WorldWideScience

Sample records for bead-injection lab-on-valve hyphenated

  1. Determination of salivary cotinine through solid phase extraction using a bead-injection lab-on-valve approach hyphenated to hydrophilic interaction liquid chromatography.

    Science.gov (United States)

    Ramdzan, Adlin N; Barreiros, Luísa; Almeida, M Inês G S; Kolev, Spas D; Segundo, Marcela A

    2016-01-15

    Cotinine, the first metabolite of nicotine, is often used as a biomarker in the monitoring of environmental tobacco smoke (ETS) exposure due to its long half-life. This paper reports on the development of an at-line automatic micro-solid phase extraction (μSPE) method for the determination of salivary cotinine followed by its analysis via hydrophilic interaction liquid chromatography (HILIC). The SPE methodology is based on the bead injection (BI) concept in a mesofluidic lab-on-valve (LOV) flow system to automatically perform all SPE steps. Three commercially available reversed-phase sorbents were tested, namely, Oasis HLB, Lichrolut EN and Focus, and the spherically shaped sorbents (i.e., Oasis HLB and Focus) provided better packing within the SPE column and hence higher column efficiency. An HILIC column was chosen based on its potential for achieving higher sensitivity and better retention of polar compounds such as cotinine. The method uses an isocratic program with acetonitrile:100mM ammonium acetate buffer, pH 5.8 in 95:5 v/v ratio as the mobile phase at a flow rate of 1.0 mL min(-1). Using this approach, the linear calibration range was from 10 to 1000 ng which corresponded to 5-500 μg L(-1). The corresponding μSPE-BI-LOV system was proven to be reliable in the handing and analysis of viscous biological samples such as saliva, achieving a sampling rate of 6h(-1) and a limit of detection and quantification of 1.5 and 3μgL(-1), respectively. PMID:26747690

  2. Hyphenating multisyringe flow injection lab-on-valve analysis with atomic fluorescence spectrometry for on-line bead injection preconcentration and determination of trace levels of hydride-forming elements in environmental samples.

    Science.gov (United States)

    Long, Xiangbao; Miró, Manuel; Hansen, Elo Harald; Estela, José Manuel; Cerdà, Víctor

    2006-12-15

    In this work the third generation of flow injection analysis, that is, the so-called micro-lab-on-valve (microLOV) approach, is proposed for the first time for the separation, preconcentration, and monitoring of metalloids as hyphenated with atomic fluorescence spectrometry (AFS). This was made feasible by interfacing the micromachined LOV-module with AFS by a multisyringe flowing stream network for on-line postcolumn derivatization of the eluate aimed at generation of hydride species. The potential of this new hyphenated technique for environmental assays was ascertained via determination of ultratrace level concentrations of total inorganic arsenic in freshwater. Employing quantitative preoxidation of As(III) to As(V) in the samples by means of permanganate, the method involves preconcentration of arsenate at pH 10 on a renewable anion exchanger, namely, Q-Sepharose, packed in a LOV microcolumn. The analyte species is afterward stripped out and concurrently prereduced by a 300 microL eluent plug containing 6 mol L(-)1 HCl and 10% KI. The eluate is downstream merged with a metered volume of sodium tetrahydroborate (0.3% w/v) for generation of arsine, which is subsequently quantified by AFS. The flow system facilitates on-column reduction of the retained arsenic with no need for application of programmable stopped flow. Yet, the high concentration of reductant and extreme pH conditions for elution hinder the sorbent to be reused due to gradual deactivation of the functional moieties, so that maximum benefit can be taken from the application of the bead renewable strategy. The proposed procedure is characterized by a high tolerance to metal species and interfering hydride-forming elements. In fact, ratios of Se(IV) to As < or = 5000 and Sb(V) to As < or = 500 are tolerated at the 10% interference level. Under the optimized experimental conditions, a detection limit (3sigma) of 0.02 ng mL(-1) As, a dynamic linear range of 0.05-2.0 ng mL(-1) As (by tailoring the AFS

  3. Hyphenating multisyringe flow injection lab-on-valve analysis with atomic fluorescence spectrometry for on-line bead-injection preconcentration and determination of trace levels of hydride-forming elements in environmental samples

    DEFF Research Database (Denmark)

    Long, Xiangbao; Miró, Manuel; Hansen, Elo Harald; Estela, José Manuel; Cerdà, Victor

    2006-01-01

    determination of ultratrace level concentrations of total inorganic arsenic in freshwater. Employing quantitative preoxidation of As(III) to As(V) in the samples by means of permanganate, the method involves the preconcentration of arsenate at pH 10 on a renewable anion exchanger, namely Q-Sepharose, packed in...... for the bead-injection mode whenever the loading sample volume was affixed at 3.0 mL. The reliability and accuracy of the automated procedure was ascertained by determining total inorganic arsenic in both spiked environmental waters and certified reference materials of variable matrix complexity (TMDA...... 10% interference level. Under the optimized experimental conditions, a detection limit (3σ) of 0.02 ng mL-1 As, a dynamic linear range of 0.05-2.0 ng mL-1 As (by tailoring the AFS gain), an enrichment factor of 8.8 for arsenate, and a precision better than 6.0% at the 0.1 ng mL-1 level were obtained...

  4. Universal approach for selective trace metal determinations via sequential injection-bead injection-lab-on-valve using renewable hydrophobic bead surfaces as reagent carriers

    DEFF Research Database (Denmark)

    Long, Xiangbao; Miró, Manuel; Hansen, Elo Harald

    2005-01-01

    A new concept is presented for selective and sensitive determination of trace metals via electrothermal atomic absorption spectrometry (ETAAS) based on the principle of bead injection (BI) with renewable reversed-phase surfaces in a sequential injection-lab-on-valve (SI-LOV) mode. The methodology...

  5. Bead Injection Extraction Chromatography using High-capacity Lab-on-Valve as a Front End to Inductively Coupled Plasma Mass Spectrometry for Rapid Urine Radiobioassay

    DEFF Research Database (Denmark)

    Qiao, Jixin; Hou, Xiaolin; Roos, Per;

    2013-01-01

    A novel bead injection (BI) extraction chromatographic microflow system exploiting high-capacity lab-on-valve (LOV) platform coupled with inductively coupled plasma mass spectrometric detection is developed for rapid and automated determination of plutonium in human urine. A microconduit (1 m......L) incorporated within the LOV processing unit is loaded on-line with a metered amount of disposable extraction chromatographic resin (up to 330 mg of TEVA) through programmable beads transport. Selective capture and purification of plutonium onto the resin beads is then performed by pressure driven flow after.......319 ± 0.004 g, n=5). The chemical yields of plutonium were averagely better than 90% under the optimal experimental conditions and the entire analytical procedure could be accomplished within a short timeframe (

  6. Universal approach for selective trace metal determinations via sequential injection-bead injection-lab-on-valve using renewable hydrophobic bead surfaces as reagent carriers

    DEFF Research Database (Denmark)

    Long, Xiangbao; Miró, Manuel; Hansen, Elo Harald

    2005-01-01

    A new concept is presented for selective and sensitive determination of trace metals via electrothermal atomic absorption spectrometry (ETAAS) based on the principle of bead injection (BI) with renewable reversed-phase surfaces in a sequential injection-lab-on-valve (SI-LOV) mode. The methodology...... involves the use of poly(styrene-divinylbenzene) beads containing pendant octadecyl moieties (C18-PS/DVB), which are preimpregnated with a selective organic metal chelating agent prior to the automatic manipulation of the beads in the microbore conduits of the LOV unit. By adapting this approach, the...... immobilization of the most suitable chelating agent can be effected irrespective of the kinetics involved, optimal reaction conditions can be used for implementing the chelating reaction of the target metal analyte with the immobilized reagent, and an added degree of freedom is offered in selecting the most...

  7. Sequential injection/bead injection lab-on-valve schemes for on-line solid phase extraction and preconcentration of ultra-trace levels of heavy metals with determination by ETAAS and ICPMS

    DEFF Research Database (Denmark)

    Wang, Jianhua; Hansen, Elo Harald; Miró, Manuel

    2003-01-01

    are focused on the applications of SI-BI-LOV protocols for on-line microcolumn based solid phase extraction of ultra-trace levels of heavy metals, employing the so-called renewable surface separation and preconcentration manipulatory scheme. Two types of sorbents have been employed as packing material......This communication presents an overview of the state-of-the-art of the exploitation of sequential injection (SI)-bead injection (BI)-lab-on-valve (LOV) schemes for automatic on-line sample pre-treatments interfaced with ETAAS and ICPMS detection as conducted in the authors' group. The discussions...

  8. Multisyringe flow injection lab-on-valve systems coupled to hydride generation atomic fluorescence spectrometry for on-line bead-injection preconcentration and determination of total inorganic arsenic in environmental waters

    DEFF Research Database (Denmark)

    Long, Xiangbao; Miró, Manuel; Hansen, Elo Harald;

    and 10% KI. The eluate merges downstream with a defined plug of sodium tetrahydroborate (0.3% w/v) for generation of arsine, which is subsequently quantified by AFS. An oxidation agent, namely 2x10-6 M potassium permanganate, was employed for the quantitative oxidation of As(III) to As(V) in the samples......In this work, the third generation of flow injection analysis, that is, the so-called micro-Lab-on-Valve (LOV) approach, is hyphenated for the first time to atomic fluorescence spectrometry (AFS) for the separation, preconcentration and monitoring of hydride forming elements. A multisyringe flowing...... stream network is assembled for accurate handling of solutions and on-line post column derivatization of the eluate for the generation of the volatile species. The potential of the new hyphenated technique for environmental assays was ascertained via the determination of ultratrace levels of total...

  9. Sequential injection-bead injection-lab-on-valve schemes for on-line solid phase extraction and preconcentration of ultra-trace levels of heavy metals with determination by electrothermal atomic absorption spectrometry and inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    This communication presents an overview of the state-of-the-art of the exploitation of sequential injection (SI)-bead injection (BI)-lab-on-valve (LOV) schemes for automatic on-line sample pre-treatments interfaced with ETAAS and ICPMS detection as conducted in the authors' group. The discussions are focused on the applications of SI-BI-LOV protocols for on-line microcolumn based solid phase extraction of ultra-trace levels of heavy metals, employing the so-called renewable surface separation and preconcentration manipulatory scheme. Two types of sorbents have been employed as packing material, that is, the hydrophilic SP Sephadex C-25 cation exchange and iminodiacetate based Muromac A-1 chelating resins, and the hydrophobic poly(tetrafluoroethylene) (PTFE) and poly(styrene-divinylbenzene) copolymer alkylated with octadecyl groups (C18-PS/DVB). Using ETAAS as detection device, the easy-to-handle hydrophilic renewable reactors hold the features of improved R.S.D.s and LODs as compared to those operated in the conventional, permanent mode, in addition to the elimination of flow resistance. The hydrophobic columns fall into two categories, that is, the renewable one packed with C18-PS/DVB beads entails analogous R.S.D.s and LODs with respect to the conventional approach, while those with PTFE beads result in slightly inferior R.S.D.s and LODs by similar comparison, yet offering a wider dynamic range than when using an external permanent column. Moreover, the hydrophilic materials result in much higher enrichment of the analyte than the hydrophobic ones, although PTFE is the packing material that exhibits the best retention efficiency

  10. An automatic micro-sequential injection bead injection lab-on-valve (muSI-BI-LOV) assembly for speciation analysis of ultra trace levels of Cr(III) and Cr(VI) incorporating on-line chemical reduction and employing detection by electrothermal atomic absorption spectrometry (ETAAS)

    DEFF Research Database (Denmark)

    Long, Xiangbao; Miró, Manuel; Hansen, Elo Harald

    2005-01-01

    A novel, miniaturized micro-sequential injection Lab-on-Valve (muSI-LOV) system hyphenated with electrothermal atomic absorption spectrometry (ETAAS) is proposed for the automatic preconcentration and speciation analysis of Cr(III) and Cr(VI) utilizing solid-phase extraction on hydrophilic...

  11. A Universal Approach for Selective Trace Metal Determinations via Sequential Injection-Bead Injection-Lab-on-Valve (SI-BI-LOV) Using Renewable Reagent-loaded Hydrophobic Beads

    DEFF Research Database (Denmark)

    Long, Xiangbao; Miró, Manuel; Hansen, Elo Harald

    A new sample pretreatment approach is presented for selective and sensitive determination of trace metals via electrothermal atomic absorption spectrometry (ETAAS) based on the principle of bead injection (BI) with renewable reagent-loaded hydrophobic beads in a Sequential Injection...

  12. Exploiting the bead-injection approach in the integrated sequential injection Lab-on-Valve format using hydrophobic packing materials for on-line matrix removal and preconcentration of trace levels of cadmium in environmental and biological samples via formation of non-charged chelates prior to ETAAS detection

    DEFF Research Database (Denmark)

    Miró, Manuel; Jonczyk, Sylwia; Wang, Jianhua;

    2003-01-01

    The concept of renewable microcolumns within the conduits of an automated single injection lab-on-valve system was exploited in a sorption/elution fashion using sorbents of hydrophobic nature. The scheme's practical applicability was demonstrated for the electrothermal atomic absorption...... spectrometry determination of trace level concentrations of cadmium in complex matrices. Statistical comparisons between the proposed procedure and certified values revealed no significant differences at the 95% confidence level....

  13. On-line dynamic extraction and automated determination of readily bioavailable hexavalent chromium in solid substrates using micro-sequential injection bead-injection lab-on-valve hyphenated with electrothermal atomic absorption spectrometry

    DEFF Research Database (Denmark)

    Long, Xiangbao; Miró, Manuel; Hansen, Elo Harald

    2006-01-01

    ). The effect of simulated acidic rain on the accessibility of chromate forms for plant uptake was also investigated. The proposed approach offers several advantages over conventional speciation/fractionation protocols in the batch mode, including immediate separation with concomitant preconcentration of...

  14. On-line dynamic extraction and automated determination of readily bioavailable hexavalent chromium in solid substrates using micro-sequential injection bead-injection lab-on-valve hyphenated with electrothermal atomic absorption spectrometry

    DEFF Research Database (Denmark)

    Long, Xiangbao; Miró, Manuel; Hansen, Elo Harald

    2006-01-01

    ). The effect of simulated acidic rain on the accessibility of chromate forms for plant uptake was also investigated. The proposed approach offers several advantages over conventional speciation/fractionation protocols in the batch mode, including immediate separation with concomitant preconcentration...

  15. Hyphenating multisyringe flow injection lab-on-valve analysis with atomic fluorescence spectrometry for on-line bead-injection preconcentration and determination of trace levels of hydride-forming elements in environmental samples

    DEFF Research Database (Denmark)

    Long, Xiangbao; Miró, Manuel; Hansen, Elo Harald;

    2006-01-01

    determination of ultratrace level concentrations of total inorganic arsenic in freshwater. Employing quantitative preoxidation of As(III) to As(V) in the samples by means of permanganate, the method involves the preconcentration of arsenate at pH 10 on a renewable anion exchanger, namely Q-Sepharose, packed in...... quantified by AFS. The flow system facilitates on-column reduction of the retained arsenic with no need for application of programmable stopped-flow. Yet, the high concentration of reductant and extreme pH conditions for elution hinder the sorbent to be re-used due to the gradual deactivation of the...... functional moieties, so that maximum benefit can be taken from the application of the bead renewal strategy. The proposed procedure is characterized by a high tolerance to metal species and interfering hydride forming elements. In fact, ratios of Se(IV) to As ≤ 5000 and Sb(V) to As ≤ 500 are tolerated at the...

  16. Sequential injection lab-on-valve: the third generation of flow injection analysis

    DEFF Research Database (Denmark)

    Wang, Jianhua; Hansen, Elo Harald

    2003-01-01

    Termed the third generation of flow injection analysis, sequential injection (SI)-lab-on-valve (LOV) has specific advantages and allows novel, unique applications - not least as a versatile front end to a variety of detection techniques. This review presents snd discusses progress to date of the SI......-LOV approach as well as its applications in the automation and micro-miniaturization of on-line sample pre-treatment. Special emphasis is placed on using SI-LOV in conjunction with bead injection (BI) for on-line separation and pre-concentration of ultra-trace levels of metals by exploiting the renewable micro......-column approach. With detection by ETAAS and ICP-MS, it is shown, as illustrated by recent results in the authors’ laboratory, that this methodology eliminates the problems encountered in conventional on-line column pre-concentration systems, improves the overall operational efficiency and yields the robustness...

  17. Fully automated lab-on-valve-multisyringe flow injection analysis-ICP-MS system: An effective tool for fast, sensitive and selective determination of thorium and uranium at environmental levels exploiting solid phase extraction

    OpenAIRE

    Avivar, Jessica; Ferrer, Laura; Casas, Montserrat; Cerdà, Víctor

    2012-01-01

    An on-line solid-phase extraction method linked to inductively coupled mass spectrometry (ICP-MS) has been developed for the determination of low levels of uranium and thorium in environmental samples. The hyphenation of lab-on-valve (LOV) and multisyringe flow injection analysis (MSFIA), coupled to an ICP-MS, allows the simultaneous determination of thorium and uranium in different types of environmental sample matrices achieving high selectivity and sensitivity levels. On-line separation an...

  18. Interfacing microfluidic handling with spectroscopic detection for real-life applications via the lab-on-valve platform: A review

    DEFF Research Database (Denmark)

    Hansen, Elo Harald; Miró, Manuel

    2008-01-01

    . Illustrated via selected representative examples, this review presents and discusses the current state of the art in implementing miniaturised and automated sample treatments for environmental and biochemical assays via microfluidic systems exploiting the lab-on-a-valve (LOV) platform in hyphenation with......One of the current needs within the analytical spectrometric community is the development of straightforward and cost-effective, yet rugged, sample processing procedures aimed at precluding both spectroscopic and non-spectroscopic matrix interferences while fostering concomitant sample enrichment...... implementation of on-line unit operations at will encompassing not merely the introduction of minute, well-defined volumes of sample followed by chemical derivatization, but the potential for accommodation of solid-phase extraction, hydride/vapour generation, precipitation/coprecipitation and bead injection...

  19. Determination of Low Level Concentrations of Metals by Means of Sequential Injection (SI) and Lab-on-Valve (LOV) Methodologies

    DEFF Research Database (Denmark)

    Hansen, Elo Harald; Miró, Manuel; Petersen, Roongrat

    In recent years sequential injection (SI) analysis and Lab-on-Valve (LOV) approaches have proven themselves as powerful and versatile front ends to implement suitable pre-treatment procedures (separation and pre-concentration) for the assay of low concentrations of metals, as amply reflected....../emission spectrometry (FAAS, ETAAS, ICP-AES, ICP-MS). The lecture will initially give an overview of various automated alternatives for facilitating appropriate SI/LOV-separation and pre-concentration schemes of metals in liquid samples, including examples of solid-phase extraction with permanent columns or renewable...

  20. Determination of Low Level Concentrations of Metals by Means of Sequential Injection (SI) and Lab-on-Valve (LOV) Methodologies

    DEFF Research Database (Denmark)

    Hansen, Elo Harald

    In recent years sequential injection (SI) analysis and Lab-on-Valve (LOV) approaches have proven themselves as powerful and versatile front ends to implement suitable pre-treatment procedures (separation and pre-concentration) for the assay of low concentrations of metals, as amply reflected....../emission spectrometric devices such as FAAS, ETAAS, AFS, ICP-AES, and ICP-MS. While earlier separation and pre-concentration schemes of metals in liquid samples primarily have been centred on the use solvent extraction, or precipitate/(co)-precipitate collection in incorporated knotted reactors, or permanent columns...

  1. Extraction and preconcentration of trace levels of cobalt using functionalized magnetic nanoparticles in a sequential injection lab-on-valve system with detection by electrothermal atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Graphical abstract: An approach to performing extraction and preconcentration employing functionalized magnetic particles for the determination of cobalt in the sequential injection lab-on-valve system using detection by electrothermal atomic absorption spectrometry. Highlights: ► New SPE method for cobalt separation/preconcentration was reported. ► Functionalized magnetic nanoparticles were used as adsorbent. ► Extraction, elution, and detection procedures were performed in the LOV system. ► This automatic extraction technique provided a good platform for metal analysis. - Abstract: A new approach to performing extraction and preconcentration employing functionalized magnetic nanoparticles for the determination of trace metals is presented. Alumina-coated iron oxide nanoparticles were synthesized and used as the solid support. The nanoparticles were functionalized with sodium dodecyl sulfate and used as adsorbents for solid phase extraction of the analyte. Extraction, elution, and detection procedures were performed sequentially in the sequential injection lab-on-valve (SI-LOV) system followed by electrothermal atomic absorption spectrometry (ETAAS). Mixtures of hydrophobic analytes were successfully extracted from solution using the synthesized magnetic adsorbents. The potential use of the established scheme was demonstrated by taking cobalt as a model analyte. Under the optimal conditions, the calibration curve showed an excellent linearity in the concentration range of 0.01–5 μg L−1, and the relative standard deviation was 2.8% at the 0.5 μg L−1 level (n = 11). The limit of detection was 6 ng L−1 with a sampling frequency of 18 h−1. The present method has been successfully applied to cobalt determination in water samples and two certified reference materials.

  2. Evaluation of a novel PTFE material for separation and preconcentration of trace levels of metal ions in sequential injection (SI) and sequential injection lab-on-valve (SI-LOV) systems interfaced with detection by ETAAS

    DEFF Research Database (Denmark)

    Long, Xiangbao; Chomchoei, Roongrat; Gała, Piotr;

    and in a sequential injection lab-on-valve (SI-LOV) system. Employed for the determination of cadmium(II), complexed with diethyldithiophosphate (DDPA), and detection by electrothermal atomic absorption spectrometry (ETAAS), its performance was compared to that of a previously used material, Aldrich...

  3. Determination of trace metal ions via on-line separation and preconcentration by means of chelating Sepharose beads in a sequential injection lab-on-valve (SI-LOV) system coupled to electrothermal atomic absorption spectrometric detection

    DEFF Research Database (Denmark)

    Long, Xiangbao; Hansen, Elo Harald; Miró, Manuel

    2005-01-01

    The analytical performance of an on-line sequential injection lab-on-valve (SI-LOV) system using chelating Sepharose beads as sorbent material for the determination of ultra trace levels of Cd(II), Pb(II) and Ni(II) by electrothermal atomic absorption spectrometry (ETAAS) is described and discussed...

  4. A green analytical method for rapid determination of pectin degree of esterification using micro sequential injection lab-on-valve system.

    Science.gov (United States)

    Naghshineh, Mahsa; Larsen, Jan; Georgiou, Constantinos; Olsen, Karsten

    2016-08-01

    A novel method for automated determination pectin degree of esterification (DE) using micro sequential injection lab-on-valve (μSI-LOV) system is developed. A face-centered central composite response surface methodology (RSM) was used to optimise system parameters. A calibration graph for determination of non-esterified galacturonic acid (GalA) content in pectin solutions with linear range of 0.08-0.34% (w/v) and the limit of detection (LOD) of 0.057% (w/v) under optimal condition was achieved. The difference between concentrations (w/v, %) of total GalA and non-esterified GalA was applied to estimate DE (%) of pectin samples. Results indicated a good agreement (tstat

  5. An automatic micro-sequential injection bead injection lab-on-valve (muSI-BI-LOV) assembly for speciation analysis of ultra trace levels of Cr(III) and Cr(VI) incorporating on-line chemical reduction and employing detection by electrothermal atomic absorption spectrometry (ETAAS)

    DEFF Research Database (Denmark)

    Long, Xiangbao; Miró, Manuel; Hansen, Elo Harald

    2005-01-01

    and physical conditions, the flow system, by using a total sample loading volume of 3.6 mL, featured retention efficiencies for Cr(III) as high as 86%, and preconcentration factors of 62 and 42 and detection limits (3s) of 0.010 and 0.020 mug L-1 for Cr(III) and Cr(VI), respectively, The relative...... unit. Following quantification of the native Cr(III) content, the Cr(III) generated from Cr(VI) plus the original Cr(III) are subjected to the same separation/preconcentration/elution procedure. All sample manipulations are controlled automatically by the integrated software. Under optimized chemical...

  6. Determination of trace zinc in seawater by coupling solid phase extraction and fluorescence detection in the Lab-On-Valve format.

    Science.gov (United States)

    Grand, Maxime M; Chocholouš, Petr; Růžička, Jarda; Solich, Petr; Measures, Christopher I

    2016-06-01

    By virtue of their compactness, long-term stability, minimal reagent consumption and robustness, miniaturized sequential injection instruments are well suited for automation of assays onboard research ships. However, in order to reach the sensitivity and limit of detection required for open-ocean determinations of trace elements, it is necessary to preconcentrate the analyte prior its derivatization and subsequent detection by fluorescence. In this work, a novel method for the determination of dissolved zinc (Zn) at subnanomolar levels in seawater is described. The proposed method combines, for the first time, automated matrix removal, extraction of the target element, and fluorescence detection within a miniaturized flow manifold, based on the Lab-On-Valve (LOV) concept. The key feature of the microfluidic manipulation of the sample is flow programming, designed to pass sample through a mini-column where the target analyte and other complexable cations are retained, while the seawater matrix is washed out. Next, zinc is eluted and merged with a Zn selective fluorescent probe (FluoZin-3) at the confluence point of the LOV central channel using two high-precision stepper motor driven pumps that are operated in concert. Finally, the thus formed Zn complex is transported to the LOV flow cell for selective fluorescence measurement. This work describes the characterization and optimization of the method including Solid Phase Extraction using the Toyopearl AF-Chelate-650M resin, and detailed assay protocol controlled by a commercially available software and instrument. The proposed method features a LOD of 0.02 nM, high precision (<3% at 0.1 and 2 nM Zn levels), an assay cycle of 13 min and a reagent consumption of 150 μL FluoZin-3 per sample, which makes the method highly suitable for oceanographic shipboard analysis. The accuracy of the method has been validated through the analysis of seawater reference standards and comparison with ICP-MS determinations on

  7. Evaluation of a novel PTFE material for use as a means for separation and preconcentration of trace levels of metal ions in sequential injection (SI) and sequential injection lab-on-valve (SI-LOV) systems. Determination of cadmium (II) with detection by electrothermal atomic absorption spectrometry

    DEFF Research Database (Denmark)

    Long, Xiangbao; Chomchoei, Roongrat; Hansen, Elo Harald;

    2004-01-01

    an external packed column and in a sequential injection lab-on-valve (SI-LOV) system. Employed for the determination of cadmium(II), complexed with diethyldithiophosphate (DDPA), and detection by electrothermal atomic absorption spectrometry (ETAAS), its performance was compared to that of a...

  8. Multi-walled carbon nanotubes and metal-organic framework nanocomposites as novel hybrid electrode materials for the determination of nano-molar levels of lead in a lab-on-valve format.

    Science.gov (United States)

    Wang, Yang; Wu, Yichun; Xie, Jing; Ge, Huali; Hu, Xiaoya

    2013-09-01

    Metal-organic frameworks have been the subject of intense research because of their unique physicochemical properties. The presented study investigates the application of multi-wall carbon nanotubes and metal-organic frameworks (MWCNTs@Cu3(BTC)2) nanoparticles-modified electrode for the determination of trace levels of lead. The nanocomposites were prepared by solvothermal synthesis and characterized in detail. The experimental procedure was carried out by accumulating lead on the electrode surface and subsequently measuring with differential pulse anodic stripping voltammetry in a lab-on-valve format. The main parameters affecting the analytical performance, including the amount of MWCNTs@Cu3(BTC)2 suspension, supporting electrolyte and its pH, stripping mode, and flow rate, have been investigated in detail. Under the optimum conditions, the oxidation peak current displayed a calibration response for lead over a concentration range from 1.0 × 10(-9) to 5.0 × 10(-8) mol L(-1) with a excellent detection limit of 7.9 × 10(-10) mol L(-1). The relative standard deviation of 7 successive scans was 3.10% for 1.0 × 10(-8) mol L(-1) lead. The established method showed a great improvement in sensitivity and sample throughput for lead analysis. PMID:23853779

  9. Large volume preconcentration and determination of nanomolar concentrations of iron in seawater using a renewable cellulose 8-hydroquinoline sorbent microcolumn and universal approach of post-column eluate utilization in a Lab-on-Valve system.

    Science.gov (United States)

    Horstkotte, Burkhard; Chocholouš, Petr; Solich, Petr

    2016-04-01

    We report on a Lab-On-Valve (LOV) configuration for analyte preconcentration from milliliter sample volumes using confluent mixing in the holding coil for in-line addition of loading buffer. The system was applied to the spectrophotometric determination of iron(II) in acidified seawater using 1,10-phenanthroline as color reagent. A cellulose-based chelating sorbent containing 8-hydroxyquinoline was used for the first time in LOV and excellent retention behavior and loading capacity were found. The flow system employs a syringe pump for handling all solutions (sorbent suspension, loading buffer, water, eluent, and color reagent) and a peristaltic pump for sample propulsion and includes a fit-for-purpose 14cm long detection glass flow cell and a bubble trap for in-line carrier degasification. Advantage was taken of the LOV flow-through port to keep the eluted analytes for re-aspiration for subsequent chromogenic reaction. In effect, a universal analyzer configuration and preconcentration procedure was developed, which is combinable with other analytes, sorbents, and reagents. Among the studied parameters were the compositions, pH, volumes, and flow rates of loading buffer, eluent, and color reagent, as well as the microcolumn size, repeatability, and system stability. Reproducibility of 4.1% RSD over the entire working range, a LOD of down to 5nmolL(-1), sampling frequency of 12h(-1), and linearity up to 1µmolL(-1) for 3.3mL of sample were obtained and applicability to real samples was demonstrated. It was proven that both Fe(III) and Fe(II) were retained and yielded similar recovery and sensitivity values. The method was applied to coastal seawater samples and spiking experiments yielded recovery values close to 100%. PMID:26838402

  10. Towards chemiluminescence detection in micro-sequential injection lab-on-valve format: a proof of concept based on the reaction between Fe(II) and luminol in seawater.

    Science.gov (United States)

    Oliveira, Hugo M; Grand, Maxime M; Ruzicka, Jaromir; Measures, Christopher I

    2015-02-01

    Micro-sequential injection lab-on-valve (µSI-LOV) is a well-established analytical platform for absorbance and fluorescence based assays but its applicability to chemiluminescence detection remains largely unexplored. In this work, we describe a novel fluidic protocol and two distinct strategies for photon collection that enable chemiluminescence detection using µSI-LOV for the first time. To illustrate this proof of concept, we selected the reaction between Fe(II) and luminol and developed a preliminary protocol for Fe(II) determinations in acidified seawater. The optimized fluidic strategy consists of holding 100 µL of the luminol reagent in a confined zone of the LOV and then displacing it with 50 µL of sample while monitoring the chemiluminescent product. Detection is achieved using two strategies: one based on a bifurcated optical fiber and the other based on a customized detection window created by mounting a photomultiplier tube atop of the LOV device. We show that detection is possible using both strategies but that the window strategy yields significantly enhanced sensitivity (355×) due to the larger detection area. In our final experimental conditions and using window detection, it was possible to achieve a limit of detection (LOD) of 1 nmol L(-1) and to quantify Fe(II) in acidified seawater samples up to 20.00 nmol L(-1) with high precision (RSDanalysis of Fe(II). The intrinsic capacity of the LOV to operate at a low microliter level and to handle solid phases also opens up a new avenue for chemiluminescence applications. Moreover, this contribution shows that LOV can be a universal platform for optical detection, capable of absorbance, fluorescence and luminescence measurements in a single instrument setup. PMID:25435235

  11. HYPHENATED TECHNIQUE- A BOON TO ANALYTICAL WORLD

    Directory of Open Access Journals (Sweden)

    Rachana R. Joshi* Krishna R. Gupta and Shitalkumar S. Patil

    2012-11-01

    Full Text Available Traditional analytical approaches including HPLC (High-Performance Liquid Chromatograph, GC (Gas Chromatograph, UV (Ultraviolet detection, etc., have become insufficient to effectively handle the growing number of challenges in analyses of species- specificity and sensitivity. Modern analytical technique referred to as hyphenated techniques, originate from the traditional use of molecule or element specific detection in electrophoresis or chromatography. Currently the most common techniques for trace element speciation include a combination of separation technique coupled with a detection technique that is more sensitive. Earlier such hyphenated techniques were the coupling of separation of a special sample preparation off-line and later adding a detection technique. Presently, the hyphenated technique is developed from the coupling of a separation technique (Chromatography and an on-line spectroscopic detection technology. Hyphenated techniques combine chromatographic and spectral methods to exploit the advantages of both. Chromatography produces pure or nearly pure fractions of chemical components in a mixture. Spectroscopy produces selective information for identification using standards or library spectra. These hyphenated techniques offer shorter analysis time, higher degree of automation, higher sample throughput, better reproducibility, reduction of contamination because it is a closed system, Enhanced combined selectivity and therefore higher degree of information. The remarkable improvements in hyphenated analytical methods over the last two decades have significantly broadened their applications in the analysis of biomaterials, especially natural products. In this article, recent advances in the applications of various hyphenated techniques, e.g., GC-MS, LC-MS, LC-FTIR, LC-NMR, CE-MS, etc. in the context of pre-isolation analyses of crude extracts or fraction from various natural sources, isolation and on-line detection of natural

  12. HYPHENATED TECHNIQUE- A BOON TO ANALYTICAL WORLD

    OpenAIRE

    Rachana R. Joshi* Krishna R. Gupta and Shitalkumar S. Patil

    2012-01-01

    Traditional analytical approaches including HPLC (High-Performance Liquid Chromatograph), GC (Gas Chromatograph), UV (Ultraviolet) detection, etc., have become insufficient to effectively handle the growing number of challenges in analyses of species- specificity and sensitivity. Modern analytical technique referred to as hyphenated techniques, originate from the traditional use of molecule or element specific detection in electrophoresis or chromatography. Currently the most common technique...

  13. Immanuel and Me With-Out Hyphen

    OpenAIRE

    Andre Gunder Frank

    2015-01-01

    This essay is my personal and intellectual tribute to Immanuel Wallerstein. It takes the form of my also personal intellectual account of our ?rst independent, then joint, and again increasingly separate journeys through the maze of the world [-] system with and without a hyphen. Imagine our relations as a horizontal Y shaped rope. It began with strands that, in the 1960s, ran parallel, becoming intertwined during the 1970s and 1980s until the strands (or at least some) separated again in the...

  14. Hyphenated spectroscopy as a polymorph screening tool.

    Science.gov (United States)

    Aaltonen, Jaakko; Strachan, Clare J; Pöllänen, Kati; Yliruusi, Jouko; Rantanen, Jukka

    2007-06-28

    Polymorph screening of a model compound (nitrofurantoin) was performed. Nitrofurantoin was crystallized from acetone-water mixtures with varying process parameters. Two anhydrate forms (alpha and beta) and one monohydrate form (II) were crystallized in the polymorph screen. The solid forms were analyzed with three complementary spectroscopic techniques: near-infrared (NIR) spectroscopy, Raman spectroscopy and terahertz pulsed spectroscopy (TPS), and the results of the solid phase analysis were verified with X-ray powder diffraction (XRPD). NIR and Raman spectroscopy were coupled to achieve a rapid and comprehensive method of solid phase analysis. The hyphenated NIR/Raman spectroscopic data were analyzed with a multivariate method, principal component analysis (PCA). The combination was found effective in screening solid forms due to the complementary characteristics of the methods. NIR spectroscopy is powerful in differentiating between anhydrate and hydrate forms and intermolecular features, whereas Raman spectroscopy is sensitive to intramolecular alterations in the molecular backbone. PMID:17367979

  15. Hyphenated techniques and their applications in natural products analysis.

    Science.gov (United States)

    Sarker, Satyajit D; Nahar, Lutfun

    2012-01-01

    A technique where a separation technique is coupled with an online spectroscopic detection technology is known as hyphenated technique, e.g., GC-MS, LC-PDA, LC-MS, LC-FTIR, LC-NMR, LC-NMR-MS, and CE-MS. Recent advances in hyphenated analytical techniques have remarkably widened their applications to the analysis of complex biomaterials, especially natural products. This chapter focuses on the applications of hyphenated techniques to pre-isolation and isolation of natural products, dereplication, online partial identification of compounds, chemotaxonomic studies, chemical finger-printing, quality control of herbal products, and metabolomic studies, and presents specific examples. However, a particular emphasis has been given on the hyphenated techniques that involve an LC as the separation tool. PMID:22367902

  16. Immanuel and Me With-Out Hyphen

    Directory of Open Access Journals (Sweden)

    Andre Gunder Frank

    2015-08-01

    Full Text Available This essay is my personal and intellectual tribute to Immanuel Wallerstein. It takes the form of my also personal intellectual account of our ?rst independent, then joint, and again increasingly separate journeys through the maze of the world [-] system with and without a hyphen. Imagine our relations as a horizontal Y shaped rope. It began with strands that, in the 1960s, ran parallel, becoming intertwined during the 1970s and 1980s until the strands (or at least some separated again in the 1990s, going off in increasingly different directions like a horizontal Y. Why? My answer is both circumstantial and personal, in which the personal choices and trajectories are driven primarily by world and local political circumstance. Of course, my account re?ects my own perspective on this story. However it also includes other colleagues and friends of Immanuel’s and mine, in particular our co-authors in several books and edited volumes, Giovanni Arrighi and Samir Amin, with whom I can check this account. Others, alas, are no longer with us.

  17. Direct 13C NMR Detection in HPLC Hyphenation Mode

    DEFF Research Database (Denmark)

    Wubshet, Sileshi Gizachew; Johansen, Kenneth; Nyberg, Nils;

    2012-01-01

    is indubitable in simplifying structural elucidations. In the current study, we demonstrated direct (13)C NMR detection of triterpenoids from a Ganoderma lucidum extract in hyphenation mode. The combined advantage of a cryogenically cooled probe, miniaturization, and multiple trapping enabled the...

  18. Mass spectrometry and hyphenated instruments in food analysis

    Science.gov (United States)

    Mass spectrometry (MS) has come a long way since the record of the first mass spectra of a simple low molecular weight substance by J.J. Thomson in 1912. Especially over the past decades, MS has been the subject of many developments. Particularly, the hyphenation of MS to gas chromatography (GC) a...

  19. The Hyphen as a Syllabification Cue in Reading Bisyllabic and Multisyllabic Words among Finnish 1st and 2nd Graders

    Science.gov (United States)

    Häikiö, Tuomo; Bertram, Raymond; Hyönä, Jukka

    2016-01-01

    Finnish ABC books present words with hyphens inserted at syllable boundaries. Syllabification by hyphens is abandoned in the 2nd grade for bisyllabic words, but continues for words with three or more syllables. The current eye movement study investigated how and to what extent syllable hyphens in bisyllabic ("kah-vi" "cof-fee")…

  20. Hyphenation of Field-Flow Fractionation and Magnetic Particle Spectroscopy

    Directory of Open Access Journals (Sweden)

    Norbert Löwa

    2015-11-01

    Full Text Available Magnetic nanoparticles (MNPs exhibit unique magnetic properties making them ideally suited for a variety of biomedical applications. Depending on the desired magnetic effect, MNPs must meet special magnetic requirements which are mainly determined by their structural properties (e.g., size distribution. The hyphenation of chromatographic separation techniques with complementary detectors is capable of providing multidimensional information of submicron particles. Although various methods have already been combined for this approach, so far, no detector for the online magnetic analysis was used. Magnetic particle spectroscopy (MPS has been proven a straightforward technique for specific quantification and characterization of MNPs. It combines high sensitivity with high temporal resolution; both of these are prerequisites for a successful hyphenation with chromatographic separation. We demonstrate the capability of MPS to specifically detect and characterize MNPs under usually applied asymmetric flow field-flow fractionation (A4F conditions (flow rates, MNP concentration, different MNP types. To this end MPS has been successfully integrated into an A4F multidetector platform including dynamic ligth scattering (DLS, multi-angle light scattering (MALS and ultraviolet (UV detection. Our system allows for rapid and comprehensive characterization of typical MNP samples for the systematic investigation of structure-dependent magnetic properties. This has been demonstrated by magnetic analysis of the commercial magnetic resonance imaging (MRI contrast agent Ferucarbotran (FER during hydrodynamic A4F fractionation.

  1. Polymer architectures via mass spectrometry and hyphenated techniques: A review.

    Science.gov (United States)

    Crotty, Sarah; Gerişlioğlu, Selim; Endres, Kevin J; Wesdemiotis, Chrys; Schubert, Ulrich S

    2016-08-17

    This review covers the application of mass spectrometry (MS) and its hyphenated techniques to synthetic polymers of varying architectural complexities. The synthetic polymers are discussed as according to their architectural complexity from linear homopolymers and copolymers to stars, dendrimers, cyclic copolymers and other polymers. MS and tandem MS (MS/MS) has been extensively used for the analysis of synthetic polymers. However, the increase in structural or architectural complexity can result in analytical challenges that MS or MS/MS cannot overcome alone. Hyphenation to MS with different chromatographic techniques (2D × LC, SEC, HPLC etc.), utilization of other ionization methods (APCI, DESI etc.) and various mass analyzers (FT-ICR, quadrupole, time-of-flight, ion trap etc.) are applied to overcome these challenges and achieve more detailed structural characterizations of complex polymeric systems. In addition, computational methods (software: MassChrom2D, COCONUT, 2D maps etc.) have also reached polymer science to facilitate and accelerate data interpretation. Developments in technology and the comprehension of different polymer classes with diverse architectures have significantly improved, which allow for smart polymer designs to be examined and advanced. We present specific examples covering diverse analytical aspects as well as forthcoming prospects in polymer science. PMID:27286765

  2. Microemulsion electrokinetic chromatography hyphenated to atmospheric pressure photoionization mass spectrometry.

    Science.gov (United States)

    Schappler, Julie; Guillarme, Davy; Rudaz, Serge; Veuthey, Jean-Luc

    2008-01-01

    CZE is an appropriate technique for separating charged species, but lacks selectivity for neutral compounds. Alternative approaches such as microemulsion electrokinetic chromatography (MEEKC) have been developed to broaden its range of applications. Hyphenation of MEEKC with MS is an attractive perspective since it can enhance sensitivity and selectivity. The on-line coupling of MEEKC with MS, however, is not straightforward due to the low compatibility of non-volatile surfactant additives (e.g. SDS) and the commonly used API source, namely ESI. In order to hyphenate MEEKC with MS detection, the atmospheric pressure photoionization (APPI) source was investigated. Possibilities offered by the coupling of MEEKC with APPI-MS were highlighted for the complex separation of ionized and neutral compounds in both the positive and negative modes. MEEKC-APPI-MS performance, in terms of selectivity, efficiency and sensitivity was compared to CZE-ESI-MS and MEEKC-ESI-MS for the screening of doping substances (beta-blockers, central stimulants, diuretics, etc). Relevant selectivity and detectability, particularly for neutral, structurally related and isobaric compounds was demonstrated with the MEEKC-APPI-MS approach opening new avenues for CE-MS, in addition to the well-established CZE-ESI-MS technique. PMID:18161697

  3. Advantages and disadvantages of nuclear magnetic resonance spectroscopy as a hyphenated technique

    Energy Technology Data Exchange (ETDEWEB)

    Silva Elipe, Maria Victoria

    2003-11-14

    A general overview of the advancements and applications of nuclear magnetic resonance (NMR) hyphenated with other analytical techniques is given from a practical point of view. Details on the advantages and disadvantages of the hyphenation of NMR with liquid chromatography as LC-NMR and also with mass spectrometry as LC-MS-NMR are demonstrated with two examples. Current developments of NMR with other analytical separation techniques, especially with capillary liquid chromatography (capLC) are discussed.

  4. Comparison of gas chromatographic hyphenated techniques for mercury speciation analysis.

    Science.gov (United States)

    Nevado, J J Berzas; Martín-Doimeadios, R C Rodríguez; Krupp, E M; Bernardo, F J Guzmán; Fariñas, N Rodríguez; Moreno, M Jiménez; Wallace, D; Ropero, M J Patiño

    2011-07-15

    In this study, we evaluate advantages and disadvantages of three hyphenated techniques for mercury speciation analysis in different sample matrices using gas chromatography (GC) with mass spectrometry (GC-MS), inductively coupled plasma mass spectrometry (GC-ICP-MS) and pyrolysis atomic fluorescence (GC-pyro-AFS) detection. Aqueous ethylation with NaBEt(4) was required in all cases. All systems were validated with respect to precision, with repeatability and reproducibility TMAH). No statistically significant differences were found to the certified values (p=0.05). The suitability for water samples analysis with different organic matter and chloride contents was evaluated by recovery experiments in synthetic spiked waters. Absolute detection and quantification limits were in the range of 2-6 pg for GC-pyro-AFS, 1-4 pg for GC-MS, with 0.05-0.21 pg for GC-ICP-MS showing the best limits of detection for the three systems employed. However, all systems are sufficiently sensitive for mercury speciation in environmental samples, with GC-MS and GC-ICP-MS offering isotope analysis capabilities for the use of species-specific isotope dilution analysis, and GC-pyro-AFS being the most cost effective alternative. PMID:21641604

  5. Editor's intervention in the register of compounds in archaic Portuguese texts: some reflections on the use of hyphen

    Directory of Open Access Journals (Sweden)

    Antonia Vieira dos Santos

    2014-07-01

    Full Text Available The use of hyphen within compounds was not built up before the nineteenth century. Thus, compounds spelled with hyphen in archaic Portuguese texts are a result of editing criteria adopted by editors. From this type of intervention, the relationship between hyphen use – result of a spelling convention – and the definition of compound adopted by the editor are discussed. Its absence is significant to the history of the language.

  6. The Three Generations of Flow Injection Analysis

    DEFF Research Database (Denmark)

    Hansen, Elo Harald; Wang, Jianhua

    2004-01-01

    The characteristics of the three generations of flow injection analysis, that is, FIA, sequential injection analysis (SIA), and bead injection-lab-on-valve (BI-LOV), are briefly outlined, their individual advantages and shortcomings are discussed, and selected practical applications are presented....

  7. New Trends in Flow Injection Analysis: Exploitation of Sequential and Lab-on-Valve Schemes

    DEFF Research Database (Denmark)

    Hansen, Elo Harald

    by electrothermal atomic absorption spectrometry (ETAAS) and inductively coupled plasma mass spectrometry (ICPMS). Despite their excellent analytical chemical capabilities, these detection devices, nevertheless, often require that the samples are subjected to suitable pretreatment in order to obtain...

  8. Electrophoretic separation techniques and their hyphenation to mass spectrometry in biological inorganic chemistry.

    Science.gov (United States)

    Holtkamp, Hannah; Grabmann, Gerlinde; Hartinger, Christian G

    2016-04-01

    Electrophoretic methods have been widely applied in research on the roles of metal complexes in biological systems. In particular, CE, often hyphenated to a sensitive MS detector, has provided valuable information on the modes of action of metal-based pharmaceuticals, and more recently new methods have been added to the electrophoretic toolbox. The range of applications continues to expand as a result of enhanced CE-to-MS interfacing, with sensitivity often at picomolar level, and evolved separation modes allowing for innovative sample analysis. This article is a followup to previous reviews about CE methods in metallodrug research (Electrophoresis, 2003, 24, 2023-2037; Electrophoresis, 2007, 28, 3436-3446; Electrophoresis, 2012, 33, 622-634), also providing a comprehensive overview of metal species studied by electrophoretic methods hyphenated to MS. It highlights the latest CE developments, takes a sneak peek into gel electrophoresis, traces biomolecule labeling, and focuses on the importance of early-stage drug development. PMID:26643265

  9. Determination of iodide in samples with complex matrices by hyphenation of capillary isotachophoresis and zone electrophoresis

    Czech Academy of Sciences Publication Activity Database

    Pantůčková, Pavla; Urbánek, Marek; Křivánková, Ludmila

    Olomouc: Palacký University, 2007 - (Petr, J.; Znaleziona, J.; Ranc, V.; Vítková, K.). s. 134 ISBN 978-80-244-1705-9. [Advances in Chromatography and Electrophoresis 2007 & CHIRANAL 2007. 24.06.2007-27.06.2007, Olomouc] R&D Projects: GA ČR GA203/05/2106; GA AV ČR IAA400310703 Institutional research plan: CEZ:AV0Z40310501 Keywords : hyphenation of capillary isotachophoresis and zone electrophoresis * iodide Subject RIV: CB - Analytical Chemistry, Separation

  10. Contribution of chromatography and hyphenated technology to production process development for pharma chemicals

    International Nuclear Information System (INIS)

    'Chromatography' is an indispensable technique for treating small organic molecules, and 'Hyphenated Technology', which means a combination of two different techniques (in this case, chromatography and mass spectrometry, etc.), is a powerful tool for quick on-line identification of trace amount impurities in processes. During production process development for active pharmaceutical ingredients (APIs) and reactive intermediates, these techniques are mainly utilized for confirmation of synthesized target molecules, by-products and impurities, and also for their identification. This paper describes the contribution of these techniques to process study acceleration and product quality improvement, while showing some examples. (author)

  11. speciation of selenium in human biological samples using online hyphenation of HPLC and ICP-MS

    International Nuclear Information System (INIS)

    Selenium is an important trace element that plays specific biological role in organism. Since bioactivity of selenium is a consequence of individual chemical species, there is considerable interest in the speciation of selenium in the mammalian organism. Inasmuch as selenium is primarily present in the form of selenoproteins in mammalian tissues, speciation studies of Se-containing proteins are focused on the various organs and tissues. Serum and urine samples can be used for study of Se metabolites in vivo. Hyphenation of chromatographic separation with element-specific detection has been proved as a powerful technique for Se speciation analysis recently. In present study, using an ion-pair reversed-phase liquid chromatography, Se species such as selenite (Se(IV>), selenate (Se(VI>), trimethyl selenonium (TMSe+), selenocystine (SeCys), selenourea (SeUr), selenomethionine (SeMet), and selenocystamine (SeCM) are separated and followed by the online coupling detection as introduced below. A 5-μm Symmetry Shield RP18 column was applied for the analysis of Se compounds using 0.1% HFBA in 1:99 methanol-water buffer as mobile phase. Elemental signal detected by ICP-MS geminated in case of collision cell technique (CCT) mode, since the most abundant isotope 80Se instead of 82Se or 78Se monitored in ordinary model. More sensitive technique based on ICP-MS and CCT can recognize signals of Se standard compounds, whose concentrations were less than l ppb in hyphenation experiment, and Se concentrations of quantitative analysis could reach several ppb. Human liver cytoplasm and serum samples gave legible chromatograms with a few peaks recognized easily, while urine samples of human gave much more complex chromatograms according to the intricate components. The uncertainty of measurement will be estimated too.Nevertheless, both of serum and urine samples give quantifiable elemental signals, while cytoplasm samples gave weaker signals referring to the lower concentrations of Se

  12. HPTLC Hyphenated with FTIR: Principles, Instrumentation and Qualitative Analysis and Quantitation

    Science.gov (United States)

    Cimpoiu, Claudia

    In recent years, much effort has been devoted to the coupling of high-performance thin-layer chromatography (HPTLC) with spectrometric methods because of the robustness and simplicity of HPTLC and the need for detection techniques that provide identification and determination of sample constituents. IR is one of the spectroscopic methods that have been coupled with HPTLC. IR spectroscopy has a high potential for the elucidation of molecular structures, and the characteristic absorption bands can be used for compound-specific detection. HPTLC-FTIR coupled method has been widely used in the modern laboratories for the qualitative and quantitative analysis. The potential of this method is demonstrated by its application in different fields of analysis such as drug analysis, forensic analysis, food analysis, environmental analysis, biological analysis, etc. The hyphenated HPTLC-FTIR technique will be developed in the future with the aim of taking full advantage of this method.

