Simultaneous enantioselective determination of six pesticides in aqueous environmental samples by chiral liquid chromatography with tandem mass spectrometry.

PubMed

Zhao, Pengfei; Lei, Shuo; Xing, Mingming; Xiong, Shihang; Guo, Xingjie

2018-03-01

A robust and sensitive method was developed for the enantiomeric analysis of six chiral pesticides (including metalaxyl, epoxiconazole, myclobutanil, hexaconazole, napropamide, and isocarbophos) in aquatic environmental samples. The optimized chromatographic conditions for the quantification of all the 12 enantiomers were performed with Chiralcel OD-RH column using mobile phase consisting of 0.1% aqueous formic acid and acetonitrile operated under reversed-phase conditions and then analyzed using liquid chromatography with tandem mass spectrometry. Twelve enantiomers were detected in multiple reaction monitoring mode. Solid-phase extraction and dispersive liquid-liquid microextraction were employed in this study. Response surface methodology was applied to assist in the dispersive liquid-liquid microextraction optimization. Under the optimum conditions, recoveries of pesticides enantiomers varied from 83.0 to 103.2% at two spiked levels with relative standard deviation less than 11.5%. The concentration factors were up to 1000 times. Method detection and quantification limits varied from 0.11 to 0.48 ng/L and from 0.46 to 1.49 ng/L, respectively. Finally, this method was used to determination of the enantiomers composition of the six pesticides in environmental aqueous matrices, which will help better understand the behavior of individual enantiomer and make accurate risk assessment to ecosystems. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Enantioselective analysis of ibuprofen in human plasma by anionic cyclodextrin-modified electrokinetic chromatography.

PubMed

Jabor, Valquíria A P; Lanchote, Vera L; Bonato, Pierina S

2002-09-01

This paper reports the development of a rapid method for the enantioselective analysis of the nonsteroidal anti-inflammatory drug ibuprofen in human plasma by capillary electrophoresis employing the anionic cyclodextrin-modified electrokinetic chromatography mode. Sample cleanup was carried out by acidification with HCl followed by liquid-liquid extraction with hexane:isopropanol (99:1 v/v). The complete enantioselective analysis was performed within 10 min, using 100 mmol L(-1) phosphoric acid/triethanolamine buffer, pH 2.6, containing 2.0% w/v sulfated beta-cyclodextrin as chiral selector; fenoprofen, another nonsteroidal anti-inflammatory drug, was used as internal standard. The calibration curves were linear over the concentration range of 0.25-125.0 microg mL(-1) for each enantiomer of ibuprofen. The mean recoveries for ibuprofen enantiomers were up to 85%. The enantiomers studied could be quantified at three different concentrations (0.5, 5.0 and 50.0 microg mL(-1)) with a coefficient of variation and relative error not higher than 15%. The quantitation limit was 0.2 microg mL(-1) for (+)-(S)- and (-)-(R)-ibuprofen using 1 mL of human plasma. The plasma endogenous compounds and other drugs did not interfere with the present assay. The analysis of real plasma samples obtained from a healthy volunteer after administration of 600 mg of racemic ibuprofen showed a maximum plasma level of 29.6 and 39.9 microg mL(-1) of (-)-(R)- and (+)-(S)-ibuprofen, respectively, and the area under plasma concentration-time curve AUC(0-infinity) (+)-(S)/AUC(0-infinity) (-)-(R) ratio was 1.87.

"Nonsolvent" applications of ionic liquids in biotransformations and organocatalysis.

PubMed

Domínguez de María, Pablo

2008-01-01

The application of room-temperature ionic liquids (RTILs) as (co)solvents and/or reagents is well documented. However, RTILS also have "nonsolvent" applications in biotransformations and organocatalysis. Examples are the anchoring of substrates to RTILs; ionic-liquid-coated enzymes (ILCE) and enzyme-IL colyophilization; the construction of biocatalytic ternary reaction systems; the combination of enzymes, RTILs, membranes, and (bio)electrochemistry; and ionic-liquid-supported organocatalysts. These strategies provide more robust, more efficient, and more enantioselective bio- and organocatalysts with many practical applications. As shown herein, RTILs offer a wide range of promising alternatives to conventional chemistry.

Comparison of liquid and supercritical fluid chromatography mobile phases for enantioselective separations on polysaccharide stationary phases.

PubMed

Khater, Syame; Lozac'h, Marie-Anne; Adam, Isabelle; Francotte, Eric; West, Caroline

2016-10-07

Analysis and production of enantiomerically pure compounds is a major topic of interest when active pharmaceutical ingredients are concerned. Enantioselective chromatography has become a favourite both at the analytical and preparative scales. High-performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC) are dominating the scene and are often seen as complementary techniques. Nowadays, for economic and ecologic reasons, SFC may be preferred over normal-phase HPLC (NPLC) as it allows significant reductions in solvent consumption. However, the transfer of NPLC methods to SFC is not always straightforward. In this study, we compare the retention of achiral molecules and separation of enantiomers under supercritical fluid (carbon dioxide with ethanol or isopropanol) and liquid normal-phase (heptane with ethanol or isopropanol) elution modes with polysaccharide stationary phases in order to explore the differences between the retention and enantioseparation properties between the two modes. Chemometric methods (namely quantitative structure-retention relationships and discriminant analysis) are employed to compare the results obtained on a large set of analytes (171 achiral probes and 97 racemates) and gain some understanding on the retention and separation mechanisms. The results indicate that, contrary to popular belief, carbon dioxide - solvent SFC mobile phases are often weaker eluents than liquid mobile phases. It appears that SFC and NPLC elution modes provide different retention mechanisms. While some enantioseparations are unaffected, facilitating the transfer between the two elution modes, other enantioseparations may be drastically different due to different types and strength of interactions contributing to enantioselectivity. Copyright © 2016 Elsevier B.V. All rights reserved.

Simultaneous probing of bulk liquid phase and catalytic gas-liquid-solid interface under working conditions using attenuated total reflection infrared spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meemken, Fabian; Müller, Philipp; Hungerbühler, Konrad

Design and performance of a reactor set-up for attenuated total reflection infrared (ATR-IR) spectroscopy suitable for simultaneous reaction monitoring of bulk liquid and catalytic solid-liquid-gas interfaces under working conditions are presented. As advancement of in situ spectroscopy an operando methodology for gas-liquid-solid reaction monitoring was developed that simultaneously combines catalytic activity and molecular level detection at the catalytically active site of the same sample. Semi-batch reactor conditions are achieved with the analytical set-up by implementing the ATR-IR flow-through cell in a recycle reactor system and integrating a specifically designed gas feeding system coupled with a bubble trap. By the usemore » of only one spectrometer the design of the new ATR-IR reactor cell allows for simultaneous detection of the bulk liquid and the catalytic interface during the working reaction. Holding two internal reflection elements (IRE) the sample compartments of the horizontally movable cell are consecutively flushed with reaction solution and pneumatically actuated, rapid switching of the cell (<1 s) enables to quasi simultaneously follow the heterogeneously catalysed reaction at the catalytic interface on a catalyst-coated IRE and in the bulk liquid on a blank IRE. For a complex heterogeneous reaction, the asymmetric hydrogenation of 2,2,2-trifluoroacetophenone on chirally modified Pt catalyst the elucidation of catalytic activity/enantioselectivity coupled with simultaneous monitoring of the catalytic solid-liquid-gas interface is shown. Both catalytic activity and enantioselectivity are strongly dependent on the experimental conditions. The opportunity to gain improved understanding by coupling measurements of catalytic performance and spectroscopic detection is presented. In addition, the applicability of modulation excitation spectroscopy and phase-sensitive detection are demonstrated.« less

Simultaneous enantioselective quantification of fluoxetine and norfluoxetine in human milk by direct sample injection using 2-dimensional liquid chromatography-tandem mass spectrometry.

PubMed

Alvim, Joel; Lopes, Bianca Rebelo; Cass, Quezia Bezerra

2016-06-17

A two-dimensional liquid chromatography system coupled to triple quadrupole tandem mass spectrometer (2D LC-MS/MS) was employed for the simultaneously quantification of fluoxetine (FLX) and norfluoxetine (NFLX) enantiomers in human milk by direct injection of samples. A restricted access media of bovine serum albumin octadecyl column (RAM-BSAC18) was used in the first dimension for the milk proteins depletion, while an antibiotic-based chiral column was used in the second dimension. The results herein described show good selectivity, extraction efficiency, accuracy, and precision with limits of quantification in the order of 7.5ngmL(-1)for the FLX enantiomers and 10.0ngmL(-1) for NFLX enantiomers. Furthermore, it represents a practical tool in terms of sustainability for the sample preparation of such a difficult matrix. Copyright © 2016 Elsevier B.V. All rights reserved.

A new and fast DLLME-CE method for the enantioselective analysis of zopiclone and its active metabolite after fungal biotransformation.

PubMed

de Albuquerque, Nayara Cristina Perez; de Gaitani, Cristiane Masetto; de Oliveira, Anderson Rodrigo Moraes

2015-05-10

Zopiclone (ZO) is a chiral drug that undergoes extensive metabolism to N-desmethylzopiclone (N-Des-ZO) and zopiclone-N-oxide (N-Ox-ZO). Pharmacological studies have shown (S)-N-Des-ZO metabolite presents anxiolytic activity and a patent for this metabolite was requested for anxiety treatment and related disorders. In this context, biotransformation employing fungi may be a promising strategy to obtain N-Des-ZO. To perform the biotransformation study in this work, an enantioselective method based on capillary electrophoresis (CE) and dispersive liquid-liquid microextraction (DLLME) was developed. CE analyses were carried out in sodium phosphate buffer (pH 2.5; 50mmolL(-1)) containing 0.5% (w/v) carboxymethyl-β-CD, at a constant voltage of +25kV. DLLME was conducted using 2mL of liquid culture medium pH 9.5. Chloroform (100μL) and methanol (300μL) were employed as extraction and disperser solvent, respectively. After CE and DLLME optimization, the analytical method was fully validated. The method was linear over a concentration range of 90-6000ngmL(-1) for each ZO enantiomer (r>0.999) and 50-1000ngmL(-1) for each N-Des-ZO enantiomer (r>0.998). Absolute recovery of 51 and 82% was achieved for N-Des-ZO and ZO, respectively. The accuracy and precision results agreed with the EMA (European Medicines Agency) guideline, and so did the stability study. Application of the developed method in a biotransformation study was conducted in order to investigate the ability of fungi, belonging to the genus Cunninghamella, in metabolizing ZO chiral drug. Fungi Cunninghamella elegans ATCC 10028B and Cunninghamella echinulata var elegans ATCC 8688A demonstrated to be able to enantioselectively biotransform ZO to its active metabolite, N-Des-ZO. Therefore, the proposed goals of this work, i.e. a fast DLLME-CE method and an outstanding strategy to obtain N-Des-ZO, were successfully attained. Copyright © 2015 Elsevier B.V. All rights reserved.

Development and validation of an UFLC-MS/MS method for enantioselectivity determination of d,l-thero-methylphenidate, d,l-thero-ethylphenidate and d,l-thero-ritalinic acid in rat plasma and its application to pharmacokinetic study.

PubMed

Zhang, Chenghao; Luo, Huafei; Wu, Yubo; Zhang, Junyun; Zhang, Furong; Lin, Guobei; Wang, Hao

2016-02-01

A chiral UFLC-MS/MS method was established and validated for quantifying d-threo-methylphenidate (d-threo-MPH), l-threo-methylphenidate (l-threo-MPH), d-threo-ethylphenidate (d-threo-EPH), l-threo-ethylphenidate (l-threo-EPH) and d,l-threo-ritalinic acid (d,l-threo-RA) in rat plasma over the linearity range of 1-500ng/mL. Chiral separation was performed on an Astec Chirobiotic V2 column (5μm, 250×2.1mm) with isocratic elution using methanol containing 0.003% ammonium acetate (w/v) and 0.003% trifluoroacetic acid (v/v) at a flow of 0.3mL/min. All analytes and IS were extracted from rat plasma by a one-step liquid-liquid extraction (LLE) method. The intra- and inter-run accuracies were within 85-115%, and the intra- and inter-run precision were <10% for all analytes. Extraction recoveries were 55-62% for d-threo-MPH, 54-60% for l-threo-MPH, 55-60% for d-threo-EPH, 53-57% for l-threo-EPH and 25-30% for d,l-threo-RA. The validated UFLC-MS/MS method successfully applied to the pharmacokinetic interaction study of oral d-threo-MPH and l-threo-MPH (alone or in combination) in female Sprague Dawley rats. The EPH was not detected in rat plasma following oral administrated MPH without EtOH. As far as it is known to the authors, this study is the first one step liquid-liquid extraction method to extract and UFLC-MS/MS method to quantify d-threo-MPH, l-threo-MPH, d-threo-EPH, l-threo-EPH and d,l-threo-RA simultaneously. Copyright © 2015 Elsevier B.V. All rights reserved.

Enantioselective ultra high performance liquid and supercritical fluid chromatography: The race to the shortest chromatogram.

PubMed

Ciogli, Alessia; Ismail, Omar H; Mazzoccanti, Giulia; Villani, Claudio; Gasparrini, Francesco

2018-03-01

The ever-increasing need for enantiomerically pure chiral compounds has greatly expanded the number of enantioselective separation methods available for the precise and accurate measurements of the enantiomeric purity. The introduction of chiral stationary phases for liquid chromatography in the last decades has revolutionized the routine methods to determine enantiomeric purity of chiral drugs, agrochemicals, fragrances, and in general of organic and organometallic compounds. In recent years, additional efforts have been placed on faster, enantioselective analytical methods capable to fulfill the high throughput requirements of modern screening procedures. Efforts in this field, capitalizing on improved chromatographic particle technology and dedicated instrumentation, have led to highly efficient separations that are routinely completed on the seconds time scale. An overview of the recent achievements in the field of ultra-high-resolution chromatography on column packed with chiral stationary phases, both based on sub-2 μm fully porous and sub-3 μm superficially porous particles, will be given, with an emphasis on very recent studies on ultrafast chiral separations. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluation of factors influencing the enantioselective enzymatic esterification of lactic acid in ionic liquid.

PubMed

Findrik, Zvjezdana; Németh, Gergely; Gubicza, László; Bélafi-Bakó, Katalin; Vasić-Rački, Durđa

2012-05-01

In this paper esterification of ethanol and lactic acid catalyzed by Candida antarctica B (Novozyme 435) in ionic liquid (Cyphos 104) was studied. The influence of different variables on lipase enantioselectivity and lactic acid conversion was investigated. The variables investigated were ionic liquid mass/lipase mass ratio, water content, alcohol excess and temperature. Using the Design Expert software 2(3) factorial experimental plan (two levels, three factors) was performed to ascertain the effect of selected variables and their interactions on the ethyl lactate enantiomeric excess and lactic acid conversion. The results of the experiments and statistical processing suggest that temperature and alcohol excess have the highest effect on the ethyl lactate enantiomeric excess, while temperature and water content have the highest influence on the lactic acid conversion. The statistical mathematical model developed on the basis of the experimental data showed that the highest enantiomeric excess achieved in the investigated variable range is 34.3%, and the highest conversion is 63.8% at the initial conditions of water content at 8%; 11-fold molar excess of alcohol and temperature at 30 °C.

A combination of directing groups and chiral anion phase-transfer catalysis for enantioselective fluorination of alkenes

PubMed Central

Wu, Jeffrey; Wang, Yi-Ming; Drljevic, Amela; Rauniyar, Vivek; Phipps, Robert J.; Toste, F. Dean

2013-01-01

We report a catalytic enantioselective electrophilic fluorination of alkenes to form tertiary and quaternary C(sp3)-F bonds and generate β-amino- and β-aryl-allylic fluorides. The reaction takes advantage of the ability of chiral phosphate anions to serve as solid–liquid phase transfer catalysts and hydrogen bond with directing groups on the substrate. A variety of heterocyclic, carbocyclic, and acyclic alkenes react with good to excellent yields and high enantioselectivities. Further, we demonstrate a one-pot, tandem dihalogenation–cyclization reaction, using the same catalytic system twice in series, with an analogous electrophilic brominating reagent in the second step. PMID:23922394

Chiral separation and enantioselective degradation of vinclozolin in soils.

PubMed

Liu, Hui; Liu, Donghui; Shen, Zhigang; Sun, Mingjing; Zhou, Zhiqiang; Wang, Peng

2014-03-01

Vinclozolin is a chiral fungicide with potential environmental problems. The chiral separation of the enantiomers and enantioselective degradation in soil were investigated in this work. The enantiomers were separated by high-performance liquid chromatography (HPLC) on Chiralpak IA, IB, and AZ-H chiral columns under normal phase and the influence of the mobile phase composition on the separation was also studied. Complete resolutions were obtained on all three chiral columns under optimized conditions with the same elution order of (+)/(-). The residual analysis of the enantiomers in soil was conducted using accelerate solvent extraction followed by HPLC determination. The recoveries of the enantiomers ranged from 85.7-105.7% with relative standard deviation (SD) of 0.12-3.83%, and the limit of detection (LOD) of the method was 0.013 µg/g. The results showed that the degradations of vinclozolin enantiomers in the soils followed first-order kinetics. Preferential degradation of the (-)-enantiomer was observed only in one soil with the largest |ES| value of 0.047, and no obvious enantioselective degradation was observed in other soils. It was found that the persistence of vinclozolin in soil was related to pH values based on the half-lives. The two enantiomers disappeared about 8 times faster in basic soils than that in neutral or acidic soils. © 2014 Wiley Periodicals, Inc.

Enantioselective toxicities of chiral ionic liquids 1-alkyl-3-methyl imidazolium tartrate on Scenedesmus obliquus.

PubMed

Liu, Huijun; Zhang, Xiaoqiang; Dong, Ying; Chen, Caidong; Zhu, Shimin; Ma, Xiangjuan

2015-12-01

Ionic liquids (ILs) are being used in various industries during the last few decades, while the good solubility and high stability of ILs may pose a potential threat to the aquatic environment. Effect of chiral ionic liquids (CILs) 1-alkyl-3-methyl imidazolium tartrate (RMIM T) on Scenedesmus obliquus (S.obliquus) was studied. The growth rate inhibition and cell membrane permeability increased with increasing RMIM T concentration and increasing alkyl chain lengths. The IC50 values of D-(-)-tartrate 1-hexyl-3-methyl imidazolium (D-(-)-HMIM T) were 28.30, 12.23,10.15 and 14.41 mg/L, respectively, at 24, 48, 72 and 96h. While that of L-(+)-tartrate 1-hexyl-3-methyl imidazolium (L-(+)-HMIM T) were 15.97, 7.91, 9.43 and 12.04 mg/L respectively. The concentration of chl a, chl b and chl (a+b) decreased with increasing RMIM T concentration. The chlorophyll fluorescence parameters (F0, Fv/Fm, Fv/F0, Y(II), ETR and NPQ) were affected by RMIM T, indicating that the RMIM T will damage the PSII, inhibit the transmission of excitation energy, decrease the efficiency of photosynthesis. The results showed that there were enantioselective toxicity of RMIM T to algae, and the toxicity of L-(+)-RMIM T was greater than that of D-(-)-RMIM T, but the enantioselective difference becomes smaller with increasing exposure time, and with the increasing carbon chain length of cation, indicating that cation properties may have a larger effect on toxicity than anion properties. Copyright © 2015 Elsevier B.V. All rights reserved.

Simultaneous enantioselective determination of phenylpyrazole insecticide flufiprole and its chiral metabolite in paddy field ecosystem by ultra-high performance liquid chromatography/tandem mass spectrometry.

PubMed

Li, Jing; Zhang, Yuting; Cheng, Youpu; Yuan, Shankui; Liu, Lei; Shao, Hui; Li, Hui; Li, Na; Zhao, Pengyue; Guo, Yongze

2016-03-20

A novel and sensitive ultra-high performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method was developed and validated for simultaneous enantioselective determination of flufiprole and its hydrolysis metabolite in paddy field ecosystem. The separation and determination were performed using reversed-phase chromatography on a novel cellulose chiral stationary phase, a Lux Cellulose-4 (150 mm × 2.0 mm) column, under isocratic conditions at 0.25 mL/min flow rate. The effects of other four different polysaccharide-based chiral stationary phases (CSPs) on the separation and simultaneous enantioseparation of the two target compounds were also evaluated. The elution orders of the eluting enantiomers were identified by an optical rotation detector. Modified QuEChERS (acronym for Quick, Easy, Cheap, Effective, Rugged and Safe) method and solid-phase extraction (SPE) were used for the enrichment and cleanup of paddy water, rice straw, brown rice and paddy soil samples, respectively. Parameters including the matrix effect, linearity, precision, accuracy and stability were evaluated. Under the optimal conditions, the mean recoveries for all enantiomers from the above four sample matrix were ranged from 83.6% to 107%, with relative standard deviations (RSD) in the range of 1.0-5.8%. Coefficients of determination R(2)≥0.998 were achieved for each enantiomer in paddy water, rice straw, brown rice and paddy soil matrix calibration curves within the range of 5-500 μg/kg. The limits of quantification (LOQ) for all stereoisomers in the above four matrices were all below 2.0 μg/kg. The methodology was successfully applied for simultaneously enantioselective analysis of flufiprole enantiomers and their chiral metabolite in the real samples, indicating its efficacy in investigating the environmental stereochemistry of flufiprole in paddy field ecosystem. Copyright © 2016 Elsevier B.V. All rights reserved.

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

DOEpatents

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.

Chiral ligand exchange high-speed countercurrent chromatography: mechanism, application and comparison with conventional liquid chromatography in enantioseparation of aromatic α-hydroxyl acids

PubMed Central

Tong, Shengqiang; Shen, Mangmang; Cheng, Dongping; Ito, Yoichiro; Yan, Jizhong

2014-01-01

This work concentrates on the separation mechanism and application of chiral ligand exchange high-speed countercurrent chromatography (HSCCC) in enantioseparations, and comparison with traditional chiral ligand exchange high performance liquid chromatography (HPLC). The enantioseparation of ten aromatic α-hydroxyl acids were performed by these two chromatographic methods. Results showed that five of the racemates were successfully enantioseparated by HSCCC while only three of the racemates could be enantioseparated by HPLC using a suitable chiral ligand mobile phase additive. For HSCCC, the two-phase solvent system was composed of butanol-water (1:1, v/v), to which N-n-dodecyl-L-proline was added in the organic phase as chiral ligand and cupric acetate was added in the aqueous phase as a transition metal ion. Various operation parameters in HSCCC were optimized by enantioselective liquid-liquid extraction. Based on the results of the present studies the separation mechanism for HSCCC was proposed. For HPLC, the optimized mobile phase composed of aqueous solution containing 6 mmol L−1 L-phenylalanine and 3 mmol L−1 cupric sulfate and methanol was used for enantioseparation. Among three ligands tested on a conventional reverse stationary phase column, only one was found to be effective. In the present studies HSCCC presented unique advantages due to its high versatility of two-phase solvent systems and it could be used as an alternative method for enantioseparations. PMID:25087742

Enantioselective determination of metconazole in multi matrices by high-performance liquid chromatography.

PubMed

He, Rujian; Fan, Jun; Tan, Qi; Lai, Yecai; Chen, Xiaodong; Wang, Tai; Jiang, Ying; Zhang, Yaomou; Zhang, Weiguang

2018-02-01

A reliable and effective HPLC analytical method has been developed to stereoselectively quantify metconazole in soil and flour matrices. Effects of polysaccharide chiral stationary phase, type and content of alcoholic modifier on separation of racemic metconazole have been discussed in detail. Resolution and quantitative determination of metconazole stereoisomers were performed by using an Enantiopak OD column, with the n-hexane-ethanol mixture (97:3, v/v) at the flow rate of 1.0mL/min. Then, extraction and cleanup procedures followed by the modified QuEChERS (quick, easy, cheap, effective, rugged and safe) method were used for metconazole racemate in soil and flour matrices. The residual analysis method was validated. Good linearity (R 2 ≥ 0.9997) and recoveries (94.98-104.89%, RSD ≤ 2.0%) for four metconazole stereoisomers were obtained. In brief, this proposed method showed good accuracy and precision, which might be applied in enantioselective determination, residual quantitative analysis, and degradation of metconazole in food and environmental matrices. Copyright © 2017 Elsevier B.V. All rights reserved.

Enantioselective extraction of (+)-(S)-citalopram and its main metabolites using a tailor-made stir bar chiral imprinted polymer for their LC-ESI-MS/MS quantitation in urine samples.

PubMed

Unceta, Nora; Gómez-Caballero, Alberto; García, Deiene; Díaz, Goretti; Guerreiro, Antonio; Piletsky, Sergey; Goicolea, M Aránzazu; Barrio, Ramón J

2013-11-15

This paper reports the application of a chiral imprinted polymer (CIP)-coated stir bar for the selective extraction of (+)-(S)-citalopram (SCIT) and its main metabolites, (+)-(S)-desmethylcitalopram (SDCIT) and (+)-(S)-didesmethylcitalopram (SDDCIT), from urine samples. The developed device has been demonstrated to be capable of selectively extracting the three target analytes from urine samples without saturating the imprinted sites. A CIP-coated stir bar sorptive extraction procedure (CIP-SBSE) is proposed for the isolation of SCIT, SDCIT and SDDCIT followed by their subsequent analysis using liquid chromatography ion trap mass spectrometry (LC-ITMS). Deuterated SCIT-d6 was used as an internal standard. The method was validated using a standard procedure, which revealed that a quantification of 5 ng mL(-1) was obtained in urine samples and that the accuracy and precision were within the established values while no matrix effect was observed. Copyright © 2013 Elsevier B.V. All rights reserved.

The application of chiral ultra-high-performance liquid chromatography tandem mass spectrometry to the separation of the zoxamide enantiomers and the study of enantioselective degradation process in agricultural plants.

PubMed

Pan, Xinglu; Dong, Fengshou; Chen, Zenglong; Xu, Jun; Liu, Xingang; Wu, Xiaohu; Zheng, Yongquan

2017-11-24

In this study, an effective and sensitive chiral analytical method was developed to detect zoxamide enantiomers in vegetables, fruits and environmental matrices using ultra-high-performance liquid chromatography-tandem mass spectrometry. Optimal separation conditions were achieved with Lux Amylose-2 chiral column using acetonitrile/water (70:30v/v) as mobile phase with a flow rate and column temperature of 0.5mL/min and 25°C. The absolute configuration, optical rotation and elution order were confirmed for the first time. The average recoveries in all matrices at four spiking levels (0.5, 5, 50, 250μg/kg) ranged from 89.7 to 117.4%, with relative standard deviations being less than 10.9% for two enantiomers. The enantioselective dissipation of zoxamide in tomato showed that (-)-R-zoxamide was preferentially degraded leading to an enrichment of (+)-S-isomer, with half-lives of 3.80 d and 5.17 d, respectively. Inversely, (+)-S-zoxamide degraded faster than (-)-R-zoxamide in pepper (1.95day and 2.28day, respectively) and grape (2.03day and 2.87day). No significant enantioselectivity was observed in cucumber. The results of this study could help facilitate more accurate risk assessments of zoxamide in the future. Copyright © 2017 Elsevier B.V. All rights reserved.

Description and Evaluation of Chiral Interactive Sites on Bonded Cyclodextrin Stationary Phases for Liquid Chromatography

NASA Astrophysics Data System (ADS)

Beesley, Thomas E.

Development of chiral separations has been essential to the drug discovery and development process. The solubility requirements for a number of methods and/or the mobile phase requirements for application of certain detection systems have opened up many opportunities for cyclodextrin-based CSPs for liquid chromatography. Even though a few chiral stationary phases cover a wide area of enantioselectivity, they do not meet the entire needs of the industry. Cyclodextrin phases offer some unique mechanisms and opportunities to resolve chiral separation problems especially in the aqueous reversed-phase and non-aqueous polar organic modes. This chapter addresses the need to understand the chiral stationary phase structure, the mechanisms at work, and the role mobile phase composition plays in driving those mechanisms to produce enantioselectivity. In addition, the development of certain derivatives has played an essential part in expanding that basic role for certain chiral separations. What these derivatives contribute in concert with the basic structure is a critical part of the understanding to the effective use of these phases. During this study it was determined that the role of steric hindrance has been vastly underestimated, both to the extent that it has occurred and to its effectiveness for obtaining enantioselectivity. References to the entire 20-year history of the cyclodextrin phase development and application literature up to this current date have been reviewed and incorporated.

Comparison of three different dispersive liquid-liquid microextraction modes performed on their most usual configurations for the extraction of phenolic, neutral aromatic, and amino compounds from waters.

PubMed

Saraji, Mohammad; Ghambari, Hoda

2018-06-21

In this work we seek clues to select the appropriate dispersive liquid-liquid microextraction mode for extracting three categories of compounds. For this purpose, three common dispersive liquid-liquid microextraction modes were compared under optimized conditions. Traditional dispersive liquid-liquid microextraction, in situ ionic liquid dispersive liquid-liquid microextraction and conventional ionic liquid dispersive liquid-liquid microextraction using chloroform, 1-butyl-3-methylimidazolium tetrafluoroborate, and 1-hexyl-3-methylimidazolium hexafluorophosphate as the extraction solvent, respectively, were considered in this work. Phenolic, neutral aromatic and amino compounds (each category included six members) were studied as analytes. The analytes in the extracts were determined by high-performance liquid chromatography with UV detection. For the analytes with polar functionalities, the in situ ionic liquid dispersive liquid-liquid microextraction mode mostly led to better results. In contrast, for neutral hydrocarbons without polar functionalities, traditional dispersive liquid-liquid microextraction using chloroform produced better results. In this case, where dispersion forces were the dominant interactions in the extraction, the refractive index of solvent and analyte predicted the extraction performance better than the octanol-water partition coefficient. It was also revealed that none of the methods were successful in extracting very hydrophilic analytes (compounds with the log octanol-water partition coefficient < 2). The results of this study could be helpful in selecting a dispersive liquid-liquid microextraction mode for the extraction of various groups of compounds. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Chiral analysis of bambuterol, its intermediate and active drug in human plasma by liquid chromatography-tandem mass spectrometry: Application to a pharmacokinetic study.

PubMed

Zhou, Ting; Liu, Shan; Zhao, Ting; Zeng, Jing; He, Mingzhi; Xu, Beining; Qu, Shanshan; Xu, Ling; Tan, Wen

2015-08-01

A sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed for simultaneous chiral analysis of an antiasthma drug bambuterol, its key intermediate monocarbamate bambuterol and its active drug terbutaline in human plasma. All samples were extracted with ethyl acetate and separated on an Astec Chirobiotic T column under isocratic elution with a mobile phase consisting of methanol and water with the addition of 20mm ammonium acetate and 0.005% (v/v) formic acid at 0.6mL/min. The analytes were detected by a Xevo TQ-S tandem mass spectrometer with positive electrospray ionization in multiple reaction monitoring mode. The established method has high sensitivity with the lower limit of quantifications of 25.00pg/mL for bambuterol enantiomers, and 50.00pg/mL for monocarbamate bambuterol and terbutaline enantiomers, respectively. The calibration curves for bambuterol enantiomers were linear in the range of 25.00-2500pg/mL, and for monocarbamate bambuterol and terbutaline enantiomers were linear in the range of 50.00-5000pg/mL. The intra- and inter-day precisions were <12.4%. All the analytes were separated in 18.0min. For the first time, the validated method was successfully applied to an enantioselective pharmacokinetic study of rac-bambuterol in 8 healthy volunteers. According to the results, this chiral LC-MS/MS assay provides a suitable and robust method for the enantioselectivity and interaction study of the prodrug bambuterol, the key intermediate monocarbamate bambuterol and its active drug terbutaline in human. Copyright © 2015 Elsevier B.V. All rights reserved.

Enantioselective determination of 3-n-butylphthalide (NBP) in human plasma by liquid chromatography on a teicoplanin-based chiral column coupled with tandem mass spectrometry.

PubMed

Diao, Xingxing; Ma, Zhiyu; Lei, Peng; Zhong, Dafang; Zhang, Yifan; Chen, Xiaoyan

2013-11-15

A novel and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to determine the exposure of 3-n-butylphthalide (NBP) enantiomers in human plasma. The NBP enantiomers were extracted from human plasma using methyl tert-butyl ether. The baseline separation of R-(+)-NBP and S-(-)-NBP was achieved within 11.0min using a teicoplanin-based Astec Chirobiotic T column (250mm×4.6mm i.d., 5μm) under isocratic conditions at a flow rate of 0.6mL/min. The selection of the chiral stationary phase and the effect of the mobile phase composition on the resolution of the enantiomers were discussed. The selectivity, linearity, precision, accuracy, matrix effect, recovery, and stability were evaluated under optimized conditions. The LC-MS/MS method using 200μL of human plasma was linear over the concentration range of 5.00-400ng/mL for each enantiomer. The lower limit of quantification (LLOQ) for both enantiomers was 5.00ng/mL. The intra- and inter-assay precision values of the replicated quality control samples were within 8.0% for each enantiomer. The mean accuracy values for the quality control samples were within ±6.1% of the nominal values for R-(+)-NBP and S-(-)-NBP. No chiral inversion was observed during sample storage, preparation, and analysis. The method proved suitable for enantioselective pharmacokinetic studies of NBP after an oral administration of a therapeutic dose of racemic NBP. Copyright © 2013 Elsevier B.V. All rights reserved.

Enantioselective determination of representative profens in wastewater by a single-step sample treatment and chiral liquid chromatography-tandem mass spectrometry.

PubMed

Caballo, C; Sicilia, M D; Rubio, S

2015-03-01

This manuscript describes, for the first time, the simultaneous enantioselective determination of ibuprofen, naproxen and ketoprofen in wastewater based on liquid chromatography tandem mass spectrometry (LC-MS/MS). The method uses a single-step sample treatment based on microextraction with a supramolecular solvent made up of hexagonal inverted aggregates of decanoic acid, formed in situ in the wastewater sample through a spontaneous self-assembly process. Microextraction of profens was optimized and the analytical method validated. Isotopically labeled internal standards were used to compensate for both matrix interferences and recoveries. Apparent recoveries for the six enantiomers in influent and effluent wastewater samples were in the interval 97-103%. Low method detection limits (MDLs) were obtained (0.5-1.2 ng L(-1)) as a result of the high concentration factors achieved in the microextraction process (i.e. actual concentration factors 469-736). No analyte derivatization or evaporation of extracts, as it is required with GC-MS, was necessary. Relative standard deviations for enantiomers in wastewater were always below 8%. The method was applied to the determination of the concentrations and enantiomeric fractions of the targeted analytes in influents and effluents from three wastewater treatment plants. All the values found for profen enantiomers were consistent with those previously reported and confirmed again the suitability of using the enantiomeric fraction of ibuprofen as an indicator of the discharge of untreated or poorly treated wastewaters. Both the analytical and operational features of this method make it applicable to the assessment of the enantiomeric fate of profens in the environment. Copyright © 2014 Elsevier B.V. All rights reserved.

Enantiomerization and enantioselective bioaccumulation of metalaxyl in Tenebrio molitor larvae.

PubMed

Gao, Yongxin; Wang, Huili; Qin, Fang; Xu, Peng; Lv, Xiaotian; Li, Jianzhong; Guo, Baoyuan

2014-02-01

The enantiomerization and enantioselective bioaccumulation of metalaxyl by a single dose of exposure to Tenebrio molitor larvae under laboratory condition were studied by high-performance liquid chromatography tandem mass spectroscopy (HPLC-MS/MS) based on a ChiralcelOD-3R [cellulosetris-tris-(3, 5-dichlorophenyl-carbamate)] column. Exposure of enantiopure R-metalaxyl and S-metalaxyl in Tenebrio molitor larvae exhibited significant enantiomerization, with formation of the R enantiomers from the S enantiomers, and vice versa, which might be attributed to the chiral pesticide catalyzed by a certain enzyme in Tenebrio molitor larvae. Enantiomerization was not observed in wheat bran during the period of 21 d. In addition, bioaccumulation of rac-metalaxyl in Tenebrio molitor larvae was enantioselective with a preferential accumulation of S-metalaxyl. These results showed that enantioselectivity was caused not only by actual degradation and metabolism but also by enantiomerization, which was an important process in the environmental fate and behavior of metalaxyl enantiomers. Copyright © 2013 Wiley Periodicals, Inc.

Quantitative ionspray liquid chromatographic/tandem mass spectrometric determination of reserpine in equine plasma.

PubMed

Anderson, M A; Wachs, T; Henion, J D

1997-02-01

A method based on ionspray liquid chromatography/tandem mass spectrometry (LC/MS/MS) was developed for the determination of reserpine in equine plasma. A comparison was made of the isolation of reserpine from plasma by liquid-liquid extraction and by solid-phase extraction. A structural analog, rescinnamine, was used as the internal standard. The reconstituted extracts were analyzed by ionspray LC/MS/MS in the selected reaction monitoring (SRM) mode. The calibration graph for reserpine extracted from equine plasma obtained using liquid-liquid extraction was linear from 10 to 5000 pg ml-1 and that using solid-phase extraction from 100 to 5000 pg ml-1. The lower level of quantitation (LLQ) using liquid-liquid and solid-phase extraction was 50 and 200 pg ml-1, respectively. The lower level of detection for reserpine by LC/MS/MS was 10 pg ml-1. The intra-assay accuracy did not exceed 13% for liquid-liquid and 12% for solid-phase extraction. The recoveries for the LLQ were 68% for liquid-liquid and 58% for solid-phase extraction.

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

PubMed

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.

Method and apparatus for continuous flow injection extraction analysis

DOEpatents

Hartenstein, Steven D.; Siemer, Darryl D.

1992-01-01

A method and apparatus for a continuous flow injection batch extraction aysis system is disclosed employing extraction of a component of a first liquid into a second liquid which is a solvent for a component of the first liquid, and is immiscible with the first liquid, and for separating the first liquid from the second liquid subsequent to extraction of the component of the first liquid.

Determination of sulfonamides in butter samples by ionic liquid magnetic bar liquid-phase microextraction high-performance liquid chromatography.

PubMed

Wu, Lijie; Song, Ying; Hu, Mingzhu; Xu, Xu; Zhang, Hanqi; Yu, Aimin; Ma, Qiang; Wang, Ziming

2015-01-01

A novel, simple, and environmentally friendly pretreatment method, ionic liquid magnetic bar liquid-phase microextraction, was developed for the determination of sulfonamides in butter samples by high-performance liquid chromatography. The ionic liquid magnetic bar was prepared by inserting a stainless steel wire into the hollow of a hollow fiber and immobilizing ionic liquid in the micropores of the hollow fiber. In the extraction process, the ionic liquid magnetic bars were used to stir the mixture of sample and extraction solvent and enrich the sulfonamides in the mixture. After extraction, the analyte-adsorbed ionic liquid magnetic bars were readily isolated with a magnet from the extraction system. It is notable that the present method was environmentally friendly since water and only several microliters of ionic liquid were used in the whole extraction process. Several parameters affecting the extraction efficiency were investigated and optimized, including the type of ionic liquid, sample-to-extraction solvent ratio, the number of ionic liquid magnetic bars, extraction temperature, extraction time, salt concentration, stirring speed, pH of the extraction solvent, and desorption conditions. The recoveries were in the range of 73.25-103.85 % and the relative standard deviations were lower than 6.84 %. The experiment results indicated that the present method was effective for the extraction of sulfonamides in high-fat content samples.

APPLICATIONS OF CAPILLARY ELECTROPHORESIS TO THE STUDY OF CHIRAL ENVIRONMENTAL POLLUTANTS: ENANTIOMER SEPARATION AND MEASUREMENTS OF ENANTIOSELECTIVITY

EPA Science Inventory

CE is rarely used for routine environmental analysis of organic pollutants -- certainly not to the extent of gas chromatography or high pressure liquid chromatography. There are advantages to CE, however, that belie this lack of application. For example, CE is preferred over GC f...

Research News: Emulsion Liquid Membrane Extraction in a Hollow-Fiber Contactor

NASA Technical Reports Server (NTRS)

Wiencek, John M.; Hu, Shih-Yao

2000-01-01

This article describes how ELMs (emulsion liquid membranes) can be used for extraction. The article addresses the disadvantages of ELM extraction in a stirred contactor, and the advantages of SELMs (supported emulsion liquid membranes). The introduction of the article provides background information on liquid-liquid solvent extraction and dispersion-free solvent extraction.

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

ERIC Educational Resources Information Center

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.…

Atomizing, continuous, water monitoring module

DOEpatents

Thompson, C.V.; Wise, M.B.

1997-07-08

A system for continuously analyzing volatile constituents of a liquid is described. The system contains a pump for continuously pumping the liquid to be tested at a predetermined flow rate into an extracting container through a liquid directing tube having an orifice at one end and positioned to direct the liquid into the extracting container at a flow rate sufficient to atomize the liquid within the extracting container. A continuous supply of helium carrier gas at a predetermined flow rate is directed through a tube into the extracting container and co-mingled with the atomized liquid to extract the volatile constituents contained within the atomized liquid. The helium containing the extracted volatile constituents flows out of the extracting container into a mass spectrometer for an analysis of the volatile constituents of the liquid. 3 figs.

Atomizing, continuous, water monitoring module

DOEpatents

Thompson, Cyril V.; Wise, Marcus B.

1997-01-01

A system for continuously analyzing volatile constituents of a liquid is described. The system contains a pump for continuously pumping the liquid to be tested at a predetermined flow rate into an extracting container through a liquid directing tube having an orifice at one end and positioned to direct the liquid into the extracting container at a flow rate sufficient to atomize the liquid within the extracting container. A continuous supply of helium carrier gas at a predetermined flow rate is directed through a tube into the extracting container and co-mingled with the atomized liquid to extract the volatile constituents contained within the atomized liquid. The helium containing the extracted volatile constituents flows out of the extracting container into a mass spectrometer for an analysis of the volatile constituents of the liquid.

Enantioselective determination of metoprolol and its metabolites in human urine high-performance liquid chromatography with fluorescence detection (HPLC-FLD) and tandem mass spectrometry (MS/MS).

PubMed

Baranowska, Irena; Adolf, Weronika; Magiera, Sylwia

2015-11-01

A sensitive, stereoselective assay using solid phase extraction and high-performance liquid chromatography (HPLC) with fluorescence detection (FLD) was developed and validated for the analysis of enantiomers of metoprolol and its metabolites (α-hydroxymetoprolol, O-desmethylmetoprolol). Chiral separation was achieved using a CHIRALCEL OD-RH column, packed with cellulose tris-(3,5-dimethylphenyl-carbamate) stationary phase, employing a mobile phase composed by a mixture of 0.2% diethylamine in water and acetonitrile in gradient elution mode. Linear calibration curves were obtained over the range of 0.025-2.0μg/mL (R(2)>0.994) in urine for both enantiomers of metoprolol and its metabolites with quantitation limit of 0.025μg/mL. Intra and inter-day precision and accuracy were below 15% for both metoprolol and metabolites enantiomers. The recovery of enantiomer of metoprolol and its metabolite was greater than 68.0%, utilizing a SPE procedure. The method was tested with urine quality control samples and human urine fractions after administration of 50mg rac-metoprolol. Copyright © 2015 Elsevier B.V. All rights reserved.

Analysis of carvedilol enantiomers in human plasma using chiral stationary phase column and liquid chromatography with tandem mass spectrometry.

PubMed

Poggi, Josiane Cristófani; Da Silva, Flávia Garcez; Coelho, Eduardo Barbosa; Marques, Maria Paula; Bertucci, Carlo; Lanchote, Vera Lucia

2012-03-01

Carvedilol is an antihypertensive drug available as a racemic mixture. (-)-(S)-carvedilol is responsible for the nonselective β-blocker activity but both enantiomers present similar activity on α(1)-adrenergic receptor. To our knowledge, this is the first study of carvedilol enantiomers in human plasma using a chiral stationary phase column and liquid chromatography with tandem mass spectrometry. The method involves plasma extraction with diisopropyl ether using metoprolol as internal standard and direct separation of the carvedilol enantiomers on a Chirobiotic T® (Teicoplanin) column. Protonated ions [M + H](+) and their respective ion products were monitored at transitions of 407 > 100 for the carvedilol enantiomers and 268 > 116 for the internal standard. The quantification limit was 0.2 ng ml(-1) for both enantiomers in plasma. The method was applied to study enantioselectivity in the pharmacokinetics of carvedilol administered as a single dose of 25 mg to a hypertensive patient. The results showed a higher plasma concentration of (+)-(R)-carvedilol (AUC(0-∞) 205.52 vs. 82.61 (ng h) ml(-1)), with an enantiomer ratio of 2.48. Copyright © 2012 Wiley Periodicals, Inc.

Ionic Liquids as Extraction Media for Metal Ions

NASA Astrophysics Data System (ADS)

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.

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.

PubMed

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 of neodymium(III) by dialkylphosphate ionic liquids from acidic medium: the importance of the ionic liquid cation.

PubMed

Rout, Alok; Kotlarska, Justyna; Dehaen, Wim; Binnemans, Koen

2013-10-21

The ionic liquids 1-hexyl-3-methylimidazolium bis(2-ethylhexyl)phosphate, [C6mim][DEHP], 1-hexyl-1-methylpyrrolidinium bis(2-ethylhexyl)phosphate, [C6mpyr][DEHP], and tetrabutylammonium bis(2-ethylhexyl)phosphate, [N4444][DEHP], were prepared and characterized using (1)H and (13)C NMR spectroscopy. The extraction behavior of neodymium(iii) from nitrate medium by these ionic liquids, diluted with the room temperature ionic liquids 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [C6mim][NTf2], 1-hexyl-3-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, [C6mpyr][NTf2], and tributylmethylammonium bis(trifluoromethylsulfonyl)imide, [N1444][NTf2], was studied. The distribution ratio of neodymium(iii) was measured as a function of various parameters, such as pH, concentration of the ionic liquid extractant, nature of diluents, concentration of ionic liquid cations and nitrate anions in the aqueous phase. The extraction behavior was compared with that obtained for a solution of the molecular extractant bis(2-ethylhexyl)phosphoric acid (DEHPA) in an ionic liquid diluent. The extraction of neodymium(iii) in the ionic liquids [C6mim][DEHP] and [C6mpyr][DEHP] showed markedly different extraction properties in comparison with that of the quaternary ammonium analogue [N4444][DEHP], especially concerning the pH dependence of the extraction process. These results show that the extraction process can be tuned by the selection of the ionic liquid cation. The extraction experiments also included the trivalent rare-earth ions lanthanum(iii), cerium(iii), praseodymium(iii), ytterbium(iii) and yttrium(iii). Studies of the stripping behavior and the reusability of the ionic liquids were carried out, which indicate that the ionic liquids can be reused with no loss in activity.

Comparative Evaluation of Different Cell Lysis and Extraction Methods for Studying Benzo(a)pyrene Metabolism in HT-29 Colon Cancer Cell Cultures

PubMed Central

Myers, Jeremy N.; Rekhadevi, Perumalla V.; Ramesh, Aramandla

2011-01-01

Lysis and extraction of cells are essential sample processing steps for investigations pertaining to metabolism of xenobiotics in cell culture studies. Of particular importance to these procedures are maintaining high lysis efficiency and analyte integrity as they influence the qualitative and quantitative distribution of drug and toxicant metabolites in the intra- and extracellular milieus. In this study we have compared the efficiency of different procedures viz. homogenization, sonication, bead beating, and molecular grinding resin treatment for disruption of HT-29 colon cells exposed to benzo(a)pyrene (BaP), a polycyclic aromatic hydrocarbon (PAH) compound and a suspected colon carcinogen. Also, we have evaluated the efficiency of various procedures for extracting BaP parent compound/metabolites from colon cells and culture media prior to High Performance Liquid Chromatography (HPLC) analyses. The extraction procedures include solid phase extraction, solid-supported liquid- liquid extraction, liquid-liquid extraction, and homogeneous liquid- liquid extraction. Our findings showed that bead-beating in combination with detergent treatment of cell pellet coupled with liquid-liquid extraction yielded greater concentrations of BaP metabolites compared to the other methods employed. Our method optimization strategy revealed that disruption of HT-29 colon cells by a combination of mechanical and chemical lysis followed by liquid-liquid extraction is efficient and robust enough for analyzing BaP metabolites from cell culture studies. PMID:21865728

Metal separation from mixed types of batteries using selective precipitation and liquid-liquid extraction techniques.

PubMed

Provazi, Kellie; Campos, Beatriz Amaral; Espinosa, Denise Crocce Romano; Tenório, Jorge Alberto Soares

2011-01-01

The purpose of this paper is to study metal separation from a sample composed of a mixture of the main types of spent household batteries, using a hydrometallurgical route, comparing selective precipitation and liquid-liquid extraction separation techniques. The preparation of the solution consisted of: grinding the waste of mixed batteries, reduction and volatile metals elimination using electric furnace and acid leaching. From this solution two different routes were studied: selective precipitation with sodium hydroxide and liquid-liquid extraction using Cyanex 272 [bis(2,4,4-trimethylpentyl) phosphoric acid] as extracting agent. The best results were obtained from liquid-liquid extraction in which Zn had a 99% extraction rate at pH 2.5. More than 95% Fe was extracted at pH 7.0, the same pH at which more than 90% Ce was extracted. About 88% Mn, Cr and Co was extracted at this pH. At pH 3.0, more than 85% Ni was extracted, and at pH 3.5 more than 80% of Cd and La was extracted. Copyright © 2010 Elsevier Ltd. All rights reserved.

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

PubMed

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

2016-10-01

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

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

PubMed

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.

Enantioselective degradation of Myclobutanil and Famoxadone in grape.

PubMed

Lin, Chunmian; Zhang, Lijun; Zhang, Hu; Wang, Qiang; Zhu, Jiahong; Wang, Jianmei; Qian, Mingrong

2018-01-01

The enantioselective degradation of myclobutanil and famoxadone enantiomers in grape under open field was investigated in this study. The absolute configuration of myclobutanil and famoxadone enantiomers was determined by the combination of experimental electronic circular dichroism (ECD) and calculated ECD spectra. The enantiomers residues of myclobutanil and famoxadone in grape were measured by sensitive high-performance liquid chromatography/tandem mass spectrometry (HPLC-MS/MS). The linearity, precision, accuracy, matrix effect, and stability were assessed. And the limit of quantification (LOQ) for each enantiomer of myclobutanil and famoxadone in grape was evaluated to be 1.5 and 2 μg kg -1 . The myclobutanil and famoxadone showed the enantioselective degradation in grape, and the enantioselectivity of degradation for myclobutanil was more pronounced than that for famoxadone. The half-lives were 13.1 days and 25.7 days for S-(+)-myclobutanil and R-(-)-myclobutanil in grape, separately. The half-life of S-(+)-famoxadone was 31.5 days slightly shorter than that of R-(-)-famoxadone with half-life being 38.5 days in grape. The probable reasons for the enantioselective degradation behavior of these two fungicides were also discussed. The results in the article might provide a reference to better assess the risks of myclobutanil and famoxadone enantiomers in grapes to human and environment. Graphical abstract The enantioselective analysis of myclobutanil and famoxadone in grape.

Understanding gas capacity, guest selectivity, and diffusion in porous liquids† †Electronic supplementary information (ESI) available: Detailed synthetic procedures, experimental details and measurements (PDF). See DOI: 10.1039/c6sc05196k Click here for additional data file.

PubMed Central

Greenaway, Rebecca L.; Holden, Daniel; Eden, Edward G. B.; Stephenson, Andrew; Yong, Chin W.; Bennison, Michael J.; Hasell, Tom; Briggs, Michael E.; James, Stuart L.

2017-01-01

Porous liquids are a new class of material that could have applications in areas such as gas separation and homogeneous catalysis. Here we use a combination of measurement techniques, molecular simulations, and control experiments to advance the quantitative understanding of these liquids. In particular, we show that the cage cavities remain unoccupied in the absence of a suitable guest, and that the liquids can adsorb large quantities of gas, with gas occupancy in the cages as high as 72% and 74% for Xe and SF6, respectively. Gases can be reversibly loaded and released by using non-chemical triggers such as sonication, suggesting potential for gas separation schemes. Diffusion NMR experiments show that gases are in dynamic equilibrium between a bound and unbound state in the cage cavities, in agreement with recent simulations for related porous liquids. Comparison with gas adsorption in porous organic cage solids suggests that porous liquids have similar gas binding affinities, and that the physical properties of the cage molecule are translated into the liquid state. By contrast, some physical properties are different: for example, solid homochiral porous cages show enantioselectivity for chiral aromatic alcohols, whereas the equivalent homochiral porous liquids do not. This can be attributed to a loss of supramolecular organisation in the isotropic porous liquid. PMID:28553499

Ternary liquid-liquid equilibria for the phenolic compounds extraction from artificial textile industrial waste

NASA Astrophysics Data System (ADS)

Fardhyanti, Dewi Selvia; Prasetiawan, Haniif; Hermawan, Sari, Lelita Sakina

2017-03-01

Liquid waste in textile industry contains large amounts of dyes and chemicals which are capable of harming the environment and human health. It is due to liquid waste characteristics which have high BOD, COD, temperature, dissolved and suspended solid. One of chemical compound which might be harmful for environment when disposed in high concentration is phenol. Currently, Phenol compound in textile industrial waste has reached 10 ppm meanwhile maximum allowable phenol concentration is not more than 0.2 ppm. Otherwise, Phenol also has economic value as feedstock of plastic, pharmaceutical and cosmetic industry. Furthermore, suitable method to separate phenol from waste water is needed. In this research, liquid - liquid extraction method was used with extraction time for 70 minutes. Waste water sample was then separated into two layers which are extract and raffinate. Thereafter, extract and raffinate were then tested by using UV-Vis Spectrophotometer to obtained liquid - liquid equilibrium data. Aim of this research is to study the effect of temperature, stirring speed and type of solvent to obtain distribution coefficient (Kd), phenol yield and correlation of Three-Suffix Margules model for the liquid - liquid extraction data equilibrium. The highest extraction yield at 80.43 % was found by using 70% methanol as solvent at extraction temperature 50 °C with stirring speed 300 rpm, coefficient distribution was found 216.334. From this research it can be concluded that Three-Suffix Margules Model is suitable to predict liquid - liquid equilibrium data for phenol system.

Sorption and selective chromatographic properties of isomer-selective composite sorbent based on a eutectic mixture of nematic liquid crystals and perbenzoylated β-cyclodextrin

NASA Astrophysics Data System (ADS)

Onuchak, L. A.; Kapralova, T. S.; Kuraeva, Yu. G.; Belousova, Z. P.; Stepanova, R. F.

2015-12-01

Mesomorphic, sorption, and selective properties of a three-component sorbent based on a mixture of nematic ( N) liquid crystals of 4-methoxy-4'-ethoxyazoxybenzene (MEAB) and 4,4'-diethoxyazoxybenzene (azoxyphenetol, AOP) of an eutectic composition and heptakis-(2,3,6-tri- O-benzoyl)-β-cyclodextrin (Bz-β-CD) are studied. For 30 organic compounds of different classes with linear and cyclic molecular structures, including optical isomers of limonene, pinene, camphene, and butanediol-2,3, thermodynamic functions are determined for their gas-phase sorption using a three-component MEAB-AOP-Bz-β- CD sorbent (62: 28: 10 wt %). It is found that the investigated sorbent possesses high structural selectivity (αp/m = 1.128-1.059, 100-130°C, N) and moderate enantioselectivity (1.07-1.02) within a broad temperature range (95-170°C) including both mesomorphic and isotropic phases of the sorbent. It is shown that the enantioselectivity of the sorbent is apparent under conditions of both increasing retention when a chiral Bz-β-CD additive is introduced into the MEAB-AOP system (limonenes, pinenes, camphenes) and decreasing retention (butanediols-2,3).

Liquid-liquid extraction of actinides, lanthanides, and fission products by use of ionic liquids: from discovery to understanding.

PubMed

Billard, Isabelle; Ouadi, Ali; Gaillard, Clotilde

2011-06-01

Liquid-liquid extraction of actinides and lanthanides by use of ionic liquids is reviewed, considering, first, phenomenological aspects, then looking more deeply at the various mechanisms. Future trends in this developing field are presented.

A microfluidic study of liquid-liquid extraction mediated by carbon dioxide.

PubMed

Lestari, Gabriella; Salari, Alinaghi; Abolhasani, Milad; Kumacheva, Eugenia

2016-07-05

Liquid-liquid extraction is an important separation and purification method; however, it faces a challenge in reducing the energy consumption and the environmental impact of solvent (extractant) recovery. The reversible chemical reactions of switchable solvents (nitrogenous bases) with carbon dioxide (CO2) can be implemented in reactive liquid-liquid extraction to significantly reduce the cost and energy requirements of solvent recovery. The development of new effective switchable solvents reacting with CO2 and the optimization of extraction conditions rely on the ability to evaluate and screen the performance of switchable solvents in extraction processes. We report a microfluidic strategy for time- and labour-efficient studies of CO2-mediated solvent extraction. The platform utilizes a liquid segment containing an aqueous extractant droplet and a droplet of a solution of a switchable solvent in a non-polar liquid, with gaseous CO2 supplied to the segment from both sides. Following the reaction of the switchable solvent with CO2, the solvent becomes hydrophilic and transfers from the non-polar solvent to the aqueous droplet. By monitoring the time-dependent variation in droplet volumes, we determined the efficiency and extraction time for the CO2-mediated extraction of different nitrogenous bases in a broad experimental parameter space. The platform enables a significant reduction in the amount of switchable solvents used in these studies, provides accurate temporal characterization of the liquid-liquid extraction process, and offers the capability of high-throughput screening of switchable solvents.

Liquid-Liquid Extraction of Insecticides from Juice: An Analytical Chemistry Laboratory Experiment

ERIC Educational Resources Information Center

Radford, Samantha A.; Hunter, Ronald E., Jr.; Barr, Dana Boyd; Ryan, P. Barry

2013-01-01

A laboratory experiment was developed to target analytical chemistry students and to teach them about insecticides in food, sample extraction, and cleanup. Micro concentrations (sub-microgram/mL levels) of 12 insecticides spiked into apple juice samples are extracted using liquid-liquid extraction and cleaned up using either a primary-secondary…

The limit of the film extraction technique for annular two-phase flow in a small tube

DOE Office of Scientific and Technical Information (OSTI.GOV)

Helm, D.E.; Lopez de Bertodano, M.; Beus, S.G.

1999-07-01

The limit of the liquid film extraction technique was identified in air-water and Freon-113 annular two-phase flow loops. The purpose of this research is to find the limit of the entrainment rate correlation obtained by Lopez de Bertodano et. al. (1998). The film extraction technique involves the suction of the liquid film through a porous tube and has been widely used to obtain annular flow entrainment and entrainment rate data. In these experiments there are two extraction probes. After the first extraction the entrained droplets in the gas core deposit on the tube wall. A new liquid film develops entirelymore » from liquid deposition and a second liquid film extraction is performed. While it is assumed that the entire liquid film is removed after the first extraction unit, this is not true for high liquid flow. At high liquid film flows the interfacial structure of the film becomes frothy. Then the entire liquid film cannot be removed at the first extraction unit, but continues on and is extracted at the second extraction unit. A simple model to characterize the limit of the extraction technique was obtained based on the hypothesis that the transition occurs due to a change in the wave structure. The resulting dimensionless correlation agrees with the data.« less

The limit of the film extraction technique for annular two-phase flow in a small tube

DOE Office of Scientific and Technical Information (OSTI.GOV)

Helm, D.E.; Lopez de Bertodano, M.; Beus, S.G.

1999-07-01

The limit of the liquid film extraction technique was identified in air-water and Freon-113 annular two-phase flow loops. The purpose of this research is to find the limit of the entrainment rate correlation obtained by Lopez de Bertodano et al. (1998). The film extraction technique involves the suction of the liquid film through a porous tube and has been widely used to obtain annular flow entrainment and entrainment rate data. In the experiments there are two extraction probes. After the first extraction the entrained droplets in the gas core deposit on the tube wall. A new liquid film develops entirelymore » from liquid deposition and a second liquid film extraction is performed. While it is assumed that the entire liquid film is removed after the first extraction unit, this is not true for high liquid flow. At high liquid film flows the interfacial structure of the film becomes frothy. Then the entire liquid film cannot be removed at the first extraction unit, but continues on and is extracted at the second extraction unit. A simple model to characterize the limit of the extraction technique was obtained based on the hypothesis that the transition occurs due to a change in the wave structure. The resulting dimensionless correlation agrees with the data.« less

Determination of diflubenzuron and chlorbenzuron in fruits by combining acetonitrile-based extraction with dispersive liquid-liquid microextraction followed by high-performance liquid chromatography.

PubMed

Ruan, Chunqiang; Zhao, Xiang; Liu, Chenglan

2015-09-01

In this study, a simple and low-organic-solvent-consuming method combining an acetonitrile-partitioning extraction procedure followed by "quick, easy, cheap, effective, rugged and safe" cleanup with ionic-liquid-based dispersive liquid-liquid microextraction and high-performance liquid chromatography with diode array detection was developed for the determination of diflubenzuron and chlorbenzuron in grapes and pears. Ionic-liquid-based dispersive liquid-liquid microextraction was performed using the ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate as the extractive solvent and acetonitrile extract as the dispersive solvent. The main factors influencing the efficiency of the dispersive liquid-liquid microextraction were evaluated, including the extractive solvent type and volume and the dispersive solvent volume. The validation parameters indicated the suitability of the method for routine analyses of benzoylurea insecticides in a large number of samples. The relative recoveries at three spiked levels ranged between 98.6 and 109.3% with relative standard deviations of less than 5.2%. The limit of detection was 0.005 mg/kg for the two insecticides. The proposed method was successfully used for the rapid determination of diflubenzuron and chlorbenzuron residues in real fruit samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Extraction of S- and N-compounds from the mixture of hydrocarbons by ionic liquids as selective solvents.

PubMed

Gabrić, Beata; Sander, Aleksandra; Cvjetko Bubalo, Marina; Macut, Dejan

2013-01-01

Liquid-liquid extraction is an alternative method that can be used for desulfurization and denitrification of gasoline and diesel fuels. Recent approaches employ different ionic liquids as selective solvents, due to their general immiscibility with gasoline and diesel, negligible vapor pressure, and high selectivity to sulfur- and nitrogen-containing compounds. For that reason, five imidazolium-based ionic liquids and one pyridinium-based ionic liquid were selected for extraction of thiophene, dibenzothiophene, and pyridine from two model solutions. The influences of hydrodynamic conditions, mass ratio, and number of stages were investigated. Increasing the mass ratio of ionic liquid/model fuel and multistage extraction promotes the desulfurization and denitrification abilities of the examined ionic liquids. All selected ionic liquids can be reused and regenerated by means of vacuum evaporation.

Extraction of S- and N-Compounds from the Mixture of Hydrocarbons by Ionic Liquids as Selective Solvents

PubMed Central

Gabrić, Beata; Sander, Aleksandra; Cvjetko Bubalo, Marina; Macut, Dejan

2013-01-01

Liquid-liquid extraction is an alternative method that can be used for desulfurization and denitrification of gasoline and diesel fuels. Recent approaches employ different ionic liquids as selective solvents, due to their general immiscibility with gasoline and diesel, negligible vapor pressure, and high selectivity to sulfur- and nitrogen-containing compounds. For that reason, five imidazolium-based ionic liquids and one pyridinium-based ionic liquid were selected for extraction of thiophene, dibenzothiophene, and pyridine from two model solutions. The influences of hydrodynamic conditions, mass ratio, and number of stages were investigated. Increasing the mass ratio of ionic liquid/model fuel and multistage extraction promotes the desulfurization and denitrification abilities of the examined ionic liquids. All selected ionic liquids can be reused and regenerated by means of vacuum evaporation. PMID:23843736

Displacement-dispersive liquid-liquid microextraction based on solidification of floating organic drop of trace amounts of palladium in water and road dust samples prior to graphite furnace atomic absorption spectrometry determination.

PubMed

Ghanbarian, Maryam; Afzali, Daryoush; Mostafavi, Ali; Fathirad, Fariba

2013-01-01

A new displacement-dispersive liquid-liquid microextraction method based on the solidification of floating organic drop was developed for separation and preconcentration of Pd(ll) in road dust and aqueous samples. This method involves two steps of dispersive liquid-liquid microextraction based on solidification. In Step 1, Cu ions react with diethyldithiocarbamate (DDTC) to form Cu-DDTC complex, which is extracted by dispersive liquid-liquid microextraction based on a solidification procedure using 1-undecanol (extraction solvent) and ethanol (dispersive solvent). In Step 2, the extracted complex is first dispersed using ethanol in a sample solution containing Pd ions, then a dispersive liquid-liquid microextraction based on a solidification procedure is performed creating an organic drop. In this step, Pd(ll) replaces Cu(ll) from the pre-extracted Cu-DDTC complex and goes into the extraction solvent phase. Finally, the Pd(ll)-containing drop is introduced into a graphite furnace using a microsyringe, and Pd(ll) is determined using atomic absorption spectrometry. Several factors that influence the extraction efficiency of Pd and its subsequent determination, such as extraction and dispersive solvent type and volume, pH of sample solution, centrifugation time, and concentration of DDTC, are optimized.

10 CFR Appendix J to Part 110 - Illustrative List of Uranium Conversion Plant Equipment and Plutonium Conversion Plant Equipment...

Code of Federal Regulations, 2010 CFR

2010-01-01

... reactors, flame tower reactors, liquid centrifuges, distillation columns and liquid-liquid extraction... to UF6 is performed by exothermic reaction with fluorine in a tower reactor. UF6 is condensed from..., flame tower reactors, liquid centrifuges, distillation columns and liquid-liquid extraction columns. Hot...

Measurement of dielectric constant of organic solvents by indigenously developed dielectric probe

NASA Astrophysics Data System (ADS)

Keshari, Ajay Kumar; Rao, J. Prabhakar; Rao, C. V. S. Brahmmananda; Ramakrishnan, R.; Ramanarayanan, R. R.

2018-04-01

The extraction, separation and purification of actinides (uranium and plutonium) from various matrices are an important step in nuclear fuel cycle. One of the separation process adopted in an industrial scale is the liquid-liquid extraction or solvent extraction. Liquid-liquid extraction uses a specific ligand/extractant in conjunction with suitable diluent. Solvent extraction or liquid-liquid extraction, involves the partitioning of the solute between two immiscible phases. In most cases, one of the phases is aqueous, and the other one is an organic solvent. The solvent used in solvent extraction should be selective for the metal of interest, it should have optimum distribution ratio, and the loaded metal from the organic phase should be easily stripped under suitable experimental conditions. Some of the important physical properties which are important for the solvent are density, viscosity, phase separation time, interfacial surface tension and the polarity of the extractant.

Preparation of magnetic chitosan and graphene oxide-functional guanidinium ionic liquid composite for the solid-phase extraction of protein.

