrick; Blanpain, Bart; Guo, Muxing

2016-01-01

The effect of surfactant Te on the behavior of alumina inclusions at advancing solid-liquid interfaces of liquid steel was studied by adding Te to liquid steel before Al deoxidation at 1873 K. After water-quenching, the spatial distribution homogeneity of alumina inclusions in the steel matrix was characterized using the Dirichlet tessellation method. The deterioration of this homogeneity with increasing the addition of Te indicates that Te facilitates pushing of alumina inclusions. This phenomenon was discussed based on the thermodynamics of an asymmetric thin liquid film confined by an advancing solid-liquid interface and a particle. The surface excesses of Te at the solid-liquid and particle-liquid interfaces were theoretically demonstrated to decrease when an alumina inclusion moves towards the solid-liquid interface, thereby weakening the effect of Te on the solid-liquid and particle-liquid interfacial energies. Based on this, effect of surfactants was incorporated in the models predicting the critical velocity V_C.

DETERMINATION OF MUSHROOM TOXIN ALPHA-AMANITIN IN SERUM BY LIQUID CHROMATOGRAPHY-MASS SPECTROMETRY AFTER SOLID-PHASE EXTRACTION

Directory of Open Access Journals (Sweden)

Maja Vujović

2015-03-01

Full Text Available Alpha-amanitin is a cyclic peptide which belongs to a large group of mushroom toxins known as amatoxins. Being responsible for the majority of fatal mushroom poisonings, they require rapid detection and excretion from the body fluids. In accordance with these requirements, a simple and an accurate method was developed for successful identification and quantification of alpha-amanitin in serum with electrospray liquid chromatography–mass spectrometry (LC-ESI-MS after collision-induced dissociation. The method conforms to the established International Conference on Harmonization Q2A/Q2B 1996 guidelines on the validation of analytical methods. Linearity, precision, extraction recovery and stability test on blank serum spiked with alpha-amanitin and stored in different conditions met the acceptance criteria. The obtained calibration curve was linear over the concentration range 5-100 ng/mL with a lower limit of quantification (LOQ of 5 ng/mL and limit of detection (LOD of 2.5 ng/mL. The mean intra- and inter-day precision and accuracy were 6.05% and less than ±15% of nominal values, respectively. The neutral solid phase extraction with copolymer hydrophilic–lipophilic balance cartridges was found optimal for sample preparation with the mean recovery of 91.94%. The proposed method demonstrated high sensitivity and selectivity which can be useful both for clinical and forensic toxicology analysis of alpha-amanitin at low concentrations.

Quantification of 31 illicit and medicinal drugs and metabolites in whole blood by fully automated solid-phase extraction and ultra-performance liquid chromatography-tandem mass spectrometry

DEFF Research Database (Denmark)

Bjørk, Marie Kjærgaard; Simonsen, Kirsten Wiese; Andersen, David Wederkinck

2013-01-01

, and benzodiazepines, was used. In order to increase the efficiency of routine analysis, a robotic system based on automated liquid handling and capable of handling all unit operation for sample preparation was built on a Freedom Evo 200 platform with several add-ons from Tecan and third-party vendors. Solid-phase...... extraction was performed using Strata X-C plates. Extraction time for 96 samples was less than 3 h. Chromatography was performed using an ACQUITY UPLC system (Waters Corporation, Milford, USA). Analytes were separated on a 100 mm × 2.1 mm, 1.7 μm Acquity UPLC CSH C18 column using a 6.5 min 0.1 % ammonia (25...

The method for simultaneous extraction and back extraction in liquid three-phase system and equipment for simultaneous extraction and back extraction in liquid three-phase system

International Nuclear Information System (INIS)

Palyska, W.; Chmielewski, A.G.

1992-01-01

The method for simultaneous extraction and back extraction in liquid three-phase system has been worked out. The equipment designed for that process has been also subject of the patent. The interesting component is extracted first to intermediate phase consists of magnetic solvent keeping two extracting phases separately. The intermediate magnetic liquid has been kept in its position using a stable magnet maintained on the surface of the extraction vessel. Then the component pass from intermediate phase to the third phase as a result of back extraction. Mixing in the extraction and back extraction zones is organized by means of rotating shaft going along the whole apparatus. The extraction and back extraction processes occur simultaneously as a result of continuous flow of solvent in their zones. The single extraction back extraction facilities can be joined in larger batteries. 3 figs

Hydrogen extraction from liquid lithium-lead alloy by gas-liquid contact method

International Nuclear Information System (INIS)

Xie Bo; Weng Kuiping; Hou Jianping; Yang Guangling; Zeng Jun

2013-01-01

Hydrogen extraction experiment from liquid lithium-lead alloy by gas-liquid contact method has been carried out in own liquid lithium-lead bubbler (LLLB). Experimental results show that, He is more suitable than Ar as carrier gas in the filler tower. The higher temperature the tower is, the greater hydrogen content the tower exports. Influence of carrier gas flow rate on the hydrogen content in the export is jagged, no obvious rule. Although the difference between experimental results and literature data, but it is feasible that hydrogen isotopes extraction experiment from liquid lithium-lead by gas-liquid contact method, and the higher extraction efficiency increases with the growth of the residence time of the alloy in tower. (authors)

An approach of ionic liquids/lithium salts based microwave irradiation pretreatment followed by ultrasound-microwave synergistic extraction for two coumarins preparation from Cortex fraxini.

Science.gov (United States)

Liu, Zaizhi; Gu, Huiyan; Yang, Lei

2015-10-23

Ionic liquids/lithium salts solvent system was successfully introduced into the separation technique for the preparation of two coumarins (aesculin and aesculetin) from Cortex fraxini. Ionic liquids/lithium salts based microwave irradiation pretreatment followed by ultrasound-microwave synergy extraction (ILSMP-UMSE) procedure was developed and optimized for the sufficient extraction of these two analytes. Several variables which can potentially influence the extraction yields, including pretreatment time and temperature, [C4mim]Br concentration, LiAc content, ultrasound-microwave synergy extraction (UMSE) time, liquid-solid ratio, and UMSE power were optimized by Plackett-Burman design. Among seven variables, UMSE time, liquid-solid ratio, and UMSE power were the statistically significant variables and these three factors were further optimized by Box-Behnken design to predict optimal extraction conditions and find out operability ranges with maximum extraction yields. Under optimum operating conditions, ILSMP-UMSE showed higher extraction yields of two target compounds than those obtained by reference extraction solvents. Method validation studies also evidenced that ILSMP-UMSE is credible for the preparation of two coumarins from Cortex fraxini. This study is indicative of the proposed procedure that has huge application prospects for the preparation of natural products from plant materials. Copyright © 2015 Elsevier B.V. All rights reserved.

Comparison of TEVAR resin beads, PAN fibers, and ePTFE membranes as a solid support for Aliquat-336 in immobilized liquid extraction chromatography for separation of actinides

International Nuclear Information System (INIS)

Joe Dauner; Steve Workman

2012-01-01

The following paper covers a comparison of two new systems to traditional TEVA R resin systems for the analytical separation of actinides by immobilized liquid-liquid extraction using Aliquat-336. The new systems are using expanded polytetrafluroethane (ePTFE) membrane or polyacrylonitrile (PAN) fibers as the solid support. The systems are compared in two ways. First in how much Aliquat-336 they contain with the Vs, ratio of volume of Aliquat-336 to volume of polymeric support, being 0.158, 0.483, and 0.590 for the TEVA R resin, PAN fibers, and the ePTFE systems, respectively. The second comparison is in their performance capacity of extraction of uranyl chloride anion complex. The fiber and resins systems show similar capacities, and the membrane system being an order of magnitude less than the other systems. A cost comparison demonstrates the savings advantages of using a fiber based support compared with resin and membrane support systems. (author)

Separation of rare earths by liquid-liquid extraction

International Nuclear Information System (INIS)

Helgorsky, M.; Leveque, M.

1978-01-01

The elements of the rare earth family are characterised by very similar chemical properties connected with their special electronic structure. The purification of the rare earths sold by RHONE-POULENC is now done by the liquid-liquid extraction technique. The development of different extracting agents and also counter-current techniques have led to solvent extraction replacing the other fractionation techniques because of its efficiency and low cost. There are usually several possible solutions to the main problem of choosing the extracting agent and its mode of use. The difficulty is to find the most economical one taking account of the thermodynamic and hydrodynamic constraints of the solvent. It is shown how ideas about the separation have changed over the course of the development of the uses of the rare earths, ending finally in an integrated scheme that makes RHONE-POULENC a world leader of manufacturers of separated rare earths [fr

AFM fluid delivery/liquid extraction surface sampling/electrostatic spray cantilever probe

Science.gov (United States)

Van Berkel, Gary J.

2015-06-23

An electrospray system comprises a liquid extraction surface sampling probe. The probe comprises a probe body having a liquid inlet and a liquid outlet, and having a liquid extraction tip. A solvent delivery conduit is provided for receiving solvent liquid from the liquid inlet and delivering the solvent liquid to the liquid extraction tip. An open liquid extraction channel extends across an exterior surface of the probe body from the liquid extraction tip to the liquid outlet. An electrospray emitter tip is in liquid communication with the liquid outlet of the liquid extraction surface sampling probe. A system for analyzing samples, a liquid junction surface sampling system, and a method of analyzing samples are also disclosed.

Self-healing liquid/solid state battery

Science.gov (United States)

Burke, Paul J.; Chung, Brice H.V.; Phadke, Satyajit R.; Ning, Xiaohui; Sadoway, Donald R.

2018-02-27

A battery system that exchanges energy with an external device is provided. The battery system includes a positive electrode having a first metal or alloy, a negative electrode having a second metal or alloy, and an electrolyte including a salt of the second metal or alloy. The positive electrode, the negative electrode, and the electrolyte are in a liquid phase at an operating temperature during at least one portion of operation. The positive electrode is entirely in a liquid phase in one charged state and includes a solid phase in another charged state. The solid phase of the positive electrode includes a solid intermetallic formed by the first and the second metals or alloys. Methods of storing electrical energy from an external circuit using such a battery system are also provided.

Hydrodynamic instability induced liquid--solid contacts in film boiling

International Nuclear Information System (INIS)

Yao, S.; Henry, R.E.

1976-01-01

The film boiling liquid-solid contacts of saturated ethanol and water to horizontal flat gold plated copper are examined by using electric conductance probe. It is observed that the liquid-solid contacts occur over a wide temperature range, and generally, induced by hydrodynamic instabilities. The area of contact decreases exponentially with interface temperature and is liquid depth dependent. The averaged duration of contacts is strongly influenced by the dominant nucleation process, and thus, depends on the interface temperature and the wettability of the solid during the contact. The frequency of major contacts is about 1.5 times the bubble detaching frequency. It is found that the liquid-solid contacts may account for a large percentage of the film boiling heat transfer near the low temperature end of film boiling and decreases as the interface temperature increases

Determination of type A trichothecenes in coix seed by magnetic solid-phase extraction based on magnetic multi-walled carbon nanotubes coupled with ultra-high performance liquid chromatography-tandem mass spectrometry.

Science.gov (United States)

Dong, Maofeng; Si, Wenshuai; Wang, Weimin; Bai, Bing; Nie, Dongxia; Song, Weiguo; Zhao, Zhihui; Guo, Yirong; Han, Zheng

2016-09-01

Magnetic solid-phase extraction (m-SPE) is a promising sample preparation approach due to its convenience, speed, and simplicity. For the first time, a rapid and reliable m-SPE approach using magnetic multi-walled carbon nanotubes (m-MWCNTs) as the adsorbent was proposed for purification of type A trichothecenes including T-2 toxins (T2), HT-2 toxins (HT-2), diacetoxyscirpenol (DAS), and neosolaniol (NEO) in coix seed. The m-MWCNTs were synthesized by assembling the magnetic nanoparticles (Fe3O4) with MWCNTs by sonication through an aggregation wrap mechanism, and characterized by transmission electron microscope. Several key parameters affecting the performance of the procedure were extensively investigated including extraction solutions, desorption solvents, and m-MWCNT amounts. Under the optimal sample preparation conditions followed by analysis with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), high sensitivity (limit of quantification in the range of 0.3-1.5 μg kg(-1)), good linearity (R (2) > 0.99), satisfactory recovery (73.6-90.6 %), and acceptable precision (≤2.5 %) were obtained. The analytical performance of the developed method has also been successfully evaluated in real coix seed samples. Graphical Abstract Flow chart of determination of type A trichothecenes in coix seed by magnetic solid-phase extraction coupled with ultra-high performance liquid chromatography-tandem mass spectrometry.

Rapid determination of six carcinogenic primary aromatic amines in mainstream cigarette smoke by two-dimensional online solid phase extraction combined with liquid chromatography tandem mass spectrometry.

Science.gov (United States)

Bie, Zhenying; Lu, Wei; Zhu, You; Chen, Yusong; Ren, Hubo; Ji, Lishun

2017-01-27

A fully automated, rapid, and reliable method for simultaneous determination of six carcinogenic primary aromatic amines (AAs), including o-toluidine (o-TOL), 2, 6-dimethylaniline (2, 6-DMA), o-anisidine (o-ASD), 1-naphthylamine (1-ANP), 2-naphthylamine (2-ANP), and 4-aminobiphenyl (4-ABP), in mainstream cigarette smoke was established. The proposed method was based on two-dimensional online solid phase extraction combined with liquid chromatography tandem mass spectrometry (SPE/LC-MS/MS). The particulate phase of the mainstream cigarette smoke was collected on a Cambridge filter pad and pretreated via ultrasonic extraction with 2% formic acid (FA), while the gas phase was trapped by 2% FA without pretreatment for determination. The two-dimensional online SPE comprised of two cartridges with different absorption characteristics was applied for sample pretreatment. Analysis was performed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) under multiple reaction monitoring mode. Each sample required about 0.5h for solid phase extraction and analysis. The limit of detections (LODs) for six AAs ranged from 0.04 to 0.58ng/cig and recoveries were within 84.5%-122.9%. The relative standard deviations of intra- and inter-day tests for 3R4F reference cigarette were less than 6% and 7%, respectively, while no more than 7% and 8% separately for a type of Virginia cigarette. The proposed method enabled minimum sample pretreatment, full automation, and high throughput with high selectivity, sensitivity, and accuracy. As a part of the validation procedure, fifteen brands of cigarettes were tested by the designed method. Copyright © 2016 Elsevier B.V. All rights reserved.

Chemistry and physics at liquid alkali metal/solid metal interfaces

International Nuclear Information System (INIS)

Barker, M.G.

1977-01-01

This paper describes the chemistry of processes which take place at the interface between liquid alkali metals and solid metal surfaces. A brief review of wetting data for liquid sodium is given and the significance of critical wetting temperatures discussed on the basis of an oxide-film reduction mechanism. The reactions of metal oxides with liquid metals are outlined and a correlation with wetting data established. The transfer of dissolved species from the liquid metal across the interface to form solid phases on the solid metal surface is well recognised. The principal features of such processes are described and a simple thermodynamic explanation is outlined. The reverse process, the removal of solid material into solution, is also considered. (author)

Bio-dispersive liquid liquid microextraction based on nano rhaminolipid aggregates combined with magnetic solid phase extraction using Fe3O4@PPy magnetic nanoparticles for the determination of methamphetamine in human urine.

Science.gov (United States)

Haeri, Seyed Ammar; Abbasi, Shahryar; Sajjadifar, Sami

2017-09-15

In the present investigation, extraction and preconcentration of methamphetamine in human urine samples was carried out using a novel bio-dispersive liquid liquid microextraction (Bio-DLLME) technique coupled with magnetic solid phase extraction (MSPE). Bio-DLLME is a kind of microextraction technique based nano-materials which have potential capabilities in many application fields. Bio-DLLME is based on the use of a binary part system consisting of methanol and nano rhaminolipid biosurfactant. Use of this binary mixture is ecologically accepted due to their specificity, biocompatibility and biodegradable nature. The potential of nano rhaminolipid biosurfactant as a biological agent in the extraction of organic compounds has been investigated in recent years. They are able to partition at the oil/water interfaces and reduce the interfacial tension in order to increase solubility of hydrocarbons. The properties of the prepared Fe 3 O 4 @PPy magnetic nanoparticles were characterized using Fourier transform infrared spectroscopy and X-ray diffraction methods The influences of the experimental parameters on the quantitative recovery of analyte were investigated. Under optimized conditions, the enrichment factor was 310, the calibration graph was linear in the methamphetamine concentration range from 1 to 60μgL -1 , with a correlation coefficient of 0.9998. The relative standard deviations for six replicate measurements was 5.2%. Copyright © 2017 Elsevier B.V. All rights reserved.

Solid/liquid interfacial free energies in binary systems

Science.gov (United States)

Nason, D.; Tiller, W. A.