  13. Speaking the Unspeakable - The Hyphenated in the Irish-Caribbean Dialogue

    Directory of Open Access Journals (Sweden)

    Mahmoud Gewaily

    2014-12-01

    Full Text Available Speaking the unspeakable is to see how far the creative acts of cultural translation in the conflict between history and memory sharpen a natural native knack to converge in a polyphonic way. I pay special attention to the influence that the archetypal theme of speaking the unspeakable in the novel through the initiation experience of the subaltern develops and exerts in the context of increased intercultural awareness. This awareness of the cultural dilemma seems especially important because, in my observation, there is as much alienation and chaos among individuals in the daily contexts of speech communication as among heroes in the imagined communities of literary texts. The hyphenated Irish-Caribbean dialogue of this article aims to bridge cultures in the literary thought of the many writers. Padraic O Conaire and George Lamming, in the two works of Exile (E and The Pleasures of Exile (PE, respectively, are given as examples of the dialogic interlocution.

  14. Real-time 2D separation by LC × differential ion mobility hyphenated to mass spectrometry.

    Science.gov (United States)

    Varesio, Emmanuel; Le Blanc, J C Yves; Hopfgartner, Gérard

    2012-03-01

    The liquid chromatography-mass spectrometry (LC-MS) analysis of complex samples such as biological fluid extracts is widespread when searching for new biomarkers as in metabolomics. The success of this hyphenation resides in the orthogonality of both separation techniques. However, there are frequent cases where compounds are co-eluting and the resolving power of mass spectrometry (MS) is not sufficient (e.g., isobaric compounds and interfering isotopic clusters). Different strategies are discussed to solve these cases and a mixture of eight compounds (i.e., bromazepam, chlorprothixene, clonapzepam, fendiline, flusilazol, oxfendazole, oxycodone, and pamaquine) with identical nominal mass (i.e., m/z 316) is taken to illustrate them. Among the different approaches, high-resolution mass spectrometry or liquid chromatography (i.e., UHPLC) can easily separate these compounds. Another technique, mostly used with low resolving power MS analyzers, is differential ion mobility spectrometry (DMS), where analytes are gas-phase separated according to their size-to-charge ratio. Detailed investigations of the addition of different polar modifiers (i.e., methanol, ethanol, and isopropanol) into the transport gas (nitrogen) to enhance the peak capacity of the technique were carried out. Finally, a complex urine sample fortified with 36 compounds of various chemical properties was analyzed by real-time 2D separation LC×DMS-MS(/MS). The addition of this orthogonal gas-phase separation technique in the LC-MS(/MS) hyphenation greatly improved data quality by resolving composite MS/MS spectra, which is mandatory in metabolomics when performing database generation and search. PMID:22006241

  15. Analytical approaches to the study of hyaluronan and hyaluronidases: Development and application of hyphenated chromatographic and electrophoretic methods

    OpenAIRE

    Rothenhöfer, Martin

    2014-01-01

    Hyaluronan (HA) and HA oligosaccharides, which are produced when HA is enzymatically degraded by hyaluronidases, are supposed to have various size-dependent biological effects. To study the (patho)physiological role of HA oligosaccharides, appropriate (bio)analytical methods are a prerequisite. Hence, hyphenated chromatographic and electrophoretic techniques were developed and optimized. Capillary zone electrophoresis coupled to time-of-flight mass spectrometry (CZE–ESI-TOF-MS) is suited ...

  16. SFC-APLI-(TOF)MS: Hyphenation of Supercritical Fluid Chromatography to Atmospheric Pressure Laser Ionization Mass Spectrometry.

    Science.gov (United States)

    Klink, Dennis; Schmitz, Oliver Johannes

    2016-01-01

    Atmospheric-pressure laser ionization mass spectrometry (APLI-MS) is a powerful method for the analysis of polycyclic aromatic hydrocarbon (PAH) molecules, which are ionized in a selective and highly sensitive way via resonance-enhanced multiphoton ionization. APLI was presented in 2005 and has been hyphenated successfully to chromatographic separation techniques like high performance liquid chromatography (HPLC) and gas chromatography (GC). In order to expand the portfolio of chromatographic couplings to APLI, a new hyphenation setup of APLI and supercritical-fluid chromatography (SFC) was constructed and aim of this work. Here, we demonstrate the first hyphenation of SFC and APLI in a simple designed way with respect to different optimization steps to ensure a sensitive analysis. The new setup permits qualitative and quantitative determination of native and also more polar PAH molecules. As a result of the altered ambient characteristics within the source enclosure, the quantification of 1-hydroxypyrene (1-HP) in human urine is possible without prior derivatization. The limit of detection for 1-HP by SFC-APLI-TOF(MS) was found to be 0.5 μg L(-1), which is lower than the 1-HP concentrations found in exposed persons. PMID:26633261

  17. Chromatographic analysis of Polygalae Radix by online hyphenating pressurized liquid extraction

    Science.gov (United States)

    Song, Yuelin; Song, Qingqing; Li, Jun; Shi, Shepo; Guo, Liping; Zhao, Yunfang; Jiang, Yong; Tu, Pengfei

    2016-06-01

    Practicing “green analytical chemistry” is of great importance when profiling the chemical composition of complex matrices. Herein, a novel hybrid analytical platform was developed for direct chemical analysis of complex matrices by online hyphenating pressurized warm water extraction followed by turbulent flow chromatography coupled with high performance liquid chromatography-tandem mass spectrometry (PWWE-TFC-LC-MS/MS). Two parallel hollow guard columns acted as extraction vessels connected to a long narrow polyether ether ketone tube, while warm water served as extraction solvent and was delivered at a flow rate of 2.5 mL/min to generate considerable back pressure at either vessel. A column oven heated both the solvent and crude materials. A TFC column, which is advantageous for the comprehensive trapping of small molecular substances from fluids under turbulent flow conditions, was employed to transfer analytes from the PWWE module to LC-MS/MS. Two electronic valves alternated each vessel between extraction and elution phases. As a proof-of-concept, a famous herbal medicine for the treatment of neurodegenerative disorders, namely Polygalae Radix, was selected for the qualitative and quantitative analyses. The results suggest that the hybrid platform is advantageous in terms of decreasing time, material, and solvent consumption and in its automation, versatility, and environmental friendliness.

  18. Hyphenated GC-FTIR and GC-MS techniques applied in the analysis of bioactive compounds

    Science.gov (United States)

    Gosav, Steluta; Paduraru, Nicoleta; Praisler, Mirela

    2014-08-01

    The drugs of abuse, which affect human nature and cause numerous crimes, have become a serious problem throughout the world. There are hundreds of amphetamine analogues on the black market. They consist of various alterations of the basic amphetamine molecular structure, which are yet not yet included in the lists of forbidden compounds although they retain or slightly modify the hallucinogenic effects of their parent compound. It is their important variety that makes their identification quite a challenge. A number of analytical procedures for the identification of amphetamines and their analogues have recently been reported. We are presenting the profile of the main hallucinogenic amphetamines obtained with the hyphenated techniques that are recommended for the identification of illicit amphetamines, i. e. gas chromatography combined with mass spectrometry (GC-MS) and gas chromatography coupled with Fourier transform infrared spectrometry (GC-FTIR). The infrared spectra of the analyzed hallucinogenic amphetamines present some absorption bands (1490 cm-1, 1440 cm-1, 1245 cm-1, 1050 cm-1 and 940 cm-1) that are very stable as position and shape, while their intensity depends of the side-chain substitution. The specific ionic fragment of the studied hallucinogenic compounds is the 3,4-methylenedioxybenzyl cation (m/e = 135) which has a small relative abundance (lesser than 20%). The complementarity of the above mentioned techniques for the identification of hallucinogenic compounds is discussed.

  19. Screening of cadmium and lead in potentially contaminated waters using a spectrophotometric sequential injection lab-on-valve methodology.

    Science.gov (United States)

    Santos, Inês C; Mesquita, Raquel B R; Rangel, António O S S

    2015-10-01

    The present work describes the development of a µSI-LOV method for the simultaneous screening of cadmium and lead in potentially contaminated water samples. To attain the biparametric determination, dithizone was chosen as the spectrophotometric reagent as it forms a colored complex with both metal ions, at different pH conditions. The cadmium determination was attained in strong alkaline conditions (pH≈12); the lead determination was calculated by the difference with the determination of both metals in mild alkaline conditions (pH≈8). The colored complex was measured at 550 nm and the method presented a LOD of 34 μg L(-1) for cadmium and 56 μg L(-1) for lead, with a sample consumption of 20 µL per assay and a determination rate of 55 h(-1). The results obtained were in agreement with those obtained by FAAS. The developed method was efficiently applied to the screening of cadmium and lead in marine port waters. PMID:26078171

  20. Chemometric profile of root extracts of Rhodiola imbricata Edgew. with hyphenated gas chromatography mass spectrometric technique.

    Directory of Open Access Journals (Sweden)

    Amol B Tayade

    Full Text Available Rhodiola imbricata Edgew. (Rose root or Arctic root or Golden root or Shrolo, belonging to the family Crassulaceae, is an important food crop and medicinal plant in the Indian trans-Himalayan cold desert. Chemometric profile of the n-hexane, chloroform, dichloroethane, ethyl acetate, methanol, and 60% ethanol root extracts of R. imbricata were performed by hyphenated gas chromatography mass spectrometry (GC/MS technique. GC/MS analysis was carried out using Thermo Finnigan PolarisQ Ion Trap GC/MS MS system comprising of an AS2000 liquid autosampler. Interpretation on mass spectrum of GC/MS was done using the NIST/EPA/NIH Mass Spectral Database, with NIST MS search program v.2.0g. Chemometric profile of root extracts revealed the presence of 63 phyto-chemotypes, among them, 1-pentacosanol; stigmast-5-en-3-ol, (3β,24S; 1-teracosanol; 1-henteracontanol; 17-pentatriacontene; 13-tetradecen-1-ol acetate; methyl tri-butyl ammonium chloride; bis(2-ethylhexyl phthalate; 7,8-dimethylbenzocyclooctene; ethyl linoleate; 3-methoxy-5-methylphenol; hexadecanoic acid; camphor; 1,3-dimethoxybenzene; thujone; 1,3-benzenediol, 5-pentadecyl; benzenemethanol, 3-hydroxy, 5-methoxy; cholest-4-ene-3,6-dione; dodecanoic acid, 3-hydroxy; octadecane, 1-chloro; ethanone, 1-(4-hydroxyphenyl; α-tocopherol; ascaridole; campesterol; 1-dotriacontane; heptadecane, 9-hexyl were found to be present in major amount. Eventually, in the present study we have found phytosterols, terpenoids, fatty acids, fatty acid esters, alkyl halides, phenols, alcohols, ethers, alkanes, and alkenes as the major group of phyto-chemotypes in the different root extracts of R. imbricata. All these compounds identified by GC/MS analysis were further investigated for their biological activities and it was found that they possess a diverse range of positive pharmacological actions. In future, isolation of individual phyto-chemotypes and subjecting them to biological activity will definitely prove fruitful

  1. Effect-directed analysis of fresh and dried elderberry (Sambucus nigra L.) via hyphenated planar chromatography.

    Science.gov (United States)

    Krüger, S; Mirgos, M; Morlock, G E

    2015-12-24

    A healthy diet is an important factor in a healthy lifestyle that is becoming increasingly important in today's society. The fruits of European elder (Sambucus nigra L.) are a rich source of bioactive compounds like anthocyanins. In this study, dried and fresh fruits of four cultivated and six wild growing plants were investigated for their anthocyanin pattern and content as well as their bioactive compounds. After separation on HPTLC plates silica gel 60 F254 with a mixture of ethyl acetate, 2-butanone, formic acid and water, the plates were quantitatively evaluated by densitometry and also subjected to various (bio)assays to investigate the samples for compounds acting as radical-scavengers, antimicrobials, estrogens, and acetylcholinesterase or tyrosinase inhibitors. The mean contents for the two most abundant anthocyanins in European elderberries, confirmed by HPTLC-ESI-MS, ranged from 159 to 647mg/100g in fresh and from 166 to 2764mg/100g in dried fruits for cyanidin-3-sambubioside, and from 112 to 521mg/100g in fresh and 95 to 226mg/100g in dried fruits for cyanidin-3-glucoside. Additionally, the anthocyanin content was higher in berries of cultivars than of wild growing plants. The anthocyanins' radical scavenging activity and antimicrobial effect against Aliivibrio fischeri were confirmed. Further, a radical scavenging compound affecting A. fischeri and acting as acetylcholinesterase inhibitor was tentatively assigned by its protonated molecule at m/z 456 as either ursolic or oleanolic acid by HPTLC-ESI-MS. HPTLC hyphenated with bioassays and mass spectrometry was selected as method of choice for fingerprinting, pattern recognition, and bioprofiling of elderberry samples as well as quantitation and confirmation of bioactive compounds therein. PMID:26643726

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

    OpenAIRE

    Ming-Chi Wei; Yu-Chiao Yang; Show-Jen Hong

    2015-01-01

    Oleanolic acid (OA) and ursolic acid (UA) were extracted from Hedyotis diffusa using a hyphenated procedure of ultrasound-assisted and supercritical carbon dioxide (HSC–CO2) extraction at different temperatures, pressures, cosolvent percentages, and SC–CO2 flow rates. The results indicated that these parameters significantly affected the extraction yield. The maximal yields of OA (0.917 mg/g of dry plant) and UA (3.540 mg/g of dry plant) were obtained at a dynamic extraction time of 110 min, ...

  3. Instrumentation of High Temperature and Pressure Reaction System with Continuous Flow and Its Hyphenation to a Liquid Chromatograph

    OpenAIRE

    Tsuda, Takao; Kitagawa, Shinya; Umeyama, Takayuki; Araki, Shuki; Hirashita, Tsunehisa; Aoki, Mutsumi; Nakamura, Koichi; キタガワ, シンヤ; アラキ, シュウキ; ヒラシタ, ツネヒサ; アオキ, ムツミ; 北川, 慎也; 荒木, 修喜; 平下, 恒久; 青木, 睦

    2006-01-01

    A continuous flow-type hydrothermal reaction system, in which both temperature and pressure were rapidly and dynamically controlled, was constructed. It is called a real time high temperature and pressure reaction system (RT-HighTP). The RT-HighTP was hyphenated with liquid chromatograph (RT-HighTP-LC) to achieve prompt analysis of the reaction products. The RT-HighTP system produced stable pressure under the supercritical and subcritical phases (%RSD < 3%). The RT-HighTP-LC was able to chang...

  4. Chromatography and its hyphenation to mass spectrometry for extracellular vesicle analysis.

    Science.gov (United States)

    Pocsfalvi, Gabriella; Stanly, Christopher; Fiume, Immacolata; Vékey, Károly

    2016-03-25

    and phosphorylation are becoming feasible and increasingly important. Along with conventional LC-MS/MS, other chromatographic approaches hyphenated to MS are gaining importance for EV characterization. Hydrophilic interaction LC is used to characterize PTMs; LC-inductively coupled plasma/MS to identify metal containing molecules; while gas chromatography-MS to analyze some lipids and metabolites. PMID:26830636

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

    Directory of Open Access Journals (Sweden)

    Ming-Chi Wei

    2015-01-01

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

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

    Science.gov (United States)

    Wei, Ming-Chi; Yang, Yu-Chiao; Hong, Show-Jen

    2015-01-01

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

  7. Hyphenation of infrared spectroscopy to liquid chromatography for qualitative and quantitative polymer analysis: Degradation of poly(bisphenol A)carbonate

    NARCIS (Netherlands)

    Coulier, L.; Kaal, E.; Hankemeier, T.

    2006-01-01

    Hyphenation of infrared spectroscopy (IR) to liquid chromatography (LC) has been applied to study chemical changes in poly(bisphenol A)carbonate (PC) as a result of degradation. Especially coupling of LC to FTIR through solvent elimination is a sensitive approach to identify changes in functionality

  8. Hyphenation of gas-diffusion separation and ion chromatography. Part 1: determination of free sulfite in wines.

    Science.gov (United States)

    Fäldt, S; Karlberg, B; Frenzel, W

    2001-10-01

    The hyphenation of gas-diffusion separation and ion chromatography (IC) is described as a convenient, reliable, robust, and economic method for in-line sample pre-treatment. The high selectivity associated with this method permits direct analysis of samples containing microparticulates, colloidal matter, and/or high molecular weight compounds. The determination of sulfite serves as a first example of its application. The method is based on the diffusional separation of SO2 following in-line oxidation with hydrogen peroxide to sulfate and final determination of the sulfate formed using IC. The influence of operational parameters has been thoroughly investigated and gas-diffusion cells of different geometries compared with respect to the gas-transfer rates obtained. Application to the analysis of wines demonstrates the utility of the method. PMID:11760049

  9. Electrospray-Differential Mobility Hyphenated with Single Particle Inductively Coupled Plasma Mass Spectrometry for Characterization of Nanoparticles and Their Aggregates.

    Science.gov (United States)

    Tan, Jiaojie; Liu, Jingyu; Li, Mingdong; El Hadri, Hind; Hackley, Vincent A; Zachariah, Michael R

    2016-09-01

    The novel hyphenation of electrospray-differential mobility analysis with single particle inductively coupled plasma mass spectrometry (ES-DMA-spICPMS) was demonstrated with the capacity for real-time size, mass, and concentration measurement of nanoparticles (NPs) on a particle-to-particle basis. In this proof-of-concept study, the feasibility of this technique was validated through both concentration and mass calibration using NIST gold NP reference materials. A detection limit of 10(5) NPs mL(-1) was determined under current experimental conditions, which is about 4 orders of magnitude lower in comparison to that of a traditional ES-DMA setup using a condensation particle counter as detector. Furthermore, independent and simultaneous quantification of both size and mass of NPs provides information regarding NP aggregation states. Two demonstrative applications include gold NP mixtures with a broad size range (30-100 nm), and aggregated gold NPs with a primary size of 40 nm. Finally, this technique was shown to be potentially useful for real-world samples with high ionic background due to its ability to remove dissolved ions yielding a cleaner background. Overall, we demonstrate the capacity of this new hyphenated technique for (1) clearly resolving NP populations from a mixture containing a broad size range; (2) accurately measuring a linear relationship, which should inherently exist between mobility size and one-third power of ICPMS mass for spherical NPs; (3) quantifying the early stage propagation of NP aggregation with well-characterized oligomers; and (4) differentiating aggregated NPs and nonaggregated states based on the "apparent density" derived from both DMA size and spICPMS mass. PMID:27479448

  10. Hyphenation of two simultaneously employed soft photo ionization mass spectrometers with thermal analysis of biomass and biochar

    International Nuclear Information System (INIS)

    Highlights: ► First simultaneous hyphenation of two time-of-flight mass spectrometers with different soft photo ionization techniques (SPI and REMPI) to Thermal Analysis using a newly developed prototype for EGA is presented. ► Resonance enhanced multi-photon ionization (REMPI) enables sensitive and selective analysis of aromatic species. ► Single photon ionization (SPI) using VUV light supplied by an innovative electron-beam pumped excimer light source (EBEL) comprehensively ionizes (nearly) all organic molecules. ► The resulting mass spectra show distinct patterns for the evolved gases of the miscellaneous biomasses and chars thereof. ► The potential for detailed kinetic studies is apparent on account of the complex pyrolysis gas compositions. - Abstract: Evolved gas analysis (EGA) is a powerful and complementary tool for Thermal Analysis. In this context, two time-of-flight mass spectrometers with different soft photo-ionization techniques are simultaneously hyphenated to a thermo balance and applied in form of a newly developed prototype for EGA of pyrolysis gases from biomass and biochar. Resonance enhanced multi-photon ionization (REMPI) is applied for selective analysis of aromatic species. Furthermore, single photon ionization (SPI) using VUV light supplied by an electron-beam pumped excimer light source (EBEL) was used to comprehensively ionize (nearly) all organic molecules. The soft ionization capability of photo-ionization techniques allows direct and on-line analysis of the evolved pyrolysis gases. Characteristic mass spectra with specific patterns could be obtained for the miscellaneous biomass feeds used. Temperature profiles of the biochars reveal a desorption step, followed by pyrolysis as observed for the biomasses. Furthermore, the potential for kinetic studies is apparent for this instrumental setup.

  11. Algorithm for comprehensive analysis of datasets from hyphenated high resolution mass spectrometric techniques using single ion profiles and cluster analysis.

    Science.gov (United States)

    Erny, Guillaume L; Acunha, Tanize; Simó, Carolina; Cifuentes, Alejandro; Alves, Arminda

    2016-01-15

    Various algorithms have been developed to improve the quantity and quality of information that can be extracted from complex datasets obtained using hyphenated mass spectrometric techniques. While different approaches are possible, the key step often consists in arranging the data into a large series of profiles known as extracted ion profiles. Those profiles, similar to mono-dimensional separation profiles, are then processed to detect potential chromatographic peaks. This allows extracting from the dataset a large number of peaks that are characteristics of the compounds that have been separated. However, with mass spectrometry (MS) detection, the response is usually a complex signal whose pattern depends on the analyte, the MS instrument and the ionization method. When converted to ionic profiles, a single separated analyte will have multiple images at different m/z range. In this manuscript we present a hierarchical agglomerative clustering algorithm to group profiles with very similar feature. Each group aims to contain all profiles that are due to the transport and monitoring of a single analyte. Clustering results are then used to generate a 2 dimensional representation, called clusters plot, which allows an in-depth analysis of the MS dataset including the visualization of poorly separated compounds even when their intensity differs by more than two orders of magnitude. The usefulness of this new approach has been validated with data from capillary electrophoresis time of flight mass spectrometry hyphenated via an electrospray ionization. Using a mixture of 17 low molecular endogenous compounds it was verified that ionic profiles belonging to each compounds were correctly clustered even with very low degree of separation (R below 0.03). The approach was also validated using a urine sample. While with the total ion profile 15 peaks could be distinguished, 70 clusters were obtained allowing a much thorough analysis. In this particular example, the total

  12. Development of bio-analytical methods for the quantitative and qualitative analysis of labelled peptides and proteins via hyphenation of chromatography and mass spectrometry

    OpenAIRE

    Holste, Angela Sarah

    2014-01-01

    This PhD thesis was a Cotutelle between the Université de Pau et des Pays de l’Adour (UPPA) in Pau, France and the Christian-Albrechts University (CAU) in Kiel, Germany. In the course of this international collaboration, bio-analytical methods for the quantitative and qualitative analysis of labelled peptides and proteins were developed, which were based on the hyphenation of chromatography with mass spectrometry. Peptides and protein digests were lanthanide labelled using DOTA-based comp...

  13. Development of a microfluidic confocal fluorescence detection system for the hyphenation of nano-LC to on-line biochemical assays

    OpenAIRE

    Heus, F.; Giera, M.A.; Kloe, de, G.E.; Iperen, van, C.; Buijs, J.B.; Nahar, T.T.; Smit, A B; Lingeman, H.; Esch, van, Joep; Niessen, W.M.A.; Irth, H.; Kool, J.

    2010-01-01

    One way to profile complex mixtures for receptor affinity is to couple liquid chromatography (LC) on-line to biochemical detection (BCD). A drawback of this hyphenated screening approach is the relatively high consumption of sample, receptor protein and (fluorescently labeled) tracer ligand. Here, we worked toward minimization of sample and reagent consumption, by coupling nano-LC on-line to a light-emitting diode (LED) based capillary confocal fluorescence detection system capable of on-line...

  14. Surface enhanced Raman spectroscopy hyphenated with surface microextraction for in-situ detection of polycyclic aromatic hydrocarbons on food contact materials.

    Science.gov (United States)

    Zhang, Min; Zhang, Xiaoli; Shi, Yu-E; Liu, Zhen; Zhan, Jinhua

    2016-09-01

    Highly bioaccumulated polycyclic aromatic hydrocarbons (PAHs) have cause health concerns because of their carcinogenic properties. PAHs could migrate to food from contaminated food contact materials. In this study, a hyphenated technique combining surface enhanced Raman spectroscopy (SERS) with surface microextraction was developed for in-situ on site screening of PAHs on food contact materials. Methanol and 1-propanethiol-modified silver nanoparticles (PTH-Ag NPs) were used to perform the in-situ microextraction and detection of PAHs, respectively. The SERS spectra can be obtained by a portable Raman spectrometer. The vibration of the C-C bond of PTH at 1030cm(-1) was chosen as an internal standard peak. The PTH-Ag NPs showed high uniformity with an RSD of 2.96%. A plot of the normalized SERS intensity against fluoranthene concentration showed a linear relationship (R(2)=0.98). The detection limit could reach 0.27ngcm(-2). The in-situ microextraction-SERS hyphenated technique for the detection of three PAHs at five food contact materials was demonstrated. The method can be also applied to detect PAH mixtures. This in-situ microextraction-SERS hyphenated method demonstrated its ability to rapidly screen PAHs on contaminated food contact materials free from complex sample pretreatment. PMID:27343612

  15. Different Ways to On-Line Hyphenate Centrifugal Partition Chromatography and Mass Spectrometry: Application to Prenylated Xanthones from Garcinia mangostana.

    Science.gov (United States)

    Destandau, Emilie; Michel, Thomas; Toribio, Alix; Elfakir, Claire

    2015-11-01

    Centrifugal partition chromatography is a liquid-liquid separation method well adapted for the fractionation or purification of natural compounds from plant extracts. However, following the preparative isolation, the fractions collected must be analysed by high-performance thin-layer chromatography or high-performance liquid chromatography to evaluate their composition and/or their purity. These additional steps are time-consuming and increase the risk of compound degradation. In order to get an instantaneous analysis of fraction content with structural information on the phytochemicals eluted, it is possible to hyphenate on-line centrifugal partition chromatography with mass spectrometry. Depending on the complexity of the extract, two different kinds of centrifugal partition chromatography-mass spectrometry coupling can be performed: centrifugal partition chromatography-mass spectrometry or centrifugal partition chromatography-high-performance liquid chromatography-mass spectrometry coupling. In the first case, one part of the centrifugal partition chromatography effluent is directly introduced in the mass spectrometry ionisation source to identify the eluted compounds, while in the second case, it is directed to a high-performance liquid chromatography-mass spectrometry system where compounds are first separated thanks to high-performance liquid chromatography and then identified using mass spectrometry. PMID:25615274

  16. High performance liquid chromatography hyphenated to inductively coupled plasma mass spectrometry for V and Ni quantification as tetrapyrroles

    Science.gov (United States)

    Duyck, Christiane Béatrice; Saint'Pierre, Tatiana Dillenburg; Miekeley, Norbert; da Fonseca, Teresa Cristina Oliveira; Szatmari, Peter

    2011-05-01

    A method was developed for the determination of V and Ni as tetrapyrroles by High Performance Liquid Chromatography hyphenated to Inductively Coupled Plasma Mass Spectrometry (HPLC-ICP-MS) using reversed phase and elution gradient. Chlorinated solvents and tetrahydrofuran were investigated as regard to separation time and ICP-MS detection efficiencies. The final elution gradient program started from pure methanol to a mixture of 20:80 (v/v) chloroform:methanol. External quantification of V and Ni with inorganic standards by flow injection ICP-MS, used online with HPLC, resulted in 95% of recoveries. The Limits of Detection for V during methanol elution and for Ni during the 20% chloroform gradient elution were evaluated by their minimum detectable concentrations, which were, respectively, 5 μg L - 1 and 8 μg L - 1 . The methodology was applied to polar and resin fractions separated from a Brazilian crude oil and a sediment extract from an oil-polluted area in the Guanabara Bay, Rio de Janeiro, Brazil. Vanadium as tetrapyrroles represented the totality of V content in the polar fraction, whereas Ni was in different polar forms in the resin and sediment extract.

  17. High performance liquid chromatography hyphenated to inductively coupled plasma mass spectrometry for V and Ni quantification as tetrapyrroles

    International Nuclear Information System (INIS)

    A method was developed for the determination of V and Ni as tetrapyrroles by High Performance Liquid Chromatography hyphenated to Inductively Coupled Plasma Mass Spectrometry (HPLC-ICP-MS) using reversed phase and elution gradient. Chlorinated solvents and tetrahydrofuran were investigated as regard to separation time and ICP-MS detection efficiencies. The final elution gradient program started from pure methanol to a mixture of 20:80 (v/v) chloroform:methanol. External quantification of V and Ni with inorganic standards by flow injection ICP-MS, used online with HPLC, resulted in 95% of recoveries. The Limits of Detection for V during methanol elution and for Ni during the 20% chloroform gradient elution were evaluated by their minimum detectable concentrations, which were, respectively, 5 μg L-1 and 8 μg L-1. The methodology was applied to polar and resin fractions separated from a Brazilian crude oil and a sediment extract from an oil-polluted area in the Guanabara Bay, Rio de Janeiro, Brazil. Vanadium as tetrapyrroles represented the totality of V content in the polar fraction, whereas Ni was in different polar forms in the resin and sediment extract.

  18. High performance liquid chromatography hyphenated to inductively coupled plasma mass spectrometry for V and Ni quantification as tetrapyrroles

    Energy Technology Data Exchange (ETDEWEB)

    Duyck, Christiane Beatrice, E-mail: cbduyck@vm.uff.br [Pontificia Universidade Catolica do Rio de Janeiro (PUC-Rio), R. Marques de Sao Vicente, 225, Gavea, Rio de Janeiro, RJ, 22451-900 (Brazil); Universidade Federal Fluminense (UFF), Campus do Valonguinho, Outeiro de Sao Joao Batista, s/no, 24020-150, Niteroi, RJ (Brazil); Saint' Pierre, Tatiana Dillenburg; Miekeley, Norbert [Pontificia Universidade Catolica do Rio de Janeiro (PUC-Rio), R. Marques de Sao Vicente, 225, Gavea, Rio de Janeiro, RJ, 22451-900 (Brazil); Oliveira da Fonseca, Teresa Cristina; Szatmari, Peter [Centro de Pesquisas Leopoldo A. Miguez de Mello da Petrobras (CENPES), Av. Horacio Macedo, 950, Cidade Universitaria, Rio de Janeiro, RJ, 21941-915 (Brazil)

    2011-05-15

    A method was developed for the determination of V and Ni as tetrapyrroles by High Performance Liquid Chromatography hyphenated to Inductively Coupled Plasma Mass Spectrometry (HPLC-ICP-MS) using reversed phase and elution gradient. Chlorinated solvents and tetrahydrofuran were investigated as regard to separation time and ICP-MS detection efficiencies. The final elution gradient program started from pure methanol to a mixture of 20:80 (v/v) chloroform:methanol. External quantification of V and Ni with inorganic standards by flow injection ICP-MS, used online with HPLC, resulted in 95% of recoveries. The Limits of Detection for V during methanol elution and for Ni during the 20% chloroform gradient elution were evaluated by their minimum detectable concentrations, which were, respectively, 5 {mu}g L{sup -1} and 8 {mu}g L{sup -1}. The methodology was applied to polar and resin fractions separated from a Brazilian crude oil and a sediment extract from an oil-polluted area in the Guanabara Bay, Rio de Janeiro, Brazil. Vanadium as tetrapyrroles represented the totality of V content in the polar fraction, whereas Ni was in different polar forms in the resin and sediment extract.

  19. Multidimensional gas chromatography hyphenated to mass spectrometry and olfactometry for the volatile analysis of citrus hybrid peel extract.

    Science.gov (United States)

    Casilli, Alessandro; Decorzant, Erik; Jaquier, Alain; Delort, Estelle

    2014-12-19

    In this work, the volatile composition of the peel extract of limequat, a natural citrus hybrid, was investigated by using both conventional (gas chromatography-mass spectrometry [GC-MS], deconvolution) and more advanced (multidimensional GC-MS/olfactometry [MDGC-MS/O] and enantioselective [Es]-MDGC-MS/O) analytical techniques. Although the GC-MS analysis identified most of the components, some peaks remained unidentified. These unknown peaks were elucidated by deconvolution processing and using a selectable one-dimensional or two-dimensional GC-MS system equipped with an olfactometry port. The MDGC results, with both polar and chiral second dimensions, hyphenated to mass spectrometry and olfactometry, proved to be particularly useful for the identification and chiral characterization of coeluted trace compounds. In particular, the application of the Es-MDGC-MS/O configurations was used to confirm, by on-line enrichment, the presence of cis-δ-jasminlactone. This technique was fundamental for the reliable identification and exact determination of the enantiomeric distribution of this chiral compound, as well as for the sensorial evaluation of each enantiomer at the sniffing port. PMID:25482037

  20. A Hyphenated Technique based on High-Performance Thin Layer Chromatography for Determining Neutral Sphingolipids: A Proof of Concept

    Directory of Open Access Journals (Sweden)

    Andrés Domínguez

    2015-04-01

    Full Text Available Hyphenated HPTLC has been used to analyze several neutral sphingolipids acting as lysosomal storage disease (LSD biomarkers. Automated multiple development (AMD provides separation of lipid peaks, which are detected and quantified using fluorescence detection by intensity changes (FDIC after primuline post-impregnation. A final online transfer to a mass spectrometer by means of an elution-based interface allows their identification using electrospray ionization (ESI and atmospheric pressure chemical ionization (APCI.Given that the increases in fluorescent emission detected by FDIC are produced by non-specific, electrostatic interactions between the primuline and hydrocarbon chains in the ceramide backbones of sphingolipids, it is a non-destructive detection technique, allowing the precise location and transfer of biomarker peaks to a mass spectrometer using an elution interface. By using primuline as a fluorophore, the technique is also compatible with ESI-APCI and does not interfere with the MS of sphingolipids. APCI provides useful and complementary structural information to the ESI for sphingolipid identification. Moreover, FDIC emission can be used for quantitative purposes. Results include the determination of sphingomyelin (SM in human-plasma samples (RSD < 6% by means of a standard addition method with non-linear calibration, and the identification of globotriaosylceramide (Gb3 in the plasma of a Fabry patient. Only one HPTLC plate is needed to perform the analysis.

  1. The impact of flow injection on modem chemical analysis: has it fulfilled our expectations? And where are we going?

    DEFF Research Database (Denmark)

    Hansen, Elo Harald

    2004-01-01

    Presenting a condensation of the opening lecture of the 12th ICFIA conference, this communication presents a view of the impact that flow injection analysis (FIA) has had on modern analytical chemistry, evaluated both within the academic community and outside it, i.e., in “industry”. The ensuing ...... developments of FIA, encompassing sequential injection analysis (SIA) and bead injection lab-on-valve (BI-LOV), are described and their individual features discussed. Finally some recent results of the activities from the author’s own research group are briefly mentioned....

  2. Aging of Cations of Ionic Liquids Monitored by Ion Chromatography hyphenated to an Electrospray Ionization Mass Spectrometer

    International Nuclear Information System (INIS)

    Highlights: • Proposed decomposition mechanisms for the cations. • No influence of the electrolyte salts on the decomposition behavior of the IL cation was observed. • A new method for the identification of decomposition products in ILs. - ABSTRACT: The stability of 1-methyl-1-propylpyrrolidinium bis(trifluoromethanesulfonyl) imide (PYR13TFSI), 1-methyl-1-propylpyrrolidinium bis(fluorosulfonyl) imide (PYR13FSI), 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl) imide (PYR14TFSI) and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl) imide (EMIM TFSI) ionic liquids (ILs) at different temperatures (room temperature and 95 °C) was investigated by ion chromatography (IC) hyphenated to a mass spectrometer. The degradation of the cations can be summarized in the following way: The side chain of the main molecule cleaves and reacts subsequently with the main cation molecule to new decomposition products. In addition, the results show that at elevated temperatures more decomposition products are formed. The influence of Li+ cation based electrolyte salts, lithium hexafluorophosphate (LiPF6), lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) and lithium perchlorate (LiClO4), on the decomposition of the ionic liquids was analyzed over a long term stability study at room temperature and 60 °C. It was found out that in the mixtures of ILs and electrolyte salt, the same decomposition products were formed like in the pure ILs at the same temperature. Accordingly, there is no influence of the electrolyte salts on the decomposition behavior of the IL cation. The influence of the counter anion on the decomposition of PYR13+ was analyzed as well. It was observed that different decomposition products were detected for PYR13TFSI and PYR13FSI

  3. Hyphenated and comprehensive liquid chromatography × gas chromatography-mass spectrometry for the identification of Mycobacterium tuberculosis.

    Science.gov (United States)

    Mourão, Marta P B; Denekamp, Ilse; Kuijper, Sjoukje; Kolk, Arend H J; Janssen, Hans-Gerd

    2016-03-25

    Tuberculosis is one of the world's most emerging public health problems, particularly in developing countries. Chromatography based methods have been used to tackle this epidemic by focusing on biomarker detection. Unfortunately, interferences from lipids in the sputum matrix, particularly cholesterol, adversely affect the identification and detection of the marker compounds. The present contribution describes the serial combination of normal phase liquid chromatography (NPLC) with thermally assisted hydrolysis and methylation followed by gas chromatography-mass spectrometry (THM-GC-MS) to overcome the difficulties of biomarker evaluation. The in-series combination consists of an LC analysis where fractions are collected and then transferred to the THM-GC-MS system. This was either done with comprehensive coupling, transferring all the fractions, or with hyphenated interfacing, i.e. off-line multi heart-cutting, transferring only selected fractions. Owing to the high sensitivity and selectivity of LC as a sample pre-treatment method, and to the high specificity of the MS as a detector, this analytical approach, NPLC × THM-GC-MS, is extremely sensitive. The results obtained indicate that this analytical set-up is able to detect down to 1 × 10(3) mycobacteria/mL of Mycobacterium tuberculosis strain 124, spiked in blank sputum samples. It is a powerful analytical tool and also has great potential for full automation. If further studies demonstrate its usefulness when applied blind in real sputum specimens, this technique could compete with the current smear microscopy in the early diagnosis of tuberculosis. PMID:26585206

  4. Characterization of the Axial Jet Separator with a CO2/Helium Mixture: Toward GC-AMS Hyphenation.

    Science.gov (United States)

    Salazar, G; Agrios, K; Eichler, R; Szidat, S

    2016-02-01

    Development of interfaces for sample introduction from high pressures is important for real-time online hyphenation of chromatographic and other separation devices with mass spectrometry (MS) or accelerator mass spectrometry (AMS). Momentum separators can reduce unwanted low-density gases and introduce the analyte into the vacuum. In this work, the axial jet separator, a new momentum interface, is characterized by theory and empirical optimization. The mathematical model describes the different axial penetration of the components of a jet-gas mixture and explains the empirical results for injections of CO2 in helium into MS and AMS instruments. We show that the performance of the new interface is sensitive to the nozzle size, showing good qualitative agreement with the mathematical model. Smaller nozzle sizes are more preferable due to their higher inflow capacity. The CO2 transmission efficiency of the interface into a MS instrument is ∼ 14% (CO2/helium separation factor of 2.7). The interface receives and delivers flows of ∼ 17.5 mL/min and ∼ 0.9 mL/min, respectively. For the interfaced AMS instrument, the ionization and overall efficiencies are 0.7-3% and 0.1-0.4%, respectively, for CO2 amounts of 4-0.6 μg C, which is only slightly lower compared to conventional systems using intermediate trapping. The ionization efficiency depends on to the carbon mass flow in the injected pulse and is suppressed at high CO2 flows. Relative to a conventional jet separator, the transmission efficiency of the axial jet separator is lower, but its performance is less sensitive to misalignments. PMID:26652049

  5. Sensitive redox speciation of iron, neptunium, and plutonium by capillary electrophoresis hyphenated to inductively coupled plasma sector field mass spectrometry.

    Science.gov (United States)

    Graser, Carl-Heinrich; Banik, Nidhu Lal; Bender, Kerstin Anne; Lagos, Markus; Marquardt, Christian Michael; Marsac, Rémi; Montoya, Vanessa; Geckeis, Horst

    2015-10-01

    The long-term safety assessment for nuclear waste repositories requires a detailed understanding of actinide (geo)chemistry. Advanced analytical tools are required to gain insight into actinide speciation in a given system. The geochemical conditions in the vicinity of a nuclear repository control the redox state of radionuclides, which in turn has a strong impact on their mobility. Besides the long-lived radionuclides plutonium (Pu) and neptunium (Np), which are key elements in high level nuclear waste, iron (Fe) represents a main component in natural systems controlling redox-related geochemical processes. Measuring the oxidation state distribution for redox sensitive radionuclides and other metal ions is challenging at trace concentrations below the detection limit of most available spectroscopic methods (≥10(-6) M). Consequently, ultrasensitive new analytical techniques are required. Capillary electrophoresis (CE) is a suitable separation method for metal cations. CE hyphenated to inductively coupled plasma sector field mass spectrometry (CE-ICP-SF-MS) was used to measure the redox speciation of Pu (III, IV, V, VI), Np (IV, V, VI), and Fe (II, III) at concentrations lower than 10(-7) M. CE coupling and separation parameters such as sample gas pressure, make up flow rate, capillary position, auxiliary gas flow, as well as the electrolyte system were optimized to obtain the maximum sensitivity. We obtain detection limits of 10(-12) M for Np and Pu. The various oxidation state species of Pu and Np in different samples were separated by application of an acetate-based electrolyte system. The separation of Fe (II) and Fe (III) was investigated using different organic complexing ligands, EDTA, and o-phenanthroline. For the Fe redox system, a limit of detection of 10(-8) M was calculated. By applying this analytical system to sorption studies, we were able to underline previously published results for the sorption behavior of Np in highly diluted concentrations, and

  6. Study of the interactions between the transuranic elements and some environmental ligands by the hyphenated technique capillary electrophoresis: inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    In this work, the capabilities of the hyphenated Capillary Electrophoresis-ICP-MS technique are used to improve the knowledge on the transuranic element speciation in the environment (nuclear waste management) and in the framework of spent fuel reprocessing. Essential thermodynamical data have been determined for the first time for the interactions of the plutonium at the (5+) oxidation state (main soluble species of Pu of the surface water) in inorganic media (chloride, nitrate, sulfate, carbonate). This study enables to correct the existing model, based on the thermodynamical data of the neptunium at the (5+) oxidation state (analogue of the pentavalent plutonium). Furthermore, the hyphenated CE-ICP-MS technique has also been applied to study the interactions between DTPA, widely used in the nuclear industry, and the elements at the (3+) oxidation state (Pu, Am, Cm, Cf) and at the (4+) oxidation state (Pu, Np, Th). The results show for the first time the formation of mixed An(IV)/DTPA/OH complexes likely to play a key role on the actinide behavior in the field of the waste management. The study on the trivalent elements confirms the selectivity of DTPA versus the actinide in the framework of the actinide/lanthanide separation but proves that the covalency, responsible of the selectivity, are less important than the ionicity in the binding. (author)

  7. Micro solid phase spectrophotometry in a sequential injection lab-on-valve platform for cadmium, zinc, and copper determination in freshwaters.

    Science.gov (United States)

    Santos, Inês C; Mesquita, Raquel B R; Rangel, António O S S

    2015-09-01

    This work describes the development of a solid phase spectrophotometry method in a μSI-LOV system for cadmium, zinc, and copper determination in freshwaters. NTA (Nitrilotriacetic acid) beads with 60-160 μm diameter were packed in the flow cell of the LOV for a μSPE column of 1 cm length. The spectrophotometric determination is based on the colourimetric reaction between dithizone and the target metals, previously retained on NTA resin. The absorbance of the coloured product formed is measured, at 550 nm, on the surface of the NTA resin beads in a solid phase spectrophotometry approach. The developed method presented preconcentration factors in the range of 11-21 for the metal ions. A LOD of 0.23 μg L(-1) for cadmium, 2.39 μg L(-1) for zinc, and 0.11 μg L(-1) for copper and a sampling rate of 12, 13, and 15 h(-1) for cadmium, zinc, and copper were obtained, respectively. The proposed method was successfully applied to freshwater samples. PMID:26388376

  8. Lab-on-Valve Micro Sequential Injection: A Versatile Approach for Implementing Integrated Sample Pre-preparations and Executing (Bio)Chemical Assays

    DEFF Research Database (Denmark)

    Hansen, Elo Harald

    of applications. Particular focus will be placed on its use as a vehicle for pretreatment of complex sample matrices for determination of trace-level concentrations of metal ions by electrothermal atomic absorption spectrometry (ETAAS) and inductively coupled plasma mass spectrometry (ICPMS) via exploitation...... interfering matrix constituents, or to preconcentrate the analyte material to bring it into the dynamic range of the detector. As will be shown, such pretreatments are advantageously performed in FIA/SIA/LOV manifolds, where all appropriate unit operations can be effected under enclosed and strictly...

  9. Lab-on-Valve Micro Sequential Injection: A Versatile Approach for Implementing Integrated Sample Pre-preparations and Executing (Bio)Chemical Assays

    DEFF Research Database (Denmark)

    Hansen, Elo Harald

    will be directed towards its use as a vehicle for on-line pretreatment of complex sample matrices for determination of trace-level concentrations of metal ions by electrothermal atomic absorption spectrometry (ETAAS) and inductively coupled plasma mass spectrometry (ICPMS) via exploitation of the renewable solid...... and selectivity. Either in order to separate the analyte from potentially interfering matrix constituents, or to preconcentrate the analyte material to bring it into the dynamic range of the detector. As will be shown, such pretreatments are advantageously performed in FIA/SIA/LOV manifolds, where all appropriate...

  10. Recent developments in automated determinations of trace level concentrations of elements and on-line fractionations schemes exploiting the micro-sequential injection - lab-on-valve approach

    DEFF Research Database (Denmark)

    Hansen, Elo Harald; Miró, Manuel; Long, Xiangbao;

    2006-01-01

    The determination of trace level concentrations of elements, such as metal species, in complex matrices by atomic absorption or emission spectrometric methods often require appropriate pretreatments comprising separation of the analyte from interfering constituents and analyte preconcentration...

  11. Inline roasting hyphenated with gas chromatography-mass spectrometry as an innovative approach for assessment of cocoa fermentation quality and aroma formation potential.