PubMed

Ding, Xueqin; Wang, Yuzhi; Wang, Ying; Pan, Qi; Chen, Jing; Huang, Yanhua; Xu, Kaijia

2015-02-25

A series of novel cationic functional hexaalkylguanidinium ionic liquids and anionic functional tetraalkylguanidinium ionic liquids have been synthesized, and then magnetic chitosan graphene oxide (MCGO) composite has been prepared and coated with these functional guanidinium ionic liquids to extract protein by magnetic solid-phase extraction. MCGO-functional guanidinium ionic liquid has been characterized by vibrating sample magnetometer, field emission scanning electron microscopy, X-ray diffraction spectrometer and Fourier transform infrared spectrometer. After extraction, the concentrations of protein were determined by measuring the absorbance at 278 nm using an ultra violet visible spectrophotometer. The advantages of MCGO-functional guanidinium ionic liquid in protein extraction were compared with magnetic chitosan, graphene oxide, MCGO and MCGO-ordinary imidazolium ionic liquid. The proposed method has been applied to extract trypsin, lysozyme, ovalbumin and bovine serum albumin. A comprehensive study of the adsorption conditions such as the concentration of protein, the amount of MCGO-functional guanidinium ionic liquid, the pH, the temperature and the extraction time were also presented. Moreover, the MCGO-functional guanidinium ionic liquid can be easily regenerated, and the extraction capacity was about 94% of the initial one after being used three times. Copyright © 2015 Elsevier B.V. All rights reserved.

METHOD OF LIQUID-LIQUID EXTRACTION OF BLOOD SURROGATES FOR ASSESSING HUMAN EXPOSURE TO JET FUEL

EPA Science Inventory

A baseline method of liquid?liquid extraction for assessing human exposure to JP-8 jet fuel was established by extracting several representative compounds ranging from very volatile to semi-volatile organic compounds, including benzene, toluene, nonane, decane, undecane, tridec...

Design criteria for extraction with chemical reaction and liquid membrane permeation

NASA Technical Reports Server (NTRS)

Bart, H. J.; Bauer, A.; Lorbach, D.; Marr, R.

1988-01-01

The design criteria for heterogeneous chemical reactions in liquid/liquid systems formally correspond to those of classical physical extraction. More complex models are presented which describe the material exchange at the individual droplets in an extraction with chemical reaction and in liquid membrane permeation.

Ionic-liquid-impregnated resin for the microwave-assisted solid-liquid extraction of triazine herbicides in honey.

PubMed

Wu, Lijie; Song, Ying; Hu, Mingzhu; Yu, Cui; Zhang, Hanqi; Yu, Aimin; Ma, Qiang; Wang, Ziming

2015-09-01

Microwave-assisted ionic-liquid-impregnated resin solid-liquid extraction was developed for the extraction of triazine herbicides, including cyanazine, metribuzin, desmetryn, secbumeton, terbumeton, terbuthylazine, dimethametryn, and dipropetryn in honey samples. The ionic-liquid-impregnated resin was prepared by immobilizing 1-hexyl-3-methylimidazolium hexafluorophosphate in the microspores of resin. The resin was used as the extraction adsorbent. The extraction and enrichment of analytes were performed in a single step. The extraction time can be shortened greatly with the help of microwave. The effects of experimental parameters including type of resin, type of ionic liquid, mass ratio of resin to ionic liquid, extraction time, amount of the impregnated resin, extraction temperature, salt concentration, and desorption conditions on the extraction efficiency, were investigated. A Box-Behnken design was applied to the selection of the experimental parameters. The recoveries were in the range of 80.1 to 103.4% and the relative standard deviations were lower than 6.8%. The present method was applied to the analysis of honey samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optimization of an accelerated solvent extraction dispersive liquid-liquid microextraction method for the separation and determination of essential oil from Ligusticum chuanxiong Hort by gas chromatography with mass spectrometry.

PubMed

Yang, Guang; Sun, Qiushi; Hu, Zhiyan; Liu, Hua; Zhou, Tingting; Fan, Guorong

2015-10-01

In this study, an accelerated solvent extraction dispersive liquid-liquid microextraction coupled with gas chromatography and mass spectrometry was established and employed for the extraction, concentration and analysis of essential oil constituents from Ligusticum chuanxiong Hort. Response surface methodology was performed to optimize the key parameters in accelerated solvent extraction on the extraction efficiency, and key parameters in dispersive liquid-liquid microextraction were discussed as well. Two representative constituents in Ligusticum chuanxiong Hort, (Z)-ligustilide and n-butylphthalide, were quantitatively analyzed. It was shown that the qualitative result of the accelerated solvent extraction dispersive liquid-liquid microextraction approach was in good agreement with that of hydro-distillation, whereas the proposed approach took far less extraction time (30 min), consumed less plant material (usually <1 g, 0.01 g for this study) and solvent (<20 mL) than the conventional system. To sum up, the proposed method could be recommended as a new approach in the extraction and analysis of essential oil. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

10 CFR Appendix J to Part 110 - Illustrative List of Uranium Conversion Plant Equipment and Plutonium Conversion Plant Equipment...

Code of Federal Regulations, 2011 CFR

2011-01-01

... reactors, flame tower reactors, liquid centrifuges, distillation columns and liquid-liquid extraction... UF4 to UF6 is performed by exothermic reaction with fluorine in a tower reactor. UF6 is condensed from..., flame tower reactors, liquid centrifuges, distillation columns and liquid-liquid extraction columns. Hot...

Accelerated solvent extraction combined with dispersive liquid-liquid microextraction before gas chromatography with mass spectrometry for the sensitive determination of phenols in soil samples.

PubMed

Xing, Han-Zhu; Wang, Xia; Chen, Xiang-Feng; Wang, Ming-Lin; Zhao, Ru-Song

2015-05-01

A method combining accelerated solvent extraction with dispersive liquid-liquid microextraction was developed for the first time as a sample pretreatment for the rapid analysis of phenols (including phenol, m-cresol, 2,4-dichlorophenol, and 2,4,6-trichlorophenol) in soil samples. In the accelerated solvent extraction procedure, water was used as an extraction solvent, and phenols were extracted from soil samples into water. The dispersive liquid-liquid microextraction technique was then performed on the obtained aqueous solution. Important accelerated solvent extraction and dispersive liquid-liquid microextraction parameters were investigated and optimized. Under optimized conditions, the new method provided wide linearity (6.1-3080 ng/g), low limits of detection (0.06-1.83 ng/g), and excellent reproducibility (<10%) for phenols. Four real soil samples were analyzed by the proposed method to assess its applicability. Experimental results showed that the soil samples were free of our target compounds, and average recoveries were in the range of 87.9-110%. These findings indicate that accelerated solvent extraction with dispersive liquid-liquid microextraction as a sample pretreatment procedure coupled with gas chromatography and mass spectrometry is an excellent method for the rapid analysis of trace levels of phenols in environmental soil samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Extraction of ranitidine and nizatidine with using imidazolium ionic liquids prior spectrophotometric and chromatographic detection.

PubMed

Kiszkiel, Ilona; Starczewska, Barbara; Leśniewska, Barbara; Późniak, Patrycja

2015-03-15

A new extraction medium was proposed for liquid-liquid extraction of the histamine H2 receptor antagonists ranitidine (RNT) and nizatidine (NZT). The ionic liquids with low vapor pressure and favorable solvating properties for a range of compounds such as 1-butyl-3-methylimidazolium hexafluorophosphate [C4mim][PF6] and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [C4mim][Tf2N] were tested for isolation of analytes. The extraction parameters of RNT and NZT, namely, amount of ionic liquid, pH of sample solution, shaking and centrifugation time were optimized. The isolation processes were performed with 1 mL of the ionic liquids. The extracted samples (pH values near 4) were shaken at 1750 rpm. The influence of interfering substances on the efficiency of extraction process was also studied. Methods for the histamine H2 receptor antagonists (ranitidine and nizatidine) determination after their separation using imidazolium ionic liquids by high performance liquid chromatography (HPLC) combined with UV spectrophotometry were developed. The application of ionic liquids in extraction step allows for selective isolation of analytes from aqueous matrices and their preconcentration. The above methods were applied to the determination of RNT and NZT in environmental samples (river water and wastewater after treatment). Copyright © 2014 Elsevier B.V. All rights reserved.

Quantitation of the enantiomers of tramadol and its three main metabolites in human whole blood using LC-MS/MS.

PubMed

Haage, Pernilla; Kronstrand, Robert; Carlsson, Björn; Kugelberg, Fredrik C; Josefsson, Martin

2016-02-05

The analgesic drug tramadol and its metabolites are chiral compounds, with the (+)- and (-)-enantiomers showing different pharmacological and toxicological effects. This novel enantioselective method, based on LC-MS/MS in reversed phase mode, enabled measurement of the parent compound and its three main metabolites O-desmethyltramadol, N-desmethyltramadol and N,O-didesmethyltramadol simultaneously. Whole blood samples of 0.5g were fortified with internal standards (tramadol-(13)C-D3 and O-desmethyl-cis-tramadol-D6) and extracted under basic conditions (pH 11) by liquid-liquid extraction. Chromatography was performed on a chiral alpha-1-acid glycoprotein (AGP) column preceded by an AGP guard column. The mobile phase consisted of 0.8% acetonitrile and 99.2% ammonium acetate (20mM, pH 7.2). A post-column infusion with 0.05% formic acid in acetonitrile was used to enhance sensitivity. Quantitation as well as enantiomeric ratio measurements were covered by quality controls. Validation parameters for all eight enantiomers included selectivity (high), matrix effects (no ion suppression/enhancement), calibration model (linear, weight 1/X(2), in the range of 0.25-250ng/g), limit of quantitation (0.125-0.50ng/g), repeatability (2-6%) and intermediate precision (2-7%), accuracy (83-114%), dilution integrity (98-115%), carry over (not exceeding 0.07%) and stability (stable in blood and extract). The method was applied to blood samples from a healthy volunteer administrated a single 100mg dose and to a case sample concerning an impaired driver, which confirmed its applicability in human pharmacokinetic studies as well as in toxicological and forensic investigations. Copyright © 2015 Elsevier B.V. All rights reserved.

Chembio extraction on a chip by nanoliter droplet ejection.

PubMed

Yu, Hongyu; Kwon, Jae Wan; Kim, Eun Sok

2005-03-01

This paper describes a novel liquid separation technique for chembio extraction by an ultrasonic nanoliter-liquid-droplet ejector built on a PZT sheet. This technique extracts material from an aqueous two-phase system (ATPS) in a precise amount through digital control of the number of nanoliter droplets, without any mixing between the two liquids in the ATPS. The ultrasonic droplet ejector uses an acoustic streaming effect produced by an acoustic beam focused on the liquid surface, and ejects liquid droplets only from the liquid surface without disturbing most of the liquid below the surface. This unique characteristic of the focused acoustic beam is perfect (1) for separating a top-layer liquid (from the bulk of liquid) that contains particles of interest or (2) for recovering a top-layer liquid that has different phase from a bottom-layer liquid. Three kinds of liquid extraction are demonstrated with the ultrasonic droplet ejector: (1) 16 microl of top layer in Dextran-polyethylene glycol-water ATPS (aqueous two-phase system) is recovered within 20 s; (2) micron sized particles that float on water surface are ejected out with water droplets; and (3) oil layer on top of water is separated out.

Effectiveness of Liquid-Liquid Extraction, Solid Phase Extraction, and Headspace Technique for Determination of Some Volatile Water-Soluble Compounds of Rose Aromatic Water

PubMed Central

2017-01-01

Steam distillation is used to isolate scent of rose flowers. Rose aromatic water is commonly used in European cuisine and aromatherapy besides its use in cosmetic industry for its lovely scent. In this study, three different sampling techniques, liquid-liquid extraction (LLE), headspace technique (HS), and solid phase extraction (SPE), were compared for the analysis of volatile water-soluble compounds in commercial rose aromatic water. Some volatile water-soluble compounds of rose aromatic water were also analyzed by gas chromatography mass spectrometry (GCMS). In any case, it was concluded that one of the solid phase extraction methods led to higher recoveries for 2-phenylethyl alcohol (PEA) in the rose aromatic water than the liquid-liquid extraction and headspace technique. Liquid-liquid extraction method provided higher recovery ratios for citronellol, nerol, and geraniol than others. Ideal linear correlation coefficient values were observed by GCMS for quantitative analysis of volatile compounds (r2 ≥ 0.999). Optimized methods showed acceptable repeatability (RSDs < 5%) and excellent recovery (>95%). For compounds such as α-pinene, linalool, β-caryophyllene, α-humulene, methyl eugenol, and eugenol, the best recovery values were obtained with LLE and SPE. PMID:28791049

Enantioselective analysis of citalopram and escitalopram in postmortem blood together with genotyping for CYP2D6 and CYP2C19.

PubMed

Carlsson, Björn; Holmgren, Anita; Ahlner, Johan; Bengtsson, Finn

2009-03-01

Citalopram is marketed as a racemate (50:50) mixture of the S(+)-enantiomer and R(-)-enantiomer and the active S(+)-enantiomer (escitalopram) that possess inhibitory effects. Citalopram was introduced in Sweden in 1992 and is the most frequently used antidepressant to date in Sweden. In 2002, escitalopram was introduced onto the Swedish market for treatment of depression and anxiety disorders. The main objective of this study was to investigate S(+)-citalopram [i.e., the racemic drug (citalopram) or the enantiomer (escitalopram)] present in forensic autopsy cases positive for the presence of citalopram in routine screening using a non-enantioselective bioanalytical method. Fifty out of the 270 samples found positive by gas chromatography-nitrogen-phosphorus detection were further analyzed using enantioselective high-performance liquid chromatography. The 50 cases were genotyped for CYP2D6 and CYP2C19, as these isoenzymes are implicated in the metabolism of citalopram and escitalopram. In samples positive for racemic citalopram using the screening method for forensic autopsy cases, up to 20% would have been misinterpreted in the absence of an enantioselective method. An enantioselective method is thus necessary for correct interpretation of autopsy cases, after the enantiomer has been introduced onto the market. The percentage of poor metabolizers was 6% for CYP2D6 and 8% for CYP2C19.

Recovery of steroidal alkaloids from potato peels using pressurized liquid extraction.

PubMed

Hossain, Mohammad B; Rawson, Ashish; Aguiló-Aguayo, Ingrid; Brunton, Nigel P; Rai, Dilip K

2015-05-13

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.

Fast, simple and efficient supramolecular solvent-based microextraction of mecoprop and dichlorprop in soils prior to their enantioselective determination by liquid chromatography-tandem mass spectrometry.

PubMed

Caballo, C; Sicilia, M D; Rubio, S

2014-02-01

A simple, sensitive, rapid and economic method was developed for the quantification of enantiomers of chiral pesticides as mecoprop (MCPP) and dichlorprop (DCPP) in soil samples using supramolecular solvent-based microextraction (SUSME) combined with liquid chromatography coupled to mass spectrometry (LC-MS/MS). SUSME has been described for the extraction of chiral pesticides in water, but this is firstly applied to soil samples. MCPP and DCPP are herbicides widely used in agriculture that have two enantiomeric forms (R- and S-) differing in environmental fate and toxicity. Therefore, it is essential to have analytical methods for monitoring individual DCPP and MCPP enantiomers in environmental samples. MCPP and DCPP were extracted in a supramolecular solvent (SUPRAS) made up of dodecanoic acid aggregates, the extract was dried under a nitrogen stream, the two herbicides dissolved in acetate buffer and the aqueous extract directly injected in the LC-MS/MS system. The recoveries obtained were independent of soil composition and age of herbicide residues. The detection and quantitation limits of the developed method for the determination of R- and S-MCPP and R- and S-DCPP in soils were 0.03 and 0.1 ng g(-1), respectively, and the precision, expressed as relative standard deviation (n=6), for enantiomer concentrations of 5 and 100 ng g(-1) were in the ranges 4.1-6.1% and 2.9-4.1%. Recoveries for soil samples spiked with enantiomer concentrations within the interval 5-180 ng g(-1) and enantiomeric ratios (ERs) of 1, 3 and 9, ranged between 93 and 104% with standard deviations of the percent recovery varying between 0.3% and 6.0%. Because the SUPRAS can solubilize analytes through different type of interactions (dispersion, dipole-dipole and hydrogen bonds), it could be used to extract a great variety of pesticides (including both polar and non-polar) in soils. © 2013 Published by Elsevier B.V.

High enantiomeric excess of the flavor relevant 4-alkyl-branched Fatty acids in milk fat and subcutaneous adipose tissue of sheep and goat.

PubMed

Kaffarnik, Stefanie; Heid, Carolina; Kayademir, Yasemin; Eibler, Dorothee; Vetter, Walter

2015-01-21

Volatile 4-alkyl-branched fatty acids are characteristic flavor compounds of sheep and goat. Due to the methyl branch, the carbon C-4 represents a stereogenic center with the possible presence of one or both enantiomers in the respective samples. In this study, we used enantioselective gas chromatography to study the enantiomeric composition of 4-methyloctanoic acid (4-Me-8:0) and 4-ethyloctanoic acid (4-Et-8:0) in milk and dairy products from sheep and goat as well as in goat subcutaneous tissue. Different columns coated with modified cyclodextrins were tested to resolve racemic 4-alkyl-branched fatty acid methyl ester standards. The best enantiomer resolution was obtained on 25% octakis(2,3,6-tri-O-ethyl)-γ-cyclodextrin (γ-TECD) diluted in OV-1701. For analysis of the food samples, the lipids were extracted and fatty acids in the extracts were converted into fatty acid methyl esters. Non-aqueous reversed-phase high-performance liquid chromatography was used to fractionate the samples in order to gain one solution enriched in 4-Me-8:0 methyl ester and one solution enriched with 4-Et-8:0 methyl ester. Subsequent analysis by enantioselective gas chromatography with mass spectrometry allowed only the detection of one enantiomer of 4-Me-8:0 and 4-Et-8:0 in the samples. By means of a non-racemic standard of 4-Me-8:0, it was found that the predominant enantiomer was (R)-4-Me-8:0.

Extraction of organic compounds with room temperature ionic liquids.

PubMed

Poole, Colin F; Poole, Salwa K

2010-04-16

Room temperature ionic liquids are novel solvents with a rather specific blend of physical and solution properties that makes them of interest for applications in separation science. They are good solvents for a wide range of compounds in which they behave as polar solvents. Their physical properties of note that distinguish them from conventional organic solvents are a negligible vapor pressure, high thermal stability, and relatively high viscosity. They can form biphasic systems with water or low polarity organic solvents and gases suitable for use in liquid-liquid and gas-liquid partition systems. An analysis of partition coefficients for varied compounds in these systems allows characterization of solvent selectivity using the solvation parameter model, which together with spectroscopic studies of solvent effects on probe substances, results in a detailed picture of solvent behavior. These studies indicate that the solution properties of ionic liquids are similar to those of polar organic solvents. Practical applications of ionic liquids in sample preparation include extractive distillation, aqueous biphasic systems, liquid-liquid extraction, liquid-phase microextraction, supported liquid membrane extraction, matrix solvents for headspace analysis, and micellar extraction. The specific advantages and limitations of ionic liquids in these studies is discussed with a view to defining future uses and the need not to neglect the identification of new room temperature ionic liquids with physical and solution properties tailored to the needs of specific sample preparation techniques. The defining feature of the special nature of ionic liquids is not their solution or physical properties viewed separately but their unique combinations when taken together compared with traditional organic solvents. Copyright 2009 Elsevier B.V. All rights reserved.

Evaluation of two membrane-based microextraction techniques for the determination of endocrine disruptors in aqueous samples by HPLC with diode array detection.

PubMed

Luiz Oenning, Anderson; Lopes, Daniela; Neves Dias, Adriana; Merib, Josias; Carasek, Eduardo

2017-11-01

In this study, the viability of two membrane-based microextraction techniques for the determination of endocrine disruptors by high-performance liquid chromatography with diode array detection was evaluated: hollow fiber microporous membrane liquid-liquid extraction and hollow-fiber-supported dispersive liquid-liquid microextraction. The extraction efficiencies obtained for methylparaben, ethylparaben, bisphenol A, benzophenone, and 2-ethylhexyl-4-methoxycinnamate from aqueous matrices obtained using both approaches were compared and showed that hollow fiber microporous membrane liquid-liquid extraction exhibited higher extraction efficiency for most of the compounds studied. Therefore, a detailed optimization of the extraction procedure was carried out with this technique. The optimization of the extraction conditions and liquid desorption were performed by univariate analysis. The optimal conditions for the method were supported liquid membrane with 1-octanol for 10 s, sample pH 7, addition of 15% w/v of NaCl, extraction time of 30 min, and liquid desorption in 150 μL of acetonitrile/methanol (50:50 v/v) for 5 min. The linear correlation coefficients were higher than 0.9936. The limits of detection were 0.5-4.6 μg/L and the limits of quantification were 2-16 μg/L. The analyte relative recoveries were 67-116%, and the relative standard deviations were less than 15.5%. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of a dispersive liquid-liquid microextraction method using a lighter-than-water ionic liquid for the analysis of polycyclic aromatic hydrocarbons in water.

PubMed

Medina, Giselle S; Reta, Mario

2016-11-01

A dispersive liquid-liquid microextraction method using a lighter-than-water phosphonium-based ionic liquid for the extraction of 16 polycyclic aromatic hydrocarbons from water samples has been developed. The extracted compounds were analyzed by liquid chromatography coupled to fluorescence/diode array detectors. The effects of several experimental parameters on the extraction efficiency, such as type and volume of ionic liquid and disperser solvent, type and concentration of salt in the aqueous phase and extraction time, were investigated and optimized. Three phosphonium-based ionic liquids were assayed, obtaining larger extraction efficiencies when trihexyl-(tetradecyl)phosphonium bromide was used. The optimized methodology requires a few microliters of a lighter-than-water phosphonium-based ionic liquid, which allows an easy separation of the extraction solvent phase. The obtained limits of detection were between 0.02 and 0.56 μg/L, enrichment factors between 109 and 228, recoveries between 60 and 108%, trueness between 0.4 and 9.9% and reproducibility values between 3 and 12% were obtained. These figures of merit combined with the simplicity, rapidity and low cost of the analytical methodology indicate that this is a viable and convenient alternative to the methods reported in the literature. The developed method was used to analyze polycyclic aromatic hydrocarbons in river water samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of sudan dyes in red wine and fruit juice using ionic liquid-based liquid-liquid microextraction and high-performance liquid chromatography.

PubMed

Sun, Shuo; Wang, Ying; Yu, Wenzhi; Zhao, Tianqi; Gao, Shiqian; Kang, Mingqin; Zhang, Yupu; Zhang, Hanqi; Yu, Yong

2011-07-01

The liquid-liquid microextraction (LLME) was developed for extracting sudan dyes from red wine and fruit juice. Room temperature ionic liquid was used as the extraction solvent. The target analytes were determined by high-performance liquid chromatography. The extraction parameters were optimized. The optimal conditions are as follows: volume of [C(6)MIM][PF(6)] 50 μL; the extraction time 10 min; pH value of the sample solution 7.0; NaCl concentration in sample solution 5%. The extraction recoveries for the analytes in red wine and fruit samples are 86.79-108.28 and 68.54-85.66%, whereas RSDs are 1.42-5.12 and 1.43-6.19%, respectively. The limits of detection and quantification were 0.428 and 1.426 ng/mL for sudan I, 0.938 and 3.127 ng/mL for sudan II, 1.334 and 4.445 ng/mL for sudan III, 1.454 and 4.846 ng/mL for sudan IV, respectively. Compared with conventional liquid-liquid extraction (CLLE) and ultrasonic extraction (UE), when LLME was applied, the sample amount was less (LLME: 4 mL; CLLE: 10 mL; UE: 10 mL), the extraction time was shorter (LLME: 15 min; CLLE: 110 min; UE: 50 min) and the extraction solvent amount was less (LLME: 0.05 mL IL; CLLE: 15 mL hexane; UE: 20 mL hexane). The proposed method offers a simple, rapid and efficient sample preparation for determining sudan dyes in red wine and fruit juice samples. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ionic Liquid Droplet Microreactor for Catalysis Reactions Not at Equilibrium.

PubMed

Zhang, Ming; Ettelaie, Rammile; Yan, Tao; Zhang, Suojiang; Cheng, Fangqin; Binks, Bernard P; Yang, Hengquan

2017-12-06

We develop a novel strategy to more effectively and controllably process continuous enzymatic or homogeneous catalysis reactions based on nonaqueous Pickering emulsions. A key element of this strategy is "bottom-up" construction of a macroscale continuous flow reaction system through packing catalyst-containing micron-sized ionic liquid (IL) droplet in oil in a column reactor. Due to the continuous influx of reactants into the droplet microreactors and the continuous release of products from the droplet microreactors, catalysis reactions in such a system can take place without limitations arising from establishment of the reaction equilibrium and catalyst separation, inherent in conventional batch reactions. As proof of the concept, enzymatic enantioselective trans-esterification and CuI-catalyzed cycloaddition reactions using this IL droplet-based flow system both exhibit 8 to 25-fold enhancement in catalysis efficiency compared to their batch counterparts, and a durability of at least 4000 h for the enantioselective trans-esterification of 1-phenylethyl alcohol, otherwise unattainable in their batch counterparts. We further establish a theoretical model for such a catalysis system working under nonequilibrium conditions, which not only supports the experimental results but also helps to predict reaction progress at a microscale level. Being operationally simple, efficient, and adaptive, this strategy provides an unprecedented platform for practical applications of enzymes and homogeneous catalysts even at a controllable level.

Enantioseparation of Imazalil and Monitoring of Its Enantioselective Degradation in Apples and Soils Using Ultrahigh-Performance Liquid Chromatography-Tandem Mass Spectrometry.

PubMed

Li, Runan; Dong, Fengshou; Xu, Jun; Liu, Xingang; Wu, Xiaohu; Pan, Xinglu; Tao, Yan; Chen, Zenglong; Zheng, Yongquan

2017-04-26

Imazalil is a widely used systemic chiral fungicide that is still being employed as a racemic mixture without distinguishing the difference between enantiomers, which often leads to its inaccurate risk assessment. In this study, a robust and highly sensitive chiral separation method was developed for imazalil enantiomers by ultrahigh-performance liquid chromatography-tandem mass spectrometry and was further applied to study the degradation dynamics of imazalil enantiomers in apples and field soils at three sites in China. The baseline enantioseparation for imazalil was achieved within 3.5 min on a Lux Cellulose-2 (CCMPC) column with acetonitrile (ACN)/water (65:35, v/v) with a mobile phase at 0.5 mL/min flow rate and a column temperature of 20 °C. The limit of quantitation (LOQ) for each enantiomer was <0.60 μg/kg, with a baseline resolution of approximately 1.75. The research showed that (S)-(+)-imazalil degraded more rapidly than (R)-(-)-imazalil in Gala apples, whereas (R)-(-)-imazalil preferentially degraded in Golden Delicious apples. No significant enantioselectivity was observed in OBIR-2T-47 apples and field soils from the three sites. Results of this study provide useful references for risk assessment and the rational use of imazalil in further agricultural produce practice.

Enantioselective bioaccumulation of diniconazole in Tenebrio molitor larvae.

PubMed

Liu, Chen; LV, Xiao Tian; Zhu, Wen Xue; QU, Hao Yang; Gao, Yong Xin; Guo, Bao Yuan; Wang, Hui Li

2013-12-01

The enantioselective bioaccumulation of diniconazole in Tenebrio molitor Linne larva was investigated with liquid chromatography tandem mass spectrometry based on the ChiralcelOD-3R[cellulose tri-(3,5-dimethylphenyl carbamate)] column. In this study we documented the effects of dietary supplementation with wheat bran contaminated by racemic diniconazole at two dose levels of 20 mg kg(-1) and 2 mg kg(-1) (dry weight) in Tenebrio molitor. The results showed that both doses of diniconazole were taken up by Tenebrio molitor rapidly in the first few days, the concentrations of R-enantiomer and S-enantiomer at high doses reached the highest level of 0.55 mg kg(-1) and 0.48 mg kg(-1) , respectively, on the 1(st) d, and the concentrations of them obtained a maxima of 0.129 mg kg(-1) and 0.128 mg kg(-1) at low dose, respectively, on the 3(rd) d, which means that the concentration of diniconazole was proportional to the time of achieving the highest accumulated level. It afterwards attained equilibrium after a sharp decline at both 20 mg kg(-1) and 2 mg kg(-1) of diniconazole. The determination results from the feces of Tenebrio molitor demonstrated that the extraction recovery (ER) values of the high dose group were higher than that of the low dose group and the values were all above 1; therefore, it could be inferred that enantiomerization existed in Tenebrio molitor. Additionally, the biota accumulation factor was used to evaluate the bioaccumulation of diniconazole enantiomers, showing that the bioaccumulation of diniconazole in Tenebrio molitor was enantioselective with preferential accumulation of S-enantiomer. © 2013 Wiley Periodicals, Inc.

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

PubMed

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

Removal of actinide elements from liquid scintillation cocktail wastes using liquid-liquid extraction and demulsification techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Foltz, K.; Landsberger, S.; Srinivasan, B.

1994-12-31

A method for the separation of radionuclides with Z greater than 88, from lower-level radioactive wastes (liquid scintillation cocktail or LSC wastes), is described. The method is liquid-liquid extraction (LLX) and demulsification. The actinide elements are removed from the LSC wastes by extraction into an aqueous phase after the cocktail has been demulsified. The aqueous and organic phases are separated, then the wastes type remaining may be incinerated. Future experiments will be performed to study the effects of pH and temperature and to extend the study to wastes containing americium.

OPTIMIZED DETERMINATION OF TRACE JET FUEL VOLATILE ORGANIC COMPOUNDS IN HUMAN BLOOD USING IN-FIELD LIQUID-LIQUID EXTRACTION WITH SUBSEQUENT LABORATORY GAS CHROMATOGRAPHIC-MASS SPECTROMETRIC ANALYSIS AND ON-COLUMN LARGE VOLUME INJECTION

EPA Science Inventory

A practical and sensitive method to assess volatile organic compounds (VOCs) from JP-8 jet fuel in human whole blood was developed by modifying previously established liquid-liquid extraction procedures, optimizing extraction times, solvent volume, specific sample processing te...

A simple and selective method for determination of phthalate biomarkers in vegetable samples by high pressure liquid chromatography-electrospray ionization-tandem mass spectrometry.

PubMed

Zhou, Xi; Cui, Kunyan; Zeng, Feng; Li, Shoucong; Zeng, Zunxiang

2016-06-01

In the present study, solid-phase extraction cartridges including silica reversed-phase Isolute C18, polymeric reversed-phase Oasis HLB and mixed-mode anion-exchange Oasis MAX, and liquid-liquid extractions with ethyl acetate, n-hexane, dichloromethane and its mixtures were compared for clean-up of phthalate monoesters from vegetable samples. Best recoveries and minimised matrix effects were achieved using ethyl acetate/n-hexane liquid-liquid extraction for these target compounds. A simple and selective method, based on sample preparation by ultrasonic extraction and liquid-liquid extraction clean-up, for the determination of phthalate monoesters in vegetable samples by liquid chromatography/electrospray ionisation-tandem mass spectrometry was developed. The method detection limits for phthalate monoesters ranged from 0.013 to 0.120 ng g(-1). Good linearity (r(2)>0.991) between MQLs and 1000× MQLs was achieved. The intra- and inter-day relative standard deviation values were less than 11.8%. The method was successfully used to determine phthalate monoester metabolites in the vegetable samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

Superbase-derived protic ionic liquid extractants for metal ion separation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bell, Jason R.; Dai, Sheng; Luo, Huimin

2014-04-19

Solvent extraction of La 3+ and Ba 2+ by an ionic liquid extractant in an imidazolium-based ionic liquid diluent was investigated. Seven protic ionic liquid extractants were examined and these protic ILs are based on five organic superbases and either 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octadione (Hfod) or 1,1,1,5,5,5-hexafluoroacetylacetone (Hhfac) -diketones as anion. For fod-based extractants, the extraction efficiencies and separation factors were found to be concentration dependent. The effects of aqueous phase acidity, extractant structure, and extractant concentration on separation properties of La 3+ and Ba 2+ are discussed in this paper.

Physical-Chemical Properties of the Chiral Fungicide Fenamidone and Strategies for Enantioselective Crystallization.

PubMed

Kort, Anne-Kathleen; Lorenz, Heike; Seidel-Morgenstern, Andreas

2016-06-01

Thermodynamic and kinetic parameters are of prime importance for designing crystallization processes. In this article, Preferential Crystallization, as a special approach to carry out enantioselective crystallization, is described to resolve the enantiomers of the chiral fungicide fenamidone. In preliminary investigations the melting behavior and solid-liquid equilibria in the presence of solvents were quantified. The analyses revealed a stable solid phase behavior of fenamidone in the applied solvents. Based on the results obtained, a two-step crystallization route was designed and realized capable of providing highly pure enantiomers. An initial Preferential Crystallization of the racemate was performed prior to crystallizing the target enantiomer preferentially out of the enriched mother liquor. Chirality 28:514-520, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Bidentate urea-based chiral selectors for enantioselective high performance liquid chromatography: synthesis and evaluation of "Crab-like" stationary phases.

PubMed

Kotoni, Dorina; Villani, Claudio; Bell, David S; Capitani, Donatella; Campiglia, Pietro; Gasparrini, Francesco

2013-07-05

A rational approach for the design and preparation of two new "Crab-like" totally synthetic, brush-type chiral stationary phases is presented. Enantiopure diamines, namely 1,2-diaminocyclohexane and 1,2-diphenyl-1,2-ethylene-diamine were treated with 3-(triethoxysilyl)propyl isocyanate, to yield reactive ureido selectors that were eventually attached to unmodified silica particles through a stable, bidentate tether, through a facile two-step one-pot procedure. A full chemical characterization of the new materials has been obtained through solid-state NMR (both (29)Si and (13)C CPMAS) spectroscopy. Columns packed with the two Crab-like chiral stationary phases allow for different mechanisms of separation: normal phase liquid chromatography, reversed phase liquid chromatography and polar organic mode and show a high stability at basic pH values. In particular, the Crab-like column containing the 1,2-diphenyl-1,2-ethylene-diamine selector proved a promising candidate for the resolution of a wide range of racemates (including benzodiazepines, N-derivatized amino acids, and free carboxylic acids) both in normal phase and polar organic mode. An Hmin of 9.57 at a μsf of 0.80mm/s (corresponding to 0.8mL/min) was obtained through van Deemter analysis, based on toluene, for the Crab-like column with the 1,2-diphenyl-1,2-ethylene-diamine selector (250mm×4.6mm I.D.), with a calculated reduced height equivalent to a theoretical plate (h) of only 1.91. Finally, comparative studies were performed with a polymeric commercially available P-CAP-DP column in order to evaluate enantioselectivity and resolution of the Crab-like columns. Copyright © 2013 Elsevier B.V. All rights reserved.

A green deep eutectic solvent dispersive liquid-liquid micro-extraction (DES-DLLME) for the UHPLC-PDA determination of oxyprenylated phenylpropanoids in olive, soy, peanuts, corn, and sunflower oil.

PubMed

Ferrone, Vincenzo; Genovese, Salvatore; Carlucci, Maura; Tiecco, Matteo; Germani, Raimondo; Preziuso, Francesca; Epifano, Francesco; Carlucci, Giuseppe; Taddeo, Vito Alessandro

2018-04-15

A green dispersive liquid-liquid microextraction (DLLME) using deep eutectic solvent (DES) as the extracting solvent has been developed and applied for the simultaneous quantification of ferulic acid, umbelliferone, boropinic acid, 7-isopentenyloxycoumarin, 4'-geranyloxyferulic acid (GOFA), and auraptene in some vegetable oils using ultra high performance liquid chromatography (UHPLC) with photodiode array detection (PDA). All parameters in the extraction step, including selection and loading of both extracting and dispersing solvents, amount of both extractant and disperser solvent were investigated and optimized. PhAA/TMG DES achieved higher recovery and enrichment factor compared to other DESs. The validated method showed good linearity with correlation coefficients, r 2 >0.9990 for all the analytes. Furthermore, this is the first time that eco-friendly solvents are used for the extraction of oxyprenylated phenylpropanoids and the corresponding extract analyzed with ultra high performance liquid chromatography with photodiode array detection. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

PubMed Central

Zu, Ge; Zhang, Rongrui; Yang, Lei; Ma, Chunhui; Zu, Yuangang; Wang, Wenjie; Zhao, Chunjian

2012-01-01

Ionic liquid based, ultrasound-assisted extraction was successfully applied to the extraction of phenolcarboxylic acids, carnosic acid and rosmarinic acid, from Rosmarinus officinalis. Eight ionic liquids, with different cations and anions, were investigated in this work and [C8mim]Br was selected as the optimal solvent. Ultrasound extraction parameters, including soaking time, solid–liquid ratio, ultrasound power and time, and the number of extraction cycles, were discussed by single factor experiments and the main influence factors were optimized by response surface methodology. The proposed approach was demonstrated as having higher efficiency, shorter extraction time and as a new alternative for the extraction of carnosic acid and rosmarinic acid from R. officinalis compared with traditional reference extraction methods. Ionic liquids are considered to be green solvents, in the ultrasound-assisted extraction of key chemicals from medicinal plants, and show great potential. PMID:23109836

Microwave-assisted ionic liquid homogeneous liquid-liquid microextraction coupled with high performance liquid chromatography for the determination of anthraquinones in Rheum palmatum L.

PubMed

Wang, Zhibing; Hu, Jianxue; Du, Hongxia; He, Shuang; Li, Qing; Zhang, Hanqi

2016-06-05

The microwave-assisted ionic liquid homogeneous liquid-liquid microextraction (MA-IL-HLLME) coupled with high performance liquid chromatography with diode array detection (HPLC-DAD) was developed for the determination of anthraquinones, including aloe-emodin, emodin, chrysophanol and physcion in root of Rheum palmatum L. Several experimental parameters influencing the extraction efficiency, including amount of sample, type and volume of ionic liquid, volume and pH value of extraction medium, microwave power and extraction time, concentration of NH4PF6 as well as centrifugal condition were optimized. When 140μL of ionic liquid ([C8MIM][BF4]) was used as an extraction solvent, target analytes can be extracted from sample matrix in one minute with the help of microwave irradiation. The MA-IL-HLLME is simple and quick. The calibration curves exhibited good linear relationship (r>0.9984). The limits of detection and quantification were in the range of 0.015-0.026 and 0.051-0.088μgmL(-1), respectively. The spiked recovery for each analyte was in the range of 81.13-93.07% with relative standard deviations lower than 6.89%. The present method is free of volatile organic solvents, and represents lower expenditures of sample, extraction time and solvent, compared with ultrasonic and heat reflux extraction. The results indicated that the present method can be successfully applied to the determination of anthraquinones in medicinal plant. Copyright © 2016 Elsevier B.V. All rights reserved.

Predictive model for ionic liquid extraction solvents for rare earth elements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grabda, Mariusz; Oleszek, Sylwia; Institute of Environmental Engineering of the Polish Academy of Sciences, ul. M. Sklodowskiej-Curie 34, 41-819, Zabrze

2015-12-31

The purpose of our study was to select the most effective ionic liquid extraction solvents for dysprosium (III) fluoride using a theoretical approach. Conductor-like Screening Model for Real Solvents (COSMO-RS), based on quantum chemistry and the statistical thermodynamics of predefined DyF{sub 3}-ionic liquid systems, was applied to reach the target. Chemical potentials of the salt were predicted in 4,400 different ionic liquids. On the base of these predictions set of ionic liquids’ ions, manifesting significant decrease of the chemical potentials, were selected. Considering the calculated physicochemical properties (hydrophobicity, viscosity) of the ionic liquids containing these specific ions, the most effectivemore » extraction solvents for liquid-liquid extraction of DyF{sub 3} were proposed. The obtained results indicate that the COSMO-RS approach can be applied to quickly screen the affinity of any rare earth element for a large number of ionic liquid systems, before extensive experimental tests.« less

Comparison of salting-out and sugaring-out liquid-liquid extraction methods for the partition of 10-hydroxy-2-decenoic acid in royal jelly and their co-extracted protein content.

PubMed

Tu, Xijuan; Sun, Fanyi; Wu, Siyuan; Liu, Weiyi; Gao, Zhaosheng; Huang, Shaokang; Chen, Wenbin

2018-01-15

Homogeneous liquid-liquid extraction (h-LLE) has been receiving considerable attention as a sample preparation method due to its simple and fast partition of compounds with a wide range of polarities. To better understand the differences between the two h-LLE extraction approaches, salting-out assisted liquid-liquid extraction (SALLE) and sugaring-out assisted liquid-liquid extraction (SULLE), have been compared for the partition of 10-hydroxy-2-decenoic acid (10-HDA) from royal jelly, and for the co-extraction of proteins. Effects of the amount of phase partition agents and the concentration of acetonitrile (ACN) on the h-LLE were discussed. Results showed that partition efficiency of 10-HDA depends on the phase ratio in both SALLE and SULLE. Though the partition triggered by NaCl and glucose is less efficient than MgSO 4 in the 50% (v/v) ACN-water mixture, their extraction yields can be improved to be similar with that in MgSO 4 SALLE by increasing the initial concentration of ACN in the ACN-water mixture. The content of co-extracted protein was correlated with water concentration in the obtained upper phase. MgSO 4 showed the largest protein co-extraction at the low concentration of salt. Glucose exhibited a large protein co-extraction in the high phase ratio condition. Furthermore, NaCl with high initial ACN concentration is recommended because it produced high extraction yield for 10-HDA and the lowest amount of co-extracted protein. These observations would be valuable for the sample preparation of royal jelly. Copyright © 2017 Elsevier B.V. All rights reserved.

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.

PubMed

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.

Membrane contactor assisted extraction/reaction process employing ionic liquids

DOEpatents

Lin, Yupo J [Naperville, IL; Snyder, Seth W [Lincolnwood, IL

2012-02-07

The present invention relates to a functionalized membrane contactor extraction/reaction system and method for extracting target species from multi-phase solutions utilizing ionic liquids. One preferred embodiment of the invented method and system relates to an extraction/reaction system wherein the ionic liquid extraction solutions act as both extraction solutions and reaction mediums, and allow simultaneous separation/reactions not possible with prior art technology.

REDISTRIBUTOR FOR LIQUID-LIQUID EXTRACTION COLUMNS

DOEpatents

Bradley, J.G.

1957-10-29

An improved baffle plate construction to intimately mix immiscible liquid solvents for solvent extraction processes in a liquid-liquid pulse column is described. To prevent the light and heavy liquids from forming separate continuous homogeneous vertical channels through sections of the column, a baffle having radially placed rectangular louvers with deflection plates opening upon alternate sides of the baffle is placed in the column, normal to the axis. This improvement substantially completely reduces strippiig losses due to poor mixing.

Liquid-liquid extraction assisted by a carbon nanoparticles interface. Electrophoretic determination of atrazine in environmental samples.

PubMed

Caballero-Díaz, Encarnación; Simonet, Bartolomé; Valcárcel, Miguel

2013-10-21

A novel method for the determination of atrazine, using liquid-liquid extraction assisted by a nanoparticles film formed in situ and composed of organic solvent stabilized-carbon nanoparticles, is described. The presence of nanoparticles located at the liquid-liquid interface reinforced the extraction of analyte from matrix prior to capillary electrophoresis (CE) analysis. Some influential experimental variables were optimized in order to enhance the extraction efficiency. The developed procedure confirmed that carbon nanoparticles, especially multi-walled carbon nanotubes, are suitable to be used in sample treatment processes introducing new mechanisms of interaction with the analyte. The application of the proposed preconcentration method followed by CE detection enabled the determination of atrazine in spiked river water providing acceptable RSD values (11.6%) and good recoveries (about 87.0-92.0%). Additionally, a similar extraction scheme was tested in soil matrices with a view to further applications in real soil samples.

Optimization of squalene produced from crude palm oil waste

NASA Astrophysics Data System (ADS)

Wandira, Irda; Legowo, Evita H.; Widiputri, Diah I.

2017-01-01

Squalene is a hydrocarbon originally and still mostly extracted from shark liver oil. Due to environmental issues over shark hunting, there have been efforts to extract squalene from alternative sources, such as Palm Fatty Acid Distillate (PFAD), one of crude palm oil (CPO) wastes. Previous researches have shown that squalene can be extracted from PFAD using saponification process followed with liquid-liquid extraction process although the method had yet to be optimized in order to optimize the amount of squalene extracted from PFAD. The optimization was done by optimizing both processes of squalene extraction method: saponification and liquid-liquid extraction. The factors utilized in the saponification process optimization were KOH concentration and saponification duration while during the liquid-liquid extraction (LLE) process optimization, the factors used were the volumes of distilled water and dichloromethane. The optimum percentage of squalene content in the extract (24.08%) was achieved by saponifying the PFAD with 50%w/v KOH for 60 minutes and subjecting the saponified PFAD to LLE, utilizing 100 ml of distilled water along with 3 times addition of fresh dichloromethane, 75 ml each; those factors would be utilized in the optimum squalene extraction method.

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

PubMed

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

2016-01-15

A new approach for ionic liquid based enzyme-assisted extraction (ILEAE) of chlorogenic acid (CGA) from Eucommia ulmoides is presented in which enzyme pretreatment was used in ionic liquids aqueous media to enhance extraction yield. For this purpose, the solubility of CGA and the activity of cellulase were investigated in eight 1-alkyl-3-methylimidazolium ionic liquids. Cellulase in 0.5 M [C6mim]Br aqueous solution was found to provide better performance in extraction. The factors of ILEAE procedures including extraction time, extraction phase pH, extraction temperatures and enzyme concentrations were investigated. Moreover, the novel developed approach offered advantages in term of yield and efficiency compared with other conventional extraction techniques. Scanning electronic microscopy of plant samples indicated that cellulase treated cell wall in ionic liquid solution was subjected to extract, which led to more efficient extraction by reducing mass transfer barrier. The proposed ILEAE method would develope a continuous process for enzyme-assisted extraction including enzyme incubation and solvent extraction process. In this research, we propose a novel view for enzyme-assisted extraction of plant active component, besides concentrating on enzyme facilitated cell wall degradation, focusing on improvement of bad permeability of ionic liquids solutions. Copyright © 2015 Elsevier B.V. All rights reserved.

Literature Review: Crud Formation at the Liquid/Liquid Interface of TBP-Based Solvent-Extraction Processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Delegard, Calvin H.; Casella, Amanda J.

2016-09-30

This report summarizes the literature reviewed on crud formation at the liquid:liquid interface of solvent extraction processes. The review is focused both on classic PUREX extraction for industrial reprocessing, especially as practiced at the Hanford Site, and for those steps specific to plutonium purification that were used at the Plutonium Reclamation Facility (PRF) within the Plutonium Finishing Plant (PFP) at the Hanford Site.

A Guided Inquiry Liquid/Liquid Extractions Laboratory for Introductory Organic Chemistry

ERIC Educational Resources Information Center

Raydo, Margaret L.; Church, Megan S.; Taylor, Zane W.; Taylor, Christopher E.; Danowitz, Amy M.

2015-01-01

A guided inquiry laboratory experiment for teaching liquid/liquid extractions to first semester undergraduate organic chemistry students is described. This laboratory is particularly useful for introductory students as the analytes that are separated are highly colored dye molecules. This allows students to track into which phase each analyte…

Infrared absorption spectroscopy characterization of liquid-solid interfaces: The case of chiral modification of catalysts

NASA Astrophysics Data System (ADS)

Zaera, Francisco

2018-03-01

An overview is provided here of our work on the characterization of chiral modifiers for the bestowing of enantioselectivity to metal-based hydrogenation catalysts, with specific reference to the so-called Orito reaction. We start with a brief discussion of the use of infrared absorption spectroscopy (IR) for the characterization of chemical species at liquid-solid interfaces, describing the options available as well as the information that can be extracted from such experiments and the advantages and disadvantages associated with the technique. We then summarize the main results that we have reported to date from our IR study of the adsorption of cinchona alkaloids and related compounds from solutions onto platinum surfaces. Several observations are highlighted and placed in context in terms of the existing knowledge and their relevance to catalysis. Key conclusions include the uniqueness of the nature of the adsorbed species when in the presence of the solvent (versus when the uptake is done under vacuum, or versus the pure or dissolved molecules), the fact that each modifier adopts unique and distinct adsorption geometries on the surface and that those change with the concentration of the solution in ways that correlate well with the performance of the catalyst, the potential tendency of at least some of these chiral modifiers to bind to the surface primarily via the nitrogen atom of the amine group, not the aromatic ring as it is often assumed, and the observation that the ability of one modifier to dominate the catalytic chemistry in solutions containing mixtures of two or more of those is linked to their capacity for displacing each other from the surface, which in turn is determined by a balance between the strength of their binding to the surface and their solubility in the liquid solvent.

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

PubMed

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

2017-10-06

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

Homogeneous Liquid–Liquid Extraction of Rare Earths with the Betaine—Betainium Bis(trifluoromethylsulfonyl)imide Ionic Liquid System

PubMed Central

Hoogerstraete, Tom Vander; Onghena, Bieke; Binnemans, Koen

2013-01-01

Several fundamental extraction parameters such as the kinetics and loading were studied for a new type of metal solvent extraction system with ionic liquids. The binary mixture of the ionic liquid betainium bis(trifluoromethylsulfonyl)imide and water shows thermomorphic behavior with an upper critical solution temperature (UCST), which can be used to avoid the slower mass transfer due to the generally higher viscosity of ionic liquids. A less viscous homogeneous phase and mixing on a molecular scale are obtained when the mixture is heated up above 55 °C. The influence of the temperature, the heating and cooling times, were studied for the extraction of neodymium(III) with betaine. A plausible and equal extraction mechanism is proposed in bis(trifluoromethylsulfonyl)imide, nitrate, and chloride media. After stripping of the metals from the ionic liquid phase, a higher recovery of the ionic liquid was obtained by salting-out of the ionic liquid fraction lost by dissolution in the aqueous phase. The change of the upper critical solution temperature by the addition of HCl or betaine was investigated. In addition, the viscosity was measured below and above the UCST as a function of the temperature. PMID:24169434

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

PubMed Central

Quan, Ji; Hu, Zeshu

2018-01-01

Food safety issues closely related to human health have always received widespread attention from the world society. As a basic food source, wheat is the fundamental support of human survival; therefore, the detection of pesticide residues in wheat is very necessary. In this work, the ultrasonic-assisted ionic liquid-dispersive liquid-liquid microextraction (DLLME) method was firstly proposed, and the extraction and analysis of three organophosphorus pesticides were carried out by combining high-performance liquid chromatography (HPLC). The extraction efficiencies of three ionic liquids with bis(trifluoromethylsulfonyl)imide (Tf2N) anion were compared by extracting organophosphorus in wheat samples. It was found that the use of 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([OMIM][Tf2N]) had both high enrichment efficiency and appropriate extraction recovery. Finally, the method was used for the determination of three wheat samples, and the recoveries of them were 74.8–112.5%, 71.8–104.5%, and 83.8–115.5%, respectively. The results show that the method proposed is simple, fast, and efficient, which can be applied to the extraction of organic matters in wheat samples. PMID:29854562

Liquid microjunction surface sampling coupled with high-pressure liquid chromatography-electrospray ionization-mass spectrometry for analysis of drugs and metabolites in whole-body thin tissue sections.

PubMed

Kertesz, Vilmos; Van Berkel, Gary J

2010-07-15

In this work, a commercially available autosampler was adapted to perform direct liquid microjunction (LMJ) surface sampling followed by a high-pressure liquid chromatography (HPLC) separation of the extract components and detection with electrospray ionization mass spectrometry (ESI-MS). To illustrate the utility of coupling a separation with this direct liquid extraction based surface sampling approach, four different organs (brain, lung, kidney, and liver) from whole-body thin tissue sections of propranolol dosed and control mice were examined. The parent drug was observed in the chromatograms of the surface sampling extracts from all the organs of the dosed mouse examined. In addition, two isomeric phase II metabolites of propranolol (an aliphatic and an aromatic hydroxypropranolol glucuronide) were observed in the chromatograms of the extracts from lung, kidney, and liver. Confirming the presence of one or the other or both of these glucuronides in the extract from the various organs was not possible without the separation. These drug and metabolite data obtained using the LMJ surface sampling/HPLC-MS method and the results achieved by analyzing similar samples by conventional extraction of the tissues and subsequent HPLC-MS analysis were consistent. The ability to directly and efficiently sample from thin tissue sections via a liquid extraction and then perform a subsequent liquid phase separation increases the utility of this liquid extraction surface sampling approach.

A novel liquid/liquid extraction process composed of surfactant and acetonitrile for purification of polygalacturonase enzyme from Durio zibethinus.

PubMed

Amid, Mehrnoush; Manap, Yazid; Azmira, Farhana; Hussin, Muhaini; Sarker, Zaidul Islam

2015-07-01

Polygalacturonase is one of the important enzymes used in various industries such as food, detergent, pharmaceutical, textile, pulp and paper. A novel liquid/liquid extraction process composed of surfactant and acetonitrile was employed for the first time to purify polygalacturonase from Durio zibethinus. The influences of different parameters such as type and concentration of surfactants, concentrations of acetonitrile and composition of surfactant/acetonitrile on partitioning behavior and recovery of polygalacturonase was investigated. Moreover, the effect of pH of system and crude load on purification fold and yield of purified polygalacturonase were studied. The results of the experiment indicated the polygalacturonase was partitioned into surfactant top rich phase with impurities being partitioned into acetonitrile bottom rich phase in the novel method of liquid/liquid process composed of 23% (w/w) Triton X-100 and 19% (w/w) acetonitrile, at 55.6% of TLL (tie line length) crude load of 25% (w/w) at pH 6.0. Recovery and recycling of components also was measured in each successive step of liquid/liquid extraction process. The enzyme was successfully recovered by the method with a high purification factor of 14.3 and yield of 97.3% while phase components were also recovered and recycled above 95%. This study demonstrated that the novel method of liquid/liquid extraction process can be used as an efficient and economical extraction method rather than the traditional methods of extraction for the purification and recovery of the valuable enzyme. Copyright © 2015 Elsevier B.V. All rights reserved.

Dispersive liquid-liquid microextraction of phenolic compounds from vegetable oils using a magnetic ionic liquid.

PubMed

Zhu, Shuqiang; Wang, Lijun; Su, Along; Zhang, Haixia

2017-08-01

A novel method was developed for the determination of two endocrine-disrupting chemicals, bisphenol A and 4-nonylphenol, in vegetable oil by dispersive liquid-liquid microextraction followed by ultra high performance liquid chromatography with tandem mass spectrometry. Using a magnetic liquid as the microextraction solvent, several key parameters were optimized, including the type and volume of the magnetic liquid, extraction time, amount of dispersant, and the type of reverse extractant. The detection limits for bisphenol A and 4-nonylphenol were 0.1 and 0.06 μg/kg, respectively. The recoveries were 70.4-112.3%, and the relative standard deviations were less than 4.2%. The method is simple for the extraction of bisphenol A and 4-nonylphenol from vegetable oil and suitable for routine analysis. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nicotine Levels and Presence of Selected Tobacco-Derived Toxins in Tobacco Flavoured Electronic Cigarette Refill Liquids

PubMed Central

Farsalinos, Konstantinos E.; Gillman, I. Gene; Melvin, Matt S.; Paolantonio, Amelia R.; Gardow, Wendy J.; Humphries, Kathy E.; Brown, Sherri E.; Poulas, Konstantinos; Voudris, Vassilis

2015-01-01

Background. Some electronic cigarette (EC) liquids of tobacco flavour contain extracts of cured tobacco leaves produced by a process of solvent extraction and steeping. These are commonly called Natural Extract of Tobacco (NET) liquids. The purpose of the study was to evaluate nicotine levels and the presence of tobacco-derived toxins in tobacco-flavoured conventional and NET liquids. Methods. Twenty-one samples (10 conventional and 11 NET liquids) were obtained from the US and Greek market. Nicotine levels were measured and compared with labelled values. The levels of tobacco-derived chemicals were compared with literature data on tobacco products. Results. Twelve samples had nicotine levels within 10% of the labelled value. Inconsistency ranged from −21% to 22.1%, with no difference observed between conventional and NET liquids. Tobacco-specific nitrosamines (TSNAs) were present in all samples at ng/mL levels. Nitrates were present almost exclusively in NET liquids. Acetaldehyde was present predominantly in conventional liquids while formaldehyde was detected in almost all EC liquids at trace levels. Phenols were present in trace amounts, mostly in NET liquids. Total TSNAs and nitrate, which are derived from the tobacco plant, were present at levels 200–300 times lower in 1 mL of NET liquids compared to 1 gram of tobacco products. Conclusions. NET liquids contained higher levels of phenols and nitrates, but lower levels of acetaldehyde compared to conventional EC liquids. The lower levels of tobacco-derived toxins found in NET liquids compared to tobacco products indicate that the extraction process used to make these products did not transfer a significant amount of toxins to the NET. Overall, all EC liquids contained far lower (by 2–3 orders of magnitude) levels of the tobacco-derived toxins compared to tobacco products. PMID:25811768

Nicotine levels and presence of selected tobacco-derived toxins in tobacco flavoured electronic cigarette refill liquids.

PubMed

Farsalinos, Konstantinos E; Gillman, I Gene; Melvin, Matt S; Paolantonio, Amelia R; Gardow, Wendy J; Humphries, Kathy E; Brown, Sherri E; Poulas, Konstantinos; Voudris, Vassilis

2015-03-24

Some electronic cigarette (EC) liquids of tobacco flavour contain extracts of cured tobacco leaves produced by a process of solvent extraction and steeping. These are commonly called Natural Extract of Tobacco (NET) liquids. The purpose of the study was to evaluate nicotine levels and the presence of tobacco-derived toxins in tobacco-flavoured conventional and NET liquids. Twenty-one samples (10 conventional and 11 NET liquids) were obtained from the US and Greek market. Nicotine levels were measured and compared with labelled values. The levels of tobacco-derived chemicals were compared with literature data on tobacco products. Twelve samples had nicotine levels within 10% of the labelled value. Inconsistency ranged from -21% to 22.1%, with no difference observed between conventional and NET liquids. Tobacco-specific nitrosamines (TSNAs) were present in all samples at ng/mL levels. Nitrates were present almost exclusively in NET liquids. Acetaldehyde was present predominantly in conventional liquids while formaldehyde was detected in almost all EC liquids at trace levels. Phenols were present in trace amounts, mostly in NET liquids. Total TSNAs and nitrate, which are derived from the tobacco plant, were present at levels 200-300 times lower in 1 mL of NET liquids compared to 1 gram of tobacco products. NET liquids contained higher levels of phenols and nitrates, but lower levels of acetaldehyde compared to conventional EC liquids. The lower levels of tobacco-derived toxins found in NET liquids compared to tobacco products indicate that the extraction process used to make these products did not transfer a significant amount of toxins to the NET. Overall, all EC liquids contained far lower (by 2-3 orders of magnitude) levels of the tobacco-derived toxins compared to tobacco products.

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

PubMed

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.

Selective Solid-liquid Extraction and Liquid-liquid Extraction of Lithium Chloride using Strapped Calix[4]pyrroles

DOE PAGES

He, Qing; Williams, Neil J.; Oh, Ju; ...

2018-05-25

LiCl is a classic "hard" ion salt that is present in lithium-rich brines and a key component in end-of-life materials (i.e., used lithium-ion batteries). Its isolation and purification from like salts is a recognized challenge with potential strategic and economic implications. Here in this paper, we describe two ditopic calix[4]pyrrole-based ion pair receptors (2 and 3), that are capable of selectively capturing LiCl. Under solid-liquid extraction conditions, using 2 as the extractant, LiCl could be separated from a NaCl-KCl salt mixture containing as little as 1% LiCl with ~100% selectivity, while receptor 3 achieved similar separations when the LiCl levelmore » was as low as 200 ppm. Under liquid-liquid extraction conditions using nitrobenzene as the non-aqueous phase, the extraction preference displayed by 2 is KCl > NaCl > LiCl. Lastly, in contrast, 3 exhibits high selectivity towards LiCl over NaCl and KCl, with no appreciable extraction being observed for the latter two salts.« less

Fast and comprehensive analysis of secondary metabolites in cocoa products using ultra high-performance liquid chromatography directly after pressurized liquid extraction.

PubMed

Damm, Irina; Enger, Eileen; Chrubasik-Hausmann, Sigrun; Schieber, Andreas; Zimmermann, Benno F

2016-08-01

Fast methods for the extraction and analysis of various secondary metabolites from cocoa products were developed and optimized regarding speed and separation efficiency. Extraction by pressurized liquid extraction is automated and the extracts are analyzed by rapid reversed-phase ultra high-performance liquid chromatography and normal-phase high-performance liquid chromatography methods. After extraction, no further sample treatment is required before chromatographic analysis. The analytes comprise monomeric and oligomeric flavanols, flavonols, methylxanthins, N-phenylpropenoyl amino acids, and phenolic acids. Polyphenols and N-phenylpropenoyl amino acids are separated in a single run of 33 min, procyanidins are analyzed by normal-phase high-performance liquid chromatography within 16 min, and methylxanthins require only 6 min total run time. A fourth method is suitable for phenolic acids, but only protocatechuic acid was found in relevant quantities. The optimized methods were validated and applied to 27 dark chocolates, one milk chocolate, two cocoa powders and two food supplements based on cocoa extract. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Selective Solid-liquid Extraction and Liquid-liquid Extraction of Lithium Chloride using Strapped Calix[4]pyrroles

DOE Office of Scientific and Technical Information (OSTI.GOV)

He, Qing; Williams, Neil J.; Oh, Ju

LiCl is a classic "hard" ion salt that is present in lithium-rich brines and a key component in end-of-life materials (i.e., used lithium-ion batteries). Its isolation and purification from like salts is a recognized challenge with potential strategic and economic implications. Here in this paper, we describe two ditopic calix[4]pyrrole-based ion pair receptors (2 and 3), that are capable of selectively capturing LiCl. Under solid-liquid extraction conditions, using 2 as the extractant, LiCl could be separated from a NaCl-KCl salt mixture containing as little as 1% LiCl with ~100% selectivity, while receptor 3 achieved similar separations when the LiCl levelmore » was as low as 200 ppm. Under liquid-liquid extraction conditions using nitrobenzene as the non-aqueous phase, the extraction preference displayed by 2 is KCl > NaCl > LiCl. Lastly, in contrast, 3 exhibits high selectivity towards LiCl over NaCl and KCl, with no appreciable extraction being observed for the latter two salts.« less

Ionic liquid foam floatation coupled with ionic liquid dispersive liquid-liquid microextraction for the separation and determination of estrogens in water samples by high-performance liquid chromatography with fluorescence detection.

PubMed

Zhang, Rui; Wang, Chuanliu; Yue, Qiaohong; Zhou, Tiecheng; Li, Na; Zhang, Hanqi; Hao, Xiaoke

2014-11-01

An ionic liquid foam floatation coupled with ionic liquid dispersive liquid-liquid microextraction method was proposed for the extraction and concentration of 17-α-estradiol, 17-β-estradiol-benzoate, and quinestrol in environmental water samples by high-performance liquid chromatography with fluorescence detection. 1-Hexyl-3-methylimidazolium tetrafluoroborate was applied as foaming agent in the foam flotation process and dispersive solvent in microextraction. The introduction of the ion-pairing and salting-out agent NH4 PF6 was beneficial to the improvement of recoveries for the hydrophobic ionic liquid phase and analytes. Parameters of the proposed method including concentration of 1-hexyl-3-methylimidazolium tetrafluoroborate, flow rate of carrier gas, floatation time, types and concentration of ionic liquids, salt concentration in samples, extraction time, and centrifugation time were evaluated. The recoveries were between 98 and 105% with relative standard deviations lower than 7% for lake water and well water samples. The isolation of the target compounds from the water was found to be efficient, and the enrichment factors ranged from 4445 to 4632. This developing method is free of volatile organic solvents compared with regular extraction. Based on the unique properties of ionic liquids, the application of foam floatation, and dispersive liquid-liquid microextraction was widened. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

PubMed

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

PubMed

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.

Rapid analysis of ultraviolet filters using dispersive liquid-liquid microextraction coupled to headspace gas chromatography and mass spectrometry.

PubMed

Pierson, Stephen A; Trujillo-Rodríguez, María J; Anderson, Jared L

2018-05-29

An ionic-liquid-based in situ dispersive liquid-liquid microextraction method coupled to headspace gas chromatography and mass spectrometry was developed for the rapid analysis of ultraviolet filters. The chemical structures of five ionic liquids were specifically designed to incorporate various functional groups for the favorable extraction of the target analytes. Extraction parameters including ionic liquid mass, molar ratio of ionic liquid to metathesis reagent, vortex time, ionic strength, pH, and total sample volume were studied and optimized. The effect of the headspace temperature and volume during the headspace sampling step was also evaluated to increase the sensitivity of the method. The optimized procedure is fast as it only required ∼7-10 min per extraction and allowed for multiple extractions to be performed simultaneously. In addition, the method exhibited high precision, good linearity, and low limits of detection for six ultraviolet filters in aqueous samples. The developed method was applied to both pool and lake water samples attaining acceptable relative recovery values. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Use of liquid/supercritical CO2 extraction process for butanol recovery from fermentation broth

USDA-ARS?s Scientific Manuscript database

In order for butanol fermentation to be a viable option, it is essential to recover it from fermentation broth using economical alternate in-situ product recovery techniques such as liquid/supercritical CO2 extraction as compared to distillation. This technique (liquid CO2 extraction & supercritical...

Screening of commercial and pecan shell-extracted liquid smoke agents as natural antimicrobials against foodborne pathogens.

PubMed

Van Loo, Ellen J; Babu, D; Crandall, Philip G; Ricke, Steven C

2012-06-01

Liquid smoke extracts have traditionally been used as flavoring agents, are known to possess antioxidant properties, and serve as natural alternatives to conventional antimicrobials. The antimicrobial efficacies of commercial liquid smoke samples may vary depending on their source and composition and the methods used to extract and concentrate the smoke. We investigated the MICs of eight commercial liquid smoke samples against Salmonella Enteritidis, Staphylococcus aureus, and Escherichia coli . The commercial liquid smoke samples purchased were supplied by the manufacturer as water-based or concentrated extracts of smoke from different wood sources. The MICs of the commercial smokes to inhibit the growth of foodborne pathogens ranged from 0.5 to 6.0% for E. coli, 0.5 to 8.0% for Salmonella, and 0.38 to 6% for S. aureus. The MIC for each liquid smoke sample was similar in its effect on both E. coli and Salmonella. Solvent-extracted antimicrobials prepared using pecan shells displayed significant differences between their inhibitory concentrations depending on the type of solvent used for extraction. The results indicated that the liquid smoke samples tested in this study could serve as effective natural antimicrobials and that their inhibitory effects depended more on the solvents used for extraction than the wood source.