1973-01-01

Description of a semiquantitative technique for predicting the segregation characteristics of smooth interfaces between binary solid and liquid solutions in terms of readily available thermodynamic parameters of the bulk solutions. A lattice-liquid interfacial model and a pair-bonded regular solution model are employed in the treatment with an accommodation for liquid interfacial entropy. The method is used to calculate the interfacial segregation and the free energy of segregation for solid-liquid interfaces between binary solutions for the (111) boundary of fcc crystals. The zone of compositional transition across the interface is shown to be on the order of a few atomic layers in width, being moderately narrower for ideal solutions. The free energy of the segregated interface depends primarily upon the solid composition and the heats of fusion of the component atoms, the composition difference of the solutions, and the difference of the heats of mixing of the solutions.

Liquid chromatography-mass spectrometry platform for both small neurotransmitters and neuropeptides in blood, with automatic and robust solid phase extraction

Science.gov (United States)

Johnsen, Elin; Leknes, Siri; Wilson, Steven Ray; Lundanes, Elsa

2015-03-01

Neurons communicate via chemical signals called neurotransmitters (NTs). The numerous identified NTs can have very different physiochemical properties (solubility, charge, size etc.), so quantification of the various NT classes traditionally requires several analytical platforms/methodologies. We here report that a diverse range of NTs, e.g. peptides oxytocin and vasopressin, monoamines adrenaline and serotonin, and amino acid GABA, can be simultaneously identified/measured in small samples, using an analytical platform based on liquid chromatography and high-resolution mass spectrometry (LC-MS). The automated platform is cost-efficient as manual sample preparation steps and one-time-use equipment are kept to a minimum. Zwitter-ionic HILIC stationary phases were used for both on-line solid phase extraction (SPE) and liquid chromatography (capillary format, cLC). This approach enabled compounds from all NT classes to elute in small volumes producing sharp and symmetric signals, and allowing precise quantifications of small samples, demonstrated with whole blood (100 microliters per sample). An additional robustness-enhancing feature is automatic filtration/filter back-flushing (AFFL), allowing hundreds of samples to be analyzed without any parts needing replacement. The platform can be installed by simple modification of a conventional LC-MS system.

Glycerol-based deep eutectic solvents as extractants for the separation of MEK and ethanol via liquid-liquid extraction

NARCIS (Netherlands)

Rodriguez, N.R.; Ferré Güell, J.; Kroon, M.C.

2016-01-01

Four different glycerol-based deep eutectic solvents (DESs) were tested as extracting agents for the separation of the azeotropic mixture {methyl ethyl ketone + ethanol} via liquid-liquid extraction. The selected DESs for this work were: glycerol/choline chloride with molar ratios (4:1) and (2:1),

Evaluation of graphene-based sorbent in the determination of polar environmental contaminants in water by micro-solid phase extraction-high performance liquid chromatography.

Science.gov (United States)

Naing, Nyi Nyi; Li, Sam Fong Yau; Lee, Hian Kee

2016-01-04

A facile method of extraction using porous membrane protected micro-solid phase extraction (μ-SPE) with a graphene-based sorbent followed by high performance liquid chromatography-ultraviolet detector was developed. The reduced graphene oxide (r-GO) (1mg), synthesized from graphite oxide, was enclosed in a polypropylene bag representing the μ-SPE device, which was used for the extraction of estrogens such as estrone, 17β-estradiol, 17α-ethynylestradiol and diethylstilbestrol in water. The r-GO obtained was identified and characterized by Fourier transform infrared, transmission electron microscopy, scanning electron microscopy and thermogravimetric analysis. The sorbent was loaded with sodium dodecyl sulfate by sonication to prevent agglomeration in aqueous solution. With this method, low limits of detection of between 0.24 and 0.52 ng L(-1) were achieved. For estrogen analysis a linear calibration range of 0.01-100 μg L(-1) was obtained, with the coefficients of determination (r(2)) higher than 0.992. This proposed method was successfully applied to determine estrogens in water. Copyright © 2015 Elsevier B.V. All rights reserved.

Analysis of trace levels of sulfonamide and tetracycline antimicrobials in groundwater and surface water using solid-phase extraction and liquid chromatography/mass spectrometry

Science.gov (United States)

Lindsey, M.E.; Meyer, M.; Thurman, E.M.

2001-01-01

A method has been developed for the trace analysis of two classes of antimicrobials consisting of six sulfonamides (SAs) and five tetracyclines (TCs), which commonly are used for veterinary purposes and agricultural feed additives and are suspected to leach into ground and surface water. The method used solid-phase extraction and liquid chromatography/mass spectrometry (LC/MS) with positive ion electrospray. The unique combination of a metal chelation agent (Na2EDTA) with a macroporous copolymer resulted in quantitative recoveries by solid-phase extraction (mean recovery, 98 ?? 12%) at submicrogram-per-liter concentrations. An ammonium formate/formic acid buffer with a methanol/water gradient was used to separate the antimicrobials and to optimize the signal intensity. Mass spectral fragmentation and ionization characteristics were determined for each class of compounds for unequivocal identification. For all SAs, a characteristic m/z 156 ion representing the sulfanilyl fragment was identified. TCs exhibited neutral losses of 17 amu resulting from the loss of ammonia and 35 amu from the subsequent loss of water. Unusual matrix effects were seen only for TCs in this first survey of groundwater and surface water samples from sites around the United States, requiring that TCs be quantitated using the method of standard additions.

Liquid-liquid extraction and separation studies of uranium(VI)

International Nuclear Information System (INIS)

Langade, A.D.; Shinde, V.M.

1980-01-01

Separation of uranium(VI) from iron(III), molybdenum(VI), vanadium(V), bismuth(III), zirconium(IV) and thorium(IV) is achieved by liquid-liquid extraction with 4-methyl-3-pentene-2-one (mesityl oxide; MeO) from sodium salicylate media (0.1M, pH 6.0). The extracted species is UO 2 (HO.C 6 H 4 COO) 2 .2MeO. A procedure for separating 50 μg of uranium from mg amounts of the other metals is described. (author)

Digital microfluidics platform for interfacing solid-liquid extraction column with portable capillary electropherograph for analysis of soil amino acids.

Science.gov (United States)

Gorbatsova, Jelena; Jaanus, Martin; Vaher, Merike; Kaljurand, Mihkel

2016-02-01

In this work, the concept of a field-portable analyzer is proposed that operates with milliliter amounts of solvents and samples. The need to develop such an analyzer is not only driven by specific extraterrestrial analysis but also, for example, by forensics applications where the amount of liquid that can be taken to the field is severely limited. The prototype of the proposed analyzer consists of a solid-liquid extractor, the output of which is connected to the micropump, which delivers droplets of extracts to digital microfluidic platform (DMFP). In this way, world-to-chip interfacing is established. Further, the sample droplets are transported to CE capillary inlet port, separated and detected via a contactless conductivity detector. Working buffers and other solvents needed to perform CE analysis are also delivered as droplets to the DMFP and transported through the CE capillary. The performance of the analyzer is demonstrated by analysis of amino acids in sand matrices. The recovery of the spiked amino acids from the inert sand sample was from 34 to 51% with analysis LOD from 0.2 to 0.6 ppm and migration time RSD from 0.2 to 6.0%. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Rapid Magnetic Solid Phase Extraction Method Followed by Liquid Chromatography-Tandem Mass Spectrometry Analysis for the Determination of Mycotoxins in Cereals.

Science.gov (United States)

Barbera, Giorgia La; Capriotti, Anna Laura; Cavaliere, Chiara; Foglia, Patrizia; Montone, Carmela Maria; Chiozzi, Riccardo Zenezini; Laganà, Aldo

2017-04-21

Mycotoxins can contaminate various food commodities, including cereals. Moreover, mycotoxins of different classes can co-contaminate food, increasing human health risk. Several analytical methods have been published in the literature dealing with mycotoxins determination in cereals. Nevertheless, in the present work, the aim was to propose an easy and effective system for the extraction of six of the main mycotoxins from corn meal and durum wheat flour, i.e., the main four aflatoxins, ochratoxin A, and the mycoestrogen zearalenone. The developed method exploited magnetic solid phase extraction (SPE), a technique that is attracting an increasing interest as an alternative to classical SPE. Therefore, the use of magnetic graphitized carbon black as a suitable extracting material was tested. The same magnetic material proved to be effective in the extraction of mycoestrogens from milk, but has never been applied to complex matrices as cereals. Ultra high-performance liquid chromatography tandem mass spectrometry was used for detection. Recoveries were >60% in both cereals, even if the matrix effects were not negligible. The limits of quantification of the method results were comparable to those obtained by other two magnetic SPE-based methods applied to cereals, which were limited to one or two mycotoxins, whereas in this work the investigated mycotoxins belonged to three different chemical classes.

A Rapid Magnetic Solid Phase Extraction Method Followed by Liquid Chromatography-Tandem Mass Spectrometry Analysis for the Determination of Mycotoxins in Cereals

Directory of Open Access Journals (Sweden)

Giorgia La Barbera

2017-04-01

Full Text Available Mycotoxins can contaminate various food commodities, including cereals. Moreover, mycotoxins of different classes can co-contaminate food, increasing human health risk. Several analytical methods have been published in the literature dealing with mycotoxins determination in cereals. Nevertheless, in the present work, the aim was to propose an easy and effective system for the extraction of six of the main mycotoxins from corn meal and durum wheat flour, i.e., the main four aflatoxins, ochratoxin A, and the mycoestrogen zearalenone. The developed method exploited magnetic solid phase extraction (SPE, a technique that is attracting an increasing interest as an alternative to classical SPE. Therefore, the use of magnetic graphitized carbon black as a suitable extracting material was tested. The same magnetic material proved to be effective in the extraction of mycoestrogens from milk, but has never been applied to complex matrices as cereals. Ultra high–performance liquid chromatography tandem mass spectrometry was used for detection. Recoveries were >60% in both cereals, even if the matrix effects were not negligible. The limits of quantification of the method results were comparable to those obtained by other two magnetic SPE-based methods applied to cereals, which were limited to one or two mycotoxins, whereas in this work the investigated mycotoxins belonged to three different chemical classes.

A novel polymeric ionic liquid-coated magnetic multiwalled carbon nanotubes for the solid-phase extraction of Cu, Zn-superoxide dismutase.

Science.gov (United States)

Wen, Qian; Wang, Yuzhi; Xu, Kaijia; Li, Na; Zhang, Hongmei; Yang, Qin

2016-10-05

A novel magnetic adsorbent, benzyl groups functionalized imidazolium-based polymeric ionic liquid (PIL)-coated magnetic multiwalled carbon nanotubes (MWCNTs) (m-MWCNTs@PIL), has been successfully synthesized and applied for the extraction of Cu, Zn-superoxide dismutase (Cu, Zn-SOD). The m-MWCNTs@PIL were characterized by X-ray diffraction (XRD), Fourier transform infrared spectrometry (FT-IR), thermal gravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), vibrating sample magnetometer (VSM) and zeta-potential nanoparticles. In this method, the m-MWCNTs@PIL could interact with Cu, Zn-SOD through hydrogen bonding, π-π and electrostatic interactions. The extraction performance of the m-MWCNTs@PIL in the magnetic solid-phase extraction (MSPE) procedure was investigated, coupled with the determination by UV-vis spectrophotometer. Compared with m-MWCNTs@IL and m-MWCNTs, the m-MWCNTs@PIL exhibited the highest extraction capacity of 29.1 mg/g for Cu, Zn-SOD. The adsorbed Cu, Zn-SOD remained high specific activity after being eluted from m-MWCNTs@PIL by 1 moL/L NaCl solution. Besides, the m-MWCNTs@PIL could be easily recycled and successfully employed in the extraction of Cu, Zn-SOD from real samples. Under the optimal conditions, the precision, repeatability and stability of the proposed method were investigated and the RSDs were 0.29%, 1.68% and 0.54%, respectively. Recoveries were in the range of 82.7-102.3%, with the RSD between 3.47% and 5.35%. On the basis of these results, the developed method has great potential in the extraction of Cu, Zn-SOD or other analytes from biological samples. Copyright © 2016 Elsevier B.V. All rights reserved.

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.

Sample preparation with solid phase microextraction and exhaustive extraction approaches: Comparison for challenging cases.

Science.gov (United States)

Boyacı, Ezel; Rodríguez-Lafuente, Ángel; Gorynski, Krzysztof; Mirnaghi, Fatemeh; Souza-Silva, Érica A; Hein, Dietmar; Pawliszyn, Janusz

2015-05-11

In chemical analysis, sample preparation is frequently considered the bottleneck of the entire analytical method. The success of the final method strongly depends on understanding the entire process of analysis of a particular type of analyte in a sample, namely: the physicochemical properties of the analytes (solubility, volatility, polarity etc.), the environmental conditions, and the matrix components of the sample. Various sample preparation strategies have been developed based on exhaustive or non-exhaustive extraction of analytes from matrices. Undoubtedly, amongst all sample preparation approaches, liquid extraction, including liquid-liquid (LLE) and solid phase extraction (SPE), are the most well-known, widely used, and commonly accepted methods by many international organizations and accredited laboratories. Both methods are well documented and there are many well defined procedures, which make them, at first sight, the methods of choice. However, many challenging tasks, such as complex matrix applications, on-site and in vivo applications, and determination of matrix-bound and free concentrations of analytes, are not easily attainable with these classical approaches for sample preparation. In the last two decades, the introduction of solid phase microextraction (SPME) has brought significant progress in the sample preparation area by facilitating on-site and in vivo applications, time weighted average (TWA) and instantaneous concentration determinations. Recently introduced matrix compatible coatings for SPME facilitate direct extraction from complex matrices and fill the gap in direct sampling from challenging matrices. Following introduction of SPME, numerous other microextraction approaches evolved to address limitations of the above mentioned techniques. There is not a single method that can be considered as a universal solution for sample preparation. This review aims to show the main advantages and limitations of the above mentioned sample

[Amylase production by Aureobasidium pullulans in liquid and solid media].

Science.gov (United States)

Lodato, P B; Forchiassin, F; Segovia de Huergo, M B

1997-01-01

Amylase production by a strain of Aureobasidium pullulans isolated in the laboratory was evaluated in liquid media (complex and synthetic) and in solid medium (wheat bran). There was an inhibitory effect in amylase production or amylase secretion by glucose. Asparagine was the best nitrogen source for amylase production (4-6 g/l). Only chlamidospores and melanin but not, amylase activity, were obtained with ammonium sulfate. Amylase production in solid culture was higher than the production obtained in the liquid media assayed. Optimum initial moisture content in solid culture ranged between 57 and 74%. No difference was observed in amylase production between solid media inoculated with cells grown in liquid or solid media.

Hybrid Multiphase CFD Solver for Coupled Dispersed/Segregated Flows in Liquid-Liquid Extraction

Directory of Open Access Journals (Sweden)

Kent E. Wardle

2013-01-01

Full Text Available The flows in stage-wise liquid-liquid extraction devices include both phase segregated and dispersed flow regimes. As a additional layer of complexity, for extraction equipment such as the annular centrifugal contactor, free-surface flows also play a critical role in both the mixing and separation regions of the device and cannot be neglected. Traditionally, computional fluid dynamics (CFD of multiphase systems is regime dependent—different methods are used for segregated and dispersed flows. A hybrid multiphase method based on the combination of an Eulerian multifluid solution framework (per-phase momentum equations and sharp interface capturing using Volume of Fluid (VOF on selected phase pairs has been developed using the open-source CFD toolkit OpenFOAM. Demonstration of the solver capability is presented through various examples relevant to liquid-liquid extraction device flows including three-phase, liquid-liquid-air simulations in which a sharp interface is maintained between each liquid and air, but dispersed phase modeling is used for the liquid-liquid interactions.

Isolation and Purification of Unstable Iridoid Glucosides from Traditional Chinese Medicine by Preparative High Performance Liquid Chromatography Coupled with Solid-phase Extraction

Institute of Scientific and Technical Information of China (English)

LI Cun-man; XIAO Yuan-sheng; XUE Xing-ya; FENG Jia-tao; ZHANG Xiu-li; LIANG Xin-miao

2011-01-01

An efficient preparative method was successfully developed for isolation and purification of unstable components from medicinal plant extracts, using a combined method of preparative high performance liquid chro matography(HPLC) and solid-phase extraction(SPE). The aim of this study was to obtain an effective method with high preparative efficiency and importantly to avoid the transformation of unstable compounds. The preparative HPLC system was based on an LC/MS controlled four-channel autopurification system. The SPE method was per formed with a C1s packing material to trap the target compounds and to remove the acidic additive derived from the mobile phase. Using this method, the unstable iridoid glucosides(IGs) as model compounds were successfully iso lated and purified from the extract of Hedyotis diffusa Willd. Six IGs(including one new minor IG) and one nucleo tide compound were simultaneously obtained, each with a purity of ＞91% as determined by HPLC. The structures of the isolated compounds were identified by UPLC/Q-TOF MS, UV, ID and/or 2D NMR. It was demonstrated that the combination of preparative HPLC with SPE is a versatile tool for preparative purification of unstable compounds from complex natural products.