    Science.gov (United States)

    Van Durme, Jim; Ingels, Isabel; De Winne, Ann

    2016-08-15

    Today, the cocoa industry is in great need of faster and robust analytical techniques to objectively assess incoming cocoa quality. In this work, inline roasting hyphenated with a cooled injection system coupled to a gas chromatograph-mass spectrometer (ILR-CIS-GC-MS) has been explored for the first time to assess fermentation quality and/or overall aroma formation potential of cocoa. This innovative approach resulted in the in-situ formation of relevant cocoa aroma compounds. After comparison with data obtained by headspace solid phase micro extraction (HS-SPME-GC-MS) on conventional roasted cocoa beans, ILR-CIS-GC-MS data on unroasted cocoa beans showed similar formation trends of important cocoa aroma markers as a function of fermentation quality. The latter approach only requires small aliquots of unroasted cocoa beans, can be automatated, requires no sample preparation, needs relatively short analytical times (<1h) and is highly reproducible. PMID:27006215

  12. Analysis of the volatile oil from the stem of acanthopanax senticosus(Rupr.et Maxim.)harms with several hyphenated methods of chromatography

    Institute of Scientific and Technical Information of China (English)

    Yu Wanying; Zhang Hua; Huang Weidong; Chen Jiping; Liang Xinmiao

    2006-01-01

    Gas chromatography/quadrupole mass spectrometry (GC/qMS),gas chromatography/Fourier transform infrared spectrometry(CC/FTIR)and gas chromatography/orthogonal acceleration time-of-flight mass spectrometry(GC/oaTOFMS)were applied to analyze the volatile oil from the stem of Acanthopanax Senticosus(Rupr.et Maxim.)Harms.Based on the mass spectra search function of GC/qMS with the aid of the discriminability of the geometrical isomer by GC/FTIR and the ability to determine the accurate mass charge ratio(m/z)by GC/oaTOFMS,68 GC eluants were identified successfully.Compared with the results obtained by GC/qMS only,the analytical results obtained by these hyphenated methods of gas chromatography are more credible.

  13. The use of LC/MS, GC/MS, and LC/NMR hyphenated techniques to identify a drug degradation product in pharmaceutical development.

    Science.gov (United States)

    Pan, Changkang; Liu, Frances; Ji, Qin; Wang, Wei; Drinkwater, Donald; Vivilecchia, Richard

    2006-02-24

    Understanding drug degradation in the formulated product is critical in pharmaceutical development as it has significant impacts on drug efficacy, safety profile and storage conditions. As a result, identification of degradation compounds has taken an important role in the drug development process. In this study, various hyphenated analytical techniques, such as liquid chromatography mass spectrometry (LC/MS), gas chromatography mass spectrometry (GC/MS), and liquid chromatography nuclear magnetic resonance with a solid phase extraction interface (LC/SPE/NMR), have been applied to the identification of a drug degradation product which grew over time in the stability study of the drug product. The target unknown is less polar and more unsaturated than the drug substance based upon reverse phase HPLC relative retention time and UV spectra. It is not ionizable by electrospray ionization (ESI) or atmospheric pressure chemical ionization (APCI) in either a positive or a negative mode. The unknown was isolated by an HPLC fraction collector and enriched by solid phase extraction. GC/MS with chemical ionization (CI) was employed to determine the molecular weight of this compound. Its fragmentation pattern was determined by CI-MS/MS using an ion trap mass spectrometer. The isolated material was also analyzed by LC/SPE/NMR, from which the structure of this compound was further characterized. The study utilizes a combination of various hyphenated analytical techniques to obtain complimentary information for structure elucidation of the unknown. The combination approach is critical for unambiguous impurity structure elucidation in drug degradation studies of pharmaceutical drug products. PMID:16242883

  14. Determination of sulfur and selected trace elements in metallothionein-like proteins using capillary electrophoresis hyphenated to inductively coupled plasma mass spectrometry with an octopole reaction cell

    International Nuclear Information System (INIS)

    The determination of sulfur in biologically relevant samples such as metalloproteins is described. The analytical methodology used is based on robust on-line coupling between capillary electrophoresis (CE) and octopole reaction cell inductively-coupled plasma mass spectrometry (ORC-ICP-MS). Polyatomic ions that form in the plasma and interfere with the determination of S at mass 32 are minimised by addition of xenon to the collision cell. The method has been applied to the separation and simultaneous element-specific detection of sulfur, cadmium, copper, and zinc in commercially available metallothionein preparations (MT) and metallothionein-like proteins (MLP) extracted from liver samples of bream (Abramis brama L.) caught in the river Elbe, Germany. Instrumental detection limits have been calculated according to the German standard procedure DIN 32645 for the determination of sulfur and some simultaneously measured trace elements in aqueous solution. For sulfur detection limits down to 1.3 μg L-1 (34S) and 3.2 μg L-1 (32S) were derived. For the other trace elements determined simultaneously detection limits ranging from 300 ng L-1 (58Ni) to 500 ng L-1 (66Zn, 55Mn) were achieved. For quantification of sulfur and cadmium in a commercially available MT preparation under hyphenated conditions the use of external calibration is suggested. Finally, the need for proper sample-preparation technique will be discussed. (orig.)

  15. Determination of sulfur and selected trace elements in metallothionein-like proteins using capillary electrophoresis hyphenated to inductively coupled plasma mass spectrometry with an octopole reaction cell

    Energy Technology Data Exchange (ETDEWEB)

    Proefrock, Daniel; Leonhard, Peter; Prange, Andreas [GKSS Research Centre Geesthacht, Institute for Coastal Research, Max Planck Strasse, 21502, Geesthacht (Germany)

    2003-09-01

    The determination of sulfur in biologically relevant samples such as metalloproteins is described. The analytical methodology used is based on robust on-line coupling between capillary electrophoresis (CE) and octopole reaction cell inductively-coupled plasma mass spectrometry (ORC-ICP-MS). Polyatomic ions that form in the plasma and interfere with the determination of S at mass 32 are minimised by addition of xenon to the collision cell. The method has been applied to the separation and simultaneous element-specific detection of sulfur, cadmium, copper, and zinc in commercially available metallothionein preparations (MT) and metallothionein-like proteins (MLP) extracted from liver samples of bream (Abramis brama L.) caught in the river Elbe, Germany. Instrumental detection limits have been calculated according to the German standard procedure DIN 32645 for the determination of sulfur and some simultaneously measured trace elements in aqueous solution. For sulfur detection limits down to 1.3 {mu}g L{sup -1} ({sup 34}S) and 3.2 {mu}g L{sup -1} ({sup 32}S) were derived. For the other trace elements determined simultaneously detection limits ranging from 300 ng L{sup -1} ({sup 58}Ni) to 500 ng L{sup -1} ({sup 66}Zn, {sup 55}Mn) were achieved. For quantification of sulfur and cadmium in a commercially available MT preparation under hyphenated conditions the use of external calibration is suggested. Finally, the need for proper sample-preparation technique will be discussed. (orig.)

  16. Research Progress in the Speciation of Arsenic with Hyphenated Techniques%联用技术在砷形态分析中的研究进展

    Institute of Scientific and Technical Information of China (English)

    李林林; 朱英存

    2013-01-01

    Currently the main analysis techniques for arsenic speciation were the combination of chromatograph with atomic spectrum and mass spectrum, especially the combination of HPLC with ICP-OES or ICP-MS. The methods were accurate and reliable and had high sensitivity. But they can not provide the structural information of arsenic compounds. So the combination of chromatograph with ESI-MS was used as the main method for qualitative analysis. The insufficient sensitivity and vulnerability to matrix interference of ESI-MS can be overcome by the complex pretreatment technique. In this article hyphenated techniques were evaluated with particular emphasis on interfaced separation with element-selective detection and identification of the arsenic compounds detected.%  目前用元素砷的形态分析技术主要是色谱与子光谱、质谱等的联用,最常用的是HPLC与ICP-OES、 ICP-MS的联用,方法准确可靠,灵敏度高,但是不能提供砷化合物的分子结构信息。此以色谱-电喷雾质谱(ESI-MS)的联用作为定性分析的主要手段,但是ESI-MS灵敏度低,易受基体干扰,此需要复杂的前处理技术。

  17. Mass spectrometry hyphenated techniques for the analysis of volatiles and peptides in soft cheese: Useful tools for the shelf life optimization.

    Science.gov (United States)

    Mentana, Annalisa; Natale, Anna; Palermo, Carmen; Nardiello, Donatella; Conte, Amalia; Del Nobile, Matteo Alessandro; Quinto, Maurizio; Centonze, Diego

    2016-07-01

    In order to assess the product quality and shelf life of an Italian soft cream cheese under different storage conditions, the volatile and peptide profiles evolution were tested. Volatiles were sampled directly from the head space of cheese packaging by solid-phase microextraction and analyzed by GC-MS. Peptide profiles were obtained by nanoLC-MS/MS, following a novel bioinformatics approach based on scoring distribution associated to the protein hits originating from the database search. In particular, a refined identification by focusing on selected time segments corresponding to the most intense peaks was carried out. A total of 40 compounds including acids, aldehydes, ketones, lactones, alcohols, esters, hydrocarbons, terpene, sulfur, and aromatic compounds were detected. Significant differences in their abundance during the storage in different packagings were observed, as well as an evolution of peptides mainly belonging to αS1-casein. The results demonstrated the usefulness of the above-mentioned hyphenated techniques for the determination of the soft cheese shelf life under different storage conditions. PMID:26800207

  18. Development of a novel low-flow ion source/sampling cone geometry for inductively coupled plasma mass spectrometry and application in hyphenated techniques

    International Nuclear Information System (INIS)

    A novel ion source/sampling cone device for inductively coupled plasma mass spectrometry (ICP-MS) especially operated in the hyphenated mode as a detection system coupled with different separation modules is presented. Its technical setup is described in detail. Its main feature is the very low total argon consumption of less than 1.5 L min−1, leading to significant reduction of operational costs especially when time-consuming speciation analysis is performed. The figures of merit of the new system with respect to sensitivity, detection power, long-term stability and working range were explored. Despite the profound differences of argon consumption of the new system in comparison to the conventional ICP-MS system, many of the characteristic features of the conventional ICP-MS could be maintained to a great extent. To demonstrate the ion source's capabilities, it was used as an element-selective detector for gas (GC) and high performance liquid chromatography (HPLC) where organic compounds of mercury and cobalt, respectively, were separated and detected with the new low-flow ICP-MS detection system. The corresponding chromatograms are shown. The applicability for trace element analysis has been validated with the certified reference material NIST 1643e. - Highlights: ► A low argon flow ion source and sampling interface for ICP-MS is presented. ► The approach saves more than 90% argon compared to conventional ICP-MS operation. ► Analytical performance is shown for sample introduction via solution nebulization. ► Low-flow ICP-MS was used as GC detector for the exemplary separation of Hg species. ► The system was also applied as LC detector to study cobalt-labeled ß-lactoglobulin.

  19. Speciation of the bio-available iodine and bromine forms in edible seaweed by high performance liquid chromatography hyphenated with inductively coupled plasma-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Romaris-Hortas, Vanessa; Bermejo-Barrera, Pilar [Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, Avenida das Ciencias, s/n. 15782 - Santiago de Compostela (Spain); Moreda-Pineiro, Jorge [Department of Analytical Chemistry, Faculty of Sciences, University of A Coruna, Campus da Zapateira, s/n. 15071, A Coruna (Spain); Moreda-Pineiro, Antonio, E-mail: antonio.moreda@usc.es [Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, Avenida das Ciencias, s/n. 15782 - Santiago de Compostela (Spain)

    2012-10-01

    Highlights: Black-Right-Pointing-Pointer Bioavailable iodine and bromine speciation in edible seaweed were developed. Black-Right-Pointing-Pointer In vitro dialyzability was used to assess the bioavailable fractions. Black-Right-Pointing-Pointer AEC hyphenated with inductively coupled plasma-mass spectrometry was used. Black-Right-Pointing-Pointer Iodide, MIT, DIT, bromide and bromate were found in dialyzates from edible seaweed. Black-Right-Pointing-Pointer Positive correlation between bioavailability and protein contents was found. - Abstract: A bioavailability study based on an in vitro dialyzability approach has been applied to assess the bio-available fractions of iodine and bromine species from edible seaweed. Iodide, iodate, 3-iodo-tyrosine (MIT), 3,5-diiodo-tyrosine (DIT), bromide and bromate were separated by anion exchange chromatography under a gradient elution mode (175 mM ammonium nitrate plus 15% (v/v) methanol, pH 3.8, as a mobile phase, and flow rates within the 0.5-1.5 mL min{sup -1} range). Inductively coupled plasma-mass spectrometry (ICP-MS) was used as a selective detector for iodine ({sup 127}I) and bromine ({sup 79}Br). Low dialyzability ratios (within the 2.0-18% range) were found for iodine species; whereas, moderate dialyzability percentages (from 9.0 to 40%) were obtained for bromine species. Iodide and bromide were the major species found in the dialyzates from seaweed, although MIT and bromate were also found in the dialyzates from most of the seaweed samples analysed. However, DIT was only found in dialyzates from Wakame, Kombu, and NIES 09 (Sargasso) certified reference material; whereas, iodate was not found in any dialyzate. Iodine dialyzability was found to be dependent on the protein content (negative correlation), and on the carbohydrate and dietary fibre levels (positive correlation). However, bromine dialyzability was only dependent on the protein amount in seaweed (negative correlation).

  20. Hyphenated LC-MALDI-ToF/ToF and LC-ESI-QToF approach in proteomic characterization of honeybee venom.

    Science.gov (United States)

    Matysiak, Jan; Hajduk, Joanna; Mayer, Franz; Hebeler, Romano; Kokot, Zenon J

    2016-03-20

    To increase in the depth characterization of venom proteome of Apis mellifera the hyphenated LC-MALDI-ToF/ToF-MS (liquid chromatography-matrix-assisted laser desorption/ionization-time of flight/time of flight tandem mass spectrometry) and LC-ESI-QToF-MS (liquid chromatography-electrospray ionization-quadrupole time of flight tandem mass spectrometry) techniques combined with combinatorial peptide ligand library enrichment method is proposed in this study. The novel approach simplifies pretreatment protocol in venom investigation. By using the protein preparation kit with sequential multi-step elution, the honeybee venom was dispensed into four different fractions. In total 269 proteins were detected, among these 49 honeybee toxins, allergens and components involved in mechanism of envenoming belonging to venom enzyme classes of esterases, proteases/peptidases, protease inhibitors, hydrolases and major royal jelly proteins. Moreover 5 additional putative toxins were identified. Their role in envenoming process was discussed. We concluded that different mass spectrometry techniques increased the detection of the honeybee venom proteins, underscoring the complementary character of analytical methods. The combination of MALDI and ESI ionization has resulted in numerous proteins identifications, not possible to reach with single proteomic technique. The study will contribute to broadening the knowledge about the complexity of honeybee venom. The newly identified proteins may serve not only as toxins and allergens, but also as substances with potential pharmacological activity. Although, the most detected proteins belong to trace elements of honeybee venom without toxic activity or action on vital system of victims, they should be taken into account in characterization of living organism response on Apis mellifera sting. PMID:26780156

  1. Speciation of the bio-available iodine and bromine forms in edible seaweed by high performance liquid chromatography hyphenated with inductively coupled plasma-mass spectrometry

    International Nuclear Information System (INIS)

    Highlights: ► Bioavailable iodine and bromine speciation in edible seaweed were developed. ► In vitro dialyzability was used to assess the bioavailable fractions. ► AEC hyphenated with inductively coupled plasma-mass spectrometry was used. ► Iodide, MIT, DIT, bromide and bromate were found in dialyzates from edible seaweed. ► Positive correlation between bioavailability and protein contents was found. - Abstract: A bioavailability study based on an in vitro dialyzability approach has been applied to assess the bio-available fractions of iodine and bromine species from edible seaweed. Iodide, iodate, 3-iodo-tyrosine (MIT), 3,5-diiodo-tyrosine (DIT), bromide and bromate were separated by anion exchange chromatography under a gradient elution mode (175 mM ammonium nitrate plus 15% (v/v) methanol, pH 3.8, as a mobile phase, and flow rates within the 0.5–1.5 mL min−1 range). Inductively coupled plasma-mass spectrometry (ICP-MS) was used as a selective detector for iodine (127I) and bromine (79Br). Low dialyzability ratios (within the 2.0–18% range) were found for iodine species; whereas, moderate dialyzability percentages (from 9.0 to 40%) were obtained for bromine species. Iodide and bromide were the major species found in the dialyzates from seaweed, although MIT and bromate were also found in the dialyzates from most of the seaweed samples analysed. However, DIT was only found in dialyzates from Wakame, Kombu, and NIES 09 (Sargasso) certified reference material; whereas, iodate was not found in any dialyzate. Iodine dialyzability was found to be dependent on the protein content (negative correlation), and on the carbohydrate and dietary fibre levels (positive correlation). However, bromine dialyzability was only dependent on the protein amount in seaweed (negative correlation).

  2. Off-line hyphenation of boronate affinity monolith-based extraction with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for efficient analysis of glycoproteins/glycopeptides.

    Science.gov (United States)

    Bie, Zijun; Chen, Yang; Li, Hengye; Wu, Ronghu; Liu, Zhen

    2014-06-27

    Boronate affinity materials have attracted increasing attentions as sample enrichment platforms for glycoproteomic analysis in recent years. However, most of the boronate affinity materials that have already employed for proteomic analysis are suffering from apparent disadvantages, such as alkaline pH for binding, weak affinity, and relatively poor selectivity. Benzoboroxoles are a unique class of boronic acids which have showed excellent binding properties for the recognition of cis-diol-containing compounds. Recently, a 3-carboxy-benzoboroxole-functionalized monolithic column had been reported and it had exhibited the best selectivity and affinity as well as the lowest binding pH among all reported boronate affinity monolithic columns. In this study, an off-line hyphenation of this boronate affinity monolithic column-based extraction with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was developed and the powerfulness of this hyphenated approach in the analysis of glycoproteins and glycopeptides in complex samples was investigated. The approach was first applied to the analysis of glycopeptides in the tryptic digest of horseradish peroxidase (HRP). Totally 22 glycopeptides were identified. To the best of our knowledge, this is the best performance among all the boronic acid-functionalized materials. We further employed this approach to the analysis of intact proteins in human saliva. Totally 6 intact glycoproteins were successfully identified. As comparison, when the samples were analyzed without extraction, only a few glycopeptides were identified from the tryptic digest of HRP while no glycoproteins were found from the saliva samples. PMID:24928239

  3. On-line ion exchange preconcentration in a sequential injection lab-on-valve microsystem incorporating a renewable column with ETAAS for the trace-level determination of bismuth in urine and river sediment

    DEFF Research Database (Denmark)

    Wang, Jianhua; Hansen, Elo Harald

    2001-01-01

    A sequential injection system for on-line ion-exchange separation and preconcentration of trace-level amounts of metal ions with ensuing detection by electrothermal atomic absorption spectrometry (ETAAS) is described. Based on the use of a renewable microcolumn incorporated within an integrated l...... the determination of 2.0 mug/l Bi (n = 7). The procedure was validated by determination of bismuth in a certified reference material CRM 320 (river sediment), and by bismuth spike recoveries in two human urine samples....

  4. Highly selective micro-sequential injection lab-on-valve (μSI-LOV) method for determination of ultra trace concentrations of nickel in saline matrices using detection by electrothermal atomic absorption spectrometr

    DEFF Research Database (Denmark)

    Long, Xiangbao; Miró, Manuel; Jensen, Rikard;

    2006-01-01

    electrothermal atomic absorption spectrometry (ETAAS). Based on the dimethylglyoxime (DMG) gravimetric procedure used for nickel analysis, the sample, as contained in pH 9.0 buffer, is, after on-line merging with the chelating reagent, transported to a reaction coil attached to one of the external ports of the...

  5. On-line ion exchange preconcentration in a sequential injection lab-on-valve microsystem incorporating a renewable column with ETAAS for the trace-level determination of bismuth in urine and river sediment

    DEFF Research Database (Denmark)

    Wang, Jianhua; Hansen, Elo Harald

    2001-01-01

    A sequential injection system for on-line ion-exchange separation and preconcentration of trace-level amounts of metal ions with ensuing detection by electrothermal atomic absorption spectrometry (ETAAS) is described. Based on the use of a renewable microcolumn incorporated within an integrated lab...

  6. Post-polymerization photografting on methacrylate-based monoliths for separation of intact proteins and protein digests with comprehensive two-dimensional liquid chromatography hyphenated with high-resolution mass spectrometry.

    Science.gov (United States)

    Vonk, Rudy J; Wouters, Sam; Barcaru, Andrei; Vivó-Truyols, Gabriel; Eeltink, Sebastiaan; de Koning, Leo J; Schoenmakers, Peter J

    2015-05-01

    Post-polymerization photografting is a versatile tool to alter the surface chemistry of organic-based monoliths so as to obtain desired stationary phase properties. In this study, 2-acrylamido-2-methyl-1-propanesulfonic acid was grafted to a hydrophobic poly(butyl methacrylate-co-ethylene glycol dimethacrylate) monolith to create a strong cation exchange stationary phase. Both single-step and two-step photografting were addressed, and the effects of grafting conditions were assessed. An experimental design has been applied in an attempt to optimize three of the key parameters of the two-step photografting chemistry, i.e. the grafting time of the initiator, the monomer concentration and the monomer irradiation time. The photografted columns were implemented in a comprehensive two-dimensional column liquid chromatography ( (t) LC ×  (t) LC) workflow and applied for the separation of intact proteins and peptides. A baseline separation of 11 intact proteins was obtained within 20 min by implementing a gradient across a limited RP composition window in the second dimension. (t) LC ×  (t) LC with UV detection was used for the separation of cytochrome c digest, bovine serum insulin digest and a digest of a complex protein mixture. A semi-quantitative estimation of the occupation of separation space, the orthogonality, of the (t) LC ×  (t) LC system yielded 75%. The (t) LC ×  (t) LC setup was hyphenated to a high-resolution Fourier transform ion cyclotron resonance mass spectrometer instrument to identify the bovine serum insulin tryptic peptides and to demonstrate the compatibility with MS analysis. PMID:25801383

  7. Hyphenation of a EC / OC thermal-optical carbon analyzer to photo ionization time-of-flight mass spectrometry: a new off-line aerosol mass spectrometric approach for characterization of primary and secondary particulate matter

    Directory of Open Access Journals (Sweden)

    J. Diab

    2015-01-01

    Full Text Available Source apportionment and exposure of primary and secondary aerosols remains a challenging research field. In particular, the organic composition of primary particles and the formation mechanism of secondary organic aerosols (SOA warrant further investigations. Progress in this field is strongly connected to the development of novel analytical techniques. In this study an off-line aerosol mass spectrometric technique based on filter samples, a hyphenated thermal/optical analyzer-photo ionization time of flight mass spectrometer (PI-TOFMS system, was developed. The approach extends the capability of the widely used PM carbon analysis (for elemental/organic carbon (EC / OC by enabling the investigation of evolved gaseous species with soft and selective (resonance enhanced multiphoton ionization, REMPI and non-selective photo ionization (single photon ionization, SPI techniques. SPI was tuned to be medium soft to achieve comparability with results obtained by electron ionization (EI aerosol mass spectrometer (AMS. Different PM samples including wood combustion emission samples, smog chamber samples from the reaction of ozone with different SOA precursors, and ambient samples taken at Ispra, Italy in winter as well as in summer were tested. The EC / OC-PI-TOFMS technique increases the understanding of the processes during the thermal/optical analysis and identifies marker substances for the source apportionment. Composition of oligomeric or polymeric species present in PM can be investigated by the analysis of the thermally breakdown products. In case of wood combustion, in addition to the well-known markers at m/z ratios of 60 and 73, two new characteristic masses (m/z 70 and 98 have been revealed as potentially linked to biomass burning. All four masses were also the dominant signals in an ambient sample taken in winter time in Ispra, Italy, confirming the finding that wood burning for residential heating is a major source for particulate matter

  8. Hyphenation of a EC / OC thermal-optical carbon analyzer to photo-ionization time-of-flight mass spectrometry: an off-line aerosol mass spectrometric approach for characterization of primary and secondary particulate matter

    Science.gov (United States)

    Diab, J.; Streibel, T.; Cavalli, F.; Lee, S. C.; Saathoff, H.; Mamakos, A.; Chow, J. C.; Chen, L.-W. A.; Watson, J. G.; Sippula, O.; Zimmermann, R.

    2015-08-01

    Source apportionment and characterization of primary and secondary aerosols remains a challenging research field. In particular, the organic composition of primary particles and the formation mechanism of secondary organic aerosols (SOAs) warrant further investigations. Progress in this field is strongly connected to the development of novel analytical techniques. In this study an off-line aerosol mass spectrometric technique based on filter samples, a hyphenated thermal-optical analyzer photo-ionization time-of-flight mass spectrometer (PI-TOFMS) system, was developed. The approach extends the capability of the widely used particulate matter (PM) carbon analysis (for elemental / organic carbon, EC / OC) by enabling the investigation of evolved gaseous species with soft and selective (resonance enhanced multi-photon ionization, REMPI) and non-selective photo-ionization (single-photon ionization, SPI) techniques. SPI was tuned to be medium soft to achieve comparability with results obtained by the electron ionization aerosol mass spectrometer (AMS). Different PM samples including wood combustion emission samples, smog chamber samples from the reaction of ozone with different SOA precursors, and ambient samples taken at Ispra, Italy, in winter as well as in summer were tested. The EC / OC-PI-TOFMS technique increases the understanding of the processes during thermal-optical analysis and identifies marker substances for the source apportionment. Composition of oligomeric or polymeric species present in PM can be investigated by the analysis of the thermal breakdown products. In the case of wood combustion, in addition to the well-known markers at m/z ratios of 60 and 73, two new characteristic masses (m/z 70 and 98) have been revealed as potentially linked to biomass burning. All four masses were also the dominant signals in an ambient sample taken in winter time in Ispra, Italy, confirming the finding that wood burning for residential heating is a major source of PM

  9. Separation and preconcentration of ultratrace levels of cadmium(II) in a sequential injection (SI) system with a PTFE packed column as a mimic sequential injection lab-on-valve (SI-LOV) system with renewable column employing detection by electrothermal atomic absorption spectrometry (ETAAS)

    DEFF Research Database (Denmark)

    Long, Xiangbao; Chomchoei, Roongrat; Gała, Piotr;

    cadmium(II) by detection with electrothermal atomic absorption spectrometry (ETAAS). The non-charged complex formed between the analyste and the chelating reagent diethyldithiophosphate (DDPA) was selectively adsorbed on the surface of the PTFE beads and eluted by ethanol before being directed to the...

  10. Hyphenated techniques for the characterization and quantification of metallothionein isoforms

    Energy Technology Data Exchange (ETDEWEB)

    Prange, Andreas; Schaumloeffel, Dirk [GKSS Research Center, Institute for Coastal Research/Physical and Chemical Analysis, Max-Planck-Strasse, 21502 Geesthacht (Germany)

    2002-07-01

    Recent developments in the coupling of highly selective separation techniques such as capillary electrophoresis (CE) and high-performance liquid chromatography (HPLC) to element-specific and molecule-specific detectors, such as inductively-coupled plasma mass spectrometry (ICP-MS) and electrospray ionization-tandem mass spectrometry (ESI-MS/MS) for the characterization and quantification of metallothioneins (MTs) are critically reviewed and discussed. This review gives an update based on the literature over the last five years. The coupling of CE to ICP-MS is especially highlighted. As a result of progress in new interface technologies for CE-ICP-MS, research topics presented in the literature are changing from ''the characterization of interfaces by metallothioneins'' to the ''characterization of metallothioneins by CE-ICP-MS''. New applications of CE-ICP-MS to the analysis of MTs in real samples are summarized. The potential of the on-line isotope dilution technique for the quantification of MTs and for the determination of the stoichiometric composition of metalloprotein complexes is discussed. Furthermore, a selection of relevant papers dealing with HPLC-ICP-MS for MT analysis are summarized and compared to those dealing with CE-ICP-MS. In particular, the use of size-exclusion (SE)-HPLC as a preliminary separation step for metallothioneins in real samples prior to further chromatographic or electrophoretic separations is considered. Additionally, the application of electrospray ionisation-tandem mass spectrometry (ESI-MS/MS) for the identification of metallothionein isoforms following electrophoretic or chromatographic separation is discussed. (orig.)

  11. Hyphenated ultra high-performance liquid chromatography–Nano Quantity

    Czech Academy of Sciences Publication Activity Database

    Olšovská, Jana; Kameník, Zdeněk; Cajthaml, Tomáš

    2009-01-01

    Roč. 1216, č. 30 (2009), s. 5774-5778. ISSN 0021-9673 R&D Projects: GA MŠk 1M06011 Institutional research plan: CEZ:AV0Z50200510 Keywords : macrolides * uv detection * ultra high-perfonmance liquid chromatography Subject RIV: EE - Microbiology, Virology Impact factor: 4.101, year: 2009

  12. The optimization and validation of sequential injection analysis and sequential injection chromatography methods for some pharmaceuticals

    International Nuclear Information System (INIS)

    The family of flow injection (FI) techniques includes three generations, flow injection analysis (FIA), sequential injection analysis (SIA), and bead injection analysis (BIA). In addition, new versions of SIA, micro-sequential injection-lab-on-valve (μSIA-LOV), and sequential injection chromatography (SIC), have recently been developed. The current study reports the development of four methods for the assay of some pharmaceuticals utilizing flow injection techniques. The methods were validated based on guidelines recommended by the international union of pure and applied chemistry and were then applied to real pharmaceutical samples. The first method was applied for diclofenac assay in various pharmaceutical formulations including tablets, injections and gel. The method was validated and applied to pharmaceutical formulations (tablets, injection and gel). It is recommended to critically optimize effective and interacting conditions using other such optimization tools as response surface and simplex, rather than factorial design that used at initial optimization stage. In the second method a developing oxidation reaction for chlorpromazine by permanganate in acidic media was adopted. Then the method was validated and realized by a British pharmacopoeia methods. It had advantage of high rapidity and was also reagent saving and environmental safety. In the third method, lisinopril (LSP) and hydrochlorothiazide (HCZ) were successfully separated and quantified in tablet formulation using reversed-phase sequential injection liquid chromatography (SIC) coupled with a miniaturized fiber optic spectrometer. The proposed method enjoys outstanding features with respect to analysis time, reagent consumption and safety for the environment. In the fourth method, SIC was exploited for the separation and quantification of sildenafil in tablet formulation. The unique benefits of this method are inexpensive instrumentation, high rapidity, and reagent saving and thus better safety

  13. HYPHENATING IDENTITY OF A TRANSGENDER IN A QUEER FILM CHITHRANGATHA: AN APPRAISAL

    OpenAIRE

    Femina Umar M.

    2016-01-01

    “TORN BETWEEN TWO EXTREAMS...” “Chitrangada: The Crowning Wish” “is a film about the acceptance of a person''s identity. In 2012, Rituparno Ghosh directed and acted in the film Chitrangada, told in a ‘frame-within-frame’ narrative. There Rituparno weaves a web of gender complexities and combines personal experience with myth and fiction.

  14. Pressurised Fluid Extraction of Bioactive Species in Tree Barks : Analysis using Hyphenated Electrochemical Mass Spectrometric Detection

    OpenAIRE

    Co, Michelle

    2010-01-01

    Analytical chemistry has developed throughout time to meet current needs. At present, the interest in biorefinery is growing, due to environmental awareness and the depletion of fossil resources. Biomass from agricultural and forestry industries has proven to be excellent raw material for different processes. Biorefinering valuable species such as bioactive species from biomass, without compromising the primary process of the biomass is highly desirable. Pressurised fluid extraction (PFE) usi...

  15. Four new degradation products of doxorubicin: An application of forced degradation study and hyphenated chromatographic techniques

    Directory of Open Access Journals (Sweden)

    Dheeraj Kaushik

    2015-10-01

    Full Text Available Forced degradation study on doxorubicin (DOX was carried out under hydrolytic condition in acidic, alkaline and neutral media at varied temperatures, as well as under peroxide, thermal and photolytic conditions in accordance with International Conference on Harmonization (ICH guidelines Q1(R2. It was found extremely unstable to alkaline hydrolysis even at room temperature, unstable to acid hydrolysis at 80 °C, and to oxidation at room temperature. It degraded to four products (O-I–O-IV in oxidative condition, and to single product (A-I in acid hydrolytic condition. These products were resolved on a C8 (150 mm×4.6 mm, 5 µm column with isocratic elution using mobile phase consisting of HCOONH4 (10 mM, pH 2.5, acetonitrile and methanol (65:15:20, v/v/v. Liquid chromatography–photodiode array (LC–PDA technique was used to ascertain the purity of the products noted in LC–UV chromatogram. For their characterization, a six stage mass fragmentation (MS6 pattern of DOX was outlined through mass spectral studies in positive mode of electrospray ionization (+ESI as well as through accurate mass spectral data of DOX and the products generated through liquid chromatography–time of flight mass spectrometry (LC–MS–TOF on degraded drug solutions. Based on it, O-I–O-IV were characterized as 3-hydroxy-9-desacetyldoxorubicin-9-hydroperoxide, 1-hydroxy-9-desacetyldoxorubicin-9-hydroperoxide, 9-desacetyldoxorubicin-9-hydroperoxide and 9-desacetyldoxorubicin, respectively, whereas A-I was characterized as deglucosaminyl doxorubicin. While A-I was found to be a pharmacopoeial impurity, all oxidative products were found to be new degradation impurities. The mechanisms and pathways of degradation of doxorubicin were outlined and discussed.

  16. Determination of iodide in samples with complex matrices by hyphenation of capillary isotachophoresis and zone electrophoresis

    Czech Academy of Sciences Publication Activity Database

    Pantůčková, Pavla; Urbánek, Marek; Křivánková, Ludmila

    2007-01-01

    Roč. 28, č. 20 (2007), s. 3777-3785. ISSN 0173-0835 R&D Projects: GA ČR GA203/05/2106; GA AV ČR IAA400310703; GA AV ČR IAA400310609 Institutional research plan: CEZ:AV0Z40310501 Keywords : serum * urine * seawater Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.609, year: 2007

  17. Pharmacokinetic study of inosiplex tablets in healthy Chinese volunteers by hyphenated HPLC and tandem MS techniques

    Institute of Scientific and Technical Information of China (English)

    Mo Chen; Yuan Zhang; Xiao-Ting Que; Ya Ding; Lin Yang; Ai-Dong Wen; Tai-Jun Hang

    2013-01-01

    Inosiplex is a compound formulation composed of inosine and p-acetaminobenzoic acid (PABA) salt of N,N-dimethylamino-2-propanol (DIP). This study was to investigate the clinical plasma pharmacokinetic properties of DIP and PABA after single and multiple oral doses of inosiplex tablets in healthy Chinese volunteers. The established LC/MS/MS method for plasma DIP determination had a linear range of 0.02-10 mg/mL, and the HPLC method for plasma PABA determination had a linear range of 0.05-40 mg/mL. Linear pharmacokinetic characteristics were found with single oral doses of 0.5, 1.0 and 2.0 g. No obvious accumulation effects were observed for DIP and PABA.

  18. Application of Hyphenated Techniques in Speciation Analysis of Arsenic, Antimony, and Thallium

    OpenAIRE

    Rajmund Michalski; Sebastian Szopa; Magdalena Jabłońska; Aleksandra Łyko

    2012-01-01

    Due to the fact that metals and metalloids have a strong impact on the environment, the methods of their determination and speciation have received special attention in recent years. Arsenic, antimony, and thallium are important examples of such toxic elements. Their speciation is especially important in the environmental and biomedical fields because of their toxicity, bioavailability, and reactivity. Recently, speciation analytics has been playing a unique role in the studies of biogeochemi...

  19. Analysis of xanthines in beverages using a fully automated SPE-SPC-DAD hyphenated system

    Energy Technology Data Exchange (ETDEWEB)

    Medvedovici, A. [Bucarest Univ., Bucarest (Romania). Faculty of Chemistry, Dept. of Analytical Chemistry; David, F.; David, V.; Sandra, P. [Research Institute of Chromatography, Kortrijk (Belgium)

    2000-08-01

    Analysis of some xanthines (caffeine, theophylline and theobromine) in beverages has been achieved by a fully automated on-line Solid Phase Extraction - Supercritical Fluid Chromatography - Diode Array Detection (Spe - Sofc - Dad). Three adsorbents have been tested for the Spe procedure: octadecyl modified silicagel (ODS) and two types of styrene-divinylbenzen copolymer based materials, from which Porapack proved to be the most suitable adsorbent. Optimisation and correlation of both Spe and Sofc operational parameters are also discussed. By this technique, caffeine was determined in ice tea and Coca-Cola in a concentration of 0.15 ppm, theobromine - 1.5 ppb, and theophylline - 0.15 ppb. [Italian] Si e' realizzata l'analis di alcune xantine (caffeina, teofillina e teobromina) mediante un sistema, in linea, completamente automatizzato basato su Estrazione in Fase Solida - Cromatografia in Fase Supercritica - Rivelazione con Diode Array (Spe - Sfc - Dad). Per la procedura Spe sono stati valutati tre substrati: silice ottadecilica (ODS) e due tipi di materiali polimerici a base stirene-divinilbenzene, di cui, quello denominato PRP-1, e' risultato essere il piu' efficiente. Sono discusse sia l'ottimizzazione che la correlazione dei parametri operazionali per la Spe e la Sfc. Con questa tecnica sono state determinate, in te' ghiacciato e Coca-Cola, la caffeina, la teobromina e la teofillina alle concentrazini di 0.15, 1.5 e 0.15 ppm.

  20. Dropping the Hyphen? Becoming Latino(a)-American through Racialized Assimilation

    Science.gov (United States)

    Golash-Boza, Tanya

    2006-01-01

    Early assimilation theorists predicted the eventual loss of ethnic distinctiveness for immigrants in the United States. In this paper, the author not only questions the possibilities that Latino and Latina Americans have for losing their ethnic distinctiveness, but also proposes that these possibilities vary widely within the Hispanic population.…

  1. Gas chromatography/ion mobility spectrometry as a hyphenated technique for improved explosives detection and analysis

    Science.gov (United States)

    Mercado, AL; Marsden, Paul

    1995-01-01

    Ion Mobility Spectrometry (IMS) is currently being successfully applied to the problem of on-line trace detection of plastic and other explosives in airports and other facilities. The methods of sample retrieval primarily consist of batch sampling for particulate residue on a filter card for introduction into the IMS. The sample is desorbed into the IMS using air as the carrier and negative ions of the explosives are detected, some as an adduct with a reagent ion such as Cl(-). Based on studies and tests conducted by different airport authorities, this method seems to work well for low vapor pressure explosives such as RDX and PETN, as well as TNT that are highly adsorptive and can be found in nanogram quantities on contaminated surfaces. Recently, the changing terrorist threat and the adoption of new marking agents for plastic explosives has meant that the sample introduction and analysis capabilities of the IMS must be enhanced in order to keep up with other detector developments. The IMS has sufficient analytical resolution for a few threat compounds but the IMS Plasmogram becomes increasingly more difficult to interpret when the sample mixture gets more complex.

  2. Nuclear Proteins Associated with Hyphen Growth in Candida albicans

    OpenAIRE

    Alsheyab Fawzi

    2007-01-01

    Candida albicans is an opportunistic fungus and the most prevalent among human pathogenic yeasts. The Candida spp. are dimorphic fungi with mycelium (M) and budding yeast (B) growth phases. Dimorphism of C. albicans is believed to be a critical component of pathogenesis, to ensure whether the yeast form or the hyphal form is primary responsible for pathogenicity. Growth-form-specific transcripts of C. albicans were characterized using ddRT-PCR to ascertain their fundamental differentiation p...

  3. NMR-based metabolomics and hyphenated NMR techniques – a perfect match in natural products research

    DEFF Research Database (Denmark)

    Vinther, Joachim Møllesøe; Wubshet, Sileshi Gizachew; Stærk, Dan

    2015-01-01

    therapeutics across a range of conditions including CNS disorders, cancer, bone and joint health and parasitic diseases. The final part is devoted to regional perspectives covering all continents, providing a state-of-the –art assessment of the status of ethnopharmacological research globally....

  4. Structural characterization of beer oligosaccharides using hilic chromatography hyphenated with electrospray ionization mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Čmelík, Richard; Bobálová, Janette

    Rome : National Research Council, 2010. s. 159 [International Symposium on Separation Science /16./. 06.09.2010-10.09.2010, Rome] R&D Projects: GA MŠk 2B06037 Institutional research plan: CEZ:AV0Z40310501 Keywords : oligosaccharides * HPLC * beer Subject RIV: CB - Analytical Chemistry, Separation

  5. Development of multidimensional liquid chromatographic methods hyphenated to mass spectrometry, preparation and analysis of complex biological samples

    OpenAIRE

    Delmotte, Nathanaël

    2007-01-01

    Immunoadsorbers based on monolithic epoxy-activated CIM disks have been developed in order to target biomarkers of heart diseases. The developed immunoadsorbers permitted to selectively isolate myoglobin and NT-proBNP from human serum. Anti-NT-proBNP-CIM disks permitted a quantitative isolation of NT-proBNP at concentrations down to 750 amol/µL in serum (R2 = 0.998). Six different restricted access materials have been evaluated with respect to their ability to remove hemoglobin from hemoly...

  6. Neither this nor that: The hyphenated existence of Chinese children growing up in twentieth century North America

    OpenAIRE

    Byrne, Elizabeth

    2005-01-01

    This project takes its evidence from Chinese North American authors who have written about their own lives or those of members of their immigrant community. Authors such as Denise Chong, Wayson Choy, Ben Fong-Torres, Amy Tan, and Yuen-Fong Woon have written autobiographical fictions, fictionalized biographies, and family histories that delve into Chinese communities in Canada and America. These authors have opened windows into the personal worlds of their communities, and this project attempt...

  7. Sustainability Study on Heavy Metal Uptake in Neem Biodiesel Using Selective Catalytic Preparation and Hyphenated Mass Spectrometry

    OpenAIRE

    Mirella Elkadi; Avin Pillay; Johnson Manuel; Mohammad Zubair Khan; Sasi Stephen; Arman Molki

    2014-01-01

    It is common knowledge that the presence of trace metals in biofuels can be detrimental to the environment and long-term sustainable development. This study provides an insight into selective catalytic preparation of biofuel to compare uptake of trace metals in the biodiesel fraction with preferential base catalysts. The role of specific metal hydroxides in controlling trace metal content in biofuel production is relatively unexplored, and the effect of different homogeneous catalysts (NaOH, ...

  8. Hyphenating the curtius rearrangement with Morita-Baylis-Hillman adducts: synthesis of biologically active acyloins and vicinal aminoalcohols

    Energy Technology Data Exchange (ETDEWEB)

    Amarante, Giovanni W.; Cavallaro, Mayra; Coelho, Fernando, E-mail: coelho@iqm.unicamp.b [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Quimica. Lab. de Sintese de Produtos Naturais e Farmacos

    2011-07-01

    Using Morita-Baylis-Hillman adducts as substrates, the Curtius rearrangement was performed in a sequence that allowed the synthesis of several hydroxy-ketones (acyloins) with great structural diversity and in good overall yields. These acyloins in turn were easily transformed into 1,2-anti aminoalcohols through a highly diastereoselective reductive amination step. The synthetic utility of these approaches was exemplified by performing the syntheses of (+-)-bupropion, a drug used to treat the abstinence syndrome of smoker and (+-)-spisulosine, a potent anti-tumoral compound originally isolated from a marine source. (author)

  9. Hyphenating the curtius rearrangement with Morita-Baylis-Hillman adducts: synthesis of biologically active acyloins and vicinal aminoalcohols

    International Nuclear Information System (INIS)

    Using Morita-Baylis-Hillman adducts as substrates, the Curtius rearrangement was performed in a sequence that allowed the synthesis of several hydroxy-ketones (acyloins) with great structural diversity and in good overall yields. These acyloins in turn were easily transformed into 1,2-anti aminoalcohols through a highly diastereoselective reductive amination step. The synthetic utility of these approaches was exemplified by performing the syntheses of (+-)-bupropion, a drug used to treat the abstinence syndrome of smoker and (+-)-spisulosine, a potent anti-tumoral compound originally isolated from a marine source. (author)

  10. Hyphenation of a near-infrared Echelle spectrometer to a microplasma for element-selective detection in gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Cziesla, K.; Otto, M. [Inst. of Analytical Chemistry, Freiberg University of Mining and Technology (Germany); Platzer, B. [Graz Univ. of Technology, Dept. of Analytical Chemistry (Austria); Okruss, M. [Gesellschaft zur Foerderung angewandter Optik, Optoelektronik, Quantenelektronik und Spektroskopie (GOS) e.V., Berlin (Germany); Florek, S. [Inst. of Spectrochemistry and Applied Spectroscopy, Institutsteil Berlin (Germany)

    2001-12-01

    The coupling of a near-infrared Echelle spectrometer (NIRES) with a gas chromatograph for element-selective detection is introduced. The miniaturized capacitive plasma device is operated at a frequency of 40.68 MHz and is mounted directly on an Hewlett-Packard HP6890 GC. First results with a mixture of halogenated standard compounds are presented and discussed in terms of the advantages and problems with this system. (orig.)

  11. Superparamagnetic iron oxide nanoparticles as arsenic adsorbent. Development of Nanofiber SPION Supports and Arsenic Speciation Using Synchrotron and Hyphenated Techniques

    OpenAIRE

    Morillo Martín, Diego

    2013-01-01

    Los estudios que se han realizado en la presente tesis doctoral se basan en el desarrollo de una metodología de síntesis y caracterización de sistemas nanoestructurados como recurso innovador para la recuperación de arsénico en efluentes contaminados y la depuración de dichos efluentes. Estos materiales tienen como elemento común, el uso de las Superparamagnetic Iron Oxide Nanoparticles (SPION), con las que se han realizado diferentes estudios de adsorción para evaluar los parámetros de adsor...

  12. Capillary gas chromatography-ICP mass spectrometry: a powerful hyphenated technique for the determination of organometallic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Smaele, T. de [Laboratory for Analytical Chemistry, Ghent Univ. (Belgium); Moens, L. [Laboratory for Analytical Chemistry, Ghent Univ. (Belgium); Dams, R. [Laboratory for Analytical Chemistry, Ghent Univ. (Belgium); Sandra, P. [Laboratory of Organic Chemistry, Ghent Univ. (Belgium)

    1996-08-01

    The development and improvement of a gas chromatography inductively coupled plasma mass spectrometry system, GC-ICP-MS, is described. The GC and ICP-MS are coupled with a heated stainless steel transfer line. Xe, present in the GC carrier gas, is used to facilitate the nebuliser gas flow rate setting and the positioning of the torch. Alkyltin compounds are separated by GC using a 30 m capillary column within 9 min. The necessity of applying double internal standardisation (use of Bu{sub 3}PeSn and Xe gas as internal standards) is shown. The repeatabilities at 50 {mu}g/l concentration for both retention time and peak are better than 0.25% and 5%, respectively. The detection limits for alkyltin compounds are better than those of existing methods and range between 15 and 35 fg Sn. Finally, GC-ICP-MS is applied to the determination of mono-, di- and tributyltin in some harbour waters, after extraction and Grignard derivation with PrMgCl. Concentrations between 1 and 20 ng/l are found. (orig.). With 5 figs., 6 tabs.

  13. Hyphenated chromatographic techniques for the rapid screening and identification of antioxidants in methanolic extracts of pharmaceutically used plants .

    NARCIS (Netherlands)

    Exarchou, V.; Fiamegos, Y.C.; Beek, van T.A.; Nanos, C.G.; Vervoort, J.J.M.

    2006-01-01

    Phytochemical analysis is an important scientific research area, which normally relies on a number of rather laborious and time-consuming techniques for compound identification. Isolation of the ingredients of plant extracts in adequate quantities for spectral and biological analysis was the basis o

  14. Ionic Liquid and Supercritical Fluid Hyphenated Techniques for Dissolution and Separation of Lanthanides, Actinides, and Fission Products

    International Nuclear Information System (INIS)

    This project is investigating techniques involving ionic liquids (IL) and supercritical (SC) fluids for dissolution and separation of lanthanides, actinides, and fission products. The research project consists of the following tasks: Study direct dissolution of lanthanide oxides, uranium dioxide and other actinide oxides in [bmin][Tf2N] with TBP(HNO3)1.8(H2O)0.6 and similar types of Lewis acid-Lewis base complexing agents; Measure distributions of dissolved metal species between the IL and the sc-CO2 phases under various temperature and pressure conditions; Investigate the chemistry of the dissolved metal species in both IL and sc-CO2 phases using spectroscopic and chemical methods; Evaluate potential applications of the new extraction techniques for nuclear waste management and for other projects. Supercritical carbon dioxide (sc-CO2) and ionic liquids are considered green solvents for chemical reactions and separations. Above the critical point, CO2 has both gas- and liquid-like properties, making it capable of penetrating small pores of solids and dissolving organic compounds in the solid matrix. One application of sc-CO2 extraction technology is nuclear waste management. Ionic liquids are low-melting salts composed of an organic cation and an anion of various forms, with unique properties making them attractive replacements for the volatile organic solvents traditionally used in liquid-liquid extraction processes. One type of room temperature ionic liquid (RTIL) based on the 1-alkyl-3-methylimidazolium cation [bmin] with bis(trifluoromethylsulfonyl)imide anion [Tf2N] is of particular interest for extraction of metal ions due to its water stability, relative low viscosity, high conductivity, and good electrochemical and thermal stability. Recent studies indicate that a coupled IL sc-CO2 extraction system can effectively transfer trivalent lanthanide and uranyl ions from nitric acid solutions. Advantages of this technique include operation at ambient temperature and pressure, selective extraction due to tunable sc-CO2 solvation strength, no IL loss during back-extraction, and no organic solvent introduced into the IL phase

  15. Sustainability Study on Heavy Metal Uptake in Neem Biodiesel Using Selective Catalytic Preparation and Hyphenated Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Mirella Elkadi

    2014-04-01

    Full Text Available It is common knowledge that the presence of trace metals in biofuels can be detrimental to the environment and long-term sustainable development. This study provides an insight into selective catalytic preparation of biofuel to compare uptake of trace metals in the biodiesel fraction with preferential base catalysts. The role of specific metal hydroxides in controlling trace metal content in biofuel production is relatively unexplored, and the effect of different homogeneous catalysts (NaOH, KOH on metal retention in biodiesel from commercial neem oil was examined. A detailed study of this nature of catalyst vs. metal uptake is in the interest of sustainable living and could make a significant contribution to biofuels research. Both catalysts displayed variable uptake for certain toxic elements, which was attributed to the behavior of the catalyst in the reaction mixture. A general comparison reflected specific trends in metal retention (ICP-MS with the use of different base catalysts. Challenges encountered by extending the study and using a heterogeneous catalyst (CaO are presented. Our work could play a significant role in influencing catalyzed transesterfication processes to control elemental and toxic metal uptake in biofuels. The impact of our work on sustainable living is presented.