Solvent extraction separation of Th-227 and Ac-225 in room temperature ionic liquids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bell, Jason R; Boll, Rose Ann; Dai, Sheng

2012-01-01

The solvent extractions of Th-227 and Ac-225 from the aqueous phase into ionic liquids (ILs) were investigated by using N,N,N ,N - tetraoctyldiglycolamide (TODGA) or di(2-ethylhexyl)phosphoric acid (HDEHP) as an extractant. Four ionic liquids, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C4mim][NTf2]), 1-butyl-3-methylimidazolium bis(perfluoroethanesulfonyl)imide ([C4mim][BETI]), 1-butyl-2,3-trimethyleneimidazolium (trifluoromethanesulfonyl)imide [BuI5][NTf2], and 1-benzyl pyridinium bis(trifluoromethanesulfonyl)imide ([PhCH2Py][NTf2]) were used as extraction solvents for separation of Th-227 and Ac-225 in this study. Excellent extraction efficiencies and selectivities were found for Th-227/Ac-225 when HDEHP was used as an extractant in these ionic liquids. The effects of different extractant concentrations in ionic liquids and acidities of the aqueous phase on extraction efficienciesmore » and selectivities of Th-227/Ac-225 are also presented in this article.« less

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

PubMed

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

2018-01-15

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

Multiple functional ionic liquids based dispersive liquid-liquid microextraction combined with high performance chromatography for the determination of phenolic compounds in water samples.

PubMed

Sun, Jian-Nan; Chen, Juan; Shi, Yan-Ping

2014-07-01

A new mode of ionic liquid based dispersive liquid-liquid microextraction (IL-DLLME) is developed. In this work, [C6MIm][PF6] was chosen as the extraction solvent, and two kinds of hydrophilic ionic liquids, [EMIm][BF4] and [BSO3HMIm][OTf], functioned as the dispersive solvent. So in the whole extraction procedure, no organic solvent was used. With the aid of SO3H group, the acidic compound was extracted from the sample solution without pH adjustment. Two phenolic compounds, namely, 2-naphthol and 4-nitrophenol were chosen as the target analytes. Important parameters affecting the extraction efficiency, such as the type of hydrophilic ionic liquids, the volume ratio of [EMIm][BF4] to [BSO3HMIm][OTf], type and volume of extraction solvent, pH value of sample solution, sonication time, extraction time and centrifugation time were investigated and optimized. Under the optimized extraction conditions, the method exhibited good sensitivity with the limits of detection (LODs) at 5.5 μg L(-1)and 10.0 μg L(-1) for 4-nitrophenol and 2-naphthol, respectively. Good linearity over the concentration ranges of 24-384 μg L(-1) for 4-nitrophenol and 28-336 μg L(-1) for 2-naphthol was obtained with correlation coefficients of 0.9998 and 0.9961, respectively. The proposed method can directly extract acidic compound from environmental sample or even more complex sample matrix without any pH adjustment procedure. Copyright © 2014 Elsevier B.V. All rights reserved.

Sensitive spectrophotometric determination of Co(II) using dispersive liquid-liquid micro-extraction method in soil samples.

PubMed

Hasanpour, Foroozan; Hadadzadeh, Hassan; Taei, Masoumeh; Nekouei, Mohsen; Mozafari, Elmira

2016-05-01

Analytical performance of conventional spectrophotometer was developed by coupling of effective dispersive liquid-liquid micro-extraction method with spectrophotometric determination for ultra-trace determination of cobalt. The method was based on the formation of Co(II)-alpha-benzoin oxime complex and its extraction using a dispersive liquid-liquid micro-extraction technique. During the present work, several important variables such as pH, ligand concentration, amount and type of dispersive, and extracting solvent were optimized. It was found that the crucial factor for the Co(II)-alpha benzoin oxime complex formation is the pH of the alkaline alcoholic medium. Under the optimized condition, the calibration graph was linear in the ranges of 1.0-110 μg L(-1) with the detection limit (S/N = 3) of 0.5 μg L(-1). The preconcentration operation of 25 mL of sample gave enhancement factor of 75. The proposed method was applied for determination of Co(II) in soil samples.

Rational approach to solvent system selection for liquid-liquid extraction-assisted sample pretreatment in counter-current chromatography.

PubMed

Wang, Jiajia; Gu, Dongyu; Wang, Miao; Guo, Xinfeng; Li, Haoquan; Dong, Yue; Guo, Hong; Wang, Yi; Fan, Mengqi; Yang, Yi

2017-05-15

A rational liquid-liquid extraction approach was established to pre-treat samples for high-speed counter-current chromatography (HSCCC). n-Hexane-ethyl acetate-methanol-water (4:5:4:5, v/v) and (1:5:1:5, v/v) were selected as solvent systems for liquid-liquid extraction by systematically screening K of target compounds to remove low- and high-polarity impurities in the sample, respectively. After liquid-liquid extraction was performed, 1.4g of crude sample II was obtained from 18.5g of crude sample I which was extracted from the flowers of Robinia pseudoacacia L., and then separated with HSCCC by using a solvent system composed of n-hexane-ethyl acetate-methanol-water (1:2:1:2, v/v). As a result, 31mg of robinin and 37mg of kaempferol 7-O-α-l-rhamnopyranoside were isolated from 200mg of crude sample II in a single run of HSCCC. A scale-up separation was also performed, and 160mg of robinin with 95% purity and 188mg of kaempferol 7-O-α-l-rhamnopyranoside with 97% purity were produced from 1.2g of crude sample II. Copyright © 2017 Elsevier B.V. All rights reserved.

Enantioselective cyclization of racemic supramolecular polymers.

PubMed

ten Cate, A Tessa; Dankers, Patricia Y W; Kooijman, Huub; Spek, Anthony L; Sijbesma, Rint P; Meijer, E W

2003-06-11

Homochiral hydrogen-bonded cyclic assemblies are formed in dilute solutions of racemic supramolecular polymers based on the quadruple hydrogen bonding 2-ureido-4[1H]-pyrimidinone unit, as observed by 1H NMR and SEC experiments. Preorganization of the monomers and the combined binding strength of the eight hydrogen bonds result in a very high stability of the cyclic aggregates with pronounced selectivity between homochiral and heterochiral cyclic species, usually only observed in crystalline or liquid crystalline phases.

Investigation of heterogeneous asymmetric dihydroxylation over OsO{sub 4}-(QN){sub 2}PHAL catalysts of functionalized bimodal mesoporous silica with ionic liquid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qiu, Shenjie; Sun, Jihong, E-mail: jhsun@bjut.edu.cn; Li, Yuzhen

2011-08-15

Highlights: {yields} Functionalized bimodal mesoporous silica with MTMSPIm{sup +}Cl{sup -}. {yields} Mesoporous catalyst immobilized with OsO{sub 4}-(QN){sub 2}PHAL. {yields} Catalysts for asymmetric dihydroxylation reaction with high yield and enatioselectivity. {yields} Recyclable catalysts. -- Abstract: A novel synthesis of the functionalized bimodal mesoporous silica with ionic liquid (FBMMs) was performed. After grafting 1-methyl-3-(trimethoxysilyl)propylimidazolium chloride onto the surface of bimodal mesoporous silicas, 1,4-bis(9-O-quininyl)phthalazine ((QN){sub 2}-PHAL) and K{sub 2}Os(OH){sub 4}.2H{sub 2}O were immobilized onto the modified FBMMs by adsorption or ionic exchange methods, and then, the asymmetric dihydroxylation reaction was carried out by using solid catalysts. Techniques such as X-ray diffraction, Fourier Transformmore » Infrared spectroscopy, N{sub 2} adsorption and desorption were employed to characterize their structure and properties. The results showed that the mesoporous ordering degree of bimodal mesoporous silica decreased after functionalization and immobilization of OsO{sub 4}-(QN){sub 2}PHAL. Being very effective in asymmetric dihydroxylation with high yield and enantioselectivity, the prepared heterogeneous solid catalyst could be recycled for five times with little loss of enantioselectivity, with comparison of those results obtained in homophase system. Moreover, the effect of Osmium catalyst on asymmetric dihydroxylation was investigated.« less

Amino acid ionic liquids as chiral ligands in ligand-exchange chiral separations.

PubMed

Liu, Qian; Wu, Kangkang; Tang, Fei; Yao, Lihua; Yang, Fei; Nie, Zhou; Yao, Shouzhuo

2009-09-28

Recently, amino acid ionic liquids (AAILs) have attracted much research interest. In this paper, we present the first application of AAILs in chiral separation based on the chiral ligand exchange principle. By using 1-alkyl-3-methylimidazolium L-proline (L-Pro) as a chiral ligand coordinated with copper(II), four pairs of underivatized amino acid enantiomers-dl-phenylalanine (dl-Phe), dl-histidine (dl-His), dl-tryptophane (dl-Trp), and dl-tyrosine (dl-Tyr)-were successfully separated in two major chiral separation techniques, HPLC and capillary electrophoresis (CE), with higher enantioselectivity than conventionally used amino acid ligands (resolution (R(s))=3.26-10.81 for HPLC; R(s)=1.34-4.27 for CE). Interestingly, increasing the alkyl chain length of the AAIL cation remarkably enhanced the enantioselectivity. It was inferred that the alkylmethylimidazolium cations and L-Pro form ion pairs on the surface of the stationary phase or on the inner surface of the capillary. The ternary copper complexes with L-Pro are consequently attached to the support surface, thus inducing an ion-exchange type of retention for the dl-enantiomers. Therefore, the AAIL cation plays an essential role in the separation. This work demonstrates that AAILs are good alternatives to conventional amino acid ligands for ligand-exchange-based chiral separation. It also reveals the tremendous application potential of this new type of task-specific ILs.

Application of an efficient strategy based on liquid-liquid extraction, high-speed counter-current chromatography, and preparative HPLC for the rapid enrichment, separation, and purification of four anthraquinones from Rheum tanguticum.

PubMed

Chen, Tao; Liu, Yongling; Zou, Denglang; Chen, Chen; You, Jinmao; Zhou, Guoying; Sun, Jing; Li, Yulin

2014-01-01

This study presents an efficient strategy based on liquid-liquid extraction, high-speed counter-current chromatography, and preparative HPLC for the rapid enrichment, separation, and purification of four anthraquinones from Rheum tanguticum. A new solvent system composed of petroleum ether/ethyl acetate/water (4:2:1, v/v/v) was developed for the liquid-liquid extraction of the crude extract from R. tanguticum. As a result, emodin, aloe-emodin, physcion, and chrysophanol were greatly enriched in the organic layer. In addition, an efficient method was successfully established to separate and purify the above anthraquinones by high-speed counter-current chromatography and preparative HPLC. This study supplies a new alternative method for the rapid enrichment, separation, and purification of emodin, aloe-emodin, physcione, and chrysophanol. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

LIQUID-LIQUID EXTRACTION COLUMNS

DOEpatents

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.

Inorganic selenium speciation analysis in Allium and Brassica vegetables by ionic liquid assisted liquid-liquid microextraction with multivariate optimization.

PubMed

Castro Grijalba, Alexander; Martinis, Estefanía M; Wuilloud, Rodolfo G

2017-03-15

A highly sensitive vortex assisted liquid-liquid microextraction (VA-LLME) method was developed for inorganic Se [Se(IV) and Se(VI)] speciation analysis in Allium and Brassica vegetables. Trihexyl(tetradecyl)phosphonium decanoate phosphonium ionic liquid (IL) was applied for the extraction of Se(IV)-ammonium pyrrolidine dithiocarbamate (APDC) complex followed by Se determination with electrothermal atomic absorption spectrometry. A complete optimization of the graphite furnace temperature program was developed for accurate determination of Se in the IL-enriched extracts and multivariate statistical optimization was performed to define the conditions for the highest extraction efficiency. Significant factors of IL-VA-LLME method were sample volume, extraction pH, extraction time and APDC concentration. High extraction efficiency (90%), a 100-fold preconcentration factor and a detection limit of 5.0ng/L were achieved. The high sensitivity obtained with preconcentration and the non-chromatographic separation of inorganic Se species in complex matrix samples such as garlic, onion, leek, broccoli and cauliflower, are the main advantages of IL-VA-LLME. Copyright © 2016 Elsevier Ltd. All rights reserved.

Determination of sedative hypnotics in sewage sludge by pressurized liquid extraction with high-performance liquid chromatography and tandem mass spectrometry.

PubMed

Arbeláez, Paula; Granados, Judith; Borrull, Francesc; Marcé, Rosa Maria; Pocurull, Eva

2014-12-01

This paper describes a method for the determination of eight sedative hypnotics (benzodiazepines and barbiturates) in sewage sludge using pressurized liquid extraction and liquid chromatography with tandem mass spectrometry. Pressurized liquid extraction operating conditions were optimized and maximum recoveries were reached using methanol under the following operational conditions: 100ºC, 1500 psi, extraction time of 5 min, one extraction cycle, flush volume of 60% and purge time of 120 s. Pressurized liquid extraction recoveries were higher than 88% for all the compounds except for carbamazepine (55%). The repeatability and reproducibility between days, expressed as relative standard deviation (n = 5), were lower than 6 and 10%, respectively. The detection limits for all compounds were lower than 12.5 μg/kg of dry weight. The method was applied to determine benzodiazepines and barbiturates in sewage sludge from urban sewage treatment plants, and carbamazepine showed the highest concentration (7.9-18.9 μg/kg dry weight). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of sulfonamide antibiotics and metabolites in liver, muscle and kidney samples by pressurized liquid extraction or ultrasound-assisted extraction followed by liquid chromatography-quadrupole linear ion trap-tandem mass spectrometry (HPLC-QqLIT-MS/MS).

PubMed

Hoff, Rodrigo Barcellos; Pizzolato, Tânia Mara; Peralba, Maria do Carmo Ruaro; Díaz-Cruz, M Silvia; Barceló, Damià

2015-03-01

Sulfonamides are widely used in human and veterinary medicine. The presence of sulfonamides residues in food is an issue of great concern. Throughout the present work, a method for the targeted analysis of 16 sulfonamides and metabolites residue in liver of several species has been developed and validated. Extraction and clean-up has been statistically optimized using central composite design experiments. Two extraction methods have been developed, validated and compared: i) pressurized liquid extraction, in which samples were defatted with hexane and subsequently extracted with acetonitrile and ii) ultrasound-assisted extraction with acetonitrile and further liquid-liquid extraction with hexane. Extracts have been analyzed by liquid chromatography-quadrupole linear ion trap-tandem mass spectrometry. Validation procedure has been based on the Commission Decision 2002/657/EC and included the assessment of parameters such as decision limit (CCα), detection capability (CCβ), sensitivity, selectivity, accuracy and precision. Method׳s performance has been satisfactory, with CCα values within the range of 111.2-161.4 µg kg(-1), limits of detection of 10 µg kg(-1) and accuracy values around 100% for all compounds. Copyright © 2014 Elsevier B.V. All rights reserved.

Laboratory Production of Lemon Liqueur (Limoncello) by Conventional Maceration and a Two-Syringe System to Illustrate Rapid Solid-Liquid Dynamic Extraction

ERIC Educational Resources Information Center

Naviglio, Daniele; Montesano, Domenico; Gallo, Monica

2015-01-01

Two experimental techniques of solid-liquid extraction are compared relating to the lab-scale production of lemon liqueur, most commonly named "limoncello"; the first is the official method of maceration for the solid-liquid extraction of analytes and is widely used to extract active ingredients from a great variety of natural products;…

Selective extraction and separation of oxymatrine from Sophora flavescens Ait. extract by silica-confined ionic liquid.

PubMed

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

2012-01-01

This study highlighted the application of a two-stepped extraction method for extraction and separation of oxymatrine from Sophora flavescens Ait. extract by utilizing silica-confined ionic liquids as sorbent. The optimized silica-confined ionic liquid was firstly mixed with plant extract to adsorb oxymatrine. Simultaneously, some interference, such as matrine, was removed. The obtained suspension was then added to a cartridge for solid phase extraction. Through these two steps, target compound was adequately separated from interferences with 93.4% recovery. In comparison with traditional solid phase extraction, this method accelerates loading and reduces the use of organic solvents during washing. Moreover, the optimization of loading volume was simplified as optimization of solid/liquid ratio. Copyright © 2011 Elsevier B.V. All rights reserved.

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

PubMed

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.

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

PubMed

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.

Dispersive liquid-liquid microextraction combined with microwave-assisted derivatization for determining lipoic acid and its metabolites in human urine.

PubMed

Tsai, Chia-Ju; Chen, Yen-Ling; Feng, Chia-Hsien

2013-10-04

This study explored dispersive liquid-liquid microextraction for extraction and concentration of lipoic acid in human urine. To improve the detection of lipoic acid by both capillary liquid chromatography (CapLC) with UV detection and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), microwave-assisted derivatization with 4-bromomethyl-6,7-dimethoxycoumarin was performed to render lipoic acid chromophores for UV detection and also high ionization efficiency in MALDI. All parameters that affected lipoic acid extraction and derivatization from urine were investigated and optimized. In the analyses of human urine samples, the two methods had a linear range of 0.1-20 μM with a correlation coefficient of 0.999. The detection limits of CapLC-UV and MALDI-TOF MS were 0.03 and 0.02 μM (S/N ≧ 3), respectively. The major metabolites of lipoic acid, including 6,8-bismethylthio-octanoic acid, 4,6-bismethylthio-hexanoic acid, and 2,4-bismethylthio-butanoic acid were also extracted by dispersive liquid-liquid microextraction and detected by MALDI-TOF MS. The minor metabolites (undetectable by MALDI-TOF MS), bisnorlipoic acid and tetranorlipoic acid were also extracted by dispersive liquid-liquid microextraction and identified with an LTQ Orbitrap mass spectrometer. After dispersive liquid-liquid microextraction and microwave-assisted derivatization, all lipoic acid derivatizations and metabolites were structurally confirmed by LTQ Orbitrap. Copyright © 2013 Elsevier B.V. All rights reserved.

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

PubMed

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

2011-11-30

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

Process to upgrade coal liquids by extraction prior to hydrodenitrogenation

DOEpatents

Schneider, Abraham; Hollstein, Elmer J.; Janoski, Edward J.; Scheibel, Edward G.

1982-01-01

Oxygen compounds are removed, e.g., by extraction, from a coal liquid prior to its hydrogenation. As a result, compared to hydrogenation of such a non-treated coal liquid, the rate of nitrogen removal is increased.

Liquid CO2 extraction of Jasminum grandiflorum and comparison with conventional processes.

PubMed

Prakash, Om; Sahoo, Deeptanjali; Rout, Prasant Kumar

2012-01-01

The concrete (0.35%) of Jasminum grandiflorum L. flowers was prepared by extraction in n-pentane, and the absolute (0.27%) by fractionation of the n-pentane extract (concrete) with cold methanol. Direct extraction of flowers with liquid CO2 gave a relatively fat-free product in 0.26% yield. The liquid CO2 extract was enriched with terpenoids and benzenoids, thus providing the organoleptically accepted product. The major compounds, such as benzyl acetate, (E,E)-alpha-farnesene and (Z)-3-hexenyl benzoate, along with compounds like indole, methyl anthranilate, (Z)-jasmone, (Z)-methyl jasmonoate and (Z)-methyl epi-jasmonoate, are responsible for the high diffusivity of the jasmine fragrance. These compounds have been obtained with improved recoveries in the liquid CO2 extract. On the other hand, the yield of the essential oil was poor (0.05%), and some polar compounds (oxygenated terpenoids) were recovered in less amounts in comparison with either the n-pentane or liquid CO2 extract.

Ionic liquid-based ultrasonic/microwave-assisted extraction combined with UPLC-MS-MS for the determination of tannins in Galla chinensis.

PubMed

Lu, Chunxia; Wang, Hongxin; Lv, Wenping; Ma, Chaoyang; Lou, Zaixiang; Xie, Jun; Liu, Bo

2012-01-01

Ionic liquid was used as extraction solvents and applied to the extraction of tannins from Galla chinensis in the simultaneous ultrasonic- and microwave-assisted extraction (UMAE) technique. Several parameters of UMAE were optimised, and the results were compared with of the conventional extraction techniques. Under optimal conditions, the content of tannins was 630.2 ± 12.1 mg g⁻¹. Compared with the conventional heat-reflux extraction, maceration extraction, regular ultrasound- and microwave-assisted extraction, the proposed approach exhibited higher efficiency (11.7-22.0% enhanced) and shorter extraction time (from 6 h to 1 min). The tannins were then identified by ultraperformance liquid chromatography tandem mass spectrometry. This study suggests that ionic liquid-based UMAE is an efficient, rapid, simple and green sample preparation technique.

Hydrogen, lithium, and lithium hydride production

DOEpatents

Brown, Sam W.; Spencer, Larry S.; Phillips, Michael R.; Powell, G. Louis; Campbell, Peggy J.

2017-06-20

A method is provided for extracting hydrogen from lithium hydride. The method includes (a) heating lithium hydride to form liquid-phase lithium hydride; (b) extracting hydrogen from the liquid-phase lithium hydride, leaving residual liquid-phase lithium metal; (c) hydriding the residual liquid-phase lithium metal to form refined lithium hydride; and repeating steps (a) and (b) on the refined lithium hydride.

Quantitative Analysis of Tetramethylenedisulfotetramine ("Tetramine") Spiked into Beverages by Liquid Chromatography Tandem Mass Spectrometry with Validation by Gas Chromatography Mass Spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Owens, J; Hok, S; Alcaraz, A

Tetramethylenedisulfotetramine, commonly known as tetramine, is a highly neurotoxic rodenticide (human oral LD{sub 50} = 0.1 mg/kg) used in hundreds of deliberate food poisoning events in China. Here we describe a method for quantitation of tetramine spiked into beverages, including milk, juice, tea, cola, and water and cleaned up by C8 solid phase extraction and liquid-liquid extraction. Quantitation by high performance liquid chromatography tandem mass spectrometry (LC/MS/MS) was based upon fragmentation of m/z 347 to m/z 268. The method was validated by gas chromatography mass spectrometry (GC/MS) operated in SIM mode for ions m/z 212, 240, and 360. The limitmore » of quantitation was 0.10 {micro}g/mL by LC/MS/MS versus 0.15 {micro}g/mL for GC/MS. Fortifications of the beverages at 2.5 {micro}g/mL and 0.25 {micro}g/mL were recovered ranging from 73-128% by liquid-liquid extraction for GC/MS analysis, 13-96% by SPE and 10-101% by liquid-liquid extraction for LC/MS/MS analysis.« less

Preconcentration and determination of ceftazidime in real samples using dispersive liquid-liquid microextraction and high-performance liquid chromatography with the aid of experimental design.

PubMed

Razmi, Rasoul; Shahpari, Behrouz; Pourbasheer, Eslam; Boustanifar, Mohammad Hasan; Azari, Zhila; Ebadi, Amin

2016-11-01

A rapid and simple method for the extraction and preconcentration of ceftazidime in aqueous samples has been developed using dispersive liquid-liquid microextraction followed by high-performance liquid chromatography analysis. The extraction parameters, such as the volume of extraction solvent and disperser solvent, salt effect, sample volume, centrifuge rate, centrifuge time, extraction time, and temperature in the dispersive liquid-liquid microextraction process, were studied and optimized with the experimental design methods. Firstly, for the preliminary screening of the parameters the taguchi design was used and then, the fractional factorial design was used for significant factors optimization. At the optimum conditions, the calibration curves for ceftazidime indicated good linearity over the range of 0.001-10 μg/mL with correlation coefficients higher than the 0.98, and the limits of detection were 0.13 and 0.17 ng/mL, for water and urine samples, respectively. The proposed method successfully employed to determine ceftazidime in water and urine samples and good agreement between the experimental data and predictive values has been achieved. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Vortex-assisted liquid-liquid microextraction for the rapid screening of short-chain chlorinated paraffins in water.

PubMed

Chang, Chia-Yu; Chung, Wu-Hsun; Ding, Wang-Hsien

2016-01-01

The rapid screening of trace levels of short-chain chlorinated paraffins in various aqueous samples was performed by a simple and reliable procedure based on vortex-assisted liquid-liquid microextraction combined with gas chromatography and electron capture negative ionization mass spectrometry. The optimal vortex-assisted liquid-liquid microextraction conditions for 20 mL water sample were as follows: extractant 400 μL of dichloromethane; vortex extraction time of 1 min at 2500 × g; centrifugation of 3 min at 5000 × g; and no ionic strength adjustment. Under the optimum conditions, the limit of quantitation was 0.05 μg/L. Precision, as indicated by relative standard deviations, was less than 9% for both intra- and inter-day analysis. Accuracy, expressed as the mean extraction recovery, was above 91%. The vortex-assisted liquid-liquid microextraction with gas chromatography and electron capture negative ionization mass spectrometry method was successfully applied to quantitatively extract short-chain chlorinated paraffins from samples of river water and the effluent of a wastewater treatment plant, and the concentrations ranged from 0.8 to 1.6 μg/L. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Advances in the analysis of biological samples using ionic liquids.

PubMed

Clark, Kevin D; Trujillo-Rodríguez, María J; Anderson, Jared L

2018-02-12

Ionic liquids are a class of solvents and materials that hold great promise in bioanalytical chemistry. Task-specific ionic liquids have recently been designed for the selective extraction, separation, and detection of proteins, peptides, nucleic acids, and other physiologically relevant analytes from complex biological samples. To facilitate rapid bioanalysis, ionic liquids have been integrated in miniaturized and automated procedures. Bioanalytical separations have also benefited from the modification of nonspecific magnetic materials with ionic liquids or the implementation of ionic liquids with inherent magnetic properties. Furthermore, the direct detection of the extracted molecules in the analytical instrument has been demonstrated with structurally tuned ionic liquids and magnetic ionic liquids, providing a significant advantage in the analysis of low-abundance analytes. This article gives an overview of these advances that involve the application of ionic liquids and derivatives in bioanalysis. Graphical abstract Ionic liquids, magnetic ionic liquids, and ionic liquid-based sorbents are increasing the speed, selectivity, and sensitivity in the analysis of biological samples.

Automation of liquid-liquid extraction-spectrophotometry using prolonged pseudo-liquid drops and handheld CCD for speciation of Cr(VI) and Cr(III) in water samples.

PubMed

Chen, Wen; Zhong, Guanping; Zhou, Zaide; Wu, Peng; Hou, Xiandeng

2005-10-01

A simple spectrophotometric system, based on a prolonged pseudo-liquid drop device as an optical cell and a handheld charge coupled device (CCD) as a detector, was constructed for automatic liquid-liquid extraction and spectrophotometric speciation of trace Cr(VI) and Cr(III) in water samples. A tungsten halogen lamp was used as the light source, and a laboratory-constructed T-tube with two open ends was used to form the prolonged pseudo-liquid drop inside the tube. In the medium of perchloric acid solution, Cr(VI) reacted with 1,5-diphenylcarbazide (DPC); the formed complex was automatically extracted into n-pentanol, with a preconcentration ratio of about 5. The organic phase with extracted chromium complex was then pumped through the optical cell for absorbance measurement at 548 nm. Under optimal conditions, the calibration curve was linear in the range of 7.5 - 350 microg L(-1), with a correlation coefficient of 0.9993. The limit of detection (3sigma) was 7.5 microg L(-1). That Cr(III) species cannot react with DPC, but can be oxidized to Cr(VI) prior to determination, is the basis of the speciation analysis. The proposed speciation analysis was sensitive, yet simple, labor-effective, and cost-effective. It has been preliminarily applied for the speciation of Cr(VI) and Cr(III) in spiked river and tap water samples. It can also be used for other automatic liquid-liquid extraction-spectrophotometric determinations.

Determination of three estrogens and bisphenol A by functional ionic liquid dispersive liquid-phase microextraction coupled with ultra-high performance liquid chromatography and ultraviolet detection.

PubMed

Jiang, Yuehuang; Tang, Tingting; Cao, Zhen; Shi, Guoyue; Zhou, Tianshu

2015-06-01

A hydroxyl-functionalized ionic liquid, 1-hydroxyethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, was employed in an improved dispersive liquid-phase microextraction method coupled with ultra high performance liquid chromatography for the enrichment and determination of three estrogens and bisphenol A in environmental water samples. The introduced hydroxyl group acted as the H-bond acceptor that dispersed the ionic liquid effectively in the aqueous phase without dispersive solvent or external force. Fourier transform infrared spectroscopy indicated that the hydroxyl group of the cation of the ionic liquid enhanced the combination of extractant and analytes through the formation of hydrogen bonds. The improvement of the extraction efficiency compared with that with the use of alkyl ionic liquid was proved by a comparison study. The main parameters including volume of extractant, temperature, pH, and extraction time were investigated. The calibration curves were linear in the range of 5.0-1000 μg/L for estrone, estradiol, and bisphenol A, and 10.0-1000 μg/L for estriol. The detection limits were in the range of 1.7-3.4 μg/L. The extraction efficiency was evaluated by enrichment factor that were between 85 and 129. The proposed method was proved to be simple, low cost, and environmentally friendly for the determination of the four endocrine disruptors in environmental water samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sensitive determination of methadone in human serum and urine by dispersive liquid-liquid microextraction based on the solidification of a floating organic droplet followed by HPLC-UV.

PubMed

Taheri, Salman; Jalali, Fahimeh; Fattahi, Nazir; Jalili, Ronak; Bahrami, Gholamreza

2015-10-01

Dispersive liquid-liquid microextraction based on solidification of floating organic droplet was developed for the extraction of methadone and determination by high-performance liquid chromatography with UV detection. In this method, no microsyringe or fiber is required to support the organic microdrop due to the usage of an organic solvent with a low density and appropriate melting point. Furthermore, the extractant droplet can be collected easily by solidifying it at low temperature. 1-Undecanol and methanol were chosen as extraction and disperser solvents, respectively. Parameters that influence extraction efficiency, i.e. volumes of extracting and dispersing solvents, pH, and salt effect, were optimized by using response surface methodology. Under optimal conditions, enrichment factor for methadone was 134 and 160 in serum and urine samples, respectively. The limit of detection was 3.34 ng/mmL in serum and 1.67 ng/mL in urine samples. Compared with the traditional dispersive liquid-liquid microextraction, the proposed method obtained lower limit of detection. Moreover, the solidification of floating organic solvent facilitated the phase transfer. And most importantly, it avoided using high-density and toxic solvents of traditional dispersive liquid-liquid microextraction method. The proposed method was successfully applied to the determination of methadone in serum and urine samples of an addicted individual under methadone therapy. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

PubMed

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.

Dispersive liquid-liquid microextraction based on solidification of floating organic droplet followed by high-performance liquid chromatography with ultraviolet detection and liquid chromatography-tandem mass spectrometry for the determination of triclosan and 2,4-dichlorophenol in water samples.

PubMed

Zheng, Cao; Zhao, Jing; Bao, Peng; Gao, Jin; He, Jin

2011-06-24

A novel, simple and efficient dispersive liquid-liquid microextraction based on solidification of floating organic droplet (DLLME-SFO) technique coupled with high-performance liquid chromatography with ultraviolet detection (HPLC-UV) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the determination of triclosan and its degradation product 2,4-dichlorophenol in real water samples. The extraction solvent used in this work is of low density, low volatility, low toxicity and proper melting point around room temperature. The extractant droplets can be collected easily by solidifying it at a lower temperature. Parameters that affect the extraction efficiency, including type and volume of extraction solvent and dispersive solvent, salt effect, pH and extraction time, were investigated and optimized in a 5 mL sample system by HPLC-UV. Under the optimum conditions (extraction solvent: 12 μL of 1-dodecanol; dispersive solvent: 300 of μL acetonitrile; sample pH: 6.0; extraction time: 1 min), the limits of detection (LODs) of the pretreatment method combined with LC-MS/MS were in the range of 0.002-0.02 μg L(-1) which are lower than or comparable with other reported approaches applied to the determination of the same compounds. Wide linearities, good precisions and satisfactory relative recoveries were also obtained. The proposed technique was successfully applied to determine triclosan and 2,4-dichlorophenol in real water samples. Copyright © 2011 Elsevier B.V. All rights reserved.

Stereoselective quantitation of mecoprop and dichlorprop in natural waters by supramolecular solvent-based microextraction, chiral liquid chromatography and tandem mass spectrometry.

PubMed

Caballo, C; Sicilia, M D; Rubio, S

2013-01-25

Liquid chromatography (LC)/tandem mass spectrometry (MS/MS) after supramolecular solvent-based microextraction (SUSME) was firstly used in this work for the enantioselective determination of chiral pesticides in natural waters. The method developed for the quantitation of the R- and S-enantiomers of mecoprop (MCPP) and dichlorprop (DCPP) involved the extraction of the herbicides in a supramolecular solvent (SUPRAS) made up of reverse aggregates of dodecanoic acid (DoA), analyte re-extraction in acetate buffer (pH = 5.0), separation of the target enantiomers on a chiral column of permethylated α-cyclodextrin under isocratic conditions, and detection of the daughter ions (m/z = 140.9 and 160.6 for MCPP and DCPP, respectively) using a hybrid triple quadrupole mass spectrometer equipped with an electrospray source operating in the negative ion mode. Similar recoveries (ca. 75%) and actual concentration factors (ca. 94) were obtained for both phenoxypropanoic acids (PPAs). The quantitation limits were 1 ng L(-1) for R- and S-MCPP, and 4 ng L(-1) for R- and S-DCPP, and the precision, expressed as relative standard deviation (n = 6) was in the ranges 2.4-2.7% ([R-MCPP] = [S-MCPP] = 5 ng L(-1) and [R-DCPP] = [S-DCPP] = 15 ng L(-1)) and 1.6-1.8% (100 ng L(-1) of each enantiomer). The SUSME-LC-MS/MS method was successfully applied to the determination of the enantiomers of MCPP and DCPP in river and underground waters, fortified at concentrations between 15 and 180 ng L(-1) at variable enantiomeric ratios (ER = 1-9). Copyright © 2012 Elsevier B.V. All rights reserved.

Rapid analysis of aflatoxins B1, B2, and ochratoxin A in rice samples using dispersive liquid-liquid microextraction combined with HPLC.

PubMed

Lai, Xian-Wen; Sun, Dai-Li; Ruan, Chun-Qiang; Zhang, He; Liu, Cheng-Lan

2014-01-01

A novel, simple, and rapid method is presented for the analysis of aflatoxin B1, aflatoxin B2, and ochratoxin A in rice samples by dispersive liquid-liquid microextraction combined with LC and fluorescence detection. After extraction of the rice samples with a mixture of acetonitrile/water/acetic acid, mycotoxins were rapidly partitioned into a small volume of organic solvent (chloroform) by dispersive liquid-liquid microextraction. The three mycotoxins were simultaneously determined by LC with fluorescence detection after precolumn derivatization for aflatoxin B1 and B2. Parameters affecting both extraction and dispersive liquid-liquid microextraction procedures, including the extraction solvent, the type and volume of extractant, the volume of dispersive solvent, the addition of salt, the pH and the extraction time, were optimized. The optimized protocol provided an enrichment factor of approximately 1.25 and with detection of limits (0.06-0.5 μg/kg) below the maximum levels imposed by current regulations for aflatoxins and ochratoxin A. The mean recovery of three mycotoxins ranged from 82.9-112%, with a RSD less than 7.9% in all cases. The method was successfully applied to measure mycotoxins in commercial rice samples collected from local supermarkets in China. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of triazine herbicides in fresh vegetables by dynamic microwave-assisted extraction coupled with homogeneous ionic liquid microextraction high performance liquid chromatography.

PubMed

Wu, Lijie; Hu, Mingzhu; Li, Zhanchao; Song, Ying; Yu, Cui; Zhang, Yupu; Zhang, Hanqi; Yu, Aimin; Ma, Qiang; Wang, Ziming

2015-02-01

A novel extraction method, dynamic microwave-assisted extraction coupled with homogeneous ionic liquid microextraction, was developed for the determination of triazine herbicides, including desmetryn, terbumeton, propazine, terbuthylazine, dimethametryn, and dipropetryn in fresh vegetable samples by high performance liquid chromatography (HPLC). In the developed method, 120 μL of 1-butyl-3-methylimidazolium tetrafluoroborate ([C4MIM][BF4]) was added to 10 mL of aqueous solution containing 0.3 g of NaCl to obtained the extraction solvent. Six triazines could be extracted completely within 4 min by the present method. Then, [NH4][PF6] was added into the extract to form a water-insoluble ionic liquid [C4MIM][PF6] via a simple metathesis reaction, and the analytes were enriched into the ionic liquid phase. After centrifugation and dilution with acetonitrile, the resulting solution was analyzed directly by HPLC. The effects of some experimental parameters, including type and volume of ionic liquid, volume of extraction solvent, amount of ion-pairing agent [NH4][PF6], salt concentration, microwave power, and flow rate of extraction solvent on the extraction efficiency were investigated and optimized. Under the optimum experimental conditions, the linearity for determining the analytes was in the range of 2.50-250.00 μg kg(-1), with the correlation coefficients ranging from 0.9989 to 0.9999. When the present method was applied to the analysis of vegetable samples, satisfactory recoveries were obtained in the range of 76.8%-106.9%, and relative standard deviations were lower than 9.8%.

Waterflooding injectate design systems and methods

DOEpatents

Brady, Patrick V.; Krumhansl, James L.

2016-12-13

A method of recovering a liquid hydrocarbon using an injectate includes recovering the liquid hydrocarbon through primary extraction. Physico-chemical data representative of electrostatic interactions between the liquid hydrocarbon and the reservoir rock are measured. At least one additive of the injectate is selected based on the physico-chemical data. The method includes recovering the liquid hydrocarbon from the reservoir rock through secondary extraction using the injectate.

Preconcentration of aqueous dyes through phase-transfer liquid-phase microextraction with a room-temperature ionic liquid.

PubMed

Chen, Hsiu-Liang; Chang, Shuo-Kai; Lee, Chia-Ying; Chuang, Li-Lin; Wei, Guor-Tzo

2012-09-12

In this study, we employed the room-temperature ionic liquid [bmim][PF(6)] as both ion-pair agent and an extractant in the phase-transfer liquid-phase microextraction (PTLPME) of aqueous dyes. In the PTLPME method, a dye solution was added to the extraction solution, comprising a small amount of [bmim][PF(6)] in a relatively large amount of CH(2)Cl(2), which serves as the disperser solvent to an extraction solution. Following extraction, CH(2)Cl(2) was evaporated from the extractant, resulting in the extracted dyes being concentrated in a small volume of the ionic liquid phase to increase the enrichment factor. The enrichment factors of for the dye Methylene Blue, Neutral Red, and Methyl Red were approximately 500, 550 and 400, respectively; their detection limits were 0.014, 0.43, and 0.02 μg L(-1), respectively, with relative standard deviations of 4.72%, 4.20%, and 6.10%, respectively. Copyright © 2012 Elsevier B.V. All rights reserved.

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

NASA Technical Reports Server (NTRS)

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.

[Determination of capsaicinoids and eugenol in waste-edible-oil by liquid-liquid extraction and liquid chromatography-tandem mass spectrometry].

PubMed

Zhang, Zhong; Ren, Fei; Zhang, Pan

2012-11-01

A method was developed for the determination of capsaicinoids (capsaicin, dihydrocapsaicin and synthetic capsaicin) and eugenol in waste-edible-oil extracted by liquid-liquid extraction and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The capsaicinoids and eugenol in waste-edible-oil were extracted by methanol, and then separated by a SUPEL COSIL ABZ + Plus dC18 column (150 mm x4.6 mm, 5 microm). The analysis was performed by MS/MS with electrospray ionization in positive and negative ion modes with multiple reaction monitoring (MRM). The limits of detection for capsaicin, dihydrocapsaicin, synthetic capsaicin and eugenol were 0.02, 0.03, 0.03 and 0.6 microg/L, respectively. The good linear relationships were obtained in certain concentration ranges of capsaicinoids and eugenol. The relative standard deviations (RSDs, n=5) of same-worker and different-worker were less than 5%. The method is exclusive, sensitive and accurate, and can be used in waste-edible-oil determination.

Determination of rutin and quercetin in Chinese herbal medicine by ionic liquid-based pressurized liquid extraction-liquid chromatography-chemiluminescence detection.

PubMed

Wu, Hongwei; Chen, Meilan; Fan, Yunchang; Elsebaei, Fawzi; Zhu, Yan

2012-01-15

A novel ionic liquid-based pressurized liquid extraction (IL-PLE) procedure coupled with high performance liquid chromatography (HPLC) tandem chemiluminescence (CL) detection capable of quantifying trace amounts of rutin and quercetin in four Chinese medicine plants including Flos sophorae Immaturus, Crateagus pinnatifida Bunge, Hypericum japonicum Thunb and Folium Mori was described in this paper. To avoid environmental pollution and toxicity to the operators, ionic liquids (ILs), 1-alkyl-3-methylimidazolium chloride ([C(n)mim][Cl]) aqueous solutions were used in the PLE procedure as extractants replacing traditional organic solvents. In addition, chemiluminescence detection was utilized for its minimal interference from endogenous components of complex matrix. Parameters affecting extraction and analysis were carefully optimized. Compared with the conventional ultrasonic-assisted extraction (UAE) and heat-reflux extraction (HRE), the optimized method achieved the highest extraction efficiency in the shortest extraction time with the least solvent consumption. The applicability of the proposed method to real sample was confirmed. Under the optimized conditions, good reproducibility of extraction performance was obtained and good linearity was observed with correlation coefficients (r) between 0.9997 and 0.9999. The detection limits of rutin and quercetin (LOD, S/N=3) were 1.1×10(-2)mg/L and 3.8×10(-3)mg/L, respectively. The average recoveries of rutin and quercetin for real samples were 93.7-105% with relative standard deviation (RSD) lower than 5.7%. To the best of our knowledge, this paper is the first contribution to utilize a combination of IL-PLE with chemiluminescence detection. And the experimental results indicated that the proposed method shows a promising prospect in extraction and determination of rutin and quercetin in medicinal plants. Copyright © 2011 Elsevier B.V. All rights reserved.

Oxidative desulfurization of fuel oil by pyridinium-based ionic liquids.

PubMed

Zhao, Dishun; Wang, Yanan; Duan, Erhong

2009-10-28

In this work, an N-butyl-pyridinium-based ionic liquid [BPy]BF(4) was prepared. The effect of extraction desulfurization on model oil with thiophene and dibenzothiophene (DBT) was investigated. Ionic liquids and hydrogen peroxide (30%) were tested in extraction-oxidation desulfurization of model oil. The results show that the ionic liquid [BPy]BF(4) has a better desulfurization effect. The best technological conditions are: V(IL)/V(Oil) /V(H(2)O(2)) = 1:1:0.4, temperature 55 degrees C, the time 30 min. The ratio of desulfurization to thiophene and DBT reached 78.5% and 84.3% respectively, which is much higher than extraction desulfurization with simple ionic liquids. Under these conditions, the effect of desulfurization on gasoline was also investigated. The used ionic liquids can be recycled up to four times after regeneration.

Selective extraction and recovery of rare earth metals from phosphor powders in waste fluorescent lamps using an ionic liquid system.

PubMed

Yang, Fan; Kubota, Fukiko; Baba, Yuzo; Kamiya, Noriho; Goto, Masahiro

2013-06-15

The recycling of rare earth metals from phosphor powders in waste fluorescent lamps by solvent extraction using ionic liquids was studied. Acid leaching of rare earth metals from the waste phosphor powder was examined first. Yttrium (Y) and europium (Eu) dissolved readily in the acid solution; however, the leaching of other rare earth metals required substantial energy input. Ionization of target rare earth metals from the waste phosphor powders into the leach solution was critical for their successful recovery. As a high temperature was required for the complete leaching of all rare earth metals, ionic liquids, for which vapor pressure is negligible, were used as an alternative extracting phase to the conventional organic diluent. An extractant, N, N-dioctyldiglycol amic acid (DODGAA), which was recently developed, showed a high affinity for rare earth metal ions in liquid-liquid extraction although a conventional commercial phosphonic extractant did not. An effective recovery of the rare earth metals, Y, Eu, La and Ce, from the metal impurities, Fe, Al and Zn, was achieved from the acidic leach solution of phosphor powders using an ionic liquid containing DODGAA as novel extractant system. Copyright © 2013 Elsevier B.V. All rights reserved.

Magnetic graphene oxide modified by imidazole-based ionic liquids for the magnetic-based solid-phase extraction of polysaccharides from brown alga.

PubMed

Wang, Xiaoqin; Li, Guizhen; Row, Kyung Ho

2017-08-01

Magnetic graphene oxide was modified by four imidazole-based ionic liquids to synthesize materials for the extraction of polysaccharides by magnetic solid-phase extraction. Fucoidan and laminarin were chosen as the representative polysaccharides owing to their excellent pharmaceutical value and availability. Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, and thermogravimetric analysis were applied to characterize the synthesized materials. Single-factor experiments showed that the extraction efficiency of polysaccharides was affected by the amount of ionic liquids for modification, solid-liquid ratio of brown alga and ethanol, the stirring time of brown alga and ionic liquid-modified magnetic graphene oxide materials, and amount of 1-(3-aminopropyl)imidazole chloride modified magnetic graphene oxide materials added to the brown alga sample solution. The results indicated that 1-(3-aminopropyl)imidazole chloride modified magnetic graphene oxide possessed better extraction ability than graphene oxide, magnetic graphene oxide, and other three ionic-liquid-modified magnetic graphene oxide materials. The highest extraction recoveries of fucoidan and laminarin extracted by 1-(3-aminopropyl)imidazole chloride modified magnetic graphene oxide were 93.3 and 87.2%, respectively. In addition, solid materials could be separated and reused easily owing to their magnetic properties. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Enantioselective recognition at mesoporous chiral metal surfaces.

PubMed

Wattanakit, Chularat; Côme, Yémima Bon Saint; Lapeyre, Veronique; Bopp, Philippe A; Heim, Matthias; Yadnum, Sudarat; Nokbin, Somkiat; Warakulwit, Chompunuch; Limtrakul, Jumras; Kuhn, Alexander

2014-01-01

Chirality is widespread in natural systems, and artificial reproduction of chiral recognition is a major scientific challenge, especially owing to various potential applications ranging from catalysis to sensing and separation science. In this context, molecular imprinting is a well-known approach for generating materials with enantioselective properties, and it has been successfully employed using polymers. However, it is particularly difficult to synthesize chiral metal matrices by this method. Here we report the fabrication of a chirally imprinted mesoporous metal, obtained by the electrochemical reduction of platinum salts in the presence of a liquid crystal phase and chiral template molecules. The porous platinum retains a chiral character after removal of the template molecules. A matrix obtained in this way exhibits a large active surface area due to its mesoporosity, and also shows a significant discrimination between two enantiomers, when they are probed using such materials as electrodes.

Enantiomerization and stereoselectivity in bioaccumulation of furalaxyl in Tenebrio molitor larvae.

PubMed

Yin, Jing; Gao, Yongxin; Zhu, Feilong; Hao, Weiyu; Xu, Qi; Wang, Huili; Guo, Baoyuan

2017-11-01

Furalaxyl is a chiral pesticide and widely used in modern agriculture as racemate mixture. The enantiomerization and enantioselecive bioaccumulation by a single dose of furalaxyl to Tenebrio molitor larvae under laboratory conditions were studied using a high-performance liquid chromatography tandem mass spectroscopy method based on a ChiralPAK IC column. Our results showed that a significant enantiomerization (interconversion between R-enantiomer and S-enantiomer) was observed in Tenebrio molitor larvae under R- or S-furalaxyl exposure. Though the two furalaxyl enantiomers exhibited low-capacity of bioaccumulation in Tenebrio molitor larvae, bioaccumulation of rac-furalaxyl was enantioselective with a preferential accumulation of S-furalaxyl at 10mg/kg dosage exposure. In addition, enantiomerization and enantioselective degradation of the two enantiomers was not observed in wheat bran. These results showed that enantioselectivtiy of furalaxyl enantiomers was an important process combined with degradation, metabolism and enatiomerization in organisms. Copyright © 2017 Elsevier Inc. All rights reserved.

Ionic liquid-based dispersive liquid-liquid microextraction with back-extraction coupled with capillary electrophoresis to determine phenolic compounds.

PubMed

Zhou, Caihong; Tong, Shanshan; Chang, Yunxia; Jia, Qiong; Zhou, Weihong

2012-04-01

Ionic liquid (IL) based dispersive liquid-liquid microextraction (DLLME) with back-extraction coupled with capillary electrophoresis ultraviolet detection was developed to determine four phenolic compounds (bisphenol-A, β-naphthol, α-naphthol, 2, 4-dichlorophenol) in aqueous cosmetics. The developed method was used to preconcentrate and clean up the four phenolic compounds including two steps. The analytes were transferred into room temperature ionic liquid (1-octyl-3-methylimidazolium hexafluorophosphate, [C(8) MIM][PF(6) ]) rich-phase in the first step. In the second step, the analytes were back-extracted into the alkaline aqueous phase. The effects of extraction parameters, such as type and volume of extraction solvent, type and volume of disperser, extraction and centrifugal time, sample pH, salt addition, and concentration and volume of NaOH in back-extraction were investigated. Under the optimal experimental conditions, the preconcentration factors were 60.1 for bisphenol-A, 52.7 for β-naphthol, 49.2 for α-naphthol, and 18.0 for 2, 4-dichlorophenol. The limits of detection for bisphenol-A, β-naphthol, α-naphthol and 2, 4-dichlorophenol were 5, 5, 8, and 100 ng mL(-1), respectively. Four kinds of aqueous cosmetics including toner, soften lotion, make-up remover, and perfume were analyzed and yielded recoveries ranging from 81.6% to 119.4%. The main advantages of the proposed method are quick, easy, cheap, and effective. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

PubMed

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.

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.

PubMed

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.

Separations by supported liquid membrane cascades

DOEpatents

Danesi, P.R.

1983-09-01

The invention describes a new separation technique which leads to multi-stage operations by the use of a series (a cascade) of alternated carrier-containing supported-liquid cation exchanger extractant and a liquid anion exchanger extractant (or a neutral extractant) as carrier. The membranes are spaced between alternated aqueous electrolytic solutions of different composition which alternatively provide positively charged extractable species and negatively charged (or zero charged) extractable species, of the chemical species to be separated. The alternated aqueous electrolytic solutions in addition to providing the driving force to the process, simultaneously function as a stripping solution from one type of membrane and as an extraction-promoting solution for the other type of membrane. The aqueous electrolytic solution and the supported liquid membranes are arranged to provide a continuous process.

Simultaneous analysis of the enantiomers of verapamil and norverapamil in rat plasma by liquid chromatography-tandem mass spectrometry.

PubMed

Mateus, Fabiano Henrique; Lepera, José Salvador; Marques, Maria Paula; Boralli, Vanessa Bergamin; Lanchote, Vera Lucia

2007-12-21

An enantioselective micromethod for the simultaneous analysis of verapamil (VER) and norverapamil (NOR) in plasma was developed, validated and applied to the study of the kinetic disposition of VER and NOR after the administration of a single oral dose of racemic-VER to rats. VER, NOR and the internal standard (paroxetine) were extracted from only 100-microL plasma samples using n-hexane and the enantiomers were resolved on a Chiralpak AD column using n-hexane:isopropanol:ethanol:diethylamine (88:6:6:0.1) as the mobile phase. The analyses were performed in the selected reaction monitoring mode. Transitions 456>166 for VER enantiomers, 441>166 for NOR enantiomers and 330>193 for the internal standard were monitored and the method had a total chromatographic run time of 12 min. The method allows the determination of VER and NOR enantiomers at plasma levels as low as 1.0 ng/mL. Racemic VER hydrochloride (10mg/kg) was given to male Wistar rats by gavage and blood samples were collected from 0 to 6.0 h (n=6 at each time point). The concentration of (-)-(S)-VER was three folds higher than (+)-(R)-VER, with an AUC ratio (-)/(+) of 2.66. Oral clearance values were 12.17 and 28.77 L/h/kg for (-)-(S)-VER and (+)-(R)-VER, respectively. The pharmacokinetic parameters of NOR were not shown to be enantioselective.

Determination of triazine herbicides in juice samples by microwave-assisted ionic liquid/ionic liquid dispersive liquid-liquid microextraction coupled with high-performance liquid chromatography.

PubMed

Su, Rui; Li, Dan; Wu, Lijie; Han, Jing; Lian, Wenhui; Wang, Keren; Yang, Hongmei

2017-07-01

A novel microextraction method, termed microwave-assisted ionic liquid/ionic liquid dispersive liquid-liquid microextraction, has been developed for the rapid enrichment and analysis of triazine herbicides in fruit juice samples by high-performance liquid chromatography. Instead of using hazardous organic solvents, two kinds of ionic liquids, a hydrophobic ionic liquid (1-hexyl-3-methylimidazolium hexafluorophosphate) and a hydrophilic ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate), were used as the extraction solvent and dispersion agent, respectively, in this method. The extraction procedure was induced by the formation of cloudy solution, which was composed of fine drops of 1-hexyl-3-methylimidazolium hexafluorophosphate dispersed entirely into sample solution with the help of 1-butyl-3-methylimidazolium tetrafluoroborate. In addition, an ion-pairing agent (NH 4 PF 6 ) was introduced to improve recoveries of the ionic liquid phase. Several experimental parameters that might affect the extraction efficiency were investigated. Under the optimum experimental conditions, the linearity for determining the analytes was in the range of 5.00-250.00 μg/L, with the correlation coefficients of 0.9982-0.9997. The practical application of this effective and green method is demonstrated by the successful analysis of triazine herbicides in four juice samples, with satisfactory recoveries (76.7-105.7%) and relative standard deviations (lower than 6.6%). In general, this method is fast, effective, and robust to determine triazine herbicides in juice samples. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Task-specific ionic liquid-assisted extraction and separation of astaxanthin from shrimp waste.

PubMed

Bi, Wentao; Tian, Minglei; Zhou, Jun; Row, Kyung Ho

2010-08-15

Astaxanthin, as an outstanding antioxidant reagent, was successfully extracted from shrimp waste by the ionic liquids based ultrasonic-assisted extraction. Seven kinds of imidazolium ionic liquids with different cations and anions were investigated in this work and one task-specific ionic liquid in ethanol with 0.50molL(-1) was selected as the solvent. At the optimized ultrasonic extraction conditions, the extraction amount of astaxanthin increased 98% (92.7microg g(-1)) compared to the conventional method (46.7microg g(-1)). Furthermore, the extracted solution was isolated through the solid-phase extraction with a molecularly imprinted polymer sorbent. After loading the samples on molecularly imprinted polymer cartridge, the different washing and elution solvents, such as water, methanol, n-hexane, acetone and dichloromethane, were evaluated, and finally, astaxanthin was separated from the shrimp waste extract. Copyright 2010 Elsevier B.V. All rights reserved.

Advanced analytical techniques for the extraction and characterization of plant-derived essential oils by gas chromatography with mass spectrometry.

PubMed

Waseem, Rabia; Low, Kah Hin

2015-02-01

In recent years, essential oils have received a growing interest because of the positive health effects of their novel characteristics such as antibacterial, antifungal, and antioxidant activities. For the extraction of plant-derived essential oils, there is the need of advanced analytical techniques and innovative methodologies. An exhaustive study of hydrodistillation, supercritical fluid extraction, ultrasound- and microwave-assisted extraction, solid-phase microextraction, pressurized liquid extraction, pressurized hot water extraction, liquid-liquid extraction, liquid-phase microextraction, matrix solid-phase dispersion, and gas chromatography (one- and two-dimensional) hyphenated with mass spectrometry for the extraction through various plant species and analysis of essential oils has been provided in this review. Essential oils are composed of mainly terpenes and terpenoids with low-molecular-weight aromatic and aliphatic constituents that are particularly important for public health. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An Efficient Strategy Based on Liquid-Liquid Extraction with Three-Phase Solvent System and High Speed Counter-Current Chromatography for Rapid Enrichment and Separation of Epimers of Minor Bufadienolide from Toad Meat.

PubMed

Zou, Denglang; Zhu, Xuelin; Zhang, Fan; Du, Yurong; Ma, Jianbin; Jiang, Renwang

2018-01-31

This study presents an efficient strategy based on liquid-liquid extraction with three-phase solvent system and high speed counter-current chromatography for rapid enrichment and separation of epimers of minor bufadienolide from toad meat. The reflux extraction conditions were optimized by response surface methodology first, and a novel three-phase solvent system composed of n-hexane/methyl acetate/acetonitrile/water (3:6:5:5, v/v) was developed for liquid-liquid extraction of the crude extract. This integrative extraction process could enrich minor bufadienolide from complex matrix efficiently and minimize the loss of minor targets induced by repeated extraction with different kinds of organic solvents occurring in the classical liquid two-phase extraction. As a result, four epimers of minor bufadienolide were greatly enriched in the middle phase and total content of these epimers of minor bufadienolide was increased from 3.25% to 46.23%. Then, the enriched four epimers were separated by HSCCC with a two-phase solvent system composed of chloroform/methanol/water (4:2:2, v/v) successfully. Furthermore, we tested Na + ,K + -ATPase (NKA) inhibitory effect of the four epimers. 3β-Isomers of bufadienolide showed stronger (>8-fold) inhibitory activity than 3α-isomers. The characterization of minor bufadienolide in toad meat and their significant difference of inhibitory effect on NKA would promote the further quantitative analysis and safety evaluation of toad meat as a food source.

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

PubMed Central

2017-01-01

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. PMID:28151648

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

PubMed

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).

40 CFR 60.631 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... this subpart. Field gas means feedstock gas entering the natural gas processing plant. In light liquid... field gas before the extraction step in the process. Natural gas liquids means the hydrocarbons, such as... (gas plant) means any processing site engaged in the extraction of natural gas liquids from field gas...

40 CFR 60.631 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... this subpart. Field gas means feedstock gas entering the natural gas processing plant. In light liquid... field gas before the extraction step in the process. Natural gas liquids means the hydrocarbons, such as... (gas plant) means any processing site engaged in the extraction of natural gas liquids from field gas...

Application of liquid-liquid microextraction for the effective separation and simultaneous determination of 11 pharmaceuticals in wastewater samples using HPLC-MS/MS.

PubMed

Diuzheva, Alina; Balogh, József; Jekő, József; Cziáky, Zoltán

2018-05-17

A dispersive liquid-liquid microextraction method for the simultaneous determination of 11 pharmaceuticals has been developed. The method is based on a microextraction procedure applied to wastewater samples from different regions of Hungary followed by high performance liquid chromatography with mass spectrometry. The effect of the nature of the extractant, dispersive solvent, different additives and extraction time were examined on the extraction efficiently of the dispersive liquid-liquid microextraction method. Under optimal conditions, the linearity for determining the pharmaceuticals was in the range of 1-500 ng mL -1 , with the correlation coefficients ranging from 0.9922 to 0.9995. The limits of detection and limits of quantification were in the range 0.31-6.65 and 0.93-22.18 ng mL -1 , respectively. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Enantioselective Analytical- and Preparative-Scale Separation of Hexabromocyclododecane Stereoisomers Using Packed Column Supercritical Fluid Chromatography.

PubMed

Riddell, Nicole; Mullin, Lauren Gayle; van Bavel, Bert; Ericson Jogsten, Ingrid; McAlees, Alan; Brazeau, Allison; Synnott, Scott; Lough, Alan; McCrindle, Robert; Chittim, Brock

2016-11-10

Hexabromocyclododecane (HBCDD) is an additive brominated flame retardant which has been listed in Annex A of the Stockholm Convention for elimination of production and use. It has been reported to persist in the environment and has the potential for enantiomer-specific degradation, accumulation, or both, making enantioselective analyses increasingly important. The six main stereoisomers of technical HBCDD (i.e., the (+) and (-) enantiomers of α-, β-, and γ-HBCDD) were separated and isolated for the first time using enantioselective packed column supercritical fluid chromatography (pSFC) separation methods on a preparative scale. Characterization was completed using published chiral liquid chromatography (LC) methods and elution profiles, as well as X-ray crystallography, and the isolated fractions were definitively identified. Additionally, the resolution of the enantiomers, along with two minor components of the technical product (δ- and ε-HBCDD), was investigated on an analytical scale using both LC and pSFC separation techniques, and changes in elution order were highlighted. Baseline separation of all HBCDD enantiomers was achieved by pSFC on an analytical scale using a cellulose-based column. The described method emphasizes the potential associated with pSFC as a green method of isolating and analyzing environmental contaminants of concern.

Rapid pretreatment and determination of bisphenol A in water samples based on vortex-assisted liquid-liquid microextraction followed by high-performance liquid chromatography with fluorescence detection.

PubMed

Yang, Xiao; Diao, Chun-Peng; Sun, Ai-Ling; Liu, Ren-Min

2014-10-01

A method for the rapid pretreatment and determination of bisphenol A in water samples based on vortex-assisted liquid-liquid microextraction followed by high-performance liquid chromatography with fluorescence detection was proposed in this paper. A simple apparatus consisting of a test tube and a cut-glass dropper was designed and applied to collect the floating extraction drop in liquid-liquid microextraction when low-density organic solvent was used as the extraction solvent. Solidification and melting steps that were tedious but necessary once the low-density organic solvent used as extraction solvent could be avoided by using this apparatus. Bisphenol A was selected as model pollutant and vortex-assisted liquid-liquid microextraction was employed to investigate the usefulness of the apparatus. High-performance liquid chromatography with fluorescence detection was selected as the analytical tool for the detection of bisphenol A. The linear dynamic range was from 0.10 to 100 μg/L for bisphenol A, with good squared regression coefficient (r(2) = 0.9990). The relative standard deviation (n = 7) was 4.7% and the limit of detection was 0.02 μg/L. The proposed method had been applied to the determination of bisphenol A in natural water samples and was shown to be economical, fast, and convenient. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

PubMed

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 GmbH & Co. KGaA, Weinheim.

Ionic-liquid-based ultrasound/microwave-assisted extraction of 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one and 6-methoxy-benzoxazolin-2-one from maize (Zea mays L.) seedlings.

PubMed

Li, Chunying; Lu, Zhicheng; Zhao, Chunjian; Yang, Lei; Fu, Yujie; Shi, Kunming; He, Xin; Li, Zhao; Zu, Yuangang

2015-01-01

We evaluated an ionic-liquid-based ultrasound/microwave-assisted extraction method for the extraction of 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one and 6-methoxy-benzoxazolin-2-one from etiolated maize seedlings. We performed single-factor and central composite rotatable design experiments to optimize the most important parameters influencing this technique. The best results were obtained using 1.00 M 1-octyl-3-methylimidazolium bromide as the extraction solvent, a 50°C extraction temperature, a 20:1 liquid/solid ratio (mL/g), a 21 min treatment time, 590 W microwave power, and 50 W fixed ultrasonic power. We performed a comparison between ionic-liquid-based ultrasound/microwave-assisted extraction and conventional homogenized extraction. Extraction yields of 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one and 6-methoxy-benzoxazolin-2-one by the ionic-liquid-based ultrasound/microwave-assisted extraction method were 1.392 ± 0.051 and 0.205 ± 0.008 mg/g, respectively, which were correspondingly 1.46- and 1.32-fold higher than those obtained by conventional homogenized extraction. All the results show that the ionic-liquid-based ultrasound/microwave-assisted extraction method is therefore an efficient and credible method for the extraction of 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one and 6-methoxy-benzoxazolin-2-one from maize seedlings. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Application of ionic liquid in liquid phase microextraction technology.

PubMed

Han, Dandan; Tang, Baokun; Lee, Yu Ri; Row, Kyung Ho

2012-11-01

Ionic liquids (ILs) are novel nonmolecular solvents. Their unique properties, such as high thermal stability, tunable viscosity, negligible vapor pressure, nonflammability, and good solubility for inorganic and organic compounds, make them excellent candidates as extraction media for a range of microextraction techniques. Many physical properties of ILs can be varied, and the structural design can be tuned to impart the desired functionality and enhance the analyte extraction selectivity, efficiency, and sensitivity. This paper provides an overview of the applications of ILs in liquid phase microextraction technology, such as single-drop microextraction, hollow fiber based liquid phase microextraction, and dispersive liquid-liquid microextraction. The sensitivity, linear calibration range, and detection limits for a range of target analytes in the methods were analyzed to determine the advantages of ILs in liquid phase microextraction. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of chlorophenols in honey samples using in-situ ionic liquid-dispersive liquid-liquid microextraction as a pretreatment method followed by high-performance liquid chromatography.

PubMed

Fan, Chen; Li, Nai; Cao, Xueli

2015-05-01

In-situ ionic liquid-dispersive liquid-liquid microextraction (IL-DLLME) method was developed as a pretreatment method for the detection of six chlorophenols (CPs) in honey samples. The hydrophobic ionic liquid [C4MIM][NTf2], formed in-situ by the hydrophilic ionic liquid [C4MIM][BF4] and the ion exchange reagent LiNTf2 was used as the microextractant solvent of CPs from honey sample. Then the enriched analytes were back-extracted into 40 μL of 0.14 M NaOH solution and finally subjected to analysis by high-performance liquid chromatography. The method showed low limit of detection of CPs, 0.8-3.2 μg/L and high enrichment factor, 34-65 with the recoveries range from 91.60% to 114.33%. The method is simple, rapid, environmentally friendly and with high extraction efficiency. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Non-conventional solvents in liquid phase microextraction and aqueous biphasic systems.

PubMed

An, Jiwoo; Trujillo-Rodríguez, María J; Pino, Verónica; Anderson, Jared L

2017-06-02

The development of rapid, convenient, and high throughput sample preparation approaches such as liquid phase microextraction techniques have been continuously developed over the last decade. More recently, significant attention has been given to the replacement of conventional organic solvents used in liquid phase microextraction techniques in order to reduce toxic waste and to improve selectivity and/or extraction efficiency. With these objectives, non-conventional solvents have been explored in liquid phase microextraction and aqueous biphasic systems. The utilized non-conventional solvents include ionic liquids, magnetic ionic liquids, and deep eutectic solvents. They have been widely used as extraction solvents or additives in various liquid phase microextraction modes including dispersive liquid-liquid microextraction, single-drop microextraction, hollow fiber-liquid phase microextraction, as well as in aqueous biphasic systems. This review provides an overview into the use of non-conventional solvents in these microextraction techniques in the past 5 years (2012-2016). Analytical applications of the techniques are also discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

Sequential injection ionic liquid dispersive liquid-liquid microextraction for thallium preconcentration and determination with flame atomic absorption spectrometry.