Silica Modified with Polyaniline as a Potential Sorbent for Matrix Solid Phase Dispersion (MSPD) and Dispersive Solid Phase Extraction (d-SPE) of Plant Samples

Science.gov (United States)

Sowa, Ireneusz; Wójciak-Kosior, Magdalena; Strzemski, Maciej; Sawicki, Jan; Staniak, Michał; Dresler, Sławomir; Szwerc, Wojciech; Mołdoch, Jarosław; Latalski, Michał

2018-01-01

Polyaniline (PANI) is one of the best known conductive polymers with multiple applications. Recently, it was also used in separation techniques, mostly as a component of composites for solid-phase microextraction (SPME). In the present paper, sorbent obtained by in situ polymerization of aniline directly on silica gel particles (Si-PANI) was used for dispersive solid phase extraction (d-SPE) and matrix solid–phase extraction (MSPD). The efficiency of both techniques was evaluated with the use of high performance liquid chromatography with diode array detection (HPLC-DAD) quantitative analysis. The quality of the sorbent was verified by Raman spectroscopy and microscopy combined with automated procedure using computer image analysis. For extraction experiments, triterpenes were chosen as model compounds. The optimal conditions were as follows: protonated Si-PANI impregnated with water, 160/1 sorbent/analyte ratio, 3 min of extraction time, 4 min of desorption time and methanolic solution of ammonia for elution of analytes. The proposed procedure was successfully used for pretreatment of plant samples. PMID:29565297

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.

Solid phase extraction of Am(III) and Cm(III) from acidic feeds using tetraethyl diglycolamide (TEDGA) in ionic liquid

NARCIS (Netherlands)

Gujar, R.B.; Ansari, S.A.; Mohapatra, P.K.; Leoncini, Andrea; Verboom, Willem

2016-01-01

Solvent extraction of Am(III) and Cm(III) with several diglycolamide ligands in an ionic liquid, [C4mim][Tf2N] was investigated from nitric acid medium. Based on the encouraging extraction behaviour with N,N,N′,N′-tetraethyldiglycolamide (TEDGA), extraction chromatographic studies were carried out

EPA Method 8321B (SW-846): Solvent-Extractable Nonvolatile Compounds by High Performance Liquid Chromatography-Thermospray-Mass Spectrometry (HPLC-TS-MS) or Ultraviolet (UV) Detection

Science.gov (United States)

Method 8321B describes procedures for preparation and analysis of solid, aqueous liquid, drinking water and wipe samples using high performance liquid chromatography and mass spectrometry for extractable non-volatile compounds.

Synergistic extraction of europium(III) in ammonium ionic liquid

International Nuclear Information System (INIS)

Rout, Alok; Venkatesan, K.A.; Antony, M.P.

2016-01-01

Room temperature ionic liquids have been receiving increased attention for possible applications in the area of nuclear fuel reprocessing and waste management due to their fascinating properties such as good ionicity, high solvation capability, properties tunable etc. Most of the studies in the literature on the extraction of metal ions with molecular extractants dissolved in ionic liquid diluents are making use of the hydrophobic ionic liquids containing imidazolium cations such as the 1-alkyl-3-methylimidazolium ion. From an environmental point of view, such ionic liquids are not suitable as the primary mode of the metal extraction is by cation exchange mechanism wherein ionic liquid cation is lost to the aqueous phase leading to aqueous contamination and issue of recyclability of organic phase. However, there are some hydrophobic ionic liquids such as trioctylmethylammonium chloride ((N 1888 )(Cl)), and trihexyl(tetradecyl)phoshonium chloride (Cyphos IL 101) that exhibit no cation exchange in the aqueous phase during extraction. In this context, the extraction behavior of europium(III) using a neutral extractant, octyl, phenyl-N.N-diisobutylmethylcarbamoylphophinoxide (CMPO) and/or an acidic extractant bis(ethylhexyl)phosphoric acid (D2EHPA) dissolved in the ammonium ionic liquid diluent, trioctylmethylammonium bis(trifluoromethanesulfonyl)imide, (N 1888 )(NTf 2 ). The extraction behavior of CMPO (or D2EHPA)/(N 1888 )((Tf 2 ) system was investigated as a function of different extraction parameters such as feed acidity, extractant concentration, equilibration time etc.

Speciation of As(III) and As(V) in water samples by graphite furnace atomic absorption spectrometry after solid phase extraction combined with dispersive liquid-liquid microextraction based on the solidification of floating organic drop.

Science.gov (United States)

Shamsipur, Mojtaba; Fattahi, Nazir; Assadi, Yaghoub; Sadeghi, Marzieh; Sharafi, Kiomars

2014-12-01

A solid phase extraction (SPE) coupled with dispersive liquid-liquid microextraction based on the solidification of floating organic drop (DLLME-SFO) method, using diethyldithiphosphate (DDTP) as a proper chelating agent, has been developed as an ultra preconcentration technique for the determination of inorganic arsenic in water samples prior to graphite furnace atomic absorption spectrometry (GFAAS). Variables affecting the performance of both steps were thoroughly investigated. Under optimized conditions, 100mL of As(ΙΙΙ) solution was first concentrated using a solid phase sorbent. The extract was collected in 2.0 mL of acetone and 60.0 µL of 1-undecanol was added into the collecting solvent. The mixture was then injected rapidly into 5.0 mL of pure water for further DLLME-SFO. Total inorganic As(III, V) was extracted similarly after reduction of As(V) to As(III) with potassium iodide and sodium thiosulfate and As(V) concentration was calculated by difference. A mixture of Pd(NO3)2 and Mg(NO3)2 was used as a chemical modifier in GFAAS. The analytical characteristics of the method were determined. The calibration graph was linear in the rage of 10-100 ng L(-1) with detection limit of 2.5 ng L(-1). Repeatability (intra-day) and reproducibility (inter-day) of method based on seven replicate measurements of 80 ng L(-1) of As(ΙΙΙ) were 6.8% and 7.5%, respectively. The method was successfully applied to speciation of As(III), As(V) and determination of the total amount of As in water samples and in a certified reference material (NIST RSM 1643e). Copyright © 2014 Elsevier B.V. All rights reserved.

Extraction by means of emulsified liquid membranes; Extraction par membranes liquides emulsionnees (MLE)

Energy Technology Data Exchange (ETDEWEB)

Pareau, D.; Stambouli, M. [Ecole Centrale de Paris, 75 (France)

2006-12-15

It is an alternative of the liquid-liquid extraction process where extraction and stripping are simultaneously carried out. The stripping solution is dispersed in the solvent in micro-droplets. This emulsion, stabilised by a surface-active agent, is then dispersed in the liquid to be treated and, during that step, the metal is transferred to the stripping solution, moving through the solvent which operates as an organic membrane. The paper describes in detail the mechanism of the process, its advantages and its disadvantages. Its field of applications is wide, but only a few units are now industrially in operation, most of them exists only at the pilot scale. It is particularly adapted for the treatment of effluents with a very low content in metallic impurities. As examples, the paper describes the recovery of zinc from viscose plant effluents (Lenzing plant, Austria) and the removal of free cyanide ions and cyanide metallic complexes (pilot scale). (authors)

Three-dimensional ionic liquid functionalized magnetic graphene oxide nanocomposite for the magnetic dispersive solid phase extraction of 16 polycyclic aromatic hydrocarbons in vegetable oils.

Science.gov (United States)

Zhang, Yun; Zhou, Hua; Zhang, Zhe-Hua; Wu, Xiang-Lun; Chen, Wei-Guo; Zhu, Yan; Fang, Chun-Fu; Zhao, Yong-Gang

2017-03-17

In this paper, a novel three-dimensional ionic liquid functionalized magnetic graphene oxide nanocomposite (3D-IL@mGO) was prepared, and used as an effective adsorbent for the magnetic dispersive solid phase extraction (MSPE) of 16 polycyclic aromatic hydrocarbons (PAHs) in vegetable oil prior to gas chromatography-mass spectrometry (GC-MS). The properties of 3D-IL@mGO were characterized by scanning electron micrographs (SEM), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM). The 3D-IL@mGO, functionalized by ionic liquid, exhibited high adsorption toward PAHs. Compared to molecularly imprinted solid phase extraction (MISPE), the MSPE method based on 3D-IL@mGO had less solvent consumption and low cost, and was more efficent to light PAHs in quantitative analysis. Furthermore, the rapid and accurate GC-MS method coupled with 3D-IL@mGO MSPE procedure was successfully applied for the analysis of 16 PAHs in eleven vegetable oil samples from supermarket in Zhejiang Province. The results showed that the concentrations of BaP in 3 out of 11 samples were higher than the legal limit (2.0μg/kg, Commission Regulation 835/2011a), the sum of 8 heavy PAHs (BaA, CHR, BbF, BkF, BaP, IcP, DaA, BgP) in 11 samples was between 3.03μg/kg and 229.5μg/kg. Validation results on linearity, specificity, accuracy, precision and stability, as well as on application to the analysis of PAHs in oil samples demonstrated the applicability to food safety risk monitoring in China. Copyright © 2017 Elsevier B.V. All rights reserved.

Phase-field model of vapor-liquid-solid nanowire growth

Science.gov (United States)

Wang, Nan; Upmanyu, Moneesh; Karma, Alain

2018-03-01

We present a multiphase-field model to describe quantitatively nanowire growth by the vapor-liquid-solid (VLS) process. The free-energy functional of this model depends on three nonconserved order parameters that distinguish the vapor, liquid, and solid phases and describe the energetic properties of various interfaces, including arbitrary forms of anisotropic γ plots for the solid-vapor and solid-liquid interfaces. The evolution equations for those order parameters describe basic kinetic processes including the rapid (quasi-instantaneous) equilibration of the liquid catalyst to a droplet shape with constant mean curvature, the slow incorporation of growth atoms at the droplet surface, and crystallization within the droplet. The standard constraint that the sum of the phase fields equals unity and the conservation of the number of catalyst atoms, which relates the catalyst volume to the concentration of growth atoms inside the droplet, are handled via separate Lagrange multipliers. An analysis of the model is presented that rigorously maps the phase-field equations to a desired set of sharp-interface equations for the evolution of the phase boundaries under the constraint of force balance at three-phase junctions (triple points) given by the Young-Herring relation that includes torque term related to the anisotropy of the solid-liquid and solid-vapor interface excess free energies. Numerical examples of growth in two dimensions are presented for the simplest case of vanishing crystalline anisotropy and the more realistic case of a solid-liquid γ plot with cusped minima corresponding to two sets of (10 ) and (11 ) facets. The simulations reproduce many of the salient features of nanowire growth observed experimentally, including growth normal to the substrate with tapering of the side walls, transitions between different growth orientations, and crawling growth along the substrate. They also reproduce different observed relationships between the nanowire growth

Determination of submicrogram-per-liter concentrations of caffeine in surface water and groundwater samples by solid-phase extraction and liquid chromatography

Science.gov (United States)

Burkhardt, M.R.; Soliven, P.P.; Werner, S.L.; Vaught, D.G.

1999-01-01

A method for determining submicrogram-per-liter concentrations of caffeine in surface water and groundwater samples has been developed. Caffeine is extracted from a 1 L water sample with a 0.5 g graphitized carbon-based solid-phase cartridge, eluted with methylene chloride-methanol (80 + 20, v/v), and analyzed by liquid chromatography with photodiode-array detection. The single-operator method detection limit for organic-free water samples was 0.02 ??g/L. Mean recoveries and relative standard deviations were 93 ?? 13% for organicfree water samples fortified at 0.04 ??g/L and 84 ?? 4% for laboratory reagent spikes fortified at 0.5 ??g/L. Environmental concentrations of caffeine ranged from 0.003 to 1.44 ??g/L in surface water samples and from 0.01 to 0.08 ??g/L in groundwater samples.

Direct solid-phase microextraction combined with gas and liquid chromatography for the determination of lidocaine in human urine

NARCIS (Netherlands)

Koster, E.H M; Hofman, N.S K; de Jong, G.J.

Solid-phase microextraction (SPME) has been combined with gas chromatography (GC) and liquid chromatography (LC) for the determination of lidocaine in human urine. A polydimethylsiloxane (PDMS) coated fibre was directly immersed into buffered urine. Extraction conditions such as time, pH, ionic

Ergot alkaloids in rye flour determined by solid-phase cation-exchange and high-pressure liquid chromatography with fluorescence detection

DEFF Research Database (Denmark)

Storm, Ida Marie Lindhardt Drejer; Rasmussen, Peter Have; Strobel, B.W.

2008-01-01

Ergot alkaloids are mycotoxins that are undesirable contaminants of cereal products, particularly rye. A method was developed employing clean-up by cation-exchange solid-phase extraction, separation by high-performance liquid chromatography under alkaline conditions and fluorescence detection...

Magnetic solid phase extraction using ionic liquid-coated core-shell magnetic nanoparticles followed by high-performance liquid chromatography for determination of Rhodamine B in food samples.

Science.gov (United States)

Chen, Jieping; Zhu, Xiashi

2016-06-01

Three hydrophobic ionic liquids (ILs) (1-butyl-3-methylimidazole hexafluorophosphate ([BMIM]PF6), 1-hexyl-3-methyl-imidazole hexafluoro-phosphate ([HMIM]PF6), and 1-octyl-3-methylimidazole hexafluorophosphate ([OMIM]PF6)) were used to coat Fe3O4@SiO2 nanoparticles (NPs) with core-shell structures to prepare magnetic solid phase extraction (MSPE) agents (Fe3O4@SiO2@IL). A novel method of MSPE coupled with high-performance liquid chromatography for the separation/analysis of Rhodamine B was then established. The results showed that Rhodamine B was adsorbed rapidly on Fe3O4@SiO2@[OMIM]PF6 and was released using ethanol. Under optimal conditions, the pre-concentration factor for the proposed method was 25. The linear range, limit of detection (LOD), correlation coefficient (R), and relative standard deviation (RSD) were found to be 0.50-150.00 μgL(-1), 0.08 μgL(-1), 0.9999, and 0.51% (n=3, c=10.00 μgL(-1)), respectively. The Fe3O4@SiO2 NPs could be re-used up to 10 times. The method was successfully applied to the determination of Rhodamine B in food samples. Copyright © 2016. Published by Elsevier Ltd.

Muonium atoms in liquid and solid neopentane

International Nuclear Information System (INIS)

Ng, B.W.; Stadlbauer, J.M.; Jean, Y.C.; Walker, D.C.

1982-10-01

Relatively long-lived muonium atoms have been observed in neopentane (2,2-dimethylpropane). The yields of all muon states are found to be essentially the same in liquid and solid neopentane and the same as those in water. These results have bearings on three matters of current interest in muonium chemistry: the origin of the 'background' spin relaxation; the formation mechanisms; and the change in yields at the liquid-solid phase transition. These data were obtained by the μSR technique (muon spin rotation) at the TRIUMF accelerator

Determination of perfluorinated alkyl acids in corn, popcorn and popcorn bags before and after cooking by focused ultrasound solid-liquid extraction, liquid chromatography and quadrupole-time of flight mass spectrometry.

Science.gov (United States)

Moreta, Cristina; Tena, María Teresa

2014-08-15

An analytical method is proposed to determine ten perfluorinated alkyl acids (PFAAs) [nine perfluorocarboxylic acids (PFCAs) and perfluorooctane sulfonate (PFOS)] in corn, popcorn and microwave popcorn packaging by focused ultrasound solid-liquid extraction (FUSLE) and ultra high performance liquid chromatography (UHPLC) coupled to quadrupole-time of flight mass spectrometry (QTOF-MS/MS). Selected PFAAs were extracted efficiently in only one 10-s cycle by FUSLE, a simple, safe and inexpensive technique. The developed method was validated for microwave popcorn bags matrix as well as corn and popcorn matrices in terms of linearity, matrix effect error, detection and quantification limits, repeatability and recovery values. The method showed good accuracy with recovery values around 100% except for the lowest chain length PFAAs, satisfactory reproducibility with RSDs under 16%, and sensitivity with limits of detection in the order of hundreds picograms per gram of sample (between 0.2 and 0.7ng/g). This method was also applied to the analysis of six microwave popcorn bags and the popcorn inside before and after cooking. PFCAs contents between 3.50ng/g and 750ng/g were found in bags, being PFHxA (perfluorohexanoic acid) the most abundant of them. However, no PFAAs were detected either corn or popcorn, therefore no migration was assumed. Copyright © 2014 Elsevier B.V. All rights reserved.