  16. Flow injection-chemical vapor generation atomic fluorescence spectrometry hyphenated system for organic mercury determination: A step forward

    Energy Technology Data Exchange (ETDEWEB)

    Angeli, Valeria [National Research Council of Italy, C.N.R., Istituto di Chimica dei Composti Organo Metallici - ICCOM-UOS Pisa, Area di Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy); Biagi, Simona [National Research Council of Italy, C.N.R., Istituto per i Processi Chimico-Fisici - IPCF-UOS Pisa, Area di Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy); Ghimenti, Silvia [University of Pisa, Department of Chemistry and Industrial Chemistry, Via Risorgimento 35, 56126 Pisa (Italy); Onor, Massimo; D' Ulivo, Alessandro [National Research Council of Italy, C.N.R., Istituto di Chimica dei Composti Organo Metallici - ICCOM-UOS Pisa, Area di Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy); Bramanti, Emilia, E-mail: bramanti@pi.iccom.cnr.it [National Research Council of Italy, C.N.R., Istituto di Chimica dei Composti Organo Metallici - ICCOM-UOS Pisa, Area di Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy)

    2011-11-15

    Monomethylmercury and ethylmercury were determined on line using flow injection-chemical vapor generation atomic fluorescence spectrometry without neither requiring a pre-treatment with chemical oxidants, nor UV/MW additional post column interface, nor organic solvents, nor complexing agents, such as cysteine. Inorganic mercury, monomethylmercury and ethylmercury were detected by atomic fluorescence spectrometry in an Ar/H{sub 2} miniaturized flame after sodium borohydride reduction to Hg{sup 0}, monomethylmercury hydride and ethylmercury hydride, respectively. The effect of mercury complexing agent such as cysteine, ethylendiaminotetracetic acid and HCl with respect to water and Ar/H{sub 2} microflame was investigated. The behavior of inorganic mercury, monomethylmercury and ethylmercury and their cysteine-complexes was also studied by continuous flow-chemical vapor generation atomic fluorescence spectrometry in order to characterize the reduction reaction with tetrahydroborate. When complexed with cysteine, inorganic mercury, monomethylmercury and ethylmercury cannot be separately quantified varying tetrahydroborate concentration due to a lack of selectivity, and their speciation requires a pre-separation stage (e.g. a chromatographic separation). If not complexed with cysteine, monomethylmercury and ethylmercury cannot be separated, as well, but their sum can be quantified separately with respect to inorganic mercury choosing a suitable concentration of tetrahydroborate (e.g. 10{sup -5} mol L{sup -1}), thus allowing the organic/inorganic mercury speciation. The detection limits of the flow injection-chemical vapor generation atomic fluorescence spectrometry method were about 45 nmol L{sup -1} (as mercury) for all the species considered, a relative standard deviation ranging between 1.8 and 2.9% and a linear dynamic range between 0.1 and 5 {mu}mol L{sup -1} were obtained. Recoveries of monomethylmercury and ethylmercury with respect to inorganic mercury were never less than 91%. Flow injection-chemical vapor generation atomic fluorescence spectrometry method was validated by analyzing the TORT-1 certificate reference material, which contains only monomethylmercury, and obtaining 83 {+-} 5% of monomethylmercury recovered, respectively. This method was also applied to the determination of monomethylmercury in saliva samples. - Highlights: Black-Right-Pointing-Pointer Monomethylmercury and ethylmercury were determined on line using FI-CVG-AFS. Black-Right-Pointing-Pointer No oxidation to Hg{sup II} is required for MeHg and EtHg determination. Black-Right-Pointing-Pointer No complexing agents are needed for their conversion to volatile species detectable by AFS. Black-Right-Pointing-Pointer LOD was about 45 nmol L{sup -1} (as mercury) for all the species considered.

  17. A Hyphenation of Stripping Voltammetry with Electrospray Ionization Mass Spectrometry; an Effect of Sodium Perchlorate on Ferrocene Oxidation

    Czech Academy of Sciences Publication Activity Database

    Jaklová Dytrtová, Jana; Jakl, M.; Navrátil, Tomáš; Schröder, Detlef

    2013-01-01

    Roč. 8, č. 2 (2013), s. 1623-1634. ISSN 1452-3981 R&D Projects: GA ČR GAP206/11/1638 Institutional support: RVO:61388963 ; RVO:61388955 Keywords : ESI-MS * anodic stripping voltammetry * electrochemistry * ferrocene * ferricene * base electrolyte Subject RIV: CG - Electrochemistry Impact factor: 1.956, year: 2013

  18. In situ generation of copper cations and complexation with tebuconazole in a hyphenation of electrochemistry with mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Jaklová Dytrtová, Jana; Jakl, M.; Schröder, Detlef; Norková, Renáta

    2013-01-01

    Roč. 338, 15 MAR (2013), s. 45-49. ISSN 1387-3806 R&D Projects: GA ČR GP13-21409P Institutional support: RVO:61388963 Keywords : electrochemical ion generation * ESI-MS * coupling * fungicide * tebuconazole * soil solution Subject RIV: CG - Electrochemistry Impact factor: 2.227, year: 2013

  19. Extremely sensitive method for determination of iodide in samples with complex matrices using hyphenation of capillary isotachophoresis and zone electrophoresis

    Czech Academy of Sciences Publication Activity Database

    Urbánek, Marek; Křivánková, Ludmila

    Florence : University of Florence, 2004, s. 169. [PBA 2004. International Symposium on Pharmaceutical and Biomedical Analysis /15./. Florence (IT), 02.05.2004-06.05.2004] R&D Projects: GA ČR GA203/02/0023 Institutional research plan: CEZ:AV0Z4031919 Keywords : Iodide * human urine * isotachophoresis-zone electrophoresis Subject RIV: CB - Analytical Chemistry, Separation

  20. Putting Ourselves on the Line: The Epistemology of the Hyphen, Intersubjectivity and Social Responsibility in Qualitative Research

    Science.gov (United States)

    Granek, Leeat

    2013-01-01

    As researchers, we are intertwined in our research relationships in two ways that put us on the line. First, our very beings are co-constituted and developed in an intersubjective exchange with the people we work with. Acknowledging our interdependence frees us to take an empathetic and hermeneutic stance that I have termed the "epistemology…

  1. Four new degradation products of doxorubicin:An application of forced degradation study and hyphenated chromatographic techniques

    Institute of Scientific and Technical Information of China (English)

    Dheeraj Kaushik; Gulshan Bansal

    2015-01-01

    Forced degradation study on doxorubicin (DOX) was carried out under hydrolytic condition in acidic, alkaline and neutral media at varied temperatures, as well as under peroxide, thermal and photolytic conditions in accordance with International Conference on Harmonization (ICH) guidelines Q1(R2). It was found extremely unstable to alkaline hydrolysis even at room temperature, unstable to acid hy-drolysis at 80 °C, and to oxidation at room temperature. It degraded to four products (O-I-O-IV) in oxidative condition, and to single product (A-I) in acid hydrolytic condition. These products were re-solved on a C8 (150 mm × 4.6 mm, 5μm) column with isocratic elution using mobile phase consisting of HCOONH4 (10 mM, pH 2.5), acetonitrile and methanol (65:15:20, / / ). Liquid chromatography-pho-todiode array (LC-PDA) technique was used to ascertain the purity of the products noted in LC-UV chromatogram. For their characterization, a six stage mass fragmentation (MS6) pattern of DOX was outlined through mass spectral studies in positive mode of electrospray ionization (+ESI) as well as through accurate mass spectral data of DOX and the products generated through liquid chromato-graphy-time of flight mass spectrometry (LC-MS-TOF) on degraded drug solutions. Based on it, O-I-O-IV were characterized as 3-hydroxy-9-desacetyldoxorubicin-9-hydroperoxide, 1-hydroxy-9-desacetyldox-orubicin-9-hydroperoxide, 9-desacetyldoxorubicin-9-hydroperoxide and 9-desacetyldoxorubicin, re-spectively, whereas A-I was characterized as deglucosaminyl doxorubicin. While A-I was found to be a pharmacopoeial impurity, all oxidative products were found to be new degradation impurities. The mechanisms and pathways of degradation of doxorubicin were outlined and discussed.

  2. Determination of As in tobacco by using electrochemical hydride generation at a Nafion® solid polymer electrolyte cell hyphenated with atomic fluorescence spectrometry

    Science.gov (United States)

    Yang, Qinghua; Gan, Wuer; Deng, Yun; Sun, Huihui

    2011-11-01

    In the present work, a novel solid polymer electrolyte hydride generation (SPE-HG) cell was developed. The home-made SPE-HG cell, mainly composed of three components (Nafion®117 membrane for separating and H + exchanging, a soft graphite felt cathode and a Ti mesh modified by Ir anode), was employed for detecting As by coupling to atomic fluorescence spectrometry (AFS). The H + generated by electrolysis of pure water in anode chamber transferred to cathode chamber through SPE, and immediately reacted with As 3 + to generate AsH 3. The relative mechanisms and operation conditions for hydride generation of As were investigated in detail. The developed cell employed water as an alternative of acid anolyte, with virtues of low-cost, more than 6 months lifetime and environment friendly compared with the conventional cell. Under the optimized conditions, the limit of determination of As 3 + for sample blank solution was 0.12 μg L - 1 , the RSD was 2.9% for 10 consecutive measurements of 5 μg L - 1 As 3 + standard solution. The accuracy of the method was verified by the determination of As in the reference Tea (GBW07605) and the developed method was successfully applied to determine trace amounts of As in tobacco samples with recovery from 97% to 103%.

  3. Determination of As in tobacco by using electrochemical hydride generation at a Nafion® solid polymer electrolyte cell hyphenated with atomic fluorescence spectrometry

    International Nuclear Information System (INIS)

    In the present work, a novel solid polymer electrolyte hydride generation (SPE-HG) cell was developed. The home-made SPE-HG cell, mainly composed of three components (Nafion®117 membrane for separating and H+ exchanging, a soft graphite felt cathode and a Ti mesh modified by Ir anode), was employed for detecting As by coupling to atomic fluorescence spectrometry (AFS). The H+ generated by electrolysis of pure water in anode chamber transferred to cathode chamber through SPE, and immediately reacted with As3+ to generate AsH3. The relative mechanisms and operation conditions for hydride generation of As were investigated in detail. The developed cell employed water as an alternative of acid anolyte, with virtues of low-cost, more than 6 months lifetime and environment friendly compared with the conventional cell. Under the optimized conditions, the limit of determination of As3+ for sample blank solution was 0.12 μg L−1, the RSD was 2.9% for 10 consecutive measurements of 5 μg L−1 As3+ standard solution. The accuracy of the method was verified by the determination of As in the reference Tea (GBW07605) and the developed method was successfully applied to determine trace amounts of As in tobacco samples with recovery from 97% to 103%.

  4. Determination of As in tobacco by using electrochemical hydride generation at a Nafion Registered-Sign solid polymer electrolyte cell hyphenated with atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Yang Qinghua; Gan Wuer, E-mail: wgan@ustc.edu.cn; Deng Yun; Sun Huihui

    2011-11-15

    In the present work, a novel solid polymer electrolyte hydride generation (SPE-HG) cell was developed. The home-made SPE-HG cell, mainly composed of three components (Nafion Registered-Sign 117 membrane for separating and H{sup +} exchanging, a soft graphite felt cathode and a Ti mesh modified by Ir anode), was employed for detecting As by coupling to atomic fluorescence spectrometry (AFS). The H{sup +} generated by electrolysis of pure water in anode chamber transferred to cathode chamber through SPE, and immediately reacted with As{sup 3+} to generate AsH{sub 3}. The relative mechanisms and operation conditions for hydride generation of As were investigated in detail. The developed cell employed water as an alternative of acid anolyte, with virtues of low-cost, more than 6 months lifetime and environment friendly compared with the conventional cell. Under the optimized conditions, the limit of determination of As{sup 3+} for sample blank solution was 0.12 {mu}g L{sup -1}, the RSD was 2.9% for 10 consecutive measurements of 5 {mu}g L{sup -1} As{sup 3+} standard solution. The accuracy of the method was verified by the determination of As in the reference Tea (GBW07605) and the developed method was successfully applied to determine trace amounts of As in tobacco samples with recovery from 97% to 103%.

  5. Towards early detection of the hydrolytic degradation of poly(bisphenol A)carbonate by hyphenated liquid chromatography and comprehensive two-dimensional liquid chromatography

    NARCIS (Netherlands)

    Coulier, L.; Kaal, E.R.; Hankemeier, Th.

    2006-01-01

    The hydrolytic degradation of poly(bisphenol A)carbonate (PC) has been characterized by various liquid chromatography techniques. Size exclusion chromatography (SEC) showed a significant decrease in molecular mass as a result of hydrolytic degradation, while 'liquid chromatography at critical condit

  6. Simultaneous determination of benzene and phenol in heat transfer fluid by head-space gas chromatography hyphenated with ion mobility spectrometry.

    Science.gov (United States)

    Criado-García, L; Garrido-Delgado, R; Arce, L; López, F; Peón, R; Valcárcel, M

    2015-11-01

    The quantitative determination of some compounds such as benzene and phenol in a complex matrix by ion mobility spectrometry (IMS) can be a difficult task, due to the influence of other components present in the matrix and the chemical properties of both compounds, such as their high volatility and low proton affinity. Monitoring of these compounds in a heat transfer fluid (HTF) is essential to check the correct working of a thermosolar plant and for safety and environmental reasons. Benzene and phenol, among other compounds, are produced when HTF is exposed to high temperatures in continuous cycles and their presence can decrease the efficiency of HTF. For the first time, a headspace module coupled to a gas chromatography column in combination with an IMS (with a tritium ionization source) has been optimized and fully validated to simultaneously quantify benzene and phenol in HTF. The limit of detection (LOD) and limit of quantification (LOQ) achieved with the method proposed were 0.011 and 0.038 g L(-1) and 0.004 and 0.014 g L(-1) for benzene and phenol respectively. The precision of the method was evaluated in terms of repeatability and reproducibility with all values lower than 9.2% and 13.3%, respectively. Results demonstrated that benzene and phenol were generated in the HTF heating process, and its concentration increased with heating time (approximately 483 h). The average concentration values for benzene and phenol in degraded HTF samples were not significantly different to values obtained using a gas chromatography-flame ionization detector instrument. Therefore, IMS is a promising technique for in-field quality control of HTF in a thermosolar plant due to its speed, versatility, sensitivity and selectivity to quantify these degradation compounds. PMID:26452912

  7. Reversed phase liquid chromatography hyphenated to continuous flow-extractive desorption electrospray ionization-mass spectrometry for analysis and charge state manipulation of undigested proteins

    Czech Academy of Sciences Publication Activity Database

    Li, L.; Yang, S.; Vidová, Veronika; Rice, E. M.; Wijeratne, A.; Havlíček, Vladimír; Schug, K. A.

    2015-01-01

    Roč. 21, č. 3 (2015), s. 361-368. ISSN 1469-0667 R&D Projects: GA ČR(CZ) GAP206/12/1150; GA MŠk(CZ) LH14064; GA MŠk LO1509 Institutional support: RVO:61388971 Keywords : protein chromatography * ambient ionization * charge-state manipulation Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.000, year: 2014

  8. Investigation of uranium-colloid interactions in soil by dual field-flow fractionation/capillary electrophoresis hyphenated with inductively coupled plasma-mass spectrometry

    International Nuclear Information System (INIS)

    This paper deals with the study of uranium-colloid interactions in a carbonated soil. The work is focused on the immediately available fraction obtained after a leaching process, according to a normalized batch method. In order to characterize the different colloidal carriers, Asymmetrical Flow Field-Flow Fractionation (As-FI-FFF) coupled to different detectors (UV, Multi Angle laser Light Scattering (MALLS) and Inductively coupled Plasma-Mass Spectrometry (ICP-MS)) was used. The colloidal carriers are mainly inorganic particles (carbonated particles and clays) mixed with organic substances. Furthermore, dissolved and colloidal uranium species in the leaching solutions were monitored by Capillary Electrophoresis (CE) coupled to ICP-MS, in order to investigate the uranium/colloids interactions. According to the first results, uranium fate in this specific soil is controlled by sorption/desorption phenomena, strongly pH dependent. (authors)

  9. Investigation of mercury-containing proteins by enriched stable isotopic tracer and size-exclusion chromatography hyphenated to inductively coupled plasma-isotope dilution mass spectrometry

    International Nuclear Information System (INIS)

    In order to investigate trace mercury-containing proteins in maternal rat and their offspring, a method of enriched stable isotopic tracer (196Hg and 198Hg) combined with size-exclusion chromatography (SEC) coupled to inductively coupled plasma-isotope dilution mass spectrometry (ICP-IDMS) was developed. Prior to the analysis, 196Hg- and 198Hg-enriched methylmercury was administrated to the pregnant rats. Then the mercury-containing proteins in serum and brain cytosol of the dam and pup rats were separated by size-exclusion columns and the mercury was detected by ICP-MS. The ICP-MS spectrogram of the tracing samples showed significantly elevated 196Hg and 198Hg isotopic signals compared with the natural ones, indicating that the detection sensitivity could be increased by the tracer method. The contents of mercury in chromatographic fractions of the dam and pup rat brain cytosol were quantitatively estimated by post-column reverse ID-ICP-MS. The quantitative speciation differences of mercury in brain cytosol between the dam and pup rats were observed, indicating that such studies could be useful for toxicological estimation. Additionally, the isotopic ratio measurement of 198Hg/202Hg in the tracing samples could be used to identify the artifact mercury species caused in the analytical procedure. The study demonstrates that the tracer method combined with high-performance liquid chromatography (HPLC)-ICP-IDMS could provide reliably qualitative and quantitative information on mercury-containing proteins in organisms

  10. Environmental application of elemental speciation analysis based on liquid or gas chromatography hyphenated to inductively coupled plasma mass spectrometry-A review

    International Nuclear Information System (INIS)

    In recent years the number of environmental applications of elemental speciation analysis using inductively coupled plasma mass spectrometry (ICP-MS) as detector has increased significantly. The analytical characteristics, such as extremely low detection limits (LOD) for almost all elements, the wide linear range, the possibility for multi-elemental analysis and the possibility to apply isotope dilution mass spectrometry (IDMS) make ICP-MS an attractive tool for elemental speciation analysis. Two methodological approaches, i.e. the combination of ICP-MS with high performance liquid chromatography (HPLC) and gas chromatography (GC), dominate the field. Besides the investigation of metals and metalloids and their species (e.g. Sn, Hg, As), representing 'classic' elements in environmental science, more recently other elements (e.g. P, S, Br, I) amenable to ICP-MS determination were addressed. In addition, the introduction of isotope dilution analysis and the development of isotopically labeled species-specific standards have contributed to the success of ICP-MS in the field. The aim of this review is to summarize these developments and to highlight recent trends in the environmental application of ICP-MS coupled to GC and HPLC.

  11. Separation and determination of seleno amino acids using gas chromatography hyphenated with inductively coupled plasma mass spectrometry after hollow fiber liquid phase microextraction.

    Science.gov (United States)

    Duan, Jiankun; Hu, Bin

    2009-05-01

    A new derivatization-extraction method for preconcentration of seleno amino acids using hollow fiber liquid phase microextraction (HF-LPME) was developed for the separation and determination of seleno amino acids in biological samples by gas chromatography-inductively coupled plasma mass spectrometry (GC-ICP-MS). Derivatization was performed with ethyl chloroformate (ECF) to improve the volatility of seleno amino acids. Parameters influencing microextraction, including extraction solvent, pH of sample solution, extraction time, stirring speed, and inorganic salt concentration have been investigated. Under the optimal conditions, the limits of detection (LODs) obtained for Se-methyl-selenocysteine (SeMeCys), selenomethionine (SeMet), and selenoethionine (SeEth) were 23, 15, and 11 ng Se l(-1), respectively. The relative standard deviations (RSDs) were 14.6%, 16.4%, and 19.4% for SeMeCys, SeMet, and SeEth (c = 1.0 ng ml(-1), n = 7), respectively, and the RSDs for SeMeCys, SeMet could be improved obviously if SeEth was utilized as the internal standard. The proposed method was applied for the determination of seleno amino acids in extracts of garlic, cabbage, and mushroom samples, and the recoveries for the spiked samples were in the range of 96.8-108% and 93.4-115% with and without the use of SeEth as internal standard. The developed method was also applied to the analysis of SeMet in a certified reference material of SELM-1 yeast and the determined value is in good agreement with the certified value. PMID:19053158

  12. Analytical developments for the determination of monomethylmercury complexes with low molecular mass thiols by reverse phase liquid chromatography hyphenated to inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Bouchet, Sylvain; Björn, Erik

    2014-04-25

    The behavior of monomethylmercury (MMHg) is markedly influenced by its distribution among complexes with low molecular mass (LMM) thiols but analytical methodologies dedicated to measure such complexes are very scarce up to date. In this work, we selected 15 LMM thiols often encountered in living organisms and/or in the environment and evaluated the separation of the 15 corresponding MMHg-thiol complexes by various high performance liquid chromatography (HPLC) columns. Two C18 (Phenomenex Synergi Hydro-RP and LunaC18(2)), two phenyl (Inertsil Ph 3 and 5μm) and one mixed-mode (Restek Ultra IBD) stationary phases were tested for their retention and resolution capacities of the various complexes. The objective was to find simple separation conditions with low organic contents in the mobile phase to provide optimal conditions for detection by inductively coupled plasma mass spectrometry (ICPMS). The 15 complexes were synthesized in solution and characterized by electrospray ionization-mass spectrometry (ESI-MS). The C18 columns tested were either not resolutive enough or too retentive. The 3μm phenyl stationary phase was able to resolve 10 out of the 15 complexes in less than 25min, under isocratic conditions. The mixed-mode column was especially effective at separating the most hydrophilic complexes (6 complexes out of the 15), corresponding to the main LMM thiols found in living organisms. The detection limits (DLs) for these two columns were in the low nanomolar range and overall slightly better for the phenyl column. The possibilities offered by such methodology were exemplified by monitoring the time-course concentrations of four MMHg-thiol complexes within a phytoplankton incubation containing MMHg in the presence of an excess of four added thiols. PMID:24657146

  13. Gas-phase separation of drugs and metabolites using modifier-assisted differential ion mobility spectrometry hyphenated to liquid extraction surface analysis and mass spectrometry.

    Science.gov (United States)

    Porta, Tiffany; Varesio, Emmanuel; Hopfgartner, Gérard

    2013-12-17

    The present work describes an alternative generic approach to LC-MS for the analysis of drugs of abuse as well as their metabolites in post-mortem tissue samples. The platform integrates liquid extraction surface analysis (LESA) for analytes tissue extraction followed by differential ion mobility spectrometry (DMS) mass spectrometry for analytes gas phase separation. Detection is performed on a triple quadrupole linear ion trap using the selected reaction monitoring mode for quantification as well as product ion scan mode for structural confirmatory analyses. The major advantages of the platform are that neither chromatographic separation nor extensive sample preparation are required. In DMS the combination of a high separation voltage (i.e., up to 4 kV) together with organic modifiers (e.g., alcohols, acetonitrile, acetone) added in the drift gas is required to achieve the separation of isomeric metabolites, such as the ones of cocaine and tramadol. DMS also separates morphine from its glucuronide metabolites, which allows for preventing the overestimation of morphine in case of fragmentation of the glucuronides in the atmospheric-to-vacuum interface of the mass spectrometer. Cocaine, opiates, opioids, amphetamines, benzodiazepines and several of their metabolites could be identified in post-mortem human kidney and muscle tissue based on simultaneous screening and confirmatory analysis in data-dependent acquisition mode using an analyte-dependent compensation voltage to selectively transmit ions through the DMS cell to the mass analyzer. Quantitative performance of the LESA-DMS-MS platform was evaluated for cocaine and two of its metabolites spotted onto a tissue section using deuterated internal standard. Analyte's responses were linear from 2 to 1000 pg on tissue corresponding to a limit of detection in the order of nanograms of analyte per gram of tissue. Accuracy and precision based on QC sample was found to be less than 10%. Replicate analyses of cocaine and its metabolites in forensic samples showed an intra- and inter-sections variability of less than 25%. PMID:24251629

  14. Development of a triple hyphenated HPLC-radical scavenging detection-DAD-SPE-NMR system for the rapid identification of antioxidants in complex plant extracts

    NARCIS (Netherlands)

    Pukalskas, A.; Beek, van T.A.; Waard, de P.

    2005-01-01

    A rapid method for the simultaneous detection and identification of radical scavenging compounds in plant extracts was developed by combining an HPLC with on-line radical scavenging using DPPH as a model radical and an HPLC¿DAD¿SPE¿NMR system. Using this method a commercial rosemary extract was inve

  15. Antioxidant Properties and Hyphenated HPLC-PDA-MS Profiling of Chilean Pica Mango Fruits (Mangifera indica L. Cv. piqueño

    Directory of Open Access Journals (Sweden)

    Javier E. Ramirez

    2013-12-01

    Full Text Available Antioxidant capacities and polyphenolic contents of two mango cultivars from northern Chile, one of them endemic of an oasis in the Atacama Desert, were compared for the first time. Twenty one phenolic compounds were detected in peel and pulp of mango fruits varieties Pica and Tommy Atkins by HPLC-PDA-MS and tentatively characterized. Eighteen compounds were present in Pica pulp (ppu, 13 in Pica peel (ppe 11 in Tommy Atkins pulp (tpu and 12 in Tommy Atkins peel (tpe. Three procyanidin dimers (peaks 6, 9 and 10, seven acid derivatives (peaks 1–4, 11, 20 and 21 and four xanthones were identified, mainly mangiferin (peak 12 and mangiferin gallate, (peak 7, which were present in both peel and pulp of the two studied species from northern Chile. Homomangiferin (peak 13 was also present in both fruit pulps and dimethylmangiferin (peak 14 was present only in Tommy pulp. Pica fruits showed better antioxidant capacities and higher polyphenolic content (73.76/32.23 µg/mL in the DPPH assay and 32.49/72.01 mg GAE/100 g fresh material in the TPC assay, for edible pulp and peel, respectively than Tommy Atkins fruits (127.22/46.39 µg/mL in the DPPH assay and 25.03/72.01 mg GAE/100 g fresh material in the TPC assay for pulp and peel, respectively. The peel of Pica mangoes showed also the highest content of phenolics (66.02 mg/100 g FW measured by HPLC-PDA. The HPLC generated fingerprint can be used to authenticate Pica mango fruits and Pica mango food products.

  16. Precise isotope-ratio determination by CGC hyphenated to ICP-MCMS for speciation of trace amounts of gaseous sulfur, with SF6 as example compound.

    Science.gov (United States)

    Krupp, Eva M; Pécheyran, Christophe; Meffan-Main, Simon; Donard, Olivier F X

    2004-01-01

    Capillary gas chromatography coupled to an inductively coupled plasma mass spectrometer with multiple-collector detection (GC-ICP-MCMS) has been used to assess the precision and instrumental mass bias in sulfur isotope-ratio determination for the gaseous sulfur species SF6. The isotopic composition of the compound was certified by the institute for reference materials and measurements (IRMM, Belgium) and is available as PIGS 2010. Integration of the peaks (peak half-width 1.4 s) was performed using a special peak-integration method based on definition of the integration area by assessment of a uniform isotope-ratio area within the chromatographic peak. Instrumental mass bias was determined to be approximately 12% per mass unit and proved to be stable in the concentration range measured. Replicate injections of 2, 10, 20, and 30 ng (as S) SF6 diluted in argon gave precision for the 32S/34S ratio from 0.6% RSD for 2-ng injections to 0.03% RSD for 30-ng injections. The 32S/33S and 33S/34S isotope-ratio precision was better than 0.4% RSD for injections of 10 ng (as S) and higher. Detection limits were in the absolute pg range for all measured sulfur isotopes. PMID:14618293

  17. Characterizing Environmental Transformation of Multi-walled Carbon Nanotubes and Carbon Nano-Fiber Composites using Thermal Analysis and Related Hyphenated Techniques

    Science.gov (United States)

    Thermogravimetric analysis (TGA) coupled with gas chromatography and mass spectroscopy (TGA/GCMS), for the evolved gas analysis, has given insight to the stability and kinetics of structural changes and determining adsorbed organics to nanomaterials and nanocomposites. TGA is als...

  18. Mastering analytical challenges for the characterization of pentacyclic triterpene mono- and diesters of Calendula officinalis flowers by non-aqueous C30 HPLC and hyphenation with APCI-QTOF-MS.

    Science.gov (United States)

    Nicolaus, Christoph; Sievers-Engler, Adrian; Murillo, Renato; D'Ambrosio, Michele; Lämmerhofer, Michael; Merfort, Irmgard

    2016-01-25

    Pentacyclic triterpene mono- and diesters have been isolated from Calendula officinalis flowers. GC-MS, APCI-Exactive Orbitrap HR-MS and NMR allowed to identify the triterpene skeleton in various samples (different triterpene mixtures from Calendula n-hexane extract). NMR provided evidence that triterpene diesters are present in the samples as well. However, the corresponding quasi-molecular ions could not be detected by APCI-Exactive Orbitrap HR-MS. Instability of triterpene diesters and loss of a fatty acid residue, respectively, in the ion-source made their MS detection challenging. Thus, a set of new APCI-QTOF-MS methods (using the TripleTOF 5600+ mass spectrometer) were developed which made it eventually possible to solve this problem and confirm the diester structures by MS via quasi-molecular ion [M+H](+) detection. Direct infusion APCI-QTOF MS experiments in MS/MS high sensitivity scan mode with low collision energy and multi-channel averaging acquisition (MCA) allowed the detection of quasi-molecular ions of triterpene diesters for the first time and unequivocally confirmed the presence of faradiol 3,16-dimyristate and -dipalmitate, as well as the corresponding mixed diesters faradiol 3-myristate,16-palmitate and faradiol 3-palmitate,16-myristate. Preferential loss of the fatty acid in 16-position made it possible to distinguish the mixed diesters by MS/MS spectra. Their chromatographic separations turned out to be challenging due to their bulkiness and extended molecular dimensions. However, separation could be achieved by an uncommon non-aqueous RPLC mode with an in-house synthesized C30 phase. Finally, two (U)HPLC-APCI-QTOF-MS methods with C18- and C30-based non-aqueous RPLC provided suitable, sensitive assays to monitor the presence of monoesters and diesters of various triterpenes (faradiol, maniladiol, arnidiol, arnitriol A and lupane-3β,16β,20-triol esters) in the n-hexane extract of C. officinalis with high mass resolution and good mass accuracy. PMID:26562182

  19. Asymmetric Flow-Field Flow Fractionation Hyphenated ICP-MS as an Alternative to Cloud Point Extraction for Quantification of Silver Nanoparticles and Silver Speciation: Application for Nanoparticles with a Protein Corona.

    Science.gov (United States)

    Mudalige, Thilak K; Qu, Haiou; Linder, Sean W

    2015-07-21

    Production and application of nanoparticles in consumer products is at an all-time high due to the emerging field of nanotechnology. Direct detection and quantification of trace levels of nanoparticles within consumer products is very challenging and problematic. Although multiple methodologies are available for this purpose, each method has its own set of limitations. Herein, we developed an analytical platform consisting of asymmetric flow-field flow fractionation (AF4) coupled with inductively coupled plasma mass spectroscopy (ICP-MS) for the speciation and quantification of silver ions and silver nanoparticles at the ng/kg level (ppt). AF4 is utilized to concentrate the nanoparticles, and ICP-MS acts as the detector. The protein corona that forms upon exposure of nanoparticles to bovine serum albumin was utilized as a nanoparticle stabilization and AF4 recovery enhancement mechanism. Speciation of silver ions and nanoparticles was achieved with the assistance of penicillamine as a complexation ligand. The effect of nanoparticle size, surface coating, and ionization state toward the detection and quantification of the developed methodology was evaluated. The detection limit was found to be 4 ng/kg with the application of a 5 mL sample loop. Further application of this developed methodology on environmentally relevant samples was demonstrated by the analysis of Arkansas River water spiked with silver nanoparticles and nanoparticle spiked into humic acid solution (50 mg/L) at an environmentally relevant level. PMID:26095720

  20. How Flow Injection Analysis (FIA) over the past 25 years has changed our way of performing chemical analyses

    DEFF Research Database (Denmark)

    Hansen, Elo Harald; Miró, Manuel

    2007-01-01

    Briefly looking back on the impact of flow injection analysis (FIA), as reflected in the rapid growth of publications in the scientific literature, and touching upon many of the novel and unique analytical chemical possibilities that FIA and its sequels, sequential injection analysis (SIA) and Lab......-on-Valve (LOV), have offered, we emphasize assays based on kinetic discrimination schemes, where, even subtle, differences in the reaction rates of the chemical reactions that occur are judiciously exploited. We give a number of examples, covering homogeneous as well as heterogeneous conversions techniques...

  1. Are Flow Injection-based Approaches Suitable for Automated Handling of Solid Samples?

    DEFF Research Database (Denmark)

    Miró, Manuel; Hansen, Elo Harald; Cerdà, Victor

    electrolytic or aqueous leaching, on-line dialysis/microdialysis, in-line filtration, and pervaporation-based procedures have been successfully implemented in continuous flow/flow injection systems. In this communication, the new generation of flow analysis, including sequential injection, multicommutated flow......, multisyringe flow injection, and micro-Lab-on-valve are presented as appealing approaches for on-line handling of solid samples. Special emphasis is given to the capability of flow systems to accommodate sequential extraction protocols for partitioning of trace elements and nutrients in environmental solids (e.......g., soils, sediments, sludges), and thus, ascertaining the potential mobility, bioavailability and eventual impact of anthropogenic elements on biota [2]. In this context, the principles of sequential injection-microcolumn extraction (SI-MCE) for dynamic fractionation are explained in detail along with the...

  2. ACTINET-I3 Summer School on Analytical Innovation in the field of actinide recycling - Slides of the presentations

    International Nuclear Information System (INIS)

    This conference dealt with 3 main topics: analytical innovation in separation processes (hyphenated techniques, analytical chips,...), actinide recycling (extraction, interfaces, processes,...) and chemistry and thermodynamics of actinides. This document is composed of the slides of the presentations

  3. On-line sample processing methods in flow analysis

    DEFF Research Database (Denmark)

    Miró, Manuel; Hansen, Elo Harald

    2008-01-01

    -line dilution, derivatization, separation and preconcentration methods encompassing solid reactors, solvent extraction, sorbent extraction, precipitation/coprecipitation, hydride/vapor generation and digestion/leaching protocols as hyphenated to a plethora of detection devices is discussed in detail and...

  4. CLEAN_LNAME: Stata module to clean lastname variables

    OpenAIRE

    Adrien Bouguen

    2015-01-01

    This program removes blanks, accents, full stops, hyphens and apostrophes within a string variable. It also returns the uppercased version of the variable. clean_lname (together with clean_fname) is particularly useful for name matching procedure.

  5. CLEAN_FNAME: Stata module to clean firstname variables

    OpenAIRE

    Adrien Bouguen

    2015-01-01

    This program removes blanks, accents, full stops, hyphens and apostrophes from a string variable. It returns the proper version of the variable. clean_fname (together with clean_lname) is particularly useful for name matching procedure.

  6. Normal Pancreas Anatomy

    Science.gov (United States)

    ... hyphen, e.g. -historical Searches are case-insensitive Pancreas Anatomy Add to My Pictures View /Download : Small: ... 1586x1534 View Download Large: 3172x3068 View Download Title: Pancreas Anatomy Description: Anatomy of the pancreas; drawing shows ...

  7. 77 FR 44144 - National Forest System Land Management Planning; Correction

    Science.gov (United States)

    2012-07-27

    ..., (77 FR 21162). Errors have been found in the rule with respect to punctuation, hyphenation, and.... * * * (4) Cultural services, such as educational, aesthetic, spiritual and cultural heritage values, recreational experiences, and tourism opportunities. * * * * * Source water protection areas. The...

  8. Mecánica estadística, neodarwinismo y la prefiguración de las ciencias de la complejidad

    OpenAIRE

    Andrade Luis Eugenio

    2009-01-01

  1. Granulomatous peritonitis due to Ascaris lumbricoides. Case report Granulomatosis peritoneal por Ascaris lumbricoides.Presentación de un caso

    OpenAIRE

    Carlos Aguirre Muñoz; Alberto Bustamante Gallego; Blair Ortiz Giraldo; Elvia Góez Gutiérrez

    2008-01-01

  1. On-line sample-pre-treatment schemes for trace-level determinations of metals by coupling flow injection or sequential injection with ICP-MS

    DEFF Research Database (Denmark)

    Wang, Jianhua; Hansen, Elo Harald

    2003-01-01

    polytetrafluoroethylene (PTFE) knotted reactor (KR), solvent extraction-back extraction and hydride/vapor generation. It also addresses a novel, robust approach, whereby the protocol of SI-LOV-bead injection (BI) on-line separation and pre-concentration of ultra-trace levels of metals by a renewable microcolumn is...... on-line matrix separation and pre-concentration of trace levels of metals with detection by ICP-MS. It highlights some of the frequently applied on-line, sample-pre-treatment schemes, including solid phase extraction (SPE), on-wall molecular sorption and precipitate/(co)-precipitate retention using a...

  2. Recent developments in automatic solid-phase extraction with renewable surfaces exploiting flow-based approaches

    DEFF Research Database (Denmark)

    Miró, Manuel; Hartwell, Supaporn Kradtap; Jakmunee, Jaroon; Grudpan, Kate; Hansen, Elo Harald

    2008-01-01

    Solid-phase extraction (SPE) is the most versatile sample-processing method for removal of interfering species and/or analyte enrichment. Although significant advances have been made over the past two decades in automating the entire analytical protocol involving SPE via flow-injection approaches...... overcoming the above shortcomings, so-called bead-injection (BI) analysis, based on automated renewal of the sorbent material per assay exploiting the various generations of flow-injection analysis. It addresses novel instrumental developments for implementing BI and a number of alternatives for online...

  3. Venom of Parasitoid Pteromalus puparum Impairs Host Humoral Antimicrobial Activity by Decreasing Host Cecropin and Lysozyme Gene Expression

    Science.gov (United States)

    Fang, Qi; Wang, Bei-Bei; Ye, Xin-Hai; Wang, Fei; Ye, Gong-Yin

    2016-01-01

    Insect host/parasitoid interactions are co-evolved systems in which host defenses are balanced by parasitoid mechanisms to disable or hide from host immune effectors. Here, we report that Pteromalus puparum venom impairs the antimicrobial activity of its host Pieris rapae. Inhibition zone results showed that bead injection induced the antimicrobial activity of the host hemolymph but that venom inhibited it. The cDNAs encoding cecropin and lysozyme were screened. Relative quantitative PCR results indicated that all of the microorganisms and bead injections up-regulated the transcript levels of the two genes but that venom down-regulated them. At 8 h post bead challenge, there was a peak in the transcript level of the cecropin gene, whereas the peak of lysozyme gene occurred at 24 h. The transcripts levels of the two genes were higher in the granulocytes and fat body than in other tissues. RNA interference decreased the transcript levels of the two genes and the antimicrobial activity of the pupal hemolymph. Venom injections similarly silenced the expression of the two genes during the first 8 h post-treatment in time- and dose-dependent manners, after which the silence effects abated. Additionally, recombinant cecropin and lysozyme had no significant effect on the emergence rate of pupae that were parasitized by P. puparum females. These findings suggest one mechanism of impairing host antimicrobial activity by parasitoid venom. PMID:26907346

  4. Venom of Parasitoid Pteromalus puparum Impairs Host Humoral Antimicrobial Activity by Decreasing Host Cecropin and Lysozyme Gene Expression.

    Science.gov (United States)

    Fang, Qi; Wang, Bei-Bei; Ye, Xin-Hai; Wang, Fei; Ye, Gong-Yin

    2016-01-01

    Insect host/parasitoid interactions are co-evolved systems in which host defenses are balanced by parasitoid mechanisms to disable or hide from host immune effectors. Here, we report that Pteromalus puparum venom impairs the antimicrobial activity of its host Pieris rapae. Inhibition zone results showed that bead injection induced the antimicrobial activity of the host hemolymph but that venom inhibited it. The cDNAs encoding cecropin and lysozyme were screened. Relative quantitative PCR results indicated that all of the microorganisms and bead injections up-regulated the transcript levels of the two genes but that venom down-regulated them. At 8 h post bead challenge, there was a peak in the transcript level of the cecropin gene, whereas the peak of lysozyme gene occurred at 24 h. The transcripts levels of the two genes were higher in the granulocytes and fat body than in other tissues. RNA interference decreased the transcript levels of the two genes and the antimicrobial activity of the pupal hemolymph. Venom injections similarly silenced the expression of the two genes during the first 8 h post-treatment in time- and dose-dependent manners, after which the silence effects abated. Additionally, recombinant cecropin and lysozyme had no significant effect on the emergence rate of pupae that were parasitized by P. puparum females. These findings suggest one mechanism of impairing host antimicrobial activity by parasitoid venom. PMID:26907346

  5. Venom of Parasitoid Pteromalus puparum Impairs Host Humoral Antimicrobial Activity by Decreasing Host Cecropin and Lysozyme Gene Expression

    Directory of Open Access Journals (Sweden)

    Qi Fang

    2016-02-01

    Full Text Available Insect host/parasitoid interactions are co-evolved systems in which host defenses are balanced by parasitoid mechanisms to disable or hide from host immune effectors. Here, we report that Pteromalus puparum venom impairs the antimicrobial activity of its host Pieris rapae. Inhibition zone results showed that bead injection induced the antimicrobial activity of the host hemolymph but that venom inhibited it. The cDNAs encoding cecropin and lysozyme were screened. Relative quantitative PCR results indicated that all of the microorganisms and bead injections up-regulated the transcript levels of the two genes but that venom down-regulated them. At 8 h post bead challenge, there was a peak in the transcript level of the cecropin gene, whereas the peak of lysozyme gene occurred at 24 h. The transcripts levels of the two genes were higher in the granulocytes and fat body than in other tissues. RNA interference decreased the transcript levels of the two genes and the antimicrobial activity of the pupal hemolymph. Venom injections similarly silenced the expression of the two genes during the first 8 h post-treatment in time- and dose-dependent manners, after which the silence effects abated. Additionally, recombinant cecropin and lysozyme had no significant effect on the emergence rate of pupae that were parasitized by P. puparum females. These findings suggest one mechanism of impairing host antimicrobial activity by parasitoid venom.

  6. A CONVERSÃO DE CONHECIMENTO ATRAVÉS DO “LEARNING BY HIRING” NO PROGRAMA EMBRAER 170/190

    OpenAIRE

    Ricardo Gentil Peixoto da Costa; Henrique Pazos Siqueira Boclin; Luiz Alberto Nascimento Campos Filho

    2008-01-01

    Shared Task System Description: Frustratingly Hard Compositionality Prediction

    DEFF Research Database (Denmark)

    Johannsen, Anders Trærup; Martinez Alonso, Hector; Rishøj, Christian;

    2011-01-01

    We considered a wide range of features for the DiSCo 2011 shared task about compositionality prediction for word pairs, including COALS-based endocentricity scores, compositionality scores based on distributional clusters, statistics about wordnet-induced paraphrases, hyphenation, and the likelih...

  7. Limits of determination of the weight-to-number average molecular-weight ratio by size exclusion chromatography with the dual light-scattering/concentration detection

    Czech Academy of Sciences Publication Activity Database

    Netopilík, Miloš; Podzimek, Š.; Kratochvíl, Pavel

    Bratislava : Polymer Institute of the Slovak Academy of Sciences, 2001. s. 35-36. ISBN 80-968591-3-7. [International Bratislava Meeting on Polymers /16./. Coupled, Hyphenated and Multidimentional Liquid Chromatographic Procedures for Separation of Macromolecules.. 09.09.2001-13.09.2001, Bratislava] R&D Projects: GA AV ČR KSK4050111 Subject RIV: CD - Macromolecular Chemistry

  8. Instrument and process independent binning and baseline correction methods for liquid chromatography-high resolution-mass spectrometry deconvolution

    NARCIS (Netherlands)

    Krishnan, S.; Vogels, J.T.W.E.; Coulier, L.; Bas, R.C.; Hendriks, M.W.B.; Hankemeier, T.; Thissen, U.

    2012-01-01

    Setting appropriate bin sizes to aggregate hyphenated high-resolution mass spectrometry data, belonging to similar mass over charge (m/. z) channels, is vital to metabolite quantification and further identification. In a high-resolution mass spectrometer when mass accuracy (ppm) varies as a function

  9. A multivariate statistical analysis approach to analyze gas chromatography-olfactometry data of tangerine hybrids

    Science.gov (United States)

    Gas chromatography (GC) hyphenated with olfactometry (O) when a human subject smells the effluent of the GC is a useful technique to identify aroma activity of volatile compounds in a food. Many techniques have been developed, based on olfactory thresholds (CHARM analysis, AEDA), or based on psychop...

  10. Electrochemical activation and separation cell prior mass spectrometry detection

    Czech Academy of Sciences Publication Activity Database

    Jaklová Dytrtová, Jana; Jakl, M.; Navrátil, Tomáš; Cvačka, Josef; Pačes, Ondřej

    Munich : -, 2014. [BioVaria 2014. 06.05.2014, Munich] R&D Projects: GA ČR GP13-21409P; GA ČR(CZ) GAP208/12/1645 Institutional support: RVO:61388963 ; RVO:61388955 Keywords : electrochemical flow cell * ESI-MS * hyphenation * ion generation Subject RIV: CF - Physical ; Theoretical Chemistry

  11. Electrochemical activation and separation cell prior detection using mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Jaklová Dytrtová, Jana; Jakl, M.; Navrátil, Tomáš; Cvačka, Josef; Pačes, Ondřej

    Munich : -, 2014. [BioVaria 2014. 06.05.2014, Munich] R&D Projects: GA ČR GP13-21409P; GA ČR(CZ) GAP208/12/1645 Institutional support: RVO:61388963 ; RVO:61388955 Keywords : electrochemical flow cell * ESI-MS * hyphenation * ion generation Subject RIV: CF - Physical ; Theoretical Chemistry

  12. Eletroforese capilar acoplada à espectrometria com plasma: uma ferramenta eficiente para a especiação Capillary electrophoresis coupled to plasma spectrometry: an efficient tool for speciation

    Directory of Open Access Journals (Sweden)

    Ana Paula G. Gervasio

    2003-01-01

    Full Text Available The most important features of the CE-ICP hyphenation, as well as its advantages and drawbacks as a tool for speciation are discussed. The fundamental principles of capillary electrophoresis and inductively coupled plasma mass spectrometry are also presented. Some applications involving different designs proposed in the literature to couple CE and ICP system for elemental speciation are reviewed.

  13. Automated sequential injection-microcolumn approach with on-line flame atomic absorption spectrometric detection for implementing metal fractionation schemes of homogeneous and non-homogeneous solid samples of environmental interest

    DEFF Research Database (Denmark)

    Chomchoei, Roongrat; Miró, Manuel; Hansen, Elo Harald;

    2005-01-01

    spectrometric detection and used for the determination of Cu as a model analyte, the potentials of this novel hyphenated approach are demonstrated by the ability of handling up to 300 mg sample of a nonhomogeneous sewage amended soil (viz., CRM 483). The three steps of the endorsed Standards, Measurements, and...

  14. Observation of whispering gallery modes in the mid-infrared with a quantum cascade laser: possible applications to nanoliter chemical sensing

    OpenAIRE

    Wu, Sheng; Deev, Andrei

    2009-01-01

    Excitation of the whispering gallery modes (WGM) of a CaF_2 ball resonator is demonstrated at 4.5 micron with a pulsed Quantum Cascade laser. A prism coupling scheme for mid-infrared is described. Future applications of WGM resonators as hyphenated inline chromatography sensors are discussed.