PubMed

Anthemidis, Aristidis N; Ioannou, Kallirroy-Ioanna G

2012-08-01

A novel, automatic on-line sequential injection dispersive liquid-liquid microextraction (SI-DLLME) method, based on 1-hexyl-3-methylimidazolium hexafluorophosphate ([Hmim][PF(6)]) ionic liquid as an extractant solvent was developed and demonstrated for trace thallium determination by flame atomic absorption spectrometry. The ionic liquid was on-line fully dispersed into the aqueous solution in a continuous flow format while the TlBr(4)(-) complex was easily migrated into the fine droplets of the extractant due to the huge contact area of them with the aqueous phase. Furthermore, the extractant was simply retained onto the surface of polyurethane foam packed into a microcolumn. No specific conditions like low temperature are required for extractant isolation. All analytical parameters of the proposed method were investigated and optimized. For 15 mL of sample solution, an enhancement factor of 290, a detection limit of 0.86 μg L(-1) and a precision (RSD) of 2.7% at 20.0 μg L(-1) Tl(I) concentration level, was obtained. The developed method was evaluated by analyzing certified reference materials while good recoveries from environmental and biological samples proved that present method was competitive in practical applications.

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

EPA Pesticide Factsheets

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.

Composition of liquid rice hull smoke and anti-inflamatory effects in mice

USDA-ARS?s Scientific Manuscript database

Antioxidative, antiallergic, and antiinflammatory activities of a new liquid rice hull (husk) smoke extract prepared by pyrolysis of rice hulls followed by liquefaction of the resulting smoke were assessed in vitro and in vivo. At pH 5, the liquid smoke extract inhibited 1-diphenyl-2-picrylhydrazyl ...

Low Density Solvent-Based Dispersive Liquid-Liquid Microextraction for the Determination of Synthetic Antioxidants in Beverages by High-Performance Liquid Chromatography

PubMed Central

Çabuk, Hasan; Köktürk, Mustafa

2013-01-01

A simple and efficient method was established for the determination of synthetic antioxidants in beverages by using dispersive liquid-liquid microextraction combined with high-performance liquid chromatography with ultraviolet detection. Butylated hydroxy toluene, butylated hydroxy anisole, and tert-butylhydroquinone were the antioxidants evaluated. Experimental parameters including extraction solvent, dispersive solvent, pH of sample solution, salt concentration, and extraction time were optimized. Under optimal conditions, the extraction recoveries ranged from 53 to 96%. Good linearity was observed by the square of correlation coefficients ranging from 0.9975 to 0.9997. The relative standard deviations ranged from 1.0 to 5.2% for all of the analytes. Limits of detection ranged from 0.85 to 2.73 ng mL−1. The method was successfully applied for determination of synthetic antioxidants in undiluted beverage samples with satisfactory recoveries. PMID:23853535

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

PubMed

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.

Simultaneous enantioselective determination of triadimefon and its metabolite triadimenol in edible vegetable oil by gel permeation chromatography and ultraperformance convergence chromatography/tandem mass spectrometry.

PubMed

Yao, Zhoulin; Li, Xiaoge; Miao, Yelong; Lin, Mei; Xu, Mingfei; Wang, Qiang; Zhang, Hu

2015-11-01

A novel, sensitive, and efficient enantioselective method for the determination of triadimefon and its metabolite triadimenol in edible vegetable oil, was developed by gel permeation chromatography and ultraperformance convergence chromatography/tandem triple quadrupole mass spectrometry. After the vegetable oil samples were prepared using gel permeation chromatography, the eluent was collected, evaporated, and dried with nitrogen gas. The residue was redissolved by adding methanol up to a final volume of 1 mL. The analytes of six enantiomers were analyzed on Chiralpak IA-3 column (150 × 4.6 mm) using compressed liquid CO2-mixed 14 % co-solvents, comprising methanol/acetonitrile/isopropanol = 20/20/60 (v/v/v) in the mobile phase at 30 °C, and the total separation time was less than 4 min at a flow rate of 2 mL/min. Quantification was achieved using matrix-matched standard calibration curves. The overall mean recoveries for six enantiomers from vegetable oil were 90.1-97.3 %, with relative standard deviations of 0.8-5.4 % intra-day and 2.3-5.0 % inter-day at 0.5, 5, and 50 μg/kg levels. The limits of quantification were 0.5 μg/kg for all enantiomers based on five replicate extractions at the lowest fortified level in vegetable oil. Moreover, the absolute configuration of six enantiomers had been determined based on comparisons of the vibrational circular dichroism experimental spectra with the theoretical curve obtained by density functional theory calculations. Application of the proposed method to the 40 authentic vegetable oil samples from local markets suggests its potential use in enantioselective determination of triadimefon and triadimenol enantiomers. Graphical Abstract Chemical structures and UPC(2)-MS/MS separation chromatograms of triadimefon and triadimenol.

A rapid and simple pretreatment method for benzoylurea insecticides in honey samples using in-syringe dispersive liquid-liquid microextraction based on the direct solidification of ionic liquids.

PubMed

Wang, Huazi; Hu, Lu; Li, Wanzhen; Lu, Runhua; Zhang, Sanbing; Zhou, Wenfeng; Gao, Haixiang

2016-11-04

A pretreatment method using in-syringe dispersive liquid-liquid microextraction based on the direct solidification of ionic liquids before high performance liquid chromatography analysis was developed for the determination of benzoylurea insecticides (BUs) in honey samples. The hydrophobic ionic liquid [N 4444 ][PF 6 ], formed in situ by the hydrophilic ionic liquid [N 4444 ]Cl and the ion exchange reagent KPF 6 , was used to extract the target analytes. The entire extraction procedure was performed in a syringe. The extractant was solidified at room temperature and collected using a nylon membrane filter. This technique did not require a dispersive solvent, vortex mixer, ultrasound bath, or centrifugation. The parameters affecting the extraction efficiency were investigated through an experimental design. Under the optimal conditions, the limits of detection for the four BUs varied from 0.21 to 0.42μgL -1 in solution (2.1-4.2μgkg -1 in honey). Good linearities were obtained in the range of 2-300μgL -1 , with coefficients of determination greater than 0.999. The recoveries of the four BUs ranged from 80.94% to 84.59%. The intra-day (n=3) and inter-day (n=3) relative standard deviations were less than 5.08%. Finally, the proposed method was applied to the determination of BUs in commercial honey samples with satisfactory results. Copyright © 2016 Elsevier B.V. All rights reserved.

Aqueous two-phase based on ionic liquid liquid-liquid microextraction for simultaneous determination of five synthetic food colourants in different food samples by high-performance liquid chromatography.

PubMed

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

2015-05-01

A rapid and effective method of aqueous two-phase systems based on ionic liquid microextraction for the simultaneous determination of five synthetic food colourants (tartrazine, sunset yellow, amaranth, ponceau 4R and brilliant blue) in food samples was established. High-performance liquid chromatography coupled with an ultraviolet detector of variable wavelength was used for the determinations. 1-alkyl-3-methylimidazolium bromide was selected as the extraction reagent. The extraction efficiency of the five colourants in the proposed system is influenced by the types of salts, concentrations of salt and [CnMIM]Br, as well as the extracting time. Under the optimal conditions, the extraction efficiencies for these five colourants were above 95%. The phase behaviours of aqueous two-phase system and extraction mechanism were investigated by UV-vis spectroscopy. This method was applied to the analysis of the five colourants in real food samples with the detection limit of 0.051-0.074 ng/mL. Good spiked recoveries from 93.2% to 98.9% were obtained. Copyright © 2014 Elsevier Ltd. All rights reserved.

Feasibility of Surfactant-Free Supported Emulsion Liquid Membrane Extraction

NASA Technical Reports Server (NTRS)

Hu, Shih-Yao B.; Li, Jin; Wiencek, John M.

2001-01-01

Supported emulsion liquid membrane (SELM) is an effective means to conduct liquid-liquid extraction. SELM extraction is particularly attractive for separation tasks in the microgravity environment where density difference between the solvent and the internal phase of the emulsion is inconsequential and a stable dispersion can be maintained without surfactant. In this research, dispersed two-phase flow in SELM extraction is modeled using the Lagrangian method. The results show that SELM extraction process in the microgravity environment can be simulated on earth by matching the density of the solvent and the stripping phase. Feasibility of surfactant-free SELM (SFSELM) extraction is assessed by studying the coalescence behavior of the internal phase in the absence of the surfactant. Although the contacting area between the solvent and the internal phase in SFSELM extraction is significantly less than the area provided by regular emulsion due to drop coalescence, it is comparable to the area provided by a typical hollow-fiber membrane. Thus, the stripping process is highly unlikely to become the rate-limiting step in SFSELM extraction. SFSELM remains an effective way to achieve simultaneous extraction and stripping and is able to eliminate the equilibrium limitation in the typical solvent extraction processes. The SFSELM design is similar to the supported liquid membrane design in some aspects.

Indirect enantioseparation of fluoxetine in mouse serum by derivatization with 1R-(-)-menthyl chloroformate followed by ultra high performance liquid chromatography and quadrupole time-of-flight mass spectrometry.

PubMed

Zhao, Jing; Jin, Yan; Shin, Yujin; Jeong, Kyung Min; Lee, Jeongmi

2016-03-01

Here we describe a simple and sensitive analytical method for the enantioselective quantification of fluoxetine in mouse serum using ultra high performance liquid chromatography with quadrupole time-of-flight mass spectrometry. The sample preparation method included a simple deproteinization with acetonitrile in 50 μL of serum, followed by derivatization of the extracts in 50 μL of 2 mM 1R-(-)-menthyl chloroformate at 45ºC for 55 min. These conditions were statistically optimized through response surface methodology using a central composite design. Under the optimized conditions, neither racemization nor kinetic resolution occurred. The derivatized diastereomers were readily resolved on a conventional sub-2 μm C18 column under a simple gradient elution of aqueous methanol containing 0.1% formic acid. The established method was validated and found to be linear, precise, and accurate over the concentration range of 5.0-1000.0 ng/mL for both R and S enantiomers (r(2) > 0.993). Stability tests of the prepared samples at three different concentration levels showed that the R- and S-fluoxetine derivatives were relatively stable for 48 h. No significant matrix effects were observed. Last, the developed method was successfully used for enantiomeric analysis of real serum samples collected at a number of time points from mice administered with racemic fluoxetine. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

"Bligh and Dyer" and Folch Methods for Solid-Liquid-Liquid Extraction of Lipids from Microorganisms. Comprehension of Solvatation Mechanisms and towards Substitution with Alternative Solvents.

PubMed

Breil, Cassandra; Abert Vian, Maryline; Zemb, Thomas; Kunz, Werner; Chemat, Farid

2017-03-27

Bligh and Dyer (B & D) or Folch procedures for the extraction and separation of lipids from microorganisms and biological tissues using chloroform/methanol/water have been used tens of thousands of times and are "gold standards" for the analysis of extracted lipids. Based on the Conductor-like Screening MOdel for realistic Solvatation (COSMO-RS), we select ethanol and ethyl acetate as being potentially suitable for the substitution of methanol and chloroform. We confirm this by performing solid-liquid extraction of yeast ( Yarrowia lipolytica IFP29 ) and subsequent liquid-liquid partition-the two steps of routine extraction. For this purpose, we consider similar points in the ternary phase diagrams of water/methanol/chloroform and water/ethanol/ethyl acetate, both in the monophasic mixtures and in the liquid-liquid miscibility gap. Based on high performance thin-layer chromatography (HPTLC) to obtain the distribution of lipids classes, and gas chromatography coupled with a flame ionisation detector (GC/FID) to obtain fatty acid profiles, this greener solvents pair is found to be almost as effective as the classic methanol-chloroform couple in terms of efficiency and selectivity of lipids and non-lipid material. Moreover, using these bio-sourced solvents as an alternative system is shown to be as effective as the classical system in terms of the yield of lipids extracted from microorganism tissues, independently of their apparent hydrophilicity.

Ionic liquid-anionic surfactant based aqueous two-phase extraction for determination of antibiotics in honey by high-performance liquid chromatography.

PubMed

Yang, Xiao; Zhang, Shaohua; Yu, Wei; Liu, Zhongling; Lei, Lei; Li, Na; Zhang, Hanqi; Yu, Yong

2014-06-01

An ionic liquid-anionic surfactant based aqueous two-phase extraction was developed and applied for the extraction of tetracycline, oxytetracycline and chloramphenicol in honey. The honey sample was mixed with Na2EDTA aqueous solution. The sodium dodecyl sulfate, ionic liquid 1-octyl-3-methylimidazolium bromide and sodium chloride were added in the mixture. After the resulting mixture was ultrasonically shaken and centrifuged, the aqueous two phase system was formed and analytes were extracted into the upper phase. The parameters affecting the extraction efficiency, such as the volume of ionic liquid, the category and amount of salts, sample pH value, extraction time and temperature were investigated. The limits of detection of tetracycline, oxytetracycline and chloramphenicol were 5.8, 8.2 and 4.2 μg kg(-1), respectively. When the present method was applied to the analysis of real honey samples, the recoveries of analytes ranged from 85.5 to 110.9% and relative standard deviations were lower than 6.9%. Copyright © 2014 Elsevier B.V. All rights reserved.

A validated solid-liquid extraction method for the HPLC determination of polyphenols in apple tissues Comparison with pressurised liquid extraction.

PubMed

Alonso-Salces, Rosa M; Barranco, Alejandro; Corta, Edurne; Berrueta, Luis A; Gallo, Blanca; Vicente, Francisca

2005-02-15

A solid-liquid extraction procedure followed by reversed-phase high-performance liquid chromatography (RP-HPLC) coupled with a photodiode array detector (DAD) for the determination of polyphenols in freeze-dried apple peel and pulp is reported. The extraction step consists in sonicating 0.5g of freeze-dried apple tissue with 30mL of methanol-water-acetic acid (30:69:1, v/v/v) containing 2g of ascorbic acid/L, for 10min in an ultrasonic bath. The whole method was validated, concluding that it is a robust method that presents high extraction efficiencies (peel: >91%, pulp: >95%) and appropriate precisions (within day: R.S.D. (n = 5) <5%, and between days: R.S.D. (n = 5) <7%) at the different concentration levels of polyphenols that can be found in apple samples. The method was compared with one previously published, consisting in a pressurized liquid extraction (PLE) followed by RP-HPLC-DAD determination. The advantages and disadvantages of both methods are discussed.

Characterization of rhamnolipids by liquid chromatography/mass spectrometry after solid-phase extraction.

PubMed

Behrens, Beate; Engelen, Jeannine; Tiso, Till; Blank, Lars Mathias; Hayen, Heiko

2016-04-01

Rhamnolipids are surface-active agents with a broad application potential that are produced in complex mixtures by bacteria of the genus Pseudomonas. Analysis from fermentation broth is often characterized by laborious sample preparation and requires hyphenated analytical techniques like liquid chromatography coupled to mass spectrometry (LC-MS) to obtain detailed information about sample composition. In this study, an analytical procedure based on chromatographic method development and characterization of rhamnolipid sample material by LC-MS as well as a comparison of two sample preparation methods, i.e., liquid-liquid extraction and solid-phase extraction, is presented. Efficient separation was achieved under reversed-phase conditions using a mixed propylphenyl and octadecylsilyl-modified silica gel stationary phase. LC-MS/MS analysis of a supernatant from Pseudomonas putida strain KT2440 pVLT33_rhlABC grown on glucose as sole carbon source and purified by solid-phase extraction revealed a total of 20 congeners of di-rhamnolipids, mono-rhamnolipids, and their biosynthetic precursors 3-(3-hydroxyalkanoyloxy)alkanoic acids (HAAs) with different carbon chain lengths from C8 to C14, including three rhamnolipids with uncommon C9 and C11 fatty acid residues. LC-MS and the orcinol assay were used to evaluate the developed solid-phase extraction method in comparison with the established liquid-liquid extraction. Solid-phase extraction exhibited higher yields and reproducibility as well as lower experimental effort.

Assessment of dispersive liquid-liquid microextraction conditions for gas chromatography time-of-flight mass spectrometry identification of organic compounds in honey.

PubMed

Moniruzzaman, M; Rodríguez, I; Rodríguez-Cabo, T; Cela, R; Sulaiman, S A; Gan, S H

2014-11-14

The suitability of the dispersive liquid-liquid microextraction (DLLME) technique for gas chromatography (GC) characterization of minor organic compounds in honey samples is evaluated. Under optimized conditions, samples were pre-treated by liquid-liquid extraction with acetonitrile followed by DLLME using carbon tetrachloride (CCl4, 0.075 mL) as extractant. The yielded settled phase was analyzed by GC using high resolution time-of-flight (TOF) mass spectrometry (MS). The whole sample preparation process is completed in approximately 10 min, with a total consumption of organic solvents below 4 mL, relative standard deviations lower than 12% and with more than 70 organic compounds, displaying linear retention index in the range from 990 to 2900, identified in the obtained extracts. In comparison with HS SPME extraction, higher peak intensities were attained for most volatile and semi-volatile compounds amenable to both extraction techniques. Furthermore, other species such as highly polar and water soluble benzene acids, long chain fatty acids, esters and flavonoids, which are difficult to concentrate by HS SPME, could be identified in DLLME extracts. Some of the compounds identified in DLLME extracts have been proposed as useful for samples classification and/or they are recognized as markers of honeys from certain geographic areas. Copyright © 2014 Elsevier B.V. All rights reserved.

Application of Ionic Liquids in the Microwave-Assisted Extraction of Proanthocyanidins from Larix gmelini Bark

PubMed Central

Yang, Lei; Sun, Xiaowei; Yang, Fengjian; Zhao, Chunjian; Zhang, Lin; Zu, Yuangang

2012-01-01

Ionic liquid based, microwave-assisted extraction (ILMAE) was successfully applied to the extraction of proanthocyanidins from Larix gmelini bark. In this work, in order to evaluate the performance of ionic liquids in the microwave-assisted extraction process, a series of 1-alkyl-3-methylimidazolium ionic liquids with different cations and anions were evaluated for extraction yield, and 1-butyl-3-methylimidazolium bromide was selected as the optimal solvent. In addition, the ILMAE procedure for the proanthocyanidins was optimized and compared with other conventional extraction techniques. Under the optimized conditions, satisfactory extraction yield of the proanthocyanidins was obtained. Relative to other methods, the proposed approach provided higher extraction yield and lower energy consumption. The Larix gmelini bark samples before and after extraction were analyzed by Thermal gravimetric analysis, Fourier-transform infrared spectroscopy and characterized by scanning electron microscopy. The results showed that the ILMAE method is a simple and efficient technique for sample preparation. PMID:22606036

Hollow fiber supported ionic liquid membrane microextraction for determination of sulfonamides in environmental water samples by high-performance liquid chromatography.

PubMed

Tao, Yong; Liu, Jing-Fu; Hu, Xia-Lin; Li, Hong-Cheng; Wang, Thanh; Jiang, Gui-Bin

2009-08-28

By using ionic liquid as membrane liquid and tri-n-octylphosphine oxide (TOPO) as additive, hollow fiber supported liquid phase microextraction (HF-LPME) was developed for the determination of five sulfonamides in environmental water samples by high-performance liquid chromatography with ultraviolet detection The extraction solvent and the parameters affecting the extraction enrichment factor such as the type and amount of carrier, pH and volume ratio of donor phase and acceptor phase, extraction time, salt-out effect and matrix effect were optimized. Under the optimal extraction conditions (organic liquid membrane phase: [C(8)MIM][PF(6)] with 14% TOPO (w/v); donor phase: 4mL, pH 4.5 KH(2)PO(4) with 2M Na(2)SO(4); acceptor phase: 25microL, pH 13 NaOH; extraction time: 8 h), low detection limits (0.1-0.4microg/L, RSDor=0.999) were obtained for all the analytes. The presence of humic acid (0-25mg/L dissolved organic carbon) and bovine serum albumin (0-100microg/mL) had no significant effect on the extraction efficiency. Good spike recoveries over the range of 82.2-103.2% were obtained when applying the proposed method on five real environmental water samples. These results indicated that this present method was very sensitive and reliable with good repeatabilities and excellent clean-up in water samples. The proposed method confirmed hollow fiber supported ionic liquid membrane based LPME to be robust to monitoring trace levels of sulfadiazine, sulfamerazine, sulfamethazine, sulfadimethoxine and sulfamethoxazole in aqueous samples.

Laboratory studies on the removal of radon-born lead from KamLAND's organic liquid scintillator

NASA Astrophysics Data System (ADS)

Keefer, G.; Grant, C.; Piepke, A.; Ebihara, T.; Ikeda, H.; Kishimoto, Y.; Kibe, Y.; Koseki, Y.; Ogawa, M.; Shirai, J.; Takeuchi, S.; Mauger, C.; Zhang, C.; Schweitzer, G.; Berger, B. E.; Dazeley, S.; Decowski, M. P.; Detwiler, J. A.; Djurcic, Z.; Dwyer, D. A.; Efremenko, Y.; Enomoto, S.; Freedman, S. J.; Fujikawa, B. K.; Furuno, K.; Gando, A.; Gando, Y.; Gratta, G.; Hatakeyama, S.; Heeger, K. M.; Hsu, L.; Ichimura, K.; Inoue, K.; Iwamoto, T.; Kamyshkov, Y.; Karwowski, H. J.; Koga, M.; Kozlov, A.; Lane, C. E.; Learned, J. G.; Maricic, J.; Markoff, D. M.; Matsuno, S.; McKee, D.; McKeown, R. D.; Miletic, T.; Mitsui, T.; Motoki, M.; Nakajima, Kyo; Nakajima, Kyohei; Nakamura, K.; O`Donnell, T.; Ogawa, H.; Piquemal, F.; Ricol, J.-S.; Shimizu, I.; Suekane, F.; Suzuki, A.; Svoboda, R.; Tajima, O.; Takemoto, Y.; Tamae, K.; Tolich, K.; Tornow, W.; Watanabe, Hideki; Watanabe, Hiroko; Winslow, L. A.; Yoshida, S.

2015-01-01

The removal of radioactivity from liquid scintillator has been studied in preparation of a low background phase of KamLAND. This paper describes the methods and techniques developed to measure and efficiently extract radon decay products from liquid scintillator. We report the radio-isotope reduction factors obtained when applying various extraction methods. During this study, distillation was identified as the most efficient method for removing radon-born lead from liquid scintillator.

Laboratory studies on the removal of radon-born lead from KamLAND׳s organic liquid scintillator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keefer, G.; Grant, C.; Piepke, A.

We studied the removal of radioactivity from liquid scintillator in preparation of a low background phase of KamLAND. We describe the methods and techniques developed to measure and efficiently extract radon decay products from liquid scintillator. Lastly, we report the radio-isotope reduction factors obtained when applying various extraction methods. During this study, distillation was identified as the most efficient method for removing radon daughters from liquid scintillator.

Laboratory studies on the removal of radon-born lead from KamLAND׳s organic liquid scintillator

DOE PAGES

Keefer, G.; Grant, C.; Piepke, A.; ...

2014-09-28

We studied the removal of radioactivity from liquid scintillator in preparation of a low background phase of KamLAND. We describe the methods and techniques developed to measure and efficiently extract radon decay products from liquid scintillator. Lastly, we report the radio-isotope reduction factors obtained when applying various extraction methods. During this study, distillation was identified as the most efficient method for removing radon daughters from liquid scintillator.

Salting-out assisted liquid-liquid extraction coupled to ultra-high performance liquid chromatography-tandem mass spectrometry for the determination of tetracycline residues in infant foods.

PubMed

Moreno-González, David; García-Campaña, Ana M

2017-04-15

The use of salting-out assisted liquid-liquid extraction (SALLE) combined with ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) has been evaluated for the determination of tetracyclines in infant foods based on meat and vegetables or in milk. To obtain satisfactory extraction efficiencies for the studied analytes, several parameters affecting the SALLE procedure were optimized. Analytical performances of the method were satisfactory, obtaining limits of quantification lower than 0.48μgkg -1 in all cases. The precision, expressed as relative standard deviation (%, RSD) was below 11.3%. The extraction efficiency for fortified samples ranged from 89.2 to 96.8%, with RSDs lower than 7.3%. Matrix effect was evaluated for all samples studied, being lower than |21|% in all cases. In relation to the low solvent consumption, the proposed methodology could be considered rapid, cheap and environmentally friendly. Its applicability has been successfully tested in a wide range of infant foods. Copyright © 2016 Elsevier Ltd. All rights reserved.

Recovery of zinc and manganese from spent alkaline batteries by liquid-liquid extraction with Cyanex 272

NASA Astrophysics Data System (ADS)

Salgado, Aline L.; Veloso, Aline M. O.; Pereira, Daniel D.; Gontijo, Glayson S.; Salum, Adriane; Mansur, Marcelo B.

A hydrometallurgical route based on the liquid-liquid extraction technique using Cyanex 272 as extractant is investigated for the selective separation of metal values, in particular, zinc and manganese from spent alkaline batteries. The recycling route consists of following steps: (1) cryogenic dismantling of the spent batteries, (2) pre-treatment of the internal material consisting of drying, grinding and screening steps in order to produce a dry homogeneous powder, (3) leaching of the powder with sulphuric acid and (4) metal separation by liquid-liquid extraction. Bench scale experiments have shown that zinc and manganese are easily separated (ΔpH 1/2≈2.0) using 20% (v/v) Cyanex 272 dissolved in Escaid 110 at 50 °C. Therefore, the proposed route can treat residues from both zinc-carbon and alkaline batteries because metal composition of these batteries is quite similar. The metal content of other batteries such as Ni-Cd and nickel-metal hydride (NiMH) has been also determined in order to include them in future investigations.

Extraction and Esterification of Low-Titer Short-Chain Volatile Fatty Acids from Anaerobic Fermentation with Ionic Liquids.

PubMed

Andersen, Stephen J; Berton, Jan K E T; Naert, Pieter; Gildemyn, Sylvia; Rabaey, Korneel; Stevens, Christian V

2016-08-23

Ionic liquids can both act as a solvent and mediate esterification to valorize low-titer volatile fatty acids and generate organic solvents from renewable carbon sources including biowaste and CO2 . In this study, four phosphonium ionic liquids were tested for single-stage extraction of acetic acid from a dilute stream and esterification to ethyl acetate with added ethanol and heat. The esterification proceeded with a maximum conversion of 85.9±1.3 % after 30 min at 75 °C at a 1:1 stoichiometric ratio of reactants. Extraction and esterification can be tailored using mixed-anion ionic liquids; this is demonstrated herein using a common trihexyl(tetradecyl)phosphonium cation and a mixed chloride and bis(trifluoromethylsulfonyl)imide anion ionic liquid. As a further proof-of-concept, ethyl acetate was generated from an ionic liquid-driven esterification of an acetic acid extractant generated using CO2 as the only carbon source by microbial electrosynthesis. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sensitive quantitation of polyamines in plant foods by ultrasound-assisted benzoylation and dispersive liquid-liquid microextraction with the aid of experimental designs.

PubMed

Pinto, Edgar; Melo, Armindo; Ferreira, Isabel M P L V O

2014-05-14

A new method involving ultrasound-assisted benzoylation and dispersive liquid-liquid microextraction was optimized with the aid of chemometrics for the extraction, cleanup, and determination of polyamines in plant foods. Putrescine, cadaverine, spermidine, and spermine were derivatized with 3,5-dinitrobenzoyl chloride and extracted by dispersive liquid-liquid microextraction using acetonitrile and carbon tetrachloride as dispersive and extraction solvents, respectively. Two-level full factorial design and central composite design were applied to select the most appropriate derivatization and extraction conditions. The developed method was linear in the 0.5-10.0 mg/L range, with a R(2) ≥ 0.9989. Intra- and interday precisions ranged from 0.8 to 6.9% and from 3.0 to 10.3%, respectively, and the limit of detection ranged between 0.018 and 0.042 μg/g of fresh weight. This method was applied to the analyses of six different types of plant foods, presenting recoveries between 81.7 and 114.2%. The method is inexpensive, versatile, simple, and sensitive.

Centrifugal contactor with liquid mixing and flow control vanes and method of mixing liquids of different phases

DOEpatents

Jubin, Robert T.; Randolph, John D.

1991-01-01

The invention is directed to a centrifugal contactor for solvent extraction systems. The centrifugal contactor is provided with an annular vertically oriented mixing chamber between the rotor housing and the rotor for mixing process liquids such as the aqueous and organic phases of the solvent extraction process used for nuclear fuel reprocessing. A set of stationary helically disposed vanes carried by the housing is in the lower region of the mixing chamber at a location below the process-liquid inlets for the purpose of urging the liquids in an upward direction toward the inlets and enhancing the mixing of the liquids and mass transfer between the liquids. The upper region of the mixing vessel above the inlets for the process liquids is also provided with a set helically disposed vanes carried by the housing for urging the process liquids in a downward direction when the liquid flow rates through the inlets are relatively high and the liquids contact the vane set in the upper region. The use of these opposing vane sets in the mixing zone maintains the liquid in the mixing zone at suitable levels.

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

PubMed

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.

Application of liquid-liquid-liquid microextraction and high-performance liquid chromatography for the determination of alkylphenols and bisphenol-A in water.

PubMed

Lin, Che-Yi; Fuh, Ming-Ren; Huang, Shang-Da

2011-02-01

A method termed liquid-liquid-liquid microextraction (LLLME) was utilized to extract 4-t-butylphenol, 4-t-octylphenol, 4-n-nonylphenol, and bisphenol-A from water. The extracted target analytes were separated and quantified by high-performance liquid chromatography using a fluorescence detector. In LLLME, the donor phase (i.e. water sample) was made weakly acidic by adding monobasic potassium phosphate (KH(2) PO(4)); the organic phase adopted was 4-chlorotoluene; the acceptor phase (i.e. enriched extract) was 0.2 M tetraethylammonium hydroxide dissolved in ethylene glycol. This study solves a problem associated with the surface activity of long-chain alkylphenolate ions, permitting LLLME to extract long-chain alkylphenols. Experimental conditions such as acceptor phase composition, organic phase identity, acceptor phase volume, sample agitation, extraction time, and salt addition were optimized. The relative standard deviation (RSD, 2.0-5.8%), coefficient of determination (r(2) 0.9977-0.9999), and detection limit (0.017-0.0048 ng/mL) of the proposed method were achieved under the selected optimized conditions. The method was successfully applied to analyses of lake and tap water samples, and the relative recoveries of target analytes from the spiked lake and tap water samples were 92.8-106.3 and 93.6-105.6%, respectively. The results obtained with the proposed method confirm this microextraction technique to be reliable for the monitoring of alkylphenols and bisphenol-A in water samples. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Application of solid/liquid extraction for the gravimetric determination of lipids in royal jelly.

PubMed

Antinelli, Jean-François; Davico, Renée; Rognone, Catherine; Faucon, Jean-Paul; Lizzani-Cuvelier, Louisette

2002-04-10

Gravimetric lipid determination is a major parameter for the characterization and the authentication of royal jelly quality. A solid/liquid extraction was compared to the reference method, which is based on liquid/liquid extraction. The amount of royal jelly and the time of the extraction were optimized in comparison to the reference method. Boiling/rinsing ratio and spread of royal jelly onto the extraction thimble were identified as critical parameters, resulting in good accuracy and precision for the alternative method. Comparison of reproducibility and repeatability of both methods associated with gas chromatographic analysis of the composition of the extracted lipids showed no differences between the two methods. As the intra-laboratory validation tests were comparable to the reference method, while offering rapidity and a decrease in amount of solvent used, it was concluded that the proposed method should be used with no modification of quality criteria and norms established for royal jelly characterization.

Separation of m-cresol from neutral oils with liquid-liquid extraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Venter, D.L.; Nieuwoudt

Coal pyrolysis liquors are a major source of valuable phenolic compounds. In this study, the separation of m-cresol from neutral oils by means of liquid-liquid extraction is investigated. Liquid-liquid equilibria for the systems m-cresol + o-toluonitrile + hexane + water + tetraethylene glycol + undecane + dodecane and m-cresol + o-toluonitrile + hexane + water + tetraethylene glycol have bee determined at 313.15 K in order to evaluate the suitability of tetraethylene glycol as a high-boiling solvent for the separation of m-cresol from neutral oils. The effect of parameters such as solvent ratios on the desired separation were investigated. Thesemore » are illustrated on the basis of separation factors, percentage of feed o-toluonitrile remaining in the solvent phase, and percentage recovery of m-cresol. From the experimental results it was concluded that tetraethylene glycol is suitable for the proposed separation. The nonrandom two-liquid model fitted the experimental data satisfactorily. The model was used in the simulation of a multistage extraction column. m-Cresol recoveries of greater than 97% and m-cresol purity of greater than 99.5% were predicted.« less

Solid and Liquid Waste Drying Bag

NASA Technical Reports Server (NTRS)

Litwiller, Eric (Inventor); Hogan, John A. (Inventor); Fisher, John W. (Inventor)

2009-01-01

Method and system for processing waste from human activities, including solids, liquids and vapors. A fluid-impermeable bag, lined with a liquid-impermeable but vapor-permeable membrane, defining an inner bag, is provided. A vacuum force is provided to extract vapors so that the waste is moved toward a selected region in the inner bag, extracted vapors, including the waste vapors and vaporized portions of the waste liquids are transported across the membrane, and most or all of the solids remain within the liner. Extracted vapors are filtered, and sanitized components thereof are isolated and optionally stored. The solids remaining within the liner are optionally dried and isolated for ultimate disposal.

One-step liquid-liquid extraction of cocaine from urine samples for gas chromatographic analysis.

PubMed

Farina, Marcelo; Yonamine, Maurício; Silva, Ovandir A

2002-07-17

An improved technique for cocaine extraction from urine samples for gas chromatographic (GC) analysis is described. Employing a simple liquid-liquid extraction (LLE) of cocaine with a mixture of ethyl ether:isopropanol (9:1) the method presents a mean recovery of 74.49%. Limit of detection (LOD) and limit of quantification (LOQ) were 5 and 20 ng/ml, respectively. The method is highly precise (coefficient of variation (CV) <8%) and linear from 20 to 2000 ng/ml. It can he applied to detect the presence of cocaine in urine as a marker of its recent use in drug abuse treatment protocols.

Exploring bubble oscillation and mass transfer enhancement in acoustic-assisted liquid-liquid extraction with a microfluidic device

NASA Astrophysics Data System (ADS)

Xie, Yuliang; Chindam, Chandraprakash; Nama, Nitesh; Yang, Shikuan; Lu, Mengqian; Zhao, Yanhui; Mai, John D.; Costanzo, Francesco; Huang, Tony Jun

2015-07-01

We investigated bubble oscillation and its induced enhancement of mass transfer in a liquid-liquid extraction process with an acoustically-driven, bubble-based microfluidic device. The oscillation of individually trapped bubbles, of known sizes, in microchannels was studied at both a fixed frequency, and over a range of frequencies. Resonant frequencies were analytically identified and were found to be in agreement with the experimental observations. The acoustic streaming induced by the bubble oscillation was identified as the cause of this enhanced extraction. Experiments extracting Rhodanmine B from an aqueous phase (DI water) to an organic phase (1-octanol) were performed to determine the relationship between extraction efficiency and applied acoustic power. The enhanced efficiency in mass transport via these acoustic-energy-assisted processes was confirmed by comparisons against a pure diffusion-based process.

State of the art of environmentally friendly sample preparation approaches for determination of PBDEs and metabolites in environmental and biological samples: A critical review.

PubMed

Berton, Paula; Lana, Nerina B; Ríos, Juan M; García-Reyes, Juan F; Altamirano, Jorgelina C

2016-01-28

Green chemistry principles for developing methodologies have gained attention in analytical chemistry in recent decades. A growing number of analytical techniques have been proposed for determination of organic persistent pollutants in environmental and biological samples. In this light, the current review aims to present state-of-the-art sample preparation approaches based on green analytical principles proposed for the determination of polybrominated diphenyl ethers (PBDEs) and metabolites (OH-PBDEs and MeO-PBDEs) in environmental and biological samples. Approaches to lower the solvent consumption and accelerate the extraction, such as pressurized liquid extraction, microwave-assisted extraction, and ultrasound-assisted extraction, are discussed in this review. Special attention is paid to miniaturized sample preparation methodologies and strategies proposed to reduce organic solvent consumption. Additionally, extraction techniques based on alternative solvents (surfactants, supercritical fluids, or ionic liquids) are also commented in this work, even though these are scarcely used for determination of PBDEs. In addition to liquid-based extraction techniques, solid-based analytical techniques are also addressed. The development of greener, faster and simpler sample preparation approaches has increased in recent years (2003-2013). Among green extraction techniques, those based on the liquid phase predominate over those based on the solid phase (71% vs. 29%, respectively). For solid samples, solvent assisted extraction techniques are preferred for leaching of PBDEs, and liquid phase microextraction techniques are mostly used for liquid samples. Likewise, green characteristics of the instrumental analysis used after the extraction and clean-up steps are briefly discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

Thermal stability of liquid antioxidative extracts from pomegranate peel.

PubMed

Qu, Wenjuan; Li, Pingping; Hong, Jihua; Liu, Zhiling; Chen, Yufang; Breksa, Andrew P; Pan, Zhongli

2014-03-30

Liquid extracts from pomegranate peel have the potential for use as natural antioxidant products. This study investigates the quality changes of liquid extracts before and after thermal treatment during sterilization and storage. Liquid pomegranate peel extracts were prepared, sterilized under ultra-high temperature (UHT) at 121 °C for 10 s and then stored at three temperatures (4, 25 and 37 °C) for up to 180 days. The industrial, color, UV-visible spectrum profile and antioxidant (phenolics) characteristics were measured. Thermal sterilization treatment had no negative effects on the industrial, color, spectral and antioxidant characteristics of the extracts. After 180 days, the extracts stored at 4 °C retained 67% of the initial total soluble phenolic content and 58% of the original scavenging activity. The major antioxidant components in the extracts (stored at 4 °C for 180 days) were gallic acid, punicalagin A, punicalagin B and ellagic acid having concentrations of 19.3, 197.2, 221.1 and 92.4 mg L⁻¹, respectively. The results show that liquid pomegranate peel extracts had acceptable thermal stability after sterilization and storage. The recommended storage condition of this product was low temperature. © 2013 Society of Chemical Industry.

Organic solvent-free air-assisted liquid-liquid microextraction for optimized extraction of illegal azo-based dyes and their main metabolite from spices, cosmetics and human bio-fluid samples in one step.

PubMed

Barfi, Behruz; Asghari, Alireza; Rajabi, Maryam; Sabzalian, Sedigheh

2015-08-15

Air-assisted liquid-liquid microextraction (AALLME) has unique capabilities to develop as an organic solvent-free and one-step microextraction method, applying ionic-liquids as extraction solvent and avoiding centrifugation step. Herein, a novel and simple eco-friendly method, termed one-step air-assisted liquid-liquid microextraction (OS-AALLME), was developed to extract some illegal azo-based dyes (including Sudan I to IV, and Orange G) from food and cosmetic products. A series of experiments were investigated to achieve the most favorable conditions (including extraction solvent: 77μL of 1-Hexyl-3-methylimidazolium hexafluorophosphate; sample pH 6.3, without salt addition; and extraction cycles: 25 during 100s of sonication) using a central composite design strategy. Under these conditions, limits of detection, linear dynamic ranges, enrichment factors and consumptive indices were in the range of 3.9-84.8ngmL(-1), 0.013-3.1μgmL(-1), 33-39, and 0.13-0.15, respectively. The results showed that -as well as its simplicity, fastness, and use of no hazardous disperser and extraction solvents- OS-AALLME is an enough sensitive and efficient method for the extraction of these dyes from complex matrices. After optimization and validation, OS-AALLME was applied to estimate the concentration of 1-amino-2-naphthol in human bio-fluids as a main reductive metabolite of selected dyes. Levels of 1-amino-2-naphthol in plasma and urinary excretion suggested that this compound may be used as a new potential biomarker of these dyes in human body. Copyright © 2015 Elsevier B.V. All rights reserved.

Use of experimental design in the investigation of stir bar sorptive extraction followed by ultra-high-performance liquid chromatography-tandem mass spectrometry for the analysis of explosives in water samples.

PubMed

Schramm, Sébastien; Vailhen, Dominique; Bridoux, Maxime Cyril

2016-02-12

A method for the sensitive quantification of trace amounts of organic explosives in water samples was developed by using stir bar sorptive extraction (SBSE) followed by liquid desorption and ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The proposed method was developed and optimized using a statistical design of experiment approach. Use of experimental designs allowed a complete study of 10 factors and 8 analytes including nitro-aromatics, amino-nitro-aromatics and nitric esters. The liquid desorption study was performed using a full factorial experimental design followed by a kinetic study. Four different variables were tested here: the liquid desorption mode (stirring or sonication), the chemical nature of the stir bar (PDMS or PDMS-PEG), the composition of the liquid desorption phase and finally, the volume of solvent used for the liquid desorption. On the other hand, the SBSE extraction study was performed using a Doehlert design. SBSE extraction conditions such as extraction time profiles, sample volume, modifier addition, and acetic acid addition were examined. After optimization of the experimental parameters, sensitivity was improved by a factor 5-30, depending on the compound studied, due to the enrichment factors reached using the SBSE method. Limits of detection were in the ng/L level for all analytes studied. Reproducibility of the extraction with different stir bars was close to the reproducibility of the analytical method (RSD between 4 and 16%). Extractions in various water sample matrices (spring, mineral and underground water) have shown similar enrichment compared to ultrapure water, revealing very low matrix effects. Copyright © 2016 Elsevier B.V. All rights reserved.

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)

EPA Science Inventory

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°...

Hollow Fiber Supported Ionic Liquids Liquid-Phase Micro-extraction Followed by High-Performance Liquid Chromatography for the Determination of Polycyclic Aromatic Hydrocarbons in Milk Samples.

PubMed

Wang, Meng; Cheng, Chunsheng; Liu, Chunbo; Yang, Yaling

2018-01-01

A rapid, simple, reliable and efficient hollow fiber supported ionic liquids liquid-phase micro-extraction method (IL-HF-LPME) followed by high-performance liquid chromatography was successfully applied to the determination of four kinds of polycyclic aromatic hydrocarbons (PAHs) in milk samples. In the IL-HF-LPME method, a mixture of [OMIM]PF6 and lauric acid, in a ratio of 3:1, was immobilized in the pores of a polypropylene hollow fiber used as extraction solvent. A series of essential parameters influencing the extraction efficiency were investigated and optimized. Under the optimal conditions, the extraction equilibrium is achieved within 3 min, the good linearity was >0.9990, the limits of detection varied from 0.14 to 0.71 ng/mL, the limit of quantification values were between 0.4 and 1.8 ng/mL, and the relative standard deviations were in the range of 1.24-3.27% (n = 5). The proposed method was applied to analyze four PAHs in milk samples and recoveries were between 93.6 and 102.8%. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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

PubMed Central

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

Use of Innovative (Micro)Extraction Techniques to Characterise Harpagophytum procumbens Root and its Commercial Food Supplements.

PubMed

Diuzheva, Alina; Carradori, Simone; Andruch, Vasil; Locatelli, Marcello; De Luca, Elisa; Tiecco, Matteo; Germani, Raimondo; Menghini, Luigi; Nocentini, Alessio; Gratteri, Paola; Campestre, Cristina

2018-05-01

For the determination of harpagoside and the wide phenolic pattern in Harpagophytum procumbens root and its commercial food supplements, dispersive liquid-liquid microextraction (DLLME), ultrasound-assisted DLLME (UA-DLLME), and sugaring-out liquid-liquid extraction (SULLE) were tested and compared. In order to optimise the extraction efficiency, DLLME and UA-DLLME were performed in different solvents (water and aqueous solutions of glucose, β-cyclodextrin, (2-hydroxypropyl)-β-cyclodextrin, sodium chloride, natural deep eutectic solvent, and ionic liquid). The plant material was ground and sieved to obtain a uniform granulometry before extraction. Commercial food supplements, containing H. procumbens are commercially available in Italy. The most effective sodium chloride-aided-DLLME was then optimised and applied for analyses followed by HPLC-PDA. For comparison, microwave-assisted extraction was performed using the same solvents and the best results were obtained using 1% of β-cyclodextrin or 15% of sodium chloride. All commercial samples respected the European Pharmacopoeia monograph for this plant material, showing a harpagoside content ≥ 1.2%. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Application of ionic liquid-based dispersive liquid phase microextraction for highly sensitive simultaneous determination of three endocrine disrupting compounds in food packaging.

PubMed

Wang, Lingling; Zhang, Danfeng; Xu, Xu; Zhang, Lei

2016-04-15

Ionic liquid (IL) dispersive liquid-liquid microextraction (DLLME) method was successfully developed for extracting three endocrine disrupting compounds (EDCs) (bisphenol A, bisphenol AF and bisphenol AP) from the food packaging. 1-Octyl-3-methylimidazoliumhexafluorophosphate ([C8MIM][PF6]) was selected as extraction solution. The extraction procedure did not require a dispersive solvent. Three EDCs extraction kinetics were found to be very fast and the equilibrium was attained within 3.0 min following the pseudo-first-order model. The H-bonding and hydrophobic interactions play an important role in the partitioning of EDCs into IL from aqueous solution. The recovered IL could be reused for three runs without significant loss of extraction efficiencies. The spiked recoveries of three targets in food packaging were in the range of 97.8-103.1%. The limits of detection ranged from 0.50 to 1.50 ng mL(-1) (S/N=3). As a result, this method has been successfully applied for the sensitive detection of three EDCs in real samples. Copyright © 2015 Elsevier Ltd. All rights reserved.

Centrifugeless dispersive liquid-liquid microextraction based on salting-out phenomenon followed by high performance liquid chromatography for determination of Sudan dyes in different species.

PubMed

Bazregar, Mohammad; Rajabi, Maryam; Yamini, Yadollah; Arghavani-Beydokhti, Somayeh; Asghari, Alireza

2018-04-01

In this work, a novel method, namely centrifugeless dispersive liquid-liquid microextraction, is introduced for the efficient extraction of banned Sudan dyes from foodstuff and water samples. In this method, which is based upon the salting-out phenomenon, in order to accelerate the extraction process, the extraction solvent (1-undecanol, 75 μL) is dispersed into the sample solution. Then the mixture is passed through a small column filled with 5 g sodium chloride, used as a separating reagent. In this condition, fine droplets of the extraction solvent are floated on the mixture, and the phase separation is simply achieved. This method is environmentally friendly, simple, and very fast, so that the overall extraction time is only 7 min. Under the optimal experimental conditions, the preconcentration factors in the range of 90-121 were obtained for the analytes. Also good linearities were obtained in the range of 2.5-1200 ng mL -1 (r 2  ≥ 0.993). Copyright © 2017 Elsevier Ltd. All rights reserved.

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

PubMed

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

2018-01-01

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

Aromatics extraction from pyrolytic sugars using ionic liquid to enhance sugar fermentability.

PubMed

Li, Xiaohua; Luque-Moreno, Luis C; Oudenhoven, Stijn R G; Rehmann, Lars; Kersten, Sascha R A; Schuur, Boelo

2016-09-01

Fermentative bioethanol production from pyrolytic sugars was improved via aromatics removal by liquid-liquid extraction. As solvents, the ionic liquid (IL) trihexyltetradecylphosphonium dicyanamide (P666,14[N(CN)2]) and ethyl acetate (EA) were compared. Two pyrolytic sugar solutions were created from acid-leached and untreated pinewood, with levoglucosan contents (most abundant sugar) of 29.0% and 8.3% (w/w), respectively. In a single stage extraction, 70% of the aromatics were effectively removed by P666,14[N(CN)2] and 50% by EA, while no levoglucosan was extracted. The IL was regenerated by vacuum evaporation (100mbar) at 220°C, followed by extraction of aromatics from fresh pyrolytic sugar solutions. Regenerated IL extracted aromatics with similar extraction efficiency as the fresh IL, and the purified sugar fraction from pretreated pinewood was hydrolyzed to glucose and fermented to ethanol, yielding 0.46g ethanol/(g glucose), close to the theoretical maximum yield. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Ultrasound-assisted magnetic solid-phase extraction based ionic liquid-coated Fe3O4@graphene for the determination of nitrobenzene compounds in environmental water samples.

PubMed

Cao, Xiaoji; Shen, Lingxiao; Ye, Xuemin; Zhang, Feifei; Chen, Jiaoyu; Mo, Weimin

2014-04-21

An ultrasound-assisted magnetic solid-phase extraction procedure with the [C7MIM][PF6] ionic liquid-coated Fe3O4-grafted graphene nanocomposite as the magnetic adsorbent has been developed for the determination of five nitrobenzene compounds (NBs) in environmental water samples, in combination with high performance liquid chromatography-photodiode array detector (HPLC-PDA). Several significant factors that affect the extraction efficiency, such as the types of magnetic nanoparticle and ionic liquid, the volume of ionic liquid and the amount of magnetic nanoparticles, extraction time, ionic strength, and solution pH, were investigated. With the assistance of ultrasound, adsorbing nitrobenzene compounds by ionic liquid and self-aggregating ionic liquid onto the surface of the Fe3O4-grafted graphene proceeded synchronously, which made the extraction achieved the maximum within 20 min using only 144 μL [C7MIM][PF6] and 3 mg Fe3O4-grafted graphene. Under the optimized conditions, satisfactory linearities were obtained for all NBs with correlation coefficients larger than 0.9990. The mean recoveries at two spiked levels ranged from 80.35 to 102.77%. Attributed to the convenient magnetic separation, the Fe3O4-grafted graphene could be recycled many times. The proposed method was demonstrated to be feasible, simple, solvent-saving and easy to operate for the trace analysis of NBs in environmental water samples.

In-situ ionic liquid dispersive liquid-liquid microextraction using a new anion-exchange reagent combined Fe3O4 magnetic nanoparticles for determination of pyrethroid pesticides in water samples.

PubMed

Fan, Chen; Liang, You; Dong, Hongqiang; Ding, Guanglong; Zhang, Wenbing; Tang, Gang; Yang, Jiale; Kong, Dandan; Wang, Deng; Cao, Yongsong

2017-07-04

In this work, in-situ ionic liquid dispersive liquid-liquid microextraction combined ultrasmall Fe 3 O 4 magnetic nanoparticles was developed as a kind of pretreatment method to detect pyrethroid pesticides in water samples. New anion-exchange reagents including Na[DDTC] and Na[N(CN) 2 ] were optimized for in-situ extraction pyrethroids, which showed enhanced microextraction performance. Pyrethroids were enriched by hydrophilic ionic liquid [P 4448 ][Br] (aqueous solution, 200 μL, 0.2 mmol mL -1 ) reaction in-situ with anion-exchange reagent Na[N(CN) 2 ] (aqueous solution, 300 μL, 0.2 mmol mL -1 ) forming hydrophobic ionic liquid as extraction agent in water sample (10 mL). Ultrasmall superparamagnetic iron oxide nanoparticles (30 mg) were used to collect the mixture of ionic liquid and pyrethroids followed by elution with acetonitrile. The extraction of ionic liquid strategies was unique and efficiently fulfilled with high enrichment factors (176-213) and good recoveries (80.20-117.31%). The method was successively applied to the determination of pyrethroid pesticides in different kinds of water samples with the limits of detection ranged from 0.16 to 0.21 μg L -1 . The proposed method is actually nanometer-level microextraction (average size 80 nm) with the advantages of simplicity, rapidity, and sensitivity. Copyright © 2017 Elsevier B.V. All rights reserved.

Ionic-liquid-based dispersive liquid-liquid microextraction coupled with high-performance liquid chromatography for the forensic determination of methamphetamine in human urine.

PubMed

Wang, Ruifeng; Qi, Xiujuan; Zhao, Lei; Liu, Shimin; Gao, Shuang; Ma, Xiangyuan; Deng, Youquan

2016-07-01

Determination of methamphetamine in forensic laboratories is a major issue due to its health and social harm. In this work, a simple, sensitive, and environmentally friendly method based on ionic liquid dispersive liquid-liquid microextraction combined with high-performance liquid chromatography was established for the analysis of methamphetamine in human urine. 1-Octyl-3-methylimidazolium hexafluorophosphate with the help of disperser solvent methanol was selected as the microextraction solvent in this process. Various parameters affecting the extraction efficiency of methamphetamine were investigated systemically, including extraction solvent and its volume, disperser solvent and its volume, sample pH, extraction temperature, and centrifugal time. Under the optimized conditions, a good linearity was obtained in the concentration range of 10-1000 ng/mL with determination coefficient >0.99. The limit of detection calculated at a signal-to-noise ratio of 3 was 1.7 ng/mL and the relative standard deviations for six replicate experiments at three different concentration levels of 100, 500, and 1000 ng/mL were 6.4, 4.5, and 4.7%, respectively. Meanwhile, up to 220-fold enrichment factor of methamphetamine and acceptable extraction recovery (>80.0%) could be achieved. Furthermore, this method has been successfully employed for the sensitive detection of a urine sample from a suspected drug abuser. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis, Characterization and Application of 1-Butyl-3 Methylimidazolium Chloride as Green Material for Extractive Desulfurization of Liquid Fuel

PubMed Central

Dharaskar, Swapnil A.; Varma, Mahesh N.; Shende, Diwakar Z.; Yoo, Chang Kyoo; Wasewar, Kailas L.

2013-01-01

The possible application of imidazolium ionic liquids as energy-efficient green material for extractive deep desulfurization of liquid fuel has been investigated. 1-Butyl-3-methylimidazolium chloride [BMIM]Cl was synthesized by nucleophilic substitution reaction of n-methylimidazolium and 1-chlorobutane. Molecular structures of the ILs were confirmed by FTIR, 1H-NMR, and 13C-NMR. The thermal properties, conductivity, solubility, water content and viscosity analysis of [BMIM]Cl were carried out. The effects of reaction time, reaction temperature, sulfur compounds, and recycling of IL without regeneration on dibenzothiophene removal of liquid fuel were presented. In the extractive desulfurization process, the removal of dibenzothiophene in n-dodecane using [BMIM]Cl was 81% with mass ratio of 1 : 1, in 30 min at 30°C under the mild reaction conditions. Also, desulfurization of real fuels with IL and multistage extraction were studied. The results of this work might offer significant insights in the perceptive use of imidazoled ILs as energy-efficient green material for extractive deep desulfurization of liquid fuels as it can be reused without regeneration with considerable extraction efficiency. PMID:24307868

Separations by supported liquid membrane cascades

DOEpatents

Danesi, Pier R.

1986-01-01

The invention describes a new separation technique which leads to multi-stage operations by the use of a series (a cascade) of alternated carrier-containing supported-liquid membranes. The membranes contain alternatively a liquid cation exchanger extractant and a liquid anion exchanger extractant (or a neutral extractant) as carrier. The membranes are spaced between alternated aqueous electrolytic solutions of different composition which alternatively provide positively charged extractable species and negatively charged (or zero charged) extractable species, of the chemical species to be separated. The alternated aqueous electrolytic solutions in addition to providing the driving force to the process, simultaneously function as a stripping solution from one type of membrane and as an extraction-promoting solution for the other type of membrane. The aqueous electrolytic solutions and the supported liquid membranes are arranged in such a way to provide a continuous process which leads to the continuous enrichment of the species which show the highest permeability coefficients. By virtue of the very high number of stages which can be arranged, even chemical species having very similar chemical behavior (and consequently very similar permeability coefficients) can be completely separated. The invention also provide a way to concentrate the separated species.

The influence of purge times on the yields of essential oil components extracted from plants by pressurized liquid extraction.

PubMed

Wianowska, Dorota

2014-01-01

The influence of different purge times on the yield of the main essential oil constituents of rosemary (Rosmarinus officinalis L.), thyme (Thymus vulgaris L.), and chamomile (Chamomilla recutita L.) was investigated. The pressurized liquid extraction process was performed by applying different extraction temperatures and solvents. The results presented in the paper show that the estimated yield of essential oil components extracted from the plants in the pressurized liquid extraction process is purge time-dependent. The differences in the estimated yields are mainly connected with the evaporation of individual essential oil components and the applied solvent during the purge; the more volatile an essential oil constituent is, the greater is its loss during purge time, and the faster the evaporation of the solvent during the purge process is, the higher the concentration of less volatile essential oil components in the pressurized liquid extraction receptacle. The effect of purge time on the estimated yield of individual essential oil constituents is additionally differentiated by the extraction temperature and the extraction ability of the applied solvent.

17 CFR 210.4-10 - Financial accounting and reporting for oil and gas producing activities pursuant to the Federal...

Code of Federal Regulations, 2013 CFR

2013-04-01

... natural gas liquids, or natural gas (“oil and gas”) in their natural states and original locations; (B... processing gas to extract liquid hydrocarbons); and (D) Extraction of saleable hydrocarbons, in the solid... production function as: a. The first point at which oil, gas, or gas liquids, natural or synthetic, are...

17 CFR 210.4-10 - Financial accounting and reporting for oil and gas producing activities pursuant to the Federal...

Code of Federal Regulations, 2012 CFR

2012-04-01

... natural gas liquids, or natural gas (“oil and gas”) in their natural states and original locations; (B... processing gas to extract liquid hydrocarbons); and (D) Extraction of saleable hydrocarbons, in the solid... production function as: a. The first point at which oil, gas, or gas liquids, natural or synthetic, are...

Determination of trace mercury in water based on N-octylpyridinium ionic liquids preconcentration and stripping voltammetry.

PubMed

Li, Zhenhan; Xia, Shanhong; Wang, Jinfen; Bian, Chao; Tong, Jianhua

2016-01-15

A novel method for determination of trace mercury in water is developed. The method is performed by extracting mercury firstly with ionic liquids (ILs) and then detecting the concentration of mercury in organic media with anodic stripping voltammetry. Liquid-liquid extraction of mercury(II) ions by four ionic liquids with N-octylpyridinium cations ([OPy](+)) was studied. N-octylpyridinium tetrafluoroborate and N-octylpyridinium trifluoromethylsulfonate were found to be efficient and selective extractant for mercury. Temperature controlled dispersive liquid phase microextraction (TC-DLPME) technique was utilized to improve the performance of preconcentration. After extraction, precipitated IL was diluted by acetonitrile buffer and mercury was detected by differential pulse stripping voltammetry (DPSV) with gold disc electrode. Mercury was enriched by 17 times while interfering ions were reduced by two orders of magnitude in the organic media under optimum condition. Sensitivity and selectivity for electrochemical determination of mercury were improved by using the proposed method. Tap, pond and waste water samples were analyzed with recoveries ranging from 81% to 107% and detection limit of 0.05 μg/L. Copyright © 2015 Elsevier B.V. All rights reserved.

Ultra-high-pressure liquid chromatography-tandem mass spectrometry method for the determination of alkylphenols in soil.

PubMed

Wang, Jing; Pan, Hefang; Liu, Zhengzheng; Ge, Fei

2009-03-20

A novel method has been developed for the determination of alkylphenols in soil by ultra-high-pressure liquid chromatography employing small particle sizes, combined with tandem mass spectrometry. Soil samples were extracted with pressurized liquid extraction (PLE) and then cleaned with solid-phase extraction (SPE). The extracts were separated on C18 column (1.7 microm, 50 mm x 2.1mm) with a gradient elution and a mobile phase consisting of water and acetonitrile, and then detected by an electrospray ionization tandem mass spectrometry in negative ion mode with multiple reaction monitoring (MRM). Compared with traditional liquid chromatography, it took ultra-high-pressure liquid chromatography much less time to analyze alkylphenols. Additionally, the ultra-high-pressure liquid chromatography/tandem mass spectrometry method produces satisfactory reliability, sensitivity, and accuracy. The average recoveries of the three target analytes were 74.0-103.4%, with the RSD<15%. The calibration curves for alkylphenols were linear within the range of 0.01-0.4 microg/ml, with the correlation coefficients greater than 0.99. When 10 g soil sample was used for analysis, the limits of quantification (LOQs) of the three alkylphenols were all 1.0 microg/kg.

Simultaneous determination of brazilin and protosappanin B in Caesalpinia sappan by ionic-liquid dispersive liquid-phase microextraction method combined with HPLC.

PubMed

Xia, Zhaoyang; Li, Dongdong; Li, Qing; Zhang, Yan; Kang, Wenyi

2017-11-13

The conditions of heating, ionic liquid-based ultrasonic-assisted extraction combined with reverse-phase high performance liquid chromatography were optimized to simultaneously isolate and determinate brazilin and protosappanin B in Caesalpinia sappan. Ionic liquids, including [BMIM]Br, [BMIM]BF 4 , [BMIM]PF 6 and [HMIM]PF 6 , were selected as extraction solvents while methanol, acetone, acetonitrile, ethanol and water were selected as dispersants. The chromatographic column was Purospher star RP-C 18 (250 mm × 4.6 mm, 5 μm), a mixture of methanol and 0.2% phosphoric acid-water was used as mobile phase at a flow rate 0.65 mL/min. The result displayed that the extraction yields of brazilin and protosappanin B were highest when the concentration of [BMIM]Br methanol solution as extraction solvent was 0.5 mol/L and the solid-liquid ratio was 1:50 (g/mL). Under the optimal extraction conditions, the contents of brazilin showed a good linearity (r = 1.0000) within the range of 1.25-7.50 μg with the average recovery of 99.33%, the contents of protosappanin B also showed a good linearity (r = 0.9999) within the range of 0.50-3.00 μg with the average recovery of 98.31%. This experiment, which adopted environmentally friendly reagent as extraction solvent, not only improved the extraction efficiency, but also avoided the environmental pollution caused by organic solvent. Moreover, it was simple and reliable, and can be of important significance in the study of Traditional Chinese Medicine active ingredient extraction methods. The antibacterial activities of the ionic liquids and methanol extracts were determined using the paper disc diffusion method. The ionic liquid extract was found to possess antibacterial activity against Staphylococcus aureus and methicillin-resistant S. aureus (MIC value of 37.5 mg crude drug/mL), β-Lactamase producing S. aureus (MIC values of 18.8 mg crude drug/mL), but not against E. coli, Extended spectrum β-Lactamases E. coli and P. aeruginosa. Compared with the ionic liquid extract, the methanol extract was found to have antibacterial activity against S. aureus and methicillin-resistant S. aureus (MIC value of 75.0 mg crude drug/mL), β-Lactamase producing S. aureus (MIC values of 150.0 mg crude drug/mL). However, the same, the methanol extract did not have antibacterial activity against E. coli, Extended spectrum β-Lactamases E. coli and P. aeruginosa.

IMPROVEMENTS IN LIQUID-LIQUID EXTRACTION APPARATUS

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1961-06-28

A description is given of a liquid-liquid extraction apparatus and of the method of effecting a net transportation in opposed directions of a heavy liquid and a light liquid. The apparatus consists of a plurality of series- connected ves sels, inlet and outlet means for the phases at the ends, and a pulsing means. The upper part of one vessel is joined to the lower part of the next vessel by one connection line or a plurality of parallel-connected lines. The lower part of the second vessel is below the upper part of the first vessel. The volume of eachmore » connection line is less than or the same as the volume displaced by one stroke of the pulsing means. The method is characterized in that a mixture of both liquids is caused to flow to and fro between adjacent vessels through the connection lines which joins the vessels. (N.W.R.)« less

Ionic liquid-modified materials for solid-phase extraction and separation: a review.

PubMed

Vidal, Lorena; Riekkola, Marja-Liisa; Canals, Antonio

2012-02-17

In recent years, materials science has propelled to the research forefront. Ionic liquids with unique and fascinating properties have also left their footprints to the developments of materials science during the last years. In this review we highlight some of their recent advances and provide an overview at the current status of ionic liquid-modified materials applied in solid-phase extraction, liquid and gas chromatography and capillary electrochromatography with reference to recent applications. In addition, the potential of ionic liquids in the modification of capillary inner wall in capillary electrophoresis is demonstrated. The main target material modified with ionic liquids is silica, but polymers and monoliths have recently joined the studies. Although imidazolium is still clearly the most commonly used ionic liquid for the covalently modification of materials, the exploitation of pyridinium and phosphonium will most probably increase in the future. Copyright © 2011 Elsevier B.V. All rights reserved.

Room-temperature ionic liquids as replacements for organic solvents in multiphase bioprocess operations.

PubMed

Cull, S G; Holbrey, J D; Vargas-Mora, V; Seddon, K R; Lye, G J

2000-07-20

Organic solvents are widely used in a range of multiphase bioprocess operations including the liquid-liquid extraction of antibiotics and two-phase biotransformation reactions. There are, however, considerable problems associated with the safe handling of these solvents which relate to their toxic and flammable nature. In this work we have shown for the first time that room-temperature ionic liquids, such as 1-butyl-3-methylimi- dazolium hexafluorophosphate, [bmim][PF(6)], can be successfully used in place of conventional solvents for the liquid-liquid extraction of erythromycin-A and for the Rhodococcus R312 catalyzed biotransformation of 1, 3-dicyanobenzene (1,3-DCB) in a liquid-liquid, two-phase system. Extraction of erythromycin with either butyl acetate or [bmim][PF(6)] showed that values of the equilibrium partition coefficient, K, up to 20-25 could be obtained for both extractants. The variation of K with the extraction pH was also similar in the pH range 5-9 though differed significantly at higher pH values. Biotransformation of 1,3-DCB in both water-toluene and water-[bmim][PF(6)] systems showed similar profiles for the conversion of 1,3-DCB initially to 3-cyanobenzamide and then 3-cyanobenzoic acid. The initial rate of 3-cyanobenzamide production in the water-[bmim][PF(6)] system was somewhat lower, however, due to the reduced rate of 1,3-DCB mass transfer from the more viscous [bmim] [PF(6)] phase. It was also shown that the specific activity of the biocatalyst in the water-[bmim] [PF(6)] system was almost an order of magnitude greater than in the water-toluene system which suggests that the rate of 3-cyanobenzamide production was limited by substrate mass transfer rather than the activity of the biocatalyst. Copyright 2000 John Wiley & Sons, Inc.

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.

PubMed

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.

Exploring bubble oscillation and mass transfer enhancement in acoustic-assisted liquid-liquid extraction with a microfluidic device

PubMed Central

Xie, Yuliang; Chindam, Chandraprakash; Nama, Nitesh; Yang, Shikuan; Lu, Mengqian; Zhao, Yanhui; Mai, John D.; Costanzo, Francesco; Huang, Tony Jun

2015-01-01

We investigated bubble oscillation and its induced enhancement of mass transfer in a liquid-liquid extraction process with an acoustically-driven, bubble-based microfluidic device. The oscillation of individually trapped bubbles, of known sizes, in microchannels was studied at both a fixed frequency, and over a range of frequencies. Resonant frequencies were analytically identified and were found to be in agreement with the experimental observations. The acoustic streaming induced by the bubble oscillation was identified as the cause of this enhanced extraction. Experiments extracting Rhodanmine B from an aqueous phase (DI water) to an organic phase (1-octanol) were performed to determine the relationship between extraction efficiency and applied acoustic power. The enhanced efficiency in mass transport via these acoustic-energy-assisted processes was confirmed by comparisons against a pure diffusion-based process. PMID:26223474

Method for treating liquid wastes

DOEpatents

Katti, K.V.; Volkert, W.A.; Singh, P.; Ketring, A.R.