Evaluation of Epicoccum nigrum for growth, morphology and production of natural colorants in liquid media and on a solid rice medium

DEFF Research Database (Denmark)

Mapari, Sameer Shamsuddin; Meyer, Anne S.; Thrane, Ulf

2008-01-01

in M1 medium (unoptimized) containing 5 g/l yeast autolysate. The color hue of the crude pigment extracts ranged from 74 to 102 exhibiting dark orange to green-yellow color. Pelleted morphology was shown to have a positive influence on the pigment production by E. nigrum strain IBT 41028 in the liquid...... genera preferred rice but E. nigrum produced 4.6 folds higher pigment in the liquid unoptimized fermentation medium compared to M. ruber. Solid phase extraction and subsequently HPLC-DAD analysis of the crude pigment extracts showed qualitative as well as quantitative variation in the pigment composition...

Selective solid-phase extraction based on molecularly imprinted technology for the simultaneous determination of 20 triazole pesticides in cucumber samples using high-performance liquid chromatography-tandem mass spectrometry.

Science.gov (United States)

Zhao, Fengnian; She, Yongxin; Zhang, Chao; Cao, Xiaolin; Wang, Shanshan; Zheng, Lufei; Jin, Maojun; Shao, Hua; Jin, Fen; Wang, Jing

2017-10-01

A selective analytical method for the simultaneous determination of 20 triazole fungicides and plant growth regulators in cucumber samples was developed using solid-phase extraction with specific molecularly imprinted polymers (MIPs) as adsorbents. The MIPs were successfully prepared by precipitation polymerization using triadimefon as the template molecule, methacrylic acid as the functional monomer, trimethylolpropane trimethacrylate as the crosslinker, and acetonitrile as the porogen. The performance and recognition mechanism for both the MIPs and non-molecularly imprinted polymers were evaluated using adsorption isotherms and adsorption kinetics. Liquid chromatography-tandem quadrupole mass spectrometry was used to identify and quantify the target analytes. The solid-phase extraction using the MIPs was rapid, convenient, and efficient for extraction and enrichment of the 20 triazole pesticides from cucumber samples. The recoveries obtained at three concentration levels (1, 2, and 10μgL -1 ) ranged from 82.3% to 117.6% with relative standard deviations of less than 11.8% (n=5) for all analytes. The limits of detection for the 20 triazole pesticides were all less than 0.4μgL -1 , and were sufficient to meet international standards. Copyright © 2017 Elsevier B.V. All rights reserved.

Taylor flow hydrodynamics in gas-liquid-solid micro reactors

NARCIS (Netherlands)

Warnier, M.J.F.

2009-01-01

Chemical reactions in which a gas phase component reacts with a liquid phase omponent at the surface of a solid catalyst are often encountered in chemical industry. The rate of such a gas-liquid-solid reaction is often limited by the mass transfer rate of the gas phase component, which depends on

Determination of perfluorinated carboxylic acids in fish fillet by micro-solid phase extraction, followed by liquid chromatography-triple quadrupole mass spectrometry.

Science.gov (United States)

Lashgari, Maryam; Lee, Hian Kee

2014-11-21

In the current study, a simple, fast and efficient combination of protein precipitation and micro-solid phase extraction (μ-SPE) followed by liquid chromatography-triple quadrupole tandem mass spectrometry (LC-MS/MS) was developed for the determination of perfluorinated carboxylic acids (PFCAs) in fish fillet. Ten PFCAs with different hydrocarbon chain lengths (C5-C14) were analysed simultaneously using this method. Protein precipitation by acetonitrile and μ-SPE by surfactant-incorporated ordered mesoporous silica were applied to the extraction and concentration of the PFCAs as well as for removal of interferences. Determination of the PFCAs was carried out by LC-MS/MS in negative electrospray ionization mode. MS/MS parameters were optimized for multiple reaction monitoring of the analytes. (13)C mass labelled PFOA as a stable-isotopic internal standard, was used for calibration. The detection limits of the method ranged from 0.97 ng/g to 2.7 ng/g, with a relative standard deviation of between 5.4 and 13.5. The recoveries were evaluated for each analyte and were ranged from 77% to 120%. The t-test at 95% confidence level showed that for all the analytes, the relative recoveries did not depend on their concentrations in the explored concentration range. The effect of the matrix on MS signals (suppression or enhancement) was also evaluated. Contamination at low levels was detected for some analytes in the fish samples. The protective role of the polypropylene membrane used in μ-SPE in the elimination of matrix effects was evaluated by parallel experiments in classical dispersive solid phase extraction. The results evidently showed that the polypropylene membrane was significantly effective in reducing matrix effects. Copyright © 2014 Elsevier B.V. All rights reserved.

Antifouling booster biocide extraction from marine sediments: a fast and simple method based on vortex-assisted matrix solid-phase extraction.

Science.gov (United States)

Caldas, Sergiane Souza; Soares, Bruno Meira; Abreu, Fiamma; Castro, Ítalo Braga; Fillmann, Gilberto; Primel, Ednei Gilberto

2018-03-01

This paper reports the development of an analytical method employing vortex-assisted matrix solid-phase dispersion (MSPD) for the extraction of diuron, Irgarol 1051, TCMTB (2-thiocyanomethylthiobenzothiazole), DCOIT (4,5-dichloro-2-n-octyl-3-(2H)-isothiazolin-3-one), and dichlofluanid from sediment samples. Separation and determination were performed by liquid chromatography tandem-mass spectrometry. Important MSPD parameters, such as sample mass, mass of C18, and type and volume of extraction solvent, were investigated by response surface methodology. Quantitative recoveries were obtained with 2.0 g of sediment sample, 0.25 g of C18 as the solid support, and 10 mL of methanol as the extraction solvent. The MSPD method was suitable for the extraction and determination of antifouling biocides in sediment samples, with recoveries between 61 and 103% and a relative standard deviation lower than 19%. Limits of quantification between 0.5 and 5 ng g -1 were obtained. Vortex-assisted MPSD was shown to be fast and easy to use, with the advantages of low cost and reduced solvent consumption compared to the commonly employed techniques for the extraction of booster biocides from sediment samples. Finally, the developed method was applied to real samples. Results revealed that the developed extraction method is effective and simple, thus allowing the determination of biocides in sediment samples.

Amino acids separation with the tetracarboxylic derived of the para-ter-butylcalix[4]arene by means of solid-liquid extraction assisted with lanthanides; Separacion de aminoacidos con el derivado tetracarboxilico del para-ter-butilcalix[4]areno mediante extraccion solido-liquido asistida con lantanidos

Energy Technology Data Exchange (ETDEWEB)

Bernal R, R. del C.

2014-07-01

The tetracarboxylic derived of the para-ter-butylcalix[4]arene (B{sub 4}ACEbL{sup 4}) does not exist commercially for what was synthesized and characterized at laboratory level. The separation of the L-tyrosine amino acid was studied by means of a solid-liquid extraction system with the B{sub 4}ACEbL{sup 4} as solid phase, in function of ph (2.5-7.5) and contact time (5 and 15 hours) to temperature of 15-17 grades C. Resulted that the ph and the contact time were decisive in the extraction percentage of water tyrosine. The lowest percentage was 49% to ph 4 and the highest percentage was 61% to ph 7.5 with 15 hours of contact. In a contact time of 5 hours the extraction was inferior to 32% (ph 4) and of 47% to ph 6.5. The europium effect (Eu (III)) was studied to ph acid in the tyrosine separation and was found that the tyrosine extraction is not increased neither decomposes in europium presence, this is simultaneously extracted by the calixarene but it does not enter in competition for the calixarene with the amino acid. The separate solid phases: calixarene-tyrosine was analyzed by Far infrared radiation (Fir), Mid-Infrared (Mir) spectroscopy and luminescence to check the tyrosine presence in the separate solids as well as the nature of the connection calixarene-tyrosine. In this way was possible to check the tyrosine presence and to propose the formed molecular species tyrosine-calixarene, those which interact mainly by means of hydrogen connections and Van der Waals forces. The liquid phases before and after the extraction were analyzed by UV-Vis spectrophotometry and luminescence. The Neutron activation analysis was used to determine the europium content in the solid and liquid phases of extractions in europium presence. The tyrosine degradation also shows dependence with the ph, obtaining 88% degradation to the 24 hours to ph 7.5, while to ph 3 is degraded the 54% of tyrosine present in the sample. The europium presence does not affect the tyrosine extraction

Magnetic solid-phase extraction of five pyrethroids from environmental water samples followed by ultrafast liquid chromatography analysis.

Science.gov (United States)

Yu, Xi; Sun, Ying; Jiang, Chunzhu; Sun, Xiumin; Gao, Yan; Wang, Yuanpeng; Zhang, Hanqi; Song, Daqian

2012-08-30

In this study, the polystyrene-coated magnetic nanoparticles (MNPs/PSt) were successfully prepared and characterized by Fourier transform infrared spectroscopy, transmission electron microscopy and vibrating sample magnetometry. The as-prepared MNPs/PSt were used as the adsorbent in magnetic solid phase extraction of five pyrethroids, including lambda-cyhalothrin, deltamethrin, esfenvalerate, permethrin, bifenthrin, in environmental water samples. The five pyrethroids were determined by ultra fast liquid chromatography-ultraviolet spectrometry. The influencing factors, including amount of MNPs/Pst, extraction time, pH value, type and volume of desorption solvent and desorption time, were examined and optimized. The extraction recoveries obtained with merely 50mg of MNPs/Pst were very satisfactory. The whole extraction process could be completed within 0.5h. The MNPs/PSt can be reused after an easy washing process. Thus, a simple, green, economical, time saving and effective method for pyrethroids analysis in environmental water samples was established. A high enrichment factor of 500 was achieved and the limits of detection for lambda-cyhalothrin, deltamethrin, esfenvalerate, permethrin, bifenthrin were 0.015±0.001 ng mL(-1), 0.012±0.001 ng mL(-1), 0.026±0.001 ng mL(-1), 0.020±0.001 ng mL(-1), 0.013±0.001 ng mL(-1), respectively. Recoveries obtained by analyzing spiked water samples at three concentration levels (0.100±0.001 ng mL(-1), 1.000±0.001 ng mL(-1), 10.000±0.001 ng mL(-1)) were between 78.97±8.38% and 96.05±8.38%. The standard curves for the five pyrethroids showed good linearity with the correlation coefficients in the range of 0.9994-0.9999. The intra-day and inter-day precision were satisfactory with the RSDs in the range of 2.05-5.52% and 2.73-8.38%, respectively. Copyright © 2012 Elsevier B.V. All rights reserved.

STM in liquids. A scanning tunneling microscopy exploration of the liquid-solid interface.

NARCIS (Netherlands)

Hulsken, B.

2008-01-01

This thesis reports of a series of atomic scale studies of the liquid-solid interface, carried out with a home-built liquid-cell Scanning Tunnelling Microscope (STM). The home-built liquid-cell STM is described in detail, and numerical simulations are performed to show that surfaces immersed in the

Solids recycling in solvent extraction

International Nuclear Information System (INIS)

Robinson, L.F.

1980-01-01

In an extraction process for extracting values from a first stream into a substantially immiscible second stream using a multi-compartmental rotary contactor, unwanted solids formed in the contactor and discharged at least partly with the the first stream are separated and re-entered into the contactor intermediate the points at which the streams are discharged. (author)

Sensitive determination of three aconitum alkaloids and their metabolites in human plasma by matrix solid-phase dispersion with vortex-assisted dispersive liquid-liquid microextraction and HPLC with diode array detection.

Science.gov (United States)

Wang, Xiaozhong; Li, Xuwen; Li, Lanjie; Li, Min; Liu, Ying; Wu, Qian; Li, Peng; Jin, Yongri

2016-05-01

A simple and sensitive method for determination of three aconitum alkaloids and their metabolites in human plasma was developed using matrix solid-phase dispersion combined with vortex-assisted dispersive liquid-liquid microextraction and high-performance liquid chromatography with diode array detection. The plasma sample was directly purified by matrix solid-phase dispersion and the eluate obtained was concentrated and further clarified by vortex-assisted dispersive liquid-liquid microextraction. Some important parameters affecting the extraction efficiency, such as type and amount of dispersing sorbent, type and volume of elution solvent, type and volume of extraction solvent, salt concentration as well as sample solution pH, were investigated in detail. Under optimal conditions, the proposed method has good repeatability and reproducibility with intraday and interday relative standard deviations lower than 5.44 and 5.75%, respectively. The recoveries of the aconitum alkaloids ranged from 73.81 to 101.82%, and the detection limits were achieved within the range of 1.6-2.1 ng/mL. The proposed method offered the advantages of good applicability, sensitivity, simplicity, and feasibility, which makes it suitable for the determination of trace amounts of aconitum alkaloids in human plasma samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Uranium Extraction From Artificial Liquid Waste Using Continuous Extraction Liquid membrane Technique

International Nuclear Information System (INIS)

Rusdianasari; Buchari

2002-01-01

The continuous extraction of uranium from artificial liquid waste by emulsion liquid membrane was carried out using one stage mixer-settler. This emulsion liquid membrane containing di-2-ethylhexylphosphoric acid (D2EHPA) and tri-n-buthyl phosphate (TBP) as carrier were carried out using one stage mixer-settler. The optimum condition gave the ratio of emulsion velocity to the feed velocity 1:4 and steady state reached after five minutes. The optimum condition was obtained at the 90.91 % of uranium recovered from raffinate, using EDTA as the masking agent with concentration 5x10 - 2 M . The total concentration of carrier was 3% with ratio D2EHPA and TBP 3:1. The emulsion liquid membrane has high relative selectivity after steady state with separation factors were α U , N i= 115,43 and α U , Fe 328,55. The result of experiment showed that emulsion liquid membrane containing D2EHPA and TBP as carrier have good performance for continuous system

SYNTHESE D’EXTRACTANTS ACIDES HEXADECYL- ET DECYLAMINOBIMETHYLENEDIPHOSPHONIQUES APPLICATION A L’EXTRACTION LIQUIDE-LIQUIDE DE Ni (II

Directory of Open Access Journals (Sweden)

M.A DIDI

2007-06-01

Après purification puis caractérisation des produits, nous avons réalisé divers tests d’extraction liquide - liquide de Ni (II en milieu sulfaté. Le temps d’équilibre déterminé par étude cinétique a été fixé à 40 minutes. Les paramètres changeant tels la température ( T = 20°C, 30°C et 50°C, le rapport du nombre de moles (n extractant / n métal (Q =1 à 6 et le rapport des volumes (Vaq / Vorg= 1, 2, 3 et 4 ont permis de maximiser le rendement d’extraction qui est de 46% avec le HABMP et de 44% pour le DADMP et ceci pour des extractions à un seul plateau.

Development of Extraction Methods for the Analysis of Perfluorinated Compounds in Leather with High Performance Liquid Chromatography Tandem Mass Spectrometry

Science.gov (United States)

Zhang, Yan; Wang, Youchao; Tang, Chuanjiang; Nie, Jingmei; Xu, Chengtao

2018-01-01

Perfluorinated compounds (PFCs), used to provide water, oil, grease, heat and stain repellency to a range of textile and other products, have been found to be persistent in the environment and are associated with adverse effects on humans and wildlife. This study presents the development and validation of an analytical method to determine the simultaneous presence of eleven PFCs in leather using solid-phase extraction followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The perfluorinated compounds were primarily extracted from the samples by a liquid extraction procedure by ultrasonic, in which the parameters were optimized. Then the solid-phase extraction (SPE) is the most important advantages of the developed methodology. The sample volume and elution conditions were optimized by means of an experimental design. The proposed method was applied to determine the PFCs in leather, where the detection limits of the eleven compounds were 0.09-0.96 ng/L, and the recoveries of all compounds spiked at 5 ng/L concentration level were in the range of 65-96%, with a better RSD lower than 19% (n = 7).

Solid radiation curable polyene compositions containing liquid polythiols and solid styrene-allyl copolymer based polyenes

International Nuclear Information System (INIS)

Morgan, C.R.

1977-01-01

Novel styrene-allyl alcohol copolymer based solid polyene compositions which when mixed with liquid polythiols can form solid curable polyene-polythiol systems are claimed. These solid polyenes, containing at least two reactive carbon-to-carbon unsaturated bonds, are urethane or ester derivatives of styrene-allyl alcohol copolymers. The solid polyenes are prepared by treating the hydroxyl groups of a styrene-allyl alcohol copolymer with a reactive unsaturated isocyanate, e.g., allyl isocyanate or a reactive unsaturated carboxylic acid, e.g., acrylic acid. Upon exposure to a free radical generator, e.g., actinic radiation, the solid polyene-polythiol compositions cure to solid, insoluble, chemically resistant, cross-linked polythioether products. Since the solid polyene-liquid polythiol composition can be cured in a solid state, such a curable system finds particular use in preparation of coatings, imaged surfaces such as photoresists, particularly solder-resistant photoresists, printing plates, etc

Ionic liquids used in extraction and separation of metal ions

International Nuclear Information System (INIS)

Shen Xinghai; Xu Chao; Liu Xinqi; Chu Taiwei

2006-01-01

Ionic liquids as green solvents now have become a research hotspot in the field of separation of metal ions by solvent extraction. Experimental results of extraction of various metal ions with ionic liquids as solvents, including that of alkali metals, alkaline earths, transition metals rare earths and actinides are introduced. The extraction of uranium, plutonium and fission products that are involved in spent nuclear fuel reprocessing is also reviewed. The possible extraction mechanisms are discussed. Finally, the prospect of replacement of volatile and/or toxic organic solvents with environmentally benign ionic liquids for solvent extraction and the potency of applications of ionic liquids in solvent extraction are also commented. (authors)

Finite size melting of spherical solid-liquid aluminium interfaces

DEFF Research Database (Denmark)

Chang, J.; Johnson, Erik; Sakai, T.