  1. Punctuation Potpourri. An Office Education Mini Curriculum Manual on Other Punctuation Marks.

    Science.gov (United States)

    Hawkinson, Bruce

    One in a series of ten mini-manuals on office communication proofreading, this booklet for business and office students provides instruction in the use of apostrophes, quotes, italics, hyphens, brackets, ellipsis dots, leader dots, bullets, superscripts, and subscripts. Included are terminal and specific objectives, punctuation rules and related…

  2. Eletroforese capilar acoplada à espectrometria com plasma: uma ferramenta eficiente para a especiação Capillary electrophoresis coupled to plasma spectrometry: an efficient tool for speciation

    OpenAIRE

    Ana Paula G. Gervasio; André F. Lavorante; Maria Carolina B. Moraes; Maria Fernanda Giné; Carlos E. S. Miranda; Emanuel Carrilho

    2003-01-01

    The most important features of the CE-ICP hyphenation, as well as its advantages and drawbacks as a tool for speciation are discussed. The fundamental principles of capillary electrophoresis and inductively coupled plasma mass spectrometry are also presented. Some applications involving different designs proposed in the literature to couple CE and ICP system for elemental speciation are reviewed.

  3. Good taste: the embodied normativity of the consumer-citizen

    NARCIS (Netherlands)

    A. Mol

    2009-01-01

    In political theory citizens are defined as being willing to serve the 'common good' while consumers are supposed to seek 'pleasure'. The two terms pull in different directions, so that adding a hyphen is not enough to craft a figure capable of acting in ways that are generous as well as gratifying.

  4. Bayesian networks for omics data analysis

    NARCIS (Netherlands)

    Gavai, A.K.

    2009-01-01

    This thesis focuses on two aspects of high throughput technologies, i.e. data storage and data analysis, in particular in transcriptomics and metabolomics. Both technologies are part of a research field that is generally called ‘omics’ (or ‘-omics’, with a leading hyphen), which refers to genomics,

  5. Detection of Phenolic and Flavonoid Compounds Using High Performance Thin Layer Chromatography (HPTLC).

    Science.gov (United States)

    2016-01-01

    High performance thin layer chromatography (HPTLC) is a sophisticated instrumental technique based on the full capabilities of thin layerchromatography. The advantages of automation, scanning, full optimization, selective detection principle, minimum sample preparation,hyphenation, etc., enable it to be a powerful analytical tool for chromatographic information of complex mixtures of inorganic, organic andbiomolecules which are characterized in this chapter. PMID:26939287

  6. Trends and perspectives of flow injection/sequential injection on-line sample-pretreatment schemes coupled to ETAAS

    DEFF Research Database (Denmark)

    Wang, Jianhua; Hansen, Elo Harald

    2005-01-01

    recent decades is amply demonstrated by the large number of publications to which is has given rise. Among these, its hyphenation with electrothermal atomic absorption spectrometry (ETAAS) is one of the most attractive sub-branches because of the high sensitivity of ETAAS instruments for metal species...

  7. Orthographe: la fin d'un tabou (Orthography: The End of a Taboo).

    Science.gov (United States)

    Olivieri, Claude

    1990-01-01

    Significant features of the official October 1990 orthographic reforms in French are outlined and their pedagogical implications are discussed briefly. The changes, primarily simplifications and not major changes, affect use of the hyphen, plurals, diacritical markings, verb tenses, and correction of anomalies. (MSE)

  8. The Development of Whole-Word Representations in Compound Word Processing: Evidence from Eye Fixation Patterns of Elementary School Children

    Science.gov (United States)

    Haikio, Tuomo; Bertram, Raymond; Hyona, Jukka

    2011-01-01

    The role of morphology in reading development was examined by measuring participants' eye movements while they read sentences containing either a hyphenated (e.g., "ulko-ovi" "front door") or concatenated (e.g., "autopeli" "racing game") compound. The participants were Finnish second, fourth, and sixth graders (aged 8, 10, and 12 years,…

  9. From retrospective assessment to prospective decisions in natural product isolation

    DEFF Research Database (Denmark)

    Johansen, Kenneth T; Wubshet, Sileshi G; Nyberg, Nils T;

    2011-01-01

    natural products. While the nontarget fractionation involved considerable time spent on pursuing fractions containing well-known or undesired compounds, the hyphenated analysis was considerably faster and required less solvent and other consumables. The results were used to design and execute an optimized...

  10. Determination of 90Sr and 210Pb in sludge samples using a LOV-MSFIA system and liquid scintillation counting

    International Nuclear Information System (INIS)

    There has been increasing interest recently in the capacity of water treatment plants to concentrate and eliminate radionuclides from raw water. As the normal operation in these plants generates high quantities of sludge, which can be considered a naturally occurring radioactive material, it is important to gather information about its radiological content. Therefore, in order to determine the activity values of two radioactive beta emitters with minimal sample manipulation, an automated lab-on-valve and multisyringe flow injection system has been developed to achieve the sequential preconcentration and separation of 90Sr and 210Pb using an extraction chromatographic resin (Sr-spec). Activities of both isotopes were measured by liquid scintillation counting (LSC). The developed method was validated by analyzing three samples from three different intercomparison exercises and good Z-score values (between 0.1 and 1) and trueness values (between 10% and 17%) were obtained. The method was then also satisfactorily applied to sludge samples taken from a Spanish drinking water treatment plant which treats water from the Ebro River. The proposed method offers advantages over existing methods as it allows the sequential separation of both isotopes, simply by changing the elution conditions and using a semi-automated approach. Therefore, the method is less time consuming and environmentally friendly. - Highlights: • Flow system methodologies have been developed for the sequential separation of 90Sr and 210Pb. • Two radioactive beta emitters are determined with minimum sample manipulation. • Sludge samples from DWTP which were considered to be NORM samples have been analyzed. • Activities of both isotopes have been measured by liquid scintillation counting

  11. On-line liquid phase micro-extraction based on drop-in-plug sequential injection lab-at-valve platform for metal determination

    International Nuclear Information System (INIS)

    Highlights: ► Drop-in-plug micro-extraction based on SI-LAV platform for metal preconcentration. ► Automatic liquid phase micro-extraction coupled with FAAS. ► Organic solvents with density higher than water are used. ► Lead determination in environmental water and urine samples. -- Abstract: A novel automatic on-line liquid phase micro-extraction method based on drop-in-plug sequential injection lab-at-valve (LAV) platform was proposed for metal preconcentration and determination. A flow-through micro-extraction chamber mounted at the selection valve was adopted without the need of sophisticated lab-on-valve components. Coupled to flame atomic absorption spectrometry (FAAS), the potential of this lab-at-valve scheme is demonstrated for trace lead determination in environmental and biological water samples. A hydrophobic complex of lead with ammonium pyrrolidine dithiocarbamate (APDC) was formed on-line and subsequently extracted into an 80 μL plug of chloroform. The extraction procedure was performed by forming micro-droplets of aqueous phase into the plug of the extractant. All critical parameters that affect the efficiency of the system were studied and optimized. The proposed method offered good performance characteristics and high preconcentration ratios. For 10 mL sample consumption an enhancement factor of 125 was obtained. The detection limit was 1.8 μg L−1 and the precision expressed as relative standard deviation (RSD) at 50.0 μg L−1 of lead was 2.9%. The proposed method was evaluated by analyzing certified reference materials and applied for lead determination in natural waters and urine samples

  12. MSFIA-LOV system for (226)Ra isolation and pre-concentration from water samples previous radiometric detection.

    Science.gov (United States)

    Rodríguez, Rogelio; Borràs, Antoni; Leal, Luz; Cerdà, Víctor; Ferrer, Laura

    2016-03-10

    An automatic system based on multisyringe flow injection analysis (MSFIA) and lab-on-valve (LOV) flow techniques for separation and pre-concentration of (226)Ra from drinking and natural water samples has been developed. The analytical protocol combines two different procedures: the Ra adsorption on MnO2 and the BaSO4 co-precipitation, achieving more selectivity especially in water samples with low radium levels. Radium is adsorbed on MnO2 deposited on macroporous of bead cellulose. Then, it is eluted with hydroxylamine to transform insoluble MnO2 to soluble Mn(II) thus freeing Ra, which is then coprecipitated with BaSO4. The (226)Ra can be directly detected in off-line mode using a low background proportional counter (LBPC) or through a liquid scintillation counter (LSC), after performing an on-line coprecipitate dissolution. Thus, the versatility of the proposed system allows the selection of the radiometric detection technique depending on the detector availability or the required response efficiency (sample number vs. response time and limit of detection). The MSFIA-LOV system improves the precision (1.7% RSD), and the extraction frequency (up to 3 h(-1)). Besides, it has been satisfactorily applied to different types of water matrices (tap, mineral, well and sea water). The (226)Ra minimum detectable activities (LSC: 0.004 Bq L(-1); LBPC: 0.02 Bq L(-1)) attained by this system allow to reach the guidance values proposed by the relevant international agencies e.g. WHO, EPA and EC. PMID:26893088

  13. Gas Chromatography/Atmospheric Pressure Chemical Ionization-Fourier Transform Ion Cyclotron Resonance Mass Spectrometry of Pyrolysis Oil from German Brown Coal.

    Science.gov (United States)

    Zuber, Jan; Kroll, Marius M; Rathsack, Philipp; Otto, Matthias

    2016-01-01

    Pyrolysis oil from the slow pyrolysis of German brown coal from Schöningen, obtained at a temperature of 500°C, was separated and analyzed using hyphenation of gas chromatography with an atmospheric pressure chemical ionization source operated in negative ion mode and Fourier transform ion cyclotron resonance mass spectrometry (GC-APCI-FT-ICR-MS). Development of this ultrahigh-resolving analysis method is described, that is, optimization of specific GC and APCI parameters and performed data processing. The advantages of GC-APCI-FT-ICR-MS hyphenation, for example, soft ionization, ultrahigh-resolving detection, and most important isomer separation, were demonstrated for the sample liquid. For instance, it was possible to separate and identify nine different propylphenol, ethylmethylphenol, and trimethylphenol isomers. Furthermore, homologous series of different acids, for example, alkyl and alkylene carboxylic acids, were verified, as well as homologous series of alkyl phenols, alkyl dihydroxy benzenes, and alkoxy alkyl phenols. PMID:27066076

  14. New Oxford style manual

    CERN Document Server

    2012-01-01

    The New Oxford Style Manual brings together two essential reference works in a single volume: New Hart's Rules and the New Oxford Dictionary for Writers and Editors. New Hart's Rules, Oxford's definitive guide to style, consists of 20 chapters that provide authoritative and expert advice on how to prepare copy for publication. Topics covered include how to use italic, roman, and other type treatments, numbers and dates, law and legal references, illustrations, notes and references, and bibliographies. The guidelines are complemented by the New Oxford Dictionary for Writers and Editors, which features 25,000 alphabetically arranged entries giving authoritative advice on those words and names which raise questions time and time again because of spelling, capitalization, hyphenation, or cultural and historical context. Entries give full coverage of recommended spellings, variant forms, confusable words, hyphenation, capitalization, foreign and specialist terms, proper names, and abbreviations. The dictionary a...

  15. Erotic(izing Cubans

    Directory of Open Access Journals (Sweden)

    Virginia R. Domínguez

    1996-07-01

    Full Text Available [First paragraph] Sugar's Secrets: Race and the Erotics of Cuban Nationalism. VERA M. KUTZINSKI. Charlottesville: University Press of Virginia, 1993. xvii + 287 pp. (Cloth US$ 40.00, Paper US$ 17.95 Life on the Hyphen: The Cuban-American Way. GUSTAVO PÉREZ FlRMAT. Austin: University of Texas Press, 1994. xii + 217 pp. (Cloth US$ 30.00, Paper US$ 12.95 When a country is subjected to as much external political and ideological scrutiny as Cuba in the post-Batista years, scholarly explorations of something other than its foreign policy, its political economy, and its human rights abuses provide a breath of fresh air. But I am struck by the other things Sugar's Secrets and Life on the Hyphen have in common and how suspicious I am of their commonalities.

  16. Gas Chromatography/Atmospheric Pressure Chemical Ionization-Fourier Transform Ion Cyclotron Resonance Mass Spectrometry of Pyrolysis Oil from German Brown Coal

    Directory of Open Access Journals (Sweden)

    Jan Zuber

    2016-01-01

    Full Text Available Pyrolysis oil from the slow pyrolysis of German brown coal from Schöningen, obtained at a temperature of 500°C, was separated and analyzed using hyphenation of gas chromatography with an atmospheric pressure chemical ionization source operated in negative ion mode and Fourier transform ion cyclotron resonance mass spectrometry (GC-APCI-FT-ICR-MS. Development of this ultrahigh-resolving analysis method is described, that is, optimization of specific GC and APCI parameters and performed data processing. The advantages of GC-APCI-FT-ICR-MS hyphenation, for example, soft ionization, ultrahigh-resolving detection, and most important isomer separation, were demonstrated for the sample liquid. For instance, it was possible to separate and identify nine different propylphenol, ethylmethylphenol, and trimethylphenol isomers. Furthermore, homologous series of different acids, for example, alkyl and alkylene carboxylic acids, were verified, as well as homologous series of alkyl phenols, alkyl dihydroxy benzenes, and alkoxy alkyl phenols.

  17. Development of LC/MS techniques for plant and drug metabolism studies

    OpenAIRE

    Petsalo, A. (Aleksanteri)

    2011-01-01

    Abstract Liquid chromatography (LC) combined with mass spectrometry (MS) is a powerful tool for qualitative and quantitative analytics of organic molecules from various matrices, and the use of this hyphenated technique is very common in bioanalytical laboratories. In this study, LC/MS methods and the required sample preparation applications were developed for plant flavonoid and drug metabolism studies. The main focus was in developing methods to be used during cytochrome P450 (CYP) -spe...

  18. Raman spectroscopy in pharmaceutical product design

    DEFF Research Database (Denmark)

    Paudel, Amrit; Raijada, Dhara; Rantanen, Jukka

    2015-01-01

    molecular-based drug discovery, design of innovative drug delivery systems and quality control of finished products. This review presents concise accounts of various conventional and emerging Raman instrumentations including associated hyphenated tools of pharmaceutical interest. Moreover, relevant...... application cases of Raman spectroscopy in early and late phase pharmaceutical development, process analysis and micro-structural analysis of drug delivery systems are introduced. Finally, potential areas of future advancement and application of Raman spectroscopic techniques are discussed....

  19. A neuron-in-capillary platform for facile collection and mass spectrometric characterization of a secreted neuropeptide

    OpenAIRE

    Chang Young Lee; Yi Fan; Rubakhin, Stanislav S.; Sook Yoon; Sweedler, Jonathan V.

    2016-01-01

    The integration of microfluidic devices—which efficiently handle small liquid volumes—with separations/mass spectrometry (MS) is an effective approach for profiling the neurochemistry occurring in selected neurons. Interfacing the microfluidic cell culture to the mass spectrometer is challenging because of geometric and scaling issues. Here we demonstrate the hyphenation of a neuron-in-capillary platform to a solid phase extraction device and off-line MS. A primary neuronal culture of Aplysia...

  20. The Contrasting Effects of Culture on Consumer Tolerance: Interpersonal Face and Impersonal Fate

    OpenAIRE

    Haksin Chan; Lisa C. Wan; Leo Y M Sin

    2009-01-01

    This research highlights two cultural tendencies—concern for face and belief in fate—that are characteristic of Asian (vs. Western) consumers. In three cross&hyphen;cultural studies on service failures, we show that these cultural tendencies have contrasting effects on consumer tolerance, such that Asian (vs. Western) consumers are more dissatisfied with social failures but less dissatisfied with nonsocial failures. We further demonstrate that these contrasting effects of culture are sensitiv...

  1. Selenium Metabolism in Cancer Cells: The Combined Application of XAS and XFM Techniques to the Problem of Selenium Speciation in Biological Systems

    OpenAIRE

    Harris, Hugh H; Stefan Vogt; Witting, Paul K.; Aitken, Jade B.; Lydia Finney; Weekley, Claire M.

    2013-01-01

    Determining the speciation of selenium in vivo is crucial to understanding the biological activity of this essential element, which is a popular dietary supplement due to its anti-cancer properties. Hyphenated techniques that combine separation and detection methods are traditionally and effectively used in selenium speciation analysis, but require extensive sample preparation that may affect speciation. Synchrotron-based X-ray absorption and fluorescence techniques offer an alternative appro...

  2. Basit horlayan ve tıkayıcı uyku apne sendromlu hastalardan toplanacak fizyolojik sinyallerin analizi ve karşılaştırılması

    OpenAIRE

    DEMİRGÜNEŞ, Doğan Deniz

    2009-01-01

  1. Size exclusion and anion exchange high performance liquid chromatography for characterizing metals bound to marine dissolved organic matter

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Otero, Natalia; Bermejo-Barrera, Pilar [Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, Avenida das Ciencias, s/n, 15782 Santiago de Compostela (Spain); Moreda-Pineiro, Antonio, E-mail: antonio.moreda@usc.es [Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, Avenida das Ciencias, s/n, 15782 Santiago de Compostela (Spain)

    2013-01-14

    Highlights: Black-Right-Pointing-Pointer Fractionation methods for assessing metals bound to marine DOM were developed. Black-Right-Pointing-Pointer SEC and AEC with UV detection and hyphenated with inductively coupled plasma-mass spectrometry were used. Black-Right-Pointing-Pointer SEC-UV showed marine DOM of molecular weights from 16 to 1 kDa. Black-Right-Pointing-Pointer Cobalt, manganese, strontium and zinc are bound to marine DOM. - Abstract: Size exclusion chromatography (SEC) followed by anion exchange chromatography (AEC) hyphenated with inductively coupled plasma-mass spectrometry (ICP-MS) was applied for fractionating metals bound to marine dissolved organic matter (DOM). Surface seawater samples (100 L) were subjected to tangential flow ultrafiltration (10,000 Da cut off) for isolating and pre-concentrating dissolved large molecules. The isolated fraction (retentate) consisted of 1 L, which was further freeze-dried and re-dissolved to 250 mL with ultrapure water. After HI Trap desalting of the re-dissolved retentate, SEC with UV detection showed marine DOM ranging from 6.5 kDa (lower than the permeable volume of the SEC column) to 16 kDa. A further characterization of this fraction by AEC with UV detection revealed the existence of four groups of macromolecules exhibiting retention times of 2.3, 2.8, 4.5 and 14.0 min. AEC hyphenated with ICP-MS showed the presence of strontium and zinc in the first AE fraction isolated from the SEC fraction; while manganese was found to be bound to the second AE fraction. Cobalt was found to be bound to molecules comprising the third AE fraction.

  2. Production of unusual dispiro metabolites in Pestalotiopsis virgatula endophyte cultures

    DEFF Research Database (Denmark)

    Kesting, Julie Regitze; Olsen, Lars; Stærk, Dan;

    2011-01-01

    . Analysis of the fermentation medium extract was performed using an HPLC-PDA-MS-SPE-NMR hyphenated system, which led to the identification of a total of eight metabolites (1-8), six of which are new. Most of the metabolites are structurally related and are derivatives of benzo[c]oxepin, rare among natural...... supported by time-dependent density-functional theory calculations (B3LYP/TZVP level). This work demonstrates that a largely complete structure elucidation of numerous metabolites present in a raw fermentation medium extract can be performed by the HPLC-SPE-NMR technique using only a small amount of the...

  3. Dichlorinated and Brominated Rugulovasines, Ergot Alkaloids Produced by Talaromyces wortmannii

    DEFF Research Database (Denmark)

    Soman De Medeiros, Lívia; da Silva, José Vinícius; Abreu, Lucas Magalhães;

    2015-01-01

    . Brominated rugulovasines were also detected when the microbial incubation medium was supplemented with bromine sources. Studies from 1D/2D NMR and HRMS spectroscopy data allowed the structural elucidation of the dichlorinated compounds, while tandem MS/HRMS data analysis supported the rationalization of......UHPLC-DAD-HRMS based dereplication guided the detection of new halogenated alkaloids co-produced by Talaromyces wortmannii. From the fungal growth in large scale, the epimers 2,8-dichlororugulovasines A and B were purified and further identified by means of a HPLC-SPE/NMR hyphenated system...

  4. Method optimization and quality assurance in speciation analysis using high performance liquid chromatography with detection by inductively coupled plasma mass spectrometry

    DEFF Research Database (Denmark)

    Larsen, Erik Huusfeldt

    1998-01-01

    operating characteristics of the entire hyphenated system. An isocratic HPLC system, which employs an aqueous mobile phase with organic buffer constituents, is well suited for introduction into the ICP-MS because of the stability of the detector response and high degree of analyte sensitivity attained...... speciation in the shrimp sample. With this analytical technique the HPLC retention time in combination with mass analysis of the molecular ions and their collision-induced fragments provide almost conclusive evidence of the identity of the analyte species. The speciation methods are validated by establishing...

  5. Caracterización antimicrobiana y fisico-quimica de muestras de propoleo proveniente de la región andina colombiana

    OpenAIRE

    Scoaris D O; Tello J; Figueroa J.; Bastos E.; Guzman D

    2011-01-01

    hyphenate: auto; text-autospace: ideograph-numeric;">El propóleo es un material resinoso, de origen animal, producido por las abejas a partir de diversos materiales vegetales. El objetivo de este trabajo fue caracterizar muestras de propoleo provenientes de la región  andina Colombiana respecto a su per...

  6. “I WANT TO BE NOTHING”. CHALLENGING NOTIONS OF CULTURE, RACE AND IDENTITY

    Directory of Open Access Journals (Sweden)

    Agata Lubowicka

    2011-01-01

    Full Text Available This article tackles the issue of “hyphenated identities” in Heidi W. Durrow’s novel The girl who fell from the sky (2010, whose main topic is growing up as a girl of mixed race in a dominant black culture. This article examines how Rachel Morse, the main character in the novel, challenges racism and the essentialist notion of identity. Firstly, Stuart Hall and Paul Gilroy’s approaches to that issue are introduced and discussed. Then in relation to their theories an interpretation of Durrow’s

  7. Occurrence, biological activities and 13C NMR data of amides from Piper (Piperaceae

    Directory of Open Access Journals (Sweden)

    Jeferson C. do Nascimento

    2012-01-01

    Full Text Available This manuscript describes an update review with up to 285 references concerning the occurrence of amides from a variety of species of the genus Piper (Piperaceae. Besides addressing occurrence, this review also describes the biological activities attributed to extracts and pure compounds, a compiled 13C NMR data set, the main correlations between structural and NMR spectroscopic data of these compounds, and employment of hyphened techniques such as LC-MS, GC-MS and NMR for analysis of amides from biological samples and crude Piper extracts.

  8. ISIDORE, a probe for in situ trace metal speciation based on Donnan membrane technique with related electrochemical detection part 1: Equilibrium measurements.

    Science.gov (United States)

    Parat, Corinne; Pinheiro, J P

    2015-10-01

    This work presents the development of a new probe (ISIDORE probe) based on the hyphenation of a Donnan Membrane Technique device (DMT) to a screen-printed electrode through a flow-cell to determine the free zinc, cadmium and lead ion concentration in natural samples, such as a freshwater river. The probe displays many advantages namely: (i) the detection can be performed on-site, which avoids all problems inherent to sampling, transport and storage; (ii) the low volume of the acceptor solution implies shorter equilibration times; (ii) the electrochemical detection system allows monitoring the free ion concentration in the acceptor solution without sampling. PMID:26481984

  9. Information meeting CETAMA; Journees d'information CETAMA

    Energy Technology Data Exchange (ETDEWEB)

    Moulin, C.; Denauwer, C.; Schlegel, M.; Moisy, P.; Gouget, B.; Carriere, M.; Baglan, N.; Reiller, P.; Hanssens, A.; Boullis, B.; Leguay, J.J.; Vercouter, T.; Guilbaud, P.; Taran, F.; Bion, L.; Chaix, P.; Madic, C.; Lecomte, M.; Moulin, C.; Lobinski, R.; Fourest, B.; Hagege, A.; Mercier, F.; Billard, I.; Denecke, M.; Neu, M.; Bernhard, G.; Duffield, J.; Gilbin, R.; Grenthe, I.; Hummel, W.; Turq, P.; Van Der Lee, J

    2004-07-01

    This seminar devoted to the speciation was presented in four main sessions: analytical speciation (actinides and lanthanides speciation, methodology developments, the XPS contribution of hyphenated CE-IPS/MS in metal/protein interaction, spectroscopy...), the applications to the biological and environmental systems (plutonium and neptunium speciation, uranium in plants, radionuclides speciation and interaction with living organisms...), the data bases (advances in chemical thermodynamic database, theoretical chemistry calculation, discovery of powerful uranyl ligands, simulation...) and projects bound to databases and analytical speciation ( BASSIST-GT32, Actinet network, EUROSPART, Gdr Paris, Common Thermodynamic Database Project, ToxNuc-E). (A.L.B.)

  10. Humic and fulvic acids in groundwater

    International Nuclear Information System (INIS)

    A non-ionic polymeric sorbent DAX-8 (XAD-8) was applied to the isolation of humic and fulvic acids from groundwater. This procedure was able to isolate approximately 40% of the DOC as humic solutes. For the investigation of the structure and molecular size distribution of the isolated humic solutes, the hyphenated SEC-ESI-MS system with a quadrupole mass spectrometer and SEC-UV and fluorescence detectors was utilized. For the higher-molecular-weight humic acids, the ESI-MS loses sensitivity compared with the parallel UV detection, because of the difficulty in getting the ionized humic compounds to fly efficiently through the mass spectrometer. (orig.)

  11. Molecular size distribution and structure investigations of humic substances in groundwater

    International Nuclear Information System (INIS)

    A non-ionic macroporous polymeric sorbent DAX-8 was applied to the isolation of humic and fulvic acids from groundwater. This procedure was able to isolate approximately 40% of the DOC as humic solutes. For the investigation of the structure and molecular size distribution of the isolated humic solutes, the hyphenated SEC-ESIMS system with a quadrupole mass spectrometer and a UV detector were utilized. For the higher-molecular-weight humic acids, the ESI-MS loses sensitivity compared with the parallel UV detection, because of the difficulty in getting the ionized humic compounds to fly efficiently through the mass spectrometer. (orig.)

  12. Correlations between dioxin-like and indicators PCBs: Potential consequences for environmental studies involving fish or sediment

    OpenAIRE

    Babut, M.; Miège, C.; Villeneuve, B.; Abarnou, A.; Duchemin, J.; Marchand, P.; Narbonne, J. F.

    2009-01-01

    Among the numerous PCB congeners, most of the dioxin-like PCBs (DL-PCBs) need to be characterized by hyphenated techniques. It has been shown in several instances that these congeners are well related to the total PCB content in fish. We examined datasets collected mainly in France, on freshwater and marine fish and sediments. A statistical model linking DL- and indicator PCBs was developed for a dataset composed of freshwater fishes, and proved to predict well DL-PCBs from indicator PCBs in ...

  13. Development of a simple extraction cell with bi-directional continuous flow coupled on-line to ICP-MS for assessment of elemental associations in solid samples

    DEFF Research Database (Denmark)

    Buanuam, Janya; Tiptanasup, Kasipa; Shiowatana, Juwadee;

    2006-01-01

    to discretely introduce appropriate extract volumes to the detector at a given time and with a given dilution factor. The proposed hyphenated method demonstrates excellent performance for on-line monitoring of major and trace elements (Ca, Mn, Fe, Ni, Pb, Zn and Cd) released when applying the various...... into the kinetics of the metal release are obtained. With the simultaneous multielement detection capability of ICP-MS, the dynamic fractionation system presents itself as an efficient front-end for evaluation of actual elemental association by interelement comparison of metals leached concurrently...... during the extraction time. Thus, the intimate elemental association between Cd and Zn in contaminated soils could be assessed....

  14. Historiography and Historicality

    OpenAIRE

    Garba, Ismail Bala

    2013-01-01

    Note portant sur l’auteur Ranajit Guha, History at the Limit of World-History, New York: Columbia University Press, 2002,128 pp. ISBN 0-231-12418-X, Hardback Ranajit Guha’s History at the Limit of World-History fuses, as it were, both practice and theory by conceptualising “world history” (without the hyphen) in such a way as to see it critically as a problem of whether it is possible to achieve any level of speciality in an enormous field of that name. What was once regarded as world history...

  15. Instrumental and methodological developments for isotope dilution analysis of gaseous mercury species

    OpenAIRE

    Larsson, Tom

    2007-01-01

    This thesis deals with instrumental and methodological developments for speciation analysis of gaseous mercury (Hg(g)), based on isotope dilution analysis (IDA). The studied species include Hg0, (CH3)2Hg, CH3HgX and HgX2 (where X symbolises a negatively charged counter ion in the form of a halide or hydroxyl ion). Gas chromatography hyphenated with inductively coupled plasma mass spectrometry (GC-ICPMS) was used for separation and detection of Hg(g) species. Permeation tubes were used for the...

  16. Grammatically Correct The Essential Guide to Spelling, Style, Usage, Grammar, and Punctuation

    CERN Document Server

    Stilman, Anne

    2010-01-01

    How does good writing stand out? If its purpose is to convey facts, findings, or instructions, it need be read only once for its content to be clear. If its purpose is to entertain or to provoke thought, it makes readers want to come back for more. Revised and updated, this guide covers four essential aspects of good writing:Individual words - spelling variations, hyphenation, frequently confused homonyms, frequently misused words and phrases, irregular plurals and negatives, and uses of capitalization and type style to add special meaningsPunctuation - the role of each mark in achieving clar

  17. Detekce dasatinibu pomocí předřazené reakce s mědí a hmotnostní detekcí

    Czech Academy of Sciences Publication Activity Database

    Jaklová Dytrtová, Jana; Jakl, M.; Navrátil, Tomáš

    Ústí nad Labem: Srsenová Lenka - Best Servis, 2015 - (Navrátil, T.; Fojta, M.; Schwarzová, K.), s. 76-79 ISBN 978-80-905221-3-8. [Moderní elektrochemické metody /35./. Jetřichovice (CZ), 18.05.2015-22.05.2015] R&D Projects: GA ČR GP13-21409P; GA ČR(CZ) GAP208/12/1645 Institutional support: RVO:61388963 ; RVO:61388955 Keywords : electrochemical separation * hyphenation * EC-ESI-MS * copper Subject RIV: CF - Physical ; Theoretical Chemistry

  18. Full quantification of selenium species by RP and AF-ICP-qMS with on-line isotope dilution in serum samples from mercury-exposed people supplemented with selenium-enriched yeast

    DEFF Research Database (Denmark)

    Li, Yu-Feng; Hu, Liang; Li, Bai;

    2011-01-01

    and affinity chromatography (AF) hyphenated to inductively coupled plasma-(quadrupole) mass spectrometry (ICP-qMS) with post-column isotope dilution analysis (IDA) and a collision cell technique (CCT). Different Se species like inorganic Se (Se4+ and Se6+), selenocystine (SeCys), selenomethionine (Se......Met), selenoprotein P (SelP), selenoalbumin (SeAlb) and glutathione peroxidase (GPx) can be separated and quantified. The proposed methodology was used to qualitatively and quantitatively study the dynamic distribution of Se species in human serum samples from the Hg-contaminated area after supplementation with 100...

  19. Methyl mercury in nail clippings in relation to fish consumption analysis with gas chromatography coupled to inductively coupled plasma mass spectrometry: a first orientation.

    Science.gov (United States)

    Krystek, Petra; Favaro, Paulo; Bode, Peter; Ritsema, Rob

    2012-08-15

    For the identification of human exposure to one of the most toxic compounds, which is methyl mercury (MeHg(+)), fingernail clippings were selected as the matrix of interest. Within this pilot study, six samples from different origins and from people with different food consumption patterns were chosen. Species-analysis of MeHg(+) was performed according to the following procedure: dissolution of the sample material in tetramethylammonium hydroxide (TMAH), derivatisation of MeHg(+) with sodium tetraethylborate (NaBEt(4)), extraction into iso-octane and measurement with gas chromatography hyphenated to inductively coupled plasma mass spectrometry (GC-ICPMS) for the quantification MeHg(+). PMID:22841050

  20. Occurrence, biological activities and {sup 13}C NMR data of amides from Piper (Piperaceae)

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Jeferson C. do; Paula, Vanderlucia F. de [Universidade Estadual do Sudoeste da Bahia, Jequie, BA (Brazil). Dept. de Quimica e Exatas; David, Jorge M. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica; David, Juceni P., E-mail: jmdavid@ufba.br [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Fac. de Farmacia

    2012-07-01

    This manuscript describes an update review with up to 285 references concerning the occurrence of amides from a variety of species of the genus Piper (Piperaceae). Besides addressing occurrence, this review also describes the biological activities attributed to extracts and pure compounds, a compiled {sup 13}C NMR data set, the main correlations between structural and NMR spectroscopic data of these compounds, and employment of hyphened techniques such as LC-MS, GC-MS and NMR for analysis of amides from biological samples and crude Piper extracts. (author)

  1. Development of high sensitivity capillary electrophoresis - mass spectrometry coupling : application to multi-level characterization of proteins

    OpenAIRE

    Gahoual, Rabah

    2014-01-01

    Interfacings allowing the hyphenation of capillary electrophoresis (CE) to ESI mass spectrometry(MS) currently suffer from lack of robustness and sensitivity. This work describes the application of a new design of CE-ESl-MS coupling referred as the CESl-MS. Characterization of the ESI generated through the CESl-MS system showed the production of a nanoESI allowing to increase drastically the sensitivity compared to conventional ESI. The CESl-MS was used as a nanoESI infusion platform allowing...

  2. A dupla face de Janus da China

    Directory of Open Access Journals (Sweden)

    Henrique Rattner

    2010-06-01

    Full Text Available Na mitologia romana, Janus é o rei mais antigo do Latium. Por ter acolhido a Saturno, expulso do Olimpo, este lhe brindou com uma visão em que tanto o futuro quanto o passado estivessem presentes, ficando assim conhecido como dono de duas faces. Essa duplicidade de personagem aplica-se perfeitamente ao papel da política chinesa, neste início de século XXI.

  3. Elemental ratios for characterization of quantum-dots populations in complex mixtures by asymmetrical flow field-flow fractionation on-line coupled to fluorescence and inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Highlights: • The hyphenated system allows unequivocal identification of nanoparticle populations. • AF4 separation permitted detection of unexpected nanosized species in a sample. • ICP-QQQ provides elemental ratios with adequate accuracy in every nanoparticle. • Purity and chemical composition of different quantum dot samples were assessed. - Abstract: Separation and identification of nanoparticles of different composition, with similar particle diameter, coexisting in heterogeneous suspensions of polymer-coated CdSe/ZnS quantum dots (QDs) have been thoroughly assessed by asymmetric flow field-flow fractionation (AF4) coupled on-line to fluorescence and inductively coupled plasma mass spectrometry (ICPMS) detectors. Chemical characterization of any previously on-line separated nanosized species was achieved by the measurement of the elemental molar ratios of every element involved in the synthesis of the QDs, using inorganic standards and external calibration by flow injection analysis (FIA). Such elemental molar ratios, strongly limited so far to pure single nanoparticles suspensions, have been achieved with adequate accuracy by coupling for the first time an ICP-QQQ instrument to an AF4 system. This hyphenation turned out to be instrumental to assess the chemical composition of the different populations of nanoparticles coexisting in the relatively complex mixtures, due to its capabilities to detect the hardly detectable elements involved in the synthesis. Interestingly such information, complementary to that obtained by fluorescence, was very valuable to detect and identify unexpected nanosized species, present at significant level, produced during QDs synthesis and hardly detectable by standard approaches

  4. Determination of cadmium and lead species and phytochelatins in pea (Pisum sativum) by HPLC-ICPMS and HPLC-ESIMSn

    International Nuclear Information System (INIS)

    Full text: Trace elements play an important role in the functioning of life on our planet. Some of them can be highly toxic, whereas others can be essential. These effects are very often related to particular form in which the element is present. Often these different chemical forms of a particular element or its compounds are referred to as 'species'. Cadmium and lead are widespread heavy metal pollutants released into the environment by human activities. The presence of Pb2+ and Cd2+ in the environment leads to a numerous disturbances in many metabolic processes in plants. Inhibition of growth is a major symptom. Hyphenated techniques, such as HPLC-ICPMS and HPLC-ESIMSn seem to be the best analytical instruments to study metal speciation in plants. In our study, we used hyphenated techniques to identify compounds engaged in Cd and Pb metabolism and to perform analysis of metal complexes induced in Pisum sativum exposed to cadmium and lead. These identified compounds might be valuable source of information to study metal accumulation mechanism for bioremediation processes. (author)

  5. Chiral speciation of selenoamino acids in biological samples.

    Science.gov (United States)

    Chen, Beibei; He, Man; Zhong, Cheng; Hu, Bin

    2014-10-10

    In this paper, the "state of the art" of chiral speciation of selenoamino acids (SeAAs) in biological samples is critically reviewed. The significance and the features of such studies are highlighted. A special focus lies on chiral speciation of SeAAs by hyphenation techniques in which a chiral separation method (such as gas chromatography (GC), high performance liquid chromatography (HPLC) and capillary electrophoresis (CE)) is on-line coupled with an elemental specific detector, especially inductively coupled plasma mass spectrometry (ICP-MS). The advances in the development and application of hyphenation techniques in chiral speciation of SeAAs in biological samples are summarized and a perspective for future developments including sophisticated and innovative applications is discussed. Overall, HPLC-ICP-MS is more applicable than GC/CE-ICP-MS for chiral speciation of SeAAs. In the future, more novel chiral HPLC methods with high enantio-resolution, low cost and robustness, and their more applications in real biological samples analysis are expected. PMID:25130085

  6. Speciation of human serum proteins based on trace metal mapping analysis by CIM monolithic disk column HPLC/ICP-MS in complement with off-line MALDI-TOF-MS analysis

    International Nuclear Information System (INIS)

    A multiply hyphenated HPLC/UV/ICP-MS system equipped with a fraction collection valve for subsequent MALDI-TOF-MS analysis was constructed, and its applicability to the speciation of metalloproteins in human serum was evaluated. A weak anion-exchange CIM monolithic disk column was employed for protein separation, in which gradient elution of proteins with volatile salts was carried out while taking into account the compatibility with ICP-MS instrument. As a result of optimization, representative serum proteins, such as γ-globulin (γGb), albumin (Ab), ceruloplasmin (Cp), transferrin (Tf), and α2-macroglobulin (α2Mgb), were separated on the disk column with a linear concentration gradient of CH3COONH4 in 20 mM Tris-HCl buffer (pH 7.4). These proteins, which were primarily assigned by UV absorption at 280 nm, were clearly identified with on-line multielement detection using ICP-MS as well as with off-line MALDI-TOF-MS analysis of each successive fraction collected. It was concluded that the present multiply hyphenated system will be useful for identifying proteins in biological samples. (author)

  7. NRC [Nuclear Regulatory Commission] editorial style guide

    International Nuclear Information System (INIS)

    Editorial style refers to the choices that writers, editors, and secretaries make to eliminate inconsistencies in their documents. These choices apply to the recurrent features of a document such as abbreviations, capitalization, compound words, numbers, symbols, and punctuation, as well as to references and footnotes. Making these choices is sometimes difficult because usage changes as the language evolves. Consider the use of hyphens, for example. Do we write non-power reactor or nonpower reactor? Is it on-site incident or onsite incident? Although usage is moving away from the use of hyphens with prefixes, the authorities who compile style guides do not always agree about which choice to use at a given time. Moreover, each discipline -- law, physics, mathematics -- has specific standards that apply to the publications for that discipline. Even in an area as seemingly certain as spelling, overlapping usage exists. Reputable dictionaries show both ''align'' and ''aline'' as correct spellings. Likewise, ''disc, disk, and diskette'' currently coexist as equally valid choices

  8. Elemental ratios for characterization of quantum-dots populations in complex mixtures by asymmetrical flow field-flow fractionation on-line coupled to fluorescence and inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Menendez-Miranda, Mario; Fernandez-Arguelles, Maria T.; Costa-Fernandez, Jose M., E-mail: jcostafe@uniovi.es; Encinar, Jorge Ruiz; Sanz-Medel, Alfredo, E-mail: asm@uniovi.es

    2014-08-11

    Highlights: • The hyphenated system allows unequivocal identification of nanoparticle populations. • AF4 separation permitted detection of unexpected nanosized species in a sample. • ICP-QQQ provides elemental ratios with adequate accuracy in every nanoparticle. • Purity and chemical composition of different quantum dot samples were assessed. - Abstract: Separation and identification of nanoparticles of different composition, with similar particle diameter, coexisting in heterogeneous suspensions of polymer-coated CdSe/ZnS quantum dots (QDs) have been thoroughly assessed by asymmetric flow field-flow fractionation (AF4) coupled on-line to fluorescence and inductively coupled plasma mass spectrometry (ICPMS) detectors. Chemical characterization of any previously on-line separated nanosized species was achieved by the measurement of the elemental molar ratios of every element involved in the synthesis of the QDs, using inorganic standards and external calibration by flow injection analysis (FIA). Such elemental molar ratios, strongly limited so far to pure single nanoparticles suspensions, have been achieved with adequate accuracy by coupling for the first time an ICP-QQQ instrument to an AF4 system. This hyphenation turned out to be instrumental to assess the chemical composition of the different populations of nanoparticles coexisting in the relatively complex mixtures, due to its capabilities to detect the hardly detectable elements involved in the synthesis. Interestingly such information, complementary to that obtained by fluorescence, was very valuable to detect and identify unexpected nanosized species, present at significant level, produced during QDs synthesis and hardly detectable by standard approaches.

  9. Horseradish peroxidase and antibody labeled gold nanoparticle probe for amplified immunoassay of ciguatoxin in fish samples based on capillary electrophoresis with electrochemical detection.

    Science.gov (United States)

    Zhang, Zhaoxiang; Liu, Ying; Zhang, Chaoying; Luan, Wenxiu

    2015-03-01

    This paper describes a new amplified immunoassay with horseradish peroxidase (HRP) and antibody (Ab) labeled gold nanoparticles (AuNPs) probe hyphenated to capillary electrophoresis (CE) with electrochemical (EC) detection for ultrasensitive determination of ciguatoxin CTX1B. AuNPs were conjugated with HRP and Ab, and then incubated with limited amount of CTX1B to produce immunocomplex. The immunoreactive sample was injected into capillary for CE separation and EC detection. Enhanced sensitivity was obtained by adopting the AuNPs as carriers of HRP and Ab at high HRP/Ab molar ratio. The calibration curve of CTX1B was in the range of 0.06-90 ng/mL. The detection limit was 0.045 ng/mL, which is 38-fold lower than that of HPLC-MS method for CTX1B analysis. The proposed method was successfully applied for the quantification of CTX1B in contamined fish samples by simultaneously labeling Ab and HRP on AuNPs. The amplified IA with HRP and Ab labeled AuNPs probe hyphenated to CE and EC detection provides a sensitive analytical approach for the determination of trace ciguatoxin in complex samples. PMID:25637767

  10. Analysis of pharmaceutical impurities using multi-heartcutting 2D LC coupled with UV-charged aerosol MS detection.

    Science.gov (United States)

    Zhang, Kelly; Li, Yi; Tsang, Midco; Chetwyn, Nik P

    2013-09-01

    To overcome challenges in HPLC impurity analysis of pharmaceuticals, we developed an automated online multi-heartcutting 2D HPLC system with hyphenated UV-charged aerosol MS detection. The first dimension has a primary column and the second dimension has six orthogonal columns to enhance flexibility and selectivity. The two dimensions were interfaced by a pair of switching valves equipped with six trapping loops that allow multi-heartcutting of peaks of interest in the first dimension and also allow "peak parking." The hyphenated UV-charged aerosol MS detection provides comprehensive detection for compounds with and without UV chromophores, organics, and inorganics. It also provides structural information for impurity identification. A hidden degradation product that co-eluted with the drug main peak was revealed by RP × RP separation and thus enabled the stability-indicating method development. A poorly retained polar component with no UV chromophores was analyzed by RP × hydrophilic interaction liquid chromatography separation with charged aerosol detection. Furthermore, using this system, the structures of low-level impurities separated by a method using nonvolatile phosphate buffer were identified and tracked by MS in the second dimension. PMID:23821312

  11. [Analysis of irregularities in writing English and Serbian professional papers].

    Science.gov (United States)

    Kernican, Leotina; Mićić, Sofija

    2008-01-01

    There are many peculiarities and indecisions in the English and Serbian language. One of the crucial is doubtless a translation from Serbian into English. On the other hand, by analysing professional papers of English native speakers, a tendency of greater conciseness is shown. Thus a better knowledge of etymological structure and modern formal style in both languages is essential. Accordingly, it is of utmost importance to pay a special attention to appropriate collocations, text summarizing and various possible mistakes ranging from wrong spelling and improper use of some abbreviations of conventional titles to incorrect capitalization, hyphenated words, etc. Language is certainly a vivid unique style of each personality, even in professional formal writing, but, by using it, we naturally enrich the expression and quality of the language as a whole. PMID:18720760

  12. Analytical developments for screening of lanthanides/ligands interactions

    International Nuclear Information System (INIS)

    This work investigates the potential of hyphenated capillary electrophoresis and inductively coupled mass spectrometry to classify different ligands according to their europium binding affinity in a hydro-organic medium. On the one hand, this method enables to evaluate the affinity of phosphorus-containing ligands in less than two hours and using less than 15 ng of ligand. On the other hand, complexation constants could be determined. The results are in excellent agreement with the values obtained by spectrophotometric titrations.Moreover, a library of copolymers for solid/liquid extraction of europium is investigated. The extraction protocol enables to classify copolymers according to their europium affinity in a hydro-organic medium. This screening requires 60 mg of copolymers. For the most promising recognition properties and selectivity La3+/Eu3+/Lu3+ are evaluated. (author)

  13. Automotive Painting Technology A Monozukuri-Hitozukuri Perspective

    CERN Document Server

    Salazar, Abraham; Saito, Kozo

    2013-01-01

    This book offers unique and valuable contributions to the field. It offers breadth and inclusiveness. Most existing works on automotive painting cover only a single aspect of this complex topic, such as the chemistry of paint or paint booth technology. Monozukuri and Hitozukuri are Japanese terms that can be translated as “making things” and “developing people” but their implications in Japanese are richer and more complex than this minimal translation would indicate. The Monozukuri-Hitozukuri perspective is drawn from essential principles on which the Toyota approach to problem-solving and continuous improvement is based. From this perspective, neither painting technology R&D nor painting technology use in manufacturing can be done successfully without integrating technological and human concerns involved with making and learning in the broadest sense, as the hyphen is meant to indicate. The editors provide case studies and examples -- drawn from Mr. Toda’s 33 years of experience with automotiv...

  14. Determination of Kinetic Parameters within a Single Nonisothermal On-Flow Experiment by Nanoliter NMR Spectroscopy.

    Science.gov (United States)

    Gomez, M Victoria; Rodriguez, Antonio M; de la Hoz, Antonio; Jimenez-Marquez, Francisco; Fratila, Raluca M; Barneveld, Peter A; Velders, Aldrik H

    2015-10-20

    Conventional methods to determine the kinetic parameters for a certain reaction require multiple, separate isothermal experiments, resulting in time- and material-consuming processes. Here, an approach to determine the kinetic information within a single nonisothermal on-flow experiment is presented, consuming less than 10 μmol of reagents and having a total measuring time of typically 10 min. This approach makes use of a microfluidic NMR chip hyphenated to a continuous-flow microreactor and is based on the capabilities of the NMR chip to analyze subnanomole quantities of material in the 25 nL detection volume. Importantly, useful data are acquired from the microreactor platform in specific isothermal and nonisothermal frames. A model fitting the experimental data enables rapid determination of kinetic parameters, as demonstrated for a library of isoxazole and pyrazole derivatives. PMID:26383715

  15. Rapid prototyping of microfluidic chips for dead-volume-free MS coupling.

    Science.gov (United States)

    Dietze, Claudia; Scholl, Tobias; Ohla, Stefan; Appun, Johannes; Schneider, Christoph; Belder, Detlev

    2015-11-01

    A fast and straightforward method to prototype microfluidic chip systems for dead-volume-free hyphenation to electrospray-ionisation mass spectrometry is presented. The developed approach based on liquid-phase lithography provides an inexpensive and reliable access to microfluidic chips for MS coupling which can be manufactured in any laboratory with low technical demands. The rapid prototyping approach enables the seamless integration of capillaries serving as electrospray emitters with negligible dead volume. The high versatility of the presented prototyping method and the applicability of a variety of chip-based devices in different fields of lab-on-a-chip technology are established for analytical separations by means of chip-electrochromatography-MS and for continuous-flow synthesis using microreactor technology with MS detection. PMID:26391402

  16. The role of visual acuity and segmentation cues in compound word identification

    Directory of Open Access Journals (Sweden)

    Jukka eHyönä

    2012-06-01

    Full Text Available Studies are reviewed that demonstrate how the foveal area of the eye constrains how compound words are identified during reading. When compound words are short, their letters can be identified during a single fixation, leading to the whole-word route dominating word recognition from early on. Hence, visually marking morpheme boundaries by hyphens slows down processing by encouraging morphological decomposition when holistic processing is a feasible option. In contrast, the decomposition route dominates the early stages of identifying long compound words. Thus, visual marking of morpheme boundaries facilitates processing of long compound words, unless the initial fixation made on the word lands very close to the morpheme boundary. The reviewed pattern of results is explained by the visual acuity principle (Bertram & Hyönä, 2003 and the dual-route framework of morphological processing.