1995-12-26

The method of treating liquid waste in a media is accomplished by exposing the media to phosphinimines and sequestering {sup 99}Tc from the media by the phosphinimine (PN) functionalities. The system for treating the liquid waste in the media includes extraction of {sup 99}TcO{sub 4}{sup {minus}} from aqueous solutions into organic solvents or mixed organic/polar media, extraction of {sup 99}Tc from solutions on a solid matrix by using a container containing PN functionalities on solid matrices including an inlet and outlet for allowing flow of media through an immobilized phosphinimine ligand system contained within the container. Also, insoluble suspensions of phosphinimine functionalities on solid matrices in liquid solutions or present on supported liquid membranes (SLM) can be used to sequester {sup 99}Tc from those liquids. 6 figs.

Method for treating liquid wastes

DOEpatents

Katti, Kattesh V.; Volkert, Wynn A.; Singh, Prahlad; Ketring, Alan R.

1995-01-01

The method of treating liquid waste in a media is accomplished by exposing the media to phosphinimines and sequestering .sup.99 Tc from the media by the phosphinimine (PN) functionalities. The system for treating the liquid waste in the media includes extraction of .sup.99 TcO.sub.4.sup.- from aqueous solutions into organic solvents or mixed organic/polar media, extraction of .sup.99 Tc from solutions on a solid matrix by using a container containing PN functionalities on solid matrices including an inlet and outlet for allowing flow of media through an immobilized phosphinimine ligand system contained within the container. Also, insoluble suspensions of phosphinimine functionalities on solid matrices in liquid solutions or present on supported liquid membranes (SLM) can be used to sequester .sup.99 Tc from those liquids.

Integration of phase separation with ultrasound-assisted salt-induced liquid-liquid microextraction for analyzing the fluoroquinones in human body fluids by liquid chromatography.

PubMed

Wang, Huili; Gao, Ming; Wang, Mei; Zhang, Rongbo; Wang, Wenwei; Dahlgren, Randy A; Wang, Xuedong

2015-03-15

Herein, we developed a novel integrated device to perform phase separation based on ultrasound-assisted salt-induced liquid-liquid microextraction for determination of five fluoroquinones (FQs) in human body fluids. The integrated device consisted of three simple HDPE components used to separate the extraction solvent from the aqueous phase prior to retrieving the extractant. A series of extraction parameters were optimized using the response surface method based on central composite design. Optimal conditions consisted of 945μL acetone extraction solvent, pH 2.1, 4.1min stir time, 5.9g Na2SO4, and 4.0min centrifugation. Under optimized conditions, the limits of detection (at S/N=3) were 0.12-0.66μgL(-1), the linear range was 0.5-500μgL(-1) and recoveries were 92.6-110.9% for the five FQs extracted from plasma and urine. The proposed method has several advantages, such as easy construction from inexpensive materials, high extraction efficiency, short extraction time, and compatibility with HPLC analysis. Thus, this method shows excellent prospects for sample pretreatment and analysis of FQs in human body fluids. Copyright © 2015 Elsevier B.V. All rights reserved.

Direct extraction of genomic DNA from maize with aqueous ionic liquid buffer systems for applications in genetically modified organisms analysis.

PubMed

Gonzalez García, Eric; Ressmann, Anna K; Gaertner, Peter; Zirbs, Ronald; Mach, Robert L; Krska, Rudolf; Bica, Katharina; Brunner, Kurt

2014-12-01

To date, the extraction of genomic DNA is considered a bottleneck in the process of genetically modified organisms (GMOs) detection. Conventional DNA isolation methods are associated with long extraction times and multiple pipetting and centrifugation steps, which makes the entire procedure not only tedious and complicated but also prone to sample cross-contamination. In recent times, ionic liquids have emerged as innovative solvents for biomass processing, due to their outstanding properties for dissolution of biomass and biopolymers. In this study, a novel, easily applicable, and time-efficient method for the direct extraction of genomic DNA from biomass based on aqueous-ionic liquid solutions was developed. The straightforward protocol relies on extraction of maize in a 10 % solution of ionic liquids in aqueous phosphate buffer for 5 min at room temperature, followed by a denaturation step at 95 °C for 10 min and a simple filtration to remove residual biopolymers. A set of 22 ionic liquids was tested in a buffer system and 1-ethyl-3-methylimidazolium dimethylphosphate, as well as the environmentally benign choline formate, were identified as ideal candidates. With this strategy, the quality of the genomic DNA extracted was significantly improved and the extraction protocol was notably simplified compared with a well-established method.

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

PubMed

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

2018-01-15

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

Solidification of floating organic droplet in dispersive liquid-liquid microextraction as a green analytical tool.

PubMed

Mansour, Fotouh R; Danielson, Neil D

2017-08-01

Dispersive liquid-liquid microextraction (DLLME) is a special type of microextraction in which a mixture of two solvents (an extracting solvent and a disperser) is injected into the sample. The extraction solvent is then dispersed as fine droplets in the cloudy sample through manual or mechanical agitation. Hence, the sample is centrifuged to break the formed emulsion and the extracting solvent is manually separated. The organic solvents commonly used in DLLME are halogenated hydrocarbons that are highly toxic. These solvents are heavier than water, so they sink to the bottom of the centrifugation tube which makes the separation step difficult. By using solvents of low density, the organic extractant floats on the sample surface. If the selected solvent such as undecanol has a freezing point in the range 10-25°C, the floating droplet can be solidified using a simple ice-bath, and then transferred out of the sample matrix; this step is known as solidification of floating organic droplet (SFOD). Coupling DLLME to SFOD combines the advantages of both approaches together. The DLLME-SFOD process is controlled by the same variables of conventional liquid-liquid extraction. The organic solvents used as extractants in DLLME-SFOD must be immiscible with water, of lower density, low volatility, high partition coefficient and low melting and freezing points. The extraction efficiency of DLLME-SFOD is affected by types and volumes of organic extractant and disperser, salt addition, pH, temperature, stirring rate and extraction time. This review discusses the principle, optimization variables, advantages and disadvantages and some selected applications of DLLME-SFOD in water, food and biomedical analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

Method and turbine for extracting kinetic energy from a stream of two-phase fluid

NASA Technical Reports Server (NTRS)

Elliott, D. G. (Inventor)

1979-01-01

An axial flow separator turbine is described which includes a number of nozzles for delivering streams of a two-phase fluid along linear paths. A phase separator which responsively separates the vapor and liquid is characterized by concentrically related annuli supported for rotation within the paths. The separator has endless channels for confining the liquid under the influence of centrifugal forces. A vapor turbine fan extracts kinetic energy from the liquid. Angular momentum of both the liquid phase and the vapor phase of the fluid is converted to torque.

Enantioselective analysis of chiral anteiso fatty acids in the polar and neutral lipids of food.

PubMed

Hauff, Simone; Hottinger, Georg; Vetter, Walter

2010-04-01

Anteiso fatty acids (aFA) are substituted with a methyl group on the antepenultimate carbon of the straight acyl chain. This feature leads to a stereogenic center. The 12-methyltetradecanoic acid (a15:0) and the 14-methylhexadecanoic acid (a17:0) are the most common aFA found in food, although they occur only in very small quantities. In this study we used gas chromatography in combination with a chiral stationary phase to determine the enantiomeric distribution of both a15:0 and a17:0 in the neutral and polar lipids of aquatic food samples and cheese. The best suited column was selected out of four custom-made combinations of heptakis(6-O-tert-butyldimethylsilyl-2,3-di-O-methyl)-beta-cyclodextrin (beta-TBDM) with different amount and polarity of an achiral polysiloxane. After separation of polar and neutral lipids of the food samples by solid phase extraction, fatty acid methyl esters were prepared and the fatty acid methyl esters were fractionated by reversed phase high performance liquid chromatography. Measurements of fractions high in aFA by enantioselective GC/MS in the selected ion monitoring mode verified the dominance of the (S)-enantiomers of a15:0 and a17:0 in both lipid fractions. However (R)-enantiomers were detectable in all samples. The relative proportion of the (R)-enantiomers was up to fivefold higher in the polar lipids than in the neutral lipids. The higher proportions in the polar lipids indicate that microorganisms might be involved in the formation of (R)-aFA.

Ionic liquid-based ultrasound-assisted emulsification microextraction coupled with high performance liquid chromatography for the determination of four fungicides in environmental water samples.

PubMed

Liang, Pei; Wang, Fang; Wan, Qin

2013-02-15

A highly efficient and environmentally friendly sample preparation method termed ionic liquid-based ultrasound-assisted emulsification microextraction (IL-USAEME) combined with high performance liquid chromatography has been developed for the determination of four fungicides (azoxystrobin, diethofencarb, pyrimethanil and kresoxim-methyl) in water samples. In this novel approach, ionic liquid (IL) was used as extraction solvent in place of the organic solvent used in conventional USAEME assay, and there is no need for using organic dispersive solvent which is typically required in the common dispersive liquid-liquid microextraction method. Various parameters that affect the extraction efficiency, such as the kind and volume of IL, ultrasound emulsification time, extraction temperature and salt addition were investigated and optimized. Under the optimum extraction condition, the linearities of calibration curves were in the range from 3 to 5000 ng mL(-1) for target analytes with the correlation coefficient higher than 0.9992. The enrichment factors and the limits of detection were in the range of 88-137 and 0.73-2.2 ng mL(-1), depending on the analytes. The environmental water samples were successfully analyzed using the proposed method, and the relative recoveries at fortified levels of 50 and 100 ng mL(-1) were in the range of 83.9%-116.2%. Copyright © 2012 Elsevier B.V. All rights reserved.

A dispersive liquid-liquid micellar microextraction for the determination of pharmaceutical compounds in wastewaters using ultra-high-performace liquid chromatography with DAD detection.

PubMed

Montesdeoca-Esponda, Sarah; Mahugo-Santana, Cristina; Sosa-Ferrera, Zoraida; Santana-Rodríguez, José Juan

2015-03-01

A dispersive liquid-liquid micellar microextraction (DLLMME) method coupled with ultra-high-performance liquid chromatography (UHPLC) using Diode Array Detector (DAD) detector was developed for the analysis of five pharmaceutical compounds of different nature in wastewaters. A micellar solution of a surfactant, polidocanol, as extraction solvent (100 μL) and chloroform as dispersive solvent (200 μL) were used to extract and preconcentrate the target analytes. Samples were heated above critical temperature and the cloudy solution was centrifuged. After removing the chloroform, the reduced volume of surfactant was then injected in the UHPLC system. In order to obtain high extraction efficiency, the parameters affecting the liquid-phase microextraction, such as time and temperature extraction, ionic strength and surfactant and organic solvent volume, were optimized using an experimental design. Under the optimized conditions, this procedure allows enrichment factors of up to 47-fold. The detection limit of the method ranged from 0.1 to 2.0 µg/L for the different pharmaceuticals. Relative standard deviations were <26% for all compounds. The procedure was applied to samples from final effluent collected from wastewater treatment plants in Las Palmas de Gran Canaria (Spain), and two compounds were measured at 67 and 113 µg/L in one of them. Copyright © 2014 John Wiley & Sons, Ltd.

Removing Biostatic Agents From Fermentation Solutions

NASA Technical Reports Server (NTRS)

Du Fresne, E. R.

1984-01-01

Liquid carbon dioxide inexpensive solvent. Inexpensive process proposed for removing such poisons as furfural and related compounds from fermentation baths of biomass hydrolysates. New process based on use of liquid carbon dioxide as extraction solvent. Liquid CO2 preferable to such other liquid solvents as ether or methylene chloride.

Determination of Carvedilol Enantiomers in Pharmaceutical Dosages by SBSE-HPLC Based on Diastereomer Formation.

PubMed

Taraji, Maryam; Talebpour, Zahra; Adib, Nuoshin; Karimi, Shima; Haghighi, Farideh; Aboul-Enein, Hassan Y

2015-09-01

A sensitive, selective and simple method for the simultaneous determination of carvedilol enantiomers in aqueous solution has been developed using stir bar sorptive extraction (SBSE) followed by high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection. This method is based on the reaction of carvedilol enantiomers with (-)-menthyl chloroformate (MCF) after extraction by the SBSE method to produce diastereomeric derivatives. The separation was achieved by use of a C18 analytical column and the influence of mobile phase composition on the enantioseparation of carvedilol was studied. The applicability of two sorptive phases, poly(methyl methacrylate/ethyleneglycol dimethacrylate) (PA-EG) and polydimethylsiloxane, were tested for extraction of carvedilol enantiomers from aqueous samples. The obtained results showed excellent linear dynamic ranges and precisions for each of them. The least limit of detection for (S)- and (R)-carvedilol obtained 8 and 11 µg L(-1), respectively, using the PA-EG sorptive phase. Inter- and intra-mean recoveries were also satisfactory, ranging from 98 to 103%, with coefficient of variation in the range of 1-5% at three fortified levels using a PA-EG coated stir bar. The proposed SBSE (PA-EG)-MCF derivatization-HPLC-UV method was successfully applied to enantioselective analysis of carvedilol in water and pharmaceutical dosages, confirming the application of this method. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Headspace single drop microextraction versus dispersive liquid-liquid microextraction using magnetic ionic liquid extraction solvents.

PubMed

An, Jiwoo; Rahn, Kira L; Anderson, Jared L

2017-05-15

A headspace single drop microextraction (HS-SDME) method and a dispersive liquid-liquid microextraction (DLLME) method were developed using two tetrachloromanganate ([MnCl 4 2- ])-based magnetic ionic liquids (MIL) as extraction solvents for the determination of twelve aromatic compounds, including four polyaromatic hydrocarbons, by reversed phase high-performance liquid chromatography (HPLC). The analytical performance of the developed HS-SDME method was compared to the DLLME approach employing the same MILs. In the HS-SDME approach, the magnetic field generated by the magnet was exploited to suspend the MIL solvent from the tip of a rod magnet. The utilization of MILs in HS-SDME resulted in a highly stable microdroplet under elevated temperatures and long extraction times, overcoming a common challenge encountered in traditional SDME approaches of droplet instability. The low UV absorbance of the [MnCl 4 2- ]-based MILs permitted direct analysis of the analyte enriched extraction solvent by HPLC. In HS-SDME, the effects of ionic strength of the sample solution, temperature of the extraction system, extraction time, stir rate, and headspace volume on extraction efficiencies were examined. Coefficients of determination (R 2 ) ranged from 0.994 to 0.999 and limits of detection (LODs) varied from 0.04 to 1.0μgL -1 with relative recoveries from lake water ranging from 70.2% to 109.6%. For the DLLME method, parameters including disperser solvent type and volume, ionic strength of the sample solution, mass of extraction solvent, and extraction time were studied and optimized. Coefficients of determination for the DLLME method varied from 0.997 to 0.999 with LODs ranging from 0.05 to 1.0μgL -1 . Relative recoveries from lake water samples ranged from 68.7% to 104.5%. Overall, the DLLME approach permitted faster extraction times and higher enrichment factors for analytes with low vapor pressure whereas the HS-SDME approach exhibited better extraction efficiencies for analytes with relatively higher vapor pressure. Copyright © 2017 Elsevier B.V. All rights reserved.

Partition coefficients of organic compounds between water and imidazolium-, pyridinium-, and phosphonium-based ionic liquids.

PubMed

Padró, Juan M; Pellegrino Vidal, Rocío B; Reta, Mario

2014-12-01

The partition coefficients, P IL/w, of several compounds, some of them of biological and pharmacological interest, between water and room-temperature ionic liquids based on the imidazolium, pyridinium, and phosphonium cations, namely 1-octyl-3-methylimidazolium hexafluorophosphate, N-octylpyridinium tetrafluorophosphate, trihexyl(tetradecyl)phosphonium chloride, trihexyl(tetradecyl)phosphonium bromide, trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)imide, and trihexyl(tetradecyl)phosphonium dicyanamide, were accurately measured. In this way, we extended our database of partition coefficients in room-temperature ionic liquids previously reported. We employed the solvation parameter model with different probe molecules (the training set) to elucidate the chemical interactions involved in the partition process and discussed the most relevant differences among the three types of ionic liquids. The multiparametric equations obtained with the aforementioned model were used to predict the partition coefficients for compounds (the test set) not present in the training set, most being of biological and pharmacological interest. An excellent agreement between calculated and experimental log P IL/w values was obtained. Thus, the obtained equations can be used to predict, a priori, the extraction efficiency for any compound using these ionic liquids as extraction solvents in liquid-liquid extractions.

Magnetical hollow fiber bar collection of extract in homogenous ionic liquid microextraction of triazine herbicides in water samples.

PubMed

Wang, Kun; Jiang, Jia; Kang, Mingqin; Li, Dan; Zang, Shuang; Tian, Sizhu; Zhang, Hanqi; Yu, Aimin; Zhang, Ziwei

2017-04-01

The homogeneous ionic liquid microextraction combined with magnetical hollow fiber bar collection was developed for extracting triazine herbicides from water samples. These analytes were separated and determined by high performance liquid chromatography. The triazines were quickly extracted into ionic liquid microdroplets dispersed in solution, and then these microdroplets were completely collected with magnetical hollow fiber bars; the pores of which were impregnated with hydrophobic ionic liquid, which makes the phase separation simplified with no need of centrifugation. Some experimental parameters, such as the type of ionic liquid, ultrasonic immersion time of hollow fiber, pH of sample solution, volume of hydrophilic ionic liquid, amount of ion-pairing agent NH 4 PF 6 , NaCl concentration, number of magnetical hollow fiber bar, stirring rate, and collection time were investigated and optimized. When the present method was applied to the analysis of real water samples, the precision and recoveries of six triazine herbicides vary from 0.1 to 9.2% and 73.4 to 118.5%, respectively. The detection limits for terbumeton, ametryn, prometryn, terbutryn, trietazine, and dimethametryn were 0.48, 0.15, 0.15, 0.14, 0.35, and 0.16 μg L -1 , respectively.

Simple high-performance liquid chromatography method for formaldehyde determination in human tissue through derivatization with 2,4-dinitrophenylhydrazine.

PubMed

Yilmaz, Bilal; Asci, Ali; Kucukoglu, Kaan; Albayrak, Mevlut

2016-08-01

A simple high-performance liquid chromatography method has been developed for the determination of formaldehyde in human tissue. FA Formaldehyde was derivatized with 2,4-dinitrophenylhydrazine. It was extracted from human tissue with ethyl acetate by liquid-liquid extraction and analyzed by high-performance liquid chromatography. The calibration curve was linear in the concentration range of 5.0-200 μg/mL. Intra- and interday precision values for formaldehyde in tissue were <6.9%, and accuracy (relative error) was better than 6.5%. The extraction recoveries of formaldehyde from human tissue were between 88 and 98%. The limits of detection and quantification of formaldehyde were 1.5 and 5.0 μg/mL, respectively. Also, this assay was applied to liver samples taken from a biopsy material. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of a new extraction method based on counter current salting-out homogenous liquid-liquid extraction followed by dispersive liquid-liquid microextraction: Application for the extraction and preconcentration of widely used pesticides from fruit juices.

PubMed

Farajzadeh, Mir Ali; Feriduni, Behruz; Mogaddam, Mohammad Reza Afshar

2016-01-01

In this paper, a new extraction method based on counter current salting-out homogenous liquid-liquid extraction (CCSHLLE) followed by dispersive liquid-liquid microextraction (DLLME) has been developed for the extraction and preconcentration of widely used pesticides in fruit juice samples prior to their analysis by gas chromatography-flame ionization detection (GC-FID). In this method, initially, sodium chloride as a separation reagent is filled into a small column and a mixture of water (or fruit juice) and acetonitrile is passed through the column. By passing the mixture sodium chloride is dissolved and the fine droplets of acetonitrile are formed due to salting-out effect. The produced droplets go up through the remained mixture and collect as a separated layer. Then, the collected organic phase (acetonitrile) is removed with a syringe and mixed with 1,1,2,2-tetrachloroethane (extraction solvent at µL level). In the second step, for further enrichment of the analytes the above mixture is injected into 5 mL de-ionized water placed in a test tube with conical bottom in order to dissolve acetonitrile into water and to achieve a sedimented phase at µL-level volume containing the enriched analytes. Under the optimal extraction conditions (extraction solvent, 1.5 mL acetonitrile; pH, 7; flow rate, 0.5 mL min(-1); preconcentration solvent, 20 µL 1,1,2,2-tetrachloroethane; NaCl concentration; 5%, w/w; and centrifugation rate and time, 5000 rpm and 5 min, respectively), the extraction recoveries and enrichment factors ranged from 87% to 96% and 544 to 600, respectively. Repeatability of the proposed method, expressed as relative standard deviations, ranged from 2% to 6% for intra-day (n=6, C=250 or 500 µg L(-1)) and inter-days (n=4, C=250 or 500 µg L(-1)) precisions. Limits of detection are obtained between 2 and 12 µg L(-1). Finally, the proposed method is applied for the determination of the target pesticide residues in the juice samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Analysis of Lard in Lipstick Formulation Using FTIR Spectroscopy and Multivariate Calibration: A Comparison of Three Extraction Methods.

PubMed

Waskitho, Dri; Lukitaningsih, Endang; Sudjadi; Rohman, Abdul

2016-01-01

Analysis of lard extracted from lipstick formulation containing castor oil has been performed using FTIR spectroscopic method combined with multivariate calibration. Three different extraction methods were compared, namely saponification method followed by liquid/liquid extraction with hexane/dichlorometane/ethanol/water, saponification method followed by liquid/liquid extraction with dichloromethane/ethanol/water, and Bligh & Dyer method using chloroform/methanol/water as extracting solvent. Qualitative and quantitative analysis of lard were performed using principle component (PCA) and partial least square (PLS) analysis, respectively. The results showed that, in all samples prepared by the three extraction methods, PCA was capable of identifying lard at wavelength region of 1200-800 cm -1 with the best result was obtained by Bligh & Dyer method. Furthermore, PLS analysis at the same wavelength region used for qualification showed that Bligh and Dyer was the most suitable extraction method with the highest determination coefficient (R 2 ) and the lowest root mean square error of calibration (RMSEC) as well as root mean square error of prediction (RMSEP) values.

Exploiting 1,2,3-Triazolium Ionic Liquids for Synthesis of Tryptanthrin and Chemoselective Extraction of Copper(II) Ions and Histidine-Containing Peptides.

PubMed

Li, Hsin-Yi; Chen, Chien-Yuan; Cheng, Hui-Ting; Chu, Yen-Ho

2016-10-13

Based on a common structural core of 4,5,6,7-tetrahydro[1,2,3]triazolo[1,5- a ]pyridine, a number of bicyclic triazolium ionic liquids 1 - 3 were designed and successfully prepared. In our hands, this optimized synthesis of ionic liquids 1 and 2 requires no chromatographic separation. Also in this work, ionic liquids 1 , 2 were shown to be efficient ionic solvents for fast synthesis of tryptanthrin natural product. Furthermore, a new affinity ionic liquid 3 was tailor-synthesized and displayed its effectiveness in chemoselective extraction of both Cu(II) ions and, for the first time, histidine-containing peptides.

Hollow fiber-based liquid-liquid-liquid micro-extraction with osmosis: II. Application to quantification of endogenous gibberellins in rice plant.

PubMed

Wu, Qian; Wu, Dapeng; Duan, Chunfeng; Shen, Zheng; Guan, Yafeng

2012-11-23

The phenomenon and benefits of osmosis in hollow fiber-based liquid-liquid-liquid micro-extraction (HF-LLLME) were theoretically discussed in part I of this study. In this work, HF-LLLME with osmosis was coupled with high performance liquid chromatography-triple quadrupole mass spectrometry (HPLC-triple quadrupole MS/MS) to analyze eight gibberellins (gibberellin A(1), gibberellin A(3), gibberellin A(4), gibberellin A(7), gibberellin A(8), gibberellin A(9), gibberellin A(19) and gibberellin A(20)) in rice plant samples. According to the theory of HF-LLLME with osmosis, single factor experiments, orthogonal design experiments and mass transfer simulation of extraction process were carried out to select the optimal conditions. Cyclohexanol - n-octanol (1:3, v/v) was selected as organic membrane. Donor phase of 12 mL was adjusted to pH 2 and 20% NaCl (w/v) was added. Acceptor phase with an initial volume of 20 μL was the solution of 0.12 mol L(-1) Na(2)CO(3)-NaHCO(3) buffer (pH 9). Temperature was chosen to be 30 °C and extraction time was selected to be 90 min. Under optimized conditions, this method provided good linearity (r, 0.99552-0.99991) and low limits of detection (0.0016-0.061 ng mL(-1)). Finally, this method was applied to the analysis of endogenous gibberellins from plant extract which was obtained with traditional solvent extraction of rice plant tissues, and the relative recoveries were from 62% to 166%. Copyright © 2012 Elsevier B.V. All rights reserved.

A novel high-throughput method for supported liquid extraction of retinol and alpha-tocopherol from human serum and simultaneous quantitation by liquid chromatography tandem mass spectrometry.

PubMed

Hinchliffe, Edward; Rudge, James; Reed, Paul

2016-07-01

Measurement of vitamin A (retinol) and E (alpha-tocopherol) in UK clinical laboratories is currently performed exclusively by high-performance liquid chromatography with ultraviolet detection. We investigated whether retinol and alpha-tocopherol could be measured simultaneously by liquid chromatography tandem mass spectrometry. Serum samples (100 μL) were extracted using Isolute + Supported Liquid Extraction plates. Chromatography was performed on a Phenomenex Kinetex Biphenyl 2.6 μm, 50 × 2.1 mm column, and liquid chromatography tandem mass spectrometry on a Waters Acquity TQD. Injection-to-injection time was 4.3 min. The assay was validated according to published guidelines. Patient samples were used to compare liquid chromatography tandem mass spectrometry and high-performance liquid chromatography with ultraviolet detection methods. For retinol and alpha-tocopherol, respectively, the assay was linear up to 6.0 and 80.0 μmol/L, and lower limit of quantification was 0.07 and 0.26 μmol/L. Intra and interassay imprecision were within desirable analytical specifications. Analysis of quality control material aligned to NIST SRM 968e, and relative spiked recovery from human serum, both yielded results within 15% of target values. Method comparison with high-performance liquid chromatography with ultraviolet detection methodology demonstrated a negative bias for retinol and alpha-tocopherol by the liquid chromatography tandem mass spectrometry method. Analysis of United Kingdom National External Quality Assurance Scheme samples yielded mean bias from the target value of +3.0% for retinol and -11.2% for alpha-tocopherol. We have developed a novel, high-throughput method for extraction of retinol and alpha-tocopherol from human serum followed by simultaneous quantitation by liquid chromatography tandem mass spectrometry. The method offers a rapid, sensitive, specific and cost-effective alternative to high-performance liquid chromatography with ultraviolet detection methodology, and is suitable for routine clinical monitoring of patients predisposed to fat-soluble vitamin malabsorption. © The Author(s) 2015.

Estimated content percentages of volatile liquids and fat extractables in ready-to-eat foods.

PubMed

Daft, J L; Cline, J K; Palmer, R E; Sisk, R L; Griffitt, K R

1996-01-01

Content percentages of volatile liquids and fat extractables in 340 samples of ready-to-eat foods were determined gravimetrically. Volatile liquids were determined by drying samples in a microwave oven with a self-contained balance; results were printed out automatically. Fat extractables were extracted from the samples with mixed ethers; extracts were dried and weighed manually. The samples, 191 nonfat and 149 fatty (containing ca 2% or more fat) foods, represent about 5000 different food items and include infant and toddler, ethnic, fast, and imported items. Samples were initially prepared for screening of essential and toxic elements and chemical contamination by chopping and mixing into homogenous composites. Content determinations were then made on separate portions from each composite. Content results were put into a database for evaluation. Overall, mean results from both determinations agree with published data for moisture and fat contents of similar food items. Coefficients of variation, however, were lower for determination of volatile liquids than for that of fat extractables.

Determination of volatile components of green, black, oolong and white tea by optimized ultrasound-assisted extraction-dispersive liquid-liquid microextraction coupled with gas chromatography.

PubMed

Sereshti, Hassan; Samadi, Soheila; Jalali-Heravi, Mehdi

2013-03-08

Ultrasound assisted extraction (UAE) followed by dispersive liquid-liquid microextraction (DLLME) was used for extraction and preconcentration of volatile constituents of six tea plants. The preconcentrated compounds were analyzed by gas chromatography-mass spectrometry (GC-MS). Totally, 42 compounds were identified and caffeine was quantitatively determined. The main parameters (factors) of the extraction process were optimized by using a central composite design (CCD). Methanol and chloroform were selected as the extraction solvent and preconcentration solvent, respectively .The optimal conditions were obtained as 21 in for sonication time; 32°C for temperature; 27 L for volume of extraction solvent and 7.4% for salt concentration (NaCl/H(2)O). The determination coefficient (R(2)) was 0.9988. The relative standard deviation (RSD %) was 4.8 (n=5), and the enhancement factors (EFs) were 4.0-42.6. Copyright © 2013 Elsevier B.V. All rights reserved.

A generalized theory of chromatography and multistep liquid extraction

NASA Astrophysics Data System (ADS)

Chizhkov, V. P.; Boitsov, V. N.

2017-03-01

A generalized theory of chromatography and multistep liquid extraction is developed. The principles of highly efficient processes for fine preparative separation of binary mixture components on a fixed sorbent layer are discussed.

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

PubMed

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.

Speciation of organotin compounds in urine by GC-MIP-AED and GC-MS after ethylation and liquid-liquid extraction.

PubMed

Zachariadis, G A; Rosenberg, E

2009-04-15

A method for the determination of organotin compounds in urine samples based on liquid-liquid extraction (LLE) in hexane and gas chromatographic separation was developed and optimized. Seven organotin species, namely monobutyltin (MBT), dibutyltin (DBT), tributyltin (TBT), tetrabutyltin (TeBT), monophenyltin (MPhT), diphenyltin (DPhT) and triphenyltin (TPhT), were in situ derivatized by sodium tetraethylborate (NaBEt(4)) to form ethylated less polar derivatives directly in the urine matrix. The critical parameters which have a significant effect on the yield of the successive liquid-liquid extraction procedure were examined, by using standard solutions of tetrabutyltin in hexane. The method was optimized for use in direct analysis of undiluted human urine samples and ways to overcome practical problems such as foam formation during extraction, due to various constituents of urine are discussed. After thorough optimization of the extraction procedure, all examined species could be determined after 3 min of simultaneous derivatization and extraction at room temperature and 5 min phase separation by centrifugation. Gas chromatography with a microwave-induced plasma atomic emission detector (MIP-AED) as element specific detector was employed for quantitative measurements, while a quadrupole mass spectrometric detector (MS) was used as molecular specific detector. The detection limits were between 0.42 and 0.67 microg L(-1) (as Sn) for the quantitative LLE-GC-MIP-AED method and the precision between 4.2% and 11.7%, respectively.

Analytical methods for the assessment of endocrine disrupting chemical exposure during human fetal and lactation stages: a review.

PubMed

Jiménez-Díaz, I; Vela-Soria, F; Rodríguez-Gómez, R; Zafra-Gómez, A; Ballesteros, O; Navalón, A

2015-09-10

In the present work, a review of the analytical methods developed in the last 15 years for the determination of endocrine disrupting chemicals (EDCs) in human samples related with children, including placenta, cord blood, amniotic fluid, maternal blood, maternal urine and breast milk, is proposed. Children are highly vulnerable to toxic chemicals in the environment. Among these environmental contaminants to which children are at risk of exposure are EDCs -substances able to alter the normal hormone function of wildlife and humans-. The work focuses mainly on sample preparation and instrumental techniques used for the detection and quantification of the analytes. The sample preparation techniques include, not only liquid-liquid extraction (LLE) and solid-phase extraction (SPE), but also modern microextraction techniques such as extraction with molecular imprinted polymers (MIPs), stir-bar sorptive extraction (SBSE), hollow-fiber liquid-phase microextraction (HF-LPME), dispersive liquid-liquid microextraction (DLLME), matrix solid phase dispersion (MSPD) or ultrasound-assisted extraction (UAE), which are becoming alternatives in the analysis of human samples. Most studies focus on minimizing the number of steps and using the lowest solvent amounts in the sample treatment. The usual instrumental techniques employed include liquid chromatography (LC), gas chromatography (GC) mainly coupled to tandem mass spectrometry. Multiresidue methods are being developed for the determination of several families of EDCs with one extraction step and limited sample preparation. Copyright © 2015 Elsevier B.V. All rights reserved.

Automated dynamic hollow fiber liquid-liquid-liquid microextraction combined with capillary electrophoresis for speciation of mercury in biological and environmental samples.

PubMed

Li, Pingjing; He, Man; Chen, Beibei; Hu, Bin

2015-10-09

A simple home-made automatic dynamic hollow fiber based liquid-liquid-liquid microextraction (AD-HF-LLLME) device was designed and constructed for the simultaneous extraction of organomercury and inorganic mercury species with the assistant of a programmable flow injection analyzer. With 18-crown-6 as the complexing reagent, mercury species including methyl-, ethyl-, phenyl- and inorganic mercury were extracted into the organic phase (chlorobenzene), and then back-extracted into the acceptor phase of 0.1% (m/v) 3-mercapto-1-propanesulfonic acid (MPS) aqueous solution. Compared with automatic static (AS)-HF-LLLME system, the extraction equilibrium of target mercury species was obtained in shorter time with higher extraction efficiency in AD-HF-LLLME system. Based on it, a new method of AD-HF-LLLME coupled with large volume sample stacking (LVSS)-capillary electrophoresis (CE)/UV detection was developed for the simultaneous analysis of methyl-, phenyl- and inorganic mercury species in biological samples and environmental water. Under the optimized conditions, AD-HF-LLLME provided high enrichment factors (EFs) of 149-253-fold within relatively short extraction equilibrium time (25min) and good precision with RSD between 3.8 and 8.1%. By combining AD-HF-LLLME with LVSS-CE/UV, EFs were magnified up to 2195-fold and the limits of detection (at S/N=3) for target mercury species were improved to be sub ppb level. Copyright © 2015 Elsevier B.V. All rights reserved.

Rapid screening of oxytetracycline residue in catfish muscle by dispersive liquid-liquid microextraction and europium-sensitized luminescence

USDA-ARS?s Scientific Manuscript database

Oxytetracycline (OTC) residue in catfish muscle was screened by dispersive liquid-liquid microextraction (DLLME) and europium-sensitized luminescence (ESL). After extraction in EDTA, HCl, and acetonitrile, cleanup was carried out by DLLME, and ESL was measured at microgram = 385 nm and wavelength = ...

Isolation of Xanthomegnin from Penicillium viridicatum by Preparative High-Pressure Liquid Chromatography

PubMed Central

Peterson, R. E.; Grove, M. D.

1983-01-01

A method was developed for the production and purification of xanthomegnin from Penicillium viridicatum (NRRL 6430) cultured on rice at 15°C for 29 days. Liquid-liquid extraction followed by high-pressure liquid chromatography afforded 440 mg of crystalline xanthomegnin per kg of rice. PMID:6881966

Luminescence screening of enrofloxacin and ciprofloxacin residues in swine liver after dispersive liquid - liquid microextraction cleanup

USDA-ARS?s Scientific Manuscript database

A rapid luminescence method was developed to screen residues of enrofloxacin (ENRO) and its metabolite, ciprofloxacin (CIPRO), in swine liver. Target analytes were extracted in acetonitrile-2.5% trifluoroacetic acid-NaCl, cleaned up by dispersive liquid-liquid microextraction (DLLME), and finally de...

Sample processor for the automatic extraction of families of compounds from liquid samples and/or homogenized solid samples suspended in a liquid

NASA Technical Reports Server (NTRS)

Jahnsen, Vilhelm J. (Inventor); Campen, Jr., Charles F. (Inventor)

1980-01-01

A sample processor and method for the automatic extraction of families of compounds, known as extracts, from liquid and/or homogenized solid samples are disclosed. The sample processor includes a tube support structure which supports a plurality of extraction tubes, each containing a sample from which families of compounds are to be extracted. The support structure is moveable automatically with respect to one or more extraction stations, so that as each tube is at each station a solvent system, consisting of a solvent and reagents, is introduced therein. As a result an extract is automatically extracted from the tube. The sample processor includes an arrangement for directing the different extracts from each tube to different containers, or to direct similar extracts from different tubes to the same utilization device.

Study of axial mixing, holdup and slip velocity of dispersed phase in a pulsed sieve plate extraction column using radiotracer technique.

PubMed

Ghiyas Ud Din; Imran Rafiq Chughtai; Hameed Inayat, Mansoor; Hussain Khan, Iqbal

2009-01-01

Axial mixing, holdup and slip velocity of dispersed phase which are parameters of fundamental importance in the design and operation of liquid-liquid extraction pulsed sieve plate columns have been investigated. Experiments for residence time distribution (RTD) analysis have been carried out for a range of pulsation frequency and amplitude in a liquid-liquid extraction pulsed sieve plate column with water as dispersed and kerosene as continuous phase using radiotracer technique. The column was operated in emulsion region and (99m)Tc in the form of sodium pertechnetate eluted from a (99)Mo/(99m)Tc generator was used to trace the dispersed phase. Axial dispersed plug flow model with open-open boundary condition and two points measurement method was used to simulate the hydrodynamics of dispersed phase. It has been observed that the axial mixing and holdup of dispersed phase increases with increase in pulsation frequency and amplitude until a maximum value is achieved while slip velocity decreases with increase in pulsation frequency and amplitude until it approaches a minimum value. Short lived and low energy radiotracer (99m)Tc in the form of sodium pertechnetate was found to be a good water tracer to study the hydrodynamics of a liquid-liquid extraction pulsed sieve plate column operating with two immiscible liquids, water and kerosene. Axial dispersed plug flow model with open-open boundary condition was found to be a suitable model to describe the hydrodynamics of dispersed phase in the pulsed sieve plate extraction column.

Recovery of Scandium from Leachate of Sulfation-Roasted Bayer Red Mud by Liquid-Liquid Extraction

NASA Astrophysics Data System (ADS)

Liu, Zhaobo; Li, Hongxu; Jing, Qiankun; Zhang, Mingming

2017-11-01

The leachate obtained from sulfation-roasted Bayer red mud is suitable for extraction of scandium by liquid-liquid solvent extraction because it contains trace amounts of Fe3+ and Si4+. In this study, a completely new metallurgical process for selective recovery of scandium from Bayer red mud was proposed. The extraction performances of Sc3+, Fe3+, Al3+, Si4+, Ca2+, and Na+ from synthetic leachate of sulfation-roasted red mud were first investigated using organophosphorus extractants (di-2-ethylhexyl phosphoric acid P204 and 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester P507) and carboxylic acid extractant (Versatic acid 10). It shows that P204 has an excellent extraction ability and that it can be applied to the scandium recovery. P507 and Versatic acid 10 are much poorer in performance for selective extraction of scandium. In the leachate of sulfation-roasted red mud, approximately 97% scandium can be recovered using a P204/sulfonated kerosene (1% v/v) extraction system under the condition of an organic-to-aqueous phase ratio of 10:1 and with an extraction temperature of 15°C.

Chiral nematic porous germania and germanium/carbon films

NASA Astrophysics Data System (ADS)

Xu, Jing; Nguyen, Thanh-Dinh; Xie, Kai; Hamad, Wadood Y.; MacLachlan, Mark J.

2015-07-01

We report our extensive attempts and, ultimately, success to produce crack-free, chiral nematic GeO2/cellulose nanocrystal (CNC) composite films with tunable photonic properties from the controlled assembly of germanium(iv) alkoxides with the lyotropic liquid-crystalline CNCs in a mixed solvent of water/DMF. With different pyrolysis conditions, the photonic GeO2/CNC composites can be converted into freestanding chiral nematic films of amorphous GeO2, and semiconducting mesoporous GeO2/C and Ge/C replicas. These new materials are promising for chiral separation, enantioselective adsorption, catalysis, sensing, optoelectronics, and lithium ion batteries. Furthermore, the new, reproducible synthesis strategies developed may be applicable for constructing other composites and porous materials with chiral nematic ordering.We report our extensive attempts and, ultimately, success to produce crack-free, chiral nematic GeO2/cellulose nanocrystal (CNC) composite films with tunable photonic properties from the controlled assembly of germanium(iv) alkoxides with the lyotropic liquid-crystalline CNCs in a mixed solvent of water/DMF. With different pyrolysis conditions, the photonic GeO2/CNC composites can be converted into freestanding chiral nematic films of amorphous GeO2, and semiconducting mesoporous GeO2/C and Ge/C replicas. These new materials are promising for chiral separation, enantioselective adsorption, catalysis, sensing, optoelectronics, and lithium ion batteries. Furthermore, the new, reproducible synthesis strategies developed may be applicable for constructing other composites and porous materials with chiral nematic ordering. Electronic supplementary information (ESI) available: TGA, IR, Raman, TEM, SEM, BET. See DOI: 10.1039/c5nr02520f

Determination of capsaicinoids in topical cream by liquid-liquid extraction and liquid chromatography.

PubMed

Kaale, Eliangiringa; Van Schepdael, Ann; Roets, Eugène; Hoogmartens, Jos

2002-11-07

A reversed-phase liquid chromatography (LC) method has been developed, optimised and validated for the separation and quantitation of capsaicin (CP) and dihydrocapsaicin (DHCP) in a topical cream formulation. Sample preparation involves liquid-liquid extraction prior to LC analysis. The method uses a Hypersil C(18) BDS, 5 micrometer, 250x4.6 mm I.D. column maintained at 35 degrees C. The mobile phase comprises methanol, water, acetonitrile (ACN) and acetic acid (47:42:10:1, v/v/v/v) at a flow rate of 1.0 ml/min. Robustness was evaluated by performing a central composite face-centred design (CCF) experiment. The method shows good selectivity, linearity, sensitivity and repeatability. The conditions allow the separation and quantitation of CP and DHCP without interference from the other substances contained in the cream.

Magnetic ionic liquid-based dispersive liquid-liquid microextraction technique for preconcentration and ultra-trace determination of Cd in honey.

PubMed

Fiorentini, Emiliano F; Escudero, Leticia B; Wuilloud, Rodolfo G

2018-04-19

A simple, highly efficient, batch, and centrifuge-less dispersive liquid-liquid microextraction method based on a magnetic ionic liquid (MIL-DLLME) and electrothermal atomic absorption spectrometry (ETAAS) detection was developed for ultra-trace Cd determination in honey. Initially, Cd(II) was chelated with ammonium diethyldithiophosphate (DDTP) at pH 0.5 followed by its extraction with the MIL trihexyl(tetradecyl)phosphonium tetrachloroferrate(III) ([P 6,6,6,14 ]FeCl 4 ) and acetonitrile as dispersant. The MIL phase containing the analyte was separated from the aqueous phase using only a magnet. A back-extraction procedure was applied to recover Cd from the MIL phase using diluted HNO 3 and this solution was directly injected into the graphite furnace of ETAAS instrument. An extraction efficiency of 93% and a sensitivity enhancement factor of 112 were obtained under optimal experimental conditions. The detection limit (LOD) was 0.4 ng L -1 Cd, while the relative standard deviation (RSD) was 3.8% (at 2 μg L -1 Cd and n = 10), calculated from the peak height of absorbance signals. This work reports the first application of the MIL [P 6,6,6,14 ]FeCl 4 along with the DLLME technique for the successful determination of Cd at trace levels in different honey samples. Graphical abstract Preconcentration of ultratraces of Cd in honey using a magnetic ionic liquid and dispersive liquid-liquid microextraction technique.

Inhibitory activity of a standardized elderberry liquid extract against clinically-relevant human respiratory bacterial pathogens and influenza A and B viruses

PubMed Central

2011-01-01

Background Black elderberries (Sambucus nigra L.) are well known as supportive agents against common cold and influenza. It is further known that bacterial super-infection during an influenza virus (IV) infection can lead to severe pneumonia. We have analyzed a standardized elderberry extract (Rubini, BerryPharma AG) for its antimicrobial and antiviral activity using the microtitre broth micro-dilution assay against three Gram-positive bacteria and one Gram-negative bacteria responsible for infections of the upper respiratory tract, as well as cell culture experiments for two different strains of influenza virus. Methods The antimicrobial activity of the elderberry extract was determined by bacterial growth experiments in liquid cultures using the extract at concentrations of 5%, 10%, 15% and 20%. The inhibitory effects were determined by plating the bacteria on agar plates. In addition, the inhibitory potential of the extract on the propagation of human pathogenic H5N1-type influenza A virus isolated from a patient and an influenza B virus strain was investigated using MTT and focus assays. Results For the first time, it was shown that a standardized elderberry liquid extract possesses antimicrobial activity against both Gram-positive bacteria of Streptococcus pyogenes and group C and G Streptococci, and the Gram-negative bacterium Branhamella catarrhalis in liquid cultures. The liquid extract also displays an inhibitory effect on the propagation of human pathogenic influenza viruses. Conclusion Rubini elderberry liquid extract is active against human pathogenic bacteria as well as influenza viruses. The activities shown suggest that additional and alternative approaches to combat infections might be provided by this natural product. PMID:21352539

Supported liquid inorganic membranes for nuclear waste separation

DOEpatents

Bhave, Ramesh R; DeBusk, Melanie M; DelCul, Guillermo D; Delmau, Laetitia H; Narula, Chaitanya K

2015-04-07

A system and method for the extraction of americium from radioactive waste solutions. The method includes the transfer of highly oxidized americium from an acidic aqueous feed solution through an immobilized liquid membrane to an organic receiving solvent, for example tributyl phosphate. The immobilized liquid membrane includes porous support and separating layers loaded with tributyl phosphate. The extracted solution is subsequently stripped of americium and recycled at the immobilized liquid membrane as neat tributyl phosphate for the continuous extraction of americium. The sequestered americium can be used as a nuclear fuel, a nuclear fuel component or a radiation source, and the remaining constituent elements in the aqueous feed solution can be stored in glassified waste forms substantially free of americium.

Optimization of Pressurized Liquid Extraction of Three Major Acetophenones from Cynanchum bungei Using a Box-Behnken Design

PubMed Central

Li, Wei; Zhao, Li-Chun; Sun, Yin-Shi; Lei, Feng-Jie; Wang, Zi; Gui, Xiong-Bin; Wang, Hui

2012-01-01

In this work, pressurized liquid extraction (PLE) of three acetophenones (4-hydroxyacetophenone, baishouwubenzophenone, and 2,4-dihydroxyacetophenone) from Cynanchum bungei (ACB) were investigated. The optimal conditions for extraction of ACB were obtained using a Box-Behnken design, consisting of 17 experimental points, as follows: Ethanol (100%) as the extraction solvent at a temperature of 120 °C and an extraction pressure of 1500 psi, using one extraction cycle with a static extraction time of 17 min. The extracted samples were analyzed by high-performance liquid chromatography using an UV detector. Under this optimal condition, the experimental values agreed with the predicted values by analysis of variance. The ACB extraction yield with optimal PLE was higher than that obtained by soxhlet extraction and heat-reflux extraction methods. The results suggest that the PLE method provides a good alternative for acetophenone extraction. PMID:23203079

An automated system for liquid-liquid extraction in monosegmented flow analysis

PubMed Central

Facchin, Ileana; Pasquini, Celio

1997-01-01

An automated system to perform liquid-liquid extraction in monosegmented flow analysis is described. The system is controlled by a microcomputer that can track the localization of the aqueous monosegmented sample in the manifold. Optical switches are employed to sense the gas-liquid interface of the air bubbles that define the monosegment. The logical level changes, generated by the switches, are flagged by the computer through a home-made interface that also contains the analogue-to-digital converter for signal acquisition. The sequence of operations, necessary for a single extraction or for concentration of the analyte in the organic phase, is triggered by these logical transitions. The system was evaluated for extraction of Cd(II), Cu(II) and Zn(II) and concentration of Cd(II) from aqueous solutions at pH 9.9 (NH3/NH4Cl buffer) into chloroform containing PAN (1-(2-pyridylazo)-2-naphthol) . The results show a mean repeatability of 3% (rsd) for a 2.0 mg l-1 Cd(II) solution and a linear increase of the concentration factor for a 0.5mg l-1 Cd(II) solution observed for up to nine extraction cycles. PMID:18924792

A simple, rapid and novel method based on salting-out assisted liquid-liquid extraction for ochratoxin A determination in beer samples prior to ultra-high performance liquid chromatography coupled to tandem mass spectrometry.

PubMed

Mariño-Repizo, Leonardo; Goicoechea, Hector; Raba, Julio; Cerutti, Soledad

2018-06-07

A novel, simple, easy and cheap sample treatment strategy based on salting-out assisted liquid-liquid extraction (SALLE) for ochratoxin A (OTA) ultra-trace analysis in beer samples using ultra-high performance liquid chromatography-tandem mass spectrometry determination was developed. The factors involved in the efficiency of pretreatment were studied employing factorial design in the screening phase and the optimal conditions of the significant variables on the analytical response were evaluated using a central composite face-centred design (CCF). Consequently, the amount of salt ((NH 4 ) 2 SO 4 ), together with the volumes of sample, hydrophilic (acetone) and nonpolar (toluene) solvents, and times of vortexing and centrifugation were optimized. Under optimized conditions, the limits of detection (LOD) and quantification (LOQ) were 0.02 µg l -1 and 0.08 µg l -1 respectively. OTA extraction recovery by SALLE was approximately 90% (0.2 µg l -1 ). Furthermore, the methodology was in agreement with EU Directive requirements and was successfully applied for analysis of beer samples.

Liquid to liquid extraction and liquid chromatography-tandem mass spectrometry determination of hainanmycin in feed.

PubMed

Wang, Ze Ping; Shen, Jian Zhong; Linhardt, Robert J; Jiang, Hui; Cheng, Lin Li

2017-03-01

Hainanmycin is a new veterinary polyether antibiotic and has few sensitive analytical method in present days. In this study, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) relying on multiple reaction monitoring (MRM) detection was developed for analysis of hainanmycin in animal feed. Feed samples were extracted with ethyl acetate and purified by two steps of liquid-liquid extraction (LLE) to get rid of water solvable matrix and lipids one by one. The final simple was analyzed by LC-MS/MS. The LC mobile phase was composed of 0.1% aqueous formic acid and 0.1% formic acidified acetonitrile by gradient elution. Average recoveries ranged from 74.22% to 87.85%, as determined by spiking with 2.0 (LOQ) ∼2500μgkg -1 of hainanmycin. The inter-day and intra-day coefficient of variation was 9.21% to 11.77% and 7.67% to 13.49%, respectively. The limit of detection (LOD) and the limit of quantitation (LOQ) were 0.36μgkg -1 and 2.0μgkg -1 , respectively. Copyright © 2016. Published by Elsevier B.V.

Liquid Microjunction Surface Sampling Coupled with High-Pressure Liquid Chromatography-Electrospray Ionization-Mass Spectrometry for Analysis of Drugs and Metabolites in Whole-Body Thin Tissue Sections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kertesz, Vilmos; Van Berkel, Gary J

2010-01-01

In this work, a commercially available autosampler was adapted to perform direct liquid microjunction (LMJ) surface sampling followed by a high-pressure liquid chromatography (HPLC) separation of the extract components and detection with electrospray ionization mass spectrometry (ESI-MS). To illustrate the utility of coupling a separation with this direct liquid extraction based surface sampling approach, four different organs (brain, lung, kidney, and liver) from whole-body thin tissue sections of propranolol dosed and control mice were examined. The parent drug was observed in the chromatograms of the surface sampling extracts from all the organs of the dosed mouse examined. In addition, twomore » isomeric phase II metabolites of propranolol (an aliphatic and an aromatic hydroxypropranolol glucuronide) were observed in the chromatograms of the extracts from lung, kidney, and liver. Confirming the presence of one or the other or both of these glucuronides in the extract from the various organs was not possible without the separation. These drug and metabolite data obtained using the LMJ surface sampling/HPLC-MS method and the results achieved by analyzing similar samples by conventional extraction of the tissues and subsequent HPLC-MS analysis were consistent.« less

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

PubMed

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.

Comparison of a Lyophilized Drug Product to Other Solid and Liquid Media for the Extraction of Elastomeric Oligomers from a Butyl Rubber Stopper.

PubMed

Zdravkovic, Steven A

2017-01-01

Lyophilization is commonly used to extend the shelf life of pharmaceutical products that are otherwise unstable when stored as a liquid formulation. However, the ability of a lyophilized drug, or other solid medium, to leach or extract substances from a pharmaceutical packaging material is not well characterized. To provide insight into this area of uncertainty, the extraction properties of a lyophilized drug product, the lyophilized drug product reconstituted in water, and several other solid and liquid media of varying polarity were determined using a glass vial with a butyl rubber stopper as a representative pharmaceutical packaging system. The results obtained in this study show that the extracting power of a medium, whether solid or liquid, was primarily a function of polarity. Thus, the amount of each extractable observed for the lyophilized and reconstituted drug product were in trend with the other solid and liquid media, respectively. Nevertheless, it was notable that the lyophilized drug product was able to leach substances from the stopper in quantifiable amounts, whereas the reconstituted drug product contained no detectable leachables. Using a mathematical relationship, it was determined that the extraction power of the lyophilized drug product was equivalent to a 50/50 isopropanol/water solution. LAY ABSTRACT: Freeze drying is commonly used to extend the shelf life of pharmaceutical products that are otherwise unstable when stored as a liquid formulation. However, the propensity for substances to migrate from a pharmaceutical packaging material and into a solid drug formulation is not well characterized. To provide insight into this area of uncertainty, the migration of substances from a glass vial with a butyl rubber stopper and into a lyophilized drug product, the drug product reconstituted with water, as well as several solid and liquid media of varying polarity were assessed. The results obtained in this study show that the extracting power of a medium, whether solid or liquid, was primarily a function of polarity and thus could be related to one another. Furthermore, the results for the freeze-dried and reconstituted drug products were in trend with the other solid and liquid media tested, respectively, and showed that the freeze-dried drug was able to leach substances from the stopper in measureable amounts, whereas the reconstituted drug product contained no substances that had originated from the stopper. © PDA, Inc. 2017.

Novel 1,3-dioxanes from apple juice and cider.

PubMed

Kavvadias, D; Beuerle, T; Wein, M; Boss, B; König, T; Schwab, W

1999-12-01

Extracts obtained by XAD solid-phase extraction of apple juice and cider were separated by liquid chromatography on silica gel. Several new 1,3-dioxanes including the known 2-methyl-4-pentyl-1,3-dioxane and 2-methyl-4-[2'(Z)-pentenyl]-1,3-dioxane, were identified in the nonpolar fractions by GC/MS analysis and confirmed by chemical synthesis. The enantioselective synthesis of the stereoisomers of the 1,3-dioxanes was performed using (R)- and (R,S)-octane-1,3-diol and (R)- and (R,S)-5(Z)-octene-1,3-diol as starting material. Comparison with the isolated products indicated that the natural products consisted of a mixture of (2S,4R) and (2R,4R) stereoisomers in the ratio of approximately 10:1, except for 1,3-dioxanes generated from acetone and 2-butanone. It is assumed that the 1, 3-dioxanes are chemically formed in the apples and cider from the natural apple ingredients (R)-octane-1,3-diol, (R)-5(Z)-octene-1, 3-diol, (3R,7R)- and (3R,7S)-octane-1,3,7-triol, and the appropriate aldehydes and ketones, which are produced either by the apples or by yeast during fermentation of the apple juice.

Application of ionic liquids in vacuum microwave-assisted extraction followed by macroporous resin isolation of three flavonoids rutin, hyperoside and hesperidin from Sorbus tianschanica leaves.

PubMed

Gu, Huiyan; Chen, Fengli; Zhang, Qiang; Zang, Jing

2016-03-01

Rutin, hyperoside and hesperidin were effectively extracted from Sorbus tianschanica leaves by an ionic liquid vacuum microwave-assisted method. A series of ionic liquids with various anions and alkyl chain length of the cations were studied and the extraction was performed in [C6mim][BF4] aqueous solution. After optimization by a factorial design and response surface methodology, total extraction yield of 2.37mg/g with an error of 0.12mg/g (0.71±0.04mg/g, 1.18±0.06mg/g and 0.48±0.02 for rutin, hyperoside and hesperidin, respectively) was achieved under -0.08MPa for vacuum, 19min and 420W for microwave irradiation time and power, and 15mL/g for liquid-solid ratio. The proposed method here is more efficient and needs a shorter extraction time for rutin, hyperoside and hesperidin from S. tianschanica leaves than reference extraction techniques. In stability studies performed with standard rutin, hyperoside and hesperidin, the target analytes were stable under the optimum conditions. The proposed method had a high reproducibility and precision. In addition, separation of rutin, hyperoside and hesperidin from [C6mim][BF4] extraction solution was completed effectively by AB-8 macroporous resin adsorption and desorption process. Ionic liquid vacuum microwave-assisted extraction is a simple, rapid and efficient sample extraction technique. Copyright © 2016 Elsevier B.V. All rights reserved.

Isolation and characterization of antimicrobial food components.

PubMed

Papetti, Adele

2012-04-01

Nowadays there is an evident growing interest in natural antimicrobial compounds isolated from food matrices. According to the type of matrix, different isolation and purification steps are needed and as these active compounds belong to different chemical classes, also different chromatographic and electrophoretic methods coupled with various detectors (the most used diode array detector and mass spectrometer) have to be performed. This review covers recent steps made in the fundamental understanding of sample preparation methods as well as of analytical tools useful for the complete characterization of bioactive food compounds. The most commonly used methods for extraction of natural antimicrobial compounds are the conventional liquid-liquid or solid-liquid extraction and the modern techniques such as pressurized liquid extraction, microwave-assisted extraction, ultrasound-assisted extraction, solid-phase micro-extraction, supercritical fluid extraction, and matrix solid phase dispersion. The complete characterization of the compounds is achieved using both monodimensional chromatographic processes (LC, nano-LC, GC, and CE coupled with different type of detectors) and, recently, using comprehensive two-dimensional systems (LC×LC and GC×GC). Copyright © 2011 Elsevier Ltd. All rights reserved.

Ionic Liquid Dispersive Liquid-Liquid Microextraction Method for the Determination of Irinotecan, an Anticancer Drug, in Water and Urine Samples Using UV-Vis Spectrophotometry.

PubMed

Uysal, Deniz; Karadaş, Cennet; Kara, Derya

2017-05-01

A new, simple, efficient, and environmentally friendly ionic liquid dispersive liquid-liquid microextraction method was developed for the determination of irinotecan, an anticancer drug, in water and urine samples using UV-Vis spectrophotometry. The ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate was used as the extraction solvent, and ethanol was used as the disperser solvent. The main parameters affecting the extraction efficiency, including sample pH, volume of the ionic liquid, choice of the dispersive solvent and its volume, concentration of NaCl, and extraction and centrifugation times, were investigated and optimized. The effect of interfering species on the recovery of irinotecan was also examined. Under optimal conditions, the LOD (3σ) was 48.7 μg/L without any preconcentration. Because the urine sample was diluted 10-fold, the LOD for urine would be 487 μg/L. However, this could be improved 16-fold if preconcentration using a 40 mL aliquot of the sample is used. The proposed method was successfully applied to the determination of irinotecan in tap water, river water, and urine samples spiked with 10.20 mg/L for the water samples and 8.32 mg/L for the urine sample. The average recovery values of irinotecan determined were 99.1% for tap water, 109.4% for river water, and 96.1% for urine.

Capillary liquid chromatography combined with pressurized liquid extraction and dispersive liquid-liquid microextraction for the determination of vitamin E in cosmetic products.

PubMed

Viñas, Pilar; Pastor-Belda, Marta; Campillo, Natalia; Bravo-Bravo, María; Hernández-Córdoba, Manuel

2014-06-01

Capillary liquid chromatography (LC) is used for the determination of tocopherols and tocotrienols in cosmetic products. Dispersive liquid-liquid microextraction (DLLME) allows the analytes to be preconcentrated into a very small volume of organic solvent which is then injected into the chromatograph running at a very low flow rate. Pressurized liquid extraction (PLE) at a high temperature and pressure was used to isolate vitamin E forms from cosmetics. The Taguchi experimental method was used to optimize the factors affecting DLLME. The parameters selected were 2mL of acetonitrile (disperser solvent), 100μL carbon tetrachloride (extraction solvent) and 10mL aqueous solution. A volume of 5μL of the organic phase was injected into the reversed-phase capillary LC system equipped with a diode array detector and using an isocratic mobile phase composed of an 95:5 (v/v) methanol:water mixture at a flow-rate of 20μLmin(-1). Quantification was carried out using aqueous standards and detection limits were in the range 0.1-0.5ngmL(-1), corresponding to 3-15ngg(-1) in the cosmetic sample. The recoveries were in the 87-105% range, with RSDs lower than 7.8%. The method was validated according to international guidelines and using a certified reference material. Copyright © 2014 Elsevier B.V. All rights reserved.

Theoretical investigation of the interaction between aromatic sulfur compounds and [BMIM](+)[FeCl4](-) ionic liquid in desulfurization: A novel charge transfer mechanism.

PubMed

Li, Hongping; Zhu, Wenshuai; Chang, Yonghui; Jiang, Wei; Zhang, Ming; Yin, Sheng; Xia, Jiexiang; Li, Huaming

2015-06-01

In this work, interaction nature between a group of aromatic sulfur compounds and [BMIM](+)[FeCl4](-) have been investigated by density functional theory (DFT). A coordination structure is found to be critical to the mechanism of extractive desulfurization. Interaction energy and extractive selectivity follow the order: thiophene (TH)

Mathematical modeling of liquid/liquid hollow fiber membrane contactor accounting for interfacial transport phenomena: Extraction of lanthanides as a surrogate for actinides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rogers, J.D.

1994-08-04

This report is divided into two parts. The second part is divided into the following sections: experimental protocol; modeling the hollow fiber extractor using film theory; Graetz model of the hollow fiber membrane process; fundamental diffusive-kinetic model; and diffusive liquid membrane device-a rigorous model. The first part is divided into: membrane and membrane process-a concept; metal extraction; kinetics of metal extraction; modeling the membrane contactor; and interfacial phenomenon-boundary conditions-applied to membrane transport.

Use of magnetic effervescent tablet-assisted ionic liquid dispersive liquid-liquid microextraction to extract fungicides from environmental waters with the aid of experimental design methodology.

PubMed

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

2016-02-04

In this work, a novel effervescence-assisted microextraction technique was proposed for the detection of four fungicides. This method combines ionic liquid-based dispersive liquid-liquid microextraction with the magnetic retrieval of the extractant. A magnetic effervescent tablet composed of Fe3O4 magnetic nanoparticles, sodium carbonate, sodium dihydrogen phosphate and 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonimide) was used for extractant dispersion and retrieval. The main factors affecting the extraction efficiency were screened by a Plackett-Burman design and optimized by a central composite design. Under the optimum conditions, good linearity was obtained for all analytes in pure water model and real water samples. Just for the pure water, the recoveries were between 84.6% and 112.8%, the limits of detection were between 0.02 and 0.10 μg L(-1) and the intra-day precision and inter-day precision both are lower than 4.9%. This optimized method was successfully applied in the analysis of four fungicides (azoxystrobin, triazolone, cyprodinil, trifloxystrobin) in environmental water samples and the recoveries ranged between 70.7% and 105%. The procedure promising to be a time-saving, environmentally friendly, and efficient field sampling technique. Copyright © 2015 Elsevier B.V. All rights reserved.

Aluminium sensitized spectrofluorimetric determination of fluoroquinolones in milk samples coupled with salting-out assisted liquid-liquid ultrasonic extraction

NASA Astrophysics Data System (ADS)

Xia, Qinghai; Yang, Yaling; Liu, Mousheng

2012-10-01

An aluminium sensitized spectrofluorimetric method coupled with salting-out assisted liquid-liquid ultrasonic extraction for the determination of four widely used fluoroquinolones (FQs) namely norfloxacin (NOR), ofloxacin (OFL), ciprofloxacin (CIP) and gatifloxacin (GAT) in bovine raw milk was described. The analytical procedure involves the fluorescence sensitization of aluminium (Al3+) by complexation with FQs, salting-out assisted liquid-liquid ultrasonic extraction (SALLUE), followed by spectrofluorometry. The influence of several parameters on the extraction (the salt species, the amount of salt, pH, temperature and phase volume ratio) was investigated. Under optimized experimental conditions, the detection limits of the method in milk varied from 0.009 μg/mL for NOR to 0.016 μg/mL for GAT (signal-to-noise ratio (S/N) = 3). The relative standard deviations (RSD) values were found to be relatively low (0.54-2.48% for four compounds). The calibration graph was linear from 0.015 to 2.25 μg/mL with coefficient of determinations not less than 0.9974. The methodology developed was applied to the determination of FQs in bovine raw milk samples. The main advantage of this method is simple, accurate and green. The method showed promising applications for analyzing polar analytes especially polar drugs in various sample matrices.

Rapid determination of polycyclic aromatic hydrocarbons in rainwater by liquid-liquid microextraction and LC with core-shell particles column and fluorescence detection.

PubMed

Vinci, Giuliana; Antonelli, Marta L; Preti, Raffaella

2013-02-01

Liquid-liquid microextraction coupled to LC with fluorescence detection for the determination of Environmental Protection Agency's 16 priority pollutant polycyclic aromatic hydrocarbons in rainwater has been developed. The optimization of the extraction method has involved several parameters, including the comparison between an ultrasonic bath and a magnetic stirrer as extractant apparatus, the choice of the extractant solvent, and the optimization of the extraction time. Liquid-liquid microextraction gave good results in terms of recoveries (from 73.6 to 102.8% in rainwater) and repeatability, with a very simple procedure and low solvent consumption. The reported chromatographic method uses a Core-Shell technology column, with particle size <3 μm instead of classical 5-μm particles column. The resulting backpressure was below 300 bar, allowing the use of a conventional HPLC system rather than the more expensive ultrahigh performance LC (UHPLC). An average decrease of 59% in run time and 75% in eluent consumption has been obtained, compared to classical HPLC methods, keeping good separation, sensitivity, and repeatability. The proposed conditions were successfully applied to the determinations of polycyclic aromatic hydrocarbons in genuine rainwater samples. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

PubMed

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.