2009-01-01

We have investigated the melting of nano-sized cone shaped aluminium needles coated with amorphous carbon using transmission electron microscopy. The interface between solid and liquid aluminium was found to have spherical topology. For needles with fixed apex angle, the depressed melting tempera...... to the conclusion that the depressed melting temperature is not controlled solely by the inverse radius 1/R. Instead, we found a direct relation between the depressed melting temperature and the ratio between the solid-liquid interface area and the molten volume.......We have investigated the melting of nano-sized cone shaped aluminium needles coated with amorphous carbon using transmission electron microscopy. The interface between solid and liquid aluminium was found to have spherical topology. For needles with fixed apex angle, the depressed melting...

Novel thiosalicylate-based ionic liquids for heavy metal extractions

Energy Technology Data Exchange (ETDEWEB)

Leyma, Raphlin; Platzer, Sonja [Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, A-1090 Vienna (Austria); Jirsa, Franz [Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, A-1090 Vienna (Austria); Department of Zoology, University of Johannesburg, PO Box 524, Auckland Park, 2006, Johannesburg (South Africa); Kandioller, Wolfgang, E-mail: wolfgang.kandioller@univie.ac.at [Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, A-1090 Vienna (Austria); Krachler, Regina; Keppler, Bernhard K. [Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, A-1090 Vienna (Austria)

2016-08-15

Highlights: • Six thiosalicylate-based ammonium and phosphonium ionic liquids (ILs) were newly synthesized. • ILs showed good extraction of cadmium, copper, and zinc. • Phosphonium ILs showed better extraction efficiencies than their ammonium counterparts. - Abstract: This study aims to develop novel ammonium and phosphonium ionic liquids (ILs) with thiosalicylate (TS) derivatives as anions and evaluate their extracting efficiencies towards heavy metals in aqueous solutions. Six ILs were synthesized, characterized, and investigated for their extracting efficacies for cadmium, copper, and zinc. Liquid-liquid extractions of Cu, Zn, or Cd with ILs after 1–24 h using model solutions (pH 7; 0.1 M CaCl{sub 2}) were assessed using flame atomic absorption spectroscopy (F-AAS). Phosphonium-based ILs trihexyltetradecylphosphonium 2-(propylthio)benzoate [P{sub 66614}][PTB] and 2-(benzylthio)benzoate [P{sub 66614}][BTB] showed best extraction efficiency for copper and cadmium, respectively and zinc was extracted to a high degree by [P{sub 66614}][BTB] exclusively.

Solid-phase extraction and HPLC assay of nicotine and cotinine in plasma and brain.

Science.gov (United States)

Dawson, Ralph; Messina, S M; Stokes, C; Salyani, S; Alcalay, N; De Fiebre, N C; De Fiebre, C M

2002-01-01

The aim of this study was to develop a simple and reliable assay for nicotine (NIC) and its major metabolite, cotinine (COT), in plasma and brain. A method was developed that uses an extraction method compatible with reverse-phase high-performance liquid chromatography (HPLC) separation and ultraviolet (UV) detection. Sequential solid-phase extraction on silica columns followed by extraction using octadecyl (C18) columns resulted in mean percent recovery (n = 5) of 51 +/- 5, 64 +/- 10, and 52 +/- 10% for NIC, COT, and phenylimidazole (PI), respectively, in spiked 1-mL serum samples. Recovery (mean +/- SEM) of the internal standard (PI) from spiked samples of nicotine-injected rats averaged 64.1 +/- 1.5% (n = 138) from plasma, and 20.7+/-0.8% (n = 128) from brain. The limits of detection of NIC in plasma samples were approximately 8 ng per mL, and of COT, 13.6 ng per mL. Further optimization of our extraction method, using slower flow rates and solid-phase extraction on silica columns, followed by C18 column extraction, yielded somewhat better recoveries (38 +/-3%) for 1-mL brain homogenates. Interassay precision (coefficient of variation) was determined on the basis of daily calibrations for 2 months and was found to be 7%, 9%, and 9% for NIC, COT, and PI, respectively, whereas intra-assay variability was 3.9% for both NIC and COT. Limited studies were performed on analytical columns for comparison of retention, resolution, asymmetry, and column capacity. We concluded that a simple two-step solid-phase extraction method, coupled with HPLC separation and UV detection, can be used routinely to measure NIC and COT in biological fluids and tissues.

Nitrate conversion and supercritical fluid extraction of UO{sub 2}-CeO{sub 2} solid solution prepared by an electrolytic reduction-coprecipitation method

Energy Technology Data Exchange (ETDEWEB)

Zhu, L.Y. [Tsinghua Univ., Beijing (China). Inst. of Nuclear and New Energy Technology; China Institute of Atomic Energy, Beijing (China); Duan, W.H.; Wen, M.F.; Xu, J.M.; Zhu, Y.J. [Tsinghua Univ., Beijing (China). Inst. of Nuclear and New Energy Technology

2014-04-01

A low-waste technology for the reprocessing of spent nuclear fuel (SNF) has been developed recently, which involves the conversion of actinide and lanthanide oxides with liquid N{sub 2}O{sub 4} into their nitrates followed by supercritical fluid extraction of the nitrates. The possibility of the reprocessing of SNF from high-temperature gas-cooled reactors (HTGRs) with nitrate conversion and supercritical fluid extraction is a current area of research in China. Here, a UO{sub 2}-CeO{sub 2} solid solution was prepared as a surrogate for a UO{sub 2}-PuO{sub 2} solid solution, and the recovery of U and Ce from the UO{sub 2}-CeO{sub 2} solid solution with liquid N{sub 2}O{sub 4} and supercritical CO{sub 2} containing tri-n-butyl phosphate (TBP) was investigated. The UO{sub 2}-CeO{sub 2} solid solution prepared by electrolytic reduction-coprecipitation method had square plate microstructures. The solid solution after heat treatment was completely converted into nitrates with liquid N{sub 2}O{sub 4}. The XRD pattern of the nitrates was similar to that of UO{sub 2}(NO{sub 3}){sub 2} . 3H{sub 2}O. After 120 min of online extraction at 25 MPa and 50 , 99.98% of the U and 98.74% of the Ce were recovered from the nitrates with supercritical CO{sub 2} containing TBP. The results suggest a promising potential technology for the reprocessing of SNF from HTGRs. (orig.)

Silica Modified with Polyaniline as a Potential Sorbent for Matrix Solid Phase Dispersion (MSPD and Dispersive Solid Phase Extraction (d-SPE of Plant Samples

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Ireneusz Sowa

2018-03-01

Full Text Available Polyaniline (PANI is one of the best known conductive polymers with multiple applications. Recently, it was also used in separation techniques, mostly as a component of composites for solid-phase microextraction (SPME. In the present paper, sorbent obtained by in situ polymerization of aniline directly on silica gel particles (Si-PANI was used for dispersive solid phase extraction (d-SPE and matrix solid–phase extraction (MSPD. The efficiency of both techniques was evaluated with the use of high performance liquid chromatography with diode array detection (HPLC-DAD quantitative analysis. The quality of the sorbent was verified by Raman spectroscopy and microscopy combined with automated procedure using computer image analysis. For extraction experiments, triterpenes were chosen as model compounds. The optimal conditions were as follows: protonated Si-PANI impregnated with water, 160/1 sorbent/analyte ratio, 3 min of extraction time, 4 min of desorption time and methanolic solution of ammonia for elution of analytes. The proposed procedure was successfully used for pretreatment of plant samples.

Stable lithium electrodeposition in liquid and nanoporous solid electrolytes

KAUST Repository

Lu, Yingying; Tu, Zhengyuan; Archer, Lynden A.

2014-01-01

of these metals and their inability to form uniform electrodeposits on surfaces with inevitable defects. We report on electrodeposition of lithium in simple liquid electrolytes and in nanoporous solids infused with liquid electrolytes. We find that simple liquid

Alkylsulfate-based ionic liquids in the liquid–liquid extraction of aromatic hydrocarbons

International Nuclear Information System (INIS)

García, Silvia; Larriba, Marcos; García, Julián; Torrecilla, José S.; Rodríguez, Francisco

2012-01-01

Highlights: ► Values of α 2,1 for the four R-SO 4 ionic liquids are higher than those of sulfolane. ► Values of D 2 for all the ionic liquids are lower than those of sulfolane. ► Values of D 2 for [emim][C 2 H 5 SO 4 ] are the highest among the R-SO 4 ionic liquids. - Abstract: The (liquid + liquid) equilibrium data (LLE) for the extraction of toluene from heptane with different ionic liquids (ILs) based on the alkylsulfate anion (R-SO 4 ) was determined at T = 313.2 K and atmospheric pressure. The effect of more complex R-SO 4 anions on capacity of extraction and selectivity in the liquid–liquid extraction of toluene from heptane was studied. The ternary systems were formed by {heptane + toluene + 1,3-dimethylimidazolium methylsulfate ([mmim][CH 3 SO 4 ]), 1-ethyl-3-methylimidazolium hydrogensulfate ([emim][HSO 4 ]), 1-ethyl-3-methylimidazolium methylsulfate ([emim][CH 3 SO 4 ]), or 1-ethyl-3-methylimidazolium ethylsulfate ([emim][C 2 H 5 SO 4 ])}. The degree of quality of the experimental LLE data was ascertained by applying the Othmer–Tobias correlation. The phase diagrams for the ternary systems were plotted, and the tie lines correlated with the NRTL model compare satisfactorily with the experimental data.

Thermophysical measurements on solid and liquid rhenium

International Nuclear Information System (INIS)

Pottlacher, G.; Jager, H.; Neger, T.

1986-01-01

A fast resistive heating technique was used to measure such thermophysical data of solid and liquid rhenium as enthalpy, specific heat, thermal volume expansion, and electrical resistivity. The measurements are performed with heating rates of slightly more than 10 9 K s -1 up to states of superheated liquid rhenium (7500 K)

Liquid-like thermal conduction in intercalated layered crystalline solids

Science.gov (United States)

Li, B.; Wang, H.; Kawakita, Y.; Zhang, Q.; Feygenson, M.; Yu, H. L.; Wu, D.; Ohara, K.; Kikuchi, T.; Shibata, K.; Yamada, T.; Ning, X. K.; Chen, Y.; He, J. Q.; Vaknin, D.; Wu, R. Q.; Nakajima, K.; Kanatzidis, M. G.

2018-03-01

As a generic property, all substances transfer heat through microscopic collisions of constituent particles1. A solid conducts heat through both transverse and longitudinal acoustic phonons, but a liquid employs only longitudinal vibrations2,3. As a result, a solid is usually thermally more conductive than a liquid. In canonical viewpoints, such a difference also serves as the dynamic signature distinguishing a solid from a liquid. Here, we report liquid-like thermal conduction observed in the crystalline AgCrSe2. The transverse acoustic phonons are completely suppressed by the ultrafast dynamic disorder while the longitudinal acoustic phonons are strongly scattered but survive, and are thus responsible for the intrinsically ultralow thermal conductivity. This scenario is applicable to a wide variety of layered compounds with heavy intercalants in the van der Waals gaps, manifesting a broad implication on suppressing thermal conduction. These microscopic insights might reshape the fundamental understanding on thermal transport properties of matter and open up a general opportunity to optimize performances of thermoelectrics.

Molecular imprinting solid phase extraction for selective detection of methidathion in olive oil.

Science.gov (United States)

Bakas, Idriss; Oujji, Najwa Ben; Moczko, Ewa; Istamboulie, Georges; Piletsky, Sergey; Piletska, Elena; Ait-Ichou, Ihya; Ait-Addi, Elhabib; Noguer, Thierry; Rouillon, Régis

2012-07-13

A specific adsorbent for extraction of methidathion from olive oil was developed. The design of the molecularly imprinted polymer (MIP) was based on the results of the computational screening of the library of polymerisable functional monomers. MIP was prepared by thermal polymerisation using N,N'-methylene bisacrylamide (MBAA) as a functional monomer and ethylene glycol dimethacrylate (EGDMA) as a cross-linker. The polymers based on the itaconic acid (IA), methacrylic acid (MAA) and 2-(trifluoromethyl)acryl acid (TFMAA) functional monomers and one control polymer which was made without functional monomers with cross-linker EGDMA were also synthesised and tested. The performance of each polymer was compared using corresponding imprinting factor. As it was predicted by molecular modelling the best results were obtained for the MIP prepared with MBAA. The obtained MIP was optimised in solid-phase extraction coupled with high performance liquid chromatography (MISPE-HPLC-UV) and tested for the rapid screening of methidathion in olive oil. The proposed method allowed the efficient extraction of methidathion for concentrations ranging from 0.1 to 9 mg L(-1) (r(2)=0.996). The limits of detection (LOD) and quantification (LOQ) in olive oil were 0.02 mg L(-1) and 0.1 mg L(-1), respectively. MIPs extraction was much more effective than traditional C18 reverse-phase solid phase extraction. Copyright © 2012 Elsevier B.V. All rights reserved.

A novel dianionic amino acid ionic liquid-coated PEG 4000 modified Fe3O4 nanocomposite for the magnetic solid-phase extraction of trypsin.

Science.gov (United States)

Yang, Qin; Wang, Yuzhi; Zhang, Hongmei; Xu, Kaijia; Wei, Xiaoxiao; Xu, Panli; Zhou, Yigang

2017-11-01

A novel magnetic extractant, PEG 4000 modified Fe 3 O 4 nanomaterial that coated with dianionic amino acid ionic liquid (Fe 3 O 4 @PEG@DAAAIL), was successfully synthesized and characterized. X-ray diffraction (XRD), transmission electron microscope (TEM), vibrating sample magnetometer (VSM), fourier transform infrared spectrometry (FT-IR), thermal gravimetric analysis (TGA) and zeta potentials were used to confirm that the novel nanocomposite was successfully synthesized. Subsequently, the prepared Fe 3 O 4 @PEG@DAAAIL nanocomposite was used as the extractant for trypsin coupled with magnetic solid-phase extraction (MSPE). The concentrations of trypsin in the supernatant were detected by UV-vis spectrophotometer at 278nm. The extraction ability turned out to be better than the other four kinds of extractants prepared in this work. Furthermore, the influence of a series of factors, such as extraction time and temperature, initial trypsin concentration, the value of pH and ionic strength, was systematically investigated. Under the optimal extraction condition, the extraction capacity for trypsin could reach up to 718.73mg/g, absolutely higher than that of other adsorbents reported. This satisfactory extraction capacity could be maintained unchangeable after at least eight days, and kept over 90% of initial extraction capacity after eight recycles. What's more, the activity of trypsin after extraction retained 92.29% of initial activity, verifying the biocompatibility of the prepared extractant. Finally, the developed Fe 3 O 4 @PEG@DAAAIL-MSPE method was successfully applied to the real sample analysis with satisfactory results. All of above proves the potential value of Fe 3 O 4 @PEG@DAAAIL-MSPE in the analysis of biomass. Copyright © 2017 Elsevier B.V. All rights reserved.

Dynamics of solid nanoparticles near a liquid-liquid interface

Science.gov (United States)

Daher, Ali; Ammar, Amine; Hijazi, Abbas

2018-05-01

The liquid - liquid interface can be used as a suitable medium for generating some nanostructured films of metals, or inorganic materials such as semi conducting metals. This process can be controlled well if we study the dynamics of nanoparticles (NPs) at the liquid-liquid interface which is a new field of study, and is not understood well yet. The dynamics of NPs at liquid-liquid interfaces is investigated by solving the fluid-particle and particle-particle interactions. Our work is based on the Molecular Dynamics (MD) simulation in addition to Phase Field (PF) method. We modeled the liquid-liquid interface using the diffuse interface model, where the interface is considered to have a characteristic thickness. We have shown that the concentration gradient of one fluid in the other gives rise to a hydrodynamic force that drives the NPs to agglomerate at the interface. These obtained results may introduce new applications where certain interfaces can be considered to be suitable mediums for the synthesis of nanostructured materials. In addition, some liquid interfaces can play the role of effective filters for different species of biological NPs and solid state waste NPs, which will be very important in many industrial and biomedical domains.