  17. Compound coverage enhancement of electrospray ionization mass spectrometry through the addition of a homemade needle.

    Science.gov (United States)

    Xiao, Shun; Qian, Shuai; Wang, Yi; Zhang, Yufeng; Cheng, Yiyu

    2013-03-21

    The response of many previously low-detectable or undetectable compounds in electrospray ionization mass spectrometry (ESI-MS) has been enhanced by the addition of a simple, homemade needle into the traditional ESI interface. The needle located between the ESI emitter and the ion sweep cone (inlet of the detector) would ionize those neutral gaseous compounds, formed during electrospray, by a corona discharge process. The mobile phases, ESI parameters and positions of the needle were investigated and optimized. Several groups of compounds and herbal extracts were tested using the homemade set-up. Both the results of the flow injection and the hyphenated MS analyses showed significant enhancement effects of our homemade needle. The advantages of the proposed method include low cost, simplicity and practicality. PMID:23364279

  18. Ionophores in the Environment

    DEFF Research Database (Denmark)

    Bak, Søren Alex; Hansen, Martin; Björklund, Erland;

    ) and antiparacitics (i.e. ionophores) posses an environmental effects of similar level as their parent compounds on i.e. the soil bacterial community (Halling-Sørensen et al.2002; Hansen et al. 2009). Ionophores are used extensively worldwide as prophylactic chemotherapeutics and growth promoters in livestock...... production. Ionophores are antibiotic drugs that form lipid soluble complexes with, primarily, alkali cations that inhibit or kill pathogenic parasites in livestock. Several reports have revealed that ionophores are emerging environmental contaminants in agricultural run-off waters, surface waters, sediments......, and ground waters, due to their continuously increased and constant application as feed additives in modern livestock production. This presentation will focus on the development of new analytical method for determination of ionophores in liquid and solid matrices. The hyphenated method consist of pressurised...

  19. Lignin profiling in extracted xylans by size-exclusion chromatography.

    Science.gov (United States)

    Hutterer, Christian; Schild, Gabriele; Kliba, Gerhard; Potthast, Antje

    2016-10-20

    Utilization of the polymeric parts of lignocellulose is expected to gain increasing importance in future biorefinery scenarios. In that respect, a particular focus is placed on hemicelluloses from different wood species gained from an industrially feasible upgrading step in the production of dissolving pulps from paper pulps. During alkaline post-extractions for hemicellulose removal, residual lignins are extracted as well. They are either covalently linked to the extracted hardwood xylans or simply co-dissolved in the alkaline lye. In order to better describe the lignin in xylan containing lyes, a method for lignin profiling was set up by hyphenating size-exclusion chromatography of xylans with UV detection which facilitates visualization of the residual lignin distribution. Simultaneous lignin quantification was achieved with lignin standards prepared from Kraft cooking liquors. The setup presented may serve as advanced characterization for novel xylan products. PMID:27474629

  20. Development of a micro flow-through cell for high field NMR spectroscopy.

    Energy Technology Data Exchange (ETDEWEB)

    Alam, Todd Michael; McIntyre, Sarah K.

    2011-05-01

    A highly transportable micro flow-through detection cell for nuclear magnetic resonance (NMR) spectroscopy has been designed, fabricated and tested. This flow-through cell allows for the direct coupling between liquid chromatography (LC) and gel permeation chromatography (GPC) resulting in the possibility of hyphenated LC-NMR and GPC-NMR. The advantage of the present flow cell design is that it is independent and unconnected to the detection probe electronics, is compatible with existing commercial high resolution NMR probes, and as such can be easily implemented at any NMR facility. Two different volumes were fabricated corresponding to between {approx}3.8 and 10 {micro}L detection volume. Examples of the performance of the cell on different NMR instruments, and using different NMR detection probes were demonstrated.

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

    DEFF Research Database (Denmark)

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

    2015-01-01

    /α-glucosidase/radical scavenging high-resolution inhibition profile - allowing proof of concept with Radix Scutellariae crude extract as a polypharmacological herbal drug. The triple bioactivity high-resolution profiles were used to pinpoint bioactive compounds, and subsequent structure elucidation was performed with hyphenated...... high-performance liquid chromatography – high-resolution mass spectrometry – solid-phase extraction – nuclear magnetic resonance spectroscopy. The only α-glucosidase inhibitor was baicalein, whereas main aldose reductase inhibitors in the crude extract were baicalein and skullcapflavone II, and main......In this work, development of a new microplate-based high-resolution profiling assay using recombinant human aldose reductase is presented. Used together with high-resolution radical scavenging and high-resolution α-glucosidase assays, it provided the first report of a triple aldose reductase...

  2. A review on the Standardization of herbal medicines

    Directory of Open Access Journals (Sweden)

    Dr Rajesh Kumari

    2016-02-01

    Full Text Available The world is witnessing an unprecedented growth in the usage of herbal products. India is a mother hub for natural herbs based science. Herbal drug technology is used for converting botanical materials into medicines, where standardization and quality control with proper integration of modern scientific techniques and traditional knowledge is important. For global harmonization WHO specific guidelines for the assessment of the safety, efficacy and quality of herbal medicines are of utmost importance. Standardization of drug means confirmation of its identity, quality and purity throughout all phases of its cycle. An overview covering the different techniques involved in standardization of crude/ finished compound drugs so far, e.g. macroscopic methods, microscopic methods, physical methods, chemical methods, biological methods.The chromatographic methods and comprehensive methods, such as fingerprint and multi- omponent quantification; hyphenated techniques, like HPLC-MS, GC-MS. and bhasma’s standardization are also discussed.

  3. Organometallic species of the elements tin, mercury and lead in sediments of the longitudinal profile of the River Elbe

    Energy Technology Data Exchange (ETDEWEB)

    Jantzen, E. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Physikalische und Chemische Analytik; Prange, A. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Physikalische und Chemische Analytik

    1995-12-31

    In 1992, for the first time, a whole longitudinal sediment profile of the River Elbe from the Czech Republic to the North Sea has been sampled within the framework of the project `Registration and assessment of harmful substances in the River Elbe: Heavy metals and heavy metal species`. Organometallic species of the elements tin, mercury and lead have been determined. The species have been extracted together from the wet sediments using hexane after an in-situ ethylation with sodium tetraethyl-borate (NaBEt{sub 4}). Gas chromatography-inductively coupled plasma-mass spectrometry (GC-ICP-MS), a very sensitive hyphenated technique for multielemental speciation analysis, has been used for their separation and detection. (orig.)

  4. Organometallic species of the elements tin, mercury and lead in sediments of the longitudinal profile of the river Elbe

    Energy Technology Data Exchange (ETDEWEB)

    Jantzen, E. [GKSS-Forschungszentrum Geesthacht GmbH, Institut fuer Physikalische und Chemische Analytik (Germany); Prange, A. [GKSS-Forschungszentrum Geesthacht GmbH, Institut fuer Physikalische und Chemische Analytik (Germany)

    1995-09-01

    In 1992, for the first time, a whole longitudinal sediment profile of the River Elbe from the Czech Republic to the North Sea has been sampled within the framework of the project ``Registration and assessment of harmful substances in the River Elbe: Heavy metals and heavy metal species``. Organometallic species of the elements tin, mercury and lead have been determined. The species have been extracted together from the wet sediments using hexane after an in-situ ethylation with sodium tetraethylborate (NaBEt{sub 4}). Gas chromatography-inductively coupled plasma-mass spectrometry (GC-ICP-MS), a very sensitive hyphenated technique for multielemental speciation analysis, has been used for their separation and detection. (orig.)

  5. LC-MS metabolomics from study design to data-analysis – using a versatile pathogen as a test case

    Directory of Open Access Journals (Sweden)

    Maya Berg

    2013-01-01

    Full Text Available Thanks to significant improvements in LC-MS technology, metabolomics is increasingly used as a tool to discriminate the responses of organisms to various stimuli or drugs. In this minireview we discuss all aspects of the LC-MS metabolomics pipeline, using a complex and versatile model organism, Leishmania donovani, as an illustrative example. The benefits of a hyphenated mass spectrometry platform and a detailed overview of the entire experimental pipeline from sampling, sample storage and sample list set-up to LC-MS measurements and the generation of meaningful results with state-of-the-art data-analysis software will be thoroughly discussed. Finally, we also highlight important pitfalls in the processing of LC-MS data and comment on the benefits of implementing metabolomics in a systems biology approach.

  6. Size-based characterization of nanoparticle mixtures by the inline coupling of capillary electrophoresis to Taylor dispersion analysis.

    Science.gov (United States)

    Oukacine, Farid; Morel, Aurélie; Desvignes, Isabelle; Cottet, Hervé

    2015-12-24

    Separation of closely related nanoparticles is still a challenging issue for the characterization of complex mixtures for industrial/research applications or regulatory purposes. In this work, the remarkable separating performances of CE were complemented with the absolute size-based determination provided by Taylor dispersion analysis (TDA) for the characterization of nanoparticle mixtures. The inline hyphenation of CE to TDA was successfully implemented for the baseline separation followed by a size-based characterization of a bimodal mixture containing two closely size-related nanolatexes (70nm and 56nm radii). A pixel sensor UV area imager providing three detection points along the capillary was used for a differential measurement of the peak broadening during the Taylor dispersion step. Comparison of this new technique with dynamic light scattering and hydrodynamic chromatography is also discussed. PMID:26653841

  7. Recent applications of liquid chromatography-mass spectrometry in natural products bioanalysis.

    Science.gov (United States)

    Xing, Jie; Xie, Chunfeng; Lou, Hongxiang

    2007-06-28

    Natural flavonoids, alkaloids, saponins and sesquiterpenoids have been extensively investigated because of their biological and physiological significances, as well as their promising clinical uses. It is necessary to monitor them or their metabolites in biological fluids for both pre-clinical studies and routine clinical uses. The successful hyphenation of LC and MS, which was thought as "the bird wants to marry with fish", has been conducted widely in biological samples analysis. This present paper reviewed the feasibility of LC-MS techniques in the identification and quantification of natural products (flavonoids, alkaloids, saponins and sesquiterpenoids) in biological fluids, dealing with sample preparation, LC techniques, suitability of different MS techniques. Perspective of LC-MS was also discussed to show the potential of this technology. The citations cover the period 2002-2006. We conclude that LC-MS is an extremely powerful tool for the analysis of natural products in biological samples. PMID:17317073

  8. First operation of the Bern AMS MICADAS

    International Nuclear Information System (INIS)

    The University of Bern has a long history of experience in precise 14C measurements based on the conventional counting laboratory founded more than 50 years ago. Due to the demanding preparation and measurement procedures, the throughput and required carbon mass of this technique both are the limiting factors. Therefore, the University of Bern decided to update the facility aiming at a new 14C laboratory equipped with an accelerator mass spectrometer (AMS) MICADAS. The focus of this laboratory is twofold. On the one hand, the access to routine 14C analysis for climate research and other disciplines will be improved on site. On the other hand, new hyphenated analytical systems shall be developed for online separation and 14C detection of specific fractions or individual compounds. The MICADAS became operational in November 2012. In this work, instruments, laboratory equipment, measures of quality assurance and first results are presented.

  9. Secoiridoids in olive seed: characterization of nuzhenide and 11-methyl oleosides by liquid chromatography with diode array and mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Silva, S.; Gomes, L.; Leitao, F.; Bronze, M.; Coelho, A. V.; Vilas Boas, L.

    2010-07-01

    The seed extracts of olive tree cultivars were analyzed by reverse phase HPLC with diode array detection and mass spectrometry. HPLC hyphenation with mass spectrometry (Ei source) in both polarity modes enabled the identification in olive seeds of nuzhenide and nuzhenide 11-methyl oleoside, among other 11-methyl oleosides, by means of MSn. The methods used allowed us to obtain olive seed profiles of phenolic components and to conclude that they are mainly secoiridoids. The quantification of detected phenolic secoiridoids was also achieved using ultraviolet detection ({lambda}= 240 nm) which enabled comparison of the samples. Nuzhenide and nuzhenide 11-methyl oleoside were the major components detected in olive seeds of all the cultivars studied, but variations in individual components of olive seeds were verified among the cultivars. The results also support the existence of di and tri(11-methyl oleosides) of nuzhenide. (Author)

  10. Methods for analysis of the distribution and speciation of iron and zinc in the cereal grain

    DEFF Research Database (Denmark)

    Hansen, Thomas Hesselhøj

    identification of P and S with mineral micronutrients can therefore be a circumstantial evidence for their chemical speciation. The focus of this PhD has therefore been on the analysis of mineral micronutrients as well as S and P. In this PhD, four methods for elemental analysis of the cereal grain have been...... novel high-throughput micro digestion method was developed, enabling the analysis of total element concentrations in small tissue fractions, such as the embryo of cereal grains. The method is based on small closed bombs that are microwaved and was validated for sample amounts between 1-20 mg using...... certified reference materials. This enabled high-throughput analysis of different grain tissue fractions and the variability in between them.. Moreover two methods for quantitative hyphenated ICP-MS analysis were developed. One enabled quantification of species in a chromatographic separation and the other...

  11. Targeted natural product isolation guided by HPLC-SPE-NMR: Constituents of Hubertia species

    DEFF Research Database (Denmark)

    Sprogoe, K.; Staek, D.; Jager, A.K.;

    2007-01-01

    The hyphenated technique, high-performance liquid chromatography-solid-phase extraction-nuclear magnetic resonance spectroscopy (HPLC-SPE-NMR), has been applied for rapid identification of novel natural products in crude extracts of Hubertia ambavilla and Hubertia tomentosa. The technique allowed....... Using homo- and heteronuclear 2D NMR data acquired in the HPLC-SPE-NMR mode, complete structure determination of three new natural products, i.e., 3,5-di-O-caffeoyl-4-O-[(1-hydroxy-4-oxocyclohexa-2,5-dienyl)acetyl]quini c acid (1), its 2-hydroxy derivative (2), and 3,5-di-O-caffeoyl-4-O-[(4......-hydroxyphenyl)acetyl]quinic acid (3), was performed. Finally, targeted isolation of 1 was achieved by SPE fractionation and preparative HPLC, followed by evaluation of its antioxidant and antimicrobial activity. In contrast to chlorogenic acid and 3,5-di-O-caffeoylquinic acid, which act as antioxidants...

  12. Combining asymmetrical flow field-flow fractionation with light-scattering and inductively coupled plasma mass spectrometric detection for characterization of nanoclay used in biopolymer nanocomposites

    DEFF Research Database (Denmark)

    Schmidt, Bjørn; Petersen, Jens Højslev; Koch, C. Bender;

    2009-01-01

    It is expected that biopolymers obtained from renewable resources will in due course become fully competitive with fossil fuel-derived plastics as food-packaging materials. In this context, biopolymer nanocomposites are a field of emerging interest since such materials can exhibit improved...... mechanical and barrier properties and be more suitable for a wider range of food-packaging applications. Natural or synthetic clay nanofillers are being investigated for this purpose in a project called NanoPack funded by the Danish Strategic Research Council. In order to detect and characterize the size of...... polylactide (PLA) with 5% Cloisite®30B (a derivatized montmorillonite clay) as a filler. Based on AF4-MALS analyses, we found that particles ranging from 50 to 800 nm in radius indeed migrated into the 95% ethanol used as a food simulant. The full hyphenated AF4-MALS-ICP-MS system showed, however, that none...

  13. Chlorococcalean microalgae Ankistrodesmus convolutes biodiesel characterization with Fourier transform-infrared spectroscopy and gas chromatography mass spectroscopy techniques

    Directory of Open Access Journals (Sweden)

    Swati SONAWANE

    2015-12-01

    Full Text Available The Chlorococcalean microalgae Ankistrodesmus convolutes was found in fresh water Godawari reservoir, Ahmednagar district of Maharashtra State, India. Microalgae are modern biomass for the production of liquid biofuel due to its high solar cultivation efficiency. The collection, harvesting and drying processes were play vital role in converting algal biomass into energy liquid fuel. The oil extraction was the important step for the biodiesel synthesis. The fatty acid methyl ester (FAME synthesis was carried through base catalyzed transesterification method. The product was analyzed by using the hyphened techniques like Fourier Transform-Infrared spectroscopy (FT-IR and Gas Chromatography Mass Spectroscopy (GCMS. FT-IR Spectroscopy was results the ester as functional group of obtained product while the Gas Chromatography Mass Spectroscopy was results the six type of fatty acid methyl ester with different concentration. Ankistrodesmus convolutes biodiesel consist of 46.5% saturated and 49.14% unsaturated FAME.

  14. Recitindu-l pe Norman Manea: Harta imaginară de-a lungul întregii opere

    OpenAIRE

    Brînduşa Nicolaescu

    2014-01-01

    Marcat de nostalgia pentru „România spiritului”, imagine reflectată şi de metafora „casa melcului”, fragmentele literare pe care le abordăm în această lucrare tratează o acută conştiinţă obsesivă a trans-localizării, care depăşeşte în importanţă conceptul ambiguu de ’hyphenated identity’ / „identitate hibridă” (evreu-român-american). Încercăm să urmărim traiectoriile narative/istorice pe harta imaginară a scrierilor lui Norman Manea, având în vedere concepte precum „geografie literară”, „imag...

  15. Recent trends in analytical methods and separation techniques for drugs of abuse in hair.

    Science.gov (United States)

    Baciu, T; Borrull, F; Aguilar, C; Calull, M

    2015-01-26

    Hair analysis of drugs of abuse has been a subject of growing interest from a clinical, social and forensic perspective for years because of the broad time detection window after intake in comparison to urine and blood analysis. Over the last few years, hair analysis has gained increasing attention and recognition for the retrospective investigation of drug abuse in a wide variety of contexts, shown by the large number of applications developed. This review aims to provide an overview of the state of the art and the latest trends used in the literature from 2005 to the present in the analysis of drugs of abuse in hair, with a special focus on separation analytical techniques and their hyphenation with mass spectrometry detection. The most recently introduced sample preparation techniques are also addressed in this paper. The main strengths and weaknesses of all of these approaches are critically discussed by means of relevant applications. PMID:25542354

  16. Study on Retention in Liquid Chromatography%关于液相色谱保留的研究

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    After joining the faculty at Toyohashi University of Technology (TUT) in 1978, the author has found two areas in separation sciences where microcolumn liquid chromatography (micro-LC) can be beneficial. One is the hyphenated techniques between many spectroscopic methods such as mass (MS), infrared (FT-IR) and atomic emission (ICP), and micro-LC. The other one is rather difficult, but basic and theoretical approach which deals with retention mechanism in LC. The latter project has especially been giving him a lot of scientific funs and honors in the last 20 years. On the occasion of being awarded by The Society for Chromatographic Sciences the author would like to summarize his contributions to this topic which asks us "What Is Chromatographic Retention".

  17. Prosecuting the Leaders: Promises, Politics and Practicalities

    Directory of Open Access Journals (Sweden)

    Robert Cryer

    2009-02-01

    Full Text Available Given recent developments in relation to the prosecution of international crimes,  it might be thought that one of the last bastions of sovereignty has been breached, and international criminal law has not only entrenched itself in international law. Indeed further to this, it has assumed a supranational position that stands entirely above States, promising justice for all and as a trump card over depredations committed in the name of State sovereignty. After all, Charles Taylor from Liberia is standing trial before the Special Court for Sierra Leone, Slobodan Milošević only escaped judgment by the International Criminal Tribunal for the former

  18. Novel applications of high performance ion chromatography-inductively coupled plasma mass spectrometry (HPIC-ICP-MS)

    CERN Document Server

    Hann, S

    2001-01-01

    This work demonstrates the development of highly sensitive and selective analytical methods, which make use of the hyphenation of high performance ion chromatography (HPIC) to inductively coupled plasma sector field mass spectrometry (ICP-SFMS). On-line coupling a chromatographic separation method with an elemental detection method provides two advantages: (1) the components of a possibly interfering matrix can be separated allowing accurate and precise ultra trace analysis of the element of interest and (2) elemental species of an element can be separated and quantified. In this work, matrix separation methods for interference free determination of 232Th, 234U, 235U and 238U in geological matrices were developed and employed. Furthermore HPIC-ICP-SFMS was applied for ultra trace analysis of Pd in environmental and geological matrices. The usefulness of HPIC-ICP-SFMS for speciation studies was demonstrated by investigating the interaction of an anti-cancer drug (cisplatin) with guanosine monophosphates.

  19. Developments and trends in inductively coupled plasma mass spectrometry and its influence on the recent advances in trace element analysis

    International Nuclear Information System (INIS)

    A brief introduction to the various instrumental methods such as atomic absorption spectrometry, x-ray fluorescence spectrometry, neutron activation analysis, inductively coupled plasma atomic emission spectrometry, thermal ionization mass spectrometry, etc. are presented highlighting their relative merits and demerits. The history and developments of inductively coupled plasma mass spectrometry (ICP-MS) and its advantages and limitations over other multi-element instrumental techniques are reviewed. Extended capabilities by hyphenating ICP-MS to various other well-known sample introduction techniques such as flow-injection, electrothermal vaporization, chromatographic methods and laser ablation are discussed in brief. The recent development of high resolution multi-collector double-focusing magnetic mass spectrometer with inductively coupled plasma at atmospheric pressure as source is also discussed. Some of the areas where more developments can be expected in future are suggested. (author). 77 refs., 4 tabs., 3 figs

  20. Novel applications of high performance ion chromatography-inductively coupled plasma mass spectrometry (HPIC-ICP-MS)

    International Nuclear Information System (INIS)

    This work demonstrates the development of highly sensitive and selective analytical methods, which make use of the hyphenation of high performance ion chromatography (HPIC) to inductively coupled plasma sector field mass spectrometry (ICP-SFMS). On-line coupling a chromatographic separation method with an elemental detection method provides two advantages: (1) the components of a possibly interfering matrix can be separated allowing accurate and precise ultra trace analysis of the element of interest and (2) elemental species of an element can be separated and quantified. In this work, matrix separation methods for interference free determination of 232Th, 234U, 235U and 238U in geological matrices were developed and employed. Furthermore HPIC-ICP-SFMS was applied for ultra trace analysis of Pd in environmental and geological matrices. The usefulness of HPIC-ICP-SFMS for speciation studies was demonstrated by investigating the interaction of an anti-cancer drug (cisplatin) with guanosine monophosphates. (author)

  1. Novel applications of high performance ion chromatography - inductively coupled plasma mass spectrometry (HPIC-ICP-MS)

    International Nuclear Information System (INIS)

    This work demonstrates the development of highly sensitive and selective analytical methods, which make use of the hyphenation of high performance ion chromatography (HPIC) to inductively coupled plasma sector field mass spectrometry (ICP-SFMS). On-line coupling a chromatographic separation method with an elemental detection method provides two advantages: (1) The components of a possibly interfering matrix can be separated allowing accurate and precise ultra trace analysis of the element of interest and (2) elemental species of an element can be separated and quantified. In this work, matrix separation methods for interference free determination of 232Th, 234U, 235U and 238U in geological matrices were developed and employed. Furthermore HPIC-ICP-SFMS was applied for ultra trace analysis of Pd in environmental and geological matrices. The usefulness of HPIC-ICP-SFMS for speciation studies was demonstrated by investigating the interaction of an anti-cancer drug (cisplatin) with guanosine monophosphates. (author)

  2. Gas chromatography-mass spectrometry metabolomics of goat milk with different polymorphism at the αS1-casein genotype locus.

    Science.gov (United States)

    Caboni, Pierluigi; Murgia, Antonio; Porcu, Alessandra; Demuru, Martina; Pulina, Giuseppe; Nudda, Anna

    2016-08-01

    Hyphenated gas chromatography-mass spectrometry (GC-MS) and multivariate data analysis techniques were used to uncover milk metabolite differences in different αS1-casein genotypes of goats. By a discriminant GC-MS metabolomics approach, we characterized milk polar metabolites of 28 goats. Animals were selected on the basis of their genotypes as 7 goats classified heterozygous for weak or null alleles, 5 for the genotype EE, 9 for the genotypes AE and BE, and finally 7 for the strong genotype AA. Low molecular weight polar metabolite profile was tightly related to the different goat genotypes, milk production, and protein levels. Results of multivariate statistical analysis of GC-MS data demonstrate that different heterozygous and homozygous genotypes expressed different metabolites such as citric and aconitic acid for the strong allele class with different sugars and polyols for the weak class. PMID:27289154

  3. 36. Colloquium Spectroscopicum Internationale

    International Nuclear Information System (INIS)

    The CSI36 conference will be held at the ELTE Convention Centre. In accordance with traditions, the programme consisted of invited plenary and keynote lectures, as well as oral and poster sessions. The scope of the conference, which encompasses the following fields of spectroscopy: Atomic plasma spectrometry (ICP, GD, AAS, etc.); Molecular spectrometry (UV-Vis, NMR, Raman, IR, etc.); Organic and inorganic mass spectrometry (TIMS, MALDI, LC-MS, GC-MS); X-ray spectrometry (XRF, XRD, XANES, PIXE, etc.); Hyphenated techniques; Laser spectroscopy; Imaging techniques; Nuclear techniques (Moessbauer spectroscopy, gamma spectroscopy, NAA); Quality control and chemometry. Contributions describing applications of the above spectroscopy techniques are also highly encouraged, such as in the area of: Material sciences (micro, surface and interface analysis); Environmental and geochemical analysis; Archaeometry and cultural heritage; Biological applications; Food analysis; Clinical and pharmaceutical analysis; Speciation; Mass spectrometry in post-genomics and proteomics; Miniaturisation and nano-technology. (S.I.)

  4. Vigo, vulgo Almereyda e Jean Vigo: Paulo Emílio Salles Gomes e a interlocução entre anarquismo e cinema

    Directory of Open Access Journals (Sweden)

    Julierme Sebastião Morais

    2009-11-01

    Full Text Available

    Resenha: Usabilidade tem sido um dos fatores utilizados por empresas para conquistar novos usuários (consumidores. De acordo com a Norma 9241-11 da ISO (International Organization for Standardization, a usabilidade é definida como “The extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency, and satisfaction in a specified context of use”. Esses objetivos compreendem a base do que é denominado “user experience”. Mas, o que é user experience? Trata-se da experiência do usuário quando interage com produtos ou serviços. Um produto pode ser qualquer coisa como, por exemplo, um notebook, um aparelho celular ou smartphone, um painel de automóvel ou software. Qualquer desses produtos ou até serviços (como oferecidos em web sites, têm a usabilidade como atributo determinante da qualidade perceptível aos usuários. Nesse sentido, o objetivo deste artigo é discutir e explorar experiência e percepção do usuário no uso e adoção de novas tecnologias. O artigo destaca como a Apple tem inovado em seus produtos provendo usabilidade levando em consideração a experiência do usuário.

  5. Um gramsciano a serviço da união dos povos

    Directory of Open Access Journals (Sweden)

    Marco Aurélio Nogueira

    2010-02-01

    Full Text Available Quarta-feira, 20 de janeiro, soube da morte de Giorgio Baratta. Poucos brasileiros sabem quem foi ele. Era conhecido e admirado por marxistas gramscianos, com quem mantinha relações estreitas, aqui no Brasil e em diversas partes do mundo. A todos encantava com sua ironia fina, seu conhecimento enciclopédico, sua admiração incondicional por Gramsci – uma admiração que não o cegava nem o fechava em tolos dogmatismos.

  6. Relevance of two-dimensional gas chromatography and high resolution olfactometry for the parallel determination of heat-induced toxicants and odorants in cooked food.

    Science.gov (United States)

    Giri, Anupam; Khummueng, Weeraya; Mercier, Frédéric; Kondjoyan, Nathalie; Tournayre, Pascal; Meurillon, Maïa; Ratel, Jérémy; Engel, Erwan

    2015-04-01

    The assessment of the dual impact of heating treatments on food safety and aroma is a major issue for the food sector. The aim of the present study was to demonstrate the relevance of multidimensional GC techniques, olfactometry and mass spectrometry for the parallel determination of process-induced toxicants and odorants in food starting with cooked meat as a food model. PAHs were analyzed by comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry after extraction by accelerated solvent extraction (ASE-GC × GC-TOF/MS). Odour-active compounds were determined by dynamic headspace-GC hyphenated with eight booth olfactometry and mass spectrometry (DH-GC-MS/8O) and DH-heart-cutting multidimensional GC hyphenated with olfactometry and mass spectrometry (DH-GC-GC-MS/O). For PAH determination, the GC × GC conditions consisted of a combination of a primary non-polar BPX-5 column and a secondary polar BPX-50 column, and a modulation period of 5s. In terms of linearity (R(2) ranging from 0.985 to 0.997), recovery rate (84-111%) and limit of detection (5-65 ng/kg of cooked meat), the ASE-GC × GC-TOF/MS method was found consistent with the multiresidue determination of 16 PAHs including benzo[a]pyrene in cooked meat. For aroma compounds, DH-GC-MS/8O and DH-GC-MS/O revealed 53 major meat odour-active compounds. A customized heart-cutting GC-GC-MS/O enabled the coeluting odour zones with high odour-activity to be resolved and revealed 15 additional odour-active compounds. Finally, these developments of multidimensional approaches were used to investigate the balance between 16 PAHs and 68 odour-active compounds generated with different cooking techniques. PMID:25728653

  7. Steam Methane Reforming System for Hydrogen Production: Advanced Exergetic Analysis

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    Tatiana Morosuk

    2012-02-01

    Full Text Available Steam methane reforming (SMR is one of the most promising processes for the production of hydrogen. Therefore, the overall thermodynamic efficiency of this process is of particular importance. The thermodynamic inefficiencies in a thermal system are related to exergy destruction and exergy loss. However, a conventional exergetic analysis cannot evaluate the mutual interdependencies among the system components nor the real potential for improving the energy conversion system being considered. One of the tools under development for the improvement of energy conversion systems from the thermodynamic viewpoint is the advanced exergetic analysis. In this paper, the avoidable part of the exergy destruction is estimated and the interactions among components of the overall system are evaluated in terms of endogenous and exogenous exergy destruction. The assumptions required for these calculations are discussed in detail, especially for those components that are typically used in chemical processes. Results of this paper suggest options for increasing the thermodynamic efficiency of hydrogen production by steam-methane reforming.

  8. Analytical environmental nanotechnology. Functional and chemical multielemental speciation in natural and engineered nanoparticles

    International Nuclear Information System (INIS)

    Complete text of publication follows. Nanoscale materials find use in a variety of different areas such as electronic, biomedical, sensing sciences, pharmaceutical, cosmetic, energy, environmental, catalytic and material applications. The environmental nanoparticles (NPs) can be classified in two groups: Natural NPs and Engineered or Anthropogenic NPs. Today the development of analytical methods for physical and chemical characterization of nanoparticles is still in its infancy .The natural and the engineered NPs can be investigated with an integrated analytical methodology by using several complementary techniques . We will show our experimental results on new analytical methodology to investigate the rol of the elements Cd, Cr, Cu, Hg, Ni, Pb, Zn, As, Co, Mo, Al, B, Fe, Mn, Sb, Sn, Ti, V in Organic and Inorganic Nanoparticles, by using specially hyphenated techniques like as: AsFIFFF-ICP-MS, AsFIFFF-UV.VIS, HPLC-SEC-UV.VIS-ICP-MS, PAGE-ICP-MS, PAGE-LA-ICP-MS, and Solid NPs Voltametry . The application of mathematical deconvolution to the fractograms to refine analytical signals provides a high resolution and the determination of polydispersity of particles as a very interesting information. The obtained results give a useful information about the Bioavailability, Mobility and Toxicity of the elements associated to nanoparticles. We will show also the experimental results and conclusions about the use of these hyphenated techniques to develop analytical methodology from three important point of view: Particle Size-Particle Kind and Chemical Composition, to establish a model of Functional Speciation of engineered nanoparticles like colloidal silver, and several nano-biocolloids from aquatic pseudo-multiphases. The work has been supported by Spanish Department of Science (Project CTQ 2006-00894 BQU).

  9. Ministério do Turismo e sua Festa de Babette

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    João dos Santos Filho

    2010-05-01

    Full Text Available Não sei por que! Mas quando estava pensando na Política Nacional de Turismo, visualizei um banquete, onde a prática gastronômica explicitava inexistir a plena felicidade sem o pecado, que pode ser o da gula em razão da comida e do dinheiro pela existência das emendas parlamentares. O Ministério do Turismo seria madame Babette em seu banquete articulado por um maquiamento marqueteiro, buscando contrapor a noção do pecado com a idéia da felicidade.

  1. Criatividade em ação: reclusão na busca do momento criativo

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    Antonio Mendes da Silva Filho

    2011-09-01

    Full Text Available Criatividade, intuição, imaginação, determinação, ambição compreendem atributos que podem caracterizar um intelecto humano. As pessoas, no dia-a-dia, fazem uso desses ingredientes em variados momentos onde precisam tomar decisões e/ou prover soluções a problemas, além de empregá-las no processo de inovação. Entretanto, ao observar o ‘caminhar’ das pessoas e das organizações, percebe-se que o momento atual e vindouro é enriquecido e apoiado por intensos mecanismos de comunicação. A comunicação é essencial para solucão de problemas, para educação e uma miríade de atividades. Todavia, num momento da busca de solução ou num momento criativo, a reclusão pode constituir um diferencial. Nesse sentido, este artigo discute e explora esse paradoxo (se assim puder ser denominado de querer estar junto (com intensa comunicação ou recluso na busca do momento criativo ou solução de problema.

  2. In situ monitoring, separation, and characterization of gold nanorod transformation during seed-mediated synthesis.

    Science.gov (United States)

    Nguyen, Thao M; Pettibone, John M; Gigault, Julien; Hackley, Vincent A

    2016-03-01

    The control of gold nanorod (GNR) solution-based syntheses has been hindered in part by the inability to examine and control the conversion of precursor seed populations to anisotropic materials, which have resulted in low yields of desired products and limited their commercial viability. The advantages offered by tandem separation and characterization methods utilizing asymmetric-flow field flow fractionation (A4F) are principally achieved as a result of their non-disruptive nature (minimizing artefacts), fast throughput, and in-situ analysis. With hyphenated A4F methods, resolved populations of seeds and secondary products, up to long aspect ratio rods, have been achieved and exemplify progress towards elucidating mechanistic aspects of formation and thus rational design. While there have been previously reported studies on A4F separation of GNRs, to our knowledge, this is the first published investigation of in situ GNR growth, separation, and characterization based on A4F, where its utilization in this capacity goes beyond traditional separation analysis. By using hydroquinone as the reducing agent, the conversion of the initial seed population to a distribution of products, including the GNRs, could be monitored in real time using A4F hyphenated with a diode array detector. Transmission electron microscopy confirms that the number of peaks observed during fractionation corresponds with size and shape dispersity. This proof-of-principle study introduces A4F as a technique that establishes a foundation for future mechanistic studies on the growth of GNRs from gold seeds, including conversion of the seed population to initial products, a topic highly relevant to advancing progress in nanomanufacturing. Graphical Abstract ᅟ. PMID:26873210

  3. Recent advances and trends in the liquid-chromatography-mass spectrometry analysis of flavonoids.

    Science.gov (United States)

    de Villiers, André; Venter, Pieter; Pasch, Harald

    2016-01-22

    Flavonoids have elicited significant attention as a result of their importance in plants, their influence on the properties of natural-product derived commodities and especially as a consequence of their purported health benefits. Research in all of these fields relies heavily on accurate analytical data, and in this LC-MS has come to play an influential role by allowing relatively fast tentative identification and accurate quantification of low levels of flavonoids in a variety of matrices. The field has undergone rapid expansion in the last decade due to important developments in both HPLC and MS instrumentation, which nowadays allow much faster and more accurate analysis of flavonoids. This contribution aims to provide an overview of these developments and their application in flavonoid analysis since 2009. The discussion is focussed first on methodologies which provide improved LC separation of flavonoids in terms of speed and/or resolution, including ultra high pressure LC (UHPLC), monolithic and superficially porous phases, high temperature LC (HTLC) and comprehensive two-dimensional LC (LC×LC). The fundamental background relevant to each of these will be briefly outlined, as well as the implications and promise of their hyphenation to MS. Secondly, the possibilities and limitations of a range of the latest MS instruments available in combination with advanced LC analysis will be discussed, including ion trap, triple quadrupole, time-of-flight, Orbitrap, ion mobility and various hybrid instruments. Examples from the latest literature will be used to illustrate the performance gains achievable in flavonoid analysis by the hyphenation of advanced LC separation and high-end MS instrumentation. PMID:26718188

  4. Notas sobre a liberdade e a tirania da maioria em Stuart Mill

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    Antonio Ozaí da Silva

    2009-10-01

    Full Text Available O liberalismo é uma doutrina política que, em suas origens, tem como alicerce vários autores clássicos do pensamento político: Locke, Montesquieu, Kant, Adam Smith, Humboldt, Benjamin Constant, Alexis de Tocqueville, Stuart Mil e outros. Portanto, a exemplo do socialismo, cabe perfeitamente a pergunta: Qual liberalismo? Como o(s marxismo(s, o pensamento liberal não é homogêneo. Da mesma forma, o conceito de liberdade no pensamento liberal tem mais de uma conotação, como também a sua crítica. Estes apontamentos se limitam a expor o pensamento político de John Stuart Mill, mais precisamente sobre a sua argumentação em defesa da liberdade individual e a crítica à tirania da maioria no ensaio “Sobre a Liberdade” (MILL, 1991.

  5. Étude préliminaire sur les stucs trouvés dans le "Bâtiment à Péristyle" du quartier sud-ouest de Palmyre (PAL.M.A.I.S. - Fouilles 2008-2009 A preliminary study on the stuccos found in the "Peristyle Building" of Palmyra's south-west quarter (PAL.M.A.I.S. - Excavations 2008-2009

    Directory of Open Access Journals (Sweden)

    Lilia Palmieri

    2011-03-01

    Full Text Available

    The Italian-Syrian joint Mission of the Università degli Studi of Milan at Palmyra (Pal.M.A.I.S. = Palmira. Missione Archeologica Italo-Siriana is focus on the exploration of the south-west quarter of the ancient city. Since 2008 the stratigraphic excavation of the "Peristyle Building" has begun. Many fragments of stucco which are part of a frieze decorated by an Anthemion have been found in one room of the building - the room A -. These fragments belong to the decoration of a luxury complex which was damaged (or destroyed? before the 6th century AD, and they are very important elements in order to define the chronological horizon of the first phase of development of the area.

    Les travaux archéologiques de la Mission conjointe italienne-syrienne de l'Università degli Studi de Milan à Palmyre (Pal.M.A.I.S.= Palmira. Missione Archeologica Italo-Siriana sont dédiés à l’exploration du quartier sud-ouest de la ville antique. Depuis 2008 a été entreprise la fouille stratigraphique du "Bâtiment à Péristyle", et dans une

  6. Visualisation of cerebrospinal fluid flow patterns in albino Xenopus larvae in vivo

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    Mogi Kazue

    2012-04-01

    Full Text Available Abstract Background It has long been known that cerebrospinal fluid (CSF, its composition and flow, play an important part in normal brain development, and ependymal cell ciliary beating as a possible driver of CSF flow has previously been studied in mammalian fetuses in vitro. Lower vertebrate animals are potential models for analysis of CSF flow during development because they are oviparous. Albino Xenopus laevis larvae are nearly transparent and have a straight, translucent brain that facilitates the observation of fluid flow within the ventricles. The aim of these experiments was to study CSF flow and circulation in vivo in the developing brain of living embryos, larvae and tadpoles of Xenopus laevis using a microinjection technique. Methods The development of Xenopus larval brain ventricles and the patterns of CSF flow were visualised after injection of quantum dot nanocrystals and polystyrene beads (3.1 or 5.8 μm in diameter into the fourth cerebral ventricle at embryonic/larval stages 30-53. Results The fluorescent nanocrystals showed the normal development of the cerebral ventricles from embryonic/larval stages 38 to 53. The polystyrene beads injected into stage 47-49 larvae revealed three CSF flow patterns, left-handed, right-handed and non-biased, in movement of the beads into the third ventricle from the cerebral aqueduct (aqueduct of Sylvius. In the lateral ventricles, anterior to the third ventricle, CSF flow moved anteriorly along the outer wall of the ventricle to the inner wall and then posteriorly, creating a semicircle. In the cerebral aqueduct, connecting the third and fourth cerebral ventricles, CSF flow moved rostrally in the dorsal region and caudally in the ventral region. Also in the fourth ventricle, clear dorso-ventral differences in fluid flow pattern were observed. Conclusions This is the first visualisation of the orchestrated CSF flow pattern in developing vertebrates using a live animal imaging approach. CSF flow

  7. A proposito di arredi. Prima e dopo la tenda di Tolomeo Filadelfo About furniture. Before and after Ptolomaeus Philadelphos' pavilion

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    Elena Calandra

    2010-07-01

    Full Text Available

    The furniture is of primary importance towards the canopies definition, more than the architectonic structure: they  contribute, in fact, in creating and organizing the spaces, so that there is almost no distinction between furniture and structure, as it is possible to observe in the ancient sources of different periods (Herodotus, Euripides, Julius Caesar, Plutarchus, Athenaeus: the pavilions of Xerxes at Plataia, of Ion at Delphi, of Alexander after the Issa battle and at Susa, of Pompey at Pharsalos, as well as the Ptolomaeus's canopy at Alexandria.

    At the same time, the furniture language is studied, signifying the power and the force of the sovereign through the luxurious materials and surprising the spectators.

         At the end, some hypotheses on the final destination of the furniture, after dismantling the Ptolomaeus' canopy, equiped for one year. 

    Soil biochemical attributes can be used as sensitive indicators of alterations promoted by the agricultural use, being a tool to guide tillage practices planning and evaluation to maintain soil sustainability. The objective of this study was to evaluate alterations in the soil organic carbon, biomass and microbial activity, urease and acid phosphatase activity, in two savannah soils, as affected by soil management systems. The study consisted of five soil management systems in a Typic Quartzipsamment, four in an Oxisol, and reference areas without alterations in the two soil types. The management systems changed the biochemical attributes of both soils. The Typic Quartzipsamment area under the soybean/Brachiaria decumbens sequence decreased the soil organic carbon and the microbial biomass carbon, and increased the respiration and qCO2, while the Oxisol, in all the areas, except for pasture, promoted reductions in the biochemical attributes. Among the management systems studied,  the pasture provided improvements in the evaluated attributes, in both soils.

    KEY-WORDS: Soil quality; microbial biomass; soil enzymatic activity.

    The article questions the usual views on migration, which characterize it merely as the provisional movement of foreign labor and obscure its fundamentally political meaning

  8. Os perigos da utopia

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    Larry Hufford

    2009-06-01

    Full Text Available

    A utopia pode ter um lado que eleva e um lado sinistro, mas geralmente o lado sinistro acaba destruindo o idealismo inicial. A razão para isto é que os utópicos inevitavelmente adotam uma imagem messiânica do mundo. As três revoluções messiânicas na história—a americana, a francesa e a bolchevique—foram lideradas por homens que pensavem que suas idéias eram universais. Este ensaio examina os escritos do existencialista francês Albert Camus, que argumenta que não existem valores transcendentais, ao mesmo tempo que ele não aceita o niilismo. Camus faz uma distinção entre um rebelde e um revolucionário, e conclui que uma rebelião tentará terminar com uma opressão espedífica, enquanto que uma revolução tentará criar “um novo

  9. Nem tanto ao céu, nem tanto a terra: limites e possibilidades da lei de incentivo fiscal à cultura

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    Marcelo Gruman

    2010-04-01

    Full Text Available

    O artigo reflete sobre o papel das leis de incentivo fiscal como instrumento de políticas públicas para a cultura, apresentando um breve histórico de sua existência. Argumenta, a partir de gráficos comparativos, que a utilização deste mecanismo não conseguiu democratizar a contento o acesso à produção e à fruição cultural por parte da população brasileira, fato este que resultou na proposta de reformulação da chamada Lei Rouanet a partir de amplo debate entre o Ministério da Cultura e a sociedade civil.

  10. Conventional Exergetic and Exergoeconomic Analyses of a Power Plant with Chemical Looping Combustion for CO2 Capture

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    Tatiana Morosuk

    2010-09-01

    Full Text Available

    Exergy-based methods can be used as a tool for examining, comparing and assessing thermodynamic systems. In this paper, an exergoeconomic analysis is used to evaluate a power plant with chemical looping combustion (CLC for CO2 capture. This oxy-fuel plant is compared, from an exergetic and an economic perspective, to a conventional, reference power plant without CO2 capture. The exergetic analysis shows decreased exergy destruction in the CLC reactors, compared to the exergy destruction in the conventional combustion chamber of the reference case; thus, the irreversibilities caused by combustion in the CLC are reduced. However, due to the addition of the CO2 compression unit, the overall exergetic efficiency of the plant with CLC is lower than that of the reference plant by approximately 5 percentage points. The economic analysis confirms a significant increase in the investment cost of the CO2 capture plant, due to the addition of the units for CO2 compression and CLC. Thus, the cost of electricity is 24% higher for this plant in comparison to that of the reference case. Nevertheless, when compared to the reference plant with CO2 capture with monoethanolamine, the plant with CLC was found to be a more economical option. Since CO2 abatement must be realized in the future, given expected environmental or tax measures, CLC provides relatively low cost carbon dioxide capture and it, therefore, appears to be a promising option for

  11. A abordagem de Morin frente à construção do todo

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    Paloma Maria Santos

    2009-08-01

    Full Text Available

    O objetivo deste artigo é apresentar uma reflexão sobre a abordagem de Edgar Morin frente a construção do conhecimento. Partindo das transformações que podem ocorrer dentro de um sistema complexo, Morin discorre sobre três pressupostos relacionados a interação entre partes e todo, que irão conduzir o desenvolvimento deste trabalho.

  12. Violence Research from North Africa to South Asia: A Historical and Structural Overview

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    Jochen Hippler

    2011-07-01

    Full Text Available

    This is a historical and sociological overview of violence and violence research in and on North Africa, West Asia, and South Asia, considering only studies for a global audience. The main focus is on political violence, with a brief look at religious and communal violence, youth violence, and domestic and gendered violence. These regions have been consistently affected by political violence for many decades, the main source of which seems to be the ongoing state formation process, as well as social transformation in general. The literature on violence is dominated by international debates, at

  13. The dangers of Utopia

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    Larry Hufford

    2009-06-01

    Full Text Available

    Utopia can have an uplifting and a dark side, but usually the dark side ends up trumping the initial idealism. The reason for this is that utopians inevitably adopt a messianic image of the world. The three messianic revolutions in history—the American, French and Bolshevik—were led by men who thought their ideas were universal. This essay examines the writings of French existentialist Albert Camus, who argues that there are no transcendental values, at the same time he does not accept nihilism. Camus makes a distinction between a rebel and a revolutionary, and concludes that a rebellion will try to end the specific oppression, whereas the revolution will try to create a “new man,” with common values throughout the world.

  14. Ciência, pseudociência e o fascínio popular

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    Raymundo de Lima

    2010-03-01

    Full Text Available

    Rádio, televisão e internet divulgam fórmulas milagrosas para tratar calvície, emagrecer, até para aumentar o tamanho do pênis. Técnicas bizarras ensinam a aplicar o próprio sangue [hemoterapia?], tomar a própria unina [urinoterapia?], viver apenas tomando luz [helioterapia?] etc.

  15. La endoscopia digestiva superior en la Atención Primaria de Salud

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    Marcos Félix Osorio Pagola

    2010-11-01

    Full Text Available

    .


  16. A História do Ensino do Espanhol na década de 1980-1990 no Estado do Paraná

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    Jonathas de Paula Chaguri

    2011-04-01

    Full Text Available

    Este trabalho tem como objetivo apresentar os (des caminhos que levaram o estado do Paraná a um momento de reformulação em sua grade curricular, levando a saída do Espanhol como componente curricular do Colégio Estadual em Curitiba na década de 1980 e voltando a sua oferta no final da mesma década com a criação do CELEM em todo estado. Por conseguinte, o espanhol vem se solidificando em todo estado do Paraná, após a criação da Lei nº. 11.161 sancionado pelo Presidente Luiz Inácio Lula da Silva, que dispõe sobre o ensino do espanhol como componente curricular obrigatório nas escolas de ensino médio de todo o país.

  17. Separation of pigment formulations by high-performance thin-layer chromatography with automated multiple development.