Simultaneous Determination of 13 Priority Polycyclic Aromatic Hydrocarbons in Tehran’s Tap Water and Water for Injection Samples Using Dispersive Liquid-Liquid Micro Extraction Method and Gas Chromatography-Mass Spectrometry

PubMed Central

Sadeghi, Ramezan; Kobarfard, Farzad; Yazdanpanah, Hassan; Eslamizad, Samira; Bayate, Mitra

2016-01-01

Polycyclic aromatic hydrocarbons (PAHs) are classified as persistent and carcinogenic organic pollutants. PAHs contamination has been reported in water. Many of relevant regulatory bodies such as EU and EPA have regulated the limit levels for PAHs in drinking water. In this study, 13 priority polycyclic aromatic hydrocarbons (PAHs) were determined in tap water samples of Tehran and water for injection. Dispersive liquid-liquid microextraction procedure combined with gas chromatography-mass spectrometry was used for the extraction and determination of PAHs in the samples. Under the optimized conditions, the range of extraction recoveries and relative standard deviations (RSDs) of PAHs in water using internal standard (anthracene-d10) were in the range of 71-90% and 4-16%, respectively. Limit of detection for different PAHs were between 0.03 and 0.1 ngmL-1. The concentration of PAHs in all tap water as well as water for injection samples were lower than the limit of quantification of PAHs. This is the first study addressing the occurrence of PAHs in water for injection samples in Iran using dispersive liquid-liquid micro extraction procedure combined with gas chromatography-mass spectrometry. PMID:27642318

Determination of metal ions in tea samples using task-specific ionic liquid-based ultrasound-assisted dispersive liquid-liquid microextraction coupled to liquid chromatography with ultraviolet detection.

PubMed

Werner, Justyna

2016-04-01

Task-specific ionic liquid-based ultrasound-assisted dispersive liquid-liquid microextraction was used for the preconcentration of cadmium(II), cobalt(II), and lead(II) ions in tea samples, which were subsequently analyzed by liquid chromatography with UV detection. The proposed method of preconcentration is free of volatile organic compounds, which are often used as extractants and dispersing solvents in classic techniques of microextraction. A task-specific ionic liquid trioctylmethylammonium thiosalicylate was used as an extractant and a chelating agent. Ultrasound was used to disperse the ionic liquid. After microextraction, the phases were separated by centrifugation, and the ionic liquid phase was solubilized in methanol and directly injected into the liquid chromatograph. Selected microextraction parameters, such as the volume of ionic liquid, the pH of the sample, the duration of ultrasound treatment, the speed and time of centrifugation, and the effect of ionic strength, were optimized. Under optimal conditions an enrichment factor of 200 was obtained for each analyte. The limits of detection were 0.002 mg/kg for Cd(II), 0.009 mg/kg for Co(II), and 0.013 mg/kg for Pb(II). The accuracy of the proposed method was evaluated by an analysis of the Certified Reference Materials (INCT-TL-1, INCT-MPH-2) with the recovery values in the range of 90-104%. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Extraction of mercury(II) with sulfurized jojoba oil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wisniak, J.; Schorr, G.; Zacovsky, D.

1990-09-01

Sulfurized jojoba oil containing 12% by weight S has been tested as an extractant for Hg(II) from aqueous solutions. This paper reports on experiments performed with the extractant dissolved in a solvent (liquid--liquid extraction) or adsorbed in an appropriate resin matrix (solid--liquid extraction). The extraction characteristics of both systems have been measured and show that sulfurized jojoba oil exhibits very good possibilities as an extractant. The performance of several resins treated with sulfurized jojoba oil for adsorbing mercury(II) was studied. The morphology of the different resins was examined by using scanning electron microscopy. The sulfurized oil is attached to themore » resin sites through the sulfur atoms; it is estimated that there are about 2 mol of S active sites per kilogram of resin.« less

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

PubMed

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.

Enantioselective reductive transformation of climbazole: A concept towards quantitative biodegradation assessment in anaerobic biological treatment processes.

PubMed

Brienza, Monica; Chiron, Serge

2017-06-01

An efficient chiral method-based using liquid chromatography-high resolution-mass spectrometry analytical method has been validated for the determination of climbazole (CBZ) enantiomers in wastewater and sludge with quantification limits below the 1 ng/L and 2 ng/g range, respectively. On the basis of this newly developed analytical method, the stereochemistry of CBZ was investigated over time in sludge biotic and sterile batch experiments under anoxic dark and light conditions and during wastewater biological treatment by subsurface flow constructed wetlands. CBZ stereoselective degradation was exclusively observed under biotic conditions, confirming the specificity of enantiomeric fraction variations to biodegradation processes. Abiotic CBZ enantiomerization was insignificant at circumneutral pH and CBZ was always biotransformed into CBZ-alcohol due to the specific and enantioselective reduction of the ketone function of CBZ into a secondary alcohol function. This transformation was almost quantitative and biodegradation gave good first order kinetic fit for both enantiomers. The possibility to apply the Rayleigh equation to enantioselective CBZ biodegradation processes was investigated. The results of enantiomeric enrichment allowed for a quantitative assessment of in situ biodegradation processes due to a good fit (R 2  > 0.96) of the anoxic/anaerobic CBZ biodegradation to the Rayleigh dependency in all the biotic microcosms and was also applied in subsurface flow constructed wetlands. This work extended the concept of applying the Rayleigh equation towards quantitative biodegradation assessment of organic contaminants to enantioselective processes operating under anoxic/anaerobic conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Theory of hydrophobicity: transient cavities in molecular liquids

NASA Technical Reports Server (NTRS)

Pratt, L. R.; Pohorille, A.

1992-01-01

Observation of the size distribution of transient cavities in computer simulations of water, n-hexane, and n-dodecane under benchtop conditions shows that the sizes of cavities are more sharply defined in liquid water but the most-probable-size cavities are about the same size in each of these liquids. The calculated solvent atomic density in contact with these cavities shows that water applies more force per unit area of cavity surface than do the hydrocarbon liquids. This contact density, or "squeezing" force, reaches a maximum near cavity diameters of 2.4 angstroms. The results for liquid water are compared to the predictions of simple theories and, in addition, to results for a reference simple liquid. The numerical data for water at a range of temperatures are analyzed to extract a surface free energy contribution to the work of formation of atomic-size cavities. Comparison with the liquid-vapor interfacial tensions of the model liquids studied here indicates that the surface free energies extracted for atomic-size cavities cannot be accurately identified with the macroscopic surface tensions of the systems.

Theory of hydrophobicity: Transient cavities in molecular liquids

PubMed Central

Pratt, Lawrence R.; Pohorille, Andrew

1992-01-01

Observation of the size distribution of transient cavities in computer simulations of water, n-hexane, and n-dodecane under benchtop conditions shows that the sizes of cavities are more sharply defined in liquid water but the most-probable-size cavities are about the same size in each of these liquids. The calculated solvent atomic density in contact with these cavities shows that water applies more force per unit area of cavity surface than do the hydrocarbon liquids. This contact density, or “squeezing” force, reaches a maximum near cavity diameters of 2.4 Å. The results for liquid water are compared to the predictions of simple theories and, in addition, to results for a reference simple liquid. The numerical data for water at a range of temperatures are analyzed to extract a surface free energy contribution to the work of formation of atomic-size cavities. Comparison with the liquid-vapor interfacial tensions of the model liquids studies here indicates that the surface free energies extracted for atomic-size cavities cannot be accurately identified with the macroscopic surface tensions of the systems. PMID:11537863

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

PubMed

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

2013-03-01

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

Lipophilic ternary complexes in liquid-liquid extraction of trivalent lanthanides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lumetta, Gregg J.; Levitskaia, Tatiana G.; Latesky, Stanley

2012-03-01

The formation of ternary complexes between lanthanide ions [Nd(III) or Eu(III)], octyl(phenyl)-N,N-diisobutyl-carbamoylmethylphosphine oxide (CMPO), and bis-(2-ethylhexyl)phosphoric acid (HDEHP) was probed by liquid-liquid extraction and spectroscopic techniques. Equilibrium modeling of data for the extraction of Nd(III) or Eu(III) from lactic acid media into n-dodecane solutions of CMPO and HDEHP indicates the predominant extracted species are of the type [Ln(AHA){sub 2}(A)] and [Ln(CMPO)(AHA){sub 2}(A)], where Ln = Nd or Eu and A represents the DEHP{sup -} anion. FTIR (for both Eu and Nd) and visible spectrophotometry (in the case of Nd) indicate the formation of the [Ln(CMPO)(A){sup 3}] complexes when CMPO ismore » added to n-dodecane solutions of the LnA{sub 3} compounds. Both techniques indicate a stronger propensity of CMPO to complex Nd(III) versus Eu(III).« less

Isolation and recovery of selected polybrominated diphenyl ethers from human serum and sheep serum: coupling reversed-phase solid-phase disk extraction and liquid-liquid extraction techniques with a capillary gas chromatographic electron capture negative ion mass spectrometric determinative technique.

PubMed

Loconto, Paul R; Isenga, David; O'Keefe, Michael; Knottnerus, Mark

2008-01-01

Polybrominated diphenyl ethers (PBDEs) are isolated and recovered with acceptable percent recoveries from human serum via liquid-liquid extraction and column chromatographic cleanup and fractionation with quantitation using capillary gas chromatography-mass spectrometry with electron capture negative ion and selected ion monitoring. PBDEs are found in unspiked serum. An alternative sample preparation approach is developed using sheep serum that utilizes a formic acid pre-treatment followed by reversed-phase solid-phase disk extraction and normal-phase solid-phase cleanup using acidified silica gel that yields>50% recoveries. When these percent recoveries are combined with a minimized phase ratio for human serum and very low instrument detection limits, method detection limits below 500 parts-per-trillion are realized.

Simultaneous determination of dextromethorphan, dextrorphan, and guaifenesin in human plasma using semi-automated liquid/liquid extraction and gradient liquid chromatography tandem mass spectrometry.

PubMed

Eichhold, Thomas H; McCauley-Myers, David L; Khambe, Deepa A; Thompson, Gary A; Hoke, Steven H

2007-01-17

A method for the simultaneous determination of dextromethorphan (DEX), dextrorphan (DET), and guaifenesin (GG) in human plasma was developed, validated, and applied to determine plasma concentrations of these compounds in samples from six clinical pharmacokinetic (PK) studies. Semi-automated liquid handling systems were used to perform the majority of the sample manipulation including liquid/liquid extraction (LLE) of the analytes from human plasma. Stable-isotope-labeled analogues were utilized as internal standards (ISTDs) for each analyte to facilitate accurate and precise quantification. Extracts were analyzed using gradient liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Use of semi-automated LLE with LC-MS/MS proved to be a very rugged and reliable approach for analysis of more than 6200 clinical study samples. The lower limit of quantification was validated at 0.010, 0.010, and 1.0 ng/mL of plasma for DEX, DET, and GG, respectively. Accuracy and precision of quality control (QC) samples for all three analytes met FDA Guidance criteria of +/-15% for average QC accuracy with coefficients of variation less than 15%. Data from the thorough evaluation of the method during development, validation, and application are presented to characterize selectivity, linearity, over-range sample analysis, accuracy, precision, autosampler carry-over, ruggedness, extraction efficiency, ionization suppression, and stability. Pharmacokinetic data are also provided to illustrate improvements in systemic drug and metabolite concentration-time profiles that were achieved by formulation optimization.

[Optimization of Polysaccharide Extraction from Spirodela polyrrhiza by Plackett-Burman Design Combined with Box-Behnken Response Surface Methodology].

PubMed

Jiang, Zheng; Wang, Hong; Wu, Qi-nan

2015-06-01

To optimize the processing of polysaccharide extraction from Spirodela polyrrhiza. Five factors related to extraction rate of polysaccharide were optimized by the Plackett-Burman design. Based on this study, three factors, including alcohol volume fraction, extraction temperature and ratio of material to liquid, were regarded as investigation factors by Box-Behnken response surface methodology. The effect order of three factors on the extraction rate of polysaccharide from Spirodela polyrrhiza were as follows: extraction temperature, alcohol volume fraction,ratio of material to liquid. According to Box-Behnken response, the best extraction conditions were: alcohol volume fraction of 81%, ratio of material to liquid of 1:42, extraction temperature of 100 degrees C, extraction time of 60 min for four times. Plackett-Burman design and Box-Behnken response surface methodology used to optimize the extraction process for the polysaccharide in this study is effective and stable.

Dynamic Mass Transfer of Hemoglobin at the Aqueous/Ionic-Liquid Interface Monitored with Liquid Core Optical Waveguide.

PubMed

Chen, Xuwei; Yang, Xu; Zeng, Wanying; Wang, Jianhua

2015-08-04

Protein transfer from aqueous medium into ionic liquid is an important approach for the isolation of proteins of interest from complex biological samples. We hereby report a solid-cladding/liquid-core/liquid-cladding sandwich optical waveguide system for the purpose of monitoring the dynamic mass-transfer behaviors of hemoglobin (Hb) at the aqueous/ionic liquid interface. The optical waveguide system is fabricated by using a hydrophobic IL (1,3-dibutylimidazolium hexafluorophosphate, BBimPF6) as the core, and protein solution as one of the cladding layer. UV-vis spectra are recorded with a CCD spectrophotometer via optical fibers. The recorded spectra suggest that the mass transfer of Hb molecules between the aqueous and ionic liquid media involve accumulation of Hb on the aqueous/IL interface followed by dynamic extraction/transfer of Hb into the ionic liquid phase. A part of Hb molecules remain at the interface even after the accomplishment of the extraction/transfer process. Further investigations indicate that the mass transfer of Hb from aqueous medium into the ionic liquid phase is mainly driven by the coordination interaction between heme group of Hb and the cationic moiety of ionic liquid, for example, imidazolium cation in this particular case. In addition, hydrophobic interactions also contribute to the transfer of Hb.

Recovery of phenolic compounds from grape seeds: effect of extraction time and solid-liquid ratio.

PubMed

Casazza, Alessandro A; Aliakbarian, Bahar; Perego, Patrizia

2011-10-01

The aim of this research was to study the recovery of phenolic compounds from grape seeds, by-products from winemaking industries, using ethanolic solid-liquid extraction. For such a purpose, the combined effects of the extraction time (9, 19 and 29 h) and the solid-liquid ratio (0.10, 0.20 and 0.30 gdw mL(-1)), were investigated (where dw = dry waste). Results demonstrated that Pinot Noir seeds had high levels of both total polyphenols (73.66 mg(Gallic Acid Equivalent) gdw(-1)) and flavonoids (30.90 mg(Catechin Equivalent) gdw(-1)), being the optimum extraction time 19 h approximately. The main phenolic compounds analysed with high performance liquid chromatography were catechin and quercetin with a maximum extraction yield obtained at 29 h (362.23 and 339.35 mg/100 gdw, respectively). Concentration of the polyphenols and their antiradical powers are demonstrated to have a significant linear correlation.

Automated dynamic liquid-liquid-liquid microextraction followed by high-performance liquid chromatography-ultraviolet detection for the determination of phenoxy acid herbicides in environmental waters.

PubMed

Wu, Jingming; Ee, Kim Huey; Lee, Hian Kee

2005-08-05

Automated dynamic liquid-liquid-liquid microextraction (D-LLLME) controlled by a programmable syringe pump and combined with HPLC-UV was investigated for the extraction and determination of 5 phenoxy acid herbicides in aqueous samples. In the extraction procedure, the acceptor phase was repeatedly withdrawn into and discharged from the hollow fiber by the syringe pump. The repetitive movement of acceptor phase into and out of the hollow fiber channel facilitated the transfer of analytes into donor phase, from the organic phase held in the pore of the fiber. Parameters such as the organic solvent, concentrations of the donor and acceptor phases, plunger movement pattern, speed of agitation and ionic strength of donor phase were evaluated. Good linearity of analytes was achieved in the range of 0.5-500 ng/ml with coefficients of determination, r2 > 0.9994. Good repeatabilities of extraction performance were obtained with relative standard deviations lower than 7.5%. The method provided up-to 490-fold enrichment within 13 min. In addition, the limits of detection (LODs) ranged from 0.1 to 0.4 ng/mL (S/N = 3). D-LLLME was successfully applied for the analysis of phenoxy acid herbicides from real environmental water samples.

[Preparation and applications of a supported liquid-liquid extraction column with a composite diatomite material].

PubMed

Bao, Jianmin; Ma, Zhishuang; Sun, Ying; Wang, Yongzun; Li, Youxin

2012-08-01

A rapid and special supported liquid-liquid extraction (SLE) column was developed with a composite diatomite material. The SLE column was evaluated by high performance liquid chromatography (HPLC) with acidic, neutral and alkaline compounds dissolved in water. Furthermore, some real complex samples were also analyzed by HPLC with the SLE method. The recoveries of benzoic acid (acidic), p-nitroaniline (alkaline) and 4-hydroxy-benzoic methyl ester (neutral) treated by the SLE column were 90.6%, 98.1% and 97.7%. However, the recoveries of the three compounds treated by traditional liquid-liquid extraction (LLE) method were 71.9%, 81.9% and 83.9%. The results showed that the SLE technique had higher recoveries than the traditional LLE method. The spiked recoveries of the complex samples, such as benzoic acid in Sprite and dexamethasone acetate, chlorphenamine maleate, indomethacin in bovine serum, were between 80% and 110% and the relative standard deviations (RSDs) were less than 15%. For biological specimen, the results could be accepted. Meantime, many disadvantages associated with traditional LLE method, such as emulsion formation, didn't occur using SLE column. The SLE column technique is a good sample preparation method with many advantages, such as rapid, simple, robust, easily automated, high recovery and high-throughput, which would be widely used in the future.

Modification of the fluorescent antibody virus neutralisation test--elimination of the cytotoxic effect for the detection of rabies virus neutralising antibodies.

PubMed

Bedeković, Tomislav; Lemo, Nina; Lojkić, Ivana; Mihaljević, Zeljko; Jungić, Andreja; Cvetnić, Zeljko; Cač, Zeljko; Hostnik, Peter

2013-04-01

The virus neutralisation test is used for the quantitation of specific antibodies in serum samples. However, the success of the test depends on the quality of samples. In the case of poor quality samples, a cytotoxic effect can be observed and the results of the test can be compromised. Additionally, the cytotoxic effect limits the use of different substances, such as muscle extract or liquid from thoracic cavity (thoracic liquid), as a sample for the detection of rabies virus neutralising antibodies in the follow-up of fox oral vaccination campaigns. To eliminate the cytotoxic effect, a modified fluorescent antibody virus neutralisation (mFAVN) test was developed and evaluated. In the mFAVN test, inocula were removed after a 1h and the cytotoxic effect was prevented. According to the results obtained, the specificity of the mFAVN test compared to the FAVN test was 88.8% and the sensitivity was 94.4%. The diagnostic validity of the test was 0.99 (CI=0.98-1.00). To evaluate the possibility of using muscle extract and thoracic liquid as samples for the virus neutralisation test, 102 sera, muscle extract and thoracic liquid samples of dog origin were tested with the mFAVN test. The correlation between sera and muscle extracts was 87.9% (r=0.88, p<0.001). The correlation between sera and thoracic liquid was 94.2% (r=0.94, p<0.001). These findings indicated that both muscle extract and thoracic liquid could be used as samples for detection of rabies virus neutralising antibodies in the follow-up of oral vaccination campaigns. To evaluate the level of elimination of the cytotoxic effect, the 102 samples of sera, muscle extracts and thoracic liquid of dog origin were also tested in parallel using the mFAVN and FAVN tests. In the mFAVN test, no instance of cytotoxic effect was observed in the cells. In the FAVN test, two sera (1.9%), 35 muscle extracts (34.3%) and 56 thoracic liquid samples (54.9%) showed cytotoxic effect. The results of this study strongly suggest that cytotoxic effect can be eliminated completely from the rabies virus neutralising antibody detection tests used in the follow-up of oral vaccination campaigns and that very poor quality samples, such as muscle extract and thoracic liquid, can be used. Copyright © 2013 Elsevier B.V. All rights reserved.

Enantioseparation by Capillary Electrophoresis Using Ionic Liquids as Chiral Selectors.

PubMed

Greño, Maider; Marina, María Luisa; Castro-Puyana, María

2018-11-02

Capillary electrophoresis (CE) is one of the most widely employed analytical techniques to achieve enantiomeric separations. In spite of the fact that there are many chiral selectors commercially available to perform enantioseparations by CE, one of the most relevant topics in this field is the search for new selectors capable of providing high enantiomeric resolutions. Chiral ionic liquids (CILs) have interesting characteristics conferring them a high potential in chiral separations although only some of them are commercially available. The aim of this article is to review all the works published on the use of CILs as chiral selectors in the development of enantioselective methodologies by CE, covering the period from 2006 (when the first research work on this topic was published) to 2017. The use of CILs as sole chiral selectors, as chiral selectors in dual systems or as chiral ligands will be considered. This review also provides detailed analytical information on the experimental conditions used to carry out enantioseparations in different fields as well as on the separation mechanism involved.

Simultaneous dispersive liquid-liquid microextraction derivatisation and gas chromatography mass spectrometry analysis of subcritical water extracts of sweet and sour cherry stems.

PubMed

Švarc-Gajić, Jaroslava; Clavijo, Sabrina; Suárez, Ruth; Cvetanović, Aleksandra; Cerdà, Víctor

2018-03-01

Cherry stems have been used in traditional medicine mostly for the treatment of urinary tract infections. Extraction with subcritical water, according to its selectivity, efficiency and other aspects, differs substantially from conventional extraction techniques. The complexity of plant subcritical water extracts is due to the ability of subcritical water to extract different chemical classes of different physico-chemical properties and polarities in a single run. In this paper, dispersive liquid-liquid microextraction (DLLME) with simultaneous derivatisation was optimised for the analysis of complex subcritical water extracts of cherry stems to allow simple and rapid preparation prior to gas chromatography-mass spectrometry (GC-MS). After defining optimal extracting and dispersive solvents, the optimised method was used for the identification of compounds belonging to different chemical classes in a single analytical run. The developed sample preparation protocol enabled simultaneous extraction and derivatisation, as well as convenient coupling with GC-MS analysis, reducing the analysis time and number of steps. The applied analytical protocol allowed simple and rapid chemical screening of subcritical water extracts and was used for the comparison of subcritical water extracts of sweet and sour cherry stems. Graphical abstract DLLME GC MS analysis of cherry stem extracts obtained by subcritical water.

Semi-automated 96-well liquid-liquid extraction for quantitation of drugs in biological fluids.

PubMed

Zhang, N; Hoffman, K L; Li, W; Rossi, D T

2000-02-01

A semi-automated liquid-liquid extraction (LLE) technique for biological fluid sample preparation was introduced for the quantitation of four drugs in rat plasma. All liquid transferring during the sample preparation was automated using a Tomtec Quadra 96 Model 320 liquid handling robot, which processed up to 96 samples in parallel. The samples were either in 96-deep-well plate or tube-rack format. One plate of samples can be prepared in approximately 1.5 h, and the 96-well plate is directly compatible with the autosampler of an LC/MS system. Selection of organic solvents and recoveries are discussed. Also, precision, relative error, linearity and quantitation of the semi automated LLE method are estimated for four example drugs using LC/MS/MS with a multiple reaction monitoring (MRM) approach. The applicability of this method and future directions are evaluated.

Fast and sensitive analysis of beta blockers by ultra-high-performance liquid chromatography coupled with ultra-high-resolution TOF mass spectrometry.

PubMed

Tomková, Jana; Ondra, Peter; Kocianová, Eva; Václavík, Jan

2017-07-01

This paper presents a method for the determination of acebutolol, betaxolol, bisoprolol, metoprolol, nebivolol and sotalol in human serum by liquid-liquid extraction and ultra-high-performance liquid chromatography coupled with ultra-high-resolution TOF mass spectrometry. After liquid-liquid extraction, beta blockers were separated on a reverse-phase analytical column (Acclaim RS 120; 100 × 2.1 mm, 2.2 μm). The total run time was 6 min for each sample. Linearity, limit of detection, limit of quantification, matrix effects, specificity, precision, accuracy, recovery and sample stability were evaluated. The method was successfully applied to the therapeutic drug monitoring of 108 patients with hypertension. This method was also used for determination of beta blockers in 33 intoxicated patients. Copyright © 2016 John Wiley & Sons, Ltd.

Synergistic effect of dicarbollide anions in liquid-liquid extraction: a molecular dynamics study at the octanol-water interface.

PubMed

Chevrot, G; Schurhammer, R; Wipff, G

2007-04-28

We report a molecular dynamics study of chlorinated cobalt bis(dicarbollide) anions [(B(9)C(2)H(8)Cl(3))(2)Co](-)"CCD(-)" in octanol and at the octanol-water interface, with the main aim to understand why these hydrophobic species act as strong synergists in assisted liquid-liquid cation extraction. Neat octanol is quite heterogeneous and is found to display dual solvation properties, allowing to well solubilize CCD(-), Cs(+) salts in the form of diluted pairs or oligomers, without displaying aggregation. At the aqueous interface, octanol behaves as an amphiphile, forming either monolayers or bilayers, depending on the initial state and confinement conditions. In biphasic octanol-water systems, CCD(-) anions are found to mainly partition to the organic phase, thus attracting Cs(+) or even more hydrophilic counterions like Eu(3+) into that phase. The remaining CCD(-) anions adsorb at the interface, but are less surface active than at the chloroform interface. Finally, we compare the interfacial behavior of the Eu(BTP)(3)(3+) complex in the absence and in the presence of CCD(-) anions and extractant molecules. It is found that when the CCD(-)'s are concentrated enough, the complex is extracted to the octanol phase. Otherwise, it is trapped at the interface, attracted by water. These results are compared to those obtained with chloroform as organic phase and discussed in the context of synergistic effect of CCD(-) in liquid-liquid extraction, pointing to the importance of dual solvation properties of octanol and of the hydrophobic character of CCD(-) for synergistic extraction of cations.

Acid-switched Eu(III) coordination inside reverse aggregates: Insights into a synergistic liquid-liquid extraction system

DOE PAGES

Ellis, Ross J.

2016-08-09

Determining the structure of complex solutions bearing metal ions is challenging, but crucial for developing important technologies such as liquid-liquid extraction for metal refining and separation purposes. Herein, the structure of an organic Eu(III) solution consisting a binary mixture of lipophilic ligands di-2-ethylhexyl phosphoric acid (HDEHP) and tetraoctyl diglycolamide (TODGA) in dodecane is studied using synchrotron small angle X-ray scattering (SAXS) and X-ray absorption fine structure spectroscopy (EXAFS). This system is of technological importance in f-element separation for nuclear fuel cycle applications, where extraction is controlled by varying nitric acid concentration. Extraction is promoted at low and high concentration, butmore » is retarded at intermediate concentration, leading to a U-shaped function; the structural origins of which we investigate. At the nanoscale, the solution is apparently comprised of reverse micelles with polar cores of approximately 1 nm in size, and these remain virtually unchanged as acid concentration is varied. Inside the polar cores, the coordination environment of Eu(III) switches from a 9-coordinate [Eu(TODGA) 3] 3+ motif at high acid, to a 6-coordinate HDEHP-dominated complex resembling Eu(HDEHP·DEHP) 3 at low acid. The results show that extraction is controlled within the coordination sphere, where it is promoted under conditions that favor coordination of either one of the two organic ligands, but is retarded under conditions that encourage mixed complexes. Lastly, our results link solution structure with ion transport properties in a technologically-important liquid-liquid ion extraction system.« less

Magnetomotive room temperature dicationic ionic liquid: a new concept toward centrifuge-less dispersive liquid-liquid microextraction.

PubMed

Beiraghi, Asadollah; Shokri, Masood; Seidi, Shahram; Godajdar, Bijan Mombani

2015-01-09

A new centrifuge-less dispersive liquid-liquid microextraction technique based on application of magnetomotive room temperature dicationic ionic liquid followed by electrothermal atomic absorption spectrometry (ETAAS) was developed for preconcentration and determination of trace amount of gold and silver in water and ore samples, for the first time. Magnetic ionic liquids not only have the excellent properties of ionic liquids but also exhibit strong response to an external magnetic field. These properties provide more advantages and potential application prospects for magnetic ionic liquids than conventional ones in the fields of extraction processes. In this work, thio-Michler's ketone (TMK) was used as chelating agent to form Ag/Au-TMK complexes. Several important factors affecting extraction efficiency including extraction time, rate of vortex agitator, pH of sample solution, concentration of the chelating agent, volume of ionic liquid as well as effects of interfering species were investigated and optimized. Under the optimal conditions, the limits of detection (LOD) were 3.2 and 7.3ngL(-1) with the preconcentration factors of 245 and 240 for Au and Ag, respectively. The precision values (RSD%, n=7) were 5.3% and 5.8% at the concentration level of 0.05μgL(-1) for Au and Ag, respectively. The relative recoveries for the spiked samples were in the acceptable range of 96-104.5%. The results demonstrated that except Hg(2+), no remarkable interferences are created by other various ions in the determination of Au and Ag, so that the tolerance limits (WIon/WAu or Ag) of major cations and anions were in the range of 250-1000. The validated method was successfully applied for the analysis of Au and Ag in some water and ore samples. Copyright © 2014 Elsevier B.V. All rights reserved.

In vitro antioxidant activity and inhibitory effect, on oleic acid-induced hepatic steatosis, of fractions and subfractions from oat (Avena sativa L.) ethanol extract

USDA-ARS?s Scientific Manuscript database

Oats (Avena sativa L.) were extracted with 80% aqueous ethanol and the extract was successively isolated by liquid-liquid partition to yield n-hexane, ethyl acetate, n-butanol and water layers. Among these extractions the ethyl acetate (EA) layer exhibited the highest total phenolic content (TPC), t...

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

PubMed

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

2016-04-01

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lorenz, Matthias; Ovchinnikova, Olga S; Van Berkel, Gary J

RATIONALE: Laser ablation provides for the possibility of sampling a large variety of surfaces with high spatial resolution. This type of sampling when employed in conjunction with liquid capture followed by nanoelectrospray ionization provides the opportunity for sensitive and prolonged interrogation of samples by mass spectrometry as well as the ability to analyze surfaces not amenable to direct liquid extraction. METHODS: A fully automated, reflection geometry, laser ablation liquid capture spot sampling system was achieved by incorporating appropriate laser fiber optics and a focusing lens into a commercially available, liquid extraction surface analysis (LESA ) ready Advion TriVersa NanoMate system.more » RESULTS: Under optimized conditions about 10% of laser ablated material could be captured in a droplet positioned vertically over the ablation region using the NanoMate robot controlled pipette. The sampling spot size area with this laser ablation liquid capture surface analysis (LA/LCSA) mode of operation (typically about 120 m x 160 m) was approximately 50 times smaller than that achievable by direct liquid extraction using LESA (ca. 1 mm diameter liquid extraction spot). The set-up was successfully applied for the analysis of ink on glass and paper as well as the endogenous components in Alstroemeria Yellow King flower petals. In a second mode of operation with a comparable sampling spot size, termed laser ablation/LESA , the laser system was used to drill through, penetrate, or otherwise expose material beneath a solvent resistant surface. Once drilled, LESA was effective in sampling soluble material exposed at that location on the surface. CONCLUSIONS: Incorporating the capability for different laser ablation liquid capture spot sampling modes of operation into a LESA ready Advion TriVersa NanoMate enhanced the spot sampling spatial resolution of this device and broadened the surface types amenable to analysis to include absorbent and solvent resistant materials.« less

Binary Solvents Dispersive Liquid-Liquid Microextraction (BS-DLLME) Method for Determination of Tramadol in Urine Using High-Performance Liquid Chromatography.

PubMed

Kiarostami, Vahid; Rouini, Mohamad-Reza; Mohammadian, Razieh; Lavasani, Hoda; Ghazaghi, Mehri

2014-02-03

Tramadol is an opioid, synthetic analog of codeine and has been used for the treatment of acute or chronic pain may be abused. In this work, a developed Dispersive liquid liquid microextraction (DLLME) as binary solvents-based dispersive liquid-liquid microextraction (BS-DLLME) combined with high performance liquid chromatography (HPLC) with fluorescence detection (FD) was employed for determination of tramadol in the urine samples. This procedure involves the use of an appropriate mixture of binary extraction solvents (70 μL CHCl3 and 30 μL ethyl acetate) and disperser solvent (600 μL acetone) for the formation of cloudy solution in 5 ml urine sample comprising tramadol and NaCl (7.5%, w/v). After centrifuging, the small droplets of extraction solvents were precipitated. In the final step, the HPLC with fluorescence detection was used for determination of tramadol in the precipitated phase. Various factors on the efficiency of the proposed procedure were investigated and optimized. The detection limit (S/N = 3) and quantification limit (S/N = 10) were found 0.2 and 0.9 μg/L, respectively. The relative standard deviations (RSD) for the extraction of 30 μg L of tramadol was found 4.1% (n = 6). The relative recoveries of tramadol from urine samples at spiking levels of 10, 30 and 60 μg/L were in the range of 95.6 - 99.6%. Compared with other methods, this method provides good figures of merit such as good repeatability, high extraction efficiency, short analysis time, simple procedure and can be used as microextraction technique for routine analysis in clinical laboratories.

Development of a multi-residue enantiomeric analysis method for 9 pesticides in soil and water by chiral liquid chromatography/tandem mass spectrometry.

PubMed

Li, Yuanbo; Dong, Fengshou; Liu, Xingang; Xu, Jun; Chen, Xiu; Han, Yongtao; Liang, Xuyang; Zheng, Yongquan

2013-04-15

A novel and sensitive chiral liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method was developed and validated for simultaneous measuring individual enantiomers of 9 pesticides including herbicides, insecticides, and fungicides in soil and water. The separation and determination were performed using reversed-phase chromatography on an amylose chiral stationary phase, a Chiralpak AD-RH column, under gradient elution using a mixture of ACN-2mM ammonium acetate in water as the mobile phase at 0.45 mL/min flow rate. The effects of three cellulose-based columns and three amylose-based columns on the separation were also investigated. The QuEChERS (acronym for Quick, Easy, Cheap, Effective, Rugged and Safe) method and solid-phase extraction (SPE) were used for the extraction and clean-up of the soil and water samples, respectively. Parameters including the matrix effect, linearity, precision, accuracy and stability were undertaken. Under optimal conditions, the mean recoveries for all enantiomers from the soil and water samples were ranged from 77.8% to 106.2% with the relative standard deviations (RSD) less than 14.2%. Good linearity (at least R(2) ≥ 0.9986) was obtained for all studied analytes in the soil and water matrix calibration curves over the range from 2.0 to 125 μg/L. The limits of detection (LOD) for all enantiomers in the soil and water were less than 1.8 μg/kg or μg/L, whereas the limit of quantification (LOQ) did not exceed 5.0 μg/kg or μg/L. The results of the method validation confirm that this proposed method is convenient and reliable for the enantioselective determination of the enantiomers of 9 chiral pesticides in soil and water. Copyright © 2013 Elsevier B.V. All rights reserved.

Genotoxicity of wastewaters used for irrigation of food crops.

PubMed

Ansari, Mohd Ikram; Malik, Abdul

2009-04-01

In most towns of India, wastewater coming from both industrial and domestic sources and without any treatment is used to irrigate the agricultural crops. This practice has been polluting the soil, and pollutants could possibly reach the food chain. For the above reasons, the wastewaters of Ghaziabad City (India), which is used for irrigation, were sampled (at two different sites) and monitored for the presence of genotoxic agents from January 2005 to June 2007. Gas chromatographic analysis showed the presence of certain OC (DDE, DDT, Dieldrin, Aldrin, and Endosulfan) and OP (Dimethoate, Malathion, Methlyparathion, and Chlorpyrifos) pesticides in both the sampling sites. Wastewater samples were concentrated using XAD resins (XAD-4 and XAD-8) and liquid-liquid extraction procedures, and the extracts were assayed for genotoxic potential by Ames Salmonella/microsome test, DNA repair defective mutants, and bacteriophage lambda systems. The test samples exhibited significant mutagenicity with TA98, TA97a, and TA100 strains with the probable role of contaminating pesticides in the wastewater. However, XAD-concentrated samples were more mutagenic in both sites as compared to liquid-liquid-extracted samples. The damage in the DNA repair defective mutants in the presence of XAD-concentrated water samples were also found to be higher to that of liquid-liquid-extracted water samples at the dose level of 20 muL/mL culture. All the mutants invariably exhibited significant decline in their colony-forming units as compared to their isogenic wild-type counterparts. The survival was decreased by 81.7 and 75.5% in polA(-) strain in site I, and 76.0 and 73.5% in site II in polA(-) under the same experimental conditions after 6 h of treatment with XAD-concentrated and liquid-liquid-extracted samples, respectively. A significant decrease in the survival of bacteriophage lambda was also observed when treated with the test samples. Copyright 2008 Wiley Periodicals, Inc.

Cloud-point extraction is compatible with liquid chromatography coupled to electrospray ionization mass spectrometry for the determination of antazoline in human plasma.

PubMed

Giebułtowicz, Joanna; Kojro, Grzegorz; Piotrowski, Roman; Kułakowski, Piotr; Wroczyński, Piotr

2016-09-05

Cloud-point extraction (CPE) is attracting increasing interest in a number of analytical fields, including bioanalysis, as it provides a simple, safe and environmentally-friendly sample preparation technique. However, there are only few reports on the application of this extraction technique in liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) analysis. In this study, CPE was used for the isolation of antazoline from human plasma. To date, only one method of antazoline isolation from plasma exists-liquid-liquid extraction (LLE). The aim of this study was to prove the compatibility of CPE and LC-ESI-MS/MS and the applicability of CPE to the determination of antazoline in spiked human plasma and clinical samples. Antazoline was isolated from human plasma using Triton X-114 as a surfactant. Xylometazoline was used as an internal standard. NaOH concentration, temperature and Triton X-114 concentration were optimized. The absolute matrix effect was carefully investigated. All validation experiments met international acceptance criteria and no significant relative matrix effect was observed. The compatibility of CPE and LC-ESI-MS/MS was confirmed using clinical plasma samples. The determination of antazoline concentration in human plasma in the range 10-2500ngmL(-1) by the CPE method led to results which are equivalent to those obtained by the widely used liquid-liquid extraction method. Copyright © 2016 Elsevier B.V. All rights reserved.

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.

PubMed

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.

A Teaching Laboratory for Comprehensive Lipid Characterization from Food Samples

ERIC Educational Resources Information Center

Bendinskas, Kestutis; Weber, Benjamin; Nsouli, Tamara; Nguyen, Hoangvy V.; Joyce, Carolyn; Niri, Vadoud; Jaskolla, Thorsten W.

2014-01-01

Traditional and state-of-the-art techniques were combined to probe for various lipid classes from egg yolk and avocado qualitatively and quantitatively. A total lipid extract was isolated using liquid-liquid extraction. An aliquot of the total lipid extract was subjected to transesterification to form volatile fatty acid methyl esters suitable for…

CTEPP STANDARD OPERATING PROCEDURE FOR EXTRACTING AND PREPARING LIQUID FOOD SAMPLES FOR ANALYSIS OF POLAR ORGANIC POLLUTANTS (SOP-5.29)

EPA Science Inventory

This SOP describes the extraction and preparation of a liquid food sample for analysis of acidic persistent organic pollutants such as acid herbicides, pentachlorphenol, and 3,5,6-trichloro-2-phenol. It covers the extraction, concentration and derivatization of samples that are t...

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

PubMed

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

2008-10-31

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

Extraction of trace tilmicosin in real water samples using ionic liquid-based aqueous two-phase systems.

PubMed

Pan, Ru; Shao, Dejia; Qi, Xueyong; Wu, Yun; Fu, Wenyan; Ge, Yanru; Fu, Haizhen

2013-01-01

The effective method of ionic liquid-based aqueous two-phase extraction, which involves ionic liquid (IL) (1-butyl-3-methyllimidazolium chloride, [C4mim]Cl) and inorganic salt (K2HPO4) coupled with high-performance liquid chromatography (HPLC), has been used to extract trace tilmicosin in real water samples which were passed through a 0.45 μm filter. The effects of the different types of salts, the concentration of K2HPO4 and of ILs, the pH value and temperature of the systems on the extraction efficiencies have all been investigated. Under the optimum conditions, the average extraction efficiency is up to 95.8%. This method was feasible when applied to the analysis of tilmicosin in real water samples within the range 0.5-40 μg mL(-1). The limit of detection was found to be 0.05 μg mL(-1). The recovery rate of tilmicosin was 92.0-99.0% from the real water samples by the proposed method. This process is suggested to have important applications for the extraction of tilmicosin.

Dispersive liquid-liquid microextraction based on the solidification of floating organic droplet for the determination of polychlorinated biphenyls in aqueous samples.

PubMed

Dai, Liping; Cheng, Jing; Matsadiq, Guzalnur; Liu, Lu; Li, Jun-Kai

2010-08-03

In the proposed method, an extraction solvent with a lower toxicity and density than the solvents typically used in dispersive liquid-liquid microextraction was used to extract seven polychlorinated biphenyls (PCBs) from aqueous samples. Due to the density and melting point of the extraction solvent, the extract which forms a layer on top of aqueous sample can be collected by solidifying it at low temperatures, which form a layer on top of the aqueous sample. Furthermore, the solidified phase can be easily removed from the aqueous phase. Based on preliminary studies, 1-undecanol was selected as the extraction solvent, and a series of parameters that affect the extraction efficiency were systematically investigated. Under the optimized conditions, enrichment factors for PCBs ranged between 494 and 606. Based on a signal-to-noise ratio of 3, the limit of detection for the method ranged between 3.3 and 5.4 ng L(-1). Good linearity, reproducibility and recovery were also obtained. 2010 Elsevier B.V. All rights reserved.

Sensitive determination of nitrophenol isomers by reverse-phase high-performance liquid chromatography in conjunction with liquid-liquid extraction

USDA-ARS?s Scientific Manuscript database

A method for the highly sensitive determination of 2-, 3- and 4- nitrophenols was developed using reverse-phase high-performance liquid chromatography (RP-HPLC) with a UV photodiode array detector. Using a reverse-phase column and 40% aqueous acetonitrile as an eluent (i.e. isocratic elution), the i...

The Influence of Lactic Acid Concentration on the Separation of Light Rare Earth Elements by Continuous Liquid-Liquid Extraction with 2-Ethylhexyl Phosphonic Acid Mono-2-ethylhexyl Ester

NASA Astrophysics Data System (ADS)

de Carvalho Gomes, Rafael; Seruff, Luciana Amaral; Scal, Maira Labanca Waineraich; Vera, Ysrael Marrero

2018-02-01

The separation of rare earth elements (REEs) using solvent extraction adding complexing agents appears to be an alternative to saponification of the extractant. We evaluated the effect of lactic acid concentration on didymium (praseodymium and neodymium) and lanthanum extraction with 2-ethylhexyl phosphonic acid mono-2-ethyl hexyl ester [HEH(EHP)] as extractant. First, we investigated in batch experiments the separation of lanthanum (La) and didymium (Pr and Nd) using McCabe-Thiele diagrams to estimate the number of extraction stages when the feed solution was or was not conditioned with lactic acid. Additionally, we conducted continuous liquid-liquid extraction experiments and evaluated the influence of lactic acid concentration on the REE extraction and separation. The tests showed that the extraction percentage of REEs and the separation factor Pr/La increased when the lactic acid concentration increased, but the didymium purity decreased. Lanthanum, praseodymium, and neodymium extraction rate were 23.0, 89.7, and 99.2 pct, respectively, with 1:1 aqueous/organic volume flow rate and feed solution doped with 0.52 mol L-1 lactic acid. The highest didymium purity reached was 92.0 pct with 0.26 mol L-1 lactic acid concentration.

Separation of rare earths from transition metals by liquid-liquid extraction from a molten salt hydrate to an ionic liquid phase.

PubMed

Rout, Alok; Binnemans, Koen

2014-02-28

The solvent extraction of trivalent rare-earth ions and their separation from divalent transition metal ions using molten salt hydrates as the feed phase and an undiluted fluorine-free ionic liquid as the extracting phase were investigated in detail. The extractant was tricaprylmethylammonium nitrate, [A336][NO3], and the hydrated melt was calcium nitrate tetrahydrate, Ca(NO3)2·4H2O. The extraction behavior of rare-earth ions was studied for solutions of individual elements, as well as for mixtures of rare earths in the hydrated melt. The influence of different extraction parameters was investigated: the initial metal loading in the feed phase, percentage of water in the feed solution, equilibration time, and the type of hydrated melt. The extraction of rare earths from Ca(NO3)2·4H2O was compared with extraction from CaCl2·4H2O by [A336][Cl] (Aliquat 336). The nitrate system was found to be the better one. The extraction and separation of rare earths from the transition metals nickel, cobalt and zinc were also investigated. Remarkably high separation factors of rare-earth ions over transition metal ions were observed for extraction from Ca(NO3)2·4H2O by the [A336][NO3] extracting phase. Furthermore, rare-earth ions could be separated efficiently from transition metal ions, even in melts with very high concentrations of transition metal ions. Rare-earth oxides could be directly dissolved in the Ca(NO3)2·4H2O phase in the presence of small amounts of Al(NO3)3·9H2O or concentrated nitric acid. The efficiency of extraction after dissolving the rare-earth oxides in the hydrated nitrate melt was identical to extraction from solutions with rare-earth nitrates dissolved in the molten phase. The stripping of the rare-earth ions from the loaded ionic liquid phase and the reuse of the recycled ionic liquid were also investigated in detail.

Ionic liquid-based microwave-assisted extraction for the determination of flavonoid glycosides in pigeon pea leaves by high-performance liquid chromatography-diode array detector with pentafluorophenyl column.

PubMed

Wei, Wei; Fu, Yu-jie; Zu, Yuan-gang; Wang, Wei; Luo, Meng; Zhao, Chun-jian; Li, Chun-ying; Zhang, Lin; Wei, Zuo-fu

2012-11-01

In this study, an ionic liquid-based microwave-assisted extraction (ILMAE) followed by high-performance liquid chromatography-diode array detector with a pentafluorophenyl column for the extraction and quantification of eight flavonoid glycosides in pigeon pea leaves is described. Compared with conventional extraction methods, ILMAE is a more effective and environment friendly method for the extraction of nature compounds from herbal plants. Nine different types of ionic liquids with different cations and anions were investigated. The results suggested that varying the anion and cation had significant effects on the extraction of flavonoid glycosides, and 1.0 M 1-butyl-3-methylimidazolium bromide ([C4MIM]Br) solution was selected as solvent. In addition, the extraction procedures were also optimized using a series of single-factor experiments. The optimum parameters were obtained as follows: extraction temperature 60°C, liquid-solid ratio 20:1 mL/g and extraction time 13 min. Moreover, an HPLC method using pentafluorophenyl column was established and validated. Good linearity was observed with the regression coefficients (r(2)) more than 0.999. The limit of detection (LODs) (S/N = 3) and limit of quantification (LOQs) (S/N = 10) for the components were less than 0.41 and 1.47 μg/mL, respectively. The inter- and intraday precisions that were used to evaluate the reproducibility and relative standard deviation (RSD) values were less than 4.57%. The recoveries were between 97.26 and 102.69%. The method was successfully used for the analysis of samples of pigeon pea leaves. In conclusion, the developed ILMAE-HPLC-diode array detector using pentafluorophenyl column method can be applied for quality control of pigeon pea leaves and related medicinal products. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Combination of dispersive liquid-liquid microextraction with flame atomic absorption spectrometry using microsample introduction for determination of lead in water samples.

PubMed

Naseri, Mohammad Taghi; Hemmatkhah, Payam; Hosseini, Mohammad Reza Milani; Assadi, Yaghoub

2008-03-03

The dispersive liquid-liquid microextraction (DLLME) was combined with the flame atomic absorption spectrometry (FAAS) for determination of lead in the water samples. Diethyldithiophosphoric acid (DDTP), carbon tetrachloride and methanol were used as chelating agent, extraction solvent and disperser solvent, respectively. A new FAAS sample introduction system was employed for the microvolume nebulization of the non-flammable chlorinated organic extracts. Injection of 20 microL volumes of the organic extract into an air-acetylene flame provided very sensitive spike-like and reproducible signals. Some effective parameters on the microextraction and the complex formation were selected and optimized. These parameters include extraction and disperser solvent type as well as their volume, extraction time, salt effect, pH and amount of the chelating agent. Under the optimized conditions, the enrichment factor of 450 was obtained from a sample volume of 25.0 mL. The enhancement factor, calculated as the ratio of the slopes of the calibration graphs with and without preconcentration, which was about 1000. The calibration graph was linear in the range of 1-70 microgL(-1) with a detection limit of 0.5 microgL(-1). The relative standard deviation (R.S.D.) for seven replicate measurements of 5.0 and 50 microgL(-1) of lead were 3.8 and 2.0%, respectively. The relative recoveries of lead in tap, well, river and seawater samples at the spiking level of 20 microgL(-1) ranged from 93.8 to 106.2%. The characteristics of the proposed method were compared with those of the liquid-liquid extraction (LLE), cloud point extraction (CPE), on-line and off-line solid-phase extraction (SPE) as well as co-precipitation, based on bibliographic data. Operation simplicity, rapidity, low cost, high enrichment factor, good repeatability, and low consumption of the extraction solvent at a microliter level are the main advantages of the proposed method.

A highly selective dispersive liquid-liquid microextraction approach based on the unique fluorous affinity for the extraction and detection of per- and polyfluoroalkyl substances coupled with high performance liquid chromatography tandem-mass spectrometry.

PubMed

Wang, Juan; Shi, Yali; Cai, Yaqi

2018-04-06

In the present study, a highly selective fluorous affinity-based dispersive liquid-liquid microextraction (DLLME) technique was developed for the extraction and analysis of per- and polyfluoroalkyl substances (PFASs) followed by high performance liquid chromatography tandem-mass spectrometry. Perfluoro-tert-butanol with multiple C-F bonds was chosen as the extraction solvent, which was injected into the aqueous samples with a dispersive solvent (acetonitrile) in a 120:800 (μL, v/v) mixture for PFASs enrichment. The fluorous affinity-based extraction mechanism was confirmed by the significantly higher extraction recoveries for PFASs containing multiple fluorine atoms than those for compounds with fewer or no fluorine atoms. The extraction recoveries of medium and long-chain PFASs (CF 2  > 5) exceeded 70%, except perfluoroheptanoic acid, while those of short-chain PFASs were lower than 50%, implying that the proposed DLLME may not be suitable for their extraction due to weak fluorous affinity. This highly fluoroselective DLLME technique can greatly decrease the matrix effect that occurs in mass spectrometry detection when applied to the analysis of urine samples. Under the optimum conditions, the relative recoveries of PFASs with CF 2  > 5 ranged from 80.6-121.4% for tap water, river water and urine samples spiked with concentrations of 10, 50 and 100 ng/L. The method limits of quantification for PFASs in water and urine samples were in the range of 0.6-8.7 ng/L. Furthermore, comparable concentrations of PFASs were obtained via DLLME and solid-phase extraction, confirming that the developed DLLME technique is a promising method for the extraction of PFASs in real samples. Copyright © 2018 Elsevier B.V. All rights reserved.

A simple liquid extraction protocol for overcoming the ion suppression of triacylglycerols by phospholipids in liquid chromatography mass spectrometry studies.

PubMed

Araujo, Pedro; Tilahun, Ephrem; Breivik, Joar Fjørtoft; Abdulkader, Bashir M; Frøyland, Livar; Zeng, Yingxu

2016-02-01

It is well-known that triacylglycerol (TAG) ions are suppressed by phospholipid (PL) ions in regiospecific analysis of TAG by mass spectrometry (MS). Hence, it is essential to remove the PL during sample preparation prior to MS analysis. The present article proposes a cost-effective liquid-liquid extraction (LLE) method to remove PL from TAG in different kinds of biological samples by using methanol, hexane and water. High performance thin layer chromatography confirmed the lack of PL in krill oil and salmon liver samples, submitted to the proposed LLE protocol, and liquid chromatography tandem MS confirmed that the identified TAG ions were highly enhanced after implementing the LLE procedure. Copyright © 2015 Elsevier B.V. All rights reserved.

Solvent for the simultaneous recovery of radionuclides from liquid radioactive wastes

DOEpatents

Romanovskiy, Valeriy Nicholiavich; Smirnov, Igor V.; Babain, Vasiliy A.; Todd, Terry A.; Brewer, Ken N.

2002-01-01

The present invention relates to solvents, and methods, for selectively extracting and recovering radionuclides, especially cesium and strontium, rare earths and actinides from liquid radioactive wastes. More specifically, the invention relates to extracting agent solvent compositions comprising complex organoboron compounds, substituted polyethylene glycols, and neutral organophosphorus compounds in a diluent. The preferred solvent comprises a chlorinated cobalt dicarbollide, diphenyl-dibutylmethylenecarbamoylphosphine oxide, PEG-400, and a diluent of phenylpolyfluoroalkyl sulfone. The invention also provides a method of using the invention extracting agents to recover cesium, strontium, rare earths and actinides from liquid radioactive waste.

Method for the simultaneous recovery of radionuclides from liquid radioactive wastes using a solvent

DOEpatents

Romanovskiy, Valeriy Nicholiavich; Smirnov, Igor V.; Babain, Vasiliy A.; Todd, Terry A.; Brewer, Ken N.

2001-01-01

The present invention relates to solvents, and methods, for selectively extracting and recovering radionuclides, especially cesium and strontium, rare earths and actinides from liquid radioactive wastes. More specifically, the invention relates to extracting agent solvent compositions comprising complex organoboron compounds, substituted polyethylene glycols, and neutral organophosphorus compounds in a diluent. The preferred solvent comprises a chlorinated cobalt dicarbollide, diphenyl-dibutylmethylenecarbamoylphosphine oxide, PEG-400, and a diluent of phenylpolyfluoroalkyl sulfone. The invention also provides a method of using the invention extracting agents to recover cesium, strontium, rare earths and actinides from liquid radioactive waste.

Rapid determination of alkaloids in Macleaya cordata using ionic liquid extraction followed by multiple reaction monitoring UPLC-MS/MS analysis.

PubMed

Li, Linqiu; Huang, Mingyuan; Shao, Junli; Lin, Bokun; Shen, Qing

2017-02-20

The ultrasonic-assisted extraction (UAE) and ionic liquid based dispersive liquid-liquid microextraction (IL-DLLME) have been successfully applied in extracting of six alkaloids from M. cordata. 1-hexyl-3-methylimidazolium tetrafluoroborate ([C 6 MIM][BF 4 ]) aqueous solution was used as extraction solvent. The target analytes in raw material were deposited into a single drop of 1-hexyl-3-methylimidazolium hexafluorophosphate ([C 6 MIM][PF 6 ]), which was in situ formed by mixing [C 6 MIM][BF 4 ] and potassium hexafluorophosphate ([K][PF 6 ]. Afterwards, the extract was analyzed by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) in multiple-reaction monitoring (MRM) mode. The proposed method was fully validated in terms of linearity (0.9983-0.9992), LOD (0.080ngmL -1 ), LOQ (0.25ngmL -1 ), intra-day precision (<5.46%), inter-day precision (<6.36%), and recovery (86.42-112.48%). The results indicate that the approach of combining IL-DLLME with UPLC-MS/MS is powerful and practical for analyzing alkaloids in M. cordata., and it also has great potential for comprehensive quality control of other herbal medicines. Copyright © 2016 Elsevier B.V. All rights reserved.

Group extraction of organic compounds present in liquid samples

NASA Technical Reports Server (NTRS)

Jahnsen, Vilhelm J. (Inventor)

1976-01-01

An extraction device is disclosed comprising a tube containing a substantially inert, chemically non-reactive packing material with a large surface area to volume ratio. A sample which consists of organic compounds dissolved in a liquid, is introduced into the tube. As the sample passes through the packing material it spreads over the material's large surface area to form a thin liquid film which is held on the packing material in a stationary state. A particular group or family of compounds is extractable from the sample by passing a particular solvent system consisting of a solvent and selected reagents through the packing material. The reagents cause optimum conditions to exist for the compounds of the particular family to pass through the phase boundary between the sample liquid and the solvent of the solvent system. Thus, the compounds of the particular family are separated from the sample liquid and become dissolved in the solvent of the solvent system. The particular family of compounds dissolved in the solvent, representing an extract, exits the tube together with the solvent through the tube's nozzle, while the rest of the sample remains on the packing material in a stationary state. Subsequently, a different solvent system may be passed through the packing material to extract another family of compounds from the remaining sample on the packing material.

Skin whitening and anti-corrugation activities of glycoprotein fractions from liquid extracts of boiled sea cucumber.

PubMed

Kim, So Jung; Park, So Yun; Hong, Sun-Mee; Kwon, Eun-Hye; Lee, Taek-Kyun

2016-10-01

To determine skin whitening and wrinkle improvement efficacy, glycoprotein fractions were extracted from liquid extracts of boiled sea cucumber and their effects on tyrosine and elastase inhibitory activities were assayed. Fractions above and below 50 kDa (>50 kDa and <50 kDa) were extracted via a series of steps involving: boiling, filtering, desalting and freeze drying. Cytotoxicity, skin whitening and wrinkle-removing effects of boiled liquid were determined. Our MTT data showed that neither glycoprotein fraction of boiled liquid induces cellular cytotoxicity up to a concentration of 10 mg/mL treatment of the mouse melanoma cell line, B16F10, with 10 mg/mL >50 kDa enhanced tyrosinase and elastase inhibitory activities by 50.84% and 28.78%, respectively. Correlations of the >50 kDa concentration with tyrosinase inhibitory (R2 = 0.968) and elastase inhibitory (R2 = 0.983) efficacy were significant. >50 kDa glycoprotein fraction isolated from liquid extracts of boiled sea cucumber, which can serve as a functional cosmetic ingredient for whitening and wrinkle improvement of skin. Copyright © 2016 Hainan Medical University. Production and hosting by Elsevier B.V. All rights reserved.

Oxidative desulfurization of dibenzothiophene from model oil using ionic liquids as extracting agent

NASA Astrophysics Data System (ADS)

Taha, Mohd F.; Atikah, N.; Chong, F. K.; Shaharun, Maizatul S.

2012-09-01

The oxidative desulfurization of dibenzothiophene (DBT) from model oil (in n-dodecane) was carried out using ionic liquid as the extractant and catalyst, and hydrogen peroxide (H2O2) in combination with acetic acid (CH3COOH) and sulphuric acid (H2SO4) as the oxidant. The ionic liquids used were 1-butyl-3-methylimidazolium octyl sulphate ([Bmim][OcSO4]) and 1-butyl-3-methylimidazolium acetate ([Bmim][Ac]). The effect of the amounts of H2O2 on oxidative desulphurization of model oil was first investigated without the usage of ionic liquids at room temperature. The results indicate that greater amount of H2O2 give higher desulfurization and the maximum desulfurization in this study, i.e. 34 %, was occurred when the molar ratio of H2O2 to sulfur was 5:1. With the usage of ionic liquid and the molar ratio of 5:1 (H2O2:sulfur), the efficiency of DBT removal from model oil was increased significantly in terms of percent removal and removal time. Ionic liquid of [Bmim][OcSO4] performed better than [Bmim][Ac] with 72 % DBT removal. When molar ratio of H2O2 to sulphur was 5:1, volume ratio of ionic liquid to model oil was 1:1 and mixing time was 60 min at room temperature. The results indicate the potential of ionic liquids as the extractant and catalyst for oxidative desulfurization of hydrocarbon fuels.

Rapid determination of some psychotropic drugs in complex matrices by tandem dispersive liquid-liquid microextraction followed by high performance liquid chromatography.

PubMed

Asghari, Alireza; Fahimi, Ebrahim; Bazregar, Mohammad; Rajabi, Maryam; Boutorabi, Leila

2017-05-01

Simple and rapid determinations of some psychotropic drugs in some pharmaceutical wastewater and human plasma samples were successfully accomplished via the tandem dispersive liquid-liquid microextraction combined with high performance liquid chromatography-ultraviolet detection (TDLLME-HPLC-UV). TDLLME of the three psychotropic drugs clozapine, chlorpromazine, and thioridazine was easily performed through two consecutive dispersive liquid-liquid microextractions. By performing this convenient method, proper sample preconcentrations and clean-ups were achieved in just about 7min. In order to achieve the best extraction efficiency, the effective parameters involved were optimized. The optimal experimental conditions consisted of 100μL of CCl 4 (as the extraction organic solvent), and the pH values of 13 and 2 for the donor and acceptor phases, respectively. Under these optimum experimental conditions, the proposed TDLLME-HPLC-UV technique provided a good linearity in the range of 5-3000ngmL -1 for the three psychotropic drugs with the correlation of determinations (R 2 s) higher than 0.996. The limits of quantification (LOQs) and limits of detection (LODs) obtained were 5.0ngmL -1 and 1.0-1.5ngmL -1 , respectively. Also the proper enrichment factors (EFs) of 96, 99, and 88 for clozapine, chlorpromazine, and thioridazine, respectively, and good extraction repeatabilities (relative standard deviations below 9.3%, n=5) were obtained. Copyright © 2017 Elsevier B.V. All rights reserved.

Analysis of flavor compounds by GC/MS after liquid-liquid extraction from fruit juices

NASA Astrophysics Data System (ADS)

Tuşa, F. D.; Moldovan, Z.; Schmutzer, G.; Magdaş, D. A.; Dehelean, A.; Vlassa, M.

2012-02-01

In this work we describe a rapid method for analysis of volatile profiles of several commercial fruit juices using GC/MS instrument after liquid-liquid extraction. Volatile flavor compounds have been identified based on mass spectrum obtained in EI mode. This method allows to analyses a wide range of flavor compounds (esters, aldehydes, alcohols, terpenoids) the procedure was rapid, simple and inexpensive. Moreover, by means of volatile compounds it could be possible to distinguish between juices of organic and conventional production and those with flavorings addition. More of 20 compounds were identified and quantified as relative chromatogram area taken on larges ion in mass spectrum.

Evaluation and application of microwave-assisted extraction and dispersive liquid-liquid microextraction followed by high-performance liquid chromatography for the determination of polar heterocyclic aromatic amines in hamburger patties.

PubMed

Aeenehvand, Saeed; Toudehrousta, Zahra; Kamankesh, Marzieh; Mashayekh, Morteza; Tavakoli, Hamid Reza; Mohammadi, Abdorreza

2016-01-01

This study developed an analytical method based on microwave-assisted extraction and dispersive liquid-liquid microextraction followed by high-performance liquid chromatography for the determination of three polar heterocyclic aromatic amines from hamburger patties. Effective parameters controlling the performance of the microextraction process, such as the type and volume of extraction and disperser solvents, microwave time, nature of alkaline aqueous solution, pH and salt amount, were optimized. The calibration graphs were linear in the range of 1-200 ng g(-1), with a coefficient of determination (R(2)) better than 0.9993. The relative standard deviations (RSD) for seven analyses were between 3.2% and 6.5%. The recoveries of those compounds in hamburger patties were from 90% to 105%. Detection limits were between 0.06 and 0.21 ng g(-1). A comparison of the proposed method with the existing literature demonstrates that it is a simple, rapid, highly selective and sensitive, and it gives good enrichment factors and detection limits for determining HAAs in real hamburger patties samples. Copyright © 2015 Elsevier Ltd. All rights reserved.

Determination of desipramine in biological samples using liquid-liquid-liquid microextraction combined with in-syringe derivatization, gas chromatography, and nitrogen/phosphorus detection.

PubMed

Saraji, Mohammad; Mehrafza, Narges; Bidgoli, Ali Akbar Hajialiakbari; Jafari, Mohammad Taghi

2012-10-01

A method was established for the determination of desipramine in biological samples using liquid-liquid-liquid microextraction followed by in-syringe derivatization and gas chromatography-nitrogen phosphorus detection. The extraction method was based on the use of two immiscible organic solvents. n-Dodecane was impregnated in the pores of the hollow fiber and methanol was placed inside the lumen of the fiber as the acceptor phase. Acetic anhydride was used as the reagent for the derivatization of the analyte inside the syringe barrel. Parameters that affect the extraction efficiency (composition of donor and acceptor phase, ionic strength, sample temperature, and extraction time) as well as derivatization efficiency (amount of acetic anhydride and reaction time and temperature) were investigated. The limit of detection was 0.02 μg/L with intra and interday RSDs of 2.6 and 7.7%, respectively. The linearity of the method was in the range of 0.2-20 μg/L (r(2) = 0.9986). The method was successfully applied to determine desipramine in human plasma and urine. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Coupling of solvent-based de-emulsification dispersive liquid-liquid microextraction with high performance liquid chromatography for simultaneous simple and rapid trace monitoring of 2,4-dichlorophenoxyacetic acid and 2-methyl-4-chlorophenoxyacetic acid.

PubMed

Behbahani, Mohammad; Najafi, Fatemeh; Bagheri, Saman; Bojdi, Majid Kalate; Hassanlou, Parmoon Ghareh; Bagheri, Akbar

2014-04-01

A simple, rapid, and efficient sample pretreatment technique, based on solvent-based de-emulsification dispersive liquid-liquid microextraction (SD-DLLME), followed by high performance liquid chromatography (HPLC) has been developed for simultaneous preconcentration and trace detection of 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-methyl-4-chlorophenoxyacetic acid (MCPA) in water and urine samples. Some parameters such as acidity of solution, the amount of salt, type, and volume of extraction solvents, type of disperser/de-emulsifier solvent, and its volume were investigated and optimized. Under optimum extraction conditions, the limits of detections (LODs) of this method for MCPA and 2,4-D were 0.2 and 0.6 μg L(-1) (based on 3S(b)/m) in water and 0.4 and 1.6 μg L(-1) in urine, respectively. Furthermore, dynamic linear range of this method for MCPA and 2,4-D was 1-300 and 2-400 μg L(-1), repectively. Finally, the applicability of the proposed method was evaluated by extraction and determination of the herbicides in urine and different water samples.

Ultrasonic-assisted extraction of essential oil from Botryophora geniculate using different extracting solvents

NASA Astrophysics Data System (ADS)

Habibullah, Wilfred, Cecilia Devi

2016-11-01

This study compares the performance of ionic liquids to substitute conventional solvents (hexane, dichloromethane and methanol) to extract essential oil from Botryophora geniculate plant. Two different Ionic liquids ([C3MIM][Ac], [C4MIM][Ac]) with co-solvent diethyl ether were used in the ultrasonic-assisted extraction. The effect of various experimental conditions such as time, temperature and solvent were studied. Gas chromatography-mass spectroscopy (GC-MS) was used to analyze essential oils. The results showed that in ultrasonic-assisted extraction using ionic liquids as a solvent gave highest yield (9.5%) in 30 min at temperature 70°C. When using ultrasonic bath with hexane, dichloromethane and methanol, yields was (3.34%), (3.6%) and (3.81%) at 90 min, respectively were obtained. The ultrasonic-assisted extraction under optimal extraction conditions (time 30 min, temperature of 70°C) gave the best yield for the essential oil extraction.

Ionic liquid and aqueous two-phase extraction based on salting-out coupled with high-performance liquid chromatography for the determination of seven rare ginsenosides in Xue-Sai-Tong injection.