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).

[Determination of 23 antibiotics and 3 β-agonists in livestock drinking water by ultra performance liquid chromatography-tandem mass spectrometry coupled with solid-phase extraction].

Science.gov (United States)

Shi, Ao

2016-02-01

A method has been developed for the simultaneous determination of 23 antibiotics (four categories) and 3 β-agonists in livestock drinking water using solid-phase extraction and ultra performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (UPLC-ESI MS/MS). The samples were adjusted pH to 5. 0, added Na2EDTA, enriched and cleaned-up by an HLB solid-phase extraction cartridge. The target compounds were confirmed and quantified by UPLC-ESI MS/MS with external standard method for the anti- biotics and internal standard method for the β-agonists. The recoveries were assessed by using lab tap water as matrix. The average recoveries of the 23 antibiotics and the 3 β-agonists were in the range of 50. 7%-104. 6% and the relative standard deviations (RSDs) were 2. 6%-8. 8% (n= 3). Under the optimal conditions, the calibration curves of the 23 antibiotics and the 3 β-agonists showed good linearity with the correlation coefficients better than 0. 994. The limits of detection (LODs, S/N≥3) ranged from 0. 01-0. 20 ng/L. The developed method was applied to analyze the livestock drinking waters in 36 Beijing intensive livestock farms. The results showed that some antibiotics were detected.

Optimization of hydrophilic interaction liquid chromatography/mass spectrometry and development of solid-phase extraction for the determination of paralytic shellfish poisoning toxins.

Science.gov (United States)

Turrell, Elizabeth; Stobo, Lesley; Lacaze, Jean-Pierre; Piletsky, Sergey; Piletska, Elena

2008-01-01

The combination of hydrophilic interaction liquid chromatography (HILIC) and liquid chromatography/mass spectrometry (LC/MS) for the determination of paralytic shellfish poisoning (PSP) toxins has been proposed for use in routine monitoring of shellfish. In this study, methods for the detection of multiple PSP toxins [saxitoxin (STX), neosaxitoxin (NEO), decarbamoyl saxitoxin (dcSTX), decarbamoyl neosaxitoxin (dcNEO), gonyautoxins 1-5 (GTX1, GTX2, GTX3, GTX4, GTX5), decarbamoyl gonyautoxins (dcGTX2 and dcGTX3), and the N-sulfocarbamoyl C toxins (C1 and C2)] were optimized using single (MS) and triple quadrupole (MS/MS) instruments. Chromatographic separation of the toxins was achieved by using a TSK-gel Amide-80 analytical column, although superior chromatography was observed through application of a ZIC-HILIC column. Preparative procedures used to clean up shellfish extracts and concentrate PSP toxins prior to analysis were investigated. The capacity of computationally designed polymeric (CDP) materials and HILIC solid-phase extraction (SPE) cartridges to retain highly polar PSP toxins was explored. Three CDP materials and 2 HILIC cartridges were assessed for the extraction of PSP toxins from aqueous solution. Screening of the CDPs showed that all tested polymers adsorbed PSP toxins. A variety of elution procedures were examined, with dilute 0.01% acetic acid providing optimum recovery from a CDP based on 2-(trifluoromethyl)acrylic acid as the monomer. ZIC-HILIC SPE cartridges were superior to the PolyLC equivalent, with recoveries ranging from 70 to 112% (ZIC-HILIC) and 0 to 90% (PolyLC) depending on the PSP toxin. It is proposed that optimized SPE and HILIC-MS methods can be applied for the quantitative determination of PSP toxins in shellfish.

Determination of Phthalate Plasticisers in Palm Oil Using Online Solid Phase Extraction-Liquid Chromatography (SPE-LC

Directory of Open Access Journals (Sweden)

Nazarudin Ibrahim

2014-01-01

Full Text Available Contamination of phthalates plasticisers to food has raised concern as some of the phthalates are suspected to be endocrine disruptors. The phthalates have high affinity with oily environment and analysing these chemicals in such matrices is difficult because of the trace amount of the analyte and interference from matrix. An online solid phase extraction (SPE technique using a large volume (3.5 mL injection was developed for the analysis of 6 common plasticisers in palm oil. A simple sample preparation involving alumina as a fat retainer and methanol : acetonitrile (1 : 1 as the extraction solvent was performed prior to the usage of online SPE-LC system. This system consists of two columns, C16 for the solid phase extraction (SPE and C18 as the analytical column, and a photo diode array detector. The calibration curves were linear from 5 to 1000 μg L−1, with correlation coefficients above 0.99. The instrumental limit of detection was 3 μg L−1 and satisfactory recovery was obtained. A screening on a few samples in the retail market revealed the presence of dibutyl phthalate (DBP and butylbenzylphthalate (BBP in the palm oil, with concentration less than 1 mg L−1.

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.

HPLC WITH SOLID PHASE EXTRACTION FOR IDENTIFICATION AND DIAGNOSIS OF ORGANOPHOSPHOROUS POISONING IN GOATS

Directory of Open Access Journals (Sweden)

S. Manna

2014-12-01

Full Text Available High performance liquid chromatographic determination of organophosphorous compound has been done by reverse phase chromatography in goats. The goats were dying showing the symptoms of organophosphorous poisoning. The viscera and stomach contents sample were received from Project Co-Ordinator, Animal Disease Research Institute, Phulnakhara, Cuttack, Orissa. The analysis of samples by HPLC with UV detector after cleaning up in Solid Phase Extraction (SPE revealed presence of malathion that was later quantified.

Fe3O4@ionic liquid@methyl orange nanoparticles as a novel nano-adsorbent for magnetic solid-phase extraction of polycyclic aromatic hydrocarbons in environmental water samples.

Science.gov (United States)

Liu, Xiaofei; Lu, Xin; Huang, Yong; Liu, Chengwei; Zhao, Shulin

2014-02-01

A novel nano-adsorbent, Fe3O4@ionic liquid@methyl orange nanoparticles (Fe3O4@IL@MO NPs), was prepared for magnetic solid-phase extraction (MSPE) of polycyclic aromatic hydrocarbons (PAHs) in environmental water samples. The Fe3O4@IL@MO NPs were synthesized by self-assembly of the ionic liquid 1-octadecyl-3-methylimidazolium bromide (C18mimBr) and methyl orange (MO) onto the surface of Fe3O4 silica magnetic nanoparticles, as confirmed by infrared spectroscopy, ultraviolet-visible spectroscopy and superconducting quantum interface device magnetometer. The extraction performance of Fe3O4@IL@MO NPs as a nano-adsorbent was evaluated by using five PAHs, fluorene (FLu), anthracene (AnT), pyrene (Pyr), benzo(a)anthracene (BaA) and benzo(a)pyrene (BaP) as model analytes. Under the optimum conditions, detection limits in the range of 0.1-2 ng/L were obtained by high performance liquid chromatography-fluorescence detection (HPLC-FLD). This method has been successfully applied for the determination of PAHs in environmental water samples by using the MSPE-HPLC-FLD. The recoveries for the five PAHs tested in spiked real water samples were in the range of 80.4-104.0% with relative standard deviations ranging from 2.3 to 4.9%. © 2013 Published by Elsevier B.V.

Supercooled and glassy water: Metastable liquid(s), amorphous solid(s), and a no-man's land

Science.gov (United States)

Handle, Philip H.; Loerting, Thomas; Sciortino, Francesco

2017-12-01

We review the recent research on supercooled and glassy water, focusing on the possible origins of its complex behavior. We stress the central role played by the strong directionality of the water-water interaction and by the competition between local energy, local entropy, and local density. In this context we discuss the phenomenon of polyamorphism (i.e., the existence of more than one disordered solid state), emphasizing both the role of the preparation protocols and the transformation between the different disordered ices. Finally, we present the ongoing debate on the possibility of linking polyamorphism with a liquid-liquid transition that could take place in the no-man's land, the temperature-pressure window in which homogeneous nucleation prevents the investigation of water in its metastable liquid form.

Numerical and experimental study of liquid breakup process in solid rocket motor nozzle

Science.gov (United States)

Yen, Yi-Hsin

Rocket propulsion is an important travel method for space exploration and national defense, rockets needs to be able to withstand wide range of operation environment and also stable and precise enough to carry sophisticated payload into orbit, those engineering requirement makes rocket becomes one of the state of the art industry. The rocket family have been classified into two major group of liquid and solid rocket based on the fuel phase of liquid or solid state. The solid rocket has the advantages of simple working mechanism, less maintenance and preparing procedure and higher storage safety, those characters of solid rocket make it becomes popular in aerospace industry. Aluminum based propellant is widely used in solid rocket motor (SRM) industry due to its avalibility, combusion performance and economical fuel option, however after aluminum react with oxidant of amonimum perchrate (AP), it will generate liquid phase alumina (Al2O3) as product in high temperature (2,700˜3,000 K) combustion chamber enviornment. The liquid phase alumina particles aggromorate inside combustion chamber into larger particle which becomes major erosion calprit on inner nozzle wall while alumina aggromorates impinge on the nozzle wall surface. The erosion mechanism result nozzle throat material removal, increase the performance optimized throat diameter and reduce nozzle exit to throat area ratio which leads to the reduction of exhaust gas velocity, Mach number and lower the propulsion thrust force. The approach to avoid particle erosion phenomenon taking place in SRM's nozzle is to reduce the alumina particle size inside combustion chamber which could be done by further breakup of the alumina droplet size in SRM's combustion chamber. The study of liquid breakup mechanism is an important means to smaller combustion chamber alumina droplet size and mitigate the erosion tack place on rocket nozzle region. In this study, a straight two phase air-water flow channel experiment is set up

Ultra-high performance liquid chromatography tandem mass spectrometry for the determination of five glycopeptide antibiotics in food and biological samples using solid-phase extraction.

Science.gov (United States)

Deng, Fenfang; Yu, Hong; Pan, Xinhong; Hu, Guoyuan; Wang, Qiqin; Peng, Rongfei; Tan, Lei; Yang, Zhicong

2018-02-23

This paper demonstrated the development and validation of an ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method for simultaneous determination of five glycopeptide antibiotics in food and biological samples. The target glycopeptide antibiotics were isolated from the samples by solvent extraction, and the extracts were cleaned with a tandem solid-phase extraction step using mixed strong cation exchange and hydrophilic/lipophilic balance cartridges. Subsequently, the analytes were eluted with different solvents, and then quantified by UHPLC-MS/MS in the positive ionization mode with multiple reaction monitoring. Under optimal conditions, good linear correlations were obtained for the five glycopeptide antibiotics in the concentration range of 1.0 μg/L to 20.0 μg/L, and with linear correlation coefficients >0.998. Employing this method, the target glycopeptide antibiotics in food and biological samples were identified with a recovery of 83.0-102%, and a low quantitation limit of 1.0 μg/kg in food and 2.0 μg/L in biological samples with low matrix effects. Copyright © 2018 Elsevier B.V. All rights reserved.

Simultaneous determination of sulfonamides, tetracyclines and tiamulin in swine wastewater by solid-phase extraction and liquid chromatography-mass spectrometry.

Science.gov (United States)

Ben, Weiwei; Qiang, Zhimin; Adams, Craig; Zhang, Heqing; Chen, Liping

2008-08-22

Little is known about the contamination level of antibiotics in swine wastewater in China. The highly complex matrix of swine wastewater, which generally has a chemical oxygen demand (COD) concentration as high as 15,000 mg/L, makes it difficult to detect antibiotics at trace levels. In this work, a highly selective and sensitive analytical method was developed for simultaneous determination of three classes of commonly used veterinary antibiotics including five sulfonamides, three tetracyclines and one macrolide in swine wastewater using solid-phase extraction (SPE) and liquid chromatography-mass spectrometry (LC-MS). The method detection limits (MDL) in the swine wastewater were determined to be between 5 and 91 ng/L, depending on specific antibiotics. Except sulfamethizole, all the other eight antibiotics were detected in the swine wastewaters collected from three concentrated swine feeding plants located in the Beijing (China) area, showing a concentration range of 0.62-32.67 microg/L. These results reveal the representative concentration levels of selected antibiotics in the swine wastewaters of Beijing area.

Pre-concentration of uranium from water samples by dispersive liquid-liquid micro-extraction

Energy Technology Data Exchange (ETDEWEB)

Khajeh, Mostafa; Nemch, Tabandeh Karimi [Zabol Univ. (Iran, Islamic Republic of). Dept. of Chemistry

2014-07-01

In this study, a simple and rapid dispersive liquid-liquid microextraction (DLLME) was developed for the determination of uranium in water samples prior to high performance liquid chromatography with diode array detection. 1-(2-pyridylazo)-2-naphthol (PAN) was used as complexing agent. The effect of various parameters on the extraction step including type and volume of extraction and dispersive solvents, pH of solution, concentration of PAN, extraction time, sample volume and ionic strength were studied and optimized. Under the optimum conditions, the limit of detection (LOD) and preconcentration factor were 0.3 μg L{sup -1} and 194, respectively. Furthermore, the relative standard deviation of the ten replicate was <2.6%. The developed procedure was then applied to the extraction and determination of uranium in the water samples.

Pre-concentration of uranium from water samples by dispersive liquid-liquid micro-extraction

International Nuclear Information System (INIS)

Khajeh, Mostafa; Nemch, Tabandeh Karimi

2014-01-01

In this study, a simple and rapid dispersive liquid-liquid microextraction (DLLME) was developed for the determination of uranium in water samples prior to high performance liquid chromatography with diode array detection. 1-(2-pyridylazo)-2-naphthol (PAN) was used as complexing agent. The effect of various parameters on the extraction step including type and volume of extraction and dispersive solvents, pH of solution, concentration of PAN, extraction time, sample volume and ionic strength were studied and optimized. Under the optimum conditions, the limit of detection (LOD) and preconcentration factor were 0.3 μg L -1 and 194, respectively. Furthermore, the relative standard deviation of the ten replicate was <2.6%. The developed procedure was then applied to the extraction and determination of uranium in the water samples.

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.

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

CONTRIBUTION TO THE DEVELOPMENT OF A SIMULATION SOFTWARE PERFORMANCE AND SHARING RATIO IN LIQUID-LIQUID EXTRACTION

Directory of Open Access Journals (Sweden)

A. Hadj Seyd

2015-07-01

Full Text Available The present work is to develop software to predict the value yield and the distribution coefficient in the process of liquid-liquid extraction of components of a mixture, from mathematical models expressing these entities, based on equations equilibrium between liquid-liquid phases, and predict the conditions under which the extraction operation is favorable, unfavorable or impossible to realize, by studying the variation of the entities cited, based on the parameters influencing the extraction, which are: initial concentrations, rate of solvent and pH, in the case of a simple extraction (extraction of neutral products or when it is reactive (extraction of complex acids or bases for one or more components.The programming language used is "Delphi" which is a very powerful oriented object programming under Windows.

Kinetics and reversibility of radiocaesium solid/liquid partitioning in sediments

International Nuclear Information System (INIS)

Comans, R.N.J.

1998-01-01

The kinetics and reversibility of radiocaesium solid/liquid partitioning in sediments have been reviewed and interpreted in terms of a mechanistic framework. This framework is based on the premise that radiocaesium is almost exclusively and highly-selectively bound to the frayed particle edges of illitic clay minerals in the sediments. Several processes with distinctly different rates can be distinguished in radiocaesium sorption to sediments. 2- and 3-box kinetic models can describe both the overall solid/liquid partitioning in sediments and the reversible (exchangeable) and irreversible (nonexchangeable or 'fixed') fractions of radiocaesium in sediments over time scales relevant for natural aquatic systems. The obtained rate parameters indicate that reversible partitioning of radiocaesium dominates over the first few days following a contamination event, whereas irreversible kinetics becomes important over time scales of weeks to months. The slow process, which reduces the exchangeability of sediment-bound radiocaesium over time, is believed to result from a migration of radiocaesium from exchangeable sites on the frayed edges of illite towards less-exchangeable interlayer sites. Long-term extraction of radiocaesium from historically contaminated sediments has given evidence for a reverse (remobilization) process with a half-life of the order of tens of years. These findings suggest that the long-term exchangeability of radiocaesium in sediments may be higher than the few % which is generally assumed. (orig.)

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.

Experimental design for reflection measurements of highly reactive liquid or solid substances with application to liquid sodium

International Nuclear Information System (INIS)

Chan, S.H.; Gossler, A.A.

1980-01-01

A versatile goniometer system with associated electronic components and mechanical instruments has been assembled. It is designed to measure spectral, specular reflectances of highly reactive liquid or solid substances over a spectral range of 0.3 to 9 μ and incidence angles of 12 to 30 0 off the normal direction. The capability of measuring reflectances of liquid substances clearly distinguishes this experimental design from conventional systems which are applicable only to solid substances. This design has been used to measure the spectral, specular reflectance of liquid sodium and preliminary results obtained are compared with those of solid sodium measured by other investigators

Solid and liquid radioactive waste treatment

International Nuclear Information System (INIS)

Rzyski, B.M.