    Science.gov (United States)

    Stiefel, Constanze; Dietzel, Sylvia; Endress, Marc; Morlock, Gertrud E

    2016-09-01

    Food packaging is designed to provide sufficient protection for the respective filling, legally binding information for the consumers like nutritional facts or filling information, and an attractive appearance to promote the sale. For quality and safety of the package, a regular quality control of the used printing materials is necessary to get consistently good print results, to avoid migration of undesired ink components into the food and to identify potentially faulty ink batches. Analytical approaches, however, have hardly been considered for quality assurance so far due to the lack of robust, suitable methods for the analysis of rarely soluble pigment formulations. Thus, a simple and generic high-performance thin-layer chromatography (HPTLC) method for the separation of different colored pigment formulations was developed on HPTLC plates silica gel 60 by automated multiple development. The gradient system provided a sharp resolution for differently soluble pigment constituents like additives and coating materials. The results of multi-detection allowed a first assignment of the differently detectable bands to particular chemical substance classes (e.g., lipophilic components), enabled the comparison of different commercially available pigment batches and revealed substantial variations in the composition of the batches. Hyphenation of HPTLC with high resolution mass spectrometry and infrared spectroscopy allowed the characterization of single unknown pigment constituents, which may partly be responsible for known quality problems during printing. The newly developed, precise and selective HPTLC method can be used as part of routine quality control for both, incoming pigment batches and monitoring of internal pigment production processes, to secure a consistent pigment composition resulting in consistent ink quality, a faultless print image and safe products. Hyphenation of HPTLC with the A. fischeri bioassay gave first information on the bioactivity or rather

  1. Integrated geophysical measurements on a test site for detection of buried steel drums

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    Alessandro Settimi

    2011-04-01

    Full Text Available Geophysical methods are increasingly used to detect and locate illegal waste disposal and buried toxic steel drums. This study describes the results of a test carried out in clayey-sandy ground where 12 empty steel drums had previously been buried at 4-5 m below ground level. This test was carried out with three geophysical methods for steel-drum detection: a magnetometric survey, electrical resistivity tomography with different arrays, and a multifrequency frequency-domain electromagnetic induction survey. The data show that as partially expected, the magnetometric and electromagnetic induction surveys detected the actual steel drums buried in the subsurface, while the electrical resistivity tomography mainly detected the changes in some of the physical properties of the terrain connected with the digging operations, rather than the actual presence of the steel drums.
    O primeiro ano de Barak Obama à frente do governo americano foi um ano de grandes dificuldades, não só para ele, mas também para o seu partido democrata. Não só para os democratas, mas também para o povo americano. Não só para o povo americano, mas também para o povo iraquiano, e o povo do Afeganistão. E, por extensão, para todas as pessoas do mundo que ouviram seu discurso de aceitação do cargo, no dia 20 de janeiro de 2009. Os únicos que não sofreram, pelo que pude averiguar ouvindo rádio, lendo jornais e assistindo as notícias, foram os comentaristas republicanos, especialmente os ligados à tropa da cadeia de televisão Fox. Para eles, foi um ano de exultação.  Só não foi melhor porque o país não sofreu um ataque terrorista de

  2. Afinidades eletivas: EZLN e MST na contramão da história do progresso dos vencedores

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    Fabio Querido

    2011-04-01

    Full Text Available

    Inspirando-se em algumas reflexões de Walter Benjamin e, em menor medida, de José Carlos Mariátegui, o objetivo deste pequeno artigo é esboçar algumas afinidades eletivas entre o Exército Zapatista de Libertação Nacional e o Movimento dos Trabalhadores Sem Terra, particularmente no que se refere à importância que eles conferem ao resgate e rememoração das lutas sociais do passado – transformadas em fonte de inspiração das lutas do presente.

  3. Cuando parten las ideas. Exilio y transformaciones del campo intelectual

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    Lorena Soler

    2008-09-01

    Full Text Available A propósito de ";El exilio intelectual en México. Notas sobre la experiencia argentina 1974-1983"; de José María Casco.

  4. Exergoeconomic optimization of an Organic Rankine Cycle for low-temperature geothermal heat sources

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    Dieter Brüggemann

    2012-05-01

    Full Text Available

    An exergoeconomic analysis of a geothermal power generation for a low-temperature resource is performed. An Organic Rankine Cycle (ORC with isobutane and isopentane as working fluids is considered as binary power plant. A systematic parameter variation is done for the minimum temperature difference in the evaporator and condenser. The most suitable design parameters are evaluated under exergetic, economic and exergoeconomic criteria. The specific costs of electricity generation are minimal for the use of isobutane as working fluid and minimal temperature difference of 3 K at evaporation and 7 K at condensation. The most suitable concept for isopentane leads to only 0.4

  5. Educar-se ao mundo: percepções acerca das africanidades

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    Paulo César Antonini de Souza

    2010-03-01

    Full Text Available

    O presente ensaio tem a intenção de apresentar algumas reflexões sobre o estudo das africanidades nas instituições de ensino. Buscando referência nas legislações que determinam essa abordagem, o texto faz um percurso histórico sobre elementos que viabilizam sua necessidade de inserção, na expectativa de que os educadores lancem um novo olhar a respeito da educação pela diversidade, assim como para os significados e sentidos do educar-se, segundo a perspectiva africana, em relação aos afro-descendentes brasileiros.

  6. In-line sequential injection-based hollow-fiber sorptive microextraction as a front-end to gas chromatography-mass spectrometry: a novel fully automatic sample processing technique for residue analysis.

    Science.gov (United States)

    Boonjob, Warunya; Quintana, José Benito; Rodil, Rosario; Cela, Rafael; Miró, Manuel

    2013-10-01

    A novel and affordable analytical setup is herein reported for automatic flow-through sorptive microextraction of organic contaminants, exploiting polydimethylsiloxane (PDMS) as a front-end to gas chromatography-ion trap-tandem mass spectrometry. The analytical procedure involves a short single-strand PDMS hollow fiber integrated in a sequential injection (SI) network for automatic fluidic handling by programmable flow. The target species are in-line extracted from 10 mL of sample containing 20% (v/v) methanol followed by elution with a metered volume of organic solvent, which is whereupon quantitatively transferred into the programmed temperature vaporization (PTV) injector of the GC. Diffusional resistance to mass transfer was overcome by effecting the overall concentration and stripping steps at a single PDMS tubing interface. The proof of concept of the novel hyphenated system was demonstrated for extraction and determination of organochlorine pesticides (OCPs), namely, heptachlor, dieldrin, endrin, endosulfan, p,p'-dichlorodiphenyldichloroethane, p,p'-dichlorodiphenyltrichloroethane, dichlorodiphenyldichloroethylene, and endrin ketone, taken as model analytes, in environmental and industrial waters. Four organic solvents with a broad spectrum of polarity were investigated as eluents in the SI-based assembly, namely, ethyl acetate, methyl tert-butyl ether, hexane, and chloroform. Chloroform was proven the most suitable solvent for expedient elution and fast evaporation in the PTV injector. Under the selected experimental variables, limits of detection (signal-to-noise ratio (S/N) = 3) within the range of 0.3-1.1 ng L(-1), limits of quantification (S/N = 10) of 1.0-3.6 ng L(-1), and method repeatabilities spanning from 1.7 to 4.7% were obtained for the suite of OCPs. The hyphenated flow analyzer was harnessed to the analysis of samples of varying matrix complexity with good relative recoveries (86-112%) in drinking water, surface water, and influent and effluent

  7. İMPLANTOLOJİDE DOKU MÜHENDİSLİĞİ VE GEN TEDAVİSİ

    Directory of Open Access Journals (Sweden)

    Erman Bülent Tuncer

    2011-01-01

    Full Text Available

    Son elli yılda implantoloji alanında büyük adımlar atılmıştır. Günümüzde implantın kemik ile bağlantısı kabul edilebilir derecede başarılı olmasına rağmen inflamasyon, trombozis, fibrozis ve enfeksiyon gibi komplikasyonlar görülebilmektedir. Genetik ve doku mühendisliği alanındaki gelişmelerle birlikte ileri çalışmalara ihtiyaç duyulmaktadır. Görülen komplikasyonları en aza indirmek için implantın yerleştirildiği dokunun yanıtının istenilen düzeyde ve şekilde olması ve immün reaksiyonun düzenlenmesi gerekmektedir. Ayrıca doku mühendisliği ile implantın yerleştirilmesi için, kaybedilen alveolar kemik dokusunun yeniden oluşturulması ya da genişletilmesi mümkün hale gelmiştir.

  8. Acusar ou não acusar? In dubio pro societate é (? a solução. Uma forma perversa de lidar com a dúvida no processo penal brasileiro

    Directory of Open Access Journals (Sweden)

    Marcio Ferreira Rodrigues Pereira

    2011-02-01

    Full Text Available No âmbito do Direito Processual Penal, em pelo menos dois momentos marcantes da persecução penal em juízo (recebimento da denúncia e decisão de pronúncia, a fórmula in dubio pro societate vem sendo repetida à exaustão por significativo setor da comunidade jurídica. A pretensão deste estudo é desvelar tanto o caráter perverso que tal discurso encobre como a carência de base constitucional para o referido brocardo.

  9. Are you kidding me? Are you kidding me?

    Directory of Open Access Journals (Sweden)

    Rosanna Lauriola

    2010-04-01

    Full Text Available Are you kidding me?

    The presence of a picture such as the one that appears in the site (http://farm4.static.flickr.com/3252/2843406747_3c135d63d9.jpg?v=0 brings to mind both the enormous efforts made throughout many years to raise awareness about the dangers or rape, and the horrors of rape for women all over the world. To joke with such a subject is offensive both for people—men and women—who have been struggling for so long, and for the victims of this crime. People who use the subject of rape for fun cause immense pain and immense damage.

  10. Identification of Polish cochineal (Porphyrophora polonica L.) in historical textiles by high-performance liquid chromatography coupled with spectrophotometric and tandem mass spectrometric detection.

    Science.gov (United States)

    Lech, Katarzyna; Jarosz, Maciej

    2016-05-01

    The present work reports a method for identification of Polish cochineal (Porphyrophora polonica L.) in historical fabrics by the use of high-performance liquid chromatography coupled with diode array and tandem mass spectrometric detection with electrospray ionization (HPLC-DAD-ESI MS/MS). This hyphened technique allows detection and identification of 16 new minor colorants present in the discussed scale insect (including two previously observed by Wouters and Verhecken (Ann Soc Entomol Fr. 1989;25:393-410), but specified only as compounds of unknown structures) that do not occur (e.g., in American cochineal). The MS/MS experiments, complemented with UV-VIS data, enable identification of mono- and di-, C- and O-hexosides of kermesic and flavokermesic acids or their derivatives. The present paper introduces a fingerprint of color compounds present in Polish cochineal and defines them, particularly pp6 (ppI, O-hexoside of flavokermesic acid), as its markers allow distinguishing of Polish-cochineal reds from the American ones. Usefulness of the selected set of markers for identification of Polish cochineal has been demonstrated in the examination of textiles from the collection of the National Museum in Warsaw using the multiple reaction monitoring (MRM) method, originally elaborated on the basis of this study. PMID:26935929

  11. SIMULTANEOUS SELECTION FOR GENOTYPIC PRODUCTION, ADAPTABILITY, AND STABILITY IN CASHEW CLONES BY MIXED MODELS SELEÇÃO SIMULTÂNEA PARA PRODUÇÃO, ADAPTABILIDADE E ESTABILIDADE GENOTÍPICAS EM CLONES DE CAJUEIRO, VIA MODELOS MISTOS

    Directory of Open Access Journals (Sweden)

    José Jaime Vasconcelos Cavalcanti

    2009-01-01

    Full Text Available

    This work aimed to study the interaction between genotypes and environments, using the BLUP/REML procedure for evaluation of precocious cashew clones. The purpose of this work was to identify genotypes that simultaneously aggregate high productivity and

  12. Flow field thermal gradient gas chromatography.

    Science.gov (United States)

    Boeker, Peter; Leppert, Jan

    2015-09-01

    Negative temperature gradients along the gas chromatographic separation column can maximize the separation capabilities for gas chromatography by peak focusing and also lead to lower elution temperatures. Unfortunately, so far a smooth thermal gradient over a several meters long separation column could only be realized by costly and complicated manual setups. Here we describe a simple, yet flexible method for the generation of negative thermal gradients using standard and easily exchangeable separation columns. The measurements made with a first prototype reveal promising new properties of the optimized separation process. The negative thermal gradient and the superposition of temperature programming result in a quasi-parallel separation of components each moving simultaneously near their lowered specific equilibrium temperatures through the column. Therefore, this gradient separation process is better suited for thermally labile molecules such as explosives and natural or aroma components. High-temperature GC methods also benefit from reduced elution temperatures. Even for short columns very high peak capacities can be obtained. In addition, the gradient separation is particularly beneficial for very fast separations below 1 min overall retention time. Very fast measurements of explosives prove the benefits of using negative thermal gradients. The new concept can greatly reduce the cycle time of high-resolution gas chromatography and can be integrated into hyphenated or comprehensive gas chromatography setups. PMID:26235451

  13. Sulfur analysis by inductively coupled plasma-mass spectrometry: A review

    Energy Technology Data Exchange (ETDEWEB)

    Giner Martínez-Sierra, J.; Galilea San Blas, O.; Marchante Gayón, J.M.; García Alonso, J.I., E-mail: jiga@uniovi.es

    2015-06-01

    In recent years the number of applications of sulfur (S) analysis using inductively coupled plasma mass spectrometry (ICP-MS) as detector has increased significantly. In this article we describe in some depth the application of ICP-MS for S analysis with emphasis placed on the sulfur-specific detection by hyphenated techniques such as LC, GC, CE and LA coupled on-line to ICP-MS. The different approaches available for sulfur isotope ratio measurements by ICP-MS are also detailed. Particular attention has been paid to the quantification of peptides/proteins and the analysis of metallopeptides/metalloproteins via sulfur by LC–ICP-MS. Likewise, the speciation analysis of metal-based pharmaceuticals and metallodrugs and non-metal selective detection of pharmaceuticals via S are highlighted. Labeling procedures for metabolic applications are also included. Finally, the measurement of natural variations in S isotope composition with multicollector ICP-MS instruments is also covered in this review. - Highlights: • Emphasis placed on the sulfur-specific detection by chromatographic techniques coupled on-line to ICP-MS. • Different instrumental approaches available for sulfur measurements by ICP-MS. • Quantification of proteins and the analysis of metalloproteins via sulfur by LC-ICP-MS. • Labelling procedures for metabolic applications are also included. • The measurement of natural variations in S isotope composition with multicollector ICP-MS.

  14. Sulfur analysis by inductively coupled plasma-mass spectrometry: A review

    Science.gov (United States)

    Giner Martínez-Sierra, J.; Galilea San Blas, O.; Marchante Gayón, J. M.; García Alonso, J. I.

    2015-06-01

    In recent years the number of applications of sulfur (S) analysis using inductively coupled plasma mass spectrometry (ICP-MS) as detector has increased significantly. In this article we describe in some depth the application of ICP-MS for S analysis with emphasis placed on the sulfur-specific detection by hyphenated techniques such as LC, GC, CE and LA coupled on-line to ICP-MS. The different approaches available for sulfur isotope ratio measurements by ICP-MS are also detailed. Particular attention has been paid to the quantification of peptides/proteins and the analysis of metallopeptides/metalloproteins via sulfur by LC-ICP-MS. Likewise, the speciation analysis of metal-based pharmaceuticals and metallodrugs and non-metal selective detection of pharmaceuticals via S are highlighted. Labeling procedures for metabolic applications are also included. Finally, the measurement of natural variations in S isotope composition with multicollector ICP-MS instruments is also covered in this review.

  15. 铀在植物-微生物共生体系满江红体内的分布%Distribution of Uranium in the Plant_microbe Symbiotic System_Azolla Imbircata

    Institute of Scientific and Technical Information of China (English)

    胡南; 丁德馨; 潘长春; 胡劲松; 李乐; 李广悦; 王永东; 郑济芳

    2014-01-01

    采用扫描电镜( SEM)和能谱( EDS)联用分析技术,研究了铀在植物—微生物共生体系满江红中的分布,结果发现,铀在蕨类植物满江红和微生物满江红鱼腥藻中均有分布,满江红鱼腥藻中铀含量略高于蕨类植物满江红,表明了蕨类植物满江红和微生物满江红鱼腥藻都参与了去除水体中铀的过程。%The distribution of uranium in the plant_microbe symbiotic system_Azolla imbir_cata was analyzed by scanning electron microscope( SEM) and energy dispersive spectrom_eter( EDS ) hyphenated technique. The results showed that uranium distributed in both fern_Azolla imbricata and microbe_Anabena azollae. The content of uranium in Anabena azollae was slightly higher than that in Azolla imbricata. The fern_Azolla imbricata and mi_crobe_Anabena azollae had a synergistic effect on the process of removing uranium from the water.

  16. Chemometric analysis of comprehensive LC×LC-MS data: Resolution of triacylglycerol structural isomers in corn oil.

    Science.gov (United States)

    Navarro-Reig, Meritxell; Jaumot, Joaquim; van Beek, Teris A; Vivó-Truyols, Gabriel; Tauler, Romà

    2016-11-01

    Comprehensive hyphenated two-dimensional liquid chromatography mass spectrometry (LC×LC-MS) is a very powerful analytical tool achieving high throughput resolution of highly complex natural samples. However, even using this approach there is still the possibility of not resolving some of the analytes of interest. For instance, triacylglycerols (TAGs) structural isomers in oil samples are extremely difficult to separate chromatographically due to their very similar structure and chemical properties. Traditional approaches based on current vendor chromatographic software cannot distinguish these isomers from their different mass spectral features. In this work, a chemometric approach is proposed to solve this problem. First, the experimental LC×LC-MS data structure is discussed, and results achieved by different methods based on the fulfilment of the trilinear model are compared. Then, the step-by-step resolution and identification of strongly coeluted compounds from different examples of triacylglycerols (TAGs) structural isomers in corn oil samples are described. As a conclusion, the separation power of two-dimensional chromatography can be significantly improved when it is combined with the multivariate curve resolution method. PMID:27591659

  17. Method for the quantification of vanadyl porphyrins in fractions of crude oils by High Performance Liquid Chromatography-Flow Injection-Inductively Coupled Plasma Mass Spectrometry

    Science.gov (United States)

    Wandekoken, Flávia G.; Duyck, Christiane B.; Fonseca, Teresa C. O.; Saint'Pierre, Tatiana D.

    2016-05-01

    High performance liquid chromatography hyphenated by flow injection to inductively coupled plasma mass spectrometry (HPLC-FI-ICP-MS) was used to investigate V linked to porphyrins present in fractions of crude oil. First, the crude oil sample was submitted to fractionation by preparative liquid chromatography with UV detection, at the porphyrin Soret band wavelength (400 nm). The obtained porphyrin fractions were then separated in a 250 mm single column, in the HPLC, and eluted with different mobile phases (methanol or methanol:toluene (80:20; v:v)). The quantification of V-porphyrins in the fractions eluted from HPLC was carried out by online measuring the 51V isotope in the ICP-MS, against vanadyl octaethylporphine standard solutions (VO-OEP), prepared in the same solvent as the mobile phase, and injected post-column directly into the plasma. A 20 μg L- 1 Ge in methanol was used as internal standard for minimizing non-spectral interference, such as short-term variations due to injection. The mathematical treatment of the signal based on Fast Fourier Transform smoothing algorithm was employed to improve the precision. The concentrations of V as V-porphyrins were between 2.7 and 11 mg kg- 1 in the fractions, which were close to the total concentration of V in the porphyrin fractions of the studied crude oil.

  18. Handheld spectrometers: the state of the art

    Science.gov (United States)

    Crocombe, Richard A.

    2013-05-01

    "Small" spectrometers fall into three broad classes: small versions of laboratory instruments, providing data, subsequently processed on a PC; dedicated analyzers, providing actionable information to an individual operator; and process analyzers, providing quantitative or semi-quantitative information to a process controller. The emphasis of this paper is on handheld dedicated analyzers. Many spectrometers have historically been large, possible fragile, expensive and complicated to use. The challenge over the last dozen years, as instruments have moved into the field, has been to make spectrometers smaller, affordable, rugged, easy-to-use, but most of all capable of delivering actionable results. Actionable results can dramatically improve the efficiency of a testing process and transform the way business is done. There are several keys to this handheld spectrometer revolution. Consumer electronics has given us powerful mobile platforms, compact batteries, clearly visible displays, new user interfaces, etc., while telecomm has revolutionized miniature optics, sources and detectors. While these technologies enable miniature spectrometers themselves, actionable information has demanded the development of rugged algorithms for material confirmation, unknown identification, mixture analysis and detection of suspicious materials in unknown matrices. These algorithms are far more sophisticated than the `correlation' or `dot-product' methods commonly used in benchtop instruments. Finally, continuing consumer electronics advances now enable many more technologies to be incorporated into handheld spectrometers, including Bluetooth, wireless, WiFi, GPS, cameras and bar code readers, and the continued size shrinkage of spectrometer `engines' leads to the prospect of dual technology or `hyphenated' handheld instruments.

  1. The use of laser-induced fluorescence or ultraviolet detectors for sensitive and selective analysis of tobramycin or erythropoietin in complex samples

    Science.gov (United States)

    Ahmed, Hytham M.; Ebeid, Wael B.

    2015-05-01

    Complex samples analysis is a challenge in pharmaceutical and biopharmaceutical analysis. In this work, tobramycin (TOB) analysis in human urine samples and recombinant human erythropoietin (rhEPO) analysis in the presence of similar protein were selected as representative examples of such samples analysis. Assays of TOB in urine samples are difficult because of poor detectability. Therefore laser induced fluorescence detector (LIF) was combined with a separation technique, micellar electrokinetic chromatography (MEKC), to determine TOB through derivatization with fluorescein isothiocyanate (FITC). Borate was used as background electrolyte (BGE) with negative-charged mixed micelles as additive. The method was successively applied to urine samples. The LOD and LOQ for Tobramycin in urine were 90 and 200 ng/ml respectively and recovery was >98% (n = 5). All urine samples were analyzed by direct injection without sample pre-treatment. Another use of hyphenated analytical technique, capillary zone electrophoresis (CZE) connected to ultraviolet (UV) detector was also used for sensitive analysis of rhEPO at low levels (2000 IU) in the presence of large amount of human serum albumin (HSA). Analysis of rhEPO was achieved by the use of the electrokinetic injection (EI) with discontinuous buffers. Phosphate buffer was used as BGE with metal ions as additive. The proposed method can be used for the estimation of large number of quality control rhEPO samples in a short period.

  2. An integrated platform for directly widely-targeted quantitative analysis of feces part I: Platform configuration and method validation.

    Science.gov (United States)

    Song, Yuelin; Song, Qingqing; Li, Jun; Zheng, Jiao; Li, Chun; Zhang, Yuan; Zhang, Lingling; Jiang, Yong; Tu, Pengfei

    2016-07-01

    Direct analysis is of great importance to understand the real chemical profile of a given sample, notably biological materials, because either chemical degradation or diverse errors and uncertainties might be resulted from sophisticated protocols. In comparison with biofluids, it is still challenging for direct analysis of solid biological samples using high performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Herein, a new analytical platform was configured by online hyphenating pressurized liquid extraction (PLE), turbulent flow chromatography (TFC), and LC-MS/MS. A facile, but robust PLE module was constructed based on the phenomenon that noticeable back-pressure can be generated during rapid fluid passing through a narrow tube. TFC column that is advantageous at extracting low molecular analytes from rushing fluid was employed to link at the outlet of the PLE module to capture constituents-of-interest. An electronic 6-port/2-position valve was introduced between TFC column and LC-MS/MS to fragment each measurement into extraction and elution phases, whereas LC-MS/MS took the charge of analyte separation and monitoring. As a proof of concept, simultaneous determination of 24 endogenous substances including eighteen steroids, five eicosanoids, and one porphyrin in feces was carried out in this paper. Method validation assays demonstrated the analytical platform to be qualified for directly simultaneous measurement of diverse endogenous analytes in fecal matrices. Application of this integrated platform on homolog-focused profiling of feces is discussed in a companion paper. PMID:27268518

  3. Liquid-liquid extraction in flow analysis: A critical review

    International Nuclear Information System (INIS)

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

  4. Advancements in waste water characterization through NMR spectroscopy: review.

    Science.gov (United States)

    Alves Filho, Elenilson G; Alexandre e Silva, Lorena M; Ferreira, Antonio G

    2015-09-01

    There are numerous organic pollutants that lead to several types of ecosystem damage and threaten human health. Wastewater treatment plants are responsible for the removal of natural and anthropogenic pollutants from the sewage, and because of this function, they play an important role in the protection of human health and the environment. Nuclear magnetic resonance (NMR) has proven to be a valuable analytical tool as a result of its versatility in characterizing both overall chemical composition as well as individual species in a wide range of mixtures. In addition, NMR can provide physical information (rigidity, dynamics, etc.) as well as permit in depth quantification. Hyphenation with other techniques such as liquid chromatography, solid phase extraction and mass spectrometry creates unprecedented capabilities for the identification of novel and unknown chemical species. Thus, NMR is widely used in the study of different components of wastewater, such as complex organic matter (fulvic and humic acids), sludge and wastewater. This review article summarizes the NMR spectroscopy methods applied in studies of organic pollutants from wastewater to provide an exhaustive review of the literature as well as a guide for readers interested in this topic. PMID:25280056

  5. Determination of Noncovalent Binding Using a Continuous Stirred Tank Reactor as a Flow Injection Device Coupled to Electrospray Ionization Mass Spectrometry

    Science.gov (United States)

    Santos, Inês C.; Waybright, Veronica B.; Fan, Hui; Ramirez, Sabra; Mesquita, Raquel B. R.; Rangel, António O. S. S.; Fryčák, Petr; Schug, Kevin A.

    2015-07-01

    Described is a new method based on the concept of controlled band dispersion, achieved by hyphenating flow injection analysis with ESI-MS for noncovalent binding determinations. A continuous stirred tank reactor (CSTR) was used as a FIA device for exponential dilution of an equimolar host-guest solution over time. The data obtained was treated for the noncovalent binding determination using an equimolar binding model. Dissociation constants between vancomycin and Ac-Lys(Ac)-Ala-Ala-OH peptide stereoisomers were determined using both the positive and negative ionization modes. The results obtained for Ac- L-Lys(Ac)- D-Ala- D-Ala (a model for a Gram-positive bacterial cell wall) binding were in reasonable agreement with literature values made by other mass spectrometry binding determination techniques. Also, the developed method allowed the determination of dissociation constants for vancomycin with Ac- L-Lys(Ac)- D-Ala- L-Ala, Ac- L-Lys(Ac)- L-Ala- D-Ala, and Ac- L-Lys(Ac)- L-Ala- L-Ala. Although some differences in measured binding affinities were noted using different ionization modes, the results of each determination were generally consistent. Differences are likely attributable to the influence of a pseudo-physiological ammonium acetate buffer solution on the formation of positively- and negatively-charged ionic complexes.

  6. A neuron-in-capillary platform for facile collection and mass spectrometric characterization of a secreted neuropeptide

    Science.gov (United States)

    Lee, Chang Young; Fan, Yi; Rubakhin, Stanislav S.; Yoon, Sook; Sweedler, Jonathan V.

    2016-06-01

    The integration of microfluidic devices—which efficiently handle small liquid volumes—with separations/mass spectrometry (MS) is an effective approach for profiling the neurochemistry occurring in selected neurons. Interfacing the microfluidic cell culture to the mass spectrometer is challenging because of geometric and scaling issues. Here we demonstrate the hyphenation of a neuron-in-capillary platform to a solid phase extraction device and off-line MS. A primary neuronal culture of Aplysia californica neurons was established directly inside a cylindrical polyimide capillary. The approach also uses a particle-embedded monolith to condition neuropeptide releasates collected from several Aplysia neurons cultured in the capillary, with the subsequent characterization of released peptides via MS. This system presents a number of advances compared to more traditional microfluidic devices fabricated with polydimethylsiloxane. These include low cost, easy access to cell culture, rigidity, ease of transport, and minimal fluid handling. The cylindrical geometry of the platform allows convenient interface with a wide range of analytical tools that utilize capillary columns.

  7. [E]motion in the Nineteenth Century: A Culture of Fidgets

    Directory of Open Access Journals (Sweden)

    Karen Chase

    2014-10-01

    Full Text Available I see the fidget as a neglected aspect of the sense of touch, which collects a range of suggestive imaginative movements and which opens towards a rereading of Dickens's construal of character, its relation to the self, and its social world. An affective swamping of personality repeatedly overwhelms the barriers of personality. A tic, a flick, an insult, a plea, a joke, a contortion, a wink, a tickle, a prod - such fidgets lead an active life in the novels. They often reflect the friction of inter-subjectivity, but also the abrasions between character and the universe of objects. The twittering of a Miss Flite in 'Bleak House', Bradley Headstone's physical eruptions of rage, Mr F's Aunt's proleptic warnings and Flora Finching's galloping tale-telling in 'Little Dorrit', the handiwork of Uriah Heep in 'David Copperfield', the insuppressible hyphenated speech of Jingle in 'Pickwick Papers' - these are radiant instances. My article looks to give the fidget its due and to initiate more scholarly conversation on the circle of issues that it generates: mind and body, subjects and objects, textual continuity and its disruptions.

  8. Gas Chromatography Coupled to Atmospheric Pressure Chemical Ionization FT-ICR Mass Spectrometry for Improvement of Data Reliability.

    Science.gov (United States)

    Schwemer, Theo; Rüger, Christopher P; Sklorz, Martin; Zimmermann, Ralf

    2015-12-15

    Atmospheric pressure chemical ionization (APCI) offers the advantage of molecular ion information with low fragmentation. Hyphenating APCI to gas chromatography (GC) and ultrahigh resolution mass spectrometry (FT-ICR MS) enables an improved characterization of complex mixtures. Data amounts acquired by this system are very huge, and existing peak picking algorithms are usually extremely time-consuming, if both gas chromatographic and ultrahigh resolution mass spectrometric data are concerned. Therefore, automatic routines are developed that are capable of handling these data sets and further allow the identification and removal of known ionization artifacts (e.g., water- and oxygen-adducts, demethylation, dehydrogenation, and decarboxylation). Furthermore, the data quality is enhanced by the prediction of an estimated retention index, which is calculated simply from exact mass data combined with a double bond equivalent correction. This retention index is used to identify mismatched elemental compositions. The approach was successfully tested for analysis of semivolatile components in heavy fuel oil and diesel fuel as well as primary combustion particles emitted by a ship diesel research engine. As a result, 10-28% of the detected compounds, mainly low abundant species, classically assigned by using only the mass spectrometric information, were identified as not valid and removed. Although GC separation is limited by the slow acquisition rate of the FT-ICR MS (<1 Hz), a database driven retention time comparison, as commonly used for low resolution GC/MS, can be applied for revealing isomeric information. PMID:26560682

  9. Forensic Mass Spectrometry

    Science.gov (United States)

    Hoffmann, William D.; Jackson, Glen P.

    2015-07-01

    Developments in forensic mass spectrometry tend to follow, rather than lead, the developments in other disciplines. Examples of techniques having forensic potential born independently of forensic applications include ambient ionization, imaging mass spectrometry, isotope ratio mass spectrometry, portable mass spectrometers, and hyphenated chromatography-mass spectrometry instruments, to name a few. Forensic science has the potential to benefit enormously from developments that are funded by other means, if only the infrastructure and personnel existed to adopt, validate, and implement the new technologies into casework. Perhaps one unique area in which forensic science is at the cutting edge is in the area of chemometrics and the determination of likelihood ratios for the evaluation of the weight of evidence. Such statistical techniques have been developed most extensively for ignitable-liquid residue analyses and isotope ratio analysis. This review attempts to capture the trends, motivating forces, and likely impact of developing areas of forensic mass spectrometry, with the caveat that none of this research is likely to have any real impact in the forensic community unless: (a) The instruments developed are turned into robust black boxes with red and green lights for positives and negatives, respectively, or (b) there are PhD graduates in the workforce who can help adopt these sophisticated techniques.

  10. Analytical Methods for Chemical and Sensory Characterization of Scent-Markings in Large Wild Mammals: A Review

    Directory of Open Access Journals (Sweden)

    Simone B. Soso

    2014-03-01

    Full Text Available In conjoining the disciplines of “ethology” and “chemistry” the field of “Ethochemistry” has been instituted. Ethochemistry is an effective tool in conservation efforts of endangered species and the understanding of behavioral patterns across all species. Chemical constituents of scent-markings have an important, yet poorly understood function in territoriality, reproduction, dominance, and impact on evolutionary biology, especially in large mammals. Particular attention has recently been focused on scent-marking analysis of great cats (Kalahari leopards (Panthera pardus, puma (Puma concolor snow leopard (Panthera uncia, African lions (Panthera leo, cheetahs (Acinonyx jubatus, and tigers (Panthera tigris for the purpose of conservation. Sensory analyses of scent-markings could address knowledge gaps in ethochemistry. The objective of this review is to summarize the current state-of-the art of both the chemical and sensory analyses of scent-markings in wild mammals. Specific focus is placed on sampling and sample preparation, chemical analysis, sensory analysis, and simultaneous chemical and sensory analyses. Constituents of exocrine and endocrine secretions have been most commonly studied with chromatography-based analytical separations. Odor analysis of scent-markings provides an insight into the animal’s sensory perception. A limited number of articles have been published in the area of sensory characterization of scent marks. Simultaneous chemical and sensory analyses with chromatography-olfactometry hyphenation could potentially aid conservation efforts by linking perceived odor, compounds responsible for odor, and resulting behavior.

  11. Colloidal transport of uranium in soil: Size fractionation and characterization by field-flow fractionation-multi-detection

    International Nuclear Information System (INIS)

    The aim of this study was to characterize colloids associated with uranium by using an on-line fractionation/multi-detection technique based on asymmetrical flow field-flow fractionation (As-Fl-FFF) hyphenated with UV detector, multi angle laser light scattering (MALLS) and inductively coupling plasma-mass spectrometry (ICP-MS). Moreover, thanks to the As-Fl-FFF, the different colloidal fractions were collected and characterized by a total organic carbon analyzer (TOC). Thus it is possible to determine the nature (organic or inorganic colloids), molar mass, size (gyration and hydrodynamic radii) and quantitative uranium distribution over the whole colloidal phase. In the case of the site studied, two populations are highlighted. The first population corresponds to humic-like substances with a molar mass of (1500 ± 300) g mol-1 and a hydrodynamic diameter of (2. 0 ± 0. 2) nm. The second one has been identified as a mix of carbonated nano-particles or clays with organic particles (aggregates and/or coating of the inorganic particles) with a size range hydrodynamic diameter between 30 and 450 nm. Each population is implied in the colloidal transport of uranium: maximum 1% of the uranium content in soil leachate is transported by the colloids in the site studied, according to the depth in the soil. Indeed, humic substances are the main responsible of this transport in sub-surface conditions whereas nano-particles drive the phenomenon in depth conditions. (authors)

  12. Benefits of high resolution IC-ICP-MS for the routine analysis of inorganic and organic arsenic species in food products of marine and terrestrial origin

    Energy Technology Data Exchange (ETDEWEB)

    Kohlmeyer, Ute; Jantzen, Eckard; Kuballa, Juergen; Jakubik, Sandra [GALAB Laboratories, Max-Planck-Str. 1, 21502, Geesthacht (Germany)

    2003-09-01

    A recently developed and validated method for simultaneous determination of 17 inorganic and organic arsenic compounds in marine biota has been successfully applied to routine analysis of different food products, including fish, shellfish, edible algae, rice, and other types of grain. During one year, approximately 250 food samples were analyzed, mostly fish and rice. Long-term stability and robustness of the system was observed and reproducible results for certified reference materials were ensured by means of control charts. The separation was performed by ion-pair chromatography on an anion-exchange column to separate anionic, neutral, and cationic arsenic species in one chromatographic run. Hyphenation to ICP-MS allowed element-specific and sensitive detection of the different arsenic species with a detection limit as low as 8 ng As L{sup -1}in the sample extract, which is equivalent to 2 ng As g {sup -1} in the original sample. Special emphasis was laid on the analysis of marine algae and rice samples. These food types can contain elevated levels of the very toxic inorganic arsenic species (up to 90% in rice) and therefore are the focus of interest in the food industry. In marine algae, inorganic arsenic was mainly present as arsenate whereas in rice arsenite predominated. (orig.)

  13. Tracing gadolinium-based contrast agents from surface water to drinking water by means of speciation analysis.

    Science.gov (United States)

    Birka, Marvin; Wehe, Christoph A; Hachmöller, Oliver; Sperling, Michael; Karst, Uwe

    2016-04-01

    In recent decades, a significant amount of anthropogenic gadolinium has been released into the environment as a result of the broad application of contrast agents for magnetic resonance imaging (MRI). Since this anthropogenic gadolinium anomaly has also been detected in drinking water, it has become necessary to investigate the possible effect of drinking water purification on these highly polar microcontaminats. Therefore, a novel highly sensitive method for speciation analysis of gadolinium is presented. For that purpose, the hyphenation of hydrophilic interaction liquid chromatography (HILIC) and inductively coupled plasma-mass spectrometry (ICP-MS) was employed. In order to enhance the detection power, sample introduction was carried out by ultrasonic nebulization. In combination with a novel HILIC method using a diol-based stationary phase, it was possible to achieve superior limits of detection for frequently applied gadolinium-based contrast agents below 20pmol/L. With this method, the contrast agents Gd-DTPA, Gd-DOTA and Gd-BT-DO3A were determined in concentrations up to 159pmol/L in samples from several waterworks in a densely populated region of Germany alongside the river Ruhr as well as from a waterworks near a catchment lake. Thereby, the direct impact of anthropogenic gadolinium species being present in the surface water on the amount of anthropogenic gadolinium in drinking water was shown. There was no evidence for the degradation of contrast agents, the release of Gd(3+) or the presence of further Gd species. PMID:26931429

  14. An introduction to natural products isolation.

    Science.gov (United States)

    Sarker, Satyajit D; Nahar, Lutfun

    2012-01-01

    Natural products, well known for unique chemical diversity and bioactivity, have continued to offer templates for the development of novel scaffolds of drugs. With the remarkable developments in the areas of separation science, spectroscopic techniques, microplate-based ultrasensitive in vitro assays and high-throughput screening (HTS) technologies, natural products research has gained momentum in recent years. The pre-isolation analyses of crude extracts or fraction from different natural matrices, isolation, online detection and dereplication of natural products, studies on chemotaxonomy and biosynthesis, chemical finger-printing, quality control of herbal products, and metabolomic studies have now become much easier than ever before because of the availability of a number of modern sophisticated hyphenated techniques, e.g., GC-MS, LC-PDA, LC-MS, LC-FTIR, LC-NMR, LC-NMR-MS, and CE-MS. This introductory chapter presents a general overview of the processes involved in natural products research, starting from extraction and isolation to elucidation of the structures of purified natural products and their bioactivity. PMID:22367891

  15. Anionic metabolite profiling by capillary electrophoresis-mass spectrometry using a noncovalent polymeric coating. Orange juice and wine as case studies.

    Science.gov (United States)

    Acunha, Tanize; Simó, Carolina; Ibáñez, Clara; Gallardo, Alberto; Cifuentes, Alejandro

    2016-01-01

    In several metabolomic studies, it has already been demonstrated that capillary electrophoresis hyphenated to mass spectrometry (CE-MS) can detect an important group of highly polar and ionized metabolites that are overseen by techniques such as NMR, LC-MS and GC-MS, providing complementary information. In this work, we present a strategy for anionic metabolite profiling by CE-MS using a cationic capillary coating. The polymer, abbreviated as PTH, is composed of a poly-(N,N,N',N'-tetraethyldiethylenetriamine, N-(2-hydroxypropyl) methacrylamide, TEDETAMA-co-HPMA (50:50) copolymer. A CE-MS method based on PTH-coating was optimized for the analysis of a group of 16 standard anionic metabolites. Separation was achieved within 12min, with high separation efficiency (up to 92,000 theoretical plates per meter), and good repeatability, namely, relative standard deviation values for migration times and peak areas were below 0.2 and 2.1%, respectively. The optimized method allowed the detection of 87 metabolites in orange juice and 142 metabolites in red wine, demonstrating the good possibilities of this strategy for metabolomic applications. PMID:26296988

  16. Mass spectrometric analysis of pharmaceutical adulterants in products labeled as botanical dietary supplements or herbal remedies: a review.

    Science.gov (United States)

    Vaclavik, Lukas; Krynitsky, Alexander J; Rader, Jeanne I

    2014-11-01

    The increased availability and use of botanical dietary supplements and herbal remedies among consumers has been accompanied by an increased frequency of adulteration of these products with synthetic pharmaceuticals. Unscrupulous producers may add drugs and analogues of various classes, such as phosphodiesterase type 5 (PDE-5) inhibitors, weight loss, hypoglycemic, antihypertensive and anti-inflammatory agents, or anabolic steroids, to develop or intensify biological effects of dietary supplements or herbal remedies. The presence of such adulterated products in the marketplace is a worldwide problem and their consumption poses health risks to consumers. Analytical methods that allow rapid and reliable testing of dietary supplements for the presence of synthetic drugs are needed to address such fraudulent practices. Mass spectrometry (MS) and hyphenated techniques such as liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS) have become primary tools in this endeavor. The present review critically assesses the role and summarizes the applications of MS in the analysis of pharmaceutical adulterants in botanical dietary supplements and herbal remedies. The uses of MS techniques in detection, confirmation, and quantification of known pharmaceutical adulterants as well as in screening for and structure elucidation of unexpected adulterants and novel designer drugs are discussed. PMID:25270866

  17. Real Time Monitoring of Containerless Microreactions in Acoustically Levitated Droplets via Ambient Ionization Mass Spectrometry.

    Science.gov (United States)

    Crawford, Elizabeth A; Esen, Cemal; Volmer, Dietrich A

    2016-09-01

    Direct in-droplet (in stillo) microreaction monitoring using acoustically levitated micro droplets has been achieved by combining acoustic (ultrasonic) levitation for the first time with real time ambient tandem mass spectrometry (MS/MS). The acoustic levitation and inherent mixing of microliter volumes of reactants (3 μL droplets), yielding total reaction volumes of 6 μL, supported monitoring the acid-catalyzed degradation reaction of erythromycin A. This reaction was chosen to demonstrate the proof-of-principle of directly monitoring in stillo microreactions via hyphenated acoustic levitation and ambient ionization mass spectrometry. The microreactions took place completely in stillo over 30, 60, and 120 s within the containerless stable central pressure node of an acoustic levitator, thus readily promoting reaction miniaturization. For the evaluation of the miniaturized in stillo reactions, the degradation reactions were also carried out in vials (in vitro) with a total reaction volume of 400 μL. The reacted in vitro mixtures (6 μL total) were similarly introduced into the acoustic levitator prior to ambient ionization MS/MS analysis. The in stillo miniaturized reactions provided immediate real-time snap-shots of the degradation process for more accurate reaction monitoring and used a fraction of the reactants, while the larger scale in vitro reactions only yielded general reaction information. PMID:27505037

  18. Multivariate classification of pigments and inks using combined Raman spectroscopy and LIBS.

    Science.gov (United States)

    Hoehse, Marek; Paul, Andrea; Gornushkin, Igor; Panne, Ulrich

    2012-02-01

    The authenticity of objects and artifacts is often the focus of forensic analytic chemistry. In document fraud cases, the most important objective is to determine the origin of a particular ink. Here, we introduce a new approach which utilizes the combination of two analytical methods, namely Raman spectroscopy and laser-induced breakdown spectroscopy (LIBS). The methods provide complementary information on both molecular and elemental composition of samples. The potential of this hyphenation of spectroscopic methods is demonstrated for ten blue and black ink samples on white paper. LIBS and Raman spectra from different inks were fused into a single data matrix, and the number of different groups of inks was determined through multivariate analysis, i.e., principal component analysis, soft independent modelling of class analogy, partial least-squares discriminant analysis, and support vector machine. In all cases, the results obtained with the combined LIBS and Raman spectra were found to be superior to those obtained with the individual Raman or LIBS data sets. PMID:21845528

  19. Analytical methods for the endocrine disruptor compounds determination in environmental water samples.

    Science.gov (United States)

    Locatelli, Marcello; Sciascia, Francesco; Cifelli, Roberta; Malatesta, Luciano; Bruni, Pantaleone; Croce, Fausto

    2016-02-19

    The potential risk of exposure to different xenobiotics, which can modulate the endocrine system and represent a treat for the wellness of an increasing number of people, has recently drawn the attention of international environmental and health agencies. Several agents, characterized by structural diversity, may interfer with the normal endocrine functions that regulate cell growth, homeostasis and development. Substances such as pesticides, herbicides, plasticizers, metals, etc. having endocrine activity (EDCs) are used in agriculture and industry and are also used as drugs for humans and animals. A difficulty in the analytical determination of these substances is the complexity of the matrix in which they are present. In fact, the samples most frequently analyzed consist of groundwater and surface water, including influent and effluent of wastewater treatment plants and drinking water. In this review, several sample pretreatment protocols, assays and different instrumental techniques recently used in the EDCs determination have been considered. This review concludes with a paragraph in which the most recent hyphenated-instrument techniques are treated, highlighting their sensitivity and selectivity for the analyses of environmental water samples. PMID:26805600

  20. HPTLC-aptastaining – Innovative protein detection system for high-performance thin-layer chromatography

    Science.gov (United States)

    Morschheuser, Lena; Wessels, Hauke; Pille, Christina; Fischer, Judith; Hünniger, Tim; Fischer, Markus; Paschke-Kratzin, Angelika; Rohn, Sascha

    2016-05-01

    Protein analysis using high-performance thin-layer chromatography (HPTLC) is not commonly used but can complement traditional electrophoretic and mass spectrometric approaches in a unique way. Due to various detection protocols and possibilities for hyphenation, HPTLC protein analysis is a promising alternative for e.g., investigating posttranslational modifications. This study exemplarily focused on the investigation of lysozyme, an enzyme which is occurring in eggs and technologically added to foods and beverages such as wine. The detection of lysozyme is mandatory, as it might trigger allergenic reactions in sensitive individuals. To underline the advantages of HPTLC in protein analysis, the development of innovative, highly specific staining protocols leads to improved sensitivity for protein detection on HPTLC plates in comparison to universal protein derivatization reagents. This study aimed at developing a detection methodology for HPTLC separated proteins using aptamers. Due to their affinity and specificity towards a wide range of targets, an aptamer based staining procedure on HPTLC (HPTLC-aptastaining) will enable manifold analytical possibilities. Besides the proof of its applicability for the very first time, (i) aptamer-based staining of proteins is applicable on different stationary phase materials and (ii) furthermore, it can be used as an approach for a semi-quantitative estimation of protein concentrations.

  1. Genuineness assessment of mandarin essential oils employing gas chromatography-combustion-isotope ratio MS (GC-C-IRMS).

    Science.gov (United States)

    Schipilliti, Luisa; Tranchida, Peter Quinto; Sciarrone, Danilo; Russo, Marina; Dugo, Paola; Dugo, Giovanni; Mondello, Luigi

    2010-03-01

    Cold-pressed mandarin essential oils are products of great economic importance in many parts of the world and are used in perfumery, as well as in food products. Reconstituted mandarin oils are easy to find on the market; useful information on essential oil authenticity, quality, extraction technique, geographic origin and biogenesis can be attained through high-resolution GC of the volatile fraction, or enantioselective GC, using different chiral stationary phases. Stable isotope ratio analysis has gained considerable interest for the unveiling of citrus oil adulteration, detecting small differences in the isotopic carbon composition and providing plenty of information concerning the discrimination among products of different geographical origin and the adulteration of natural essential oils with synthetic or natural compounds. In the present research, the authenticity of several mandarin essential oils was assessed through the employment of GC hyphenated to isotope ratio MS, conventional GC flame ionization detector, enantioselective GC and HPLC. Commercial mandarin oils and industrial natural (declared as such) mandarin essential oils, characterized by different harvest periods and geographic origins, were subjected to analysis. The results attained were compared with those of genuine cold-pressed Italian mandarin oils, obtained during the 2008-2009 harvest season. PMID:20112303

  2. Selenium Metabolism in Cancer Cells: The Combined Application of XAS and XFM Techniques to the Problem of Selenium Speciation in Biological Systems

    Directory of Open Access Journals (Sweden)

    Hugh H. Harris

    2013-05-01

    Full Text Available Determining the speciation of selenium in vivo is crucial to understanding the biological activity of this essential element, which is a popular dietary supplement due to its anti-cancer properties. Hyphenated techniques that combine separation and detection methods are traditionally and effectively used in selenium speciation analysis, but require extensive sample preparation that may affect speciation. Synchrotron-based X-ray absorption and fluorescence techniques offer an alternative approach to selenium speciation analysis that requires minimal sample preparation. We present a brief summary of some key HPLC-ICP-MS and ESI-MS/MS studies of the speciation of selenium in cells and rat tissues. We review the results of a top-down approach to selenium speciation in human lung cancer cells that aims to link the speciation and distribution of selenium to its biological activity using a combination of X-ray absorption spectroscopy (XAS and X-ray fluorescence microscopy (XFM. The results of this approach highlight the distinct fates of selenomethionine, methylselenocysteine and selenite in terms of their speciation and distribution within cells: organic selenium metabolites were widely distributed throughout the cells, whereas inorganic selenium metabolites were compartmentalized and associated with copper. New data from the XFM mapping of electrophoretically-separated cell lysates show the distribution of selenium in the proteins of selenomethionine-treated cells. Future applications of this top-down approach are discussed.