PubMed

Li, Lan-Jie; Jin, Yong-Ri; Wang, Xiao-Zhong; Liu, Ying; Wu, Qian; Shi, Xiao-Lei; Li, Xu-Wen

2015-09-01

A method of ionic liquid salt aqueous two-phase extraction coupled with high-performance liquid chromatography has been developed for the analysis of seven rare ginsenosides including Rg6 , F4 , 20(S)-Rg3 , 20(R)-Rg3 , Rk3 , Rk1 , and Rg5 in Xue-Sai-Tong injection. The injection was mixed with ionic liquid 1-butyl-3-methylimidazolium bromide aqueous solution, and a mixture was obtained. With the addition of sodium dodecyl sulfate and dipotassium phosphate into the mixture, the aqueous two-phase mixture was formed after ultrasonic treatment and centrifuged. Rare ginsenosides were extracted into the upper phase. To obtain a high extraction factors, various influences were considered systematically, such as the volume of ionic liquid, the category and amount of salts, the amount of sodium dodecyl sulfate, the pH value of system, and the time of ultrasonic treatment. Under the optimal condition, rare ginsenosides in Xue-Sai-Tong injection were enriched and detected, the recoveries of seven rare ginsenosides ranged from 90.05 to 112.55%, while relative standard deviations were lower than 2.50%. The developed method was reliable, rapid and sensitive for the determination of seven rare ginsenosides in the injections. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Removal of actinide elements from liquid scintillation cocktail wastes using liquid-liquid extraction and demulsification techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Foltz, K.; Landsberger, S.; Srinivasan, B.

1994-12-31

For many years liquid scintillation cocktail (LSC) wastes have been generated and stored at Argonne National Laboratory (ANL). These wastes are stored in thousands of 10--20 m scintillation vials, many of which contain elements with Z > 88. Because storage space is limited, disposal of this waste is pressing. These wastes could be commercially incinerated if the radionuclides with Z>88 are reduced to sufficiently low levels. However, there is currently no deminimus level for these radionuclides, and separation techniques are still being tested. The University of Illinois is conducting experiments to separate radionuclides with Z > 88 from simulated LSCmore » wastes by using liquid-liquid extraction (LLX) and demulsification techniques. The actinide elements are removed from the LSC by extraction into an aqueous phase after the cocktail has been demulsified. The aqueous and organic phases are separated and the organic phase, now free from radionuclides with Z > 88, can be sent to a commercial incineration facility. The aqueous phase may be treated and disposed of using existing techniques. The LLX separation techniques used solutions of sodium oxalate, aluminum nitrate, and tetrasodium EDTA at varying concentrations. These extractants were mixed with the simulated waste in a 1:1 volume ratio. Using 1.0M Na{sub 4} EDTA salt solutions, decontamination ratios as high as 230 were achieved.« less

Ringer tablet-based ionic liquid phase microextraction: Application in extraction and preconcentration of neonicotinoid insecticides from fruit juice and vegetable samples.

PubMed

Farajzadeh, Mir Ali; Bamorowat, Mahdi; Mogaddam, Mohammad Reza Afshar

2016-11-01

An efficient, reliable, sensitive, rapid, and green analytical method for the extraction and determination of neonicotinoid insecticides in aqueous samples has been developed using ionic liquid phase microextraction coupled with high performance liquid chromatography-diode array detector. In this method, a few microliters of 1-hexyl-3-methylimidazolium hexafluorophosphate (as an extractant) is added onto a ringer tablet and it is transferred into a conical test tube containing aqueous phase of the analytes. By manually shaking, the ringer tablet is dissolved and the extractant is released into the aqueous phase as very tiny droplets to provide a cloudy solution. After centrifuging the extracted analytes into ionic liquid are collected at the bottom of a conical test tube. Under the optimum extraction conditions, the method showed low limits of detection and quantification between 0.12 and 0.33 and 0.41 and 1.11ngmL(-1), respectively. Extraction recoveries and enrichment factors were from 66% to 84% and 655% to 843%, respectively. Finally different aqueous samples were successfully analyzed using the proposed method. Copyright © 2016 Elsevier B.V. All rights reserved.

Determination of parabens in human milk and other food samples by capillary electrophoresis after dispersive liquid-liquid microextraction with back-extraction.

PubMed

Alshana, Usama; Ertaş, Nusret; Göğer, Nilgün G

2015-08-15

Dispersive liquid-liquid microextraction (DLLME) with back-extraction was used prior to capillary electrophoresis (CE) for the extraction of four parabens. Optimum extraction conditions were: 200 μL chloroform (extraction solvent), 1.0 mL acetonitrile (disperser solvent) and 1 min extraction time. Back-extraction of parabens from chloroform into a 50mM sodium hydroxide solution within 10s facilitated their direct injection into CE. The analytes were separated at 12°C and 25 kV with a background electrolyte of 25 mM borate buffer containing 5.0% (v/v) acetonitrile. Enrichment factors were in the range of 4.3-10.7 and limits of detection ranged from 0.1 to 0.2 μg mL(-1). Calibration graphs showed good linearity with coefficients of determination (R(2)) higher than 0.9957 and relative standard deviations (%RSDs) lower than 3.5%. DLLME-CE was demonstrated to be a simple and rapid method for the determination of parabens in human milk and food with relative recoveries in the range of 86.7-103.3%. Copyright © 2015 Elsevier Ltd. All rights reserved.

Ionic liquid-salt aqueous two-phase extraction based on salting-out coupled with high-performance liquid chromatography for the determination of sulfonamides in water and food.

PubMed

Han, Juan; Wang, Yun; Liu, Yan; Li, Yanfang; Lu, Yang; Yan, Yongsheng; Ni, Liang

2013-02-01

Ionic liquid-salt aqueous two-phase extraction coupled with high-performance liquid chromatography with ultraviolet detection was developed for the determination of sulfonamides in water and food samples. In the procedure, the analytes were extracted from the aqueous samples into the ionic liquid top phase in one step. Three sulfonamides, sulfamerazine, sulfamethoxazole, and sulfamethizole were selected here as model compounds for developing and evaluating the method. The effects of various experimental parameters in extraction step were studied using two optimization methods, one variable at a time and Box-Behnken design. The results showed that the amount of sulfonamides did not have effect on the extraction efficiency. Therefore, a three-level Box-Behnken experimental design with three factors, which combined the response surface modeling, was used to optimize sulfonamides extraction. Under the most favorable extraction parameters, the detection limits (S/N = 3) and quantification limits (S/N = 10) of the proposed method for the target compounds were achieved within the range of 0.15-0.3 ng/mL and 0.5-1.0 ng/mL from spiked samples, respectively, which are lower than or comparable with other reported approaches applied to the determination of the same compounds. Finally, the proposed method was successfully applied to the determination of sulfonamide compounds in different water and food samples and satisfactory recoveries of spiked target compounds in real samples were obtained.

Preliminary extraction of tannins by 1-butyl-3-methylimidazole bromide and its subsequent removal from Galla chinensis extract using macroporous resins.

PubMed

Lu, Chunxia; Luo, Xiaoling; Lu, Liliang; Li, Hongmin; Chen, Xia; Ji, Yong

2013-03-01

In recent years, ionic liquids have become increasingly attractive as 'green solvents' used in the extraction of bioactive compounds from natural plant. However, the separation of ionic liquid from the target compounds was difficult, due to their low vapour pressure and high stabilities. In our study, ionic liquid-based ultrasonic and microwave-assisted extraction was used to obtain the crude tannins, then the macroporous resin adsorption technology was further employed to purify the tannins and remove the ionic liquid from crude extract. The results showed that XDA-6 had higher separation efficiency than other tested resins, and the equilibrium experimental data were well fitted to Langmuir isotherms. Dynamic adsorption and desorption were performed on XDA-6 packed in glass columns to optimise the separation process. The optimum conditions as follows: the ratio of column height to diameter bed was 1:8, flow rate 1 BV/h (bed volume per hour), 85% ethanol was used as eluant while the elution volume was 2 BV. Under the optimised conditions, the adsorption and desoption rate of tannins in XDA-6 were 94.81 and 91.63%, respectively. The content of tannins was increased from 70.24% in Galla chinensis extract to 85.12% with a recovery of 99.06%. The result of ultra-performance liquid chromatography (UPLC)-MS/MS analysis showed that [bmim]Br could be removed from extract. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Comparison of two extraction techniques, solid-phase microextraction versus continuous liquid-liquid extraction/solvent-assisted flavor evaporation, for the analysis of flavor compounds in gueuze lambic beer.

PubMed

Thompson-Witrick, Katherine A; Rouseff, Russell L; Cadawallader, Keith R; Duncan, Susan E; Eigel, William N; Tanko, James M; O'Keefe, Sean F

2015-03-01

Lambic is a beer style that undergoes spontaneous fermentation and is traditionally produced in the Payottenland region of Belgium, a valley on the Senne River west of Brussels. This region appears to have the perfect combination of airborne microorganisms required for lambic's spontaneous fermentation. Gueuze lambic is a substyle of lambic that is made by mixing young (approximately 1 year) and old (approximately 2 to 3 years) lambics with subsequent bottle conditioning. We compared 2 extraction techniques, solid-phase microextraction (SPME) and continuous liquid-liquid extraction/solvent-assisted flavor evaporation (CCLE/SAFE), for the isolation of volatile compounds in commercially produced gueuze lambic beer. Fifty-four volatile compounds were identified and could be divided into acids (14), alcohols (12), aldehydes (3), esters (20), phenols (3), and miscellaneous (2). SPME extracted a total of 40 volatile compounds, whereas CLLE/SAFE extracted 36 volatile compounds. CLLE/SAFE extracted a greater number of acids than SPME, whereas SPME was able to isolate a greater number of esters. Neither extraction technique proved to be clearly superior and both extraction methods can be utilized for the isolation of volatile compounds found in gueuze lambic beer. © 2015 Institute of Food Technologists®

Extraction of benzene and cyclohexane using [BMIM][N(CN)2] and their equilibrium modeling

NASA Astrophysics Data System (ADS)

Ismail, Marhaina; Bustam, M. Azmi; Man, Zakaria

2017-12-01

The separation of aromatic compound from aliphatic mixture is one of the essential industrial processes for an economically green process. In order to determine the separation efficiency of ionic liquid (IL) as a solvent in the separation, the ternary diagram of liquid-liquid extraction (LLE) 1-butyl-3-methylimidazolium dicyanamide [BMIM][N(CN)2] with benzene and cyclohexane was studied at T=298.15 K and atmospheric pressure. The solute distribution coefficient and solvent selectivity derived from the equilibrium data were used to evaluate if the selected ionic liquid can be considered as potential solvent for the separation of benzene from cyclohexane. The experimental tie line data was correlated using non-random two liquid model (NRTL) and Margules model. It was found that the solute distribution coefficient is (0.4430-0.0776) and selectivity of [BMIM][N(CN)2] for benzene is (53.6-13.9). The ternary diagram showed that the selected IL can perform the separation of benzene and cyclohexane as it has extractive capacity and selectivity. Therefore, [BMIM][N(CN)2] can be considered as a potential extracting solvent for the LLE of benzene and cyclohexane.

Liquid by-products from fish canning industry as sustainable sources of ω3 lipids.

PubMed

Monteiro, Ana; Paquincha, Diogo; Martins, Florinda; Queirós, Rui P; Saraiva, Jorge A; Švarc-Gajić, Jaroslava; Nastić, Nataša; Delerue-Matos, Cristina; Carvalho, Ana P

2018-08-01

Fish canning industry generates large amounts of liquid wastes, which are discarded, after proper treatment to remove the organic load. However, alternative treatment processes may also be designed in order to target the recovery of valuable compounds; with this procedure, these wastewaters are converted into liquid by-products, becoming an additional source of revenue for the company. This study evaluated green and economically sustainable methodologies for the extraction of ω3 lipids from fish canning liquid by-products. Lipids were extracted by processes combining physical and chemical parameters (conventional and pressurized extraction processes), as well as chemical and biological parameters. Furthermore, LCA was applied to evaluate the environmental performance and costs indicators for each process. Results indicated that extraction with high hydrostatic pressure provides the highest amounts of ω3 polyunsaturated fatty acids (3331,5 mg L -1 effluent), apart from presenting the lowest environmental impact and costs. The studied procedures allow to obtain alternative, sustainable and traceable sources of ω3 lipids for further applications in food, pharmaceutical and cosmetic industries. Additionally, such approach contributes towards the organic depuration of canning liquid effluents, therefore reducing the overall waste treatment costs. Copyright © 2018 Elsevier Ltd. All rights reserved.

Genotoxicity, mutagenicity and cytotoxicity of carotenoids extracted from ionic liquid in multiples organs of Wistar rats.

PubMed

Larangeira, Paula Martins; de Rosso, Veridiana Vera; da Silva, Victor Hugo Pereira; de Moura, Carolina Foot Gomes; Ribeiro, Daniel Araki

2016-11-01

The ionic liquid or melted salt 1-Butyl-3-methylimidazolium is an alternative process to extract natural pigments, such as carotenoids. Lycopene represents 80-90% of total of carotenoids presents in tomatoes and it has been widely studied due its potent antioxidant action. The aim of this study was to evaluate genotoxicity, mutagenicity and cytotoxicity of carotenoids extracted from ionic liquid using experimental model in vivo. For this purpose, a total of 20 male Wistar rats were distributed into four groups (n=5), as follows: control group; received a corresponding amount of corn oil for 7days by intragastric gavage (i.g.), ionic liquid group, received 10mgkg -1 body weight for 7days by gavage; 10mg carotenoids group, received 10mgkg -1 bw dissolved in corn oil for 7days by gavage and 500mg carotenoids group, received 500mgkg -1 bw dissolved in corn oil for 7days by gavage. Rat liver treated with ionic liquid exhibited moderate histopathological changes randomly distributed in the parenchyma, such as cytoplasmic eosinophilia, apoptotic bodies, inflammatory infiltrate and focal necrosis. DNA damage was found in peripheral blood and liver cells of rats treated with ionic liquid or carotenoids at 500mg. An increase of micronucleated cells and 8-OhDG immunopositive cells were also detected in rats treated with carotenoids at 500mg. In summary, our results demonstrate that recommended dose for human daily intake of carotenoids extracted by ionic liquid did not induce genotoxicity, mutagenicity and cytotoxicity in multiple organs of rats. Copyright © 2016 Elsevier GmbH. All rights reserved.

[Advances of poly (ionic liquid) materials in separation science].

PubMed

Liu, Cuicui; Guo, Ting; Su, Rina; Gu, Yuchen; Deng, Qiliang

2015-11-01

Ionic liquids, as novel ionization reagents, possess beneficial characteristics including good solubility, conductivity, thermal stability, biocompatibility, low volatility and non-flammability. Ionic liquids are attracting a mass of attention of analytical chemists. Poly (ionic liquid) materials have common performances of ionic liquids and polymers, and have been successfully applied in separation science area. In this paper, we discuss the interaction mechanisms between the poly(ionic liquid) materials and analytes including hydrophobic/hydrophilic interactions, hydrogen bond, ion exchange, π-π stacking and electrostatic interactions, and summarize the application advances of the poly(ionic liquid) materials in solid phase extraction, chromatographic separation and capillary electrophoresis. At last, we describe the future prospect of poly(ionic liquid) materials.

CTEPP STANDARD OPERATING PROCEDURE FOR EXTRACTING AND PREPARING LIQUID FOOD SAMPLES FOR ANALYSIS OF PERSISTENT ORGANIC POLLUTANTS (SOP-5.19)

EPA Science Inventory

This SOP describes the procedures for homogenizing, extracting, and concentrating liquid food samples for neutral persistent organic pollutants such as organochlorine compounds, organophosphate compounds, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and phenols.

Isolation of Biliverdin Ixa, as Its Dimethyl Ester, from Emu Eggshells

ERIC Educational Resources Information Center

Halepas, Steven; Hamchand, Randy; Lindeyer, Samuel E. D.; Bru¨ckner, Christian

2017-01-01

A laboratory experiment is described that extracts the tetrapyrrolic teal-colored biliverdin IXa, as its dimethyl ester, from commercially available emu eggshells. The extraction of ~10 mg samples of biliverdin is simple and requires two 3 h lab periods: A two-step acid digestion and liquid-liquid extraction, followed by short silica gel flash…

Determination of Low Level Alpha and Beta Emitters Using Liquid-Liquid Extraction and a Liquid Scintillation Spectrometer

NASA Astrophysics Data System (ADS)

Yu, Yu-Fu; BjØRnstad, H. E.; Salbu, B.

Two radiochemical procedures for determination of low level strontium-90 and plutonium-239+240 in environmental and biological materials using combined selective solvent extraction with low level liquid scintillation counting have been presented. Y-90, the daughter nuclide of Sr-90, and Pu-239+240 are selectively extracted from nitric acid solution into 5% di(-2ethylhexyl)phosphoric acid (HDEHP) in toluene and the radionuclides of interest in organic phase are counted with an ultra low level scintillation counter "Quantulus". The lower detection limits for Sr-90 and Pu-239+240 are estimated to be 20 mBq and 0.3 mBq respectively. The developed procedures have been tested for soma environmental and biological samples and the preminarly results show that they are more simple and time-saving than traditional methods.

Dynamic ultrasonic nebulisation extraction coupled with headspace ionic liquid-based single-drop microextraction for the analysis of the essential oil in Forsythia suspensa.

PubMed

Yang, Jinjuan; Wei, Hongmin; Teng, Xiane; Zhang, Hanqi; Shi, Yuhua

2014-01-01

Ionic liquids have attracted much attention as an extraction solvent instead of traditional organic solvent in single-drop microextraction. However, non-volatile ionic liquids are difficult to couple with gas chromatography. Thus, the following injection system for the determination of organic compounds is described. To establish an environmentally friendly, simple, and effective extraction method for preparation and analysis of the essential oil from aromatic plants. The dynamic ultrasonic nebulisation extraction was coupled with headspace ionic liquid-based single-drop microextraction(UNE-HS/IL/SDME)for the extraction of essential oils from Forsythia suspense fruits. After 13 min of extraction for 50 mg sample, the extracts in ionic liquid were evaporated rapidly in the gas chromatography injector through a thermal desorption unit (5 s). The traditional extraction method was carried out for comparative study. The optimum conditions were: 3 μL of 1-methyl-3-octylimidazolium hexafluorophosphate was selected as the extraction solvent, the sample amount was 50 mg, the flow rate of purging gas was 200 mL/min, the extraction time was 13 min, the injection volume was 2 μL, and the thermal desorption temperature and time were 240 °C and 5 s respectively. Comparing with hydrodistillation (HD), the proposed method was environment friendly and efficient. The proposed method is environmentally friendly, time saving, with high efficiency and low consumption. It would extend the application range of the HS/SDME and would be useful especially for aromatic plants analysis. Copyright © 2013 John Wiley & Sons, Ltd.

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.

PubMed

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 .

Continuous-flow liquid microjunction surface sampling probe connected on-line with high-performance liquid chromatography/mass spectrometry for spatially resolved analysis of small molecules and proteins.

PubMed

Van Berkel, Gary J; Kertesz, Vilmos

2013-06-30

A continuous-flow liquid microjunction surface sampling probe extracts soluble material from surfaces for direct ionization and detection by mass spectrometry. Demonstrated here is the on-line coupling of such a probe with high-performance liquid chromatography/mass spectrometry (HPLC/MS) enabling extraction, separation and detection of small molecules and proteins from surfaces in a spatially resolved (~0.5 mm diameter spots) manner. A continuous-flow liquid microjunction surface sampling probe was connected to a six-port, two-position valve for extract collection and injection to an HPLC column. A QTRAP® 5500 hybrid triple quadrupole linear ion trap equipped with a Turbo V™ ion source operated in positive electrospray ionization (ESI) mode was used for all experiments. The system operation was tested with the extraction, separation and detection of propranolol and associated metabolites from drug dosed tissues, caffeine from a coffee bean, cocaine from paper currency, and proteins from dried sheep blood spots on paper. Confirmed in the tissue were the parent drug and two different hydroxypropranolol glucuronides. The mass spectrometric response for these compounds from different locations in the liver showed an increase with increasing extraction time (5, 20 and 40 s). For on-line separation and detection/identification of extracted proteins from dried sheep blood spots, two major protein peaks dominated the chromatogram and could be correlated with the expected masses for the hemoglobin α and β chains. Spatially resolved sampling, separation, and detection of small molecules and proteins from surfaces can be accomplished using a continuous-flow liquid microjunction surface sampling probe coupled on-line with HPLC/MS detection. Published in 2013. This article is a U.S. Government work and is in the public domain in the USA.

Multiclass method for the determination of pharmaceuticals and personal care products in compost from sewage sludge using ultrasound and salt-assisted liquid-liquid extraction followed by ultrahigh performance liquid chromatography-tandem mass spectrometry analysis.

PubMed

Luque-Muñoz, A; Vílchez, J L; Zafra-Gómez, A

2017-07-21

An analytical method for the analysis of 16 pharmaceuticals and personal care products in compost from sewage sludge is successfully validated. Ultrasound assisted extraction with a mixture of acetonitrile:ethyl acetate (1:1, v/v) containing 10% (v/v) of acetic acid was carried out. Two cycles of extraction of 10min were applied. A clean-up of the extracts using salt-assisted liquid-liquid extraction (SALLE) was also included. Experimental design was used for the optimization of the main parameters involved in the extraction and cleaned-up steps. The chromatographic separation was carried out by ultrahigh performance liquid chromatography using a mobile phase gradient mixture of a 13mM buffer ammonium formate solution (pH 9.25) (solvent A) and methanol (solvent B). An ACQUITY UPLC ® BEH C18 column (1.7μm; 2.1×50mm) column was used. Analytes were separated in less than 11min. The compounds were detected and quantified using single reaction monitoring electrospray tandem mass spectrometry. The limits of detection calculated ranged from 0.5 to 4ngg -1 d.w., and the limits of quantification from 2 to 13ngg -1 d.w. Recoveries from 93% to 111%, with relative standar deviations lower than 11% in all cases, were obtained. The method was applied to natural compost samples. High concentrations of some analytes were found. Ketoprofen (510ngg -1 d.w.), methylparaben (240ngg -1 d.w.), diclofenac (175ngg -1 d.w.) and flufenamic acid (128ngg -1 d.w.) were the most abundant. Copyright © 2017 Elsevier B.V. All rights reserved.

In situ ionic liquid dispersive liquid-liquid microextraction and direct microvial insert thermal desorption for gas chromatographic determination of bisphenol compounds.

PubMed

Cacho, Juan Ignacio; Campillo, Natalia; Viñas, Pilar; Hernández-Córdoba, Manuel

2016-01-01

A new procedure based on direct insert microvial thermal desorption injection allows the direct analysis of ionic liquid extracts by gas chromatography and mass spectrometry (GC-MS). For this purpose, an in situ ionic liquid dispersive liquid-liquid microextraction (in situ IL DLLME) has been developed for the quantification of bisphenol A (BPA), bisphenol Z (BPZ) and bisphenol F (BPF). Different parameters affecting the extraction efficiency of the microextraction technique and the thermal desorption step were studied. The optimized procedure, determining the analytes as acetyl derivatives, provided detection limits of 26, 18 and 19 ng L(-1) for BPA, BPZ and BPF, respectively. The release of the three analytes from plastic containers was monitored using this newly developed analytical method. Analysis of the migration test solutions for 15 different plastic containers in daily use identified the presence of the analytes at concentrations ranging between 0.07 and 37 μg L(-1) in six of the samples studied, BPA being the most commonly found and at higher concentrations than the other analytes.

Organocatalytic, Diastereo- and Enantioselective Synthesis of Nonsymmetric cis-Stilbene Diamines: A Platform for the Preparation of Single-Enantiomer cis-Imidazolines for Protein–Protein Inhibition

PubMed Central

2015-01-01

The finding by scientists at Hoffmann-La Roche that cis-imidazolines could disrupt the protein–protein interaction between p53 and MDM2, thereby inducing apoptosis in cancer cells, raised considerable interest in this scaffold over the past decade. Initial routes to these small molecules (i.e., Nutlin-3) provided only the racemic form, with enantiomers being enriched by chromatographic separation using high-pressure liquid chromatography (HPLC) and a chiral stationary phase. Reported here is the first application of an enantioselective aza-Henry approach to nonsymmetric cis-stilbene diamines and cis-imidazolines. Two novel mono(amidine) organocatalysts (MAM) were discovered to provide high levels of enantioselection (>95% ee) across a broad range of substrate combinations. Furthermore, the versatility of the aza-Henry strategy for preparing nonsymmetric cis-imidazolines is illustrated by a comparison of the roles of aryl nitromethane and aryl aldimine in the key step, which revealed unique substrate electronic effects providing direction for aza-Henry substrate–catalyst matching. This method was used to prepare highly substituted cis-4,5-diaryl imidazolines that project unique aromatic rings, and these were evaluated for MDM2-p53 inhibition in a fluorescence polarization assay. The diversification of access to cis-stilbene diamine-derived imidazolines provided by this platform should streamline their further development as chemical tools for disrupting protein–protein interactions. PMID:25017623

Enantiomeric separation of 2-arylpropionic acid nonsteroidal anti-inflammatory drugs by HPLC with hydroxypropyl-beta-cyclodextrin as chiral mobile phase additive.

PubMed

Ye, Jincui; Yu, Wenying; Chen, Guosheng; Shen, Zhengrong; Zeng, Su

2010-08-01

The enantio-separations of eight 2-arylpropionic acid nonsteroidal anti-inflammatory drugs (2-APA NSAIDs) were established using reversed-phase high-performance liquid chromatography with hydroxypropyl-beta-cyclodextrin (HP-beta-CD) as chiral mobile phase additive for studying the stereoselective skin permeation of suprofen, ketoprofen, naproxen, indoprofen, fenoprofen, furbiprofen, ibuprofen and carprofen. The effects of the mobile phase composition, concentration of HP-beta-CD and column temperature on retention and enantioselective separation were investigated. With 2-APA NSAIDs as acidic analytes, the retention times and resolutions of the enantiomers were strongly related to the pH of the mobile phase. In addition, both the concentration of HP-beta-CD and temperature had a great effect on retention time, but only a slight or almost no effect on resolutions of the analytes. Enantioseparations were achieved on a Shimpack CLC-ODS (150 x 4.6 mm i.d., 5 microm) column. The mobile phase was a mixture of methanol and phosphate buffer (pH 4.0-5.5, 20 mM) containing 25 mM HP-beta-CD. This method was flexible, simple and economically advantageous over the use of chiral stationary phase, and was successfully applied to the enantioselective determination of the racemic 2-APA NSAIDs in an enantioselective skin permeation study.

Reactive extraction at liquid-liquid systems

NASA Astrophysics Data System (ADS)

Wieszczycka, Karolina

2018-01-01

The chapter summarizes the state of knowledge about a metal transport in two-phase system. The first part of this review focuses on the distribution law and main factors determination in classical solvent extraction (solubility and polarity of the solute, as well as inter- and intramolecules interaction. Next part of the chapter is devoted to the reactive solvent extraction and the molecular modeling requiring knowledge on type of extractants, complexation mechanisms, metals ions speciation and oxidation during complexes forming, and other parameters that enable to understand the extraction process. Also the kinetic data that is needed for proper modeling, simulation and design of processes needed for critical separations are discussed. Extraction at liquid-solid system using solvent impregnated resins is partially identical as in the case of the corresponding solvent extraction, therefore this subject was also presented in all aspects of separation process (equilibrium, mechanism, kinetics).

Thiolene and SIFEL-based Microfluidic Platforms for Liquid-Liquid Extraction

PubMed Central

Goyal, Sachit; Desai, Amit V.; Lewis, Robert W.; Ranganathan, David R.; Li, Hairong; Zeng, Dexing; Reichert, David E.; Kenis, Paul J.A.

2014-01-01

Microfluidic platforms provide several advantages for liquid-liquid extraction (LLE) processes over conventional methods, for example with respect to lower consumption of solvents and enhanced extraction efficiencies due to the inherent shorter diffusional distances. Here, we report the development of polymer-based parallel-flow microfluidic platforms for LLE. To date, parallel-flow microfluidic platforms have predominantly been made out of silicon or glass due to their compatibility with most organic solvents used for LLE. Fabrication of silicon and glass-based LLE platforms typically requires extensive use of photolithography, plasma or laser-based etching, high temperature (anodic) bonding, and/or wet etching with KOH or HF solutions. In contrast, polymeric microfluidic platforms can be fabricated using less involved processes, typically photolithography in combination with replica molding, hot embossing, and/or bonding at much lower temperatures. Here we report the fabrication and testing of microfluidic LLE platforms comprised of thiolene or a perfluoropolyether-based material, SIFEL, where the choice of materials was mainly guided by the need for solvent compatibility and fabrication amenability. Suitable designs for polymer-based LLE platforms that maximize extraction efficiencies within the constraints of the fabrication methods and feasible operational conditions were obtained using analytical modeling. To optimize the performance of the polymer-based LLE platforms, we systematically studied the effect of surface functionalization and of microstructures on the stability of the liquid-liquid interface and on the ability to separate the phases. As demonstrative examples, we report (i) a thiolene-based platform to determine the lipophilicity of caffeine, and (ii) a SIFEL-based platform to extract radioactive copper from an acidic aqueous solution. PMID:25246730

Multi-residue method for determination of 58 pesticides, pharmaceuticals and personal care products in water using solvent demulsification dispersive liquid-liquid microextraction combined with liquid chromatography-tandem mass spectrometry.

PubMed

Caldas, Sergiane Souza; Rombaldi, Caroline; Arias, Jean Lucas de Oliveira; Marube, Liziane Cardoso; Primel, Ednei Gilberto

2016-01-01

A rapid and efficient sample pretreatment using solvent-based de-emulsification dispersive liquid-liquid microextraction (SD-DLLME) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was studied for the extraction of 58 pharmaceuticals and personal care products (PPCPs) and pesticides from water samples. Type and volume of extraction and disperser solvents, pH, salt addition, amount of salt and type of demulsification solvent were evaluated. Limits of quantification (LOQ) in the range from 0.0125 to 1.25 µg L(-1) were reached, and linearity was in the range from the LOQ of each compound to 25 μg L(-1). Recoveries ranged from 60% to 120% for 84% of the compounds, with relative standard deviations lower than 29%. The proposed method demonstrated, for the first time, that sample preparation by SD-DLLME with determination by LC-MS/MS can be successfully used for the simultaneous extraction of 32 pesticides and 26 PPCPs from water samples. The entire procedure, including the extraction of 58 organic compounds from the aqueous sample solution and the breaking up of the emulsion after extraction with water, rather than with an organic solvent, was environmentally friendly. In addition, this technique was less expensive and faster than traditional techniques. Finally, the analytical method under study was successfully applied to the analysis of all 58 pesticides and PPCPs in surface water samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Simultaneous determination of nicotine and cotinine in serum using high-performance liquid chromatography with fluorometric detection and postcolumn UV-photoirradiation system.

PubMed

Yasuda, Makoto; Ota, Tatsuhiro; Morikawa, Atsushi; Mawatari, Ken-ichi; Fukuuchi, Tomoko; Yamaoka, Noriko; Kaneko, Kiyoko; Nakagomi, Kazuya

2013-09-01

A simple and rapid method for the simultaneous determination of serum nicotine and cotinine using high-performance liquid chromatography (HPLC)-fluorometric detection with a postcolumn ultraviolet-photoirradiation system was developed. Analytes were extracted from alkalinized human serum via liquid-liquid extraction using chloroform. The organic phase was back-extracted with the acidified aqueous phase, and the analytes were directly injected into an ion-pair reversed-phase HPLC system. 6-Aminoquinoline was used as an internal standard. Nicotine, cotinine, and 6-aminoquinoline were separated within 14min. The extraction efficiency of nicotine and cotinine was greater than 91%. The linear range was 0.30-1000ng for nicotine and 0.06-1000ng for cotinine. In serum samples from smokers, the concentrations of nicotine and cotinine were 8-15ng/mL and 156-372ng/mL, respectively. Copyright © 2013 Elsevier B.V. All rights reserved.

On the Extraction of Aromatic Compounds from Hydrocarbons by Imidazolium Ionic Liquids

PubMed Central

Cassol, Cláudia C.; Umpierre, Alexandre P.; Ebeling, Günter; Ferrera, Bauer; Chiaro, Sandra S. X.; Dupont, Jairton

2007-01-01

The liquid-liquid equilibrium for the ternary system formed by n-octane and aromatic (alkylbenzenes) and heteroaromatic compounds (nitrogen and sulfur containing heterocyles) and 1-alkyl-3-methylimidazolium ionic liquids (ILs) associated with various anions has been investigated. The selectivity on the extraction of a specific aromatic compound is influenced by anion volume, hydrogen bond strength between the anion and the imidazolium cation and the length of the 1-methyl-3-alkylimidazolium alkyl side chain. The interaction of alkylbenzenes and sulfur heterocyles with the IL is preferentially through CH-π hydrogen bonds and the quantity of these aromatics in the IL phase decreases with the increase of the steric hindrance imposed by the substituents on the aromatic nucleus. In the case of nitrogen heterocycles the interaction occurs preferentially through N(heteroaromatic)-H(imidazolium) hydrogen bonds and the extraction process is largely controlled by the nitrogen heterocycle pKa. Competitive extraction experiments suggest that benzene, pyridine and dibenzothiophene do not compete for the same hydrogen bond sites of the IL.

Apparatus and methods for monitoring the concentrations of hazardous airborne substances, especially lead

DOEpatents

Zaromb, Solomon

2004-07-13

Air is sampled at a rate in excess of 100 L/min, preferably at 200-300 L/min, so as to collect therefrom a substantial fraction, i.e., at least 20%, preferably 60-100%, of airborne particulates. A substance of interest (analyte), such as lead, is rapidly solubilized from the the collected particulates into a sample of liquid extractant, and the concentration of the analyte in the extractant sample is determined. The high-rate air sampling and particulate collection may be effected with a high-throughput filter cartridge or with a recently developed portable high-throughput liquid-absorption air sampler. Rapid solubilization of lead is achieved by a liquid extractant comprising 0.1-1 M of acetic acid or acetate, preferably at a pH of 5 or less and preferably with inclusion of 1-10% of hydrogen peroxide. Rapid determination of the lead content in the liquid extractant may be effected with a colorimetric or an electroanalytical analyzer.

The Effect of Protein Restriction in the In Vitro Metabolism of Albendazole in Rats.

PubMed

Belaz, Kátia Roberta A; de O Cardoso, Josiane; da Silva, Carlos Alberto; Oliveira, Regina V

2015-01-01

This work presents an in vitro investigation of the effect of protein restriction on the metabolism of albendazole (ABZ). This study was conducted using liver microsomal fractions obtained from Wistar rats. For the quantitative analysis, a multidimensional High Performance Liquid Chromatography (2D HPLC) method was fully validated for the determination of the ABZ metabolites: albendazole sulfoxide, albendazole sulfone and albendazole 2-aminesulfone. The target compounds were directly extracted using a C8-RAM-BSA column (5.0x0.46 cm i.d.) and analyzed on a chromatographic chiral column containing amylose tris(3,5-dimethylphenylcarbamate) (150x4.6 mm i.d.). The in vitro biotransformation results showed that the protein restriction influenced the oxidative metabolism of ABZ. The production of R-(+)-ABZ-SO (1309 nmol/L) and S-(-)-ABZ-SO (1456 nmol/L) was higher in the control animals than in the animals fed with a diet containing 6% protein, which produced 778.7 nmol/L and 709.5 nmol/L for R-(+) and S-(-)-ABZ-SO enantiomers, respectively. These results were statistically inspected by Student´s t test and the results showed a significant difference between the two means (p<0.05). Moreover, the production of ABZ-SO enantiomers was enantioselective where the S-(-)-ABZ-SO was formed in greater amounts than the R-(+)-ABZ-SO in control animals (p=0.0231). However, the enantioselectivity was not observed when the in vitro biotransformation of ABZ was conducted using the microsomal fractions obtained from protein restriction animals (p>0.05). Furthermore, animal nutritional condition could affect the pattern of ABZ sulphoxidation indicating that the protein nutrition affect primarily the formation of R-(+)-ABZSO and S-(-)-ABZ-SO enantiomers.

Methylxanthines: properties and determination in various objects

NASA Astrophysics Data System (ADS)

Andreeva, Elena Yu; Dmitrienko, Stanislava G.; Zolotov, Yurii A.

2012-05-01

Published data on the properties and determination of caffeine, theophylline, theobromine and some other methylxanthines in various objects are surveyed and described systematically. Different sample preparation procedures such as liquid extraction from solid matrices and liquid-liquid, supercritical fluid and solid-phase extraction are compared. The key methods of analysis including chromatography, electrophoresis, spectrometry and electrochemical methods are discussed. Examples of methylxanthine determination in plants, food products, energy beverages, pharmaceuticals, biological fluids and natural and waste waters are given. The bibliography includes 393 references.

Chemical properties of the transactinide elements studied inliquid phase with SISAK

DOE Office of Scientific and Technical Information (OSTI.GOV)

Omtvedt, J.P.; Alstad, J.; Bjornstad, T.

2007-05-01

This article starts with a review of the current SISAKliquid-liquid extraction system, as used after the physical preseparatorBGS at LBNL for chemical studies of transactinide elements. Emphasis willbe on new additions and developments. Then the possibilities offered bythe new TASCA separator at GSI and the use of actinide targets at bothGSI and LBNL are discussed with respect to future SISAK transactinideexperiments. Finally, current and future liquid-liquid extraction systemsfor studying elements Rf up to Hs are discussed.

Sample preparation combined with electroanalysis to improve simultaneous determination of antibiotics in animal derived food samples.

PubMed

da Silva, Wesley Pereira; de Oliveira, Luiz Henrique; Santos, André Luiz Dos; Ferreira, Valdir Souza; Trindade, Magno Aparecido Gonçalves

2018-06-01

A procedure based on liquid-liquid extraction (LLE) and phase separation using magnetically stirred salt-induced high-temperature liquid-liquid extraction (PS-MSSI-HT-LLE) was developed to extract and pre-concentrate ciprofloxacin (CIPRO) and enrofloxacin (ENRO) from animal food samples before electroanalysis. Firstly, simple LLE was used to extract the fluoroquinolones (FQs) from animal food samples, in which dilution was performed to reduce interference effects to below a tolerable threshold. Then, adapted PS-MSSI-HT-LLE protocols allowed re-extraction and further pre-concentration of target analytes in the diluted acid samples for simultaneous electrochemical quantification at low concentration levels. To improve the peak separation, in simultaneous detection, a baseline-corrected second-order derivative approach was processed. These approaches allowed quantification of target FQs from animal food samples spiked at levels of 0.80 to 2.00 µmol L -1 in chicken meat, with recovery values always higher than 80.5%, as well as in milk samples spiked at 4.00 µmol L -1 , with recovery values close to 70.0%. Copyright © 2018 Elsevier Ltd. All rights reserved.

40 CFR 68.3 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... for reasons of national security.” Condensate means hydrocarbon liquid separated from natural gas that... processing plant (gas plant) means any processing site engaged in the extraction of natural gas liquids from field gas, fractionation of mixed natural gas liquids to natural gas products, or both, classified as...

40 CFR 68.3 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... for reasons of national security.” Condensate means hydrocarbon liquid separated from natural gas that... processing plant (gas plant) means any processing site engaged in the extraction of natural gas liquids from field gas, fractionation of mixed natural gas liquids to natural gas products, or both, classified as...

40 CFR 68.3 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... for reasons of national security.” Condensate means hydrocarbon liquid separated from natural gas that... processing plant (gas plant) means any processing site engaged in the extraction of natural gas liquids from field gas, fractionation of mixed natural gas liquids to natural gas products, or both, classified as...

40 CFR 68.3 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... for reasons of national security.” Condensate means hydrocarbon liquid separated from natural gas that... processing plant (gas plant) means any processing site engaged in the extraction of natural gas liquids from field gas, fractionation of mixed natural gas liquids to natural gas products, or both, classified as...

40 CFR 68.3 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... for reasons of national security.” Condensate means hydrocarbon liquid separated from natural gas that... processing plant (gas plant) means any processing site engaged in the extraction of natural gas liquids from field gas, fractionation of mixed natural gas liquids to natural gas products, or both, classified as...

Analysis of potential migrants from plastic materials in milk by liquid chromatography-mass spectrometry with liquid-liquid extraction and low-temperature purification.

PubMed

Bodai, Zsolt; Szabó, Bálint Sámuel; Novák, Márton; Hámori, Susanne; Nyiri, Zoltán; Rikker, Tamás; Eke, Zsuzsanna

2014-10-15

A simple and fast analytical method was developed for the determination of six UV stabilizers (Cyasorb UV-1164, Tinuvin P, Tinuvin 234, Tinuvin 326, Tinuvin 327, and Tinuvin 1577) and five antioxidants (Irgafos 168, Irganox 1010, Irganox 3114, Irganox 3790, and Irganox 565) in milk. For sample preparation liquid-liquid extraction with low-temperature purification combined with centrifugation was used to remove fats, proteins, and sugars. After the cleanup step, the sample was analyzed with high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). External standard and matrix calibrations were tested. External calibration proved to be acceptable for Tinuvin P, Tinuvin 234, Tinuvin 326, Tinuvin 327, Irganox 3114, and Irganox 3790. The method was successfully validated with matrix calibration for all compounds. Method detection limits were between 0.25 and 10 μg/kg. Accuracies ranged from 93 to 109%, and intraday precisions were <13%.

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

PubMed

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.

Optimization of ultrasound-assisted hydroalcoholic extraction of phenolic compounds from walnut leaves using response surface methodology.

PubMed

Nour, Violeta; Trandafir, Ion; Cosmulescu, Sina

2016-10-01

Context Walnut leaves are highly appreciated for their pharmacological effects and therapeutic properties which are mainly attributed to their high content of phenolic compounds. Objective This study optimizes ultrasound assisted hydroalcoholic extraction (UAE) of phenolic compounds from dried walnut leaves by the maximization of total phenolics content (TPC) and total flavanoids content (TFC) of the extracts. Materials and methods Optimal conditions with regard to ethanol concentration (X1: 12.17-95.83% v/v), extraction time (X2: 8.17-91.83 min) and liquid-to-solid ratio (X3: 4.96-25.04 v/w) were identified using central composite design combined with response surface methodology. A high-performance liquid chromatography method with diode-array detection was used to quantify phenolic acids (gallic, vanillic, chlorogenic, caffeic, syringic, p-coumaric, ferulic, sinapic, salicylic, ellagic and trans-cinnamic), flavonoids (catechin, epicatechin, rutin, myricetin and quercetin) and juglone in the extracts. Results Liquid-to-solid ratio and ethanol concentration proved to be the primary factors affecting the extraction efficiency. The maximum predicted TPC, under the optimized conditions (61% ethanol concentration, 51.28 min extraction time and 4.96 v/w liquid-to-solid ratio) was 10125.4 mg gallic acid equivalents per liter while maximum TFC (2925 mg quercetin equivalents per liter) occurred at 67.83% ethanol concentration, 4.96 v/w liquid-to-solid ratio and 49.37 min extraction time. High significant correlations were found between antioxidant activity and both TPC (R(2 )=( )0.81) and TFC (R(2 )=( )0.78). Discussion and conclusion Extracts very rich in polyphenols could be obtained from walnut leaves by using UAE, aimed at preparing dietary supplements, nutraceuticals or functional food ingredients.

Capabilities and limitations of dispersive liquid-liquid microextraction with solidification of floating organic drop for the extraction of organic pollutants from water samples.

PubMed

Vera-Avila, Luz E; Rojo-Portillo, Tania; Covarrubias-Herrera, Rosario; Peña-Alvarez, Araceli

2013-12-17

Dispersive liquid-liquid microextraction with solidification of floating organic drop (DLLME-SFO) is one of the most interesting sample preparation techniques developed in recent years. Although several applications have been reported, the potentiality and limitations of this simple and rapid extraction technique have not been made sufficiently explicit. In this work, the extraction efficiency of DLLME-SFO for pollutants from different chemical families was determined. Studied compounds include: 10 polycyclic aromatic hydrocarbons, 5 pesticides (chlorophenoxy herbicides and DDT), 8 phenols and 6 sulfonamides, thus, covering a large range of polarity and hydrophobicity (LogKow 0-7, overall). After optimization of extraction conditions using 1-dodecanol as extractant, the procedure was applied for extraction of each family from 10-mL spiked water samples, only adjusting sample pH as required. Absolute recoveries for pollutants with LogKow 3-7 were >70% and recovery values within this group (18 compounds) were independent of structure or hydrophobicity; the precision of recovery was very acceptable (RSD<12%) and linear behavior was observed in the studied concentration range (r(2)>0.995). Extraction recoveries for pollutants with LogKow 1.46-2.8 were in the range 13-62%, directly depending on individual LogKow values; however, good linearity (r(2)>0.993) and precision (RSD<6.5%) were also demonstrated for these polar solutes, despite recovery level. DLLME-SFO with 1-dodecanol completely failed for extraction of compounds with LogKow≤1 (sulfa drugs), other more polar extraction solvents (ionic liquids) should be explored for highly hydrophilic pollutants. Copyright © 2013 Elsevier B.V. All rights reserved.

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

PubMed

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.

Magnetic solid-phase extraction based on magnetic multiwalled carbon nanotubes for the simultaneous enantiomeric analysis of five β-blockers in the environmental samples by chiral liquid chromatography coupled with tandem mass spectrometry.

PubMed

Wang, Zhaokun; Zhang, Xue; Jiang, Shenmeng; Guo, Xingjie

2018-04-01

In this work, the magnetic multiwalled carbon nanotubes (Mag-MWCNTs) were prepared by self-assembly method and characterized by scanning electron microscopy, X-ray powder diffraction, energy dispersive X-ray and vibrating sample magnetometer. Then, these synthetic Mag-MWCNTs were used as sorbents to extract five β-blockers (atenolol, metoprolol, esmolol, pindolol and arotinolol) by magnetic solid-phase extraction. The target analytes adsorbed on Mag-MWCNTs were eluted and determined on a chiral α-acid glycoprotein column coupled with a triple quadrupole mass spectrometry. Eventually, the proposed method was applied to the analysis of the enantiomeric composition of the studied β-blockers in three environmental samples, including river water, influent wastewater and effluent wastewater. Method detection and quantification limits for all enantiomers were in the range of 0.50-1.45 and 1.63-3.75ng/L, respectively. Satisfactory recovery (82.9-95.6%), good intra-day precision (RSD 0.4-10.4%) and inter-day precision (RSD 2.9-7.4%) were also obtained. With numerous advantages such as simplicity of operation, rapidity and high enrichment factor, the newly developed method has potential to assess the enantioselectivity of chiral drugs in ecotoxicity and biodegradation processes, which is also a new expanded application of Mag-MWCNTs in the environmental analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

Process for removing sulfate anions from waste water

DOEpatents

Nilsen, David N.; Galvan, Gloria J.; Hundley, Gary L.; Wright, John B.

1997-01-01

A liquid emulsion membrane process for removing sulfate anions from waste water is disclosed. The liquid emulsion membrane process includes the steps of: (a) providing a liquid emulsion formed from an aqueous strip solution and an organic phase that contains an extractant capable of removing sulfate anions from waste water; (b) dispersing the liquid emulsion in globule form into a quantity of waste water containing sulfate anions to allow the organic phase in each globule of the emulsion to extract and absorb sulfate anions from the waste water and (c) separating the emulsion including its organic phase and absorbed sulfate anions from the waste water to provide waste water containing substantially no sulfate anions.

Chirality in adsorption on solid surfaces.

PubMed

Zaera, Francisco

2017-12-07

In the present review we survey the main advances made in recent years on the understanding of chemical chirality at solid surfaces. Chirality is an important topic, made particularly relevant by the homochiral nature of the biochemistry of life on Earth, and many chiral chemical reactions involve solid surfaces. Here we start our discussion with a description of surface chirality and of the different ways that chirality can be bestowed on solid surfaces. We then expand on the studies carried out to date to understand the adsorption of chiral compounds at a molecular level. We summarize the work published on the adsorption of pure enantiomers, of enantiomeric mixtures, and of prochiral molecules on chiral and achiral model surfaces, especially on well-defined metal single crystals but also on other flat substrates such as highly ordered pyrolytic graphite. Several phenomena are identified, including surface reconstruction and chiral imprinting upon adsorption of chiral agents, and the enhancement or suppression of enantioselectivity seen in some cases upon adsorption of enantiomixtures of chiral compounds. The possibility of enhancing the enantiopurity of adsorbed layers upon the addition of chiral seeds and the so-called "sergeants and soldiers" phenomenon are presented. Examples are provided where the chiral behavior has been associated with either thermodynamic or kinetic driving forces. Two main approaches to the creation of enantioselective surface sites are discussed, namely, via the formation of supramolecular chiral ensembles made out of small chiral adsorbates, and by adsorption of more complex chiral molecules capable of providing suitable chiral environments for reactants by themselves, via the formation of individual adsorbate:modifier adducts on the surface. Finally, a discussion is offered on the additional effects generated by the presence of the liquid phase often required in practical applications such as enantioselective crystallization, chiral chromatography, and enantioselective catalysis.

Enantioselective biodegradation of the pyrethroid (±)-lambda-cyhalothrin by marine-derived fungi.

PubMed

Birolli, Willian G; Vacondio, Bruna; Alvarenga, Natália; Seleghim, Mirna H R; Porto, André L M

2018-04-01

The contamination of agricultural lands by pesticides is a serious environmental issue. Consequently, the development of bioremediation methods for different active ingredients, such as pyrethroids, is essential. In this study, the enantioselective biodegradation of (±)-lambda-cyhalothrin ((±)-LC) by marine-derived fungi was studied. Experiments were performed with different fungi strains (Aspergillus sp. CBMAI 1829, Acremonium sp. CBMAI 1676, Microsphaeropsis sp. CBMAI 1675 and Westerdykella sp. CBMAI 1679) in 3% malt liquid medium with 100 mg L -1 of (±)-LC. All strains biodegraded this insecticide and the residual concentrations of (±)-LC (79.2-55.2 mg L -1 , i.e., 20.8-44.8% biodegradation), their enantiomeric excesses (2-42% ee) and the 3-phenoxybenzoic acid (PBAc) concentrations (0.0-4.1 mg L -1 ) were determined. In experiments for 28 days of biodegradation in the absence and presence of artificial seawater (ASW) with the most efficient strain Aspergillus sp. CBMAI 1829, increasing concentrations of PBAc with (0.0-4.8 mg L -1 ) and without ASW (0.0-15.3 mg L -1 ) were observed. In addition, a partial biodegradation pathway was proposed. All the evaluated strains biodegraded preferentially the (1R,3R,αS)-gamma-cyhalothrin enantiomer. Therefore, marine-derived fungi enantioselectively biodegraded (±)-LC and can be applied in future studies for bioremediation of contaminated areas. This enantioselective biodegradation indicates that the employment of the most active enantiomer GC as insecticide not only enable the use of a lower amount of pesticide, but also a more easily biodegradable product, reducing the possibility of environmental contamination. Copyright © 2018 Elsevier Ltd. All rights reserved.

Determination of ketamine and its main metabolites by liquid chromatography coupled to tandem mass spectrometry in pig plasma: Comparison of extraction methods.

PubMed

Ramiole, Cindy; D'Hayer, Benoit; Boudy, Vincent; Legagneux, Josette; Fonsart, Julien; Houzé, Pascal

2017-11-30

A rapid, sensitive and specific liquid chromatography coupled to tandem mass spectrometry method was developed for the simultaneous quantification pig plasma of ketamine and its two principal metabolites, norketamine and dehydronorketamine. Three extraction procoles were assessed including acetonitrile precipitation, Oase™ microplate extraction, and liquid-liquid extraction. Oase™ microplate extraction induced no significant matrix effect, important signal/noise ratio and good recoveries, ranging from 82 to 87% for the considered compounds. Using this extraction procedure, the assay was linear in the dynamic range 10-3000ng/mL (R 2 >0.99) regardless of the analytes. Intra- and inter-day accuracies were less than 12% for all compounds and intra- and inter-day precisions expressed as RSD were within <9.9%. Samples were stable in different storage conditions. High ketamine, norketamine and dehydronorketamine concentrations up to 15,000ng/mL can be determined with good precision using appropriate sample dilution. The assay was successfully applied to pig plasma samples to determine the pharmacokinetics of ketamine and the consecutive metabolites after buccal administration of a 4mg/kg ketamine base solutions. Copyright © 2017 Elsevier B.V. All rights reserved.

Matrix effect on the determination of synthetic corticosteroids and diuretics by liquid chromatography-tandem mass spectrometry

NASA Astrophysics Data System (ADS)

Dikunets, M. A.; Appolonova, S. A.; Rodchenkov, G. M.

2009-04-01

This work presents a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) procedure for selective and reliable screening of corticosteroids and diuretics in human urine. Sample preparation included the extraction, evaporation of the organic extract under nitrogen, and solution of the dry residue. The extract was analyzed by HPLC combined with tandem mass spectrometry using electro-spraying ionization at atmospheric pressure with negative ion recording. The mass spectra of all compounds were recorded, and the characteristic ions, retention times, and detection limits were determined. The procedure was validated by evaluating the degree of the matrix suppression of ionization, extraction of analytes from human biological liquid, and the selectivity and specificity of determination.

Lunar Oxygen Production and Metals Extraction Using Ionic Liquids

NASA Technical Reports Server (NTRS)

Marone, Matthew; Paley, Mark Steven; Donovan, David N.; Karr, Laurel J.

2009-01-01

Initial results indicate that ionic liquids are promising media for the extraction of oxygen from lunar regolith. IL acid systems can solubilize regolith and produce water with high efficiency. IL electrolytes are effective for water electrolysis, and the spent IL acid media are capable of regeneration.

Determination of Polychlorinated Biphenyls in Soil and Sediment by Selective Pressurized Liquid Extraction with Immunochemical Detection

EPA Science Inventory

A selective liquid pressurized extraction (SPLE) method was developed as a streamlined sample preparation/cleanup procedure for determining Aroclors and coplanar polychlorinated biphenyls (PCBs) in soil and sediment matrices. The SPLE method was coupled with an enzyme-linked imm...

76 FR 64055 - Special Rules Governing Certain Information Obtained Under the Clean Air Act: Technical Correction

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-17

... natural gas. 211112 Natural gas liquid extraction facilities. Petrochemical Production....... 32511... facilities. 211112 Natural gas liquid extraction facilities. Suppliers of Industrial 325120 Industrial gas... reference in EPA's procedures for handling data collected under the Mandatory Greenhouse Gas Reporting Rule...

Characterization of proacrosin/acrosin system after liquid storage and cryopreservation of turkey semen (Meleagris gallopavo).

PubMed

Słowińska, M; Liszewska, E; Dietrich, G J; Ciereszko, A

2012-09-15

This study was designed to identify the effect of liquid storage at 4 °C for 48 h and cryopreservation on the proacrosin/acrosin system of turkey spermatozoa. Anti-acrosin I antibodies were produced and used to demonstrate Western blot analysis profile of the proacrosin/acrosin system of sperm and seminal plasma and possible changes in the proacrosin/acrosin system of turkey sperm stored for 2.5, 24, and 48 h or cryopreserved. At the same time acrosin-like activity was examined by the measurement of amidase activity of sperm extracts, sperm suspension, and seminal plasma of turkey semen. A computer-assisted sperm analysis system was used to monitor the sperm motility characteristics of turkey sperm stored for 48 h or cryopreserved. Different profiles of the sperm proacrosin/acrosin system were observed regarding the presence or absence of inhibitors (p-nitrophenyl-p'-guanidine benzoate [NPGB] and Kazal family inhibitor) during the extraction process. When NPGB was present three main bands were observed with the molecular weight ranging from 66 to 35 kDa. Bands corresponding to acrosin I and II were not observed. In sperm extract without NPGB, three or four bands were observed with the molecular weight ranging from 41 to 30 kDa. The bands corresponding to acrosin I and II were observed. During liquid storage a decrease in sperm motility and an increase in sperm-extracted amidase activity were observed. After 24 and 48 h of storage, extracted amidase activity was higher than at 2.5 h by 24% and 31%, respectively. However, no changes in the Western blot analysis profiles of sperm extract and seminal plasma were visible during liquid storage. After cryopreservation a decrease in sperm motility and all sperm motility parameters were observed. In contrast to liquid storage, cryopreservation did not increase extracted amidase activity. However, changes in Western blot analysis profiles were visible in sperm extract and seminal plasma after cryopreservation. After freezing-thawing, additional bands appeared in sperm extract and seminal plasma. These bands were of different molecular weight regarding the presence or absence of NPGB. These data suggest that the mechanism of damage to the proacrosin/acrosin system is different for liquid storage and cryopreservation. Liquid storage seems to increase in the susceptibility of the proacrosin/acrosin system to be activated during extraction. Kazal inhibitors of turkey seminal plasma are involved in the control of proacrosin activation. The disturbances of the proacrosin/acrosin system of turkey spermatozoa can be related to a disturbance in the induction of the acrosome reaction. Our results may be important for a better understanding of the proacrosin/acrosin system of turkey spermatozoa and disturbance to this system during liquid storage and cryopreservation. Copyright © 2012 Elsevier Inc. All rights reserved.

Phenolic composition of pomegranate peel extracts using an liquid chromatography-mass spectrometry approach with silica hydride columns.

PubMed

Young, Joshua E; Pan, Zhongli; Teh, Hui Ean; Menon, Veena; Modereger, Brent; Pesek, Joseph J; Matyska, Maria T; Dao, Lan; Takeoka, Gary

2017-04-01

The peels of different pomegranate cultivars (Molla Nepes, Parfianka, Purple Heart, Wonderful and Vkunsyi) were compared in terms of phenolic composition and total phenolics. Analyses were performed on two silica hydride based stationary phases: phenyl and undecanoic acid columns. Quantitation was accomplished by developing a liquid chromatography with mass spectrometry approach for separating different phenolic analytes, initially in the form of reference standards and then with pomegranate extracts. The high-performance liquid chromatography columns used in the separations had the ability to retain a wide polarity range of phenolic analytes, as well as offering beneficial secondary selectivity mechanisms for resolving the isobaric compounds, catechin and epicatechin. The Vkunsyi peel extract had the highest concentration of phenolics (as determined by liquid chromatography with mass spectrometry) and was the only cultivar to contain the important compound punicalagin. The liquid chromatography with mass spectrometry data were compared to the standard total phenolics content as determined by using the Folin-Ciocalteu assay. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of supported liquid membrane techniques for the monitoring of trace levels of organic pollutants in wastewaters and water purification systems

NASA Astrophysics Data System (ADS)

Msagati, Titus A. M.; Mamba, Bhekie B.

The supported liquid membrane (SLM) extraction technique has been developed and successfully used for the monitoring of trace quantities of ionisable organic contaminants, including 17β-estradiol and its metabolites, testosterones and their methyl ester derivatives, benzimidazole anthelmintic antibiotics and sulphonamides in aquatic systems. A number of parameters which control the mass transfer in the supported liquid membrane extraction process such as donor and acceptor pH, extraction time and the type of organic liquid membrane were optimised to enhance the efficiency of the liquid membrane in the removal of these compounds. The method developed gave very low detection limits (0.3 ng/l to 2.4 ng/l for 17β-estradiol and its metabolites; between 1 μg/l and 20 μg/l for sulphonamides; and between 0.1 ng/l and 10 ng/l for benzimidazole anthelmintic compounds). The SLM method showed good linearity, reproducibility and repeatability values and is therefore suitable for routine monitoring of such compounds in water and wastewater systems.

Assessment of strobilurin fungicides' content in soya-based drinks by liquid micro-extraction and liquid chromatography with tandem mass spectrometry.

PubMed

Campillo, Natalia; Iniesta, María Jesús; Viñas, Pilar; Hernández-Córdoba, Manuel

2015-01-01

Seven strobilurin fungicides were pre-concentrated from soya-based drinks using dispersive liquid-liquid micro-extraction (DLLME) with a prior protein precipitation step in acid medium. The enriched phase was analysed by liquid chromatography (LC) with dual detection, using diode array detection (DAD) and electrospray-ion trap tandem mass spectrometry (ESI-IT-MS/MS). After selecting 1-undecanol and methanol as the extractant and disperser solvents, respectively, for DLLME, the Taguchi experimental method, an orthogonal array design, was applied to select the optimal solvent volumes and salt concentration in the aqueous phase. The matrix effect was evaluated and quantification was carried out using external aqueous calibration for DAD and matrix-matched calibration method for MS/MS. Detection limits in the 4-130 and 0.8-4.5 ng g(-1) ranges were obtained for DAD and MS/MS, respectively. The DLLME-LC-DAD-MS method was applied to the analysis of 10 different samples, none of which was found to contain residues of the studied fungicides.

Preconcentration of valsartan by dispersive liquid-liquid microextraction based on solidification of floating organic drop and its determination in urine sample: Central composite design.

PubMed

Pebdani, Arezou Amiri; Shabani, Ali Mohammad Haji; Dadfarnia, Shayesteh; Talebianpoor, Mohammad Sharif; Khodadoust, Saeid

2016-05-01

In this work, a fast, easy, and efficient dispersive liquid-liquid microextraction method based on solidification of floating organic drop followed by high-performance liquid chromatography with UV detection was developed for the separation/preconcentration and determination of the drug valsartan. Experimental design was applied for the optimization of the effective variables (such as volume of extracting and dispersing solvents, ionic strength, and pH) on the extraction efficiency of valsartan from urine samples. The optimized values were 250.0 μL ethanol, 65.0 μL 1-dodecanol, 4.0% w/v NaCl, pH 3.8, 1.0 min extraction time, and 4.0 min centrifugation at 4000 rpm min(-1) . The linear response (r(2) = 0.997) was obtained in the range of 0.013-10.0 μg mL(-1) with a limit of detection of 4.0 ng mL(-1) and relative standard deviations of less than 5.0 % (n = 6). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Effect of Salts on Electrospray Ionization of Amino Acids in the Negative Mode

NASA Technical Reports Server (NTRS)

Kim, H. I.; Johnson, P. V.; Beegle, L. W.; Kanik, I.

2004-01-01

The continued search for organics on Mars will require the development of simplified procedures for handling and processing of soil or rock core samples prior to analysis by onboard instrumentation. Extraction of certain organic molecules such as amino acids from rock and soil samples using a liquid solvent (H2O) has been shown to be more efficient (by approximately an order of magnitude) than heat extraction methods. As such, liquid extraction (using H2O) of amino acid molecules from rock cores or regolith material is a prime candidate for the required processing. In this scenario, electrospray ionization (ESI) of the liquid extract would be a natural choice for ionization of the analyte prior to interrogation by one of a variety of potential analytical separation techniques (mass spectroscopy, ion mobility spectroscopy, etc.). Aside from the obvious compatibility of ESI and liquid samples, ESI offers simplicity and a soft ionization capability. In order to demonstrate that liquid extraction and ESI can work as part of an in situ instrument on Mars, we must better understand and quantify the effect salts have on the ESI process. In the current work, we have endeavored to investigate the feasibility and limitations of negative mode ESI of Martian surface samples in the context of sample salt content using ion mobility spectroscopy (IMS).

Determination of Macrolide Antibiotics Using Dispersive Liquid-Liquid Microextraction Followed by Surface-Assisted Laser Desorption/Ionization Mass Spectrometry

NASA Astrophysics Data System (ADS)

Chen, Kuan-Yu; Yang, Thomas C.; Chang, Sarah Y.

2012-06-01

A novel method for the determination of macrolide antibiotics using dispersive liquid-liquid microextraction coupled to surface-assisted laser desorption/ionization mass spectrometric detection was developed. Acetone and dichloromethane were used as the disperser solvent and extraction solvent, respectively. A mixture of extraction solvent and disperser solvent were rapidly injected into a 1.0 mL aqueous sample to form a cloudy solution. After the extraction, macrolide antibiotics were detected using surface-assisted laser desorption/ionization mass spectrometry (SALDI/MS) with colloidal silver as the matrix. Under optimum conditions, the limits of detection (LODs) at a signal-to-noise ratio of 3 were 2, 3, 3, and 2 nM for erythromycin (ERY), spiramycin (SPI), tilmicosin (TILM), and tylosin (TYL), respectively. This developed method was successfully applied to the determination of macrolide antibiotics in human urine samples.

Determination of Pyrethroids through Liquid-Liquid Extraction and GC-ECD

NASA Astrophysics Data System (ADS)

Ding, B.

2010-12-01

Storm water samples from various locations in San Diego Creek and Newport Bay watershed, southern California, were taken to study the occurrence and fate of pyrethroids. This study focused on four commonly used pyrethroids: bifenthrin, cypermethrin, permethrin, and fenpropathrin. Since the ban of DDT, usage of pyrethroids became an effective second choice. However, pyrethroids are extremely toxic to fish and aquatic organisms. They can pass through secondary wastewater treatment system, causing the final effluent to be in lethal doses to aquatic invertebrates and some insects such as mayflies. Hence, it is necessary to monitor the amount of pyrethroid concentration in storm water. As a part of this study, I attended the RISE internship program at Stanford University in this summer. In the seven weeks, I learned liquid-liquid extraction, water-bath evaporation, nitrogen evaporation, and gas chromatography-electron capture detector techniques to extract and detect the pyrethroid residues in the water sample.

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

PubMed

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.

40 CFR 98.230 - Definition of the source category.

Code of Federal Regulations, 2013 CFR

2013-07-01

... processing means the separation of natural gas liquids (NGLs) or non-methane gases from produced natural gas... following: forced extraction of natural gas liquids, sulfur and carbon dioxide removal, fractionation of... includes processing plants that fractionate gas liquids, and processing plants that do not fractionate gas...

40 CFR 98.230 - Definition of the source category.

Code of Federal Regulations, 2012 CFR

2012-07-01

... processing means the separation of natural gas liquids (NGLs) or non-methane gases from produced natural gas... following: forced extraction of natural gas liquids, sulfur and carbon dioxide removal, fractionation of... includes processing plants that fractionate gas liquids, and processing plants that do not fractionate gas...

40 CFR 98.230 - Definition of the source category.

Code of Federal Regulations, 2014 CFR

2014-07-01

... processing means the separation of natural gas liquids (NGLs) or non-methane gases from produced natural gas... following: forced extraction of natural gas liquids, sulfur and carbon dioxide removal, fractionation of... includes processing plants that fractionate gas liquids, and processing plants that do not fractionate gas...