1989-01-01

The technology for the treatment of low - and intermediate-level radioactive solid and liquid wastes is somewhat extensive. Some main guidance on the treatment methods are shown, based on informations contained in technical reports and complementary documents. (author) [pt

Trace hydrogen extraction from liquid lithium tin alloy

International Nuclear Information System (INIS)

Xie Bo; Hu Rui; Xie Shuxian; Weng Kuiping

2010-01-01

In order to finish the design of tritium extraction system (TES) of fusion fission hybrid reactor (FFHR) tritium blanket, involving the dynamic mathematical model of liquid metal in contact with a gaseous atmosphere, approximate mathematical equation of tritium in lithium tin alloy was deduced. Moreover, carrying process used for trace hydrogen extraction from liquid lithium tin alloy was investigated with hydrogen being used to simulate tritium in the study. The study results indicate that carrying process is effective way for hydrogen extraction from liquid lithium tin alloy, and the best flow velocity of carrier gas is about 4 L/min under 1 kg alloy temperatures and carrying numbers are the main influencing factors of hydrogen number. Hydrogen extraction efficiency can reach 85% while the alloy sample is treated 6 times at 823 K. (authors)

Microwave-assisted liquid-liquid microextraction based on solidification of ionic liquid for the determination of sulfonamides in environmental water samples.

Science.gov (United States)

Song, Ying; Wu, Lijie; Lu, Chunmei; Li, Na; Hu, Mingzhu; Wang, Ziming

2014-12-01

An easy, quick, and green method, microwave-assisted liquid-liquid microextraction based on solidification of ionic liquid, was first developed and applied to the extraction of sulfonamides in environmental water samples. 1-Ethy-3-methylimidazolium hexafluorophosphate, which is a solid-state ionic liquid at room temperature, was used as extraction solvent in the present method. After microwave irradiation for 90 s, the solid-state ionic liquid was melted into liquid phase and used to finish the extraction of the analytes. The ionic liquid and sample matrix can be separated by freezing and centrifuging. Several experimental parameters, including amount of extraction solvent, microwave power and irradiation time, pH of sample solution, and ionic strength, were investigated and optimized. Under the optimum experimental conditions, good linearity was observed in the range of 2.00-400.00 μg/L with the correlation coefficients ranging from 0.9995 to 0.9999. The limits of detection for sulfathiazole, sulfachlorpyridazine, sulfamethoxazole, and sulfaphenazole were 0.39, 0.33, 0.62, and 0.85 μg/L, respectively. When the present method was applied to the analysis of environmental water samples, the recoveries of the analytes ranged from 75.09 to 115.78% and relative standard deviations were lower than 11.89%. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of Organic Pollutants in Small Samples of Groundwaters by Liquid-Liquid Extraction and Capillary Gas Chromatography

DEFF Research Database (Denmark)

Harrison, I.; Leader, R.U.; Higgo, J.J.W.

1994-01-01

A method is presented for the determination of 22 organic compounds in polluted groundwaters. The method includes liquid-liquid extraction of the base/neutral organics from small, alkaline groundwater samples, followed by derivatisation and liquid-liquid extraction of phenolic compounds after neu...... neutralisation. The extracts were analysed by capillary gas chromatography. Dual detection by flame Ionisation and electron capture was used to reduce analysis time....

Liquid-liquid and liquid-solid phase separation and flocculation for a charged colloidal dispersion

International Nuclear Information System (INIS)

Lai, S.K.; Wu, K.L.

2002-01-01

We model the intercolloidal interaction by a hard-sphere Yukawa repulsion to which is added the long-range van der Waals attraction. In comparison with the Derjaguin-Landau-Verwey-Overbeek repulsion, the Yukawa repulsion explicitly incorporates the spatial correlations between colloids and small ions. As a result, the repulsive part can be expressed analytically and has a coupling strength depending on the colloidal volume fraction. By use of this two-body potential of mean force and in conjunction with a second-order thermodynamic perturbation theory, we construct the colloidal Helmholtz free energy and use it to calculate the thermodynamic quantities, pressure and chemical potential, needed in the determination of the liquid-liquid and liquid-solid phase diagrams. We examine, in an aqueous charged colloidal dispersion, the effects of the Hamaker constant and particle size on the conformation of a stable liquid-liquid phase transition calculated with respect to the liquid-solid coexistence phases. We find that there exists a threshold Hamaker constant or particle size whose value demarcates the stable liquid-liquid coexistence phases from their metastable counterparts. Applying the same technique and using the energetic criterion, we extend our calculations to study the flocculation phenomenon in aqueous charged colloids. Here, we pay due attention to determining the loci of a stability curve stipulated for a given temperature T 0 , and obtain the parametric phase diagram of the Hamaker constant vs the coupling strength or, at given surface potential, the particle size. By imposing T 0 to be the critical temperature T c , i.e., setting k B T 0 (=k B T c ) equal to a reasonable potential barrier, we arrive at the stability curve that marks the irreversible reversible phase transition. The interesting result is that there occurs a minimum size for the colloidal particles below (above) which the colloidal dispersion is driven to an irreversible (reversible) phase

Velocity of large bubble in liquid-solid mixture in a vertical tube

International Nuclear Information System (INIS)

Hamaguchi, H.; Sakaguchi, T.

1995-01-01

The upward movement of a large bubble in a stationary mixture of liquid and solid is one of the most fundamental phenomena of gas-liquid-solid three phase slug flow in a vertical tube. The purpose of this study is to make clear the characteristic of the rising velocity of this fundamental flow experimentally. The rising velocity of a large bubble V in a liquid-solid mixture was measured and compared with the velocity V o in a liquid (without solid). The experimental results were correlated using a non-dimensional velocity V * (=V/V o ), and the following results were obtained. It was found that the characteristic of the rising velocity differs according to the tube diameter and the liquid viscosity, or the Galileo number in the non-dimensional expression. It can be classified into two regimes. (i) When the liquid viscosity is large (or the tube diameter is small), V * decreases linearly against the volumetric solid fraction ε of the mixture. (ii) When the viscosity is small, on the other hand, the relation between V * and ε is not linear. This classification can be explained by the results in the previous papers by the authors dealing with a large bubble in a liquid

Velocity of large bubble in liquid-solid mixture in a vertical tube

Energy Technology Data Exchange (ETDEWEB)

Hamaguchi, H.; Sakaguchi, T. [Kobe Univ., Kobe (Japan)

1995-09-01

The upward movement of a large bubble in a stationary mixture of liquid and solid is one of the most fundamental phenomena of gas-liquid-solid three phase slug flow in a vertical tube. The purpose of this study is to make clear the characteristic of the rising velocity of this fundamental flow experimentally. The rising velocity of a large bubble V in a liquid-solid mixture was measured and compared with the velocity V{sub o} in a liquid (without solid). The experimental results were correlated using a non-dimensional velocity V{sup *}(=V/V{sub o}), and the following results were obtained. It was found that the characteristic of the rising velocity differs according to the tube diameter and the liquid viscosity, or the Galileo number in the non-dimensional expression. It can be classified into two regimes. (i) When the liquid viscosity is large (or the tube diameter is small), V{sup *} decreases linearly against the volumetric solid fraction {epsilon} of the mixture. (ii) When the viscosity is small, on the other hand, the relation between V{sup *} and {epsilon} is not linear. This classification can be explained by the results in the previous papers by the authors dealing with a large bubble in a liquid.

Determination of six polyether antibiotic residues in foods of animal origin by solid phase extraction combined with liquid chromatography-tandem mass spectrometry.

Science.gov (United States)

Ha, Jing; Song, Ge; Ai, Lian-Feng; Li, Jian-Chen

2016-04-01

A new method using solid phase extraction (SPE) combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed for the determination of six polyether antibiotics, including lasalocid, salinomycin, monensin, narasin, madubamycin and nigericin residues, in foods of animal origin. The samples were extracted with acetonitrile and purified by ENVI-Carb SPE columns after comparing the impurity effect and maneuverability of several SPE cartridges. Subsequently, the analytes were separated on a Hypersil Gold column (2.1×150mm, 5μm) and analyzed by MS/MS detection. The limit of quantization (LOQ) for milk and chicken was 0.4μg/kg, and for chicken livers and eggs, it was 1μg/kg. The linearity was satisfactory with a correlation coefficient of >0.9995 at concentrations ranging from 2 to 100μg/L. The average recoveries of the analytes fortified at three levels ranged from 68.2 to 114.3%, and the relative standard deviations ranged from 4.5 to 12.1%. The method was suitable for quantitative analysis and confirmation of polyether antibiotic residues in foods of animal origin. Copyright © 2016 Elsevier B.V. All rights reserved.

Isolation and Purification of Unstable Iridoid Glucosides from Traditional Chinese Medicine by Preparative High Performance Liquid Chromatography Coupled with Solid-phase Extraction

Institute of Scientific and Technical Information of China (English)

无

2011-01-01

An efficient preparative method was successfully developed for isolation and purification of unstable components from medicinal plant extracts, using a combined method of preparative high performance liquid chro-matography（HPLC） and solid-phase extraction（SPE）. The aim of this study was to obtain an effective method with high preparative efficiency and importantly to avoid the transformation of unstable compounds. The preparative HPLC system was based on an LC/MS controlled four-channel autopurification system. The SPE method was performed with a C18 packing material to trap the target compounds and to remove the acidic additive derived from the mobile phase. Using this method, the unstable iridoid glucosides（IGs） as model compounds were successfully isolated and purified from the extract of Hedyotis diffusa Willd. Six IGs（including one new minor IG） and one nucleotide compound were simultaneously obtained, each with a purity of 〉91% as determined by HPLC. The structures of the isolated compounds were identified by UPLC/Q-TOF MS, UV, 1D and/or 2D NMR. It was demonstrated that the combination of preparative HPLC with SPE is a versatile tool for preparative purification of unstable compounds from complex natural products.

Separation and determination of citrinin in corn using HPLC fluorescence detection assisted by molecularly imprinted solid phase extraction clean-up

Science.gov (United States)

A liquid chromatography based method to detect citrinin in corn was developed using molecularly imprinted solid phase extraction (MISPE) sample clean-up. Molecularly imprinted polymers were synthesized using 1,4-dihydroxy-2-naphthoic acid as the template and an amine functional monomer. Density func...

Solid-Liquid and Liquid-Liquid Equilibrium in the Ternary System Acetic Acid-Propanoic Acid-Formamide.

Czech Academy of Sciences Publication Activity Database

Sedláková, Zuzana; Malijevská, I.

2007-01-01

Roč. 261, 1-2 (2007) , s. 129-132 ISSN 0378-3812. [International Conference on Properties and Phase Equilibria for Product and Process Design PPEPPD 2007 /11./. Hersonissos, Crete, 20.05.2007-25.05.2007] Institutional research plan: CEZ:AV0Z40720504 Keywords : solid-liquid equilibrium * ternary system * solid adduct Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.506, year: 2007

Association of solvent extraction and liquid-liquid flotation processes for metal recovery

International Nuclear Information System (INIS)

Puget, Flavia P.; Mendonca, Luciano A. de; Massarani, Giulio

2000-01-01

From the batch solvent extraction process, in this work it has been carried out a preliminary study aiming the determination of the optimal operating conditions for zirconium recovery (10 ppm) using alamine 336 (tricaprylylamine) as extractor. The results have shown that the extraction takes place instantaneously (5s of manual agitation) and that at pH around 2.0 the extraction efficiency is up to 98-99% for an aqueous/organic phase volumetric ratio of 10. Based on these results, it is proposed to evaluate the possibility of using of a pioneering technology for metal recovery at low concentrations, using a experimental set-up that associates standard solvent extraction process with liquid-liquid flotation process. (author)

Combustion chamber for solid and liquid waste

Energy Technology Data Exchange (ETDEWEB)

Vcelak, L.; Kocica, J.; Trnobransky, K.; Hrubes, J. (VSCHT, Prague (Czechoslovakia))

1989-04-01

Describes combustion chamber incorporated in a new boiler manufactured by Elitex of Kdyne to burn waste products and occasionally liquid and solid waste from neighboring industries. It can handle all kinds of solids (paper, plastics, textiles, rubber, household waste) and liquids (volatile and non-volatile, zinc, chromium, etc.) and uses coal as a fuel additive. Its heat output is 3 MW, it can burn 1220 kg/h of coal (without waste, calorific value 11.76 MJ/kg) or 500 kg/h of coal (as fuel additive, calorific value 11.76 MJ/kg) or 285 kg/h of solid waste (calorific value 20.8 MJ/kg). Efficiency is 75%, capacity is 103 m{sup 3} and flame temperature is 1,310 C. Individual components are designed for manufacture in small engineering workshops with basic equipment. A disk absorber with alkaline filling is fitted for removal of harmful substances arising when PVC or tires are combusted.

Gastric emptying of solids and liquids in obesity.

Science.gov (United States)

Glasbrenner, B; Pieramico, O; Brecht-Krauss, D; Baur, M; Malfertheiner, P

1993-07-01

The purpose of this study was to determine whether obese patients have different rates of solid and liquid gastric emptying compared to healthy controls. Twenty-four obese patients (7 males, 17 females) were investigated prior to dietary restriction. The patients had a weight excess above ideal weight ranging from 25% to 216% (mean weight 118.1 +/- 6.5 kg). The control group consisted of 8 healthy subjects (4 males, 4 females), within 10% of the ideal weight. The solid phase of the test meal consisted of 40 g bread, 30 g ham, 10 g margarine, and two scrambled eggs labeled with 99mTc. For the liquid phase, 200 ml orange juice was labeled with 201Tl. Three-minute counts of both tracers were taken for 106 min using a large field-of-view gamma camera. In obese patients, a significantly shortened lag phase for the emptying of solids was observed (27.0 +/- 3.3 versus 38.4 +/- 4.1 min; P < 0.05). Half-emptying time (105.9 +/- 6.7 versus 100.7 +/- 5.7 min), emptying rate (0.60 +/- 0.04 versus 0.71 +/- 0.07%/min), and total emptying of solids (49.4 +/- 3.6 versus 50.5 +/- 5.0%) were not different from controls. Obese subjects had a trend to slowed liquid emptying (half-time 82.7 +/- 4.8 versus 69.9 +/- 6.9 min; emptying rate 0.59 +/- 0.03 versus 0.65 +/- 0.03%/min; total emptying 59.8 +/- 2.9 versus 66.0 +/- 3.3%), but this was not statistically significant. There was no correlation between weight or body surface area and rate of solid or liquid gastric emptying.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of a contact device type ejector system for liquid-liquid extraction

International Nuclear Information System (INIS)

Schwamback, Niomedes

2002-04-01

The objective of the present work was to evaluate an ejector system, operated simultaneously with two immiscible liquid phases and a gas phase, as a contact device for liquid-liquid extraction processes. The ejector, made of perspex, has a variable geometry, although this feature was not explored in the thesis. Motivated by recent uses of liquid-liquid extraction processes for the removal of traces of heavy metal from waste waters, it was decided to carry out tests with synthetic effluents. This strategy, typical of experimental work under evaluation of technical feasibility, greatly simplifies experiments, since the nature of the chemical species involved and their feed concentrations are known exactly and do not fluctuate. The extractant used was DEHPA (diethyl hexyl phosphoric acid). The metal chosen for tests was iron with oxidation number +3, because of its high extraction coefficient towards DEHPA and also for its chemical behavior similar to americium and other heavy metals. In addition to that, iron forms soluble coloured complexes adequate to spectrophotometric determination analysis, a simple, quick and very reliable analytical technique. The effects of electrolytes of interest, namely NaCl, FeSO 4 and Al(NO 3 ) 3 , upon the extraction process were investigated. The effects resulting from the introduction of a gas phase, actually air (bubbles), in the ejector upon the extraction efficiency were studied. By coupling advanced digital photographic technique and image analysis with microcomputer, the bubble mean size was measured. It was then correlated with equipment's geometrical (characteristic diameters) and operational variables (phases' flow rates and gas hold-ups). To enable scale-up procedures, data were preferably correlated by means of dimensionless groups. For the systems and conditions investigated in this thesis and under the same operational conditions, the introduction of air bubbles by means of an ejector has greatly improved the process

Comparison between liquid and solid tunable focus lenses

International Nuclear Information System (INIS)

Santiago-Alvarado, A; Cruz-Martinez, V M; Vazquez-Montiel, S; Munoz-Lopez, J; Diaz-Gonzalez, G; Campos-Garcia, M

2011-01-01

Nowadays more reports in the use of tunable lenses are reported, it is due to the benefits they offer in optical systems design. A tunable lens is an optical system that can focus on a range of positions by changing dynamically one of its geometric parameters. There are several types of tunable lenses, the most known types are the liquid, the solid elastic, with variable refractive index, and lenses that use a dielectric medium. This paper presents the analysis and opto-mechanical design of two tunable lenses, a liquid lens and another Solid Elastic Lens (SEL). Both lenses are made in mounting aluminium and polydimethylsiloxane (PDMS) as refractor medium, the liquid lens use two elastic membranes containing a liquid medium between them while the SEL only use PDMS material as body of the lens (medium refractor). We describe the opto-mechanical performance of both types of lens highlighting the main features of each. Finally, results of a opto-functional comparison between these prototypes are showed.