  3. Measurement of isotope ratios on transient signals by MC-ICP-MS

    International Nuclear Information System (INIS)

    Precise and accurate isotope ratio measurements are an important task in many applications such as isotope-dilution mass spectrometry, bioavailability studies, or the determination of isotope variations in geological or nuclear samples. The technique of MC-ICP-MS has attracted much attention because it permits the precise measurement of isotope compositions for a wide range of elements combined with excellent detection limits due to high ionisation efficiencies. However, the results are based mainly on measurements using continuous sample introduction. In the present study the determination of isotope ratios on various transient signals with a time duration of 30 to 60 s has been achieved by coupling high-performance liquid chromatography to a multicollector inductively coupled plasma mass spectrometer. In order to investigate the origin of ratio drifts across the transient signals for this hyphenated technique, measurements with the same standard solutions were also carried out using a flow-injection device for sample introduction. As a result of this application it could be concluded that the main source of the bias in the measured isotope ratios is within the ICP-MS instead of fractionation effects on the chromatographic column material. Preliminary studies on short transient signals of gaseous samples (dry plasma) showed a reverse fractionation effect compared with wet plasma conditions (flow injection and HPLC). (orig.)

  4. Gas chromatography/plasma spectrometry - an important analytical tool for elemental speciation studies

    International Nuclear Information System (INIS)

    In this review, a full discussion and update of the state-of-the-art of gas chromatography (GC) coupled to all known plasma spectrometers is presented. A brief introductive discussion of the advantages and disadvantages of GC-plasma interfaces, as well as types of plasmas and mass spectrometers, is given. The plasma-based techniques covered include inductively coupled plasma mass spectrometry (ICP-MS) microwave-induced plasma optical emission spectrometry (MIP-OES), and inductively coupled plasma optical emission spectrometry (ICP-OES). Also, different variants of plasma sources, such as low power plasmas and glow discharge (GD) sources, are described and compared with respect to their capabilities in elemental speciation. Recent advances and alternative mass analyzers (collision/reaction cell; time-of-flight; double-focusing sector field) are also mentioned. Different aspects of the GC-plasma coupling are discussed with particular attention to the applications of these hyphenated techniques to the analysis of elemental species. Additionally, classical and modern sample preparation methods, including extraction and/or preconcentration and derivatization reactions, are presented and evaluated

  5. Uptake and localization of nutritive and potentially toxic minerals in ectomycorrhizas of forest trees; Aufnahme und Verbleib von Naehr- und Schadelementen in Ektomykorrhizen in Abhaengigkeit von den umgebenden Bodenfaktoren

    Energy Technology Data Exchange (ETDEWEB)

    Kottke, I.; Oberwinkler, F. [Tuebingen Univ. (Germany). Botanisches Inst.

    1992-05-01

    Mycorrhizas of Norway spruce were analysed by means of electron energy loss spectroscopy (EELS/ESI) on TEM 902 ZEISS in respect to distribution of aluminium, calcium, phosphorus and cadmium after exposure of the objects to enhanced concentrations of the elements. Exclusion mechanism in mycorrhizas for aluminium and other toxic elements can be derived from the results and reveal buffering capacity for noxic soil ions attained by mycorrhization. Polyphosphates in hyphal vacuoles are shown to be important sites for detoxification. The precise localization of elements yields valuable information not otherwise attainable. (orig.) With 20 figs., 61 refs. [Deutsch] Mykorrhizen der Fichte wurden mit Hilfe der Elektronen-Energieverlust-Analyse am TEM 902 ZEISS bezueglich der zellulaeren Verteilung von Aluminium, Calcium, Phosphor, Stickstoff und Cadmium untersucht, nachdem die Objekte erhoehten Konzentrationen der jeweiligen Elemente ausgesetzt worden waren. Aus den Untersuchungsergebnissen lassen sich verschiedene Ausschlussmechanismen potentiell toxischer Elemente ableiten. Die Polyphosphatgrana in den Vakuolen der Hyphen dienen offensichtlich nicht nur der Phosphatspeicherung sondern auch der Entsorgung. Die Verteilungsmuster belegen den Informationsgewinn durch eine so genaue Elementlokalisation und zeigen die puffernde Wirkung der Mykorrhizierung gegen Ionenstress im Boden. (orig.) With 20 figs., 61 refs.

  6. Capillary electrokinetic chromatography of insulin and related synthetic analogues.

    Science.gov (United States)

    Ortner, K; Buchberger, W; Himmelsbach, M

    2009-04-01

    With the implementation of recombinant DNA technology in the pharmaceutical industry, some synthetic insulins have been developed in order to improve the therapy of diabetes. These analogues differ only slightly in the amino acid sequence, therefore displaying a great challenge for analytical chemistry. Within the work presented in this paper, capillary zone electrophoresis (CZE), micellar electrokinetic chromatography (MEKC) with sodium dodecylsulphate (SDS) as micelle-forming agent, and microemulsion electrokinetic chromatography (MEEKC) with microemulsions consisting of SDS, n-octane and 1-butanol were investigated for the separation of human insulin and five synthetic analogues. Best results were achieved with a solvent-modified MEKC system consisting of 100mM sodium dodecyl sulphate and 15% acetonitrile in 10mM borate buffer (pH 9.2). A similar system based on perfluorooctanoic acid as micelle-forming agent in ammonium acetate (pH 9.2) was successfully employed for the hyphenation with a quadrupole/time-of-flight mass spectrometer via a sheath-flow interface. In this case, detection limits at 10mg/L could be achieved. PMID:19027906

  7. Extracting numeric measurements and temporal coordinates from Japanese radiological reports

    Science.gov (United States)

    Imai, Takeshi; Onogi, Yuzo

    2004-04-01

    Medical records are written mainly, in natural language. The focus of this study is narrative radiological reports written in natural Japanese. These reports cannot be used for advanced retrieval, data mining, and so on, unless they are stored, using a structured format such as DICOM-SR. The goal is to structure narrative reports progressively, using natural language processing (NLP). Structure has many different levels, for example, DICOM-SR has three established levels -- basic text, enhanced and comprehensive. At the enhanced level, it is necessary to use numerical measurements and spatial & temporal coordinates. In this study, the wording used in the reports was first standardized, dictionaries were organized, and morphological analysis performed. Next, numerical measurements and temporal coordinates were extracted, and the objects to which they referred, analyzed. 10,000 CT and MR reports were separated into 82,122 sentences, and 34,269 of the 36,444 numerical descriptions were tagged. Periods, slashes, hyphens, and parentheses are ambiguously used in the description of enumerated lists, dates, image numbers, and anatomical names, as well as at the end of sentences; to resolve this ambiguity, descriptions were processed, according to the order -- date, size, unit, enumerated list, and abbreviation -- then, the tagged reports were separated into sentences.

  8. Sulfur analysis by inductively coupled plasma-mass spectrometry: A review

    International Nuclear Information System (INIS)

    In recent years the number of applications of sulfur (S) analysis using inductively coupled plasma mass spectrometry (ICP-MS) as detector has increased significantly. In this article we describe in some depth the application of ICP-MS for S analysis with emphasis placed on the sulfur-specific detection by hyphenated techniques such as LC, GC, CE and LA coupled on-line to ICP-MS. The different approaches available for sulfur isotope ratio measurements by ICP-MS are also detailed. Particular attention has been paid to the quantification of peptides/proteins and the analysis of metallopeptides/metalloproteins via sulfur by LC–ICP-MS. Likewise, the speciation analysis of metal-based pharmaceuticals and metallodrugs and non-metal selective detection of pharmaceuticals via S are highlighted. Labeling procedures for metabolic applications are also included. Finally, the measurement of natural variations in S isotope composition with multicollector ICP-MS instruments is also covered in this review. - Highlights: • Emphasis placed on the sulfur-specific detection by chromatographic techniques coupled on-line to ICP-MS. • Different instrumental approaches available for sulfur measurements by ICP-MS. • Quantification of proteins and the analysis of metalloproteins via sulfur by LC-ICP-MS. • Labelling procedures for metabolic applications are also included. • The measurement of natural variations in S isotope composition with multicollector ICP-MS

  9. Evidence of different stoichiometries for the limiting carbonate complexes of lanthanides(3)

    International Nuclear Information System (INIS)

    Two stoichiometries have been proposed by different laboratories to interpret measurements on the limiting carbonate complexes of An3+ and Ln3+ cations. The study of the solubility of double carbonates (AlkLn(CO3)2,xH2O) in concentrated carbonate solutions at room temperature and high ionic strengths has shown that on the one hand the lightest lanthanides (La and Nd) form Ln(CO3)45- whereas the heaviest (Eu and Dy) form Ln(CO3)33- in the studied chemical conditions, and on the other hand, that the kinetics of precipitation of double carbonates depends on the alkali metal and the lanthanide ions. The existence of two stoichiometries for the limiting carbonate complexes was confirmed by capillary electrophoresis hyphenated to an inductively coupled plasma mass spectrometer (CE-ICP-MS), used to extend the study to the whole series of lanthanides (except Ce, Pm and Yb). Two behaviours have been put forward comparing the electrophoretic mobilities: La to Tb form Ln(CO3)45- while Dy to Lu form Ln(CO3)33-. Measurements by time resolved laser fluorescence spectroscopy (TRLFS) on Eu(III) indicate small variations of the geometry of Eu(CO3)33- complex, specially with Cs+. Although analogies are currently used among the 4f-block trivalent elements, different aqueous speciations are evidenced in concentrated carbonate solutions across the lanthanide series. (author)

  10. Characterization and Quantification of Compounds in the Hydroalcoholic Extract of the Leaves from Terminalia catappa Linn. (Combretaceae and Their Mutagenic Activity

    Directory of Open Access Journals (Sweden)

    Francisco José Mininel

    2014-01-01

    Full Text Available Terminalia is a genus of Combretaceous plants widely distributed in tropical and subtropical regions. Thus, the aim of this study was to quantify the majority compounds of the hydroalcoholic extract (7 : 3, v/v of the leaves from T. catappa by HPLC-PDA, chemically characterize by hyphenated techniques (HPLC-ESI-IT-MSn and NMR, and evaluate its mutagenic activity by the Salmonella/microsome assay on S. typhimurium strains TA98, TA97a, TA100, and TA102. The quantification of analytes was performed using an external calibration standard. Punicalagin is the most abundant polyphenol found in the leaves. The presence of this compound as a mixture of anomers was confirmed using HPLC-PDA and 1H and 13C NMR. Mutagenic activity was observed in strains TA100 and TA97a. As the extract is a complex mixture of punicalagin, its derivatives, and several other compounds, the observed mutagenicity may be explained in part by possible synergistic interaction between the compounds present in the extract. These studies show that mutagenic activity of T. catappa in the Ames test can only be observed when measured at high concentrations. However, considering the mutagenic effects observed for T. catappa, this plant should be used cautiously for medicinal purposes.

  11. Correlations between dioxin-like and indicators PCBs: Potential consequences for environmental studies involving fish or sediment

    International Nuclear Information System (INIS)

    Among the numerous PCB congeners, most of the dioxin-like PCBs (DL-PCBs) need to be characterized by hyphenated techniques. It has been shown in several instances that these congeners are well related to the total PCB content in fish. We examined datasets collected mainly in France, on freshwater and marine fish and sediments. A statistical model linking DL- and indicator PCBs was developed for a dataset composed of freshwater fishes, and proved to predict well DL-PCBs from indicator PCBs in all other fish sets, including marine ones. Type II error rates remained low in almost all fish sets. A similar correlation was observed in sediments. Non-dioxin-like PCBs elicit various adverse effects and represent 95% of the total PCBs. A European guideline for them is needed; the correlation between DL- and indicator PCBs could help develop this standard in the future. - Dioxin-like PCBs in fish and maybe sediments are rather well predicted by indicator PCBs.

  12. Elemental speciation of neptunium in ultra trace amount ranges; Elementspeziation von Neptunium im Ultraspurenbereich

    Energy Technology Data Exchange (ETDEWEB)

    Stoebener, Nils

    2013-06-25

    In the presented work, the detection of the isotope Np-237 with resonance ionization mass spectrometry (RIMS) was developed and optimized. In RIMS, sample atoms are excited and ionized with laser radiation in several, resonant steps and are subsequently detected by a mass spectrometer. Energy levels suitable for the excitation and ionization of Np-237 were identified using resonance ionization spectroscopy (RIS). With RIS, more than 300 previously unknown electronic states and autoionizing resonances of Np-237 were identified. Using in-source-RIMS, a limit of detection of 9E+5 atoms was demonstrated for the isotope. The mobility of Np in the environment strongly depends on its elemental speciation. Therefore, safety assessments of proposed nuclear waste repositories require analytical methods for the detection of Np species. CE (capillary electrophoresis) was hyphenated to ICP-MS (inductively coupled plasma mass spectrometry) to examine the distribution of the Np redox species Np(IV) and Np(V), which was possible at Np concentrations as low as 1E-9 mol/L. The method was used to study the interaction of the element with Opalinus Clay at varying conditions. CE-ICP-MS revealed, that under the presence of Fe(II), Np(V) is reduced to Np(IV), which is sorbed onto the clay. This leads to a higher overall Np sorption.

  13. Complex mixture analysis of environmentally important samples utilizing GC/Matrix isolation-FTIR-MS

    International Nuclear Information System (INIS)

    Gas chromatography/matrix isolation Fourier transform infrared spectroscopy-mass spectroscopy (GC/MI-FTIR-MS) is a highly sensitive and specific hyphenated technique that combines the capabilities of capillary gas chromatography for separating components of complex mixtures with the high sensitivity and specificity of both matrix isolation infrared and mass spectrometric detection. Research intended to extend application of this methodology to analysis of a variety of environmental mixtures will be described. The authors instrument utilizes a Hewlett-Packard 58900 GC with a 40:40:20 three way splitter to the infrared detector, mass selective detector and flame ionization detector, respectively. The FTIR used is a Mattson Cryolect 4800, while the MS is a Hewlett-Packard 5970B MSD. Their most recent results from analysis of mixtures containing picogram quantities of such environmentally important materials as PAH's and chlorinated pesticides will be presented. These mixtures can be chromatography separated and analyzed at the low-nanogram to several hundred picogram level. The results presented will include both MS and IR spectra, MS and IR reconstructed chromatograms as well as FID traces. The results of MS and IR database searches will also be shown

  14. Analytical methods for chemical and sensory characterization of scent-markings in large wild mammals: a review.

    Science.gov (United States)

    Soso, Simone B; Koziel, Jacek A; Johnson, Anna; Lee, Young Jin; Fairbanks, W Sue

    2014-01-01

    In conjoining the disciplines of "ethology" and "chemistry" the field of "Ethochemistry" has been instituted. Ethochemistry is an effective tool in conservation efforts of endangered species and the understanding of behavioral patterns across all species. Chemical constituents of scent-markings have an important, yet poorly understood function in territoriality, reproduction, dominance, and impact on evolutionary biology, especially in large mammals. Particular attention has recently been focused on scent-marking analysis of great cats (Kalahari leopards (Panthera pardus), puma (Puma concolor) snow leopard (Panthera uncia), African lions (Panthera leo), cheetahs (Acinonyx jubatus), and tigers (Panthera tigris)) for the purpose of conservation. Sensory analyses of scent-markings could address knowledge gaps in ethochemistry. The objective of this review is to summarize the current state-of-the art of both the chemical and sensory analyses of scent-markings in wild mammals. Specific focus is placed on sampling and sample preparation, chemical analysis, sensory analysis, and simultaneous chemical and sensory analyses. Constituents of exocrine and endocrine secretions have been most commonly studied with chromatography-based analytical separations. Odor analysis of scent-markings provides an insight into the animal's sensory perception. A limited number of articles have been published in the area of sensory characterization of scent marks. Simultaneous chemical and sensory analyses with chromatography-olfactometry hyphenation could potentially aid conservation efforts by linking perceived odor, compounds responsible for odor, and resulting behavior. PMID:24603639

  15. Solid phase microextraction and stir bar sorptive extraction for organotin compounds - a comparison (P9)

    International Nuclear Information System (INIS)

    Full text: Organotin compounds have been largely used in agricultural and industrial applications. Hyphenated techniques were developed for the sensitive and selective determination of such species. For this task GC has been coupled with atomic emission detection. Derivatization to transform the Sn-compounds into sufficiently volatile compounds was necessary and carried out using sodium tetrapropylborate. For sample preparation the application of solid phase microextraction (SPME) give recent advances in comparison to classical liquid-liquid extraction (LEE). A problem in the usage of SPME exists however in the small volume of the PDMS coating for enrichment the analytes. For improvement of both sample enrichment and extraction of the organotin compounds stir bar sorptive extraction (SBSE) was applied. It base on the application of stir bars coated with PDMS. Here the extraction yield is substantially higher. Aim of this study was to compare the capabilities of GC-AED in combination with SPME and SBSE. After optimization of the experimental parameters it was possible to reach detection limits in the pg / 1 - level. A comparison of both methods shows the expected results. By application of SBSE it was possible to increase the detection limits one order of magnitude. With SPME the reproducibility of the analytical results (in the 1 ng / 1 concentration range) was found to be between 10 and 15 %, it could be enhanced to 5-8 % by application of SBSE. These low limits of detection and the good reproducibility allowed the determination of organotin compounds according required regulations. Ref. 1 (author)

  16. PY-GC-MS applied to the identification of synthetic resins in Brazilian painting

    International Nuclear Information System (INIS)

    Works of art are appreciated for their material and immaterial value. Restoring objects of art is a delicate procedure, mostly due to the irreversibility of the interventions. Hence, it is recommended to study the chemical composition of the object to avoid errors. The premise for restoring or conserving these objects is their physical preservation, i.e., it is advisable to avoid sampling and, when necessary, samples must be minute. The analytical techniques that fulfill these requirements are limited. Mass spectrometry (MS) is a versatile technique due to its hyphenation possibilities. Recently, it has being employed in the identification of natural and synthetic resins in works of art. Electron ionization (EI) is a powerful method of molecular fragmentation employed in the detection of volatile organic compounds by mass spectrometry. In this work, two micrograms (μg) of sample from a Brazilian contemporary painting were analyzed by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) technique. A microfurnace-type pyrolyzer was coupled to a gas chromatograph, using a non-polar capillary column. The electron ionization was achieved applying 70 eV electron energy. This technique is suitable for the analysis of material from objects of art, being specific, accurate and requiring minimal sampling. The synthetic resin diallyl phthalate (DAP) was identified by the Py-GC/MS technique. (author)

  17. Immersed single-drop microextraction interfaced with sequential injection analysis for determination of Cr(VI) in natural waters by electrothermal-atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Single-drop microextraction (SDME) and sequential injection analysis have been hyphenated for ultratrace metal determination by Electrothermal-Atomic Absorption Spectrometry (ETAAS). The novel method was targeted on extraction of the Cr(VI)-APDC chelate and encompasses the potential of SDME as a miniaturized and virtually solvent-free preconcentration technique, the ability of sequential injection analysis to handle samples and the versatility of furnace autosamplers for introducing microliter samples in ETAAS. The variables influencing the microextraction of Cr(VI) onto an organic solvent drop, i.e., type of organic solvent, microextraction time, stirring rate of the sample solution, drop volume, immersion depth of the drop, salting-out effect, temperature of the sample, concentration of the complexing agent and pH of the sample solution were fully investigated. For a 5 and 20 min microextraction time, the preconcentration factors were 20 and 70, respectively. The detection limit was 0.02 μg/L of Cr(VI) and the repeatability expressed as relative standard deviation was 7%. The SDME-SIA-ETAAS technique was validated against BCR CRM 544 (lyophilized solution) and applied to ultrasensitive determination of Cr(VI) in natural waters

  18. Determination of tellurium by hydride generation with in situ trapping flame atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Matusiewicz, H.; Krawczyk, M. [Politechn Poznanska, Poznan (Poland)

    2007-03-15

    The analytical performance of coupled hydride generation - integrated atom trap (HG-IAT) atomizer flame atomic absorption spectrometry (FAAS) system was evaluated for determination of Te in reference material (GBW 07302 Stream Sediment), coal fly ash and garlic. Tellurium, using formation of H{sub 2}Te vapors, is atomized in air-acetylene flame-heated IAT. A new design HG-IAT-FAAS hyphenated technique that would exceed the operational capabilities of existing arrangernents (a water-cooled single silica tube, double-slotted quartz tube or an 'integrated trap') was investigated. An improvement in detection limit was achieved compared with using either of the above atom trapping techniques separately. The concentration detection limit, defined as 3 times the blank standard deviation (3{sigma}), was 0.9 ng mL{sup -1} for Te. For a 2 min in situ preconcentration time (sample volume of 2 mL), sensitivity enhancement compared to flame AAS, was 222 fold, using the hydride generation atom trapping technique. The sensitivity can be further improved by increasing the collection time. The precision, expressed as RSD, was 7.0% (n = 6) for Te. The accuracy of the method was verified using a certified reference material (GBW 07302 Stream Sediment) by aqueous standard calibration curves. The measured Te contents of the reference material was in agreement with the information value. The method was successfully applied to the determination of tellurium in coal fly ash and garlic.

  19. Analysis of multiple mycotoxins in beer employing (ultra)-high-resolution mass spectrometry.

    Science.gov (United States)

    Zachariasova, Milena; Cajka, Tomas; Godula, Michal; Malachova, Alexandra; Veprikova, Zdenka; Hajslova, Jana

    2010-11-30

    The objective of the presented study was to develop and optimize a simple, high-throughput method for the control of 32 mycotoxins (Fusarium and Alternaria toxins, aflatoxins, ergot alkaloids, ochratoxins, and sterigmatocystin) in beer. Due to the broad range of their physicochemical properties, the sample preparation step was simplified as much as possible to avoid analyte losses. The addition of acetonitrile to beer samples enabled precipitation of abundant matrix components. The clean-up efficiency was controlled by ambient mass spectrometry employing a direct analysis in real time (DART) ion source. For determination of analytes, ultra-high-performance liquid chromatography hyphenated with high-resolution mass spectrometry utilizing an orbitrap (U-HPLC-orbitrapMS) or time-of-flight (TOFMS) technology was used. Because of significantly better detection capabilities of the orbitrap technology, the U-HPLC-orbitrapMS method was chosen as a determinative step and fully validated. To compensate matrix effects, matrix-matched calibration was employed. The lowest calibration levels for most of the target mycotoxins ranged from 1 to 8  µg  L(-1) beer and the recoveries of analytes were in range from 86 to 124%. PMID:20973012

  20. Simultaneous determination of quinolones for veterinary use by high-performance liquid chromatography with electrochemical detection.

    Science.gov (United States)

    Rodríguez Cáceres, M I; Guiberteau Cabanillas, A; Galeano Díaz, T; Martínez Cañas, M A

    2010-02-01

    A selective method based on high-performance liquid chromatography with electrochemical detection (HPLC-ECD) has been developed to enable simultaneous determination of three fluoroquinolones (FQs), namely danofloxacin (DANO), difloxacin (DIFLO) and sarafloxacin (SARA). The fluoroquinolones are separated on a Novapack C-18 column and detected in a high sensitivity amperometric cell at a potential of +0.8 V. Solid-phase extraction was used for the extraction of the analytes in real samples. The range of concentration examined varied from 10 to 150 ng g(-1) for danofloxacin, from 25 to 100 ng g(-1) for sarafloxacin and from 50 to 315 ng g(-1) for difloxacin, respectively. The method presents detection limits under 10 ng g(-1) and recoveries around 90% for the three analytes have been obtained in the experiments with fortified samples. This HPLC-ECD approach can be useful in the routine analysis of antibacterial residues being less expensive and less complicated than other more powerful tools as hyphenated techniques. PMID:20042380

  1. Bioanalytical Applications of Fluorescence Line-Narrowing and Non-Line-Narrowing Spectroscopy Interfaced with Capillary Electrophoresis and High-Performance Liquid Chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Kenneth Paul Roberts

    2002-06-27

    Capillary electrophoresis (CE) and high-performance liquid chromatography (HPLC) are widely used analytical separation techniques with many applications in chemical, biochemical, and biomedical sciences. Conventional analyte identification in these techniques is based on retention/migration times of standards; requiring a high degree of reproducibility, availability of reliable standards, and absence of coelution. From this, several new information-rich detection methods (also known as hyphenated techniques) are being explored that would be capable of providing unambiguous on-line identification of separating analytes in CE and HPLC. As further discussed, a number of such on-line detection methods have shown considerable success, including Raman, nuclear magnetic resonance (NMR), mass spectrometry (MS), and fluorescence line-narrowing spectroscopy (FLNS). In this thesis, the feasibility and potential of combining the highly sensitive and selective laser-based detection method of FLNS with analytical separation techniques are discussed and presented. A summary of previously demonstrated FLNS detection interfaced with chromatography and electrophoresis is given, and recent results from on-line FLNS detection in CE (CE-FLNS), and the new combination of HPLC-FLNS, are shown.

  2. Instrument platforms for thin-layer chromatography.

    Science.gov (United States)

    Bernard-Savary, Pierre; Poole, Colin F

    2015-11-20

    High performance column and thin-layer chromatography are both instrumental techniques but differ in that column chromatography requires a fully integrated instrument platform with high pressure capability while for thin-layer chromatography separate devices are used for each unit operation, usually at or close to atmospheric pressure, and afford higher flexibility supporting on-line or off-line operation. The unit operations of thin-layer chromatography are defined as sample application, development and evaluation with derivatization as an optional step. The diversity of equipment for each operation contributes to the flexibility of analysis by thin-layer chromatography and supports manual, semi-automated or full-automation of the separation process. Instrument platforms are more than a convenience as they affect performance, repeatability, sample detectability, and time management. The current trend in thin-layer chromatography is to make the unit operations independent of the user so that analysts can perform other tasks while each step is performed. In addition, in thin-layer chromatography it is general practice to separate several samples simultaneously, and instrument platforms are required to accommodate this feature. In this article, we review contemporary instrumentation employed in thin-layer chromatography for sample application, development, derivatization, photodocumentation, densitometric evaluation, and hyphenation with spectroscopic detectors with an emphasis on the variety and performance of commercially available systems. Some suggestions for best practices and avoidance of common mistakes are included. PMID:26260842

  3. On time-distance curves for Pn waves in the Friuli earthquake of 6 May 1976

    Directory of Open Access Journals (Sweden)

    P. F. BIAGI

    1979-06-01

    Full Text Available Results obtained in the study of the arrival times of the Pn phase for
    the Friuli earthquake of 6 May 1976 (H = 20h00™15s,5; φ = 46° 16'30" N;

    En el artículo se presenta la noción de

  4. EDUCATIONAL RESEARCH: SOME BASIC CONCEPTS AND TERMINOLOGY

    Directory of Open Access Journals (Sweden)

    SONAL SHIVGUNDE

    2012-11-01

    Full Text Available Research is the orderly investigation of a subject matter for the purpose of adding to knowledge. Research can mean 're-search' implying that the subject matter is already known but, for one reason or another, needs to be studied again (Borg, W.R. and Gall, M.D. ,1989. Alternatively, the expression can be used without a hyphen and in this case it typically means investigating a new problem or phenomenon. Within the realm of educational planning, many things are always changing: the structure of the education system, curriculum and textbooks, modes of teaching, methods of teacher training, the amount and type of provisions to schools such as science laboratories, textbooks, furniture, classroom supplies, and so on. These changes may lead to an improvement, or a worsening, in the quality of an educational system (Hopkins, 1990. Sometimes they may result in no impact upon quality - in which case major government expenditures on such changes have been wasted. The educational planner working within this kind of environment must be able to undertake assessments of the effects of major changes and then provide policy advice that will consolidate and extend the post productive courses of action, and also intercept and terminate existing practices that are shown to be damaging and wasteful.

  5. Metallomics:An integrated biometal science

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Metallomics is an emerging scientific area integrating the research fields related to the understanding of the molecular mechanisms of metal-associated life processes and the entirety of metal and metalloid species within a cell or tissue type. In metallomics,metalloproteins,metalloenzymes and other metal-containing biomolecules in a biological system are referred to as metallomes,similar to genomes and proteomes in genomics and proteomics,respectively. This review discusses the concept of metallomics with a focus on analytical techniques and methods,particularly the so-called hyphenated techniques which combine a high-resolution separation technique (gel electrophoresis/laser ablation,chromatography or capillary electrophoresis) with a highly sensitive detection method such as elemental (inductively coupled plasma,ICP) or molecular (electron spray ionization (ESI) or matrix-assisted laser desorption/ionization (MALDI)) mass spectrometry,or nuclear X-ray fluorescence/absorption spectrometry. The applications of these advanced analytical methods in the identification of metallo-/phospho-/seleno-proteins,probing of relationships between structure and function of metal-loproteins,and study of clinically used metallodrugs will be selectively outlined,along with their advantages and limitations.

  6. Punctuation as readability and textuality factor in technical discourse

    Directory of Open Access Journals (Sweden)

    Carmen Sancho Guinda

    2002-04-01

    Full Text Available This paper studies the incidence of punctuation on the reading comprehension of technical discourse and its role as a factor of textuality. Starting out from the notions of textuality and punctuation functions formulated by different linguistic approaches, an analysis has been made to quantify the decoding skills and punctuating competence of 60 Aeronautical Engineering students, as well as to determine the nature and effects of their punctuation errors. The survey has been focused on the Full Stop, the comma and the hyphen due to their highly conflicting uses as regards the identification of immediate sentence constituents and semantic relationships. The results obtained suggest that most students have a poor knowledge of punctuation rules and little awareness of punctuation as a textual elementaffecting readability. Errors are in the main related to comma use and produced by transference, either of Spanish punctuating habits into English, or of individual prosodic patterns into writing, while meaning appears to be the prevailing punctuating criterion over sound and syntax. Punctuation proves an effective tool for the anticipation of implicit meanings and an untapped resource in the teaching of the diverse communicative and stylistic possibilities offered by technical texts.

  7. Analytical methods for the extraction and identification of secondary metabolite production in 'in vitro' plant cell cultures.

    Science.gov (United States)

    Bertoli, Alessandra; Ruffoni, Barbara; Pistelli, Laura; Pistelli, Luisa

    2010-01-01

    The production of plant secondary metabolites by in vitro culture is one of the most challenging and thrilling field of recent scientific researches. In the few last years, pharmaceutical and food industry demand in phytochemicals has increased steadily. Therefore, the establishment of in vitro plant protocols has to be monitored by phytochemical investigation of their selected extracts in order to supply standardized raw material. In this chapter, the advantages and disadvantages of some modem techniques have been described for the sampling, extraction and analysis ofthe invitro plants and derivatives. Depending on the volatile or nonvolatile substances produced by in vitro plant raw material, different kinds of laboratory facilities are needed for the extraction and quali-quantitative analysis. Recent extraction technology such as accelerated solvent extraction or microwave assisted extraction in combination with hyphenated techniques such as gas chromathography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) represent a modern approach to perform fast and reproducible analytical methods for the quality control of secondary metabolite production in 'in vitro' plant material. PMID:21520717

  8. Medicinal plants in the treatment of women's disorders: Analytical strategies to assure quality, safety and efficacy.

    Science.gov (United States)

    Masullo, Milena; Montoro, Paola; Mari, Angela; Pizza, Cosimo; Piacente, Sonia

    2015-09-10

    During last decades an increasing number of herbal products specifically targeting women's disorders has appeared in the worldwide marketplace. This growth highlights the need for a critical evaluation of quality, safety and efficacy of these products. Analytical techniques applied to the quality control of the main medicinal plants used for women health (relief of menopause and menstrual related symptoms) have been reviewed. Thanks to the innovation in analytical technology, identification and detection of secondary metabolites dramatically improved. In particular, hyphenated techniques have proved to be the most suitable for the rapid identification of compounds in plant matrix. Moreover, taking into account that differences in sample quality are not only found in the main compounds or in the chemical markers but also in the low-concentration compounds, fingerprint analysis might be a simple way for identification and quality control of herbal products containing a large number of low amounts of unknown compounds. Furthermore in several papers the informations obtained from the analysis of a plant have been processed by statistical elaborations. Medicinal plants here discussed are classified on the basis of the chemical markers used for their quality control. PMID:25863356

  1. Extracellular synthesis of silver nanoparticles by novel Pseudomonas veronii AS41G inhabiting Annona squamosa L. and their bactericidal activity

    Science.gov (United States)

    Baker, Syed; Mohan Kumar, K.; Santosh, P.; Rakshith, D.; Satish, S.

    2015-02-01

    In present investigation extracellular synthesis of silver nanoparticles were synthesized using cell free supernatant of Pseudomonas veronii AS41G isolated from Annona squamosa L. The bacterium significantly reduced silver nitrate to generate silver nanoparticles which was characterized with hyphenated techniques. Synthesis of silver nanoparticles preliminary confirmed by UV-Visible spectrophotometry with the intense peak at 410 nm, Further FTIR analysis revealed the possible role of biomolecules in the supernatant responsible for mediating the nanoparticles formation. The XRD spectra exhibited the characteristic Bragg peaks of 1 0 0, 1 1 1, 2 0 0, and 2 2 0 facets of the face centred cubic symmetry of nanoparticles suggesting that these nanoparticles were crystalline in nature. TEM microgram showed polydispersity of nanoparticles with size ranging from 5 to 50 nm. Synthesized silver nanoparticles showed antibacterial activity against human and environmental pathogens including MRSA. The study enlightens the role of biosynthesized silver nanoparticles as an emerging alternative for drug resistant microorganisms. The obtained results are promising enough to pave the environmentally benign nanoparticle synthesis processes without use of any toxic chemicals and also envision the emerging role of endophytes towards synthesis of nanoparticles. With scanty reports available on P.veronii species, a new role has been reported in this study which will be very valuable for future researchers working on it.

  2. Análise de correspondência aplicada a avaliação da propaganda farmacêutica junto à classe médica

    Directory of Open Access Journals (Sweden)

    Carlos Alicio Nascimento

    2010-09-01

    Full Text Available

    A relação médico-paciente, substância essencial do ato médico, vem ao longo da evolução do exercício da medicina, sofrendo mudanças, perdendo a cada dia, características fundamentais, como a humanização, a ética e a comunicação. Aborda a questão da percepção do aluno da medicina sobre a relação médicopaciente, a importância da família nesta relação, e a experiencia do trabalho em equipe. A hipótese central e que o aluno desenvolvendo a prática de ensino no Programa Saude da Familia (PSF, modelo assistencial tendo como núcleo central a fam

  3. Sb(V reactivity with human blood components: redox effects.

    Directory of Open Access Journals (Sweden)

    Silvana López

    Full Text Available We assessed the reactivity of Sb(V in human blood. Sb(V reactivity was determined using an HPLC-HG-AFS hyphenated system. Sb(V was partially reduced to Sb(III in blood incubation experiments; however, Sb(III was a highly unstable species. The addition of 0.1 mol L(-1 EDTA prevented Sb(III oxidation, thus enabling the detection of the reduction of Sb(V to Sb(III. The transformation of Sb(V to Sb(III in human whole blood was assessed because the reduction of Sb(V in human blood may likely generate redox side effects. Our results indicate that glutathione was the reducing agent in this reaction and that Sb(V significantly decreased the GSH/GSSG ratio from 0.32 ± 0.09 to 0.07 ± 0.03. Moreover, the presence of 200 ng mL(-1 of Sb(V increased the activity of superoxide dismutase from 4.4 ± 0.1 to 7.0 ± 0.4 U mL(-1 and decreased the activity of glutathione peroxidase from 62 ± 1 to 34 ± 2 nmol min(-1 mL(-1.

  4. Novel approaches for selenium speciation in foodstuffs and biological specimens: A review

    International Nuclear Information System (INIS)

    Selenium is an essential element for human health. It has been recognized as an antioxidant and chemopreventive agent in cancer. Selenium is known to develop its biological activity via selenocysteine residue in the catalytically active centre of selenoproteins. The main source of selenium in human beings is the diet. However, in several regions of the world the content of selenium in diet has been estimated insufficient for a correct expression of the proteins. The beneficial effects of selenium on human health are strongly dependent on its chemical form and concentration. This review critically evaluated the state-of-the art of selenium speciation in biological matrices mainly focused in nutritional and food products. Besides the number of publications related to selenium speciation, isolation and accurate characterization and quantification of selenium species is still a challenge. Hyphenated techniques based on coupling chromatography separation with inductively coupled plasma spectrometry (ICP-MS) and its combination with molecular mass spectrometry (ESI-MS, ESI-MS-MS and MALDI-TOF) and isotopic dilution allow identification, quantification and structural characterization of selenium species. Particular attention is paid in the development of Se-enriched food and nutritional products and how the application of the techniques mentioned above is mandatory to get reliable results on selenium metabolisms in these particular matrices

  5. Recent trends in the impurity profile of pharmaceuticals

    Directory of Open Access Journals (Sweden)

    Kavita Pilaniya

    2010-01-01

    Full Text Available Various regulatory authorities such as the International Conference on Harmonization (ICH, the United States Food and Drug administration (FDA, and the Canadian Drug and Health Agency (CDHA are emphasizing on the purity requirements and the identification of impurities in Active Pharmaceutical Ingredients (APIs. The various sources of impurity in pharmaceutical products are - reagents, heavy metals, ligands, catalysts, other materials like filter aids, charcoal, and the like, degraded end products obtained during \\ after manufacturing of bulk drugs from hydrolysis, photolytic cleavage, oxidative degradation, decarboxylation, enantiomeric impurity, and so on. The different pharmacopoeias such as the British Pharmacopoeia, United State Pharmacopoeia, and Indian Pharmacopoeia are slowly incorporating limits to allowable levels of impurities present in APIs or formulations. Various methods are used to isolate and characterize impurities in pharmaceuticals, such as, capillary electrophoresis, electron paramagnetic resonance, gas-liquid chromatography, gravimetric analysis, high performance liquid chromatography, solid-phase extraction methods, liquid-liquid extraction method, Ultraviolet Spectrometry, infrared spectroscopy, supercritical fluid extraction column chromatography, mass spectrometry, Nuclear magnetic resonance (NMR spectroscopy, and RAMAN spectroscopy. Among all hyphenated techniques, the most exploited techniques for impurity profiling of drugs are Liquid Chromatography (LC-Mass Spectroscopy (MS, LC-NMR, LC-NMR-MS, GC-MS, and LC-MS. This reveals the need and scope of impurity profiling of drugs in pharmaceutical research.

  6. Multivariate curve resolution of incomplete fused multiset data from chromatographic and spectrophotometric analyses for drug photostability studies

    International Nuclear Information System (INIS)

    Highlights: • A new MCR-ALS algorithm is proposed for the analysis of incomplete fused multiset. • Resolution of the data allowed the description of amiloride kinetic photodegradation. • The new MCR-ALS algorithm can be easily applied to other drugs and chemicals. - Abstract: An advanced and powerful chemometric approach is proposed for the analysis of incomplete multiset data obtained by fusion of hyphenated liquid chromatographic DAD/MS data with UV spectrophotometric data from acid–base titration and kinetic degradation experiments. Column- and row-wise augmented data blocks were combined and simultaneously processed by means of a new version of the multivariate curve resolution-alternating least squares (MCR-ALS) technique, including the simultaneous analysis of incomplete multiset data from different instrumental techniques. The proposed procedure was applied to the detailed study of the kinetic photodegradation process of the amiloride (AML) drug. All chemical species involved in the degradation and equilibrium reactions were resolved and the pH dependent kinetic pathway described

  7. Biotransformation and Incorporation into Proteins along a Simulated Terrestrial Food Chain

    Energy Technology Data Exchange (ETDEWEB)

    Unrine, J.M., B.P. Jackson and W.A. Hopkins

    2007-01-01

    Selenium is an essential trace element in vertebrates, but there is a narrow concentration range between dietary requirement and toxicity threshold. Although a great deal is known about the biochemistry of Se from a nutritional perspective, considerably less attention has been focused on the specific biochemistry of Se as an environmental toxicant. Recent advances in hyphenated analytical techniques have provided the capability of quantifying specific chemical forms of Se in biological tissues as well as the distribution of Se among macromolecules. We applied liquid chromatography coupled to inductively coupled plasma mass spectrometry to investigate biotransformations of selenomethionine along a simulated terrestrial food chain consisting of selenomethionine exposed crickets (Acheta domesticus) fed to western fence lizards (Sceloporus occidentalis). Evidence was obtained for selenomethionine biotransformation as well as for sex-specific differences in the metabolism of Se compounds and their subsequent incorporation into proteins in the lizard. The results demonstrate the complexities involved in trophic transfer of Se due to the potential for extensive biotransformation and the species- and even sex-specific nature of these biotransformations.

  8. Online coupling of pure O2 thermo-optical methods - 14C AMS for source apportionment of carbonaceous aerosols

    Science.gov (United States)

    Agrios, Konstantinos; Salazar, Gary; Zhang, Yan-Lin; Uglietti, Chiara; Battaglia, Michael; Luginbühl, Marc; Ciobanu, Viorela Gabriela; Vonwiller, Matthias; Szidat, Sönke

    2015-10-01

    This paper reports on novel separation methods developed for the direct determination of 14C in organic carbon (OC) and elemental carbon (EC), two sub-fractions of total carbon (TC) of atmospheric air particulate matter. Until recently, separation of OC and EC has been performed off-line by manual and time-consuming techniques that relied on the collection of massive CO2 fractions. We present here two on-line hyphenated techniques between a Sunset OC/EC analyzer and a MICADAS (MIni radioCArbon DAting System) accelerator mass spectrometer (AMS) equipped with a gas ion source. The first implementation facilitates the direct measurement in the low sample size range (<10 μg C) with high throughput on a routine basis, while the second explores the potential for a continuous-flow real-time CO2 gas feed into the ion source. The performance achieved with reference materials and real atmospheric samples will be discussed to draw conclusions on the improvement offered in the field of 14C aerosol source apportionment.

  9. Ultra-Fast Sample Preparation for High-Throughput Proteomics

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Ferrer, Daniel; Hixson, Kim K.; Belov, Mikhail E.; Smith, Richard D.

    2011-06-21

    Sample preparation oftentimes can be the Achilles Heel of any analytical process and in the field of proteomics, preparing samples for mass spectrometric analysis is no exception. Current goals, concerning proteomic sample preparation on a large scale, include efforts toward improving reproducibility, reducing the time of processing and ultimately the automation of the entire workflow. This chapter reviews an array of recent approaches applied to bottom-up proteomics sample preparation to reduce the processing time down from hours to minutes. The current state-of-the-art in the field uses different energy inputs like microwave, ultrasound or pressure to perform the four basic steps in sample preparation: protein extraction, denaturation, reduction and alkylation, and digestion. No single energy input for enhancement of proteome sample preparation has become the universal gold standard. Instead, a combination of different energy inputs tend to produce the best results. This chapter further describes the future trends in the field such as the hyphenation of sample preparation with downstream detection and analysis systems. Finally, a detailed protocol describing the combined use of both pressure cycling technology and ultrasonic energy inputs to hasten proteomic sample preparation is presented.

  10. Atmospheric pressure gas chromatography coupled to quadrupole-time of flight mass spectrometry as a tool for identification of volatile migrants from autoadhesive labels used for direct food contact.

    Science.gov (United States)

    Canellas, Elena; Vera, Paula; Nerín, Cristina

    2014-11-01

    Pressure-sensitive adhesives (PSA) are used to manufacture labels that are applied directly on the food. These adhesives could contain not only intentionally added compounds (IAS) to the adhesive formula but also non-intentionally added substances (NIAS), due to the impurities from the raw materials used, decomposition of the initial components or from chemical interactions between them. These compounds could migrate to the food and contaminate it. In this study, gas chromatography coupled with mass spectrometry (GC-MS/Q) and atmospheric pressure gas chromatography coupled to a quadrupole hyphenated to a time of flight mass spectrometer (APGC-MS/Q-TOF) have been used for identification of unknown compounds and NIAS coming from a PSA. Seven compounds were identified by GC-MS/Q, and other eight compounds remained initially unknown. The structure of these eight new compounds was elucidated by working with the spectra obtained by APGC-MS/Q-TOF. Finally, two different migration studies were carried out. The first one with Tenax as solid food simulant in contact with the paper label containing the adhesive and the second one with isooctane filled in a natural pork intestine where the label containing the adhesive was applied on the external side. The results are shown and discussed. PMID:25395134

  11. Analytical developments for the speciation of uranium in zebra fish (Danio rerio) gills after exposure

    International Nuclear Information System (INIS)

    The objective of this thesis is to study the cellular compartmentalization and the chelation of uranium (U) by cytosolic proteins of gill cells of the zebra fish (Danio rerio, model specie in aquatic toxicology) under different direct exposure conditions (chronic vs. acute, 20 and 250 μg.L-1). This study required the development of hyphenated techniques (SEC, IEF off-gel, RP-UHPLC for the separation, ICP-SFMS, ESI-FTMS/MS for the detection) with the main challenges of maintaining the non-covalent U-biomolecule interactions and enhancing sensitivity for the analysis of environmentally relevant samples. After extraction, 24% to 32% of the total U detected in the gills were present in the cytosolic fraction, in which the U distribution on the biomolecules (as a function of their MW and pI) varied depending on the exposure level. Finally, U target biomolecules mapping allowed us (i) to highlight a particular affinity of U for acidic and/or P-containing proteins and (ii) to identify 24 protein candidates for U binding. (author)

  12. Profiling the substitution pattern of xyloglucan derivatives by integrated enzymatic hydrolysis, hydrophilic-interaction liquid chromatography and mass spectrometry.

    Science.gov (United States)

    Liu, Jun; Kisonen, Victor; Willför, Stefan; Xu, Chunlin; Vilaplana, Francisco

    2016-09-01

    Plant polysaccharides constitute arguably the most complex family of biomacromolecules in terms of the stereochemistry and regiochemistry of their intramolecular linkages. The chemical modification of such polysaccharides introduces an additional level of complexity for structural determinations. We have developed an integrated analytical procedure combining selective enzymatic hydrolysis, hydrophilic interaction liquid chromatography (HILIC), and mass spectrometry (MS) to describe the substitution pattern of xyloglucan (XyG) and its chemo-enzymatic derivatives (cationic, anionic, and benzyl aminated). Enzymatic hydrolysis of XyG derivatives by a xyloglucan-specific endoglucanase (XEG) generates oligosaccharides amenable for mass spectrometric identification with distinct structures, based on enzymatic substrate recognition and hydrolytic pattern. Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-ToF-MS) and electrospray ionisation mass spectrometry (ESI-MS) offer qualitative mass profiling of the chemical derivatives. Separation and identification of the complex oligosaccharide profiles released by enzymatic hydrolysis is achieved by hyphenation of hydrophilic interaction liquid chromatography with mass spectrometry (HILIC-ESI-MS). Further fragmentation by tandem mass spectrometry (ESI-MS/MS) in positive mode enables the structural sequencing of modified XyG oligosaccharides and the identification of the substituent position without further derivatisation. This integrated approach can be used to obtain semi-quantitative information of the substitution pattern of hemicellulose derivatives, with fundamental implications for their modification mechanisms and performance. PMID:27524300

  13. On the frontiers of knowledge: the enlargement of experience and the new forms of rationality doi:10.5007/1807-1384.2010v7n2p1

    Directory of Open Access Journals (Sweden)

    Ivan Domingues

    2010-12-01

    Full Text Available The article discusses the panorama of knowledge today, focusing on the inflation of knowledge, the fragmentation of disciplines and the density loss of cognitive processes as well as the search for alternatives through multi-, inter- and transdisciplinary experiments. Other points emphasized: the emergence of the hyphenated disciplines (bio-chemistry, ethno-music, etc.; the approach of science, technology, art and philosophy; the end of the generalist and the specialist. The sense of the analyses is epistemological and the goal is to demonstrate, in contrast, two real approaches that define cognitive strategies in different fields of knowledge: the reductionist and the non-reductionist. The stress falls on the non-reductionist approaches, highlighting the following topics or aspects: the dilatation of the experience and the expansion of reason, the conquest of different levels of reality, new perspectives for the humanities and social sciences. Finally, after emphasizing the importance of discipline, its centrality anchor is placed in context, through the recognition of themes and issues as important challenges and opportunities acquis, enabling the advancement of knowledge.

  14. Recent advances in CE-MS: Synergy of wet chemistry and instrumentation innovations.

    Science.gov (United States)

    Pantůčková, Pavla; Gebauer, Petr; Boček, Petr; Křivánková, Ludmila

    2011-01-01

    CE with MS detection is a hyphenated technique which greatly improves the ability of CE to deal with real samples, especially with those coming from biology and medicine, where the target analytes are present as trace amounts in very complex matrices. CE-MS is now almost a routine technique performed on commercially available instruments. It faces currently a tremendous development of the technique itself as well as of its wide application area. Great interest in CE-MS is reflected in the scientific literature by many original research articles and also by numerous reviews. The review presented here has a general scope and belongs to a series of regularly published reviews on the topic. It covers the literature from the last 2 years, since January 2008 till June 2010. It brings a critical selection of related literature sorted into groups reflecting the main topics of actual scientific interest: (i) innovations in CE-ESI-MS, (ii) use of alternative interfaces, and (iii) ways to enhance sensitivity. Special attention is paid to novel electrolyte systems amenable to CE-MS including nonvolatile BGEs, to advanced CE separation principles such as MEKC, MEEKC, chiral CE, and to the use of preconcentration techniques. PMID:21171112