Ambient Mass Spectrometry Imaging Using Direct Liquid Extraction Techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Laskin, Julia; Lanekoff, Ingela

2015-11-13

Mass spectrometry imaging (MSI) is a powerful analytical technique that enables label-free spatial localization and identification of molecules in complex samples.1-4 MSI applications range from forensics5 to clinical research6 and from understanding microbial communication7-8 to imaging biomolecules in tissues.1, 9-10 Recently, MSI protocols have been reviewed.11 Ambient ionization techniques enable direct analysis of complex samples under atmospheric pressure without special sample pretreatment.3, 12-16 In fact, in ambient ionization mass spectrometry, sample processing (e.g., extraction, dilution, preconcentration, or desorption) occurs during the analysis.17 This substantially speeds up analysis and eliminates any possible effects of sample preparation on the localization of moleculesmore » in the sample.3, 8, 12-14, 18-20 Venter and co-workers have classified ambient ionization techniques into three major categories based on the sample processing steps involved: 1) liquid extraction techniques, in which analyte molecules are removed from the sample and extracted into a solvent prior to ionization; 2) desorption techniques capable of generating free ions directly from substrates; and 3) desorption techniques that produce larger particles subsequently captured by an electrospray plume and ionized.17 This review focuses on localized analysis and ambient imaging of complex samples using a subset of ambient ionization methods broadly defined as “liquid extraction techniques” based on the classification introduced by Venter and co-workers.17 Specifically, we include techniques where analyte molecules are desorbed from solid or liquid samples using charged droplet bombardment, liquid extraction, physisorption, chemisorption, mechanical force, laser ablation, or laser capture microdissection. Analyte extraction is followed by soft ionization that generates ions corresponding to intact species. Some of the key advantages of liquid extraction techniques include the ease of operation, ability to analyze samples in their native environments, speed of analysis, and ability to tune the extraction solvent composition to a problem at hand. For example, solvent composition may be optimized for efficient extraction of different classes of analytes from the sample or for quantification or online derivatization through reactive analysis. In this review, we will: 1) introduce individual liquid extraction techniques capable of localized analysis and imaging, 2) describe approaches for quantitative MSI experiments free of matrix effects, 3) discuss advantages of reactive analysis for MSI experiments, and 4) highlight selected applications (published between 2012 and 2015) that focus on imaging and spatial profiling of molecules in complex biological and environmental samples.« less

Application of dispersion-solidification liquid-liquid microextraction for the determination of triazole fungicides in environmental water samples by high-performance liquid chromatography.

PubMed

Wang, Chun; Wu, Qiuhua; Wu, Chunxia; Wang, Zhi

2011-01-15

A simple, rapid and environmentally friendly method has been developed for the determination of four triazole fungicides (myclobutanil, tebuconazole, triadimenol, hexaconazole) in water samples by dispersion-solidification liquid-liquid microextraction coupled with high performance liquid chromatography-diode array detection. Several variables that affect the extraction efficiencies, including the type and volume of the extraction solvent and dispersive solvent, extraction time, effect of pH and salt addition, were investigated and optimized. Under the optimum conditions, the proposed method is sensitive and shows a good linearity within a range of 0.5-200 ng mL(-1), with the correlation coefficients (r) varying from 0.9992 to 0.9998. High enrichment factors were achieved ranging from 190 to 450. The recoveries of the target analytes from water samples at spiking levels of 1.0, 5.0 and 50.0 ng mL(-1) were between 84.8% and 110.2%. The limits of detection (LODs) for the analytes were ranged in 0.06-0.1 ng mL(-1), and the relative standard deviations (RSD) varied from 3.9% to 5.7%. The proposed method has been successfully applied for the determination of the triazole fungicides in real water samples. Copyright © 2010 Elsevier B.V. All rights reserved.

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

PubMed

Altunay, Nail; Yıldırım, Emre; Gürkan, Ramazan

2018-04-15

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

Determination of a metabolite of nifursol in foodstuffs of animal origin by liquid-liquid extraction and liquid chromatography with tandem mass spectrometry.

PubMed

Wang, Chuanxian; Qu, Li; Liu, Xia; Zhao, Chaomin; Zhao, Fengjuan; Huang, Fuzhen; Zhu, Zhenou; Han, Chao

2017-02-01

An analytical method has been developed for the detection of a metabolite of nifursol, 3,5-dinitrosalicylic acid hydrazide, in foodstuffs of animal origin (chicken liver, pork liver, lobster, shrimp, eel, sausage, and honey). The method combines liquid chromatography and tandem mass spectrometry with liquid-liquid extraction. Samples were hydrolyzed with hydrochloric acid and derivatized with 2-nitrobenzaldehyde at 37°C for 16 h. The solutions of derivatives were adjusted to pH 7.0-7.5, and the metabolite was extracted with ethyl acetate. 3,5-Dinitrosalicylic acid hydrazide determination was performed in the negative electrospray ionization method. Both isotope-labeled internal standard and matrix-matched calibration solutions were used to correct the matrix effects. Limits of quantification were 0.5 μg/kg for all samples. The average recoveries, measured at three concentration levels (0.5, 2.0, and 10 μg/kg) were in the range of 75.8-108.4% with relative standard deviations below 9.8%. The developed method exhibits a high sensitivity and selectivity for the routine determination and confirmation of the presence of a metabolite of nifursol in foodstuffs of animal origin. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of an on-line mixed-mode gel liquid chromatography×reversed phase liquid chromatography method for separation of water extract from Flos Carthami.

PubMed

Wang, Yu-Qing; Tang, Xu; Li, Jia-Fu; Wu, Yun-Long; Sun, Yu-Ying; Fang, Mei-Juan; Wu, Zhen; Wang, Xiu-Min; Qiu, Ying-Kun

2017-10-13

A novel on-line comprehensive two-dimensional liquid chromatography (2D-LC) method by coupling mixed-mode gel liquid chromatography (MMG-LC) with reversed phase liquid chromatography (RPLC) was developed. A mixture of 17 reference compounds was used to study the separation mechanism. A crude water extract of Flos Carthami was applied to evaluate the performance of the novel 2D-LC system. In the first dimension, the extract was eluted with a gradient of water/methanol over a cross-linked dextran gel Sephadex LH-20 column. Meanwhile, the advantages of size exclusion, reversed phase partition and adsorption separation mechanism were exploited before further on-line reversed phase purification on the second dimension. This novel on-line mixed-mode Sephadex LH-20×RPLC method provided higher peak resolution, sample processing ability (2.5mg) and better orthogonality (72.9%) versus RPLC×RPLC and hydrophilic interaction liquid chromatography (HILIC)×RPLC. To the best of our knowledge, this is the first report of a mixed-mode Sephadex LH-20×RPLC separation method with successful applications in on-line mode, which might be beneficial for harvesting targets from complicated medicinal plants. Copyright © 2017 Elsevier B.V. All rights reserved.

Suitability of dispersive liquid-liquid microextraction for the in situ silylation of chlorophenols in water samples before gas chromatography with mass spectrometry.

PubMed

Saraji, Mohammad; Ghambari, Hoda

2015-10-01

Trace analysis of chlorophenols in water was performed by simultaneous silylation and dispersive liquid-liquid microextraction followed by gas chromatography with mass spectrometry. Dispersive liquid-liquid microextraction was carried out using an organic solvent lighter than water (n-hexane). The effect of different silylating reagents on the method efficiency was investigated. The influence of derivatization reagent volume, presence of catalyst and derivatization/extraction time on the yield of the derivatization reaction was studied. Different parameters affecting extraction efficiency such as kind and volume of extraction and disperser solvents, pH of the sample and addition of salt were also investigated and optimized. Under the optimum conditions, the calibration graphs were linear in the range of 0.05-100 ng/mL and the limit of detection was 0.01 ng/mL. The enrichment factors were 242, 351, and 363 for 4-chlorophenol, 2,4-dichlorophenol, and 2,4,6-trichlorophenol, respectively. The values of intra- and inter-day relative standard deviations were in the range of 3.0-6.4 and 6.1-9.9%, respectively. The applicability of the method was investigated by analyzing water and wastewater samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of six pyrethroid insecticides in fruit juice samples using dispersive liquid-liquid microextraction combined with high performance liquid chromatography.

PubMed

Boonchiangma, Suthasinee; Ngeontae, Wittaya; Srijaranai, Supalax

2012-01-15

Dispersive liquid-liquid microextraction (DLLME) coupled to high performance liquid chromatography (HPLC) with UV detection was applied for the determination of six pyrethroids (tetramethrin, fenpropathrin, cypermethrin, deltamethrin, fenvalerate and permethrin) in various fruit juices including apple, red grape, orange, kiwi, passion fruit, pomegranate and guava juice. Six pyrethroids were separated within 30 min using a Waters Atlantis T3 column under an isocratic elution of acetonitrile-water (72:28). The parameters affecting extraction efficiency of the DLLME method such as type of disperser and extraction solvent, volume of disperser and extraction solvent and centrifugation time were investigated. Under the optimum conditions, 5.00 mL of sample solution, 300 μL of chloroform as extraction solvent and 1.25 mL of methanol as dispersive solvent gave high enrichment factor in the range of 62-84. Good linearity was obtained from 2 to 1,500 μg/L (r(2)>0.995). The mean recoveries of the pyrethroids evaluated by fortification of real samples were in the range of 84-94%. The limits of detection ranging from 2 to 5 μg/L are sufficient to analyze pyrethroid residues at the maximum residue limits (MRLs) established by the European Union (EU) in fruit juices. The proposed method can be applied to direct determination of pyrethroid residues in fruit juices. Copyright © 2011 Elsevier B.V. All rights reserved.

Automated dispersive liquid-liquid microextraction coupled to high performance liquid chromatography - cold vapour atomic fluorescence spectroscopy for the determination of mercury species in natural water samples.

PubMed

Liu, Yao-Min; Zhang, Feng-Ping; Jiao, Bao-Yu; Rao, Jin-Yu; Leng, Geng

2017-04-14

An automated, home-constructed, and low cost dispersive liquid-liquid microextraction (DLLME) device that directly coupled to a high performance liquid chromatography (HPLC) - cold vapour atomic fluorescence spectroscopy (CVAFS) system was designed and developed for the determination of trace concentrations of methylmercury (MeHg + ), ethylmercury (EtHg + ) and inorganic mercury (Hg 2+ ) in natural waters. With a simple, miniaturized and efficient automated DLLME system, nanogram amounts of these mercury species were extracted from natural water samples and injected into a hyphenated HPLC-CVAFS for quantification. The complete analytical procedure, including chelation, extraction, phase separation, collection and injection of the extracts, as well as HPLC-CVAFS quantification, was automated. Key parameters, such as the type and volume of the chelation, extraction and dispersive solvent, aspiration speed, sample pH, salt effect and matrix effect, were thoroughly investigated. Under the optimum conditions, linear range was 10-1200ngL -1 for EtHg + and 5-450ngL -1 for MeHg + and Hg 2+ . Limits of detection were 3.0ngL -1 for EtHg + and 1.5ngL -1 for MeHg + and Hg 2+ . Reproducibility and recoveries were assessed by spiking three natural water samples with different Hg concentrations, giving recoveries from 88.4-96.1%, and relative standard deviations <5.1%. Copyright © 2017 Elsevier B.V. All rights reserved.

Dispersive liquid-liquid microextraction followed by high-performance liquid chromatography-ultraviolet detection to determination of opium alkaloids in human plasma.

PubMed

Ahmadi-Jouibari, Toraj; Fattahi, Nazir; Shamsipur, Mojtaba; Pirsaheb, Meghdad

2013-11-01

A novel, simple, rapid and sensitive dispersive liquid-liquid microextraction method based on the solidification of floating organic drop (DLLME-SFO) combined with high-performance liquid chromatography-ultraviolet detection (HPLC-UV) was used to determine opium alkaloids in human plasma. During the extraction procedure, plasma protein was precipitated by using a mixture of zinc sulfate solution and acetonitrile. Some effective parameters on extraction were studied and optimized. Under the optimum conditions (extraction solvent: 30.0 μl 1-undecanol; disperser solvent: 470 μl acetone; pH: 9; salt addition: 1%(w/v) NaCl and extraction time: 0.5 min), calibration curves are linear in the range of 1.5-1000 μgl(-1) and limit of detections (LODs) are in the range of 0.5-5 μgl(-1). The relative standard deviations (RSDs) for 100 μgl(-1) of morphine and codeine, 10.0 μgl(-1) of papaverine and 20.0 μgl(-1) of noscapine in diluted human plasma are in the range of 4.3-7.4% (n=5). Finally, the method was successfully applied in the determination of opium alkaloids in the actual human plasma samples. The relative recoveries of plasma samples spiked with alkaloids are 88-110.5%. The obtained results show that DLLME-SFO combined with HPLC-UV is a fast and simple method for the determination of opium alkaloids in human plasma. Copyright © 2013 Elsevier B.V. All rights reserved.

Determination of atranol and chloroatranol in perfumes using simultaneous derivatization and dispersive liquid-liquid microextraction followed by gas chromatography-mass spectrometry.

PubMed

López-Nogueroles, Marina; Chisvert, Alberto; Salvador, Amparo

2014-05-15

A new analytical method based on simultaneous derivatization and dispersive liquid-liquid microextraction (DLLME) followed by gas chromatography-mass spectrometry (GC-MS), for the determination of the allergenic compounds atranol and chloroatranol in perfumes, is presented. Derivatization of the target analytes by means of acetylation with anhydride acetic in carbonate buffer was carried out. Thereby volatility and detectability were increased for improved GC-MS sensitivity. In addition, extractability by DLLME was also enhanced due to a less polar character of the solutes. A liquid-liquid extraction was performed before DLLME to clean up the sample and to obtain an aqueous sample solution, free of the low polar matrix from the essential oils, as donor phase. Different parameters, such as the nature and volume of both the extraction and disperser solvents, the ionic strength of the aqueous donor phase or the effect of the derivatization reagent volume, were optimized. Under the selected conditions (injection of a mixture of 750μL of acetone as disperser solvent, 100μL of chloroform as extraction solvent and 100μL of anhydride acetic as derivatization reagent) the figures of merit of the proposed method were evaluated. Limits of detection in the low ngmL(-1) range were obtained. Matrix effect was observed in real perfume samples and thus, standard addition calibration is recommended. Copyright © 2014 Elsevier B.V. All rights reserved.

A novel task specific magnetic polymeric ionic liquid for selective preconcentration of potassium in oil samples using centrifuge-less dispersive liquid-liquid microextraction technique and its determination by flame atomic emission spectroscopy.

PubMed

Beiraghi, Asadollah; Shokri, Masood

2018-02-01

In the present study a new centrifuge-less dispersive liquid-liquid microextraction technique based on application of a new task specific magnetic polymeric ionic liquid (TSMPIL) as a chelating and extraction solvent for selective preconcentration of trace amounts of potassium from oil samples is developed, for the first time. After extraction, the fine droplets of TSMPIL were transferred into an eppendorf tube and diluted to 500µL using distilled water. Then, the enriched analyte was determined by flame atomic emission spectroscopy (FAES). Several important factors affecting both the complexation and extraction efficiency including extraction time, rate of vortex agitator, amount of carbonyl iron powder, pH of sample solution, volume of ionic liquid as well as effects of interfering species were investigated and optimized. Under the optimal conditions, the limits of detection (LOD) and quantification (LOQ) were 0.5 and 1.6µgL -1 respectively with the preconcentration factor of 128. The precision (RSD %) for seven replicate determinations at 10µgL -1 of potassium was better than 3.9%. The relative recoveries for the spiked samples were in the acceptable range of 95-104%. The results demonstrated that no remarkable interferences are created by other various ions in the determination of potassium, so that the tolerance limits (W Ion /W K ) of major cations and anions were in the range of 2500-10,000. The purposed method was successfully applied for the analysis of potassium in some oil samples. Copyright © 2017 Elsevier B.V. All rights reserved.

In situ metathesis reaction combined with liquid-phase microextraction based on the solidification of sedimentary ionic liquids for the determination of pyrethroid insecticides in water samples.

PubMed

Hu, Lu; Zhang, Panjie; Shan, Wanyu; Wang, Xuan; Li, Songqing; Zhou, Wenfeng; Gao, Haixiang

2015-11-01

A novel dispersion liquid-liquid microextraction method based on the solidification of sedimentary ionic liquids (SSIL-DLLME), in which an in situ metathesis reaction forms an ionic liquid (IL) extraction phase, was developed to determine four pyrethroid insecticides (i.e., permethrin, cyhalothrin, fenpropathrin, and transfluthrin) in water followed by separation using high-performance liquid chromatography. In the developed method, in situ DLLME was used to enhance the extraction efficiency and yield. After centrifugation, the extraction solvent, tributyldodecylphosphonium hexafluorophosphate ([P44412][PF6]), was easily collected by solidification in the bottom of the tube. The effects of various experimental parameters, the quantity of tributyldodecylphosphonium bromide ([P44412]Br), the molar ratio of [P44412]Br to potassium hexafluorophosphate (KPF6), the ionic strength, the temperature of the sample solution, and the centrifugation time, were optimized using a Plackett-Burman design to identify the significant factors that affected the extraction efficiency. These significant factors were then optimized using a central composite design. Under the optimized conditions, the recoveries of the four pyrethroid insecticides at four spiked levels ranged from 87.1% to 101.7%, with relative standard deviations (RSDs) ranging from 0.1% to 5.5%. At concentration levels between 1 and 500 µg/L, good linearity was obtained, with coefficients of determination greater than 0.9995. The limits of detection (LODs) for the four pyrethroid insecticides were in the range of 0.71-1.54 µg/L. The developed method was then successfully used for the determination of pyrethroid insecticides in environmental samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Binary Solvents Dispersive Liquid—Liquid Microextraction (BS-DLLME) Method for Determination of Tramadol in Urine Using High-Performance Liquid Chromatography

PubMed Central

2014-01-01

Background Tramadol is an opioid, synthetic analog of codeine and has been used for the treatment of acute or chronic pain may be abused. In this work, a developed Dispersive liquid liquid microextraction (DLLME) as binary solvents-based dispersive liquid-liquid microextraction (BS-DLLME) combined with high performance liquid chromatography (HPLC) with fluorescence detection (FD) was employed for determination of tramadol in the urine samples. This procedure involves the use of an appropriate mixture of binary extraction solvents (70 μL CHCl3 and 30 μL ethyl acetate) and disperser solvent (600 μL acetone) for the formation of cloudy solution in 5 ml urine sample comprising tramadol and NaCl (7.5%, w/v). After centrifuging, the small droplets of extraction solvents were precipitated. In the final step, the HPLC with fluorescence detection was used for determination of tramadol in the precipitated phase. Results Various factors on the efficiency of the proposed procedure were investigated and optimized. The detection limit (S/N = 3) and quantification limit (S/N = 10) were found 0.2 and 0.9 μg/L, respectively. The relative standard deviations (RSD) for the extraction of 30 μg L of tramadol was found 4.1% (n = 6). The relative recoveries of tramadol from urine samples at spiking levels of 10, 30 and 60 μg/L were in the range of 95.6 – 99.6%. Conclusions Compared with other methods, this method provides good figures of merit such as good repeatability, high extraction efficiency, short analysis time, simple procedure and can be used as microextraction technique for routine analysis in clinical laboratories. PMID:24495475

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

ERIC Educational Resources Information Center

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).…

Method and apparatus using an active ionic liquid for algae biofuel harvest and extraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salvo, Roberto Di; Reich, Alton; Dykes, Jr., H. Waite H.

The invention relates to use of an active ionic liquid to dissolve algae cell walls. The ionic liquid is used to, in an energy efficient manner, dissolve and/or lyse an algae cell walls, which releases algae constituents used in the creation of energy, fuel, and/or cosmetic components. The ionic liquids include ionic salts having multiple charge centers, low, very low, and ultra low melting point ionic liquids, and combinations of ionic liquids. An algae treatment system is described, which processes wet algae in a lysing reactor, separates out algae constituent products, and optionally recovers the ionic liquid in an energymore » efficient manner.« less

Air-assisted liquid-liquid microextraction using floating organic droplet solidification for simultaneous extraction and spectrophotometric determination of some drugs in biological samples through chemometrics methods

NASA Astrophysics Data System (ADS)

Farahmand, Farnaz; Ghasemzadeh, Bahar; Naseri, Abdolhossein

2018-01-01

An air assisted liquid-liquid microextraction by applying the solidification of a floating organic droplet method (AALLME-SFOD) coupled with a multivariate calibration method, namely partial least squares (PLS), was introduced for the fast and easy determination of Atenolol (ATE), Propanolol (PRO) and Carvedilol (CAR) in biological samples via a spectrophotometric approach. The analytes would be extracted from neutral aqueous solution into 1-dodecanol as an organic solvent, using AALLME. In this approach a low-density solvent with a melting point close to room temperature was applied as the extraction solvent. The emulsion was immediately formed by repeatedly pulling in and pushing out the aqueous sample solution and extraction solvent mixture via a 10-mL glass syringe for ten times. After centrifugation, the extractant droplet could be simply collected from the aqueous samples by solidifying the emulsion at a lower than the melting point temperature. In the next step, analytes were back extracted simultaneously into the acidic aqueous solution. Derringer and Suich multi-response optimization were utilized for simultaneous optimizing the parameters of three analytes. This method incorporates the benefits of AALLME and dispersive liquid-liquid microextraction considering the solidification of floating organic droplets (DLLME-SFOD). Calibration graphs under optimized conditions were linear in the range of 0.30-6.00, 0.32-2.00 and 0.30-1.40 μg mL- 1 for ATE, CAR and PRO, respectively. Other analytical parameters were obtained as follows: enrichment factors (EFs) were found to be 11.24, 16.55 and 14.90, and limits of detection (LODs) were determined to be 0.09, 0.10 and 0.08 μg mL- 1 for ATE, CAR and PRO, respectively. The proposed method will require neither a highly toxic chlorinated solvent for extraction nor an organic dispersive solvent in the application process; hence, it is more environmentally friendly.

[Rapid identification of micro-constituents in monoammonium glycyrrhizinate raw materials by high-pressure solid phase extraction-high performance liquid chromatography-mass spectrometry].

PubMed

Yang, Xue-Dong; Tang, Xu-Yan; Sang, Lin

2012-11-01

To establish a method for rapid identification of micro-constituents in monoammonium glycyrrhizinate by high-pressure solid phase extraction-high performance liquid chromatography-mass spectrometry. HPLC preparative chromatograph was adopted for determining the optimal method for high-pressure solid phase extraction under optimal conditions. 5C18-MS-II column (20.0 mm x 20.0 mm) was used as the extraction column, with 35% acetonitrile-acetic acid solution (pH 2. 20) as eluent at the speed of 16 mL x min(-1). The sample size was 0.5 mL, and the extraction cycle was 4.5 min. Then, extract liquid was analyzed by high performance liquid chromatography-mass spectrometry (HPLC-MS) after being concentrated by 100 times. Under the optimal condition of high-pressure solid phase extraction-high performance liquid chromatography-mass spectrometry, 10 components were rapidly identified from monoammonium glycyrrhizinate raw materials. Among them, the chemical structures of six micro-constituents were identified as 3-O-[beta-D-glucuronopyranosyl-beta-D-glucuronopyranosyl]-30-0-beta-D-apiopyranosylglycyrrhetic/3-O- [P-D-glucuronopyranosyl-beta-D-glucuronopyranosyl]-30-O-beta-D-arabinopyranosylglycyrrhetic, glycyrrhizic saponin F3, 22-hydroxyglycyrrhizin/18alpha-glycyrrhizic saponin G2, 3-O-[beta-D-rhamnopyranosyl]-24-hydroxyglycyrrhizin, glycyrrhizic saponin J2, and glycyrrhizic saponin B2 by MS(n) spectra analysis and reference to literatures. Four main chemical components were identified as glycyrrhizic saponin G2, 18beta-glycyrrhizic acid, uralglycyrrhizic saponin B and 18alpha-glycyrrhizic acid by liquid chromatography, MS(n) and ultraviolet spectra information and comparison with reference substances. The method can be used to identify chemical constituents in monoammonium glycyrrhizinate quickly and effectively, without any reference substance, which provides basis for quality control and safe application of monoammonium glycyrrhizinate-related products.

Air-assisted liquid-liquid microextraction using floating organic droplet solidification for simultaneous extraction and spectrophotometric determination of some drugs in biological samples through chemometrics methods.

PubMed

Farahmand, Farnaz; Ghasemzadeh, Bahar; Naseri, Abdolhossein

2018-01-05

An air assisted liquid-liquid microextraction by applying the solidification of a floating organic droplet method (AALLME-SFOD) coupled with a multivariate calibration method, namely partial least squares (PLS), was introduced for the fast and easy determination of Atenolol (ATE), Propanolol (PRO) and Carvedilol (CAR) in biological samples via a spectrophotometric approach. The analytes would be extracted from neutral aqueous solution into 1-dodecanol as an organic solvent, using AALLME. In this approach a low-density solvent with a melting point close to room temperature was applied as the extraction solvent. The emulsion was immediately formed by repeatedly pulling in and pushing out the aqueous sample solution and extraction solvent mixture via a 10-mL glass syringe for ten times. After centrifugation, the extractant droplet could be simply collected from the aqueous samples by solidifying the emulsion at a lower than the melting point temperature. In the next step, analytes were back extracted simultaneously into the acidic aqueous solution. Derringer and Suich multi-response optimization were utilized for simultaneous optimizing the parameters of three analytes. This method incorporates the benefits of AALLME and dispersive liquid-liquid microextraction considering the solidification of floating organic droplets (DLLME-SFOD). Calibration graphs under optimized conditions were linear in the range of 0.30-6.00, 0.32-2.00 and 0.30-1.40μg mL -1 for ATE, CAR and PRO, respectively. Other analytical parameters were obtained as follows: enrichment factors (EFs) were found to be 11.24, 16.55 and 14.90, and limits of detection (LODs) were determined to be 0.09, 0.10 and 0.08μg mL -1 for ATE, CAR and PRO, respectively. The proposed method will require neither a highly toxic chlorinated solvent for extraction nor an organic dispersive solvent in the application process; hence, it is more environmentally friendly. Copyright © 2017 Elsevier B.V. All rights reserved.

A systematic review and meta-analysis of pneumonia associated with thin liquid vs. thickened liquid intake in patients who aspirate.

PubMed

Kaneoka, Asako; Pisegna, Jessica M; Saito, Hiroki; Lo, Melody; Felling, Katey; Haga, Nobuhiko; LaValley, Michael P; Langmore, Susan E

2017-08-01

To investigate whether drinking thin liquids with safety strategies increases the risk for pneumonia as compared with thickened liquids in patients who have demonstrated aspiration of thin liquids. Seven electronic databases, one clinical register, and three conference archives were searched. No language or publication date restrictions were imposed. Reference lists were scanned and authors and experts in the field were contacted. A blind review was performed by two reviewers for published or unpublished randomized controlled trials and prospective non-randomized trials comparing the incidence of pneumonia with intake of thin liquids plus safety strategies vs. thickened liquids in adult patients who aspirated on thin liquids. The data were extracted from included studies. Odds ratios (OR) for pneumonia were calculated from the extracted data. Risk of bias was also assessed with the included published trials. Seven studies out of 2465 studies including 650 patients met the inclusion criteria. All of the seven studies excluded patients with more than one known risk factor for pneumonia. Six studies compared thin water protocols to thickened liquids for pneumonia prevention. A meta-analysis was done on the six studies, showing no significant difference for pneumonia risk (OR = 0.82; 95% CI = 0.05-13.42; p = 0.89). There was no significant difference in the risk of pneumonia in aspirating patients who took thin liquids with safety strategies compared with those who took thickened liquids only. This result, however, is generalizable only for patients with low risk of pneumonia.

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

PubMed Central

Zhao, Chunjian; Lu, Zhicheng; He, Xin; Li, Zhao; Shi, Kunming; Yang, Lei; Fu, Yujie; Zu, Yuangang

2014-01-01

An ionic liquids based simultaneous ultrasonic and microwave assisted extraction (ILs-UMAE) method has been proposed for the extraction of rutin (RU), quercetin (QU), from velvetleaf leaves. The influential parameters of the ILs-UMAE were optimized by the single factor and the central composite design (CCD) experiments. A 2.00 M 1-butyl-3-methylimidazolium bromide ([C4mim]Br) was used as the experimental ionic liquid, extraction temperature 60°C, extraction time 12 min, liquid-solid ratio 32 mL/g, microwave power of 534 W, and a fixed ultrasonic power of 50 W. Compared to conventional heating reflux extraction (HRE), the RU and QU extraction yields obtained by ILs-UMAE were, respectively, 5.49 mg/g and 0.27 mg/g, which increased, respectively, 2.01-fold and 2.34-fold with the recoveries that were in the range of 97.62–102.36% for RU and 97.33–102.21% for QU with RSDs lower than 3.2% under the optimized UMAE conditions. In addition, the shorter extraction time was used in ILs-UMAE, compared with HRE. Therefore, ILs-UMAE was a rapid and an efficient method for the extraction of RU and QU from the leaves of velvetleaf. PMID:25243207

EXTRACTION AND QUANTITATIVE ANALYSIS OF ELEMENTAL SULFUR FROM SULFIDE MINERAL SURFACES BY HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY. (R826189)

EPA Science Inventory

A simple method for the quantitative determination of elemental sulfur on oxidized sulfide minerals is described. Extraction of elemental sulfur in perchloroethylene and subsequent analysis with high-performance liquid chromatography were used to ascertain the total elemental ...

COMPARISON OF TWO DIFFERENT SOLID PHASE EXTRACTION/LARGE VOLUME INJECTION PROCEDURES FOR METHOD 8270

EPA Science Inventory

Two solid phase (SPE) and one traditional continuous liquid-liquid extraction method are compared for analysis of Method 8270 SVOCs. Productivity parameters include data quality, sample volume, analysis time and solvent waste.

One SPE system, unique in the U.S., uses aut...

DETERMINATION OF PERCHLORATE AT TRACE LEVELS IN DRINKING WATER BY ION-PAIR EXTRACTION WITH ELECTROSPRAY IONIZATION MASS SPECTROMETRY.

EPA Science Inventory

Perchlorate has been added to the U.S. Environmental Protection Agency,s Drinking Water Contaminant Candidate List (CCL). The present work describes the analysis of perchlorate in water by liquid-liquid extraction followed by flow injection electrospray mass spectrometry (ESI/MS...

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.

PubMed

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.

Determination of endocrine-disrupting compounds in water samples by magnetic nanoparticle-assisted dispersive liquid-liquid microextraction combined with gas chromatography-tandem mass spectrometry.

PubMed

Pérez, Rosa Ana; Albero, Beatriz; Tadeo, José Luis; Sánchez-Brunete, Consuelo

2016-11-01

A rapid extraction procedure is presented for the determination of five endocrine-disrupting compounds, estrone, ethinylestradiol, bisphenol A, triclosan, and 2-ethylhexylsalicylate, in water samples. The analysis involves a two-step extraction procedure that combines dispersive liquid-liquid microextraction (DLLME) with dispersive micro-solid phase extraction (D-μ-SPE), using magnetic nanoparticles, followed by in situ derivatization in the injection port of a gas chromatograph coupled to triple quadrupole mass spectrometry. The use of uncoated or oleate-coated Fe 3 O 4 nanoparticles as sorbent in the extraction process was evaluated and compared. The main parameters involved in the extraction process were optimized applying experimental designs. Uncoated Fe 3 O 4 nanoparticles were selected in order to simplify and make more cost-effective the procedure. DLLME was carried out at pH 3, during 2 min, followed by the addition of the nanoparticles for D-μ-SPE employing 1 min in the extraction. Analysis of spiked water samples of different sources gave satisfactory recovery results for all the compounds with detection limits ranging from 7 to 180 ng l -1 . Finally, the procedure was applied in tap, well, and river water. Graphical abstract Diagram of the extraction method using magnetic nanoparticles (MNPs).

Solar-Driven Liquid-Metal MHD Generator

NASA Technical Reports Server (NTRS)

Hohl, F.; Lee, J. H.

1982-01-01

Liquid-metal magnetohydrodynamic (MHD) power generator with solar oven as its heat source has potential to produce electric power in space and on Earth at high efficiency. Generator focuses radiation from Sun to heat driving gas that pushes liquid metal past magnetic coil. Power is extracted directly from electric currents set up in conducting liquid. Using solar energy as fuel can save considerable costs and payload weight, compared to previous systems.

Measuring Interfacial Tension Between Immiscible Liquids

NASA Technical Reports Server (NTRS)

Rashidnia, Nasser; Balasubramaniam, R.; Delsignore, David M.

1995-01-01

Glass capillary tube technique measures interfacial tension between two immiscible liquids. Yields useful data over fairly wide range of interfacial tensions, both for pairs of liquids having equal densities and pairs of liquids having unequal densities. Data on interfacial tensions important in diverse industrial chemical applications, including enhanced extraction of oil; printing; processing foods; and manufacture of paper, emulsions, foams, aerosols, detergents, gel encapsulants, coating materials, fertilizers, pesticides, and cosmetics.

High-performance liquid chromatographic determination of ambroxol in human plasma.

PubMed

Nobilis, M; Pastera, J; Svoboda, D; Kvêtina, J; Macek, K

1992-10-23

Ambroxol has been determined in biological fluids using a rapid and sensitive high-performance liquid chromatographic method. The samples prepared from plasma by liquid-liquid extraction were analysed on reversed-phase silica gel by competing-ion chromatography with ultraviolet detection. The method was applied to the determination of ambroxol levels in twelve healthy volunteers after oral administration of 90 mg of ambroxol in tablets of Mucosolvan and Ambrosan.

Selective separation of trivalent f-ions using 1,10-phenanthroline-2,9-dicarboxamide ligands in ionic liquids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dehaudt, Jeremy; Williams, Neil J.; Shkrob, Ilya A.

1,10-Phenanthroline-2,9-dicarboxamide complexants decorated with alkyl chains and imidazolium cations have been studied for extraction of trivalent f-ions into imidazolium ionic liquids. The dicationic complexants are shown to extract Am over Eu with separation factors > 50 and high extraction efficiencies. Lastly, the different size selectivities for lanthanide ions were observed for these two types of the complexants, highlighting the importance of the positive charge in controlling both extraction efficiencies and extraction selectivities.

Selective separation of trivalent f-ions using 1,10-phenanthroline-2,9-dicarboxamide ligands in ionic liquids

DOE PAGES

Dehaudt, Jeremy; Williams, Neil J.; Shkrob, Ilya A.; ...

2016-06-13

1,10-Phenanthroline-2,9-dicarboxamide complexants decorated with alkyl chains and imidazolium cations have been studied for extraction of trivalent f-ions into imidazolium ionic liquids. The dicationic complexants are shown to extract Am over Eu with separation factors > 50 and high extraction efficiencies. Lastly, the different size selectivities for lanthanide ions were observed for these two types of the complexants, highlighting the importance of the positive charge in controlling both extraction efficiencies and extraction selectivities.

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

PubMed

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

2017-08-04

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

Green aspects, developments and perspectives of liquid phase microextraction techniques.

PubMed

Spietelun, Agata; Marcinkowski, Łukasz; de la Guardia, Miguel; Namieśnik, Jacek

2014-02-01

Determination of analytes at trace levels in complex samples (e.g. biological or contaminated water or soils) are often required for the environmental assessment and monitoring as well as for scientific research in the field of environmental pollution. A limited number of analytical techniques are sensitive enough for the direct determination of trace components in samples and, because of that, a preliminary step of the analyte isolation/enrichment prior to analysis is required in many cases. In this work the newest trends and innovations in liquid phase microextraction, like: single-drop microextraction (SDME), hollow fiber liquid-phase microextraction (HF-LPME), and dispersive liquid-liquid microextraction (DLLME) have been discussed, including their critical evaluation and possible application in analytical practice. The described modifications of extraction techniques deal with system miniaturization and/or automation, the use of ultrasound and physical agitation, and electrochemical methods. Particular attention was given to pro-ecological aspects therefore the possible use of novel, non-toxic extracting agents, inter alia, ionic liquids, coacervates, surfactant solutions and reverse micelles in the liquid phase microextraction techniques has been evaluated in depth. Also, new methodological solutions and the related instruments and devices for the efficient liquid phase micoextraction of analytes, which have found application at the stage of procedure prior to chromatographic determination, are presented. © 2013 Published by Elsevier B.V.

Monitoring leachables from single-use bioreactor bags for mammalian cell culture by dispersive liquid-liquid microextraction followed by ultra high performance liquid chromatography quadrupole time of flight mass spectrometry.

PubMed

Dorival-García, N; Bones, J

2017-08-25

A method for the identification of leachables in chemically defined media for CHO cell culture using dispersive liquid-liquid microextraction (DLLME) and UHPLC-MS is described. A Box-Behnken design of experiments (DoE) approach was applied to obtain the optimum extraction conditions of the target analytes. Performance of DLLME as extraction technique was studied by comparison of two commercial chemically defined media for CHO cell culture. General extraction conditions for any group of leachables, regardless of their specific chemical functionalities can be applied and similar optimum conditions were obtained with the two media. Extraction efficiency and matrix effects were determined. The method was validated using matrix-matched standard calibration followed by recovery assays with spiked samples. Finally, cell culture media was incubated in 7 single use bioreactors (SUBs) from different vendors and analysed. TBPP was not detected in any of the samples, whereas DtBP and TBPP-ox were found in all samples, with bDtBPP detected in six SUBs. This method can be used for early identification of non-satisfactory SUB films for cultivation of CHO cell lines for biopharmaceutical production. Copyright © 2017 Elsevier B.V. All rights reserved.

Centrifugal contactor modified for end stage operation in a multistage system

DOEpatents

Jubin, Robert T.

1990-01-01

A cascade formed of a plurality of centrifugal contactors useful for countercurrent solvent extraction processes such as utilizable for the reprocessing of nuclear reactor fuels is modified to permit operation in the event one or both end stages of the cascade become inoperative. Weir assemblies are connected to each of the two end stages by suitable conduits for separating liquids discharged from an inoperative end stage based upon the weight of the liquid phases uses in the solvent extraction process. The weir assembly at one end stage is constructed to separate and discharge the heaviest liquid phase while the weir assembly at the other end stage is constructed to separate and discharge the lightest liquid phase. These weir assemblies function to keep the liquid discharge from an inoperative end stages on the same weight phase a would occur from an operating end stage.

Hollow fibre liquid phase micro-extraction by facilitated anionic exchange for the determination of flavonoids in faba beans (Vicia faba L.).

PubMed

Chaieb, Nadia; López-Mesas, Montserrat; Luis González, Johannes; Mars, Messaoud; Valiente, Manuel

2015-01-01

Flavonoids are polyphenolic compounds found ubiquitously in foods of plant origin. They are commonly extracted from plant materials with ethanol, methanol, water, their combination or even with acidified extracting solutions. The disadvantages of these methods are the use of high quantity of organic solvent, the possible loss of analytes in the different steps and the laborious process of the techniques. In addition, the complexity of the phenolic mixtures present in plant materials requires a preliminary clean-up and fractionation of the crude extracts. To develop a hollow fibre liquid phase micro-extraction (HF-LPME) method for a one step clean-up and pre-concentration of flavonoids. Two flavonoids (catechin and rutin) has been extracted by HF-LPME and analysed by HPLC. The related driving force for the liquid membrane has been studied by means of facilitated and non-facilitated transport. Different ionic and non-ionic water insoluble compounds [trioctylamine (TOA), tributyl phosphate (TBP), trioctylphosphine oxide (TOPO) and methyltrioctylammonium chloride (aliquat 336)] were used as carriers. The liquid membrane was constituted by a solution of n-decanol in the presence or absence of carriers. Maximum enrichment factors were obtained with n-decanol/aliquat 336 (20%) as organic liquid membrane, sodium hydroxide (NaOH) (0.1 M) as donor solution, sodium chloride (NaCl) (2 M) as acceptor solution and 3 h as extraction time. Under these conditions, good results for validation parameters were obtained [for linearity, limit of detection (LOD), limit of quantitation (LOQ) and repeatability]. The developed method is simple, effective and has been successfully applied to determine catechin and rutin in ethanolic extracts of faba beans. Copyright © 2015 John Wiley & Sons, Ltd.

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

PubMed

Sadeghi, Susan; Ashoori, Vahid

2017-10-01

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

Selective Extraction of Uranium from Liquid or Supercritical Carbon Dioxide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Farawila, Anne F.; O'Hara, Matthew J.; Wai, Chien M.

2012-07-31

Current liquid-liquid extraction processes used in recycling irradiated nuclear fuel rely on (1) strong nitric acid to dissolve uranium oxide fuel, and (2) the use of aliphatic hydrocarbons as a diluent in formulating the solvent used to extract uranium. The nitric acid dissolution process is not selective. It dissolves virtually the entire fuel meat which complicates the uranium extraction process. In addition, a solvent washing process is used to remove TBP degradation products, which adds complexity to the recycling plant and increases the overall plant footprint and cost. A liquid or supercritical carbon dioxide (l/sc -CO2) system was designed tomore » mitigate these problems. Indeed, TBP nitric acid complexes are highly soluble in l/sc -CO2 and are capable of extracting uranium directly from UO2, UO3 and U3O8 powders. This eliminates the need for total acid dissolution of the irradiated fuel. Furthermore, since CO2 is easily recycled by evaporation at room temperature and pressure, it eliminates the complex solvent washing process. In this report, we demonstrate: (1) A reprocessing scheme starting with the selective extraction of uranium from solid uranium oxides into a TBP-HNO3 loaded Sc-CO2 phase, (2) Back extraction of uranium into an aqueous phase, and (3) Conversion of recovered purified uranium into uranium oxide. The purified uranium product from step 3 can be disposed of as low level waste, or mixed with enriched uranium for use in a reactor for another fuel cycle. After an introduction on the concept and properties of supercritical fluids, we first report the characterization of the different oxides used for this project. Our extraction system and our online monitoring capability using UV-Vis absorbance spectroscopy directly in sc-CO2 is then presented. Next, the uranium extraction efficiencies and kinetics is demonstrated for different oxides and under different physical and chemical conditions: l/sc -CO2 pressure and temperature, TBP/HNO3 complex used, reductant or complexant used for selectivity, and ionic liquids used as supportive media. To complete the extraction and recovery cycle, we then demonstrate uranium back extraction from the TBP loaded sc-CO2 phase into an aqueous phase and the characterization of the uranium complex formed at the end of this process. Another aspect of this project was to limit proliferation risks by either co-extracting uranium and plutonium, or by leaving plutonium behind by selectively extracting uranium. We report that the former is easily achieved, since plutonium is in the tetravalent or hexavalent oxidation state in the oxidizing environment created by the TBP-nitric acid complex, and is therefore co-extracted. The latter is more challenging, as a reductant or complexant to plutonium has to be used to selectively extract uranium. After undertaking experiments on different reducing or complexing systems (e.g., AcetoHydroxamic Acid (AHA), Fe(II), ascorbic acid), oxalic acid was chosen as it can complex tetravalent actinides (Pu, Np, Th) in the aqueous phase while allowing the extraction of hexavalent uranium in the sc-CO2 phase. Finally, we show results using an alternative media to commonly used aqueous phases: ionic liquids. We show the dissolution of uranium in ionic liquids and its extraction using sc-CO2 with and without the presence of AHA. The possible separation of trivalent actinides from uranium is also demonstrated in ionic liquids using neodymium as a surrogate and diglycolamides as the extractant.« less

Salting-out assisted liquid-liquid extraction for the determination of biogenic amines in fruit juices and alcoholic beverages after derivatization with 1-naphthylisothiocyanate and high performance liquid chromatography.

PubMed

Jain, Archana; Gupta, Manju; Verma, Krishna K

2015-11-27

A new method for determining biogenic amines in fruit juices and alcoholic beverages is described involving reaction of biogenic amines with 1-naphthylisothiocyanate followed by extraction of 1-naphthylthiourea derivatives with water-miscible organic solvent acetonitrile when solvents phase separation occurred using ammonium sulphate, a process called salting-out assisted liquid-liquid extraction. The extract was analyzed by high-performance liquid chromatography with UV detection at 254nm. The new reagent avoided many of the inconveniences as observed with existing derivatizing agents, such as dansyl chloride and benzoyl chloride, in regard to their inselectivity, instability, adverse effect of excess reagent, and necessity to remove excess reagent. The procedure has been optimized with respect to reaction time and temperature, water-miscible extraction solvent, and salt for solvents phase separation. Use of reagent as dispersed phase in aqueous medium produced derivatives in high yield. A linear calibration was obtained between the amount of biogenic amines in range 1-1000μgL(-1) and peak areas of corresponding thioureas formed; the correlation coefficient was 0.9965, and the limit of detection and limit of quantification found were 1.1μgL(-1) and 3.2μgL(-1), respectively. The pre-concentration method gave an average enrichment factor of 94. The application of the method has been demonstrated in the determination of biogenic amines in commercial samples of fruit juices and alcoholic beverages. In spiking experiments to real samples, the average recovery found by the present method was 94.5% that agreed well with 95.8% obtained by established comparison methods. Copyright © 2015 Elsevier B.V. All rights reserved.

Benzene and cyclohexane separation using 1-butyl-3-methylimidazolium thiocyanate

NASA Astrophysics Data System (ADS)

Gonfa, Girma; Ismail, Marhaina; Bustam, Mohamad Azmi

2017-09-01

Cyclohexane is mainly produced by catalytic hydrogenation of benzene. Removal of unreacted benzene from the product stream is very important in this process. However, due to their close boiling points and azeotrope formation, it is very difficult to separate cyclohexane and benzene by conventional distillation. Currently, special separation processes such as processes extractive distillation is commercially used for this separation. However, this extractive distillation suffers from process complexity and higher energy consumption due to their low extractive selectivity of molecular entrainers used. The aim of the present work is to investigate the applicability of ionic liquids as entrainer in extractive distillation of benzene and cyclohexane mixture. In this study, we investigated 1-butyl-3-methylimidazolium thiocyanate ([BMIM][SCN]) ionic liquid for separation of benzene and cyclohexane by measuring the Vapor Liquid Equilibrium data of the two components in the presence of the ionic liquid. As green and potential environmentally friendly solvents, ionic liquids have attracted increasing attention as alternative conventional entrainers in extractive distillation. Isothermal Vapor Liquid Equilibrium for the benzene + cyclohexane + [BMIM][SCN] ternary system was obtained at 353.15 K using a Head Space Gas Chromatography. The addition of [BMIM][SCN] breaks the benzene-cyclohexane azeotrope and increased the relative volatility cyclohexane to benzene in the mixture. The effect of [BMIM][SCN] on the relative volatility cyclohexane to benzene was studied at various benzene and cyclohexane compositions and solvent to feed ratios. The performance of [BMIM][SCN] was compared with typical conventional solvents, dimethylformamide (DMF) and dimethylsulfoxide (DMSO). The results show that the relative volatility of cyclohexane to benzene in the presence of [BMIM][SCN] is higher compared that of DMSO and DMF.

Ionic liquids gels: Soft materials for environmental remediation.

PubMed

Marullo, Salvatore; Rizzo, Carla; Dintcheva, Nadka T; Giannici, Francesco; D'Anna, Francesca

2018-05-01

Nanostructured sorbents and, in particular, supramolecular gels are emerging as efficient materials for the removal of toxic contaminants from water, like industrial dyes. It is also known that ionic liquids can dissolve significant amounts of dyes. Consequently, supramolecular ionic liquids gels could be highly efficient sorbents for dyes removal. This would also contribute to overcome the drawbacks associated with dye removal by liquid-liquid extraction with neat ionic liquids which would require large volumes of extractant and a more difficult separation of the phases. Herein we employed novel supramolecular ionic liquid gels based on diimidazolium salts bearing naturally occurring or biomass derived anions, to adsorb cationic and anionic dyes from wastewaters. We also carried out a detailed investigation of thermal, structural, morphological and rheological features of our gels to identify which of them are key in designing better sorbents for environmental remediation. The most effective gels showed fast and thorough removal of cationic dyes like Rhodamine B. These gels could also be reused up to 20 times without any loss in removal efficiency. Overall, our ionic gels outperform most of gel-based sorbents systems so far reported in literature. Copyright © 2018 Elsevier Inc. All rights reserved.

Optimization of pressurized liquid extraction of inositols from pine nuts (Pinus pinea L.).

PubMed

Ruiz-Aceituno, L; Rodríguez-Sánchez, S; Sanz, J; Sanz, M L; Ramos, L

2014-06-15

Pressurized liquid extraction (PLE) has been used for the first time to extract bioactive inositols from pine nuts. The influence of extraction time, temperature and cycles of extraction in the yield and composition of the extract was studied. A quadratic lineal model using multiple linear regression in the stepwise mode was used to evaluate possible trends in the process. Under optimised PLE conditions (50°C, 18 min, 3 cycles of 1.5 mL water each one) at 10 MPa, a noticeable reduction in extraction time and solvent volume, compared with solid-liquid extraction (SLE; room temperature, 2h, 2 cycles of 5 mL water each one) was achieved; 5.7 mg/g inositols were extracted by PLE, whereas yields of only 3.7 mg/g were obtained by SLE. Subsequent incubation of PLE extracts with Saccharomyces cerevisiae (37°C, 5h) allowed the removal of other co-extracted low molecular weight carbohydrates which may interfere in the bioactivity of inositols. Copyright © 2014 Elsevier Ltd. All rights reserved.

EXPERIMENTAL LIQUID METAL FUEL REACTOR

DOEpatents

Happell, J.J.; Thomas, G.R.; Denise, R.P.; Bunts, J.L. Jr.

1962-01-23

A liquid metal fuel nuclear fission reactor is designed in which the fissionable material is dissolved or suspended in a liquid metal moderator and coolant. The liquid suspension flows into a chamber in which a critical amount of fissionable material is obtained. The fluid leaves the chamber and the heat of fission is extracted for power or other utilization. The improvement is in the support arrangement for a segrnented graphite core to permit dif ferential thermal expansion, effective sealing between main and blanket liquid metal flows, and avoidance of excessive stress development in the graphite segments. (AEC)

Rational and Efficient Preparative Isolation of Natural Products by MPLC-UV-ELSD based on HPLC to MPLC Gradient Transfer.

PubMed

Challal, Soura; Queiroz, Emerson Ferreira; Debrus, Benjamin; Kloeti, Werner; Guillarme, Davy; Gupta, Mahabir Prashad; Wolfender, Jean-Luc

2015-11-01

In natural product research, the isolation of biomarkers or bioactive compounds from complex natural extracts represents an essential step for de novo identification and bioactivity assessment. When pure natural products have to be obtained in milligram quantities, the chromatographic steps are generally labourious and time-consuming. In this respect, an efficient method has been developed for the reversed-phase gradient transfer from high-performance liquid chromatography to medium-performance liquid chromatography for the isolation of pure natural products at the level of tens of milligrams from complex crude natural extracts. The proposed method provides a rational way to predict retention behaviour and resolution at the analytical scale prior to medium-performance liquid chromatography, and guarantees similar performances at both analytical and preparative scales. The optimisation of the high-performance liquid chromatography separation and system characterisation allows for the prediction of the gradient at the medium-performance liquid chromatography scale by using identical stationary phase chemistries. The samples were introduced in medium-performance liquid chromatography using a pressure-resistant aluminium dry load cell especially designed for this study to allow high sample loading while maintaining a maximum achievable flow rate for the separation. The method has been validated with a mixture of eight natural product standards. Ultraviolet and evaporative light scattering detections were used in parallel for a comprehensive monitoring. In addition, post-chromatographic mass spectrometry detection was provided by high-throughput ultrahigh-performance liquid chromatography time-of-flight mass spectrometry analyses of all fractions. The processing of all liquid chromatography-mass spectrometry data in the form of an medium-performance liquid chromatography x ultra high-performance liquid chromatography time-of-flight mass spectrometry matrix enabled an efficient localisation of the compounds of interest in the generated fractions. The methodology was successfully applied for the separation of three different plant extracts that contain many diverse secondary metabolites. The advantages and limitations of this approach and the theoretical chromatographic background that rules such as liquid chromatography gradient transfer are presented from a practical viewpoint. Georg Thieme Verlag KG Stuttgart · New York.

Pharmacokinetic Studies of Chinese Medicinal Herbs Using an Automated Blood Sampling System and Liquid Chromatography-mass Spectrometry.

PubMed

Wu, Yu-Tse; Wu, Ming-Tsang; Lin, Chia-Chun; Chien, Chao-Feng; Tsai, Tung-Hu

2012-01-01

The safety of herbal products is one of the major concerns for the modernization of traditional Chinese medicine, and pharmacokinetic data of medicinal herbs guide us to design the rational use of the herbal formula. This article reviews the advantages of the automated blood sampling (ABS) systems for pharmacokinetic studies. In addition, three commonly used sample preparative methods, protein precipitation, liquid-liquid extraction and solid-phase extraction, are introduced. Furthermore, the definition, causes and evaluation of matrix effects in liquid chromatography-mass spectrometry (LC/MS) analysis are demonstrated. Finally, we present our previous works as practical examples of the application of ABS systems and LC/MS for the pharmacokinetic studies of Chinese medicinal herbs.

Jasminum polyanthum Franch. as a natural source of (-)-methyl jasmonate: an alternative to the use of the synthetic standard.

PubMed

Blanch, Gracia Patricia; Flores, Gema; Caja, Maria del Mar; Ruiz del Castillo, Maria Luisa

2009-01-01

Methyl jasmonate (MJ) contains two chiral centres at C-3 and C-7 in its chemical structure, which implies that it can exist in four possible stereoisomeric forms, namely (+)-MJ, (-)-MJ, (+)-epiMJ and (-)-epiMJ. The absolute configuration of the two side chains of MJ affects the biological activity associated with this compound. To isolate pure (-)-MJ from a natural source, Jasminum polyanthum Franch., with the intention of increasing the knowledge about its biological properties, including its effect on the biosynthesis of plant metabolites. The method used was based on steam distillation extraction (SDE) as an extraction technique followed by high-performance liquid chromatography (HPLC) as a purification procedure. The HPLC flow-rate as well as the number of fractions accumulated were optimised to achieve the concentration and purity required. The employment of 0.3 mL/min as HPLC flow-rate and the accumulation of three HPLC fractions allowed the required enantiomeric purity (95%) and concentration (0.36 mg/L in each HPLC fraction) to efficiently obtain (-)-methyl jasmonate from Jasminum polyanthum Franch. to be achieved. The approach proposed may enable the properties and effect of pure (-)-MJ on plant responses to be studied. The use of a natural source to obtain (-)-MJ is presented as an alternative to the enantioselective synthesis and enantiomeric resolution from the standard racaemic mixture.

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.

PubMed

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.

REMOVAL OF URANIUM FROM ORGANIC LIQUIDS

DOEpatents

Vavalides, S.P.

1959-08-25

A process is described for recovering small quantities of uranium from organic liquids such as hydrocarbon oils. halogen-substituted hydrocarbons, and alcohols. The organic liquid is contacted with a comminuted alkaline earth hydroxide, calcium hydroxide particularly, and the resulting uranium-bearing solid is separated from the liquid by filtration. Uranium may then be recovered from the solid by means of dissolution in nitric acid and conventional extraction with an organic solvent such as tributyl phosphate.

Gas-liquid chromatographic and gas-liquid-mass spectometric determination of fenvalerate and permethrin residues in grasshoppers and duck tissue samples

USGS Publications Warehouse

Reichel, W.L.; Kolbe, E.J.; Stafford, C.J.

1981-01-01

A procedure is described for determining fenvalerate and permethrin residues in grasshoppers and duck tissues. Samples are Soxhlet-extracted with hexane and cleaned up by gel permeation chromatography with an in-line alumina column. Samples are analyzed by gas-liquid chromatography with electron capture detection, and confirmed by gas-liquid chromatography-mass spectrometry. The average recovery from fortified tissues was 97%.

Application of ionic liquids based microwave-assisted simultaneous extraction of carnosic acid, rosmarinic acid and essential oil from Rosmarinus officinalis.

PubMed

Liu, Tingting; Sui, Xiaoyu; Zhang, Rongrui; Yang, Lei; Zu, Yuangang; Zhang, Lin; Zhang, Ying; Zhang, Zhonghua

2011-11-25

An ionic liquid based microwave-assisted simultaneous extraction and distillation (ILMSED) method has been developed for the effective extraction of carnosic acid (CA), rosmarinic acid (RA) and essential oil (EO) from Rosmarinus officinalis. A series of 1-alkyl-3-methylimidazolium ionic liquids differing in composition of anion and cation were evaluated for extraction yield in this work. The results obtained indicated that the anions and cations of ionic liquids had influences on the extraction of CA and RA, 1.0M 1-octyl-3-methylimidazolium bromide ([C8mim]Br) solution was selected as solvent. In addition, the ILMSED procedures for the three target ingredients were optimized and compared with other conventional extraction techniques. ILMSED gave the best result due to the highest extraction yield within the shortest extraction time for CA and RA. The novel process developed offered advantages in term of yield and selectivity of EO and shorter isolation time (20 min in comparison of 4h of hydrodistillation), and provides a more valuable EO (with high amount of oxygenated compounds). The microstructures and chemical structures of rosemary samples before and after extraction were also investigated. Moreover, the proposed method was validated by the stability, repeatability and recovery experiments. The results indicated that the developed ILMSED method provided a good alternative for the both extraction of non-volatile compounds (CA and RA) and EO from rosemary as well as other herbs. Copyright © 2011 Elsevier B.V. All rights reserved.

PYROMETALLURGICAL METHOD

DOEpatents

Nelson, P.A.

1961-07-18

The liquid--liquid extraction of plutonium by magnesium from uranium or uranium--chromium alloy is described. Calcium is added to magnesium in about eutectic proportions, which results in a purer plutonium.

Benzyl and Methyl Fatty Hydroxamic Acids Based on Palm Kernel Oil as Chelating Agent for Liquid-Liquid Iron(III) Extraction

PubMed Central

Haron, Md Jelas; Jahangirian, Hossein; Silong, Sidik; Yusof, Nor Azah; Kassim, Anuar; Rafiee-Moghaddam, Roshanak; Mahdavi, Behnam; Peyda, Mazyar; Abdollahi, Yadollah; Amin, Jamileh

2012-01-01

Liquid-liquid iron(III) extraction was investigated using benzyl fatty hydroxamic acids (BFHAs) and methyl fatty hydroxamic acids (MFHAs) as chelating agents through the formation of iron(III) methyl fatty hydroxamate (Fe-MFHs) or iron(III) benzyl fatty hydroxamate (Fe-BFHs) in the organic phase. The results obtained under optimized conditions, showed that the chelating agents in hexane extract iron(III) at pH 1.9 were realized effectively with a high percentage of extraction (97.2% and 98.1% for MFHAs and BFHAs, respectively). The presence of a large amount of Mg(II), Ni(II), Al(III), Mn(II) and Co(II) ions did affect the iron(III) extraction. Finally stripping studies for recovering iron(III) from organic phase (Fe-MFHs or Fe-BFHs dissolved in hexane) were carried out at various concentrations of HCl, HNO3 and H2SO4. The results showed that the desired acid for recovery of iron(III) was 5 M HCl and quantitative recovery of iron(III) was achieved from Fe(III)-MFHs and Fe(III)-BFHs solutions in hexane containing 5 mg/L of Fe(III). PMID:22408444

Estrogens determination in wastewater samples by automatic in-syringe dispersive liquid-liquid microextraction prior silylation and gas chromatography.

PubMed

González, Alba; Avivar, Jessica; Cerdà, Víctor

2015-09-25

A new procedure for the extraction, preconcentration and simultaneous determination of the estrogens most used in contraception pharmaceuticals (estrone, 17β-estradiol, estriol, and 17α-ethynylestradiol), cataloged as Contaminants of Emergent Concern by the Environmental Protection Agency of the United States (US-EPA), is proposed. The developed system performs an in-syringe magnetic stirring-assisted dispersive liquid-liquid microextraction (in-syringe-MSA-DLLME) prior derivatization and gas chromatography (GC-MS). Different extraction (carbon tetrachloride, ethyl acetate, chloroform and trichloroethylene) and disperser solvents (acetone, acetonitrile and methanol) were tested. Chloroform and acetone were chosen as extraction and disperser solvent, respectively, as they provided the best extraction efficiency. Then, a multivariate optimization of the extraction conditions was carried out. Derivatization conditions were also studied to ensure the conversion of the estrogens to their respective trimethylsilyl derivatives. Low LODs and LOQs were achieved, i.e. between 11 and 82ngL(-1), and 37 and 272ngL(-1), respectively. Good values for intra and inter-day precision were obtained (RSDs≤7.06% and RSD≤7.11%, respectively). The method was successfully applied to wastewater samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Optimization and development of a SPE-HPLC-UV method to determine astaxanthin in Saccharina japonica.

PubMed

Zhou, Jun; Bi, Wentao; Row, Kyung Ho

2011-04-01

An effective and accurate method including extraction, saponification, and separation was developed to determine astaxanthin (AX) in Saccharina japonica. The optimal extraction conditions with different solvents were investigated. 29.30 μg/g of AX was extracted from dry Saccharina japonica powder by solvent. After subsequent saponification, the extracted amount of AX was increased to 37.26 μg/g. Furthermore, 3 different ionic liquid-based silicas were prepared as sorbents for the solid phase extraction of AX from the extract. By comparing the adsorption isotherms of AX on different ionic liquid-based silicas, suitable sorbent was successfully selected and applied for separation of AX from extract. Astaxanthin, in 3 main forms (free, monoesters, and diesters), can be obtained from marine plants and animals. By extraction with subsequent saponification, the astaxanthin was extracted from Saccharina japonica. And then, ionic liquid-based silicas were used to separate the astaxanthin from the extract solution. This method can be widely applied for determination, or even industrial separation and purification of astaxanthin from many other algae.

Ultra-Trace Analysis of Nine Macrolides, including Tulathromycin A (Draxxin), in Edible Animal Tissues with Mini-Column Liquid Chromatography Tandem Mass Spectrometry

USDA-ARS?s Scientific Manuscript database

Analysis of 9 macrolides is presented, including tulathromycin A (Draxxin), in beef, poultry and pork muscle with a simple multi-residue extraction and analysis method using high performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry. The extraction method inv...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blay, J.A.

The problem of the determination of micro-amounts of uranium in aqueous and organic phases in liquid-liquid extraction processes, original ones, and extraction residues was solved by a chromatographic separation of the uranium by means of columns of activated cellulose and further spectrophotometric evaluation using the thiocyanate complex in aqueous medium. The usable range is 5 to 200 mu g.

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

PubMed

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.

Accurate Quantitation and Analysis of Nitrofuran Metabolites, Chloramphenicol, and Florfenicol in Seafood by Ultrahigh-Performance Liquid Chromatography-Tandem Mass Spectrometry: Method Validation and Regulatory Samples.

PubMed

Aldeek, Fadi; Hsieh, Kevin C; Ugochukwu, Obiadada N; Gerard, Ghislain; Hammack, Walter

2018-05-23

We developed and validated a method for the extraction, identification, and quantitation of four nitrofuran metabolites, 3-amino-2-oxazolidinone (AOZ), 3-amino-5-morpholinomethyl-2-oxazolidinone (AMOZ), semicarbazide (SC), and 1-aminohydantoin (AHD), as well as chloramphenicol and florfenicol in a variety of seafood commodities. Samples were extracted by liquid-liquid extraction techniques, analyzed by ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), and quantitated using commercially sourced, derivatized nitrofuran metabolites, with their isotopically labeled internal standards in-solvent. We obtained recoveries of 90-100% at various fortification levels. The limit of detection (LOD) was set at 0.25 ng/g for AMOZ and AOZ, 1 ng/g for AHD and SC, and 0.1 ng/g for the phenicols. Various extraction methods, standard stability, derivatization efficiency, and improvements to conventional quantitation techniques were also investigated. We successfully applied this method to the identification and quantitation of nitrofuran metabolites and phenicols in 102 imported seafood products. Our results revealed that four of the samples contained residues from banned veterinary drugs.

Liquid-liquid extraction/headspace/gas chromatographic/mass spectrometric determination of benzene, toluene, ethylbenzene, (o-, m- and p-)xylene and styrene in olive oil using surfactant-coated carbon nanotubes as extractant.

PubMed

Carrillo-Carrión, Carolina; Lucena, Rafael; Cárdenas, Soledad; Valcárcel, Miguel

2007-11-09

BTEX-S compounds are widely distributed in the environment and can be present in different foodstuffs, including olive oil. Taking into account the risks of the exposure to these compounds, analytical methods for their determination in different matrices are mandatory. In this paper, the use of surfactant-coated multiwalled carbon nanotubes as additive in liquid-liquid extraction is applied for the determination of single-ring aromatic compounds in olive oil samples. After sample treatment, the aqueous extracts are subsequently analyzed by headspace/gas chromatography/mass spectrometry allowing the determination of BTEX-S within ca. 15 min. Each stage of the proposed LLE/HS/GC/MS configuration involves a selectivity enhancement avoiding the interference of other compounds of the sample matrix. Limits of detection were in the range 0.25 ng mL(-1) (obtained for ethylbenzene) and 0.43 ng mL(-1) (for benzene). The repeatability of the proposed method expressed as RSD varied between 1.9% (styrene) and 3.3% (benzene) (n=11).

Evaluation of transfer rates of multiple pesticides from green tea into infusion using water as pressurized liquid extraction solvent and ultra-performance liquid chromatography tandem mass spectrometry.

PubMed

Chen, Hongping; Pan, Meiling; Liu, Xin; Lu, Chengyin

2017-02-01

Pesticide residues could be transferred from tea into its infusion and by-products, and subsequently consumed by humans. Extra extraction conditions may induce more pesticide leaching into the infusion and by-products of tea and cause greater damage to humans. The aim of this study is to evaluate the infusion of multiple pesticides from green tea into hot water via pressurized liquid extraction. The results showed that pesticides in spiked samples generally have higher leaching (0.8-45.0%) than those in the positive samples. There was a marked rise of transfer rates when water solubility increased from 20mgL(-1) to 450mgL(-1) and LogKow decreased from 6 to 4. All pesticides had more leaching into hot water using pressurized liquid extraction than traditional tea brewing. This study helps in risk assessment of pesticide residues and in the formulation of maximum residue levels (MRLs) in tea and its by-products. Copyright © 2016 Elsevier Ltd. All rights reserved.

Development of Hollow-Fiber Liquid-Phase Microextraction Method for Determination of Urinary trans,trans-Muconic Acid as a Biomarker of Benzene Exposure

PubMed Central

Ghamari, Farhad; Bahrami, Abdulrahman; Yamini, Yadollah; Shahna, Farshid Ghorbani; Moghimbeigi, Abbas

2016-01-01

For the first time, hollow-fiber liquid-phase microextraction combined with high-performance liquid chromatography–ultraviolet was used to extract trans,trans-muconic acid, in urine samples of workers who had been exposed to benzene. The parameters affecting the metabolite extraction were optimized as follows: the volume of sample solution was 11 mL with pH 2, liquid membrane containing dihexyl ether as the supporter, 15% (w/v) of trioctylphosphine oxide as the carrier, the time of extraction was 120 minutes, and stirring rate was 500 rpm. Organic phase impregnated in the pores of a hollow fiber was extracted into 24 µL solution of 0.05 mol L−1 Na2CO3 located inside the lumen of the fiber. Under optimized conditions, a high enrichment factor of 153–182 folds, relative recovery of 83%–92%, and detection limit of 0.001 µg mL−1 were obtained. The method was successfully applied to the analysis of ttMA in real urine samples. PMID:27660405