The influence of a solid and liquid bolus on food-stimulated gastroesophageal reflux

International Nuclear Information System (INIS)

Naeser, A.; Behrens, J.K.; Vejen-Christiansen, L.; Funch-Jensen, P.; Thommesen, P.; Aarhus Kommunehospital

1992-01-01

Using a radiological method to demonstrate food-stimulated gastroesophageal reflux (GER), a comparative study was carried out employing a solid, already validated bolus versus a liquid one. One hundred and four consecutive patients received both a solid and a liquid bolus in randomized order. GER was observed in 37 (35.6%) patients receiving the solid bolus versus 28 (26.9%) with the liquid one. This means that the solid bolus provokes significantly more reflux (P [de

Effect of bile diversion on satiety and fat absorption from liquid and solid dietary sources

International Nuclear Information System (INIS)

Doty, J.E.; Gu, Y.G.; Meyer, J.H.

1988-01-01

In previous studies, liquid fat has been used to determine the effect of bile diversion on fat absorption. Since protein digests, in addition to bile salts, are capable of solubilizing lipids, we hypothesized that fat incorporated in the protein-rich matrix of solid food would be less sensitive to bile diversion than fat ingested as an oil or liquid. Using [3H]glycerol triether as a nonabsorbable fat recovery marker, we determined how much [14C]triolein was absorbed from solid (chicken liver) and liquid (margarine) dietary sources. After a standard liquid/solid meal with either the chicken liver or margarine labeled, midintestinal chyme was collected for 6 hr, extracted, and counted for 14C and 3H activity. Zero, eighty, or one hundred percent of endogenous bile was diverted. Fat absorption from both chicken liver and margarine was nearly complete by midintestine with 0% diversion and was little affected by diversion of 80% of bile. Complete biliary diversion significantly decreased fat absorption from margarine (87.9 +/- 4.4 to 37.2 +/- 9.2%, P less than 0.05) but reduced [14C]triolein absorption from chicken liver less consistently and insignificantly (78.8 +/- 6.9 to 43.9 +/- 10.6%). These data indicate that fat absorption is not solely dependent on bile and support the hypothesis that fat ingested in a cellular matrix is less dependent on bile than liquid fat. Using these same animals but with the midintestinal cannulas plugged to expose the distal intestine to unabsorbed luminal nutrients, we also demonstrated that bile diversion of an initial meal reduced food consumption at a meal offered 3 hr later

A twin purification/enrichment procedure based on two versatile solid/liquid extracting agents for efficient uptake of ultra-trace levels of lorazepam and clonazepam from complex bio-matrices.

Science.gov (United States)

Hemmati, Maryam; Rajabi, Maryam; Asghari, Alireza

2017-11-17

In this research work, two consecutive dispersive solid/liquid phase microextractions based on efficient extraction media were developed for the influential and clean pre-concentration of clonazepam and lorazepam from complicated bio-samples. The magnetism nature of the proposed nanoadsorbent proceeded the clean-up step conveniently and swiftly (∼5min), pursued by a further enrichment via a highly effective and rapid emulsification microextraction process (∼4min) based on a deep eutectic solvent (DES). Finally, the instrumental analysis step was practicable via high performance liquid chromatography-ultraviolet detection. The solid phase used was an adequate magnetic nanocomposite termed as polythiophene-sodium dodecyl benzene sulfonate/iron oxide (PTh-DBSNa/Fe 3 O 4 ), easily and cost-effectively prepared by the impressive co-precipitation method followed by the efficient in situ sonochemical oxidative polymerization approach. The identification techniques viz. FESEM, XRD, and EDX certified the supreme physico-chemical properties of this effective nanosorbent. Also the powerful liquid extraction agent, DES, based on bio-degradable choline chloride, possessed a high efficiency, tolerable safety, low cost, and facile and mild synthesis route. The parameters involved in this versatile hyphenated procedure, efficiently evaluated via the central composite design (CCD), showed that the best extraction conditions consisted of an initial pH value of 7.2, 17mg of the PTh-DBSNa/Fe 3 O 4 nanocomposite, 20 air-agitation cycles (first step), 245μL of methanol, 250μL of DES, 440μL of THF, and 8 air-agitation cycles (second step). Under the optimal conditions, the understudied drugs could be accurately determined in the wide linear dynamic ranges (LDRs) of 4.0-3000ngmL -1 and 2.0-2000ngmL -1 for clonazepam and lorazepam, respectively, with low limits of detection (LODs) ranged from 0.7 to 1.0ngmL -1 . The enrichment factor (EF) and percentage extraction recovery (%ER

Recycling of Metal Containing Waste by Liquid-Liquid Extraction

International Nuclear Information System (INIS)

Reinhardt, H.

1999-01-01

Through the years, a large number of liquid-liquid extraction have been proposed for metal waste recovery and recycling(1,2). However, few of them have achieved commercial application. In fact, relatively little information is available on practical operation and economic feasibility. This presentation will give complementary information by describing and comparing three processes, based on the Am MAR hydrometallurgical concept and representing three different modes of operation

Anaerobic treatment of solid and liquid residues. Papers

International Nuclear Information System (INIS)

Maerkl, H.; Stegmann, R.

1994-01-01

Anaerobic processes are getting increasing attention in the disposal of liquid waste of the food industry and chemical industry and solid organic residues of the municipal sector. The main advantages of anaerobic processes are the favourable energy balance and the comparatively small volume of new biomass produced. There are new satisfactory technical solutions for nearly all problems encountered in practice. A conference on ''Anaerobic treatment of solid and liquid residues'' was held on 2-4 November 1994. The state of the art and new developments were presented in lectures by experts from research and practice. (orig.) [de

Biredox ionic liquids with solid-like redox density in the liquid state for high-energy supercapacitors.

Science.gov (United States)

Mourad, Eléonore; Coustan, Laura; Lannelongue, Pierre; Zigah, Dodzi; Mehdi, Ahmad; Vioux, André; Freunberger, Stefan A; Favier, Frédéric; Fontaine, Olivier

2017-04-01

Kinetics of electrochemical reactions are several orders of magnitude slower in solids than in liquids as a result of the much lower ion diffusivity. Yet, the solid state maximizes the density of redox species, which is at least two orders of magnitude lower in liquids because of solubility limitations. With regard to electrochemical energy storage devices, this leads to high-energy batteries with limited power and high-power supercapacitors with a well-known energy deficiency. For such devices the ideal system should endow the liquid state with a density of redox species close to the solid state. Here we report an approach based on biredox ionic liquids to achieve bulk-like redox density at liquid-like fast kinetics. The cation and anion of these biredox ionic liquids bear moieties that undergo very fast reversible redox reactions. As a first demonstration of their potential for high-capacity/high-rate charge storage, we used them in redox supercapacitors. These ionic liquids are able to decouple charge storage from an ion-accessible electrode surface, by storing significant charge in the pores of the electrodes, to minimize self-discharge and leakage current as a result of retaining the redox species in the pores, and to raise working voltage due to their wide electrochemical window.

Methodology for the determination of residues of organophosphorous pesticides in milk of domestic consumption by means of gas chromatography and extraction in solid phase

International Nuclear Information System (INIS)

Romero Blanco, Eric; Meza Nunez, Humberto; Poveda Calvo, Vanessa

2005-01-01

A new method oriented to the detection and quantification of 15 organophosphate pesticide in raw milk samples for national consumption has been developed by using a gas chromatograph equipped with polydimethylsiloxane capillary column and a nitrogen-phosphorus detector (NPD), in combination with the extraction technique in solid phase (SPE) for the sample cleaning process and pesticide extraction. Recovery percentages obtained were close to 100% and the detection limits obtained were lower than 20 μg/L for 13 of the organophosphates analyzed. Overall, the method showed important improvement as compared to conventional liquid/liquid extraction methodologies. (Author) [es

Extraction of triazole fungicides in environmental waters utilizing poly (ionic liquid)-functionalized magnetic adsorbent.

Science.gov (United States)

Liu, Cheng; Liao, Yingmin; Huang, Xiaojia

2017-11-17

This work prepared a new poly (ionic liquid)-functionalized magnetic adsorbent (PFMA) for the extraction of triazole fungicides (TFs) in environmental waters prior to determination by high performance liquid chromatography/diode array detection (HPLC-DAD). A polymerizable ionic liquid, 1-methyl-3-allylimidazolium bis(trifluoromethylsulfonyl)imide was employed to copolymerize with divinylbenzene on the surface of modified magnetite to fabricate the PFMA. The morphology, spectroscopic and magnetic properties of the new adsorbent were investigated by different techniques. A series of key parameters that influence the extraction performance including the amount of PFMA, desorption solvent, adsorption and desorption time, sample pH value and ionic strength were optimized in detail. Under the optimum conditions, the prepared PFMA could extract targeted TFs effectively and quickly under the format of magnetic solid-phase extraction (MSPE). Satisfactory linearities were achieved in the range of 0.1-200.0μg/L for triadimenol and 0.05-200.0μg/L for other TFs with good coefficients of determination above 0.99 for all analytes. The limits of detection (S/N=3) and limits of quantification (S/N=10) for TFs were in the range of 0.0050-0.0078μg/L and 0.017-0.026μg/L, respectively. Environmental waters including lake, river and well waters were used to demonstrate the applicability of developed MSPE-HPLC-DAD method, and satisfactory recoveries and repeatability were obtained. Copyright © 2017 Elsevier B.V. All rights reserved.

Determination of neonicotinoid pesticides residues in agricultural samples by solid-phase extraction combined with liquid chromatography-tandem mass spectrometry.

Science.gov (United States)

Xie, Wen; Han, Chao; Qian, Yan; Ding, Huiying; Chen, Xiaomei; Xi, Junyang

2011-07-15

This work reports a new sensitive multi-residue liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for detection, confirmation and quantification of six neonicotinoid pesticides (dinotefuran, thiamethoxam, clothiandin, imidacloprid, acetamiprid and thiacloprid) in agricultural samples (chestnut, shallot, ginger and tea). Activated carbon and HLB solid-phase extraction cartridges were used for cleaning up the extracts. Analysis is performed by LC-MS/MS operated in the multiple reaction monitoring (MRM) mode, acquiring two specific precursor-product ion transitions per target compound. Quantification was carried by the internal standard method with D(4)-labeled imidacloprid. The method showed excellent linearity (R(2)≥0.9991) and precision (relative standard deviation, RSD≤8.6%) for all compounds. Limits of quantification (LOQs) were 0.01 mg kg(-1) for chestnut, shallot, ginger sample and 0.02 mg kg(-1) for tea sample. The average recoveries, measured at three concentrations levels (0.01 mg kg(-1), 0.02 mg kg(-1) and 0.1 mg kg(-1) for chestnut, shallot, ginger sample, 0.02 mg kg(-1), 0.04 mg kg(-1) and 0.2 mg kg(-1) for tea sample), were in the range 82.1-108.5%. The method was satisfactorily validated for the analysis of 150 agricultural samples (chestnut, shallot, ginger and tea). Imidacloprid and acetamiprid were detected at concentration levels ranging from 0.05 to 3.6 mg kg(-1). Copyright © 2011 Elsevier B.V. All rights reserved.

Rapid method for determination of glyphosate in groundwater using high performance liquid chromatography and solid-phase extraction after derivatization

Directory of Open Access Journals (Sweden)

Valdir Eduardo Olivo

2015-04-01

Full Text Available The intensive use of pesticides in agriculture has prompted researchers to develop new methods for identifying these pollutants in water. This study sought to validate a high performance liquid chromatography (HPLC method to determine the concentration of the pesticide glyphosate in groundwater samples by using solid-phase extraction (SPE filters after derivatization with chloroformate 9-fluorenylmethoxycarbonyl (FMOC-Cl. For the HPLC method, we evaluated the following main validation parameters: linearity, specificity, precision, accuracy, robustness, and limits of detection and quantification. After validation of the method, we determined the concentration of glyphosate in samples from thirteen deep, tubular wells distributed in urban and rural areas in Chapecó, SC, Brazil. The solvent used in the extraction of excess FMOC-Cl was dichloromethane and subsequently filtration was performed on C18 SPE, and injected into the chromatograph column in amino polymer with fluorescence detection. The analytical curve made in ultrapure water was linear, with a correlation coefficient of 0.99. The limits of detection and quantification were 0.24 and 0.07 µg L-1, respectively. Recovery tests in natural waters ranged from 90.37 to 101.70%. Glyphosate was detected in 5 of the thirteen wells evaluated. The highest concentration of glyphosate (6.80 µg L-1 was detected in a countryside well, near the municipal water supply. Despite the low levels of glyphosate detected in our study, any amount present in groundwater samples is worrisome, as these molecules have low ground mobility.

Enhanced flavour extraction in continuous liquid-liquid extractors

CSIR Research Space (South Africa)

Apps, P

2005-08-12

Full Text Available stirrer that prevents channelling improves extraction efficiency by between 2.8 and 17.6 times. Use of the stir bar extends the application of CLLE to samples that are not free-running liquids, thereby reducing sample manipulations with their associated...

Extractive behavior of U(VI) in the paraffin soluble ionic liquid

International Nuclear Information System (INIS)

Rama, R.; Kumaresan, R.; Venkatesan, K.A.; Antony, M.P.; Vasudeva Rao, P.R.

2013-01-01

An Aliquat-336 based ionic liquid namely, tri-n-octylmethylammonium bis(2-ethylhexyl)phosphate ((A3636) + (DEHP) - ) was prepared and studied for the extraction of U(VI) from nitric acid medium. Since the ionic liquid, (A336) + (DEHP) - , was miscible in n-dodecane (n-DD), the extraction of U(VI) in the solution of tri-n-butylphosphate (TBP) in n-DD, was investigated in the presence of small concentrations of ionic liquid. The distribution ratio of U(VI) in 0.3 M (A336) + (DEHP) - /n-DD decreased with increase in the concentration of nitric acid. The effect of concentration of TBP, ionic liquid nitric acid and nitrate ion on the extraction of U(VI) in ionic liquid medium was studied. The mechanistic aspect of extraction was investigated by the slope analysis of the extraction data. The studies indicated the feasibility of modifying the extractive properties of U(VI) in TBP/n-DD using ionic liquid. (author)

Mixed hemimicelles solid-phase extraction based on ionic liquid-coated Fe3O4/SiO2 nanoparticles for the determination of flavonoids in bio-matrix samples coupled with high performance liquid chromatography.

Science.gov (United States)

He, Huan; Yuan, Danhua; Gao, Zhanqi; Xiao, Deli; He, Hua; Dai, Hao; Peng, Jun; Li, Nan

2014-01-10

A novel magnetic solid-phase extraction (MSPE) method based on mixed hemimicelles of room temperature ionic liquids (RTILs) coated Fe3O4/SiO2 nanoparticles (NPs) was developed for simultaneous extraction of trace amounts of flavonoids in bio-matrix samples. A comparative study on the use of RTILs (C16mimBr) and CTAB-coated Fe3O4/SiO2 NPs as sorbents was presented. Owing to bigger adsorption amounts for analytes, RTILs-coated Fe3O4/SiO2 NPs was selected as MSPE materials and three analytes luteolin, quercetin and kaempferol can be quantitatively extracted and simultaneously determined coupled with high performance liquid chromatography (HPLC) in urine samples. No interferences were caused by proteins or endogenous compounds. Good linearity (R(2)>0.9993) for all calibration curves was obtained, and the limits of detection (LOD) for luteolin, quercetin and kaempferol were 0.10 ng/mL, 0.50 ng/mL and 0.20 ng/mL in urine samples, respectively. Satisfactory recoveries (93.5-97.6%, 90.1-95.4% and 93.3-96.6% for luteolin, quercetin and kaempferol) in biological matrices were achieved. It was notable that while using a small amount of Fe3O4/SiO2 NPs (4.0 mg) and C16mimBr (1.0 mg), satisfactory preconcentration factors and extraction recoveries for the three flavonoids were obtained. To the best of our knowledge, this is the first time a mixed hemimicelles MSPE method based on RTILs and Fe3O4/SiO2 NPs magnetic separation has ever been used for pretreatment of complex biological samples. Copyright © 2013 Elsevier B.V. All rights reserved.